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1.
A thermostable chitosanase gene from the environmental isolate Bacillus sp. strain CK4, which was identified on the basis of phylogenetic analysis of the 16S rRNA gene sequence and phenotypic analysis, was cloned, and its complete DNA sequence was determined. The thermostable chitosanase gene was composed of an 822-bp open reading frame which encodes a protein of 242 amino acids and a signal peptide corresponding to a 30-kDa enzyme. The deduced amino acid sequence of the chitosanase from Bacillus sp. strain CK4 exhibits 76.6, 15.3, and 14.2% similarities to those from Bacillus subtilis, Bacillus ehemensis, and Bacillus circulans, respectively. C-terminal homology analysis shows that Bacillus sp. strain CK4 belongs to cluster III with B. subtilis. The gene was similar in size to that of the mesophile B. subtilis but showed a higher preference for codons ending in G or C. The enzyme contains 2 additional cysteine residues at positions 49 and 211. The recombinant chitosanase has been purified to homogeneity by using only two steps with column chromatography. The half-life of the enzyme was 90 min at 80°C, which indicates its usefulness for industrial applications. The enzyme had a useful reactivity and a high specific activity for producing functional oligosaccharides as well, with trimers through hexamers as the major products.  相似文献
2.
The effect of tea polyphenol (TP) on cognitive and anti-cholinesterase activity was examined in scopolamine-treated mice. Chronic administration of TP significantly reversed scopolamine-induced retention deficits in both step-through passive avoidance and spontaneous alternation behavior tasks. Furthermore, TP exhibited a dramatic inhibitory effect on acetylcholinesterase activity. This finding suggests that TP might be useful in the treatment of Alzheimer's disease.  相似文献
3.
Protective effects of Platycodi radix on alcohol-induced fatty liver   总被引:4,自引:0,他引:4  
The protective effects of Platycodi radix (PR), the root of Platycodon grandiflorum A. DC, on alcohol-induced fatty liver and possible mechanisms involved in this protection were investigated in rats. Administration of PR significantly prevented alcohol-induced elevation of serum and liver lipids. Furthermore, PR treatment normalized hepatic liver fatty acid binding protein (L-FABP) expression and cytochrome P450 2E1 (CYP2E1) activity in alcohol-treated rats. These results suggest that inhibition of CYP2E1 and regulation of L-FABP by PR play an important role in alcohol-induced hepatoprotection.  相似文献
4.
Effects of oleamide on choline acetyltransferase and cognitive activities   总被引:2,自引:0,他引:2  
We screened 50 Korean traditional natural plants to measure the activation effect on choline acetyltransferase and attenuation of scopolamine-induced amnesia. The methanolic extracts from Zizyphus jujuba among the tested 50 plants, showed the highest activatory effect (34.1%) on choline acetyltransferase in vitro. By sequential fractionation of Zizyphus jujuba, the active component was finally identified as cis-9-octadecenoamide (oleamide). After isolation, oleamide showed a 65% activation effect. Administration of oleamide (0.32%) to mice significantly reversed the scopolamine-induced memory and/or cognitive impairment in the passive avoidance test and Y-maze test. Injection of scopolamine to mice impaired performance on the passive avoidance test (31% decrease in step-through latency), and on the Y-maze test (16% decrease in alternation behavior). In contrast, mice treated with oleamide before scopolamine injection were protected from these changes (12-25% decrease in step-through latency; 1-10% decrease in alternation behavior). These results suggest that oleamide should be a useful chemo-preventive agent against Alzheimer's disease.  相似文献
5.
