• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.627-636
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• 2016

The causative agent of pandemic cholera, Vibrio cholerae, infects the anaerobic environment of the human intestine. Production of cholera toxin (CT), a major virulence factor of V. cholerae, is highly induced during anaerobic respiration with trimethylamine N-oxide (TMAO) as an alternative electron acceptor. However, the molecular mechanism of TMAO-stimulated CT production is not fully understood. Herein, we reveal that CT production during anaerobic TMAO respiration is affected by glucose fermentation. When the seventh pandemic V. cholerae O1 strain N16961 was grown with TMAO and additional glucose, CT production was markedly reduced. Furthermore, an N16961 Δcrp mutant, devoid of cyclic AMP receptor protein (CRP), was defective in CT production during growth by anaerobic TMAO respiration, further suggesting a role of glucose metabolism in regulating TMAO-mediated CT production. TMAO reductase activity was noticeably decreased when grown together with glucose or by mutation of the crp gene. A CRP binding region was identified in the promoter region of the torD gene, which encodes a structural subunit of the TMAO reductase. Gel shift assays further confirmed the binding of purified CRP to the torD promoter sequence. Together, our results suggest that the bacterial ability to respire using TMAO is controlled by CRP, whose activity is dependent on glucose availability. Our results reveal a novel mechanism for the regulation of major virulence factor production by V. cholerae under anaerobic growth conditions.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.218-225
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• 2007

A lactic acid bacterium capable of anaerobic respiration was isolated from soil with ferric iron-containing glucose basal medium and identified as L. garvieae by using 16S rDNA sequence homology. The isolate reduced ferric iron, nitrate, and fumarate to ferrous iron, nitrite, and succinate, respectively, under anaerobic $N_2$ atmosphere. Growth of the isolate was increased about 30-39% in glucose basal medium containing nitrate and fumarate, but not in the medium containing ferric iron. Specifically, metabolic reduction of nitrate and fumarate is thought to be controlled by the specific genes fnr, encoding FNR-like protein, and nir, regulating fumarate-nitrate reductase. Reduction activity of ferric iron by the isolate was estimated physiologically, enzymologically, and electrochemically. The results obtained led us to propose that the isolate metabolized nitrate and fumarate as an electron acceptor and has specific enzymes capable of reducing ferric iron in coupling with anaerobic respiration.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.15-18
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• 1998

The entanol productivity of superoxide dismutase (SOD)-deficient mutants of Saccharo-Myces cerevisiae was examined under the oxidative stress by Paraquat. It was observed that MnSOD-deficient mutant of S. cerevisiae had higher ethanol productivity than wild type or CuZnSOD-deficient yeast both in aerobic and in anaerobic culture condition. Pyruvated dehydrogenase activity decreased by 35% and alcohol dehydrogenase activity increased by 32% were observed in MnSOD-deficient yeast grown aerobically. When generating oxygen radicals by Paraquat, the ehanol productivity was increased by 40% in CuZnSOD-deficient or wild strain, resulting from increased activity of alcohol dehydrogenase and decreased a activity of pyruvate dehydrogenase. However, the addition of ascorbic acid with Paraquat returned the enzyme activities at the level of control. These results imply that SOD-deficiency in yeast strains may cause the metabolic flux to shift into anaerobic ethanol fermentation in order to avoid their oxidative damages by Paraquat.

• Korean Journal of Microbiology
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• v.6 no.2
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• pp.41-53
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• 1968

Studies on the carbohydrate metabolism of yeast as influenced by gamma-irradiation from cobalt-60 have been carried, then the mechanisms of radiation effect on respiration and fermentation were discussed under considerations of permeable changes of irradiated cell membrane. The cells of baker's yeast (Saccharomyces cerevisiae) which had been gamma-irradiated of 240 k.r. doses for an hour, then were put into aerobic oxidation and anaerobic fermentation without substrate. Total and fractionated carbohydrates of irradiated yeast cells were determined by calorimetric method with anthrone and orcinol reagents, the amounts of total carbohydrate, trehalose, RNA-ribose, PCA-soluble glycogen, alkali-soluble glycogen, acetic acid-soluble glycogen, mannan and glucan were determined according to the course of aerobic oxidation and anaerobic fermentation. It is found that the carbohydrates of irradiated cells leak out and amount of the losses teaches eleven times more than that of control, the volume of losses are seems to be replaced by water, it can be suggested the damage of gamma-irradiation occurs in the site of passive transport of cell membrane. The endogeneous aerobic respiration of irradiated cells are increased much more than control, the synthesis of reserve glycogen, glucan and RNA-ribose promoted much more than control. The anaerobic fermentation of irradiated cells are also increased than that of control, but the breakdown of carbohydrate is less than endogeneous respiration of irradiated cells. The synthetic rate is also less than that of aerobic oxidation. In irradiated yeast cells, trehalose is revealed to be primary substrate for endogeneous carbohydrate metabolism, so it is proved that the enzymic patterns are not changed but the activities of enzymes relating endogeneous respiration and autofermentation is activated. It is to be considerable to distiguish endogeneous respiration and autofermentation from exogeneous respiration and fermentation on irradiation, for membrane permeability changes and loses out carbohydrate by ionizing radiation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.260-265
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• 2012

