|
Identification of Rhodiola species by using RP-HPLC*
WANG Qiang, RUAN Xiao, JIN Zhi-hua, YAN Qi-chuan, TU Shanjun
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2005, 6(6): 6-.
https://doi.org/10.1631/jzus.2005.B0477
An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to identify ten species of Rhodiola, R. coccinea A. Bor, R. junggarica C.Y. Yang et N.R. Cui spn., R. heterodonta A. Bor, R. linearifolia A. Bor, R
|
|
Optimization of angiotensin I-converting enzyme (ACE) inhibition by rice dregs hydrolysates using response surface methodology
HE Guo-qing, XUAN Guo-dong, RUAN Hui, CHEN Qi-he, XU Ying
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2005, 6(6): 11-.
https://doi.org/10.1631/jzus.2005.B0508
Angiotensin I-converting enzyme (ACE) inhibitory peptides have been shown to have antihypertensive effects and have been utilized for physiologically functional foods and pharmaceuticals. The ACE inhibitory ability of a hydrolysate is determined by its peptide composition. However, the peptide composition of a hydrolysate depends on proteolytic enzyme and the hydrolysis conditions. In this study, the effect of process conditions on the ACE inhibitory activity of rice dregs hydrolyzed with a trypsin was investigated systematically using response surface methodology. It was shown that the ACE inhibitory activity of rice dregs hydrolysates could be controlled by regulation of five process conditions. Hydrolysis conditions for optimal ACE inhibition were defined using the response surface model of fractional factorial design (FFD), steepest ascent design, and central composite design (CCD).
|
|
Study on US/O3 mechanism in p-chlorophenol decomposition
XU Xian-wen, XU Xin-hua, SHI Hui-xiang, WANG Da-hui
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2005, 6(6): 19-.
https://doi.org/10.1631/jzus.2005.B0553
Study on the effects of sonolysis, ozonolysis and US/O3 system on the decomposition of p-chlorophenol in aqueous solutions indicated that in the cases of US/O3 system, individual ozonolysis and sonolysis, the decomposition rate of p-chlorophenol reached 78.78%, 56.20%, 2.79% after a 16-min reaction while its CODcr (chemical oxygen demand) removal rate was 97.02%, 62.17%, 3.67% after a 120-min reaction. The decomposition reaction of p-chlorophenol follows pseudo-first-order kinetics. The enhancement factors of p-chlorophenol and its CODcr under US/O3 system reached 63% and 237% respectively. The main intermediates during the decomposition include catechol, hydroquinone, p-benzoquinone, phenol, fumaric acid, maleic acid, oxalic acid and formic acid. The decomposition mechanism of p-chlorophenol was also discussed.
|
|
Study on anaerobic treatment of wastewater containing hexavalent chromium*
XU Yan-bin, XIAO Hua-hua, SUN Shui-yu
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2005, 6(6): 23-.
https://doi.org/10.1631/jzus.2005.B0574
A self-made anaerobic bio-filter bed which was inoculated with special sludge showed high efficiency in removing hexavalent chromium. When pump flow was 47 ml/min and CODCr of wastewater was about 140 mg/L, it took 4 h to decrease the Cr6+ concentrations from about 60 mg/L to under 0.5 mg/L, compared with 14 h without carbon source addition. Cr6+ concentrations ranged from 64.66 mg/L to 75.53 mg/L, the system efficiency was excellent. When Cr6+ concentration reached 95.47 mg/L, the treatment time was prolonged to 7.5 h. Compared with the contrast system, the system with trace metals showed clear superiority in that the Cr6+ removal rate increased by 21.26%. Some analyses also showed that hexavalent chromium could probably be bio-reduced to trivalent chromium, and that as a result, the chrome hydroxide sediment was formed on the surface of microorganisms.
|
|
Preparation, crystallization and preliminary X-ray diffraction analysis of PH1948, predicted RNA methyltransferase from Pyrococcus horikoshii
GAO Yong-gui, YAO Min, TANAKA Isao
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2005, 6(6): 454-456.
https://doi.org/10.1631/jzus.2005.B0454
RNA methyltransferase is responsible for transferring methyl and resulting in methylation on the bases or ribose ring of RNA, which existed widely but mostly remains an open question. A recombinant protein PH1948 predicting RNA methyltransferase from Pyrococcus horikoshii OT3 has been crystallized. The crystals of selenomethionyl PH1948 belong to space group C2, with unit-cell parameters a=207.0 Å, b=43.1 Å, c=118.2 Å, β=92.1°, and diffract X-rays to 2.2 Å resolution. The VM value was determined to be 2.8 Å3/Da, indicating the presence of four protein molecules in the asymmetric unit.
|
|
Pathogenicity of bacterium, Xenorhabdus nematophila isolated from entomopathogenic nematode (Steinernema carpocapsae) and its secretion against Galleria mellonella larvae
MAHAR Ali Nawaz, MUNIR Muhammad, ELAWAD Sami, GOWEN Simon Richard, HAGUE Nigel Graham Meckenzi
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2005, 6(6): 457-463.
https://doi.org/10.1631/jzus.2005.B0457
The entomopathogenic bacterium, Xenorhabdus nematophila was isolated from the hemolymph of Galleria mellonella infected with Steinernema carpocapsae. The bacterial cells and its metabolic secretions have been found lethal to the Galleria larvae. Toxic secretion in broth caused 95% mortality within 4 d of application whereas the bacterial cells caused 93% mortality after 6 d. When filter and sand substrates were compared, the later one was observed as appropriate. Similarly, bacterial cells and secretion in broth were more effective at 14% moisture and 25 °C temperature treatments. Maximum insect mortality (100%) was observed when bacterial concentration of 4×106 cells/ml was used. Similarly, maximum bacterial cells in broth (95%) were penetrated into the insect body within 2 h of their application. However, when stored bacterial toxic secretion was applied to the insects its efficacy declined. On the other hand, when the same toxic secretion was dried and then dissolved either in broth or water was proved to be effective. The present study showed that the bacterium, X. nematophila or its toxic secretion can be used as an important component of integrated pest management against Galleria.
|
29 articles
|