• Parasites, Hosts and Diseases
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• 제56권6호
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• pp.589-596
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• 2018

Ticks are the vectors of various pathogens, threatening human health and animal production across the globe. Here, for the first time we detected Ricketssia spp., Borrelia spp. and protozoan in ticks from Poyang Lake region in Jiangxi Province of eastern China. In 3 habitat categories and on 12 host species, 311 ticks from 11 species were collected. Haemaphysalis longicornis was the predominant species, accounting for 55.63%, followed by Rhipicephalus microplus, Haemaphysalis flava and Ixodes granulatus. Of the collected ticks, 7.07% were positive for tick-borne pathogens, and H. longicornis and H. flava were found to be co-infected with Ricketssia spp. and protozoan. H. flava was the most detected positive for tick-borne pathogens, whereas H. longicornis had the lowest infection rate, and the difference in infection rates between tick species was significant (${\chi}^2=61.24$, P<0.001). Furthermore, adult ticks demonstrated remarkably greater infection rate than immature ticks (${\chi}^2=10.12$, P=0.018), meanwhile ticks on Erinaceidae showed significantly higher positivity than ticks collected on other host species (${\chi}^2=108.44$, P<0.001). Genetic fragment sequencing and analyses showed at least 4 pathogen species presence in ticks, namely Borrelia yangtzensis, Rickettsia slovaca or Rickettsia raoultii related genospecies, Babesia vogeli and Hepatozoon canis or Hepatozoon felis related genospecies. The finding indicates that the abundant ticks can carry diverse pathogens in Poyang Lake region, and pathogen infection is highly related to species, vertebrate hosts and life stages of ticks.

• Journal of Plant Biotechnology
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• 제49권1호
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• pp.46-60
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• 2022

The genetic variability and population structure of apple mosaic virus (ApMV) have been studied; however, synonymous codon usage patterns influencing the survival rates and fitness of ApMV have not been reported. Based on phylogenetic analyses of 52 ApMV coat protein (CP) sequences obtained from apple, pear, and hazelnut, ApMV isolates were clustered into two groups. High molecular diversity in GII may indicate their recent expansion. A constant and conserved genomic composition of the CP sequences was inferred from the low codon usage bias. Nucleotide composition and relative synonymous codon usage (RSCU) analysis indicated that the ApMV CP gene is AU-rich, but G- and U-ending codons are favored while coding amino acids. This unequal use of nucleotides together with parity rule 2 and the effective number of codon (ENC) plots indicate that mutation pressure together with natural selection drives codon usage patterns in the CP gene. However, in this combination, selection pressure plays a more crucial role. Based on principal component analysis plots, ApMV seems to have originated from apple trees in Europe. However, according to the relative codon deoptimization index and codon adaptation index (CAI) analyses, ApMV exhibited the greatest fitness to hazelnut. As inferred from the results of the similarity index analysis, hazelnut has a major role in shaping ApMV RSCU patterns, which is consistent with the CAI analysis results. This study contributes to the understanding of plant virus evolution, reveals novel information about ApMV evolutionary fitness, and helps find better ApMV management strategies.

• 한국컴퓨터정보학회논문지
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• 제27권11호
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• pp.295-304
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• 2022

본 연구의 목적은 라이브방송 전자상거래 플랫폼의 특성과 생방송 사업자의 개인적 특성이 생방송 시청자의 충동구매의도에 영향을 미치는 요인과 메커니즘을 규명하는 것이다. 본 연구는 ELM 모델을 기반으로 기존의 미흡한 내용을 심층적으로 조사하고자 한다. 본 연구는 온라인 생방송 이용자를 대상으로 설문조사 형식을 채택하고 SPSS, AMOS, Mplus 등의 분석 소프트웨어를 이용하여 실증분석을 수행하였다. 그 결과, 생방송 플랫폼의 특성은 소비자의 몰입 경험과 만족도에 의미 있는 영향을 미치고, 앵커의 개인적 특성은 소비자의 몰입 경험과 만족도에 의미 있는 영향을 미치고, 소비자의 몰입 경험과 만족도는 의미 있는 영향을 미치는 것으로 나타났다. 충동 구매 의도는 의미 있는 영향을 미치고 몰입경험과 만족도는 생방송플랫폼의 특성과 진행자의 개인적 특성에 매개효과가 있다.

