Isolation,Replication and Polyhedrin Gene Sequence of an Israeli Helicoverpa Armigera Single Nucleopolyhedrovirus

A local strain of Helicoverpa armigera baculovirus was isolated from infected H. armigera larvae. Infectivity to Helicoverpa cells, restriction enzyme analysis and electron microscopy allowed its identification as a single embedded nucleopolyhedrovirus, designated HaSNPV-IS. Analysis of DNA replication, protein synthesis and polyhedrin expression in HaSNPV-infected cells located the late and very late phases of the viral cycle at 24 and 48 h after infection, respectively. The viral polyhedrin gene was isolated and characterized. It encoded for a polypeptide of 246 amino acid residues. A 32 kDa polypeptide was identified by immunoblot analysis using anti-polyhedrin antiserum. The HaSNPV-IS polyhedrin DNA sequence revealed 99.4% of homology to the HzSNPV polyhedrin. The availability of this efficient replication system and the above knowledge paves the way to future genetic engineering of the HaSNPV. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification and Classification of the Spodoptera littoralis Nucleopolyhedrovirus Inhibitor of Apoptosis Gene

Baculoviruses possess two types of genes that suppressed apoptosis, p35 and inhibitor of apoptosis (iap). In this study we report the isolation and identification of an inhibitor of apoptosis gene Sliap in the genome of the Spodoptera littoralis nucleopolyhedrovirus (SlNPV). The Sliap sequence predicted a 15 kDa polypeptide with only one BIR domain and a RING finger, both motifs characteristic of the IAP family of proteins, and a third specific acidic-rich motif. These characteristics, shared with the Spodoptera littura NPV IAP2/3, Epiphyas postvittana NPV IAP4, Lymantria dispar NPV IAP and Orgyia pseudotsugata NPV IAP4 (Orf 107) allowed us to classify them in a new homology group (IAP-4). Sliap was able to delay, but not to suppress, apoptosis induced by replication of a recombinant AcMNPV deficient in p35. In SlNPV infected-SF9 cells Sliap was expressed earlier than sl-p49 suggesting that its role at the initiation of infection was to delay the apoptotic response of the host.     

Selective inhibition of herpes simplex virus type 1 DNA polymerase by zinc ions.

The DNA polymerase of herpes simplex virus (HSV) was isolated from nuclei of infected BSC-1 cells by centrifugation in sucrose gradients and by chromatography on double-stranded DNA cellulose columns. The viral enzyme was almost completely inhibited in vitro by 0.1 mM zinc acetate. The a and β cellular DNA polymerases were resistant to 0.3 mM zinc acetate when tested under in vitro conditions. Inhibition of HSV replication can be explained by the selective inhibitory effect of zinc ions on the viral DNA polymerase.     

Replication of Varroa destructor virus 1 (VDV-1) and a Varroa destructor virus 1-deformed wing virus recombinant (VDV-1-DWV) in the head of the honey bee

A country-wide screen for viral pathogens in Israeli apiaries revealed significant incidence of deformed wing virus (DWV) and Varroa destructor-1 virus (VDV-1). To understand these viruses' possible involvement in deformed wing syndrome of honey bees, we studied their replication in symptomatically and asymptomatically infected bees qualitatively and quantitatively, using RT-PCR, quantitative real-time RT-PCR, and immunodetection of the major viral capsid protein VP1. We found, for the first time, replication of VDV-1 and/or a VDV-1-DWV recombinant virus in the heads of recently emerged symptomatic bees. These viruses replicated to high copy numbers, yielding the major viral capsid VP1 processed for subsequent assembly of viral particles. Our results clearly distinguished between symptomatic and asymptomatic bees infected with VDV-1 and VDV-1-DWV and suggest the hypothesis that VDV-1, in addition to DWV, may be involved in inducing the deformed wing pathology. Thus VDV-1-DWV recombination may yield virulent strains able to cause overt infections in Varroa-infested bee colonies.     

Deoxyribonucleic Acid Polymerase of Wild-Type and Phosphonoacetic Acid-Resistant Mutant of Herpes Simplex Virus

The phosphonacetic acid (PAA)-susceptible deoxyribonucleic acid (DNA) polymerase of herpes simplex virus type 1 was partially purified and isolated in sucrose gradients and on double-strand DNA cellulose columns. The DNA polymerase isolated from cells infected with the PAA-resistant mutant had the same molecular weight as the wild-type enzyme (140,000 to 149,000) but was consistently more resistant to PAA.     

Metatranscriptome Analysis of Sympatric Bee Species Identifies Bee Virus Variants and a New Virus,Andrena-Associated Bee Virus-1

Bees are important plant pollinators in agricultural and natural ecosystems. High average annual losses of honey bee (Apis mellifera) colonies in some parts of the world, and regional population declines of some mining bee species (Andrena spp.), are attributed to multiple factors including habitat loss, lack of quality forage, insecticide exposure, and pathogens, including viruses. While research has primarily focused on viruses in honey bees, many of these viruses have a broad host range. It is therefore important to apply a community level approach in studying the epidemiology of bee viruses. We utilized high-throughput sequencing to evaluate viral diversity and viral sharing in sympatric, co-foraging bees in the context of habitat type. Variants of four common viruses (i.e., black queen cell virus, deformed wing virus, Lake Sinai virus 2, and Lake Sinai virus NE) were identified in honey bee and mining bee samples, and the high degree of nucleotide identity in the virus consensus sequences obtained from both taxa indicates virus sharing. We discovered a unique bipartite + ssRNA Tombo-like virus, Andrena-associated bee virus-1 (AnBV-1). AnBV-1 infects mining bees, honey bees, and primary honey bee pupal cells maintained in culture. AnBV-1 prevalence and abundance was greater in mining bees than in honey bees. Statistical modeling that examined the roles of ecological factors, including floral diversity and abundance, indicated that AnBV-1 infection prevalence in honey bees was greater in habitats with low floral diversity and abundance, and that interspecific virus transmission is strongly modulated by the floral community in the habitat. These results suggest that land management strategies that aim to enhance floral diversity and abundance may reduce AnBV-1 spread between co-foraging bees.     

Herpes simplex virus DNA polymerase,thymidine kinase and deoxyribonuclease activities in cells infected with wild type,ultraviolet-irradiated and defective virus

Summary The DNA polymerase, thymidine kinase and deoxyribonuclease activities were studied in cells infected with wild type(wt), ultraviolet (UV)-irradiated and defective herpes simplex virus type 1. All three enzymatic activities were expressed in cells infected withwt virus. In cells infected with UV-irradiated virus, the thymidine kinase and deoxyribonuclease activities were inhibited and the DNA polymerase activity was markedly suppressed. In cells producing defective virus, there was thymidine kinase activity, but the viral deoxyribonuclease activity was considerably reduced. The DNA polymerase activity was fully expressed in cells producing defective virus at passage level 5, but at passage level 6, the activity of the viral DNA polymerase declined.With 6 Figures