Microbiological Technology

the methods and apparatus used in studying microorganisms under laboratory conditions.

The specific characteristics of microorganisms, which are a function of their small size and of features of their morphology and physiology, have necessitated the development of methods of detecting, identifying, isolating, growing, counting, and describing the microbes. The foundations of microbiological technology were laid in the second half of the 19th century by L. Pasteur, R. Koch, S. N. Vinogradskii, and M. Beyerinck.

One of the fundamental methods of microbiological technology is the culturing of microorganisms in a specific medium. The apparatus and all objects that come in contact with both the culture and the medium are sterilized before inoculation. A pure culture, containing only the microbial species to be studied, is usually obtained by separating it out of isolated colonies grown on solid nutrient media. This is facilitated by transplanting the colonies and using liquid and solid differentially diagnostic (and other elective) nutrient media in which conditions are created for the predominant development of a particular species. For example, thermophiles are isolated by culturing at relatively high temperatures, autotrophes are grown on a medium containing no organic matter, and anaerobes are grown under conditions that prevent the access of atmospheric oxygen. In a number of cases, the development of extraneous microorganisms is inhibited by means of antibiotics. Laboratory animals or tissue cultures are infected in order to identify and accumulate certain pathogens.

Various types of microscopy are used to study the morphology, motility, reproduction, and structure of microorganisms. Fixed and stained preparations of microorganisms and elective methods of staining their spores or intracellular structures (for example, nuclei, cell walls, flagellae, and various inclusions, such as metachromatic granules and lipids) help in identifying the organisms and in studying their composition and structure. Various methods of immunological, physicochemical, biochemical, and genetic analysis are used to investigate the antigenic, physiological, and biochemical properties and the pathogenicity, virulence, and genetic variability of the microbes.

Faster methods have been developed for detecting microbes in the environment and the discharges of infectious patients, as well as in test materials. The serological luminescence method, which consists in treating a preparation of the material with fluorescent immunoglobulins, has become very important. The immunoglobulins are adsorbed by the corresponding microbes and cause the latter to glow when examined under a luminescence microscope.

The adoption of microbiological technology has fostered progress in a number of biological disciplines—above all, in biochemistry and genetics. The spread of the methods of tissue and cell culture has also led to the use of microbiological technology in plant and animal cytology, physiology, and immunology.

The broad scale of application of microbiologcial technology has necessitated the invention of various special equipment, from laboratory utensils to fermenting chambers that automatically monitor the culture regime.