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

Abstract

Since 1997, slm~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 ~s e a s e s 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~clally 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 n u c 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 hybrld~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, eplthel~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 a d d ~t i o n , some llght ~n f e c t ~o n was revealed In the muscle and nervous tlssue