What is a gene mutation and how do mutations occur?

A gene mutation is a permanent change in the DNA sequence that makes up a gene. Mutations range in size from a single DNA building block (DNA base) to a large segment of a chromosome.
Gene mutations occur in two ways: they can be inherited from a parent or acquired during a person’s lifetime. Mutations that are passed from parent to child are called hereditary mutations or germline mutations (because they are present in the egg and sperm cells, which are also called germ cells). This type of mutation is present throughout a person’s life in virtually every cell in the body.
Mutations that occur only in an egg or sperm cell, or those that occur just after fertilization, are called new (de novo) mutations. De novo mutations may explain genetic disorders in which an affected child has a mutation in every cell, but has no family history of the disorder.
Acquired (or somatic) mutations occur in the DNA of individual cells at some time during a person’s life. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation.
Mutations may also occur in a single cell within an early embryo. As all the cells divide during growth and development, the individual will have some cells with the mutation and some cells without the genetic change. This situation is called mosaicism.
Some genetic changes are very rare; others are common in the population. Genetic changes that occur in more than 1 percent of the population are called polymorphisms. They are common enough to be considered a normal variation in the DNA. Polymorphisms are responsible for many of the normal differences between people such as eye color, hair color, and blood type. Although many polymorphisms have no negative effects on a person’s health, some of these variations may influence the risk of developing certain disorders.

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Gene Cloning

Gene manipulation or gene cloning involves separating a specific gene or DNA segment from a larger chromosome, attaching or to a small molecule of carrier DNA or simply vector and then replicating this modified DNA thousands or millions of times through both an increase in cell number and the creation of multiple copies of cloned DNA in each cell. The result is selective amplification of a particular gene or DNA segment. A clone is an identical copy. These methods and related tasks are collectively referred to as recombinant DNA technology or more informally genetic engineering.
Cloning of DNA genes from any organism entails five general steps:
• Isolation of gene of interests.
• Insertion of foreign DNA into a vector.
• Introduction of the recombinant vector into host cells.
• Selection of transformed host cells.
• Cloning or mass culture of transformed host cells.

1. Isolation of gene of interests: The gene of interest can be isolated from variety of sources. The gene is either prepared from the genome by restriction enzymes or may be prepared from mRNA using reverse transcriptase.
2. Insertion of foreign DNA into a vector: The gene is fragmented by using the specific restriction enzyme to develop specific cohesive ends. The cloning vector is also treated with the same enzyme so that cohesive ends generated may have complementary residues similar to foreign DNA.
The fragments are brought together to join by DNA ligase enzyme under optimal condition. This steps provides the recombinant DNA i.e. DNA from sources.
3. Transfer of recombinant DNA into the host: Recombinant plasmid or DNA are introduced into bacterial cells by a process called transformation. The cells and plasmid DNA are incubated together at 0oC in a CaCl2 solution, then subjected to a shock by rapidly shifting the temperature to 37oC to 43oC. By doing this some of cells take up the plasmid. Electroporation can be used alternative to this method.
4. Selection of transformed cells: The transformed cells containing recombinant plasmids are identified. This is usually done by adding ‘marker gene’ in the cloning vector. These marker genes are often for antibiotic resistance.
5. Propagation or Cloning: When the required cells are selected they are cultured in nutrient medium so as to propagate the DNA into high numbers. As the bacteria divides, the recombinant DNA molecules also divide producing high number of clone genes. The cloned genes and bacteria are then used for industrial processes.

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What is Recombinant DNA Technology? Describe its medical applications

Recombinant DNA Technology is the part of genetic engineering in which cells are genetically engineered to obtain a valuable product like enzyme, metabolites, insulin, hepatitis vaccine which plays an important role in medical microbiology in addition to other prospects. The maximum benefits of biotechnology have been utilized by health care. This technology derives proteins and polypeptides to form the new class of potential drugs. Since 1982 human insulin has been produced by microorganisms in fermenters, used to treat diabetes.

