• Biomolecules & Therapeutics
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• 제20권2호
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• pp.196-200
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• 2012

Role of metabolism by intestinal bacteria in arbutin-induced immunotoxicity was investigated in splenocyte cultures. Following an incubation of arbutin with 5 different intestinal bacteria for 24 hr, its aglycone hydroquinone could be produced and detected in the bacterial culture media with different amounts. Toxic effects of activated arbutin by intestinal bacteria on lymphoproliferative response were tested in splenocyte cultures from normal mice. Lipopolysaccharide and concanavalin A were used as mitogens for B- and T-cells, respectively. When bacteria cultured medium with arbutin was treated into the splenocytes for 3 days, the medium cultured with bacteria producing large amounts of hydroquinone induced suppression of lymphoproliferative responses, indicating that metabolic activation by intestinal bacteria might be required in arbutin-induced toxicity. The results indicated that the present testing system might be applied for determining the possible role of metabolism by intestinal bacteria in certain chemical-induced immunotoxicity in animal cell cultures.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.453-458
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• 1994

Intestinal microbial flora comprise one third of the large intestinal contents in human. They play a significant effects through beneficial and harmful action on the human health. This is the first study which examined the composition of the microflora of the general population in Korea. Bacteroides, Bifidobacterium, Eubacterium, Peptostreptococcus, Lactobacillus, Streptococcus, Escherichia coli, Staphylococcus, Clostridium perfringens, total aerobic bacteria and total anaerrobic bacteria were counted using various selective and non-selective media. Among the bacteria studied the number of Bifidobacterium were greatest in breast-fed infants(30-90 days old), whereas Streptocuccus and Bifidobacterium in bottle-fed infants. In 20-40 age group Bacteroides were predominant followed by Bifidobacterium and Eubacterium. In early group(over 65 years old) Bacteroides were predominant followed by Eubacterium and bifidobacterium. The frequency and number of Cl. perfringens were highest in dlderly group. These results confirm that the microfloral pattern in large intestine change during the life cycle of humans.

• Journal of Radiation Protection and Research
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• 제45권4호
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• pp.163-170
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• 2020

Background: Gut microflora contributes to the nutritional metabolism of the host and to strengthen its immune system. However, if the intestinal barrier function of the living body is destroyed by radiation exposure, the intestinal bacteria harm the health of the host and cause sepsis. Therefore, this study aims to trace short-term radiation-induced changes in the mouse gut microflora-dominant bacterial genus, and analyze the degree of intestinal epithelial damage. Materials and Methods: Mice were irradiated with 0, 2, 4, 8 Gy X-rays, and the gut microflora and intestinal epithelial changes were analyzed 72 hours later. Five representative genera of Actinobacteria, Firmicutes, and Bacteroidetes were analyzed in fecal samples, and the intestine was pathologically analyzed by Hematoxylin-Eosin and Alcian blue staining. In addition, DNA fragmentation was evaluated by the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Results and Discussion: The small intestine showed shortened villi and reduced number of goblet cells upon 8 Gy irradiation. The large intestine epithelium showed no significant morphological changes, but the number of goblet cells were reduced in a radiation dose-dependent manner. Moreover, the small intestinal epithelium of 8 Gy-irradiated mice showed significant DNA damaged, whereas the large intestine epithelium was damaged in a dose-dependent manner. Overall, the large intestine epithelium showed less recovery potential upon radiation exposure than the small intestinal epithelium. Analysis of the intestinal flora revealed fluctuations in lactic acid bacteria excretion after irradiation regardless of the morphological changes of intestinal epithelium. Altogether, it became clear that radiation exposure could cause an immediate change of their excretion. Conclusion: This study revealed changes in the intestinal epithelium and intestinal microbiota that may pave the way for the identification of novel biomarkers of radiation-induced gastrointestinal disorders and develop new therapeutic strategies to treat patients with acute radiation syndrome.

