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PubMed1990

Expression of influenza A and B virus nucleoprotein antigens in baculovirus.

Full-length cDNA clones of the nucleoprotein (NP) genes of influenza A/Ann Arbor/6/60 and B/Ann Arbor/1/86 viruses were constructed from virion RNA and subsequently expressed in Spodoptera frugiperda (Sf9) cells using the baculovirus vector, Autographa californica nuclear polyhedrosis virus. Western blot analysis of lysates prepared from Sf9 cells infected with the recombinant viruses confirmed that the baculovirus-expressed NP antigens were reactive with monoclonal antibodies specific for either type A or B NP and with anti-NP antibodies in human serum samples. Electrophoretic analysis indicated that the expressed NP antigens comigrated with NP purified from influenza A or B virions and that the recombinant NP antigens represented greater than 10% of total protein in infected cells. Dilutions of clarified Sf9 cell lysates were used as antigens in a standard enzyme immunoassay to detect serum antibody specific for influenza A or B viruses. The results from assays using the baculovirus-expressed NP antigens showed good correlation with the results obtained using bacterially expressed NP antigen as well as complement fixation. Therefore, baculovirus-expressed NP antigens have the potential to be used to develop reproducible and routine assays for the serodiagnosis of influenza virus infections as an alternative to the complement fixation or haemagglutination inhibition tests.

Adult↗
PubMed1976

Biochemical, biophysical, and biological properties of densonucleosis virus. I. Structural proteins.

The polypeptide composition of highly purified densonucleosis virus was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The viral proteins showed a different behavior in sodium dodecyl sulfate-gels in comparison with the marker proteins. Therefore, the molecular weights were estimated by analyzing the retardation of the electrophoretic mobility of these proteins in gels with increasing polyacrylamide concentrations. Four structural proteins with molecular weights of 49,000, 58,500, 69,000, and 98,000 were found, ant they were designated p49, p59, p69, and p98, respectively. There are several indications that p98 is a dimer of p49. The relative quantity of the structural proteins in a virion suggests that at least p49 (accounting for +/-70% of total protein mass) is a capsid protein and that there will be 12 capsomers per virion.

Animals↗
PubMed1979

Biophysical and biochemical characterization of five animal viruses with bisegmented double-stranded RNA genomes.

Infectious pancreatic necrosis virus of fish, infectious bursal disease virus of chickens, Tellina virus and oyster virus of bivalve molluscs, and drosophila X virus of Drosophila melanogaster are naked icosahedral viruses with an electron microscopic diameter of 58 to 60 nm. The genome of each of these viruses consists of two segments of double-stranded RNA (molecular weight range between 2.6 x 10(6) and 2.2 x 10(6), and the virion, capsid proteins fall into three size class categories (large, medium, and small; ranging from 100,000 to 27,000) as determined by polyacrylamide slab gel electrophoresis. The hydrodynamic properties of the five viruses are similar as determined by analytical ultracentrifugation and laser quasi-elastic, light-scattering spectroscopy. The calculated particle weights range between 55 x 10(6) and 81 x 10(6). Tryptic peptide comparisons of 125I-labeled virion proteins showed that five viruses are different from each other, although there was considerable overlap in the peptide maps of the three aquatic viruses, indicting a degree of relatedness. Cross-neutralization tests indicated that drosophila X, infectious pancreatic necrosis, and infectious bursal disease viruses were different from each other and from oyster and Tellina viruses. The same test showed oyster and Tellina viruses to be related. The biochemical and biophysical properties of the five viruses cannt be included in the family Reoviridae or in any of the present virus genera.

Animals↗
PubMed1987

Expression of polyomavirus large T antigen by using a baculovirus vector.

A gene encoding the large T antigen of polyomavirus was inserted into the baculovirus Autographa californica nuclear polyhedrosis virus so that gene expression was under the control of the strong, very late polyhedrin gene promoter. Significantly more large T antigen was produced in recombinant virus-infected insect cells than was observed in polyomavirus-transformed mouse cells. The insect-derived T antigen exhibited polyomavirus origin-specific DNA binding. The baculovirus expression system provides a convenient source of T antigen for in vitro studies.

