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1.
BOOK NOTICE     
Host-plant selection by phytophagous insects/by E.A. Bernays and R.F. Chapman. Published by Chapman and Hall, 1994, 312 pp., ISBN 0-412-03111-6. This is the first book that focuses on the behavior of host-plant selection by plant-feeding insects. It describes the patterns of host use, the chemical features of plants that determine host selection, the physiology of insect sensory systems, and insect behaviors, with an emphasis on mechanisms. The book also discusses genetic variability and the effects of expe-  相似文献   

2.
14-3-3 proteins--an update   总被引:15,自引:1,他引:14  
Mhawech P 《Cell research》2005,15(4):228-236
14-3-3 is a highly conserved acidic protein family, composed of seven isoforms in mammals. 14-3-3 protein can interact with over 200 target proteins by phosphoserine-dependent and phosphoserine-independent manners. Little is known about the consequences of these interactions, and thus are the subjects of ongoing studies. 14-3-3 controls cell cycle, cell growth, differentiation, survival, apoptosis, migration and spreading. Recent studies have revealed new mechanisms and new functions of 14-3-3, giving us more insights on this fascinating and complex family of proteins. Of all the seven isoforms, 14-3-3σ seems to be directly involved in human cancer. 14-3-3σ itself is subject to regulation by p53 upon DNA damage and by epigenetic deregulation. Gene silencing of 14-3-3σ by CpG methylation has been found in many human cancer types. This suggests that therapy-targeting 14-3-3σ may be beneficial for future cancer treatment.  相似文献   

3.
嗜碱芽孢杆菌N6-27碱性纤维素酶的纯化及性质   总被引:4,自引:0,他引:4  
The alkaline cellulase produced by alkalophilic Bacillus sp. N6-27 was purified to electrophoresis homogeneity by (NH4)2SO4 fractionation, Sepharose CL-4B hydrophobic interaction chromatography, Bio-gel P-150 chromatography. The molecular weight and pI determined by SDS-PAGE and by PAGE-IEF were 94000 and 4.2,respectively. The optimum temperature and PH for the enzymatic catalysis were 55℃ and 8.5, respectively. The enzyme activity was stable under 50℃ and in the PH range of 6-11. The substrate was carboxy…  相似文献   

4.
1. Coptotermes guangzhouensis, sp. n. This new sepcies can be pesarated from C.formosanus Shiraki, by thelength of left mandble<0.95, by the posterior margin of pronotum almoststraight, and by the width of head 0.99-1.12 (1.06).  相似文献   

5.
黑色素抑制流感病毒诱导宿主细胞凋亡   总被引:9,自引:0,他引:9  
The apoptosis induced by influenza virus in cultured MDCK cells was reported and the selective inhibitory effect of melamin on the apoptosis induced by influenza virus was investigated. The results showed that the DNA ladder could be first detected at 6 h post-infection (p.i.), accompanied by nuclear condensation and nuclear fragmentation could be easily detected at 12 h p.i. In addition, the apoptosis-induced activity of influenza virus A1/Jingfang 86-1 strain was more potent than that of B/Hufang 93-1 strain (P<0.05). In the range of 20-125 μg/mL, melanin was found to significantly (P<0.001) inhibit apoptosis induced by 64 hemagglutination unit influenza virus infection with a inhibitory rate comparable to that obtained by virazole and showed no cytotoxicity. The inital results suggested that the mechanism of melanin against the apoptosis induced by influenza virus was related to the blockage of viruses' adsorbtion to the host cells.  相似文献   

6.
To overexpress EBNA-1 in E.coli and generate the specific antibody,in this study,the antigenicity,epitope and hydrolysis of EBNA-1 were analyzed using the computer design software Biosun.Based on the prediction by computer analysis,the sequence encoding EBNA-1385-557 was amplified by PCR with the specific primers.The expression vector containing EBNA-1385-557 coding sequence was constructed.His-tagged EBNA-1385-557 was expressed in E.coli.The soluble recombinant protein was purified using Ni-NTA chromato...  相似文献   

