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Restrepo Cordoba MA, Barton PJ, Bayes-Genis A, Govind R, Serrano I, Midwinter W, Pascual-Figal D, Wilk A, Garcia Pinilla JM, Cook SA, Provencio M, Lyon A, Alonso-Pulpon L, Ware JS, Garcia-Pavia P. P1503Genetic predisposing factors in chemotherapy-induced cardiomyopathy. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p1503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - P J Barton
- Royal Brompton Hospital, London, United Kingdom
| | - A Bayes-Genis
- Germans Trias i Pujol Hospital, Badalona (Barcelona), Spain
| | - R Govind
- Royal Brompton Hospital, London, United Kingdom
| | - I Serrano
- Hospital Universitario Joan XXIII, Tarragona, Spain
| | - W Midwinter
- Royal Brompton Hospital, London, United Kingdom
| | - D Pascual-Figal
- Hospital Clínico Univeristario Virgen de la Arrixaca, Murcia, Spain
| | - A Wilk
- Royal Brompton Hospital, London, United Kingdom
| | | | - S A Cook
- Royal Brompton Hospital, London, United Kingdom
| | - M Provencio
- University Hospital Puerta de Hierro Majadahonda, Medical Oncology Department, Madrid, Spain
| | - A Lyon
- Royal Brompton Hospital, London, United Kingdom
| | - L Alonso-Pulpon
- University Hospital Puerta de Hierro Majadahonda, Cardiology, Madrid, Spain
| | - J S Ware
- Royal Brompton Hospital, London, United Kingdom
| | - P Garcia-Pavia
- University Hospital Puerta de Hierro Majadahonda, Cardiology, Madrid, Spain
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Abstract
Clostridium difficile toxin synthesis is growth phase-dependent and is regulated by various environmental signals. The toxin genes tcdA and tcdB are located in a pathogenicity locus, which also includes three accessory genes, tcdR, tcdC and tcdE. TcdR has been shown to act as an alternative σ factor that mediates positive regulation of both the toxin genes and its own gene. The tcdA, tcdB and tcdR genes are transcribed during the stationary growth phase. The tcdC gene, however, is expressed during exponential phase. This expression pattern suggested that TcdC may act as a negative regulator of toxin gene expression. TcdC is a small acidic protein without any conserved DNA-binding motif. It is able to form dimers and its N-terminal region includes a putative transmembrane domain. Genetic and biochemical evidence showed that TcdC negatively regulates C. difficile toxin synthesis by interfering with the ability of TcdR-containing RNA polymerase to recognize the tcdA and tcdB promoters. In addition, the C. difficile NAP1/027 epidemic strains that produce higher levels of toxins have mutations in tcdC. Interestingly, a frameshift mutation at position 117 of the tcdC coding sequence seems to be, at least in part, responsible for the hypertoxigenicity phenotype of these epidemic strains.
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Affiliation(s)
- B. Dupuy
- Unité des Toxines et Pathogénie Bactérienne, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - R. Govind
- Unité des Toxines et Pathogénie Bactérienne, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - A. Antunes
- Unité des Toxines et Pathogénie Bactérienne, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - S. Matamouros
- Unité des Toxines et Pathogénie Bactérienne, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
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Bernstein J, Govind R. Development of a novel air quality sensor. J Allergy Clin Immunol 2005. [DOI: 10.1016/j.jaci.2004.12.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Utgikar VP, Chen BY, Chaudhary N, Tabak HH, Haines JR, Govind R. Acute toxicity of heavy metals to acetate-utilizing mixed cultures of sulfate-reducing bacteria: EC100 and EC50. Environ Toxicol Chem 2001; 20:2662-2669. [PMID: 11764146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the heavy metals at concentrations below EC100. The 7-d EC50 values obtained from the difference between the dissolved metal concentrations for the control tubes (tubes not containing copper or zinc) and tubes containing metals were found to be 10.5 mg/L for copper and 16.5 mg/L for zinc. Measurements of the turbidity and pH, bacterial population estimations by means of a most-probable number technique, and metal recovery in the sulfide precipitate were found to have only a limited applicability in these determinations.
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Affiliation(s)
- V P Utgikar
- Land Remediation and Pollution Control Division, National Risk Management Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268 USA
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Tabak HH, Govind R. Bioavailability and biodegradation kinetics protocol for organic pollutant compounds to achieve environmentally acceptable endpoints during bioremediation. Ann N Y Acad Sci 1997; 829:36-61. [PMID: 9472313 DOI: 10.1111/j.1749-6632.1997.tb48564.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This paper is an extension of our previous studies on quantitating biodegradation kinetics in soil slurry and compacted soil systems. Previous studies had mainly used phenol as a test contaminant. Phenol represents hydrophilic compounds which exhibit high water solubility and low soil sorption characteristics. This paper extends the experimental protocol using polycyclic aromatic hydrocarbons (PAHs) as the test contaminants. PAHs are hydrophobic compounds with low water solubility and exhibit significant partitioning in soil organic carbon. Degradation rates of PAHs are much slower, thereby requiring acclimation of indigenous soil microbiota using microcosm reactors. The experimental protocol, elaborated in this paper, results in the measurement of biokinetic parameters which can be used to quantitate both ex situ and in situ bioremediation rates and assess the attainable endpoints. Biodegradation studies were conducted for naphthalene using soil slurry, soil wafer, and soil column reactors. Microcosm reactors were set-up to acclimate soil microbiota, and carbon dioxide evolution was used as a measure of acclimation. It was found that reasonable degree of PAH acclimation was achieved after 250 days of microcosm operation. Abiotic adsorption/desorption studies showed that equilibrium was achieved in about 20 hours and approximately 45% of the initial amount of naphthalene is adsorbed by the time equilibrium is attained. Further, desorption was much slower than adsorption with equilibrium being attained in 40 hours. Biokinetic parameters were derived from the cumulative oxygen uptake data of soil slurry, wafer, and column reactors using detailed mathematical models. The cumulative oxygen uptake in all three reactors were almost the same, since naphthalene primarily degraded in the soil phase and the extent of degradation in the aqueous phase was small.
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Affiliation(s)
- H H Tabak
- NRMRL, ORD, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA
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Tabak H, Govind R, Fu C, Yan X, Gao C, Pfanstiel S. Development of Bioavailability and Biokinetics Determination Methods for Organic Pollutants in Soil to Enhance In-Situ and On-Site Bioremediation. Biotechnol Prog 1997. [DOI: 10.1021/bp9600851] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ilias S, Govind R. Fouling of Thin-Channel and Tubular Membrane Modules by Dilute Suspensions. SEP SCI TECHNOL 1988. [DOI: 10.1080/01496398808075661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- S. Ilias
- a Department of Chemical Engineering , University of Cincinnati , Cincinnati , Ohio , 45221
| | - R. Govind
- a Department of Chemical Engineering , University of Cincinnati , Cincinnati , Ohio , 45221
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Puri SK, Govind R, Saxena AK, Dutta GP. Causal prophylactic activity of antibiotics against Plasmodium gallinaceum infection. Indian J Med Res 1981; 73 Suppl:36-40. [PMID: 7287092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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