• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.10
• /
• pp.1378-1382
• /
• 2004

Zinc (Zn) is a micromineral and functions as a cofactor of many enzymes and its deficiency induces retardation of growth and dysfunction of the immune system in animals. This study was conducted to determine lipogenic activity of Zn in bovine intramuscular adipocytes. Preadipocytes were isolated from intramuscular fat depots of 26 month old Korean (Hanwoo) steers and cultured in media containing Zn. At confluence, the cells were treated with insulin, dexamethasone, and 1-methyl-3-isobutyl-xanthine to induce differentiation (accumulation of lipid droplets in cells). The sources of Zn were zinc chloride (${ZnCl}_2$) and zinc sulfate (${ZnSO}_4$), and the final concentrations of both Zn sources were 0, 5, 25, 50 and 100 ${\mu}$M. Glycerol-3-phosphate dehydrogenase (GPDH) activity, an index of adipocyte differentiation, was increased as the concentration of Zn in media increased showing the highest activity (25.74 ng/min/mg protein) at 25 ${\mu}$M of ${ZnSO}_4$. Supplementation of Zn during differentiation of bovine intramuscular adipocytes tended to decrease the production of nitric oxide (NO). Peroxisome proliferator-activated receptor gamma 2(PPAR$\gamma$2) gene expression was increased 10 days after differentiation induction. The current results indicate that Zn has a strong lipogenic activity in cultured bovine intramuscular adipocytes with remarkable suppression of NO production.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.252-252
• /
• 1994

현재 시판되고 있는 정장용 생균 제제에 함유되어있는 정장균주의 하나인 Bifidohacterium bifidum은 항결핵제 중 rifampicin에 감수성으로 rifimpicin과 병용 투여시 본래의 정장 효과를 기대할 수 없다. 따라서, rifampicin에 내성인 돌연변이 균주를 얻기 위해 B. bifidum을 N-methyl-N'-nitro-N-nitroso- -guanidine(MNNG)로 처리하여 rifampicin에 내성인 30종의 균주를 선별 하였고, rifampicin에 대한 Minimal Inhibitory Concentration(MIC)를 측정해 본 결과 내성이 1,000배 이상 상승하였다. 또한 rifampicin에 내성인 균주 RFR61을 자연 돌연변이시켜 ofloxacin에도 내성인 돌연변이 균주 20종을 선별 하였고, MIC를 측정한 결과 내성이 4배 이상 증가하였다. 또, fructose-6-phosphate phosphoketolase test를 실시해 본 결과, 모두 Bifidobacterium임이 확인되었다. 유기산 생성량을 측정하여 모균주의 유기산 생성량과 가장 유사한 3균주, B. bifidum RFRll, RFR21, RFR61 그리고 OFR9을 선별하였다. 이 네 균주의 E. coli 생육 억제능을 측정한 결과 모두 모균주와 유사한 E. coli 생육 억제능을 가지고 있었다. Rifampicin 내성균주들에 대하여 내성 유지 시험을 한 결과 복귀 돌연변이에 의해 내성이 소실될 가능성은 없는 것으로 여겨진다. 마지막으로, 내성 균주에 의한 rifampicin 불활성화 여부를 알아 본 결과 rifampicin이 불활성 화되지 않음을 알 수 있었다. 이상의 결과를 통해 본 연구실에서 개발한 B. bifidum RFR11, RFR21 그리고 RFR61 균주들은 rifampicin에 내성이며, B.bifidum OFR9은 rifampicin과 ofloxacin에 이중 내성을 갖는 균주로서 모균주와 유사한 생화학적 특성을 갖는 우수한 정장 세균으로 여겨진다.

• Journal of Microbiology and Biotechnology
• /
• v.8 no.6
• /
• pp.581-587
• /
• 1998

