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Gene Mutation

 

Any permanent change in the structure of DNA sequence which makes up a gene is called as gene mutation. The size of the mutation varies , it may either as small as a DNA or even large as a segment of the chromosome.

The mutation of the Gene occurs in two ways: 1. from a parent 2. acquired during the persons lifetime. Hereditary mutations or the germ line mutations are those which occur from the parents to the children. The mutation of this sort can be seen in the persons entire like in every cell in his/ her body.

The other are the new mutations which are occurred in the egg or the sperm cell or the mutation which occurs just after the fertilization process is complete. The genetic disorders can be best explained by the De novo mutations, however in this type of disorder there is no family history for this disorder involved.

The somatic (also known as acquired) mutations are the one which occur directly into the DNA of the individual cell. There is a possibility of DNA making copies of itself during cell division due to immense expose to the ultra violet radiations from the sun which result in number of changes in the individual’s life. The acquired mutations int he somatic can not be passed to the next generations.

Mutations can also occur in the single cell in the early period of embryo. During the division of the cells the individual has some cells with the mutation and some other without any genetic changes. This situations is referred as mosaicism.

Some of the changes in the genetic makeup of the cells are very rare to find, while on the other hand some changes are easily spotted. The Genetic changes which can be found in more than 1% of the population are known as polymorphisms. polymorphisms are resposbile for the differences like the color of the hair, blood type and the color of the eye. Usually, polymorphisms don’t have any negative effects which affects the health of an individual, however they may also cause number of variations which can develop certain disorders in the individual.

Posted in Genetics. Tagged with , , .

By admin
May 18, 2009

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Multifactorial Disorders

It is studied by researchers that a genetic component is responsible for most of the diseases and conditions in human beings. Some disorders like the cystic fibrosis or the sickle cell anemia are a result of mutations in a single gene. However, the cause of many other diseased conditions is very complex. Some of the common disorders like diabetes, heart disease and obesity are not a result of a single genetic cause, but they are caused due to the result of multiple genes, in combination with the environmental factors as well as the lifestyle of the person. Multifactorial Disorder is caused by the interaction of genetic and non-genetic factors along with the environmental factors.

Multifactorial Disorders are frequently seen clustering in families, but they do no have a well-established pattern of inheritance. Thus, it becomes difficult to determine whether a person is at risk to inherit or pass on this disorder to the next generation. Multifactorial Disorders are very complex, hence difficult to treat as well as study as the particular factor responsible for most of these disorders are not yet identified.

There are many common diseases seen running in the family, but the simple inheritance pattern of a single gene disorder is seen lacking there. These Multifactorial Disorders includes diseases like epilepsy, manic depression, asthma, schizophrenia and hypertension. Some of the developmental abnormalities also come under this category like the cleft palate, neural tube defects like spina bifida and congenital heart defects.

The Multifactorial Disorders have a very low heritability in comparison with the single gene disorder. For instance: only 5-7% of your close relatives or family members of diabetics suffer from the same disease, and lower would be the case for single gene disorder such as cystic fibrosis. This clearly states that a single genetic factor is never responsible to cause diseased conditions in your body. There are a number of genes that combine along with the environmental factors like exposure to hazardous chemicals or poor diets, which cause disorders in a person.

The occurrence of the Multifactorial Disorders is thought to be dependent on the balance of risks. There exists a balance between the variants of genes with positive as well as negative effects, and between environmental factors again with positive as well as negative effects. Too many negative factors, both environmental and genetic may tilt the balance towards various disorders.

In a Multifactorial Disorder, sometimes the risk may depend on the sex of the affected person. For instance, pyloric stenosis is a Multifactorial Disorder occurring five times more often in males as compared to females. If a female suffers from pyloric stenosis, her as well as her parent’s risk of having other child affected with this condition will be higher than if a male child would be suffering with it. The occurrence of this condition in females has a higher genetic liability apparently, a number of abnormal genes are isolating in the family.

Thus, we can shortly state that there is a similar risk for the first-degree relatives such as parents, siblings or offspring’s to develop Multifactorial Disorder. The severity of the disorder and the sex of the person can play a role in modifying the risk. Some of the common chronic diseases are Multifactorial Disorders of the genes. The conditions with Multifactorial Disorder include cancer, birth defects, coronary artery diseases and mental disorders.

Posted in microbiology. Tagged with .

By admin
May 18, 2009

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Escherichia coli

Escherichia coli is abbreviated, as E. coli is a diverse and a large group of bacteria. It is generally found in the lower intestine of the warm-blooded animals. The E. coli strains are harmless normally, but there are some strains like the serotype O157 are responsible in causing food poisoning in human beings. The harmless strains are beneficial to their hosts as they produce vitamin K2 and also prevents the development of pathogenic bacteria inside the intestine of the organisms.

