• 한국어병학회지
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• 제36권2호
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• pp.287-292
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• 2023

This study investigated the genetic determinants of plasmid-mediated antibiotic resistance (PMAR) to quinolones and tetracycline in 106 Aeromonas strains isolated from eel (Anguilla japonica, 70 strains) and ornamental fish (36 strains) in Korea. Quinolones and tetracycline resistance phenotypes were found to be widely distributed throughout the both fish groups. However, the prevalence of qnr and tet genes was higher in ornamental fish strains than in eel strains (42.9% vs. 86.1% for qnr and 51.4% vs. 69.4% for tet). In addition, the profiling of the present genetic determinants revealed the dominance of qnrS, tetA, tetE and tetE+qnrS genes for eel strains but of tetA+qnrS qnrS and tetE+qnrS genes for ornamental fish strains. These results indicate that aquaculture and related industries could be a major threat to public health due to the possible spread of PMAR.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.7-12
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• 2001

Three Pseudomonas strains (Bk8, Bk9, Bk10) selected from soil for their ability to degrade herbicide diuron were tested for their heavy metal resistance. The growth of these catabolic strains on a minimal medium with various concentrations of $Cd^{2+},\;Zn^{2+},\;Ni^{2+}$, and $Hg^{2+}$ revealed a minimal effect on the carbon source for the inhibitory effect of the metals. One of these strains, namely, Bk8, exhibited a high resistance to the heavy metals as compared to the two other strains. This strain harbors plasmid pBk8 (110 kb) and contains at least fur determinants encoding heavy metal resistance. Nickel and zinc resistance are encoded by genes located on the chromosome, while cadmium and mercury resistance are on plasmid pBk8. Accordingly, the characteristics of strain Bk8 suggest that it would be useful in the bioremediation of aromatic compounds in the presence of toxic heavy metals as co-contaminants.

• 대한임상검사과학회지
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• 제52권2호
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• pp.136-142
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• 2020

세균의 항균제 내성율은 지난 몇십년 동안 지속적으로 상승하였으며 mobile genetic elements를 통한 항균제내성인자들의 전파는 다제내성세균의 출현 및 확산을 가중시켰다. 본연구에서는 임상검체에서 분리된 aminoglycoside에 비감수성 대장균 33주를 대상으로 mobile genetic elements를 통해 전파될 수 있는 aminoglycoside 내성인자를 조사하였다. 16S ribosomal RNA methyltransferases (RMTases)와 aminoglycoside-modifying enzyme (AME)유전자가 PCR과 DNA 염기서열분석을 통해 검출되었다. 그 결과 aac(3')-II 유전자(54.5%)를 포함하고 있는 균주가 제일 많았으며 그 다음으로 aph(3')-Ia 유전자(18.2%)가 많았고 aac(6')-Ib 유전자(15.2%)를 포함하는 균주도 있었다. RMTase 유전자는 본 연구에서는 검출되지 않았다. aac(3')-II 유전자를 포함하고 있는 18균주 중 17균주가 gentamicin에 내성을 보였으며 이중 16균주는 tobramycin에도 내성을 보였다. aac(6')-Ib 유전자를 포함하고 있는 5균주는 모두 tobramycin에 내성을 보였다. 본 연구에서 AME 유전자를 획득하는 것은 사람에서 분리된 대장균이 aminoglycoside에 내성을 나타내는 중요한 기전 중 하나임이 확인되었다. 사람으로부터 분리된 세균을 대상으로 지속적으로 항균제 내성인자를 조사하는 것은 내성세균의 확산을 막는데 필요할 것으로 사료된다.

