About this Agricultural and Biological Sciences article

α-galactosidase activity in ingested seeds and in the midgut of Dysdercus peruvianus (Hemiptera: Pyrrhocoridae) by Carlos P. Silva; Walter R. Terra is a Agricultural and Biological Sciences article available to read on EtoBox.

The midgut of Dysdercus peruvianus is divided into three main sections (V 1 -V 3 ) and is linked through V 4 to the hindgut. The distribution of α-galactosidase activity in the different gut segments of D. peruvianus females was studied. αgalactosidase hydrolyzes the trisaccharide raffinose, the major carbohydrate of cotton seeds, on which the insects live. In D. peruvianus midgut, α-galactosidase activity is mainly found in soluble fractions of V 1 contents. However, a comparison between specific activities using different α-galactosidase substrates in cotton seed extracts, V 1 tissue homogenate, and midgut contents suggested that the contribution of the enzymes from seeds may be very significant. Gel filtration on Sephacryl S-200 of samples from seed extracts, V 1 tissue, and V 1 contents revealed that in all samples raffinose hydrolysis is accomplished by αgalactosidases with similar M r (30,000 ± 3,000) and does not involve the activity of a β-fructosidase. Thermal inactivation studies of extracts from the three sources suggested that there was only one molecular form of the insect αgalactosidase and that the activity found in V 1 contents includes enzymes derived from the seed

Author

Carlos P. Silva; Walter R. Terra

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Inc.; Wiley (ISSN 0739-4462)

Published

1997

Language

EN

Field

Agricultural and Biological Sciences (Life Sciences)