How Do Bacteria, Animals and Plants Adapts to Stress?

Both prokaryotic and eukaryotic cell quickly responds to stress or damaging atimuli. In response to a range of different stress , including heat shock , nutrients deprivation, and metabolic disruption, cells synthesize about two dozen different proteins (called stress proteins) .The most thoroughly studied stress is heat shock, in which a sudden increase in temperature includes the synthesis of a group of proteins. Genes that are responsible for the synthesis of heat shock proteins are among the most evolutionarily conserved genetics system s known. They are very similar in amino acid sequence in both prokaryotes and eukaryotes. Heat shock proteins accumulate to very high level in stress cells, accounting for as much as 15% of the total protein in E.coli.

The function of several of the heat shock protein is beginning to be understood. Most of these proteins are synthesized at low levels under normal growth conditions and play a vital role in protecting the cell from the damaging effects of heat and other stresses. The heat shock proteins hsp70 and hsp60 (the number refers to the molecular weight of the protein times 1000) are involved in assembly or disassembly of protein complexes.

Hsp70 is involved in translocating certain proteins trough intracellular membranes and binds to DNA replication complexes. Hsp60 has been found to interact with steroid hormone receptors. In plats hsps60 interacts with what may be the most abundant protein in the biosphere, ribulose-1,5-bisphosphate carboxylase-oxygenase, an enzyme that fixes CO2 in chloroplasts.

An amazing example of the use of heat shock proteins for protection in found in the desert- dwelling ant Cataglyphis bombycina , which is perfectly suited for life in the Sahara desert. Cataglyphis bombycina anticipates the high temperature of up to 1400 F found in the desert sand by producing heat shock proteins in abundance, even when in underground nests. These proteins seem to protect them to their natural conditions, grinding them up , and finding copious quantities of the heat shock proteins : a primitive strike against the searing temperatures.

Invading organisms also can produce stress proteins in the host. This can be detrimental because some of these proteins in the host. This can be deter mental because some of these proteins are very similar to the host’s stress proteins and create an autoimmune disease in the host’s organism. For example, researchers have shown that the hsp60 proteins from tuberculosis bacterial and human cells are sufficiently similar that they are they both recognized by antibodies from a tuberculosis patient.. Thus , a bacterial invasion may induce the body’s immune system to make antibodies to the stress protein of the bacteria, and these antibodies to the stress proteins of the bacteria, and these antibodies may also attack some of the body’s own vital proteins. It is believed that this may be the development process of some forms of chronic rheumatoid arthritis, which is an inflammation of the synovial membranes of joints.

Many Natural Product Are Mutagenic

In recent years, we have heard more and more about how our diet affect our health , especially in relation to the production of cancers. Research has shown that our diet contains an enormous variety of natural mutagens and carcinogens. It is also apparent that we are ingesting vastly greater qualities of these substances than was previously suspected. Perhaps this natural chemical product should be primary concern rather than the mutagenicity of industrial chemicals, food additives and pollutants in our environment. For example, in 1989 the United States had a big publicity –generated scare concerning the plant growth regulator Alar, which is used to delay ripening of apples so that they do not drop prematurely. Alar was said to be carcinogenic, but when put in perspective with chemicals in our daily diets , it does not to be so bad. For instance, the hydrazines in a helping of mushrooms are 60 times more carcinogenic than the Alar consumed in a glass of apple juice or 20 times greater than a daily peanut butter sandwich, which frequently contains aflatoxin B. Our diets contain literally millions of natural chemicals; intact it is not practical to test them all for carcinogenicity.

