• Korean Journal of Plant Taxonomy
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• v.53 no.2
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• pp.126-147
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• 2023

The taxonomic identity of Elaeagnus ×maritima and E. ×submacrophylla (Elaeagnaceae) in Korea is unclear, yet they are presumed to be hybrid taxa based on their morphology. To determine their hybrid origins, a morphological analysis (field surveys and specimen examinations) and a molecular analysis involving two nuclear ribosomal DNA (nrDNA) regions (internal transcribed spacer and 5S non-transcribed spacer) and one chloroplast DNA (cpDNA) region (matK) were conducted. The morphological analysis revealed that E. ×maritima showed certain morphological similarities to E. glabra, whereas E. ×submacrophylla showed certain morphological similarities to E. pungens. However, the molecular analysis indicated that E. ×maritima exhibited additive species-specific sites of E. glabra and E. macrophylla in the nrDNA regions. Notably, E. ×submacrophylla showed various aspects, with some individuals exhibiting additive species-specific sites of E. pungens and E. macrophylla in the nrDNA and E. macrophylla sequences in the cpDNA regions, some individuals exhibiting E. macrophylla sequences in the nrDNA and E. pungens sequences in the cpDNA regions, and some individuals displaying E. macrophylla sequences in both the nrDNA and cpDNA regions, despite an intermediate morphology between E. pungens and E. macrophylla. These results indicate that these two species are of hybrid origin and frequently cross between parental and hybrid individuals.

• The Korean Journal of Zoology
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• v.37 no.2
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• pp.240-248
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• 1994

골격근 세포는 미분화 단핵 근원세포로부터 신장과 융합을 거쳐 다핵 횡문근섬유로 분화되어 가며 동시에 근특이 유전자의 발현이 선택적으로 일어난다. 본 연구에서는 계배 배양 근원세포의 분화동안 유전자 발현 조절 양상에 대한 연구를 위해, 계배 근원세포를 72시간 배양한 근섬유로부터 CDNA 라이브러리를 제작하였다. 이 cDNA 라이브러리를 미분화 단핵 근원세포(배양 36시간)와 분화된 다핵 근섬유(배양 72시간)의 poly(A)+ RNA 주형에서 합성된 [32P〕cDNA를 Probe로 사용한 differential plaque hybridization 방법으로 스크리닝하였다 분화된 다핵 근섬유 CDNA probe에 강한게 흔성화되는 CDNA clone을 선별하여 클로닝하였다. 선별한 CDNA clone 들 중 하나는 약 1.3 Kb 크기의 삽입절편을 갖고 있는 것으로 나타났고, 이 CDNA를 probe로 사용하여 northern blotting 한 결과, 이 CDNA엑 대한 유전자는 미분화 단핵 근원세포에서 분화된 다핵 근섬유로 분화가 진행됨에 따라 유전자 산물인 RNA 양이 증가되는 것으로 나타났다 또한 이 1.3 Kb CDNA에 대한 RNA의 크기는 약 2 7 Kb로 확인되었다.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.173-177
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• 1997

Bacillus licheniformis 9945a releases a natural ${\gamma}-poly(glutamic\;acid)({\gamma}-PGA)$ into fermentation broth and shows a mucoid phenotype on the solid agar medium. Transformation of mucoid cells of Bacillus species has not been simple and straightforward. The transpositional activity of Tn10 in B. licheniformis also has not been own either. Thus, a spontaneous non-mucoid derivative of the B. licheniformis was obtained first. Shuttle vector pHV1248 containing mini-Tn10 was introduced into the non-mucoid derivative by the method of protoplast transformation. The resulting transformant was reverted to the wild mucoid phenotype, and then mutated randomly with the mini-transposon by heat induction. Auxotrophs requiring arginine, lysine, or tryptophan were isolated by replica plating method. Southern blotting and DNA-DNA hybridzation analysis showed that these auxotrophs were generated by mini-Tn10 insertion into the chromosomal DNA. This method of transformation and mutation using pHV1248 would be useful for the generation of diverse mutants of B. licheniformis 9945a.(Received January 24,1997; accepted March 10, 1997)

