• The Journal of Korean Society of Virology
• /
• v.28 no.4
• /
• pp.327-335
• /
• 1998

Hantaan (HTN) and Seoul (SEO) viruses, murid rodent-borne hantaviruses, are known to causes hemorrhagic fever with renal syndrome (HFRS) in Korea. To determine the genomic diversity and molecular phylogeny of HTN and SEO viruses found in Korea, we amplified for part of M and S genomic segments of hantaviruses from sera of HFRS patients and lung tissues of hantavirus seropositive striped-field mice. Both M and S segment of 16 HTN and 2 SEO viruses were amplified by nested reverse transcription-polymerase chain reaction. Based on 324 nucleotides in the M genomic segment, the HTN and SEO strains showed $93.8{\sim}100%$ and $99.1{\sim}99.4%$ homologies, respectively. Similarly, based on 230 nucleotides in the S genomic segment, HTN and SEO strains showed $90.9{\sim}100%$ and 100% homologies, respectively. Phylogenetic analysis of M and S segments indicated that HTN strains could be divided into at least two main groups in M and S trees and the sequence differences detected among the Sand M genomic segments of HTN viruses are consistent with reassortment having taken place between HTN virus strains.

• Microbiology and Biotechnology Letters
• /
• v.34 no.1
• /
• pp.1-6
• /
• 2006

Harmful algal blooms (HABs or red tides), caused by uncontrolled proliferation of marine phytoplankton, impose a severe environmental problem and occasionally threaten even public health. We sequenced the genome of an EPS-producing marine bacterium Hahella chejuensis that produces a red pigment with the lytic activity against red-tide dinoflagellates at parts per billion level. H. chejuensis is the first sequenced species among algicidal bacteria as well as in the order Oceanospirillales. Sequence analysis indicated a distant relationship to the Pseudomonas group. Its 7.2-megabase genome encodes basic metabolic functions and a large number of proteins involved in regulation or transport. One of the prominent features of the H. chejuensis genome is a multitude of genes of functional equivalence or of possible foreign origin. A significant proportion (${\sim}23%$) of the genome appears to be of foreign origin, i.e. genomic islands, which encode genes for biosynthesis of exopolysaccharides, toxins, polyketides or non-ribosomal peptides, iron utilization, motility, type III protein secretion and pigment production. Molecular structure of the algicidal pigment was determined to be prodigiosin by LC-ESI-MS/MS and NMR analyses. The genomics-based research on H. chejuensis opens a new possibility for controlling algal blooms by exploiting biotic interactions in the natural environment and provides a model in marine bioprospecting through genome research.

• Korean Journal of Medicinal Crop Science
• /
• v.24 no.1
• /
• pp.55-61
• /
• 2016

Background : Plant breeding requires the collection of genetically diverse genetic resources. Studies on the characteristics of Platycodon grandiflorum resources have not been carried out so far. The present study was carried out to discriminate P. grandiflorum based on morphological characteristics and genetic diversity using simple sequence repeat (SSR) markers. Methods and Results :We collected 11 P. grandiflorum cultivars: Maries II, Hakone double white, Hakone double blue, Fuji white, Fuji pink, Fuji blue, Astra white, Astra pink, Astra blue, Astra semi-double blue and Jangbaek. Analyses of the morphological characteristics of the collection were conducted for aerial parts (flower, stem and leaf) and underground parts (root). Next, the genetic diversity of all P. grandiflorum resources was analyzed using SSR markers employing the DNA fragment analysis method. We determined that the 11 P. grandiflorum cultivars analyzed could be classified by plant length, leaf number and root characteristic. Based on the genetic diversity analysis, these cultivars were classified into four distinct groups. Conclusions : These findings could be used for further research on cultivar development using molecular breeding techniques and for conservation of the genetic diversity of P. grandiflorum. Moreover, the markers could be used for genetic mapping of the plant and marker-assisted selection for crop breeding.

• The Plant Pathology Journal
• /
• v.19 no.2
• /
• pp.123-127
• /
• 2003

A severe disease of muskmelon (Cucumis melo cv. Alsnight) grown on rockwool in a plastic house was characterized by leaf and stem necrosis followed by death of the plants. In 2001, an isolate of Melon necrotic spot virus-MN (MNSV-MN) of the genus Camovirus was identified as the causal agent of the disease on the basis of biological reactions and nucleotide sequence analyses of coat protein (CP) gene. MNSV-MN induced necrotic local lesions on mechanically inoculated leaves and systemic necrotic spots on the upper leaves of melon cvs. Alsnight, Rui III, Party, Imperial, and Seolhang. However, the inoculated leaves of watermelon and cucumber showed only necrotic lesions. DsRNAs extracted from the melon infected with MNSV-MN were separated into three components. Molecular sizes of the dsRNAs were estimated at approximately 4.5, 1.8, and 1.6 kbp. The amplified cDNA products of CP gene for MNSV-MN by RT-PCR showed approximately 1.2 kbp. The amplified DNA was digested to three fragments by MspI treatment. The cDNA of the genomic RNA of MNSV-MN was cloned and the region deduced to encode the CP was sequenced. The CP coding region, located near 3' end of the genome, consisted of 1,170 nucleotides and had the potential to encode a 390 amino acid protein. The nucleotide and amino acid sequences of MNSV-MN CP gene were 84.0-94.6% and 90.8-94.9% identical with other MNSV isolates found in the GeneBank database, respectively. This is the first report on the occurrence of MNSV in Korea.

