• Journal of Ginseng Research
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• 제40권2호
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• pp.176-184
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• 2016

Background: Wild ginseng, Panax ginseng Meyer, is an endangered species of medicinal plants. In the present study, we analyzed variations within the ribosomal DNA (rDNA) cluster to gain insight into the genetic diversity of the Oriental ginseng, P. ginseng, at artificial plant cultivation. Methods: The roots of wild P. ginseng plants were sampled from a nonprotected natural population of the Russian Far East. The slides were prepared from leaf tissues using the squash technique for cytogenetic analysis. The 18S rDNA sequences were cloned and sequenced. The distribution of nucleotide diversity, recombination events, and interspecific phylogenies for the total 18S rDNA sequence data set was also examined. Results: In mesophyll cells, mononucleolar nuclei were estimated to be dominant (75.7%), while the remaining nuclei contained two to four nucleoli. Among the analyzed 18S rDNA clones, 20% were identical to the 18S rDNA sequence of P. ginseng from Japan, and other clones differed in one to six substitutions. The nucleotide polymorphism was more expressed at the positions 440-640 bp, and distributed in variable regions, expansion segments, and conservative elements of core structure. The phylogenetic analysis confirmed conspecificity of ginseng plants cultivated in different regions, with two fixed mutations between P. ginseng and other species. Conclusion: This study identified the evidences of the intragenomic nucleotide polymorphism in the 18S rDNA sequences of P. ginseng. These data suggest that, in cultivated plants, the observed genome instability may influence the synthesis of biologically active compounds, which are widely used in traditional medicine.

• 한국양식학회지
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• 제21권3호
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• pp.139-145
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• 2008

성게의 형태학적 분류는 그것의 형질적 변이에 의하여 어려움이 많다. 본 연구에서는 말똥성게, 둥근성게, 보라성게, 분홍성게와 동해안에서 포획된 미확인 성게 4종의 형태형질 비교와 계통유연관계를 조사하였다. 성게의 생식소로부터 genomic DNA를 분리한 후, PCR 방법을 통하여 mitochondrial 12S rDNA 유전자의 염기서열을 분석하였다. 둥근성게과의 말똥성게, 둥근성게, 만두성게과의 보라성게, 주발성게과의 분홍성게의 mitochondrial 12S rDNA의 염기서열은 미확인 성게종들의 그것과 85.9-93.9%의 상동성을 나타내었다. 한편, 미확인 성게종들은 새치성게의 mitochondrial 12S rDNA의 일부 염기서열과 99.8%의 높은 상동성을 보였으며, 각 개체의 mitochondrial 12S rDNA를 통한 분자계통수 분석에 의해서 미확인 성게들은 새치성게의 형태적 변이로 판단된다.

• 한국어병학회지
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• 제23권3호
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• pp.313-322
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• 2010

Edible tunicate Halocynthia roretzi, one of the most commercially important aquatic organisms in Korea, has been killed by tunic softness syndrome since last decade. The intracellular protistan parasite observed by the transmission electron microscope in hemocytes of the tunicate was considered to be the causative agent of the mass mortality. The goal of the present work is to examine the characteristic features of the parasite by identifying the 18S rDNA sequences of the parasite. The experiments conducted include amplification of presumptive 18S rDNA from diseased tunicate tissues with UNonMet-PCR and sequencing the product. A preliminary phylogenetic analysis was performed on the presumptive parasite rDNA. A digoxigenin labeled DNA probe was designed on the basis of the sequences of rDNA. Dig-ISH assay was conducted to diagnose the protistan parasite. A PCR using UNonMet-PCR primer generated 595 bp SSU rDNA fragment. Subsequently, PCRs with primer pair expended this sequence to 1542 bp. This is the first partial sequences of SSU rDNA gene to be published on the protistan parasite that has presumed causing the mass mortality of tunicate. Since the Dig-ISH technique demonstrated the presence of infection in hemocytes on the all host tissues, the fragment was confirmed to be the intracellular protistan parasite SSU rDNA. A phylogenetic analysis suggested that the protistan parasite may be a unique eukaryote that is closely related to Apicomplexa.

