The isolation and initial characterization of mercury resistant chemolithotrophic thermophilic bacteria from mercury rich geothermal springs

Chatziefthimiou, Aspassia D.; Crespo‐Medina, Melitza; Wang, Yanping; Vetriani, Costantino; Barkay, Tamar

doi:10.1007/s00792-007-0065-2

Cited by 49 publications

(26 citation statements)

References 40 publications

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“…Two separate set of primers are needed for Gram-negative and Gram-positive bacteria as the sequence of merA gene differs among species (Chatziefthimiou et al 2007). The mer genes can be located in plasmids, chromosomes and have also been identified as components of transposons and integrons (Zeyaullah et al 2010).…”

Section: Primers Help Identify Mercury Resistant Determinants Among Bmentioning

confidence: 99%

Bacterial mer operon-mediated detoxification of mercurial compounds: a short review

2011

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Mercury pollution has emerged as a major problem in industrialized zones and presents a serious threat to environment and health of local communities. Effectiveness and wide distribution of mer operon by horizontal and vertical gene transfer in its various forms among large community of microbe reflect importance and compatibility of this mechanism in nature. This review specifically describes mer operon and its generic molecular mechanism with reference to the central role played by merA gene and its related gene products. The combinatorial action of merA and merB together maintains broad spectrum mercury detoxification system for substantial detoxification of mercurial compounds. Feasibility of mer operon to coexist with antibiotic resistance gene (ampr, kanr, tetr) clusters enables extensive adaptation of bacterial species to adverse environment. Flexibility of the mer genes to exist as intricate part of chromosome, plasmids, transposons, and integrons enables high distribution of these genes in wider microbial gene pool. Unique ability of this system to manipulate oligodynamic property of mercurial compounds for volatilization of mercuric ions (Hg2+) makes it possible for a wide range of microbes to tolerate mercury-mediated toxicity.

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Section: Primers Help Identify Mercury Resistant Determinants Among Bmentioning

confidence: 99%

Bacterial mer operon-mediated detoxification of mercurial compounds: a short review

2011

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“…The high exposure of toxic heavy metals causes the cells of microorganisms develop resistance mechanisms and metalion homeostasis (Aspassia et al 2007). Several scientific reports stated that most indigenous microorganisms tolerate high concentrations of heavy metal and may play a significant role in bioremediation soil (Ge et al 2009).…”

Section: Introductionmentioning

confidence: 99%

The potential capability of bacteria and yeast strains isolated from Rungkut Industrial Sewage in Indonesia as a bioaccumulators and biosorbents of copper

et al. 2017

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Abstract. Irawati W, Parhusip Ajn, Christian S, Yuwono T. 2017. The potential capability of bacteria and yeast strains isolated from Rungkut Industrial Sewage in Indonesia as a bioaccumulators and biosorbents of copper. . Heavy metal pollution is a serious problem as a result of industrialization due to the high production of wastewaters containing high concentrations of heavy metals. Wastewater contains microbial populations adapted to the toxic concentrations of heavy metals and becomes resistant by accumulating copper inside the cells. The aims of the study were to isolate yeast and bacteria from Rungkut Industrial sewage in Indonesia, and to examine the capability of these isolates to accumulate and biosorb copper. The copper resistance was determined by measuring minimum inhibitory concentration (MIC). The capability of isolates to accumulate and biosorb copper were determined by atomic absorption spectrophotometer. Biosorption is described as how much copper is removed from a growth medium with reference to the initial concentration. Of this study, nine bacterial strains and eight yeast strains were obtained with the MICs of 6-7 mM, and 16-20 mM CuSO 4 , respectively. Afterward, we have successfully selected three bacteria and one yeast strains showing the highest copper resistance. The three bacterial strains, designated as C1, C2, and C4 were able to accumulate copper up to 29.93, 508.01, 371.42 mg/cell dry weight, respectively. While the yeast strain, ES9.3 was able to accumulate 0.52 mg/cell dry weight and reduce up to 82.32% copper concentration in the medium. The findings of this study indicated that yeast and bacterial strains were promising microorganisms for removal of copper.

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“…Mercury-resistant microbes were readily isolated from deep-sea hydrothermal vents (48) and terrestrial hot springs (10,43), and their distribution suggested a role in adaptation to Hg toxicity. Culture-independent techniques detected mer genes in Yellowstone National Park (YNP) (50) and Coso Hot Springs, CA (43).…”

mentioning

confidence: 99%

Mercury Resistance and Mercuric Reductase Activities and Expression among Chemotrophic Thermophilic Aquificae

Freedman

Zhu

Barkay

2012

Appl Environ Microbiol

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ABSTRACTMercury (Hg) resistance (mer) by the reduction of mercuric to elemental Hg is broadly distributed among theBacteriaandArchaeaand plays an important role in Hg detoxification and biogeochemical cycling. MerA is the protein subunit of the homodimeric mercuric reductase (MR) enzyme, the central function of themersystem. MerA sequences in the phylumAquificaeform the deepest-branching lineage in Bayesian phylogenetic reconstructions of all known MerA homologs. We therefore hypothesized that themerAhomologs in two thermophilicAquificae,Hydrogenobaculumsp. strain Y04AAS1 (AAS1) andHydrogenivirgasp. strain 128-5-R1-1 (R1-1), specified Hg resistance. Results supported this hypothesis, because strains AAS1 and R1-1 (i) were resistant to >10 μM Hg(II), (ii) transformed Hg(II) to Hg(0) during cellular growth, and (iii) possessed Hg-dependent NAD(P)H oxidation activities in crude cell extracts that were optimal at temperatures corresponding with the strains' optimal growth temperatures, 55°C for AAS1 and 70°C for R1-1. While these characteristics all conformed with themersystem paradigm, expression of theAquificaemeroperons was not induced by exposure to Hg(II) as indicated by unity ratios ofmerAtranscripts, normalized togyrAtranscripts for hydrogen-grown AAS1 cultures, and by similar MR specific activities in thiosulfate-grown cultures with and without Hg(II). The Hg(II)-independent expression ofmerin the deepest-branching lineage of MerA from bacteria whose natural habitats are Hg-rich geothermal environments suggests that regulated expression ofmerwas a later innovation likely in environments where microorganisms were intermittently exposed to toxic concentrations of Hg.

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The isolation and initial characterization of mercury resistant chemolithotrophic thermophilic bacteria from mercury rich geothermal springs

Cited by 49 publications

References 40 publications

Bacterial mer operon-mediated detoxification of mercurial compounds: a short review

Bacterial mer operon-mediated detoxification of mercurial compounds: a short review

The potential capability of bacteria and yeast strains isolated from Rungkut Industrial Sewage in Indonesia as a bioaccumulators and biosorbents of copper

Mercury Resistance and Mercuric Reductase Activities and Expression among Chemotrophic Thermophilic Aquificae

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