• Journal of Microbiology
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• v.34 no.4
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• pp.341-348
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• 1996

The regulation of xylE gene expression was examined by using vector promoter and construction of genetically engineered microorganisms (GEMs) for application in microcosm. When the xylE gene wsa subcloned into pBluscript SK(+) under the control of lac promoter (pTY1) in E. coli, and the expression was induced by IPTG, the enzyme activity of catechol 2, 3-dioxygenase was increased 4.7 times more than that of the crude extracts from transformants harboring pTY1. We suggest that the xylE gene has its own promoter at the upstream portion, because it was able to be expressed even in the absence of IPTG. A recombinant plasmid, pSW3a harboring the xylE gene under the T7 promotor, showed the activity of 14.5 units/mg protein, higher than that of parental strain, E. coli PYT1. The xylE gene in recombinant plasmid pSW3a was used as reporter gene for the application in microcosm ecosystem, since it was used for detection of xylE-positive clones by catechol spray on the agar plates. The pSW3a in E. coli was introduced into Pseudomonas patida to construct GEM strain, and examined for the exxpression and functional stability in microcosms.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.230-232
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• 2005

The formation of insoluble aggregation of the recombinant kringle fragment of human apolipoprotein(a), rhLK8, in endoplasmic reticulum was identified as the rate-limiting step in the rhLK8 secretion in Saccharomyces cerevisiae. To analyze the protein secretion pathway, some of yeast genes closely related to protein secretion was rationally selected and their oligomer DNA were arrayed on the chip. The expression profiling of these genes during the induction of rhLK8 in fermentor fed-batch cultures revealed that several foldases including pdi1 gene were up-regulated in the early induction phase, whereas protein transport-related genes were up-regulated in the late induction phase. The coexpression of pdi1 gene increased rhLK8-folding capacity. Hence, the secretion efficiency of rhLK8 in the strain overexpressing pdi1 gene increased by 2-fold comparing in its parental strain. The oligomer DNA chip arrayed with minimum number of the genes selected in this study could be generally applicable to the monitoring system for the heterologous protein secretion and expression in Saccharomyces cerevisiae. With the optimization of fed-batch culture conditions and the alteration of genetic background of host, we obtained extracellular rhLK8 at higher yields than with Pichia pastoris systems, which was a 25-fold increased secretion level of rhLK8 compared to the secretion level at the initiation of this study.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.2
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• pp.107-110
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• 2001

Variations in protein and nucleic acid concentrations were observed in 24 hrs old eggs and hatched larvae of Nistari strain, Bombyx mori, exposed to starvation. Three starvation treatments of 24,48 and 60 hrs were given separately from 0 hr old fifth instar larvae. Biochemical variations were studied in the resultant hatched larvae of one time starved parent, while the eggs obtained from parents receiving starvation in two successive generations were considered for the study. In hatched larvae, protein levers in 24 hrs starvation groups remained significantly higher over control (never starved) while the same was found to be lower in 48 and 60 hrs starvation individuals. The RNA concentration remained significantly higher in all the treated lots. However, DNA content was not found to be significantly altered in hatched larvae after exposure to feeding stress. Protein, RNA and DNA concentration of 24 hrs old eggs produced by all the starved groups of Nistari, which had deceived two consecutive starvation during parental generations, showed higher concentrations of these biomolecules over control. Hence, starvation induced alterations in protein and nucleic acids in eggs and hatched Iarvae are indicative of a preparatory phase adopted by the insect to acclimatise itself and its progeny to stress situations.

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.1-6
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• 2002

$\alpha$-Amylase producing bacteria were isolated from activated sludge of corn processing wastewater plant and paddy field soil samples and selected by the direct iodine reaction. The isolate was identified as Bacillus sp. after morphology, API system and fatty acid analyses. To enchance $\alpha$-amylase productivity, a successive mutation of Bacillus sp. AIV 19 was performed using the treatment of nitrosoguanidine(NTG).The mutant, Bacillus sp. AIV 1940, showed about 1.8-fold level of amylase activity compared with parental strain. The isolate was Gram-positive and rod (2.8-3.0 $\mu$m long, 0.5-0.6 $\mu$m wide) type. The strain increased the bacterial mass at 3000 mg/l starch concentration. Organic substance removal rate was 40.2, 72.3% respectively after 1 and 3 day reaction using starch synthetic wastewater (intial CODcr was 4,455 mg/l).

• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.311-318
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• 1986

Glucoamylase and ethanol productivities of HSDD-170 and HSDM-119 formed by S. cerevisiae and S. diastaticus protoplast fusion were investigated. For the production of the glucoamylase, soluble starch as carbon source, yeast extract and C. S. L as nitrogen source added into the basal medium were favorable. The production of the enzyme reached at maximum after cultivation of the fusant for 4 days at 3$0^{\circ}C$, aerobically. The properties of glucoamylase produced by fusants were very similar to those produced by S. diastaticus as based on optimum temperature, pH stability. In alcohol fermentation from starch, strain HSDD-170 fermented starch faster than either of its parental strains. The maximum of alcohol yield in 15% of liquefied potato starch was 7.5% (v/v).

