• 대한수의학회지
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• 제38권4호
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• pp.745-750
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• 1998

A sensitive and rapid enzyme immunoassay(EIA) to detect Escherichia coli O157 in ground beef was developed by using a sandwich type assay with polyclonal antibodies to E coli O157. E coli O157 in ground beef could be detected within 15hr, including incubation for 12hr in enrichment broth and 3hr in immunoassay. The EIA could detect $1.3{\times}10^5$ cells of E coli O157/g of ground beef without enrichment. The lowest limit of detection was 0.23 E coli O157 per g of meat after enrichment. Confirmation was required in the positive specimens in the EIA by culture method even though the negative specimens were not. These results suggested that the immunoassay could be a very efficient method for the screening E coli O157 in meat.

• 미생물학회지
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• 제30권6호
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• pp.501-506
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• 1992

An alkalophilic Vibrio sp. RH530 showing high proteolytic activity was isolated form soil samples by enrichment culture. The activity staining using gelatin SDS- polyacrylamide gel electrophoresis (PAGE ) revealed that the strain produced an alkaline major protease (Apr B) with a size of 27 kDa, and at least six minor proteases. The apparent sizes of four of the minor proteases were approximately 45, 28, 22 and 19 kDa. Apr B and five of the minor proteases were inhibited by serine protease inhibitors including PMSF and DFP, suggesting that they are serine proteases. One of the minor proteases was inhibited by metalloprotease inhibitors, not by serine protease inhibitors, indicating it to be a metalloprotease. Furthermore, the activities of Apr B and Prt 3 were not inhibited by SDS in the reaction mixture. The production of Apr B and some of the minor proteases was specifically affected by culture temperature (30 to 37.deg.C) and pH (7 to 10). The production of Apr B. Prt 2, Prt 5 and Prt 6 was mainly affected by culture temperature, while Prt 4 by culture pH. Prt 1 and Prt 3 were not affected by neither of these factors.

• Asian-Australasian Journal of Animal Sciences
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• 제22권2호
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• pp.187-193
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• 2009

The present study identified the favorable conditions for isolation, enrichment and in vitro culture of highly purified, undifferentiated pig spermatogonial stem cell (SSC) lines that proliferate for long periods of time in culture. The colonies displayed morphology similar to miceSSC and were positive for markers of SSC (PGP9.5), proliferating germ cell (PigVASA), pre-meiotic germ cell (DAZL) and pluripotency (OCT4, SSEA-1, NANOG, and SOX2) based on immuno-cytochemistry and RT-PCR. The purity of these colonies was confirmed by negative expression of markers for sertoli cell (GATA4 and SOX9), peritubular myoid cell (${\alpha}$-SMA), differentiating spermatogonial and germ cells (c-KIT). The colonies could be maintained with undifferentiated morphology for more than two months and passaged more than 8 times with doubling time between 6-7 days. Taken together, we conclude that pigSSC could be successfully isolated and cultured in vitro and they possess characteristics similar to miceSSC.

• Restorative Dentistry and Endodontics
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• 제37권3호
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• pp.142-148
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• 2012

Objectives: We analyzed gene-expression profiles after 14 day odontogenic induction of human dental pulp cells (DPCs) using a DNA microarray and sought candidate genes possibly associated with mineralization. Materials and Methods: Induced human dental pulp cells were obtained by culturing DPCs in odontogenic induction medium (OM) for 14 day. Cells exposed to normal culture medium were used as controls. Total RNA was extracted from cells and analyzed by microarray analysis and the key results were confirmed selectively by reverse-transcriptase polymerase chain reaction (RT-PCR). We also performed a gene set enrichment analysis (GSEA) of the microarray data. Results: Six hundred and five genes among the 47,320 probes on the BeadChip differed by a factor of more than two-fold in the induced cells. Of these, 217 genes were upregulated, and 388 were down-regulated. GSEA revealed that in the induced cells, genes implicated in Apoptosis and Signaling by wingless MMTV integration (Wnt) were significantly upregulated. Conclusions: Genes implicated in Apoptosis and Signaling by Wnt are highly connected to the differentiation of dental pulp cells into odontoblast.

