• 대한미생물학회지
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• 제35권1호
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• pp.41-48
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• 2000

Bacteroides fragilis and Escherichia coli, normal colonic inhabitants, are the most frequently isolated bacteria in infected tissues, particularly in intraabdominal abscesses. This study was designed to determine whether enteric bacteria may alter the B. fragilis-induced expression of pro inflammatory cytokines in mouse peritoneal tissue (MPT). After C57BL/6 mice were inoculated with abscess-forming mixture containing B. fragilis in the presence or absence of E. coli, RNA was extracted from MPT. Expression of interleukin (IL)-$1{\alpha}$ and tumor necrosis factor $(TNF){\alpha}$ mRNA was assessed using RT-PCR and standard RNA. Each cytokine protein was also measured by ELISA. The co-inoculation of E. coli into mouse peritoneal cavity advanced the onset of abscess development by B. fragilis infection. When mouse was co-infected with E. coli and B. fragilis intraperitoneally, there was a synergistic increase in the expression of IL-$1{\alpha}$ and $TNF{\alpha}$ mRNA in MPT and this was paralleled by increased cytokine protein secretion. Mixed inoculation of heat-killed E. coli and B. fragilis did not cause a synergistic increase in those cytokine mRNA expression. These results suggest that enteric bacteria may significantly affect proinflammatory cytokine signal produced by host peritoneal cavity in response to B. fragilis infection.

• Toxicological Research
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• 제29권2호
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• pp.129-135
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• 2013

Salmonella is one of the major pathogenic bacteria that cause food poisoning. This study investigated whether heat-killed as well as live Lactobacillus protects host animal against Salmonella infection. Live and heat-killed Lactobacillusacidophilus was administered orally to Sprague-Dawley rats for 2 weeks before the rats were inoculated with Salmonella. Rise in body temperature was moderate in the group that was treated with heat-killed bacteria as compared to the Salmonella control group. The mean amount of feed intake and water consumption of each rat in the heat-killed bacteria group were nearly normal. The number of fecal Salmonellae was comparable between the live and the heat-killed L. acidophilus groups. This finding shows that L. acidophilus facilitates the excretion of Salmonella. Moreover, the levels of pro inflammatory cytokines, including tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta, in the heat-killed L. acidophilus group were significantly lower when compared to the levels in the Salmonella control group. These results indicate that nonviable lactic acid bacteria also could play an important role in preventing infections by enteric pathogens such as Salmonella.

• 대한수의학회지
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• 제40권1호
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• pp.72-80
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• 2000

Lipopolysaccharides (LPS) of Pasteurella multocida (P multocida) and several Gram-negative bacterial pathogens were analyzed by methanolysis, trifluoroacetylation and gas chromatography (GC) on a fused-silica capillary column. The GC analysis indicated that LPS prepared from a strain of P multocida by phenol-water (PW) or trichloroacetic acid (TCA) extraction were quite different in chemical composition. However, LPS prepared from Salmonella enteritidis by the two extraction methods were very similar. PW-LPS extracts from different Pasteurella strains of a serotype had essentially identical GC patterns. Endotoxic LPS extracted from 16 different serotypes of P multocida by PW or by phenol-chloroform-petroleum ether procedures yielded chromatograms indicating similar composition of the fatty acid moieties but minor differences in carbohydrate content. When the chemical composition of endotoxic LPS extracted from several Gram-negative bacteria (P multocida, Pasteurella hacmolytica, Haemophilus somnus, Actinobacillus ligniersii, Brucella abortus, Treponema hyodysenteriae, Escherichia coli, Bacteriodes fragilis, Salmonella abortus equi and Salmonella enteritidis) were examined, each bacteria showed a unique GC pattern. The carbohydrate constituents in LPS of various Gram-negative bacteria were quite variable not only in the O-specific polysaccharides but also in the core polysaccharides. The LPS of closely related bacteria shared more fatty acid constituents with each other than with unrelated bacteria.

• 한국식품영양학회지
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• 제23권2호
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• pp.171-177
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• 2010

