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Recombinant Virus (recombinant + virus)
Selected AbstractsEffect of prophenoloxidase expression knockout on the melanization of microfilariae in the mosquito Armigeres subalbatusINSECT MOLECULAR BIOLOGY, Issue 4 2001S. H. Shiao Abstract Melanization is an effective defence reaction used by mosquito hosts to kill malarial and filarial worm parasites. Although phenoloxidase (PO) has long been considered to be the key enzyme in the biosynthesis of melanotic material in insects, there is no direct evidence verifying its role in parasite melanization. To elucidate the role of PO in the melanization of microfilariae (mf) by mosquitoes, a double subgenomic Sindbis (dsSIN) recombinant virus was used to transduce Armigeres subalbatus mosquitoes with a 600 base antisense RNA targeted to the highly conserved copper-binding region of an Ar. subalbatus PO gene. Compared with controls, haemolymph PO activity in mosquitoes transduced with antisense RNA was significantly reduced. When these mosquitoes were challenged with Dirofilaria immitis mf, the melanization of mf was almost completely inhibited. These data verify that PO is an essential component of the biochemical pathway required for the melanization of parasites, and that the dsSIN expression system represents a useful tool in the functional analysis of endogenous gene expression in mosquitoes. [source] Antitumor effects of a recombinant fowlpox virus expressing Apoptin in vivo and in vitroINTERNATIONAL JOURNAL OF CANCER, Issue 12 2006Xiao Li Abstract Apoptin is a chicken anemia virus-derived, p53-independent, bcl-2-insensitive apoptotic protein with the ability to specifically induce apoptosis in tumor cells. To explore the use of the Apoptin gene in cancer gene therapy, we constructed a recombinant fowlpox virus expressing the Apoptin protein (vFV- Apoptin) and compared the tumor-killing activity of the recombinant virus with that of wild-type fowlpox virus in the human hepatoma cell line HepG2. We found that although cells were somewhat resistant to the basal cytotoxic effect of wild-type fowlpox virus, infection with vFV- Apoptin caused a pronounced, additional cytotoxic effect. Furthermore, cell death and disruption of tumor integrity were apparent in the vFV- Apoptin -infected cells. We also tested whether fowlpox virus-mediated expression of Apoptin in tumor cells could stimulate an antitumor effect by injecting aggressive subcutaneous tumors derived from H22 mouse hepatoma cells in C57BL/6 mice with vFV- Apoptin. We found that fowlpox virus-mediated intratumoral expression of the Apoptin gene can induce protective and therapeutic antitumor effects and significantly increase survival. Taken together, these data indicate that infection of tumors with fowlpox virus expressing Apoptin inhibits tumor growth, induces apoptosis and may be an effective cancer treatment. © 2006 Wiley-Liss, Inc. [source] A new strategy based on recombinant viruses as a tool for assessing drug susceptibility of human immunodeficiency virus type 1JOURNAL OF MEDICAL VIROLOGY, Issue 2 2007J. Garcia-Perez Abstract The emergence of drug-resistant variants during antiretroviral therapy is a serious obstacle to sustained suppression of the human immunodeficiency virus type 1 (HIV-1). For that reason, resistance assays are essential to guide clinicians in the selection of optimal treatment regimens. Genotypic assays are less expensive and results are available faster than phenotypic assays. However, in heavily experienced patients with multiple treatment failures interpretation of complex mutation patterns remains difficult, and in these cases phenotypic assays are recommended. This report describes a novel recombinant virus assay where protease (PR) and reverse transcriptase (RT) sequences derived from the plasma isolated from patients are introduced into the back-bone of an HIV molecular clone that expresses Renilla luciferase protein in the place of nef gene. All drug resistance profiles analyzed correlate with previously reported data and showed high reproducibility. This assay, in addition to a fast (completed in 10 days), precise, reproducible and automated method, presents several advantages as compared to other phenotypic assays. The system described below allows the generation of recombinant viruses with multiples cycles of replication carrying a reporter gene in their genomes. These features increase the sensitivity of the test, an important aspect to be considered in the evaluation of less fit viral isolates. In conclusion, the assay permits the quantitation of the level of resistance of clinical HIV-1 isolates to PR and RT inhibitors. J. Med. Virol. 79:127,137, 2007. © 2006 Wiley-Liss, Inc. [source] Insights into the Central Metabolism of Spodoptera frugiperda (Sf-9) and Trichoplusia ni BTI-Tn-5B1-4(Tn -5) Insect Cells by Radiolabeling StudiesBIOTECHNOLOGY PROGRESS, Issue 1 2005Chouki Benslimane The insect cell baculovirus expression vector system (BEVS) is one of the most commonly used expression systems for recombinant protein production. This system is also widely used for the production of recombinant virus and virus-like particles. Although several published reports exist on recombinant protein expression using insect cells, information dealing with their metabolism in vitro is relatively scarce. In this work we have analyzed the metabolism of glucose and glutamine, the main carbon and/or energy compounds, of the two most commonly used insect cell lines, Spodoptera frugiperda (Sf-9) and the Trichoplusia niBTI-Tn-5B1 - 4 (Tn-5). Radiolabeled substrates have been used to determine the flux of glucose carbon entering the tricarboxylic acid cycle (TCA) and the pentose phosphate (PP) pathway by direct measurement of 14CO2 produced. The percentage of total glucose metabolized to CO2 via the TCA cycle was higher in the case of the Sf-9 (2.7%) compared to Tn-5 (0.6%) cells, while the percentage of glucose that is metabolized via the PP pathway was comparable at 14% and 16% for the two cell lines, respectively. For both cell lines, the remaining 83% of glucose is metabolized through other pathways generating, for example, lactate, alanine, etc. The percentage of glutamine oxidized in the TCA cycle was approximately 5-fold higher in the case of the Tn-5 (26.1%) as compared to the Sf-9 cells (4.6%). Furthermore, the changes in the metabolic fluxes of glucose and glutamine in Tn-5-PYC cells, which have been engineered to express a cytosolic pyruvate carboxylase, have been studied and compared to the unmodified cells Tn-5. As a result of this metabolic engineering, significant increase in the percentage of glucose oxidized in the TCA cycle (3.2%) as well as in the flux through the PP pathway (34%) of the Tn-5-PYC were observed. [source] | ||||||||||