Essential amino acids involved in the catalytic role of the extracellular cytosine deaminase from Chromobacterium violaceum YK 391 were determined by chemical modification studies. The enzyme activity required the reduced form of Fe (II) ion, since the enzyme was inhibited by ο-phenanthroline. The enzyme activity was completely inhibited by the chemical modifiers, such as p-chloromercuribenzoate (p-CMB), p-hydroxymercuribenzoate, and chloramine-T at 1 mM each. The enzyme activity was also markedly inhibited by pyridoxal-5'-phosphate, diethyl pyrocarbonate, and phenylmethylsulfonyl fluroride at 1 mM each. The inactivation of the enzyme activity with p-CMB was reversed by a high concentration of cytosine. Furthermore, the inactivation of the enzyme activity with p-CMB was also reactivated by 1 mM dithiothreitol, 1 mM 2-mercaptoethanol, 1 mM cysteine-HCI, 10% ethyl alcohol, and 10% methyl alcohol. These results suggested that cysteine and methionine residues might be located in or near the active site of the enzyme, while lysine, histidine, and serine residues might be indirectly involved in the enzyme activity.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.4
• /
• pp.248-254
• /
• 1992

The initial growth of Clostridium acetobutylicum was not inhibited by 1 atm of H$_2$ while H$_2$ reduced glucose consumption in a solventogenic culture of a phosphate limited 2-stage chemostat. Under 1 atm of H$_2$, a solventogenic culture consumed hydrogen, but an acidogenic culture produced hydrogen. H$_2$ consumption by the solventogenic culture was enhanced by the addition of 5 mM neutral red, an artificial electron carrier with a redox potential of -325 mV. Hydrogenase activity, measured in both directions of production and consumption, showed that activity coupled with methyl viologen is higher in an acidogenic culture than in a solventogenic culture, and that the two cultures have similar activities for methylene blue reduction. The solventogenic culture showed a higher activity coupled with neutral red than the acidogenic culture. From these results, it is hypothesized that hydrogen producing hydrogenase activity is high during the acidogenic phase, and decreases as solventogenesis starts, and that the solventogenic culture produces a second hydrogenase which uses an electron carrier other than ferredoxin. This hypothesis was supported by the fact that enzyme activities involved in electron flow can be coupled to neutral red, indepedent of ferredoxin, and that neutral red addition to the fermentation system increased butanol yield, with a decrease in production of less reduced fermentation products, and $H^2$.

• Microbiology and Biotechnology Letters
• /
• v.19 no.6
• /
• pp.614-618
• /
• 1991

Antifungal compound, KRF-001, was produced by Bacillus subtilis subsp. krictiensis isolated from soil. Physico-chemical factors affecting cell growth and bioactivity were examined to improve the production yield. Nutrient composition, temperature, pH and phosphate ion concentration were proved to be important factors for the production of KRF-001. Mutation was performed to select high yielding strains. First, mutation was performed with ultra-violet light, and the second mutation process was conducted by MNNG (N-Methyl-N'-nitro-N-nitrosoguanidine) resulting in three high yielding strains.

• Macromolecular Research
• /
• v.10 no.2
• /
• pp.122-126
• /
• 2002

A molecularly imprinted polymer (MIP) having both amidine and imidazole functional groups in the active site has been prepared using p-nitrophenyl phosphate as a transition state analogue (TSA). The imprinted polymer MIP with amidine and imidazole found to have the highest hydrolysis activity compared with other MIPs with either amidine or imidazole groups only. It is postulated a cooperative effect between amidine and imidazole in the hydrolysis of p-nitrophenyl methyl carbonate (NPMC) as a substrate when both groups were arranged in proximity by molecular imprinting. The rate enhancement of the hydrolysis by MIP was 60 folds over the uncatalyzed solution reaction and two folds compared with the control non-imprinted polymer CPI having both functional groups. The enzyme-mimetic catalytic hydrolysis of p-nitrophenyl acetate by MIP was evaluated in buffer at pH 7.0 with $K_{m}$ of 1.06 mM and $k_{cat}$ of 0.137 $h^{-1}$ . . .

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2012.05a
• /
• pp.20-20
• /
• 2012

Isoprenoids represent the most diverse group of metabolites, which are functionally and structurally identified in plant organism to date. Ginsenosides, glycosylated triterpenes, are considered to be the major pharmaceutically active ingredient of ginseng. Its backbones, categorized as protopanaxadiol (PPD), protopanaxatriol (PPT), and oleanane saponin, are synthesized via the isoprenoid pathway by cyclization of 2,3-oxidosqualene mediated with dammarenediol synthase or beta-amyrin synthase. The rate-limiting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), which is the first committed step enzyme catalyzes the cytoplasmic mevalonate (MVA) pathway for isoprenoid biosynthesis. DXP reductoisomerese (DXR), yields 2-C-methyl-D-erythritol 4-phosphate (MEP), is partly involved in isoprenoid biosynthesis via plastid. Squalene synthase and squalene epoxidase are involved right before the cyclization step. The triterpene backbone then undergoes various modifications, such as oxidation, substitution, and glycosylation. Here we will discuss general biosynthesis pathway for the production of ginsenoside and its modification based on their subcellular biological functions.

