• The Journal of the Korean Society for Microbiology
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• v.21 no.4
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• pp.461-471
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• 1986

Shigella strains isloated in the Teagu area during the period from 1973 to 1985 were studied for species distribution, drug resistance, and R plasmids. Approximately 1,200 strains were isolated during this period, and most of them were classified into Shigella flexneri, S. sonnei occupied less than 20%, and S. dysenteriae and S. boydii were very rarely isolated. More than 95% of them were resistant to one or more of these drugs; chloramphenicol (Cm), tetracycline (Tc), streptomycin (Sm), sulfisomidine (Su), ampicillin (Ap), and trimethoprim (Tp). Strains resistant to kanamycin, nalidixic acid (Na), and rifampin (Rf) were rare, and no strain was resistant to cephaloridine, gentamicin, and amikacin. Approximately half of the isolates were resistant to drugs in 1973, but the rate of resistant strains increased to more than 95% from 1977. Strains resistant to the four drugs (Cm, Tc, Sm, and Su) occupied the majority of resistant strains until 1977, but the most prevalent multiplicity of drug resistance increased to six drugs (Cm, Tc, Sm, Su, Ap, and Tp) from 1978 with the marked increase of Ap- and Tp-resistant strains. Approximately 75% of them transferred resistance to Escherichia coli by conjugation, and the resistance was considered to be mediated by R plasmids. Almost all of them transferred the complete patterns of resistance to drugs except Na and Rf. However, among some strains of recent isolates, small numbers of segregants of transferred resistance were observed. The R plasmids in Shigella were mostly classified into Inc FII, and only small numbers into Inc B. Segregants were in most cases unclassified.

• Journal of fish pathology
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• v.9 no.2
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• pp.195-201
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• 1996

Ninety-six isolates of Edwardsiella tarda recovered from outbreaks of Edwardsiellosis in cultured eels(Anguilla japonica) in Kunsan, were examined for drug susceptibility, distribution and transferabilities of R plasmid. All of the E. tarda isolates examined were sensitive to gentamicin(GM), streptomycin(SM), norfloxacin(NF), and amikacin(AK). But most isolates were resistant to sulfadimethoxine(SD, 86 strains), ampicillin(AM, 84 strains), penicillin G(PM, 80 strains), nalidixic acid (NA, 67 strains), oxytetracycline(OT, 44 strains), and oxolinic acid(OA, 37 strains). Twenty different combinations of drug resistance patterns were observed : the frequently encountered pattern was SD-AM-PM-NA-OA(16 strains), SD-AM-PM-NA(14 strains), SD-AM-PM-NA-OT-OA(12 strains), SD-AM-PM-OT(10 strains), and SD-AM-PM-NA-OT(8 strains). Transferable R plasmids were found out to be carried in 78 out of 94 resistant strains, indicating that these isolates carry conjugally transferable R plasmids associated with single or multiple drugs. The frequently observed transferarble R plasmids were AM(8 strains), AM-PM-NA(8 strains), Am-SD(6 strains), PM(6 strains), and SD(6 strains) These results suggest that high dose of various antibacterials might have already been introduced to eel culture system leading to the acquirement of multi-drug resistance to wide range of antibacterials.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.77-83
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• 2006

A gene encoding a $\gamma-butyrolactone$ autoregulator receptor was cloned from Saccharopolyspora erythraea, and the biochemical characteristics, including the autoregulator specificity, were determined with the purified recombinant protein. Using primers designed for the conserved amino acid sequence of Streptomyces $\gamma-butyrolactone$ autoregulator receptors, a 120 bp S. erythraea DNA fragment was obtained by PCR. Southern and colony hybridization with the 120 bp fragment as a probe allowed to select a genomic clone of S. erythraea, pESG, harboring a 3.2 kb SacI fragment. Nucleotide sequencing analysis revealed a 615 bp open reading frame (ORF), showing moderate homology (identity, $31-34\%$; similarity, $45-47\%$) with the $\gamma-butyrolactone$ autoregulator receptors from Streptomyces sp., and this ORF was named seaR (Saccharopolyspora erythraea autoregulator receptor). The seaR/pET-3d plasmid was constructed to overexpress the recombinant SeaR protein (rSeaR) in Escherichia coli, and the rSeaR protein was purified to homogeneity by DEAE-Sephacel column chromatography, followed by DEAE-ion-exchange HPLC. The molecular mass of the purified rSeaR protein was 52 kDa by HPLC gel-filtration chromatography and 27 kDa by SDS-polyacrylamide gel electrophoresis, indicating that the rSeaR protein is present as a dimer. A binding assay with tritium-labeled autoregulators revealed that rSeaR has clear binding activity with a VB-C-type autoregulator as the most effective ligand, demonstrating for the first time that the erythromycin producer S. erythraea possesses a gene for the $\gamma-butyrolactone$autoregulator receptor.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.221-226
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• 2000