• 한국식품과학회지
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• 제28권5호
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• pp.981-986
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• 1996

김치는 한국인의 대표적인 발효식품으로서 정장 작용이 있다고 여겨져 왔다. 그러나 이를 입증하는 객관적인 자료가 미비한 상태이다. 이에 본 연구에서는 김치의 섭취가 인체의 장내 미생물에 미치는 영향을 조사하였다. 인체 실험대상자는 10명으로 실험기간중의 이들의 식이는 생균제, 항생제, 유산균 발효 제품을 제외한 자유식을 섭취하게 하였다. 실험 기간은 10주로 2주 간격으로 김치 비섭취 및 섭치 기간을 반복했으며 섭취 기간 중에는 매일 200 g의 김치를 섭취하게 하였다. 각 기간별로 분변의 장내 미생물 균총 분포도(Bacteroides, Bifidobacterium, Escherichia coli, Streptococcus, Lactobacillus, Leuconostoc, Staphylococcus, Clostridium perfringens), 변의 pH, 수분 함량 및 $\beta-glucosidase$, $\beta-glucuronidase$ 등의 효소활성도를 조사하였다. 조사 결과 김치의 섭취 기간 중 김치에 존재하는 젖산균인 Lactobacillus와 Leuconostoc의 수가 장내에서 유의적으로 증가하였으며(p<0.05) 그 외 조사된 다른 균총수의 변화는 유의적이지 않았다. 장내 유해효소로 알려진 $\beta-glucosidase$와 $\beta-glucuronidase$의 수준은 김치 섭취시에 유의적으로 감소하였다(p<0.05).

• 한국수의병리학회:학술대회논문집
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• 한국수의병리학회 2003년도 추계학술대회초록집
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• pp.1-5
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• 2003

A variety of different spirochaetal bacteria inhabit the large intestines of animals and man. This paper focuses on anaerobic intestinal spirochaetes of the genus Brachyspira (formerly Serpulina). Within the last few years, six new Brachyspira species have been officially name and/or renamed, and two other groups of these bacteria have been given provisional species names (Table 1). (omitted)

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.98-105
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• 1999

Intestinal bacteria comprise one-third of the contents of the large intestine in humans. Their interactions with the gastrointestinal immune system induce characteristic immunological responses which stimulate or suppress the host's defense system. RAW 264.7 murine cell line was used as a macrophage model to assess the effects of the exposure to the isolated human intestinal bacteria, Bacteroides, Bifidobacterium, Eubacterium, Streptococcus, and E. coli, on NO (nitric oxide), $H_2O_2$(hydrogen peroxide), and cytokines IL (interleukin)-6 and TNF (tumor necrosis factor)-a production. RAW 264.7 cells were cultured in the presence of heat-killed bacteria for 24 h at concentrations of 0-$50\mu$g/ml. Our results showed that Bacteroides and E. coli stimulated IL-6, TNF-$\alpha$, NO, and $H_2O_2$production at high levels even at $1\mu$g/ml, whereas Bifidobacterium, Eubacterium, and Streptococcus showed a low level of stimulation at $1\mu$g/ml, and a gradual increase as the cell concentration increased up to $50\mu$g/ml. This result suggests that gram-negative Bacteroides and E. coli are better able to stimulate macrophage than gram-positive Bifidobacterium, Streptococcus, and Eubacterium. The in vitro approaches employed here should be useful in further characterization of the effects of intestinal bacteria on gastrointestinal and systemic immunity.

• Asian-Australasian Journal of Animal Sciences
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• 제21권4호
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• pp.603-615
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• 2008

Dietary fiber is an inevitable component in pig diets. In non-ruminants, it may influence many physiological processes in the gastrointestinal tract (GIT) such as transit time as well as nutrient digestion and absorption. Moreover, dietary fiber is also the main substrate of intestinal bacteria. The bacterial community structure is largely susceptible to changes in the fiber content of a pig's diet. Indeed, bacterial composition in the lower GIT will adapt to the supply of high levels of dietary fiber by increased growth of bacteria with cellulolytic, pectinolytic and hemicellulolytic activities such as Ruminococcus spp., Bacteroides spp. and Clostridium spp. Furthermore, there is growing evidence for growth promotion of beneficial bacteria, such as lactobacilli and bifidobacteria, by certain types of dietary fiber in the small intestine of pigs. Studies in rats have shown that both phosphorus (P) and calcium (Ca) play an important role in the fermentative activity and growth of the intestinal microbiota. This can be attributed to the significance of P for the bacterial cell metabolism and to the buffering functions of Ca-phosphate in intestinal digesta. Moreover, under P deficient conditions, ruminal NDF degradation as well as VFA and bacterial ATP production are reduced. Similar studies in pigs are scarce but there is some evidence that dietary fiber may influence the ileal and fecal P digestibility as well as P disappearance in the large intestine, probably due to microbial P requirement for fermentation. On the other hand, fermentation of dietary fiber may improve the availability of minerals such as P and Ca which can be subsequently absorbed and/or utilized by the microbiota of the pig's large intestine.

