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At least 1,063 records · Page 59Linked to original sources
PubMed1989

Selective diminishment of virus-specific translatable mRNA in the densonucleosis virus-infected midgut of the silkworm, Bombyx mori, reared at a supraoptimal temperature.

Effect of a supraoptimal temperature on the accumulation of virus-specific translatable mRNAs was examined in the larvae of the silkworm. Bombyx mori, infected with Bombyx densonucleosis virus type 2. The results showed that incubation of infected larvae at 35 degrees C resulted in a rapid and selective decrease in the virus-specific translatable mRNAs which preexisted in the infected midgut. Upon temperature-shift from 35 degrees to 25 degrees C, the virus-specific translatable mRNAs became clearly observed within 12 hr. These results indicate that a supraoptimal temperature restricts the accumulation of virus-specific translatable mRNAs. Both rapid decay and suppressed synthesis might be responsible for the selective restriction of virus-specific translatable mRNA accumulation at a supraoptimal temperature.

Animals↗
PubMed1977

The properties of two recent isolates of cytoplasmic polyhedrosis viruses.

Cytoplasmic polyhedrosis viruses (CPVs) were isolated from laboratory cultures of Bombyx mori and Spodoptera exempta. The electrophoretic profile of the RNA segments of both viruses showed similarities with that of type 1 CPV. However, whereas the virus isolate from B. mori appeared identical to type 1 CPV (as assessed by serology, as well as the comparative mobilities of RNA segments and structural polypeptides), the isolate from S. exempta was distinct. Three of the ten viral RNA segments did not co-run with type 1 RNA, and the structural polypeptides of polyhedra had different molecular weights. It is proposed that the S. exempta isolate be included as a new 'type' (type 12) in a classification of these viruses.

Antigens, Viral↗
PubMed1976

The effects of inhibitors of nucleic acid and protein synthesis on the replication of Spodoptera frugiperda nuclear polyhedrosis virus in cultured Spodoptera frugiperda cells.

The effects of inhibitors of nucleic acid and protein synthesis on the replication of Spodoptera frugiperda nuclear polyhedrosis virus have been determined. Two inhibitors of protein synthesis-cycloheximide and puromycin-were irreversible inhibitors of virus multiplication. Three inhibitors of nucleic acid synthesis-actinomycin D, cytosine arabinoside and camptothecin- prevented virus multiplication; only camptothecin was reversible. Rifampicin had no effect on virus multiplication.

Camptothecin↗
PubMed1980

[Pathohistological and ultrastructural studies of the nuclear polyhedrosis virus in the silkworm (Bombyx mori L.)].

Histopathologic studies were carried out on fifth instar silkworm moths of the Super 1 x Super 2 hybrid infected orally with Baculovirus bombycis along with ultrastructural investigations of the pathogen itself. It was found that the earliest changes in the moths set in at the 60th hour post inoculation. They consisted in the aggregation of chromatin, and the formation of polyhedral bodies in the fatty body, hypodermis, and peritracheal matrix; these appeared in the glandular tissue too, but not earlier than the 120th hour, while in the hemolymph they were found at the 40th hour. The morphogenesis of the virus was followed up via the electron microscope, giving a description of its structure. It was found to replicate in the viral plasma formed in the nuclei of the infected cells. First the nucleocapsids emerged which were enveloped in a two layer outer (developing) membrane while they were in the viral plasma or in the space between it and the nuclear membrane (the so-called ring zone). Then these tended to thoroughly enter the ring zone and incorporate randomly into the polyhedral bodies. The virions were enveloped at the rate of one in the developing membrane, rarely being up to five per envelope. It was assumed that both at induction and at artificial infection the process, resp., the virus replication runs its course after one and the same pattern. However, the number of virions in the developing membrane depends on the tissue in whose cells the virus is replicated.

Animals↗
PubMed1998

Improvement of the print-capture polymerase chain reaction procedure for efficient amplification of DNA virus genomes from plants and insect vectors.

A rapid and simple procedure is described to amplify efficiently geminivirus DNA genomes by improving the print-capture polymerase chain reaction (PCR) procedure reported recently for RNA viruses. This method, termed print-PCR (P-PCR), allows direct amplification of DNA from infected plant or whitefly tissues printed directly on Whatman 3MM paper, without the need of any grinding, incubation, or washing steps previous to the amplification reaction. P-PCR reduces sample manipulation and avoids previous extraction of nucleic acids, thereby diminishing the possibilities of cross-contamination between samples. P-PCR has been successfully applied to whiteflies and various plant species infected by two different tomato yellow leaf curl viruses, TYLCV-Sr and TYLCV-Is, and for the amplification of the full-length genome of TYLCV-Is from infected plants.

Animals↗
PubMed1991

Processing, secretion, and immunoreactivity of carboxy terminally truncated dengue-2 virus envelope proteins expressed in insect cells by recombinant baculoviruses.