Cephalosporin-C deacetylase (CAH) catalyzes the deacetylation of cephalosporin derivatives. A novel gene encoding the CAH from Bacillus sp. KCCM10143 was cloned and sepuenced. The uncleotide sequence contained an open reading frame encoding a polypeptide consisting of 217 amino acids and a molecular weight of 24 kDa which was in good agreement with the value obtained by sodium dodecylsulfate-polyacrylamide gel electrophoresis. An expression plasmid was constructed by inserting the CAH gene into the region of the pTrc99A expression vector. An active from of the CAH protein was expressed in the soluble fraction obtained after cell disruption. in fermentation using a 5-1 jar fementer, the transformant E. coli JM109 (pDST654) produced 4.12 U of CAH per ml of culture during 16 h of incubation.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.69-77
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• 1986

The purpose of this study was the examination for presence of K99 antigen (K99), enterotoxigenicity, 0-groups, colicin and antibiotic susceptibility among E. coil isolated from calves and cows. A total of 49(18.7%) among 262 strains, isolated from 30(26.5%) out of 113 calves and cows, possesed K99, and thirty three of 49 $K99^+$ strains produced ST. Of the strains of diarrheal calf origin which less than 15 days old, a high correlation was observed between enterotoxigenic ability and K99: 92.3% of the $K99^+$ strains produced heat stable enterotoxin(ST). In O group typing of 33 $ST^+$ strains, they belonged to O20(48.4%), O8(9.1%), O9(6.1%), O139(6.1%), O149(6.1%), O101(3.0%), O115(3.0%), except six which were untypable or autoagglutinable. Of 262 E. coil isolates, 30 strains(13.3%) produced colicin and K99 were detected in 6 strains. One hundred eighty eight strains(71.8%) of 262 E. coil isolates were resistance to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, alone or in combination thereof. One hundred and fourteen(60.6%) out of 188 drug resistance strains carried R factor($R^+$) which were transferable to the recipients by conjugation. Sixty five $R^+$ strains(57.0%) carried thermo-sensitive R plasmid.

• Journal of fish pathology
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• v.8 no.1
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• pp.31-36
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• 1995

Hc nuclear polyhedrosis virus DNA genome was digested with EcoRI endonuclease, these partial fragments were recombined into the pUC8 plasmid vector and transformed in E. coli JM 83 cell. The genome DNA has 24 EcoRI fragments and 12 fragments of them were subcloned. The four recombinants were named as eNP-O, eNP-Q, eNP-R and eNP-S. The expression of foregin gene of the recombinants was investigated by analysing protein patterns on the SDS-PAGE. The eNP-O, eNP-Q and eNP-R were expressed a different weight of protein as comparision with potypeptide bands of E. coli JM 83 host cell.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.222-227
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• 1991

Rhizobium fredii USDA193 is one of the causal organism for root nodule formation in soybean (peking). Previously we cloned the pectate lyase gene (SY1) of R. fredii USDA193. The $pel^-$ mutants (SY1$\Omega$ and SY1$\Omega$1) of SY1 were obtained using the in vitro insertional omega mutagenesis of RpelB (of Rhizobium pel) and fill-in reaction of RpelE (of Rhizobium pel) gene respectively, and we constructed two mutants (R, fredii USDA193$\Omega$ and R. fredii USDA193$\Omega$1) in pectate lyase function by marker-exchange with pe1B::$\Omega$ and R. fredii USDA193 strain (rif). The pectate lyase activity of two pel- mutant of R. fredii USDA193 was determined by spectrophotometric method. However, all pectate lyase activity of these mutants was not lost upon the mutagenesis by marker-exchange. This suggests that other pectate lyase genes may be present on the plasmid or the chromosome of R. fredii. As yet we do not have evidence linking RpelB and RpelE genes of R. fredii directly to the early nodulation process.

