Structural features of the salivary gland hypertrophy virus of the tsetse fly revealed by cryo-electron microscopy and tomography

Abstract BackgroundTherefore, tsetse control is considered an effective and sustainable tactic for the control of cyclically transmitted trypanosomosis in the absence of effective vaccines and inexpensive, effective drugs. The sterile insect technique (SIT) is currently used to eliminate tsetse fly populations in an area-wide integrated pest management (AW-IPM) context in Senegal. For SIT, tsetse mass-rearing is a major milestone that associated microbes can influence. Tsetse flies can be infected with micro-organisms, including the primary and obligate Wigglesworthia glossinidia, the commensal Sodalis glossinidius, and Wolbachia pipientis. In addition, tsetse populations often carry a pathogenic DNA virus, the Glossina pallidipes Salivary Gland Hypertrophy Virus (GpSGHV) that hinders tsetse fertility and fecundity. Interactions between symbionts and pathogens might affect the performance of the insect host. MethodsIn the present study, we assessed the possible interaction of GpSGHV and tsetse endosymbionts under field conditions to decipher the bidirectional interactions in different Glossina species. We determined the co-infection pattern of GpSGHV and Wolbachia in natural tsetse populations. We further analyzed the interaction of both Wolbachia and GpSGHV infection with Sodalis and Wigglesworthia density using qPCR. ResultsThe results indicated that the co-infection of GpSGHV and Wolbachia was most prevalent in Glossina austeni and Glossina morsitans morsitans, with an explicit significant negative correlation between GpSGHV and Wigglesworthia infection. GpSGHV infection levels of more than 104 were not observed when Wolbachia infection was present at high density (>108.5), suggesting a potential protective role of Wolbachia against GpSGHV. ConclusionThe result indicates that Wolbachia infection might protect tsetse fly against GpSGHV and the interactions between the tsetse host and its associated microbes are dynamic, likely species-specific and significant differences may exist between laboratory and field conditions.

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Tsetse Salivary Gland Hypertrophy Virus: Hope or Hindrance for Tsetse Control?

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0001220 ◽

2011 ◽

Vol 5 (8) ◽

pp. e1220 ◽

Cited By ~ 32

Author(s):

Adly M. M. Abd-Alla ◽

Andrew G. Parker ◽

Marc J. B. Vreysen ◽

Max Bergoin

Keyword(s):

Salivary Gland ◽

Tsetse Control ◽

Salivary Gland Hypertrophy ◽

Salivary Gland Hypertrophy Virus

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Prevalence of trypanosomes, salivary gland hypertrophy virus and Wolbachia in wild populations of tsetse flies from West Africa

BMC Microbiology ◽

10.1186/s12866-018-1287-4 ◽

2018 ◽

Vol 18 (S1) ◽

Cited By ~ 4

Author(s):

Gisele M. S. Ouedraogo ◽

Güler Demirbas-Uzel ◽

Jean-Baptiste Rayaisse ◽

Geoffrey Gimonneau ◽

Astan C. Traore ◽

...

Keyword(s):

Salivary Gland ◽

West Africa ◽

Tsetse Flies ◽

Wild Populations ◽

Salivary Gland Hypertrophy ◽

Salivary Gland Hypertrophy Virus

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Cryo-electron Microscopy Structures of Novel Viruses from Mud Crab Scylla paramamosain with Multiple Infections

Journal of Virology ◽

10.1128/jvi.02255-18 ◽

2019 ◽

Vol 93 (7) ◽

Cited By ~ 3

Author(s):

Yuanzhu Gao ◽

Shanshan Liu ◽

Jiamiao Huang ◽

Qianqian Wang ◽

Kunpeng Li ◽

...

Keyword(s):

Electron Microscopy ◽

3D Structure ◽

Structural Features ◽

Economic Losses ◽

Scylla Paramamosain ◽

Multiple Infections ◽

Mud Crab ◽

Cryo Electron Microscopy ◽

Novel Virus ◽

Icosahedral Capsid

ABSTRACT Viruses associated with sleeping disease (SD) in crabs cause great economic losses to aquaculture, and no effective measures are available for their prevention. In this study, to help develop novel antiviral strategies, single-particle cryo-electron microscopy was applied to investigate viruses associated with SD. The results not only revealed the structure of mud crab dicistrovirus (MCDV) but also identified a novel mud crab tombus-like virus (MCTV) not previously detected using molecular biology methods. The structure of MCDV at a 3.5-Å resolution reveals three major capsid proteins (VP1 to VP3) organized into a pseudo-T=3 icosahedral capsid, and affirms the existence of VP4. Unusually, MCDV VP3 contains a long C-terminal region and forms a novel protrusion that has not been observed in other dicistrovirus. Our results also reveal that MCDV can release its genome via conformation changes of the protrusions when viral mixtures are heated. The structure of MCTV at a 3.3-Å resolution reveals a T= 3 icosahedral capsid with common features of both tombusviruses and nodaviruses. Furthermore, MCTV has a novel hydrophobic tunnel beneath the 5-fold vertex and 30 dimeric protrusions composed of the P-domains of the capsid protein at the 2-fold axes that are exposed on the virion surface. The structural features of MCTV are consistent with a novel type of virus. IMPORTANCE Pathogen identification is vital for unknown infectious outbreaks, especially for dual or multiple infections. Sleeping disease (SD) in crabs causes great economic losses to aquaculture worldwide. Here we report the discovery and identification of a novel virus in mud crabs with multiple infections that was not previously detected by molecular, immune, or traditional electron microscopy (EM) methods. High-resolution structures of pathogenic viruses are essential for a molecular understanding and developing new disease prevention methods. The three-dimensional (3D) structure of the mud crab tombus-like virus (MCTV) and mud crab dicistrovirus (MCDV) determined in this study could assist the development of antiviral inhibitors. The identification of a novel virus in multiple infections previously missed using other methods demonstrates the usefulness of this strategy for investigating multiple infectious outbreaks, even in humans and other animals.

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