• Journal of Microbiology and Biotechnology
• /
• 제31권2호
• /
• pp.280-289
• /
• 2021

Genetic markers currently used for the discrimination of Lactobacillus delbrueckii subspecies have low efficiency for identification at subspecies level. Therefore, our objective in this study was to select novel genetic markers for accurate identification and discrimination of six L. delbrueckii subspecies based on pangenome analysis. We evaluated L. delbrueckii genomes to avoid making incorrect conclusions in the process of selecting genetic markers due to mislabeled genomes. Genome analysis showed that two genomes of L. delbrueckii subspecies deposited at NCBI were misidentified. Based on these results, subspecies-specific genetic markers were selected by comparing the core and pangenomes. Genetic markers were confirmed to be specific for 59,196,562 genome sequences via in silico analysis. They were found in all strains of the same subspecies, but not in other subspecies or bacterial strains. These genetic markers also could be used to accurately identify genomes at the subspecies level for genomes known at the species level. A real-time PCR method for detecting three main subspecies (L. delbrueckii subsp. delbrueckii, lactis, and bulgaricus) was developed to cost-effectively identify them using genetic markers. Results showed 100% specificity for each subspecies. These genetic markers could differentiate each subspecies from 44 other lactic acid bacteria. This real-time PCR method was then applied to monitor 26 probiotics and dairy products. It was also used to identify 64 unknown strains isolated from raw milk samples and dairy products. Results confirmed that unknown isolates and subspecies contained in the product could be accurately identified using this real-time PCR method.

• Animal Systematics, Evolution and Diversity
• /
• 제26권1호
• /
• pp.15-19
• /
• 2010

The Russian ratsnake, Elaphe schrenckii, is found in Russia, China, and Korea, and is considered to be an endangered species by the Ministry of Environment in South Korea. Due to habitat loss and use in oriental medicine, their population has been severely decimated. In South Korea, two subspecies of E. schrenckii has been defined according to body color: E. s. schrenckii (blackish) and E. s. anomala (yellow-brownish). Molecular genetic studies on Elaphe schrenckii are very scarce and the taxonomy of Elaphe schrenckii subspecies is uncertain. From the present study, we attempted to identify the genetic differences of these two subspecies using species-specific microsatellites developed from the genomic library of E. schrenckii. Nine polymorphic loci were tested on 19 individuals from E. s. schrenckii (n=10) and E. s. anomala (n=9) in South Korea. The mean number of alleles was 3.78 in E. s. schrenckii and 4.11 in E. s. anomala. The average expected heterozygosity was 0.542 and 0.511 in E. s. schrenckii and E. s. anomala, respectively. We found a lack of genetic structure between two subspecies ($F_{ST}=0.016$) and no genetic discrimination between two subspecies was found. Based on the present findings by microsatellites, two subspecies can be considered as one species, E. schrenckii. However, further investigations on taxonomical status using mitochondrial and nuclear DNA sequences need to be performed and morphological & ecological data should be revised. The genetic markers should benefit future studies of the endangered species of other Elaphe species for the study of genetic diversity and potential conservation management.

• Mass Spectrometry Letters
• /
• 제5권4호
• /
• pp.110-114
• /
• 2014

The method of direct mass spectrometry profiling is reliable and reproducible for the rapid identification of clinical isolates of bacteria and fungi. This is the first study evaluating the approach of MALDI-TOF mass spectrometry profiling for rapid identification of carbapenemase-resistant enterobacteriaceae (CRE). Proof of concept was achieved by the discrimination of CRE using MALDI Biotyper MS based on the protein. This profiling appears promising by the visual observation of consistent unique peaks, albeit low intensity, that could be picked up from the mean spectra (MSP) method. The Biotyper MSP creation and identification methods needed to be optimized to provide significantly improved differences in scores to allow for subspecies identification with and without carbapenemases. These spectra were subjected to visual peak picking and in all cases; there were pertinent differences in the presence or absence of potential biomarker peaks to differentiate isolates. We also evaluated this method for potential discrimination between different carbapenemases bacteria, utilizing the same strategy. Based on our data and pending further investigation in other CREs, MALDI-TOF MS has potential as a diagnostic tool for the rapid identification of even closely related carbapenemases but would require a paradigm shift in which Biotyper suppliers enable more flexible software control of mass spectral profiling methods.