• 한국ITS학회 논문지
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• 제21권3호
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• pp.73-82
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• 2022

자율주행 시스템의 수용성 보장은 중요하다. 시스템 수용성 요소 중 하나인 자율주행 종방향 제어기는 상위 제어기와 하위 제어기로 구성된다. 상위 제어기는 Cruise 제어와 Space 제어를 상황에 맞는 제어를 결정하고 필요한 목표 속도를 만든다. 하위 제어기에서는 목표 속도를 추종하기 위한 가속도 신호를 만들어서 제어를 수행한다. 본 논문에서는 상위 제어기에서 Cruise 제어와 Space 제어전환 문제에서 발생하는 차간거리 변동을 개선하는 알고리즘을 제안한다. 제안한 방법은 Cruise 제어에서 Space 제어로 전환되는 시점에 Cruise 제어에 Approach 알고리즘을 추가하여 전환 거리에서 Space 제어로 전환되도록 하는 것이다. 이를 통해서 ± 12m 초기 오차에서 ±4m까지 오차를 개선했으며 실차검증을 수행하였다.

• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.329-338
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• 2023

Enterohemorrhagic Escherichia coli (EHEC) is a foodborne pathogen that produces attaching and effacing lesions on the large intestine and causes hemorrhagic colitis. It is primarily transmitted through the consumption of contaminated meat or fresh produce. Similar to other bacterial pathogens, antibiotic resistance is of concern for EHEC. Furthermore, since the production of Shiga toxin by this pathogen is enhanced after antibiotic treatment, alternative agents that control EHEC are necessary. This study aimed to discover alternative treatments that target virulence factors and reduce EHEC toxicity. The locus of enterocyte effacement (LEE) is essential for EHEC attachment to host cells and virulence, and most of the LEE genes are positively regulated by the transcriptional regulator, Ler. GrlA protein, a transcriptional activator of ler, is thus a potential target for virulence inhibitors of EHEC. To identify the GrlA inhibitors, an in vivo high-throughput screening (HTS) system consisting of a GrlA-expressing plasmid and a reporter plasmid was constructed. Since the reporter luminescence gene was fused to the ler promoter, the bioluminescence would decrease if inhibitors affected the GrlA. By screening 8,201 compounds from the Korea Chemical Bank, we identified a novel GrlA inhibitor named Grlactin [3-[(2,4-dichlorophenoxy)methyl]-4-(3-methylbut-2-en-1-yl)-4,5-dihydro-1,2,4-oxadiazol-5-one], which suppresses the expression of LEE genes. Grlactin significantly diminished the adhesion of EHEC strain EDL933 to human epithelial cells without inhibiting bacterial growth. These findings suggest that the developed screening system was effective at identifying GrlA inhibitors, and Grlactin has potential for use as a novel anti-adhesion agent for EHEC while reducing the incidence of resistance.

• 한국미생물·생명공학회지
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• 제51권4호
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• pp.390-402
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• 2023

Salmonella are Gram-negative pathogenic bacteria commonly found in food animals such as poultry and swine and potentially constitute risks and threats to food safety and public health through transmissible virulence and antimicrobial resistance (AMR) genes. Although there are previous studies in the Philippines regarding genotypic and phenotypic AMR in Salmonella, there are very few on virulence and their associations. Hence, this study collected 700 Salmonella isolates from swine samples in abattoirs and wet markets among four districts in Metro Manila and characterized their genotypic virulence and β-lactam AMR profiles. Gene frequency patterns and statistical associations between virulence and bla genes and comparisons based on location types (abattoirs and wet markets) and districts were also determined. High prevalence (>50%) of virulence genes was detected encompassing Salmonella pathogenicity islands (SPIs) 1-5 suggesting their pathogenic potential, but none possessed plasmid-borne virulence genes spvR and spvC. For bla, bla_TEM was detected with high prevalence (>45%) and revealed significant associations to four SPI genes, namely, avrA, hilA, mgtC, and spi4R, which suggest high resistance potential particularly to β-lactam antibiotics and relationships with pathogenicity that remain mechanistically unestablished until now. Lastly, comparisons of location types and districts showed variations in gene prevalence suggesting effects from environmental factors throughout the swine production chain. This study provides vital data on the genotypic virulence and AMR of Salmonella from swine in abattoirs and wet markets that suggest their pathogenicity and resistance potential for policymakers to implement enforced surveillance and regulations for the improvement of the Philippine swine industry.