• 생명과학회지
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• 제23권10호
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• pp.1295-1303
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• 2013

현재까지 밝혀진 사실에 의하면 지구상에는 55개 phylum의 bacteria와 13개 phylum의 archaea가 존재하여 총 68개 phylum 있으며, 대장에는 9개 phylum의 미생물이 존재하여 일반 토양환경이나 해양환경에 비하여 상대적으로 낮은 미생물 다양성을 가지고 있다. 장내 미생물의 다양성은 Host의 고유특성(genetic background, sex, age, immune system, gut motility)과 식이(nondigestible carbohydrates fat, prebiotics or probiotics), 항생제 섭취 등으로 인하여 영향 받으며, 이러한 영향이 에너지 저장 과정과 유전자 발현을 영향을 주고 나아가 비만과 같은 대사질환에 영향을 미친다. Probiotics는 숙주의 장내 균총을 개선하여 건강에 유익함을 줄 수 있는 살아있는 미생물을 말하며, 주로 lactic acid bacteria들이 이용되어 왔다. 최근 probiotics를 이용한 설사나 과민성대장증후군 등과 같은 질병 치료를 위하여 bacteriotherapy가 활용되고 있다. Prebiotics는 장내 미생물을 선택적으로 조절할 수 있는 식품 성분으로 inulin, fructo-oligosaccharides, galacto-oligosaccharides, lactulose 등이 이용되고 있으며, 최근에는 비만, 항암과 관련하여 대장 내 식이섬유소의 이용과 단쇄지방산(short-chain fatty acids) 생산에 대한 관심이 집중되고 있다. 다양한 nondigestible carbohydrates와 prebiotics, probiotics에 의해서 조절되는 대장 내 특정 미생물 종을 규명하고, 이들 미생물 종이 생산하는 단쇄지방산과 같은 대사산물들과 질병과의 연관성 규명하는 대장 미생물 연구가 더욱 필요하다.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.443-445
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• 1994

Eubacterium is one of the predominant bacteria in the human large intestine. currently ES (Eubacterium Selective) medium developed by T. Mitsuoka is commonly used as a selective medium. neomycin sulfate which is one of the selective agents of ES medium inhibited about 50% of the growth of Eubacterium isolated, whereas malidixic acid inhibited only 5% while inhibiting other intestinal bacteria. NES medium which replaced neomycin with nalidixic acid in the ES medium was designed and shown to be better for the isolation and enumeration of Eubacterium sp. than ES medium.

• 한국식품과학회지
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• 제25권6호
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• pp.694-697
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• 1993

Bifidobacterium과 기타 장내 세균을 두유에 배양하여 배양특성을 살펴보았다. 균주들은 다음과 같이 Bifidobacterium longum, Lactobacillus acidophilus, Bacteroides fragilis, Eubacterium limosum, Clostridium perfringens, E. coli.를 사용하였다. 이들중 B. longum만이 높은 활성의 ${\alpha}-galactosidase$를 생산해 두유의 주요 당인 raffinose와 stachyose를 이용하였고 가장 높은 산 생성을 보여주었다. 16시간 배양후에 B. longum은 $1.5{\times}10^{8}\;CFU$에 이르렀다. 또한 B. longum은 ${\alpha}-galactosidase$이외에 ${\alpha}-galactosidase$와 ${\beta}-galactosidase$의 활성도 다른 균주에 비하여 가장 높았다.