• Horticultural Science & Technology
• /
• v.17 no.1
• /
• pp.7-10
• /
• 1999

This study was carried out with the purpose of looking into the transcriptionally regulated genes related to the anther development, characterizing them, and applying their promoters to induce male-sterile plants and restore their fertility. Fifteen anther-specific clones were isolated from the anther cDNA library of Chinese cabbage through the differential screening and sequenced partially at both ends. These partial sequence data showed that cDNA clones BAN52, 84, 101, and 229 are very similar to polygalacturonase, ascorbate oxidase, $H^+-translocating$ ATPase, and pectin esterase genes respectively. However, the other clones have not been matched to any of gene sequences in data bank. In northern dot blot analysis, the transcripts of cDNA clone BAN5, 10, 33, 52, 57, 102, 103, 215, 229 appeared in the flower bud of 2.1 mm in length and their amounts were gradually increased along with the anther development. Transcription of cDNA clone BAN32, 54, 62, 84, 101 began in flower bud of 3.9 mm, which is the late stage in anther development. However, the transcription of BAN87 was very small, but its transcript was detected in all anther developmental stages.

• Research in Plant Disease
• /
• v.18 no.3
• /
• pp.236-239
• /
• 2012

In July, 2009, proso millet (Panicum miliaceum), which showing the bacterial brown stripes on leaf sheaths, was collected in Miryang in Korea. Symptoms were systemic brown necrotic stripe lesions on the leaf sheaths and stems, and these symptoms were found in the entire field. The causal agent isolated from symptomatic plants was identified as an Acidovorax avenae subsp. avenae, based on its biochemical and physiological characteristics and also confirmed by the Biolog data and 16S rRNA gene sequence analysis. Also it caused hypersensitive response (HR) when it was inoculated onto the tobacco and tomato. It caused similar symptoms when inoculated onto proso millet. This is the first report of A. avenae subsp. avenae, the causal agent of bacterial brown stripe of the proso millet in Korea.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.10
• /
• pp.1085-1091
• /
• 2009

A phytase with high activity at low temperatures has great potential for feed applications, especially in aquaculture. Therefore, this study used a degenerate PCR and TAIL PCR to clone a phytase gene from Erwinia carotovora var. carotovota, the cause of soft rot of vegetables in the ground or during cold storage. The full-length 2.5-kb fragment included an open reading frame of 1,302 bp and encoded a putative phytase of 45.3 kDa with a 50% amino acid identity to the Klebsiella pneumoniae phytase. The phytase contained the active site RHGXRXP and HD sequence motifs that are typical of histidine acid phosphatases. The enzyme was expressed in Escherichia coli, purified, and displayed the following characteristics: a high catalytic activity at low temperatures (retaining over 24% activity at $5^{\circ}C$) and remarkably thermal lability (losing >96% activity after incubation at $60^{\circ}C$ for 2 min). The optimal phytase activity occurred at pH 5.5 and ${\sim}49^{\circ}C$, and the enzyme activity rapidly decreased above $40^{\circ}C$. When compared with mesophilic counterparts, the phytase not only exhibited a high activity at a low temperature, but also had a low $K_m$ and high $k_{cat}$. These temperature characteristics and kinetic parameters are consistent with low-temperature-active enzymes. To our knowledge, this would appear to be the first report of a low-temperature-active phytase and its heterogeneous expression.

• The Korean Journal of Pesticide Science
• /
• v.20 no.4
• /
• pp.349-354
• /
• 2016

Triazole fungicides occupy an important portion in the global fungicide market and are relatively persistent in soil compared to the other fungicides, suggesting possible adverse effects of the fungicides on human health and environment. In this study, we tried to isolate microorganisms from orchard soils, which can decompose the triazole fungicides, tebuconazole, fluquinconazole, and difenoconazole. Only difenoconazole was completely degraded in the enrichment culture, from which several difenoconazole-degrading bacteria were isolated. They showed the same rep-PCR pattern thus only one strain, C8-2, was further studied. The strain was identified as Sphingomonas sp. C8-2 based on its 16S rRNA gene sequence and decomposed 100 mg/L of difenoconazole in a minimum medium to an unknown metabolite with a molecular weight of 296 within 24 hours. The inhibition effect of the metabolite against representative soil microorganisms significantly decreased compared to that of difenoconazole thus the bacterial strain is expected to be used for the detoxification of difenoconazole in soil and crop.