• Journal of Microbiology and Biotechnology
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• 제7권5호
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• pp.352-355
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• 1997

The promoter region of the pupA gene of Pseudomonas putida WCS358 was fused with the structural genes for bioluminescence (luxCDABE) from Vibrio fischeri, and the resulting fusion plasmid harbored by the WCS358 host. The pup-lux fusion gene was then used for quantitative analysis of the iron-dependence of pupA promoter activity. Factors affecting bioluminescence produced by the pup-lux bioreporter were found to be cell activity, iron-chelator concentrations, Fe(III) concentrations, and nutrient components. Light production rates of the pup-lux bioreporter were inversely dependent upon iron molecules when $FeCl_3$ concentrations were between $10^{-2}$ and 1 ${\mu}M$ in nutrient-poor minimal media, and between 0.1 and 10 mM in nutrient-rich complex media.

• Child Studies in Asia-Pacific Contexts
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• 제6권1호
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• pp.17-29
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• 2016

To help define future research direction and enhance educational service for children from Asian and Latino immigrant backgrounds, this review examines research investigating social competence with reference to host and heritage language skills. A targeted search obtained 14 peer-reviewed studies published from 1994 to 2014 focusing on children aged from birth to 12 years. Social competence is mainly measured by four dimensions: externalizing behaviours, internalizing behaviours, social skills and relationships with others. The evidence suggests that English proficiency levels are positively associated with social skills and parent-child relationships are of higher quality when parent-child heritage language difference is minimal. However the findings are mixed regarding how English levels are associated with externalizing, internalizing behaviours and relationships with others and how heritage language levels are associated with social competence. This review makes a set of recommendations for future research including assessment of participants' language proficiency with language tests and examination of emotional factors in the relationship between English and social competence. The implications of the findings are also discussed for educators.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.125.1-125
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• 2003

Pepper anthracnose is one of the major limiting factors in pepper production. Boring last over 10 years, Colletotrichum gloeosporioides has been known as the most prevalent species among five Colletotrichum spp. involved as anthracnose causing agents. Recently, however, the change of major species with pepper anthracnose has been proposed. Identification study was peformed on 12 test isolates collected from anthracnose disease symptoms on pepper during 2001-2002 and 25 reference isolates obtained from several other host plants. The identification of the isolates with morphological observation and IfS region sequence comparison resulted that 11 ones from 12 test isolates colleted from pepper anthracnose during 2001-2002 were identified as C. acutatum. PCR using species-specific primers designed from ITS region sequence suggested a rapid diagnosis method in identifying C. acutatum from C. gloeosporioides.

• Tuberculosis and Respiratory Diseases
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• 제79권4호
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• pp.201-206
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• 2016

Active tuberculosis (TB) has a greater burden of TB bacilli than latent TB and acts as an infection source for contacts. Latent tuberculosis infection (LTBI) is the state in which humans are infected with Mycobacterium tuberculosis without any clinical symptoms, radiological abnormality, or microbiological evidence. TB is transmissible by respiratory droplet nucleus of $1-5{\mu}m$ in diameter, containing 1-10 TB bacilli. TB transmission is affected by the strength of the infectious source, infectiousness of TB bacilli, immunoresistance of the host, environmental stresses, and biosocial factors. Infection controls to reduce TB transmission consist of managerial activities, administrative control, engineering control, environmental control, and personal protective equipment provision. However, diagnosis and treatment for LTBI as a national TB control program is an important strategy on the precondition that active TB is not missed. Therefore, more concrete evidences for LTBI management based on clinical and public perspectives are needed.