("auxano" -- "I grow").

uxins derive their name from the Greek word αυξανω ("auxano" -- "I grow"). They were the first of the major plant hormones to be discovered and are a major coordinating signal in plant development. Their pattern of active transport through the plant is complex. They typically act in concert with (or opposition to) other plant hormones. For example, the ratio of auxin to cytokinin in certain plant tissues determines initiation of root versus shoot buds. Thus a plant can (as a whole) react on external conditions and adjust to them, without requiring a nervous system. On a molecular level, auxins have an aromatic ring and a carboxylic acid group (Taiz and Zeiger, 1998).
The most important member of the auxin family is indole-3-acetic acid (IAA). It generates the majority of auxin effects in intact plants, and is the most potent native auxin. However, molecules of IAA are chemically labile in aqueous solution, so IAA is not used commercially as a plant growth regulator.
Naturally-occurring auxins include 4-chloro-indoleacetic acid, phenylacetic acid (PAA) and indole-3-butyric acid (IBA).
Synthetic auxin analogs include 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and others

uxins are often used to promote initiation of adventitious roots and are the active ingredient of the commercial preparations used in horticulture to root stem cuttings. They can also be used to promote uniform flowering, to promote fruit set, and to prevent premature fruit drop.
Used in high doses, auxin stimulates the production of ethylene. Excess ethylene can inhibit elongation growth, cause leaves to fall (leaf abscission), and even kill the plant. Some synthetic auxins such as 2,4-D and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) have been used as herbicides. Broad-leaf plants (dicots) such as dandelions are much more susceptible to auxins than narrow-leaf plants (monocots) like grass and cereal crops. These synthetic auxins were the active agents in Agent Orange, a defoliant used extensively by American forces in the Vietnam War.

Ashwagandha

Common name: Winter Cherry • Hindi: Ashwagandha अश्वगंधा, Rasbhari • Kannada: Kanchuki • Marathi: Ghoda, Tilli • Gujarati: Ghodaasun • Telugu: Vajigandha • Malayalam: Amukkuram • Tamil: Amukkuram Botanical name: Withania somnifera Family: Solanaceae (Potato family)
Ashwagandha, is native to drier parts of India. It is a perennial herb that reaches about 6 feet in nature. In the greenhouse they flower in the late fall and winter. Orange fruits in persistent papery calyxes follow the small greenish flowers. Ashwagandha is propagated by division, cuttings or seed. Seed is the best way to propagate them. Seed sown on moist sand will germinate in 14-21 days at 20° C. A postal stamp was issued by the Indian Postal Department to commemorate this flowers. Medicinal uses: Ashwagandha has been a prized top notch adaptogenic tonic in India for 3000 - 4000 years. The plants contain the alkaloids withanine and somniferine, which are used to treat nervous disorders, intestinal infections and leprosy. All plant parts are used including the roots, bark, leaves, fruit and seed.

Bio-reactor”

Description
“Bio-reactor” is a generic term for a system that degrades contaminants in groundwater and soil with microorganisms. The reactors can be open systems, such as a constructed wetland (described as a separate technology), or an enclosed chamber. This description only describes the latter. Unlike natural attenuation and in-situ bioremediation, bioreactors can avoid and control the frequent problems of ineffective indigenous microorganisms and/or low indigenous microbial populations. There are several types of bio-reactors.The most common bioreactor is used in wastewater treatment. Contaminated groundwater is circulated in an aeration basin where microbes degrade organic matter, forming a sludge that is disposed of or recycled. A second type uses a rotating biological matrix. Microorganism populations grow on the matrix, which is rotated in the reactor. Another method uses a packed bed. A tank is filled with a support medium,, which provides a large surface area for microbial growth. Another system uses soil slurry bioreactor technology to degrade soil containing trinitrotoluene (TNT) and Royal Demolition Explosive (RDX).
Bioreactors can also be installed in-situ (i.e., in place). Vertically placed bio-reactors are called bio-plugs. Horizontally placed bio-reactors are called bio-conduits. These techniques enhance degradation as contaminated groundwater passes through the reactor. This technology has been successfully implemented in the remediation of organic compounds at several leaking underground storage tank and industrial sites.
Limitations and Concerns
Contaminated groundwater is often too dilute to support an adequate microbial population. At the other extreme, very high concentrations may be toxic to microorganisms. Also, heavy metals are not treated by this method, and they can be toxic to microorganisms.
Low ambient temperatures can decrease biodegradation rates.
If contaminants tend to volatilize, air pollution controls may be necessary.
With explosive materials or chlorinated solvents, some intermediary degradation products are more toxic than the original contaminants.
Bioreactors are prone to upset. Nuisance microorganisms can predominate and reduce treatment effectiveness.
Residuals may require treatment or disposal.
Applicability
Bio-reactors are used primarily to treat volatile organic compounds (VOCs) and fuel hydrocarbons. The process is less effective for pesticides. In one application, the concept was used to treat soil containing TNT and RDX. In the laboratory, it operated under aerobic and anaerobic conditions, and there was a large decrease in contaminant concentration. Intermediate byproducts were also degraded.
In-situ bioreactors can also be used to provide a cometabolite for degradation of hazardous by-products produced during the degradation process of some of the chlorinated solvents. This type of bioreactor contains adapted microbes that mineralize the organic compounds of interest. The microbes are trapped onto a biological support medium. An in-situ immobilized bioreactor system can be used in conjunction with a vapor extraction system.
Technology Development Status
Basic bio-reactors are a well-developed technology that has been used in the treatment of municipal and industrial wastewater. Bioreactors are commercially available for treating fuels. Adaptations have been recently evaluated only for treating groundwater and soil containing large concentrations of chemical contaminants. Several successful pilot projects have been completed for chlorinated compounds. Laboratory experiments have been done for explosive compounds. Sequencing anaerobic/aerobic bioreactors is an innovative approach for treating halogenated VOCs, semi-volatile organic compounds (SVOCs), pesticides, polychlorinated biphenyls (PCB), and ordnance compounds.

Process of drug discovery

Process of drug discovery

Discovery
The first step of drug discovery involves the identification of new active compounds, often called "hits", which are typically found by screening many compounds for the desired biological properties. These hits can come from natural sources, such as plants, animals, or fungi. More often, the hits can come from synthetic sources, such as historical compound collections and combinatorial chemistry.

