Bacterial degradation and utilization of merbromine and fluorescein mercuric acetate.
01 Mar 1992-Bulletin of Environmental Contamination and Toxicology (Bull Environ Contam Toxicol)-Vol. 48, Iss: 3, pp 421-427
About: This article is published in Bulletin of Environmental Contamination and Toxicology.The article was published on 1992-03-01. It has received 4 citations till now. The article focuses on the topics: Fluorescein.
Citations
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TL;DR: Five nitrogen-fixing Azotobacter strains isolated from agricultural farms in West Bengal, India, were resistant to mercuric ion and organomercurials and NADPH and GSH might have a role in suppressing the inhibition of N 2 -fixation in the presence of Hg compounds.
Abstract: Five nitrogen-fixing Azotobacter strains isolated from agricultural farms in West Bengal, India, were resistant to mercuric ion and organomercurials. Resistance of Hg-resistant bacteria to mercury compounds is mediated by the activities of mercuric reductase and organomercurial lyase in the presence of NADPH and GSH as cofactors. These bacteria showed an extended lag phase in the presence of 10-50 μmol l -1 HgCl 2 . Nitrogen-fixing ability of these isolates was slightly inhibited when the mercury-resistant bacterial cells were preincubated with 10 μmol l -1 HgCl 2 . Acetylene reduction by these bacteria was significantly inhibited (91-97%) by 50 μmol l -1 HgCl 2 . However, when GSH and NADPH were added to the acetylene reduction assay mixture containing 50 nmol l -1 HgCl 2 , only 42-50% inhibition of nitrogenase activity was observed. NADPH and GSH might have a role in suppressing the inhibition of N 2 -fixation in the presence of Hg compounds either by assisting Hg-detoxifying enzymes to lower Hg concentration in the assay mixture or by formation of adduct comprising Hg and GSH which is unable to inhibit nitrogen fixation.
7 citations
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TL;DR: To determine whether the local application of mercurochrome over genital skin before surgery, in addition to soap/water scrubs, can help to decrease the incidence of infection patients undergoing hypospadias repair, and therebyThe incidence of fistula formation.
Abstract: Objective To determine whether the local application of mercurochrome over genital skin before surgery, in addition to soap/water scrubs, can help to decrease the incidence of infection patients undergoing hypospadias repair, and thereby the incidence of fistula formation.
Patients and methods The study comprised 44 consecutive boys undergoing primary or repeat surgery for hypospadias between October 1999 and April 2000. They were arbitrarily divided into two groups; group 1 received a conventional local scrub with soap/water 48 h before surgery and group 2, a conventional local scrub with soap/water was followed by a local application of 2% mercurochrome for 48 h before surgery. Both groups were comparable in age, location of the meatus and stage of repair. All patients were exposed to similar conditions during and after surgery. Urine, skin and wound swabs taken before during and after surgery were assessed microbiologically, using standard precautions. The incidence of infection and complications was then compared.
Results Mercurochrome significantly decreased local infection, especially before surgery, but its effect in decreasing fistula formation, although appreciable, was not statistically significant.
Conclusion The local application of mercurochrome after a soap/water scrub for at least 48 h before surgery is a simple, economic and effective means to decrease postoperative wound infection. Future studies are needed, keeping other determinants of fistula formation constant, to evaluate its role in decreasing fistula formation in patients undergoing hypospadias repair.
4 citations
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TL;DR: A study of the increased rate of the elimination of HgCl2 by Bacillus pasteurii strain DR2 from natural river water in the presence of organic compounds finds this bacteria has the dual characteristics of elimination of mercury compounds and utilization of aromatic compounds in natural conditions.
Abstract: Mercury (Hg) compounds are extensively used in agriculture as seed-dressers and pesiticides, in hospitals as disinfectants, in sewage treatment and in industries including pulp and paper and chlor-alkali industries as chemical catalysts. Several thousand millions of tons of mercury are dispersed into the environment every year. Rain water washes mercury from soils and rocks. In aquatic environments sediments are the richest deposits of mercury compounds. The mutagenicity and teratogenicity of these Hg-containing compounds are well-documented. This paper reports on a study of the increased rate of the elimination of HgCl2 by Bacillus pasteurii strain DR2 from natural river water in the presence of organic compounds. This bacteria has the dual characteristics of elimination of mercury compounds and utilization of aromatic compounds in natural conditions. 19 refs., 3 figs., 1 tab.
3 citations
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TL;DR: A broad spectrum mercury-resistant bacterial strain was isolated from contaminated water and was identified as Bacillus pasteurii strain DR2 as mentioned in this paper, which could volatilize Hg-compounds including organomercurials from its growth media.
