Control of the release of digestive enzymes in the cricket Gryllus bimaculatus and the fall armyworm, Spodoptera frugiperda
type: CreativeWork
description: This thesis investigates control of the release of digestive enzymes in the cricket Gryllus bimaculatus and the fall armyworm, Spodoptera frugiperda. 1. Control of enzyme release in the cricket G. bimaculatus. Using flat-sheet preparations of the caecum, digestive enzyme release was investigated. More trypsin, aminopeptidase and amylase are secreted in the caecum of fed crickets than in unfed crickets, but basal levels of certain enzymes are released continuously even in unfed animals. A variable ratio of nutrients in ingested food leads to a different ratio of digestive enzyme release, but a high nutrient component in the food does not necessarily induce a high digestive enzyme release for that component. Maltose and glucose elevate amylase release from the tissues into the incubation medium, but starch does not. Bovine serum albumin (BSA), peptone and a mixture of amino acids have almost no effect on the release of aminopeptidase, and only low concentrations of peptone increase trypsin release. In crickets, the continuous release of proteases is sufficient to meet the needs for growth, and only moderate stimulation of trypsin results from feeding. Carbohydrates are used for energy, and the release of amylase is adjusted to the amount of food ingested. The neuropeptide allatostatin Grybi-AS 5 elevates the release of amylase in fed females, but not of trypsin or aminopeptidase, however, both amylase and trypsin release are stimulated by AS 5 in unfed crickets. Fed crickets have sufficient trypsin to obtain needed amino acids, but unfed do not, therefore the AS stimulation of trypsin release in unfed crickets makes sense. 2. Control of enzyme release in the larvae of S. frugiperda. A flat-sheet preparation of the ventriculus was used to test the release of amylase, trypsin and aminopeptidase in response to specific nutrients in the food and to specific neuropeptides. The epithelial secretion rate of amylase and trypsin was about 20% of the amount of enzyme present in…
abstract: This thesis investigates control of the release of digestive enzymes in the cricket Gryllus bimaculatus and the fall armyworm, Spodoptera frugiperda. 1. Control of enzyme release in the cricket G. bimaculatus. Using flat-sheet preparations of the caecum, digestive enzyme release was investigated. More trypsin, aminopeptidase and amylase are secreted in the caecum of fed crickets than in unfed crickets, but basal levels of certain enzymes are released continuously even in unfed animals. A variable ratio of nutrients in ingested food leads to a different ratio of digestive enzyme release, but a high nutrient component in the food does not necessarily induce a high digestive enzyme release for that component. Maltose and glucose elevate amylase release from the tissues into the incubation medium, but starch does not. Bovine serum albumin (BSA), peptone and a mixture of amino acids have almost no effect on the release of aminopeptidase, and only low concentrations of peptone increase trypsin release. In crickets, the continuous release of proteases is sufficient to meet the needs for growth, and only moderate stimulation of trypsin results from feeding. Carbohydrates are used for energy, and the release of amylase is adjusted to the amount of food ingested. The neuropeptide allatostatin Grybi-AS 5 elevates the release of amylase in fed females, but not of trypsin or aminopeptidase, however, both amylase and trypsin release are stimulated by AS 5 in unfed crickets. Fed crickets have sufficient trypsin to obtain needed amino acids, but unfed do not, therefore the AS stimulation of trypsin release in unfed crickets makes sense. 2. Control of enzyme release in the larvae of S. frugiperda. A flat-sheet preparation of the ventriculus was used to test the release of amylase, trypsin and aminopeptidase in response to specific nutrients in the food and to specific neuropeptides. The epithelial secretion rate of amylase and trypsin was about 20% of the amount of enzyme present in…
author: Lwalaba, Digali
date published: 2010-06-02
date modified: 2026-07-27T18:49:12Z
provider: Universität Bayreuth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universität Bayreuth