Optimization
The second step of drug discovery involves the synthetic modification of the hits in order to improve the biological properties of the compound pharmacophore. The quantitative structure-activity relationship (QSAR) of the pharmacophore play an important part in finding lead compounds, which exhibit the most potency, most selectivity, best pharmacokinetics and least toxicity. QSAR involves mainly physical chemistry and molecular docking tools (CoMFA and CoMSIA), that leads to tabulated data and first and second order equations. There are many theories, the most relevant being Hansch's analysis that involves Hammett electronic parameters, steric parameters and logP(lipophilicity) parameters.

Development
The final step involves the rendering the lead compounds suitable for use in clinical trials. This involves the optimization of the synthetic route for bulk production, and the preparation of a suitable drug formulation.

Training in medicinal chemistry
Many workers in the field do not have formal training in medicinal chemistry. Graduate (postgraduate) level programs do exist in medicinal chemistry, but frequently the broader education in a chemistry graduate program can provide many of the skills needed.

growth factors

Growth factor is sometimes used interchangeably among scientists with the term cytokine. Historically, cytokines were associated with hematopoietic (blood forming) cells and immune system cells (e.g., lymphocytes and tissue cells from spleen, thymus, and lymph nodes). For the circulatory system and bone marrow in which cells can occur in a liquid suspension and not bound up in solid tissue, it makes sense for them to communicate by soluble, circulating protein molecules. However, as different lines of research converged, it became clear that some of the same signaling proteins the hematopoietic and immune systems used were also being used by all sorts of other cells and tissues, during development and in the mature organism.
While growth factor implies a positive effect on cell division, cytokine is a neutral term with respect to whether a molecule affects proliferation. In this sense, some cytokines can be growth factors, such as G-CSF and GM-CSF. However, some cytokines have an inhibitory effect on cell growth or proliferation. Yet others, such as Fas ligand are used as "death" signals; they cause target cells to undergo programmed cell death or apoptosis.

Example of growth factors
Individual growth factor proteins tend to occur as members of larger families of structurally and evolutionarily related proteins. There are dozens and dozens of growth factor families such as TGF-beta (transforming growth factor-beta), BMP (bone morphogenic protein), neurotrophins (NGF, BDNF, and NT3), fibroblast growth factor (FGF), and so on.
Several well known growth factors are:
1Transforming growth factor beta (TGF-β)
2Granulocyte-colony stimulating factor (G-CSF)
3Granulocyte-macrophage colony stimulating factor (GM-CSF)
4Nerve growth factor (NGF)
5Neurotrophins
6Platelet-derived growth factor (PDGF)
7Erythropoietin (EPO)
8Thrombopoietin (TPO)
9Myostatin (GDF-8)
10Growth differentiation factor-9 (GDF9)
11Acidic fibroblast growth factor (aFGF or FGF-1)
12Basic fibroblast growth factor (bFGF or FGF-2)
13Epidermal growth factor (EGF)
14Hepatocyte growth factor (HGF)

.

vaccine

A vaccine is a biological preparation which is used to establish or improve immunity to a particular disease.

Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine).

The term "vaccine" derives from Edward Jenner's 1796 use of cowpox (Latin variolæ vaccinæ, adapted from the Latin vaccīn-us, from vacca cow), which, when administered to humans, provided them protection against smallpox.

History

The earliest vaccines were based on the concept of variolation originating in China, in which a person is deliberately infected with a weak form of smallpox as a form of inoculation. Jenner realized that milkmaids who had contact with cowpox did not get smallpox. The process of distributing and administrating vaccines is thus referred to as "vaccination". Jenner's work was continued by Louis Pasteur and others in the 19th century. Since vaccination against smallpox was much safer than smallpox inoculation, the latter fell into disuse and was eventually banned in England in 1849.

The 19th and 20th centuries saw the introduction of several successful vaccines against a number of infectious diseases. These included bacterial and viral diseases, but not (to date) any parasitic diseases.

Types

Avian Flu vaccine development by reverse genetics techniques.

Vaccines may be dead or inactivated organisms or purified products derived from them.

There are four types of traditional vaccines:^[1]

• Vaccines containing killed microorganisms - these are previously virulent micro-organisms which have been killed with chemicals or heat. Examples are vaccines against flu, cholera, bubonic plague, and hepatitis A.
• Vaccines containing live, attenuated virus microorganisms - these are live micro-organisms that have been cultivated under conditions that disable their virulent properties or which use closely-related but less dangerous organisms to produce a broad immune response. They typically provoke more durable immunological responses and are the preferred type for healthy adults. Examples include yellow fever, measles, rubella, and mumps. The live tuberculosis vaccine is not the contagious strain, but a related strain called "BCG"; it is used in the United States very infrequently.
• Toxoids - these are inactivated toxic compounds in cases where these (rather than the micro-organism itself) cause illness. Examples of toxoid-based vaccines include tetanus and diphtheria. Not all toxoids are for micro-organisms; for example, Crotalis atrox toxoid is used to vaccinate dogs against rattlesnake bites.
• Subunit - rather than introducing an inactivated or attenuated micro-organism to an immune system (which would constitute a "whole-agent" vaccine), a fragment of it can create an immune response. Characteristic examples include the subunit vaccine against HBV that is composed of only the surface proteins of the virus (produced in yeast) and the virus-like particle (VLP) vaccine against human papillomavirus (HPV) that is composed of the viral major capsid protein.

A number of innovative vaccines are also in development and in use:

• Conjugate - certain bacteria have polysaccharide outer coats that are poorly immunogenic. By linking these outer coats to proteins (e.g. toxins), the immune system can be led to recognize the polysaccharide as if it were a protein antigen. This approach is used in the Haemophilus influenzae type B vaccine.
• Recombinant Vector - by combining the physiology of one micro-organism and the DNA of the other, immunity can be created against diseases that have complex infection processes
• DNA vaccination - in recent years a new type of vaccine, created from an infectious agent's DNA called DNA vaccination, has been developed. It works by insertion (and expression, triggering immune system recognition) into human or animal cells, of viral or bacterial DNA. Some cells of the immune system that recognize the proteins expressed will mount an attack against these proteins and cells expressing them. Because these cells live for a very long time, if the pathogen that normally expresses these proteins is encountered at a later time, they will be attacked instantly by the immune system. One advantage of DNA vaccines is that they are very easy to produce and store. As of 2006, DNA vaccination is still experimental.

While most vaccines are created using inactivated or attenuated compounds from micro-organisms, synthetic vaccines are composed mainly or wholly of synthetic peptides, carbohydrates or antigens.