Applications of Recombinant DNA technology
• Recombinant vaccine like Hepatitis-B vaccine: Microorganisms are genetically modified with Hepatitis gene and cultured so as to produce huge amount of hepatitis vaccine to treat hepatitis-B.
• Golden rice: Golden rice is medicinal plant product in which plant is recombinant with vitamin A producing gene and grown on field to obtain Golden rice which is widely used in treating blindness and malnutrition person.
• Recombinant metabolites like insulin: insulin can be produced on large scale by recombinant technology on microorganisms and used to treat the diabetic patient. Recombinant insulin is recognized by humulin.
• Recombinant enzymes: Recombinant DNA technology is done on microorganisms to produce large scale of enzyme like urease, streptodecase, alpha asparaginase, trypsin etc. for different purposes.
• Changing blood group: Enzymes provided by recombinant DNA technology is widely used to change blood group. Polysaccharides on RBC determine each type of blood group like A and B which on enzymatic hydrolysis, polysaccharides is removed and type A and B converted to O and are used widely in blood transfusion.
• Gene Therapy to cure genetic disease: Gene therapy is done directly by gene gun into patient body to cure a genetic disease which is also a recombinant technology.
• Criminal Investigation: DNA finger printing or polymerase chain reaction is a recombinant DNA technology in which single gene is amplified on large scale an investigate criminal on the basis of genome sequence.
• Diagnostic mechanism: Monoclonal anti body like immunoglobin can be produced on large scale by recombination of microorganisms with antibody gene and these monoclonal antibodies is used to depict pregnancy, cancer, allergy etc.
• Prevents from environmental disease: Recombinant DNA technology nowdays become basic tool obtaining recombinant organism for achieving metabolites which are responsible for eliminating environmental pollution. As it clears environment, it protests from disease, caused by pollutions. For eg. Pseudomonas putida used to treat oil spillage on sea and prevents from disease caused by oil on consumption through water.

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What is a gene mutation and how do mutations occur?

A gene mutation is a permanent change in the DNA sequence that makes up a gene. Mutations range in size from a single DNA building block (DNA base) to a large segment of a chromosome.
Gene mutations occur in two ways: they can be inherited from a parent or acquired during a person’s lifetime. Mutations that are passed from parent to child are called hereditary mutations or germline mutations (because they are present in the egg and sperm cells, which are also called germ cells). This type of mutation is present throughout a person’s life in virtually every cell in the body.
Mutations that occur only in an egg or sperm cell, or those that occur just after fertilization, are called new (de novo) mutations. De novo mutations may explain genetic disorders in which an affected child has a mutation in every cell, but has no family history of the disorder.
Acquired (or somatic) mutations occur in the DNA of individual cells at some time during a person’s life. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation.
Mutations may also occur in a single cell within an early embryo. As all the cells divide during growth and development, the individual will have some cells with the mutation and some cells without the genetic change. This situation is called mosaicism.
Some genetic changes are very rare; others are common in the population. Genetic changes that occur in more than 1 percent of the population are called polymorphisms. They are common enough to be considered a normal variation in the DNA. Polymorphisms are responsible for many of the normal differences between people such as eye color, hair color, and blood type. Although many polymorphisms have no negative effects on a person’s health, some of these variations may influence the risk of developing certain disorders.

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Carbohydrate

Carbohydratesl Also called saccharides
- The name carbohydrate is derived from (C-H2O)n, or 'hydrate of carbon.'
- They are mostly produced by photosynthesis
- Crucial role in in living organism:
- energy storage
-protective coating
-derivates of other biological molecules
Monosaccharides:l the smallest units of carbohydrate structure.
- empirical formula (CH2O)n, where n >= 3 (n is usually five or six but can be up to nine).
Oligosaccharidesl polymers of 2 - 20 monosaccharide residues.
- most common oligosaccharides are the disaccharides
Polysaccharides
- polymers that contain usually > 20 monosaccharide residues.
-do not have the empirical formula (CH2O)
Glycoconjugates
- carbohydrate derivatives in which one or more carbohydrate chains are linked covalently to a peptide chain,
protein, or lipid.

