On the Genetics of Nutritional Deficiency Type, Carbon Source Selection and Screening

Domain of Genetics, Auxotroph type is a type of mutant of microorganisms. Due to gene mutation, it loses the ability to synthesize some essential growth factors by itself, and it is difficult to grow in the basic medium. It must rely on the addition of corresponding factors from external sources to survive and multiply.

Looking at the matter of Carbon Sources Selecting, the preference and utilization ability of microorganisms to carbon sources are related to their growth and metabolism. Different carbon sources have different structures and different enzyme systems, so the uptake and utilization efficiency of different carbon sources is different. The selection of carbon sources affects the growth rate of microorganisms, the generation of metabolites and many other aspects. For example, some bacteria uptake and utilize glucose rapidly, because glucose can easily enter the glycolytic pathway to provide energy for bacterial growth; while for the utilization of lactose, it is necessary to induce the production of specific permease and β-galactosidase.

As for the problem of screening, it is of great significance in genetic research. When exploring the nutritional deficiency types of microorganisms, screening methods are essential. Often take the photocopying plate method as an example, the bacterial liquid to be screened is first coated on the complete medium plate, and when the bacteria grow out, it is photoprinted with a flannel-free flannel to the basic medium plate and the supplementary medium plate with specific growth factors. The colonies grown on the basic medium plate cannot grow, but the colonies grown on the supplementary medium plate have a high probability of nutritional deficiency strains. This screening process requires fine operation and strict control of experimental conditions to prevent bacterial contamination, false positives or false negatives.

In genetics, the selection of nutrient-deficient strains, carbon sources and screening problems are interrelated. The demand or utilization of carbon sources by nutrient-deficient strains may be different from that of wild strains due to mutation; the selection of carbon sources affects the growth performance of microorganisms during the screening process, which in turn affects the accuracy of screening results. Therefore, researchers need to investigate these relationships in detail to clarify the mechanism of genetics, and lay the theoretical and practical foundation for the development of biotechnology, medicine, agriculture and other fields.