In the form of microbial sex called transformation ...

Bacteria acquire resistance genes in three directions. A. A spontaneous mutation, DNA bacteria can change spontaneously, as indicated in star formation. Drug-resistant tuberculosis arises this way. 2. In the form of microbial sex called transformation, one bacterium can take up DNA from another. Gonorrhea resistant to penicillin (

) the results change. 3. Most frightening, however, the resistance acquired in a small circle of DNA called plasmids. Plasmids can buzz among bacteria of different species - they do not apply - and to some resistance. In 1968, 12,500 died in hvatemaltsiv epidemic diarrhea Shigella, caused by the parasite harboring plasmids that conferred resistance to four antibiotics! But bacteria do something much more clever than just mutated. This is risky because bacteria prefer to share the secrets of biochemical - resistance genes - that will enable them to resist or destroy antibiotics. This diabolical barter can occur in several ways. A. Plasmids - small fragments of DNA as a mini-chromosome - that exist outside the main chromosome. This exchange can jump wide units in bacterial phylogeny (

). It's almost as if a cow could provide genes crow and taught it growing teeth. 2. Gene cassettes

genes that may be linked to chromosomes (). Although the mechanism of this complex is comparable with a trip to the mall, says Davis. Genes called integrones code for enzymes called integrase, which can splice these cassettes in the chromosomes or other genetic material, where they become functional. It does something integrones features like shopping cart, says Davis. If bacteria can only resist, taking gene cassettes, then, as shoppers in the store video, not sure what they saw their first choice, the bacteria can pick up a few tapes and get some resistance to antibiotics. Besides, says Abigail Salyers microbiologist at the University of Illinois, "Bacteria also integrate resistance of disinfectants and contaminants in these clusters. Thus, the use of disinfectants or pollution can select for resistance to antibiotics that may be exactly what

found back in the beginning of our history. From the human point of view, the problem with this kind of resistance to its sustainability. Once lodged in chromosomes or plasmids, these resistance genes are distributed normal genes are daughters (

) cells. "The Origin and interstate spread of ... "In >> << gives a detailed picture of how the deadly bug that causes tuberculosis acquired resistance to many antibiotics. So far we have talked in general about resistance without painting a good idea of ​​how it works. And here we are in for another surprise, another sign that could be called a microbial mind. It appears that resistance to antibiotics is part of a broader picture of the way bacteria protect themselves against chemical threats in their environment.

It seems that these protective mechanisms is surprisingly similar to many kinds of organisms -. many threats "Question resistance converges with human infectious diseases and agricultural angles," says Joe Phytopathology Handelsman "or microbe is trying to protect themselves from antibiotics, fungicides, insecticides, herbicides, even of antiviral drugs. ". Handelsman, who studies the interaction between fungi and bacteria at the University of Wisconsin-Madison, shows more similarity "At the molecular level, there are few mechanisms of resistance: Change the target molecule, inactivation or spread of drugs or pesticides, sequester (

) or drug pesticides, or keep it in a cage "from the beginning. Overall, it makes sense that the microbes would defense. Finally, in the course of billions of years on the planet, they overcome the countless dangers of chemicals. But what is the source of resistance genes to antibiotics in the first place? Perhaps the organisms that initially produced antibiotics. While it may seem strange, it logically. Suppose that I, lowly bacteria to make a chemical that, say, destroys the bacterial cell wall. Do I need some protection against chemical that children are sometimes called "a drug? "

This assumption is not only logical, it may even be true, says Davis." We believe that resistance genes in actinomycetes (bacteria that produce many antibiotics) that have the same biochemical function of resistance genes "in the samples from hospital patients with genetic sequences similar -. but not identical - it suggests that genes jump between species, although Davies admits that "we can not prove it. "

Salyers, who studies the process of genes between species jumps, says that bacteria have a lot of tricks to move the resistance genes on the one hand, they seem to cause other bacteria to start the genetic swap meet. When plasmid DNA resistance released bacteria taken other bacteria, the receiver can be stimulated to release their plasmids, a process called retrotransfer ". This enables the transmission of bacteria, the ability to sample the DNA of other bacteria, "says Salyers. She said the relationship is a new form of symbiosis (

). As if this prospect bacteria merge win antibiotics not alarming enough to recognize that this generosity extends beyond the members of their own species, Salyers said. " Virtually all bacteria can get genes from any other bacteria. "

What is the evidence of this movement? Scientists are distantly related bacteria with resistance genes, DNA (

) is from 95 to 99 percent identical. Although it is highly unlikely by chance alone, a strong suggestion - but not proof -. That genes have a buy strattera common origin, but do not forget that anti-bacterial antibiotic toolkit also includes several mutations that could explain that happened in New York, where >> << deadly drug resistant was spit.