Application of gene probes as diagnostic tools for White Spot Baculovirus (WSBV) of penaeid shrimp

Abstract

Since 1997, s lm~lar baculo\~iruses, w h ~ c h cause hlgh mortaht~es In p e n a e ~ d shrlmp, have been reported from Chlna, Japan, Korea, Thailand and T d ~ w a n All these baculov~rus-caused d~seases are characterlzed by the presence of w h ~ t e spots in the cutlcle To lsolate the agent of the dlsease referred to as Whlte Spot Syndrome (WSS) and W h ~ t c Spot Baculovlrus (WSBV], In t h ~ s paper, Penaeus van name^ and P styl~rostns were expcr~rnentally inoculated with homogenates ot infected Penaeus monodon from Thalland In t~ansmlsslon clectron nllcroscopy (TEM) the enveloped WSB\ v ~ ~ ~ o n s have a s u e of about 350 nm long and 130 nm wlde The nucleocapsids langc from 300 to 420 nm in length and 70 to 95 nm In diameter and show a supe~f~cla l ly segmented appearance Also present are unique paltlcles, w h ~ c h have not been observcd beforc, measuring 400 nm In length and 120 nm in w ~ d t h These particles are l a g e r than most of the usudl nucleocdpsids and have a cross-hatched superflclal appearance After nuc l e~c d c ~ d extraction, EcoRI-d~gested fragments of the WSBV genome were cloned Four of these fragments we're characterlzed and used as non-rad~oactive piobes labeled with DIG-11-dUTP Eiv In s ~ t u hybr ld~zdt~on, the probes hybrld~zed w ~ t h material located In nuclei of all LVSBV-~nfected tlssucs Previously reported talget tlssues, such as connective tlssue, epl the l~al tlssue and also hemocytes clearly showed p o s ~ t ~ v e h y b r ~ d ~ z a t ~ o n w ~ t h the plobes In add~ t ion , some llght ~ n f e c t ~ o n was revealed In the muscle and nervous tlssue K E Y WORDS Non-occluded b a c u l o v ~ ~ u s W h ~ t e Spot Syndrome Penaeid shrimp Gene probes In S I ~ L I hybr~dizatlon