Soil respiration under flooded conditions is considered to be very small compared with aerobic soil respiration of soil organic matter. However, anaerobic decomposition of soil plays a key role in carbon cycling in flooded ecosystems. On the other hand, coal-ash wastes, such as fly ash and bottom ash, are known to function as a soil amendment for mitigating $CO_2$ emission and enhancing carbon sequestration in up land soils. In this study, we investigated bottom ash as a soil amendment for mitigating $CO_2$ emission, and thus enhancing carbon sequestration under anaerobic conditions. We observed that amendment of bottom ash without external organic source led to significant reduction in $CO_2$ emission rate and in total cumulative $CO_2$ emission flux over the incubation period, which was proportional to the amount of bottom ash applied. We also found that soil microbial biomass increased in response to application of bottom ash. These results suggest that bottom ash can be utilized to store $CO_2$ as a stable soil organic carbon in flooded ecosystems, as in aerobic situations.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.252-259
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• 1999

Anoxic sediments collected from Shiwha-ho area were used to find the relationship between the heavy-metal, organic content and anaerobic respiration bacteria by most probable number (MPN) method. Analysis of the sediments showed that COD content was higher in the sediments collected from Ansan-cheon and Shiwha-ho than those collected from sea area nearby. Particularly noticeable was the fact that heavy metal concentration was much higher in the sediments of Shiwha-ho area contaminated by heavy-metal, although they were rich in electron donor and electron acceptor for Fe(III)-reducing bacteria using lactate as an electron donor was in the range of 1.1$\times$106-4.6$\times$107MPNs/ml in the sediments collected from the sea-side of the lake, which were lower in heavy-methal concentration and higher in Fe-Mn content than those from other region. The number of Fe(III)-reducing bacteria using acetate as an electron donor was in the rang eof 4.3$\times$102-8.1$\times$105MPNs/ml in the same sediments. Chromate-reducing bacteria were more populated(4.6$\times$104-8.1$\times$105MPNs/ml) in the sediments contaminated by heavy metals. The number of sulfate-reducing bacteria wee counted in the sediments collected from the more contaminate inner-side than those from the sea-side of the lake.

• Clean Technology
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• v.8 no.2
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• pp.77-83
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• 2002

The purpose of this study is to develop the efficient nutrient removal process and to verify operation and design parameters in domestic sewage. Endogenous nitrate respiration (ENR) was used for denitrification of nitrate in return sludge without additional organic carbon source. ENR reactor before the anaerobic tank enable to reduce nitrate below 3 mg/L and increase phosphate release at anaerobic reaction. Primary effluent during pilot scale plant were shown as TCOD/TP ratio of 40~60 and TCOD/TKN ratio of 5~7. Effluent concentrations were 10 to 12mg/L as TN and 1mg/L as TP respectively. In lab scale experiments endogenous denitrification rate of ENR reactor ranges from 0.042 to $0.057gNO_3-N/gMv.d.$ $SP_{rel}/SCOD_{rm}$ was shown as from 0.13 to 0.17 in anaerobic reaction. These kinetic parameters are expected to be available for BNR(Biological Nutrient Removal) plant design and ENR reaction is available for nutrient removal in low strength wastewater.

• BMB Reports
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• v.29 no.1
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• pp.88-91
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• 1996

The anaerobically expressed gene aeg-46.5, which had been identified by the operon fusion technique with a hybrid bacteriophage of ${\lambda}$ and Mu, ${\lambda}$placMu53, was studied for its expression pattern and growth. The expression of aeg-46.5 was studied in the wild-type cell and mutant cells that have mutation (s) in the control gene of anaerobic respiration (fnr) and nitrate response (narL and narP). The ${\beta}$-galactosidase reporter gene showed maximum expression in narL host after two hours of aerobic to anaerobic switch in M9-Glc-nitrate medium. Both 40 mM and 100 mM concentrations of nitrate ion in the medium had little effect on expression level. We propose that aeg-46.5 is subject to multiple regulations of anaerobic activation by Fnr, nitrate activation by NarP and repression mediated by NarL.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.104-109
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• 2004

In this study, we stabilized the screened soil from landfills by using aerobic bioreactor and evaluated aerobic decomposition of it. Four lab-scale bioreactors (anaerobic and 1 PV/day aeration, 5 PV/day aeration, 10 PV/day aeration) filled with screened soil were operated to investigate the effect of air injection quantity on stabilization of screened soil. In case of aerobic bioreactors, the decomposition of organics in screened soil was higher than anaerobic bioreactor. According to the results of landfill gas and soil respiration test, the air injection quantity of 5 PV/day was most efficient in stabilization of screened soil.

• The Korean Journal of Zoology
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• v.4 no.1
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• pp.7-12
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• 1961

1) Respiratory metabolism patterns and its enzyme systems in the gill tissue of the fresh water mussels, Cristaria plicata were investigated through the examination on the effects of respiratory enzyme inhibitors, (KCN, NAF) and succinoxidase assay, while studying the effects of neutral salts (NaCL, KCL, CaCl2) and pH on oxygen consumption of the gill tissue. 2) In the limited concentration of KCL (0.3mM) and NaCl (0.4mM) solutions, oxygen consumption of the intact gill tissue was accelerated, but in CaCl2(0.5mM) solution, it showed no significant effect. The oxygen consumption was gradually decreased at the above concentrations of these limitations. The optimum pH for the respiration of the gill was 7.3. 3)Cyanide in 10-8M solution inhibited 88.8% of the respiration of the intact gill tissue. Methylene blue accelerated the respiration of the noral gill tissue, and slightly but significantly reversed the cyaniide poisoned respiration. 4)Oxygen consumption of the gill homogenate was apparently increased by the mixed addition of succinate, cytochrome c and activators (AlCl3 and CaCl2). This results suggested that succinoxidase system acts on the respiratory pattern of the gil tissue. 5) It was able to recognize that the enolase, which acts on the anaerobic glycolytic system, participated in the tissue respiration of the gill for NaF in 5$\times$10-2 M solution inhibited 55.5% of the respiration of the same intact tissue.