• Journal of Microbiology and Biotechnology
• /
• 제11권5호
• /
• pp.788-797
• /
• 2001

The usefulness of three PCR methods were evaluated for the epidemiological typing of Staphylococcus aureus: an enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), repetitive extragenic palindromic element PCR (REP-PCR), and 16S-23S intergenic spacer PCR (ITS-PCR). The analysis was performed using a collection of S. aureus strains comprised of 6 reference and 79 isolates from patients with various diseases. Among the 85 S. aureus strains tested, 6 references and 6 isolates were found to be susceptible to methicillin, whereas the remaining 73 isolates were resistant to it. PCR methods are of special concern, as conventional phenotypic methods are unable to clearly distinguish among methicillin-resistant S. aureus (MRSA) strains. The ability of the techniques to detect different unrelated types was found to be as follows: ERIC-PCR, 19 types; REP-PCR, 36 types; and ITS-PCR, 14 types. On the basis of combining the ERIC, REP, and ITS fingerprints, the 85 S. aureus strains were grouped into 56 genetic types (designated G1 to G56). The diversities for the 85 S. aureus strains, calculated according to Simpson\`s index, were 0.88 for an ERIC-PCR, 0.93 for a REP-PCR, and 0.48 for an ITS-PCR, and the diversity increased up to 0.97 when an ERIC-PCR and REP-PCR were combined. The above discrimination indices imply that the genetic heterogeneity of S. aureus strains is high. Accordingly, this study demonstrates that DNA sequences from highly conserved repeats of a genome, particularly a combination of ERIC sequences and REP elements, are a convenient and accurate tool for the subspecies-specific discrimination and epidemiologic tracking of S. aureus.

• 대한수의학회지
• /
• 제43권1호
• /
• pp.77-86
• /
• 2003

Pullorum disease due to Salmonella enterica subspecies enterica bioserovar Pullorum (S. pullorum) is reported to be an endemic disease in domestic poultry flocks. The pulsed-field gel electrophoresis (PFGE) subtyping method was used to assess the extent of genetic diversity and clonality of most of salmonella serotypes and other diverse bacterial species from animals and environmental samples in worldwide. Nowadays, PFGE has already been evaluated as a gold standards for molecular subtyping of salmonella serotypes compared with other molecular analysis methods. PFGE of XbaI digested chromosomal DNA from 23 strains of S. pullorum gave 5 distinctive pulsotypes (from SXPI to SXPV) with 5% confidence range of Dice coefficients, indicating that PFGE is very discriminative and that multiple clones of S. pullorum have been existed and diffused all of domestic poultry flocks industries since 1995. Two dominant pulsogroups (SXA & SXB) appeared as a major clones in this country, because they had consistently been recovered from diverse sources including both chicken organs and raw feed materials between 1995 and 1998. In addition, the matching percentage of PFGE profiles (PFP) among strains from both chickens and feed ingredients provides indirect evidence of the possible transmission of pullorum disease from contaminated raw feed ingredients for chicken production. In calculating of discrimination index (DI) for PFGE method by Simpson's index, DI was appeared as 0.917. Therefore, this index suggested that the present PFGE would seem to be a desirable and confident molecular typing method for S. pullorum strains. To our knowledge for pullorum disease, this is the first study to compare S. pullorum strains from chicken organs and feed samples using the PFGE.

