• 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.

• Microbiology and Biotechnology Letters
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• v.15 no.5
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• pp.319-327
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• 1987

In order to develop useful plasmid vectors for Zymomonas cells, attempts were made to isolate natural plasmids from Z. mobilis ATCC10988. Among a few plasmids isolated, a small plasmid of 3.9 Kb size was chosen and designated as pZM3. By introducing the replication origin of pZM3 into pBR325, a hybrid plasmid vector of 8.4 Kb size, pHZ22, was constructed. This vector contained chloramphenicol resistant gene as a selectable marker and proved to be conjugally transmissible and stably maintained in Z. mobilis. Tetracycline resistant gene was isolated from RP4 and introduced into pHZ22 to make a new vector called pHZT224 of 10.7 Kb size. Through n series of experiments, it was evident that these plasmid vectors containing selectable markers of chloramphenicol and tetracycline resistance were shuttle vectors functional in Z. mobilis as well as E. coli.

• Microbiology and Biotechnology Letters
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• v.16 no.4
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• pp.270-274
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• 1988

Samples used for the enrichment culture were collected from the sea water of suspected chronic petroleum contamination in the vicinity of Pusan, Chungmu and Ulsan ports, Korea. Alkaline Iysis and agarose gel electrophoresis techniques were employed to screen these isolates for the presence of plasmid DNA. There were n little differences in the percentage of isolates containing plasmids between sampling sites of unpolluted sen water (22％) and polluted son water (25％). Bacterial isolates taken from the Bunker-C oil enriched culture showed significantly more plasmid incidence (29％). About two thirds of strains grown on a variety of hydrocarbons were Gram negative strains of which 33％ contained one or more plasmids. Multiple plasmids were observed in 23％ of the plasmid-carrying strains. Forty one percent of the plasmids detected were estimated to have a mass of 20 kb or more.

• Food Science of Animal Resources
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• v.38 no.4
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• pp.816-822
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• 2018

Bifidobacterium is recognized as one of the most beneficial microorganisms in our gut. Many researches on bifidobacteria have been done to understand their roles in the gut. The objective of the present study was to develop a bioluminescent labelling plasmid vector for bifidobacteria to facilitate their visualization in vitro, in situ, and in vivo. A plasmid replicon (2.0 kb) of plasmid pFI2576 previously identified from B. longum FI10564 was amplified by PCR and cloned into pUC19 plasmid vector (2.68 kb). The cloned replicon was subcloned into pTG262 ($luc^+$) recombinant plasmid vector (7.4 kb) where a luciferase gene ($luc^+$) from pLuc2 (8.5 kb), an Escherichia coli and lactobacilli shuttle vector, was inserted into pTG262 plasmid vector. The final recombinant DNA, pTG262::pFI2576 rep ($luc^+$), was transferred into a B. catenulatum strain. This recombinant strain showed 3,024 relative luminescence units at $OD_{600}$ value of 0.352. Thus, this recombinant plasmid construct can be broadly used for labelling bifidobacteria.

• Journal of fish pathology
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• v.12 no.2
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• pp.115-121
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• 1999

MIC test of 16 chemotherapeutic agents was performed on 24 isolates of Edwardsiella tarda collected from flounders. They revealed resistance against combinations of ampicillin, amoxicillin, erythromycin, flumequine, doxycycline(DOXY), nalidixic acid, novobiocin, oxolinic acid, oxytetracycline(OTC), thiamphenicol(TP) and sulfonamide. Two strains carried transferable R plasmid encoding Otc Kanamycin Tp and Otc chloramphenicol Doxy Tetracycline Tp, respectively. The R plasmids were not similar each other on the basis of their digestion pattern of restriction endonuclease, suggesting distribution of different transferable R plasmid among E. tarda from flounders.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1614-1620
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• 2015

Plasmid-cured derivative strains of Bacillus anthracis are frequently used in laboratory studies. Plasmid incompatibility, which does not increase the risk of chromosomal mutation, is a useful method for plasmid curing. However, in bacteria containing multiple plasmids, it often requires the sequential introduction of multiple, specific incompatibility plasmids. This lengthy process renders the traditional plasmid incompatibility method inefficient and mutation-prone. In this study, we successfully cured plasmids pXO1 and pXO2 from B. anthracis A16 simultaneously using only one recombinant incompatible plasmid, pKORT, to obtain a plasmid-free strain, designated A16DD. This method may also be useful for the simultaneous, one-step curing of multiple plasmids from other bacteria, including Bacillus thuringiensis and Yersinia pestis.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.31-38
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• 2002