Serratia marcescens catabolic threonine dehydratase는 streptomycin sulfate treatment, Sephadex G-200 gel filtration, AMP-Sepharose 4B affinity chromatography 등의 방법으로 정제하였는데, 최종 단계에서 회수율은 15.5%이었으며 50배 정제되었다. Native 분자량은 native pore gradient polyacrylamide gel electrophoresis(PAGE) 방법으로는 120,000이었다. SDS-PAGE에 의한 subunit의 분자량은 30,000이었고, 즉 S. marcescens 효소는 4개의 동일한 subunit으로 구성된 homo-tetrameric protein임이 판명되었다. S. marcescens 효소의 L-threonine에 대한 Km값은 AMP가 있는 조건에서 7.3 mM, AMP가 없는 조건에서 92 mM이었다. S. marcescens 효소는 효소 1 mole 당 각각 2 mole의 pyridoxal 5'-phosphate(PLP), 16개의 free-SH group을 가지고 있었다. S. marcescens 효소는 AMP의 존재 하에서 $\alpha$-ketobutyrate, pyruvate, glyoxylate, phosphoenol pyruvate(PEP)에 의해 효소 활성이 억제되었으며, cAMP와 ADP에 의해서는 효소 활성이 증가되었다. 효소학적 성질면에서 S. marcescens 효소는 E. coli 효소보다는 S. typhimurium 효소와 유사하였다. 한편, E. coli 효소는 cAMP에 의하여 효소 활성이 증가되고, S. typhimurium 효소는 ADP에 의해 효소 활성이 증가되는 것과 다르게, S. marcescens 효소는 cAMP와 ADP 모두 효소 활성이 증가되었다. 따라서 이상의 연구 결과들은 세 enteric bacteria의 catabolic threonine dehydratase가 서로 작은 차이점이 있다는 것을 반영하며, 이러한 사실을 규명하기 위해서는 향후 보다 심층적인 연구를 수행하여야 할 것으로 사료된다.

• Journal of Dairy Science and Biotechnology
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• 제32권2호
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• pp.141-145
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• 2014

시장에는 프로바이오틱스를 포함한 무수히 많은 제품이 판매되고 있는데, 우리에게 어떤 이로운 점을 줄 수 있는지 궁금해 한 적이 있었을 것이다. 프로바이오틱스는 기본적인 영양 측면을 배제하고, 우리가 유효한 양을 섭취하였을 때 건강상의 이점을 주는 살아있는 미생물로 정의된다. 프로바이오틱스는 유용하고 건강에 좋은 미생물로도 불려지고 있으며, 다음과 같은 다섯 가지 측면에서 건강 기능성이 있는 것으로 강조되어 왔는데, 1) 대장암 및 IBS와 같은 다른 대장(결장)관련 질병의 발병율 감소, 2) 면역 시스템의 촉진, 3) 항고혈압 및 항콜레스테롤 작용, 4) 장내세균에 작용하는 항생제의 효과를 경감시키고, 5) 위장관 감염을 예방시키는 점이다. 그러나 이러한 건강기능 작용들에 대한 과학적인 근거가 충분히 구축되어 있지는 않아, 유럽식품 위생위원회(Euroupe Food Safety Authority)는 항생제 투여에 따른 설사증상의 완화와 같은 건강기능 표시를 금지하고 있어, 프로바이오틱스의 작용기전에 대한 연구가 필요한 시점이라 하겠다.

• Journal of Microbiology
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• 제40권4호
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• pp.327-330
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• 2002

The purpose of this research was to test multiplex polymerase chain reaction in investigating the microbiological quality of the risky surfaces in social living places of a military base where over 15 thousand people live together. In 22 samples of 99, there were no bacteria. Only four of the samples contained Shigella, and one of them contained Salmonella, but 77 of the samples contained thermotolerant coliform organisms. There was no statistically significant difference among the microbiological quality of different sites and different equipment surfaces (p>0.05).

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.165-168
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• 2001

Regulation of pyrimidine nucleotide synthesis has been studied extensively in enteric bacteria and Bacillus species. Varieties of control modes have been proposed for regulation of pyrimidine nucleotide biosynthetic (pyr) genes. In Bacillus caldolyticus and B. subtilis, it has been proved that pyrimidine de novo biosynthetic operon is controlled by a regulatory protein PyrR-mediated attenuation. Another Gram-positive bacteria including Enterococcus faecalis, Lactobacillus plantarum, and wctococcus lactis have been found to constitute a pyr gene cluster containing the pyrR gene. In addition, it has been proposed that the structure of the 5' leader region of the Gram-negative extreme thermophile Thermus strain Z05 pyr operon provides a novel mechanism of PyrR-dependent coupled transcription-translation attenuation. Bacterial genome sequencing projects have identified the PyrR homologues in Haemophilus influenzae, Synechocystis sp., Mycobacterium tuberculosis, Streptococcus pneumoniae, S. pyogenes, and Clostridium acetobutylicum, which are currently investigating for their physiological functions.

