Exposure to sulfide causes population shifts in sulfate-reducing consortia

The shift in the community structure of a mixed culture of sulfate-reducing bacteria (SRB) at 0.5, 0.75, 1, and 1.5 kg m−3 sulfide loadings was investigated in an anaerobic continuous bioreactor used for treatment of sulfate-containing wastewater by fluorescence in situ hybridization (FISH), using SRB species-specific and group-specific 16S rRNA-targeting probes. Hybridization analysis using these 16S rRNA-targeted oligonucleotide probes revealed that sulfide was toxic for Desulfonema, Desulfobulbus spp. and the Desulfobacteriaceae group, although it was not toxic for Desulfobacter, Desulfotomaculum, Desulfobacterium spp. or the Desulfovibrionaceae group. On the other hand, only a high concentration of sulfide of 1.5 kg m−3 was found to be toxic for the Desulfococcus group in the bioreactor. When the sulfide in the feed was 1.00 kg m−3 the sulfate-reducing capacity of the system decreased, and this decrease was more pronounced when the inlet sulfide was further increased to 1.5 kg m−

Identification of population dynamics in sulfate-reducing consortia on exposure to sulphate

The microbial population structure and function of a mixed culture of sulfate-reducing bacteria (SRB) maintained in anaerobic continuous bioreactors were tracked before and after a major perturbation, which involved the addition of sulfate to the influent of a bioreactor when operated at steady state at 35 °C, pH 7.8 and a 2.5 day residence time with feed stream containing 10 and 15 kg m−3 sulfate as terminal electron acceptor and 19.6 and 29.4 kg m−3 ethanol as carbon source and electron donor, respectively. The population structure determined by fluorescence in situ hybridization (FISH), by using 16S rRNA-targeted oligonucleotide probes, was linked to the functional performance of the SRB in the reactor. Hybridization analysis using these 16S rRNA-targeted oligonucleotide probes revealed that a high concentration of sulfate was toxic for Desulfobacterium and Desulfobulbus. On the other hand, the Desulfococcus group was found to be the most dominant group of SRB in the feed stream containing 15 kg m−3 sulfate as terminal electron acceptor and 29.4 kg m−3 ethanol as carbon source and electron donor

A study of the relative dominance of selected anaerobic sulphate-reducing bacteria in a continuous bioreactor revealed by fluorescence in situ hybridisation

The diversity and the community structure of sulfate-reducing bacteria (SRB) in an anaerobic continuous bioreactor used for treatment of a sulfate-containing wastewater were investigated by fluorescence in situ hybridization. Hybridization to the 16S rRNA probe EUB338 for the domain Bacteria was performed, followed by a nonsense probe NON338 as a control for nonspecific staining. Sulfate-reducing consortia were identified by using five nominally genus-specific probes (SRB129 for Desulfobacter, SRB221 for Desulfobacterium, SRB228 for Desulfotomaculum, SRB660 for Desulfobulbus, and SRB657 for Desulfonema) and four group-specific probes (SRB385 as a general SRB probe, SRB687 for Desulfovibrioaceae, SRB814 for Desulfococcus group, and SRB804 for Desulfobacteriaceae). The total prokaryotic population was determined by 4′,6-diamidino-2-phenylindole staining. Hybridization analysis using these 16S rRNA-targeted oligonucleotide probes showed that, of those microbial groupings investigated, Desulfonema, Desulfobulbus, spp., and Desulfobacteriaceae group were the main sulfate-reducing bacteria in the bioreactor when operated at steady state at 35°C, pH 7.8, and a 2.5-day residence time with feed stream containing 2.5 kg m−3 sulfate as terminal electron acceptor and 2.3 kg m−3 acetate as carbon source and electron donor

Potential impact of forest management and tree improvement on genetic diversity of Turkish red pine (Pinus brutia Ten.) plantations in Turkey

Genetic diversity was determined and compared by using 86 random amplified polymorphic DNA loci in 450 families originated from 18 Pinus brutia Ten. (Turkish red pine) seed sources. These seed sources were sampled at three different categories and included six seed stands from six different breeding zones and six seed orchards, and six plantations which were originated from the respective seed stands. Genetic diversity parameters among the plantations, seed orchards and seed stands were compared. There was no significant difference in genetic diversity parameters of seed sources, but the percentages of polymorphic loci were slightly higher in seed orchards than their natural counterparts. These results suggest that through phenotypic selection practiced genetic diversity residing in natural stands seems to be successfully captured in seed orchards. Mean F-ST values (F-ST = 0.10-0.11) did not vary among three different categories of seed sources. Seed orchards (F-IS = 0.03) and plantations (F-IS = 0.07) showed reduced locality inbreeding coefficients compared with seed stands (F-IS = 0.13). The dendrogram of seed stands based on genetic distances did not produce any clusters of populations that could be attributed to their geographic proximity. A representative portion of genetic diversity existing in natural populations of Turkish red pine appears to be captured in established seed orchards and plantations with seeds from seed stands