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1591-1600
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• 2021

Streptomyces coelicolor is a filamentous soil bacterium producing several kinds of antibiotics. S. coelicolor abs8752 is an abs (antibiotic synthesis deficient)-type mutation at the absR locus; it is characterized by an incapacity to produce any of the four antibiotics synthesized by its parental strain J1501. A chromosomal DNA fragment from S. coelicolor J1501, capable of complementing the abs- phenotype of the abs8752 mutant, was cloned and analyzed. DNA sequencing revealed that two complete ORFs (SCO6992 and SCO6993) were present in opposite directions in the clone. Introduction of SCO6992 in the mutant strain resulted in a remarkable increase in the production of two pigmented antibiotics, actinorhodin and undecylprodigiosin, in S. coelicolor J1501 and abs8752. However, introduction of SCO6993 did not show any significant difference compared to the control, suggesting that SCO6992 is primarily involved in stimulating the biosynthesis of antibiotics in S. coelicolor. In silico analysis of SCO6992 (359 aa, 39.5 kDa) revealed that sequences homologous to SCO6992 were all annotated as hypothetical proteins. Although a metalloprotease domain with a conserved metal-binding motif was found in SCO6992, the recombinant rSCO6992 did not show any protease activity. Instead, it showed very strong β-glucuronidase activity in an API ZYM assay and toward two artificial substrates, p-nitrophenyl-β-D-glucuronide and AS-BI-β-D-glucuronide. The binding between rSCO6992 and Zn²⁺ was confirmed by circular dichroism spectroscopy. We report for the first time that SCO6992 is a novel protein with β-glucuronidase activity, that has a distinct primary structure and physiological role from those of previously reported β-glucuronidases.

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1384-1389
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• 2023

This work aimed to evaluate the feasibility of biohydrogen production from Barley Straw and Miscanthus. The primary obstacle in plant biomass decomposition is the recalcitrance of the biomass itself. Plant cell walls consist of cellulose, hemicellulose, and lignin, which make the plant robust to decomposition. However, the hyperthermophilic bacterium, Caldicellulosiruptor bescii, can efficiently utilize lignocellulosic feedstocks (Barley Straw and Miscanthus) for energy production, and C. bescii can now be metabolically engineered or isolated to produce more hydrogen and other biochemicals. In the present study, two strains, C. bescii JWCB001 (wild-type) and JWCB018 (ΔpyrFA Δldh ΔcbeI), were tested for their ability to increase hydrogen production from Barley Straw and Miscanthus. The JWCB018 resulted in a redirection of carbon and electron (carried by NADH) flow from lactate production to acetate and hydrogen production. JWCB018 produced ~54% and 63% more acetate and hydrogen from Barley Straw, respectively than its wild-type counterpart, JWCB001. Also, 25% more hydrogen from Miscanthus was obtained by the JWCB018 strain with 33% more acetate relative to JWCB001. It was supported that the engineered C. bescii, such as the JWCB018, can be a parental strain to get more hydrogen and other biochemicals from various biomass.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.151-156
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• 1994

Pseudomonas fluorescens produces the antibiotic, 2,4-diacetylphloroglucinol (Phl), which promotes plant growth by inhibiting bacteria and fungi. Cosmids (genomic library) were mobilized into Phl-nonproducing mutants through the triparental matings with pRK2013 as the helper plasmid at the frequency of 8.37$\times$10-4. Complemented mutants that showed antibiotic activity were selected among about 2,000 transconjugants. The complemented mutants were confirmed by acquired drug resistances (kanamycin and tetracycline). The antibiotic substances of wild type and complemented mutants showed the most excellent anti-bacterial activity. Inhibitory effects of complemented P. fluorescens against phytopathogenic fungi were equal to the parental strain. Complemented mutant and wild type of P. fluorescens were causal microbes of fungal morphological abnormalities. Complemented mutants in potato dextrose agar supplemented with bromothymol blue also showed restoration of glucose utilization as wild type. Plasmids of complemented mutants were isolated from transconjugant sand transformed into competent cells of E. coli DH5$\alpha$. The plamid DNA was reisolated from transformed E. coli DH5$\alpha$.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.787-791
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• 2005

Mutation and its pilot-scale fermentation were conducted for the production of teicoplanin from Actinoplanes teichomyceticus. The fermentation medium was optimized by replacement and Plackett-Burman experimental design. A maximum production of 1,500 mg/l teicoplanin was obtained by pilot-scale fermentation in an optimized medium containing (g/l): 30 g maltodextrin, 5 g glucose, 5 g yeast extract, 5 g soybean meal, 0.5 g $MgSO_4{\cdot}7H_2O$, 0.1 g NaCl, 0.1 g $CaCl_2{\cdot}2H_2O$, and 50 g Diaion HP-20. The production of teicoplanin was improved 3-fold from the parental strain by mutation, media optimization, and fermentation, and laboratory-scale fermentation was successfully demonstrated in a pilot-scale fermenter for the industrial production of teicoplanin.

• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.182-186
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• 1988

The possibility of strain improvement of cellulolytic fungus, Penicillium verruculosum via protoplast fusion was investigated. The cellulolytic activities of the six fusants, finally selected for their hyper-cellulolytics were 2 times of those of wild type and 1.2 to 4.4 times of those parental auxotrophs. It was confirmed that the nuclear fusion occurred in fusants by their DNA contents and nuclear staining with Giemsa. It was also found that the fusants were aneuploids, and their genetic stability was demonstrated from the subculture for four months.