• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1583-1588
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• 2015

The large intestine is a home for trillions of microbiota, which confer many benefits on the host, including production of vitamins, absorption of nutrients, pathogen displacement, and development of the immune system. For several decades, germ-free animals have been used to study the interaction between the host and its microbiota. This minireview describes the technical aspects for establishing and maintaining germ-free animals and highlights the advantages and disadvantages for germ-free animals as experimental models.

• 한국발생생물학회지:발생과생식
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• 제26권4호
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• pp.145-153
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• 2022

The gut microbiota is involved in the maintenance of physiological homeostasis and is now recognized as a regulator of many diseases. Although germ-free mouse models are the standard for microbiome studies, mice with antibiotic-induced sterile intestines are often chosen as a fast and inexpensive alternative. Pathophysiological changes in the gut microbiome have been demonstrated, but there are no reports so far on how such alterations affect the bacterial composition of the uterus. Here we examined changes in uterine microbiota as a result of gut microbiome disruption in an antibiotics-based sterile-uterus mouse model. Sterility was induced in 6-week-old female mice by administration of a combination of antibiotics, and amplicons of a bacteria marker gene (16S rRNA) were sequenced to decipher bacterial community structures in the uterus. At the phylum-level, Proteobacteria, Firmicutes, and Actinobacteria were found to be dominant, while Ralstonia, Escherichia, and Prauserella were the major genera. Quantitative comparisons of the microbial contents of an antibiotic-fed and a control group revealed that the treatment resulted in the reduction of bacterial population density. Although there was no significant difference in bacterial community structures between the two animal groups, β-diversity analysis showed a converged profile of uterus microbiotain the germ-free model. These findings suggest that the induction of sterility does not result in changes in the levels of specific taxa but in a reduction of individual variations in the mouse uterus microbiota, accompanied by a decrease in overall bacterial population density.

• Molecules and Cells
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• 제37권6호
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• pp.473-479
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• 2014

Spermatogonial stem cells (SSCs, also called germline stem cells) are self-renewing unipotent stem cells that produce differentiating germ cells in the testis. SSCs can be isolated from the testis and cultured in vitro for long-term periods in the presence of feeder cells (often mouse embryonic fibroblasts). However, the maintenance of SSC feeder culture systems is tedious because preparation of feeder cells is needed at each subculture. In this study, we developed a Matrigel-based feeder-free culture system for long-term propagation of SSCs. Although several in vitro SSC culture systems without feeder cells have been previously described, our Matrigel-based feeder-free culture system is time- and cost-effective, and preserves self-renewability of SSCs. In addition, the growth rate of SSCs cultured using our newly developed system is equivalent to that in feeder cultures. We confirmed that the feeder-free cultured SSCs expressed germ cell markers both at the mRNA and protein levels. Furthermore, the functionality of feeder-free cultured SSCs was confirmed by their transplantation into germ cell-depleted mice. These results suggest that our newly developed feeder-free culture system provides a simple approach to maintaining SSCs in vitro and studying the basic biology of SSCs, including determination of their fate.

• 대한수의학회지
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• 제27권1호
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• pp.85-91
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• 1987

For the development of the specific pathogen free (SPF) or germ free laboratory animals, a parasitological survey was carried out and numerous pinworms were collected from the large intestines and caeca of the host animal Mus musculus alba. The pinworms collected from the laboratory albino mice were identified as Aspiculuris tetraptera, Syphacia muris and S. obvelata and classified into the Family Oxyuridae, Superfamily Oxyuroidea, Order Ascaridida. The overall infection rate of the pinworms was revealed as high as 64.8%(A. tetraptera 31.0%; S. muris 32.4% and S. obvelata 22.5%) consisting of the single species infection 47.9%, the double species infection 12.7% and the triple species infection 4.2%.

• 대한수의학회지
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• 제27권1호
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• pp.77-83
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• 1987

For the development of the specific pathogen free (SPF) or germ free laboratory animals, a parasitological approach was applied to the preliminarily selected laboratory albino mice (Mus musculus alba) in order to observe the ectoparasites on the hair of the host animal. The mites collected from the laboratory albino mice were identified as Myocoptes musculinus and classified into the Family Listrophoridae, Suborder Sarcoptiformes, Order Acarina. The overall infection rate of the mites was revealed as high as 73.2% (52 out of 71 heads) and the development process from the eggs to larvae was observed for the understanding of the basic ecological properties.

