Browsing by Author "Ostah, N."
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Item Metadata only Antimony biomethylation by mixed-cultures of microorganisms under anaerobic conditions.(John Wiley & Sons, Ltd., 1998) Jenkins, R. O.; Craig, P. J.; Miller, D. P.; Stoop, L. C. A. M.; Ostah, N.; Morris, T-AThe volatile antimony compound trimethylantimony (TMA) was detected in headspace gases over anaerobic soil enrichment cultures spiked with potassium antimony tartrate. The presence of TMA was variable (12 positives from 104 cultures) and dependent upon both the inoculum source (environmental sample) and enrichment culture conditions. Positives for TMA formation were obtained with variable frequency for four of the six soils tested and for three types of enrichment culture, designed to encourage growth of nitrate-reducing, methane-producing or fermentative bacteria. The identity of the volatile antimony compound produced in each of the three types of enrichment culture was confirmed by gas chromatography-mass spectrometry and gas chromatography-atomic absorption spectroscopy. There was no evidence of any other volatile antimony compound in the headspace gases. These data suggest that the capability to generate TMA is widely distributed in the terrestrial environment and is attributable to different metabolic types of micro-organisms.Item Metadata only Biomethylation of inorganic antimony by soil micro-organisms, Microbial biosystems(1998-08) Jenkins, R. O.; Craig, P. J.; Miller, D. P.; Stoop, L. C. A. M.; Ostah, N.; Morris, T. A.Item Metadata only Biomethylation of inorganic antimony compounds by an aerobic fungus: Scopulariopsis brevicaulis.(AMER CHEMICAL SOC, 1998) Jenkins, R. O.; Craig, P. J.; Goessler, W.; Miller, D. P.; Ostah, N.; Irgolic, K. J.Various metals and metalloids can be converted by a variety of microorganisms to their volatile methyl derivatives. These bioconversions are important from an environmental perspective because they take place over long time periods and the products have quite different properties (e.g., transportation, toxicological) as compared to the inorganic species from which they are derived. Whereas the biomethylation of arsenic is well established, that of the closely related element antimony is not, and there are no reports of antimony methylation by monoseptic microbial cultures. We report here, for the first time, the formation of trimethylantimony [(CH3)(3)Sb] by a characterized microorganism, Scopulariopsis brevicaulis, grown aerobically in the presence of inorganic antimony. Volatile antimony evolved into the headspace above the fungal cultures was quantified by remote trapping and analysis by inductively coupled plasma-mass spectrometry (ICP-MS). The existence of biogenic trimethylantimony was established, following exclusion of oxygen from cultures after growth, by remote trapping of volatile compounds and analysis by gas chromatography with compound-specific (mass spectrometry) or element-specific (atomic absorption) detection. No other volatile product containing antimony was detected in culture headspace gases.Item Metadata only Characterisation of microbial biotransformations of azo dyes(2000-04) Jenkins, R. O.; Betts, M. P.; Popova, S. V.; Arkhipova, M. B.; Ostah, N.; Dewhurst, F.; Tereshenko, L. N.; Craig, P. J.Item Metadata only Evaluation of cot mattress inner foam as a potential site for microbial generation of toxic gases.(Sage, 2000) Jenkins, R. O.; Morris, T-A; Craig, P. J.; Goessler, W.; Ostah, N.; Wills, K. M.Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot math ess samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylantimony together with physical adsorption of methylantimony forms to the polyurethane foam matrix could account for the apparent absence of "escaped" volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.Item Metadata only GC-MS characterisation of the microbial biovolatilisation of antimony(1998-08) Smith, L. M.; Jenkins, R. O.; Craig, P. J.; Ostah, N.; Miller, D. P.; Forster, S. N.Item Metadata only Influence of arsenic on antimony biomethylation by Cryptococcus humicolus(2003-09) Hartmann, L. M.; Craig, P. J.; Ostah, N.; Jenkins, R. O.Item Metadata only Mass spectrometry studies of organolead compounds(Wiley, 2001) Lawson, Graham; Ostah, N.Item Metadata only Microbial volatilisation of Group 15 elements(1998-03) Craig, P. J.; Jenkins, R. O.; Ostah, N.; Morris, T. A.; Miller, D. P.; Smith, L. M.; Forester, S. N.; Zafar, S.; Oakes, R. M.; Richie, A.Item Metadata only A microbiological basis for reductive generation of phosphine in Nature(1999-07) Jenkins, R. O.; Morris, T. A.; Craig, P. J.; Richie, A.; Ostah, N.Item Metadata only Occurrence, formation and fate of organoantimony compounds in the marine and terrestrial environment.(Springer-Verlag, 2000) Craig, P. J.; Forster, S. N.; Jenkins, R. O.; Miller, D. P.; Ostah, N.; Smith, L. M.; Morris, T-AItem Metadata only Phosphine generation by mixed- and monoseptic-cultures of anaerobic bacteria.(Elsevier, 2000) Jenkins, R. O.; Morris, T-A; Craig, P. J.; Ritchie, A. W.; Ostah, N.A microbial basis for bioreductive generation of phosphine is proposed, which could account at least in part for the presence of this toxic gas in natural anaerobic environments and in sewage and landfill gases. Phosphine generation under anaerobic growth conditions was dependent upon both the culture inoculum source (animal faeces) and enrichment culture conditions. Phosphine was detected in headspace gases from mixed cultures under conditions promoting fermentative growth of mixed acid and butyric acid bacteria, either in the presence or absence of methane generation. Monoseptic cultures of certain mixed acid fermenters (Escherichia coli, Salmonella gallinarum, and Salmonella arizonae) and solvent fermenters (Clostridium sporogenes, Clostridium acetobutyricum and Clostridium cochliarium) also generated phosphine. Such fermentative bacteria participate in the multi-stage process of methanogenesis in nature. Generation of phosphine by these bacteria, rather than by methanoarchaea themselves, could explain the apparent correlation between methanogenesis and the formation of phosphine in nature.Item Metadata only Speciation analysis of methylated antimony compounds.(Swiss Chemical Society, 1998) Miller, D. P.; Jenkins, R. O.; Ostah, N.; Morris, T-AItem Metadata only Speciation of biomethylation products from inorganic antimony compounds(1997-12) Morris, T. A.; Miller, D. P.; Craig, P. J.; Jenkins, R. O.; Ostah, N.Item Metadata only Speciation of biomethylation products from inorganic antimony compounds(1997-12) Morris, T. A.; Miller, D. P.; Craig, P. J.; Jenkins, R. O.; Ostah, N.Item Metadata only Towards speciation of organoantimony compounds in the environment(2000-09) Forster, S. N.; Craig, P. J.; Jenkins, R. O.; Ostah, N.; Sergeeva, T.; Morris, T. A.; Miller, D. P.; Sayago, A.Item Metadata only Use of mass spectroscopic techniques to elucidate the nature of the products of the oxidation of trimethylstibine in air.(John Wiley and Sons., 2001) Craig, P. J.; Forster, S. A.; Jenkins, R. O.; Lawson, Graham; Miller, D. P.; Ostah, N.Item Metadata only Use of mass spectroscopic techniques to elucidate the nature of the products of the oxidation of trimethylstibine in air.(2001-06) Craig, P. J.; Forster, S. A.; Jenkins, R. O.; Lawson, Graham; Miller, N.; Ostah, N.