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31.
Sandor Keszthelyi David Szollosi Lilia Strobe Szabolcs Osvath Krisztian Szigeti Zsolt Pbnya Adam Csoka Tamas Donko 《Insect Science》2021,(1):281-284
Dear Editor,There are several arthropods,which live and develop covertly in plant tissues.The plant tissues surrounding them provide them with shelter during their vulnerable developing stage or ensure overwintering as well as they can supply them with essential food for their ontogenetic development(McNaughton,1983). 相似文献
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33.
Full-length prion protein aggregates to amyloid fibrils and spherical particles by distinct pathways
As limited structural information is available on prion protein (PrP) misfolding and aggregation, a causative link between the specific (supra)molecular structure of PrP and transmissible spongiform encephalopathies remains to be elucidated. In this study, high pressure was utilized, as an approach to perturb protein structure, to characterize different morphological and structural PrP aggregates. It was shown that full-length recombinant PrP undergoes beta-sheet aggregation on high-pressure-induced destabilization. By tuning the physicochemical conditions, the assembly process evolves through two distinct pathways leading to the irreversible formation of spherical particles or amyloid fibrils, respectively. When the PrP aggregation propensity is enhanced, high pressure induces the formation of a partially unfolded aggregated protein, Agg(HP), which relaxes at ambient pressure to form amorphous aggregates. The latter largely retain the native secondary structure. On prolonged incubation at high pressure, followed by depressurization, Agg(HP) transforms to a monodisperse population of spherical particles of about 20 nm in diameter, characterized by an essentially beta-sheet secondary structure. When the PrP aggregation propensity is decreased, an oligomeric reaction intermediate, I(HP), is formed under high pressure. After pressure release, I(HP) relaxes to the original native structure. However, on prolonged incubation at high pressure and subsequent depressurization, it transforms to amyloid fibrils. Structural evaluation, using optical spectroscopic methods, demonstrates that the conformation adopted by the subfibrillar oligomeric intermediate, I(HP), constitutes a necessary prerequisite for the formation of amyloids. The use of high-pressure perturbation thus provides an insight into the molecular mechanism of the first stages of PrP misfolding into amyloids. 相似文献
34.
Veettil MV Sadagopan S Sharma-Walia N Wang FZ Raghu H Varga L Chandran B 《Journal of virology》2008,82(24):12126-12144
Kaposi's sarcoma-associated herpesvirus (KSHV) interacts with cell surface heparan sulfate (HS) and α3β1 integrin during the early stages of infection of human dermal microvascular endothelial cells (HMVEC-d) and human foreskin fibroblasts (HFF), and these interactions are followed by virus entry overlapping with the induction of preexisting host cell signal pathways. KSHV also utilizes the amino acid transporter protein xCT for infection of adherent cells, and the xCT molecule is part of the cell surface heterodimeric membrane glycoprotein CD98 (4F2 antigen) complex known to interact with α3β1 and αVβ3 integrins. KSHV gB mediates adhesion of HMVEC-d, CV-1, and HT-1080 cells and HFF via its RGD sequence. Anti-αV and -β1 integrin antibodies inhibited the cell adhesion mediated by KSHV-gB. Variable levels of neutralization of HMVEC-d and HFF infection were observed with antibodies against αVβ3 and αVβ5 integrins. Similarly, variable levels of inhibition of virus entry into adherent HMVEC-d, 293 and Vero cells, and HFF was observed by preincubating virus with soluble α3β1, αVβ3, and αVβ5 integrins, and cumulative inhibition was observed with a combination of integrins. We were unable to infect HT1080 cells. Virus binding and DNA internalization studies suggest that αVβ3 and αVβ5 integrins also play roles in KSHV entry. We observed time-dependent temporal KSHV interactions with HMVEC-d integrins and CD98/xCT with three different patterns of association and dissociation. Integrin αVβ5 interaction with CD98/xCT predominantly occurred by 1 min postinfection (p.i.) and dissociated at 10 min p.i., whereas α3β1-CD98/xCT interaction was maximal at 10 min p.i. and dissociated at 30 min p.i., and αVβ3-CD98/xCT interaction was maximal at 10 min p.i. and remained at the observed 30 min p.i. Fluorescence microscopy also showed a similar time-dependent interaction of αVβ5-CD98. Confocal-microscopy studies confirmed the association of CD98/xCT with α3β1 and KSHV. Preincubation of KSHV with soluble heparin and α3β1 significantly inhibited this association, suggesting that the first contact with HS and integrin is an essential element in subsequent CD98-xCT interactions. Anti-CD98 and xCT antibodies did not block virus binding and entry and nuclear delivery of viral DNA; however, viral-gene expression was significantly inhibited, suggesting that CD98-xCT play roles in the post-entry stage of infection, possibly in mediating signal cascades essential for viral-gene expression. Together, these studies suggest that KSHV interacts with functionally related integrins (αVβ3, α3β1, and αVβ5) and CD98/xCT molecules in a temporal fashion to form a multimolecular complex during the early stages of endothelial cell infection, probably mediating multiple roles in entry, signal transduction, and viral-gene expression. 相似文献
35.
Revesz L Blum E Di Padova FE Buhl T Feifel R Gram H Hiestand P Manning U Neumann U Rucklin G 《Bioorganic & medicinal chemistry letters》2006,16(2):262-266
A test library with three novel p38alpha inhibitory scaffolds and a narrow set of substituents was prepared. Appropriate combination of substituent and scaffold generated potent p38alpha inhibitors, for example, pyrazolo[3,4-b]pyridine 9, pyrazolo[3,4-d]pyrimidine 18a and pyrazolo[3,4-b]pyrazine 23b with potent in vivo activity upon oral administration in animal models of rheumatoid arthritis. 相似文献
36.
