• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.331-337
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• 2013

Formate dehydrogenase (FDH), catalyzing the oxidation of the formate ion to carbon dioxide, is known as the stress protein in response to drought, low temperature and pathogen infection. To study the functions of FDH in poplar (Populus alba ${\times}$ P. glandulosa), we isolated a FDH cDNA (PagFDH1) and examined its expressional characteristics. The PagFDH1 is 1,499 base pairs long and encodes a putative 388 amino acid protein with an expected molecular mass of 42.5 kDa. The PagFDH1 protein has N-terminal mitochondria signal peptide and $NAD^+$ binding domain. Southern blot analysis indicated that a single copy of the PagFDH1 is present in the poplar genome. PagFDH1 is expressed highly in the suspension cells (especially in the lag and early exponential phases) and moderately in roots, flowers and leaves. ABA-mediated enhanced expression of PagFDH1 in response to drought and salt stress treatments indicates that the gene product could play an important role in the development of stress resistant trees.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.207-211
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• 1998

Melhylovorus sp. strain SS1 grown on methanol was found to show activities of key enzymes of the linear route, $NAD^+$-linked formaldehyde and formate dehydrogenases, and the cyclic route, hexulose-6-phosphate synthase, glucose-6-phosphate isomerase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase, for formaldehyde oxidation. The activities of the cyclic route enzymes were higher than those of the linear route enzymes. The bacterium also exhibited activities of the key enzymes of the ribulose monophosphate and Entner-Doudoroff pathways and transaldolase involved in the formaldehyde assimilation and the enzymes involved in the biosynthesis of extracellular polysaccharide. Cells grown in the presence of 2.3 mM ammonium sulfate were higher in the productivity of extracellular polysaccharide, but lower in the growth yield, than those grown in the presence 7.6 mM ammonium sulfate. The activities of 6-phosphogluconate dehydrogenase, phosphoglucomutase, and UDP-pyrophosphorylase in cells grown under nitrogen-limited condition were higher, but that of 6-phosphogluconate dehydratase/2-keto-3-deoxy-6-phosphogluconate aldolase was lower, than those in cells grown in the presence of sufficient amount of nitrogen source.

• Proceedings of the Microbiological Society of Korea Conference
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• 1997.04a
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• pp.64.1-64.1
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• 1997

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.753-761
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• 2020

To determine the role of pyruvate dehydrogenase complex (PDHC) in Klebsiella pneumoniae, the growth and metabolism of PDHC-deficient mutant in glycerol-based medium were analyzed and compared with those of other strains. Under aerobic conditions, the PDHC activity was fourfold higher than that of pyruvate formate lyase (PFL), and blocking of PDHC caused severe growth defect and pyruvate accumulation, indicating that the carbon flux through pyruvate to acetyl coenzyme A mainly depended on PDHC. Under anaerobic conditions, although the PDHC activity was only 50% of that of PFL, blocking of PDHC resulted in more growth defect than blocking of PFL. Subsequently, combined with the requirement of CO₂ and intracellular redox status, it was presumed that the critical role of PDHC was to provide NADH for the anaerobic growth of K. pneumoniae. This presumption was confirmed in the PDHC-deficient mutant by further blocking one of the formate dehydrogenases, FdnGHI. Besides, based on our data, it can also be suggested that an improvement in the carbon flux in the PFL-deficient mutant could be an effective strategy to construct high-yielding 1,3-propanediol-producing K. pneumoniae strain.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.598-598
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• 2003

• YAKHAK HOEJI
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• v.47 no.3
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• pp.184-189
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• 2003

Peptide deformylase (PDF) is essential and unique to bacteria, thus making it an attractive target for the discovery of novel antibacterial drugs. PDF deformylates the N-formylmethionine of newly synthesized polypeptides in prokaryotes. In this study, a pdf gene from Staphylococcus aureus 6538p was cloned in pET-14b vector and PDF protein was over-produced in Escherichia coli BL21 (DE3). NH$_2$-terminal His-tagged PDF protein was purified by nickel-nitrilotriacetic acid (Ni-NTA) metal-affinity chromatography. Enzymatic activity of purified 6xHis-tagged PDF was tested on the substrate (formyl-Methionine-Alanine-Serine) by formate dehydrogenase-coupled spectrometric assay of peptide deformylase. For the discovery of new PDF inhibitors from chemical libraries and culture broths of soil bacteria, a target-oriented screening system using a 96-well plate was developed. About 3,000 commercial chemical libraries were tested in this screening system, and 2 chemicals (0.07％) among them showed an inhibitory activity against PDF enzyme. This result showed that a new screening system can be used for the discovery of new PDF inhibitors.