• Journal of Life Science
• /
• v.14 no.1
• /
• pp.32-37
• /
• 2004

A portion of ribosomal internal transcribed spacer (ITS) 2 was sequenced from the samples of Pseudo nitzschia (P. deticatissima, P. multiseries, P. pungens and P. subfraudulenta) to investigate the genetic characteristics by measuring tile magnitude of genetic diversity and the degree of similarity coefficient using random amplified polymorphic DNAs (RAPD)-PCR patterns. The phylogenetic trees inferred from the genetic distance analyses showed the placement of P. delicatissima formed a quite long distance from p. P. multiseries, P. pungens, and even P. subfraudulenta. The phylogenetic tree from RAPD patterns showed that P. multiseries and P. pungens had dissimilarity coefficient of 0.31, while P. delicatissima and three species of Pseudo-nitzschia had that of 0.81. It is likely thought that the genetic position of P. delicatissima formed far from P. multiseries, P. punges, and P. subfraudulenta. These results imply that ITS2 region is expected to support a useful molecular characters for recognizing at the species level and for even discriminating P. multiseries from P. pungens. RAPD method also will be used to differentiate the species of Pseudo-nitzschia in a short time.

• International Journal of Oral Biology
• /
• v.42 no.2
• /
• pp.63-70
• /
• 2017

Selecting an appropriate antigen with optimal immunogenicity and physicochemical properties is a pivotal factor to develop a protein based subunit vaccine. Despite rapid progress in modern molecular cloning and recombinant protein technology, there remains a huge challenge for purifying and using protein antigens rich in hydrophobic domains, such as membrane associated proteins. To overcome current limitations using hydrophobic proteins as vaccine antigens, we adopted in silico analyses which included bioinformatic prediction and sequence-based protein 3D structure modeling, to develop a novel periodontitis subunit vaccine against the outer membrane protein FomA of Fusobacterium nucleatum. To generate an optimal antigen candidate, we predicted hydrophilicity and B cell epitope parameter by querying to web-based databases, and designed a truncated FomA (tFomA) candidate with better solubility and preserved B cell epitopes. The truncated recombinant protein was engineered to expose epitopes on the surface through simulating amino acid sequence-based 3D folding in aqueous environment. The recombinant tFomA was further expressed and purified, and its immunological properties were evaluated. In the mice intranasal vaccination study, tFomA significantly induced antigen-specific IgG and sIgA responses in both systemic and oral-mucosal compartments, respectively. Our results testify that intelligent in silico designing of antigens provide amenable vaccine epitopes from hard-to-manufacture hydrophobic domain rich microbial antigens.

• Molecules and Cells
• /
• v.38 no.12
• /
• pp.1086-1095
• /
• 2015

The psychrophilic organism Colwellia psychrerythraea strain 34H produces extracellular polysaccharide substances to tolerate cold environments. Sedoheptulose 7-phosphate isomerase (GmhA) is essential for producing $\small{D}$-glycero-$\small{D}$-mannoheptose 7-phosphate, a key mediator in the lipopolysaccharide biosynthetic pathway. We determined the crystal structure of GmhA from C. psychrerythraea strain 34H (CpsGmhA, UniProtKB code: Q47VU0) at a resolution of $2.8{\AA}$. The tetrameric structure is similar to that of homologous GmhA structures. Interestingly, one of the catalytic residues, glutamate, which has been reported to be critical for the activity of other homologous GmhA enzymes, is replaced by a glutamine residue in the CpsGmhA protein. We also found differences in the conformations of several other catalytic residues. Extensive structural and sequence analyses reveal that CpsGmhA shows high similarity to Escherichia coli DnaA initiatorassociating protein A (DiaA). Therefore, the CpsGmhA structure reported here may provide insight into the structural and functional correlations between GmhA and DiaA among specific microorganisms.

