• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.856-867
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• 2020

Vibrio parahaemolyticus is a major gastroenteritis-causing pathogen in many Asian countries. Antimicrobial resistance in V. parahaemolyticus has been recognized as a critical threat to food safety. In this study, we determined the prevalence and incidence of antimicrobial resistance in V. parahaemolyticus in the southern Fujian coast, China. A total of 62 isolates were confirmed in retail aquatic products from June to October of 2018. The serotype O3:K6 strains, the virulence genes tdh and trh, antibiotic susceptibility and molecular typing were investigated. Then plasmid profiling analysis and curing experiment were performed for multidrug-resistant strains. The results showed that the total occurrence of V. parahaemolyticus was 31% out of 200 samples. Five strains (8.1%) out of 62 isolates were identified as the V. parahaemolyticus O3:K6 pandemic clone. A large majority of isolates exhibited higher resistance to penicillin (77.4%), oxacillin (71%), ampicillin (66.1%) and vancomycin (59.7%). Seventy-one percent (44/62) of the isolates exhibited multiple antimicrobial resistance. All 62 isolates were grouped into 7 clusters by randomly amplified polymorphic DNA, and most of the isolates (80.6%) were distributed within cluster A. Plasmids were detected in approximately 75% of the isolates, and seven different profiles were observed. Seventy-six percent (25/33) of the isolates carrying the plasmids were eliminated by 0.006% SDS incubated at 42℃, a sublethal condition. The occurrence of multidrug-resistant strains could be an indication of the excessive use of antibiotics in aquaculture farming. The rational use of antimicrobial agents and the surveillance of antibiotic administration may reduce the acquisition of resistance by microorganisms in aquatic ecosystems.

• Animal Bioscience
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• v.34 no.4
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• pp.734-742
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• 2021

Objective: The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential. Methods: A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex polymerase chain reaction-based assays using the specific primer sets. Results: A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%), and sen (28%), which were carried by 81% of S. saprophyticus. Conclusion: These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as staphylococcal cassette chromosome mec and tet(K).

• Food Science of Animal Resources
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• v.42 no.2
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• pp.225-239
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• 2022

As commensal colonizers in livestock, there has been little attention on staphylococci, especially non-aureus staphylococci (NAS), contaminating meat production chain. To assess prevalence of staphylococci in retail pork and slaughterhouse carcass samples in Korea, we collected 578 samples from Korean slaughterhouses (n=311) and retail markets (n=267) for isolation of staphylococci and determined antimicrobial resistance phenotypes in all the isolates. The presence of and prevalence of fusB-family genes (fusB, fusC, fusD, and fusF) and mutations in fusA genes were examined in fusidic acid resistant isolates. A total of 47 staphylococcal isolates of 4 different species (Staphylococcus aureus, n=4; S. hyicus, n=1; S. epidermidis, n=10; Mammaliicoccus sciuri, n=32) were isolated. Fusidic acid resistance were confirmed in 9/10 S. epidermidis and all of the 32 M. sciuri (previously S. sciuri) isolates. Acquired fusidic acid resistance genes were detected in all the resistant strains; fusB and fusC in S. epidermidis and fusB/C in M. sciuri. Multi-locus sequence type analysis revealed that ST63 (n=10, 31%) and ST30 (n=8, 25%) genotypes were most prevalent among fusidic acid resistant M. sciuri isolates. In conclusion, the high prevalence of fusB-family genes in S. epidermidis and M. sciuri strains isolated from pork indicated that NAS might act as a reservoir for fusidic acid resistance gene transmissions in pork production chains.