Vaccines may be monovalent (also called univalent) or multivalent (also called polyvalent). A monovalent vaccine is designed to immunize against a single antigen or single microorganism.^[2] A multivalent or polyvalent vaccine is designed to immunize against two or more strains of the same microorganism, or against two or more microorganisms.^[3]

ORYZA

Scientific classification
Kingdom:Plantae
(unranked):Angiosperms
(unranked):Monocots
(unranked):Commelinids
Order:Poales
Family:Poaceae
Subfamily:Bambusoideae
Tribe:Oryzeae
Genus:OryzaL.

Oryza is a genus of 7-20 species of grasses in the tribe Oryzeae, within the subfamily Bambusoideae. native to tropical and subtropical regions of Asia and Africa. They are tall wetland grasses, growing to 1-2 m tall; the genus includes both annual and perennial species.
Oryza is situated within the tribe Oryzeae, which is characterized morphologically by its single flowered spikelets whose glumes are almost completely suppressed. In Oryza, two sterile lemma simulate glumes. The tribe Oryzeae is within the subfamily Bambusoideae, a group of Poaceae tribes with certain features of internal leaf anatomy in common. The most distinctive leaf character of this subfamily is their arm cells and fusoid cells found in their leafs. The Bambusoideae are in the family Poaceae, as they all have fibrous root systems, cylindrical stems, sheathing leaves with parallel veined blades, and inflorescences with spikelets. [1]
While USDA plants lists only 7 species, others have identified up to 17, including sativa, barthii, glaberrima, meridionalis, nivara, rufipogon, punctata, latifolia, alta, grandiglumis, eichingeri, officinalis, rhisomatis, minuta, australiensis, granulata, meyeriana, and brachyantha. One species, Rice (O. sativa), provides twenty percent of global grain and is a food crop of major global importance. The many species mentioned above are divided into two subgroups within the genus
Selected species
Oryza barthii
Oryza glaberrima
Oryza latifolia
Oryza longistaminata
Oryza punctata
Oryza rufipogon
Oryza sativa

DNA structure

DNA structure
Main article: DNA

The chemical structure of DNA.
DNA usually exists in a double-stranded structure, with both strands coiled together to form the characteristic double-helix. Each single strand of DNA is a chain of four types of nucleotide: adenine, cytosine, guanine, and thymine. A nucleotide consists of a phosphate and a deoxyribose sugar forming the backbone of the DNA double helix plus a base that points inwards. Nucleotides are matched between strands through hydrogen bonds to form base pairs. Adenine pairs with thymine and cytosine pairs with guanine.
The physical pairing of bases in DNA means that the information contained within each strand is redundant. The nucleotides on a single strand can be used to reconstruct nucleotides on a newly synthesized partner strand.
DNA strands have a directionality, and the different ends of a single strand are called the "3' end" and the "5' end" (these refer to the carbon atom in ribose that the next phosphate in the chain attaches to). In addition to being complementary, the two strands of DNA are antiparallel: they are orientated in opposite directions. This directionality has consequences in DNA synthesis, because DNA polymerase can only synthesize DNA in one direction by adding nucleotides to the 3' end of a DNA strand

DNA polymerase
Main article: DNA polymerase

DNA polymerase adds nucleotides to the 3' end of a strand of DNA. If a mismatch is accidentally incorporated, the polymerase is inhibited from further extension. Proofreading removes the mismatched nucleotide and extension continues.
DNA polymerases are a family of enzymes critical for all forms of DNA replication.[4] A DNA polymerase synthesizes a new strand of DNA by extending the 3' end of an existing nucleotide chain, adding new nucleotides matched to the template strand one at a time. Some DNA polymerases may also have some proofreading ability, removing nucleotides from the end of a strand in order to remove any mismatched bases. DNA polymerases are generally extremely accurate, making less than one error for every 109 nucleotides added.
The energy for the process of DNA polymerization comes from the two additional phosphates attached to each of the unincorporated nucleotides. These free nucleotides, also known as nucleoside triphosphates, contain a total of three phosphates. When a nucleotide is being added to a growing DNA strand, two of the phosphates are removed and the energy produced is used to attach the remaining phosphate to the growing chain. The energetics of this process may also explain the directionality of synthesis - if DNA were synthesized in the 3' to 5' direction, the energy for the process would come from the 5' end of the growing strand rather than from free nucleotides. During proofreading, if the 5' nucleotide needed to be removed this triphosphate end would be lost, losing the energy source required to add a new nucleotide to the end.
DNA polymerase can only extend an existing DNA strand paired with a template strand, it cannot begin the synthesis of a new strand. To do this a short fragment of DNA or RNA, called a primer, must be created and paired with the template strand before DNA polymerase can synthesize new DNA.

[DNA replication within the cell
Main articles: Prokaryotic DNA replication and Eukaryotic DNA replication

Origins of replication
For a cell to divide, it must first replicate itself into newer ones DNA.

[5] This process is initiated at particular points within the DNA, known as "origins", which are targeted by proteins that separate the two strands and initiate DNA synthesis.

[3] Origins contain DNA sequences recognized by replication initiator proteins (eg. dnaA in E coli' and the Origin Recognition Complex in yeast).

[6] These initiator proteins recruit other proteins to separate the two strands and initiate replication forks.
Initiator proteins recruit other proteins to separate the DNA strands at the origin, forming a bubble. Origins tend to be "AT-rich" (rich in adenine and thymine bases) to assist this process because A-T base pairs have two hydrogen bonds (rather than the three formed in a C-G pair)—strands rich in these nucleotides are generally easier to separate.

[7] Once strands are separated, RNA primers are created on the template strands and DNA polymerase extends these to create newly synthesized DNA.
As DNA synthesis continues, the original DNA strands continue to unwind on each side of the bubble, forming replication forks. In bacteria, which have a single origin of replication on their circular chromosome, this process eventually creates a "theta structure" (resembling the Greek letter theta: θ).

In contrast, eukaryotes have longer linear chromosomes and initiate replication at multiple origins within these.

photorespiration

The details of photorespiration
The uptake of O2 by RUBISCO forms:
the 3-carbon molecule 3-phosphoglyceric acid — just as in the Calvin cycle
the 2-carbon molecule glycolate.
The glycolate enters peroxisomes where it uses O2 to form intermediates that
enter mitochondria where they are broken down to CO2. So this process uses O2 and liberates CO2 as cellular respiration does which is why it is called photorespiration.
It undoes the good anabolic work of photosynthesis, reducing the net productivity of the plant. For this reason, much effort — so far largely unsuccessful — has gone into attempts to alter crop plants so that they carry on less photorespiration.
The problem may solve itself. If atmospheric CO2 concentrations continue to rise, perhaps this will enhance the net productivity of the world's crops by reducing losses to photorespiration.