• Journal of Animal Science and Technology
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• 제65권1호
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• pp.132-148
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• 2023

Ruminants are the main contributors to methane (CH₄), a greenhouse gas emitted by livestock, which leads to global warming. In addition, animals experience heat stress (HS) when exposed to high ambient temperatures. Organic trace minerals are commonly used to prevent the adverse effects of HS in ruminants; however, little is known about the role of these minerals in reducing enteric methane emissions. Hence, this study aimed to investigate the influence of dietary organic trace minerals on rumen fermentation characteristics, enteric methane emissions, and the composition of rumen bacteria and methanogens in heat-stressed dairy steers. Holstein (n=3) and Jersey (n=3) steers were kept separately within a 3×3 Latin square design, and the animals were exposed to HS conditions (Temperature-Humidity Index [THI], 82.79 ± 1.10). For each experiment, the treatments included a Control (Con) consisting of only basal total mixed rations (TMR), National Research Council (NRC) recommended mineral supplementation group (NM; TMR + [Se 0.1 ppm + Zn 30 ppm + Cu 10 ppm]/kg dry matter), and higher concentration of mineral supplementation group (HM; basal TMR + [Se 3.5 ppm + Zn 350 ppm + Cu 28 ppm]/kg dry matter). Higher concentrations of trace mineral supplementation had no influence on methane emissions and rumen bacterial and methanogen communities regardless of breed (p > 0.05). Holstein steers had higher ruminal pH and lower total volatile fatty acid (VFA) concentrations than Jersey steers (p < 0.05). Methane production (g/d) and yield (g/kg dry matter intake) were higher in Jersey steers than in Holstein steers (p < 0.05). The relative abundances of Methanosarcina and Methanobrevibacter olleyae were significantly higher in Holstein steers than in Jersey steers (p < 0.05). Overall, dietary organic trace minerals have no influence on enteric methane emissions in heat-stressed dairy steers; however, breed can influence it through selective alteration of the rumen methanogen community.

• Archives of Pharmacal Research
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• 제28권6호
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• pp.660-666
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• 2005

The intestinal microbiota are important to the host with regard to resistance they impart against bacterial infections and their involvement in mediating metabolic functions. Lactic acid producing bacteria such as Lactobacillus play an important physiological role in these matters. The aim of the present study was to isolate Lactobacillus sp. that inhibits enteric pathogens. Initially, 17 isolates from healthy Koreans were collected on Lactobacillus selective medium. Resistance of the isolates to antibiotics including rifampicin, streptomycin, clindamycin and vancomycin was measured. One of the isolate was identified as Lactobacillus ruminus on the basis of bacterial cell morphology, cultural characteristic and biochemical characteristics, 16S rRNA sequence analysis and PCR-RAPD. Antimicrobial activity of the bacterium against Vancomycin Intermediate Resistant Staphylococcus aureus (VISA) and Vancomycin-Resistant Enterococci (VRE) was measured. About $10^4$ cells of VISA or VRE were mixed with 1, 5, and 9 mL of L. ruminus SPM 0211 and the final volume was adjusted to 10 mL with brain heart infusion (BHI) broth. The cell suspension was incubated for 3, 6, 9, and 24 h, serially diluted and then plated on BHI agar plates. As numbers of L. ruminus SPM 0211 were increased, viable cell count of VISA and VRE decreased. The strongest antimicrobial activity of SPM 0211 was observed after 9 h incubation in any mixture, almost completely inhibiting the growth of these two bacteria. The results suggest that the freshly isolated L. ruminus SPM 0211 may be used as a pro-biotic microbe that prevents the colonization of enteric pathogens and can thereby promote good gastrointestinal health.

• 동아시아식생활학회지
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• 제6권2호
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• pp.187-194
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• 1996

닭고기를 멸균 증류수, 5% potassium sorbate, 5% sodium acid pyrophosphate, 2.5% potassium sorbate와 2.5% sodium acid pyrophosphate 혼합용액으로 처리하여 4$^{\circ}C$에서 보관하면서 미생물 수의 변화, pH 변화, TBA 값의 변화를 측정하였다. Potassium sorbate와 sodium acid pyrophosphate 혼합용액의 처리는 중온성 균과 저온성 균의 성장억제에 대한 상승효과를 주었고, 장내 세균의 성장억제에도 효과적이었다. 효모와 곰팡이의 성장억제에는 potassium sorbate의 처리가 가장 효과적이었다. Potassium sorbate와 sodium acidpyrophosphate 혼합용액 과 potassium sorbate 처리는 닭고기의 저온성 균과 장내 세균의 유도기를 연장시켰다. 닭고기의 pH는 저장기간 중 높아졌으며, 이것이 항미생물 효과의 감소에 영향을 주었을 것으로 추정되었다. TBA 값은 sodium acid pyrophosphate처리시 가장 낮게 나타나 지방함량이 많은 식품에 사용될 경우 항미생물 효과뿐만 아니라 항산화효과도 함께 줄 수 있을 것으로 기대되었다.