• KSBB Journal
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• v.13 no.6
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• pp.662-668
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• 1998

Viruses belonging to the Hantavirus genus cause two acute severe illness in humans, i.e., Haemorrhagic Fever with Renal Syndrome (HFRS) and Hantavirus Pulmonary Syndrome(HPS). Among them, Hantaan virus is one of the most important viruses causing HFRS. Recombinant expression vectors, pKK-NP and pET-NP, with Hantaan viral nucleocapsid gene were constructed, and used to transform Eschericia coli BL21(DE3). Stability of the vectors in the host strain, and effects of some environmental conditions on the expression of nucleocapsid gene were studied. Expression vector, pKK-NP, was very unstable, and the expression level of nucleocapsid gene was very low compared to that of pET-NP. BL21(pET-NP) produced about 100 mg of N protein per liter of culture broth. Induction time did not show any significant difference on the expression level of nucleocapsid gen and cell growth. BL21(pET-NP) culture at 35$^{\circ}C$ showed a little higher expression level than at 30$^{\circ}C$ during growth phase, but reached to the same level at stationary phase. Total expression level was proportional to supplemented glucose concentration of media up to 0.5% along with cell growth, but expression level per unit cell mass was inversely proportional to glucose concentration and maximal when glucose was not supplemented at all.

• 보존과학연구
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• s.13
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• pp.96-112
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• 1992

We made biological investigation on the conservational environment of collections in the Ho Am museum. Annual average temperature and relative humidity outside the museum were $11. 0∼11.7^{\circ}C$ and 64.8∼74.4% respectivey. On the other hand, average annual temperature and relative humidity inside the main storage were $19.1∼20.1^{\circ}C$ and 53.0∼63.4%. We isolated fungi and classified into 8 genus 13species fungi and selected four fungi having high cellulotic activity such as Alternaria brassicae KCPRI 9202, Aspergillus niger KCPRI 9205, Aspergillusversicolor KCPRI 9206, Penicillium adametzi KCPRI 9208. These fungi were examined on the posibility of collections being damaged under current conservation al environment in the museum. KCPRI 9208 was non-tonophilic fungus and other were facutative tonophilic fungi. These showed maximal cellulotic activity of enzymeshaking culture at pH 5.0∼5.5 for 4 and 5 days. In proprtion to the period damaged, cellulase activity for paper damaged artifically with growing worse of material. As are sult cellulotic activity by fungi increased.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.279-285
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• 2002

Phytase (myo-inositol hexakisphosphate phospho-hydrolase, EC 3.1.3.8) catalyzes the hydrolysis of phytate (myo-inositol hexakisphosphate) to release inorganic phosphate. A bacterial strain producing phytase was isolated from soil around a cattle shed. To identify the strain, cellular fatty acids profiles, the GC contents, a quinine-type analysis, and physiological test using an API 20NE kit were carried out. The strain was identified to be a genus of Pseudomonas sp. and named as Pseudomonas sp. YH40. The optimum culture condition for the maximum productivity of phytase by Pseudomonas sp. YH40 were attained in a culture medium composed of $1.0\%$ (w/v) glycerol, $2.0\%$ (w/v) peptone, and $0.2\%$ (w/v) $FeSO_4{\cdot}7H_2O$. Within the optimal medium condition, the production of phytase became highest after 10 h of incubation, and the maximal phytase production by Pseudomonas sp. YH40 was observed at $37^{\circ}C$ and pH 6.0.

• Biomedical Science Letters
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• v.27 no.4
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• pp.277-282
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• 2021