• Journal of Life Science
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• v.14 no.2
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• pp.368-373
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• 2004

We have obtained fertile transgenic rice plants resistant to the broad spectrum herbicide Bast $a^{(R)}$ (active ingredient phosphinothricin, PPT) by PEG-mediated transformation procedure. The plasmid pCaMV35S::Bar was used to deliver the bar gene into embryogenic suspension culture-derived protoplasts of rice (Oryza sativa L.). Transformed plants were regenerated and selected on medium containing 15 mg/l of phosphinothricin. Stable integration and expression of the bar gene in transgenic rice plants was confirmed by Southern and Northern blot analysis. Transgenic $R_1$ plants were also confirmed by assays for phosphinothricin acetyltransferase (PAT) activity. The bar gene was expressed in the primary transgenic rice plants and in the next generation progeny, in which it showed a 3 : 1 Mendelian inheritance pattern. Transgenic $R_1$ and $R_2$ plants were resistant to the herbicide Bast $a^{(R)}$ when sprayed at rates used in field practice.ice.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.828-836
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• 2008

The biocontrol rhizobacterium Pseudomonas sp. M18 can produce two kinds of antibiotics, namely pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA), and is antagonistic against a number of soilborne phytopathogens. In this study, a luxR-type quorum-sensing regulatory gene, vqsR, was identified and characterized immediately downstream of the Plt gene cluster in strain MI8. A vqsR-inactivated mutant led to a significant decrease in the production of Plt and its biosynthetic gene expression. However, this was restored when introducing the vqsR gene by cloning into the plasmid pME6032 in trans. The vqsR mutation did not exert any obvious influence on the production of PCA and its biosynthetic gene expression and the production of N-acylhomoserine lactones (C4 and C8-HSLs) and their biosynthetic gene rhlI expression. Accordingly, these results introduce VqsR as a regulator of Plt production in Pseudomonas spp., and suggest that the regulatory mechanism of vqsR in strain M18 is distinct from that in P. aeruginosa. In addition, it was demonstrated that vqsR mutation did not have any obvious impact on the expression of Plt-specific ABC transporters and other secondary metabolic global regulators, including GacA, RpoS, and RsmA.

• Journal of Ginseng Research
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• v.45 no.6
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• pp.754-762
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• 2021

Background: Ginsenoside Rh2, a major saponin derivative in ginseng extract, is recognized for its anti-cancer activities. Compared to coding genes, studies on long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) that are regulated by Rh2 in cancer cells, especially on competitive endogenous RNA (ceRNA) are sparse. Methods: LncRNAs whose promoter DNA methylation level was significantly altered by Rh2 were screened from methylation array data. The effect of STXBP5-AS1, miR-4425, and RNF217 on the proliferation and apoptosis of MCF-7 breast cancer cells was monitored in the presence of Rh2 after deregulating the corresponding gene. The ceRNA relationship between STXBP5-AS1 and miR-4425 was examined by measuring the luciferase activity of a recombinant luciferase/STXBP5-AS1 plasmid construct in the presence of mimic miR-4425. Results: Inhibition of STXBP5-AS1 decreased apoptosis but stimulated growth of the MCF-7 cells, suggesting tumor-suppressive activity of the lncRNA. MiR-4425 was identified to have a binding site on STXBP5-AS1 and proven to be downregulated by STXBP5-AS1 as well as by Rh2. In contrast to STXBP5-AS1, miR-4425 showed pro-proliferation activity by inducing a decrease in apoptosis but increased growth of the MCF-7 cells. MiR-4425 decreased luciferase activity from the luciferase/STXBP5-AS1 construct by 26%. Screening the target genes of miR-4425 and Rh2 revealed that Rh2, STXBP5-AS1, and miR-4425 consistently regulated tumor suppressor RNF217 at both the RNA and protein level. Conclusion: LncRNA STXBP5-AS1 is upregulated by Rh2 via promoter hypomethylation and acts as a ceRNA, sponging the oncogenic miR-4425. Therefore, Rh2 controls the STXBP5-AS1/miR-4425/RNF217 axis to suppress breast cancer cell growth.