Wednesday, December 13, 2006

CANCER OF THE MOUTH AND THROAT



The oral cavity (mouth) and the upper part of the throat (pharynx) have roles in many important functions, including breathing, talking, chewing, and swallowing. The mouth and upper throat are sometimes referred to as the oropharynx. The important structures of the mouth and upper throat include the following:
•Lips
•Inside lining of the cheeks (buccal mucosa)
•Teeth
•Gums
•Tongue
•Floor of the mouth
•Back of the throat, including the tonsils (oropharynx)
•Roof of the mouth (the bony front part [hard palate] and the softer rear part [soft palate])
•Area behind the wisdom teeth
•Salivary glands
Many different cell types make up these different structures. Cancer occurs when normal cells undergo a transformation whereby they grow and multiply without normal controls.
•As the cells multiply, they form small abnormalities called lesions. Eventually, they form a mass called a tumor.
•Tumors are cancerous only if they are malignant. This means that, because of their uncontrolled growth, they encroach on and invade neighboring tissues.
•Malignant tumors may spread to neighboring tissues by direct invasion or by traveling along lymphatic vessels and nerves or through the blood stream.
•They may also travel to remote organs via the bloodstream.
•This process of invading and spreading to other organs is called metastasis.
•Tumors overwhelm surrounding tissues by invading their space and taking the oxygen and nutrients they need to survive and function.
Tumors in the mouth and throat include both benign and malignant types.
•Benign tumors, although they may grow and penetrate below the surface layer of tissue, do not spread by metastasis to other parts of the body.
•Benign tumors of the oropharynx are not discussed here.
Premalignant conditions are cell changes that are not cancer but which may become cancer if not treated.
•Dysplasia is another name for these precancerous cell changes.
•Dysplasia can be detected only by taking a biopsy of the lesion. This means to collect a tiny sample of the abnormal area.
•Examining the dysplastic cells under a microscope indicates how severe the changes are and how likely the lesion is to become cancerous.
•The dysplastic changes are usually described as mild, moderately severe, or severe.
The 2 most common kinds of premalignant lesions in the oropharynx are leukoplakia and erythroplakia.
•Leukoplakia is a white or whitish area. It can often be easily scraped off without bleeding. Only about 5% of leukoplakias are cancerous at diagnosis or will become cancerous within 10 years if not treated.
•Erythroplakia is a raised, red area. If scraped, it may bleed. Erythroplakia is generally more severe than leukoplakia and has a higher chance of becoming cancerous over time.
•These are often detected by a dentist at a routine dental examination.
Several types of malignant cancers occur in the mouth and throat.
•Squamous cell carcinoma is by far the most common type, accounting for more than 90% of all cancers. These cancers start in the squamous cells, which form the surface of much of the lining of the mouth and pharynx. They can invade deeper layers below the squamous layer.
•Other less common cancers of the mouth and throat include minor salivary gland tumors and lymphoma.
•Cancers of the mouth and throat do not always metastasize, but those that do usually spread first to the lymph nodes of the neck. From there, they may spread to more distant parts of the body.
About 27,700 new cases of oral cancer will be diagnosed in the United States in 2003. Approximately 7,200 people will die of these cancers during the same period.
•The incidence and death rates attributable to oral cancers have been gradually decreasing over the past 20 years.
•Cancers of the mouth and throat occur in twice as many men as women.
•These cancers can develop at any age but occur most frequently in people aged 45 years and older.
•Incidence rates of mouth and throat cancers vary widely from country to country. These variations are due to differences in risk factor exposures.
Cancer Causes
Tobacco use is by far the most common risk factor for cancers of the mouth and throat. Both smoking and “smokeless” tobacco (snuff and chewing tobacco) increase the risk of developing cancer in the mouth or throat.
•All forms of smoking are linked to these cancers, including cigarettes, cigars, and pipes. Tobacco smoke can cause cancer anywhere in the mouth and throat as well as in the lungs, the bladder, and many other organs in the body. Pipe smoking is particularly linked with lesions of the lips, where the pipe comes in contact with the tissue.
•Smokeless tobacco is linked with cancers of the cheeks, gums, and inner surface of the lips. Cancers caused by smokeless tobacco use often begin as leukoplakia or erythroplakia.
Other risk factors for mouth and throat cancer include the following:
•Alcohol use: At least three quarters of people who have a mouth and throat cancer consume alcohol frequently. People who drink alcohol frequently are 6 times more likely to develop one of these cancers. People who both drink alcohol and smoke often have a much higher risk than people who use only tobacco alone.
•Ultraviolet light exposure: People who spend a lot of time in sunlight, such as those who work outdoors, are more likely to have cancer of the lip.
•Chewing betel nut, a prevalent practice in India and other parts of South Asia, has been found to result in mucosa carcinoma of the cheeks. Mucosa carcinoma accounts for less than 10% of oral cavity cancers in the United States but is the most common oral cavity cancer in India.
•Human papillomavirus (HPV) infection: Several strains of HPV are associated with cancers of the cervix, vagina, vulva, and penis. The link between HPV and oral cancers is not known, but HPV infection is believed to increase the risk of oral cancers in some people.
These are risk factors that can be avoided in some cases. For example, you can choose to not smoke, thus lowering your risk of mouth and throat cancer. The following risk factors are outside of your control:
•Age: The incidence of mouth and throat cancers increases with advancing age.
•Sex: Mouth and throat cancer is twice as common in men as in women. This may be related to the fact that more men than women use tobacco and alcohol.
The relationship between these risk factors and an individual’s risk is not well understood. Many people who have no risk factors develop mouth and throat cancer. Conversely, many people with several risk factors do not. In large groups of people, these factors are linked with higher incidence of oropharyngeal cancers.

Mouth and Throat Cancer Symptoms
People with an oropharyngeal cancer may notice any of the following symptoms:
•A painless lump on the lip, in the mouth, or in the throat
•A sore on the lip or inside the mouth that does not heal
•A painless white or red patch on the gums, tongue, or lining of the mouth
•Unexplained pain, bleeding, or numbness inside the mouth
•A sore throat that does not go away
•Pain or difficulty with chewing or swallowing
•Swelling of the jaw
•Hoarseness or other change in the voice
•Pain in the ear
These symptoms are not necessarily signs of cancer. They may be caused by many other less serious conditions.
When to Seek Medical Care
If you have any of the symptoms of head and neck cancer, make an appointment to see your primary care provider or your dentist right away.

Exams and Tests
Cancers of the mouth and throat are often found on routine dental examination. If your dentist should find an abnormality, he or she will probably refer you to a specialist in ear, nose, and throat medicine (an otolaryngologist) or recommend that you see your primary health care provider right away.
If you have symptoms that suggest a possible cancer, or if an abnormality is found in your oral cavity or pharynx, your health care provider will immediately begin the process of identifying the type of abnormality.
•The goal will be to rule out or confirm the diagnosis of cancer.
•He or she will interview you extensively, asking questions about your medical and surgical history, the medications you take, your family and work history, and your habits and lifestyle, focusing on the risk factors for oropharyngeal cancers.
At some point during this process, you will probably be referred to a physician who specializes in treating cancers of the mouth and throat.
•Many cancer specialists (oncologists) specialize in treating cancers of the head and neck, which includes cancers of the oropharynx.
•It is your right to seek treatment where you wish.
•You may want to consult with two or more specialists to find one who makes you feel most comfortable.
You will undergo a thorough examination of the head and neck to look for lesions and abnormalities. A mirror exam and/or an indirect laryngoscopy (see below for explanation) will most likely be done to view areas that are not directly visible on examination, such as the back of the nose (nasopharyngoscopy), the throat (pharyngoscopy), and the voice box (laryngoscopy).
•The indirect laryngoscopy is performed with the use of a thin, flexible tube containing fiberoptics connected to a camera. The tube is moved through the nose and throat and the camera sends images to a video screen. This allows your physician to see any hidden lesions.
•In some cases, a panendoscopy may be necessary. This includes endoscopic examination of the nose, throat, and voice box as well as the esophagus and airways of the lungs (bronchi). This is done in an operating room while you are under general anesthesia. This gives the most exhaustive possible examination and can permit biopsies of areas suspicious for malignancy.
•The complete physical examination will look for signs of metastatic cancer or other medical conditions that could affect the diagnosis or treatment plan.
No blood tests can identify or even suggest the presence of a cancer of the mouth or throat. The appropriate next step is biopsy of the lesion. This means to remove a sample of cells or tissue (or the entire visible lesion if small) for examination.
•There are several techniques for taking a biopsy in the mouth or throat. The sample can be simply scraped from the lesion, removed with a scalpel, or withdrawn with a needle.
•This can sometimes be done in the medical office; other times, it needs to be done in a hospital.
•The technique is dictated by the size and location of the lesion and by the experience of the person collecting the biopsy.
•If you have a mass in your neck, that may be sampled as well, usually by fine-needle aspiration biopsy.
After the sample(s) is removed, it will be examined by a doctor who specializes in diagnosing diseases by examining cells and tissues (pathologist).
•The pathologist looks at the tissue under a microscope after treating it with special stains to highlight certain abnormalities.
•If the pathologist finds cancer, he or she will identify the type of cancer and report back to your health care provider.
If your lesion is cancer, the next step is to stage the cancer. This means to determine the size of the tumor and its extent, that is, how far it has spread from where it started. Staging is important because it not only dictates the best treatment but also your prognosis for survival after treatment.
•In oropharyngeal cancers, the stage is based on the size of the tumor, involvement of the lymph nodes in the head and neck, and evidence of spread to distant parts of the body.
•Like many cancers, cancers of the oral cavity and pharynx are staged as 0, I, II, III, and IV, with 0 being the least severe (cancer has not yet invaded the deeper layers of tissue under the lesion) and IV being the most severe (cancer has spread to an adjacent tissue, such as the bones or skin of the neck, to many lymph nodes on the same side of the body as the cancer, to a lymph node on the opposite side of the body, to involve critical structures such as major blood vessels or nerves, or to a distant part of the body).
Stage is determined from the following information:
•Physical examination findings
•Endoscopic findings
•Imaging studies - X-rays (including a Panorex, a panoramic dental x-ray), CT scan, MRI, and, occasionally, a nuclear medicine scan of the bones to detect metastatic disease