• 한국응용곤충학회지
• /
• 제61권3호
• /
• pp.399-408
• /
• 2022

새롭게 육성된 낭충봉아부패병 저항성 신품종 토종벌(Apis cerana koreana) 과 기존 농가에서 관행적으로 사육되는 토종벌 사이의 형태학적 차이를 육안으로 확연하게 구분하는 것은 어렵지만 본 연구에서는 신품종 토종벌(A. c. koreana) 을 기존 토종벌(A. c. koreana) 품종 및 계통 간 형태학적 비교를 통해 신품종 만의 특성을 결정할 수 있는 표현형 정보를 제공하였다. 신품종 토종벌(A. c. koreana)의 외부형질을 이용한 품종 특성은 22가지의 형태학적 특성을 기하학적, 형태학적 분석 방법을 적용하고 토종벌(A. c. koreana)의 로얄젤리 생산량, 일벌, 여왕벌, 수벌의 특성을 비교 분석하였다. 본 연구 결과, 신품종 토종벌(A. c. koreana)은 기존 토종벌과 앞날개의 길이에 차이를 보였으며, 중국의 동양종꿀벌(A. cerana)과 비교한 결과, 일벌은 몸무게, 혀의 길이, 앞날개의 길이 등의 값이 높았다. 또한, 신품종 토종벌(A. c. koreana)은 A. cerana indica 보다 두 가지 부위에서 형태학적인 차이를 보였다. 그리고 신품종 토종벌(A. c. koreana)은 로얄젤리를 다른 품종과 비교하여 많이 분비하여 봉군의 발육에 긍정적인 영향을 끼쳤다. 따라서 본 연구결과는 신규 육성 토종벌(A. cerana)에 대한 형태학적 분석 방법을 이용하여 품종을 분류하는데 도움이 될 것으로 기대한다.

• 한국축산식품학회지
• /
• 제28권3호
• /
• pp.276-282
• /
• 2008

우리나라는 전 세계 녹용의 약 80% 이상을 소비하고 있는 양록 대국이나 최근 국내 녹용시장에서의 녹용 둔갑판매 및 불법유통 현상이 문제점으로 대두되고 있다. 따라서 본 연구는 녹용의 종 감별 기술을 개발하고자 현재 국내에서 유통되고 있는 러시아산 원용, 북미산 대록, 국산화용, 중국산 깔깔이 및 알래스카산 순록 등 5종의 대표적인 녹용들을 대상으로 종간 염기서열 변이성이 매우 높은 유전자로 알려져 있는 mt DNA내 cytochrome b 및 D-loop 유전자 영역의 염기서열 분석 및 종간 변이성 비교분석을 수행하였다. 각 녹용시료에서 mt DNA를 분리하고 cytochrome b와 D-loop유전자의 특정 영역을 포함하는 primer를 설계 합성하고 PCR로 증폭한 후 DNA 증폭산물의 염기서열을 분석하여 종간 유전정보의 동일성 여부를 비교한 결과 녹용 종간에 명확한 차이를 보이는 염기서열 부위가 검출되었고 이러한 종간 염기배열 차이에 근거하여 녹용의 종 감별이 가능하였다. 또한, mt DNA cytochrome b유전자에서 종간 특이적 염기서열을 인지하는 두 종류의 제한효소(NlaIV 및 TaqI)을 이용한 PCR-RFLP 기법으로 녹용으로 인정되지 않는 순록의 종 특이적 RFLP 분자표지를 검출하였고 이를 이용하여 녹용과 순록간의 종 판별이 가능하였다. 한편, D-loop 유전자의 특정 영역 염기서열 분석기법을 이용하여 시중에서 러시아산 원용으로 유통되고 있는 녹용 절편 32개를 무작위표본 추출하여 녹용의 종 감별을 조사한 결과 러시아산 원용으로 인정되는 것은 62.5%에 불과하였고 나머지는 중국산 마록(25.0%)과 엘크 및 순록의 아종으로 추정되는 시료도 일부 검출되었다. 따라서 본 연구를 통해 사슴 녹용 mt DNA 유전자의 염기서열 유전정보 변이 차이를 이용한 염기서열 분석법과 특정 제한효소(NlaIV 및 TaqI)를 이용한 PCR-RFLP 기법은 녹용의 과학적인 종 감별과 이를 바탕으로 녹용 원산지의 추정도 가능할 것으로 기대된다.