Identification of three merB genes and characterization of a broad-spectrum mercury resistance module encoded by a class II transposon of Bacillus megaterium strain MB1

Huang, Chieh-Chen; Narita, Masaru; Yamagata, T.; Endo, Ginro

doi:10.1016/s0378-1119(99)00388-1

Cited by 52 publications

(53 citation statements)

References 21 publications

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“…The bar at the bottom reflects 5% difference. (Wang et al, 1987) and B. megaterium (Huang et al, 1999) confirmed that Firmicutes type merA primers, Fi-Fw/Fi-Rv1832 and Fi-Fw/Fi-Rv1892, resulted in amplicons of approximately 395 and 455 bp, respectively (data not shown). The b/g-type new primers worked with pDU1358 merA (Griffin et al, 1987) (data not shown).…”

Section: Resultsmentioning

confidence: 72%

“…Three different merA genes originating from Staphylococcus aureus pI258 (Laddaga et al, 1987), Bacillus sp. RC607 (Wang et al, 1987) and Bacillus megaterium MB1 (Huang et al, 1999), all cloned into Escherichia coli vectors (pRAL2, pYW40 and pGB3A, respectively, kind gift of Dr Tamar Barkay, Rutgers University) were used. Primers targeting Actinobacteria or a-Proteobacteria were tested on mercury-resistant isolates from Oregaard et al (2007).…”

Section: Methodsmentioning

confidence: 99%

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High diversity of bacterial mercuric reductase genes from surface and sub-surface floodplain soil (Oak Ridge, USA)

Øregaard

Sørensen

2007

The ISME Journal

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DNA was extracted from different depth soils (0-5, 45-55 and 90-100 cm below surface) sampled at Lower East Fork Poplar Creek floodplain (LEFPCF), Oak Ridge (TN, USA). The presence of merA genes, encoding the mercuric reductase, the key enzyme in detoxification of mercury in bacteria, was examined by PCR targeting Actinobacteria, Firmicutes or b/c-Proteobacteria. b/c-Proteobacteria merA genes were successfully amplified from all soils, whereas Actinobacteria were amplified only from surface soil. merA clone libraries were constructed and sequenced. b/c-Proteobacteria sequences revealed high diversity in all soils, but limited vertical similarity. Less than 20% of the operational taxonomic units (OTU) (DNA sequences X95% identical) were shared between the different soils. Only one of the 62 OTU was X95% identical to a GenBank sequence, highlighting that cultivated bacteria are not representative of what is found in nature. Fewer merA sequences were obtained from the Actinobacteria, but these were also diverse, and all were different from GenBank sequences. A single clone was most closely related to merA of a-Proteobacteria. An alignment of putative merA genes of genome sequenced mainly marine a-Proteobacteria was used for design of merA primers. PCR amplification of soil a-Proteobacteria isolates and sequencing revealed that they were very different from the genome-sequenced bacteria (only 62%-66% identical at the amino-acid level), although internally similar. In light of the high functional diversity of mercury resistance genes and the limited vertical distribution of shared OTU, we discuss the role of horizontal gene transfer as a mechanism of bacterial adaptation to mercury.

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Section: Resultsmentioning

confidence: 72%

Section: Methodsmentioning

confidence: 99%

High diversity of bacterial mercuric reductase genes from surface and sub-surface floodplain soil (Oak Ridge, USA)

Øregaard

Sørensen

2007

The ISME Journal

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“…The adenosine start point was located three bases downstream of the previously suggested guanosine. In view of this position, the À10 region TAAACT, suggested by Huang et al, 12) including the ideal hexamers, with a 20-bp spacer region of O/P merR2 that coincides with O/P merB3 and O/P merR1 (Fig. 1B), appears to be a better candidate for sigma recognition.…”

Section: Discussionmentioning

confidence: 81%

“…1A). 11,12) The Bacillus gene determinant is complex, with three operator/promoter regions (O/P merB3 , O/P merR1 , and O/P merR2 ) regulated by two MerR regulatory proteins (MerR1 and MerR2), and with three MerB organomercurial lyases of differing substrate specificity.…”

