• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.823-830
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• 2005

This study was undertaken to evaluate the effect of bacteria-derived $\beta$-glucan fiber on serum lipids, adiposity and uncoupling protein (UCP) expression in rats. In order to induce obesity, Sprague-Dawley weanling male rats were allowed free access to AIN-76A diet until 4 weeks of age, and fed high-fat diet (beef tallow, $40\%$ of calories as fat) for 6 weeks until 10 weeks of age. Rats were then fed with $0\%$ thigh- fat control group), $1\%$, or $5\%$ bacterial ~-glucan supplemented high-fat diets (w/w) for another 6 weeks. For comparison, normal control group was fed with AIN-76 diet $11.7\%$ fat). Supplementation with bacterial $\beta$-glucan resulted in a significant reduction of high-fat-induced white fat (i.e., visceral and peritoneal fat) development, adipocyte hypertrophy, and development of hyperinsulinemia and hyperleptinemia. Serum triglyceride, total cholesterol, and free fatty acid levels were greatly reduced, but, HDL-cholesterol concentrations were increased by bacterial $\beta$-glucan supplementation. Serum leptin level was lower in the $\beta$-glucan groups than in the high-fat group. The expression of UCPs (UCP1, UCP2, and UCP3) in brown adipose tissue (BAT) were significantly increased by $5\%$ bacterial $\beta$-glucan-containing diet. This study suggests that the anti-obesity effect of $5\%$ bacterial $\beta$-glucan is attributed to upregulation of UCPs and inefficient energy utilization.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.4
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• pp.495-504
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• 2017

Objective: Manipulating the fermentation to improve the performance of the ruminant has attracted the attention of both farmers and animal scientists. Propionate salt supplementation in the diet could disturb the concentration of propionate and total volatile fatty acids in the rumen. This study was conducted to evaluate the effect of calcium propionate supplementation on the ruminal bacterial community composition in finishing bulls. Methods: Eight finishing bulls were randomly assigned to control group (CONT) and calcium propionate supplementation (PROP) feeding group, with four head per group. The control group was fed normal the total mixed ration (TMR) finishing diet, and PROP group was fed TMR supplemented with 200 g/d calcium propionate. At the end of the 51-day feeding trial, all bulls were slaughtered and rumen fluid was collected from each of the animals. Results: Propionate supplementation had no influence the rumen fermentation parameters (p>0.05). Ruminal bacterial community composition was analyzed by sequencing of hypervariable V3 regions of the 16S rRNA gene. The most abundant phyla were the Firmicutes (60.68%) and Bacteroidetes (23.67%), followed by Tenericutes (4.95%) and TM7 (3.39%). The predominant genera included Succiniclasticum (9.43%), Butyrivibrio (3.74%), Ruminococcus (3.46%) and Prevotella (2.86%). Bacterial community composition in the two groups were highly similar, except the abundance of Tenericutes declined along with the calcium propionate supplementation (p = 0.0078). Conclusion: These data suggest that the ruminal bacterial community composition is nearly unchanged by propionate supplementation in finishing bulls.

• Journal of Microbiology and Biotechnology
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• v.26 no.7
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• pp.1320-1332
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• 2016

Light hydrocarbons accumulated in subsurface soil by long-term microseepage could favor the anomalous growth of indigenous hydrocarbon-oxidizing microorganisms, which could be crucial indicators of underlying petroleum reservoirs. Here, Illumina MiSeq sequencing of the 16S rRNA gene was conducted to determine the bacterial community structures in soil samples collected from three typical oil and gas fields at different locations in China. Incubation with n-butane at the laboratory scale was performed to confirm the presence of "universal microbes" in light-hydrocarbon microseepage ecosystems. The results indicated significantly higher bacterial diversity in next-to-well samples compared with background samples at two of the three sites, which were notably different to oil-contaminated environments. Variation partitioning analysis showed that the bacterial community structures above the oil and gas fields at the scale of the present study were shaped mainly by environmental parameters, and geographic location was able to explain only 7.05% of the variation independently. The linear discriminant analysis effect size method revealed that the oil and gas fields significantly favored the growth of Mycobacterium, Flavobacterium, and Pseudomonas, as well as other related bacteria. The relative abundance of Mycobacterium and Pseudomonas increased notably after n-butane cultivation, which highlighted their potential as biomarkers of underlying oil deposits. This work contributes to a broader perspective on the bacterial community structures shaped by long-term light-hydrocarbon microseepage and proposes relatively universal indicators, providing an additional resource for the improvement of microbial prospecting of oil and gas.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.123-131
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• 2007