• Microbiology and Biotechnology Letters
• /
• v.40 no.2
• /
• pp.98-103
• /
• 2012

For screening of useful enzymes producing microorganisms from Meju, we isolated high lipase producing strains and their lipolytic enzyme activities were then tested. The lipolytic enzyme activities of isolated microorganisms were therefore tested on the Y124 strain. The gene sequence analysis of ITS from Y124 strain revealed Yarrowia lipolytica. Lipase production by the Y124 strain was studied in media containing various carbon sources. The Y124 strain drastically increased lipolytic enzyme activity in YPO media containing olive oil, as well as in YPDO media containing both olive oil and glucose. Maximal lipase production was achieved in YPD (yeast extract-peptone-D-glucose) media containing 0.7% olive oil when cultured at $30^{\circ}C$ for 8 hrs. The lipase produced from the Y124 strain showed the highest activity in p-NPO (p-nitrophenyl octanoate ($C_8$)), amongst the various p-nitrophenyl esters.

• The Korean Journal of Mycology
• /
• v.25 no.4 s.83
• /
• pp.330-339
• /
• 1997

Botrytis cinerea T91-1 has shown to produce at least four different polygalacturonases in a liquid medium containing citrus pectin as a carbon source. One of the enzymes, its molecular weight was estimated as 37 kDa by denatured polyacrylamide gel electrophoresis, was purified by a series of procedures including acetone precipitation, ion exchange, heparin affinity, and reverse phase column chromatographies. By viscometric analysis, the enzyme was revealed as an endo-polygalacturonase. The enzyme activity was inhibited by divalent cations such as $Ca^{2+}$, $Co^{2+}$, and $Cu^{2+}$. Km and Vmax for polygalacturonic acid hydrolysis were 0.33 mg/ml and 28.6 nM/min, respectively. The optimum temperature for enzymatic activity was $55^{\circ}C$ and the enzyme showed optimal pH values between 4.0 and 4.5. The enzyme was stable up to 12 hours in the range of pH 4 to 7 and at the temperature below $30^{\circ}C$. Amino acid sequence from N-terminal up to 6 amino acids determined by Edman degradation showed little homology with polygalacturonases from fungi and plants.

• BMB Reports
• /
• v.40 no.6
• /
• pp.911-920
• /
• 2007

Tuberculosis, caused by Mycobacterium tuberculosis, continues to be one of the leading infectious diseases to humans. It is urgent to discover novel drug targets for the development of antitubercular agents. The 2-C-methyl-Derythritol-4-phosphate (MEP) pathway for isoprenoid biosynthesis has been considered as an attractive target for the discovery of novel antibiotics for its essentiality in bacteria and absence in mammals. MEP cytidyltransferase (IspD), the third-step enzyme of the pathway, catalyzes MEP and CTP to form 4-diphosphocytidyl-2-C-methylerythritol (CDP-ME) and PPi. In the work, ispD gene from M. tuberculosis H37Rv (MtIspD) was cloned and expressed. With N-terminal fusion of a histidine-tagged sequence, MtIspD could be purified to homogeneity by one-step nickel affinity chromatography. MtIspD exists as a homodimer with an apparent molecular mass of 52 kDa. Enzyme property analysis revealed that MtIspD has high specificity for pyrimidine bases and narrow divalent cation requirements, with maximal activity found in the presence of CTP and $Mg^{2+}$. The turnover number of MtIspD is $3.4 s^{-1}$. The Km for MEP and CTP are 43 and $92{\mu}M$, respectively. Furthermore, MtIspD shows thermal instable above $50^{\circ}C$. Circular dichroism spectra revealed that the alteration of tertiary conformation is closely related with sharp loss of enzyme activity at higher temperature. This study is expected to help better understand the features of IspD and provide useful information for the development of novel antibiotics to treat M. tuberculosis.