• The Plant Pathology Journal
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• 제40권2호
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• pp.171-191
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• 2024

Identification of Helicotylenchus species is very challenging due to phenotypic plasticity and existence of cryptic species complexes. Recently, the use of rDNA barcodes has proven to be useful for identification of Helicotylenchus. Molecular markers are a quick diagnostic tool and are crucial for discriminating related species and resolving cryptic species complexes within this speciose genus. However, DNA barcoding is not an error-free approach. The public databases appear to be marred by incorrect sequences, arising from sequencing errors, mislabeling, and misidentifications. Herein, we provide a comprehensive analysis of the newly obtained, and published DNA sequences of Helicotylenchus, revealing the potential faults in the available DNA barcodes. A total of 97 sequences (25 nearly full-length 18S-rRNA, 12 partial 28S-rRNA, 16 partial internal transcribed spacer [ITS]-rRNA, and 44 partial cytochrome c oxidase subunit I [COI] gene sequences) were newly obtained in the present study. Phylogenetic relationships between species are given as inferred from the analyses of 103 sequences of 18S-rRNA, 469 sequences of 28S-rRNA, 183 sequences of ITS-rRNA, and 63 sequences of COI. Remarks on suggested corrections of published accessions in GenBank database are given. Additionally, COI gene sequences of H. dihystera, H. asiaticus and the contentious H. microlobus are provided herein for the first time. Similar to rDNA gene analyses, the COI sequences support the genetic distinctness and validity of H. microlobus. DNA barcodes from type material are needed for resolving the taxonomic status of the unresolved taxonomic groups within the genus.

• 미생물학회지
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• 제43권3호
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• pp.179-185
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• 2007

본 연구는 polymerase chanin reaction(PCR)기법과 DNA enzyme-linked immunosorbent assay(DNA ELISA) 기법을 이용하여 토양내 식물병원균인 Ralstonia solanacearum를 검출하고자 하였다. 토양 시료로부터 분석에 사용될 R. solanacearum DNA를 추출하기 위하여 몇 가지 방법을 비교 평가한 결과 기존의 DNA 추출 방법에 비하여 Guanidin isothiocyanate와 Chelex-100 resin을 사용하는 방법 이 토양 내에 존재하는 다양한 중류의 반응 저해 물질과 R. solanacearum만의 고유한 PCR반응 저해물질들을 제거하는 데에 효과적이었다. R. solanacearum만을 특이적으로 검출하기 위해 fliC유전자 부위에 특이적인 몇 종의 primer들을 제작하였다. 이들 중 높은 민감도와 특이도를 나타내는 두 set의 primer RsolfliC(forward; 5-GAACGCCAACGGTGCGAACT-3 and reverse; 5-GGCGGCCTTCAGGGAGGTC-3, designed by J. $Sch\ddot{o}nfeld$ et al.)와 RS_247 (forward; 5-GGCGGTCTGTCGGCRG-3 and reverse; 5-CGGTCGCGTTGGCAAC-3, designed by this study)를 선정하여 nested PCR을 수행할 수 있도록 고안하였다. Nested PCR primer에 biotin을 표지하였고 nested PCR산물의 내부 서열과 특이적으로 교잡반응을 할 수 있는 probe를 제작하여 PCR 결과를 DNA-EIA반응으로 확인 분석할 수 있도록 하였다. Primary PCR과 nested PCR의 산물을 전기영동 상에서 확인한 결과, nested PCR이 약 $10^2$정도의 높은 민감도를 나타내었고 DNA-EIA의 경우 $10^2P{\sim}10^3$정도의 민감도를 상승시켜주는 것으로 확인되었다.

• 환경생물
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• 제18권1호
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• pp.53-61
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• 2000

서울시 소재 지하수 중 중금속으로 오염되어 음용수 이외의 생활 용수로 사용하고 있는 1개 정점과 음용수로 사용하고 있는 1개 정점, 대조군으로 강화도 천연 동굴의 1개 정점을 대상으로 실험을 실시하였다. 지하수 세균군집의 유전적 다양성의 변화를 보기 위해 지하수 세균 군집에서 16SrDNA를 증폭하는 primer로 PCR(polymerase chain reaction)을 실시한 후 ARDRA(amplified ribosomal DNA restriction analysis) 지문 분석으로 비교하였다. 16S rDNA를 증폭하여 제한효소 지문분석을 한 결과 in situ와 음용수에서 유전적 다양성이 상대적으로 크게 나타났다. 지하수 세균 군집의 ARDRA지문 분석은 상이한 환경과 서식지를 반영한 유전적 차이를 빠르게 비교 분석할 수 있었으며 지하수의 오염도에 따른 미생물의 다양성(천연 동굴>음용수>오염수)을 확인할 수 있었다.

