• Molecules and Cells
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• 제27권6호
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• pp.667-671
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• 2009

Visfatin (Nampt/PBEF) plays a pivotal role in the salvage pathway for $NAD^+$ biosynthesis. Its potent inhibitor, FK866, causes cellular $NAD^+$ levels to decline, thereby inducing apoptosis in tumor cells. In an effort to improve the solubility and binding interactions of FK866, we designed and synthesized IS001, in which a ribose group is attached to the FK866 pyridyl ring. Here, we report the crystal structure of rat visfatin in complex with IS001. Like FK866, IS001 is positioned at the dimer interface, and all of the residues that interact with IS001 are involved in hydrophobic or ${\pi}-{\pi}$-stacking interactions. However, we were unable to detect any strong interactions between the added ribose ring of IS001 and visfatin, which implies that a bulkier modifying group is necessary for a tight interaction. This study provides additional structure-based information needed to optimize the design of visfatin inhibitors.

• Nutritional Sciences
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• 제8권4호
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• pp.231-236
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• 2005

This study investigated the changes in the neuronal nitric oxide synthase (nNOS) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activities during food restriction in the rat brain such as cerebral cortex, cerebellum, caudate pautamen and hypothalamus. The rats were placed on a restricted feeding schedule consisting of half the ad libitum quantity for 3 days and 1, 2, 4, 6 and 9 weeks, and a free feeding schedule for 4 weeks. The loss of body weight peaked after 1 week of food restriction and persisted during the entire 9-week period of food restriction. The dramatic weight change in the first week ($12\%$) and the reduction in weight changes thereafter suggest that major adaptation changes occur early and body maintenance occurs subsequently. In the hypothalamus, the optical densities of the NADPH-d and nNOS immunoreactivities were found to be significantly higher in the 1-week and lower in the 9-week food restricted group than in the ad libitum fed control rats. In contrast, in the cerebral cortex, the optical densities of the NADPH-d- and nNOS-positive neurons were not changed significantly during the period of food restriction. This study provides the morphological evidence showing that food restriction has a significant effect on the nitric oxide synthesizing system of the hypothalamus.

• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.19-24
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• 1999

Plants have been shown to contains $Ca^{2+}$/calmodulin-stimulated GAD and NAD kinase. To test how calmodulin and calmodulin methylation affect the activation of GAD and NAD kinase, GAD and NAD kinase were partially purified from tobacco plants. GAD was also partially purified from E. coli transformed with a plasmid carrying a cloned tobacco GAD gene. We find that GAD from the transformed E. coli showed 60-fold $Ca^{2+}$/calmodulin-dependent activation. However, GAD from tobacco plants was stimulated only about 3.8-fold by the addition of calmodulin in the presence of calcium, suggesting high background activity of the enzyme was possibly due to bound endogenous tobacco calmodulin. There were no significant differences in the tobacco GAD activator properties between calmodulins. A monoclonal antibody against petunia GAD interacted strongly with both GAD from tobacco plants and GAD from cloned gene. NAD kinase from tobacco plants showed a complete $Ca^{2+}$/calmodulin dependency for activity. Unmethylated calmodulins activated GAD in a manner similar to methylated calmodulin. However, the maximum level of NAD kinase activation obtained with unmethylated calmodulins is approximately 4-fold higher than methylated calmodutins. These data suggested that endogenous tobacco calmodulin may interact more tightly with GAD than NAD kinase and that calmodulin methylation affects the activator properties of calmodulins for tobacco NAD kinase but not for GAD.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.1037-1043
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• 2020

Actinobacillus pleuropneumoniae (APP) is a causative agent of porcine pleuropneumonia. Therefore, the development of an effective vaccine for APP is necessary. Here, we optimized the culture medium and conditions to enhance the production yields of Apx toxins in APP serotype 1, 2, and 5 cultures. The use of Mycoplasma Broth Base (PPLO) medium improved both the quantity and quality of the harvested Apx toxins compared with Columbia Broth medium. Calcium chloride (CaCl₂) was first demonstrated as a stimulation factor for the production of Apx toxins in APP serotype 2 cultures. Cultivation of APP serotype 2 in PPLO medium supplemented with 10 ㎍/ml of nicotinamide adenine dinucleotide (NAD) and 20 mM CaCl₂ yielded the highest levels of Apx toxins. These findings suggest that the optimization of the culture medium and conditions increases the concentration of Apx toxins in the supernatants of APP serotype 1, 2, and 5 cultures and may be applied for the development of vaccines against APP infection.

• 한국자기공명학회논문지
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• 제9권1호
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• pp.29-37
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• 2005

Intra-cellular drug uptake in Xenopus laevis oocyte has been elucidated using localized MR spectroscopy (MRS) and PFG NMR techniques at a 600 $MH_z$(Bruker, 14.1 T) NMR spectrometer. The localized MRS has been done with a homemade probe, and shows the intra-cellular uptake of nicotinamide. The self-diffusion of the molecule in Xenopus oocyte was obtained by PFG NMR technique. The measured data are well fitted with a linear combination of two exponential functions, which shows that there are two types of drug molecules, intra-and extra-cellular molecules. Diffusion coefficients of intra- and extra-cellular drug molecules are 3.7 $\times$ $10^{-11}$ $\m^{2}/s$and 6.4 $\times$ $10^{-10}$ $\m^{2}/s$, respectively. In the weighting factors there is shown that about 5% of drug molecule is inside the cells. These techniques can be used for drug screening in molecule-, cell-, and tissue-based preclinical test.

