Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Insect Viruses”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1992

Evidence that the packaging signal for nodaviral RNA2 is a bulged stem-loop.

Flock house virus is an insect virus belonging to the family Nodaviridae; members of this family are characterized by a small bipartite positive-stranded RNA genome. The larger genomic segment, RNA1, encodes viral replication proteins, whereas the smaller one, RNA2, encodes coat protein. Both RNAs are packaged in a single particle. A defective-interfering RNA (DI-634), isolated from a line of Drosophila cells persistently infected with Flock house virus, was used to show that a 32-base region of RNA2 (bases 186-217) is required for packaging into virions. RNA folding analysis predicted that this region forms a stem-loop structure with a 5-base loop and a 13-base-pair bulged stem.

Base Sequence↗
PubMed2000

Nucleotide sequence analysis of Triatoma virus shows that it is a member of a novel group of insect RNA viruses.

Triatoma virus (TrV) is the only virus described to date that infects triatomines, and has previously been considered to be a member of the family Picornaviridae on the basis of physico-chemical properties. The genome of TrV was sequenced completely (9010 nt). Analysis of the sequence revealed the presence of two large open reading frames (ORFs). The predicted amino acid sequence of ORF1 (nt 549-5936) showed significant similarity to the non-structural proteins of several animal and plant RNA viruses. This ORF product contains sequence motifs characteristic of RNA-dependent RNA polymerases (RdRp), cysteine proteases and RNA helicases. ORF1 is preceded by 548 nucleotides of non-coding RNA and the two ORFs are separated by 172 nucleotides of non-coding RNA. Direct N terminus sequence analysis of two capsid proteins showed that ORF2 (nt 6109-8715) encodes the structural proteins of TrV. The predicted amino acid sequence of ORF2 is very similar to the corresponding regions of Drosophila C virus, Plautia stali intestine virus, Rhopalosiphum padi virus and Himetobi P virus and to a partial sequence from the 3' end of the cricket paralysis virus genome. All of these viruses have a novel genome organization and it has been proposed that they are not members of the Picornaviridae, as previously thought, but belong to a new virus family. On the basis of similarities of genome organization, we propose that TrV also belongs to this new virus family.

Amino Acid Sequence↗
PubMed2003

Iridovirus infection of cell cultures from the Diaprepes root weevil, Diaprepes abbreviatus.

We here report the development and viral infection of a Diaprepes root weevil cell culture. Embryonic tissues of the root weevil were used to establish cell cultures for use in screening viral pathogens as potential biological control agents. Tissues were seeded into a prepared solution of insect medium and kept at a temperature of 24 degrees C. The cell culture had primarily fibroblast-like morphology with some epithelial monolayers. Root weevil cells were successfully infected in vitro with a known insect virus, Invertebrate Iridescent Virus 6. Potential uses of insect cell cultures and insect viruses are discussed.

Animals↗
PubMed1994

Identification of the primary structure and the coding capacity of the genome of insect iridescent virus type 6 between the genome coordinates 0.310 and 0.347 (7990 bp).

The primary structure and the coding capacity of the insect iridescent virus type 6--Chilo iridescent virus (CIV)--were determined between the genome coordinates 0.310 (EcoRI site) and 0.347 (ClaI site). The EcoRI CIV DNA fragment M (7.1 kb; 0.310-0.345 map units) harbors one out of at least six loci of DNA replication origins which is located at nucleotide position 485-513. The identification of the structural properties and the coding capacity of the EcoRI CIV DNA fragment M was carried out by DNA nucleotide sequencing, computer-aided sequence analysis and DNA/RNA hybridization. The EcoRI CIV DNA fragment M (7,099 bp; 71.14% A+T and 28.86% G+C) possesses two clusters of five tandemly organized repetitive DNA elements with complex structural arrangements (R1-R5) which are located between nucleotide positions 3272-3350 and 3403-3414. The analysis of the DNA sequences of the EcoRI CIV DNA fragment M revealed the presence of six open reading frames (ORFs 1-6). Two out of six detected putative proteins are of particular interest. ORF-2 was found to be terminated at nucleotide position 366 (TAA) within the DNA sequence of the EcoRI CIV DNA fragment L (0.345-0.381 map units; 7.4 kb). The analysis of ORF-2 (1,051 amino acids; 120 kD) revealed homologies to several DNA-directed RNA polymerases. ORF-6 encodes a protein (606 amino acids; 69 kD) which is related to a group of yeast, Drosophila and mammalian proteins of a distinct family of putative DNA and/or RNA helicases belonging to the 'DEAD/H' superfamily. The transcriptional activity of the EcoRI CIV DNA fragment M was determined by DNA/RNA hybridization experiments. These analyses revealed the existence of three RNA transcripts of about 3.4 kb (t1), 1.8 kb (t2) and 1.2 kb (t3) which agree with the predicted size of the expected RNA transcripts from ORF-2 (1,051 amino acids; 3.1 kb) and ORF-6 (606 amino acids; 1.8 kb).

