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Chen Z, Gao SH, Jin M, Sun S, Lu J, Yang P, Bond PL, Yuan Z, Guo J. Physiological and transcriptomic analyses reveal CuO nanoparticle inhibition of anabolic and catabolic activities of sulfate-reducing bacterium. ENVIRONMENT INTERNATIONAL 2019; 125:65-74. [PMID: 30710801 DOI: 10.1016/j.envint.2019.01.058] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 01/21/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
The widespread use of CuO nanoparticles (NPs) results in their continuous release into the environment, which could pose risks to public health and to microbial ecosystems. Following consumption, NPs will initially enter into sewer systems and interact with and potentially influence sewer microbial communities. An understanding of the response of microbes in sewers, particularly sulfate-reducing bacteria (SRB), to the CuO NPs induced stress is important as hydrogen sulfide produced by SRB can cause sewer corrosion and odour emissions. In this study, we elucidated how the anabolic and catabolic processes of a model SRB, Desulfovibrio vulgaris Hidenborough (D. vulgaris), respond to CuO NPs. Physiological analyses indicated that the exposure of the culture to CuO NPs at elevated concentrations (>50 mg/L) inhibited both its anabolic and catabolic activities, as revealed by lowered cell proliferation and sulfate reduction rate. The antibacterial effects of CuO NPs were mainly attributed to the overproduction of reactive oxygen species. Transcriptomic analysis indicated that genes encoding for flagellar assembly and some genes involved in electron transfer and respiration were down-regulated, while genes for the ferric uptake regulator (Fur) were up-regulated. Moreover, the CuO NPs exposure significantly up-regulated genes involved in protein synthesis and ATP synthesis. These results suggest that CuO NPs inhibited energy conversion, cell mobility, and iron starvation to D. vulgaris. Meanwhile, D. vulgaris attempted to respond to the stress of CuO NPs by increasing protein and ATP synthesis. These findings offer new insights into the bacterial-nanoparticles interaction at the transcriptional level, and advance our understanding of impacts of CuO NPs on SRB in the environment.
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Affiliation(s)
- Zhaoyu Chen
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; Department of Environmental Science & Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Shu-Hong Gao
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Min Jin
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Shengjie Sun
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Ji Lu
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Ping Yang
- Department of Environmental Science & Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Philip L Bond
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Jianhua Guo
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
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Modulation of medium pH by Caulobacter crescentus facilitates recovery from uranium-induced growth arrest. Appl Environ Microbiol 2014; 80:5680-8. [PMID: 25002429 DOI: 10.1128/aem.01294-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The oxidized form of uranium [U(VI)] predominates in oxic environments and poses a major threat to ecosystems. Due to its ability to mineralize U(VI), the oligotroph Caulobacter crescentus is an attractive candidate for U(VI) bioremediation. However, the physiological basis for U(VI) tolerance is unclear. Here we demonstrated that U(VI) caused a temporary growth arrest in C. crescentus and three other bacterial species, although the duration of growth arrest was significantly shorter for C. crescentus. During the majority of the growth arrest period, cell morphology was unaltered and DNA replication initiation was inhibited. However, during the transition from growth arrest to exponential phase, cells with shorter stalks were observed, suggesting a decoupling between stalk development and the cell cycle. Upon recovery from growth arrest, C. crescentus proliferated with a growth rate comparable to that of a control without U(VI), although a fraction of these cells appeared filamentous with multiple replication start sites. Normal cell morphology was restored by the end of exponential phase. Cells did not accumulate U(VI) resistance mutations during the prolonged growth arrest, but rather, a reduction in U(VI) toxicity occurred concomitantly with an increase in medium pH. Together, these data suggest that C. crescentus recovers from U(VI)-induced growth arrest by reducing U(VI) toxicity through pH modulation. Our finding represents a unique U(VI) detoxification strategy and provides insight into how microbes cope with U(VI) under nongrowing conditions, a metabolic state that is prevalent in natural environments.
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Olaniran AO, Balgobind A, Pillay B. Bioavailability of heavy metals in soil: impact on microbial biodegradation of organic compounds and possible improvement strategies. Int J Mol Sci 2013; 14:10197-228. [PMID: 23676353 PMCID: PMC3676836 DOI: 10.3390/ijms140510197] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 04/10/2013] [Accepted: 04/24/2013] [Indexed: 11/18/2022] Open
Abstract
Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals.
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Affiliation(s)
- Ademola O. Olaniran
- Department of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban 4000, South Africa; E-Mails: (A.B.); (B.P.)
| | - Adhika Balgobind
- Department of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban 4000, South Africa; E-Mails: (A.B.); (B.P.)
| | - Balakrishna Pillay
- Department of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban 4000, South Africa; E-Mails: (A.B.); (B.P.)