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.700-705
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• 2014

An anagram is a form of word play to find a new word from a set of given alphabet letters. Good human anagram solvers use the strategy of bigrams. They explore a constraint satisfaction network in parallel and answers consequently pop out quickly. In this paper, we propose a molecular computational algorithm using the same process as this. We encoded letters into DNA sequences and made bigrams and then words by connecting the letter sequences. From letters and bigrams, we performed DNA hybridization, ligation, gel electrophoresis and finally, extraction and separation to extract bigrams. From the matched bigrams and words, we performed the four molecular operations again to distinguish between right and wrong results. Experimental results show that our molecular computer can identify cor rect answers and incorrect answers. Our work shows a new possibility for modeling the cognitive and parallel thinking process of a human.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.27-36
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• 1993

Rhizobium fredii USDA191 은 대기 중의 질소를 환원하여 식물체의 생육에 필요한 질소원을 공급해주는 세균으로 다량의 체외 다당류를 합성한다. 전위요소 Tn5의 삽입에 의한 돌연변이 유도로 다당류결핍 변이주 R. fredii YKL293 가 분리되었으며 이 변이주로부터 Tn5 에 인접한 DNA 단편이 pUC19 에 클로닝되었고(plyk5293),이 DNA 단편을 탐침으로 하여 .lambda.NM1149 에 구성되 USDA191 genomic library 로부터 야생형체외다당류 합성관련 유전자(exo) 를 함유한 클론 .lambda. NM1149 22E 를 plaque 혼성화에 의하여 분리하였다. 클론 NM1149.22E 에 들어있는 exo 유전자를 pBR322 에 옮겨서 pJW33을 만들고, 재조합체 pJW33 을 Escherichia coli POII734 에 도입시켜 lacZ 구조유전자를 함유한 MudI 1734 가 exo 유전자의 프러모토와 융합되어 lacZ 구조유전자의 전사가 이루어지도록 하였다. 위와 같이 만들어진 재조합체 플라스미드 pUM21을 함유한 E. coli JM83 은 .betha.-galactosidase 를 합성하였으며, 야생형 tacZ 유전자를 갖고 있는 E. coli LE392 에 비해서 14-25배 정도 낮은 역가를 보였다.

• Korean Journal of Plant Taxonomy
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• v.52 no.2
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• pp.85-96
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• 2022

The plant "Hong-do-go-deul-ppae-gi" has been considered as Crepidiastrum × muratagenii, a hybrid between C. denticulatum and C. lanceolatum, based on its morphological traits and geographical distribution. To reveal the hybrid origin of Hong-do-go-deul-ppae-gi, we examined additional morphological traits of this plant and its putative parents (C. denticulatum, C. lanceolatum, C. platyphyllum) and analyzed one nuclear ribosomal internal transcribed spacer (ITS) region and four chloroplast regions (trnT-L, trnL-F, rpl16 intron, and rps16 intron). As a result of examining the morphological traits, putative hybrid individuals were classified into three types based on the habit, cauline leaf, outer phyllary, and achene beak traits. A molecular analysis found that the ITS sequences of Type 1 and Type 2 individuals showed additive species-specific sites of C. denticulatum and C. lanceolatum. Plastid sequences of Type 1 and Type 2 individuals showed C. denticulatum and C. lanceolatum sequences, respectively. However, Type 3 individuals had ITS and plastid sequences corresponding to C. denticulatum. Accordingly, Type 1 and Type 2 individuals not only share morphological traits with C. denticulatum and C. lanceolatum but also show additive species-specific sites for C. denticulatum and C. lanceolatum, and not C. platyphyllum, supporting its origin as a hybrid between C. denticulatum and C. lanceolatum. Type 3 had morphological traits similar to other hybrid types but was distinguished with respect to outer phyllaries and demonstrated some resemblance to C. denticulatum. In a molecular analysis, Type 3 was found to be identical with regard to the sequence of C. denticulatum and was judged to be an ecological variation of C. denticulatum.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.339-344
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• 2005

