• KSBB Journal
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• v.22 no.5
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• pp.288-296
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• 2007

Monascus pilosus (KCCM 60160) in submerged culture was optimized based on culture medium and fermentation conditions. Monacolin-K (Iovastatin), one of the cholesterol lowing-agent which was produced by Monascus pilosus may maintain a healthy lipid level by inhibiting the biosynthesis of cholesterol. Plackett-Burman design and response surface method were employed to study the culture medium for the desirable monacolin-K production. As a result of experimental designs, optimized production medium components and concentrations (g/L) were determined on soluble starch 96, malt extract 44.5, beef extract 30.23, yeast extract 15, $(NH_4)_2SO_4$ 4.03, $Na_2HPO_4{\cdot}12H_2O$ 0.5, L-Histidine 3.0, $KHSO_4$ 1.0, respectively. Monacolin-K production was improved about 3 times in comparison with shake flask fermentation of the basic production medium. The effect of agitation speed (300, 350, 400 and 450 rpm) on the monacolin-K production were also observed in a batch fermenter. Maximum monacolin-K production with the basic production medium was 68 mg/L when agitation speed was 500 rpm. And it was found that all spherical pellets (average diameter of $1.0{\sim}1.5mm$) were dominant during fermentation. Based on the results, the maximum production of 185 mg/L of monacolin-K with the optimized production medium was obtained at pH (controlled) 6.5, agitation rate 400 rpm, aeration rate 1 vvm, and inoculum size 3%.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1714-1718
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• 2002

Twelve prepubertal Karan Fries heifers (15 months, $167.7{\pm}13.5kg$) were divided into two equal groups. Group 1 was fed as per NRC requirements and group 2 was fed 20% more protein than group 1 heifers. The experimental feeding was continued until the onset of puberty in both the groups. Blood samples were collected at fortnightly intervals and analyzed for amino acids using HPLC. Group 1 and 2 heifers required $178.6{\pm}33.8$ and $152.8{\pm}33.2$ days of experimental feeding to exhibit first estrus resulting in total age at puberty as $639.4{\pm}27.3$ and $618.6{\pm}24.6$ days in the two groups respectively. The concentration of total amino acids averaged 4.40 and 4.89 mmol/l and those of non-essential amino acids (NEAA) was 2.32 and 2.49 mmol/l in groups 1 and 2, respectively. The concentration of plasma essential amino acids i.e. histidine, threonine, valine, methionine, isoleucine, leucine and phenylalanine were higher (p<0.01) in group 2 than group 1. Plasma concentration of large neutral amino acids (LNAA) was significantly higher in group 2 (1.28 mmol/l) than in group 1 (1.12 mmol/l). Increased levels of leucine, isoleucine and valine are implicated in increased follicular growth and development in prepubertal heifers and resulted in a 26 day earlier attainment of puberty by 26 days in an experimental period of six months in group 2 heifers. Increased concentrations of aspartate and tyrosine in group 2 heifers might be associated with the release of GnRH from the hypothalamus influencing LH release from anterior pituitary in such animals. It is therefore evident that increased availability of certain amino acids in heifers fed high protein diet might have led to early onset of puberty.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.450-464
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• 2004

Background : The FHIT (fragile histidine triad) gene is a frequent target of deletions associated with abnormal RNA and protein expression in lung cancer. Previous studies have shown FHIT gene transfer into lung cancer cell line lacking FHIT protein expression resulted in inhibition of tumor cell growth attributable to the induction of apoptosis and reversion of tumorigenecity. However, the mechanism of the tumor suppressor activity of the FHIT gene and the cellular pathways associated with its function are not completely understood. Methods : To gain insight into the biological function of FHIT, we compared the NCI-H358 cell line with its stable FHIT transfectants after treatment with cisplatin or paclitaxel. We investigated the effects of FHIT gene expression on cell proliferation, apoptosis, and activation of caspase system and Bcl-2 family. The induction of apoptosis was evaluated by using DAPI staining and flow cytometry. Activation of caspases and Bcl-2 members was evaluated by Western blot analysis. Results : A significantly increased cell death was observed in FHIT transfectants after cisplatin or paclitaxel treatment and this was attributable to the induction of apoptosis. Remarkable changes in caspases and Bcl-2 family were observed in the transfected cells as compared with the control cells after treatment with paclitaxel. Activation of caspase-3 and caspase-7 was markedly increased in cells expressing FHIT. Expression level of Bcl-2 and Bcl-xL protein was significantly decreased and that of Bax and Bad protein was significantly increased in the transfected cells. Conclusion : FHIT gene delivery into lung cancer cells results in enhanced apoptosis induced by treatment with cisplatin or paclitaxel. The data suggest that apoptosis in FHIT-expressing cells could be related to activation of caspase pathway and Bcl-2 family.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.55-60
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• 1997

