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81.
82.
How RNA sequences fold to specific tertiary structures is one of the key problems for understanding their dynamics and functions. Here, we study the folding process of an H-type RNA pseudoknot by performing a large-scale all-atom MD simulation and bias-exchange metadynamics. The folding free energy landscapes are obtained and several folding intermediates are identified. It is suggested that the folding occurs via multiple mechanisms, including a step-wise mechanism starting either from the first helix or the second, and a cooperative mechanism with both helices forming simultaneously. Despite of the multiple mechanism nature, the ensemble folding kinetics estimated from a Markov state model is single-exponential. It is also found that the correlation between folding and binding of metal ions is significant, and the bound ions mediate long-range interactions in the intermediate structures. Non-native interactions are found to be dominant in the unfolded state and also present in some intermediates, possibly hinder the folding process of the RNA. 相似文献
83.
Zheng Ma Jinxiu Liu Xiaozhen Lin Xuping Shentu Yalin Bian Xiaoping Yu 《Folia microbiologica》2014,59(2):93-97
Toyocamycin exhibits effective biological activities for use against plant pathogenic fungi thanks to its structural similarity to nucleoside. It has been recognized as a promising agricultural antibiotic utilized in controlling the occurrence of plant diseases. In our previous study, a strain that was isolated was identified and designated as Streptomyces diastatochromogenes whose major secondary metabolite was toyocamycin, but the production was largely limited. Protoplast transformation is a useful technique in the improvement of streptomycete. In this study, we optimized some key factors necessary for protoplast formation, regeneration, and transformation of S. diastatochromogenes. When mycelium was cultivated in CP medium with 1 % glycine, harvested at 48 h old, and then treated with 3 mg lysozyme/mL in P buffer for 1 h, the greatest regeneration frequency (42.5 %) of protoplasts was obtained. By using 1?×?109/mL protoplasts with polyethylene glycol 1000 at a concentration of 30 % (w/v), the best performance of protoplast transformation efficiency was 4.8?×?103/μg DNA transformants. 相似文献
84.
85.
Design and selection of trap color for capture of the tea leafhopper,Empoasca vitis,by orthogonal optimization 总被引:2,自引:0,他引:2
Lei Bian Xiao‐Ling Sun Zong‐Xiu Luo Zheng‐Qun Zhang Zong‐Mao Chen 《Entomologia Experimentalis et Applicata》2014,151(3):247-258
The tea leafhopper, Empoasca vitis (Göthe) (Hemiptera: Cicadellidae), is a major pest of the tea plant, Camellia sinensis (L.) O. Kuntze (Theaceae). In this study, the RGB color model was used to describe the colors of sticky traps. The most effective color for attraction of E. vitis was investigated by orthogonal optimization. The selected color was verified in tea gardens and the most effective height for positioning of color sticky traps for capturing tea leafhoppers was investigated. After the determination of the effect of the three color parameters and their interactions by orthogonal optimization, the color gold (RGB: 255, 215, 0) was selected as the most effective color to trap tea leafhoppers. In tea gardens, more leafhoppers were captured using gold sticky traps (RGB: 226, 204, 4) than using commercially available yellow sticky traps. The most effective height of gold sticky traps for trapping leafhoppers was 40–60 cm above the tea canopy. Few lady beetles were captured at this height. We conclude that the orthogonal optimization method is a convenient and efficient method to screen digitally generated colors for attracting and trapping of pests. 相似文献
86.
Xiaoliang Liang Yan Bian Xiao-Feng Tang Gengfu Xiao Bing Tang 《Applied microbiology and biotechnology》2010,87(3):999-1006
WF146 protease, a thermophilic subtilase from thermophile Bacillus sp. WF146, suffers excessive autolysis in the presence of reducing agents. In this report, two autolytic sites of WF146 protease
were modified by site-directed mutagenesis. The introduction of prolines into the autolytic sites increased the autolysis
resistance of the enzyme under reducing conditions. The double mutant N63P/A66P displayed a 2.8-fold longer half-life at 80°C
and higher hydrolytic activities than wild-type enzyme toward soluble (casein) and insoluble (keratin azure) substrates at
high temperatures. In the presence of reducing agents, N63P/A66P was able to degrade feather at 80°C (∼3 h), with hydrolysis
efficiency comparable to that of proteinase K at 50°C (∼24 h). Meanwhile, the mutant N63P/A66P had the ability to hydrolyze
PrPSc-like prion protein at high temperatures. In virtue of these properties, N63P/A66P is of great interest to be used in recycling
of keratinous wastes, such as feather, and disinfection of medical apparatus. In addition, our study may provide useful information
needed to explore keratinolytic potential of thermophilic subtilases, even if they are produced by non-keratinolytic microorganisms. 相似文献
87.