Mouth and Throat Cancer Treatment
After you have been evaluated by a surgical or radiation oncologist to treat your cancer, you will have ample opportunity to ask questions and discuss which treatments are available to you.
•Your doctor will present each type of treatment, give you the pros and cons, and make recommendations.
•Treatment for head and neck cancer depends on the type of cancer and whether it has affected other parts of the body. Factors such as your age, your overall health, and whether you have already been treated for the cancer before are included in the treatment decision-making process.
•The decision of which treatment to pursue is made with your doctor (with input from other members of your care team) and your family members, but ultimately, the decision is yours.
•Be certain you understand exactly what will be done and why, and what you can expect from your choices. With oral cancers, it is especially important to understand the side effects of treatment.
Like many cancers, head and neck cancer is treated on the basis of cancer stage. The most widely used therapies are surgery and radiation therapy. Chemotherapy is used in some advanced cases. Your treatment plan will be individualized for your specific situation.
•Your medical team may include an ear, nose, and throat surgeon; an oral surgeon; a plastic surgeon; and a specialist in prosthetics of the mouth and jaw (prosthodontist), as well as a specialist in radiation therapy (radiation oncologist) and medical oncology.
•Because cancer treatment can make your mouth sensitive and more likely to be infected, your doctor will probably advise you to have any needed dental work done before your treatment.
•Your team will also include a dietitian to ensure that you get adequate nutrition during and after your therapy.
•A speech therapist may be needed to help you recover your speech or swallowing abilities after treatment.
•A physical therapist may be needed to help you recover function compromised by loss of muscle or nerve activity from the surgery.
•A social worker, counselor, or member of the clergy will be available to help you and your family cope with the emotional, social, and financial toll of your treatment.
Medical Treatment
Your treatment falls into 2 categories: treatment to fight the cancer and treatment to relieve the symptoms of the disease and the side effects of the treatment (supportive care).
Surgery is the treatment of choice for early stage cancers and many later stage cancers. The tumor is removed, along with surrounding tissues, including but not limited to the lymph nodes, blood vessels, nerves, and muscles that are affected. For more information, see Surgery.
Radiation therapy involves the use of a high-energy beam to kill cancer cells.
•Radiation can be used instead of surgery for many stage I and II cancers, because surgery and radiation have equivalent survival rates in these tumors. In stage II cancers, tumor location determines the best treatment. The treatment that will have the fewest side effects is usually chosen.
•Stage III and IV cancers are most often treated with both surgery and radiation. The radiation is typically given after surgery. Radiation after surgery kills any remaining cancer cells.
•External radiation is given by precisely targeting a beam at the tumor. The beam goes through the healthy skin and overlying tissues to reach the tumor. These treatments are given at the cancer center. Treatments are usually given once a day, 5 days a week, for about 6 weeks. Each treatment takes only a few minutes. Giving radiation this way keeps the doses small and helps protect healthy tissues. Some cancer centers are experimenting with giving radiation twice a day to see if it increases survival rates.
•Unfortunately, radiation affects healthy cells as well as cancer cells. Damage to healthy cells accounts for the side effects of radiation therapy. These include sore throat, dry mouth, cracked and peeling lips, and a sunburn-like effect on the skin. It can cause problems with eating, swallowing, and speaking. You may also feel very tired during, and for some time after, these treatments. External beam radiation can also affect the thyroid gland in the neck, causing your level of thyroid hormone to be low. This can be treated.
•Internal radiation therapy (brachytherapy) can avoid these side effects in some cases. This involves implanting tiny radioactive "seeds" directly into the tumor or in the surrounding tissue. The seeds emit radiation that destroys tumor cells. This treatment takes several days, and you will have to stay in the hospital during the treatment.
Chemotherapy is the use of powerful drugs to kill cancer cells.
•Chemotherapy alone may shrink these tumors, but the effect does not last for long.
•In head and neck cancers, chemotherapy is used in combination with radiation therapy and surgery for large or extensive cancers and in combination with radiation therapy in other head and neck cancers depending on the site.
•The side effects depend on which drugs are given. Common side effects include nausea and vomiting, severe heartburn-type pain, diarrhea, hair loss, mouth sores, loss of appetite, fatigue or weakness, and increased risk of infection.
Treatment of recurrent tumors, like that of primary tumors, varies by size and location of the recurrent tumor. The treatment given previously is also taken into account. For instance, a site already treated by external radiation therapy may be difficult to treat a second time with external radiation.
Weight loss is a common effect in people with head and neck cancers. Discomfort from the tumor itself, as well as the effects of treatment on the chewing and swallowing structures and the digestive tract, often prevents eating.
Medications will be offered to treat some of the side effects of therapy, such as nausea, dry mouth, mouth sores, and heartburn.
You will probably see a speech therapist during and for some time after treatment. The speech therapist helps you learn to cope with the changes in your mouth and throat after treatment so that you can eat, swallow, and talk.

Surgery
Oral surgery for cancer may be simple or very complicated. This depends on how far the cancer has spread from where it started.
•Cancers that have not spread can often be removed quite easily, with minimal scarring or change in appearance.
•If the cancer has spread to other structures, those structures must also be removed. This may include small muscles in the neck, lymph nodes in the neck, salivary glands, and nerves and blood vessels that supply the face. Structures of the jaw, chin, and face, as well as teeth and gums, may also be affected.
If any of these structures are removed, your appearance will change. The surgery will also leave scars that may be visible. These changes can sometimes be extensive. A plastic surgeon may take part in the planning or in the operation itself to minimize these changes. Reconstructive surgery may be an option to restore tissues removed or altered by surgery.
Removal of tissues and the resulting scars can cause problems with the normal functions of your mouth and throat. These disruptions may be either temporary or permanent. Chewing, swallowing, and speaking are the functions most likely to be disrupted.
Next Steps:-Follow-up

After surgery, you will see your surgeon, radiation oncologist, or both if you received chemotherapy. You will also follow-up with your medical oncologist.
You will also continue to see your medical oncologist according to a schedule he or she will recommend.
•You may go through staging tests after completing treatment to determine how well the treatment worked and if you have any residual cancer.
•Thereafter, at regular visits, you will undergo physical examination and testing to make sure the cancer has not come back and that a new cancer has not appeared.
•At least 5 years of follow-up care is recommended, and many people choose to continue these visits indefinitely.
•Report any new symptoms to your oncologist immediately—Do not wait for the next visit.
Speech and swallowing therapy will continue for as long as needed to restore these functions
Prevention
The best way to prevent head and neck cancer is to avoid the risk factors.
•If you use tobacco, quit. Do not substitute “smokeless” tobacco for smoking. Pipe and cigar smoking are not safer than cigarette smoking.
•If you drink alcohol, do so in moderation. Do not use both tobacco and alcohol.
•If you work outdoors or are otherwise frequently exposed to sunlight (ultraviolet radiation), protect yourself with clothing that blocks the sun. Apply sunscreen to your face (including a lip balm with sunscreen), and wear a wide-brimmed hat.
•Avoid sources of oral irritation, such as ill-fitting dentures. If you wear dentures, remove and clean them every day. Have your dentist check their fit regularly.
•Eat a balanced diet to avoid vitamin and other nutritional deficiencies. Make sure you eat foods with plenty of vitamin A, including fruits, vegetables, and supplemented dairy products. Do not take very high doses of vitamin A supplements, which may actually be harmful.
Ask your dentist or primary care provider to check your oral cavity and pharynx regularly to look for precancerous lesions and other abnormalities. Report any symptoms such as persistent pain, hoarseness, bleeding, or difficulty swallowing.

Outlook
The average 5-year survival rate for people who undergo treatment for head and neck cancer has been reported at 56%. The 10-year survival rate is 41%. About 80% of people treated for these cancers survive for at least 1 year. More accurate percentages depend on the tumor location, staging, type of treatment, and the presence of other medical conditions.
People with a mouth and throat cancer have a chance of developing another head and neck cancer or cancer in a neighboring region such as the voice box (larynx) or esophagus (the tube between the throat and the stomach). Regular follow-up examinations and prevention are extremely important.
Support Groups and Counseling
Living with cancer presents many new challenges for you and for your family and friends.
•You will probably have many worries about how the cancer will affect you and your ability to "live a normal life," that is, to care for your family and home, to hold your job, and to continuing the friendships and activities you enjoy.
•Many people feel anxious and depressed. Some people feel angry and resentful; others feel helpless and defeated.
For most people with cancer, talking about their feelings and concerns helps.
•Your friends and family members can be very supportive. They may be hesitant to offer support until they see how you are coping. Don't wait for them to bring it up. If you want to talk about your concerns, let them know.
•Some people don't want to "burden" their loved ones, or they prefer talking about their concerns with a more neutral professional. A social worker, counselor, or member of the clergy can be helpful if you want to discuss your feelings and concerns about having cancer. Your doctor should be able to recommend someone.
•Many people with cancer are profoundly helped by talking to other people who have cancer. Sharing your concerns with others who have been through the same thing can be remarkably reassuring. Support groups of people with cancer may be available through the medical center where you are receiving your treatment. The American Cancer Society also has information about support groups all over the United States.

For More Information
For more information about support groups, contact the following agencies:
•American Cancer Society - (800) ACS-2345
•National Cancer Institute, Cancer Information Service - (800) 4-CANCER [(800) 422-6237)]; TTY (for deaf and hard-of-hearing callers) (800) 332-8615

Web Links
American Academy of Otolaryngology—Head and Neck Surgery
American Cancer Society
American Speech-Language-Hearing Association - For information on problems after cancer treatment
National Cancer Institute
National Institute of Health's Clinical Trials database – For information about clinical trials in cancer treatment

Synonyms and Keywords
buccal mucosa, cigarette smoking, dysplasia, erythroplakia, hard palate, head and neck cancer, leukoplakia, lips, mouth, oral cancer, oral cavity, oropharyngeal cancer, oropharynx, pharynx, precancerous lesion, premalignant lesion, salivary glands, smokeless tobacco, smoking, soft palate, squalors cell carcinoma, throat, tongue, tonsils, cancer of the mouth and throat, mouth cancer, throat cancer

Authors and Editors
Author: Prajoy Kadkade, MD, Assistant Professor of Surgery, Division of Otolaryngology/Head & Neck Surgery, Department of Surgery, State University of New York at Stony Brook Medical Center and affiliated Northport Veterans Affairs Medical Center.

Coauthor(s): Kathryn L Hale, MS, PA-C, Medical Writer, eMedicine.com, Inc.

Editors: William M Lydiatt, MD, Associate Professor, Department of Otolaryngology-Head and Neck Surgery, University of Nebraska Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Rick Kulkarni, MD, Assistant Professor of Medicine, David Geffen UCLA School of Medicine; Director of Informatics, Department of Emergency Medicine, UCLA/Olive View-UCLA Medical Center.