Heavy metal-tolerant microorganisms, such as Pseudomonas putida, P. aeruginosa, P. chlororaphis and P. stutzeri which possessed the ability to accumulate cadmium, lead, zinc and copper, respectively, were isolated from industrial wastewaters and mine wastewaters polluted with various heavy metals. The distribution of heavy metal in the cell components, and amino acid compositions, was investigated. The distribution of heavy metal in the cell fractions of each heavy metal-tolerant microorganism grown for 20 hours in the basal medium containing 100mg/l of each heavy metal was investigated. In the case of cadmium-tolerant P. putida, lead-tolerant P. aeruginosa and copper-tolerant P. stutzeri, approximately $50{\sim}60%,\;30{\sim}40%$ and $10{\sim}17%$ of each heavy metal absorbed were distributed to cell wall, cell membrane and cytoplasm fractions, respectively. In the case of zinc-tolerant P. chlororaphis, approximately 32%, 55% and 13% of zinc were distributed to cell wall, cell membrane and cytoplasm fractions, respectively. These results indicated that the cell wall was a major adsorbing fraction of cadmium, lead and copper, and the cell membrane was that of zinc. Total amino acid content per gram of the cell grown in the culture media with heavy metal was higher than that of the cell grown in the culture media without heavy metal, and the content of acidic amino acids, such as aspartic acid(Asp.+Asn.) and glutamic acid(Glu.+Gln.) was higher than that of basic amino acids, such as histidine, lysine and arginine.

• Journal of Dairy Science and Biotechnology
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• v.23 no.2
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• pp.93-98
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• 2005

Effects of heat and gamma irradiation on chemical, microbiological, and immunological changes of raw milk were compared. Free fatty acid content of milk showed increasing tendency according to the increase of heating temperature and irradiation dose, and showed similarity in UHT (ultra high temperature) and 5 kGy irradiation. Total bacterial counts and coliforms were not detected after treatment of LTLT (low temperature long time), HTST (high temperature short time), UHT, and irradiation from 1 to 10 kGy in the milk with initial microbial load at $10^3$ CFU/mL initially, but after 7 day storage, were not detected in UHT milk and that irradiated at 3 kGy or above. Heat treatment decreased (p<0.05) arginine, asparate, iso-leucine, lysine, and methionine content compared to raw milk while irradiation decreased (p<0.05) asparate, histidine, iso-luecine, leucine, and lysine content, which means irradiation could change primary structure of milk proteins. It was concluded that f kGy gamma irradiation treatment of raw milk could give a similar effect to UHT treatment in chemical and microbiological viewpoint, and may reduce allergenicity of raw milk.

• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.196-201
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• 2012

Microorganisms, having the lower decarboxylase activity, among the isolated strains from $cheonggukjang$ and rice-straw in this study were selected by using biogenic amine (BA) media. The selected strains were identified as $Bacillus$ $subtilis$ HH12, $B.$ $subtilis$ HR254, and $Paenibacillus$ $barcinonensis$ KR97, by using 16S rRNA analysis. PCR analysis showed that the histidine decarboxylase ($hdc$) gene was absent in the HH12, HR254, and KR97 strains. However, PCR analysis showed that the tyrosine decarboxylase ($tdc$) gene was present in the HH12, HR254, and KR97 strains. Quantitative analysis of the selected strains by using high-performance liquid chromatography showed that histamine was absent in the HH12, HR254, and KR97 strains. However, these 3 strains showed tyramine concentrations of 6.09, 3.68, and 6.30 mg/L, respectively. These strains produced lower concentrations of amines (approximately 7.9, 0, and 9.3% amines in the HH12, HR254, and KR97 strains, respectively) than the $B.$ $subtilis$ MC138 strain, which showed the higher protease activity.

• KSBB Journal
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• v.6 no.4
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• pp.327-336
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• 1991

A study on the optimum hydrolysis conditions of fish skin through the aid of enzymes and the development of a natural seasoning using the hydrolysate has been carried out for the effective utilization of fish skin. Using the "pH-drop" techniques the collagenase and pronase were identified as most suitable for this purpose. The $K_m$ and $V_{max}$ values of pronase were 1.82 mgN/ml and 0.06 mgN/mL/min, respectively. The hydrolysis conditions of the cod skin for the pronase were as follows: reaction temperature, $50^{\circ}C$; reaction time, 3hrs; pH 6; enzyme concentration, 0.03%. The degree of hydrolysis at these conditions was 76.8%. But after hydrolyzing cod skin with collagenase for 1hr, when the pronase was treated, the degree of hydrolysis was 83.13%. The molecular weight of the hydrolysate was 8,000 daltons. Among the amino acids in the hydrolysate, glycine(27.95%), glutamic acid(10.94%), proline(7.39%), aspartic acid(9.47%) and serine(7.39%) were responsible for 64.23% of the total amino acids. But valine, methionine, isoleucine, leucine, phenylalanine and histidine having a bitter taste were only 13.05%. From the results of the sensory evaluation, the imitation sauce which was made of 20% fermented soy sauce prepared from the hydrolysate was at least similar to the traditional soybean sauce in product quality. The complex seasoning containing 31.7% of the hydrolysate was nearly equal to complex seasonings on the market, too.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1158-1167
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• 2000

