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Wehmeier S, Preihs M, Dressler J, Raab A, Feldmann J. Detection of inorganic arsenic in rice using a field-deployable method with Cola extraction. Anal Bioanal Chem 2024; 416:2677-2682. [PMID: 37994920 PMCID: PMC11009735 DOI: 10.1007/s00216-023-05041-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/24/2023]
Abstract
Rice is a staple food and known to accumulate inorganic arsenic (iAs), which is a class 1 carcinogen to humans. Arsenic field-deployable method kits, designed for water testing, are able to screen iAs in rice, to assure food safety and quick decision-making without the need for laboratory analysis. For the arsenic extraction within the field method, nitric acid is used. To make the field method on-site safer, cost-effective and easier to handle, the method was adapted using a Cola in the extraction process. The adapted field-deployable method was tested by screening a total of 30 rice and rice products from the Austrian market. To verify the results obtained by the Cola extraction field-deployable method, the obtained iAs concentration was compared to HPLC-ICP-MS results. The Cola extraction field method obtained an LOD of 39 µg iAs kg-1 rice, and with an average reproducibility of 14% RSD, the method was capable of recording no false-negative but 7% false-positive values at the 2023 updated European Commission (EC) limits for rice. All, but one, screened rice samples were within the EU limits for iAs in rice and rice products.
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Affiliation(s)
- Silvia Wehmeier
- Institute of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria.
| | - Marc Preihs
- Institute of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
| | - Julia Dressler
- Institute of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
- Institute of Inorganic and Analytical Chemistry, Westfaelische Wilhelms-University Muenster, Munster, Germany
| | - Andrea Raab
- Institute of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
| | - Jörg Feldmann
- Institute of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
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Giuraniuc CV, Parkin C, Almeida MC, Fricker M, Shadmani P, Nye S, Wehmeier S, Chawla S, Bedekovic T, Lehtovirta-Morley L, Richards DM, Gow NA, Brand AC. Dynamic calcium-mediated stress response and recovery signatures in the fungal pathogen, Candida albicans. mBio 2023; 14:e0115723. [PMID: 37750683 PMCID: PMC10653887 DOI: 10.1128/mbio.01157-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/07/2023] [Indexed: 09/27/2023] Open
Abstract
IMPORTANCE Intracellular calcium signaling plays an important role in the resistance and adaptation to stresses encountered by fungal pathogens within the host. This study reports the optimization of the GCaMP fluorescent calcium reporter for live-cell imaging of dynamic calcium responses in single cells of the pathogen, Candida albicans, for the first time. Exposure to membrane, osmotic or oxidative stress generated both specific changes in single cell intracellular calcium spiking and longer calcium transients across the population. Repeated treatments showed that calcium dynamics become unaffected by some stresses but not others, consistent with known cell adaptation mechanisms. By expressing GCaMP in mutant strains and tracking the viability of individual cells over time, the relative contributions of key signaling pathways to calcium flux, stress adaptation, and cell death were demonstrated. This reporter, therefore, permits the study of calcium dynamics, homeostasis, and signaling in C. albicans at a previously unattainable level of detail.
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Affiliation(s)
- C. V. Giuraniuc
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - C. Parkin
- MRC Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - M. C. Almeida
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - M. Fricker
- School of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - P. Shadmani
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - S. Nye
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - S. Wehmeier
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - S. Chawla
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - T. Bedekovic
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
- MRC Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - L. Lehtovirta-Morley
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
| | - D. M. Richards
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
- Department of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - N. A. Gow
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
- MRC Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - A. C. Brand
- School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, United Kingdom
- MRC Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
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Dressler JM, Raab A, Wehmeier S, Feldmann J. Arsenic, cadmium, and lead in rice and rice products on the Austrian market. Food Additives & Contaminants: Part B 2023; 16:185-195. [PMID: 37013463 DOI: 10.1080/19393210.2023.2194061] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Fifty-one rice samples, i.e. 25 rice varieties, 8 rice products, and 18 rice containing baby foods from the Austrian market were surveyed for arsenic, cadmium, and lead. Inorganic arsenic (iAs) is most toxic to human health, and its mean concentrations in rice were 120 µg kg-1, 191 µg kg-1 in rice products, and 77 µg kg-1 in baby foods. The average dimethylarsinic acid and methylarsonic acid concentrations were 56 µg kg-1 and 2 µg kg-1, respectively. The highest iAs concentration was found in rice flakes (237 ± 15 µg kg-1), close to the Maximum Level (ML) set by the EU regulation for husked rice (250 µg kg-1). The levels of cadmium (12 to 182 µg kg-1) and lead (6 to 30 µg kg-1) in the majority of rice samples were below the European ML. Upland grown rice from Austria showed both, low inorganic arsenic (<19 µg kg-1) and cadmium (<38 µg kg-1) concentrations.
