• Asian-Australasian Journal of Animal Sciences
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• v.9 no.5
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• pp.557-562
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• 1996

The effects of diets differing in protein content through soybean meal supplementation on ruminal fractionation of selenium (Se) were studied. A $3{\times}3$ Latin square design was used with three Japanese Corriedale wethers (45 kg average body weight), three periods, and three dietary treatment. The three dietary treatments were : Diet 1, without soybean meal supplementation (14% crude protein, CP); Diet 2, with 10% soybean meal supplementation (16.5% CP); and Diet 3, with 20% soybean meal supplementation (19% CP). All the diets had a Se supplementation in the form of sodium selenite at 0.2 mg Se/kg dietary DM. The Se supplement and the concentrate mixture were fed only in the morning before the hay was given. Daily feeding schedule for gay was set at 09:00 and 17:00 h. On the final day of collection period, ruminal fluid samples were obtained at 0.5, 2, 6, 12 and 24 h post-feeding starting at 09:00 h. Total ruminal fluid Se was markedly higher (p<0.05) in Diet 3 than those in Diets 1 and 2 at almost all sampling time except at 24 h. The proportion of Se in soluble protein to the total ruminal Se was higher (p< 0.05) in Diet 3 (40%) followed by Diet 2 (28%) and Diet 1 (21%). The proportion of free inorganic Se to the total ruminal Se was the reverse, especially after two hours where Diet 1 (p<0.05) was higher than the other diets. Bacterial Se was lower (p < 0.05) in Diet 1 than those in Diets 2 and 3 at any sampling time. The highest was observed at 2 h postprandially in all diets with a value of 421, 556, $655{\mu}g/kg$ bacterial DM for Diet 1, 2 and 3, respectively. No differences (p>0.05) were observed on ruminal pH, ammonia and total nolatile fatty acids although increasing protein supplementation tended to decline the ruminal pH and increase ruminal ammonia. This study concludes that increasing dietary protein content by soybean meal supplementation can affect the ruminal Se metabolism.

• BMB Reports
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• v.40 no.5
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• pp.708-714
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• 2007

The two-component signal transduction, which typically consists of a histidine kinase and a response regulator, is used by bacterial cells to sense changes in their environment. Previously, the SphS-SphR histidine kinase and response regulator pair of phosphate sensing signal transduction has been identified in Synechocystis sp. PCC 6803. In addition, some response regulators in bacteria have been shown to be cross regulated by low molecular weight phosphorylated compounds in the absence of the cognate histidine kinase. The ability of an endogenous acetyl phosphate to phosphorylate the response regulator, SphR in the absence of the cognate histidine kinase, SphS was therefore tested in Synechocystis sp. PCC 6803. The mutant lacking functional SphS and acetate kinase showed no detectable alkaline phosphatase activity under phosphate-limiting growth conditions. The results suggested that the endogenous acetyl phosphate accumulated inside the mutants could not activate the SphR via phosphorylation. On the other hand, exogenous acetyl phosphate could allow the mutant lacking functional acetate kinase and phosphotransacetylase to grow under phosphate-limiting conditions suggesting the role of acetyl phosphate as an energy source. Reverse transcription PCR demonstrated that the transcripts of acetate kinase and phospho-transacetylase genes in Synechocystis sp. PCC 6803 is up-regulated in response to phosphate limitation suggesting the importance of these two enzymes for energy metabolism in Synechocystis cells

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2228-2236
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• 2017

During menopausal transition, the imbalance of estrogen causes body weight gain. Although gut microbiome dysbiosis has been reported in postmenopausal obesity, it is not clear whether there is any difference in the microbiome profile between dietary-induced obesity and postmenopausal obesity. Therefore, in this study, we analyzed intestinal samples from ovariectomized mice and compared them with those of mice with high-fat diet-induced obesity. To further evaluate the presence of menopause-specific bacteria-gene interactions, we also analyzed the liver transcriptome. Investigation of the 16S rRNA V3-V4 region amplicon sequence profile revealed that menopausal obesity and dietary obesity resulted in similar gut microbiome structures. However, Bifidobacterium animalis was exclusively observed in the ovariectomized mice, which indicated that menopausal obesity resulted in a different intestinal microbiome than dietary obesity. Additionally, several bacterial taxa (Dorea species, Akkermansia muciniphila, and Desulfovibrio species) were found when the ovariectomized mice were treated with a high-fat diet. A significant correlation between the above-mentioned menopause-specific bacteria and the genes for female hormone metabolism was also observed, suggesting the possibility of bacteria-gene interactions in menopausal obesity. Our findings revealed the characteristics of the intestinal microbiome in menopausal obesity in the mouse model, which is very similar to the dietary obesity microbiome but having its own diagnostic bacteria.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.836-844
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• 2009