7.
Two new stllbenes with two Isoprenoid groups, namely artostllbenes A (compound 1) and B (compound 2), were Isolated from the stems of Arfocarpus chama Buch.-Ham. by repeated column chromatography. The& structures were elucldated as (E)-4-[2-(7-meth-xy-2-2-d-methy-6-(3-methy-but-2-eny-)-2H-1-benz-pyran-5-y-)v-ny-]benzene-1- 2-dlol (compound 1) and (Z)-4-[2-(7-meth-xy-2-2-dimethy--6-(3-methy-but-2-eny-)-2H-1-benz-pyran-5-y-)v-ny-]ben- zene-l,2-dlol (compound 2) by spectroscopic methods, mainly by 1D-, 2D-NMR and MS spectra. Compounds 1 and 2 are two cls- and trans-lsomers and compound 2 is the flrst cis-stllbene isolated from Moraceous plants.  相似文献   

8.
王润华 《蛇志》2003,15(4):57-65
The research projects were supported by a research scholarship from the National University of Singapore, Singapore and by a fund from The National Bureau of Foreign Talents, China [2001-151] .  相似文献   

9.
Beginning to understand microRNA function   总被引:2,自引:0,他引:2  
Du T  Zamore PD 《Cell research》2007,17(8):661-663
MicroRNAs (miRNAs) are -22 nt small RNAs expressed by plants, animals, viruses and at least one unicellular organism, the green alga, Chlamydomonas reinhardtii. Most miRNAs are transcribed as primary miRNAs (pri-miRNAs) by RNA polymerase Ⅱ, although a few are transcribed by RNA polymerase Ⅲ. In animals, pri-miRNAs are converted to mature miRNAs by two successive endonucleolytic cleavages.[第一段]  相似文献   

10.
11.
NKX3.1 is a prostate-specific homeobox gene related to prostate development and prostate cancer. In this work, we aimed to identify precisely the functional cis-element in the 197 bp region (from -1032 to -836 bp) of the NKX3.1 promoter (from -1032 to +8 bp), which was previously identified to present positive regulatory activity on NKX3.1 expression, by deletion mutagenesis analysis and electrophoretic mobility shift assay (EMSA). A 16 bp positive cis-element located between -920 and -905 bp upstream of the NKX3.1 gene was identified by deletion mutation analysis and proved to be a functional positive cis-element by EMSA. It will be important to further study the functions and regulatory mechanisms of this positive cis-element in NKX3.1 gene expression.  相似文献   

12.
The unicellular halotolerant alga Dunaliella salina had the ability to oxidize NADH and reduce Fe(CN)6^3-.The redox reactions were to some extent stimulated by slight hyperosmotic shock (2.0mol/L→2.6mol/L NaCl),but markably inhibited by abrupt hyperosmotic shock (2.0mol/L→3.5mol/L NaCl) and hypoosmotic shock (2.0mol/L→1.0mol/L NaCl;2.0mol/L→0.67mol/L NaCl).With the adaptation of algal cells to osmotic shock by accumulating or degraging intracellular grycerol,the plasmalemma redox activities were also restored.The O2 uptake stimulated by NADH could be promoted by FA and SHAM.Hypoosmotic shock increases the basal respiration rate of alga cells,but weakened the stimulating effects of NADH,FA and SHAM on O2 uptake.On the other hand,hyperosmotic shock reduced the basal respiration rate,but relatively enhanced the above effects of NADH,FA and SHAM.H^ extrusion of alga cells was inhibited by NADH and stimulated by Fe(CN)6^3-.Vanadate and DES could inhibit H^ efflux,but had little effect in the presence of NADH and Fe(CN)6^3-.Both hyperand hypoosmotic shock stimulated H^ extrusion.This effect could be totally inhibited by vanadate and DES,but almost unaffected by 8-hydroxyquinoline.It was suggested that H^ -ATPase probably played a more important role in H^ extrusion and osmoregulation under the conditions of osmotic shock.  相似文献   

