• The Korean Journal of Ecology
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• 제26권6호
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• pp.307-312
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• 2003

본 연구는 2000년 7월에 전남 장흥군에서 채집한 불가사리의 장내에 존재하는 종속영양세균의 다양성에 대해서 알아보았다. 불가사리 장내에 존재하는 균체수를 측정하였으며, 순수 분리된 균주를 대상으로 16S rDNA 증폭기법을 이용하여 세균의 다양성을 조사하였다. 불가사리 장내에 분포하는 종속영양세균의 균체수는 8.65${\pm}$0.65${\times}10^3\;dfu\;g^{-1}$이었다. 29 균주의 세균이 순수 분리되었으며, 그 중 그람양성 세균은 분리된 균주의 59% (17균주)를 차지하였다. 불가사리 장내에서 분리된 균주는 Bacillus속, Microbacterium 속, 그리고 Marinobacter 속 등이 우점이었으며, 이외에도 Staphylococcus 속, Psychrobacter 속, Paracoccus 속, Erythrobacter 속, Zoogloea 속, Kocuria 속과 Arthrobacter 속 등이 포함되었다. 분리된 균주 가운데 Bacillus 속에 속하는 8균주 중 3균주는 type strain과 97% 이상의 유사도를 보인 반면, 5 균주는 유사도가 90%로 비교적 낮은 유사도를 보여 현재까지 알려지지 않은 신종일 가능성이 높다고 하겠다.

• Asian-Australasian Journal of Animal Sciences
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• 제10권5호
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• pp.495-504
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• 1997

Three media, i. e., MOD-SD, M98-5 and M98-5 supplemented with chicken fecal extract were tested as isolation media for anaerobic bacteria present in the duodenum, jeju-ileum and cecum of chicken. The results showed that the mean colony counts of medium M98-5 were similar with those of MOD-SD medium in all intestinal samples at the incubation periods of 2, 6 and 10 days. Supplementation with chicken fecal extract of M98-5 medium significantly increased (p < 0.05) the colony counts of bacteria from the duodenum, jeju-ileum and cecum. The colony counts at 6-day incubation were similar with those at 10-day incubation, but were much higher than the counts at 2-day incubation. The major types of bacteria found in the duodenum and jeju-ileum of chicken were tentatively identified as Lactobacillus, Streptococcus and E. coli. In the cecum, ten tentatively identified groups of bacteria, namely, Streptococcus, Staphylococcus, Lactobacillus, E. coli, anaerobic coccus, Eubacterium, Propionibacterium, Clostridium, Fusobacterium and Bacteroides were isolated. Anaerobes were found to comprise nearly the entire microbial population of the cecum. Predominating in all sections of the intestine were homofermentative lactobacilli. The main Lactotacillus species in chicken intestine were L. acidophilus, L. fermentum and L. brevis.

• Molecules and Cells
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• 제42권3호
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• pp.228-236
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• 2019

CD4 T cells differentiate into $ROR{\gamma}t/IL$-17A-expressing cells in the small intestine following colonization by segmented filamentous bacteria (SFB). However, it remains unclear whether SFB-specific CD4 T cells can differentiate directly from naïve precursors, and whether their effector differentiation is solely directed towards the Th17 lineage. In this study, we used adoptive T cell transfer experiments and showed that naïve CD4 T cells can migrate to the small intestinal lamina propria (sLP) and differentiate into effector T cells that synthesize IL-17A in response to SFB colonization. Using single cell RT-PCR analysis, we showed that the progenies of SFB responding T cells are not uniform but composed of transcriptionally divergent populations including Th1, Th17 and follicular helper T cells. We further confirmed this finding using in vitro culture of SFB specific intestinal CD4 T cells in the presence of cognate antigens, which also generated heterogeneous population with similar features. Collectively, these findings indicate that a single species of intestinal bacteria can generate a divergent population of antigen-specific effector CD4 T cells, rather than it provides a cytokine milieu for the development of a particular effector T cell subset.

