• Journal of Korean Society of Forest Science
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• 제96권1호
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• pp.58-64
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• 2007

Overwintering adults of sycamore lace bug (Corythucha ciliata) infected by an unidentified pathogenic fungus were found on the stems of street trees of sycamore in Cheongju city. The objective of this study was to describe this entomopathogenic fungus infecting overwintering sycamore lace bug adults. This unidentified fungus colonized the insect adult body and formed white colony with subglobose clusters of conidiocarps. The size of conidiocarps was 300 to $400{\mu}m$ and each conidium was 15 to $20{\mu}m$. The conidiospore was globus and 2.5 to $3.0{\mu}m$ in diameter, and the hyphae were 1 to $5{\mu}m$ thick. This fungus was successfully isolated and cultivated on potato dextrose agar medium (PDA). The fungal colony was white and then became light yellow. When conidia from this pure culture were inoculated into the overwintering adults, the fungus formed conidiocarps with the same morphology on the insect body and the lethal rate by the fungus was $88{\pm}16%$. This fungus has over 99% homology with Cordyceps bassiana (imperfect fungal name is Beauveria bassiana) in ITS-5.8s rDNA base sequence. The fungal ecology and the infection process of the fungus into its host need to be clarified before using this fungus as a biological control agent.

• KSBB Journal
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• 제23권1호
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• pp.44-47
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• 2008

Anthracycline antibiotics doxorubicin (DXR) is clinically important cancer therapeutic agent produced by Streptomyces peucetius. DXR result by further metabolism of rhodomycin D (RHOD) and require a deoxy-sugar component for their biological activity. In this study, production of TDP-L-daunosamine and its attachment to ${\varepsilon}$-rhodomycinone (RHO) to generate RHOD has been achieved by bioconversion in Streptomyces venezuelae that bears eleven genes. S. peucetius seven genes (dnmUTJVZQS) were transformed by plasmid and S. venezuelae two genes desIII, IV and two more S. peucetius drrA, B genes were integrated into chromosomal DNA. To generate the feeding substrate RHO, 6L S. peucetius grown on agar plate was harvested, extracted with organic solvent and then purified using preparative HPLC. Recombinant S. venezuelae grown on agar plate containing RHO was harvested and its n-butanol soluble components were extracted. The glycosylated product of aromatic polyketide RHO using heterologous host S. venezuelae presents the minimal information for TDP-L-daunosamine biosynthesis and its attachment onto aglycone. Moreover, the structure of auxiliary protein, DnrQ, was predicted by fold recognition and homology modeling in this study. This is a general approach to further expand of new glycosides of antitumor anthracycline antibiotics.

• Journal of Plant Biotechnology
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• 제37권1호
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• pp.77-83
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• 2010

Eighteen cultivars of tomato were tested for their regeneration response. Lycopersicon esculentum cv. 2001-58 showed a very high frequency of regeneration (93%). We evaluated the effect of two compounds with known antioxidant activity (ascorbic acid and cystein). The use of ascorbic acid ($200\;-\;300\;{\mu}M/L$) has a positive effect on shoot regeneration. To develope a system for plastid transformation in tomato via homologous recombination, we constructed the tomato plastid expression vector (pKRT22-AG) harboring 2.2 kb flanking sequences cloned from intact plastid genome and gfp gene. To investigate the factors affecting the delivery system of the pKRT22-AG into chloroplast using bombardment, We assessed the optimal DNA concentration, gold particle volume and target distance. Expression of the GFP protein was observed within chloroplast on protoplast of cotyledon explant by confocal laser scanning microscopy, which indicates that the protocol developed in this study be useful for the production of plastid transgenic plants in tomato.

