• Genomics & Informatics
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• v.1 no.1
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• pp.55-60
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• 2003

The nucleotide sequence of pZMO1, a small cryptic plasmid of Zymomonas mobilis ATCC10988 was determined. Analysis of 1,680 bp of sequence revealed $69\%$ identity with Shigella sonnei plasmid, pKYM and $61\%$ identity with Nostoc sp. ss DNA replicating plasmid. Analysis of a deduced amino acid sequence of an orf of pZMO1 revealed $75\%$ identity and $90\%$ similarity with the repA gene of Synechocystis sp. plasmid pCA2.4. The upstream region of the repA gene of pZMO1 possesses six directed repeat sequences and two inverted repeat sequences at downstream of the IR consensus sequence of nick region of rolling circle replication (RCR) plasmid. A typical terminator hairpin structure was found at the downstream region of repA gene. Degradation of single-stranded plasmid DNA by S1 nuclease was detected by Southern hybridization. It suggests that pZMO1 replicates by a rolling circle mechanism in Z. mobilis ATCC10988 cells.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.44-47
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• 1993

A replication initiation gene was identified and its nucleotide sequence has been determined from a 3.8 kb, chloramphenicol acethyltransferase conferring R-plasmid pSBK203 of Staphylococcus aures. Location of the replication related region of pSBK 203 was determined by interuption with pUC 119 at XBaI and MspI sites which resulted in inactivation of replication in Bacilius subtilis. Base sequence of this region revealed on open reading frame of 942 base pairs, which encoded a 314 amino acid protein. Base sequence homology with other rep of pT181 family plasmids such as pT181, pC221, pC223, pS194, pU112, and pCW7 was ranged from 78% to 97% and the predicted amino acid sequence homology was from 72% to 95%.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1778-1782
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• 2017

To identify and discriminate the bacterial species at the subspecific level, rep-PCR is a reliable genomic fingerprinting tool. Fourteen strains of bacteria were isolated from different food sources, identified as Leuconostoc citreum using 16S rRNA gene sequencing, and amplified using rep-primers (REP, ERIC, and $(GTG)_5$). Fingerprinting patterns generated bands in the range of 300-6,000 bp with REP, 150-6,000 bp with ERIC, and 200-1,700 bp with $(GTG)_5$ primers. In UPGMA dendrogram analysis, 14 strains were clustered into three clades (I, II, and III) with all the primers, thus differentiating them at the molecular level. The present study revealed the differentiation of L. citreum strains using rep-PCR.

• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1841-1847
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• 2007

We previously identified the origin of replication of p703/5, a small cryptic plasmid from the KBL703 strain of Enterococcus faecalis. The origin of replication contains putative regulatory cis-elements required for replication and a replication initiator (RepA) gene. The replicon of p703/5 is similar in its structural organization to theta-type plasmids, and RepA is homologous to a family of Rep proteins identified in several plasmids from Gram-positive bacteria. Here, we report molecular interactions between RepA and the replication origin of p703/5. DNase I footprinting using recombinant RepA together with electrophoretic mobility shift assays confirmed the binding of RepA to the replication origin of p703/5 via iterons and an inverted repeat. We also demonstrated the formation of RepA dimers and the different binding of RepA to the iteron and the inverted repeat using gel filtration chromatographic analysis, a chemical crosslinking assay, and electrophoretic mobility shift assays in the presence of guanidine hydrochloride. Our results suggest that RepA plays a regulatory role in the replication of the enterococcal plasmid p703/5 via mechanisms similar to those of typical iteroncarrying theta-type plasmids.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1101-1108
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• 2011

The rise in global energy demand has prompted researches on developing strategies for transforming coal into a cleaner fuel. This requires isolation of microbes with the capability to degrade complex coal into simpler substrates to support methanogenesis in the coal beds. In this study, aerobic bacteria were isolated from an Indian coal bed that can solubilize and utilize coal as the sole source of carbon. The six bacterial isolates capable of growing on coal agar medium were identified on the basis of their 16S rRNA gene sequences, which clustered into two groups; Group I isolates belonged to the genus Rhizobium, whereas Group II isolates were identified as Chelatococcus species. Out of the 4 methods of whole genome fingerprinting (ERIC-PCR, REP-PCR, BOX-PCR, and RAPD), REP-PCR showed maximum differentiation among strains within each group. Only Chelatococcus strains showed the ability to solubilize and utilize coal as the sole source of carbon. On the basis of 16S rRNA gene sequence and the ability to utilize different carbon sources, the Chelatococcus strains showed maximum similarity to C. daeguensis. This is the first report showing occurrence of Rhizobium and Chelatococcus strains in an Indian coal bed, and the ability of Chelatococcus isolates to solubilize and utilize coal as a sole source of carbon for their growth.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.312-320
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• 2000