• YAKHAK HOEJI
• /
• v.35 no.1
• /
• pp.30-37
• /
• 1991

Streptomyces actuosus DMCJ-49 and Streptomyces minoensis DMCJ-144 produce the .alpha.-amylase inhibitor. Inerspecific protoplast fusion technique was used to increase the productivity of .alpha.-amylase inhibitor. Four auxotrophic mutants were obtained respectively from two strains by N-methyl-N'-nitor-N-nitrosoguanidine(3mg/ml) treatment. The optimum conditions for the protoplast formation of Streptomyces actuosus DMCJ-49 ade was as follows; 1.2% w/v of glycine, 3mg/ml of lysozyme, and 30 min of lysozyme treatment followed by 36 hr. incubation in the protop-last formation medium. In case of DMCJ-144-his those were 1.2%w/v, 3 mg/ml, 30 minutes and 60 hours, respectively. Regeneration was accomplished with hypertonic soft agar medium that contained 0.4M sucrose, 20mM CaCl$_2$, 50 mM MgCl$_2$ and low levels of phosphate. Fusion of protoplasts carrying different auxotrophic markers was achieved by treatment with polyethylene glycol. The optimum concentration of polyethylene glycol 1450 for the production of recombinants was 40%w/v. When the protoplasts was treated with 40% polyethylene glycol for 30 minutes, the frequency of recombinants was 6.5$\times$$10^{-3}$ and the $\alpha$-amylase inhibition activity of $ade^-his^-$ No. 4, which is the fusant with the most improved activity increased from 33 to 125 I.U./ml.

• YAKHAK HOEJI
• /
• v.43 no.3
• /
• pp.300-305
• /
• 1999

A sensitive and efficient assay method was applied to determine the level of glutamic acid (GA) and ${\gamma}-aminobutyric$ acid (GABA) in frontal cortex and hippocampus of rat administrated with ethanol and drugs. The compounds were derivatized with ο-phthalaldehyde (OPA) and 2-mercaptoethanof for precolunm analysis. The condition for the simultaneous determination of GA, GABA and $\beta-aminobutyric$ acid (BABA) by high performance liquid chromatography with electrochemical detection was reverse phase $C_{18}$ column as stationary phase, 0.1 M phosphate buffer containing 0.1 mM $Na_4EDTA$ : methanol = 55:45 (v+v) pH 3.8 as mobile phase and 0.7V electrode voltage. The stability of reaction product of GA, GABA and BABA with OPA could be increased by adding the same volume of polyethylene glycol 400 to reaction mixture. The GABA level in frotal cortex of rat was significantly decreased by the administration of picrotoxin and diazepam, but it was significantly increased by the administration of red ginseng total saponin, N-methyl-D-glucamine and (-)-deprenyl.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2003.05a
• /
• pp.17-17
• /
• 2003

tRNA (m¹ G37) methyltransferase (TrmD) catalyze s the trans for of a methyl group from S-adenosyl-L-methionine (AdoMet) to G/sup 37/ within a subset of bacterial tRNA species, which have a residue G at 36th position. The modified guanosine is adjacent to and 3' of the anticodon and is essential for the maintenance of the correct reading frame during translation. We have determined the first crystal structure of TrmD from Haemophilus influenzae, as a binary complex with either AdoMet or S-adenosyl-L-homocysteine (AdoHcy), as a ternary complex with AdoHcy/phosphate, and as an apo form. The structure indicates that TrmD functions as a dimer (Figure 1). It also suggests the binding mode of G/sup 36/G/sup 37/ in the active site of TrmD and catalytic mechanism. The N-terminal domain has a trefoil knot, in which AdoMet or AdoHcy is bound in a novel, bent conformation. The C-terminal domain shows a structural similarity to DNA binding domain of trp or tot repressor. We propose a plausible model for the TrmD₂-tRNA₂ complex, which provides insights into recognition of the general tRNA structure by TrmD (Figure 2).