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ABSTRACT: Four synthesized biocidal guanidine hydrochloride polymers with different alkyl chain length, including polyhexamethylene guanidine hydrochloride and its three new analogs, were used to investigate their interactions with phospholipids vesicles mimicking bacterial membrane. Characterization was conducted by using fluorescence dye leakage, isothermal titration calorimetry, and differential scanning calorimetry. The results showed that the gradually lengthened alkyl chain of the polymer increased the biocidal activity, accompanied with the increased dye leakage rate and the increased binding constant and energy change value of polymer-membrane interaction. The polymer-membrane interaction induced the change of pretransition and main phase transition (decreased temperature and increased width) of phospholipids vesicles, suggesting the conformational change in the phospholipids headgroups and disordering in the hydrophobic regions of lipid membranes. The above information revealed that the membrane disruption actions of guanidine hydrochloride polymers are the results of the polymer's strong binding to the phospholipids membrane and the subsequent perturbations of the polar headgroups and hydrophobic core region of the phospholipids membrane. The alkyl chain structure significantly affects the binding constant and energy change value of the polymer-membrane interactions and the perturbation extent of the phospholipids membrane, which lead to the different biocidal activity of the polymer analogs. This work provides important information about the membrane disruption action mechanism of biocidal guanidine hydrochloride polymers.
Acta Biochimica et Biophysica Sinica 09/2011; 43(9):729-37. · 1.38 Impact Factor
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ABSTRACT: Rice straw hydrolysate was used as lignocellulose-based carbon source for Chlorella pyrenoidosa cultivation and the feasibility of in situ biodiesel production was investigated. 13.7 g/L sugar was obtained by enzymatic hydrolyzation of rice straw. Chlorella pyrenoidosa showed a rapid growth in the rice straw hydrolysate medium, the maximum biomass concentration of 2.83 g/L was obtained in only 48 hours. The lipid content of the cells reached as high as 56.3%. In situ transesterification was performed for biodiesel production. The optimized condition was 1 g algal powder, 6 mL n-hexane, and 4 mL methanol with 0.5 M sulfuric acid at the temperature of 90°C in 2-hour reaction time, under which over 99% methyl ester content and about 95% biodiesel yield were obtained. The results suggested that the method has great potential in the production of biofuels with lignocellulose as an alternative carbon source for microalgae cultivation.
Journal of Biomedicine and Biotechnology 01/2011; 2011:141207. · 2.44 Impact Factor
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ABSTRACT: In this study, Scenedesmus obliquus SJTU-3 and Chlorella pyrenoidosa SJTU-2 were cultivated with 0.03%, 5%, 10%, 20%, 30%, 50% CO(2). The two microalgae could grow at 50% CO(2) (>0.69 g L(-1)) and grew well (>1.22 g L(-1)) under CO(2) concentrations ranging from 5% to 20%. Both of the two examined microalgae showed best growth potential at 10% CO(2). The maximum biomass concentration and CO(2) biofixation rate were 1.84 g L(-1) and 0.288 g L(-1) d(-1) for S. obliquus SJTU-3 and 1.55 g L(-1) and 0.260 g L(-1) d(-1) for C. pyrenoidosa SJTU-2, respectively. The main fatty acid compositions of the two examined microalgae were fatty acids with C(16)-C(18) (>94%) under different CO(2) levels. High CO(2) levels (30-50%) were favorable for the accumulation of total lipids and polyunsaturated fatty acids. The present results suggested that the two microalgae be appropriate for mitigating CO(2) in the flue gases and biodiesel production.
Bioresource technology 10/2010; 102(3):3071-6. · 4.25 Impact Factor
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ABSTRACT: A recombinant Zymomonas mobilis strain harboring the plasmid pHW20a-gfo for over-expression of glucose-fructose oxidoreductase (GFOR) was constructed. The specific activity of GFOR enzyme in the new recombinant strain was at least two folds greater than that in the wild strain. The maximum GFOR activity achieved in terms of the volumetric, and the cellular were 2.59 U ml(-1), and 0.70 U mg(-1), respectively, in the batch cultures. A significant improvement of the bioconversion process for the production of sorbitol and gluconic acid from glucose and fructose was made using divalent metal ions which drastically reduced the ethanol yield and significantly increased the yield of target product. Among several divalent metal ions evaluated, Zn(2+) was found to be most effective by inhibiting the Entner-Doudoroff pathway enzymes. The yield of the byproduct ethanol was reduced from 16.7 to 1.8 gl(-1) and the sorbitol yield was increased to almost 100% from 89%. The Ca(2+) enhanced the sorbitol yield and the formation of calcium gluconate salt made the separation of gluconate from the reaction system easier.
