• 대한임상검사과학회지
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• 제43권2호
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• pp.68-74
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• 2011

Pseudomonas aeruginosa is an aerobic, Gram-negative, glucose-nonfermenting bacterium, which has emerged as a serious opportunistic pathogen. Recently, outbreaks of carbapenem resistant P. aeruginosa give rise to significant therapeutic challenges for treating nosocomial infections. The genes of metallo-${\beta}$-lactamase (MBL), a powerful carbapenemase, are carried as a part of the mobile gene cassettes inserted into integrons playing an important role in rapid dissemination of antibiotic resistance genes among bacterial isolates. In this study, we investigated the prevalence of integron in imipenem resistant P. aeruginosa isolates. A total of 61 consecutive, non-duplicate, and imipenem resistant P. aeruginosa strains were isolated from a university hospital in the Chungcheong province of Korea. We employed repetitive extragenic palindromic sequence-based PCR (rep-PCR) method for the selection of clonally different P. aerusinosa strains. PCR and DNA sequencing were conducted for the detection of integrons. Twenty-one clonally different P. aeruginosa strains were isolated. Only one (P28) of the strains harbored $bla_{VIM-2}$ that was found as gene cassettes in class 1 integrons. Four of 21 carbapenem resistant P. aeruginosa strains harbored class 1 integron containing aminoglycoside resistance determinant. All of the integrons detected in the study contained more than one resistance gene cassette, which can mediate resistance to multiple antibiotics. To prevent further spreading of the multi-drug resistant P. aeruginosa, conseguent monitoring and clinical polices are required.

• Journal of Microbiology
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• 제34권1호
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• pp.30-36
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• 1996

We have exmained the re-establishment of HIMRE mediated silencing function on the transcriptional activity of yeast heast shock gene HSP82. To test whether the onset of SIR repression can occur in growing cells in the rpesence of a potent inhibitor of DNA replication, HMRa/HSP82 strains with SIR4- and SIR4S$^{+}$ genetic backgrounds were arrested in S phase by incubation of a culture in 200 mM hydroxyurea for 120 min. It was clear that following a 20 minute heat shock, silencing of the HMRa/HSP82 allele in cells pretreated with hydroxyurea does occur in a SIR4-dependen fashion, even though the kinetics of repression appears to be substantially delayed. We also have tested whether re- establishement of silencing at the HMR/hsp82 locus can occur in G1-arrested cells. Cell cycle arrest at G1 phase was achieved by treatment of early log a cell cultures with .alpha.-factor mating pheromone, which induces G1 arrest. The result suggests that passage through S phase (and therefore DNA replication) is nor required for re-establishing silencer-mediated repression at the HMNRa/HSP82 locus. Finally, to test whether de nono protein synthesis is required for re-establishment of silencer-mediated repression, cells were pretreated with cycloheximide (500 /.mu.g/ml) 120 min. It was apparent that inhibiting protein synthesis delays, but does not prevent, re-establishment of silencer-mediated repression. Altogether, these results indicate that re-establishment of silencer-mediated repression is not dependent on the DNA replication and has no requirement for protein synthesis.s.

• 전력전자학회논문지
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• 제24권1호
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• pp.40-48
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• 2019

Hybrid electric propulsion systems (H-EPSs) are an intermediate step for integrated full electric propulsion warships. H-EPSs are a dynamic combination of mechanical and electrical propulsion systems to achieve the required mission performances. The system modes could adapt to meet the requirement of the various operation conditions of a warship. This paper presents a configuration and operating modes of H-EPSs considering the operation conditions of a destroyer class warship. The system has three propulsion modes, namely, motoring mode, generating mode [power take off (PTO) mode], and mechanical mode. The PTO mode requires a careful fuel efficiency analysis because the fuel consumption rate of propulsion engines may be low compared with the generator's engines depending on the loading power. Therefore, the calculation of fuel consumption according to the operating modes is performed in this study. Although the economics of the PTO mode depends on system cases, it has an advantage in that it ensures the reliability of electric power in case of blackout or minimum generator operation.

• Journal of Animal Science and Technology
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• 제66권1호
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• pp.232-236
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• 2024

Ligilactobacillus is a genus of Gram-positive lactobacilli commonly found in the intestinal tracts of vertebrates. It has been granted a Qualified Presumption of Safety (QPS) status from the European Food Safety Authority (EFSA). One specific strain, Ligilactobacillus salivarius B4311, was isolated from fecal samples of broiler chickens from a farm associated with Chung-Ang University (Anseong, Korea). This strain was observed to have inhibitory effects against Listeria monocytogenes. In this paper, we present the complete genome sequence of Lig. salivarius B4311. The whole genome of strain B4311 comprises 2,071,255 bp assembled into 3 contigs representing a chromosome, repA-type megaplasmid, and small plasmid. The genome contains 1,963 protein-coding sequences, 22 rRNA genes, and 78 tRNA genes, with a guanine + cytosine (GC) content of 33.1%. The megaplasmid of strain B4311 was found to contain the bacteriocin gene cluster for salivaricin P, a two-peptide bacteriocin belonging to class IIb.