Amino Acid Sequence↗
PubMed1989

Expression of the fusion glycoprotein of human parainfluenza type 3 virus in insect cells by a recombinant baculovirus and analysis of its immunogenic property.

The fusion (F) glycoprotein of human parainfluenza type 3 (PI3) virus was produced in insect cells using a baculovirus expression vector (pAcYM1). The recombinant glycoprotein was identified by its reactivity with specific monoclonal and polyclonal antibodies and showed an apparent molecular mass of 70 kDa. Although the fusion protein was found on the infected cell surface, it did not appear to be proteolytically cleaved to F1 and F2 subunits. Immunization of hamsters with the recombinant protein elicited antibody which neutralized infectivity and blocked fusion of virus-infected cells. The protective response to challenge infection of immunized hamsters was similar to that observed with affinity purified F from PI3 virus (Ray et al., J. Virol. 62, 783-787, 1988).

Animals↗
PubMed1999

Development of insect cell lines: virus susceptibility and applicability to prawn cell culture.

Insect cells have been successfully cultured in vitro as continuous cell lines for over 35 years. The media, culture methodology and conditions have been well resolved such that, for many insects, new cells lines can be routinely developed. Factors that are considered important for developing insect cell cultures are described as well as some of the history that led to the success. One of the major rationales for developing insect cell lines was for the study of insect viruses. This was particularly true for species of Lepidoptera from which over 900 viruses have been reported. Since many species of Lepidoptera are serious agricultural and forestry pests, effects have been made to utilize some of these pathogens as biological pesticides. Cell cultures are important in this endeavor since viruses require a living cell to reproduce. Of the known insect viruses, the most intensely studied have been the baculoviruses. In addition to their potential for controlling insect pests, they also have been used as expression vectors for producing recombinant proteins. Details of some of these experiments are described. Finally, experiences with insect cells are considered in relation to efforts to develop prawn cell cultures.

Animals↗
PubMed2000

Manipulation of wavelength-dependent behaviour of insects: an IPM tool to impede insects and restrict epidemics of insect-borne viruses.

Because of the inability to cure plant virus diseases and the need to protect the environment from toxic pesticides, alternative indirect strategies of disease control are required. In recent decades, virologists have developed non-pesticidal, cultural control practices aimed at reducing the damage caused by these virus diseases by interrupting their epidemiological cycle. Accumulated data on the cues of the host plants and environment associated with visual communication by insect vectors have facilitated the development of cultural practices that interfere with their search, landing and orientation to the crop. This review includes a description of visual cues affecting the phototactic response of insects and cultural practices developed to protect crops from insects and insect-borne viruses by disrupting their searching behaviour and response.

Animals↗
PubMed1990

Multistage production of Autographa californica nuclear polyhedrosis virus in insect cell cultures.

The aim of our study was to establish an efficient system for the in vitro production of the insect pathogenic Autographa californica nuclear polyhedrosis virus in a Spodoptera frugiperda cell line. We optimized cultivation conditions for cell proliferation as well as for virus replication in a 1.5 litre stirred tank bioreactor. Cell and virus propagation were found to be optimal at a constant oxygen tension of 40%. In order to provide sufficient nutrients during virus synthesis filtration and perfusion devices were connected to the bioreactor. A virus production procedure in a repeated batch mode by using a two stage bioreactor system is described. Stage I was optimized for cell production and stage II for virus production.

Animals↗
PubMed1988

DNA nucleotide sequence analysis of the PvuII DNA fragment L of the genome of insect iridescent virus type 6 reveals a complex cluster of multiple tandem, overlapping, and interdigitated repetitive DNA elements.

