• 한국식품영양학회지
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• 제15권2호
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• pp.104-111
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• 2002

호열균 B. stearotheymophilus으로부터 단백질 고차구조 형성을 촉진하는 내열성 PPIase를 정제하기 위해, 이 균체를 대량으로 배양 집균, 파쇄하여 효소활성을 측정하였다. 효소의 활성측정은 N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide(pAN)를 기질로 사용하였다. chymotrypsin은 기질 이성체(cis-trans 형)의 한쪽(trans)만을 특이적으로 분해하는 반응을 이용하여 PPIase 활성을 측정하였다. 호열균 추출시료로 부터 효소활성을 확인한 후, DEAE-sepharose CL-6B, Sephadex G-75로 정제 후, 최종적으로 Superose TM-12 (FPLC) gel-필트레이션으로 분자량 18kDa의 본 효소를 정제하였다. 정제한 효소의 화학적 특징을 조사한 결과 pH 7.5~8.0사이에 안정하였으며, 최적 pH는 8.0으로 나타났다. 그리고 $65^{\circ}C$에 30분간 열처리 후, 효소활성을 측정한 결과 50%이상의 잔존 활성을 갖는 내열성 효소임을 확인하였다. 정제 단백질의 N-말단 아미노산 분석은 Edman 분해법으로 39 아미노산 잔기를 결정하였다. 그리고 PPIase의 재구성(refolding) 반응은, 요소로 변성시킨 기질 RNase 1을 이용하여 이 단백질의 재구성 (refolding) 실험을 조사한 결과, PPIase는 변성 기질 RNase 1의 재구성(refolding)을 촉진하는데 높은 효과를 가지고 있었다. 호열균 유전자 라이브러리로부터 PPIase 유전자 약 3kb을 클로닝하였다. 재조합 플라스미드 cPI-40에서 프라이머(A-1, B-2)를 이용하여 PPIase N-말단을 코드하는 유전자를 PCR법으로 증폭하여, 염기배열을 결정한 결과 증폭된 단편은 165염기로 형성된 55 아미노산 잔기를 코드하는 open reading frame(ORF)가 연속되고 있었다. 그리고 Edman법으로 결정한 PPIase의 39아미노산 잔기가 이 배열내에 완전히 보존되어 있었다. 이 결과로부터 이 ORF는PPIase구조 유전자의 1/3에 해당하는 단편임을 확인하였다.

• 미생물학회지
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• 제29권5호
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• pp.290-295
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• 1991

N4 phage, which infects E. coli K-12 strains, could not infect E. coli K-12 strains containing rtn(resistant to N4) gene on plasmids, which was isolated from Proteus vulgaris ATCC 13315. The region of rtn gene for Rtn phenotype was reduced to the 1.7 kb HincII-AccI fragment, and rtn gene seemed to have its own promoter. This putative promoter was present in 107 bp HindII-DraI fragment, and known to be functional in E. cole K-12, which is supported by the fact that phenotype of a subclone, pRMG103A1B which does not contain the 107 bp fragment, was dependent on the existance of a functional promoter in the upstream of rtn gene, and that the 107 bp fragment had promoter activity when located in the upstream of structural gene of galactodinase of E. coli. The promoter-bearing fragment contains two overlapping putative promoter sequences, both of which show a fit in eight of twelve nucleotides with consensus sequences of E. coli promoters at the -35 and -10 regions.

• Applied Biological Chemistry
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• 제51권4호
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• pp.299-304
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• 2008

A ${\beta}$-1,4-endoglucanase gene from Bacillus subtilis H12 was cloned into Escherichia coli JM109 (pBC8) and sequenced. The endoglucanase gene with an insert DNA of 2.5 kb possessed an open reading frame of 1,500 bp encoding a mature protein of 499 amino acids with a calculated molecular mass of 55 kDa. The deduced amino acid sequence showed similarity to those of the known neutral cellulase genes of B. subtilis PAP115 (99.2%) and BSE616 (97.8%), as well as the alkaline gene of Bacillus sp. N4 (55.1%). The endoglucanase activity expressed by E. coli (pBC8) was localized in the periplasmic fraction (80%) and the cytoplasmic fraction (20%). An endoglucanase was purified from the periplasmic fraction by performing gel filtration and anion exchange chromatography. The molecular weight of the purified enzyme was estimated to be 31 kDa by SDS-PAGE, and the maximum activity occurred at pH 7 and $40^{\circ}C$. The enzyme easily hydrolyzed soluble substrates such as carboxymethyl cellulose and barely ${\beta}$-glucan, whereas the sigmacell and xylan, the known insoluble substrates, were not entirely hydrolyzed.