13.
The vascular endothelial growth factor (VEGF) receptor Flt-1 is charaterized by seven Ig-like loops within the extracellular domain. To identify which part is responsible for ligand binding, four cDNA clones coding for truncated Flt-1 mutants consisting of loop 1, 1-2, 2-3 and 1-3 were obtained by PCR from human cardiac cDNA library and inserted into the vectors of the yeast two-hybrid system, with VEGF cDNA on the partner plasmid. The paired plasmids were transformed into yeast strain SFY526, and tested by filter membrane method and β-galactosidase activity. The results showed that Flt-1(1-2)、Flt-1(2-3) and Flt-1(1-3) all were able to bind VEGF, of which Flt-1(1-3) showed the highest binding affinity, but no binding of VEGF was observed with Flt-1(2) and VEGF.  相似文献   

14.
A phosphetase that hydrolyses phosphate monoesters has been Isolated from wheat thylakold membranes. Biochemical properties and inhibition kinetics of the phosphatase were Investigated using several Ions, organlc solvents, and Inhlbltors. Wheat (Trltlcum aestivum L. cv. PH82-2-2) thylakold membrane phosphatase activity was activated by Mg^2+, Ca^2+, and Fe^2+ and was inhibited by Mn^2+ and Cu^2+. For example, enzyme activity was acUvated 34.81% by 2 mmol/l. Mg^2+, but was Inhibited 22.3% and 8.5% by 2 and 1 mmol/L Cu^2+, respectively. Methanol, ethanol and glycol were all able to activate enzyme activity. Enzyme activity was activated 58.5%, 48.2%, and 8.7% by 40% ethanol, methanol and glycol, respectively. From these results, It can be seen that the degree of actlvetlon of the phosphetase was greatest for ethanol and the type of acUvatlon was uncompetltlve. Moreover, the activity of the thylakold membrane phosphetase was Inhibited by molybdate, vanadete, phosphate, and fluoride and the type of Inhibition produced by these elements was uncompetltlve, non-competitive, competltlve and mixed, respectively.  相似文献   

15.
Sheng H  Wang Y  Jin Y  Zhang Q  Zhang Y  Wang L  Shen B  Yin S  Liu W  Cui L  Li N 《Cell research》2008,18(8):846-857
Bone-marrow-derived mesenchymal stem cells (MSCs) have been shown to possess immunosuppressive properties, e.g., by inhibiting T cell proliferation. Activated T cells can also enhance the immunosuppression ability of MSCs. The precise mechanisms underlying MSC-mediated immunosuppression remain largely undefined, although both cell-cell contact and soluble factors have been implicated; nor is it clear how the immunosuppressive property of MSCs is modulated by T cells. Using MSCs isolated from mouse bone marrow, we show here that interferon gamma (IFNγ), a well-known proinflammatory cytokine produced by activated T cells, plays an important role in priming the immunosuppressive property of MSCs. Mechanistically, IFNγ acts directly on MSCs and leads to up-regulation of B7-H1, an inhibitory surface molecule in these stem cells. MSCs primed by activated T cells derived from IFNγ-/- mouse exhibited dramatically reduced ability to suppress T cell proliferation, a defect that can be rescued by supplying exogenous IFNγ. Moreover, siRNA-mediated knockdown of B7-H1 in MSCs abolished immunosuppression by these cells. Taken together, our results suggest that IFNγ plays a critical role in triggering the immunosuppresion by MSCs through upregulating B7-H1 in these cells, and provide evidence supporting the cell-cell contact mechanism in MSC-mediated immunosuppression.  相似文献   