• 대한임상검사과학회지
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• 제50권2호
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• pp.100-109
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• 2018

다제내성(multidrug-resistant, MDR) Acinetobacter baumannii 균주의 출현 및 확산이 전 세계적으로 보고되어 왔는데, 이들 대부분은 생물막 형성능력을 가지고 있다. 생물막 형성은 소독 및 건조에 대해 세균이 저항할 수 있도록 해주는 중요한 병독성 인자이다. 본 연구에서는 생물막을 형성하는 A. baumannii 임상 분리주를 대상으로 항균제 내성 기전에 대한 유전적 기초를 조사하였다. 크리스탈 바이올렛 분석법을 통해 생물막 형성능력을 확인한 결과 46균주가 생물막을 형성하는 것으로 나타났다. 이어서 REP-PCR을 수행하여 서로 다른 클론에 속하는 16 균주를 선택한 후 이 균주들을 대상으로 항균제 내성 인자를 검출하였다. 본 연구에서 분리된 9개 non-MDR (0.96) 균주와 7개의 MDR (1.05) 균주의 평균 생물량은 서로 달랐지만, 이 차이는 유의하지 않았다. 대부분의 생물막 형성 MDR 균주는 다양한 항균제 내성인자 ($bla_{OXA-23}$, armA 및 gyrA 및 parC의 돌연변이)를 가지고 있는 것으로 나타났다. 그러나 대부분의 non-MDR 균주는 항균제 내성인자를 포함하지 않는 것으로 나타났다. 우리의 결과는 A. baumannii 균주의 생물막 형성능력이 항균제 감수성과 상관관계가 적음을 시사한다. 또한 MDR A. baumannii 임상 분리주의 출현은 대개 항균제 내성과 관련된 유전자의 돌연변이나 또는 다양한 항균제 내성인자의 획득에 의한 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.199-206
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• 2008

Four hundred and thirteen oxytetracycline-resistant bacteria were recovered from six freshwater giant prawn farms with a history of oxytetracycline use. Most oxytetracycline-resistant isolates were Gram-negative bacteria. Six groups of oxytetracycline-resistant bacteria were classified using cluster analysis based on a comparison of levels of oxytetracycline resistance. Complex fingerprint patterns were obtained for 71 isolates studied. In general, the band patterns of isolates from different ponds were very similar, and the data indicated that the isolates were closely related. The exploration for cross-resistance found that most of the 71 oxytetracycline-resistant isolates were also resistant to tetracycline and chlortetracycline, but had a relatively low resistance to doxycycline. Many isolates showed higher chlortetracycline resistance than oxytetracycline resistance. Additionally, the oxytetracycline-resistant isolates were examined for the presence of tetracycline resistance (tet) genes. Fifty percent of the isolates carried one of the 14 known tet genes examined. The most common determinants were TetA and TetD. However, TetB, TetC, TetE, TetK, TetL, and TetM were also found with various frequencies.

• 대한의생명과학회지
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• 제27권4호
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• pp.195-207
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• 2021

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen capable of causing human diseases, such as soft tissue infection, bacteremia, endocarditis, toxic shock syndrome, pneumonia, and sepsis. Although the incidence rate of diseases caused by MRSA has declined in recent years, these diseases still pose a clinical threat due to their consistently high morbidity and mortality rates. However, the role of virulence factors in staphylococcal infections remains incompletely understood. Methicillin resistance, which confers resistance to all β-lactam antibiotics in cellular islets, is mediated by the mecA gene in the staphylococcal cassette chromosome mec (SCCmec). Differences in SCCmec types and differences in their sizes and structures serve epidemiological purposes and are used to differentiate between hospital-associated (HA)-MRSA and community-associated (CA)-MRSA. Some virulence factors of S. aureus are also providing a distinction between HA-MRSA and CA-MRSA. These factors vary depending on the presence of toxins, adhesion, immune evasion, and other virulence determinants. In this review, we summarized an overview of MRSA such as resistance mechanisms, SCCmec types, HA- and CA-MRSA, and virulence factors that enhance pathogenicity or MRSA epidemiology, transmission, and genetic diversity.