Friday, December 1, 2006

COMPANY REGISTRATION


Introduction - Forming A Company In India

The Companies Act of 1956 sets down rules for the establishment of both public and private companies. The most commonly used corporate form is the limited company, unlimited companies being relatively uncommon. A company is formed by registering the Memorandum and Articles of Association with the State Registrar of Companies of the state in which the main office is to be located.
Foreign companies engaged in manufacturing and trading activities abroad are permitted by the Reserve Bank of India to open branch offices in India for the purpose of carrying on the following activities in India:
# To represent the parent company or other foreign companies in various matters in India, for example, acting as buying/selling agents in India, etc.
# To conduct research work in which the parent company is engaged provided the results of the research work are made available to Indian companies
# to undertake export and import trading activities
# to promote possible technical and financial collaboration between Indian companies and overseas companies.
Application for permission to open a branch, a project office or liaison office is made via the Reserve Bank of India by submitting form FNC-5 to the Controller, Foreign Investment and Technology Transfer Section of the Reserve Bank of India. For opening a project or site office, application may be made on Form FNC-10 to the regional offices of the Reserve Bank of India. A foreign investor need not have a local partner, whether or not the foreigner wants to hold full equity of the company. The portion of the equity thus not held by the foreign investor can be offered to the public.
Incorporating a Company - Approval of Name

The first step in the formation of a company is the approval of the name by the Registrar of Companies (ROC) in the State/Union Territory in which the company will maintain its Registered Office. This approval is provided subject to certain conditions: for instance, there should not be an existing company by the same name. Further, the last words in the name are required to be "Private Ltd." in the case of a private company and "Limited" in the case of a Public Company. The application should mention at least four suitable names of the proposed company, in order of preference. In the case of a private limited company, the name of the company should end with the words "Private Limited" as the last words. In case of a public limited company, the name of the company should end with the word "Limited" as the last word. The ROC generally informs the applicant within seven days from the date of submission of the application, whether or not any of the names applied for is available. Once a name is approved, it is valid for a period of six months, within which time Memorandum of Association and Articles of Association together with miscellaneous documents should be filed. If one is unable to do so, an application may be made for renewal of name by paying additional fees. After obtaining the name approval, it normally takes approximately two to three weeks to incorporate a company depending on where the company is registered.
Memorandum and Articles

The Memorandum of Association and Articles of Association are the most important documents to be submitted to the ROC for the purpose of incorporation of a company. The Memorandum of Association is a document that sets out the constitution of the company. It contains, amongst others, the objectives and the scope of activity of the company besides also defining the relationship of the company with the outside world.
The Articles of Association contain the rules and regulations of the company for the management of its internal affairs. While the Memorandum specifies the objectives and purposes for which the Company has been formed, the Articles lay down the rules and regulations for achieving those objectives and purposes.
The ROC will give the certificate of incorporation after the required documents are presented along with the requisite registration fee, which is scaled according to the share capital of the company, as stated in its Memorandum. A private company can commence business on receipt of its certificate of incorporation.
A public company has the option of inviting the public for subscription to its share capital. Accordingly, the company has to issue a prospectus, which provides information about the company to potential investors. The Companies Act specifies the information to be contained in the prospectus.
The prospectus has to be filed with the ROC before it can be issued to the public. In case the company decides not to approach the public for the necessary capital and obtains it privately, it can file a "Statement in Lieu of Prospectus" with the ROC.
On fulfillment of these requirements, the ROC issues a Certificate of Commencement of Business to the public company. The company can commence business immediately after it receives this certificate.
Certificate of Incorporation

After the duly stamped Memorandum of Association and Articles of Association, documents and forms are filed and the filing fees are paid, the ROC scrutinizes the documents and, if necessary, instructs the authorised person to make necessary corrections. Thereafter, a Certificate of Incorporation is issued by the ROC, from which date the company comes in to existence. It takes one to two weeks from the date of filing Memorandum of Association and Articles of Association to receive a Certificate of Incorporation. Although a private company can commence business immediately after receiving the certificate of incorporation, a public company cannot do so until it obtains a Certificate of Commencement of Business from the ROC.
Miscellaneous Documents

The documents/forms stated below are filed along with Memorandum of Association and Articles of Association on payment of filing fees (depending on the authorised capital of the company):
# Declaration of compliance, duly stamped
# Notice of the situation of the registered office of the company
# Particulars of Directors, Manager or Secretary
# Authority executed on a non-judicial stamp paper, in favour of one of the subscribers to the Memorandum of Association or any other person authorizing him to file the documents and papers for registration and to make necessary corrections, if any
# The ROC’s letter (in original) indicating the availability of the name.
Tax Registration

Businesses liable for income tax must obtain a tax identification card and number [known as Permanent Account Number (PAN)] from the Revenue Department. In addition to this, businesses liable to withhold tax must necessarily obtain a Tax Deduction Account Number (TAN). Both the PAN and the TAN must be indicated on all the returns, documents and correspondence filed with the Revenue Department. The PAN is also required to be stated in various other documents such as the documents pertaining to sale or purchase of any immovable property (exceeding Rs. five lakh), sale or purchase of a motor vehicle, time deposit (exceeding Rs. 5 lakh), contract for sale or purchase of securities (exceeding Rs. 10 lakh), to name a few.
Rules Applicable

Companies (Central Governments') General Rules and Forms,1956
Filing Registering/Approving Authority

One copy has to be submitted along with a forwarding letter addressed to the concerned Registrar of Companies.
Enclosures

The declaration must be submitted with the following annexures
# Document evidencing payment of fee
# Memorandum and Articles of Association
# Copy of agreement if any, which the proposed company wishes to enter into with any individual for appointment as its managing or whole-time director or manager
# Form 18
# Form 32 (except for section 25 company)
# Form 29 (only in case of public companies)
# Power of Attorney from subscribers
# Letter from Registrar of Companies making names available
# No objection letters from directors/promoters
# Requisite fees either in cash or demand draft
Fees

Fee payable depends on the nominal capital of the company to be registered and may be paid in one of the following modes. Cash/postal order (upto Rs.501-), demand draft favouring Registrar of Companies/Treasury Challan should be payable into specified branches of Punjab National Bank for credit
Time-Limit / Practice Notes

Time-Limit
It should be submitted before incorporation or within 6 months of the name being made available. Top
Practice Notes
The declaration has to be signed by an advocate of Supreme Court or High Court or an attorney or pleader entitled to appear before the High Court or a secretary or chartered accountant in whole-time practice in India who is engaged in the formation of the proposed company or person named in the articles as director, manager or secretary.
The Registrar of Companies has to be satisfied that not only the requirements of section 33(1) and (2) have been complied with but be also satisfied that provisions relating to number of subscribers, lawful nature of objects and name are complied with.
The Registrar will check whether the documents have been duly stamped and also whether the requirements of other laws are met.
Any defect in any of the documents filed has to be rectified either by all the subscribers or their attorney, or by any one subscriber holding the power of attorney on behalf of other subscribers.
This form is to be presented to the Registrar of Companies within three months from the date of letter of Registrar allowing the name.
This declaration is to be given on a non-judicial stamp paper of the requisite value . The stamp paper should be purchased in the name of the person signing the declaration.
This declaration is to be given by all the companies at, the time of registration, public or private.
The place of Registration No. of the company should be filled up by mentioning New Company therein.
The Registrar of Companies will now accept computer laser printed documents for purposes of registration provided the documents are neatly and legibly printed and comply with the other requirements of the Act. This will be an additional option available to the public to use laser print besides offset printing for submitting the memorandum and articles for the registration of companies.
Where the executant of a memorandum of association is illiterate, he shall give his thumb impression or marks which should be described as such by the subscriber or person writing for him.
An agent may sign a memorandum on behalf of a subscriber if he is authorised by a power-of-attorney to do so. In the case of an illiterate subscriber to the memorandum and articles of association, the thumb impression or mark duly attested by the person writing for him should be given. The person attesting the thumb mark should make an endorsement on the document to the effect that it has been read and explained to the subscriber. The Registrar of Companies will not accept zerox copies of the memorandum and articles of association for the purposes of registration of companies.
Presented by

This declaration is to be presented by the person signing the declaration or by his bearer at the counter of the Registrar of Companies office.
Managerial Remuneration

# Any person in order to be appointed as the Managing Director of the company should be a resident of India. Any person, being a non-resident in India, must obtain an Employment Visa from the concerned Indian mission abroad at the time of their appointment as the Managing Director.
# Whereas private companies are free to pay any remuneration to its directors, public companies can remunerate their directors only within the specified limits.
# In case of public companies, in the event of absence or inadequacy of net profits in any financial year, managerial remuneration is limited to amounts varying from Rs 75,000 to Rs 2,00,000 per month, depending on the effective capital of the company. In case of an expatriate managerial person, perquisites in the form of children’s education allowance, holiday passage money and leave travel concession provided to him would not form part of the said ceiling of remuneration.
# In case of a managerial position in two companies, remuneration can be drawn from one or both companies provided that the total remuneration drawn from the companies does not exceed the higher maximum limit admissible from any one of the companies of which he is a managerial person.
With whom to be filed

With the Registrar of Companies of the State in which the company is to be registered.
Documents required to be submitted
# A printed copy each of the Memorandum and Articles of Association of the proposed company filed along with the declaration duly stamped with the requisite value of adhesive stamps from the State/ Union Territory Treasury (For value of stamps to be affixed see Schedule printed in Part III Chapter 23). Below the subscription clause the subscribers to the Memorandum should write in his own handwriting his full name and father's, or husband's full name in block letters, full address, occupation, e.g.,'business executive, engineer, housewife, etc. and number of equity shares taken and then put his or her signatures in the column meant for signature. Similarly at the end of the Articles Of Association the subscriber should write in his own handwriting : his full name and father's full name in block letters, full address, occupation. The signatures of the subscribers to the Memorandum and the Article of Association should be witnessed by one person preferably by the person representing the subscribers, for registration of the proposed company before the Registrar of Companies. Under column 'Total number of equity shares' write the total of the shares taken by the subscribers e.g., 20 (Twenty) only. Mention date e.g. 5th day of August, 1996. Place-e.g. , 'New Delhi'.
# With the stamped copy, one spare copy each of the Memorandum and Articles of Association of the proposed company.
# Original copy of the letter of the Registrar of Companies intimating the availability of name.
# Form No. 18 - Situation of registered office of the proposed company.
# Form No. 29-Consent to act as a director etc. Dates on the consent Form and the undertaking letters should be the same as is mentioned in the Memorandum of Association signed by the director himself. A private company and a wholly-owned Government company are not required to file Form No. 29.
# Form No. 32 (in duplicate). Particulars of proposed, directors, manager or secretary.
# Power of attorney duly typed on a non-judicial stamp paper of the requisite value. The stamp paper should be purchased in the name of the persons signing the authority.
# No objection letter from the persons whose name has been given in application for availability of name in Form No. 1-A as promoters/directors but are not interested at a later stage should be obtained filed with the Registrar at the time of submitting documents, for registration
# The agreements, if any, which the company proposes to enter with any individual for, appointment as managing or whole-time director or manager are also to be filed.

