Multiple enzymic lesions in obligate methanotrophic bacteria

Shishkina, Valentina N.; Trotsenko, Yu. A.

doi:10.1111/j.1574-6968.1982.tb08264.x

Cited by 40 publications

(20 citation statements)

References 21 publications

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“…However, the functional role of this metabolic pathway in methanotrophs is not fully understood. It has been suggested that the main role of the TCA cycle in the methanotrophs is carbon assimilation rather than energy production, due to low enzyme activity and lack of pyruvate dehydrogenase (Trotsenko, 1976; Anthony, 1982; Shishkina and Trotsenko, 1982; Trotsenko and Murrell, 2008). However, labeling studies on acetate and pyruvate utilization have predicted the presence of a catabolic TCA cycle in type II methanotrophs (Wadzink and Ribbons, 1975; reviewed in Higgins et al, 1981).…”

Section: Resultsmentioning

confidence: 99%

“…However, data on carboxylation system(s) in M. trichosporium OB3b are controversial. Most previous enzymatic studies predict that the PEP carboxylase (Ppc), a key enzyme of the serine cycle, is the major entry point for CO 2 in alphaproteobacterial methanotrophs (Shishkina and Trotsenko, 1982). On the other hand Naguib (1979) has shown that M. trichosporium OB3b possesses different carboxylation systems, including membrane bound and cytoplasmic enzymes.…”

Section: Resultsmentioning

confidence: 99%

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Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part I: Transcriptomic Study

Matsen¹,

Yang²,

Stein³

et al. 2013

Front. Microbiol.

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Methane utilizing bacteria (methanotrophs) are important in both environmental and biotechnological applications, due to their ability to convert methane to multicarbon compounds. However, systems-level studies of methane metabolism have not been carried out in methanotrophs. In this work we have integrated genomic and transcriptomic information to provide an overview of central metabolic pathways for methane utilization in Methylosinus trichosporium OB3b, a model alphaproteobacterial methanotroph. Particulate methane monooxygenase, PQQ-dependent methanol dehydrogenase, the H4MPT-pathway, and NAD-dependent formate dehydrogenase are involved in methane oxidation to CO2. All genes essential for operation of the serine cycle, the ethylmalonyl-CoA (EMC) pathway, and the citric acid (TCA) cycle were expressed. PEP-pyruvate-oxaloacetate interconversions may have a function in regulation and balancing carbon between the serine cycle and the EMC pathway. A set of transaminases may contribute to carbon partitioning between the pathways. Metabolic pathways for acquisition and/or assimilation of nitrogen and iron are discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part I: Transcriptomic Study

Matsen¹,

Yang²,

Stein³

et al. 2013

Front. Microbiol.

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“…There are some metabolic features of methanotrophs that could be the reason for cyclization of glutamate to form 5-oxoproline. Obligate methanotrophs are very sensitive to low-molecular-weight compounds, and their growth is strongly inhibited by amino acids (Eroshin et al 1968;Eccleston and Kelly 1972;Shishkina and Trotsenko 1982). Therefore, the cytoplasmic pool of glutamate in M. alcaliphilus 20Z cells is low (less than 80 mM).…”

Section: Discussionmentioning

confidence: 97%

Osmoadaptation in halophilic and alkaliphilic methanotrophs

Khmelenina

Kalyuzhnaya

Sakharovsky

et al. 1999

Archives of Microbiology

149

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By using (1)H- and (13)C-NMR spectroscopy, an accumulation of sucrose and two cyclic amino acids [ectoine (1,4,5, 6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) and 5-oxoproline (pyrrolidone carboxylic acid)] was detected in the halotolerant methanotrophs Methylobacter alcaliphilus 20Z and Methylobacter modestohalophilus 10S. The organic solute pool was found to increase upon raising the NaCl concentration. In M. alcaliphilus 20Z, the intracellular level of the total solutes was shown to be sufficient to balance the osmotic pressure of the medium, whereas in M. modestohalophilus 10S their content was several times lower. Additionally, phosphatidylglycerol and phosphatidylcholine were predominant cell phospholipids in salt-adapted M. alcaliphilus 20Z. However, no phosphatidylcholine was found in M. modestohalophilus 10S, and the portion of phosphatidylglycerol increased while phosphatidylethanolamine decreased upon elevated external NaCl concentrations. Regularly arranged glycoprotein surface layers (S-layers) of hexagonal and linear (p2) symmetry were observed on the outer cell walls of M. alcaliphilus 20Z and M. modestohalophilus 10S. The S-layer in M alcaliphilus 20Z consisting of tightly packed, cup-shaped subunits was lost during growth at pH 7.2 (the lowest possible pH) in the absence of NaCl. Hence, osmoadaptation in the methanotrophs studied involves structure/function alterations of cell envelopes and changes in the chemical composition of membranes as well as de novo synthesis of compatible solutes.

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“…Methylosinus trichosporium OB3b was first described by Whittenbury et al (1970) and has served as a model system for the investigation of methane utilization in obligate alphaproteobacterial methanotrophs for decades (Lawrence and Quayle, 1970; Strom et al, 1974; Cornish et al, 1984; Jollie and Lipscomb, 1991; Park et al, 1991, 1992; DiSpirito et al, 1998; Lontoh and Semrau, 1998; Gilbert et al, 2000; Trotsenko and Murrell, 2008). While the key metabolic pathways for carbon assimilation in M. trichosporium OB3b have been predicted (Strom et al, 1974), several fundamental questions have never been answered, such as how cells regenerate glyoxylate (Anthony, 1982), what is the role of the TCA cycle in methanotrophic metabolism is (Patel et al, 1979; Shishkina and Trotsenko, 1982), and why CO 2 supplementation has a significant positive effect on cell growth (Park et al, 1991, 1992). A draft genome of M. trichosporium OB3b has recently been generated (Stein et al, 2010), providing a genetic framework for characterization of the methanotrophy.…”

Section: Introductionmentioning

confidence: 99%

Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part II. Metabolomics and 13C-Labeling Study

Yang¹,

Matsen²,

Konopka³

et al. 2013

Front. Microbiol.

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In this work we use metabolomics and 13C-labeling data to refine central metabolic pathways for methane utilization in Methylosinus trichosporium OB3b, a model alphaproteobacterial methanotrophic bacterium. We demonstrate here that similar to non-methane utilizing methylotrophic alphaproteobacteria the core metabolism of the microbe is represented by several tightly connected metabolic cycles, such as the serine pathway, the ethylmalonyl-CoA (EMC) pathway, and the citric acid (TCA) cycle. Both in silico estimations and stable isotope labeling experiments combined with single cell (NanoSIMS) and bulk biomass analyses indicate that a significantly larger portion of the cell carbon (over 60%) is derived from CO2 in this methanotroph. Our13 C-labeling studies revealed an unusual topology of the assimilatory network in which phosph(enol) pyruvate/pyruvate interconversions are key metabolic switches. A set of additional pathways for carbon fixation are identified and discussed.

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Multiple enzymic lesions in obligate methanotrophic bacteria

Cited by 40 publications

References 21 publications

Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part I: Transcriptomic Study

Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part I: Transcriptomic Study

Osmoadaptation in halophilic and alkaliphilic methanotrophs

Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part II. Metabolomics and 13C-Labeling Study

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