Laszlo Ambrus Sam H. Thal Selig B. Weinstein Juanita Warnecke 《The Western journal of medicine》1967,106(5):354-358
Following a six-week program of training in a series of exercises, a significant number of patients with chronic obstructive pulmonary emphysema showed decided improvement in functional activity. Subjective improvement also was noted and kept the patient motivation high.Preliminary observations indicated that the improvement could be maintained long after the end of the training period. 相似文献
37.
A variant of KCC2 from patients with febrile seizures impairs neuronal Cl− extrusion and dendritic spine formation 下载免费PDF全文
Martin Puskarjov Patricia Seja Sarah E Heron Tristiana C Williams Faraz Ahmad Xenia Iona Karen L Oliver Bronwyn E Grinton Laszlo Vutskits Ingrid E Scheffer Steven Petrou Peter Blaesse Leanne M Dibbens Samuel F Berkovic Kai Kaila 《EMBO reports》2014,15(6):723-729
Genetic variation in SLC12A5 which encodes KCC2, the neuron-specific cation-chloride cotransporter that is essential for hyperpolarizing GABAergic signaling and formation of cortical dendritic spines, has not been reported in human disease. Screening of SLC12A5 revealed a co-segregating variant (KCC2-R952H) in an Australian family with febrile seizures. We show that KCC2-R952H reduces neuronal Cl− extrusion and has a compromised ability to induce dendritic spines in vivo and in vitro. Biochemical analyses indicate a reduced surface expression of KCC2-R952H which likely contributes to the functional deficits. Our data suggest that KCC2-R952H is a bona fide susceptibility variant for febrile seizures. 相似文献
38.
Ramesh N. Patel Robert S. Robison Laszlo J. Szarka 《Applied microbiology and biotechnology》1990,34(1):10-14
Summary A key intermediate (S(–) 2-cyclohexyl-1,3-propanediol monoacetate) was made with high optical purity for the total synthesis of a new angiotensin converting enzyme inhibitor, Fosinopril. The stereoselective hydrolysis of 2-cyclohexyl-1,3-propanediol diacetate (I) and 2-phenyl-1,3-propanediol diacetate (II) was carried out with lipases. Among various lipases evaluated, only porcine pancreatic lipase (PPL) and Chromobacterium viscosum lipase demonstrated efficient conversion and gave the desired enantiomer of monoacetate. In aqueous solution, the desired S(–) monoacetate exhibited an optical purity of 65%–80% (30%–60% enantiomeric excess [e.e.]). However, when the same reactions were conducted in a biphasic system, the product S(–) monoacetate exhibited an optical purity of 99%–100% (98%–100% e.e.). The high purity product was achieved with 65 mol% yield at 1% substrate concentration. Among various solvents evaluated in biphasic systems, efficient hydrolysis was achieved in toluene, cyclohexane, and trichloro-trifluoroethane. The crude PPL was partially purified and two lipase fractions (A and B) were identified. Lipases A and B had a molecular mass of 38 000 and 40 000 daltons, respectively, and both were found to catalyze the hydrolysis of I and II to the appropriate monoacetate in a biphasic system.
Offprint requests to: R. N. Patel 相似文献
39.
Ronald L. Hanson Kenneth S. Bembenek Ramesh N. Patel Laszlo J. Szarka 《Applied microbiology and biotechnology》1992,37(5):599-603
Summary Biotransformations were developed to oxidize N-carbobenzoxy(CBZ)-l-lysine and to reduce the product keto acid to l-CBZ-oxylysine. Lysyl oxidase (l-lysine: O2 oxidoreductase, EC 1.4.3.14) from Trichoderma viride was relatively specific for l-lysine and had very low activity with N-substituted derivatives. l-Amino acid oxidase (l-amino acid: O2 oxidoreductase [deaminating], EC 1.4.3.2) from Crotalus adamanteus venom had low activity with l-lysine but high activity with N-formyl-, t-butyoxycarbonyl(BOC)-, acetyl-, trifluoroacetyl-, or CBZ-l-lysine. l-2-Hydroxyisocaproate dehydrogenase (EC 1.1.1.-) from Lactobacillus confusus catalyzed the reduction by NADH of the keto acids from N-acetyl-, trifluoroacetyl-, formyl- and CBZ-l-lysine but was inactive with the products from oxidation of l-lysine, l-lysine methyl ester, l-lysine ethyl ester or N-t-BOC-l-lysine. Providencia alcalifaciens (SC9036, ATCC 13159) was a good microbial substitute for the snake venom oxidase and also provided catalase (H2O2:H2O2 oxidoreductase EC 1.11.1.6). N-CBZ-l-Lysine was converted to CBZ-l-oxylysine in 95% yield with 98.5% optical purity by oxidation using P. alcalifaciens cells followed by reduction of the keto acid using l-2-hydroxyisocaproate dehydrogenase. NADH was regenerated using formate dehydrogenase (formate: NAD oxidoreductase, EC 1.2.1.2) from Candida boidinii. The Providencia oxidase was localized in the particulate fraction and catalase activity was predominantly in the soluble fraction of sonicated cells. The pH optima and kinetic constants were determined for the reactions.
Correspondence to: R. L. Hanson 相似文献
40.
Mizuno S Yasuo M Bogaard HJ Kraskauskas D Alhussaini A Gomez-Arroyo J Farkas D Farkas L Voelkel NF 《PloS one》2012,7(1):e30678