Two recombinant baculoviruses were constructed by inserting via the transfer vector pAcYM1 the genes coding for the structural proteins of dengue (DEN)-2 virus downstream from the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus. The two recombinants differed in truncation of 26 and 71 amino acids, respectively, in the carboxy-terminal sequence of DEN-specific envelope (E) glycoprotein. Recombinant DEN-2 E glycoproteins were processed and transported to the surface of Spodoptera frugiperda Sf9 cells infected with both viruses. We show that about one-third of the E glycoprotein minus its whole C-terminal hydrophobic anchor domain was secreted into an endoglycosidase H-resistant form. The type-specific neutralizing epitopes were conserved in the recombinant proteins as shown with a panel of monoclonal antibodies.

Animals↗
PubMed1987

Expression of biologically active and antigenically authentic parainfluenza type 3 virus hemagglutinin-neuraminidase glycoprotein by a recombinant baculovirus.

The hemagglutinin-neuraminidase (HN) gene of human type 3 parainfluenza virus has been inserted into a baculovirus expression vector under the control of the polyhedrin promoter. HN protein produced in insect cells by the recombinant baculovirus appeared to be glycosylated, was transported to the cell surface, and was biologically active. All of the HN epitopes previously mapped functionally to a region(s) involved in neuraminidase and/or hemagglutination activities were conformationally unaltered on the recombinant protein. The HN produced in this system also induced a protective immune response in immunized cotton rats. From these studies we conclude that the HN expressed in insect cells represents a source of authentic HN glycoprotein suitable for structural analysis and immunization.

Animals↗
PubMed2005

Immunoreactivity of HCV/HBV epitopes displayed in an epitope-presenting system.

It has been demonstrated that the immunodominant region of the HCV core protein and the hepatitis B surface antigen (HBsAg) have high degree of reactivity. In order to construct a chimeric protein that carries HCV and HBV epitopes and possesses immunogenicity to both HCV and HBV, four epitopes derived from residues aa2-21 (epitope C1), aa22-40 (epitope C2) of the core protein, residues aa315-328 (epitope E) of E1 protein of HCV, and residues aa124-147 (epitope S) of HBsAg were chosen to be displayed in a conformation-specific manner on the outer surface of the Flock House virus capsid protein and expressed in E. coli cells. The reactivity of these epitopes with antisera from hepatitis C and hepatitis B patients and induction of immune response in guinea pigs were determined. The results showed that when displayed in this system, the chimeric protein carrying only epitope S could react with anti-HBsAg positive human sera, elicit an anti-HBsAg response in guinea pigs. The chimeric protein carrying epitopes C1, C2 and E could react with antibodies to different HCV genotypes, elicit an anti-HCV response in guinea pigs. The chimeric protein carrying epitopes C1, C2, E, and S could react with antibodies against HCV and HBV, elicit anti-HCV and anti-HBsAg responses in guinea pigs. The results suggested that these epitopes displayed in this form could be considered for development of epitope-based vaccines against HCV/HBV infections.

Amino Acid Sequence↗
PubMed2006

Identification of transmembrane domain of a membrane associated protein NS5 of Dendrolimus punctatus cytoplasmic polyhedrosis virus.

We examined the intracellular localization of NS5 protein of Dendrolimus punctatus cytoplasmic polyhedrosis virus (DpCPV) by expressing NS5-GFP fusion protein and proteins from deletion mutants of NS5 in baculovirus recombinant infected insect Spodoptera frugiperda (Sf-9) cells. It was found that the NS5 protein was present at the plasma membrane of the cells, and that the N-terminal portion of the protein played a key role in the localization. A transmembrane region was identified to be present in the N-terminal portion of the protein, and the detailed transmembrane domain (SQIHMVWVKSGLVFF, 57-71aa) of N-terminal portion of NS5 was further determined, which was accorded with the predicted results, these findings suggested that NS5 might have an important function in viral life cycle.

Animals↗
PubMed2002

Evidence for insect transmission of rabbit haemorrhagic disease virus.

The spread of rabbit haemorrhagic disease (RHD) virus from quarantine on Wardang Island to mainland Australia in 1995 suggested that insects could be potential vectors. Field observations and laboratory experiments were conducted to address aspects of this hypothesis. Firstly, the variation in insect populations on the island during the field trials was examined. There was approximately a 1,000-fold increase in the number of bushflies, Musca vetustissima, shortly before the spread of the virus. Secondly, M. vetustissima were tested in the laboratory as potential vectors of RHD virus, and it was demonstrated that disease could be transmitted between rabbits by flies. Finally, 13 of 16 insect samples, collected from Wardang Island and from several sites on the mainland following the spread of virus off the island, were positive for the presence of RHD virus by a specific polymerase chain reaction (PCR). Only one sample contained sufficient infectious virus to kill a susceptible rabbit. These data, combined with previously published information on fly biology, suggested that flies, particularly bushflies, may be involved in the transmission of RHD virus. Other possible routes of spread were not assessed in this study.

Animals↗