• Journal of Microbiology and Biotechnology
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• 제4권1호
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• pp.1-6
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• 1994

Continuous culture was carried out with a recombinant Escherichia coli W3110/pCR185, which encodes trp-operon enzymes when the temperature is shifted from $37^{circ}C\;t;42^{\circ}C$. Under derepressed condition of $42^{\circ}C$. plasmlid stability and gene expression were analysed as function of the dilution rate. The stability of plasmid increased with the dilution rate, but maximal levels of gene expression (tryptophan concentration) and plasmid DNA content were obtained at the lowest dilution rate, $0.075\;hr^{-1}$. The plasmid instability, observed at low dilution rates, could be explained by the unbalanced biosynthetic state of the recombinant cell harboring a high copy number of plasmid.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.796-801
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• 2011

Corynebacterium tuberculostearicum B146, a strain derived from healthy human skin, contains a medium copy plasmid, p1B146. This plasmid was cloned and its complete nucleotide sequence determined. As a result, p1B146 was found to be 4,2 kb in size with a 53% G+C content, plus six open reading frames (ORFs) were distinguished. According to a computer-assisted alignment, two of the ORFs exhibited significant similarities to already-known common plasmid proteins, the first being the RepA gene, responsible for plasmid replication via a rolling-circle mechanism, and the second being an FtsK-like protein, the function of which remains unclear. The presence and quantity of RNA fragments in the putative ORFs were also evaluated.

• 산업기술연구
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• 제28권B호
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• pp.53-57
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• 2008

From the extensive screening for small cryptic plasmid among about 23 lactic acid bacteria (LAB), 2.4 kb of cryptic plasmid was isolated from Lactobacillus farciminis strain KCTC 3681 and named as pLF24. The plasmid pLF24 was a circular molecule of 2,396 base-pairs in length with a G+C content of 38%. Two protein-coding sequences could be predicted. ORF1 and ORF2 showed homologies to plasmids of gram-positive bacteria. The replication protein coded by ORF2 and the plus origin, were similar to replication regions of other gram-positive bacteria as shown in plasmids such as pLH2, pLS141-1 and pLC2. The nucleotide sequence of pLF24 was deposited into Genbank data base with an accession number of EU429343. The newly isolated plasmid can be used for construction of shuttle vector in Lactobacillus bacteria.

• 미생물학회지
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• 제53권3호
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• pp.216-218
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• 2017

생물학적방제 효과가 뛰어난 Bacillus thuringiensis C25 균주의 유전체 분석을 수행하였다. 본 균주는 5,308,062 bp, G+C 비율 35.32%의 염색체와 308,946 bp, 32.23% G+C 함량이 포함된 plasmid를 지닌 것으로 확인되었다. 염색체와 plasmid DNA에 예측된 유전자의 총 수는 5,683개의 단백질 코딩유전자와 107개 tRNA 그리고 42개의 rRNA였다.

• Journal of Microbiology and Biotechnology
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• 제13권3호
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• pp.457-462
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• 2003

The complete nucleotide sequence of a plasmid, pMG1, isolated from Bifidobacterium longum MG1 has been determined. This plasmid, composed of 3,862 base pairs with 65.1% of G+C content. harbors two major open reading frames (ORF) encoding putative proteins of 29 kDa (ORF I) and 71 kDa (ORF II). ORF I showed relatively high amino acid sequence homology with replication proteins of other plasmids from Gr Im-positive and -negative bacteria. Upstream of ORF I, four sets of tandem repeat sequences resembling the iteron structure of related plasmids were found. S1 endonuclease treatment and Southern blot analysis revealed that pMG1 accumulates single-stranded DNA (ssDNA) intermediate, which indicate i the rolling circle replication (RCR) mechanism of this plasmid. Homology search indicated that ORF II encodes plasmid mobilization protein, and the presence of highly conserved oriT sequence in the upstream of this gene supported this assumption. RT-PCR showed that only ORF I is expressed in vivo. Based on these results, pMG 1 was exploited to construct a shuttle vector, pBES2. It was successfully transformed into Bifidobacterium and maintained stably.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.403-408
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• 2009

A number of bifidobacterial species of human origin were screened for the presence of cryptic plasmids. One strain, Bifidobacterium longum FI10564, harbored plasmids of approximately 2.2 kb, 3.6 kb, and 4.9 kb in size. The smallest plasmid, pFI2576(2,197 bp), was studied in detail and its complete nucleotide sequence was determined. Computer-assisted analysis of this novel plasmid(G+C content 62%) identified 9 putative open reading frames(orfs), 3 of which were shown to be probable genes. These putative genes are arranged in an operon-like structure, in which the overlapping orfs 1 and 2 encode putative Rep proteins and are highly homologous to the rep genes of the B. longum plasmid pMBI(1,847 bp). The mechanism of replication of pFI2576 was investigated using Southern blot analysis of whole cell lysates, with and without S1 nuclease treatment, and atomic force microscopy(AFM). The results indicate that pFI2576 is likely to use the theta mode of replication.