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Affiliation(s)
- Julia Monika Dressler
- Institute of Inorganic and Analytical Chemistry, Westfaelische Wilhelms-University Muenster, Munster, Germany
- Department of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
| | - Andrea Raab
- Department of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
| | - Silvia Wehmeier
- Department of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
| | - Jörg Feldmann
- Department of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria
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Wehmeier S, Morrison E, Plato A, Raab A, Feldmann J, Bedekovic T, Wilson D, Brand AC. Multi trace element profiling in pathogenic and non-pathogenic fungi. Fungal Biol 2020; 124:516-524. [PMID: 32389315 PMCID: PMC7232024 DOI: 10.1016/j.funbio.2020.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/25/2020] [Accepted: 03/03/2020] [Indexed: 12/14/2022]
Abstract
Maintaining appropriate levels of trace elements during infection of a host is essential for microbial pathogenicity. Here we compared the uptake of 10 trace elements from 3 commonly-used laboratory media by 3 pathogens, Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, and a model yeast, Saccharomyces cerevisiae. The trace element composition of the yeasts, C. albicans, C. neoformans and S. cerevisiae, grown in rich (YPD) medium, differed primarily in P, S, Fe, Zn and Co. Speciation analysis of the intracellular fraction, which indicates the size of the organic ligands with which trace elements are complexed, showed that the ligands for S were similar in the three fungi but there were significant differences in binding partners for Fe and Zn between C. neoformans and S.cerevisiae. The profile for Cu varied across the 3 yeast species. In a comparison of C. albicans and A. fumigatus hyphae, the former showed higher Fe, Cu, Zn and Mn, while A. fumigatus contained higher P, S Ca and Mo. Washing C. albicans cells with the cell-impermeable chelator, EGTA, depleted 50–90 % of cellular Ca, suggesting that a large proportion of this cation is stored in the cell wall. Treatment with the cell wall stressor, Calcofluor White (CFW), alone had little effect on the elemental profile whilst combined Ca + CFW stress resulted in high cellular Cu and very high Ca. Together our data enhance our understanding of trace element uptake by pathogenic fungi and provide evidence for the cell wall as an important storage organelle for Ca.
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Affiliation(s)
- Silvia Wehmeier
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Emma Morrison
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Anthony Plato
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Andrea Raab
- TESLA, School of Natural and Computing Sciences, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, UK
| | - Jörg Feldmann
- TESLA, School of Natural and Computing Sciences, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, UK
| | - Tina Bedekovic
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK; Medical Research Council Centre for Medical Mycology at the University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Alexandra C Brand
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK; Medical Research Council Centre for Medical Mycology at the University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
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Thomson DD, Wehmeier S, Byfield FJ, Janmey PA, Caballero-Lima D, Crossley A, Brand AC. Contact-induced apical asymmetry drives the thigmotropic responses of Candida albicans hyphae. Cell Microbiol 2014; 17:342-54. [PMID: 25262778 PMCID: PMC4371639 DOI: 10.1111/cmi.12369] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/02/2014] [Accepted: 09/08/2014] [Indexed: 11/30/2022]
Abstract
Filamentous hyphae of the human pathogen, Candida albicans, invade mucosal layers and medical silicones. In vitro, hyphal tips reorient thigmotropically on contact with small obstacles. It is not known how surface topography is sensed but hyphae lacking the cortical marker, Rsr1/Bud1, are unresponsive. We show that, on surfaces, the morphology of hyphal tips and the position of internal polarity protein complexes are asymmetrically skewed towards the substratum and biased towards the softer of two surfaces. In nano-fabricated chambers, the Spitzenkörper (Spk) responded to touch by translocating across the apex towards the point of contact, where its stable maintenance correlated with contour-following growth. In the rsr1Δ mutant, the position of the Spk meandered and these responses were attenuated. Perpendicular collision caused lateral Spk oscillation within the tip until after establishment of a new growth axis, suggesting Spk position does not predict the direction of growth in C. albicans. Acute tip reorientation occurred only in cells where forward growth was countered by hyphal friction sufficient to generate a tip force of ∼ 8.7 μN (1.2 MPa), more than that required to penetrate host cell membranes. These findings suggest mechanisms through which the organization of hyphal tip growth in C. albicans facilitates the probing, penetration and invasion of host tissue.
