Friday, January 30, 2009

How to practically do Conjugation of Bacteria

Here practical steps are being described to perform conjugation of Bacteria.

Take two strains of bacterial cultures of e.coli. One is the male strain or the P+, which is auxotrophic for biotin and methionine (Bio-, MeC). This bacterium can grow in the minimal medium, only if these two components are supplemented. Similarly, the female bacteria or the P- strain is able to produce both biotin and methionine, but are auxotrophic for threonine and leucine (Thr-, Leu-). These bacteria cannot grow in the minimal medium unless the respective nutrients are supplemented.

But when these two populations are mixed and grown in media with only the salts and the carbon source (minimal media) some of the cells could grow without the supplementation of the additional amino acids and vitamin, biotin. This indicates that when grown together some female cells receive the functional genes of Thr and Leu from the male strains by conjugation. Similarly, some of the male strains receive the functional genes for biotin and methionine from the female strain. These new genetically transformed strains can grow in the minimal medium without any additional nutrient supplementation.

This is a common method of natural recombination in bacteria resulting in the formations of variants. In this context it is very important because conjugation can produce drug resistance among pathogenic bacteria. Therefore, the mechanism of conjugation has to be clearly understood and should be aware that in heterogonous cultures there is the chance of bacterial conjugations and genetic recombinations resulting in new strains with new weapons. Contaminated laboratory cultures, organic factory effluents, and sewage water are good media for bacterial conjugations.

Tags: Bio Technology, Bio Genetics, Bacterial Conjugation

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