Effect of nitrogen-load condition on hydrogen ($H_2$) production and bacterial community in a continuous anaerobic hydrogen fermentation were investigated. The slight $H_2$ production on extremely low nitrogen-load condition (C/N ratio: 180) at the start-up period. The highest $H_2$ production was obtained when the C/N ratio was 36, the $H_2$ production yield ($mol-H_2/mol-glucose$) reached to 1.7, and it was indicated that Clostridium pasteurianum mainly contributed to the $H_2$ production. The $H_2$ production was decreased on both the lower (C/N: 72) and higher (C/N: 18) nitrogen-load conditions. The excess nitrogen-load was not always suitable for the hydrogen production. The fluctuation of $H_2$ production seemed to be caused by a change in the bacterial community according to the nitrogen-load condition, while a recovery of $H_2$ productivity was possible by a control of nitrogen-load condition through the bacterial community change. When the nitrogen-load condition was not suitable for hydrogen production, the lactic acid concentration was increased and also lactic acid bacteria were definitely detected, which suggested that the competition between hydrogen fermentator and lactic acid producer was occurred. These results demonstrated that the nitrogen-load condition affect on the $H_2$ productivity through the change of bacterial community in anaerobic hydrogen fermentation.

• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.545-554
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• 2018

Background: The increasing morbidity and mortality rates associated with Acinetobacter baumannii are due to the emergence of drug resistance and the limited treatment options. We compared characteristics of colistin-resistant Acinetobacter baumannii (CR-AB) clinical isolates recovered from patients with and without prior colistin treatment. We assessed whether prior colistin treatment affects the resistance mechanism of CR-AB isolates, mortality rates, and clinical characteristics. Additionally, a proper method for identifying CR-AB was determined. Methods: We collected 36 non-duplicate CR-AB clinical isolates resistant to colistin. Antimicrobial susceptibility testing, Sanger sequencing analysis, molecular typing, lipid A structure analysis, and in vitro synergy testing were performed. Eleven colistin-susceptible AB isolates were used as controls. Results: Despite no differences in clinical characteristics between patients with and without prior colistin treatment, resistance-causing genetic mutations were more frequent in isolates from colistin-treated patients. Distinct mutations were overlooked via the Sanger sequencing method, perhaps because of a masking effect by the colistin-susceptible AB subpopulation of CR-AB isolates lacking genetic mutations. However, modified lipid A analysis revealed colistin resistance peaks, despite the population heterogeneity, and peak levels were significantly different between the groups. Conclusions: Although prior colistin use did not induce clinical or susceptibility differences, we demonstrated that identification of CR-AB by sequencing is insufficient. We propose that population heterogeneity has a masking effect, especially in colistin non-treated patients; therefore, accurate testing methods reflecting physiological alterations of the bacteria, such as phosphoethanolamine-modified lipid A identification by matrix-assisted laser desorption ionization-time of flight, should be employed.

• Toxicological Research
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• v.12 no.1
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• pp.17-20
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• 1996

The effect of Fumonisin B1, a mycotoxin produced by Fusarium moniliforme on bacterial viruses P1 and Lambda, was investigated by the virus plaque assay. Fumonisin B1 inhibited the P1 viral multiplication in the concentration range from $100{\mu}g$/ml to $400{\mu}g$/ml. The inhibition was Fumonisin B1 concentration-dependent. Another bacterial virus Lambda multiplication was also inhibited by lower concentration of Fumonisin B1 ($10{\mu}g$/ml~$50{\mu}g$/ml). This inhibition was dependent on Fumonisin B1 and on virus-Fumonisin B1 reaction time. Sensitivity of bacteriophage Lambda to Fumonisin B1 was higher than that of P1 virus. Lambda vital DNA was treated in vitro with Fumonisin B1 at various concentration. Significant DNA fragmentation by Fumonisin 191 was observed in the agarose gel electrophoresis. Lambda viral DNA was partially digested even in the Fumonisin B1 $10{\mu}g$ and the level of its fragmentation was dependent on Fumonisin B1 amount up to $30{\mu}g$ per assay.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.1
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• pp.11-20
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• 2006