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Oyetibo GO, Ilori MO, Obayori OS, Amund OO. Biodegradation of petroleum hydrocarbons in the presence of nickel and cobalt. J Basic Microbiol 2013; 53:917-27. [PMID: 23457074 DOI: 10.1002/jobm.201200151] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 08/25/2012] [Indexed: 01/24/2023]
Abstract
Bioremediation of environments co-contaminated with hydrocarbons and heavy metals often pose a challenge as heavy metals exert toxicity to existing communities of hydrocarbon degraders. Multi-resistant bacterial strains were studied for ability to degrade hydrocarbons in chemically defined media amended with 5.0 mM Ni(2+), and Co(2+). The bacteria, Pseudomonas aeruginosa CA207Ni, Burkholderia cepacia AL96Co, and Corynebacterium kutscheri FL108Hg, utilized crude oil and anthracene without lag phase at specific growth rate spanning 0.3848-0.8259 per day. The bacterial populations grew in hydrocarbon media amended with nickel (Ni) and cobalt (Co) at 0.8393-1.801 days generation time (period of exponential growth, t = 15 days). The bacteria degraded 96.24-98.97, and 92.94-96.24% of crude oil, and anthracene, respectively, within 30 days without any impedance due to metal toxicity (at 5.0 mM). Rather, there was reduction of Ni and Co concentrations in the axenic culture 30 days post-inoculation to 0.08-0.12 and 0.11-0.15 mM, respectively. The metabolic functions of the bacteria are active in the presence of toxic metals (Ni and Co) while utilizing petroleum hydrocarbons for increase in biomass. These findings are useful to other baseline studies on decommissioning of sites co-contaminated with hydrocarbons and toxic metals.
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Moberly JG, Miller CL, Brown SD, Biswas A, Brandt CC, Palumbo AV, Elias DA. Role of morphological growth state and gene expression in Desulfovibrio africanus strain Walvis Bay mercury methylation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:4926-4932. [PMID: 22500779 DOI: 10.1021/es3000933] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The biogeochemical transformations of mercury are a complex process, with the production of methylmercury, a potent human neurotoxin, repeatedly demonstrated in sulfate- and Fe(III)-reducing as well as methanogenic bacteria. However, little is known regarding the morphology, genes, or proteins involved in methylmercury generation. Desulfovibrio africanus strain Walvis Bay is a Hg-methylating δ-proteobacterium with a sequenced genome and has unusual pleomorphic forms. In this study, a relationship between the pleomorphism and Hg methylation was investigated. Proportional increases in the sigmoidal (regular) cell form corresponded with increased net MeHg production but decreased when the pinched cocci (persister) form became the major morphotype. D. africanus microarrays indicated that the ferrous iron transport genes (feoAB), as well as ribosomal genes and several genes whose products are predicted to have metal binding domains (CxxC), were up-regulated during exposure to Hg in the exponential phase. Whereas no specific methylation pathways were identified, the finding that Hg may interfere with iron transport and the correlation of growth-phase-dependent morphology with MeHg production are notable. The identification of these relationships between differential gene expression, morphology, and the growth-phase dependence of Hg transformations suggests that actively growing cells are primarily responsible for methylation, and so areas with ample carbon and electron-acceptor concentrations may also generate a higher proportion of methylmercury than more oligotrophic environments. The observation of increased iron transporter expression also suggests that Hg methylation may interfere with iron biogeochemical cycles.