Fee payable
Cash or a bank draft/ pay order treasury challan should be drawn in the name of the Registrar of Companies of the State in which the Company is proposed to be registered as per Schedule X.
Reporting Requirements

Annual Accounts
The Indian company law does not prescribe the books of accounts required to be maintained by a company. It, however, provides that the same should be kept on accrual basis and according to the double entry system of accounting and should be such as may be necessary to give a true and fair state of affairs of the company.
The Indian company law requires every company to maintain proper books of account with respect to the following:
# All sums of money received and expended and the matters in respect of which the receipt and expenditure take place
# All sales and purchases of goods by the company
# The assets and liabilities of the company
# In case of companies engaged in manufacturing, processing, mining etc, such particulars relating to utilization of material or labour or other items of cost.
The first annual accounts of a newly incorporated company should be drawn from the date of its incorporation upto to the day not preceding the AGM date by more than 9 months. Thereafter, the accounts should be drawn from date of last account upto the day not preceding the AGM date by more than 6 months subject to the extension of the time limit in certain cases. The accounts of the company must relate to a financial year (comprising of 12 months) but must not exceed 15 months. The company can obtain an extension of the accounting period to the extent of 18 months by seeking a prior permission from the ROC.
The annual accounts must be filed with the ROC within 30 days from the date on which the Annual General Meeting (AGM) of the company was held or where the AGM is not held, then within 30 days of the last date on which the AGM was required to be held.
Books of accounts to be kept by company
Every company is required to maintain proper books of account with respect to all sums of money received and expended, all sales and purchases of goods, the assets and liabilities. Central Government may also specifically require the maintenance of certain additional particulars with respect to certain classes of Companies. The books of account relating to eight years immediately preceding the current year together with supporting vouchers are required to be preserved in good order. Every profit and loss account and balance sheet of the company (together referred to as financial statements) is required to comply with the accounting standards issued by the Institute of Chartered Accountants of India. Any deviations from the accounting standards, including the reasons and consequent financial effect, is required to be disclosed in the financial statements.
The responsibility for the preparation of financial statements on a going concern basis is that of the management. The management is also responsible for selection and consistent application of appropriate accounting policies, including implementation of applicable accounting standards along with proper explanation relating to any material departures from those accounting standards. The management is also responsible for making judgements and estimates that are reasonable and prudent so as to give a true and fair view of the state of affairs of the entity at the end of the financial year and of the profit or loss of the entity for that period.
Annual Return
Every company having a share capital is required to file an annual return with the ROC within 60 days from the date on which the AGM of the company was held or where the AGM is not held, then within 60 days of the last date on which the AGM was required to be held.
Certain Accounting related issues
Depreciation
The company law in India permits the use of depreciation rates according to the nature of the classes of assets. Assets can be depreciated either on the basis of straight-line method (based on the estimated life of the asset) or on the basis of reducing balance method. The law prescribes the minimum rates of depreciation. A company may, however, provide for a higher rate of depreciation, based on a bonafide technological evaluation of the asset. Adequate disclosure in the annual accounts must be made in this regard.
Dividend
There is no limit on the rate of dividend but there are certain conditions prescribed with regard to computation of profits that can be distributed as dividend. Generally, no dividend can be paid for any financial year except out of the profits of that year after making an adequate provision for depreciation subject to certain conditions.
Dividends may also be distributed out of accumulated profits.
Repatriation of profits
A company has to retain a maximum of 10% of the profits as reserves before the declaration of dividends. These reserves, inter alia, can be subsequently converted into equity by way of issue of bonus shares. Dividends are freely repatriable once the investment approval is granted.
Imposition of taxes
Currently, domestic companies are taxable at the rate of 35.875% (inclusive of surcharge of 2.5%) on its taxable income. Foreign companies are taxed at a marginally higher rate of 41% (including surcharge of 2.5%). However, in case where the income tax liability of the company under the provisions of the domestic tax laws works out to less than 7.5% of the book profits (derived after making the necessary adjustments), a Minimum Alternate Tax of 7.6875% (including a surcharge of 2.5%) on the book profits, would be payable. Domestic companies are required to pay a dividend distribution tax of 12.8125% (including surcharge of 2.5%) on the dividends distributed during the year.
Companies are required to withhold tax under the domestic law from certain payments including salaries paid to employees, interest, professional fee, payments to contractors, commission, winnings from games / lottery / horse races etc. Moreover, taxes have to be withheld from all payments made to non-residents at the lower of rates specified under the domestic law or under the applicable tax treaty, if any.
Penalty

# Imprisonment up to two years and fine
# Person liable for default
# Person signing the declaration.
Download Company law Forms:
# Form no.1: Declaration of compliance with the requirements of the Companies Act, 1956 on application for registration of a company
# Form no: 18: Notice of the situation / change of situation of registered office
# Form no 29: Consent to act as director of a company and/or undertaking to take and pay for qualification shares [pursuant to section 264(2)/266(I)(a) & 266(1) (b) (iii)]
# Form no 32: Particulars of appointment of directors and manager and changes among them [Pursuant to section 303(2)]