• Food Science of Animal Resources
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• 제28권1호
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• pp.82-90
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• 2008

Two strains of pure lactic acid bacteria capable of forming both acid and slime were isolated from the kefir made of goat milk. The isolated strains observed by morphological and physiological properties, and their 16S rDNA partial sequence were identified as Streptococcus salivarius subsp. thermophilus(LFG-1) and Lactococcus lactis subsp. lacits(LFG-2) with over 99% homology. The optimum temperature of Str. salivarius subs. thermophilus LFG-1 for growth was $40-45^{\circ}C$, and its generation time was 40.6 minutes. The final pH of cultured broth by Str. salivarius subsp. thermophilus LFG-1 and the commercial strain Str. thermophilus Body-1 for 24hr at $37^{\circ}C$ were 4.30 and 4.55, respectively. The coagulative activity of Str. salivarius subsp. thermophilus LFG-1 was almost as strong as that of commercial strain Str. thermophilus Body-1. However, the LFG-2 strain showed lower coagulative activity than Str. thermophilus Body-1. The survival rate of lactic acid bacteria were between 22-29% in 0.3% bile extract. At pH 1.0 all of the bacteria were killed, and most of lactic acid bacteria died against pH 3.0. However, all lactic acid bacteria survived well at pH 4.5.

• Korean Journal of Microbiology
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• 제40권4호
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• pp.263-268
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• 2004

Two species of halophilic bacteria were isolated from five salted seafoods and identified by 16S rDNA sequenc­ing homology. One was identified as Halomonas subglaciescola and other four strains were belong to Halomo­nas marina. The identity of all isolates with standard organisms was above $95\%.$ H. subglaciescola, H. marina IN, and H. marina SH-2 grew in salinity condition from $3%\;to\;18\%$ NaCl but growth of H. marina SQ and H. marina SH-l grew in salinity environment from $8\%\;to\;17\%.$ Maximum biomass of H. subglaciescola, H. marina IN, H. marina SQ, H. marina SH-1, and H. marina SH-2 growing in LB medium containing $15\%$ NaCl were about 3.2, 4.5, 4.5, 5.7, and 4.2, however the maximum biomass in LB medium containing $5\%$ NaCl were about 2.2, 1.1, 0.7, 0.2, and 2.4 as optical density at 660 nm, respectively. In scanning electron micrograph, unknown material (mucus) attached to outer membrane of all isolates was observed. When mucus isolated from halophilic bacterial cell was added to culture of E. coli, E. coli grew in medium containing $15\%$ NaCl.

• Applied Biological Chemistry
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• 제41권2호
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• pp.125-129
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• 1998

Xanthomonas sp. isolated from soil exhibited cell wall lytic activity of Candida albicans and secreted chitinase in chitin media. Especially, the chitinase activity was induced by chitin and reached a maximum level at 3 days culture in chitin media. We constructed genomic library of Xanthomonas sp. using cosmid vector in E. coli. Oligonucleotide probe was synthesized from the consensus sequence corresponding to chitinase active site, which was derived from the comparison of amino acid sequences of bacterial chitinase genes. Using this oligonucleotide probe, we screened the genomic library. By restriction enzyme mapping of the positive clones, we identified 4 independent clones which may contain the chitinase gene. One of the clones, named pXCH1 (1.2 kb insert), was further analyzed. Northern blot analysis indicated that is transcripts, 1 kb and 0.8 kb, were induced by chitin. When the cloned gene was induced by IPTG in E.coli cell, chitinase activity which was secreted onto culture media was not observed. However, when the cell was disrupted by using sonicator and then centrifuged, the supernatant exhibited chitinase activity. SDS-PAGE of the supernatant indicated that about 35 kDa protein was induced by IPTG. From these results, it was concluded that the cloned DNA was one of the chitinase genes of Xanthomonas sp.

• Korean Journal of Plant Resources
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• 제19권1호
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• pp.54-58
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• 2006

The genetic analyses of Acanthopanax senticosus Harms from Korea, China and Russia, were made by comparing the internal transcribed spacer (ITS) sequences of the nuclear ribosomal DNA. The ITS region of A. senticosus was amplified by polymerase chain reaction (PCR) using the universal primers and then directly sequenced. The length of the ITS region including 162 bp 5.85 rRNA gene ranged from 608 bp (for Korean and Chinese) to 611 bp (for Russian). The G+C content of ITS region were 60.20% for Korean and Chinese plants and 60.06% for Russian plants. Sequence comparisons indicated that ITS regions of A. senticosus from Korea and China were identical, whereas the ITS sequence of A. senticosus from Russia showed 99.2% homology with the plants from Korea. Variation in sequences were attributable to 5 bp substitution such as transversion or insertion events. These results suggested that A. senticosus Harms from Korea and China were closely related in phylogenetic relationship compared to Russian. In addition, A. senticosus Harms were more similar to Kalopanax pictus than A. sessiliflorus in their ITS sequences.

