4.Effect of Phosphorylation on Peptidyl-Prolyl Imide Bond cis/trans Isomerization of Peptides With Xaa-Pro Motif
Zhentai ZHU ; Ming SUN ; Yanting GUO ; Yanmei LI
Progress in Biochemistry and Biophysics 2007;34(6):585-594
The peptidyl-prolyl imide bond cis/trans isomerization of Xaa-Pro motif in the peptide and protein plays an important role to influence their conformation and function. Here, a series of model peptides including phosphorylated and its unphosphorylated counterparts were designed and synthesized. Preliminary 1H NMR experiments and molecular dynamics (MD) simulation were used to analyze the peptidyl-prolyl cis/trans imide bond isomerization. The data indicated that the side-chain O-phosphorylation of the Xaa residues preceding proline affected evidently the isomerization and thereby regulated the peptides conformations. The charges of the phosphate moiety as well as their steric effects might be the driving force for the conformational changes of these phosphopeptides.Moreover, the obtained most stable multiple configurations and their statistic cis/trans concentration distribution in MD simulation were basically consistent with the NMR experiments, which demonstrated that phosphorylation increased the cis conformation of the peptide and the maximum cis ratio is given while the phosphate group has no negative charge.
7.Progress on Biotechnological Production of Butyric Acid
Ming-Rong DENG ; Jun GUO ; Hong-Hui ZHU ;
China Biotechnology 2006;0(03):-
Butyric acid can be used to produce cellulose butyrate fiber and ester derivatives,and to be applied in foodstuffs and perfume industries.Recent researches have found that butyric acid is a preferred carbon source for colonic epithelial cells,and can inhibit histone deacetylase,showing great anticancer potentials.With more and more functions of butyric acid being found and applied in bio-related fields,and with consumer's growing preference to bioproducts,biotechnological production of butyric acid will receive more competence than petroleum-based chemical synthesis.Low product concentration and poor selectivity are presently the main restricting factors.Workers have made considerable progress on more cheep carbon sources,optimization of fermentation process,simplifying downstream processing,and genetic engineering of producing strains.Any achievement on these aspects in the future can contribute to put fermentation of butyric acid into industry.
8.Purification and Characterization of Laccase from Monodictys asperospera (Cooke & Massee) Ellis
Yi-Ning WANG ; Guo-Zhu ZHAO ; Yue-Ming ZHAO ; Xiao-Liang DI ; Xiang-Ming XIE ;
Microbiology 2008;0(11):-
A new wood-degrading fungus Monodictys asperospera(Cooke & Massee) Ellis with a high level of laccase production was chosen to study.This laccase was purified by ammonium sulfate precipitation,DEAE-cellulose and sephacryl S-300.Purification of about 8.1 fold was achieved with an overall yield of 5.7%.Its molecular weight was estimated to be about 77 kD.The optimum temperature and pH of the lac-case activity were 55?C and 6.0,respectively.Kinetic studies of the laccase showed that the Km and the Vmax for using syringaldazine as substrate was 0.163 mmol/L and 0.194 mmol/(L.min),respectively.The carbo-hydrate content was 18.14%.In addition,it was found that laccase activity was significantly inhibited by Cu2+.
9.Microsurgery for sellar region lesions via frontolateral approach
Bao-Guo LIU ; Li-Ming HE ; Gang XIAO ; Ming GUO ; Biao ZHU
Chinese Journal of Neuromedicine 2012;11(6):633-635
Objective To investigate the feasibility and effect of frontolateral approach in microsurgical treatment of sellar region lesions. Methods Twenty-eighty patients with sellar region lesions,admitted to our hospital from January 2009 to December 2011,were treated with microsurgery via frontolateral approach; a retrospective analysis of their clinical data was conducted. In these 28 patients,8 had meningiomas ofsellar tuberculum and anterior clinoidal process,5 pituitary tumors,3 craniopharyngiomas, 1 cholesteatoma, 6 anterior communicafing artery aneurysms and 5 posterior communicating artery aneurysms. Results The total removal was achieved in 12 of the 17 patients with sellar region tumors,and subtotal removal in 5.Six patients with anterior communicating artery aneurysm and 5 with posterior communicating artery aneurysm were successfully clipped.No death or severely disabled case were noted. Conclusion The microsurgery via frontolateral approach can fully expose the sellar region lesions and proper treatment can be given, which is minimally invasive and enjoys satisfactory result.
10.Chili arsenic contamination in southwest China and its influencing factors
Ming-guo, WANG ; She-hong, LI ; Bo, LI ; Jian-ming, ZHU ; Tang-fu, XIAO ; Bao-shan, ZHENG
Chinese Journal of Endemiology 2010;29(6):645-648
Objective To determine the distribution and influencing factors(dehydration method, storage time and chili varieties) of arsenic contents in chilies from southwest China, and the relationship between arsenic content and selenium content in chilies. Methods There were 272 dried chili samples, 76 groups of fresh chili samples and its corresponding soil samples, which were collected from the markets and peasant households in 76 counties of 9 regions in southwest China, and 36 dried chilies from other regions in China and abroad as a comparison. Their dehydration methods and storage time were investigated. The chilies were classified by Bailey Criteria. Arsenic content and selenium content in chilies were determined with hydride generation atomic fluorescence spectrometry. Arsenic content in soils were determined with water bath hydride generation atomic fluorescence spectrum. Results Their ranges of arsenic content in dried chili and fresh chili were 0.2 - 16 637.3,0.2 - 295.8 μg/kg, respectively. The median of arsenic content in the dried chili was 106.9 μg/kg while it was 0.2 μg/kg (dry weight) in the fresh chili. The chilies median arsenic of different drying methods and storage time, in order were: the furnace-dried stored for more 1 than year( 197.3 μg/kg), the sun-dried stored for more than 1 year (130.7 μg/kg), the furnace-dried stored for less than 1 year(94.1 μg/kg), the sun-dried stored for less than 1 year (55.5 μg/kg). The arsenic content of different kinds of solar-dried chilies and roast chilies were different. In solar-dried chilies, the median of arsenic contents from a order of high to low sequences were cluster chili (101.5 μg/kg), cherry chili (95.6 μg/kg), corn chili (86.8 μg/kg), and long chili (47. 1 μg/kg); in roast chilies, the median of arsenic contents from a order of high to low sequences were cherry chili(275.5 μg/kg), cluster chili (173.0 μg/kg), corn chili( 164.3 μg/kg), and long chili( 136.8 μg/kg). The medians of chilies from other regions of China and Turkey were higher than that of southwest China, their median were 125.8,112.3 μg/kg, respectively;the medians of chilies from America, France, and other countries were lower than that of southwest China, their median were 29.4,54.1,85.3 μg/kg, respectively. There was no significant correlation between fresh chilies and its corresponding soil arsenic(r = 0.010, P > 0.05). There was a significant positive correlation between the amount of arsenic and selenium in chilies(r = 0.616, P < 0.05). Conclusions The arsenic of dried chilies from southwest China was higher than that of fresh chilies. The arsenic of chili was different with different dehydration methods and storage time. There was a significant positive correlation between the amount of arsenic and selenium in chilies.