Hydrocotyle is a genus of prostrate, perennial aquatic or semi-aquatic plants formerly classified in the family Apiaceae, now in the family Araliaceae. Lipoxygenases (LOX) are present in the human body and play an important role in the stimulation of inflammatory reactions. Ethanolic extracts of five Hydrocotyle species (H. ramiflora, H. maritima, H. nepalensis, H. sibthorpioides, and H. yabei) showed inhibition of 23.5~50.6% at 2.0 mg/mL. Their extracts showed LOX inhibition in half maximal effective concentration (EC₅₀) range 15.1~15.7 ㎍/mL. Hyaluronic acid is a glycosaminoglycan, a major component of the extracellular matrix Five extracts of these species inhibited less than 23.0% of Hyaluronidase (HAase) activity at a concentration of 2.0 mg/mL Xanthine oxidase (XO) is a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species. Five Hydrocotyle species were found to have inhibitory activity of XO at 2.0 mg/ml, with 65% having greater than 50% inhibition. H. ramiflora exhibited the highest activity with an inhibition of 80.0%. The results suggested that Lipoxygenases, Hyaluronidase, and Busan 47340, Republic of Korea from five Hydrocotyle species might be multifunctional and prevent the degradation of allergic reactions and inflammation.

• Mycobiology
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• v.51 no.3
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• pp.157-163
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• 2023

Cordyceps fumosorosea is an important species in the genus of Cordyceps, containing a variety of bioactive compounds, including fumosorinone (FU). This study was a ground-breaking assessment of FU levels in liquid and solid cultures. The present study focused on the impacts of solid-state fermentation (SSF) using solid substrates (wheat, oat, and rice), as well as the effects of fermentation parameters (pH, temperature, and incubation period), on the generation of FU. All the fermentation parameters had significant effects on the synthesis of FU. In a study of 25 ℃, 5.5 pH, and 21 days of incubation period combinations calculated -to give maximal FU production, it was found that the optimal values were 25 ℃, 5.5 pH, and 21 days, respectively. In a solid substrate medium culture, FU could be produced from SSF. At 30 days, a medium composed of rice yielded the most FU (798.50 mg/L), followed by a medium composed of wheat and oats (640.50 and 450.50 mg/L), respectively. An efficient method for increasing FU production on a large scale could be found in this approach. The results of this study might have multiple applications in different industrial fermentation processes.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.102-110
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• 2018

A bacterial strain capable of metabolizing myo-inositol (MI) and converting to other substances was isolated from soil of orchard. The isolate, named YB-46, was grown on minimal medium supplemented with MI as the sole carbon source and was presumed to belonging to genus Enterobacter according to the 16S rDNA sequence. Escherichia coli transformant converting MI into unknown metabolites was selected from a metagenomic library prepared with fosmid pCC1FOS vector. Plasmid was isolated from the transformant, and the inserted gene was partially sequenced. From the nucleotide sequence, an iolG gene was identified to encode myo-inositol dehydrogenase (IolG) consisting of 336 amino residues. The IolG showed amino acid sequence similarity of about 50% with IolG of Enterobacter aerogenes and Bacillus subtilis. The His-tagged IolG (HtIolG) fused with hexahistidine at C-terminus was produced and purified from cell extract of recombinant E. coli. The purified HtIolG showed maximal activity at $45^{\circ}C$ and pH 10.5 with the highest activity for MI and D-glucose, and more than 90% of maximal activity for D-chiro-inositol, D-mannitol and D-xylose. $K_m$ and $V_{max}$ values of the HtIolG for MI were 1.83 mM and $0.724{\mu}mol/min/mg$ under the optimal reaction condition, respectively. The activity of HtIolG was increased 1.7 folds by $Zn^{2+}$, but was significantly inhibited by $Co^{2+}$ and SDS.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.272-278
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• 2007

Proteases are enzymes that break peptide bonds between amino acids of other proteins and occupy a crucial position with respect to their applications in both physiological and commercial fields. In order to screen new source of protease, bacteria producing extracellular proteases at low temperature were isolated from deep sea water of East Sea, Korea. A bacterium showing the best growth rate and production of an extracellular protease at low temperature was designated HJ 47. The DNA sequence analysis of the 16S rRNA gene, phenotypic tests and morphology led to the placement of this organism in the genus Pseudoalteromonas. Although maximal growth was observed at $37^{\circ}C$, enzyme production per culture time was maximum at $20^{\circ}C$. At this temperature, extracellluar protease production was detected from the end of the exponential phage to stationary phase, and maximal at 15 hours after initial production. The optimum temperature and pH of the protease were found to be $35^{\circ}C$ and 8.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.364-373
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• 2015