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Transcription Process

RNA polymerase is responsible for the transcription of all RNAs. RNA polymerase fron prokaryote is a complex holoenzyme with 5 polypeptide sub units: 2 alpha, 1 beta , 1 beta’ and 1 sigma factor. The enzyme without sigma factor is referred to as core enzyme.
Transcription involves 3 different stages:
1. Initiation
2. Elongation
3. Termination

Initiation
Initiation of transcription involves the binding of RNA polymerase (holoenyme to a region of DNA. The specific region is known as promoter region. In promoter region, polymerase complex undergoes structural changes so that the DNA around the point will start unwinding and the base pairs are disrupted, producing a bubble off ssDNA. Two characteristic nucleotide sequences or base sequence in coding strand are recognized by RNA polymerase (Holoenzyme) which are:
i. Prinbow box: This consists of 6 nucleotide bases (TATAAT), located on the left side about 10 bases upstream from starting point.
ii. -35 sequences: A second sequence located about 35 bases upstream the transcription start point. Base sequences are TTGACA.

Elongation
After the promoter region has been recognized by the holoenzyjme, RNA polymerase begins to synthesize the transcript of the DNA sequence and sigma subunit is released. RNA is synthesized from 5’ to 3’ end antiparallel to DNA template. RNA polymerase utilizes ribonucleoside Triphosphate (ATP, GTP, CTP and UTP) and release pyrophosphate each time a nucleotide is added to the growing chain. The nucleotide bases in mRNA synthesized is complementary to template DNA and identical to that of coding strand.
RNA polymerase does not need prier and doesn’t possess endo or exonuclease activity. As the transcription bubble moves left to right, the DNA is unwinded ahead and rewinded behind as RNA transcribed.

Termination
Once the polymerase has transcribed the length of the gene’ it must stop and release the RNA product. This is called termination. In bacterias terminator comes in two types:
i. Rho Independent
ii. Rho dependent

Rho Independent Terminator
This is also called intrinsic terminator which consists of two sequence elements.
i. A short inverted repeats of about 20 nucleotides followed by a stretch of about eight AT base pairs plays abd important role. When a polymerase transcribe and inverted repeat sequence, the resulting RNA can form a stem loop structure (often called hairpin) by base pairing with itself. Near the base of the stem of hairpin, a sequence occur ie. Rich in G and C which is responsible for stabilization of hairpin structure. This stable hairpin slows down the progress of RNA polymerase and causes it to pause.
ii. The hairpin only work as an efficient termination when it is followed by a stretch of AU base pairs. As AU base pairs are the weaker base pairs , they are more disrupted by the effect of the stem loop on the transcribing polymerase and so the RNA will more easily be disrupted.

Rho Dependent TerminatorA specific protein rho factor binds to a C- rich region near 3’ end of growing RNA and migrates in 5’ to 3’ direction until it reaches the transcription complex that is paused at a termination site with the release of transcript RNA. The rho protein has ATP dependent RNA-DNA helicase activity.

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What is transcription?

Transcription is a process in which ribonucleic acid (RNA) is synthesizes from deoxyribonucleic acid (DNA). Thus the genetic information stored in DNA is expressed through RNA. For this purpose one of the two strands of DVA serves as a template (non coding strand or sense strand) and produces working copies of RNA molecule. The other DNA strand not participating in transcription is coding or anti-sense strand. RNAs are synthesized only for some selected region of DNA rather than entire DNA. A single enzyme RNA polymerase synthesizes all the RNAs in prokaryotes.

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Swine Flu Now Reported in All 50 States in US

June 1 (HealthDay News) -- Swine flu cases have now been reported in all 50 states, with the total number of people infected probably surpassing 200,000, U.S. health officials said Monday.

"It's accurate to say that there are probably several hundred thousand people that have been impacted by this flu," said Tom Skinner, a spokesman for the U.S. Centers for Disease Control and Prevention. "But that's in line with what we would see with seasonal influenza if we had the number of cases we are reporting right now."

And while the outbreak continues to wane, new cases will continue to emerge, Skinner said.

On Monday, the CDC was reporting a total of 10,053 cases in all 50 states and the District of Columbia, including 17 deaths. The agency has said in the past that confirmed cases of H1N1 swine flu represent about one in 20 of actual cases, bringing the total number of cases to about 200,000.