Abstract The full sequence of the plasmid pKJ36, which was derived from Bifidobacterium longum KJ, was determined and analyzed to construct shuttle vectors between E. coli and Bifidobacterium. The plasmid pKJ36 was composed of 3,625 base pairs with a 65.1% G+C content. The structural organization of pKJ36 was highly similar to that of pKJ50, and the three major ORFs on pKJ36 showed high amino acid sequence homologies with those of pKJ50. The putative proteins coded by these three ORFs were designated as RepB (32.0 kDa, pI=9.25), MembB (29.0 kDa, pI=12.25), and MobB (39.0 kDa, pI=IO.66), respectively. The amino acid sequence of RepB showed a 57% identity and 70% similarity with that of the RepA protein of pKJ50. Upstream of the repB gene, the so-called iteron sequence was directly repeated four-and-ahalf times and a conserved dnaA box was identified. An amino acid sequence comparison between the MobB and MobA of pKJ50 revealed a 48% identity and 61 % similarity. A conserved oriT sequence with an inverted repeat identical to that of pKJ50 was also found upstream of the mobB gene. A hydropathy analysis of MembB revealed four possible transmembrane regions. The expressions of the repB and membB genes were confirmed by RT-PCR. The in vitro translation reaction of pKJ36 showed protein bands with anticipated sizes with respect to each putative gene product. S 1 endonuclease treatment and Southern hybridization suggested that pKJ36 replicates by a rolling circle mechanism via a single-stranded DNA (ssDNA) intermediate. A shuttle vector between E. coli and Bifidobacterium sp. was constructed using the pKJ36, pBR322, and staphylococcal chloramphenicol acetyl transferase (CAT) gene. The successful transformation of the Bifidobacterium strains was shown by Southern hybridization and PCR. The transformation efficiency differed from strain to strain and, depending on the electroporation conditions, with a range between $1.2{\times}10^1-2.6{\times}10^2{\;}cfu/\mu\textrm{g}$ DNA.X> DNA.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.186-191
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• 1994

The origin of the leading strand replication (ori) and of lagging strand replication (M-O) of R-plasmid pSBK203 was identified and its base sequence was determined. About 50 bp of ori sequence residues overlapped with the structural gene of rep. Sequence comparison reveals that pSBK-ori shares obvious identities with those of pT181 family and consists of two regions, one is conserved and the other is variable region. Of two palindrome sequence located one after another in upstream region of rep gene, palA' instead of palA which shares sequence homology with diverse family of plasmids such as pOX6, pC194, and pE194 seems to act as a signal for conversion of primarily replicated ssDNA to dsDNA (minus origin (M-O)).

• KSBB Journal
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• v.8 no.2
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• pp.133-142
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• 1993

The effects of genetic and environmental factors on productivity of a cloned protein were studied in recombinant Saccharomyces cerevisiae. Plasmid stability and copy level were very high for a $REP^+$ system(at ca. 10 generations, stability: 65-90%, plasmid copy number per cell: 40-200), whereas these were very low for a yep- system(at ca. 10 generations, stability: 30%, plasmid copy number per cell 20). In plasmids containing the $2{\mu}m$ circle genome, a $[cir^o]$ strain was a preferred host cell since the plasmid stability and the copy number in a $[cir^o]$ strain were higher than in a $[cir^+]$strain. Cloned gene expression was dependent on plasmid copy number and stability. The inducer (galactose) level played a very important role in cloned lacZ gene expression, showing that a galactose concentration of 0.8% was sufficient for induction of gene expression. Induction rate was very fast in the case of plasmids exhibiting high stability and copy number by a factor of 4 to 25. The time to reach the peak value of gene expression was longer when galactose was added at the start of fermentation (ca. 26 hours) than at the mid-exponential phase (ca. 6 hours). Glucose repression was reduced by a factor of 2 to 5 as the relative inducer level increased.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.482-488
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• 2019

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. Replicase (Rep) proteins are considered essential for viral replication. Capsid (Cap) protein is the primary immunogenic protein that induces protective immunity. Little is known about comparison on the immunogenicity of PCV2 Rep and Cap fusion protein and Cap protein. In the present study, recombinant baculoviruses expressing the Rep-Cap fusion protein (Bac-Rep-Cap) and the Cap protein (Bac-Cap) of PCV2 were constructed and confirmed with western blot and indirect fluorescence assay. Immunogenicities of the two recombinant proteins were tested in mice. The titers of antibodies were determined with a PCV2-specific enzyme-linked immunosorbent assay (ELISA) and a serum neutralization assay. The $IFN-{\gamma}$ response of immunized mice was measured by ELISA. The mice immunized with the Bac-Rep-Cap and Bac-Cap successfully produced Cap-specific immunoreaction. The mice immunized with the Bac-Cap developed higher PCV2-specific neutralizing antibody titers than mice injected with the Bac-Rep-Cap. $IFN-{\gamma}$ in the Bac-Rep-Cap group was increased compared to those in the Bac-Cap group. Vaccination of mice with the Bac-Rep-Cap showed significantly decreased protective efficacy compared to the Bac-Cap. Our findings will indubitably not only lead to a better understanding of the immunogenicity of PCV2, but also improved vaccines.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.91-97
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• 1999

In this work, a 1.9-kb region of enterococcal plasmid p703/5 was isolated and the nucleotide sequence analysis of the region was performed. One major open reading frame (ORF) was identified encoding a polypeptide of 28 kDa. Database comparisons suggested that the protein showed some homology with other bacterial RepA proteins. Upstream of the ORF, a potential dnaA box, AT-rich region and 22-bp tandemly repeated sequences (DNA iterons), a feature typical for many replication ori sites, were recognized. Deletion analysis using Exonuclease III and several restriction enzymes indicated that the three elements and the gene product from the ORF were essential for replication and that the minimum unit of DNA required for replication resided on the 1.2-kb AvaII subfragment. Thus, this gene product was referred to as RepA.