To produce ${\beta}-cyclodextrin({\beta}-CD)$, a cyclodextrin glucanotransferase(CGTase) producing Aspergillus sp. CC-2-1 was isolated from soil. The enzyme was purified and its enzymological characteristics were investigated. It was found that production of CGTase reached to the maximum when the wheat bran medium containing 0.1% albumin, 2% $(NH_4)_2S_2O_8$, 2% soluble starch and 0.2% $KH_2PO_4$ was cultured for 5 days at $37^{\circ}C$. The purity of CGTase was increased by 13.14 folds after DEAE-cellulose ion exchange chromatography and Sephadex G-100, G-150 gel filtration and the specific activity was 172.14 unit/mg. Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. The molecular weight of CGTase was estimated to be 27,800 by Sephadex G-100 gel filtration and SDS-polyacrylamide gel electrophoresis. The optimum pH and temperature for the CGTase activity were 9.0 and $80^{\circ}C$, respectively. The enzyme was stable in pH $8.0{\sim}11.0$ at $60{\sim}80^{\circ}C$. The activity of purified enzyme was activated by $K^+,\;Cu^{2+}$ and $Zn^{2+}$. The activity of the CGTase was inhibited by the treatment with 2,4-dinitrophenol and iodine. The result suggests that the purified enzyme has phenolic hydroxyl group of tyrosine, histidine imidazole group and terminal amino group at active site. The reaction of this enzyme followed typical Michaelis-Menten kinetics with the $K_m$ value of 18.182 g/L with the $V_{max}$ of 188.68 ${\mu}mole/min$. The activation energy for the CGTase was calculated by Arrhenius equation was 1.548 kcal/mol.

• Research in Plant Disease
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• v.30 no.2
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• pp.148-156
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• 2024

Ralstonia pseudosolanacearum, a plant pathogenic bacterium that can survive for a long time in soil and water, causes lethal wilt in the Solanaceae family. Sigma S is a part of the RNA polymerase complex, which regulates gene expression during bacterial stress response or stationary phase. In this study, we investigated the role of sigma S in R. pseudosolanacearum under stress conditions using a rpoS-defective mutant strain of R. pseudosolanacearum and its wild-type strain. The phenotypes of rpoS-defective mutant were complemented by introducing the original rpoS gene. There were no differences observed in bacterial growth rate and exopolysaccharide production between the wild-type strain and the rpoS mutant. However, the wild-type strain responded more sensitively to nutrient deficiency compared to the mutant strain. Under the nutrient deficiency, the rpoS mutant maintained a high bacterial viability for a longer period, while the viability of the wild-type strain declined rapidly. Furthermore, a significant difference in pH was observed between the culture supernatant of the wild-type strain and the mutant strain. The pH of the culture supernatant for the wild-type strain decreased rapidly during bacterial growth, leading to medium acidification. The rapid decline in the wild-type strain's viability may be associated with medium acidification and bacterial sensitivity to acidity during transition to the stationary phase. Interestingly, the rpoS mutant strain cannot utilize acetic acid, D-alanine, D-trehalose, and L-histidine. These results suggest that sigma S of R. pseudosolanacearum regulates the production or utilization of organic acids and controls cell death during stationary phase under nutrient deficiency.

• Journal of Life Science
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• v.19 no.2
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• pp.277-283
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• 2009

Biogenic amines are generally formed through the decarboxylation of specific free amino acids by exogenous decarboxylases released by microbial species associated with the fish products and fermented feeds. This study was conducted to investigate the properties of e tuna waste regarding the control of degradation of biogenic amines (histamine, tyramine, tryptamine, putrescine, and cadaverine) that might be related with the anti-nutritional factor of the tuna waste that is used for manufacturing domestic fish meal. The values of pH and the salt content were 6.51, 3.35% in tuna waste and 5.58 and 5.83% in tuna fish meal, respectively. The strains and dominant bacteria tested in the tuna waste sample were 9.20, 9.29, 5.67, 7.82 and 7.58 log CFU/g of total bacteria, aerobic plate count (APC), total coliform (TC), Lactobacillus spp. and Bacillus spp., respectively. The main histamine forming-bacteria (HFB) in tuna waste were detected by silica gel thin-layer chromatography (TLC) and 7 histamine-forming bacterial species were isolated among microbes grown in selective medium. The histamine concentration was determined by detection of fluorescence of ο-phthaldialdehyde (OPA) derivatives using HPLC and the date were used to reconfirm the identities of the amine-producing bacteria. The 15 histamine- forming bacteria strains grown in trypicase soy broth (TSB) supplemented with 1% L-histidine (TSBH) were identified as Lactococcus(L.) lactis subsp. lactis, Klebsiella pneummonlae, L. garvieae 36, Vibrio olivaceus, Hafnia alvei and L. garvieae which were main dominant amine - producing strains, and Morganella morganii identified by 16S ribosomal RNA (rRNA) sequencing with PCR amplification. A Phylogenetic tree generated from the 16S rRNA sequencing data showed different phyletic lines that could be readily classified as biogenic amine forming gram-positive and negative bacteria.