The E. coli bacteria is one of the leading causes of bloody diarrhea and severe cramps in the body. Symptoms of E. coli infections are worst in children and elderly people, and particularly in those people who are already suffering form some other illness. The E. coli infections are prevalent normally during the months of summer and the northern states.

Causes of E. coli infections- One can easily catch these E. coli infections. The E. coli infections generally come from drinking contaminated or impure water, unpasteurized or raw milk, working with cattle’s and consuming undercooked ground beef. The dairy cattle’s and healthy beef carry this E. coli bacterium in their intestines. The meat can get contaminated with the E. coli bacterium at the time of slaughtering process. The E. coli bacterium gets mixed in the entire meat when the beef is ground up. Thus, we can say that one of the common ways of getting this infection is by consuming contaminated food.

Symptoms of E. coli infection are visible after about seven days when you get infected with the germ. Its symptoms includes watery diarrhea and severe abdominal cramps. The body loses fluids and electrolytes in a large amount due to diarrhea. This diarrhea later on changes to red, bright bloody stools. You may also experience mild fever or no fever at all and vomiting. There are some complications that arise due to this infection. Hemolytic uremic syndrome is the most common complication. People with this problem suffer from renal failure- kidney damage, thrombocytopenia- low platelet count and hemolytic anemia- low red blood cell count.

Diagnosis of E. coli infections is done by finding the E. coli in a stool sample of the concerned person. It is recommended to see a doctor soon, if you have bloody diarrhea. There is no special treatment available as such, for the treatment of the E. coli infections. You just need to drink adequate water and observe the complications. Medicine to stop the diarrhea should not be taken, as it will keep the intestines away form getting rid of the E. coli bacterium. In case of serious dehydration, fluids are put in the veins through IVs. Generally, the E. coli infections get better in a period of five to ten days.

The E. coli infections are caused by consuming the foods containing bacteria. Hence, to prevent the arousal of these infections, it is suggested to handle the food safely. Wash the fruits and vegetables before eating or cooking them, cook the meat well and avoid raw juices and milk,

Posted in microbiology.

By admin
November 12, 2008

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Dermatophyte

A Dermatophyte is defined as a parasitic fungus that is responsible for causing the infections in your skin. It is not a specific fungus, but only a short hand label for a class of three genera of fungi that often cause diseases of the skin in animals and human beings. These asexual genera are Microsporum, Epidermophyton and Trichophyton. There are approximately forty species in these three classes of genera.

Dermatophytes results in the hair infections, skin infections and nails infections as they are able to absorb the nutrients form the keratinized material. The keratin tissue is inhabited by the organisms and this result in inflammation by the host response to the metabolic by-products. Dermatophyte are often restricted to the cornified, non-living layer of the epidermis as they are unable to go through the viable tissues of the host. This invasion of the Dermatophytes educes a host response that ranges form mild to severe. Dermatophytes do not attack the living tissues usually, but they settle on the outer layer of the skin.

Classification of Dermatophyte- Dermatophyte is categorized into three classes based on their natural habitat: Anthrophilic- humans, Zoophilic-animals and Geophilic- soil. The Anthrophilic Dermatophytes limited to the human hosts only and they result in a mild and chronic infection in human beings. The Zoophilic organisms have their hosts, basically in animals. They are responsible in producing remarkable inflammatory reactions in the human beings having contact with the infected dogs, cats, birds, cattle’s, horses or any other animals. The Geophilic species are generally recovered from soil, but they cause infections in animals and human beings very often. They result in remarkable inflammatory reactions in humans and animals that limit spreading of the infection. It may result in impulsive cure, but scars of the reactions will be left behind.

Dermatophytes Transmission- The transmission of the Dermatophyte takes place either by the direct contact with the infected host that may be an animal or a human being, or by direct or indirect contact with infected caps, skin, hairs in clothing, hair brushes, comb, theatre seats, towels, rugs, furniture, locker room floorings and bed linens. It is workable in a particular environment for a period of about fifteen months, depending on the organism’s species. Susceptibility to infections is higher in cases of an already existing skin injury like burns, scars, humidity and excessive temperature.

The infections caused by the Dermatophytes can be diagnosed readily depending on the physical examination, history and KOH i.e. Potassium Hydroxide Microscopy. The diagnosis usually needs historologic examination, Wood’s Lamp examination and fungal culture. Dermatophytic infections are mostly treated by using the Topical Therapy. The courses of treatment are short; whereas the rates of cure are high with topical fungicidal allylamines rather than the fungistatic azoles.

Dermatophytes, a group of fungi are capable to cause infections and survive only on the dead keratin, which is found on the topmost layer of the hair, skin and nails. They are unable to live on the moist skin that is found inside the vagina or the mouth. Thus, they are liable in causing a number of hair, skin and nail infections in living organisms.

Posted in fungii. Tagged with .

By admin
November 11, 2008

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