A denitrification bacterium was isolated from riverbed soil and identified as Ochrobactrum sp., whose specific enzymes for denitrification metabolism were biochemically assayed or confirmed with specific coding genes. The denitrification activity of strain G3-1 was proportional to glucose/nitrate balance, which was consistent with the theoretical balance (0.5). The modified graphite felt cathode with neutral red, which functions as a solid electron mediator, enhanced the electron transfer from electrode to bacterial cell. The porous carbon anode was coated with a ceramic membrane and cellulose acetate film in order to permit the penetration of water molecules from the catholyte to the outside through anode, which functions as an air anode. A non-compartmented electrochemical bioreactor (NCEB) comprised of a solid electron mediator and an air anode was employed for cultivation of G3-1 cells. The intact G3-1 cells were immobilized in the solid electron mediator, by which denitrification activity was greatly increased at the lower glucose/nitrate balance than the theoretical balance (0.5). Metabolic stability of the intact G3-1 cells immobilized in the solid electron mediator was extended to 20 days, even at a glucose/nitrate balance of 0.1.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.253-261
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• 2008

Isoflavone daidzein is a phytoestrogen widely distributed in Leguminosae and is especially rich in the soybean. The C6-C3 (rings B and C) unit of isoflavones is derived from the phenylpropanoid pathway and the remaining C6 (ring A) unit is from the polyketide pathway. This unique carbon skeleton is the result of isomerization of the flavone catalyzed by the isoflavone synthase, a cytochrome P450 enzyme. The isoflavones daidzein and genistein are present in the plant mostly in the glucosylated forms. However, in the human intestine, the glycosidic linkage is broken, and the free form is uptaked into blood stream. The free form is further metabolized into various reduction products to end up at the equol, which is known to have the most potent estrogenic effect among the metabolites. Several human intestinal bacteria that can convert daidzein into equol have been described, and the study into the chemistry and biochemistry of the daizein reduction would be rewarding to the improvement of the human health.

• Environmental Mutagens and Carcinogens
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• v.25 no.3
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• pp.97-103
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• 2005

The genotoxic effect of antimalarial drugs amodiaquine (AQ), mefloquine (MQ) and halofantrine (HF) was investigated in.at liver cells using the alkaline comet assay. AQ, MQ and HF at concentrations between $0-1000{\mu}mol/L$ significantly increased DNA strand breaks of rat liver cells dose-dependently. The order of induction of strand breaks was AQ>MQ>HF. The rat liver cells exposed to AQ and HF (200 and 400 ${\mu}mol/L$) and treated with (Fpg) the bacterial DNA repair enzyme that recognizes oxidized purine showed greater DNA damage than those not treated with the enzyme, providing evidence that AQ and HF induced oxidation of purines. Such an effect was not observed when MQ was treated with the enzyme. Treatment of cells with catalase, an enzyme inactivating hydrogen peroxide, decreased significantly the extent of DNA damage induced by AQ, and HF but not the one induced by MQ. Similarly quercetin, an antioxidant flavonoid at $50{\mu}mol/L$ attenuated the extent of the formation of DNA strand breaks by both AQ and HE. Quercetin, however, did not modify the effects of MQ. These results indicate the genotoxicity of AQ, MQ and HF in rat liver cells. In addition, the results suggest that reactive oxygen species may be involved in the formation of DNA lesions induced by AQ and HF and that, free radical scavengers may elicit protective effects against genotoxicity of these antimalarial drugs.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.103-108
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• 1990

The enzymatic studies on the methylglyoxal metabolism in yeast and bacterial cells indicated that organisms are equipped with the common and manifold systems for the detoxification of methylglyoxal. Among these systems, the glyoxalase I is the most important route for methylglyoxal detoxification. The molecular structure of glyoxalase I is apparently distinct from the enzyme sources, and zinc ion is an essential cofactor in enzyme activity. The gene for Pseudomonas putida glyoxalase I functioned as a scavenger of methylglyoxal and regulated the cell size of the bacterium. Comparison of the nucleotide sequence of the P. putida glyoxalase I gene with the N-terminal amino acid sequence of the purified enzyme revealed that the N-terminal methionine residue was removed after translation. Possible physiological role of glyoxalase I was also discussed.