The DNA nucleotide sequence of the PvuII DNA fragment L (0.920 to 0.944 map units (m.u.] of the genome (209 kbp) of insect iridescent virus type 6 was determined. The size of this DNA fragment was 5064 bp with a base composition of 39.79% G + C and 60.21% A + T. The DNA sequence contained many perfect direct repeats of sizes up to 145 bp. In addition to these repetitions, a cluster of four imperfect repetitive DNA elements (R1 to R4) with a complex structural arrangement was detected. R1, R2, and R3 existed in duplicate (two boxes (B] between nucleotide positions 271 and 3466) and their size were as follows: R1-B1/B2 (567/568 bp), R2-B1/B2 (917/931 bp), and R3-B1/B2 (92/88 bp). The R4 repetitive element was found in 12 boxes (between bases 1301 and 4417), which were interrupted at nucleotide positions 1883 to 2236 and 3341 to 3587. These interruptions define three segments (S) harboring boxes B1 to B3 (S1), B4 to B8 (S2), and B9 to B12 (S3). The size of the individual boxes was found to be 239, 233, 107, 244, 222, 242, 242, 148, 240, 242, 242, and 102 bp for R4-B1 to B12, respectively. Five open reading frames (ORFs of 118 to 333 amino acid (AA) residues) were detected. The analysis of the amino acid sequences of the largest ORF revealed that the deduced amino acid sequence of the putative gene product contained two repetitions TR1 (three domains of 50 AA) and TR2 (two domains of 74 AA). Sequences of 43 amino acid residues of ORF 5 (160 to 202 AA) were homologous within the majority of ORFs. A consensus sequence-MANL(X)6 IGSSST(X)6 L(X)1 LGS(X)1 LQISG(X)2 L(X)1 VN- was found in all five ORFs. Although classical canonical and noncanonical transcriptional start signals were detectable, polyadenylation signals were not observed.

Amino Acid Sequence↗
PubMed1999

[Expression and characterization of two outer capsid proteins VP2 and VP5 of bluetongue virus in insect cells].

OBJECTIVE: To study the biological characteristics of the outer capsid proteins VP2 and VP5 of bluetongue virus (BTV) expressed in insect cells and their potential use in the assembly of BTV and genetic engineering vaccine. METHODS: The genes which encode the two outer capsid proteins VP2 and VP5 of bluetongue virus (BTV) 10 were separately cloned into pFastBac1 vector and the corresponding recombinant baculoviruses were obtained. RESULTS: BTV VP2 could be expressed in Sf-9 cells better than VP5. Further works indicated that VP2 could elicit neutralizing antibodies to BTV10(1:64), and also could partially neutralize BTV1(1:16), but could not neutralize BTV13. The co-immunizing of VP2 and VP5 could induce higher neutralizing antibodies to BTV10 and BTV1. VP2 also showed a hemagglutination activity. CONCLUSION: VP2 expressed in insect cells could induce neutralizing antibodies to BTV and had the biological activity of hemagglutination, VP5 could enhance the ability of neutralizing antibody induction of VP2, they can be used for the assembly of virus-like particles and for the development of genetic engineering vaccine.

Animals↗
PubMed1994

Purification of recombinant 38-kDa phosphorylated protein of Marek's disease virus from insect cells through an affinity column.

The 38-kDa phosphorylated protein (pp38) of Marek's disease virus (MDV) expressed in insect cell line Sf9 cells infected with recombinant baculovirus BP38II was purified through an affinity column made of CNBr-Sepharose 4B linked with monoclonal antibody (Mab) H19 specific to serotype I MDV. The result of SDS-PAGE showed a main band of 38 kDa in the lane loaded with the purified pp38, and this band was specifically recognized by MAb H19 in Western blot. The serum from mice immunized with the purified recombinant pp38 reacted only to Sf9 cells infected with the recombinant baculovirus BP38II but not with wild baculovirus. It also gave a titer of 1:128 in indirect fluorescence antibody test to MDV-infected chick embryo fibroblast cells. These results indicated that the purification procedure was effective and that it would be useful for investigating the biological functions of MDV pp38.

Animals↗
PubMed1994

Expression of recombinant E2 and C proteins of rubella virus in insect cells.

We have constructed a recombinant baculovirus expressing the rubella virus E2 (42-45 KDa) and C (34 KDa) proteins. Sf9 cells infected with recombinant virus were able to synthesize and process the two proteins coded by a unique precursor gene. By immunoblot and immunoprecipitation analysis with polyclonal and monoclonal antibodies, a precursor polyprotein (66 KDa) and two other proteins migrating with an apparent molecular weight of 42 KDa and 36 KDa were recognized as E2 glycoprotein and C protein, respectively. The recombinant E2 protein appeared to be glycosylated since it was susceptible to tunicamycin. The results indicate that the RV polyprotein coding for E2 and C is expressed and proteolytically cleaved in insect cells. This baculovirus expression system provides a useful alternative approach for the production of rubella virus antigens and should allow the purification of large quantities of the RV proteins for further biochemical and immunological studies.

Animals↗