• 대한수의학회지
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• 제38권3호
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• pp.559-564
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• 1998

The polymerase chain reaction(PCR) assay was used for rapid diagnosis from blood and organ samples experimentally infected with Listeria monocytogenes. This method used a pair of primers based on a unique region in the 16S rRNA sequence of L monocytogenes. Procedure A was based on dilution of the blood sample followed by lysis of bacterial cell and direct analysis of the lysate with PCR. In artificially infected blood samples with L monocytogenes, it was possible to detect fewer than 40 cells per ml of blood. However, L monocytogenes was detected low rates on infected organs by the direct PCR. In procedure B, enrichment cultivation was used to increase numbers of bacteria before lysis and PCR. L monocytogenes was detected from 23 samples of 24 liver and spleen, respectively, and 18 samples of 24 blood were found to be positive by PCR on a subset of 72 organ samples, whereas L monocytogenes were detected on 63 organ samples in classical culture technique. It was required to analyze including enrichment steps were 6h and 18h on the procedure A and B, respectively.

• 한국환경농학회지
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• 제27권3호
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• pp.292-297
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• 2008

우리나라에서 유일하게 사용되고 있는 유기염소계 살충제 endosulfan을 미생물학적 방법으로 분해하기 위하여 총 182점의 토양, 퇴비 및 액상의 미생물 시료를 접종원으로 실시한 endosulfan 집식(enrichment) 실험으로부터 endosulfan을 endosulfan diol 형태로 경유하여 분해하는 균주를 선발하고 그 이름을 Bacillus sp. E64-2로 명명하였다. 분리균주는 7일만에 배지에 함유된 10 mg/L 농도의 endosulfan을 99% 이상 분해하였다. 또한 분리균주 Bacillus sp. E64-2의 조효소액은 endosulfan을 endosulfan diol로 전환하는 활성을 가지고 있었으며 균주 자체는 생육 중에 배지의 pH를 배양 7일 만에 pH 7.0에서 pH 8.4로 올릴 수 있었다. 이러한 효소활성과 pH 증가 능력은 분리균주 E64-2에 의한 endosulfan 분해의 주된 작용 인자인 것으로 판단되며 이 균주는 효소에 의한 분해작용과 pH 상승작용을 통하여 토양에 잔류는 난분해성 물질인 endosulfan을 bioremediation하기 위한 연구의 기초 균주로서의 가치가있을 것으로 판단된다.

• KSBB Journal
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• 제8권2호
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• pp.156-163
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• 1993

Polyester 감량폐수의 주성분인 EG,TPA분해균을 분리하여 각각 Pseudomonas sp.로 동정하여 Pseudomonas sp. EAW, Pseudomonas sp. TS2로 명명하였다. 이 두 균주의 최적 배양조건은 pH 7.5, 온도 $35^{\circ}C$ 및 질소원은 ${(NH_4)}_2SO_4$ 이며, Strain EAW의 경우 niacin과 biotin, Strain TS2의 경우 $Na_2MoO_4{\cdot}2H_2O$와 thiamine이 각 균주의 성장과 분해율에 약간씩 영향을 미치는 것으로 나타났다. Strain EAW는 접종량의 증가에 따라서 성장 및 EG의 분해시간이 현저히 감소하였으나 Strain TS2의 경우는 접종량이 증가하여도 성장 및 분해율이 큰 차이가 없었다. 또한 rich-medium에 계대배양한 각 균을 EG, T TPA액체배지에 접종하였을 때 계대배양의 회수가 증가함에 따라 Strain EAW가 Strain TS2보다 성장 및 분해율이 현저히 감소하였다. 실제 폐수에서 균들의 성장 및 분해율이 분리용 배지의 경우 보다는 약간 감소하였으며 EG, TPA 는 배양 48hr 후 $COD_{Mn}\;and\;COD_{Cr}$의 제거율은 89% 와 93%로 각각 나타났다. 회분배양시 EG,TPA의 초기농도가 25g/L 이상에서는 각 균주의 비성장속도가 감소하였다.

