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Activation of recombinant trp by thapsigargin in Sf9 insect cells 总被引:12,自引:0,他引:12
3.
Agustin Luz-Madrigal Alexander Asanov Aldo R. Camacho-Zarco Alicia Sampieri Luis Vaca 《Journal of virology》2013,87(21):11894-11907
Baculoviridae is a large family of double-stranded DNA viruses that selectively infect insects. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is the best-studied baculovirus from the family. Many studies over the last several years have shown that AcMNPV can enter a wide variety of mammalian cells and deliver genetic material for foreign gene expression. While most animal viruses studied so far have developed sophisticated mechanisms to selectively infect specific cells and tissues in an organism, AcMNPV can penetrate and deliver foreign genes into most cells studied to this date. The details about the mechanisms of internalization have been partially described. In the present study, we have identified a cholesterol recognition amino acid consensus (CRAC) domain present in the AcMNPV envelope fusion protein GP64. We demonstrated the association of a CRAC domain with cholesterol, which is important to facilitate the anchoring of the virus at the mammalian cell membrane. Furthermore, this initial anchoring favors AcMNPV endocytosis via a dynamin- and clathrin-dependent mechanism. Under these conditions, efficient baculovirus-driven gene expression is obtained. In contrast, when cholesterol is reduced from the plasma membrane, AcMNPV enters the cell via a dynamin- and clathrin-independent mechanism. The result of using this alternative internalization pathway is a reduced level of baculovirus-driven gene expression. This study is the first to document the importance of a novel CRAC domain in GP64 and its role in modulating gene delivery in AcMNPV. 相似文献
4.
Noureddine Mazoir Ahmed Benharref Laura Vaca Matías Reina Azucena Gonzlez‐Coloma 《化学与生物多样性》2020,17(9)
Semisynthetic functionalized triterpenes (4α,14‐dimethyl‐5α,8α‐8,9‐epoxycholestan‐3β‐yl acetate; 4α,14‐dimethyl‐5α‐cholest‐8‐ene‐3,7,11‐trione; 4α,14‐dimethyl‐5α‐cholesta‐7,9(11)‐dien‐3‐one and 4α,14‐dimethyl‐5α‐cholest‐8‐en‐3β‐yl acetate), previously prepared from 31‐norlanostenol, a natural insecticide isolated from the latex of Euphorbia officinarum, have been subjected to oxidation with hydrogen peroxide (H2O2) and iodosobenzene (PhIO) catalyzed by porphyrin complexes (cytochrome P‐450 models) in order to obtain optimized derivatives with high regioselectivity. The main transformations were epoxidation of the double bonds and hydroxylations of non‐activated C–H groups and the reaction products were 25‐hydroxy‐4α,14‐dimethyl‐5α‐cholesta‐7,9(11)‐dien‐3β‐yl acetate (59 %), 25‐hydroxy‐4α,14‐dimethyl‐5α‐cholest‐8‐ene‐3,7,11‐trione (60 %), 4α,14‐dimethyl‐5α,7β‐7,8‐epoxycholest‐9(11)‐en‐3‐one (22 %), 8‐hydroxy‐4α,14‐dimethyl‐5α‐cholest‐9(11)‐ene‐3,7‐dione (16 %), 12α‐hydroxy‐4α,14‐dimethyl‐5α,7β‐7,8‐epoxycholest‐9(11)‐en‐3‐one (16 %), and 4α,14‐dimethyl‐5α,8α‐8,9‐epoxycholestan‐3β‐yl acetate (26 %), respectively. We also investigated the insect (Myzus persicae, Rhopalosiphum padi and Spodoptera littoralis) antifeedant and postingestive effects of these terpenoid derivatives. None of the compounds tested had significant antifeedant effects, however, all were more effective postingestive toxicants on S. littoralis larvae than the natural compound 31‐norlanostenol, with 4α,14‐dimethyl‐5α,8α‐8,9‐epoxycholestan‐3β‐yl acetate being the most active. The study of their structure–activity relationships points out at the importance of C3 and C7 substituents. 相似文献
5.
Ben Lopman Yosselin Vicu?a Fabian Salazar Nely Broncano Matthew D. Esona Carlos Sandoval Nicole Gregoricus Michael D. Bowen Daniel Payne Martiza Vaca Martha Chico Umesh Parashar Philip J. Cooper 《PloS one》2013,8(7)
Background
We studied the transmission of rotavirus infection in households in peri-urban Ecuador in the vaccination era.Methods
Stool samples were collected from household contacts of child rotavirus cases, diarrhea controls and healthy controls following presentation of the index child to health facilities. Rotavirus infection status of contacts was determined by RT-qPCR. We examined factors associated with transmissibility (index-case characteristics) and susceptibility (household-contact characteristics).Results
Amongst cases, diarrhea controls and healthy control household contacts, infection attack rates (iAR) were 55%, 8% and 2%, (n = 137, 130, 137) respectively. iARs were higher from index cases with vomiting, and amongst siblings. Disease ARs were higher when the index child was <18 months and had vomiting, with household contact <10 years and those sharing a room with the index case being more susceptible. We found no evidence of asymptomatic infections leading to disease transmission.Conclusion
Transmission rates of rotavirus are high in households with an infected child, while background infections are rare. We have identified factors associated with transmission (vomiting/young age of index case) and susceptibility (young age/sharing a room/being a sibling of the index case). Vaccination may lead to indirect benefits by averting episodes or reducing symptoms in vaccinees. 相似文献6.
