Effect of different salts and their concentration on polymyxin M biosynthesis by Bac. polymyxa Ross]

The effect of various concentrations of ammonium sulfate, sodium and potassium chlorides and sulfates on biosynthesis of polymyxin M by Bac. polymyxa Ross. on media containing wheet meal as the carbon source was studied. The culture growth, antibiotic accumulation and consumption of the main nutrients was studied as dependent on the level of the salts in the medium. The highest productivity was observed on media with the salt concentrations amounting to 1--2 per cent except sodium sulfate: changes in the concentration of the latter had practically no effect on the activity of the fermentation broth.     

Effect of inorganic phosphorus on the biosynthesis of polymyxin B]

A synthetic medium containing optimal levels of the sources of carbon, nitrogen and inorganic phosphorus and providing satisfactory yields of polymyxin B was developed for 2 strains of Bac. polymyxa 933 and VK-153. The consumption of phosphorus in the medium by the strains and the antibiotic biosynthesis levels depended on the form of phosphorus added to the medium. Optimal biosynthesis of polymyxin B was observed at lower concentration levels of soluble soluble phosphorus in the medium than the bacterial growth.     

Antagonistic interrelationships of Bifidobacterium bifidum i Proteus vulgaris in vitro in the digestive tract of gnotobiotic chicks]

The antagonistic relations between Bacterium bifidum, strain I/850 phi, and Proteus vulgaris, strain F-30, were studied. These organisms, when introduced together in equal doses into the digestive tract of gnotobiotic chickens in a single administration, were shown to create certain ecological correlations in various organs with the prevalence of bifidobacteria which exerted no negative influence on Proteus vulgaris. The additional daily administration of bifidobacteria for 3 days running in doses 1000 times as great as the initial dose, the content of both dibifobacteria and Proteus vulgaris in the intestine being at that time at its maximum, resulted in the suppression of the growth of Proteus vulgaris. Our findings indicate that the influence of the pH of the medium should be considered in order to obtain the evidence of significantly pronounced antagonistic relations between the two organisms in vitro.     

Effect of mutagenic metabolic activation of N-nitrosomorpholine on microorganisms]

Almost similar sensitivity is demonstrated of different methods of studying mutagenic metabolic activation of N-nitrosomorpholine (NM) in Salmonella typhimurium TA 1950 (host-mediated assay and the system of metabolic activation with rat liver homogenate). The role of correlation of certain ingredients of NM metabolic activation system with homogenates (homogenate and cofactor NADPH concentrations) is studied. The fact of influence of microsome protein activator (phenobarbital) on the NM mutagen activation effect is established.     

Effect of medicinal plants on the antilysozyme activity of microorganisms]

Medicinal plants effect on antilysozyme activity of E. coli, Klebsiella, S. aureus, Candida, Bifidobacterium, Bacteroides, Clostridium was evaluated in vitro. It was demonstrated that the effects differed substancially according to the microorganism taxonomy. The experimental data on the plants inhibitory activity may be used for elaboration of effective regimes of infections and disbiosis treatment.     

Opsonizing activity of the serum of gnotobiotic guinea pigs contaminated with individual representatives of intestinal microflora]

The influence of contamination of germfree guinea pigs with individual representatives of the intestinal microflora (Bac. mesentericus, Bac. subtilis, S. albus, and S. faecalis) on the formation of the serum opsonic activity was studied. An increase of the opsonic activity to all the microorganisms on the 11th day after a corresponding monocontamination and a stimulating influence of the serum on the intracellular digestion of Bac. mesentericus and Bac. subtilis microbes was noted. As to the pathogenic microorganisms (E. coli 055), S. Faecalis only were capable of stimulating the serum opsonic activity. The results indicated the presence of an association between the microflora composition and the opsonic activity of the animal blood serum. The value of this index also depended on the properties of the phagocytosis object.     

保和丸对食积小鼠的肠道微生物及酶活性的影响

目的 探究保和丸对食积小鼠肠道微生物及酶活性的影响。方法 将32只实验小鼠（雌雄各半）随机分为正常组（n=12）、食积组（n=10）和治疗组（n=10）。其中正常组喂食正常饲料,其余组喂食特制饲料。待食积组和治疗组中小鼠出现粪便干结,腹部膨隆胀满后,立即对治疗组按6.67 g/(kg·d)剂量灌胃0.28 g/mL的保和丸汤剂,正常组与食积组灌胃等量的蒸馏水。每天2次,每次0.35 mL,持续4 d。比较分析小鼠肠道微生物及肠道酶活性。结果 肠道微生物方面,食积组能显著增加细菌、乳酸菌、双歧杆菌和大肠埃希菌的数目,与正常组相比差异有统计学意义（均P0.05）。结论 保和丸能降低食积小鼠的细菌、乳酸菌以及大肠埃希菌的数目,同时能降低木聚糖酶、淀粉酶、蛋白酶和蔗糖酶等的活性。     

The genomics of probiotic intestinal microorganisms

An intestinal population of beneficial commensal microorganisms helps maintain human health, and some of these bacteria have been found to significantly reduce the risk of gut-associated disease and to alleviate disease symptoms. The genomic characterization of probiotic bacteria and other commensal intestinal bacteria that is now under way will help to deepen our understanding of their beneficial effects.     

Effect of alternating milieu changes on specific substrate consumption in microorganisms]

In technical microbiology microorganisms often undergo alternating milieu changes. For instance, this is the case in recirculation reactors. The organisms react on these changes with an increase of entropy production and in connection with this with increasing substrate consumption. This increasing substrate consumption contradicts the aim of an optimum yield from a given substrate. Thus, studies of the reaction of microbial growth to alternating milieu changes are of great importance. A simple model of the influence of alternating milieu changes on specific substrate consumption is given. In it the biological conversion of substances is built up by an irreversible consecutive reaction. After preliminary examinations on the analogue computer the reaction of the model to alternating perturbations is simulated on the digital computer. The results of the stimulations are compared with experimental data. The good agreement of experiment and model justifies the use of the simple formulation in the preparation of technical processes.