Animals↗
PubMed2005

Ikappabeta-related vankyrin genes in the Campoletis sonorensis ichnovirus: temporal and tissue-specific patterns of expression in parasitized Heliothis virescens lepidopteran hosts.

Polydnaviruses (PDVs) are unusual insect viruses that occur in obligate symbiotic associations with parasitic ichneumonid (ichnoviruses, or IVs) and braconid (bracoviruses, or BVs) wasps. PDVs are injected with eggs, ovarian proteins, and venom during parasitization. Following infection of cells in host tissues, viral genes are expressed and their products function to alter lepidopteran host physiology, enabling endoparasitoid development. Here we describe the Campoletis sonorensis IV viral ankyrin (vankyrin) gene family and its transcription. The seven members of this gene family possess ankyrin repeat domains that resemble the inhibitory domains of the Drosophila melanogaster NF-kappabeta transcription factor inhibitor (Ikappabeta) cactus. vankyrin gene expression is detected within 2 to 4 h postparasitization (p.p.) in Heliothis virescens hosts and reaches peak levels by 3 days p.p. Our data indicate that vankyrin genes from the C. sonorensis IV genome are differentially expressed in the tissues of parasitized hosts and can be divided into two subclasses: those that target the host fat body and those that target host hemocytes. Polyclonal antibodies raised against a fat-body targeting vankyrin detected a 19-kDa protein in crude extracts prepared from the 3 days p.p. fat body. Vankyrin-specific Abs localized to 3-day p.p. fat-body and hemocyte nuclei, suggesting a role for vankyrin proteins in the nuclei of C. sonorensis IV-infected cells. These data are evidence for divergent tissue specificities and targeting of multigene families in IVs. We hypothesize that PDV vankyrin genes may suppress NF-kappabeta activity during immune responses and developmental cascades in parasitized lepidopteran hosts of C. sonorensis.

Amino Acid Sequence↗
PubMed2004

Polydnavirus genes and genomes: emerging gene families and new insights into polydnavirus replication.

Polydnavirus genome sequencing is providing new insights into viral genome organization and viral gene function. Sequence analyses demonstrate that the genomes of these viral mutualists are largely noncoding but maintain genes and gene families that are unrelated to other viral genes. Interestingly, these organizational patterns in polydnavirus genomes are evident in both the bracovirus and ichnovirus genera, even though these two genera are evolutionarily unrelated. The identity and function of some polydnavirus gene families are considered with some functions experimentally supported and others implied by homology relationships with known insect genes. The evidence relative to polydnavirus origins and evolution is considered but remains an area of speculation. However, sequencing of these viral genomes has been informative and provides opportunities for productive investigation of these unusual mutualistic insect viruses.

Animals↗
PubMed2003

Baculoviruses as Vectors for Gene Therapy against Human Prostate Cancer.

Current curative strategies for prostate cancer are restricted to the primary tumour, and the effect of treatments to control metastatic disease is not sustained. Therefore, the application of gene therapy to prostate cancer is an attractive alternative. Baculoviruses are highly restricted insect viruses, which can enter, but not replicate in mammalian cells. Baculoviruses can incorporate large amounts of extra genetic material, and will express transgenes in mammalian cells when under the control of a mammalian or strong viral promoter. Successful gene delivery has been achieved both in vitro and in vivo and into both dividing and nondividing cells, which is important since prostate cancers divide relatively slowly. In addition, the envelope protein gp64 is sufficiently mutable to allow targeted transduction of particular cell types. In this review, the advantages of using baculoviruses for prostate cancer gene therapy are explored, and the mechanisms of viral entry and transgene expression are described.

Journal Article↗
PubMed1979

Physicochemical characterization of a small RNA virus associated with baculovirus infection in Trichoplusia ni.