• Korean Journal of Pharmacognosy
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• v.28 no.1
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• pp.35-41
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• 1997

Following ginsenoside-Rb1-hydrolyzing assay, strictly anaerobic bacteria were isolated from human feces and identified as Prevotella oris. The bacteria hydrolyzed ginsenoside Rb1 and Rd to $20-O-{\beta}-D-glucopyranosyl-20(S)-protopanaxadiol$ (I), ginsenoside Rb2 to $20-O-[{\alpha}-L-arabinofuranosyl (1{\rightarrow}6)-{\beta}-D-glucopyranosyl] - 20(S)-protopanaxadiol$ (ll) and ginsenoside Rc to $20-O-[{\alpha}-L-arabinofuranosyl (1{\rightarrow} 6){\beta}-D-g1ucopyranosyl]-20(S)-protopanaxadiol$ (III) like fecal microflora, but did not attack ginsenoside Re nor Rgl (Protopanaxatriol-type). Pharmacokinetic studies of ginseng saponins was also performed using specific pathogen free rats and demonstrated that the intestinal bacterial metabolites I-111, 20(S)- protopanaxatriol(IV) and 20(S)-protopanaxadiol(V) were absorbed from the intestines to $blood(0.4-5.1\;{\mu}g/ml)$ after oral administration with total saponin(1 g/kg/day).

• Korean Journal of Microbiology
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• v.21 no.3
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• pp.143-148
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• 1983

The occurrence of PZ-peptidase in Streptococcus sanguis and other oral bacteria was investigated utilizing washed whole cells as the enzyme source and PZ-pentapeptide as its substrate. Under the culture conditions employed in the present study. Streptococcus sanguis strains, fresh isolates as well as laboratory strains, produced a broad range of the enzyme activity (0.5-7.9 unit/mg protein). The strains of both Streptococcus mutans and Lactobacilli showed low levels of activity (0-0.5 unit/mg protein for S. mutans). As compared with the enzyme activities of other bacteria, a moderate range of activity was produced by the strains of Strptococcus mitis nad Strptoccus salivarius. Actinomyces strains, like those of S. sanguis, produced a varying amount of activity (0-9.8 unit/ mg protein). A possible involvement of the oral bacterial PZ-peptidase in the metabolism of human saliva proteins is discussed.

• Genomics & Informatics
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• v.16 no.3
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• pp.44-51
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• 2018

Fluoroquinolone (FQ) antibiotics are an important class of synthetic antibacterial agents. These are the most extensively used drugs for treating bacterial infections in the field of both human and veterinary medicine. Herein, the antibacterial and pharmacological properties of four fluoroquinolones: lomefloxacin, norfloxacin, ciprofloxacin, and ofloxacin have been studied. The objective of this study was to analyze the antibacterial characteristics of the different fluoroquinolones. Also, the pharmacological properties of the compounds including the Lipinski rule of five, absorption, distribution, metabolism, and excretion, LD50, drug likeliness, and toxicity were evaluated. We found that among all four FQ molecules, ofloxacin showed the highest antibacterial activity through in silico assays with a strong interaction (-38.52 kJ/mol) with the antibacterial target protein (topoisomerase-II DNA gyrase enzyme). The pharmacological and pharmacokinetic analysis also showed that the compounds ciprofloxacin, ofloxacin, lomefloxacin and norfloxacin have good pharmacological properties. Notably, ofloxacin was found to possess an IGC50 (concentration needed to inhibit 50% growth) value of $0.286{\mu}g/L$ against the Tetrahymena pyriformis protozoa. It also tested negative for the Ames toxicity test, showing its non-carcinogenic character.