• 대한수의학회지
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• 제48권4호
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• pp.441-449
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• 2008

The genus Lactobacillus is the largest of the genera included in lactic acid bacteria and is associated with mucosal membranes of human and animal. Only a few Lactobacillus plasmid-encoded functions have been discovered and used. In this study, a novel plasmid (pILR091) was isolated from a wild L. reuteri isolated from pig and described the characteristics of its replicons, genetic organization, and relationship with other plasmids. After digestion of the plasmid, pILR091, with SalI, plasmid DNA was cloned into the pQE-30Xa vector and sequenced. The complete sequence was confirmed by the sequencing of PCR products and analyzed with the Genbank database. The isolate copy number and stability were determined by quantitative-PCR. The complete sequence of L. reuteri contained 7,185 nucleotides with 39% G-C content and one cut site by two enzymes, SalI and HindIII. The similar ori sequence of the pC194- rolling circle replication family (TTTATATTGAT) was located 63 bp upstream of the protein replication sequence, ORF 1. Total of five ORFs was identified and the coding sequence represented 4,966 nucleotides (70.4%). ORF1 of pILR091 had a low similarity with the sequence of pTE44. Other ORFs also showed low homology and E-values. The average G-C content of pILR091 was 39%, similar with that of genomic DNA. The copy number of pILR091 was determined at approximately 24 to 25 molecules per genomic DNA. These results suggested that pILR091 might be a good candidate to construct a new vector, which could be used for cloning and expression of foreign genes in lactobacilli.

• 미생물학회지
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• 제52권3호
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• pp.254-259
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• 2016

시드로포어인 2, 3-dihydroxybenzoic acid (DHB)를 생산하는 Acinetobacter sp. B-W의 플라스미드를 분석한 결과, 20 kb 크기의 플라스미드를 함유하였다. 배양 온도 $43^{\circ}C$ 가 플라스미드가 제거된 돌연변이체 생산에 효과적이었다. 이 돌연변이체는 2,3-DHB 생산 능력을 소실하였으며, chrome azurol S (CAS) 아가 배지에서 시드로포어 생산이 검출되지 않았다. 포도당과 황산 망간을 함유한 배지에서 $28^{\circ}C$로 3일간 배양한 B-W 원 균주와 돌연변이체의 배양 상등액의 pH는 각각 4.5와 8.5로 나타났다. 돌연변이체에서는 ampicillin, actinomycin D, bacitracin, lincomycin과 vancomycin 같은 항생제에 대한 저항성이 사라졌으며, 이러한 항생제에 대한 최소 억제 농도(MIC)가 급격하게 감소하였다. B-W 균주에서 분리한 플라스미드로 대장균을 형질전환시킨 결과, 원 균주와 같은 크기의 플라스미드가 이 형질전환 대장균에서 발견되었다. 플라스미드가 제거된 돌연변이체에서는 플라스미드가 발견되지 않았다. 20 kb 크기의 플라스미드에 2,3-DHB 생산 유전자와 여러 항생제 저항성 유전자가 자리잡고 있는 것으로 추정된다.

• 대한미생물학회지
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• 제34권6호
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• pp.513-518
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• 1999

A total of 113 Vibrio sp. strains were examined for plasmid content which were subjected to digestion with restriction enzymes. About the 55% Vibrio spp. have the plasmid more than one. Most of these plasmid various derivatives ranged from $2.4\;kb{\sim}23\;kb$, especially two strains of V. mimicus and one strain of V. furnissii carried one high-molecular weight plasmid (molecular weight ranging between $70\;kb{\sim}100\;kb$). Results of restriction analysis for plasmid of this three strains were by no means the rule. For detection of tdh and ctx gene, the virulence factor involved in the pathogenesis, we carried out the TDH and CT assay, PCR amplification, and hybridization. A total 11 strains were produced TDH, involved in 9 strains of V. parahaemolyticus and 1 strain of V. alginolyticus from clinical isolates and 1 strains of V. mimicus from environmental isolates. In the experiments of tdh gene detection, in all, 3 strains of V. parahaemolyticus from clinical isolates and 2 strains from environmental isolates could be successfully amplified in 400 bp by PCR. The PCR results were consistent with DNA hybridization tests. In the experiments of CT assay, in all, 3 strains of V. cholerae from clinical isolate and 1 strain of V. cholerae from environmental isolates were observed CT-producing. These CT-producing strains amplified in 302 bp by PCR for the detection of ctx gene. All CT-producing strains hybridized with digoxigenin-labeled DNA probe, while CT-negative strains did not hybridize. Also hybridization tests results for detection of ctx gene consistent with PCR.

• Journal of Animal Science and Technology
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• 제62권3호
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• pp.423-426
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• 2020

Staphylococcus aureus is a significant pathogen that can source a variety of illness worldwide. In this announcement, we report here the complete genome sequence of S. aureus strain JDFM SA01, isolated from a milk filter collected from Korean dairy farm. The final complete genome assembly consists of one circular chromosome (2,748,925 bp) with an overall GC content of 32.9% and one circular plasmid sequence (24,655bp) with a GC content of 28.7%.