• Journal of Microbiology
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• 제42권2호
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• pp.87-93
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• 2004

Twelve mecoprop-degrading bacteria were isolated from soil samples, and their genetic and phenotypic characteristics were investigated. Analysis of 16S rDNA sequences indicated that the isolates were related to members of the genus Sphingomonas. Ten different chromosomal DNA patterns were obtained by polymerase-chain-reaction (PCR) amplification of repetitive extragenic palindromic (REP) sequences from the 12 isolates. The isolates were found to be able to utilize the chiral herbicide meco-prop as a sole source of carbon and energy. While seven of the isolates were able to degrade both (R)-and (S)-mecoprop, four isolates exhibited enantioselective degradation of the (S)-type and one isolate could degrade only the (R)-enantiomer. All of the isolates were observed to possess plasmid DNAs. When certain plasmids were removed from isolates MPll, MP15, and MP23, those strains could no longer degrade mecoprop. This compelling result suggests that plasmid DNAs, in this case, conferred the ability to degrade the herbicide. The isolates MP13, MP15, and MP24 were identified as the same strain; however, they exhibited different plasmid profiles. This indicates that these isolates acquired dif-ferent mecoprop-degradative plasmids in different soils through natural gene transfer.

• Journal of Microbiology
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• 제45권4호
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• pp.344-349
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• 2007

We have isolated previously three synthetic lethal mutants in Schizosaccharomyces pombe, which genetically interact with mex67, in order to identify the genes involved in mRNA export. A novel nup97 gene was isolated by complementation of the growth defect in one of the synthetic lethal mutants, SLMex3. The nup97 gene contains one intron and encodes an 851 amino-acid protein that is similar to nucleoporins, Nppl06p in S. pombe and Nic96p in Saccharomyces cerevisiae. The nup97 gene is essential for vegetative growth, and nup97 null mutant harboring pREP41X-Nup97 showed $poly(A)^+$ RNA export defect when expression of nup97 is repressed in the presence of thiamine. These results suggest that nup97 is involved in mRNA export from the nucleus to cytoplasm.

• ETRI Journal
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• 제38권3호
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• pp.479-486
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• 2016

System-on-chip (SoC) designs have a number of flip-flops; the more flip-flops an SoC has, the longer the associated scan test application time will be. A scan shift operation accounts for a significant portion of a scan test application time. This paper presents physical-aware approaches for speeding up scan shift operations in SoCs. To improve the speed of a scan shift operation, we propose a layout-aware flip-flop insertion and scan shift operation-aware physical implementation procedure. The proposed combined method of insertion and procedure effectively improves the speed of a scan shift operation. Static timing analyses of state-of-the-art SoC designs show that the proposed approaches help increase the speeds of scan shift operations by up to 4.1 times that reached under a conventional method. The faster scan shift operation speeds help to shorten scan test application times, thus reducing test costs.

• 미생물학회지
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• 제32권2호
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• pp.115-119
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• 1994

Staphylococcus aureus DH1에서 분리된 R-plasmid pSBK203상의 복제개시 인자인 rep 유전자산물의 발현이 어떻게 조절되는가를 밝히기 위해 관련 부위를 확인하고 cloning한 후 그 염기서열을 결정하였으며 이를 같은 계열에 속하는 pT181족 plasmid들의 서열과 그 상동성을 비교 분석하였다. 복제 조절 관련 부위에 염기 삽입 및 염기 결손을 유도함으로써 얻어진 변이체들의 copy수를 측정하여 그 복제 조절 기능에 초래된 변화를 확인하였다.

• 미생물학회지
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• 제42권2호
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• pp.153-155
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• 2006

mRNA의 핵에서 세포질로의 이동에 관여하는 발아효모 Saccharomyces cerevisiae의 SAC3유전자와 유사한 분열효모 Schizosaccharomyces pombe의 유전자 (spSac3로 명명)의 결실돌연변이주 (knockout mutant)를 제조하여 그 특성을 조사하였다. S. pombe의 이배체 (diploid) 균주에서 한 spSac3 유전자만을 결실시킨 후 4분체분석 (tetrad analysis)을 수행한 결과, 이 유전자는 성장에 필수적이었다. 또한 in situ hybridization을 통해 세포 내의 poly(A)+ RNA분포를 살펴본 결과, spSac3 유전자의 결실돌연변이주는 mRNA의 핵에서 세포질로의 이동에 이상이 있었다. 이와 같은 결과들은 spSac3 유전자 역시 mRNA의 핵에서 세포질로의 이동에 매우 중요한 역할을 담당하고 있음을 시사한다.

• 한국축산식품학회지
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• 제38권4호
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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.