Tuesday, November 28, 2006

ALL ABOUT CHEMISTRY

















Chemistry (from Greek χημεία khemeia[1] meaning "alchemy") is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals. Chemistry deals with the composition and statistical properties of such structures, as well as their transformations and interactions to become materials encountered in everyday life. Chemistry also deals with understanding the properties and interactions of individual atoms with the purpose of applying that knowledge at the macroscopic level. According to modern chemistry, the physical properties of materials are generally determined by their structure at the atomic scale, which is itself defined by interatomic forces.
Introduction
Chemistry is often called the "central science" because it connects other sciences, such as physics, material science, nanotechnology, biology, pharmacy, medicine, bioinformatics, and geology.[2] These connections are formed through various sub-disciplines that utilize concepts from multiple scientific disciplines. For example, physical chemistry involves applying the principles of physics to materials at the atomic and molecular level.
Chemistry pertains to the interactions of matter. These interactions may be between two material substances or between matter and energy, especially in conjunction with the First Law of Thermodynamics. Traditional chemistry involves interactions between substances in chemical reactions, where one or more substances become one or more other substances. Sometimes these reactions are driven by energetic (enthalpic) considerations, such as when two highly energetic substances such as elemental hydrogen and oxygen react to form the less energetic substance water. Chemical reactions may be facilitated by a catalyst, which is generally another chemical substance present within the reaction media but unconsumed (such as sulfuric acid catalyzing the electrolysis of water) or a non-material phenomenon (such as electromagnetic radiation in photochemical reactions). Traditional chemistry also deals with the analysis of chemicals both in and apart from a reaction, as in spectroscopy.
All ordinary matter consists of atoms or the subatomic components that make up atoms; protons, electrons and neutrons. Atoms may be combined to produce more complex forms of matter such as ions, molecules or crystals. The structure of the world we commonly experience and the properties of the matter we commonly interact with are determined by properties of chemical substances and their interactions. Steel is harder than iron because its atoms are bound together in a more rigid crystalline lattice. Wood burns or undergoes rapid oxidation because it can react spontaneously with oxygen in a chemical reaction above a certain temperature.
Substances tend to be classified in terms of their energy or phase as well as their chemical compositions. The three phases of matter at low energy are Solid, Liquid and Gas. Solids have fixed structures at room temperature which can resist gravity and other weak forces attempting to rearrange them, due to their tight bonds. Liquids have limited bonds, with no structure and flow with gravity. Gases have no bonds and act as free particles. Another way to view the three phases is by volume and shape: roughly speaking, solids have fixed volume and shape, liquids have fixed volume but no fixed shape, and gases have neither fixed volume nor fixed shape.
Water (H2O) is a liquid at room temperature because its molecules are bound by intermolecular forces called Hydrogen bonds. Hydrogen sulfide (H2S) on the other hand is a gas at room temperature and standard pressure, as its molecules are bound by weaker dipole-dipole interactions. The hydrogen bonds in water have enough energy to keep the water molecules from separating from each other but not from sliding around, making it a liquid at temperatures between 0 °C and 100 °C at sea level. Lowering the temperature or energy further, allows for a tighter organization to form, creating a solid, and releasing energy. Increasing the energy (see heat of fusion) will melt the ice although the temperature will not change until all the ice is melted. Increasing the temperature of the water will eventually cause boiling (see heat of vaporization) when there is enough energy to overcome the polar attractions between individual water molecules (100 °C at 1 atmosphere of pressure), allowing the H2O molecules to disperse enough to be a gas. Note that in each case there is energy required to overcome the intermolecular attractions and thus allow the molecules to move away from each other.
Scientists who study chemistry are known as chemists. Most chemists specialize in one or more sub-disciplines. The chemistry taught at the high school or early college level is often called "general chemistry" and is intended to be an introduction to a wide variety of fundamental concepts and to give the student the tools to continue on to more advanced subjects. Many concepts presented at this level are often incomplete and technically inaccurate, yet they are of extraordinary utility. Chemists regularly use these simple, elegant tools and explanations in their work because they have been proven to accurately model a very wide array of chemical reactivity, are generally sufficient, and more precise solutions may be prohibitively difficult to obtain.
The science of chemistry is historically a recent development but has its roots in alchemy which has been practiced for millennia throughout the world. The word chemistry is directly derived from the word alchemy; however, the etymology of alchemy is unclear (see alchemy).
History of chemistry
The roots of chemistry can be traced to the phenomenon of burning. Fire was a mystical force that transformed one substance into another and thus was of primary interest to mankind. It was fire that led to the discovery of iron and glass. After gold was discovered and became a precious metal, many people were interested to find a method that could convert other substances into gold. This led to the protoscience called Alchemy. Alchemy was practiced by many cultures throughout history and often contained a mixture of philosophy, mysticism, and protoscience (see Alchemy).
Alchemists discovered many chemical processes that led to the development of modern chemistry. As history progressed the more notable alchemists (esp. Geber and Paracelsus) evolved alchemy away from philosophy and mysticism and developed more systematic and scientific approaches. The first alchemist considered to apply the scientific method to alchemy and to distinguish chemistry from alchemy was Robert Boyle (1627–1691); however, chemistry as we know it today was invented by Antoine Lavoisier with his law of Conservation of mass in 1783. The discoveries of the chemical elements has a long history culminating in the creation of the periodic table of the chemical elements by Dmitri Mendeleyev.
The Nobel Prize in Chemistry created in 1901 gives an excellent overview of chemical discovery in the past 100 years. In the early part of the 20th century the subatomic nature of atoms were revealed and the science of quantum mechanics began to explain the physical nature of the chemical bond. By the mid 20th century chemistry had developed to the point of being able to understand and predict aspects of biology spawning the field of biochemistry.
The chemical industry represents an important economic activity. The global top 50 chemical producers in 2004 had sales of 587 billion US dollars with a profit margin of 8.1% and research and development spending of 2.1% of total chemical sales.[3]
Chemistry typically is divided into several major sub-disciplines. There are also several main cross-disciplinary and more specialized fields of chemistry.
• Analytical chemistry is the analysis of material samples to gain an understanding of their chemical composition and structure. Analytical chemistry incorporates standardized experimental methods in chemistry. These methods may be used in all subdisciplines of chemistry, excluding purely theoretical chemistry.
• Biochemistry is the study of the chemicals, chemical reactions and chemical interactions that take place in living organisms. Biochemistry and organic chemistry are closely related, as in medicinal chemistry or neurochemistry. Biochemistry is also associated with molecular biology and genetics.
• Inorganic chemistry is the study of the properties and reactions of inorganic compounds. The distinction between organic and inorganic disciplines is not absolute and there is much overlap, most importantly in the sub-discipline of organometallic chemistry.
• Organic chemistry is the study of the structure, properties, composition, mechanisms, and reactions of organic compounds. An organic compound is defined as any compound based on a carbon skeleton.
• Physical chemistry is the study of the physical and fundamental basis of chemical systems and processes. In particular, the energetics and dynamics of such systems and processes are of interest to physical chemists. Important areas of study include chemical thermodynamics, chemical kinetics, electrochemistry, statistical mechanics, and spectroscopy. Physical chemistry has large overlap with molecular physics. Physical chemistry involves the use of calculus in deriving equations. It is usually associated with quantum chemistry and theoretical chemistry.
• Theoretical chemistry is the study of chemistry via fundamental theoretical reasoning (usually within mathematics or physics). In particular the application of quantum mechanics to chemistry is called quantum chemistry. Since the end of the Second World War, the development of computers has allowed a systematic development of computational chemistry, which is the art of developing and applying computer programs for solving chemical problems. Theoretical chemistry has large overlap with (theoretical and experimental) condensed matter physics and molecular physics. Essentially from reductionism theoretical chemistry is just physics, just like fundamental biology is just chemistry and physics.
• Nuclear chemistry is the study of how subatomic particles come together and make nuclei. Modern Transmutation is a large component of nuclear chemistry, and the table of nuclides is an important result and tool for this field.
Other fields include Astrochemistry, Atmospheric chemistry, Chemical Engineering, Chemo-informatics, Electrochemistry, Environmental chemistry, Flow chemistry, Geochemistry, Green chemistry, History of chemistry, Materials science, Medicinal chemistry, Molecular Biology, Molecular genetics, Nanotechnology, Organometallic chemistry, Petrochemistry, Pharmacology, Photochemistry, Phytochemistry, Polymer chemistry, Solid-state chemistry, Sonochemistry, Supramolecular chemistry, Surface chemistry, and Thermochemistry.
Fundamental concepts
Nomenclature
Nomenclature refers to the system for naming chemical compounds. There are well-defined systems in place for naming chemical species. Organic compounds are named according to the organic nomenclature system. Inorganic compounds are named according to the inorganic nomenclature system.
Atoms
An atom is a collection of matter consisting of a positively charged core (the atomic nucleus) which contains protons and neutrons, and which maintains a number of electrons to balance the positive charge in the nucleus.
Elements
An element is a class of atoms which have the same number of protons in the nucleus. This number is known as the atomic number of the element. For example, all atoms with 6 protons in their nuclei are atoms of the chemical element carbon, and all atoms with 92 protons in their nuclei are atoms of the element uranium.
The most convenient presentation of the chemical elements is in the periodic table of the chemical elements, which groups elements by atomic number. Due to its ingenious arrangement, groups, or columns, and periods, or rows, of elements in the table either share several chemical properties, or follow a certain trend in characteristics such as atomic radius, electronegativity, electron affinity, and etc. Lists of the elements by name, by symbol, and by atomic number are also available. In addition, several isotopes of an element may exist.
Ions
An ion is a charged species, or an atom or a molecule that has lost or gained one or more electrons. Positively charged cations (e.g. sodium cation Na+) and negatively charged anions (e.g. chloride Cl−) can form neutral salts (e.g. sodium chloride NaCl). Examples of polyatomic ions that do not split up during acid-base reactions are hydroxide (OH−) and phosphate (PO43−).
Compounds
A compound is a substance with a fixed ratio of chemical elements which determines the composition, and a particular organization which determines chemical properties. For example, water is a compound containing hydrogen and oxygen in the ratio of two to one, with the oxygen between the hydrogens, and an angle of 104.5° between them. Compounds are formed and interconverted by chemical reactions.
Molecules
A molecule is the smallest indivisible portion of a pure compound or element that retains a set of unique chemical properties.
Substance
A chemical substance can be an element, compound or a mixture of compounds, elements or compounds and elements. Most of the matter we encounter in our daily life are one or another kind of mixtures, e.g. air, alloys, biomass etc.
Chemical bond
A chemical bond is the multipole balance between the positive charges in the nuclei and the negative charges oscillating about them. More than simple attraction and repulsion, the energies and distributions characterize the availability of an electron to bond to another atom. These potentials create the interactions which holds together atoms in molecules or crystals. In many simple compounds, Valence Bond Theory, the Valence Shell Electron Pair Repulsion model (VSEPR), and the concept of oxidation number can be used to predict molecular structure and composition. Similarly, theories from classical physics can be used to predict many ionic structures. With more complicated compounds, such as metal complexes, valence bond theory fails and alternative approaches, primarily based on principles of quantum chemistry such as the molecular orbital theory, are necessary. See diagram on electronic orbitals.
States of matter
phase is a set of states of a chemical system that have similar bulk structural properties, over a range of conditions, such as pressure or temperature. Physical properties, such as density and refractive index tend to fall within values characteristic of the phase. The phase of matter is defined by the phase transition, which is when energy put into or taken out of the system goes into rearranging the structure of the system, instead of changing the bulk conditions.
Sometimes the distinction between phases can be continuous instead of having a discrete boundary, in this case the matter is considered to be in a supercritical state. When three states meet based on the conditions, it is known as a triple point and since this is invariant, it is a convenient way to define a set of conditions.
The most familiar examples of phases are solids, liquids, and gases. Less familiar phases include plasmas, Bose-Einstein condensates and fermionic condensates and the paramagnetic and ferromagnetic phases of magnetic materials. Even the familiar ice has many different phases, depending on the pressure and temperature of the system. While most familiar phases deal with three-dimensional systems, it is also possible to define analogs in two-dimensional systems, which has received attention for its relevance to systems in biology.
Chemical reactions
A Chemical reaction is a process that results in the interconversion of chemical substances. Such reactions can result in molecules attaching to each other to form larger molecules, molecules breaking apart to form two or more smaller molecules, or rearrangement of atoms within or across molecules. Chemical reactions usually involve the making or breaking of chemical bonds. For example, substances that react with oxygen to produce other substances are said to undergo oxidation; similarly a group of substances called acids or alkalis can react with one another to neutralize each other's effect, a phenomenon known as neutralization. Substances can also be dissociated or synthesized from other substances by various different chemical processes.
Quantum chemistry
Quantum chemistry mathematically describes the fundamental behavior of matter at the molecular scale. It is, in principle, possible to describe all chemical systems using this theory. In practice, only the simplest chemical systems may realistically be investigated in purely quantum mechanical terms, and approximations must be made for most practical purposes (e.g., Hartree-Fock, post Hartree-Fock or Density functional theory, see computational chemistry for more details). Hence a detailed understanding of quantum mechanics is not necessary for most chemistry, as the important implications of the theory (principally the orbital approximation) can be understood and applied in simpler terms.
In quantum mechanics (several applications in computational chemistry and quantum chemistry), the Hamiltonian, or the physical state, of a particle can be expressed as the sum of two operators, one corresponding to kinetic energy and the other to potential energy. The Hamiltonian in the Schrödinger wave equation used in quantum chemistry does not contain terms for the spin of the electron.
Solutions of the Schrödinger equation for the hydrogen atom gives the form of the wave function for atomic orbitals, and the relative energy of say the 1s,2s,2p and 3s orbitals. The orbital approximation can be used to understand the other atoms e.g. helium, lithium and carbon.
Chemical Laws
The most fundamental concept in chemistry is the law of conservation of mass, which states that there is no detectable change in the quantity of matter during an ordinary chemical reaction. Modern physics shows that it is actually energy that is conserved, and that energy and mass are related; a concept which becomes important in nuclear chemistry. Conservation of energy leads to the important concepts of equilibrium, thermodynamics, and kinetics.
Further laws of chemistry elaborate on the law of conservation of mass. Joseph Proust's law of definite composition says that pure chemicals are composed of elements in a definite formulation; we now know that the structural arrangement of these elements is also important.
Dalton's law of multiple proportions says that these chemicals will present themselves in proportions that are small whole numbers (i.e. 1:2 O:H in water); although in many systems (notably biomacromolecules and minerals) the ratios tend to require large numbers, and are frequently represented as a fraction. Such compounds are known as non-stoichiometric compounds
Interpersonal chemistry
In the fields of sociology, behavioral psychology, and evolutionary psychology, with specific reference to intimate relationships or romantic relationships, interpersonal chemistry is a reaction between two people or the spontaneous reaction of two people to each other, especially a mutual sense of attraction or understanding.[4] In a colloquial sense, it is often intuited that people can have either good chemistry or bad chemistry together. Other related terms are team chemistry, a phrase often used in sports, and business chemistry, as between two companies.[5] Recent developments in neurochemistry have begun to shed light on the nature of the "chemistry of love", in terms of measurable changes neurotransmitters such as oxytocin, serotonin, and dopamine.
Etymology
The word chemistry comes from the earlier study of alchemy, which is basically the quest to make gold from earthen starting materials. As to the origin of the word “alchemy” the question is a debatable one; it certainly has Greek origins, and some, following E. Wallis Budge, have also asserted Egyptian origins. Alchemy, generally, derives from the old French alkemie; and the Arabic al-kimia: "the art of transformation." The Arabs borrowed the word “kimia” from the Greeks when they conquered Alexandria in the year 642 AD.

