Copper resistance in Desulfovibrio strain R2.
ABSTRACT A sulfate-reducing bacterium, designated as strain R2, was isolated from wastewater of a ball-bearing manufacturing facility in Tomsk, Western Siberia. This isolate was resistant up to 800 mg Cu/l in the growth medium. By comparison, Cu-resistance of reference cultures of sulfate-reducing bacteria ranged from 50 to 75 mg Cu/l. Growth experiments with strain R2 showed that Cu was an essential trace element and, on one hand, enhanced growth at concentrations up to 10 mg/l but, on the other hand, the growth rate decreased and lag-period extended at copper concentrations of >50 mg/l. Phenotypic characteristics and a 1078 bp nucleotide sequence of the 16S rDNA placed strain R2 within the genus Desulfovibrio. Desulfovibrio R2 carried at least one plasmid of approximately of 23.1 kbp. A 636 bp fragment of the pcoR gene of the pco operon that encodes Cu resistance was amplified by PCR from plasmid DNA of strain R2. The pco genes are involved in Cu-resistance in some enteric and aerobic soil bacteria. Desulfovibrio R2 is a prospective strain for bioremediation purposes and for developing a homologous system for transformation of Cu-resistance in sulfate-reducing bacteria.
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ABSTRACT: A cosmid library of copper-resistant (Cur) Pseudomonas syringae pv. tomato PT23 plasmid DNA was constructed and mobilized into the copper-sensitive recipient P. syringae pv. syringae PS61. One resultant cosmid clone, pCOP1 (46 kilobases), conferred copper resistance. The PT23 Cur gene(s) was located on pCOP1 by subcloning PstI restriction endonuclease fragments of pCOP1 in the broad-host-range vector pRK404. A subclone containing a 4.4-kilobase PstI fragment conferred Cur on PS61. The Cur gene(s) was further located by insertional inactivation with Tn5. A subcloned fragment internal to the Cur determinant on pCOP2 was probed to plasmid and chromosomal DNA of four copper-resistant and three copper-sensitive strains of P. syringae pv. tomato. The probe hybridized to plasmids in resistant strains, but showed no detectable homology to copper-sensitive strains.Journal of Bacteriology 03/1987; 169(2):470-4. · 3.19 Impact Factor
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ABSTRACT: Organic waste materials were tested as the electron donors for sulphate reducers in treating acid mind drainage. They are oak chips (OC), spent oak from shiitake farms (SOS), spent mushroom compost (SMC), sludge from a wastepaper recycling plant (SWP) and organic-rich soil (ORS). The materials were placed in column reactors, which were inoculated by anaerobic digester fluid. The number of sulphate-reducers increased to 108–109 cells/ml in 2 weeks in the reactors. The reactors were continuously fed with simulated mine drainage for 35 weeks to determine sulphate reduction and metal removal. SOS, SMC and SWP served better as electron donors than OC and ORS. Metal removal efficiency of the reactor with OC was lower than those with SOS, SMC and SWP at the beginning, but became comparable at a later stage. The solvent extractable of OC inhibited the growth of sulphate-reducers. Cellulose polysaccharides were the main components of the waste materials consumed in the reactors.Water Research. 01/2000;
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ABSTRACT: The sequence databases continue to grow at an extraordinary rate. Contributions come from both small laboratories and large-scale projects, such as the Merck EST project. This growth has placed new demands on computational sequence comparison tools such as BLAST. Even now it is no longer practical to evaluate some BLAST reports manually; it is necessary to filter the output by, for example, organism, source, or degree of annotation. The new network BLAST service makes such tools possible. It is also possible to present BLAST output in different formats, such as BLANCE. Perhaps most important of all, it becomes simple to call BLAST from another application, making it one step within an integrated system. This makes the automated preparation of sequence evaluations that include BLAST runs possible. In the near future we expect to see a number of applications that use the network BLAST interface to help molecular biologists search against a database that is growing not only in size but in biological richness.Methods in Enzymology 02/1996; 266:131-41. · 2.00 Impact Factor