1.Field Trials of CpGV Virus Isolates Overcoming Resistance to CpGV-M
M. BERLING ; J.b. REY ; S.j. ONDET ; Y. TALLOT ; O. SOUBABèRE ; A. BONHOMME ; B. SAUPHANOR ; M. LOPEZFERBER
Virologica Sinica 2009;24(5):470-477
The Cydia pomonella granulovirus (CpGV) has been used for many years as biological agent for codling moth control in apple orchards. Resistance to the Mexican strain of CpGV was detected in orchards in Germany, France and Italy. A laboratory insect colony was started from insects collected in a French resistant orchard. It was named RGV. Various virus isolates were identified as active against this resistant insect colony. Field tests were carried out in 2007 to test if the two virus isolates CpGV-I12 and NPP-R1 were effective in the field. Although these virus isolates were not able to reduce insect caused fruit damages, they significantly reduced the overwintering insect populations. NPP-R1 was subjected to eight passages on RGV larvae (NPP-R1.8) that improved its biological activity on RGV larvae. 2008 field trials were set up to test this improved virus strain, compared to CpGV-I12 and Madex plus active on RGV. These tests confirmed the ability to control both in susceptible and resistant insect populations.
2.Specificity of Developmental Resistance in Gypsy Moth (Lymantria dispar) to two DNA-Insect Viruses
Virologica Sinica 2009;24(5):493-500
Gypsy moth (Lymantria dispar) larvae displayed marked developmental resistance within an instar to L. dispar M nucleopolyhedrovirus (LdMNPV) regardless of the route of infection (oral or intrahemocoelic) in a previous study, indicating that in gypsy moth, this resistance has a systemic component.In this study, gypsy moth larvae challenged with the Amsacta moorei entomopoxvirus (AMEV) showed developmental resistance within the fourth instar to oral, but not intrahemocoelic, inoculation. In general, gypsy moth is considered refractory to oral challenge with AMEV, but in this study, 43% mortality occurred in newly molted fourth instars fed a dose of 5×106 large spheroids of AMEV; large spheroids were found to be more infectious than small spheroids when separated by a sucrose gradient. Developmental resistance within the fourth instar was reflected by a 2-fold reduction in mortality (18%-21%) with 5×106 large spheroids in larvae orally challenged at 24, 48 or 72 h post-molt. Fourth instars were highly sensitive to intrahemocoelic challenge with AMEV; 1PFU produced approximately 80% mortality regardless of age within the instar. These results indicate that in gypsy moth, systemic developmental resistance may be specific to LdMNPV, reflecting a co-evolutionary relationship between the baculovirus and its host.
3.Global Transcriptional Profile of Tranosema rostrale lchnovirus Genes in Infected Lepidopteran Hosts and Wasp Ovaries
Asieh RASOOLIZADEH ; Frédéric DALLAIRE ; Don STEWART ; Catherine BéLIVEAU ; Renée LAPOINTE ; Michel CUSSON
Virologica Sinica 2009;24(5):478-492
The ichnovirus TrIV, transmitted by the endoparasitic wasp Tranosema rostrale to its lepidopteran host during oviposition, replicates asymptomatically in wasp ovaries and causes physiological dysfunctions in parasitized caterpillars. The need to identify ichnoviral genes responsible for disturbances induced in lepidopteran hosts has provided the impetus for the sequencing and annotation of ichnovirus genomes, including that of TrIV. In the latter, 86 putative genes were identified, including 35 that could be assigned to recognized ichnoviral gene families. With the aim of assessing the relative importance of each TrIV gene, as inferred from its level of expression, and evaluating the accuracy of the gene predictions made during genome annotation, the present study builds on an earlier qPCR quantification of transcript abundance of TrIV rep ORFs, in both lepidopteran and wasp hosts, extending it to other gene families as well as to a sample of unassigned ORFs. We show that the majority (91%) of putative ORFs assigned to known gene families are expressed in infected larvae, while this proportion is lower (67%) for a sample taken among the remaining ORFs. Selected members of the TrV and rep gene families are shown to be transcribed in infected larvae at much higher levels than genes from any other TrIV gene family, pointing to their likely involvement in host subjugation. In wasp ovaries, the transcriptional profile is dominated by a rep gene and a member of a newly described gene family encoding secreted proteins displaying a novel cysteine motif, which we identified among previously unassigned ORFs.
