Impaired Geotaxis as a Novel Phenotype of Nora Virus Infection of Drosophila melanogaster.

Abigail Rogers,Lesley Towery,Kimberly A Carlson,Amanda Mccown

doi:10.1155/2020/1804510

Abstract

Nora virus (NV) is a picorna-like virus that contains a positive-sense, single-stranded RNA genome. The virus infects Drosophila melanogaster with no known characterized phenotype. In this study, geotaxis assays and longevity analyses were used to determine if Nora virus infection affects D. melanogaster's locomotor ability. In addition, Drosophila C virus (DCV), a well-characterized D. melanogaster virus, was used as a positive control, as it has previously shown a locomotor defect in infected flies. Stocks infected with NV (NV+) and DCV (DCV+) and virus-free (NV-/DCV-) stocks were established. Over a 3-year period, approximately 2,500 virgin female flies were tested for geotaxis and longevity using Kaplan–Meier analyses, as well as the Cox Proportional Hazards regression for survivorship. There was a significant decrease in the geotaxis when the D. melanogaster flies were infected with Nora virus compared to uninfected controls, but no difference was found between DCV+ and NV+ trials. There were not significant differences in longevity between the three groups. This is the first time that a phenotype has been recorded in association with Nora virus infection. Overall, the data demonstrate that geotaxis dysfunction may be a phenotypic hallmark of Nora virus infection.

Highlights

Drosophila melanogaster is a model organism commonly used in biological studies to study virus effects because its DNA is similar enough to humans that they can be used as a model for human immunity and disease [1], as well as development and behavior
Geotaxis Analysis. e geotaxis analysis showed a significant difference in the locomotor function between Nora virus (NV)+ and uninfected flies (p < 0.0001). e uninfected group had a greater climbing ability than the NV+ (Figure 1)
When comparing NV+ to the Drosophila C virus (DCV)+, the data showed there was a significant difference in the climbing ability between the two groups (p < 0.0001) with the NV+ having greater locomotor function than the DCV+ (Figure 2)

Summary

Introduction

Drosophila melanogaster is a model organism commonly used in biological studies to study virus effects because its DNA is similar enough to humans that they can be used as a model for human immunity and disease [1], as well as development and behavior. Locomotor function is a basic measurement, it is vital for other important behaviors such as survival and reproduction [5] Another important characteristic to be studied in response to viral infection is longevity. One early study demonstrated that DCV infection caused a decrease in lifespan with 30–50% of the flies dying within a week [6]. While others, such as Rhabdovirus sigma, are not lethal and have no effect on lifespan [7]. Erefore, the importance of locomotor function and longevity in D. melanogaster makes these good metrics for characterizing a possible disease phenotype associated with a viral infection, especially one that has no known phenotype, such as Nora virus While others, such as Rhabdovirus sigma, are not lethal and have no effect on lifespan [7]. erefore, the importance of locomotor function and longevity in D. melanogaster makes these good metrics for characterizing a possible disease phenotype associated with a viral infection, especially one that has no known phenotype, such as Nora virus

Methods

Results

Conclusion