The cytotoxic effect of endemic Centaurea fenzlii Reichardt on colon cancer cell lines

International Congress on Natural Products Research on Global Change, Natural Products and Human Health/8th Joint Meeting of AFERP, ASP, GA, PSE and SIF -- JUL 28-AUG 01, 2012 -- New York, NYYIRTICI, Umit/0000-0002-0142-6105; Icgen, Bulent/0000-0001-8114-4230;WOS: 000307042801063…Amer Soc Pharmacognosy (ASP), Soc Med Plant & Nat Prod Res (GA), Italian Soc Phytochem (SIF), Phytochem Soc Europe (PSE), French Speaking Soc Pharmacognosy (AFERP

The cytotoxic effect of endemic Centaurea fenzlii Reichardt on colon cancer cell lines

International Congress on Natural Products Research on Global Change, Natural Products and Human Health/8th Joint Meeting of AFERP, ASP, GA, PSE and SIF -- JUL 28-AUG 01, 2012 -- New York, NYWOS: 000307042801063…Amer Soc Pharmacognosy (ASP), Soc Med Plant & Nat Prod Res (GA), Italian Soc Phytochem (SIF), Phytochem Soc Europe (PSE), French Speaking Soc Pharmacognosy (AFERP

Characterization of SDS-degrading Delftia acidovorans and in situ monitoring of its temporal succession in SDS-contaminated surface waters

Incomplete removal of sodium dodecyl sulfate (SDS) in wastewater treatment plants may result in SDS residues escaping and finding their way into receiving water bodies like rivers, lakes, and sea. Introduction of effective microorganisms into the aerobic treatment facilities can reduce unpleasant by-products and SDS residues. Selecting effective microorganisms for SDS treatment is a big challenge. Current study reports the isolation, identification, and in situ monitoring of an effective SDS-degrading isolate from detergent-polluted river waters. Screening was carried out by the conventional enrichment culture technique and the isolate was tentatively identified by using fatty acid methyl ester and 16S ribosomal RNA (rRNA) sequence analyses. Fatty acids produced by the isolate investigated were assumed as typical for the genus Comamonas. 16S rRNA sequence analysis also confirmed that the isolate had 95 % homology with Delftia acidovorans known as Comamonas or Pseudomonas acidovorans previously. D. acidovorans exhibited optimum growth at SDS concentration of 1 g l(-1) but tolerated up to 10 g l(-1) SDS. 87 % of 1.0 g l(-1) pure SDS was degraded after 11 days of incubation. The temporal succession of D. acidovorans in detergent-polluted river water was also monitored in situ by using Comamonas-specific fluorescein-labeled Cte probe. Being able to degrade SDS and populate in SDS-polluted surface waters, D. acidovorans isolates seem to be very helpful in elimination of SDS

Use of cadA-Specific Primers and DNA Probes as Tools to Select Cadmium Biosorbents with Potential in Remediation Strategies

Biosorption, using cadmium-resistant bacterial isolates, is often regarded as a relatively inexpensive and efficient way of cleaning up wastes, sediments, or soils polluted with cadmium. Therefore, many efforts have been devoted to the isolation of cadmium-resistant isolates for the efficient management of cadmium remediation processes. However, isolation, identification and in situ screening of efficient cadmium-resistant isolates are primary challenges. To overcome these challanges, in this study, cadA, cadmium resistance coding gene, specific primers and DNA probes were used to identify and screen cadmium-resistant bacteria in the cadmium-polluted river waters through polymerase chain reaction (PCR) and fluorescein in situ hybridization (FISH). PCR amplification of the cadA amplicon coupled with 16S rRNA sequencing revealed various gram-positive and -negative bacterial isolates harboring cadA. Accordingly, a cadA-mediated DNA probe was prepared and used for in situ screening of cadmium-resistant isolates from water samples collected from cadmium-polluted river waters. The FISH analyses of cadA probe showed highly specific and efficient hybridization with cadA harboring isolates. The use of primers and DNA probes specific for cadA gene seems to be very helpful tools for the selection and screening of cadmium biosorbents with potential to be used in the remediation of cadmium-polluted sites