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Affiliation(s)
- Darren D Thomson
- School of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK; Institute for Biology Valrose, University of Nice-Sophia Antipolis, Nice, France
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Ene IV, Adya AK, Wehmeier S, Brand AC, MacCallum DM, Gow NAR, Brown AJP. Host carbon sources modulate cell wall architecture, drug resistance and virulence in a fungal pathogen. Cell Microbiol 2012; 14:1319-35. [PMID: 22587014 PMCID: PMC3465787 DOI: 10.1111/j.1462-5822.2012.01813.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/19/2012] [Accepted: 05/09/2012] [Indexed: 11/27/2022]
Abstract
The survival of all microbes depends upon their ability to respond to environmental challenges. To establish infection, pathogens such as Candida albicans must mount effective stress responses to counter host defences while adapting to dynamic changes in nutrient status within host niches. Studies of C. albicans stress adaptation have generally been performed on glucose-grown cells, leaving the effects of alternative carbon sources upon stress resistance largely unexplored. We have shown that growth on alternative carbon sources, such as lactate, strongly influence the resistance of C. albicans to antifungal drugs, osmotic and cell wall stresses. Similar trends were observed in clinical isolates and other pathogenic Candida species. The increased stress resistance of C. albicans was not dependent on key stress (Hog1) and cell integrity (Mkc1) signalling pathways. Instead, increased stress resistance was promoted by major changes in the architecture and biophysical properties of the cell wall. Glucose- and lactate-grown cells displayed significant differences in cell wall mass, ultrastructure, elasticity and adhesion. Changes in carbon source also altered the virulence of C. albicans in models of systemic candidiasis and vaginitis, confirming the importance of alternative carbon sources within host niches during C. albicans infections.
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Affiliation(s)
- Iuliana V Ene
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
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Haag AF, Wehmeier S, Muszyński A, Kerscher B, Fletcher V, Berry SH, Hold GL, Carlson RW, Ferguson GP. Biochemical characterization of Sinorhizobium meliloti mutants reveals gene products involved in the biosynthesis of the unusual lipid A very long-chain fatty acid. J Biol Chem 2011; 286:17455-66. [PMID: 21454518 PMCID: PMC3093819 DOI: 10.1074/jbc.m111.236356] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 03/25/2011] [Indexed: 11/06/2022] Open
Abstract
Sinorhizobium meliloti forms a symbiosis with the legume alfalfa, whereby it differentiates into a nitrogen-fixing bacteroid. The lipid A species of S. meliloti are modified with very long-chain fatty acids (VLCFAs), which play a central role in bacteroid development. A six-gene cluster was hypothesized to be essential for the biosynthesis of VLCFA-modified lipid A. Previously, two cluster gene products, AcpXL and LpxXL, were found to be essential for S. meliloti lipid A VLCFA biosynthesis. In this paper, we show that the remaining four cluster genes are all involved in lipid A VLCFA biosynthesis. Therefore, we have identified novel gene products involved in the biosynthesis of these unusual lipid modifications. By physiological characterization of the cluster mutant strains, we demonstrate the importance of this gene cluster in the legume symbiosis and for growth in the absence of salt. Bacterial LPS species modified with VLCFAs are substantially less immunogenic than Escherichia coli LPS species, which lack VLCFAs. However, we show that the VLCFA modifications do not suppress the immunogenicity of S. meliloti LPS or affect the ability of S. meliloti to induce fluorescent plant defense molecules within the legume. Because VLCFA-modified lipids are produced by other rhizobia and mammalian pathogens, these findings will also be important in understanding the function and biosynthesis of these unusual fatty acids in diverse bacterial species.
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Affiliation(s)
- Andreas F. Haag
- From the School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom and
| | - Silvia Wehmeier
- From the School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom and
| | - Artur Muszyński
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | | | - Vivien Fletcher
- From the School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom and
| | - Susan H. Berry
- From the School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom and
| | - Georgina L. Hold
- From the School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom and
| | - Russell W. Carlson
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Gail P. Ferguson
- From the School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom and
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Wehmeier S, Arnold MFF, Marlow VL, Aouida M, Myka KK, Fletcher V, Benincasa M, Scocchi M, Ramotar D, Ferguson GP. Internalization of a thiazole-modified peptide in Sinorhizobium meliloti occurs by BacA-dependent and -independent mechanisms. Microbiology (Reading) 2010; 156:2702-2713. [PMID: 20507886 DOI: 10.1099/mic.0.039909-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BacA proteins play key roles in the chronic intracellular infections of Sinorhizobium meliloti, Brucella abortus and Mycobacterium tuberculosis within their respective hosts. S. meliloti, B. abortus and M. tuberculosis BacA-deficient mutants have increased resistance to the thiazole-modified peptide bleomycin. BacA has been previously hypothesized, but not experimentally verified, to be involved in bleomycin uptake. In this paper, we show that a BacA-dependent mechanism is the major route of bleomycin internalization in S. meliloti. We also determined that the B. abortus and S. meliloti BacA proteins are functional homologues and that the B. abortus BacA protein is involved in the uptake of both bleomycin and proline-rich peptides. Our findings also provide evidence that there is a second, BacA-independent minor mechanism for bleomycin internalization in S. meliloti. We determined that the BacA-dependent and -independent mechanisms of bleomycin uptake are energy-dependent, consistent with both mechanisms of bleomycin uptake involving transport systems.
