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Title: ALKALINE PROTEINASE (SERINE PROTEINASE) ARE NOT PRESENT IN SILVERLEAF OR SWEETPOTATO WHITEFLIES

Author
item COHEN, ALLEN
item BRUMMETT, DONALD

Submitted to: Sweetpotato Whitefly Progress Review Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: We tested both silverleaf and sweetpotato whiteflies for proteinase activity and found none. Using 3-5 g of fresh whitefly adults in the case of B. argentifolii and 0.5 mg of B. tabaci, we made extracts that we concentrated and tested against casein gel, azocasein and azoalbumin at pH 7.4 and 25 deg C. All tests with Bemisia were negative, while for positive standards, we used an extract equivalent to 0.1 Lygus hesperus salivary gland, and we obtained clear-cut proteinase activity from all three methods with the Lygus extract. We further tested the whitefly and Lygus extracts using benzoylarginine-p-nitroanilide (BAPNA) as a substrate for trypsin-like activity. We had strong positive readings from the Lygus extracts and no positives from the whiteflies. We doubled the incubation time on the casein agar plates to increase the sensitivity, and we incubated at 37 deg C to further enhance possible reaction, and again we had negative results with the whitefly extracts and we had very strong positive results with the Lygus extracts. These results led us to the conclusion that neither B. argentifolii nor B. tabaci has a semine (alkaline) proteinase.