C4 Plants
Over 8000 species of angiosperms, scattered among 18 different families, have developed adaptations which minimize the losses to photorespiration. They all use a supplementary method of CO2 uptake which forms a 4-carbon molecule instead of the two 3-carbon molecules of the Calvin cycle. Hence these plants are called C4 plants. (Plants that have only the Calvin cycle are thus C3 plants.)
Some C4 plants — called CAM plants — separate their C3 and C4 cycles by time. CAM plants are discussed below.
Other C4 plants have structural changes in their leaf anatomy so that
their C4 and C3 pathways are separated in different parts of the leaf with
RUBISCO sequestered where the CO2 level is high; the O2 level low.These adaptations are described now.
The details of the C4 cycle
After entering through stomata, CO2 diffuses into a mesophyll cell.
Being close to the leaf surface, these cells are exposed to high levels of O2, but
have no RUBISCO so cannot start photorespiration (nor the dark reactions of the Calvin cycle).
Instead the CO2 is inserted into a 3-carbon compound (C3) called phosphoenolpyruvic acid (PEP) forming
the 4-carbon compound oxaloacetic acid (C4).
Oxaloacetic acid is converted into malic acid or aspartic acid (both have 4 carbons), which is
transported (by plasmodesmata) into a bundle sheath cell. Bundle sheath cells
are deep in the leaf so atmospheric oxygen cannot diffuse easily to them;
often have thylakoids with reduced photosystem II complexes (the one that produces O2).
Both of these features keep oxygen levels low.
Here the 4-carbon compound is broken down into
carbon dioxide, which enters the Calvin cycle to form sugars and starch.
pyruvic acid (C3), which is transported back to a mesophyll cell where it is converted back into PEP.These C4 plants are well adapted to (and likely to be found in) habitats with
high daytime temperatures
intense sunlight. Some examples:
crabgrass
corn (maize)
sugarcane
sorghum
C4 cells in C3 plantsThe ability to use the C4 pathway has evolved repeatedly in different families of angiosperms. Perhaps the potential is in them all.
A report in the 24 January 2002 issue of Nature (by Julian M. Hibbard and W. Paul Quick) describes the discovery that tobacco, a C3 plant, has cells capable of fixing carbon dioxide by the C4 path. These cells are clustered around the veins (containing xylem and phloem) of the stems and also in the petioles of the leaves. In this location, they are far removed from the stomata that could provide atmospheric CO2. Instead, they get their CO2 and/or the 4-carbon malic acid in the sap that has been brought up in the xylem from the roots.
If this turns out to be true of many C3 plants, it would explain why it has been so easy for C4 plants to evolve from C3 ancestors.
CAM PlantsThese are also C4 plants but instead of segregating the C4 and C3 pathways in different parts of the leaf, they separate them in time instead. (CAM stands for crassulacean acid metabolism because it was first studied in members of the plant family Crassulaceae.)
At night,
CAM plants take in CO2 through their open stomata (they tend to have reduced numbers of them).
The CO2 joins with PEP to form the 4-carbon oxaloacetic acid.
This is converted to 4-carbon malic acid that accumulates during the night in the central vacuole of the cells.In the morning,
the stomata close (thus conserving moisture as well as reducing the inward diffusion of oxygen).
The accumulated malic acid leaves the vacuole and is broken down to release CO2.
The CO2 is taken up into the Calvin (C3) cycle.These adaptations also enable their owners to thrive in conditions of
high daytime temperatures
intense sunlight
low soil moisture.Some examples of CAM plants:
cacti
Bryophyllum
the pineapple and all epiphytic bromeliads
sedums
the "ice plant" that grows in sandy parts of the scrub forest biome

MELANIN IN HUMANS

In humans, melanin is the primary determinant of human skin color and also found in hair, the pigmented tissue underlying the iris, the medulla and zona reticularis of the adrenal gland, the stria vascularis of the inner ear, and in pigment-bearing neurons within areas of the brain stem, such as the locus ceruleus and the substantia nigra.
Dermal melanin is produced by melanocytes, which are found in the stratum basale of the epidermis. Although human beings generally possess a similar concentration of melanocytes in their skin, the melanocytes in some individuals and ethnic groups more frequently or less frequently express the melanin-producing genes, thereby conferring a greater or lesser concentration of skin melanin. Some individual animals and humans have very little or no melanin in their bodies, a condition known as albinism.
Because melanin is an aggregate of smaller component molecules, there are a number of different types of melanin with differing proportions and bonding patterns of these component molecules. Both pheomelanin and eumelanin are found in human skin and hair, but eumelanin is the most abundant melanin in humans, as well as the form most likely to be deficient in albinism.
Eumelanin polymers have long been thought to comprise numerous cross-linked 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) polymers; recent research into the electrical properties of eumelanin, however, has indicated that it may consist of more basic oligomers adhering to one another by some other mechanism. Thus, the precise nature of eumelanin's molecular structure is once again the object of study.[citation needed] Eumelanin is found in hair and skin, and colors hair grey, black, yellow, and brown. In humans, it is more abundant in peoples with dark skin. There are two different types of eumelanin, which are distinguished from each other by their pattern of polymer bonds. The two types are black eumelanin and brown eumelanin, with black melanin being darker than brown. Black eumelanin is in mostly non-Europeans and aged Europeans, while brown eumelanin is in mostly young Europeans. A small amount of black eumelanin in the absence of other pigments causes grey hair. A small amount of brown eumelanin in the absence of other pigments causes yellow (blond) color hair.
Pheomelanin is also found in hair and skin and is both in lighter skinned humans and darker skinned humans. In general women have more pheomelanin than men, and thus women's skin is generally redder than men's. Pheomelanin imparts a pink to red hue and, thus, is found in particularly large quantities in red hair. Pheomelanin is particularly concentrated in the lips, nipples, glans of the penis, and vagina.[4] Pheomelanin also may become carcinogenic when exposed to the ultraviolet rays of the sun. Chemically, pheomelanin differs from eumelanin in that its oligomer structure incorporates benzothiazine units which are produced instead of DHI and DHICA when the amino acid L-cysteine is present.
Neuromelanin is the dark pigment present in pigment bearing neurons of four deep brain nuclei: the substantia nigra (in Latin, literally "black substance") - Pars Compacta part, the locus ceruleus ("blue spot"), the dorsal motor nucleus of the vagus nerve (cranial nerve X), and the median raphe nucleus of the pons. Both the substantia nigra and locus ceruleus can be easily identified grossly at the time of autopsy due to their dark pigmentation. In humans, these nuclei are not pigmented at the time of birth, but develop pigmentation during maturation to adulthood. Although the functional nature of neuromelanin is unknown in the brain, it may be a byproduct of the synthesis of monoamine neurotransmitters for which the pigmented neurons are the only source. The loss of pigmented neurons from specific nuclei is seen in a variety of neurodegenerative diseases. In Parkinson's disease there is massive loss of dopamine producing pigmented neurons in the substantia nigra. A common finding in advanced Alzheimer's disease is almost complete loss of the norepinephrine producing pigmented neurons of the locus ceruleus. Neuromelanin has been detected in primates and in carnivores such as cats and dogs.LA