• 한국미생물·생명공학회지
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• 제17권4호
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• pp.321-326
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• 1989

m-Toluate 최소배지에서 선택적 enrichment culture를 통하여 82개의 세균의 균주를 분리하였으며, ol들 중 두 균주는 Pseudomonas cepacia, 한 균주는 P. Putida, 한 균주는 Yersinia intermedia, 그리고 한 균주는 Flavobacterium odoratum으로 동정되었다. P. cepacia SUB37은 P. putida mt-2의 TOL 플라스미드와 비슷한 크기의 플라스미드를 가지고 있었으며, Flavobacterium odoratum과 Yersinia intermedia는 이보다 더 큰 플라스미드를 갖고 있었다. P. cepacia SUB37은 streptomycin에 감수성을 나타내었으나, rifampicin에는 내성을 나타내었다. 플라스미드를 갖는 P. cepacia SUB37은 탄화수소를 해당 알콜과 알데히드를 거쳐서 benzoate와 toluate 로 분해하였다. 플라스미드 제거실험으로, P. Cepacia SUB37의 플라스미드에는 탄화수소 분해과정 중 toluene과 xylene을 benzoate, toluate로 분해하는 효소와, 계속하여 meta pathway를 거치는 단계의 효소를 코딩하는 유전자들이 있음이 확인되었다. 또한 P. cepacia SUB37은 생장이 왕성하였을 때 m-toluate를 거의 분해하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권4호
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• pp.299-305
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• 2006

Aromatic L-amino acid transaminase is an enzyme that is able to transfer the amino group from L-glutamate to unnatural aromatic ${\alpha}-keto$ acids to generate ${\alpha}-ketoglutarate$ and unnatural aromatic L-amino acids, respectively. Enrichment culture was used to isolate thermophilic Bacillus sp. T30 expressing this enzyme for use in the synthesis of unnatural L-amino acids. The asymmetric syntheses of L-homophenylalanine and L-phenylglycine resulted in conversion yields of >95% and >93% from 150 mM 2-oxo-4-phenylbutyrate and phenylglyoxylate, respectively, using L-glutamate as an amino donor at $60^{\circ}C$. Synthesized L-homophenylalanine and L-phenylglycine were optically pure (>99% enantiomeric excess) and continuously pre-cipitated in the reaction solution due to their low solubility at the given reaction pH. While the solubility of the ${\alpha}-keto$ acid substrates is dependent on temperature, the solubility of the unnatural L-amino acid products is dependent on the reaction pH. As the solubility difference between substrate and product at the given reaction pH is therefore larger at higher temperature, the thermophilic transaminase was successfully used to shift the reaction equilibrium toward rapid product formation.

• 한국미생물·생명공학회지
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• 제2권1호
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• pp.1-7
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• 1974

농산페자원을 기질로 하여 섬유소단세포단백을 생산하기 위해 전국에서 수집한 썩은 나무, 퇴비, 토양 등 시료에서 enrichment culture technique으로 172주의 섬유소자화세균을 분리하였다. 이들중 섬유소 자화력이 강한 균 6주를 동정하여 다음 결과를 얻었다. 1. 선별한 6주 중 5주는 Cellulomonas속이었으며 나머지 1주는 Sporocytophaga속이었다. 2. Sporocytophaga속의 세균은 microcyst가 타원형인 S. ellepsospora이었다. 3. Cellulomonas속의 세균들은 C.fimi 1균주, C.gelida 1균주, C. flavigena 2균주 및 C. aurogena 1 균주이 었다. 4. 분리균 C. aurogena는 5탄당인 arabinose 와 xylose를 자화하는 성질이 Bergey's Manual에 수록된 균과 달라 새로운 변종으로 판명되었다.