PROPERTIES OF DIGESTIVE CARBOHYDRASE ACTIVITIES SECRETED BY 2 COCKROACHES, PANESTHIA-CRIBRATA AND PERIPLANETA-AMERICANA

Carbohydrase activities in the xylophagous Panesthia cribrata and the omnivorous Periplaneta americana were localised in the foregut and mid gut and are endogenous. Levels of activities involved in the hydrolysi s of cellulose and hemicellulose were higher in P. cribrata, while tho se directed against starch and sucrose, by comparison, were elevated i n P. americana. Two endo-beta-1,4-glucanase (EC 3.2.1.4) and two endo- beta-1,4-xylanase (EC 3.2.1.8) components and additional components a ctive against laminarin or lichenin, were secreted in the gut of P. cr ibrata. Two major beta-glycosidase components, beta-GD1 and beta-GD2, were also secreted. beta-GD1 was a beta-fucosidase (EC 3.2.1.38), a be ta-mannosidase (EC 3.2.1.25) and a beta-glucosidase (EC 3.2.1.21), whi ch rapidly hydrolysed cellobiose, laminaribiose, and lactose. beta-Gal actosidase (EC 3.2.1.23) activity may also be partially associated wit h beta-GD1. beta-GD2 was a beta-xylosidase (EC 3.2.1.37), an alpha-L-a rabinosidase (EC 3.2.1.55) and a beta-glucosidase, but was less active against beta-linked disaccharides than was beta-GD1. One beta-N-acety lhexosaminidase (EC 3.2.1.52) and three alpha-galactosidase (EC 3.2.1. 22) components were also secreted by P. cribrata. Two of the alpha-gal actosidases may be associated with trehalase (EC 3.2.1.28) activity. A single sucrose alpha-glucosidase (EC 3.2.1.48) component hydrolysed s ucrose, maltose and other alpha-linked disaccharides. beta-fructofuran osidase (EC 3.2.1.26) activity is not secreted by P. cribrata. (C) 199 8 Elsevier Science Inc.