Bacteria have evolved various types of resistance mechanism to toxic heavy metals, such as arsenic and antimony. An arsenical and antimonial resistant bacterium was isolated from a shallow creek draining a coal-mining area near Taebaek City, in Kangwon-Do, Korea. The isolated bacterium was identified and named as Pseudomonas sp. KM20 after biochemical and physiological studies were conducted. A plasmid was identified and its function was studied. Original cells harboring the plasmid were able to grow in the presence of 15 mM sodium arsenite, while the plasmid-cured (plasmidless) strain was sensitive to as little as 0.5 mM sodium arsenate. These results indicated that the plasmid of Pseudomonas sp. KM20 does indeed encode the arsenic resistance determinant. In growth experiments, prior exposure to 0.1 mM arsenate allowed immediate growth when they were challenged with 5 mM arsenate, 5 mM arsenite, or 0.1 mM antimonite. These results suggested that the arsenate, arsenite, and antimonite resistance determinants of Pseudomonas sp. KM20 plasmid were indeed inducible. When induced, plasmid-bearing resistance cells showed a decreased accumulation $of\;73^As$ and showed an enhanced efflux $of\;^73As$. These results suggested that plasmid encoded a transport system that extruded the toxic metalloids, resulting in the lowering of the intracellular concentration of toxic oxyanion. In a Southern blot study, hybridization with an E. coli R773 arsA-specific probe strongly suggested the absence of an arsA cistron in the plasmid-associated arsenical and antimonial resistance determinant of Pseudomonas sp. KM20.

• Archives of Pharmacal Research
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• v.27 no.12
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• pp.1263-1269
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• 2004

The objective of this study was to characterize immunoliposomes carrying plasmid DNA with optimal encapsulation efficiency and antibody density. Plasmid DNA was encapsulated by the freezing/thawing method into liposomes composed of POPC (1-palmitoyl-2-oleoyl-sn-glycerol- 3-phosphocholine), DDAB (didodecyl dimethyl ammonium bromide), DSPE-PEG 2000 (distearoyl phosphatidyl ethanolamine polyethylene glycol 2000) and DSPE-PEG 2000-maleimide. The liposomes carrying plasmid DNA were extruded through two stacked polycarbonate filters, of different pore size, to control the liposome size. Then, rat IgG molecules were conjugated to the liposomes. The immunoliposomes containing plasmid DNA were separated from the free plasmid DNA and unconjugated IgG by Sepharose CL-4B column chromatography. The DNA amount encapsulated was affected by DDAB (cationic lipid) concentration, the initial amount of plasmid DNA between 10 ${\mu}g$ and 200 ${\mu}g$, the total lipid amount and plasmid DNA size, but not significantly by liposome size. By varying the ratio of DSPE-PEG 2000-maleimide to IgG, the number of IgG molecules per liposome was changed significantly.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.345-348
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• 1985

Recombinant chimeric plasmid constructed with Xba I digested pUBl10 and -pE194 was transformed by polyethylene glycol induced protoplast transformation system into Bacillus subtilis BR 151 on the mannitol regeneration media, and two genes of antibiotics resistance were expressed simultaneously in the transfromant. Transformation frequency of the recombinant plasmid was 6.5 $\times$ 10$^{-5}$ on the mannitol regeneration agar plate containing neomycin and erythromycin. The replication of recombinant plasmid in the recipient cells was confirmed by the alkaline extraction method and agarose gel electrophoresis.

• Korean Journal of Microbiology
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• v.31 no.4
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• pp.286-291
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• 1993

The $Km^{r}$ gene and plasmid of natural isolate and genetically modified microorganisms (GMM) rearranged by conjugation in water environments were comparatively analyzed by agarose gel electrophoresis and Southern analysis. The transfer rates of the $Km^{r}$ gene from GMM strains were generally 100 times higher than thosc of natural iso]ate(DKI) under laboratory cnvironments, but their transfer rate was not much different in Moosimcheon River water. The conjugants obtained in LB(Luria-Bertani broth) and FW(filtered river water) water under laboratory conditions showed same number of the plasmids. but the sizes of the plasmids were changed. The $Km^{r}$ gene in the conjugants was found in the same position as the pDKJO] $Km^{r}$ plasmid. In case of the GMM strains as donor. the large plasmids of 180 kb appeared in conjugants obtained in LB and FW water. Especially, the $Km^{r}$ gene in the donor of DKC600 was found to be inserted into chromosome of the conjugant obtained in FW water. However. in the conjugants obtained from DKl and DKB 701 in Moosimcheon River water, the plasmids were rearranged by 4 and 8. respectively, and all of them showed hybridization by the $Km^{r}$ probe. But the small plasmids of the recipient disappeared in the conjugant from DKC600 as donor, and the rearranged plasm ids and chromosome in the conjugants were observed to be hybridized with the $Km^{r}$ probe. Therefore, rearrangement of $Km^{r}$ gene and plasmids by conjugation was found to be afTected diversely by cellular characteristics as well as by environmental factors.