SKINPIGMENTS

INTRODUCTION

Various shades and colors of human skin are created by the brown pigment, melanin. Without melanin, the skin would be pale white with varying shades of pink caused by the blood flowing through it. Fair-skinned people produce very little melanin; darker-skinned people produce moderate amounts; and very dark skinned people produce a great deal. People with albinism have no melanin.
Melanin is produced by special cells (melanocytes) that are interspersed among the other cells in the top layer of the skin, the epidermis. After melanin is produced, it spreads into other nearby skin cells.
When exposed to sunlight, melanocytes produce increased amounts of melanin, causing the skin to darken, or tan. In some fair-skinned people, certain melanocytes produce more melanin than others in response to sunlight. This uneven melanin production results in spots of pigmentation known as freckles. A tendency to freckles runs in families. Increased amounts of melanin can also occur in response to hormonal changes, such as those that may take place in Addison's disease, in pregnancy, or with oral contraceptive use. Some cases of skin darkening, however, are not related to increased melanin at all, but rather to abnormal pigments that make their way into the skin. Diseases such as hemochromatosis or hemosiderosis or some drugs that are applied to the skin, swallowed, or injected can cause skin darkening. A buildup of bilirubin (the main pigment in bile) causes the skin to turn yellow (jaundice).
An abnormally low amount of melanin (hypopigmentation) may affect large areas of the body or small patches. Decreased melanin usually results from a previous injury to the skin such as a blister, ulcer, burn, or skin infection. Sometimes pigment loss results from an inflammatory condition of the skin or, in rare instances, is hereditary. A common skin infection, tinea versicolor BACTIRIAL SKIN DISORDERS

The skin provides a remarkably good barrier against bacterial infections. Although many bacteria come in contact with or reside on the skin, they are normally unable to establish an infection. When bacterial skin infections do occur, they can range in size from a tiny spot to the entire body surface. They can range in seriousness as well, from harmless to life threatening.
Many types of bacteria can infect the skin. The most common are Staphylococcus and Streptococcus. Skin infections caused by less common bacteria may develop in people while hospitalized or living in a nursing home, while gardening, or while swimming in a pond, lake, or ocean.
Some people are at particular risk of contracting skin infections. For example, people with diabetes are likely to have poor blood flow, especially to the hands and feet, and the high levels of sugar in their blood decrease the ability of white blood cells to fight infections. People with human immunodeficiency virus (HIV) or AIDS or other immune disorders and those undergoing chemotherapy are at higher risk as well, because they have a weakened immune system. Skin that is inflamed or damaged by sunburn, scratching, or other trauma is more likely to be infected. In fact, any break in the skin predisposes a person to infection.
Prevention involves keeping the skin undamaged and clean. When the skin is cut or scraped, the injury should be washed with soap and water and covered with a sterile bandage. Antibiotic creams and ointments may be applied to open areas to keep the tissue moist and to try to prevent bacterial invasion. If an infection develops, small areas may be treated with antibiotic creams. Larger areas require antibiotics taken by mouth or given by injection. Abscesses (pus-filled pockets) should be cut open by the doctor and allowed to drain, and any dead tissue must be surgically removed.

major classes of peptides;

Here are the major classes of peptides, according to how they are produced:
Ribosomal peptides
Are synthesized by translation of mRNA. They are often subjected to proteolysis to generate the mature form. These function, typically in higher organisms, as hormones and signaling molecules. Some organisms produce peptides as antibiotics, such as microcins.

[1] Since they are translated, the amino acid residues involved are restricted to those utilized by the ribosome. However, these peptides frequently have posttranslational modifications, such as phosphorylation, hydroxylation, sulfonation, palmitylation, glycosylation and disulfide formation. In general, they are linear, although lariat structures have been observed.

[2] More exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom

.[3]
Nonribosomal peptides
These peptides are assembled by enzymes that are specific to each peptide, rather than by the ribosome. The most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms.[4] Other nonribosomal peptides are most common in unicellular organisms, plants, and fungi and are synthesized by modular enzyme complexes called nonribosomal peptide synthetases.[5] These complexes are often laid out in a similar fashion, and they can contain many different modules to perform a diverse set of chemical manipulations on the developing product.[6] These peptides are often cyclic and can have highly-complex cyclic structures, although linear nonribosomal peptides are also common. Since the system is closely related to the machinery for building fatty acids and polyketides, hybrid compounds are often found. Oxazoles, thiazoles often indicate that the compound was synthesized in this fashion.[7]
Peptones
See also Tryptone
Are derived from animal milk or meat digested by proteolytic digestion. In addition to containing small peptides, the resulting spray-dried material includes fats, metals, salts, vitamins and many other biological compounds. Peptone is used in nutrient media for growing bacteria and fungi.[8]
Peptide Fragments
Refer to fragments of proteins that are used to identify or quantify the source protein.[9] Often these are the products of enzymatic degradation performed in the laboratory on a controlled sample, but can also be forensic or paleontological samples which have been degraded by natural effects.[10][11]

Peptides in molecular biology
Peptides have received prominence in molecular biology in recent times for several reasons. The first and most important is that peptides allow the creation of peptide antibodies in animals without the need to purify the protein of interest.[12] This involves synthesizing antigenic peptides of sections of the protein of interest. These will then be used to make antibodies in a rabbit or mouse against the protein.
Another reason is that peptides have become instrumental in mass spectrometry, allowing the identification of proteins of interest based on peptide masses and sequence. In this case the peptides are most often generated by in-gel digestion after electrophoretic separation of the proteins.
Peptides have recently been used in the study of protein structure and function. For example, synthetic peptides can be used as probes to see where protein-peptide interactions occur.
Inhibitory peptides are also used in clinical research to examine the effects of peptides on the inhibition of cancer proteins and other diseases.