• 한국식물병리학회지
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• 제12권1호
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• pp.91-98
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• 1996

벼도열병균 14개 균주와 벼 이외 화본과 식물 도열병균 12개 균주를 대상으로 rDNA의 ITS II 부위를 증폭하여 그들의 핵산 구조 차이를 분석함으로 도열병균 균주간 분류를 시도하였다. 5.8S rDNA의 3`-말단 부위와 28S rDNA의 5`-말단 부위의 sequence 중 5`-CCCGGGAATTCGCATCGATCGATCGAATGAAGA-ACGCAGC-3`와 5`-CCCGGGATCCTCCGCTTATT-GATATGC-3`를 이용하여 PCR 증폭을 하였을 때 벼도열병균 14개 균주는 동일한 길이의 단일 밴드를 형성하였으며 벼 이외 화본과 식물 도열병균에서는 레드톱 식물로부터 분리한 도열병균만이 나머지 균주보다 38bp가 더 큰 길이를 가진 밴드를 형성하였다. PCR로 증폭된 DNA를 HaeIII와 MspI 제한효소로 절단하였을 때 벼도열병균 레이스간에는 제한효소 절단에 의한 전기영동 밴드 형태 차이를 관찰할 수 없었으나, 벼 이외 화본과 식물 도열병균 12개 균주는 3군으로 구분할 수 있었다. 벼도열병균 90=054와 강아지풀에서 분리한 도열병균 G90-5, 기장에서 분리한 G88-4, 바랭이에서 분리한 G88-5 그리고 레드톱에서 분리한 RT 균주의 ITS II 부위의 DNA 염기서열 비교 분석에 의하면 G88-4와는 다른 HaeIII와 MspI 제한효소 위치를 가지고 있었기에 제한효소 절단에 의한 전기영동 형태가 상이하였다. 또한 RT균주는 HaeIII와 MspI위치가 존재하지 않았다.

• 대한수의학회지
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• 제34권4호
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• pp.759-768
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• 1994

E coli strains isolated from pigs were investigated with respect to antimicrobial resistances and prevalence of R-plasmids. Also determined were properties of R-plasmids by plasmid conjugation, curing and southern hybridization using gene probes. All of 400 E coli strains were resistant to CL and SU, and 0.3% to 96.8% of the strains were resistant to most antimicrobials such as TC, PG, AM, SM, CP, GM, EM, NM, etc, while all strains were sensitive to AK. All strains were also multiply resistant to three to twelve antimicrobials. The resistances to PG, SM, TC, AM, CP, SU and ST were transferable and supposed to be mediated by R-plasmids which were opportunistic for transposition into chromosome. Plasmids bigger in size than chromosomal DNA were considered as R-plasmids and most plasmids in small size (<4Kb) proved as cryptic plasmids or nonconjugative R-plasmids. In a strain(No 99), AM resistant property was determined from both chromosomal DNA and R-plasmid DNA which is bigger in size than chromosome.

• Animal cells and systems
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• 제5권3호
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• pp.231-236
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• 2001

SINE-R retroposons have been derived from human endogenous retrovirus HERV-K family and found to be hominoid specific. Both SINE-R retroposons and HERV-K family are potentially capable of affecting the expression of closely located genes. From cDNA library of human fetal brain, we identified seven SINE-R retroposons and compared them with sequences derived from GenBank database. The SINE-R retroposons from human feta1 brain showed 85∼97% sequence similarities with the human-specific retroposon SINE-R.C2. They also showed 88∼96% sequence similarities with the sequence of the schizo-cDNA clone that derived from postmortem frontal cortex tissue of a schizophrenic patient. Phylogenetic analysis using the neiqhbor-joining method revealed that the seven new SINE-R retroposons from cDNA library of the human feta1 brain have proliferated independently during human evolution. The data indicate that such SINE-R retroposons are expressed in human fetal brain and deserve further investigation as potential leads to understanding of neuropsychiatric diseases.

• Journal of Yeungnam Medical Science
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• 제19권1호
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• pp.1-10
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• 2002

With the establishment of rapid sequence analysis of 16S rRNA and the recognition of its potential to determine the phylogenetic position of any prokaryotic organism, the role of 16S rRNA similarities in the present species definition in bacteriology need to be clarified. Comparative studies clearly reveal the limitations of the sequence analysis of this conserved gene and gene product in the determination of relationship at the pathogenic strain level for which DNA-DNA reassociation experiments still constitute the superior method. Since today the primary structure of 16S rRNA is easier to determine than hybridization between DNA strands, the strength of the sequence analysis is to recognize the level at which DNA pairing studies need to be performed, which certainly applies to similarities of 97% and higher.