Kim DS  Woo ER  Chae SW  Ha KC  Lee GH  Hong ST  Kwon DY  Kim MS  Jung YK  Kim HM  Kim HK  Kim HR  Chae HJ 《Life sciences》2007,80(4):314-323
Plantainoside D (PD), was isolated from the leaves of Picrorhiza scrophulariiflora (Scrophulariaceae). The anti-oxidative activity of PD was evaluated based on scavenging effects on hydroxyl radicals and superoxide anion radicals. Adriamycin (ADR) is a potent anti-tumor drug known to cause severe cardiotoxicity. Although ADR generates free radicals, the role of free radicals in the development of cardiac toxicity has not been understood. This study was undertaken to investigate the protective effect of PD against ADR-induced apoptosis. In vitro, ADR caused dose-dependent toxicity in H9c2 cardiac muscle cells. Pre-treatment of the cardiac muscle cells with PD significantly reduced ADR-induced apoptosis of cardiac muscle cells. PD inhibited the ROS produced by ADR in the cardiac muscle cells. As well, PD increased GSH(glutathione), compared with ADR. In response to ADR, NF-kappaB was activated in H9c2 cells. However the treatment of PD reduced the activation of NF-kappaB. We also observed that the NF-kappaB inhibitor, PDTC, inhibited the cytotoxic effect on ADR-induced apoptosis in cardiac muscle cells. In parallel, IkappaBalpha-dominant negative plasmid-overexpression abrogated ADR-induced apoptosis in H9c2 cardiac muscle cells. In conclusion, these results suggest that Plantaionoside D can inhibit ADR-induced apoptosis in H9C2 cardiac muscle cells via inhibition of ROS generation and NF-kappaB activation. The pure compound PD can be a potential candidate agent which protects cardiotoxicity in ADR-exposed patients.  相似文献
6.
Kim JH  Yang SH  Yu MY  Lee HK  Kim SY  Kim SH 《Regulatory peptides》2004,120(1-3):93-98
Dendroaspis natriuretic peptide (DNP), a 38-amino-acid peptide, was isolated from the venom of Green Mamba. It has structural and functional similarities to other members of the natriuretic peptide family. The purpose of this study was to determine whether DNP system is present in the rat colon and to define its biological functions. The serial dilution curve of extracts of colonic tissues was parallel to the standard curve of DNP and a major peak of molecular profile by HPLC was synthetic DNP. The concentration of DNP was 0.5±0.04 ng/g of colonic tissues. DNP as well as atrial natriuretic peptide and C-type natriuretic peptide caused dose-dependent increases in cGMP production in the purified membrane of colonic tissues. Three types of natriuretic peptide receptor mRNAs were detected using semi-quantitative RT-PCR. Functionally, synthetic DNP inhibited the spontaneous contraction of rat colonic circular muscle in a concentration-dependent manner. The potency appeared to be at least 10 times greater than that of CNP. Furthermore, DNP inhibited carbachol-induced muscle contraction, suggesting that it also can modulate the nerve regulation of colonic motility. This study demonstrates the presence of DNP system in rat colon and its function as a local regulator of colonic motility.  相似文献
7.
Acetylcholinesterase (AChE) inhibitors, which enhance cholinergic transmission by reducing the enzymatic degradation of acetylcholine, are the only source of the compound that is currently approved for the treatment of Alzheimer's disease (AD). The methanol extract from Fiatoua villosa among 100 traditional edible plants that were tested, showed the most potent inhibitory effect (51%) on acetylcholinesterase in vitro. After the sequential solvent fractionation of the methanol extract of Fiatoua villosa, the active fraction was repeatedly subjected to open-column chromatography on silica gel. From the highest inhibitory fraction, the chloroform fraction (75%) on AChE, the single compound, was obtained by the Sep-Pak Cartridge (C18: reverse phase column). This compound was finally purified by HPLC (micro-bondapack C18 reverse phase column: 19 x 300 mm). According to the electron impact mass spectrometry (EI-MS), we confirmed that the molecular mass was 219 m/z. The structure of this compound was identified as zeatin [2-methyl-4-(1H-purine-6-ylamino)-2-buten-1-ol], one of the derivatives of purine adenine. The concentration that was required for 50% enzyme inhibition (IC50 value) was 1.09 x 10(-4) M. This study demonstrated that the zeatin from Fiatoua villosa appeared to be the most potent AChE inhibitor in AD.  相似文献
8.
