In vitro host range of Autographa californica nucleopolyhedrovirus recombinants lacking functional p35, iap1 or iap2.

Infection of insect larvae with Autographa californica nucleopolyhedrovirus (AcMNPV) results in the liquefaction of the host, a process involving the action of virus-encoded chitinase and cathepsin gene products. Chitinase is localized in the endoplasmic reticulum (ER) during infection because of the presence of a C-terminal ER retrieval motif (KDEL). In this study, the KDEL coding region was removed from the chitinase gene so that expression of the modified chitinase remained under the control of its own gene promoter, at its native locus. The deletion of KDEL resulted in the redistribution of chitinase within the cell during virus infection. Chitinase lacking the KDEL motif was detectable at the plasma membrane and was also evident in the culture medium of virus-infected cells from as early as 12 h post-infection (p.i.). Secretion of chitinase from the cell continued up to 72 h p.i., until cytolysis. The biological activity of the recombinant virus in Trichoplusia ni larvae was enhanced, with a significant reduction in the lethal dose and lethal time associated with infection. Furthermore, a reduction in feeding damage caused by infected larvae was observed compared to AcMNPV-infected individuals.

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Lymantria dispar Nucleopolyhedrovirushrf-1 Expands the Larval Host Range of Autographa californica Nucleopolyhedrovirus

Journal of Virology ◽

10.1128/jvi.72.3.2526-2531.1998 ◽

1998 ◽

Vol 72 (3) ◽

pp. 2526-2531 ◽

Cited By ~ 31

Author(s):

Chi-Ju Chen ◽

Martha E. Quentin ◽

Lynn A. Brennan ◽

Christine Kukel ◽

Suzanne M. Thiem

Keyword(s):

Host Range ◽

Lymantria Dispar ◽

Helicoverpa Zea ◽

Autographa Californica ◽

Insect Larvae ◽

Resistant Species ◽

Larval Host ◽

Autographa Californica Nucleopolyhedrovirus ◽

High Doses ◽

Third Instar Larvae

The gypsy moth (Lymantria dispar) is nonpermissive forAutographa californica nucleopolyhedrovirus (AcNPV) infection. We previously isolated a gene, host range factor 1 (hrf-1), from L. dispar nucleopolyhedrovirus that promotes AcNPV replication in Ld652Y cells, a nonpermissiveL. dispar cell line (S. M. Thiem, X. Du, M. E. Quentin, and M. M. Berner, J. Virol. 70:2221–2229, 1996). In the present study, we investigated the ability of hrf-1 to alter the larval host range of AcNPV. Bioassays using recombinant AcNPV bearing hrf-1 were conducted with insect larvae by use of oral infection. AcNPV bearing hrf-1 was infectious for neonate L. dispar larvae, with a 50% lethal concentration of 1.2 × 105 polyhedral inclusion bodies/ml of diet, which is similar to that of wild-type AcNPV for permissive hosts. AcNPV can kill neonate L. dispar larvae at high doses, but it does not kill third-instar larvae. However, electron microscopy studies of AcNPV-inoculated third-instar larvae revealed virus replication in the midgut cells. PCR analyses indicated that the virus was AcNPV. These results suggest that the block for AcNPV infection of L. dispar larvae is its inability to spread systematically from primary infection sites in the midgut epithelium and that this barrier is leaky in neonates. hrf-1 allows AcNPV to overcome this barrier. AcNPV recombinants bearing hrf-1 were also significantly more infectious for Helicoverpa zea, a resistant species, suggesting that the blocks for AcNPV infection ofL. dispar and H. zea larvae may be similar.

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Revealing biophysical properties of KfrA-type proteins as a novel class of cytoskeletal, coiled-coil plasmid-encoded proteins

BMC Microbiology ◽

10.1186/s12866-020-02079-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

M. Adamczyk ◽

E. Lewicka ◽

R. Szatkowska ◽

H. Nieznanska ◽

J. Ludwiczak ◽

...

