Probiotic properties of Lactococcus lactis ssp. lactis HV219, isolated from human vaginal secretions.

AIMS: To determine the resistance of Lactococcus lactis ssp. lactis HV219 to acids, bile, antibiotics, inflammatory drugs and spermicides, compare adsorption of the strain to bacteria and Caco-2 cells under stress, and evaluate the antimicrobial activity of bacteriocin HV219. METHODS AND RESULTS: Bacteriocin HV219 activity against Gram-positive and Gram-negative bacteria was confirmed by leakage of DNA and beta-galactosidase, and atomic force microscopy. Adsorption of bacteriocin HV219 to bacteria is influenced by pH, temperature, surfactants and salts. Initially, only 3% of HV219 cells adhered to Caco-2 cells. However, after 2 h, adherence increased to 7%. Strain HV219 and Listeria monocytogenes ScottA did not compete for colonization. Strain HV219 is sensitive to most antibiotics tested, but resistant to amikacin, ceftazidime, nalidixic acid, metronidazole, neomycin, oxacillin, streptomycin, sulphafurazole, sulphamethoxazole, sulphonamides, tetracycline and tobramycin. Ibuprofen, ciprofloxacin, diklofenak and nonoxylol-9 inhibited the growth of strain HV219. CONCLUSION: Strain HV219 is resistant to hostile conditions in the intestinal tract, including therapeutic levels of specific antibiotics and binds to Caco-2 cells, but not in competition with L. monocytogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: Strain HV219 will only be effective as probiotic if taken with specific antibiotics and not with anti-inflammatory drugs and spermicides.

[Calcium ions and the differentiation of Streptomyces hygroscopicus 155, a producer of an antibiotic complex]. / Iony kal'tsiia i differentsiatsiia Streptomyces hygroscopicus 155, produtsenta antibioticheskogo kompleksa.

The effect of Ca2+ on differentiation of Streptomyces hygroscopicus 155 and its inactive variant 155-0 was studied. Addition of Ca2+ to the medium induced formation of the aerial mycelium in the inactive variant and accelerated formation of the aerial mycelium in the parent strain. The inhibitory effect of EGTA, verapamil, nifedipin, chlorpromazine and dilthiazeme on the aerial mycelium formation demonstrated the physiological role of Ca2+ in the process. Addition of pandavir (nigericin) and azalomycin B, the antibiotics produced by the streptomycete, induced formation of the aerial mycelium in the inactive variant. The effect was higher in the presence of Ca2+. Streptomyces hygroscopicus 155 and its inactive variant synthesized a proteolytic complex containing metalloproteases and trypsin-like proteases. The total proteolytic activity of the inactive variant was lower than that of the parent strain. Addition of Ca2+ to the medium stimulated their proteolytic activity. The inducing action of the antibiotics produced by the parent strain on differentiation of S.hygroscopicus 155-0 and the increase of their action in the presence of Ca2+ suggested that they controlled the differentiation and that such a function of the antibiotics expressed itself through the Ca2+ signal system.

[Calcium ions in the life cycle of Streptomyces albogriseolus 444]. / Iony kal'tsiia v zhiznennom tsikle Streptomyces albogriseolus 444.

The influence of Ca2+ on the growth, antibiotic production and differentiation of Streptomyces albogriseolus 444 was studied. Consumption of the calcium ions by the strain was followed up. It was shown that Ca2+ changed the dynamics of the biomass accumulation and had no significant effect on the antibiotic production. Calcium present in the medium was assimilated more intensively during the first 24 hours of the strain growth. The own antibiotic nigericin exogenously added to the medium increased the calcium assimilation. In the presence of Ca2+ the nigericin stimulation of the strain differentiation was higher.

[Physiological role of extracellular proteases and calcium ions in the processes of differentiation and antibiotic production by Streptomyces albogriseolus 444]. / Fiziologicheskaia rol' vnekletochnykh proteaz i ionov kal'tsiia v protsessakh differentsiatsii i antibiotikoobrazovaniia Streptomyces albogriseolus 444.

The extracellular proteolytic activity of Streptomyces albogriseolus 444 was investigated. S. albogriseolus 444 was shown to synthesize an extracellular proteolytic complex with metal-protease and trypsin-like activity defining differentiation of the substrate mycelium to the aerial one as well as the spore formation. The synthesis of the complex proceeded in the absence of the inductor in the medium i.e. constitutively. The complex heterogeneity was confirmed chromatographically. Low concentration of calcium ions (1.5 mM) stimulated the total caseinolytic activity and suppressed the activity of the trypsin-like proteases.

[Isolation and partial characterization of NAD+ kinase from Streptomyces albogriseolus 444]. / Vydelenie i chastichnaya kharakteristika NAD+ kinazy Streptomyces albogriseolus 444

NAD+ kinase was isolated from the culture of Streptomyces albogriseolus 444. an organism producing an antibiotic complex. The enzyme was partially characterized. Its molecular weight is 141219 Da.

[Effect of calcium ions on the differentiation of actinomycetes]. / Vliianie ionov kal'tsiia na differentsiatsiiu aktinomitsetov.

The influence of Ca2+ on the formation of the aerial mycelium in 23 actinomycete strains was studied. It was shown that in concentrations up to 5 mM exogenous Ca2+ induced the formation of the aerial mycelium in 11 out of the 23 actinomycete strains tested. The Ca2+ channel blockers (verapamil and nifedipine), calmodulin inhibitor (chlorpromazine) and Ca2+ chelator (EGTA) inhibited the aerial mycelium formation in 3 streptomycete strains out of the 23 actinomycetes. Chlorpromazine and nifedipine proved to be the most active inhibitors when used in concentrations of 0.2 to 2.5 mumol/disk. The Ca2+ concentrations of 5 mM were found to stimulate the formation of the submerged spores in S. hygroscopicus 155. The activity of ATP synthase was stimulated in the aerial and submerged spores after the Ca2+ uptake.