Auxanography

Auxanography is the study of the effects of changes in environment on the growth of microorganisms, by means of auxanograms.[1] It was first devised by Beijerinck[2] for testing the effect of various nutrient media upon bacteria.[3]

The bacteria are plated out in a medium known to be poorly adapted for their nourishment, and then drops of the tested solutions are added to the surface of the plate. If the requisite nutrient has been added, the bacteria will develop rapidly in these spots.[3]

If one is interested in as many different mutants as possible, one can e.g. the growth requirement of the mutants using an auxanography test very easy to detect. It is based on sown on minimal plates auxotrophic microorganisms grow only at the site of the plate at which the needed growth substance was applied. One therefore goes in such a case So before that there is a dense suspension of the mutant on minimal agar apply and then place filter paper slices at various points, which were soaked in growth mixtures. The Growth Substance Blends are compiled so that the same growth substance only in 2 Mixtures occurs. After incubation should therefore be with monoauxotrophic Mutants show growth each by 2 filter paper slices. Occasionally di-auxotrophic mutants can also be obtained with this method identify, then, namely, if both growth substances coincidentally in the same Mixture occur. Then one finds both growth around this slice as well as between two other slices, each one of which contains growth substances required. According to the laws of combinatorics can when using in mixtures with (n-1) growth substances (n2 - n) / 2 test fabrics simultaneously. Used to detect the microbes, which are to produce growth factor such as vitamin, amino acids extra cellularly.