Objective : This experimental study was performed to investigate the effect of herbal eye drops, Sean-tang and Coptidis rhizoma on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa keratitis. Methods : After administering herbal eye drops (Sean-tang, Coptidis rhizoma) on Staphylococcus ausreus, Staphylococcus. epidermidis and Pseudomonas aeruginosa, I measured MIC and the size of inhibition zone. MIC was measured by dropping to $50{\mu}{\ell}$ according to density(l00%, 10%, 1%, 0.1%). Anti-bacterial potency was measured by the size of inhibition zone with change of volume. Result : On Staphylococcus aureus, Staphylococcus epidermidis, Coptidis rhizoma showed the highest anti-bacterial potency and on Pseudomonas aeruginosa, Sean-tang, Coptidis rhizoma was nor anti-bacterial potency. Conclusions : The present author think that the herbal eye drops, Sean-tang and Coptidis rhizoma can be used to cure Staphylococcus aureus, Staphyloccus epidermidis keratitis and if further study is performed, the use of the herbal eye drops will be valuable and beneficial in the clinical medicines.

• Geomechanics and Engineering
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• v.7 no.6
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• pp.649-663
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• 2014

In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has become popular as a ground improvement technique for sandy soil. However, this technique was not applied to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work. Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate. Change in the permeability was measured before and after biocementation. The test results showed that the pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found that the biocementation can be considered as an effective method for reducing permeability of organic soil. The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray (EDX) analysis.

• KSBB Journal
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• v.18 no.2
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• pp.94-99
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• 2003

The effect of medium composition on the production of bacterial cellulose (BC) by Gluconacetobacter hansenii PJK was investigated. The addition of yeast extract and peptone in the medium increased the production yield (Y/sub p/s/) of BC. The amount of BC produced by G. hansenii PJK was constant if the initial pH of the medium was in the range 4.5 to 6.0. Strains from the supernatant of the culture medium produced more BC than those from inside the BC. BC production was dependent on glucose metabolism, and the addition of fructose or lactate as a carbon source converted cells to Cel/sup -/ mutants. Cel/sup -/ mutants produced by the addition of fructose or lactate to the medium caused 73% or 30% decreases in BC production, respectively. The addition of succinate, which is one of the constituents of the TCA cycle, did not affect the production of BC.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.199-202
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• 2004

Cellulolytic bacterial strains have been isolated from the faeces of wild (blackbuck, Antilope cervicapra; nilgai, Baselophus tragocamelus chinkara, Gazella gazella spotted deer, Axis axis and hog deer, Cervus porcinus) and rumen liquor of domestic (sheep, Ovis aries) ruminants. Five best cellulose degrading bacterial isolates (Ruminococcus sp.) were used as microbial feed additive along with buffalo rumen liquor as inoculum to study their effect on digestibility of feed and enzyme production in in vitro conditions. The bacterial isolate from chinkara (CHI-2) showed the highest per cent apparent dry matter (DM) digestibility ($35.40{\pm}0.60$), true dry matter digestibility ($40.80{\pm}0.69$) and NDF ($26.38{\pm}0.83$) digestibility (p<0.05) compared to control ($32.73{\pm}0.56$, $36.64{\pm}0.71$ and $21.16{\pm}0.89$, respectively) and other isolates at 24 h of incubation with lignocellulosic feeds (wheat straw and wheat bran, 80:20). The same isolate also exhibited the highest activities of fibre degrading enzymes like carboxymethylcellulase, xylanase, ${\beta}$-glucosidase and acetyl esterase. The bacterial isolate from chinkara (Gazella gazella) appears to have a potential to be used as feed additive in the diet of ruminants for improving utilization of nutrients from lignocellulosic feeds.