Antibiotiki i meditsinskaia biotekhnologiia = Antibiotics and medical biotechnology最新文献

Chromatographic properties of meningococcal polysaccharides and vaccines of serogroups A and C prepared at the G. N. Gabrichevskiĭ Moscow Research Institute of Epidemiology and Microbiology were studied during determination of their molecular parameters by gel filtration on sepharose 4B. It was shown that the character of the polysaccharide elution was not affected by the composition of the eluent and pH changes within the ranges of 6.5-8.5. The ionic strength of the solvent should be at least 0.2 mol/l. Immunochemical methods such as countercurrent and rocket immunoelectrophoresis were standardized and recommended for quantitative evaluation of the content of meningococcal polysaccharides of groups A and C in the eluates. Rocket immunoelectrophoresis was shown to be more accurate and reproducible.

A photometric (turbidimetric) method was proposed for automatic control of the content of potassium benzylpenicillin crystals after centrifugation. The optical properties of the technological media were studied. It was found that along with intensive absorption in the UV spectrum due to the presence of the penicillin and its degradation products the solutions absorbed the light of the visible spectrum (400-700 nm). Therefore, determination of the penicillin crystal concentration by light dispersion in the UV and visible spectra was possible only with a differential procedure. For the near IR region there were defined areas at 930-950, 1020-1080 and 1200-1260 nm without self-absorption of the solutions providing the use of the one-canal measurement scheme. Procedures for determining the presence of penicillin crystals by light dispersion were developed: differential procedures in the visible spectrum (490 nm) and the near IR region (940-980 nm). The use of market photometers for realization of the procedures was recommended.

A procedure for indicating strict anaerobes in microbial associations was developed. The indication is performed with two disks: aminoglycoside (amikacin, 10-micrograms disk) (A) and metronidazole aminoglycoside (metronidazole + amikacin, 5- and 10-micrograms disks respectively) (MA). Colonies growing in zone A and absent in zone MA are considered to be strictly anaerobic. The procedure is characterized by high reliability: false positive results are practically not recorded and the frequency of false negative results does not exceed 5-10 per cent. The rate of detecting anaerobes in clinical materials is significantly increased (by 1-3 days) as compared to that with the use of the routine bacterial methods. The indication procedure markedly simplifies laboratory diagnosis of anaerobic infections at the account of clear differentiation of microorganisms grown on the primary plate and possible directed selection of anaerobic colonies for further investigation which excludes the necessity of rejecting or studying other colony types. This leads to economy of nutrient media and increasing labor productivity.

The effect of bacterial polysaccharide prodigiozan on recovery after single acute blood loss (2.5 per cent of the body weight) was studied on female mice CBA x C57Bl (F1). When administered intravenously in a dose of 0.5 mg/kg to healthy animals without blood loss prodigiozan had no significant effect on erythropoiesis. Prophylactic administration of the drug 24 hours before blood loss promoted more rapid and intensive mobilization of erythropoiesis: increasing of the levels of 59Fe incorporation into the bone marrow erythroid cells and the number of erythroid cells in the spleen as compared to those in nonstimulated animals. This is probably connected with prodigiozan-mediated stimulation of stem hemopoietic cell proliferation.

Physiological aspects of Streptococcus lactis, strain MSU development in mixed culture with Rhodotorula colostri were studied in connection with nisin biosynthesis. By the IR spectra the average content of the main components in the monoculture cells of S. lactis and its association with the yeast in the stationary growth phase was the following by dry weight: 54-58 per cent of protein, 14-16 per cent of nucleic acids, 26-28 per cent of carbohydrates and 3-5 per cent of lipids. Glucose and nitrogen in the fermentation broth were consumed completely. A significant quantity of KH2PO4 remained in the fermentation broth. Lactic acid excretion was observed. S. lactis, strain MSU was the leading component of the association under the studied cultivation conditions because just its IR spectra dominated in the spectra of the mixed culture.

It was shown on a model of 2 collection strains of lactobacilli that their cultivation on a synthetic multicomponent medium with addition of threonine and subsequent exposure of the cells to lysozyme at 0 degrees C and to alkaline solution of sodium dodecylsulfate at 60 degrees C provided highly efficient detection of plasmid DNA in these organisms. Circular molecules of the plasmid DNA of the 7-kv length, their dimer forms and linear molecules were detected in both of the strains.

Specific antibodies for immunoenzymatic assay of P. aeruginosa exotoxin A were isolated with affinity chromatography on exotoxin A-Sepharose 4B. A conjugate of the antibodies to exotoxin A with beta-lactamase from Bacillus licheniformis 749/c was prepared by linking glutaric aldehydes. The conjugate showed high immunospecific and enzymatic activity and was used for competitive solid phase immunoenzymatic assay. Sensitivity of the assay provided determination of exotoxin A in concentration of 20 ng/ml. It was used for determining P. aeruginosa exotoxin A in culture fluids.