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confidence: 99%

Interactions between Two MerR Regulators and Three Operator/Promoter Regions in the Mercury Resistance Module ofBacillus megaterium

Chen

Hsieh

Silver

et al. 2008

Bioscience, Biotechnology, and Biochemistry

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“…The mer operon is among the most diverse and ubiquitous in bacteria, having been identified in a broad range of species isolated from both environmental and clinical settings. Mer operons have been identified on plasmids (Clark et al 1977;Griffin et al 1987;Summers and Silver 1972), on transposons (Misra et al 1984;Huang et al 1999), and in genomic DNA (Inoue et al 1991;Wang et al 1987). As with resistance to antibiotics and other heavy metals, resistance to Hg can be disseminated through populations of bacteria by natural processes (Bogdanova et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Continuation of Crosscutting Technology Development at Cast

Yoon¹

2012

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5Figure ES-2. Optimization of conditions for leaching Coal B with hydrochloric acid solutions (The selection of time/pH conditions in the dark green region should result in the removal of >30% of the sodium. Note also that a flag has been added to show the amount of sodium in the leach solution, 35% sodium removal, and the sodium content in the product ash). Coal DCoal D showed significantly greater sodium removal than Coal B for similar treatment conditions. The treatability of Coal B is demonstrated in Figures ES3 to ES5. . Coal D leach results for hydrochloric acid solutions (Greater than 75% of the sodium was removed using pH 3 acidic solutions at a 1-hour treatment time. The initial sodium, reported as sodium oxide in the ash, was 6.16 %. The removal of over one-half of the sodium can be achieved using conditions of pH 5, 0.5 hours). Recommended Future StudiesIt is recommended that future studies include, but not be limited to:• Investigation to determine if multiple leach solution contacts with new coal will allow recycle of the leach solution without detrimentally affecting the leachability of the coals and to produce a concentrated sodium bearing solution in order to limit the amount of leach solution that would have to be treated prior to water recycle or disposal.• Water cleanup will be required because of the relatively high sodium and chloride or sulfate content.• Evaluation of where and how the leachate could be introduced into the coal preparation treatment system. • Evaluation of the possible impact of pretreatment on the subsequent shipping and combustion processes.• The anticipated cost of the sodium cleansing treatment and subsequent water treatments. INTRODUCTION BackgroundThe US Department of Energy (DOE) Center for Advanced Separation Technologies (CAST), Great Northern Properties (GN), and the Montana Board Research and Commercialization Technology (MBRCT) are funding this project. The project is being administered and the research directed and conducted at CAMP. The intent of the project is to identify, and validate selected currently used (or previously studied) removal and sodium recovery treatment alternative(s) using laboratory bench-scale tests on four Montana coal samples. If the coals cannot be effectively treated by known techniques, alternative treatments will be developed. The evaluation of selected sodium removal technologies are presently underway and the following four stages are being and will be followed in future work: the successful removal of sodium from the coal so that the ash will content less than three percent, the rate at which the sodium ions are removed, characterization of the waste produced by sodium removal processing, and the overall economics of viable processes. Not part of the initial Project, but a necessary follow-up, will be the scale-up of the most appropriate sodium removal technology(s) in applications with companies using Clean Coal Technology to demonstrate sodium removal process or processes on a pilot scale. Objective and ApproachThe overall ob...

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Identification of three merB genes and characterization of a broad-spectrum mercury resistance module encoded by a class II transposon of Bacillus megaterium strain MB1

Cited by 52 publications

References 21 publications

High diversity of bacterial mercuric reductase genes from surface and sub-surface floodplain soil (Oak Ridge, USA)

High diversity of bacterial mercuric reductase genes from surface and sub-surface floodplain soil (Oak Ridge, USA)

Interactions between Two MerR Regulators and Three Operator/Promoter Regions in the Mercury Resistance Module ofBacillus megaterium

Continuation of Crosscutting Technology Development at Cast

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