Well-known peptide families in humans
The peptide families in this section are all ribosomal peptides, usually with hormonal activity. All of these peptides are synthesized by cells as longer "propeptides" or "proproteins" and truncated prior to exiting the cell. They are released into the bloodstream where they perform their signalling functions.

The Tachykinin peptides
Substance P
Kassinin
Neurokinin A
Eledoisin
Neurokinin B

Vasoactive intestinal peptides
VIP (Vasoactive Intestinal Peptide; PHM27)
PACAP Pituitary Adenylate Cyclase Activating Peptide
Peptide PHI 27 (Peptide Histidine Isoleucine 27)
GHRH 1-24 (Growth Hormone Releasing Hormone 1-24)
Glucagon
Secretin

Pancreatic polypeptide-related peptides
NPY
PYY (Peptide YY)
APP (Avian Pancreatic Polypeptide)
PPY Pancreatic PolYpeptide

Opioid peptides
Proopiomelanocortin (POMC) peptides
Enkephalin pentapeptides
Prodynorphin peptides

Calcitonin peptides
Calcitonin
Amylin
AGG01

Other peptides
B-type Natriuretic Peptide (BNP) - produced in myocardium & useful in medical diagnosis

Notes on terminology
A polypeptide is a single linear chain of amino acids.
A protein is one or more polypeptides more than about 50 amino acids long.
An oligopeptide or (simply) a peptide is a polypeptide less than 30-50 amino acids long.
A dipeptide has two amino acids.
A tripeptide has three amino acids.
A pentapeptide has five amino acids.
An octapeptide has eight amino acids. (e.g., angiotensin II.
A nonapeptide has nine amino acids (e.g., oxytocin).
A decapeptide has ten amino acids (e.g., gonadotropin-releasing hormone & angotensin I).
A neuropeptide is a peptide that is active in association with neural tissue.
A peptide hormone is a peptide that acts as a hormone.

See also
Peptidomimetics (such as peptoids and β-peptides) to peptides, but with different properties.
bis-peptide
Peptide synthesis
Translation
Ribosome
Argireline

peptides

Ribosomal peptides
Are synthesized by translation of mRNA. They are often subjected to proteolysis to generate the mature form. These function, typically in higher organisms, as hormones and signaling molecules. Some organisms produce peptides as antibiotics, such as microcins.[1] Since they are translated, the amino acid residues involved are restricted to those utilized by the ribosome. However, these peptides frequently have posttranslational modifications, such as phosphorylation, hydroxylation, sulfonation, palmitylation, glycosylation and disulfide formation. In general, they are linear, although lariat structures have been observed.[2] More exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom.[3]
Nonribosomal peptides
These peptides are assembled by enzymes that are specific to each peptide, rather than by the ribosome. The most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms.[4] Other nonribosomal peptides are most common in unicellular organisms, plants, and fungi and are synthesized by modular enzyme complexes called nonribosomal peptide synthetases.[5] These complexes are often laid out in a similar fashion, and they can contain many different modules to perform a diverse set of chemical manipulations on the developing product.[6] These peptides are often cyclic and can have highly-complex cyclic structures, although linear nonribosomal peptides are also common. Since the system is closely related to the machinery for building fatty acids and polyketides, hybrid compounds are often found. Oxazoles, thiazoles often indicate that the compound was synthesized in this fashion.[7]
Peptones
See also Tryptone
Are derived from animal milk or meat digested by proteolytic digestion. In addition to containing small peptides, the resulting spray-dried material includes fats, metals, salts, vitamins and many other biological compounds. Peptone is used in nutrient media for growing bacteria and fungi.[8]
Peptide Fragments
Refer to fragments of proteins that are used to identify or quantify the source protein.[9] Often these are the products of enzymatic degradation performed in the laboratory on a controlled sample, but can also be forensic or paleontological samples which have been degraded by natural effects.[10][11]

[edit] Peptides in molecular biology
Peptides have received prominence in molecular biology in recent times for several reasons. The first and most important is that peptides allow the creation of peptide antibodies in animals without the need to purify the protein of interest.[12] This involves synthesizing antigenic peptides of sections of the protein of interest. These will then be used to make antibodies in a rabbit or mouse against the protein.
Another reason is that peptides have become instrumental in mass spectrometry, allowing the identification of proteins of interest based on peptide masses and sequence. In this case the peptides are most often generated by in-gel digestion after electrophoretic separation of the proteins.
Peptides have recently been used in the study of protein structure and function. For example, synthetic peptides can be used as probes to see where protein-peptide interactions occur.
Inhibitory peptides are also used in clinical research to examine the effects of peptides on the inhibition of cancer proteins and other diseases.

[edit] Well-known peptide families in humans
The peptide families in this section are all ribosomal peptides, usually with hormonal activity. All of these peptides are synthesized by cells as longer "propeptides" or "proproteins" and truncated prior to exiting the cell. They are released into the bloodstream where they perform their signalling functions.

[edit] The Tachykinin peptides
Substance P
Kassinin
Neurokinin A
Eledoisin
Neurokinin B

[edit] Vasoactive intestinal peptides
VIP (Vasoactive Intestinal Peptide; PHM27)
PACAP Pituitary Adenylate Cyclase Activating Peptide
Peptide PHI 27 (Peptide Histidine Isoleucine 27)
GHRH 1-24 (Growth Hormone Releasing Hormone 1-24)
Glucagon
Secretin

[edit] Pancreatic polypeptide-related peptides
NPY
PYY (Peptide YY)
APP (Avian Pancreatic Polypeptide)
PPY Pancreatic PolYpeptide

[edit] Opioid peptides
Proopiomelanocortin (POMC) peptides
Enkephalin pentapeptides
Prodynorphin peptides

[edit] Calcitonin peptides
Calcitonin
Amylin
AGG01

[edit] Other peptides
B-type Natriuretic Peptide (BNP) - produced in myocardium & useful in medical diagnosis

[edit] Notes on terminology
A polypeptide is a single linear chain of amino acids.
A protein is one or more polypeptides more than about 50 amino acids long.
An oligopeptide or (simply) a peptide is a polypeptide less than 30-50 amino acids long.
A dipeptide has two amino acids.
A tripeptide has three amino acids.
A pentapeptide has five amino acids.
An octapeptide has eight amino acids. (e.g., angiotensin II.
A nonapeptide has nine amino acids (e.g., oxytocin).
A decapeptide has ten amino acids (e.g., gonadotropin-releasing hormone & angotensin I).
A neuropeptide is a peptide that is active in association with neural tissue.
A peptide hormone is a peptide that acts as a hormone.