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Genes of new flu virus show it's not so new

WASHINGTON (Reuters) - The most complete analysis yet of the new H1N1 swine flu virus shows it must have been circulating undetected for years, most likely in pigs, researchers said on Friday. They said pigs are clearly a potential source of human pandemics. "The results of the study show the global need for more systematic surveillance of influenza viruses in pigs," Dr. Nancy Cox, chief of the influenza division at the U.S. Centers for Disease Control and Prevention, told reporters in a telephone briefing.

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U.S. swine flu deaths hit double digits

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Tokyo precaution against swine flu

Japanese students wear facial masks as a precaution against swine flu while touring the Senso-ji temple area, one of tourists destinations in downtown Tokyo on Thursday, a day after a 16-year-old girl in Tokyo was confirmed to have swine flu — the first case in the Japanese capital.

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Symptoms of Swine flu

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Visualizing the HIV pandemic

Hans Rosling unveils new data visuals that untangle the complex risk factors of one of the world’s deadliest (and most misunderstood) diseases: HIV. He argues that preventing transmissions - not drug treatment - is the key to ending the epidemic.

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Swine flu hits 8,800 people

Swine flu has affected 8,829 people in 40 countries across the globe and caused the death of 74, the deputy head of the WHO said. Fuji Fukuda said that 95% of the cases remained in North America, Japan had leapt up the table with 125, against only seven.

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Global Outbreak of Swine flu

December 2005 to January 2009
CDC receives reports of 12 cases of swine flu infection.
March
March 28
Believed to be the date of the earliest onset of the swine flu cases in the U.S., according to Dr. Nancy Cox of the CDC.
Late March
4-year-old boy contracts swine flu in Mexico.
April
April 6
Local health officials declare a health alert due to a respiratory disease outbreak in the Mexican town of La Gloria in Veracruz state.
April 13
Woman dies of swine flu in Oaxaca state, Mexico.
April 17
10-year-old boy from San Diego County and 9-year-old girl in Imperial County of California diagnosed. Both children first became sick in late March, but recovered.
April 21
Health officials alert U.S. doctors to the new strain of swine flu — a combination of swine, avian and human influenza that had not been seen before.
April 22
CDC confirms three more cases of swine flu in California and two in Texas.

The Oaxaca Health Department in Mexico indicates 16 employees at the Hospital Civil Aurelia Valdivieso have contracted respiratory disease.
April 24
In Mexico, at least 20 have died — though WHO counts 57 — and more than 900 sickened. Seven of 14 samples from Mexico test positive for the new strain. Government closes schools, museums, libraries and theaters to try to contain outbreak.

Eight people in the U.S. are confirmed to have swine flu.

Makers of Relenza and Tamiflu confirm that swine flu is susceptible to their antiviral drugs.
April 25
New York City officials report that more than 100 high-school students at St. Francis Preparatory School in Queens are ill with flu-like symptoms.

Confirmed U.S. cases rises to 11.

WHO calls emergency meeting of experts to consider declaring an international public health emergency. It is the first time such a panel has been called since the procedure was created two years ago.
April 26
Confirmed U.S. cases rise to 20, and a public health emergency is declared. Eight of the confirmed cases are from a New York City private school.

New Zealand, France, Israel, Brazil and Spain report suspected cases. Six cases are confirmed in Canada.

Up to 86 deaths in Mexico are suspected to be linked to swine flu. Possible cases reported in 19 of country's 32 states.
April 27
WHO raises the pandemic alert one level to phase 4, which is two steps short of declaring a full-blown pandemic.

The U.S. government confirms there are now 42 cases, with the 20 new ones from the New York City preparatory school.

In Europe, Spain confirms its first swine flu case, Scotland’s health secretary confirms two cases and 17 other cases are suspected across the continent.

The new virus is suspected in up to 149 deaths in Mexico.
April 28
Confirmed cases in the U.S. rise to 68. Seven have been hospitalized.

President Obama asks for $1.5 billion in emergency funds to fight the disease.

First cases confirmed in Middle East and Asia-Pacific region.

Number of deaths blamed on virus surpasses 150 in Mexico, though only 26 have been confirmed. Restaurants are ordered to limit service to takeout, and pool halls and gyms are closed.