Abstract: A broad-spectrum mercury-resistant bacterial strain was isolated from contaminated water and was identified as Bacillus pasteurii strain DR2. It could volatilize Hg-compounds including organomercurials from its growth media. It utilized several aromatic compounds as a sole source of carbon. The bacterial strain eliminated HgCl2 from sterile river water and the presence of benzene, toluene, naphthalene and nitrobenzene at 1 mM concentration in the system increased the rate of mercury volatilization, the volatilization rate being highest with benzene. When 1.7×107 cells of this bacterial strain were added per ml of non-sterile water the bacterial strain volatilized more than 90 percent of mercury from mercuric chloride and organo-mercurials like PMA, thiomersol and methoxy ethyl mercuric chloride (MEMC). In the absence of this bacterial strain the volatilization of PMA and MEMC due to the presence of other Hg-resistant organisms in nonsterile polluted water ranged between 20–25 percent and of HgCl2 was about 40 percent. However, in the presence of B. pasteurii DR2 volatilization of these Hg-compounds from non-sterile water increased by 20–40 percent. In the presence of 1 mM benzene the rate of mercury volatilization was even higher. In all the cases the rate of volatilization was higher in the first seven days than in the next seven days.
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References
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TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
Abstract: Since 1922 when Wu proposed the use of the Folin phenol reagent for the measurement of proteins, a number of modified analytical procedures utilizing this reagent have been reported for the determination of proteins in serum, in antigen-antibody precipitates, and in insulin. Although the reagent would seem to be recommended by its great sensitivity and the simplicity of procedure possible with its use, it has not found great favor for general biochemical purposes. In the belief that this reagent, nevertheless, has considerable merit for certain application, but that its peculiarities and limitations need to be understood for its fullest exploitation, it has been studied with regard to effects of variations in pH, time of reaction, and concentration of reactants, permissible levels of reagents commonly used in handling proteins, and interfering substances. Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
285,427 citations
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TL;DR: The mercury cycle in the biosphere and biological methylation of mercury and microbial resistance to mercury and organomercurials are studied.
Abstract: BIOTRANSFORMA nONS OF TOXIC MET AL CAnONS . Mercury . The mercury cycle in the biosphere .. Biological methylation of mercury . Microbial resistance to mercury and organomercurials .
409 citations
"Bacterial degradation and utilizati..." refers background in this paper
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TL;DR: It is shown that under aerobic conditions, methylmercury formation under Anaerobic conditions and under Aerobic conditions is more stable than under either of the other conditions.
Abstract: METHYLATION OF MERCURY BY MICROORGANISMS ..................................... 96 Mechanism of Methylation of Mercury....................................................... 96 Methylmercury Formation Under Anaerobic Conditions ........................................ 97 Methylmercury Formation Under Aerobic Conditions .......................................... 97 Effects of HgS on Methylation of Mercury .......... .......................................... 98
330 citations
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TL;DR: It was shown that mercuric reductase has the capacity to accept four electrons per FAD-containing subunit, and that two thiols become kinetically titrable by 5,5'-dithiobis-(2-nitrobenzoate) upon reduction with NADPH, characteristic features of the disulfide reduct enzyme class of flavoproteins.
Abstract: The flavoprotein mercuric reductase catalyzes the two-electron reduction of mercuric ions to elemental mercury using NADPH as an electron donor. It has now been purified from Pseudomonas aeruginosa PAO9501 carrying the plasmid pVS1. In this plasmid system, where the mer operon is on the transposon Tn501, mercuric reductase comprises up to 6% of the soluble cellular protein upon induction with mercurials. The purification is a rapid (two-step), high yield (80%) procedure. Anaerobic titrations of mercuric reductase with dithionite revealed the formation of a charge transfer complex with an absorbance maximum around 540 nm. Striking spectroscopic similarities to lipoamide dehydrogenase and glutathione reductase were observed. These two enzymes, which catalyze the transfer of electrons between pyridine nucleotides and disulfides, are flavoproteins which contain an oxidation-reduction-active cysteine residue at the active site. The expectation that mercuric reductase contains a similar electron acceptor was confirmed when it was shown that mercuric reductase has the capacity to accept four electrons per FAD-containing subunit, and that two thiols become kinetically titrable by 5,5'-dithiobis-(2-nitrobenzoate) upon reduction with NADPH. These are characteristic features of the disulfide reductase class of flavoproteins. Further similarities with at least one of these enzymes, lipoamide dehydrogenase, include the E/EH2 midpoint potential (-269 mV), fluorescence properties, and extinction coefficients of E and EH2. Preliminary observations relevant to an understanding of the mechanism of mercuric reductase are discussed.
251 citations
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TL;DR: A strain of Escherichia coli carrying genes determining mercury resistance on a naturally occurring resistance transfer factor (RTF) converts 95% of 10(-5)m Hg(2+) (chloride) to metallic mercury at a rate of 4 to 5 nmoles of Hg (2+) per min per 10(8) cells.
Abstract: A strain of Escherichia coli carrying genes determining mercury resistance on a naturally occurring resistance transfer factor (RTF) converts 95% of 10−5m Hg2+ (chloride) to metallic mercury at a rate of 4 to 5 nmoles of Hg2+ per min per 108 cells. The metallic mercury is rapidly eliminated from the culture medium as mercury vapor. The volatilizing activity has a temperature dependence and heat sensitivity characteristic of enzymatic catalysis and is inducible by mercuric chloride. Ag+ and Au3+ are markedly inhibitory of mercury volatilization.
192 citations