Saturday, November 25, 2006

FUNGAL DIVERSITY AND LIFE CYCLE

INTRODUCTION: The fungal functional type is comprised of sessile heterotrophs with cell walls. Rather than ingesting food as animals do, fungal organisms absorb food across the cell wall. The assemblage of organisms termed fungi are classified into two general categories. First, are the true fungi (Kingdom Fungi) which evolved from motile, aquatic protozoa that are also ancestors to the animal kingdom. True fungi first evolved as the chytrids (Phylum Chytridiomycota) who produce an enlarged globular cell from which numerous filaments grow into the food source. Chytrids produce motile spores and gametes, and the vegetative cells are ceonocytic (many nuclei float around in one big cell). Chytrids gave rise to the Zygomycetes (Phylum Zygomycota), which produce no motile cells but form ceonocytic hyphae. From the Zygomycetes, the advanced fungi arose and in time formed the Phylum Dikaryomycota. Organisms in the Dikaryomycota produce hyphae comprised of individual nucleated cells separated by walls (septate hyphae) with each cell having two haploid nuclei in what is called an N + N configuration. The two main groups of dikaryotic fungi are the ascomycetes (sac-forming fungi) and the basidiomycetes (club-forming fungi). The majority of fungi affecting humans are ascomycetes and basidiomycetes.
The second category of fungal organisms is the pseudofungi, made up of various unrelated protista groups. The pseudofungi were formerly classified into the catch-all kingdom Protista but have recently been reclassified into more-specific kingdoms that reflect genetic relationships. Important pseudofungi are the Oomycetes (egg fungi and water molds), and the slime molds. Oomycetes are closely related to the stramenopilous algae - the brown algae, golden-brown algae and diatoms of the Kingdom Stramenopila. The close relationship between the oomycetes and the brown algae is evident in that both have cellulose walls, and they share the same type of flagella. Oomycetes descend from algae that lost their chloroplasts, and hence have adopted a heterotrophic life form. Oomycetes also produce filamentous hyphae to better absorb nutrients from the food source. Because they have no relationship with the chytrids, it is clear that the oomycetes and chytridiomycetes independently evolved the mycelial life form.
Slime molds evolved from various ancient protozoa and have little genetic affinity to other fungi or algae groups. They are animal-like in that they ingest food early in the life-cycle, but are fungal-like in that they produce walled sporangia and spores.
In today’s lab, you will have a chance to examine the diversity of both false and true fungi. The lab will begin with the false fungi and then follow an evolutionary sequence through the true fungi. Many specimens illustrate important reproductive phases in the life-cycles of these organisms. You should examine these carefully because reproductive features are important to understanding and distinguishing the various groups of fungi.
Although not required, we urge you to draw and label the specimens you examine. Our experience has been that drawings with appropriate labels are the best way to learn the features emphasized in lab and lecture. Drawings are also an excellent study tool to refresh your memory just prior to the exam
PART I: THE PSEUDOFUNGI
A) Slime molds (Kingdoms Myxomycota and Dictyosteliomycota): Slime molds are largely saprophytic and are typically found on decaying wood in moist forests. During the vegetative phase of the life cycle (see figure 16-6 on page 353 of your text), they begin life as independent amoebae, ingesting microscopic bits of organic debris. The free-living amoebae eventually swarm together to produce a multicellular blob called a plasmodium. After a while, the plasmodium forms cellulose walls around the nuclei and produces sporangia (or fructifications). The sporangia release large numbers of air-borne spores which germinate in the presence of water to form free-living amoebae, thus completing the life cycle. Slime molds defy simple categorization. They are animal-like in that they ingest food during the amoeboid- and plasmodial-phase. They are plant-like in their formation of cell walls and sporangia during reproduction. Because of the cell-walls formed during the reproductive phase they are considered fungal in nature. There are two major types of slime molds:
A) the Myxomycota are the acellular, or true plasmodial slime modes: The plasmodium stage of this group is made up of large blobs of ceonocytic protoplasm with many nuclei inside.
B) the Dictyosteliomycota are the cellular clime molds, where the plasmodium is made of individual cells separated by membranes (but not cell walls).
Observations on Display: Fruiting bodies of slime molds are readily found in Ontario forests in the autumn. Some will be on display for you to examine, along with a diagram of the life cycle.
B) Oomycetes: the water molds, or egg fungi (Kingdom Stramenopila)
Oomycetes are characterized by the formation of large egg-bearing cells on the tips of specialized hyphae termed oogonia (see figure 17-4 on page 374 of your text). Large, non-motile eggs form inside the oogonia and are fertilized by male-like hyphae termed antheridia. The antheridia grow into the egg and deposit the male gametes, which then fuse with the egg to form a zygote, termed the oospore. The oospore undergoes mitosis and forms a sporangia. The spores that are produced disperse to infect leaves, seedlings, fish and dead organisms.
Oomycetes are important saprophytes in aquatic habitats. In terrestrial habitats, they are generally parasitic. Important diseases caused by water molds are downy mildews (Peronospora), potato late blight (Phytophthora infestans), and damping off disease (Pythium spp.). We will examine three species, Achlya, a saprophytic water mold; Albugo candida, the white rust of mustard plants and Phytophthora infestans.
Examine the following cultures with the dissecting microscope:
1. Achlya whole mounts: Achlya is a water mold that grows on organic debris in lakes and rivers. It forms floating mycelia mats arising from the food material, and in these mats sexual reproduction occurs. On your bench are prepared slides for you to examine with the light microscope. Focus on the blue-green material in the center of the slide. This is a hyphal mat with oogonia.
Observe the large conspicuous oogonia within the mycelium. Inside the oogonia you can see zygotes (oospores), that will later divide to form sporangia. Examine the oogonia closely to see if additional hyphae are attached to it. These would be antheridia, which present the sperm nucleus to the egg cells
within the oogonia. Note the properties of the vegetative hyphae. Do you see cross walls, or are the cells continous within a filament?
2. Phytophthora infestans: This organism causes potato late blight, one of the worst crop diseases in the history of humanity. In the 1840’s, Phytophthora infestans was introduced to Europe from Peru. It rapidly spread across the continent, destroying much of the potato crop. In Ireland, peasants were particularly dependent on the potato for survival, and the crop losses in 1845-1848 killed millions of Irish and forced the migration of millions more to North America. In continental Europe, the loss of the potato crop led to widespread economic failure and social revolt. Many of the radical worker movements that would later influence world history, such as Marxism-Leninism, arose in the wake of the food crisis caused by the Phytophthora outbreak.
Examine the Phytophthora slide prepared fresh from a culture stained with cotton blue. Identify the round oogonia in the slide and examine the hyphae for cross walls between the cells. Are there any oospores within the Oogonia? Can you see any antheridial hyphae attached to the oogonia? If you do, show other students in your group.
3. Albugo candida (White Rust of Mustards): Albugo infects plants of the mustard family, forming white pustules on the leaves. These pustules are comprised of many asexual conidiospores bursting through the plants epidermis. Inside the plant, fungal hyphae form oogonia and antheridia, which will mate and form oospores. The oospores develop sporangia which disperse genetically-distinct spores. The two prepared slides show the extent of the infection by the parasitic white rust fungus.
Examine the prepared cross section showing Albugo conidiaspores bursting through the epidermis of a mustard fruit. Note the strings of conidiospores forming under the epidermis. The bulge formed by the mass of conidia produce the rust pustule. Upon rupturing, the conidiospores are released on the wind to start a series of new infections.
Examine the prepared slide of the Albugo sexual organs (oogonia and antheridia). The oogonia are evident as dense, red-staining circles among the cells of the leaf tissue.
Notes and Drawings:
PART II: THE TRUE FUNGI (KINGDOM FUNGI)
We have assembled a range of specimens from the Kingdom Fungi, and they are arranged for you to examine beginning with the most primitive (the Chytrids) and then progressing through the Zygomycetes to the Ascomycetes and Basidiomycetes.
A. CHYTRIDIOMYCOTA (The Chytrids):
Chytrids are mainly aquatic or parasitic. They are important decomposers of pollen, dead insects and seeds that fall into ponds and rivers. Others are parasites of algae, higher fungi, mosquitoes, rotifers, and water molds. The general body plan is to form a large, central ceonocytic globule that either directly invades the body of the host, or produces diminutive hyphae termed rhizomycelium, which invade the surface cells of the host. The rhizomycelium grows into the food source and absorbs nutrients across the chitenous cell wall.
Chytrids are difficult to maintain in culture and have to be baited from natural sources. We have purchased slides showing a common parasitic chytrid, Synchytrium, invading a plant host, and have prepared a fresh culture of chytrids on snake skin. Chytrids are important decomposers of animal epithelial tissue in aquatic habitats. To capture them, we have placed strips of snake skin in pond water. Chytrid spores swim to the snake skin, and then germinate on the skin, forming a simple globular body with rhizomycelium.
Examine:
Synchytrium: Examine the prepared slide of Synchytrium that has infected either leaves or potato tubers. Note the simple globular body (the sorus) of the chytrid embedded in the tissue of the plant. Some of the globules may have matured into sporangia, and you may see spores inside.
Chytrids on snakeskin: In the dissecting scope, you can see the rhizomycelia extending from the snake skin, along with many protozoa. Note the pinhead-like cells within the mycelia. These are either the central globules from which multiple filaments of rhizomycelium arise, or they are sporangia.
In the light microscope, examine the globular cells and the hyphae growing away from them. The globular cell and rhizomycelium form the basic body plan of the saprophytic chytrids.
You will also see many tiny creatures swimming about the mycelium. Some of these may be zoospores released from sporangia. Examine the mycelium for any evidence of sporangia. Sporangia will be apparent as they will have only one hyphae attached to them.
B. ZYGOMYCOTA:
The Zygomycetes are important saprophytes, including species that are major decomposers of dung and food. Members of this group have a zygotic lifecycle (see figure 15-11 on page 316 of your text). The gametes are non-motile, and are born on the tips of specialized, fertile hyphae termed gametangia. The gametangia contain many haploid nuclei. In zygomycetes, the sexual act consists of two fertile hyphae growing towards each other. As they approach each other the ends of the hyphae form gametangia. The gametangia come in contact, after which the end walls disintegrate, releasing the haploid gamete nuclei into one common space. Pairs of haploid nuclei then fuse, creating many diploid nuclei.


The nucleate cell formed from the residuals of the two gametangia is termed a zygosporangium. Zygosporangia typically develop a thick wall that protects the diploid nuclei from harsh conditions, forming a many nucleate (ceonocytic) resting cell. Zygosporangia germinate when the diploid nuclei undergo meiosis to produce many new haploid nuclei. The haploid nuclei are walled off into distinct spores, which are released from a dispersal sporangium that grows out of the zygosporangium.
The most commonly encountered zygomycetes are the bread molds, which are important saprophytes that grow on carbohydrate-rich foods, including bread. The mycelium formed on the surface of the bread is a cottony mass that is initially white but soon darkens as the mycelium forms asexual sporanagia. Large numbers of mitospores are released, allowing the fungus to quickly spread.
Examine the following, first under the dissecting scope and then with the light microscope:
1. Zygorrhynchus moelleri: This mold growing on an agar plate shows the major stages of a typical Zygomycete life cycle. First examine the culture under the dissecting microscope, and then take a very small scraping of the agar with a dissecting needle or knife. Place this on a microscope slide, stain with the cotton blue stain on your bench, and examine at medium power with both phase contrast and normal visible light.
With the dissecting scope, examine the cottony matrix of the mycelium, and the sporangia rising above it, forming dark spheres on elongated stalks. These are mostly mitosporangia used in asexual reproduction. You may be able to see zygosporangia mixed in amongst the mycelium. They will be dark, barrel-shaped granules on the surface of the agar.
With the light microscope, observe the slide of agar, note the clear tubular nature of the hyphae and the absence of cross walls. Next observe any mitosporangia you may have opened while pressing down the cover slip.
Finally, observe the zygosporangia. These are dark, barrel-shaped structures with rough walls. Note the hyphae attached to the zygosprangia. These are the stalks of the gametangia, and are termed suspensors.
2. Rhizopus stolonifera: This is the common bread-mold, a regular feature of most pantries. We have provided you with a Petri plate of Rhizopus to examine. Note the following with the dissecting scope under high power:
Examine the mycelium and sporangia. You may be able to see elongated, horizontal hyphae connecting the sporangial stalks. Rhizopus spreads by these elongated hyphae, termed stolons (after the strawberry runners of the same name). Where stolons settle onto a food source, they produce anchoring hyphae that penetrate the food. Sporangia form above this contact point. This habit allows for rapid spread of Rhizopus over a loaf of bread. Typically, Zygomycetes reproduce asexually by mitospores when conditions are good, allowing for rapid spread over a new food source. They switch to sexual reproduction when the food is exhausted and conditions deteriorate.
3. Ungulate dung: We may display some moose or cow feces which may show a range of dung-zygomycetes, possibly including the hat-throwing fungus Pilobus. If anything of interest appears to be present, examine it with the dissecting scope and note the nature of the sporangia.


