11 July 2008

Biotechnology for medicine

The use of biotechnology of the potential of living organisms in the vital interests of man, his research and economic activities allows solving various problems. They are related to medical support and include the diagnosis and treatment of particularly dangerous diseases;  with the task of replenishing food reserves due to lack of food; with human nature conservation activities and are aimed at creating new energy carriers due to depletion of natural reserves and at preventing environmental pollution;  with the task of maintaining ecological balance and concern the conservation of biological diversity, the creation of specialized living systems and the study of the laws of ecosystem processes during their introduction. There are many problems and tasks, and their solution is based on fundamental research. But I would like to note that biotechnology solves not only specific tasks of science, production, agriculture and medicine. It has a more global methodological task — it expands and accelerates the scale of human impacts on wildlife and contributes to the adaptation of living systems to human conditions, i.e. to the noosphere. Biotechnology, therefore, acts as a powerful factor of anthropogenic adaptive evolution. Any biotechnological product, whether it is a medical preparation, or a food product, or a means of combating agricultural pests, can contribute to the adaptation of a person to the conditions of his existence or cause such changes in the habitat that can disrupt the adaptive capabilities of a person. In any case, the use of living systems to preserve the quality and improve the human environment is directly related to the problem of longevity.

First of all, let's turn to the medical branch of biotechnology. Considering the various classes of compounds used in clinical practice and obtained by biotechnology methods, first of all, it is necessary to name antibiotics - the largest class of pharmaceutical compounds, the synthesis of which is carried out by microbial cells. Antifungal agents, anticancer drugs and alkaloids belong to the same class. The production of antibiotics amounts to thousands of tons. Penicillins are known to have been isolated in the cultivation of fungi of the genus Penicillium. In 1945, the mold Cephalosporium acremonium was isolated from a sample of seawater, synthesizing several antibiotics; one of them, cephalosporin C, was particularly effective against gram-positive bacteria resistant to penicillin.

Of the several thousand antibiotics discovered, the lion's share belongs to actinomycetes. Among actinomycetes, the genus Streptomyces makes the greatest contribution, the species Streptomyces griseus alone synthesizes more than fifty antibiotics. Since the mid-1960s, due to the increased complexity of isolating effective antibiotics and the spread of resistance to the most widely used compounds in a large number of pathogenic bacteria, researchers have moved from searching for new antibiotics to modifying the structure of existing ones. They sought to increase the effectiveness of antibiotics, to find protection against inactivation by enzymes of resistant bacteria and to improve the pharmacological properties of drugs. Merck, Sharp and Dome researchers have discovered a new class of b-lactam antibiotics, thienamycins produced by Streptomyces cattleya. Thienamycins are extremely effective against gram-positive and gram-negative bacteria, and are also able to inhibit b-lactamases, which significantly increases the capabilities of these drugs.

Antibiotics are produced as a result of the combined action of the products of 10-30 genes, so it is almost impossible to detect individual spontaneous mutations that could increase the yield of an antibiotic from a few milligrams per liter in a wild-type strain to 20 g/l or more. Such highly productive strains of Penicillium chrysogenum or Streptomyces auerofaclens (producers of penicillin or tetracycline) were obtained as a result of successive cycles of mutagenesis and selection. Certain mutants, the so-called idiots, are able to synthesize only half of the antibiotic molecule, and the medium must be enriched with its other half. This form of mutational biosynthesis has led to the discovery of new derivatives of antibiotics.

The number of antitumor substances of microbial origin is quite limited. Bleomycin, isolated from Streptomyces verticilliis cultures, is a glycopeptide that acts by tearing the DNA of tumor cells and disrupting DNA and RNA replication. Another group of antitumor agents is based on a combination of an aminoglycoside unit and an anthracycline molecule. The disadvantage of both compounds is their potential danger to the heart.

Antibiotics are used by fungi and actinomycetes in competition in their natural habitat. A person has used these compounds for the treatment of infectious and oncological diseases. This was a kind of impetus for evolutionary transformations in the microbial environment, resistant strains of bacteria began to arise. In this regard, the problem of creating a new generation of more effective antibiotics has arisen again. Currently, the protocol for the treatment of infectious and surgical pathology necessarily includes antibiotics. But, having undeniable advantages, antibiotics also have a negative effect on the human body: the microflora of the gastrointestinal tract is disturbed, complications in the functioning of the kidneys and liver are possible, the immune system is suppressed. Therefore, modern treatment regimens are complex and aimed at maintaining the adaptive capabilities of a person.

Found a typo? Select it and press ctrl + enter Print version