PROCESS FOR PREPARING THE VIRUS OF ACUTE PARALYSIS OF BEES

摘要

Viruses causing acute paralysis in bees are obtd. as follows: 80 virus-infected bees'-heads are powdered and treated as quickly as possible in the cold with 20 vols. of TFS soln. at pH7 and contg. 40000 1U-s/ml penicillin G, 200 1U-s/ml di:hydro-strepto-mycin and 100 1U-s/ml stamycin. The prepn. is then frozen three times at -20 deg.C temp. having been at, or reaching, room temp. prior to freezing. The prepn. is treated ultrasonically at 150-250 KHz for 10 mins. and treated with 2 vols. of 0.5% trypsin soln. at 37 deg.C for 15 mins. followed by centrifuging for 10 mins. at 3000 rpm. 5-9 days old embryos contg. hens eggs are inoculated with the aq. virus supernatant. The inoculated eggs are incubated for four days at 35 deg.C. Dead embryos are collected together with those showing lesions after 48-96 hrs.. These represent a viral mass which either may be used in fresh state or having been lyophilised in medium of lactose.