Keyword(s):

Dna Binding ◽

Host Range ◽

Coiled Coil ◽

Amino Acid Sequences ◽

Broad Host Range ◽

Biophysical Properties ◽

Dna Binding Sites ◽

In Silico Studies ◽

Wide Range

Abstract Background DNA binding KfrA-type proteins of broad-host-range bacterial plasmids belonging to IncP-1 and IncU incompatibility groups are characterized by globular N-terminal head domains and long alpha-helical coiled-coil tails. They have been shown to act as transcriptional auto-regulators. Results This study was focused on two members of the growing family of KfrA-type proteins encoded by the broad-host-range plasmids, R751 of IncP-1β and RA3 of IncU groups. Comparative in vitro and in silico studies on KfrAR751 and KfrARA3 confirmed their similar biophysical properties despite low conservation of the amino acid sequences. They form a wide range of oligomeric forms in vitro and, in the presence of their cognate DNA binding sites, they polymerize into the higher order filaments visualized as “threads” by negative staining electron microscopy. The studies revealed also temperature-dependent changes in the coiled-coil segment of KfrA proteins that is involved in the stabilization of dimers required for DNA interactions. Conclusion KfrAR751 and KfrARA3 are structural homologues. We postulate that KfrA type proteins have moonlighting activity. They not only act as transcriptional auto-regulators but form cytoskeletal structures, which might facilitate plasmid DNA delivery and positioning in the cells before cell division, involving thermal energy.

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Investigation of Salmonella Phage–Bacteria Infection Profiles: Network Structure Reveals a Gradient of Target-Range from Generalist to Specialist Phage Clones in Nested Subsets

Viruses ◽

10.3390/v13071261 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1261

Author(s):

Khatuna Makalatia ◽

Elene Kakabadze ◽

Nata Bakuradze ◽

Nino Grdzelishvili ◽

Ben Stamp ◽

...

Keyword(s):

Host Range ◽

Salmonella Enterica ◽

Target Range ◽

Nested Subsets ◽

Specific Phage ◽

Salmonella Infections ◽

Specialist Species ◽

Host Infection ◽

Salmonella Phage

Bacteriophages that lyse Salmonella enterica are potential tools to target and control Salmonella infections. Investigating the host range of Salmonella phages is a key to understand their impact on bacterial ecology, coevolution and inform their use in intervention strategies. Virus–host infection networks have been used to characterize the “predator–prey” interactions between phages and bacteria and provide insights into host range and specificity. Here, we characterize the target-range and infection profiles of 13 Salmonella phage clones against a diverse set of 141 Salmonella strains. The environmental source and taxonomy contributed to the observed infection profiles, and genetically proximal phages shared similar infection profiles. Using in vitro infection data, we analyzed the structure of the Salmonella phage–bacteria infection network. The network has a non-random nested organization and weak modularity suggesting a gradient of target-range from generalist to specialist species with nested subsets, which are also observed within and across the different phage infection profile groups. Our results have implications for our understanding of the coevolutionary mechanisms shaping the ecological interactions between Salmonella phages and their bacterial hosts and can inform strategies for targeting Salmonella enterica with specific phage preparations.

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A Functional F Analogue of Autographa californica Nucleopolyhedrovirus GP64 from the Agrotis segetum Granulovirus

Journal of Virology ◽

10.1128/jvi.00493-08 ◽

2008 ◽

Vol 82 (17) ◽

pp. 8922-8926 ◽

Cited By ~ 18

Author(s):

Feifei Yin ◽

Manli Wang ◽

Ying Tan ◽

Fei Deng ◽

Just M. Vlak ◽

...

Keyword(s):

Fusion Protein ◽

Membrane Fusion ◽

Plutella Xylostella ◽

Syncytium Formation ◽

Low Ph ◽

Autographa Californica ◽

Agrotis Segetum ◽

Induced Membrane ◽

F Protein ◽

Autographa Californica Nucleopolyhedrovirus

ABSTRACT The envelope fusion protein F of Plutella xylostella granulovirus is a computational analogue of the GP64 envelope fusion protein of Autographa californica nucleopolyhedrovirus (AcMNPV). Granulovirus (GV) F proteins were thought to be unable to functionally replace GP64 in the AcMNPV pseudotyping system. In the present study the F protein of Agrotis segetum GV (AgseGV) was identified experimentally as the first functional GP64 analogue from GVs. AgseF can rescue virion propagation and infectivity of gp64-null AcMNPV. The AgseF-pseudotyped AcMNPV also induced syncytium formation as a consequence of low-pH-induced membrane fusion.

