• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.575-584
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• 2012

Listeria monocytogenes is an important foodborne pathogen that comprises four genetic lineages: I, II, III, and IV. Of these, lineage II is frequently recovered from foods and environments and responsible for the increasing incidence of human listeriosis. In this study, the phylogenetic structure of lineage II was determined through sequencing analysis of the ascB-dapE internalin cluster. Fifteen sequence types proposed by multilocus sequence typing based on nine housekeeping genes were grouped into three distinct sublineages, IIA, IIB, and IIC. Organization of the ascB-dapE internalin cluster could serve as a molecular marker for these sublineages, with inlGHE, inlGC2DE, and inlC2DE for IIA, IIB, and IIC, respectively. These sublineages displayed specific genetic and phenotypic characteristics. IIA and IIC showed a higher frequency of recombination (${\rho}/{\theta}$). However, recombination events had greater effect (r/m) on IIB, leading to its high nucleotide diversity. Moreover, IIA and IIB harbored a wider range of internalin and stress-response genes, and possessed higher nisin tolerance, whereas IIC contained the largest portion of low-virulent strains owing to premature stop codons in inlA. The results of this study indicate that IIA, IIB, and IIC might occupy different ecological niches, and IIB might have a better adaptation to a broad range of environmental niches.

• Animal cells and systems
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• 제7권2호
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• pp.139-144
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• 2003

We analyzed seven Y chromosome binary markers (YAP, RPS4Y_711,\;M9,\;M175,\;LINE1,\;SRY_+465$ and 47z) in samples from a total of 254 males from Koreans and tow Mongolian ethnic groups (Buryat and Khalkh) to study the genetic relationship among these populations. We found eight distinct Y haplogroups constructed from the seven binary markers. Haplogroup DE-YAP was present at extremely low frequencies (∼2%) in the Korean and Mongolian populations. This result is consistent with earlier reports that showed the YAP+ chromosomes to be highly polymorphic only in populations from Japan and Tibet in east Asia. The observed high frequency of haplogroup $C-RPS4Y_711$ in the Mongolian populations (∼40%) is concordant with recent findings, showing that the $RPS4Y_711$-T chromosomes were distributed at high frequencies in Siberian and Mongolian populations compared with most other populations from east Asia. Thus, the relatively moderate frequency of haplogroup $C-RPS4Y_711$ in Korean (∼15%) can be seen as genetic evidence for probable interaction with Mongolian and/or Siberian populations. In contrast, the majority (∼75%) of modern Koreans studied here had high frequencies of Y chromosome lineages of haplogroup O-M175 and additional haplogroupts that define sublineage of O-M175, which are most likely related with modern populations in China. In conclusion, our data on the Y chromosome haplogroup distribution may provide evidence for interaction between Korean and Mongolian populations, but Korean tend to be much more related with those from southern-to-northern populations of China than to Mongolians in east Asia.

• 한국가금학회지
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• 제38권2호
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• pp.89-96
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• 2011

몽골 산란계 농장에서 발생한 뉴캣슬병 사례로부터 뉴캣슬병 바이러스를 분리하고 그 특성을 조사하였다. 그 결과, 발생 농장 산란계 폐사계의 뇌 및 폐 조직으로부터 뉴캣슬병 바이러스 MN1/10 주가 분리되었다. 이 바이러스는 F 단백질 분절 부위가 특징적인 병원성 motif(RRQKRF)를 가지고 있었으며 종란 평균 치사 지수(MDT)가 54.7시간으로 강독형 NDV이었다. 또한 발생 농장 내 생존하고 있는 산란계에서 고역가의 NDV 특이항체가 검출되었다. 유적학적 계통 분석을 실시한 결과, 몽골 분리주는 Class II에 속하는 genotype VIId 바이러스로 확인되었다. 유전학적 계통 분석 결과, 몽골 분리주는 몽골과 인접한 중국에서 유행하는 바이러스 그룹(CN2)에 속하는 것으로 분류되었다. 우리의 연구 결과는 몽골에서의 뉴캣슬병 최초 발생은 동북아시아 지역에서 유행하는 강독형 NDV의 유입에 의해서 이루어졌음을 말해 준다.