4.Biological Control of Tortricidae in Tea Fields in Japan Using Insect Viruses and Parasitoids
Virologica Sinica 2009;24(4):323-332
Tea is a perennial and evergreen plant. Cultivated tea trees provide a habitat for insect pests and their natural enemies. In Japan, granuloviruses (GVs) have successfully controlled two of the most important pests of tea, Adoxophyes honmai and Homona magnanima (Tortricidae: Lepidoptera). The GVs are produced in vivo and a single application sustains pesticidal efficacy throughout a year, which encompasses 4 to 5 discrete generations of both species. A. honmai and H. magnanima also have various natural enemies, especially hymenopteran parasitoids. Such resident natural enemies also play a role in reducing the pest density in virus-controlled fields, but the effect of virus infection on parasitoids sharing the same host larva has not been well studied. Survival of one of the major parasitoids ofA. honmai, Ascogaster reticulata (Braconidae: Hymenoptera), is reduced by virus infection of the host. Viruses, including GV and entomopoxvirus (EPV), and certain koinobiont endoparasitoids, including A. reticulata, are both known to regulate host endocrinology. However, the GV and EPV have distinct host regulation mechanisms, and consequently have different impacts on the survival of A. retuculata, when A. reticulata parasitizes a host that is infected with either GV or EPV. These additional effects on host regulation displayed by both viruses and parasitoids affect the outcome of virus-parasitoid interactions.
5.Molecular Dissection of Bombyx mori Nucleopolyhedrovirus orf8 Gene
Virologica Sinica 2009;24(4):315-322
Viruses including baculoviruses are obligatory parasites, as their genomes do not encode all the proteins required for replication. Therefore, viruses have evolved to exploit the behavior and the physiology of their hosts and often eoevolved with their hosts over millions of years. Recent comparative analyses of complete genome sequences of baculoviruses revealed the patterns of gene acquisitions and losses that have occurred during baculovirus evolution. In addition, knowledge of virus genes has also provided understanding of the mechanism of baculovirus infection including replication, species-specific virulence and host range. The Bm8 gene of Bombyx mori nucleopolyhedrovirus (NPV) and its homologues are found only in group I NPV genomes. The Autographa californica NPV Acl6 gene is a homologue of Bm8 and, encodes a viral structural protein. It has been shown that Bm8/Ac 16 interacts with baculoviral and cellular proteins. Bm8/Ac 16 interacts with baculoviral IE1 that is facilitated by coiled coil domains, and the interaction with IE1 is important for Bin8 function. Ac16 also forms a complex with viral FP25 and cellular actin and associates with membranes via palmitoylation. These data suggested that this gene family encodes a multifunctional protein that accomplishes specific needs of group INPVs.
6.Virion Proteomics of Large DNA Viruses
Ranran WANG ; Zhihong HU ; Hualin WANG ; Fei DENG
Virologica Sinica 2009;24(4):268-284
Large DNA viruses normally have complex structures with many of protein components derived from both viral and host origins. The development in proteomics, especially mass spectrometry identification techniques provide powerful tools for analyzing large viruses. In this review, we have summarized the recent achievements on proteomic studies of large DNA viruses, such as herpesvirus, poxvirus, nimavirus and baculoviruse. The proteomics of baculovirus occlusion-derived virions (ODV) were emphasized. Different mass spectrometry techniques used on ,carious baculoviruses were introduced, and the identified structurally associated proteins of baculoviruses are summarized.