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Autographa californica Nucleopolyhedrovirus AC141 (Exon0), a Potential E3 Ubiquitin Ligase, Interacts with Viral Ubiquitin and AC66 To Facilitate Nucleocapsid Egress

Journal of Virology ◽

10.1128/jvi.01713-17 ◽

2017 ◽

Vol 92 (3) ◽

Cited By ~ 4

Author(s):

Siddhartha Biswas ◽

Leslie G. Willis ◽

Minggang Fang ◽

Yingchao Nie ◽

David A. Theilmann

Keyword(s):

Ubiquitin Ligase ◽

Nuclear Export ◽

Molecular Mechanisms ◽

Nuclear Periphery ◽

E3 Ubiquitin Ligase ◽

Autographa Californica ◽

Nucleocapsid Proteins ◽

Systemic Spread ◽

Autographa Californica Nucleopolyhedrovirus ◽

Budded Virus

ABSTRACTDuring the infection cycle of Autographa californica multiple nucleopolyhedrovirus (AcMNPV), two forms of virions are produced, budded virus (BV) and occlusion-derived virus (ODV). Nucleocapsids that form BV have to egress from the nucleus, whereas nucleocapsids that form ODV remain inside the nucleus. The molecular mechanism that determines whether nucleocapsids remain inside or egress from the nucleus is unknown. AC141 (a predicted E3 ubiquitin ligase) and viral ubiquitin (vUbi) have both been shown to be required for efficient BV production. In this study, it was hypothesized that vUbi interacts with AC141, and in addition, that this interaction was required for BV production. Deletion of bothac141andvubirestricted viral infection to a single cell, and BV production was completely eliminated. AC141 was ubiquitinated by either vUbi or cellular Ubi, and this interaction was required for optimal BV production. Nucleocapsids in BV, but not ODV, were shown to be specifically ubiquitinated by vUbi, including a 100-kDa protein, as well as high-molecular-weight conjugates. The viral ubiquitinated 100-kDa BV-specific nucleocapsid protein was identified as AC66, which is known to be required for BV production and was shown by coimmunoprecipitation and mass spectrometry to interact with AC141. Confocal microscopy also showed that AC141, AC66, and vUbi interact at the nuclear periphery. These results suggest that ubiquitination of nucleocapsid proteins by vUbi functions as a signal to determine if a nucleocapsid will egress from the nucleus and form BV or remain in the nucleus to form ODV.IMPORTANCEBaculoviruses produce two types of virions called occlusion-derived virus (ODV) and budded virus (BV). ODVs are required for oral infection, whereas BV enables the systemic spread of virus to all host tissues, which is critical for killing insects. One of the important steps for BV production is the export of nucleocapsids out of the nucleus. This study investigated the molecular mechanisms that enable the selection of nucleocapsids for nuclear export instead of being retained within the nucleus, where they would become ODV. Our data show that ubiquitination, a universal cellular process, specifically tags nucleocapsids of BV, but not those found in ODV, using a virus-encoded ubiquitin (vUbi). Therefore, ubiquitination may be the molecular signal that determines if a nucleocapsid is destined to form a BV, thus ensuring lethal infection of the host.

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Biocontrol of seed-borne Alternaria raphani and A. brassicicola

Canadian Journal of Microbiology ◽

10.1139/m87-149 ◽

1987 ◽

Vol 33 (10) ◽

pp. 850-856 ◽

Cited By ~ 27

Author(s):

G. Vannacci ◽

G. E. Harman

Keyword(s):

