Article
Isolation of tellurite- and selenite-resistant bacteria from hydrothermal vents of the Juan de Fuca Ridge in the Pacific Ocean.
Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada.
Applied and Environmental Microbiology (impact factor:
3.83).
10/2002;
68(9):4613-22.
pp.4613-22
Source: PubMed
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Citations (0)
- Cited In (7)
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Article: Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors.
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ABSTRACT: Certain toxic elements support the metabolism of diverse prokaryotes by serving as respiratory electron acceptors for growth. Here, we demonstrate that two anaerobes previously shown to be capable of respiring oxyanions of selenium also achieve growth by reduction of either tellurate [Te(VI)] or tellurite [Te(IV)] to elemental tellurium [Te(0)]. This reduction achieves a sizeable stable-Te-isotopic fractionation (isotopic enrichment factor [epsilon] = -0.4 to -1.0 per ml per atomic mass unit) and results in the formation of unique crystalline Te(0) nanoarchitectures as end products. The Te(0) crystals occur internally within but mainly externally from the cells, and each microorganism forms a distinctly different structure. Those formed by Bacillus selenitireducens initially are nanorods ( approximately 10-nm diameter by 200-nm length), which cluster together, forming larger ( approximately 1,000-nm) rosettes composed of numerous individual shards ( approximately 100-nm width by 1,000-nm length). In contrast, Sulfurospirillum barnesii forms extremely small, irregularly shaped nanospheres (diameter < 50 nm) that coalesce into larger composite aggregates. Energy-dispersive X-ray spectroscopy and selected area electron diffraction indicate that both biominerals are composed entirely of Te and are crystalline, while Raman spectroscopy confirms that they are in the elemental state. These Te biominerals have specific spectral signatures (UV-visible light, Raman) that also provide clues to their internal structures. The use of microorganisms to generate Te nanomaterials may be an alternative for bench-scale syntheses. Additionally, they may also generate products with unique properties unattainable by conventional physical/chemical methods.Applied and Environmental Microbiology 04/2007; 73(7):2135-43. · 3.83 Impact Factor -
Article: Effects of Selenite and Tellurite on Growth, Physiology, and Proteome of a Moderately Halophilic Bacterium
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ABSTRACT: We isolated a moderately halophilic bacterium with high level of tolerance to two toxic oxyanions, selenite and tellurite, from hypersaline soil in Garmsar, Iran. 16s rRNA sequence analysis revealed that the isolate, strain MAM, had 98% similarity with Halomonas elongate, and is closely related to other species of the genus Halomonas. We observed that the tolerance to tellurite and its removal increased significantly when both selenite and tellurite were added to the culture media, suggesting a positive synergism of selenite on tellurite tolerance and removal. We applied a proteomic approach to study the proteome response of Halomonas sp. strain MAM to selenite, tellurite, and selenite + tellurite. Out of 800 protein spots detected on 2-DE gels, 208 spots were differentially expressed in response to at least one of treatments. Of them, 70 CBB stained spots were analyzed by MALDI TOF/TOF mass spectrometry, leading to identification of 36 proteins. Our results revealed that several mechanisms including fatty acid synthesis, energy production, cell transport, oxidative stress detoxification, DNA replication, transcription and translation contributed in bacterial response and/or adaptation. These results provided new insights into the general mechanisms on the tolerance of halophilic bacteria to these two toxic oxyanions and the use of them for bioremediation of contaminated saline soils and wastes discharge sites.Keywords: halophilic bacteria; Halomonas; selenite; tellurite; proteomics; heavy metals tolerance; Acetyl-CoA carboxylase; BirAJournal of Proteome Research 06/2009; 8(6). · 5.11 Impact Factor -
Article: Aeration controls the reduction and methylation of tellurium by the aerobic, tellurite-resistant marine yeast Rhodotorula mucilaginosa.
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ABSTRACT: We previously described a marine, tellurite-resistant strain of the yeast Rhodotorula mucilaginosa that both precipitates intracellular Te0 and volatilizes methylated Te compounds when grown in the presence of the oxyanion tellurite. The uses of microbes as a "green" route for the production of Te0-containing nanostructures and for the remediation of Te-oxyanion wastes have great potential, and so a more thorough understanding of this process is required. Here, Te precipitation and volatilization catalyzed by R. mucilaginosa were examined in continuously aerated and sealed (low oxygen concentration) batch cultures. Continuous aeration was found to strongly promote Te volatilization while inhibiting Te0 precipitation. This differs from the results in sealed batch cultures, for which tellurite reduction to Te0 was found to be very efficient. We show also that volatile Te species may be degraded rapidly in medium and converted to the particulate form by biological activity. Further experiments revealed that Te0 precipitates produced by R. mucilaginosa can be further transformed to volatile and dissolved Te species. However, it was not clearly determined whether Te0 is a required intermediate for Te volatilization. Based on these results, we conclude that low oxygen concentrations will be the most efficient for production of Te0 nanoparticles while limiting the production of toxic volatile Te species, although the production of these compounds may never be completely eliminated.Applied and environmental microbiology 07/2011; 77(13):4610-7. · 3.69 Impact Factor
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Keywords
10 strains
bacterial films
Deep-ocean hydrothermal-vent environments
genus Pseudoalteromonas
greater
heavy metals
metalloid resistance
metalloid-oxide-reducing bacteria
metalloid-oxide-resistant
metalloids
ocean water
pH tolerant
Phylogenetic analysis
phylogenetic characteristics
present excellent sites
salt tolerant
selenite-reducing strains
selenium
Tellurite-
thermotolerant