• Development and Reproduction
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• 제10권3호
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• pp.177-184
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• 2006

Retinol-binding protein(RBP) plays an important role in the specific transport of retinol to target cells through the blood stream in higher vertebrates. In order to clarify the effects of 4-nonylphenol(4-NP) on RBP mRNA expression in the rockfish, Sebastes schlegeli which is common in coastal waters of Korea and commercially important species, the cDNA library was constructed from the liver, and a partial fragment of the RBP gene was cloned. The deduced amino acid sequence from the RBP mRNA showed a high homology to the amino acid sequence from Sparus aurata(80%), Oncorhynchus mykiss(72%) or Anguilla anguilla(78%). Effects of 4-NP on RBP and vitellogenin(VTG) mRNA expression level in rockfish were examined by the northern blot analysis. In female and male rockfish injected with 4-NP(10 mg/kg BW, lower dose), there was no changes in the levels of VTG mRNA expression in the liver. The RBP mRNA levels, however, decreased at 48 hours after the injection in male. In the rockfish injected with 4-NP(25 mg/kg BW, higher dose), the level of VTG mRNA expression increased after 24 hours, regardless of sex. The level of RBP mRNA expression decreased at 48 hours after the injection in both sexes. These data indicate that estrogenic mimics such as 4-NP exhibit a contrasting effect on RBP and VTG gene expression in rockfish.

• Korean Journal of Microbiology
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• 제41권4호
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• pp.246-254
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• 2005

Analysis of the complete genome of Neurospora crassa reveals that at least 19 proteins contain tetratricopeptide repeat (TPR) motifs. One of them shows over $60\%$ homology to Ssn6 of Saccharomyces cerevisiae, a universal repressor that mediates repression of genes involved in various cellular processes. Mutant strains generated by RIP (repeat-induced point mutation) process showed four distinctive vegetative growth patterns and slow growth in various rates. Firstly, a mutant showed denser mycelial growth, yellow, csp, and looked like ropy mutant. Secondly, slower growth, dense mycelial, and conidial phenotype. Thirdly, extremely slower growth and aconidial. And finally, flat, tittle aerial hyphae, acon, and similar with a rco-1 RIP mutant. They are all male-fertile, yet female-sterile and produced little or no perithecium. It seems that various phenotypes were occurred depending upon mostly likely, the degree of RIP. These results indicate that this gene may be involved in several cellular possess during vegetative growth, and asexual and sexual development. Therefore it is pleiotropic. Sequence analysis of cDNA shows that it encodes a putative 102 kDa protein composed of 917 amino acids, and has six introns. It is designated rcm-1 (regulation of conidiation and morphology).

• Journal of Life Science
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• 제18권4호
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• pp.482-487
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• 2008

In this study, we screened and identified the bacterial strain showing high alkaline pretense inhibitor activity from marine environment. Nine bacterial strains with alkaline pretense inhibitor activity were isolated from marine sediments. Among them, strain C12 had the highest alkaline pretense inhibitor activity and was selected for further taxonomical study. On the basis of morphological and physiological characteristics, strain C12 was identified as the genus Streptomyces. A phylogenetic analysis of the 165 rDNA showed that the isolated strain was actually a member of the genus Streptomyces, because the determined sequence exhibited a higher homology with Streptomyces thermocarboxydus. Morphological characteristics showed cylindrical spore chain and smooth spore surface by scanning electron microscope. Strain C12 was grown on all media except for ISP 9 agar. This strain could be grown in the medium containing up to 9% NaCl.