Journal of biotechnology 05/2010; 148(2-3):105-12. · 2.88 Impact Factor
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ABSTRACT: In order to establish the chemical biological technology for production of valuable secondary metabolites, a novel family of unnatural elicitors derived from the plant activator benzo-1,2,3-thiadiazole-7-carboxylic acid were designed and synthesized. New synthetic elicitors that showed powerful eliciting activities upon taxoid biosynthesis by Taxus chinensis suspension cells were obtained. For example, benzo-1,2,3-thiadiazole-7-carboxylic acid 2-(2-hydroxybenzoxyl)ethyl ester was more effective and resulted in nearly 40% increase in taxuyunnanine C content and production in comparison with methyl jasmonate, which was previously reported as the most powerful chemical elicitor for taxoid biosynthesis. The novel class of elicitors was found to induce plant defense responses, including promotion of H(2)O(2) levels originating from oxidative burst and activation of phenylalanine ammonia lyase. Interestingly the plant defense responses induced corresponded well to the superior stimulating activity in T. chinensis cell cultures. The work indicates that the newly synthesized benzothiadiazoles can act as a new family of elicitors for taxoid biosynthesis in plant cells.
Journal of Agricultural and Food Chemistry 12/2006; 54(23):8793-8. · 2.82 Impact Factor
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ABSTRACT: From the cultured cells of Panax notoginseng, a kind of ginseng saponin-ginsenoside Rg2, was separated and purified, and its structure was elucidated as 6-O-[alpha-L-rhamnose (l-->2)-beta-D-glucopyranosyl]3beta, 12beta, 20(S)-trihydroxydammar-24-ene [20(S)-ginsenoside Rg2]. Moreover, its bioactivity stimulates human umbilical cord vein endothelial cell proliferation; the growth of the cells treated with 20(S)-ginsenoside Rg2 was 14-fold higher than that of untreated ones, and the level of the cell's plasminogen activator (PA) was also twofold higher.
American Journal of Therapeutics 13(3):205-10. · 1.49 Impact Factor
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ABSTRACT: Ganoderma lucidum (GL) is known as a valuable herb in the search for anticancer lead compounds because it has been used for thousands of years as a traditional medication. Triterpenoids are the principal active components in this fungus. To examine the bioactivity of triterpene compounds, Ganoderic acid T (GA-T) was isolated from G. lucidum by high performance liquid chromatography (HPLC). In this study, we investigated the anti-invasion and antimetastasis mechanisms of GA-T in vitro. GA-T dose-dependently inhibited 95-D cells migration by wound healing assay. Results of cell aggregation and adhesion assay showed that GA-T could promote cell aggregation and simultaneously inhibit cell from adhering to extracellular matrix (ECM). In addition, GA-T suppressed MMP-2 and MMP-9 gene expression, hence, decreased protein level of MMP-2 and MMP-9 in 95-D cells, according to RT-PCR assay and Western blot assay. These results demonstrate that GA-T effectively inhibits tumor metastasis in vitro. According to the result of Western blot, the suppression of NF-κB activation likely abrogates the expression of MMP-2 and MMP-9, thus prevents tumor metastasis. These results suggest that GA-T has therapeutic potential against high metastatic lung carcinoma as a new agent.
Process Biochemistry.
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ABSTRACT: Ginseng saponins 20(S)-ginsenoside Rg2 extracted from cultured Panax notoginseng cells in a fermenter show a protection effect on human umbilical cord vein endothelial cells (VEC-304) from H2O2-induced cell apoptosis. When 50 μg/ml 20(S)-ginsenoside Rg2 was present in the culture medium for 8 h, the H2O2-damaged VEC-304 cells acquired about 11-fold (p < 0.01) on the amount and about 2-fold (p < 0.05) increase in PA activity compared with those untreated cells. And the Rg2 has a strong ability in scavenging intracellular ROS induced by H2O2.
Process Biochemistry.