7.
Cultured cerebellar granule neurons exposed to gradual reductions in osmolarity (-1.8 mOsm/min) maintained constant volume up to -50% external osmolarity (pi(o)), showing the occurrence of isovolumetric regulation (IVR). Amino acids, Cl-, and K+ contributed at different phases of IVR, with early efflux threshold for [3H]taurine, D-[3H]aspartate (as marker for glutamate) of pi(o) -2% and -19%, respectively, and more delayed thresholds of -30% for [3H]glycine and -25% and -29%, respectively, for Cl- (125I) and K+ (86Rb). Taurine seems preferentially involved in IVR, showing the lowest threshold, the highest efflux rate (five-fold over other amino acids) and the largest cell content decrease. Taurine and Cl- efflux were abolished by niflumic acid and 86Rb by 15 mM Ba2+. Niflumic acid essentially prevented IVR in all ranges of pi(o). Cl--free medium impaired IVR when pi(o) decreased to -24% and Ba2+ blocked it only at a late phase of -30% pi(o). These results indicate that in cerebellar granule neurons: (i) IVR is an active process of volume regulation accomplished by efflux of intracellular osmolytes; (ii) the volume regulation operating at small changes of pi(o) is fully accounted for by mechanisms sensitive to niflumic acid, with contributions of both Cl- and amino acids, particularly taurine; (iii) Cl- contribution to IVR is delayed with respect to other niflumic acid-sensitive osmolyte fluxes (osmolarity threshold of -25% pi(o)); and (iv), K+ fluxes do not contribute to IVR until a late phase (< -30% pi(o)). 相似文献
8.
Teijeira F Ullán RV Guerra SM García-Estrada C Vaca I Martín JF 《The Biochemical journal》2009,418(1):113-124
The cluster of early cephalosporin biosynthesis genes (pcbAB, pcbC, cefD1, cefD2 and cefT of Acremonium chrysogenum) contains all of the genes required for the biosynthesis of the cephalosporin biosynthetic pathway intermediate penicillin N. Downstream of the cefD1 gene, there is an unassigned open reading frame named cefM encoding a protein of the MFS (major facilitator superfamily) with 12 transmembrane domains, different from the previously reported cefT. Targeted inactivation of cefM by gene replacement showed that it is essential for cephalosporin biosynthesis. The disrupted mutant accumulates a significant amount of penicillin N, is unable to synthesize deacetoxy-, deacetyl-cephalosporin C and cephalosporin C and shows impaired differentiation into arthrospores. Complementation of the disrupted mutant with the cefM gene restored the intracellular penicillin N concentration to normal levels and allowed synthesis and secretion of the cephalosporin intermediates and cephalosporin C. A fused cefM-gfp gene complemented the cefM-disrupted mutant, and the CefM-GFP (green fluorescent protein) fusion was targeted to intracellular microbodies that were abundant after 72 h of culture in the differentiating hyphae and in the arthrospore chains, coinciding with the phase of intense cephalosporin biosynthesis. Since the dual-component enzyme system CefD1-CefD2 that converts isopenicillin N into penicillin N contains peroxisomal targeting sequences, it is probable that the epimerization step takes place in the peroxisome matrix. The CefM protein seems to be involved in the translocation of penicillin N from the peroxisome (or peroxisome-like microbodies) lumen to the cytosol, where it is converted into cephalosporin C. 相似文献
9.
Juan Antonio Surez‐Cuenca Rogelio Robledo‐Nolasco Marco Antonio Alcntara‐Melndez Luis Javier Díaz Hernndez Eduardo Vera‐Gmez Alejandro Hernndez‐Patricio Karla Susana Snchez‐Díaz Juan Ariel Buendía‐Gutirrez Alejandra Contreras‐Ramos Atzin Su Ruíz‐Hernndez Rebeca Prez‐Cabeza de Vaca Paul Mondragn‐Tern 《Journal of cellular and molecular medicine》2019,23(7):4844-4849
10.
Gloria Luz Paniagua-Contreras Eric Monroy-Pérez Felipe Vaca-Paniagua José Raymundo Rodríguez-Moctezuma Erasmo Negrete-Abascal Sergio Vaca 《Annals of clinical microbiology and antimicrobials》2014,13(1):1-9