As an effort to utilize alginate, 103 bacterial isolates that were positive for the alginate lyase activity were isolated from various clams and seawater samples collected in Incheon coastal area. Among them, 3 strains (M1-2-1, M6-1, and C8-15) were finally selected for further analysis based on their activities at higher levels than others. These isolates were all Gram-negative and rod shaped halophilic bacteria with motility. According to their physiological and biochemical properties as well as DNA sequence of their 16S rRNA genes, M1-2-1 and M6-1 were identified as a member of genus Pseudoalteromonas and C8-15 belonged to genus Vibrio. They exhibited the alginate degrading activity at the maximal level when they were cultured in APY broth for 6-8 h at $25^{\circ}C$. Both their growth and the enzyme activity were greatly enhanced when NaCl was added to the growth medium. The crude alginate lyases from the supernatants of the bacterial cultures showed the highest activity at $45^{\circ}C$ and pH 7.0-8.0. M1-2-1 and M6-1 produced 2.723 and 1.976 g/L of reducing sugar from alginate, respectively, suggesting that they have potential for commercial application.

• ALGAE
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• v.19 no.2
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• pp.145-148
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• 2004

As a result of the 2-year monthly monitoring of the phytoplankton community at 3 stations in Mankyeong Estuary, Korea, we learned that cyan bacterial species of the genus Anabaena occurred at most sampling points with huge salinity differences (0.1-32.5 psu). We isolated several clones of Anabaena spp. from the monitoring stations, and screen out two euryhaline and nitrogen-fixing Anabaena clones, CB-MAL21 and CB-MAL22. The two clones were grown under various environmental gradients such as temperature (20, 30, 35 and 40$^{\circ}C$), salinity (0, 2, 5, 15 and 30psu), and $PO_4^{3-}$-P concentration (0, 1.6, 8.0, 40 and 200 ${\mu}M$M). Growth of CB-MAL21 and CB-MAL22 was measured by daily monitoring of chlorophyll fluorescence from each experimental culture for more than three serial transfers. Both the two experimental clones did not grow at 0psu. Maximal growth rates of the two clones were markedly reduced at lower $PO_4^{3-}$-P concentrations showing negligible growth at 0 and 1.6 ${\mu}M$M. However, growth of CB-MAL21 was not affected by low $NO_3^--$ concentration in culture media, showing the nitrogen-fixing ability. Maximum biomass yields of the two clones decreased dramatically at 35 and 40$^{\circ}C$. Optimal growth conditions for the two experimental clones were determined to be 20-30$^{\circ}C$, 40 ${\mu}M$M $PO_4^{3-}$-P, and wide salinity range from 5.0 to over 30psu. Best growth of CB-MAL21 was shown at (20$^{\circ}C$-15psu), which is less saline and cooler condition than those (i.e., 30$^{\circ}C$-30psu) for the best growth of CB-MAL22. The euryhaline and nitrogen-fixing CB-MAL21 strain thus can be a candidate laboratory culture for the future cyan bacterial marine biotechnology in temperate coastal waters.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.373-382
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• 1994

A bacterial strain No. 40, which produced extracellular endoglucanase, was isolated from the rumen of Korean native goals and identified to be a genus of Actinomyces sp. The optimum conditions for endoglucanase production in PY-CMC medium were initial pH of 7.0 and 4 days of cultivation at $39^{\circ}C$. When localization of endoglucanase activity of Actinomyces sp. was determined, 68% of the enzyme activity was found in the extracellular fraction, 11% of the activity was detected in the periplasmic space and the remaining activity was in the intracellular and cell-bound fractions. The maximal endoglucanase activity was observed at pH 5.0 and it was most s table at pH 5.0. The optimum temperature of this enzyme activity was $55^{\circ}C$, but enzyme activity was gradually lost at temperature above $60^{\circ}C$. The crude enzyme was activated by addition of 10 mM cysteine and 10 mM DTT. But it was inhibited by addition of 10 mM $Cu^{{+}{+}}$ and $Fe^{{+}{+}}$. This crude enzyme could digest carboxymethylcellulose (CMC), and degrade xylan, avicel, pNPG, and pNPC to a less extent.