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Affiliation(s)
- Silvia Wehmeier
- School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Markus F F Arnold
- School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Victoria L Marlow
- School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Mustapha Aouida
- Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, 5415, Boul. de l'Assomption, Montreal, QC H1T 2M4, Canada
| | - Kamila K Myka
- School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Vivien Fletcher
- School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Monica Benincasa
- Department of Life Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy
| | - Marco Scocchi
- Department of Life Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy
| | - Dindial Ramotar
- Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, 5415, Boul. de l'Assomption, Montreal, QC H1T 2M4, Canada
| | - Gail P Ferguson
- School of Medicine and Dentistry, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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Wehmeier S, Varghese AS, Gurcha SS, Tissot B, Panico M, Hitchen P, Morris HR, Besra GS, Dell A, Smith MCM. Glycosylation of the phosphate binding protein, PstS, in Streptomyces coelicolor by a pathway that resembles protein O-mannosylation in eukaryotes. Mol Microbiol 2008; 71:421-33. [PMID: 19017269 DOI: 10.1111/j.1365-2958.2008.06536.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previously mutations in a putative protein O-mannosyltransferase (SCO3154, Pmt) and a polyprenol phosphate mannose synthase (SCO1423, Ppm1) were found to cause resistance to phage, phiC31, in the antibiotic producing bacteria Streptomyces coelicolor A3(2). It was proposed that these two enzymes were part of a protein O-glycosylation pathway that was necessary for synthesis of the phage receptor. Here we provide the evidence that Pmt and Ppm1 are indeed both required for protein O-glycosylation. The phosphate binding protein PstS was found to be glycosylated with a trihexose in the S. coelicolor parent strain, J1929, but not in the pmt(-) derivative, DT1025. Ppm1 was necessary for the transfer of mannose to endogenous polyprenol phosphate in membrane preparations of S. coelicolor. A mutation in ppm1 that conferred an E218V substitution in Ppm1 abolished mannose transfer and glycosylation of PstS. Mass spectrometry analysis of extracted lipids showed the presence of a glycosylated polyprenol phosphate (PP) containing nine repeated isoprenyl units (C(45)-PP). S. coelicolor membranes were also able to catalyse the transfer of mannose to peptides derived from PstS, indicating that these could be targets for Pmt in vivo.
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Affiliation(s)
- S Wehmeier
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
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Abstract
Antimony is distributed in the environment in inorganic and organic species with different solubility and mobility characters. Here we investigate the transformation of antimony in view of biomethylation during sewage sludge fermentation as a case study for an anaerobic environment. Our approach was to identify if antimony methylation follows the Challenger pathway by using isotopically enriched antimonite (123Sb(v)). The antimony source was subjected to methylation in sewage sludge, an anaerobic dominant methanogenic Archaea community. The antimony species were determined in the gas phase using cryotrapping (CT)-GC-ICP-MS, and in the medium (sewage slude) by hydride generation (HG) prior CT-GC-ICP-MS. The determined 123/121Sb isotope ratios in the volatile trimethylstibine and non-volatile methylantimony species indicated that the methylation follows the proposed methylation pathway. With this approach we were able to quantify 123Sb incorporation into monomethyl-, dimethyl- and trimethylantimony, respectively. The incorporation decreased with further methylation from 91% to 82% and 73%. Volatilisation as trimethystibine was generally lower than 0.1%, however, up to 0.8% of added antimony was found methylated to methylantimony species and mainly accumulated in the cell. Moreover, antimony biomethylation was enhanced by stimulation of the anaerobic communities of methanogenic Archaea and sulfate reducing bacteria (SRB), with the methanogens showing a higher activity.
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Affiliation(s)
- Silvia Wehmeier
- Institute of Medical Sciences, Department of Molecular and Cell Biology, University of Aberdeen, Foresterhill, AberdeenUKAB25 2ZD
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Wehmeier S, Raab A, Feldmann J. Investigations into the role of methylcobalamin and glutathione for the methylation of antimony using isotopically enriched antimony(V). Appl Organomet Chem 2004. [DOI: 10.1002/aoc.692] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Holland G, Tanner SD, Wehmeier S, Ellam R, Feldmann J. Calculation methods for the determination of isotope ratios of transient signals of volatile organometallic compounds. Plasma Source Mass Spectrometry 2003. [DOI: 10.1039/9781847551689-00231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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