• 대한수의학회지
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• 제46권4호
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• pp.337-345
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• 2006

The shigellae are common etiological agents of bacillary dysentery in humans and primates. During four years from 2002 to 2005, 22 strains of Shigella spp. were isolated from the diarrheic patients in Seoul region. All of them were identified as S. flexneri by biochemical tests and serotyping. The prevalence of serotypes were variable by year, but the major serotypes were 2a and 3a. In an antimicrobial susceptibility test, all of the isolates were resistant to streptomycin and tetracycline, and susceptible to amikacin, kanamycin, cefoxitin, and gentamicin. All of the isolates showed the multi-resistant patterns over 3 drugs. By analysis of the plasmid profile the isolates were classified into 7 groups (P1~P7). Serotypes 2a and 2b were distributed to P1, P2, P3, and P4. Serotype 3a was differentiated to P5 and serotype 3b, to P6 and serotype 4a, to P7. PCR results showed that all isolates were positive for two virulence genes, ipaH and ial, but none of the strains had stx gene. The set1A and set1B genes were detected from 12 isolates (54.5%) that belonged to serotype 2a and 2b. The sen gene was detected from 19 isolates (86.4%). The 22 isolates showed 12 to 17 DNA fragments in the sizes ranging from 20.5 kb to 1135 kb, resulting in 13 patterns by the PFGE with Not I digestion. The PFGE patterns of the isolates showed the close relation with the serotypes, but no relations with year of isolation and antimicrobial resistance.

• 한국초지조사료학회지
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• 제32권3호
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• pp.229-236
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• 2012

본 시험은 2010년부터 2012년까지 3년동안 경북 성주 계명문화대학 실험목장에서 이탈리안 라이그라스 품종의 생육특성 및 건물수량을 평가하기 위하여 실시하였다. 시험설계는 조중생종은 품종을 처리로 12처리 3반복, 중만생품종은 품종을 처리로 10처리 3반복 난괴법으로 배치하였다. 1년차 시험은 2010년 10월 12일에 파종하여 조중생종은 2011년 4월 29일, 중만생종은 동년 5월 4일에 수확하였고, 2년차시험은 2011년 10월 3일에 파종하여 조중생품종은 2012년 5월 5일 중만생종은 동년 5월 12일에 수확하였다. 조중생 품종의 건물수량은 Yeonbong3, Seongnong, Winter Hawk, Pride 및 Kowinnearly 품종이 각각 9,850, 9,778, 9,486, 9,363 및 9,267 kg/ha 순위였으며 이들 품종 간에 수량 차이는 없었으나 다른 7품종 보다 높았다(p<0.05). 중만생 품종의 건물수량은 Tetragold, Hwasan 101, Jumbo, Sungrazer, Master, SelectIV 및 KB Royal이 각각 9,542, 9,492, 9,103, 8,981, 8,903, 8,870 및 8,681 kg/ha 순위였으며 이들 품종 간에 수량 차이는 없었으나, 다른 3품종 보다는 높았다(p<0.05). 내한성은 중만생 품종중에서 Hwasan 101가 다른 품종보다 높은 경향을 보였다. 본 시험의 결과에 의하면 조기수확 시 건물수량 측면에서 조중생 품종이 유리할 것으로 생각된다.

• 대한소아치과학회지
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• 제27권2호
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• pp.361-369
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• 2000