The anti-diabetic and antioxidative effect of amaranth grain (AG) and its oil fraction (AO) was studied in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into four groups after induction of STZ-diabetes: normal control; diabetic control; diabetic-AG supplement (500 g kg(-1) diet); diabetic-AO supplement (100 g kg(-1) diet) and fed experimental diets for 3 weeks. Serum glucose, insulin, activities of serum marker enzymes of liver function and liver cytosolic antioxidant enzymes were measured. The AG and AO supplement significantly decreased the serum glucose and increased serum insulin level in diabetic rats. Serum concentration of liver function marker enzymes, GOT and GPT, were also normalized by AG and AO treatment in diabetic rats. Liver cytosolic SOD and GSH-reductase activities were significantly increased, and catalase, peroxidase and GSH-Px activities were decreased in diabetic rats. AG and AO supplement reverted the antioxidant enzyme activities to near normal values. Hepatic lipid peroxide product was significantly higher, and GSH content was decreased in diabetic rats. However, AG and AO supplement normalized these values. Our data suggest that AG and AO supplement, as an antioxidant therapy, may be beneficial for correcting hyperglycaemia and preventing diabetic complications.  相似文献
9.
The choline acetyltransferase (ChAT) activator, which enhances cholinergic transmission via an augmentation of the enzymatic production of acetylcholine (ACh), is an important factor in the treatment of Alzheimer's disease (AD). Methanolic extracts from Pueraria thunbergiana exhibited an activation effect (46%) on ChAT in vitro. Via the sequential isolation of Pueraria thunbergiana, the active component was ultimately identified as daidzein (4',7-dihydroxy-isoflavone). In order to investigate the effects of daidzein from Pueraria thunbergiana on scopolamine-induced impairments of learning and memory, we conducted a series of in vivo tests. Administration of daidzein (4.5 mg/kg body weight) to mice was shown significantly to reverse scopolamine-induced amnesia, according to the results of a Y-maze test. Injections of scopolamine into mice resulted in impaired performance on Y-maze tests (a 37% decreases in alternation behavior). By way of contrast, mice treated with daidzein prior to the scopolamine injections were noticeably protected from this performance impairment (an approximately 12%-21% decrease in alternation behavior). These results indicate that daidzein might play a role in acetylcholine biosynthesis as a ChAT activator, and that it also ameliorates scopolamine-induced amnesia.  相似文献
10.
Endogenous antioxidant defense systems are enhanced by various physiological stimuli including sublethal oxidative challenges, which induce tolerance to subsequent lethal oxidative injuries. We sought to evaluate the contributions of catalase and the glutathione system to the adaptive tolerance to H2O2. For this purpose, H9c2 cells were stimulated with 100 microM H2O2, which was the maximal dose at which no significant acute cell damage was observed. Twenty-four hours after stimulation, control and pretreated cells were challenged with a lethal concentration of H2O2 (300 microM). Compared with the control cells, pretreated cells were significantly tolerant of H2O2, with reduced cell lysis and improved survival rate. In pretreated cells, glutathione content increased to 48.20 +/- 6.38 nmol/mg protein versus 27.59 +/- 2.55 nmol/mg protein in control cells, and catalase activity also increased to 30.82 +/- 2.64 versus 15.46 +/- 1.29 units/mg protein in control cells, whereas glutathione peroxidase activity was not affected. Increased glutathione content was attributed to increased gamma-glutamylcysteine synthetase activity, which is known as the rate-limiting enzyme of glutathione synthesis. To elucidate the relative contribution of the glutathione system and catalase to tolerance of H2O2, control and pretreated cells were incubated with specific inhibitors of gamma-glutamyl cysteine synthetase (L-buthionine sulfoximine) or catalase (3-amino-1,2,4-triazole), and challenged with H2O2. Cytoprotection by the low-dose H2O2 pretreatment was almost completely abolished by L-buthionine sulfoximine, while it was preserved after 3-amino-1,2,4-triazole treatment. From these results, it is concluded that both the glutathione system and catalase can be enhanced by H2O2 stimulation, but increased glutathione content rather than catalase activity was operative in the tolerance of lethal oxidative stress.  相似文献
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