• 대한수의학회지
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• 제48권3호
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• pp.243-250
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• 2008

A calmodulin-dihydrofolate reductase (DHFR) sandwich fusion protein was generated by insertion of calmodulin into the $\beta$-bulge region of DHFR to observe the effects of structurally constraining the calmodulin structure. The calcium binding properties of the sandwich protein were almost identical to calmodulin. Similar to calmodulin ($10.7 {\mu}M$), the sandwich protein bound four equivalents of calcium, with half saturation ($K_{0.5}$) observed at a [$Ca^{2+}$] of $8{\mu}M$. However, nicotinamide adenine dinucleotide (NAD) kinase activation property of the sandwich protein was lower than that of calmodulin. The sandwich protein activated NAD kinase, but to only half of the level obtained with calmodulin. The K 0.5 for both calmodulin and the sandwich protein were approximately the same (1-2 nM). Methylation analyses of the sandwich protein show that insertion of calmodulin into DHFR results in a large decrease in methylation. The $V_{max}$ observed with the sandwich protein (95 nmole/min/ml) was only 22% of the value observed with calmodulin (436 nmol/min/ml) in the presence of calcium. Addition of trimethoprim to the reaction significantly inhibited the observed methylation rate. Overall, the data suggest that the insertion of calmodulin into the DHFR structure has little effect on calcium binding by the individual lobes of calmodulin, but may constrain the lobes in a manner that results in altered interaction with the calmodulin-dependent proteins, and severely perturbed the methyltransferase recognition site.

• Tuberculosis and Respiratory Diseases
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• 제57권2호
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• pp.180-182
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• 2004

항결핵제중 isoniazid는 nicotinic acid의 합성을 방해하여 pellagra의 발생을 초래할 수 있다. 저자들은 70세 여자 환자에서 폐결핵 치료중 isoniazid에 의해 발생한 pellagra 1례를 경험하였기에 문헌고찰과 함께 보고하는 바이다.

• 한국식품영양과학회지
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• 제27권3호
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• pp.425-432
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• 1998

The strain producing L-lactic acid from starch was isolated from kimchi. The isolated strain was identified as a homofermentative Streptococcus sp. through its morphological, cultural, biochemical characteristics, and named Streptococcus sp. JEJ-6. Lactic acids are of two types, one L-specific and the other D-specific form in a stereospecific form. Streptococcus sp. JEJ-6 produced selectively L-lactic acid from all of the tested carbon sources. The optimum conditions for the L-lactic acid production from the isolated microorganism were determined. For the maximum yield of L-lactic acid from Streptococcus sp. JEJ-6, the cell should be harvested at the early stationary phase, and the growth temperature, pH, and NaCl concentration should be 37$^{\circ}C$, pH 7.0 and 0.1%, respectively. 4% Soluble starch as substrate and organic nitrogen sources such as peptone and yeast extract should be used for the best yield. The optimum pH of the nicotinamide adenine dinucleotide(NAD)-dependent and NAD-independent lactate dehydrogenase(LDH) activities was pH 8.5 and pH 7.0, respectively.

• 대한의생명과학회지
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• 제12권3호
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• pp.233-240
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• 2006

We investigated enzyme activity and histochemical changes in hind limb of mouse treated with 6-aminonicotinamide (6-AN). The activity of aspartate aminotransferase, alanine aminotransferase and creatine phosphokinase in 6-AN treated group were significantly higher than those of the control and pair-fed groups. Also, the activity of lactic dehydrogenase in 6-AN treated group was the highest among the three groups, whereas that of the pair-fed group were higher than that of the control group. In the 6-AN treated group, oxidative histochemical stains, nicotinamide adenine dinucleotide reductase (NADH), succinyl dehydrogenase (SDH) showed increased scattered fibers in 6-AN treated subsarcolemma. Cytochrome c oxidase (COX) stain showed decreased up to 85% in 6-AN treated fibers. These results demonstrate that 6-AN antagonizes cell metabolism and induces the morphological deformity like the other mitochondrial muscle diseases. Therefore, we suppose that these data would be useful indexes for disclosing the mechanism of mitochondrial muscle disease.

• BMB Reports
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• 제28권1호
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• pp.79-82
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• 1995

Exposure of spleen lymphocytes to 2-chloroethylethyl sulfide (CEES) leads to a reduction of the intracellular ATP level, followed by a decrease in cell viability. Addition of nicotinamide, an inhibitor of poly(ADP-ribose) polymerase (PADPRP), restores both ATP level and viability, indicating that an activation of PADPRP is responsible for the cytotoxicity of CEES. The involvement of a $Ca^{2+}$-mediated process in cytotoxicity is suggested. Verapamil, EGTA, trifluoperazine, and butacaine exhibit a partial protection (20 to 58%) against the cytotoxicity of CEES. Investigation of the causative role of proteolytic degradation in cell death indicate that pepstatin and leupeptin exert a substantial protective effect (60 to 70%), suggesting the involvement of lysosomal destabilization in CEES-induced cytotoxicity. Also, lysosomotropic agents markedly decrease the cytotoxicity. Lysosomal labilization may be a mechanism for the cytotoxicity of CEES.