• Journal of Plant Biotechnology
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• 제38권1호
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• pp.94-104
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• 2011

Salt stress is a major environmental factor influencing plant growth and development. To identify salt tolerance determinants, we systematically screened salt sensitive rice mutants by use of the Activator/Dissociation (Ac/Ds) transposon tagging system. In this study, we focused on the salt sensitive mutant line, designated SSM-1. A gene encoding a NAC transcription factor homologue was disrupted by the insertion of a Ds transposon into SSM-1 line. The OsNAC075 gene (EU541472) has 7 exons and encodes a protein (486-aa) containing the NAC domain in its N-terminal region. Sequence comparison showed that the OsNAC075 protein had a strikingly conserved region at the N-terminus, which is considered as the characteristic of the NAC protein family. OsNAC075 protein was orthologous to Arabidopsis thaliana ANAC075. Phylogenetic analysis confirmed OsNAC075 belonged to the OsNAC3 subfamily, which plays an important role in response to stress stimuli. RT-PCR analysis showed that the expression of OsNAC075 gene was rapidly and strongly induced by stresses such as NaCl, ABA and low temperature ($4^{\circ}C$). Our data suggest that OsNAC075 holds promising utility in improving salt tolerance in rice.

• 대한수의학회지
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• 제59권4호
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• pp.207-211
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• 2019

Mass mortality in commercially cultured Amur catfish (Silurus asotus), showing symptoms of dermal ulcerations, occurred on a private farm in Mar 2019 in Korea. β-hemolytic bacteria were isolated from the ulcers and kidneys of the fish and identified as Aeromonas veronii. The isolate was resistant to tetracycline and possessed cytotoxic heat-labile enterotoxin (aerolysin/hemolysin). We investigated the genetic determinants associated with tetracycline resistance, and the isolate has been confirmed to simultaneously possess tetA and tetE genes. This is the first report on the occurrence of tetracycline-resistant A. veronii infection related to mass mortality in commercially cultured Amur catfish in Korea.

• 대한물리치료과학회지
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• 제8권1호
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• pp.745-758
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• 2001

The purpose of study to phenomenological examine and the mechanism regarding the gene(DNA, RNA, Protein) and sports to studied, analyzed. and evaluated. This review considers the evidence for genetic effects in several determinants of endurance performance and resistance performance, namely: body measurements and physique, body fat pulmonary functions, cardiac and circulatory functions, muscle characteristics. substrate utilization, maximal aerobic power and other. Moreover, the response to aerobic training of indicators aerobic work metabolism and endurance performance is reviewed, with emphasis on the specificity of the response and the individual differences observed in training ability. This study indicate that improvement of 'Enhancer Action' in RNA genes changed by exercise or sports. Moreover exercise was effect on Central Dogma with DNA makes RNA makes Protein. and think that occurred with exercise influence on skeletal muscle into cell have to Myosin Heavy Chain (MHC) changed was after exercise performance, which accompanied into skeletal muscle that were exercise-induces gene-modulation that is, take gene mutations. This study known that existed hormone(epinephrine)-immune system with interaction. Exercise were altered insulin binding and MAP Kinase signaling increased into immune cells. This review suggested that the high rate of glutamine utilization by cells of the immune system serves to maintain a high intra cellular concentration of the intermediates of biosynthetic pathways such that optimal rates of DNA, RNA and protein synthesis can be maintained. In the absence of glutamine, lymphocytes do not proliferate in vitro: proliferation increase greatly as the glutamine concentration increase. Glutamine is synthesized in skeletal muscle. Skeletal muscle and plasma glutamine levels are lowered by sepsis, injury, bums, surgery and endurance exercise and in the overtrained athlete. The study of result show that production of ET-1 is markedly increased tissue specifically in the heart by exercise without appreciable changes in endothelin-converting enzyme and endothelial receptor expressions, suggest that myocardial ET-1 may participate in modulation of cardiac function during exercise. Conclusionally, this study indicate that improvement of 'Enhancer Action' in RNA genes changed by exercise or sports. Moreover exercise was effect on Central Dogma with DNA makes RNA makes Protein. This study is expected to contribute the area of sports science, medicine, hereafter more effort is required to establish the relation between gene alters and exercise amount.