• Korean Journal of Plant Taxonomy
• /
• v.49 no.2
• /
• pp.127-139
• /
• 2019

The purported four hybrid origins of Asplenium in Korea were tested based on morphological, cytological and DNA sequence data. Asplenium castaneo-viride, A. ${\times}$ uiryeongse, A. ${\times}$ montanus, and A. ${\times}$ kitazawae share several morphological characteristics with the Asian walking fern A. ruprechtii and related taxa as parents and show a sympatric distribution with the putative parents, raising the possibility of hybrid origins: A. castaneo-viride (A. ruprechtii and A. incisum), A. ${\times}$ uiryeongse (A. ruprechtii and A. pekinense), A. ${\times}$ montanus (A. ruprechtii, A. trichomanes, and A. incisum), and A. ${\times}$ kitazawae (A. ruprechtii and A. sarelii). We investigated flow cytometry and chloroplast DNA sequence data (rbcL, rps4-trnS, and rps4-trnS intergenic spacer) to clarify the hybridization and origin of each hybrid. In the flow cytometry analyses, A. ruprechtii shows diploid (2x) only, whereas A. castaneo-viride (3x, 4x), A. ${\times}$ uiryeongse (3x), A. ${\times}$ montanus (3x, 4x), and A. ${\times}$ kitazawae (2x, 4x) exhibit polyploidy, suggesting hybrid events along speciation. The rbcL and rps4-trnS and rps4-trnS intergenic spacer data suggest that A. ruprechtii is one the maternal ancestors of all four hybrids. In addition, the rps4-trnS and rps4-trnS intergenic spacer data indicate that A. incisum is also the maternal ancestor of A. ${\times}$ kitazawae and A. ${\times}$ montanus, proposing multiple hybridization events for these two hybrids. In A. ${\times}$ montanus, morphological features such as the leaf forms and sympatric distributions of the species also support the multimaternal hypothesis, but the morphological features of A. ${\times}$ kitazawae must be examined with consideration of hybrid events. To clarify the complex hybrid evolutionary lineages of the four Asplenium hybrids, further research with taxon sampling and molecular markers should be conducted.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.2
• /
• pp.272-279
• /
• 2021

Two genes encoding probable α-ʟ-arabinofuranosidase (E.C. 3.2.1.55) isozymes (ABFs) with 92.3% amino acid sequence identity, ABF51A and ABF51B, were found from chromosomes 3 and 5 of Saccharomycopsis fibuligera KJJ81, an amylolytic yeast isolated from Korean wheat-based nuruk, respectively. Each open reading frame consists of 1,551 nucleotides and encodes a protein of 517 amino acids with the molecular mass of approximately 59 kDa. These isozymes share approximately 49% amino acid sequence identity with eukaryotic ABFs from filamentous fungi. The corresponding genes were cloned, functionally expressed, and purified from Escherichia coli. SfABF51A and SfABF51B showed the highest activities on p-nitrophenyl arabinofuranoside at 40~45℃ and pH 7.0 in sodium phosphate buffer and at 50℃ and pH 6.0 in sodium acetate buffer, respectively. These exoacting enzymes belonging to the glycoside hydrolase (GH) family 51 could hydrolyze arabinoxylo-oligosaccharides (AXOS) and arabino-oligosaccharides (AOS) to produce only ʟ-arabinose, whereas they could hardly degrade any polymeric substrates including arabinans and arabinoxylans. The detailed product analyses revealed that both SfABF51 isozymes can catalyze the versatile hydrolysis of α-(1,2)- and α-(1,3)-ʟ-arabinofuranosidic linkages of AXOS, and α-(1,2)-, α-(1,3)-, and α-(1,5)-linkages of linear and branched AOS. On the contrary, they have much lower activity against the α-(1,2)- and α-(1,3)-double-substituted substrates than the single-substituted ones. These hydrolases could potentially play important roles in the degradation and utilization of hemicellulosic biomass by S. fibuligera.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.33-33
• /
• 2022

Rice (Oryza sativa L.) is a widely studied domesticated model plant. Seed awning is an unfavorable trait during rice harvesting and processing. Hence, awn was one of the target characters selected during domestication. However, the genetic mechanisms underlying awn development in rice are not well understood. In this study, we analyzed the genes for awn development using a mapping population derived from a cross between the Korean indica cultivar 'Milyang23' and NIL4/9 (derived from a cross between 'Hwaseong' and O. minuta). Two quantitative trait loci (QTLs), qAwn4 and qAwn9 were mapped on chromosome 4 and 9, respectively, increased awn length in an additive manner. Through comparative sequencing analyses parental lines, LABA1 was determined as the causal gene underlying qAwn4. qAwn9 was mapped to a 199-kb physical region between markers RM24663 and RM24679. Within this interval, 27 annotated genes were identified, and five genes, including a basic leucine zipper transcription factor 76 (OsbZIP76), were considered candidate genes for qAwn9 based on their functional annotations and sequence variations. Haplotype analysis using the candidate genes revealed tropical japonica specific sequence variants in the qAwn9 region, which partly explains the non-detection of qAwn9 in previous studies that used progenies from interspecific crosses. This provides further evidence that OsbZIP76 is possibly a causal gene for qAwn9. The O. minuta qAwn9 allele was identified as a major QTL associated with awn development in rice, providing an important molecular target for basic genetic research and domestication studies. Our results lay the foundation for further cloning of the awn gene underlying qAwn9.