7.Genetic Analysis of the VP1 Region of Human Enterovirus 71 Strains Isolated in Fuyang, China, During 2008
Shaohui MA ; Jiansheng LIU ; Jingjing WANG ; Haijing SHI ; Huijuan YANG ; Junying CHEN ; Longding LIU ; Qihan LI
Virologica Sinica 2009;24(3):162-170
Enterovirus 71 (EV71) is a common cause of Hand, foot, and mouth disease (HFMD) and may also cause severe neurological diseases, such as encephalitis and poliomyelitis-like paralysis. To examine the genetic diversity of EV71, we determined and analyzed the complete VP1 sequences (891 nucleotides) from nine EV71 strains isolated in Fuyang, China. We found that nine EV71 strains isolated were over 98% homologous at the nucleotide level and 93%-100% homologous to members of the C4 subgenogroup. At the amino acid level, these Fuyang strains were 99% -100% homologous to one another, 97%-100% homologous to members of the C4 subgenogroup, and the histidine(H) at amino acid position 22 was conserved among the Fuyang strains. The results indicate that Fuyang isolates belong to genotype C4, and an H at position 22 appears to be a marker for the Fuyang strains.
8.Genetic Variation Analyses of nsp2 Gene of PRRSV in Ningxia Hui Autonomous Region of China
Hong TIAN ; Jingyan WU ; Shuanghui YIN ; Youjun SHANG ; Ziping MAN ; Na ZHAO ; Ye JIN ; Xiangtao LIU
Virologica Sinica 2009;24(3):221-226
To gain a better understanding of the genetic diversity and evolution of PRRSV in the Ningxia Hui Nationality Autonomous Region (Ningxia) of China, the nsp2 genes from a series of PRRSV strains collected from the region in 2007 were partially sequenced. These sequences were then analyzed along with the classical strain (ch-la) and two other epidemic strains SD (3) and SD2006. Comparison of the nucleotide sequence with ch-la indicated that nsp2 genes of seventeen Ningxia isolates (NX strain) have deletions of 87 nucleotides. Sequence analysis indicated that homology between the Ningxia strain and ch-la was 60.3%-79.9% in the nucleotide sequence, and homology between the NX strains and SD strains was 80.3%-98.8% in the nucleotide sequence. The nsp2 genes of the seventeen isolates had 74.9%-100% nucleotide sequence identities with each other. This study was undertaken to assess the regional variation of prevalent PRRSV and to establish a sequence database for PRRSV molecular epidemiological studies.
9.Application of VP1 Protein to Develop Monoclonal Antibody against Foot-and-mouth Disease Virus Asial Type
Tong LIN ; Junzheng DU ; Junjun SHAO ; Guozheng CONG ; Shuai SONG ; Shandian GAO ; Huiyun CHANG
Virologica Sinica 2009;24(3):215-220
In order to develop an anti-FMDV Asial type monoclonal antibody (mAb), BABL/c mice were immunized with recombinant FMDV VP1 protein. Three mAbs, 1B8, 5E1 and 5E2, were then further optimized. The result indicated that prepared anti-FMDV Asial mAbs had no cross-reactivity with Swine vesicular disease (SVD) and FMDV O, A and C type antigen. Their titers in abdomen liquor were l:5×106, l:2×106 and l:5×l06, respectively. 1B8 was found to be of IgGi subtype, 5E1 and 5E2 belonged to IgG2b subtype. In this study, the prepared mAbs are specific for detecting FMDV type Asial, and is potentially useful for pen-side diagnosis.
10.HCMV Infection Depress NGF Expression in Human Glioma Cells
Haitao WANG ; Bin WANG ; Zhijun LIU ; Zhiqiang BAI ; Ling LI ; Dongmeng QIAN ; Zhiyong YAN ; Xuxia SONG
Virologica Sinica 2009;24(3):209-214
Human cytomegalovirus (HCMV) is the most common cause of congenital infection, resulting in birth defects such as microcephaly. In this study, RT-PCR and Western Blotting were performed to quantify the regulation of endogenic nerve growth factor expression in neuroglia cells by HCMV infection. The results showed that basal, endogenous NGF expression in U251 was unchanged during early HCMV infection. NGF expression is strongly down-regulated during the latent phase of infection. These results suggest that HCMV can depress the NGF expression in U251 cells.