• 대한임상검사과학회지
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• 제47권4호
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• pp.161-167
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• 2015

정상인에서 장내세균은 숙주의 면역이나 영양 흡수를 돕지만, 때로는 기회감염균으로서 그들을 위협하기도 한다. 그 중 절대 혐기성 세균인 Bacteroides fragilis는 분비되는 장독소(enterotoxin)인 Bacteroides fragilis toxin (BFT)의 유무에 따라 non-enterotoxigenic B. fragilis (NTBF)와 enterotoxigenic B. fragilis (ETBF)로 나뉜다. ETBF는 가축 및 사람에서 설사 질환 및 대장 질환을 유발한다 그러나 때때로 ETBF를 가지고 있으나 증상이 없는 사람도 존재한다. ETBF는 염증성 설사 질환, 여행자 설사 환자의 대변에서 검출되어 주목 받고 있다. 또한, 몇몇 연구를 통해 inflammatory bowel disease (IBD)나 대장염 및 대장암 환자에서 ETBF가 증가한다는 것이 밝혀졌다. 일반 C57BL/6 마우스 및 germ-free 마우스, multiple intestinal neoplasia (Min) 마우스, 토끼, Mongolian gerbil 등 여러 동물 모델에서 ETBF가 IBD나 대장염, 대장암을 유발 또는 촉진한다는 것이 발표되었다. ETBF의 유일한 병원성 인자인 BFT는 E-cadherin의 분절을 유도하여 장상피 세포의 투과성을 높인다. 이어서 ${\beta}$-catenin 신호전달계가 활성화하여 장상피세포의 증식이 증가한다. 또한 ETBF의 감염은 일반 마우스에서 급성이나 만성의 대장염을 일으키고 Min 마우스에서 종양 형성을 촉진한다. 이는 Stat3에 의존한 $T_H17$ 면역반응의 활성화를 통해 일어난다. 현재 ETBF의 검출 방법에는 크게 BFT toxin assay와 몇 가지 PCR 방법이 있다. 최근 real-time PCR과 같은 분자진단학적 기법의 발달로 일반적인 PCR보다 더 정확한 ETBF의 검출이 가능하게 되었다. 이것을 이용하여 앞으로 실제 임상에서 ETBF와 대장염 및 대장암의 발달 관계에 대한 심도 깊은 연구가 이뤄질 것으로 본다.

• Radiation Oncology Journal
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• 제8권2호
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• pp.145-150
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• 1990

고환암에서 mesna는 ifosfamide와 병용 투여하면 요관 계통의 부작용을 방지할 수 있으며, adriamycin과 같이 사용하는 경우 항암제의 세포증식 억제능을 감소시키지 않으면서 부작용을 경감 시킨다. 방사선 보호제의 sulfhydryl가 방사선에 의하여 발생하는 hydroxyl 유리기와 반응하여 조직을 보호할 수 있고, 역시 체내에서 유리기를 발생하는 adriamycin의 독작용을 musua가 감소시키는 사실에 근거하여, 쥐에 mesna와 방사선을 투여하여 mesna의 방사선보호 작용을 관찰하였다. 본 연구에서는 방사선 단독 처치군과 mesna와 방사선 처치군에서 고환의 수정관 내의 배아세포의 수와 형태적 변화를 현미경 하에서 매주 비교하고 재생 능력의 차이를 확인하였다. 양쪽 군에서 공히 초기에 세포 수가 감소하고 후기에 다시 세포가 증식 하였으며, 가장 세포 수가 적게 관찰된 시기는 방사선 조사 후 3주 째였다. 모든 관찰 기간에서 mesna 처치군의 평균 배아 세포수가 방사선 단독 처치군보다 통계적으로 유의하게 많이 관찰되었고(p<0.05), 또한 mesna 처치군에서 더 유효한 세포 재생 능력이 있음이 관찰되었다. 이는 mesna가 방사선 상해로부터 고환의 수정관 내 배아세포를 보호하고 있음을 입증하는 것으로 사료된다. Mesna가 고환 이외의 다른 조직을 방사선으로부터 보호할 수 있는지의 여부와 종양의 관해율을 저해하지 않을지에 대하여는 더 이상의 연구가 필요할 것으로 생각된다.

• 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.