• Journal of Life Science
• /
• v.25 no.11
• /
• pp.1273-1279
• /
• 2015

Agarase from a novel agar-degrading bacterium isolated from seawater in Namhae at Gyeongsangnamdo province of Korea was characterized. The SH-1 strain was selected from thousands of colonies on Marine agar 2216 media. Almost full 16S rRNA gene sequence of the agarolytic SH-1 strain showed 99% similarity with that of bacteria of Simiduia genus and named as Simiduia sp. SH-1. Agarase production was growth related, and activity was declined from stationary phase. Secreted agarase was prepared from culture media and characterized. It showed maximum activity of 698.6 units/L at pH 7.0 and 30℃ in 20 mM Tris-HCl buffer. Agarase activity decreased as the temperature increased from an optimum of 30℃, with 90% and 75% activity at 40℃ and 50℃, respectively. Agarase was not heat resistant. Slightly lower agarase activity was observed at pH 6.0 than at pH 7.0, without statistical difference, and 80% and 75% activity were observed at pH 5.0 and 8.0, respectively. Neoagarotetraose and neoagarobiose were the main final products of agarose, indicating that it is β-agarase. Simiduia sp. SH-1 and its β-agarase would be useful for the industrial production of neoagarotetraose and neoagarobiose, which have a whitening effect on skin, delaying starch degradation, and inhibiting bacterial growth.

• Korean Journal of Plant Taxonomy
• /
• v.37 no.1
• /
• pp.1-15
• /
• 2007

Phylogenetic studies were conducted for 42 populations of Korean viola based on matK gene and atpB-rbcL intergenic spacer region of chloroplast DNA. In the matK tree, section Chamaemelanium and Dischidium were formed as a distinct group. Five subsections of section Nomimium were paraphyletic. In atpB-rbcL intergenic spacer region analysis, two species of sect. Chamaemelanium were monophyletic, and section Dischidium was placed sister to subsection patellares clade except for V. keiskei. Five subsections of section Nomimium were also paraphyletic as matK tree. the separate data analyses were incongruent in the relationships among 42 populations, especially for the position of section Dischidium and V. keiskei. The combined analyses of two chloroplast regions showed three major clades; section Chamaemelanium and Dischidium (x=6) formed a sister to subsections Hypocarpae and Trigonocarpae (x=10) clade; subsections Bilobatae and vaginatae (x=10 or 12) formed a clade with V. keiskei; and 19 populations of subsection patellares (x=12) except for V. keiskei were recognized as an independent clade within section Nomimium. Although combined data suggest three major clades of Korean viola, the origins of each clade from outgroup were discordance with previous ITS and trnL-F data.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.2
• /
• pp.125-131
• /
• 2015

Phenyllactic acid (PLA) which is known as antimicrobial compound can be synthesized through the reduction of phenylpyruvic acid (PPA) by lactate dehydrogenase (LDH) of lactic acid bacteria (LAB). LAB producing PLA was isolated from Korea Kimchi and identified to Lactobacillus plantarum SJ21 by 16 rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. plantarum SJ21 was assessed for both the capability to produce the antimicrobial compound PLA and the antifungal activity against four fungal pathogens (Rhizoctonia solani, Aspergillus oryzae, Botrytis cinerea, and Collectotricum aculatum). PLA concentration was investigated to be 3.23mM in CFS when L. plantarum SJ21 was grown in MRS broth containing 5mM PPA for 16 h. PLA production also could be promoted by the supplement of PPA and phenylalanine in MRS broth, but inhibited by the supplement of 4-hydroxyphenylpyruvic acid and tyrosine as precursors. Antifungal activity demonstrated that all fungal pathogens were sensitive to 5% CFS (v/v) of L. plantarum SJ21 with average growth inhibitions ranging from 27.32% to 69.05% (p<0.005), in which R. solani was the most sensitive to 69.05% and followed by B. cinerea, C. aculatum, and A. oryzae. The minimum inhibitory concentration (MIC) for commercial PLA was also investigated to show the same trend in the range from $0.35mg\;mL^{-1}$ (2.11 mM) to $0.7mg\;mL^{-1}$ (4.21 mM) at pH 4.0. The inhibition ability of CFS against the pathogens was not affected by heating or protease treatment. However, pH modification in CFS to 6.5 caused an extreme reduction in their antifungal activity. These results may indicate that antifungal activities in CFS were caused by acidic compounds like PLA or organic acids rather than proteins or peptides molecules.