Animal tests and the and the Ames test have been used to evaluate cooked foods for their potential for inducing cancers; and it has been found that browed sugars or breads contains a variety of mutagens. In addition, caffeine and its close relative theobromine found in coffee, tea, cocoa, and some soft drinks may increase the risk of tumors by inhibiting DNA repair enzymes. Plants synthesize many carcinogenic or teratogenic chemicals as delense mechanism to ward off the animals that want to consume them. Examples of plants plant carcinogens include psoralen and its derivatives, which are widespread in plants and have been used as sunscreen in France; solanine and chaconine are teratogens and are found in greened potatoes. Other food that contains natural cicargens includes banana, basil, broccoli, cabbage, cauliflower, celery, horseradish, mustard turnips, and black pepper. In addition, red wines are believed to be responsible for the high incidence of stomach cancers among the French people, although red wine also seems to decrease the incidence of coronary heart disease. It seems that nothing can be consumed that does not contain mutagen!

Another big problem with American diet is the consumption of excess quantities of fats. The average American consumes 40% of her/ his calories in the form of fat. Comparisons of cancer death rates in different national populations have provided important clues to the nutrational causes of cancer. Very different types of cancers appear in the United States than appear in Japan. In United States, colon, breast, and prostate cancer are most prevalent, whereas stomach cancers are in excess in Japan. When the amount of dietary fat intake is plotted against the number of death by breast cancer, the results are striking; the more fat in the diet, the more higher the rate of breast cancer. How might fat intake cause cancer? It may be caused by rancid fat because it represents a sizable percentage of the fat are very prone to oxidation, which produces a variety of carcinogenic compounds. Another likely explanation is that may carcinogens are soluble in fats and accumulate in the fat of the animals we eat.

Not all Enzymatic Reactions Are Catalyzed by Protein

It had been a firmly established belief in biology that catalysis is reserved for proteins. However in 1989 the Nobel Prize was presented to Sidney Altman and Tomas Cech for discovering that RNA can catalyze a reaction. In respect, catalytic RNA make s a lot of sense. This is based on the old question regarding the origin of life, which comes first, enzyme that do the work of the cell or nucleic acids that carry the information required to produce the enzymes ? Nucleic acids as catalysts circumvents this problem.

Research leading to the discovery that RNA can act as a catalyst started in the 1970’s. Thomas Cech , at the university of Colorado at Boulder, was studying the excision of introns in a ribosomal RNA gene in Tetrahymena thermophila. In attempting to purify the enzyme responsible for splicing reaction, he instead found , much of his amazement , that intron could be spliced –out in the absence of any added cell extract. Much as they tried, Cech and his colleagues could not identify any protein associated with the splicing reaction,. After much work , Cech proposed that the intron sequence portion of the RNA had properties of an enzyme enabling it to break and reform phosphodiester bonds. At about the same time, Sidney Altman, who is a Professor at Yale university was studying the way tRNA molecules are processed in the cell when he and his colleagues isolated a enzymes called RNase-P, which is responsible for conversion of a precursor tRNA into the active tRNA. Much of their surprise, they found that RNase-P contained RNA in addition to protein and that RNA was an essential component of the active enzyme. This was such a foreign idea that they had difficulty publishing their findings. The following year, Altman Demonstrated the final bit of evidence establishing that RNA can act as a catalyst by showing that the RNase-P RNA submit could catalyze the cleavage of precursor tRNA into active tRNA in the absence of the protein component.

Since Cech’s and Altman’s discovery, other investigators have discovered other example of self-cleaving RNA sot catalytic RNA molecules dubbed ribozymes have either a hairpin – or hammerhead – shaped active center and a unique secondary structure allowing them to cleave other RNA molecules at specific sequences. It is possible to produce in the laboratory ribozymes that will specifically cleave my RNA molecule. These RNA catalysts may have pharmaceuticals applications. For example , a ribozyme has been designed to cleave the RNA of HIV. By placing a ribozyme in the cell all incoming virus particles that express this particular gene will have the RNA product cleaved by the ribozyme, which ,in the end would kill all invading virus particles.