• Transactions on Electrical and Electronic Materials
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• v.5 no.5
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• pp.169-172
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• 2004

Deep sub-micron device required to get the superior ultra thin gate oxide characteristics. In this research, I will recommend a novel shallow trench isolation structure(STI) for thin gate oxide and a $N_2$O gate oxide 30 $\AA$ by NO ambient process. The local oxidation of silicon(LOCOS) isolation has been replaced by the shallow trench isolation which has less encroachment into the active device area. Also for $N_2$O gate oxide 30 $\AA$, ultra thin gate oxide 30 $\AA$ was formed by using the $N_2$O gate oxide formation method on STI structure and LOCOS structure. For the metal electrode and junction, TiSi$_2$ process was performed by RTP annealing at 850 $^{\circ}C$ for 29 sec. In the viewpoints of the physical characteristics of MOS capacitor, STI structure was confirmed by SEM. STI structure was expected to minimize the oxide loss at the channel edge. Also, STI structure is considered to decrease the threshold voltage, result in a lower Ti/TiN resistance( Ω /cont.) and higher capacitance-gate voltage(C- V) that made the STI structure more effective. In terms of the TDDB(sec) characteristics, the STI structure showed the stable value of 25 % ～ 90 % more than 55 sec. In brief, analysis of the ultra thin gate oxide 30 $\AA$ proved that STI isolation structure and salicidation process presented in this study. I could achieve improved electrical characteristics and reliability for deep submicron devices with 30 $\AA$ $N_2$O gate oxide.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.155-155
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• 2005

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2000.10a
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• pp.50.2-50
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• 2000

• The Plant Pathology Journal
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• v.17 no.4
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• pp.205-209
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• 2001

Dicarboximide-resistant isolates of Monilinia fructicola grew readily on media amended with dicarbosimide fungicides, and showed cross-resistance to pentachlo-ronitrobenzene (PCNB). The fitness of resistant isolates was inferior to that of sensitive isolates. Mycelial growth on fungicide-free medium was not significantly different between the dicarboximide-resistant and sensitive isolates. The originally high $\textrm{EC}_{50}$ values of the resistant isolate decreased after storage for 16 weeks at $4^{\circ}$. After inoculation with the mixture of spore suspensions of resistant and sensitive isolates, the re-isolation rate of the resistant spores was significantly reduced regardless of the mixing ratio. From the results, it could be concluded that the competitive ability of the resistant isolates is inferior to the sensitive ones.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.93-100
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• 2018

The aim of this study was to enhance the antioxidant activity of salted squid by inoculation of two Weissella spp. strains (W. cibaria FB-069 and W. viridescens FB-077) isolated from traditional Korea salted squid. The safety and probiotic potential characteristics of these two strains were evaluated. The safety of these strains was analyzed based on hemolytic activity, mucin degradation, biogenic amino production, and resistance to antibiotics. These lactic acid bacteria showed probiotic potential, including resistance to gastrointestinal tract conditions, adhesion to Caco-2 cells, and aggregation. The low-salted squid fermented with Weissella strains had consistently higher antioxidant activity through changing their amino acid profiles. Therefore, W. cibaria FB-069 and W. viridescens FB-077 might be good candidates for fermentation of salted squid to develop functional food with enhanced health benefits.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.743-751
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• 1991

This paper presents the 1.5\ulcorner PSA bipolar device which establishes the performance improvement such as the reduction of emitter resistance and substrate junction capacitance. To achieve the above electrical characteristics, RTA process and trench isolation technology were adapted. The emitter resistance and substrate capacitance of npn transistor having 1.5$[\times}6{\mu}m^{2}$emitter area was measured with 63$\Omega$and 28fF, respectively. The minimum propagation delay time shows 121ps at 0.7mW from the measurement of 31 stage ring oscillator.

• Mycobiology
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• v.30 no.2
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• pp.88-92
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• 2002

Rehmannia glutinosa is a perennial medicinal plant belonging to the family Scrophulariaceae with more than 300 species known in the world, especially in temperate regions. Its roots have been used widely in Korea for medicinal purposes. However, it is commonly infected by various pathogens during storage, causing great damage to the roots, and impedes the intensive farming of the crop. Therefore, an attempt has been made to isolate and screen a resistance gene against the pathogen Fusarium oxysporum using differential display. We treated salicylic acid(SA), and isolated a resistance gene that responds to SA. As a result, we found that SA was involved in plant defense mechanism in pathogenicity tests with SA treated and non-treted plants, and we isolated a partial PR-la gene through differential display polymerase chain reaction(DD-PCR) method.