• 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.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.226.3-227
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• 2003

Lactic acid bacteria have been considered as the most beneficial probiotic organisms contributing to inhibition of harmful and putrefactive intestinal bacteria. Among them, Bifidobacterium spp. has been considered as one of the most beneficial probiotic organism that can improve the health of humans, since it is one of the major bacteria flora in human intestine. However, the harmful enzyme-inhibitory activity of lactic acid bacteria of Kimchi, which is a representative Korean fermented food has not been evaluated. (omitted)

• 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.

• 한국응용곤충학회지
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• 제53권1호
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• pp.15-26
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• 2014

다양한 먹이 조건에서 생활하는 아메리카동애등에(Hermetia illucens)는 장내 세균의 의존성을 가질 수 있다. 이 가설을 증명하기 위해 본 연구는 종령 유충의 소화관에 존재하는 세균을 분리, 동정하고 효소활성 및 항균 능력을 분석하였다. 종령 유충의 소화관은 몸 체장에 약 7 배의 길이를 나타냈다. 한 개체의 소화관 내 존재하는 세균 수는 $5.0{\times}10^6$ cfu로 98% 이상이 후장에 존재했다. 소화관에는 3 종류의 상이한 세균이 존재했고, 미생물 동정 장치는 이들이 각각 Morganella morganii, Providencia rettgeri 및 Bacillus halodurans로 동정하였다. 이들 소화관 세균을 16S rDNA 서열을 분석한 결과 이 외에 Proteus mirabilis, Providencia alcalifaciens, Providencia sp.를 검출하였다. 이들 장내세균은 항생제 내성을 보였고, 타 미생물의 성장을 억제하였다. 또한 섬유소, 지질, 단백질 및 탄수화물의 분해 능력을 보유하였다. 본 연구 결과들은 아메리카동애등에 소화관에 유용성이 높은 세균을 보유하고 있다고 제시하였다.

• 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.

• 한국축산식품학회지
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• 제32권2호
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• pp.149-154
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• 2012

It is known that lactic-acid bacteria (LAB) helps keeping the intestine healthy and to enhance its immunologic competence. In addition, it is known to control the composition of the enterobacteria and the intestinal inflammatory reaction by inducing immunological enhancement. This study was performed, in a mouse model, to test the treatment and preventive effects of LAB of inflammatory bowel disease (IBD), which was induced by a blend of LAB-administering trinitrobenzene sulfonic acid (TNBS). To obtain the animal model of IBD, 2% TNBS was rectally administered once to a five-week-old male Balbc/J mouse. A probiotic combination was administered to the prevention group five times a week for eight weeks before the inducement of enteritis, and the mixture was administered to the treatment group five times a week, after the administration of TNBS. The changes in the levels of the cytokines of the lymph nodes and the tissue of the large intestine were observed, both with the naked eye and with a microscope. The observation showed that the levels of inflammatory cells, infiltration, and necrosis were much lower in the LAB-administered groups than in that of the control group. In addition, the inflammatory cytokines (e.g., TNF-${\alpha}$, IL-17A) decreased in the lymph nodes and the tissues of the large intestine. The results indicated that the administration of the combination to the animal model suppressed the inflammatory cytokines in the large intestine and in the lymph nodes, which in turn suppressed the progression of colitis.

• 한국미생물·생명공학회지
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• 제27권1호
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• pp.23-27
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• 1999

The development and industrial application of intestinal anaerbic bacteria is highly important in the munufacture of foodstuffs and medical products. We have conducted studies, screening anaerobic intestinal bacteria for acid and bile tolerance and for pathogens suppression in the intestine of swine. One such study was taxonomic in nature and dealt with the isolate's biochemical responses. The results indicated that the BSA-131 strian ioslated. which suppressed various pathogens (13 typical strains), were identified as Lactobacillus reuterii. The strain, which named L. reuterii BSA-131, was able to tolerate acid condition down to pH2 and could also tolerate bile at 5%. The strain exhibited resistance to a range of antibiotics including, cephalexin, erythromycin, flumequine, furazolidine, gentamycin, penicillin G, norfloxacin, spectinomycin, tetracycline, tiamuline, neomycin, chloramphenicol, kanamycin etc.