• Korean Journal of Microbiology
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• v.20 no.4
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• pp.161-172
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• 1982

In order to compare the metabolic activities of methanol utilizing bacteria, Pseudomonas sp. grown in different carbon sources, changes in respiratory activities, prinicipal enzyme activities for the energy metabolism, and the macromolecular compositions of the cells grown on methanol or glucose were measured. 1. The respiratory activity of cells grown on methanol was higher than that of cells grown on glucose, while glucose exhibited the highest $O_2-consumption$ rate among the different respiratory substrates. 2. TRhe activity of hydroxy pyruvate reductase which participates in serine pathway was high in the cells grown on methanol. However, activities of NAD-linked alcohol dehydrogenase, formaldehyde dehydrogenase and formate dehydrogenase were slightly lower in the cells grown on glucose thant on methanol. 4. For succinic dehydrogenase and malic dehydrogenase which take part in TCA cycle, the specific activities were higher in the cells grown on methanol than in those grown on glucose. No activity of glucose-6-phosphate dehydrogenase, which participates in pentose monophosphate shunt, was detectable in the cells grown on either carbon sources. 5. Protein contents of the cells grown on methanol increased relatively compared with those of the cells grown on glucose. However, there are no changes in the contents of carbohydrate and nucleic acid.

• Journal of Microbiology
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• v.35 no.1
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• pp.30-39
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• 1997

Acinetobacter sp. strain JC1 DSM 3803, a carboxydobacterium, was found to grow methylotrophically at the expense of methanol and methlamine, but not of methane, formaldehyde, formate, dimethylamine, or trimethylamine, as the sole source of carbon and energy. The doubling times of the bacterium growing on methanol (0.5%, v/v) and methylamine (0.5%, w/v) at 3$0^{\circ}C$ and pH 6.8 were 4.8 h and 5.7 h, respectively. Cells grown on methanol, however, failed to show typical methanol dehydrogenase and oxidase activities. The cell was found to contain no c-type cytochromes. Cells grown on methanol exhibited higher catalase activity than those grown on pyruvate or glucose. The catalase present in the cells also exhibited peroxidase activity. The catalase activity, growth on methanol of the cell, and oxygen consumption by methanol-grown maldehyde dehydrogenase, formaldehyde reductase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase activities were detected from cells grown on methanol.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.375-380
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• 2015

Recently, methane has attracted much attention as an alternative carbon feedstock since it is the major component of abundant shale and natural gas. In this work, we produced methanol from methane using whole cells of Methylosinus trichosporium OB3b as the biocatalyst. M. trichosporium OB3b was cultured on NMS medium with a supply of 7:3 air/methane ratio at 30℃. The optimal concentrations of various methanol dehydrogenase inhibitors such as potassium phosphate and EDTA were determined to be 100 and 0.5 mM, respectively, for an efficient production of methanol. Sodium formate (40 mM) as a reducing power source was added to enhance the conversion efficiency. A productivity of 49.0 mg/l·h, titer of 0.393 g methanol/l, and conversion of 73.8% (mol methanol/mol methane) were obtained under the optimized batch condition.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.717-724
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• 2016

Methane (CH₄) is the most abundant component in natural gas. To reduce its harmful environmental effect as a greenhouse gas, CH₄ can be utilized as a low-cost feed for the synthesis of methanol by methanotrophs. In this study, several methanotrophs were examined for their ability to produce methanol from CH₄; including Methylocella silvestris, Methylocystis bryophila, Methyloferula stellata, and Methylomonas methanica. Among these methanotrophs, M. bryophila exhibited the highest methanol production. The optimum process parameters aided in significant enhancement of methanol production up to 4.63 mM. Maximum methanol production was observed at pH 6.8, 30℃, 175 rpm, 100 mM phosphate buffer, 50 mM MgCl₂ as a methanol dehydrogenase inhibitor, 50% CH₄ concentration, 24 h of incubation, and 9 mg of dry cell mass ml^-1 inoculum load, respectively. Optimization of the process parameters, screening of methanol dehydrogenase inhibitors, and supplementation with formate resulted in significant improvements in methanol production using M. bryophila. This report suggests, for the first time, the potential of using M. bryophila for industrial methanol production from CH₄.