Phenotypic characterization of copper-resistant mutants of Methylosinus trichosporium OB3b

Fitch, Mark W.; Graham, David W.; Arnold, Robert G.; Agarwal, SK; Phelps, P.; Speitel, Gerald E.; Georgiou, George

doi:10.1128/aem.59.9.2771-2776.1993

Cited by 80 publications

(57 citation statements)

References 28 publications

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“…Methanotrophs clearly respond to copper, and as such, these microbes must have some mechanism to sense and collect copper from the environment. Initial evidence for such machinery came from the characterization of constitutive sMMO mutants (sMMO C ) of Methylosinus trichosporium OB3b constructed using random chemical mutagenesis (56,57). These mutants had impaired copper uptake compared to the M. trichosporium OB3b wild type, suggesting that methanotrophs can synthesize a copper-complexing agent, or chalkophore ("chalko" is Greek for "copper").…”

mentioning

confidence: 99%

Metals and Methanotrophy

Semrau

DiSpirito

et al. 2018

Appl Environ Microbiol

121

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Aerobic methanotrophs have long been known to play a critical role in the global carbon cycle, being capable of converting methane to biomass and carbon dioxide. Interestingly, these microbes exhibit great sensitivity to copper and rare-earth elements, with the expression of key genes involved in the central pathway of methane oxidation controlled by the availability of these metals. That is, these microbes have a "copper switch" that controls the expression of alternative methane monooxygenases and a "rare-earth element switch" that controls the expression of alternative methanol dehydrogenases. Further, it has been recently shown that some methanotrophs can detoxify inorganic mercury and demethylate methylmercury; this finding is remarkable, as the canonical organomercurial lyase does not exist in these methanotrophs, indicating that a novel mechanism is involved in methylmercury demethylation. Here, we review recent findings on methanotrophic interactions with metals, with a particular focus on these metal switches and the mechanisms used by methanotrophs to bind and sequester metals.

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mentioning

confidence: 99%

Metals and Methanotrophy

Semrau

DiSpirito

et al. 2018

Appl Environ Microbiol

121

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“…This limits the speed with which sMMOcontaining biomass can be generated. In addition, transcription of the smnino locus is repressed by low concentrations of copper ions (0.25 ,uM) (47); hence, sMMO may not be expressed in the natural environment, and it will be difficult to use M. trichosporilum OB3b for in situ bioremediation (6,12,39). Furthermore, sMMO is competitively inhibited by the substrates methane and TCE (35).…”

mentioning

confidence: 99%

Trichloroethylene and chloroform degradation by a recombinant pseudomonad expressing soluble methane monooxygenase from Methylosinus trichosporium OB3b

Jahng

Wood

1994

Appl Environ Microbiol

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Soluble methane monooxygenase (sMMO) from Methylosinus trichosporium OB3b can degrade many halogenated aliphatic compounds that are found in contaminated soil and groundwater. This enzyme oxidizes the most frequently detected pollutant, trichloroethylene (TCE), at least 50 times faster than other enzymes. However, slow growth of the strain, strong competition between TCE and methane for sMMO, and repression of the smmo locus by low concentrations of copper ions limit the use of this bacterium. To overcome these obstacles, the 5.5-kb smmo locus of M. trichosporium OB3b was cloned into a wide-host-range vector (to form pSMMO20), and this plasmid was electroporated into five Pseudomonas strains. The best TCE degradation results were obtained with Pseudomonas putida F1/pSMMO20. The plasmid was maintained stably, and all five of the sMMO proteins (a, ,(, and-y hydroxylase proteins, reductase, and component B) were observed clearly by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblotting. TCE degradation rates were quantified for P. putida F1/pSMMO20 with a gas chromatograph (Vmax = 5 nmol per min per mg of protein), and the recombinant strain mineralized 55% of the TCE (10 ,uM) as indicated by measuring chloride ion concentrations with a chloride ion-specific electrode. The maximum TCE degradation rate obtained with the recombinant strain was lower than that of M. trichosporium OB3b but greater than other TCE-degrading recombinants and most well-studied pseudomonads. In addition, this recombinant strain mineralizes chloroform (a specific substrate for sMMO), grows much faster than M. trichosporium OB3b, and degrades TCE without competitive inhibition from the growth substrate. MATERIALS AND METHODS Plasmids, bacterial strains, and routine culture conditions. Plasmids pDVC202 (orJY' mmoC+) and pDVC210 (mmoX+ Y+B+Z+) (7, 8) were kindly provided by J. C. Murrell at the University of Warwick, Coventry, United Kingdom, and the wide-host-range plasmid pMMB277 (31) was obtained from M. Bagdasarian at Michigan State University. E. coli XL1-Blue {recAl endAl gyrA96 thi-I hsdRl7 supE44 relAl lac [F' proAB lacIVAM15 TnJO (Tetr)I} was used for cloning in E. coli, was purchased from Stratagene, La Jolla, Calif., and was cultivated in LB (40) containing 10 pug of tetracycline per ml. M. trichosporium OB3b was obtained from R. S. Hanson at the Gray Freshwater Institute, University of Minnesota. This methanotroph was cultivated in HNMS (Higgins nitrate minimal salt) medium without copper sulfate, and methane gas (Liquid Carbonic, Chicago, Ill.) was supplied twice a day as described by Park et al. (38). P. putida KT2440 (4) (r-m+) was obtained from M. Bagdasarian and was grown in LB medium. P. cepacia G4 (13) and P. cepacia G4 PR1 (45) were provided by M. S. Shields at the University of West Florida and were grown in LB alone and LB with 25 ,ug of kanamycin per ml, respectively. P. mendocina KR1 (54) was obtained from K.-M. Yen at Amgen Inc., Thousand Oaks, Calif., P. putida Fl (51) was provided by ...

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“…While the crystal structure of Methylococcus can be found on this subject (Cooksey, 1993;Reusing and Grass, 2003;Lu et al, 2003;Harrison et al, 2000;Nies, 1999;Vulpe and Packman, 1995;Puig et al, 2002); therefore, no further details will be discussed in this literature review. In contrast to most other microorganisms, copper plays a very important role in methanotroph physiology; however, it is believed they are not typically starved for copper in the environment (Berson and Lidstrom, 1996;Fitch et al, 1993). Despite this, it has been suggested by numerous researchers that these organisms may possess a specific copper-trafficking system due to their high copper dependencies.…”

Section: Methanotrophic Bacteriamentioning

confidence: 99%

“…To better understand the physiological role and ecological significance of copper regulation in methanotrophic M. trichosporium OB3b, Fitch et al (1993) used five previously isolated mutants (Phelps, et al, 1992) that exhibited constitutive sMMO activity in the presence of copper; an activity that would normally be repressed in wild-types. It was suggested that the lack of effects on growth rate and sMMO expression due to copper in these mutants was not a result of increased stability of sMMO to copper deactivation.…”

Section: Chronological Characterization Of Methanobactinmentioning

confidence: 99%

Methanobactin: a potential novel biopreservative for use against the foodborne pathogen Listeria monocytogenes

Johnson

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Phenotypic characterization of copper-resistant mutants of Methylosinus trichosporium OB3b

Cited by 80 publications

References 28 publications

Metals and Methanotrophy

Metals and Methanotrophy

Trichloroethylene and chloroform degradation by a recombinant pseudomonad expressing soluble methane monooxygenase from Methylosinus trichosporium OB3b

Methanobactin: a potential novel biopreservative for use against the foodborne pathogen Listeria monocytogenes

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