C. THE DIKARYOMYCOTA
The dikaryomycota were formerly classified as the phyla Ascomycota and Basiodiomycota (for example, see chapter 15 in your text), but recent advances in the systematic understanding have led to the merging of these two groups in a single phylum of higher fungi, the Dikaryomycota, with the ascomycetes and basiodiomycetes being separated into subphyla termed Ascomycotina and Basiodiomycotina. We will focus on these two groups.
The common feature of these groups is the formation of dikaryotic hyphae. The dikaryon arises when the protoplast of haploid hyphae fuse (they undergo plasmogamy). The nuclei do not initially fuse, and the resulting mycelium is made up of cells that are dikaryotic, or in the N + N state. Fusion of the two nuclei occurs in the fruiting body of the fungus, forming a diploid cell that immediately undergoes meiosis and mitosis to produce four to eight spores. The spores are released from sporangia formed in the fruiting body. In the ascomycetes, eight spores are released from sacs termed asci (singular is ascus, from the Latin word for sac). In the basiodiomycetes, the spores are formed on the end of a club-like sporangia termed a basidium (from the Latin word for club). The fruiting bodies of each fungus are termed an ascocarp (ascoma in your text), and the basidiocarp (basidioma in your text). The mushroom cap is a basidiocarp.
We have a number of specimens for you to examine today from each subphylum.
1. Subphyllum Ascomycotina
a. Unicellular forms: the yeasts: These are single-celled fungi that typically live within the food medium. Most are saprophytic, although some can become parasitic. The yeast fungus Candida albicans is an important pathogen in humans, forming diaper-rash, vaginal and urethral tract infections, and the potentially deadly sexually-transmitted disease candidiasis. The common yeast Saccharomyces cerviseae is the yeast of baking, brewing and enology (wine making). This yeast is preferred in fermentations as it rapidly grows, produces pleasant as opposed to noxious or toxic waste-products, and is tolerant of high (>10%) concentrations of ethanol.
Saccharomyces cereviseae: The common brewers yeast is growing on agar. Take a very small portion off the culture and smear into a drop of water on a microscope slide. Add a cover slip, and examine at low and then high power with the compound scope.
Look for budding cells amongst the large numbers of indistinct single yeast cells. These are apparent from the blob-like cellular extensions, termed buds that arise from mature yeast cells. Rather than simply dividing in two as most algae and plant cells do, yeasts divide by extruding protoplasm into a bud. This extrusion is then encapsulated in a wall and split off to form a new independent cell.
Occasionally, you may see some yeast forming asci: Yeasts live in both a haploid and diploid state. When conditions are harsh, two diploid yeast nuclei merge to form a zygote, which then undergoes meiosis to produce a four celled sac, the ascus. The ascus splits open to release the four cells, which then bud to start a new population of yeast cells. You may be able to see four-celled asci floating among the many cells in your slide. If so, show your classmates.

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b. Filamentous Ascomycetes: Multicellular ascomycetes produce hyphae and mycelium, and form ascocarps. Three types of ascocarps are produced by these fungi, cleistothecia (enclosed spheres), perithecia (vase-like) and apothecia (cup shaped). You should examine examples of each.
b.1 Cleistothecial species:
i. Powdery mildew (Uncinula spp.): Powdery mildews are common pathogenic fungi that infect leaves, forming a powdery mycelium on the surface. Powdery mildews reproduce asexually by forming chains of spores (conidiospores) on special hyphae termed conidophores. During sexual reproduction, they form a simple enclosed ascocarp, the cleistothecia. Cleistothecia are completely enclosed, with no opening for the developing spores to escape. When mature, the ascocarp wall ruptures, allowing enclosed asci with their ascospores to spill out and disperse. Often, cleistothecia have barbs and hooks, which can help disperse the entire ascocarp by clinging onto the fur of passing animals.
Examine the following:
Dissecting scope: Scan across the leaf infected with Uncinula to note the powdery mycelium, with chains of conidia rising above it. Periodically, you will see a pepper grain-like object with multiple elongated hooks attached. This is the cleistothecia.
Light microscope: Scrape some cleistothecia onto a microscope slide and cover gently with a cover slip. Examine at low power. Next press of the cover slip to rupture the ascocarp and release the spores inside.
ii. Powdery mildew on leaves: We also have specimens of unknown powdery mildews collected on leaves from around Toronto. Examine these under the dissecting scope for cleistothecia and conidia.
b.2 Perithecial species: The perithecium is a vase-shaped ascocarp with a narrow, open neck. Inside are multiple asci with spores. When mature, the asci protrude from the neck of the perithecia and forcibly eject the spores into the air. Sordaria is a dung saprophyte that is closely related to Neurospora, the fungus that has become one of the leading model organisms in genetic research.
Examine:
Dissecting scope: Sordaria is growing on agar plates, and the perithecia can be seen as dark pepper-like grains mixed in a mass of conidia-forming hyphae. Examine the perithecia closely and note the pear-like shape of the ascocarp. Are any asci protruding from the perithecia?
Light microscope: Scoop some perithecia onto a slide, cover and examine at low-to medium power. Gently push on the cover slip to squash open the perithecia. Note any football-shaped spores and asci that emerge.
b.3. Apothecial species: The apothecium is an ascocarp where the asci are directly exposed to the air in a cup, dome or invaginated surface. The fungi are commonly called the saucer, or cup fungi, and they include many beautiful, brightly colored forest species. The delectable morel is an apothecial ascocarp. To demonstrate the apothecium structure and form, we have a set of prepared slides and live specimens from a number of species.

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i. Bispora centrina (Yellow-fairy cups – live specimens): These are wood decomposing fungi that form small, brightly yellow cup shaped apothecium. Examine the stick with the fairly cups closely. You may take the stick to you bench to examine with a dissecting scope. The asci are formed on the inner surface of the cup. Return the stick to the display area when finished as we have only a few specimens.
ii. Peziza (prepared slides): Peziza is a cup fungus that grows on wood and is similar in form to Bispora. A life cycle of Peziza is shown in Fig. 15-14 on page 318 of your textbook.
Examine the prepared cross sections of the Peziza ascocarp under medium power with your light microscope. You will note the sac-like structure of the ascus with 8 haploid spores inside. These arose from meiosis and one subsequent round of mitosis. Note the zone of fertile tissue where the asci form. Below this are fattened vegetative cells that form the support structure of the ascocarp.
b.4 Ascomycetes of special note
i. Claviceps purpurea (Ergot of Rye)
We have display specimens of rye shoots infected with Ergot, caused by the perithecia-forming ascomycete Claviceps purpurea. Claviveps is an example of an endo-parasite, a fungus that grows within the stem and leaves of grasses. The fungus retards growth, but does not kill the host plant. In many instances, toxins produced by the fungus deter herbivory, and so the grass host can actually show superior performance relative to a non-infected plant that is eaten. In the case of ergot, the toxin produced is lysergic acid amide, from which the hallucinogenic drug lysergic acid diethyamide (LSD) was derived.
Examine the infected rye and note the grain heads with enlarged, dark-colored protrusions extending out from the grass stalk. These are sclerotia, which occur where the fungus has completely infected a developing grain and replaced the grain with a tight mat of interwoven mycelium. As the growing season ends, the sclerotia fall to the ground and overwinter. In the spring, they produce perithecia and in turn, large numbers of spores that infect the new rye crop.
Sclerotia break free and mix with the rye grain at harvest. People eating rye contaminated with ergot sclerotia experience severe poisoning, called ergotism. Symptoms include wild hallucinations coupled with extreme burning sensations in the extremities. Constriction of minor veins is common, leading to limbs dying and falling off. The pain is severe, and a typical victim would scream in agony while madly hallucinating. Before modern science explained the cause, people in the past would interpret the symptoms as an attack of demons, and in regions affected by ergot outbreaks, the citizens often turned to extreme religious practices to exorcise the devil. Throughout history, witch hunts, new religious movements, and mass hysteria have been attributed to ergot outbreaks.
Today, ergot poisoning is rare, and rye grain is routinely screened to filter out the larger sclerotia. Sclerotia are now intentionally grown as a source of drugs to control internal bleeding, migraine headaches, and to alter mental states in psychiatric patients.
ii. Peach Brown Rot (Monilinia fructicola): Many ascomycetes are severe pathogens of fruit crops. One of the worst is Peach Brown rot, which stunts trees and destroys mature peaches, apricots, cherries and related fruit. Infected trees form cankers on the twigs and leaves. Conidia erupting from the cankers are dispersed to infect other trees by asexual means. Fruits are infected as they near maturity.