Genome-wide analysis of primary auxin-responsive Aux/IAA gene family in maize (Zea mays. L.) 总被引:1,自引:0,他引:1
Yijun Wang Dexiang Deng Yunlong Bian Yanping Lv Qin Xie 《Molecular biology reports》2010,37(8):3991-4001
The phytohormone auxin is important in various aspects of organism growth and development. Aux/IAA genes encoding short-lived nuclear proteins are responsive primarily to auxin induction. Despite their physiological importance, systematic analysis of Aux/IAA genes in maize have not yet been reported. In this paper, we presented the isolation and characterization of maize Aux/IAA genes in whole-genome scale. A total of 31 maize Aux/IAA genes (ZmIAA1 to ZmIAA31) were identified. ZmIAA genes are distributed in all the maize chromosomes except chromosome 2. Aux/IAA genes expand in the maize genome partly due to tandem and segmental duplication events. Multiple alignment and motif display results revealed major maize Aux/IAA proteins share all the four conserved domains. Phylogenetic analysis indicated Aux/IAA family can be divided into seven subfamilies. Putative cis-acting regulatory DNA elements involved in auxin response, light signaling transduction and abiotic stress adaption were observed in the promoters of ZmIAA genes. Expression data mining suggested maize Aux/IAA genes have temporal and spatial expression pattern. Collectively, these results will provide molecular insights into the auxin metabolism, transport and signaling research. 相似文献
88.
Girijavallabhan VM Chen L Dai C Feltz RJ Firmansjah L Li D Kim SH Kozlowski JA Lavey BJ Kosinski A Piwinski JJ Popovici-Muller J Rizvi R Rosner KE Shankar BB Shih NY Siddiqui MA Tong L Wong MK Yang DY Yang L Yu W Zhou G Guo Z Orth P Madison V Bian H Lundell D Niu X Shah H Sun J Umland S 《Bioorganic & medicinal chemistry letters》2010,20(24):7283-7287
Our research on hydantoin based TNF-α converting enzyme (TACE) inhibitors has led to an acetylene containing series that demonstrates sub-nanomolar potency (K(i)) as well as excellent activity in human whole blood. These studies led to the discovery of highly potent TACE inhibitors with good DMPK profiles. 相似文献
89.
Jinsong Hu Nana Dang Hui Yao Yu Li Hongxin Zhang Xiangmin Yang Jing Xu Huijie Bian Jinliang Xing Ping Zhu Zhinan Chen 《Journal of cellular and molecular medicine》2010,14(8):2132-2143
HAb18G/CD147, a glycoprotein of the immunoglobulin super‐family (IgSF), is a T cell activation‐associated molecule. In this report, we demonstrated that HAb18G/CD147 expression on both activated CD4+ and CD8+ T cells was up‐regulated. In vitro cross‐linking of T cells with an anti‐HAb18G/CD147 monoclonal antibody (mAb) 5A12 inhibited T cells proliferation upon T cell receptor stimulation. Such co‐stimulation inhibited T cell proliferation by down‐regulating the expression of CD25 and interleukin‐2 (IL‐2), decreased production of IL‐4 but not interferon‐γ. Laser confocal imaging analysis indicated that HAb18G/CD147 was recruited to the immunological synapse (IS) during T cell activation; triggering HAb18G/CD147 on activated T cells by anti‐HAb18G/CD147 mAb 5A12 strongly dispersed the formation of the IS. Further functional studies showed that the ligation of HAb18G/CD147 with mAb 5A12 decreased the tyrosine phosphorylation and intracellular calcium mobilization levels of T cells. Through docking antibody–antigen interactions, we demonstrated that the function of mAb 5A12 is tightly dependent on its specificity of binding to N‐terminal domain I, which plays pivotal role in the oligomerization of HAb18G/CD147. Taken together, we provide evidence that HAb18G/CD147 could act as a co‐stimulatory receptor to negatively regulate T cell activation and is functionally linked to the formation of the IS. 相似文献
90.
A new amperometric biosensor for the detection of sugars was prepared. A glassy carbon electrode was modified with Prussian
blue (PB) nanoparticles protected by chitosan (CS) and poly(diallyldimethylammonium chloride) (PDDA), and then gold nanoparticles
were assembled onto the electrode followed by the assembly of 4-mercaptophenylboronic acid (MPBA) onto the surface of gold
nanoparticles through a sulfur–Au bond to fabricate a self-assembled biosensor. The PB nanoparticles protected by CS and PDDA
were characterized using transmission electron microscopy and UV–vis absorption spectroscopy. The characterization of the
self-assembled electrode was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The pK
a values of the MPBA monolayer before and after combining with sugars were determined. The fabricated electrode exhibited excellent
performances for determining d(+)-glucose, d(+)-mannose, and d(−)-fructose on the basis of the change in i
p of the Fe(CN)63−/4− ion in the presence of sugars. 相似文献