Cuba becomes the first country to impose a travel ban, suspending flights to and from Mexico. Argentina follows with its own five-day ban.

April 29
The number of confirmed cases in the U.S. rises to 93. A child in Texas who was visiting from Mexico dies from swine flu.

Mexico announces it will suspend nonessential services at government offices and private businesses from May 1-5.

Pentagon confirms one Marine based in Southern California tested positive. He was placed under quarantine along with about 30 other Marines.

WHO raises pandemic level to 5.

Egypt begins slaughtering about 300,000 pigs as a precaution.

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Swine Flu

Swine influenza is a respiratory disease of pigs first isolated in swine in 1930, according to the Centers for Disease Control and Prevention. The illness is caused by four different type A influenza strains that can cause outbreaks in pigs, though subtypes H1N1 and H3N2 seem to be more common. The death rate among pigs is low, with most infections occurring in the late fall and winter. Symptoms of infected pigs include fever, depression, coughing (barking), sneezing, difficulty breathing, red or inflamed eyes, lack of appetite and discharge from the nose or eyes.

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T.U. Curriculum for Microbiology Ist Year

1. Chronological development of microbiology and discovery: Introductin, Microorganism as a cell, General history of microbiology and microorganisms, Microbial diversity, Discovery of microorganisms, Spontaneous generation, Germ theory of disease
2. Correlate Microbiology with different areas: Discipline of Microbiology, Mental and public health microbiology, Agricultural microbiology, Food microbiology, Microbial biotechnology, Industrial and environmental microbiology.
3. Nomenclature of Microorganisms: Classification and nomenclature
4. Physiology of Bacteria: Introduction, Morphological characteristics and the fine structure of bacteria, Nutrition, Reproduction and Cultivation.
5. Fungus: Fungi, Classification, Structure, Growth and Reproduction, Fungi of medical importance.
6. Introductory Parasitology: Protozoan, Structure and reproduction, Nematodes, structure and its role in agriculture.
7. Microbial Techniques:
8. Handling Microorganisms
9. Methods of Sterilization
10. Physiological Characteristics of Microorganisms
11. Biochemical Properties of Microorganisms
12. Microbial Genetics
13. Ecological Factors in the Microbial World
    

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Why is Microbiology important?

Microorganisms occur nearly everywhere in nature. Since the conditions that favour the survival and growth of many microorganisms are those under which people normally live, it is inevitable that we live among a multitude of microbes. Microorganisms affect the well being of people in a great ways. They bring many changes; some desirable and some undesirable. To know about the beneficial and non beneficial microbes and their roles in our life, microbiology must be a great deal of study. They can be summarizes as follow:

1. Disease. Since discovery of infectious microbes, most infectious diseases controlled by sanitation, preventive medicine, and chemotherapy.
2. Agriculture. microbes vital in processing materials in soil, e.g. nitrogen, sulfur, etc.
3. Food and drink. Microbial fermentations responsible for all alcoholic beverages, breads, pickles, cheeses, etc. Control of food and drink spoilage is major concern of food industry.
4. Chemical products. Microbes have incredible variety of metabolic tricks; can be used to produce acetone and other commercial solvents, pharmaceuticals, antibiotics, preservatives, etc.
5. Basic research. Microbes grow fast, produce enormous # of offspring. Easy to find events that occur only 1 in a billion times if have 100 billion bacteria in test tube. Crucial to modern biology.
6. Biotechnology. E.g. genetic engineering, ability to move genes freely from one organism to another, select genes of interest and amplify their expression. Bacteria are natural hosts for such activities.

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What is microbiology?

Microbiology is the study of living organisms of microscopic size, which include bacteria, fungi, algae, protozoa, and the infectious agents at the borderline of life that are called viruses. It is concerned with their form, structure, reproduction, physiology, metabolism, and classification. It includes the study of their distribution in nature, their relationship to each other and to other living organisms, their effects on human beings and on other animals and plants, their abilities to make physical and chemical changes in our environment, and their reactions to physical and chemical agents. Microbiology is an specialized field of a biology which deals with the study of microorganism and their effects on human and environment regarding public healtha and hygiene, quality control food and beverages, biotechnology related different industrial processes, etc.

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