16.
Objective: To investigate the effect of Iptakalim(Ipt) preventing injury of endothelial microvesicles(EMVs) derived from hypoxia/reoxygenation(H/R)-treated HUVECs on the relaxation of rat thoracic aortic rings and explore the underlying mechanism. Methods: H/R injury model was established to release H/R-EMVs from HUVECs. H/R-EMVs from HUVECs were isolated by ultracentrifugation from the conditioned culture medium. H/R-EMVs were characterized by using Transmission Electron Microscope(TEM). Thoracic aortic rings of rats were incubated with 10~(-7)-10~(-3 )mol/L Ipt and co-cultured with 10 μg/ml H/R-EMVs for 4 hours, and their endothelium- dependent relaxation in response to acetylcholine(ACh) was recorded in vitro. The nitric oxide(NO) production of ACh-treated rat thoracic aortic rings was measured by using Griess reagent. The expression of endothelial NO synthase(e NOS), phosphorylated e NOS(p-e NOS, Ser-1177), serine/threonine kinas(Akt) and phosphorylated Akt(p-Akt, Ser-473) in the thoracic aortic rings of rats was detected by Western blotting. Results: H/R-EMVs were induced by H/R-treated HUVECs and isolated by ultracentrifugation. The isolated H/R-EMVs subjected to TEM revealed small, rounded vesicles(100–1 000 nm) surrounded by a membrane. H/R-EMVs impaired relaxation induced by ACh of rat thoracic aortic rings significantly. Compared with H/R-EMVs treatment individually, relaxation and NO production of rat thoracic aortic rings were increased by Ipt treatment in a concentration-dependent manner(P0.05, P0.01). The expression of total e NOS(t-e NOS) and total Akt(t-Akt) was not affected by Ipt or H/R-EMVs. However, the expression of p-e NOS and p-Akt increased after treated with Ipt(P0.01). Conclusion: Based on H/R-EMVs treatment, ACh induced endothelium-dependent relaxation of rat thoracic aortic rings was ameliorated by Ipt in a concentration-dependent manner. The mechanisms involved the increase in NO production, p-e NOS and p-Akt expression.  相似文献   

17.
The purpose of this study is to explore and develop a novel biocompatibility drug delivery carrier for controllingontrolled drug release. The a-eleostearic acid grafted hydroxyapatite (a-ESA-g-HA) composite was synthesized by using silane coupling agent and characterized by Fourier Transformation Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscope (SEM), respectively. The in vitro drug loading and controlled release behaviors of a-ESA-g-HA composite were investigated using ciprofloxacin as the model drug. The amount of ciprofloxacin loading and released was cal- culated by absorbance value which was determined by UV-Vis spectrophotometry at wavelength of 277 nm. The biocompatibility of a-ESA-g-HA composite was assessed by 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-di-phenytetrazoliumromide(MTT) assay, nuclear morphology and platelet adhesion. The results showed that the a-ESA-g-HA had nontoxic and good biocompatibility. According to the results mentioned above, the a-ESA-g-HA is an effective drug delivery carrier, which could increase drug loading capacity and control drug release, so further studies are necessary to evaluate clinical application and human health care.  相似文献   

18.
Aims and Scope
Genomics, Proteomics & Bioinformatics (GPB, ISSN 1672-0229) is a peer-reviewed international journal in English since 2003. GPB is sponsored by Beijing Institute of Genomics, Chinese Academy of Sciences and Genetics Society of China, and jointly published bimonthly by Elsevier and Science Press.  相似文献   

19.
The crystal structure of an acidic neurotoxin, BmK M8, from Chinese scorpion Buthus martensii Karsch was determined at 0.25 nm resolution. The X-ray diffraction data of BmK M8 crystals at 0.25nm resolution were collected on a Siemens area detector. Using molecular replacement method with a basic scorpion toxin AaH II in a search model, the cross-rotation function, PC-refinement and translation function were calculated by X-PLOR program package. The correct orientation and position of BmK M8 molecule in crystal were determined in a resolution range of 1.5 - 0.35nm, The oystallographic refinement was further performed by stereo-chemical restrict least-square technique, followed by simulated annealing, slow-cooling protocols. The final crystallographic R-factor at 0.8-0.25 nm is 0.171. The standard deviations of bond length and bond angle from ideality are 0.001 7nm and 2.24° , respectively. The final model of BmK M8 structure is composed of a dense core of secondary structure elements by a stretch of α-  相似文献   

20.
Most of the materials studied by Dr Schenkel were deposited in Paris, only a small part deposited in Natural History Museum of Basel (NMB), including 7 linyphiid species collected from China. These comprise two parts: one part was collected by muscovite tourist/researcher G. N. Potanin between 1885-1886; another part was collected by Dr D. Hummel in an expedition to Northwest China under the leadership of Dr S. Hedin and Prof.  相似文献   

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