ABSTRACT
The effects of cadmium and diuron, typical environmental pollutants, on the survival of predatory bacteria of the genus Bdellovibrio were studied. The adhesion and cohesion of bdellovibrios were shown to enhance cell resistance to xenobiotics. The viability of Bdellovibrio cells was shown to be higher at the stage of bdelloplasts. The obtained results confirm the concept of the surface-associated existence of Bdellovibrio in the natural environment and serve as a basis for the employment of predatory bacteria to solve the problems of human population health, biological protection of ecosystems, and bioterrorism protection.
Subject(s)
Bdellovibrio/physiology , Bacterial Adhesion/physiology , Bdellovibrio/drug effects , Cadmium/pharmacology , Diuron/pharmacology , Environmental Pollutants/pharmacologyABSTRACT
The paper deals with a comparative study of the growth of free-living and immobilized predatory bacteria of the genus Bdellovibrio in the presence of toxic concentrations of urea and phenol. It was found that the cell wall of bdelloplasts plays a protective role in the adaptation of bdellovibrios to xenobiotics. The attachment of bdellovibrios to solid surfaces allows them to survive under unfavorable environmental conditions.
Subject(s)
Bdellovibrio/physiology , Environmental Pollutants , Phenol , Urea , Adaptation, Physiological , Bacterial Adhesion , Bdellovibrio/drug effects , Bdellovibrio/growth & development , Cell Wall/drug effects , Culture Media , Environmental Pollutants/pharmacologyABSTRACT
The data on the interaction of bacteria of the genus Bdellovibrio with the representatives of pathogenic Salmonella typhimurium are presented. Different types of such interaction are demonstrated: in a two-component system, in fluid media, in an agar layer and on the surface of a solid carrier. As shown for the first time, Bdellovibrio cells are capable of interacting not only with actively growing bacteria, but also with their noncultivable forms. The data obtained may serve as the basis for the study of possible practical use of such bacteria for controlling Gram-negative organisms, the causative agents of sapronotic infections.
Subject(s)
Bdellovibrio/physiology , Salmonella typhimurium/physiology , Agar , Bacteriolysis , Culture Media , Periplasm/microbiology , Plastics , Salmonella typhimurium/growth & developmentABSTRACT
We studied the effect of various concentrations of ecologically hazardous pollutants, urea, phenol, diuron, and cadmium ions, on the physiological activity and survival of the parasitic bacterium Bdellovibrio. Experiments showed that the survival of bdellovibrios in the presence of the pollutants was two times higher when they were cultivated on agar than when they were cultivated in liquid medium. The data obtained are in agreement with the recent concept of the surface-associated state as a survival strategy of bdellovibrios in various ecosystems.
Subject(s)
Bdellovibrio/drug effects , Bdellovibrio/physiology , Environmental Pollutants/toxicity , Cadmium/toxicity , Diuron/toxicity , Phenols/toxicity , Urea/toxicityABSTRACT
Conditions for separation of Micavibrio aeruginosavorus ARL-1 from cells and membranes of host-bacteria Pseudomonas aeruginosa have been developed. Differential centrifugation and ficoll density-gradient centrifugation were applied to purify a mixed culture. A fraction localized in the zone of 12-15% ficoll is a sufficiently homogenous suspension of the exoparasite . It meets requirements of purity of the biomass destined for biochemical investigations.
Subject(s)
Bacteria/isolation & purification , Bacteriological Techniques , Centrifugation, Density Gradient , Pseudomonas aeruginosaABSTRACT
Acid RNAase Pch2 was isolated from a filtrate of the cultural fluid of the fungus Penicillium chrysogenum 152A and purified to homogeneity. An analysis of RNAase Pch2 action on RNA and synthetic substrates showed that the enzyme can be attributed to non-specific true ribonucleases (ribonucleate-3'-oligo-nucleotide hydrolase, EC 3.1.4.23). The maximal effect of the enzyme on RNA is observe at pH 4.5 and 55 degree. The RNAase Pch2 is not activated by bivalent metal ions, p-chloromercurybenzoate or beta-mercaptoethanol and is reversibly inactivated by 8 M urea. The enzyme molecule consists of 332 amino acid residues; its molecular weight is 36160, the isoelectric point lies at 5.2.
Subject(s)
Endonucleases/metabolism , Endoribonucleases , Penicillium chrysogenum/enzymology , Penicillium/enzymology , Ribonucleases/metabolism , Amino Acids/analysis , Endonucleases/isolation & purification , Kinetics , Molecular Weight , Ribonucleases/isolation & purification , Substrate Specificity , Urea/pharmacologyABSTRACT
The effect of photo-oxidation and carboxymethylation on the activity of RNAse Pch1 has been studied. Photoinactivation in the presence of rose bengal results in a selective oxidation of two histidine residues. The process is inhibited by the nucleotide substrate analogs. This suggests that one or two imidazole groups may be localized in the active site of RNAse Pch1. The pH dependence of the enzyme inactivation by bromoacetic acid is indicative of the contribution of a functional group with pKa 4,0, presumably of a beta- or gamma-carboxyl group of dicarbonic amino acid. The reaction is inhibited by the substrate analogs 2'(3')-GMP and 2'(3')-AMP. The data on the similarity of active sites in several guanyloribonucleases are discussed.