An RNA virus was isolated from Trichoplusia ni larvae infected with inoculum of the baculovirus of Autographa californica. Physicochemical characterization has revealed a 35-nm virus with a density in CsCl of 1.3 g/cm3 and a sedimentation coefficient of 200S. The virus consisted of 10--15% single-stranded RNA with an apparent molecular weight of 1.9 x 10(6) and coat protein with a subunit size of 67,000. The virus is similar to the Nudaurelia capensis beta virus and also possesses some interesting similarities to the mammalian caliciviruses. The proposed cryptogram of the virus is R/1:1.9/12:S/S:I/O.

Animals↗
PubMed2005

Functional display of an alpha2 integrin-specific motif (RKK) on the surface of baculovirus particles.

The use of baculovirus vectors shows promise as a tool for gene delivery into mammalian cells. These insect viruses have been shown to transduce a variety of mammalian cell lines, and gene transfer has also been demonstrated in vivo. In this study, we generated two recombinant baculovirus vectors displaying an integrin-specific motif, RKK, as a part of two different loops of the green fluorescent protein (GFP) fused with the major envelope protein gp64 of Autographa californica M nucleopolyhedrovirus. By enzyme linked immunosorbent assays, these viruses were shown to bind a peptide representing the receptor binding site of an alpha2 integrin, the alpha2I-domain. However, the interaction was not strong enough to overcome binding of wild type gp64 to the unknown cellular receptor(s) on the surface of alpha2 integrin-expressing cells (CHO-alpha2beta1) or enhance the viral uptake. After treatment of these cells with phospholipase C, internalization of all viruses was blocked or decreased significantly. However, one of the RKK displaying viruses, AcGFP(K)gp64, was still able to internalize into CHO-alpha2beta1 cells, although at a lower level as compared to non-treated cells. This may indicate the possible utilization of a PLC independent alternative route via, in this case, the alpha2beta1 integrin.

Amino Acid Motifs↗
PubMed2000

[Potential health-protective effects of food-derived flavonoids].

The flavonoids similarly to the other phenolic substances are secondary products of the plant metabolism. Their basic role is the defence of the plant cell from different damaging agents such as UV light, fungus, insects, viruses and oxygen free radicals. Laboratory and epidemiological studies have proved their wide-range chemical, biological and biochemical effects. Their beneficial action is unquestionable in preservation of health and prevention of diseases. The author presents the chemical structure, biochemical effects of the most frequently studied flavonoids, their metabolism and bioavailability, the flavonoid intake of the population, and the possible side effect of the components.

Anticarcinogenic Agents↗
PubMed2002

Baculovirus studies in new, indigenous lepidopteran cell lines.

Eight lepidopteran cell lines were established recently and their susceptibility to different insect viruses was studied. Two Spodoptera litura cell lines from the larval and pupal ovaries, were found highly susceptible to S. litura nuclear polyhedrosis virus (SLNPV, 5-6 x 10(6) NPV/ml). The Helicoverpa armigera cell line from the embryonic tissue was highly susceptible to H. armigera NPV (HaNPV, 6.3 x 10(6) NPV/ml). These in vitro grown SLNPV and HaNPV caused 100% mortality to respective 2nd instar larvae. The susceptibility of the cryo-preserved cell lines to respective baculoviruses (SLNPV/HaNPV) was studied and no significant difference in their susceptibility status was observed. The cultures could grow as suspension culture on shakers and may find application for in vitro production of wild type/recombinant baculoviruses as bio-insecticides. S. litura and Bombyx mori cell lines from larval ovaries, were highly susceptible to Autographa californica NPV (5.5 x 10(6) NPV/ml) and Bombyx mori NPV (BmNPV, 6.1 x 10(6) NPV/ml) respectively. These cell lines may find application in baculovirus expression vector studies for the production of recombinant proteins, useful in the development of diagnostic kits or as vaccines.

Animals↗