[edit] See also
Peptidomimetics (such as peptoids and β-peptides) to peptides, but with different properties.
bis-peptide
Peptide synthesis
Translation
Ribosome
Argireline

[edit] References
^ Duquesne S, Destoumieux-Garzón D, Peduzzi J, Rebuffat S (2007). "Microcins, gene-encoded antibacterial peptides from enterobacteria". Natural product reports 24 (4): 708–34. doi:10.1039/b516237h. PMID 17653356.
^ Pons M, Feliz M, Antònia Molins M, Giralt E (1991). "Conformational analysis of bacitracin A, a naturally occurring lariat". Biopolymers 31 (6): 605–12. doi:10.1002/bip.360310604. PMID 1932561.
^ Torres AM, Menz I, Alewood PF, et al (2002). "D-Amino acid residue in the C-type natriuretic peptide from the venom of the mammal, Ornithorhynchus anatinus, the Australian platypus". FEBS Lett. 524 (1-3): 172–6. doi:10.1016/S0014-5793(02)03050-8. PMID 12135762.
^ Meister A, Anderson M (1983). "Glutathione". Annu Rev Biochem 52: 711 – 60. doi:10.1146/annurev.bi.52.070183.003431. PMID 6137189.
^ Hahn M, Stachelhaus T (2004). "Selective interaction between nonribosomal peptide synthetases is facilitated by short communication-mediating domains". Proc. Natl. Acad. Sci. U.S.A. 101 (44): 15585–90. doi:10.1073/pnas.0404932101. PMID 15498872.
^ Finking R, Marahiel MA (2004). "Biosynthesis of nonribosomal peptides1". Annu. Rev. Microbiol. 58: 453–88. doi:10.1146/annurev.micro.58.030603.123615. PMID 15487945.
^ Du L, Shen B (2001). "Biosynthesis of hybrid peptide-polyketide natural products". Current opinion in drug discovery & development 4 (2): 215–28. PMID 11378961.
^ Payne JW (1976). "Peptides and micro-organisms". Adv. Microb. Physiol. 13: 55–113. PMID 775944.
^ Hummel J, Niemann M, Wienkoop S, et al (2007). "ProMEX: a mass spectral reference database for proteins and protein phosphorylation sites". BMC Bioinformatics 8: 216. doi:10.1186/1471-2105-8-216. PMID 17587460.
^ Webster J, Oxley D (2005). "Peptide mass fingerprinting: protein identification using MALDI-TOF mass spectrometry". Methods Mol. Biol. 310: 227–40. PMID 16350956.
^ Marquet P, Lachâtre G (1999). "Liquid chromatography-mass spectrometry: potential in forensic and clinical toxicology". J. Chromatogr. B Biomed. Sci. Appl. 733 (1-2): 93–118. doi:10.1016/S0378-4347(99)00147-4. PMID 10572976.

VACCINE

For other uses, see Vaccine (disambiguation).
A vaccine is a biological preparation which is used to establish or improve immunity to a particular disease.
Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine).

Name and history
The term "vaccine" derives from Edward Jenner's 1796 use of cowpox (Latin variolæ vaccinæ, adapted from the Latin vaccīn-us, from vacca cow), which, when administered to humans, provided them protection against smallpox. The earliest vaccines were based on the concept of variolation originating in China, in which a person is deliberately infected with a weak form of smallpox as a form of inoculation. Jenner realized that milkmaids who had contact with cowpox did not get smallpox. The process of distributing and administrating vaccines is thus referred to as "vaccination" .
Jenner's work was continued by Louis Pasteur and others in the 19th century. Since vaccination against smallpox was much safer than smallpox inoculation, the latter fell into disuse and was eventually banned in England in 1849.
The 19th and 20th centuries saw the introduction of several successful vaccines against a number of infectious diseases. These included bacterial and viral diseases, but not (to date) any parasitic diseases.

Types

Avian Flu vaccine development by reverse genetics techniques.
Vaccines may be dead or inactivated organisms or purified products derived from them.
There are four types of traditional vaccines:[1]
Vaccines containing killed microorganisms - these are previously virulent micro-organisms which have been killed with chemicals or heat. Examples are vaccines against flu, cholera, bubonic plague, and hepatitis A.
Vaccines containing live, attenuated virus microorganisms - these are live micro-organisms that have been cultivated under conditions that disable their virulent properties or which use closely-related but less dangerous organisms to produce a broad immune response. They typically provoke more durable immunological responses and are the preferred type for healthy adults. Examples include yellow fever, measles, rubella, and mumps. The live tuberculosis vaccine is not the contagious strain, but a related strain called "BCG"; it is used in the United States very infrequently.
Toxoids - these are inactivated toxic compounds in cases where these (rather than the micro-organism itself) cause illness. Examples of toxoid-based vaccines include tetanus and diphtheria. Not all toxoids are for micro-organisms; for example, Crotalis atrox toxoid is used to vaccinate dogs against rattlesnake bites.
Subunit - rather than introducing an inactivated or attenuated micro-organism to an immune system (which would constitute a "whole-agent" vaccine), a fragment of it can create an immune response. Characteristic examples include the subunit vaccine against HBV that is composed of only the surface proteins of the virus (produced in yeast) and the virus-like particle (VLP) vaccine against human papillomavirus (HPV) that is composed of the viral major capsid protein.
A number of innovative vaccines are also in development and in use:
Conjugate - certain bacteria have polysaccharide outer coats that are poorly immunogenic. By linking these outer coats to proteins (e.g. toxins), the immune system can be led to recognize the polysaccharide as if it were a protein antigen. This approach is used in the Haemophilus influenzae type B vaccine.
Recombinant Vector - by combining the physiology of one micro-organism and the DNA of the other, immunity can be created against diseases that have complex infection processes
DNA vaccination - in recent years a new type of vaccine, created from an infectious agent's DNA called DNA vaccination, has been developed. It works by insertion (and expression, triggering immune system recognition) into human or animal cells, of viral or bacterial DNA. Some cells of the immune system that recognize the proteins expressed will mount an attack against these proteins and cells expressing them. Because these cells live for a very long time, if the pathogen that normally expresses these proteins is encountered at a later time, they will be attacked instantly by the immune system. One advantage of DNA vaccines is that they are very easy to produce and store. As of 2006, DNA vaccination is still experimental.
While most vaccines are created using inactivated or attenuated compounds from micro-organisms, synthetic vaccines are composed mainly or wholly of synthetic peptides, carbohydrates or antigens.
Vaccines may be monovalent (also called univalent) or multivalent (also called polyvalent). A monovalent vaccine is designed to immunize against a single antigen or single microorganism.[2] A multivalent or polyvalent vaccine is designed to immunize against two or more strains of the same microorganism, or against two or more microorganisms.[3]

