Abstract:
:A colorimetric assay for NADPH-dependent, mercuric ion-specific oxidoreductase activity was developed to facilitate the investigation of mercuric reductase gene expression in polluted aquatic ecosystems. Protein molecules extracted directly from unseeded freshwater and samples seeded with Pseudomonas aeruginosa PU21 (Rip64) were quantitatively assayed for mercuric reductase activity in microtiter plates by stoichiometric coupling of mercuric ion reduction to a colorimetric redox chain through NADPH oxidation. Residual NADPH was determined by titration with phenazine methosulfate-catalyzed reduction of methyl thiazolyl tetrazolium to produce visible formazan. Spectrophotometric determination of formazan concentration showed a positive correlation with the amount of NADPH remaining in the reaction mixture (r2 = 0.99). Mercuric reductase activity in the protein extracts was inversely related to the amount of NADPH remaining and to the amount of formazan produced. A qualitative nitrocellulose membrane-based version of the method was also developed, where regions of mercuric reductase activity remained colorless against a stained-membrane background. The assay detected induced mercuric reductase activity from 10(2) CFU, and up to threefold signal intensity was detected in seeded freshwater samples amended with mercury compared to that in mercury-free samples. The efficiency of extraction of bacterial proteins from the freshwater samples was (97 +/- 2)% over the range of population densities investigated (10(2) to 10(8) CFU/ml). The method was validated by detection of enzyme activity in protein extracts of water samples from a polluted site harboring naturally occurring mercury-resistant bacteria. The new method is proposed as a supplement to the repertoire of molecular techniques available for assessing specific gene expression in heterogeneous microbial communities impacted by mercury pollution.
journal_name
Appl Environ Microbioljournal_title
Applied and environmental microbiologyauthors
Ogunseitan OAdoi
10.1128/AEM.64.2.695-702.1998subject
Has Abstractpub_date
1998-02-01 00:00:00pages
695-702issue
2eissn
0099-2240issn
1098-5336journal_volume
64pub_type
杂志文章abstract::We describe the development and validation of a method for the qualitative analysis of complex bifidobacterial communities based on PCR and denaturing gradient gel electrophoresis (DGGE). Bifidobacterium genus-specific primers were used to amplify an approximately 520-bp fragment from the 16S ribosomal DNA (rDNA), and...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.67.2.504-513.2001
更新日期:2001-02-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.54.6.1541-1549.1988
更新日期:1988-06-01 00:00:00
abstract::Bacillus cereus endospores germinate in response to particular nutrients. Spores are able to sense these nutrients in the environment by receptors encoded by the gerA family of operons. Analysis of the Bacillus cereus ATCC 14579 genome revealed seven gerA family homologues. Using a transposon Tn917-based insertional m...
journal_title:Applied and environmental microbiology
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doi:10.1128/AEM.71.2.774-781.2005
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.62.7.2534-2539.1996
更新日期:1996-07-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.63.8.3233-3241.1997
更新日期:1997-08-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.49.4.882-886.1985
更新日期:1985-04-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.46.5.1234-1235.1983
更新日期:1983-11-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:2018-03-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.44.6.1476-1478.1982
更新日期:1982-12-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.02800-07
更新日期:2008-05-01 00:00:00
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pub_type: 杂志文章
doi:10.1128/AEM.55.8.1901-1906.1989
更新日期:1989-08-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.60.1.111-119.1994
更新日期:1994-01-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.00251-09
更新日期:2009-07-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.56.7.2251-2254.1990
更新日期:1990-07-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.32.4.592-597.1976
更新日期:1976-10-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.49.3.693-701.1985
更新日期:1985-03-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.47.4.735-739.1984
更新日期:1984-04-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
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更新日期:2001-11-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/aem.68.3.1211-1219.2002
更新日期:2002-03-01 00:00:00
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journal_title:Applied and environmental microbiology
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doi:10.1128/AEM.49.2.289-293.1985
更新日期:1985-02-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01336-19
更新日期:2019-10-16 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.58.1.431-433.1992
更新日期:1992-01-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.06524-11
更新日期:2011-12-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.63.10.3866-3871.1997
更新日期:1997-10-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.57.12.3489-3495.1991
更新日期:1991-12-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.37.3.596-600.1979
更新日期:1979-03-01 00:00:00
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journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.62.5.1583-1588.1996
更新日期:1996-05-01 00:00:00
abstract::Trichoderma species isolated from water-damaged buildings were screened for toxicity by using boar sperm cells as indicator cells. The crude methanolic cell extract from Trichoderma harzianum strain ES39 inhibited the boar sperm cell motility at a low exposure concentration (50% effective concentration, 1 to 5 microg ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.70.8.4996-5004.2004
更新日期:2004-08-01 00:00:00
abstract::Malic acid has great potential for replacing petrochemical building blocks in the future. For this application, high yields, rates, and titers are essential in order to sustain a viable biotechnological production process. Natural high-capacity malic acid producers like the malic acid producer Aspergillus flavus have ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.01445-13
更新日期:2013-10-01 00:00:00
abstract::"Caldocellum saccharolyticum" is an obligatory anaerobic thermophilic bacterium. A gene from this organism, designated celB, has been cloned in Escherichia coli as part of a bacteriophage lambda gene library. This gene produces a thermostable cellulase that shows both endoglucanase and exoglucanase activities on test ...
journal_title:Applied and environmental microbiology
pub_type: 杂志文章
doi:10.1128/AEM.56.10.3117-3124.1990
更新日期:1990-10-01 00:00:00