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After infection, lesions develop on the fruit and it prematurely rots, falls to the ground and dries to a mummified carcass. Peach mummies are completely infected with the mycelium and in this form, the fungus will overwinter. In the spring, the fungus in the mummy form apothecia, from which spores will be released in huge numbers to infect new trees.
Examine the Monilinia cultures on agar with the dissecting microscope and note the lemon-shaped conidiospores arising from the mycelium. You can examine these more closely by taking a small piece of agar and preparing it on a slide for examination with the light microscope.
iii. Penecillium: Many ascomycetes are saprophytes that infect food and building materials in the home. Some are also sources of important drugs, while other produce powerful carcinogens. Penicillium is one of the most common molds in the household pantry, where it infects bread, fruits and milk products. Penicllium species are also important in making strong-flavored cheeses such rouquefort, gorgonzola, chamenbert, brie and Danish Blue. The blue-green color is actually the reproductive conidia of the Penicillium mold. Pennicilium is also the source of penicillin, the antibiotic that prevents wall synthesis in gram negative bacteria.
Examine the culture with the dissecting scope and note the green-blue broom-like conidiospore masses rising above the mycelium. These masses give Penicillium molds their characteristic color. Take a sample and prepare a microscope slide of it. Examine the conidiophores with conidia under the compound microscope. Note the broom-like structure of the spore-bearing mass.
We also have some blue-cheese on display. Examine the Pennicilium colony through the dissecting scope and try to identify the sporangia.
iv. Aspergillus: Aspergillus species are common black-colored molds in the household environment. They are frequently found on bread, drywall, and grains. Many species produce aflotoxins, which are powerful carcinogens of the liver found in stored grains, peanuts and cereals, including corn flakes. It is unwise to eat foods contaminated with wild Aspergillus species as they likely contain aflotoxins. (For example, never eat wild peanuts, or musty old grain). Beneficial Aspergillus spp. are used to produce soy sauce, miso (fermented soy paste), and to ferment rice in an early step in sake production.
Examine with a dissecting scope the culture on the agar plate and note the fan-shaped mass of conidia arising above the mycelium. Next, examine a piece of the mycelium to see the bulbous conidiophore. The dark masses of conidia give this fungus its particular color and shape.
Take a small chunk of infected agar and prepare a slide of the sporangia for the light microscope. Examine the swollen top of the condiophores and the attached fan-shaped array of conidia.
2. The subphylum Basidiomycotina
The most familiar fungi are the basidiomycetes. The fruiting bodies of the basidiomycetes (the basidiocarp) are the recognizable features of species of mushrooms, toadstools, coral fungi, shelf fungi and tooth fungi. In each, the main body lives underground or in wood as a dispersed mycelium. Although all basidiomycetes reproduce by forming spores on club-shaped basidia, there are actually two main groups: the homobasidiomycetes and the heterbasidiomycetes. The homobasidiomycetes produce one type of spore, the basidiospore. The heterobasidiomycetes produce two types of spores

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during the sexual life cycle. We will focus on the homobasidiomycete life cycle as exemplified by the common food mushroom, Agaricus campestris. Heterobasidiomycetes are the pathogenic rusts and smuts.
a. Basidiomycete yeast (Rhodotorula ruba): Some basidiomycetes also have evolved the unicellular life form. A common basidiomycete yeast is the red yeast, Rhodotorula ruba, a contaminant of bathroom curtains, tile and grout. The pink scum in filthy bathtubs and showers is caused by Rhodotorula. (You may remember the battle between the Cat-in-the-Hat and pink bathroom scum).
Examine the red yeast culture on display. If time permits, you may prepare a microscope slide of the cells from the agar culture. Examine them for budding and basidia, which are distinguished by an elongated shape and horn-like points on one end of the cell.
b. Heterobasidiomycetes: The heterobasidiomycetes include the rust diseases of grasses, and smut diseases of maize. Other members of this group are wood decomposers such as the jelly fungi. We may have a jelly fungus in the wild mushroom display.
Examine the specimens of grasses infected with wheat rust (Puccinia graminis). Note the rust-colored pustules forming on the blades of the grass. These are where asexual spores are formed to allow for continued infection of healthy plants during the summer. Black pustules appear in the late-summer. These are where teliospores are formed. Teliospores are overwintering spores that form basidiospores in the spring.
If available, examine any corn smut (Ustilago maydis) that may be on display. Corn smuts attack developing corn kernels and produce large, grey-colored smutballs that are filled with dark spores. Immature smutballs are served as a delicacy in Latin American cuisines.
Rusts and smuts are virulent parasites of grain crops, with the potential to wipe out the production of an entire region in any given year. The primary means of preventing infestation is to breed crop cultivars that are resistant to rust infections. The rusts eventually evolve new ways to infect the cultivar, so government agencies are continuously breeding resistance into varieties to stay ahead of the rust capacity to re-evolve virulence. Should breeding efforts fall behind (for example, via cost-cutting measures by governments and agribusiness), major rust outbreaks could result, ruining grain crops and causing food prices to sky-rocket.
Notes:

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c. Homobasidiomycetes: the Mushrooms
We have fresh specimens of the common store-bought mushroom for examination, along with cultures of the inky cap mushroom, and a range of wild mushrooms from southern Ontario. To aid in examining fine detail, we have prepared slides showing cross sections of mushroom caps for you to examine under the light microscope. A detailed diagram of the life-cycle of the mushroom is presented in Figure 15-19 of your textbook (page 321).
c.1. The common food mushroom Agricus bisporus:
Examine a) the mycelium of the spawn blocks on display, b) the young button mushrooms and c) mature-spore producing mushrooms from the collection of fresh mushrooms provided.
i. Mycelial stage: sample mycelia of the mushroom spawn that is available. Stain with cotton blue and view with the light microscope under both normal light and phase contrast. Find some isolated hyphae and examine this under high power. Note the septate nature of the hyphae. This is one of the diagnostic features of the basidiomycetes.
Each cell contains two haploid nuclei in the N + N configuration. A key feature of Basidiomycetes is the presence of clamp connections, which form after cell division in order to keep the N + N dikaryotic configuration intact (see figure 15-21 in your text). Clamp connections may be visible along the end walls of the hyphal cells, forming bulges or loops around the septate wall.
ii. The mushroom button stage: The basidiocarp forms from tightly woven mycelia. Initially, the basidiocarp form a button, or egg stage. Cut open a button and examine a) the immature stalk (or stipe), b) the young, white to pink gills, and c) the developing cap which extends down over the stipe. With a razor blade, cut a thin slice of a gill, and look at the slice with the light microscope. Stain the gill with Melzer’s blue. You may be able to see developing basidia with miniature spores.
iii. The mature mushroom: Note the features of the basidiocarp structure. The main parts are a) a well developed stalk, termed the stipe. The cap, termed the pileus, and the gills, where the spore bearing tissues occur. The gills have turn chocolate brown as millions of spores mature. Cut a thin slide of the mature gill and examine for spores and horned basidia. Stain with the Melzers stain placed on your bench. You should be able to isolate one or two good basidia from the mass of tissue.
iv. Prepared slide of the mushroom cap: Examine under the light microscope the cross sections prepared of an Agaricus pileaus. The cross sections of gills clearly demonstrate the club shaped basidia arising from the zone of fertile tissue (the hymenium). Examine the basidia under high power and note how the spores are attached to the horn-like basidial tips (the sterigmata). The spores appear as party balloons taped to a club.
v. Spore prints: As the spores mature, they are released and drift into the air below the cap. If the cap is place over paper, the spores cannot disperse and settle onto the paper to form a print of the mushroom gills. Spore prints have been prepared for you to examine. Spore prints are often used to identify particular mushrooms, and they are an easy way to verify the color of the spores.

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c.2. The Inky-cap mushroom, Coprinus cinereus. We have displays of the Inky-cap mushroom for you to examine. The cultures show how the mushroom arises from the mycelium. Prepared slides are also available if you wish to examine the gill structure and the basidia of Corpinus.
The cap self-digests upon maturity forming a purple-ink colored mass of goo.
c.3. The oyster mushroom Pleurotus ostreatus: Oyster mushrooms are delightful edible mushrooms that grow on logs and decaying stumps. They produce white spores on short gills, and exhibit a large, fan-shaped pileus with a short stipe. They are now commonly cultivated and are available in many supermarkets.
Examine the oyster mushrooms for morphological structure, then thin slice a gill and examine for the basidia and white spores under the microscope.
c.4. The chanterelle (Chanterellus cineareus): Chanterelles are a wonderful delicacy that is prized for its gentle, buttery flavor. Unlike the gilled mushrooms, chanterelles form their basidia on gently folded tissue underneath a wavy pileus. Assuming we have these available, take a small piece of the pileaus of a chanterelle and examine for basidia and spores. What color are the spores?
c.6. The wild mushroom display: We have collected a variety of wild mushrooms for you to examine for variation in form. Examine each carefully, paying attention to the pileus, the stipe (if present) and where the spore bearing tissues are located. In many of the samples, gills are not present. Instead, the spores are produced on elongated tubes that form pores on the underside of the pileus, on teeth-like protrusions that hang below the pileus, on coral-like prongs, or on rumpled folds of tissue that resemble elbow skin. These traits distinguish the major families of mushroom-forming species. You may take some of the specimens and examine them under the dissecting scope in order to better see the pores, teeth or prongs of the spore-bearing tissue.
PART IV: LICHENS
Lichens are structures formed by close symbiotic relationships between an algae and a fungus. Both green and blue-green algae can serve as the algal symbiont, while the fungus is typically an ascomycete. Because the sexual stage of the lichen that is visible is that of the fungal partner (the mycobiont), the lichen is typically named after the fungus.
In the symbiosis, the algae provide carbohydrates from photosynthesis while the fungus shelters the algae and gathers water and nutrients. Lichens can completely desiccate with no harm to the organisms inside. Upon wetting they rapidly rehydrate and resume activity. This ability allows them to live in extremely harsh surfaces, such as the branches and trunks of trees, the sides of rocks, and bare ground in deserts. In the boreal zone, lichens are important ground covers on bare soil, fallen branches and the surface of rocks. They also are common as epiphytes on trees. In general, they grow extremely slow, reflecting the harsh conditions of the habitats they live in.
Lichens come in three general categories based on morphology. Examine the specimens displayed in the lab room.

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A. Foliose lichens: Lichens that exhibit a leafy shape are termed the foliose lichens. These are common in wetter habitats, for example, forest interiors in eastern Canada. Foliose lichens are important epiphytes growing on branches of standing trees.
B. Fructicose lichens: These lichens are shrubby in appearance, with many narrow, highly branched stem-like structures. Fructicose lichens are common in the boreal forest, forming dense ground covers in spruce forests. When dry, they are extremely flammable and can be used as a fire starter. They also help wildfires spread and thus contribute to some of the severe forest fires that occur every summer in Canada. Fructicose lichens are common on the sides of trees, and often hang from the bra nches in dense growths termed Witch’s hair, or Old Man’s Beard.
C. Crustose lichens: Crustose lichens occur in the most extreme terrestrial environments where life is possible. They grown on the sides of rocks, buildings and on bare soil, and are common in arid and polar deserts, including the dry valleys of Antarctica. Crustose lichens form brilliant yellow, orange, red and yellow-green colors on the rock, and are some of the most beautiful features in what are otherwise barren landscapes.
Study Guide: You should be familiar with the major categories of fungi and the names of the common species of yeast, store mushrooms, and major disease organisms displayed in the lab. You need to know the terms presented in bold font, and should recognize an organism well enough to classify it to phylum or where relevant, to subphylum. Know and understand the distinguishing characteristics of the major phyla presented in lab, as well as that of the ascomycetes and basidiomycetes.

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