장구균은 사람의 구강, 질, 장내 등에 정상적으로 존재하는 세균이다. 본 연구에서는 구강에서 분리된 장구균중 Enterococcus durans로 동정된 분리균주 4주의 특성과 구강내 주요 세균인 Streptococcus mutans와 Streptococcus oralis와의 관계를 연구하여 다음과 같은 결과를 얻었다. 1. 분리균주에 대한 당 발효 검사와 생화학적 검사 결과, 비슷한 양상을 보였다. 2. 분리균주 모두 erythromycin, penicillin, tobramycin, ampicillin, teicoplanin, ciprofloxacin, vancomycin. gentamicin, kanamycin 및 streptomycin에 대해 감수성을 보였다. 3. S. mutans를 일회용 큐벧에서 단독 배양시 550 nm에서의 흡광도가 1.405이었으나. S. mutans와 4주의 분리균주 혼합 배양시에는 각각의 흡광도가 0.855, 0.867, 0.797, 1.083으로 감소되었다. 4. 비커 와이어 검사 결과, S. mutans 단독 배양시 형성된 인공치태의 평균 무게는 $1566{\pm}103mg$이었다. S. mutans와 4주의 분리균주 혼합 배양시에는 각각 $44{\pm}5mg,\;41{\pm}12mg,\;34{\pm}7mg,\;38{\pm}12mg$으로 현저히 감소되었다. 배양후 생균수는 S. mutans 단독 배양시 ml당 $2.0\times10^9$ 이었으나, S. mutans와 4주의 분리균주 혼합 배양시 S. mutans는 $2.0\times10^7$ 내지 $6.0\times10^7$으로 감소되었다. 5. S. oralis 단독 배양시 ml당 $2.1\times10^8$ 이었으나, S. oralis와 4주의 분리균주 혼합 배양시 S. oralis는 $1.4\times10^7$ 내지 $7.0\times10^7$으로 감소되었다. 6. 3주의 분리균주로 부터 약 60 kb의 plasmid를 분리 할 수 있었다. 이상의 결과를 종합하면 구강에서 분리된 E. durans는 S. mutans의 증식을 억제하여 인공치태 형성을 저지하였고, S. oralis의 증식은 약간 억제하였다.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.368-372
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• 1994

Three more unusual macrolides in addition to concnamycin B were isolated from the mycelium of Streptomyces sp. strain Bal6. These four compounds showed a potent cytotoxity to hunian cancer cell lines, SNU-1 (stomach cancer cell line), SNU-354 (liver cancer cell line), MCF- 7 (breast cancer cell line) and KB-3-1 (oral epidermoid carcinoma cell line). Interestingly, these compounds confered slight differential cytotoxity on RHEK-1, a human epidermal keratinocyte cell line immotalized by AD12-SV40 hybrid virus and RHEK-1/pSV$_{2}$ ras which was resulted from H-ras transfomation of RHEK-1. These compounds were determined to be concanamycin A, conca- namycin E and 0-methyl concanamycin B by NMR and other spectral analysis.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2224-2227
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• 2016

Shigella sonnei harboring $bla_{CTX-M-55}$ was isolated outside of Asia for the first time. The $bla_{CTX-M-55}$ gene was found to be downstream of ISEcp-1 and located in a ~130 kb conjugative plasmid belonging to the I1 incompatibility group. The strain was recovered from a 7-year-old Ecuadorian girl with watery diarrhea who had not travelled abroad. Recent local data describe the emergence of $bla_{CTX-M-55}$ and other variants typically found in Asia in the Andean Region, suggesting that increased travel of humans and trade relationships with Asian countries are influencing the current Ecuadorian bacterial resistance situation.

• Journal of Microbiology
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• 제34권1호
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• pp.1-6
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• 1996

The nucleic acid of Synechococcus sp. cyanophage was identified as double-stranded DNA by the result of digestion with enzymes such as exonucleases, DNase, and S1 nuclease, and by acridine orange staining. The cyanophage DNA was cleaved with several restriciton ehdonucleases such as ApaI, BamHI, Bg/II, HaeIII, Eco RI, HindIII, PstI, AND aPAI gave the clearest sets of bands on agarose gels and the fragment numbers for each were 12, 20, 29, 20, and 7, respectively. The sums of the size from Bam HI and PstI digestions were estimated approximately 227$\pm$4 kb, which are in agreement with the result of the pulsed field gel electrphoresis. This virus is thought to have the largest genosome among those of known cyanophages, which corresponds to the largest haed ot 90 nm when compared with the head sizes of cyanophages discovered since 1963.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.7-12
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• 2001

Three Pseudomonas strains (Bk8, Bk9, Bk10) selected from soil for their ability to degrade herbicide diuron were tested for their heavy metal resistance. The growth of these catabolic strains on a minimal medium with various concentrations of $Cd^{2+},\;Zn^{2+},\;Ni^{2+}$, and $Hg^{2+}$ revealed a minimal effect on the carbon source for the inhibitory effect of the metals. One of these strains, namely, Bk8, exhibited a high resistance to the heavy metals as compared to the two other strains. This strain harbors plasmid pBk8 (110 kb) and contains at least fur determinants encoding heavy metal resistance. Nickel and zinc resistance are encoded by genes located on the chromosome, while cadmium and mercury resistance are on plasmid pBk8. Accordingly, the characteristics of strain Bk8 suggest that it would be useful in the bioremediation of aromatic compounds in the presence of toxic heavy metals as co-contaminants.