• 한국가금학회지
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• 제46권3호
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• pp.173-183
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• 2019

조류인플루엔자 바이러스 H7 subtype에 속하는 바이러스 중 일부는 가금류에 감염할 경우 고병원성이 발휘된다. 또 H7 아형 AIV중 일부는 사람에 감염하여 사망 등을 유발할 수도 있다. 본 연구는 야생조류로부터 분리된 H7 아형 조류인플루엔자 바이러스 6주(H7N7 아형 4주, H7N1 아형 2주)를 대상으로 8개 유전자 분절 전체의 염기서열을 분석하여 병원성, 사람 감염 가능성 등 그 특성을 조사하였다. 계통유전학적 분석결과, 국내에서 분리된 H7 아형 분리주들은 8개 유전자(HA, NA, PB2, PB1, PA, NP, M, NS) 모두 Eurasian lineage로 분류되었으나, Eurasian lineage 내에서도 각기 다른 sublineage로 분류되어 유전적 다양성이 있는 것으로 분석되었다. 한국 분리주 6주는 HA 단백질 분절부위 아미노산은 두 종류(PEIPKGR 및 PELPKGR)의 motif를 가지고 있었으나, 모두 저병원성 바이러스 특성을 가지고 있었다. 숙주세포 결합 특이성과 관련 있는 HA 단백질 receptor-binding site를 분석한 결과, 한국 분리주 모두는 사람 세포 수용체 결합특이성보다는 조류 세포 수용체 결합 특이성을 가지는 것으로 나타났다. 사람 감염 가능성을 높게 하는 부위에서의 아미노산 치환(PB2 단백질의 E627K 및 PB1단백질의 I368V)도 나타나지 않았고, 또한 NA stalk region에서의 결손도 관찰되지 않았다. 이상의 결과를 미루어 볼 때 한국 야생조류에서 분리된 H7 아형 6주 모두는 저병원성 바이러스로 최근 중국에서 사람 감염이 나타나고 있는 H7N9 바이러스와는 유전적으로 다른 계열의 바이러스인 것으로 판단된다.

• Biomolecules & Therapeutics
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• 제32권4호
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• pp.481-491
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• 2024

Paxlovid is the first approved oral treatment for coronavirus disease 2019 and includes nirmatrelvir, a protease inhibitor targeting the main protease (M^pro) of SARS-CoV-2, as one of the key components. While some specific mutations emerged in M^pro were revealed to significantly reduce viral susceptibility to nirmatrelvir in vitro, there is no report regarding resistance to nirmatrelvir in patients and animal models for SARS-CoV-2 infection yet. We recently developed xenograft tumors derived from Calu-3 cells in immunodeficient mice and demonstrated extended replication of SARS-CoV-2 in the tumors. In this study, we investigated the effect of nirmatrelvir administration on SARS-CoV-2 replication. Treatment with nirmatrelvir after virus infection significantly reduced the replication of the parental SARS-CoV-2 and SARS-CoV-2 Omicron at 5 days post-infection (dpi). However, the virus titers were completely recovered at the time points of 15 and 30 dpi. The virus genomes in the tumors at 30 dpi were analyzed to investigate whether nirmatrelvir-resistant mutant viruses had emerged during the extended replication of SARS-CoV-2. Various mutations in several genes including ORF1ab, ORF3a, ORF7a, ORF7b, ORF8, and N occurred in the SARS-CoV-2 genome; however, no mutations were induced in the M^pro sequence by a single round of nirmatrelvir treatment, and none were observed even after two rounds of treatment. The parental SARS-CoV-2 and its sublineage isolates showed similar IC₅₀ values of nirmatrelvir in Vero E6 cells. Therefore, it is probable that inducing viral resistance to nirmatrelvir in vivo is challenging differently from in vitro passage.