Some characteristics of digestive α-glycosidases from adults of Bruchus affinis Frölich, in relation with intestinal pH

Lagadic, Laurent

doi:10.1016/0300-9629(94)90092-2

Cited by 6 publications

(4 citation statements)

References 19 publications

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“…To be able to predict whether a particular inhibitor will be effective it would be useful to know the pH of the larval gut and to assay the effect of the inhibitor at that pH. A survey of the literature did not reveal any data on the pH of B. pisorum gut contents, but recent work (29) shows that the pH of the midgut of the related weevil, B. affinis, is in the pH range of 5.5 to 6.5 and that the amylase of this species has a pH optimum of 5.5.…”

Section: Relationship Between Inhibitor Effectiveness In the Field Trmentioning

confidence: 99%

Bean α-amylase inhibitor 1 in transgenic peas ( Pisum sativum ) provides complete protection from pea weevil ( Bruchus pisorum ) under field conditions

Morton

Schroeder

Bateman

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

237

125

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Two ␣-amylase inhibitors, called ␣AI-1 and ␣AI-2, that share 78% amino acid sequence identity and have a differential specificity toward mammalian and insect ␣-amylases are present in different accessions of the common bean (Phaseolus vulgaris). Using greenhouse-grown transgenic peas (Pisum sativum), we have shown previously that expression of ␣AI-1 in pea seeds can provide complete protection against the pea weevil (Bruchus pisorum). Here, we report that ␣AI-1 also protects peas from the weevil under field conditions. The high degree of protection is explained by our finding that ␣AI-1 inhibits pea bruchid ␣-amylase by 80% over a broad pH range (pH 4.5-6.5). ␣AI-2, on the other hand, is a much less effective inhibitor of pea bruchid ␣-amylase, inhibiting the enzyme by only 40%, and only in the pH 4.0 -4.5 range. Nevertheless, this inhibitor was still partially effective in protecting field-grown transgenic peas against pea weevils. The primary effect of ␣AI-2 appeared to be a delay in the maturation of the larvae. This contrasts with the effect of ␣AI-1, which results in larval mortality at the first or second instar. These results are discussed in relationship to the use of amylase inhibitors with different specificities to bring about protection of crops from their insect pests or to decrease insect pest populations below the economic injury level.

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Section: Relationship Between Inhibitor Effectiveness In the Field Trmentioning

confidence: 99%

Bean α-amylase inhibitor 1 in transgenic peas ( Pisum sativum ) provides complete protection from pea weevil ( Bruchus pisorum ) under field conditions

Morton

Schroeder

Bateman

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

237

125

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“…Both glycogen level and glycogenolysis enzymes can therefore be used as biomarkers of environmental stress. Similarly, the enzymes involved in carbohydrate metabolism are potent biomarkers of pollution in invertebrates (Lagadic andChararas 1988, Lagadic 1994, W. Baturo, L. Lagadic andTh. Caquet submitted).…”

Section: Energy-yielding Substrates: Glycogen and Glucosementioning

confidence: 99%

The role of biomarkers in environmental assessment (5). Invertebrate populations and communities

1994

Self Cite

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Although a number of biomarkers of pollutant exposure have been identified in invertebrate species, direct linkage with changes at population and/or community levels are poorly documented and, despite the ecological importance of invertebrates, there is no conclusive evidence that individual measurements of biochemical parameters may allow the effects of pollutants on populations and communities to be predicted. Among the various biochemical parameters used as biomarkers in invertebrates exposed to pollutants in the field, only those for which changes at population or community level can be suggested are discussed in the present review. At population and community levels, the development of resistance to pesticides and changes in behaviour, reproduction and development are analysed as putative consequences of biochemical and physiological alterations. Limits to the use of biochemical parameters as biomarkers of invertebrate exposure to pollutants are discussed. Future research trends and experimental approaches to the validation of invertebrate biomarkers in environmental pollution assessment are suggested.

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“…1, 2, and 3), which corresponds to the pHs found in the midguts of the following bruchids C. maculatus (Kitch and Murdock, 1986;Silva et al, 1999), Acanthoscelides obtectus (Osuala et al, 1994), and Bruchus pisorum (Lagadic, 1994). The use of in gel assays to determine pH optima showed that Z. subfasciatus possessed at least one proteinase that is stable during the mildly-denaturing electrophoresis and has a pH optimum lower than the pH found in the luminal contents.…”

Section: Discussionmentioning

confidence: 96%

Differences in midgut serine proteinases from larvae of the bruchid beetles Callosobruchus maculatus and Zabrotes subfasciatus

Silva

Terra

Lima

2001

Arch Insect Biochem Physiol

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Proteinase activities in the larval midguts of the bruchids Callosobruchus maculatus and Zabrotes subfasciatus were investigated. Both midgut homogenates showed a slightly acidic to neutral pH optima for the hydrolysis of fluorogenic substrates. Proteolysis of epsilon-aminocaproil-Leu-Cys(SBzl)-MCA was totally inhibited by the cysteine proteinase inhibitors E-64 and leupeptin, and was activated by 1.5 mM DTT in both insects, while hydrolysis of the substrate Z-ArgArg-MCA was inhibited by aprotinin and E-64, which suggests that it is being hydrolysed by serine and cysteine proteinases. Gel assays showed that the proteolytic activity in larval midgut of C. maculatus was due to five major cysteine proteinases. However, based on the pattern of E-64 and aprotinin inhibition, proteolytic activity in larval midgut of Z. subfasciatus was not due only to cysteine proteinases. Fractionation of the larval midgut homogenates of both bruchids through ion-exchange chromatography (DEAE-Sepharose) revealed two peaks of activity against Z-ArgArg-MCA for both bruchid species. The fractions from C. maculatus have characteristics of cysteine proteinases, while Z. subfasciatus has one non-retained peak of activity containing cysteine proteinases and another eluted in a gradient of 250-350 mM NaCl. The proteolytic activity of the retained peak is higher at pH 8.8 than at pH 6.0 and corresponds with a single peak that is active against N-p-tosyl-GlyGlyArg-MCA, and sensitive to 250 microM aprotinin (90% inhibition). The peak contains a serine proteinase which hydrolyzes alpha-amylase inhibitor 1 from the common bean (Phaseolus vulgaris). Arch.

show abstract

Some characteristics of digestive α-glycosidases from adults of Bruchus affinis Frölich, in relation with intestinal pH

Cited by 6 publications

References 19 publications

Bean α-amylase inhibitor 1 in transgenic peas ( Pisum sativum ) provides complete protection from pea weevil ( Bruchus pisorum ) under field conditions

Bean α-amylase inhibitor 1 in transgenic peas ( Pisum sativum ) provides complete protection from pea weevil ( Bruchus pisorum ) under field conditions

The role of biomarkers in environmental assessment (5). Invertebrate populations and communities

Differences in midgut serine proteinases from larvae of the bruchid beetles Callosobruchus maculatus and Zabrotes subfasciatus

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