Introducing DNA Safeguarding

The most recent statistics available tell a terrible story. More than 58,000 children are abducted by non-family members annually. While no one can fully guarantee your child's safety, DNA Safeguarding for children will keep you prepared should such a tragedy strike. DNA Safeguarding, in addition to traditional methods of identifying a child, is a superior way to identify and locate your child using their DNA sample. Unlike photos, your child's DNA will remain consistent throughout their lifetime.

With DNA Safeguarding, you are guaranteed that your child's DNA is properly stored under ideal conditions. Our staff is well trained in the proper storage and security of your child's DNA, ensuring the sample will be usable should an emergency occur.

For your investment of $95, you will receive the Peace of Mind that comes with protecting your child. You will also receive a handy identification card to keep in your wallet, providing you with quick and easy access to IDENTIGENE's toll-free number should an emergency arise. In addition, you will also receive a customized DNA Safeguarding certificate with your child's name and safeguarding number, ideal for storing with your child's important documents. You will receive the identification card and certificate within four weeks of sending your child's sample to Identigene.

How DNA Safeguarding works:

- Collect your child's DNA sample in the privacy of your home using the simple cotton cheek swab provided.

- Mail your DNA sample to IDENTIGENE in the envelope provided.

- Your child's DNA sample will be preserved in a secure, climate-controlled facility.

- You will receive an identification card with IDENTIGENE's toll-free number should an emergency arise.

- You will also receive a DNA Safeguarding certificate with your child's name and safeguarding number, as well as our full contact information.

DNA Safeguarding can allow your child's DNA sample to be compared against evidence samples to assist in tracking your child's location, possibly aiding in the safe return of your child.

Human Behavior : Genetics & Environment

Most individuals readily accepts that physical human characteristics such as hair color, skin color and height are controlled by genes. How ever the question of the importance of the genetic and environment all factor in the control of human psychological characteristics, such as behavior and intelligence, is more controversial. This question has a long history and is often referred to as the Nature vs Nature controversy. The question I s not whether the genotype has any effect; clearly genotype and environment both influence personality and behavior . The questions are how largely a contribution each make and which is the dominant influence. In Western society, the prevailing opinion has long been that behavior is most strongly influenced by environment. This implies that personality disorder has its cause in childhood experience. And societal influences, not in the genome. This controversy is hard to test scientifically because doing quantities genetics studies of human behavior is difficult. Large scale experiment involving controlled human mating cannot be made, nor is it possible to control the environment of human population. It is possible, however to study cases in which humans with identical genotypes are exposed to different environment by studying cases of monozygotic twins who have the same genotype in principle, all difference in behavior characteristics is for environmental influences, whereas similarities may result from genetic influences.

T.J Bouchard at the University of Minnesota performed an important twin study . Science 1979, Bouchrd has studied over 1000 pairs of monozygotic twins raised together(MZT) or raised apart (MZA). Twins participating in the study undergo over 50 hours of intelligence and psychological testing, the result suggest that genetics has large influences on intelligence and behavior. Calculation of H2 for IQ, for example suggest that more than 70% of the variance in IQ can be traced to genetics. Comparing MZA with MZT suggest that being reared together actually has only a minor effect on IQ . The together ness factor was more pronounced in childhood and early adolescence but declined greatly during adulthood.

Some of the most interesting result came from test measuring personality and behavior characteristics. For Characteristics such as aptitude , leisure time activities and vocational interest the twins showed a strong genetic influence, as largely as for IQ. No aspect of behavior was unaffected . Overall ,the genetics influence on all behavioral characteristics was been 50 and 70%. Major personality disorder (manic depression) also have significant genetic basis.

Individual study cases cannot be the basis for a strong conclusion. But taken together , the many cases suggest that genotypic differences may account for many, or even a majority of, the difference in behavior between individuals in human populations, including behaviors normally assumes to be under conscious control. It is becoming clear that the brain ,like other organs of the body , is strongly influenced by the genotype, and these influences may shape our behavior to a much greater extent than was previously believed.