Author
|
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/30/2007 Publication Date: 9/1/2007 Citation: Valles, S.M. 2007. Ethanol Preservation of fire ants allows retrospective screening for Solenopsis Invicta Virus-1. Florida Entomologist. 90(3):577-578. Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 300 million acres. It causes significant economic losses (approximately $5 million) in livestock and agricultural production and poses a threat to human health. The recently discovered fire ant virus, SINV-1, offers promise as a microbial agent of control or gene delivery system for the fire ant. Some studies would benefit by being able to retrospectively examine alcohol-archived fire ants for the presence of SINV-1. A USDA-ARS scientist at the Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) has determined that storage of fire ant workers in 95% ethanol provides sufficient protection for SINV-1 nucleic acids for subsequent molecular analysis. This information should aid future epidemiologic and phylogenetic studies on alcohol-preserved specimens of fire ants. Technical Abstract: Solenopsis invicta virus-1 (SINV-1) is a positive-strand RNA virus assigned to the Dicistroviridae that appears to infect ants only in the Solenopsis genus. Because the virus was only recently discovered and it is the only currently known virus to infect S. invicta, basic knowledge about its biology is lacking. Epidemiologic and phylogenetic studies would certainly benefit if the virus could be examined in archived samples. To address this question, we archived SINV-1-positive S. invicta worker ants in 95% ethanol and tested the ants for the presence of SINV-1 on an irregular basis over a 2-year period. In addition, we examined 2-propanol- and ethanol-archived S. invicta samples from 1999 and 2001, respectively, for the presence of SINV-1. At every time point over the course of the 2 year study, SINV-1 was detected by RT-PCR. Only 3 preparations, 119, 147, and 723 days in ethanol, failed to produce an amplicon. SINV-1 RNA in those samples was most likely degraded to a point that precluded cDNA synthesis and subsequent amplification, or the ants sampled at that time were not infected with SINV-1; the frequency of the infection in the colony of ants chosen for the study was never determined. The ability to examine ant samples retrospectively provides a unique opportunity that could facilitate epidemiologic and phylogenetic studies. |