[edit] Developing immunity
The immune system recognizes vaccine agents as foreign, destroys them, and 'remembers' them. When the virulent version of an agent comes along the body recognises the protein coat on the virus, and thus is prepared to respond, by (1) neutralizing the target agent before it can enter cells, and (2) by recognizing and destroying infected cells before that agent can multiply to vast numbers.
Vaccines have contributed to the eradication of smallpox, one of the most contagious and deadly diseases known to man. Other diseases such as rubella, polio, measles, mumps, chickenpox, and typhoid are nowhere near as common as they were just a hundred years ago. As long as the vast majority of people are vaccinated, it is much more difficult for an outbreak of disease to occur, let alone spread. This effect is called herd immunity. Polio, which is transmitted only between humans, is targeted by an extensive eradication campaign that has seen endemic polio restricted to only parts of four countries.[2] The difficulty of reaching all children as well as cultural misunderstandings, however, have caused the eradication date to be missed several times.

[edit] Schedule
Main article: Vaccination schedule
See also: Vaccination policy
In order to provide best protection, children are recommended to receive vaccinations as soon as their immune systems are sufficiently developed to respond to particular vaccines, with additional 'booster' shots often required to achieve 'full immunity'. This has led to the development of complex vaccination schedules. In the United States, the Advisory Committee on Immunization Practices, which recommends schedule additions for the Center for Disease Control, recommends routine vaccination of children against: hepatitis A, hepatitis B, polio, mumps, measles, rubella, diphtheria, pertussis, tetanus, HiB, chicken pox, rotavirus, influenza, meningococcal disease and pneumonia. The large number of vaccines and boosters recommended (up to 24 injections by age two) has led to problems with achieving full compliance. In order to combat declining compliance rates, various notification systems have been instituted and a number of combination injections are now marketed (e.g., Prevnar and ProQuad vaccines), which provide protection against multiple diseases.
Besides recommendations for infant vaccinations and boosters, many specific vaccines are recommended at other ages or for repeated injections throughout life -- most commonly for measles, tetanus, influenza, and pneumonia. Pregnant women are often screened for continued resistance to rubella. The human papillomavirus vaccine is currently recommended in the U.S. and UK for ages 11–25. Vaccine recommendations for the elderly concentrate on pneumonia and influenza, which are more deadly to that group. In 2006, a vaccine was introduced against shingles, a disease caused by the chicken pox virus, which usually affects the elderly.
In Australia, a massive increase in vaccination rates was observed when the federal government made certain benefits (such as the universal 'Family Allowance' welfare payments for parents of children) dependent on vaccination. As well, children were not allowed into school unless they were either vaccinated or their parents completed a statutory declaration refusing to immunize them, after discussion with a doctor, and other bureaucracy. (Similar school-entry vaccination regulations have been in place in some parts of Canada for several years.) It became easier and cheaper to vaccinate one's children than not to. When faced with the annoyance, many more casual objectors simply gave in.[citation needed]

[edit] Efficacy
Vaccines do not guarantee complete protection from a disease. Sometimes this is because the host's immune system simply doesn't respond adequately or at all. This may be due to a lowered immunity in general (diabetes, steroid use, HIV infection) or because the host's immune system does not have a B-cell capable of generating antibodies to that antigen.
Even if the host develops antibodies, the human immune system is not perfect and in any case the immune system might still not be able to defeat the infection.
Adjuvants are typically used to boost immune response. Adjuvants are sometimes called the dirty little secret of vaccines [3] in the scientific community, as not much is known about how adjuvants work. Most often aluminium adjuvants are used, but adjuvants like squalene are also used in some vaccines and more vaccines with squalene and phosphate adjuvants are being tested. The efficacy or performance of the vaccine is dependent on a number of factors:
the disease itself (for some diseases vaccination performs better than for other diseases)
the strain of vaccine (some vaccinations are for different strains of the disease) [4]
whether one kept to the timetable for the vaccinations (see Vaccination schedule)
some individuals are 'non-responders' to certain vaccines, meaning that they do not generate antibodies even after being vaccinated correctly
other factors such as ethnicity or genetic predisposition
When a vaccinated individual does develop the disease vaccinated against, the disease is likely to be milder than without vaccination.
The following are important considerations in the effectiveness of a vaccination program:[citation needed]
careful modelling to anticipate the impact that an immunisation campaign will have on the epidemiology of the disease in the medium to long term
ongoing surveillance for the relevant disease following introduction of a new vaccine and
maintaining high immunisation rates, even when a disease has become rare.
In 1958 there were 763,094 cases of measles and 552 deaths in the United States.[4][5] With the help of new vaccines, the number of cases dropped to fewer than 150 per year (median of 56).[5] In early 2008, there were 64 suspected cases of measles. 54 out of 64 infections were acquired outside of the United States, and 63 of 64 either had never been vaccinated against measles, or were uncertain whether they had been vaccinated.[5]

Serum Free Media -ADVANTAGE

Serum Free Media

-In view of the disadvantages due to serum, extensive investigations have been made to develop serum-free formulations of culture media. These efforts were mainly based on the following three approaches:

(1) analytical approach based on the analysis of serum constituents,

(2) synthetic approach to supplement basal media by various combinations of growth factors, and
(3) limiting factor approach consisting of lowering the serum level in the medium till growth stops and then supplementing the medium with vitamins, amino acids, hormones, etc. till growth resumes.These approaches have resulted in several elaborate media formulations in which serum in sought to be replaced by a mixture of amino acids, vitamins, several other organic compounds, etc.; hormones, growth factors and other proteins are supplemented when required. However, addition of 5-20% of serum even in these media is essential for optimum growth.

Advantages of Serum Free Media

- 1.

Improved reproducibility of results from different laboratories and over time since variation due to batch change of serum is avoided.

2. Easier downstream processing of products from cultured cells.

3. Toxic effects of serum are avoided.

4. Biassays are free from interference due to serum proteins.

5. There is no danger of degradation of sensitive proteins by serum proteases.

6. They permit selective culture of differentiated and producing cell types from the heterogenous cultures.