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Affiliation(s)
- James G Moberly
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Sheng Y, Cao H, Li Y, Zhang Y. Effects of sulfide on sulfate reducing bacteria in response to Cu(II), Hg(II) and Cr(VI) toxicity. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s11434-011-4397-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Effects of bacterially produced precipitates on the metabolism of sulfate reducing bacteria during the bio-treatment process of copper-containing wastewater. Sci China Chem 2010. [DOI: 10.1007/s11426-010-4091-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Papadimitriou K, Boutou E, Zoumpopoulou G, Tarantilis PA, Polissiou M, Vorgias CE, Tsakalidou E. RNA arbitrarily primed PCR and fourier transform infrared spectroscopy reveal plasticity in the acid tolerance response of Streptococcus macedonicus. Appl Environ Microbiol 2008; 74:6068-76. [PMID: 18689510 PMCID: PMC2565966 DOI: 10.1128/aem.00315-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 08/03/2008] [Indexed: 11/20/2022] Open
Abstract
We have previously reported that an acid tolerance response (ATR) can be induced in Streptococcus macedonicus cells at mid-log phase after autoacidification, transient exposure to acidic pH, or acid habituation, as well as at stationary phase. Here, we compared the transcriptional profiles of these epigenetic phenotypes, by RNA arbitrarily primed PCR (RAP-PCR), and their whole-cell chemical compositions, by Fourier transform infrared spectroscopy (FT-IR). RAP-PCR fingerprints revealed significant differences among the phenotypes, indicating that gene expression during the ATR is influenced not only by the growth phase but also by the treatments employed to induce the response. The genes coding for the mannose-specific IID component, the 1,2-diacylglycerol 3-glucosyltransferase, the 3-oxoacyl-acyl carrier protein, the large subunit of carbamoyl-phosphate synthase, and a hypothetical protein were found to be induced at least under some of the acid-adapting conditions. Furthermore, principal component analysis of the second-derivative-transformed FT-IR spectra segregated S. macedonicus phenotypes individually in all spectral regions that are characteristic for major cellular constituents like the polysaccharides of the cell wall, fatty acids of the cell membrane, proteins, and other compounds that absorb in these regions. These findings provide evidence for major changes in cellular composition due to acid adaptation that were clearly different to some extent among the phenotypes. Overall, our data demonstrate the plasticity in the ATR of S. macedonicus, which reflects the inherent ability of the bacterium to adjust the response to the distinctiveness of the imposed stress condition, probably to maximize its adaptability.
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Affiliation(s)
- Konstantinos Papadimitriou
- Laboratory of Dairy Research, Department of Food Science and Technology, Agricultural University of Athens, Iera Odos 75, 118 55 Athens, Greece
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Hexavalent chromium reduction in Desulfovibrio vulgaris Hildenborough causes transitory inhibition of sulfate reduction and cell growth. Appl Microbiol Biotechnol 2008; 78:1007-16. [DOI: 10.1007/s00253-008-1381-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 01/07/2008] [Accepted: 01/18/2008] [Indexed: 10/22/2022]
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Chang IS, Kim BH. Effect of sulfate reduction activity on biological treatment of hexavalent chromium [Cr(VI)] contaminated electroplating wastewater under sulfate-rich condition. CHEMOSPHERE 2007; 68:218-26. [PMID: 17337035 DOI: 10.1016/j.chemosphere.2007.01.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2006] [Revised: 01/16/2007] [Accepted: 01/17/2007] [Indexed: 05/14/2023]
Abstract
Electroplating wastewater (EW) containing heavy metals was treated by a two-stage packed-bed reactor system. The EW was highly contaminated with hexavalent chromium and other heavy metals as well as sulfate because sulfuric acid had been mainly used to polish the surface of metals to be electroplated. This acidic EW was effectively neutralized in an alkaline reactor where limestone had been packed. The neutralized wastewater together with organic wastewater from a starch-processing factory (SPW) was fed to a bioreactor packed with waste biomass. The SPW was used to supplement the electron donor in the sulfidogenic bioreactor. During the whole operation, we investigated the stoichiometry of electron to see what could be a major factor to remove Cr in the wastewater. The removal rates of sulfate and Cr(VI) were dependent on the consumption rate of organic materials in the wastewater. The stoichiometric studies also showed that about 63% of electrons from oxidation of organic materials were used to reduce sulfate. When the electrons of sulfide oxidation to elemental sulfur was at least 1.3 times higher than that of Cr(VI) reduction to Cr(III), Cr(VI) was completely removed. This result suggests that Cr(VI) reduction can be expected to take place under sulfate-rich anaerobic conditions, and sulfide produced by sulfate reducing bacteria could be used to immobilize soluble chromium through Cr(VI) reduction.
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Affiliation(s)
- In Seop Chang
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea.