Rice blast, which is caused by the fungus Magnaporthe grisea, is one of the most destructive diseases of rice. To identify genes involving in the signal transduction pathways that mediate rice blast resistance, we screened over 2,000 mutant lines of a highly resistant variety RIL260 that were generated by using a DEB (1, 3-Butadiene diepoxide) treatment method. In the mutant population, the frequency of albino plants was 6.7%, indicating that this population has a high frequency of mutations in the genome. The primary screening identified 29 mutant plants that exhibit a complete or partial loss of the resistance to rice blast. Among them, M5465, the most susceptible line, was subsequently examined by DNA gel-blot experiments using DNA molecular markers of Pi5(t) that has been previously identified as a durable resistance locus in RIL260. The result revealed that a large deletion and rearrangement of genomic DNA occurred in the Pi5(t) locus. The results suggest that DEB can be used as an efficient mutagen to induce large scale mutations in the rice genome. The isolated mutants should be useful for elucidating the Pi5(t)-mediated signaling pathways of rice blast resistance.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.118-124
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• 1997

In the previous study(6), we constructed the CheY-OmpR hybrid, Chp, which affects the expressions of ompF and om pC genes. Here we further characterize these effects and present the regulatory mechanism based on in vivo and in vitro data. Although Chp retained the sequence-specific DNA-binding ability, it was not possible to enhance transcriptional activity, suggesting that it may act as a competitive inhibitor to OmpR. The DNA-binding affinity of Chp was not modulated by phosphorylation of its Che Y portion. Chp was able to increase ompR transcription. FurthemlOre, it was found that the wild-type OmpR also exerts the same effect, which is also eOlltrolled by changes in medium osmolarity and in EnvZ activity.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.121-126
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• 1999

Calli were induced from the petiole explants of Pimpinella brachycarpa on MS medium supplemented with 0.5 mg/L 2,4-D and 0.1 mg/L BA after four weeks of culture. Compact clusters of small and dense cells among these calli were selected and suspension-cultured as the source of embryogenic calli. When transferred to MS medium with 0.1 mg/L NAA, the suspension-cultured cells grew to embryogenic callus. Somatic embryos derived from these embryogenic calli developed into plantlets. The cDNA library was constructed in the embryogenic callus and in order to screen the cDNA library, these cDNAs were plated at a density 1.5 $\times$ 10^5 plaques per 15 cm petridish. Among 19 clones showing preferential hybridization with petiole HD-Zip gene, five clones were obtained after second screening. Four clones among them, were highly homologous to P. brachycarpa shoot-tip Phz4 gene, but one clone, Phc5 was about 1.5 kb which has an extra 163 bp to 5' upstream of Phz4. The Phc5 was 1,531 bp containing poly A tails of 18 bases. ATG start codon for Phc5, was located at position 284 with an open reading frame of 906 by which encodes a polypeptide of 302 amino acids. The Phc5 protein revealed that the polypeptides between 135 and 195 contain a homeodomain as the `leucine zipper' motif.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.347-351
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• 2007

Potato scab is prevalent in all potato-growing areas of Jeju Island and causes economically significant losses. Streptomyces species are known as pathogens of potato scab. In this study, we analyzed the 16S rRNA sequences of Streptomyces spp, which are isolated from potato scab lesions in Jeju Island, and constructed 16S rRNA phylogenetic tree. All isolates were clearly differentiated into the genus Streptomyces, and the tree also showed that new scab-causing Streptomyces spp or not yet named species of Streptomyces are existed in Jeju Island, Korea.