Biological Control ◽

Host Range ◽

Trichoderma Harzianum ◽

Pythium Species ◽

Biological Control Agents ◽

Fusarium Sp ◽

Chamber Studies ◽

Growth Chamber Studies ◽

Radish Seedlings

Forty-two microorganisms were tested as biological control agents against Alternaria raphani and A. brassicicola. Tests were conducted for in vitro antagonistic ability, for ability to control the pathogens on naturally infected seeds germinated on moistened blotters, and in planting mix in growth chamber studies, and for their ability to reduce pod infection. The organisms tested were obtained from cruciferous seeds or were strains already identified as being effective against soil-borne Pythium species. The blotter test indicated that six organisms increased both the number of healthy seedlings and the number of seedlings produced from A. raphani infected radish seeds. An additional seven strains improved either germination or increased the number of healthy seedlings. Twenty-nine organisms increased the number of healthy cabbage seedlings from A. brassicicola infected seeds, but total germination was not modified by any treatment. Experiments in planting mix showed that five antagonists (Chaetomium globosum, two strains of Trichoderma harzianum, T. koningii, and Fusarium sp.) increased the number of healthy plants in both radish samples tested, while four additional antagonists provided a significant increase in only one of the samples tested. The five antagonists that consistently increased numbers of healthy radish seedlings also decreased pod infection by A. raphani. None were as effective as iprodrone, however. Several effective antagonists were found to be mycoparasitic against Alternaria spp. Some strains of Trichoderma previously found to be effective against Pythium spp. were also effective against Alternaria spp., indicating that these strains have a wide host range.

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Glycoprotein D-Independent Infectivity of Pseudorabies Virus Results in an Alteration of In Vivo Host Range and Correlates with Mutations in Glycoproteins B and H

Journal of Virology ◽

10.1128/jvi.75.21.10054-10064.2001 ◽

2001 ◽

Vol 75 (21) ◽

pp. 10054-10064 ◽

Cited By ~ 18

Author(s):

Jerg Schmidt ◽

Volker Gerdts ◽

Jörg Beyer ◽

Barbara G. Klupp ◽

Thomas C. Mettenleiter

Keyword(s):

Host Range ◽

Pseudorabies Virus ◽

Natural Host ◽

Target Cells ◽

Glycoprotein D ◽

Wild Type ◽

Cellular Receptors ◽

Receptor Usage

ABSTRACT Infection of cells by herpesviruses is initiated by the interaction of viral envelope glycoproteins with cellular receptors. In the alphaherpesvirus pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, the essential glycoprotein D (gD) mediates secondary attachment of virions to target cells by binding to newly identified cellular receptors (R. J. Geraghty, C. Krummenacher, G. H. Cohen, R. J. Eisenberg, and P. G. Spear, Science 280:1618–1620, 1998). However, in the presence of compensatory mutations, infection can also occur in the absence of gD, as evidenced by the isolation in cell culture of an infectious gD-negative PrV mutant (PrV-gD− Pass) (J. Schmidt, B. G. Klupp, A. Karger, and T. C. Mettenleiter, J. Virol. 71:17–24, 1997). PrV-gD− Pass is replication competent with an only moderate reduction in specific infectivity but appears to bind to receptors different from those recognized by wild-type PrV (A. Karger, J. Schmidt, and T. C. Mettenleiter, J. Virol. 72:7341–7348, 1998). To analyze whether this alteration in receptor usage in vitro influences infection in vivo, the model host mouse and the natural host pig were intranasally infected with PrV-gD− Pass and were compared to animals infected by wild-type PrV. For mice, a comparable progress of disease was observed, and all animals infected with mutant virus died, although they exhibited a slight delay in the onset of symptoms and, correspondingly, a longer time to death. In contrast, whereas wild-type PrV-infected pigs showed clinical signs and histological and histopathological findings typical of PrV infection, no signs of disease were observed after infection with PrV-gD− Pass. Moreover, in these animals, virus-infected cells were not detectable by immunohistochemical staining of different organ samples and no virus could be isolated from nasal swabs. Mutations in glycoproteins B and H were found to correlate with, and probably contribute to, gD-independent infectivity. In conclusion, although PrV-gD− Pass is virulent in mice, it is apparently unable to infect the natural host, the pig. This altered host range in vivo correlates with a difference of receptor usage in vitro and demonstrates for the first time the importance of gD receptors in alphaherpesvirus infection of an animal host.

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