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Sarkar M, Das S, Bandyopadhaya A, Ray K, Chaudhuri K. Upregulation of human mitochondrial NADH dehydrogenase subunit 5 in intestinal epithelial cells is modulated byVibrio choleraepathogenesis. FEBS Lett 2005; 579:3449-60. [PMID: 15946665 DOI: 10.1016/j.febslet.2005.05.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2005] [Revised: 03/14/2005] [Accepted: 04/25/2005] [Indexed: 11/20/2022]
Abstract
Cholera still remains an important global predicament especially in India and other developing countries. Vibrio cholerae, the etiologic agent of cholera, colonizes the small intestine and produces an enterotoxin that is largely responsible for the watery diarrheal symptoms of the disease. Using RNA arbitrarily primed PCR, ND5 a mitochondria encoded subunit of complex I of the mitochondrial respiratory chain was found to be upregulated in the human intestinal epithelial cell line Int407 following exposure to V. cholerae. The upregulation of ND5 was not observed when Int407 was infected with Escherichia coli strains. Incubation with heat-killed V. cholerae or cholera toxin or culture supernatant also showed no such upregulation indicating the involvement of live bacteria in the process. Infection of the monolayer with aflagellate non-motile mutant of V. cholerae O395 showed a very significant (59-fold) downregulation of ND5. In contrast, a remarkable upregulation of ND5 expression (200-fold) was observed in a hyperadherent icmF insertion mutant with reduced motility. V. cholerae cheY4 null mutant defective in adherence and motility also resulted in significantly reduced levels of ND5 expression while mutant with the cheY4 gene duplicated showing increased adherence and motility resulted in increased expression of ND5. These results clearly indicate that both motility and adherence to intestinal epithelial cells are possible triggering factors contributing to ND5 mRNA expression by V. cholerae. Interestingly infection with insertion mutant in the gene coding for ToxR, the master regulator of virulence in V. cholerae resulted in significant downregulation of ND5 expression. However, infection with ctxA or toxT insertion mutants did not show any significant changes in ND5 expression compared to wild-type. Almost no expression of ND5 was observed in case of mutation in the gene coding for OmpU, a ToxR activated protein. Thus, infection of Int407 with virulence mutant strains of V. cholerae revealed that the ND5 expression is modulated by the virulence of V. cholerae in a ToxT independent manner. Although no difference in the mitochondrial copy number could be detected between infected and uninfected cells, the modulation of the expression of other mitochondrial genes were also observed. Incidentally, upon V. cholerae infection, complex I activity was found to increase about 3-folds after 6 h. This is the first report of alteration in mitochondrial gene expression upon infection of a non-invasive enteric bacterium like V. cholerae showing its modulation with adherence, motility and virulence of the organism.
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Affiliation(s)
- Madhubanti Sarkar
- Human Genetics & Genomics Group, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700 032, India
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Hoffman DR, Okon JL, Sandrin TR. Medium composition affects the degree and pattern of cadmium inhibition of naphthalene biodegradation. CHEMOSPHERE 2005; 59:919-927. [PMID: 15823325 DOI: 10.1016/j.chemosphere.2004.11.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 11/04/2004] [Accepted: 11/22/2004] [Indexed: 05/24/2023]
Abstract
Metals have been reported to inhibit organic pollutant biodegradation; however, widely varying degrees and patterns of inhibition have been reported. To investigate the roles of medium composition and metal bioavailability on these different degrees and patterns of inhibition, we assessed the impact of cadmium on naphthalene biodegradation by a newly isolated strain of Comamonas testosteroni in three chemically-defined minimal salts media (MSM): Tris-buffered MSM, PIPES-buffered MSM, and Bushnell-Haas medium. Cadmium (total concentrations of 100 and 500 microM) inhibited biodegradation in each medium. Degrees of inhibition were different in each medium. Cadmium was most inhibitory in PIPES-buffered MSM and least inhibitory in Bushnell-Haas. For example, in Bushnell-Haas medium, 100 microM cadmium reduced the cell yield more than 4-fold compared to controls not containing cadmium. The same concentration of cadmium completely inhibited growth in PIPES-buffered MSM. No difference in inhibition was observed in any medium when cadmium was added 24 h before inoculation rather than when added within one minute of inoculation. Two patterns of inhibition were observed. Inhibition occurred in a dose dependent pattern in Tris- and PIPES-buffered MSM and in a non-dose dependent pattern in Bushnell-Haas. Specifically, in Bushnell-Haas, 100 microM total cadmium extended the lag phase by 23+/-8.66 h, whereas 500 microM did not extend the lag phase. Soluble, ionic cadmium (Cd2+) concentrations were measured and modeled in each medium to assess cadmium bioavailability. In media containing 500 microM total cadmium, bioavailability was highest in Tris- and PIPES-buffered MSM and lowest in Bushnell-Haas. In Bushnell-Haas, cadmium bioavailability was initially higher in the 500 microM treatments (196+/-21.2 microM) than in the 100 microM treatments (78.2+/-2.04 microM); however, after 12 h, bioavailability was higher in the 100 microM treatments (56.4+/-24.8 micro) than the 500 microM treatments (13.3+/-1.2 microM). These data suggest that the type of medium determines the degrees and patterns by which metals inhibit biodegradation and emphasize the importance of coupling metal toxicity and bioavailability data.
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Affiliation(s)
- Douglas R Hoffman
- Department of Biology and Microbiology, University of Wisconsin Oshkosh, 800 Algoma Blvd, 142 Halsey Science Center, Oshkosh, WI 54901, USA
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