Reference Report for IND87001245
| Title: | Plant proteinase inhibitors: mechanism of action and effect on the growth and digestive physiology of larval Heliothis zea and Spodoptera exiqua. |
| Authors: | Broadway, R.M., Duffey, S.S. |
| Source: | J. Insect Physiol. 1986, 32(10):827-833 |
| Abstract: | We compared soybean trypsin inhibitor and potato proteinase inhibitor II in relation to their effects on the growth and digestive physiology of larval H. zea (Boddie) and S. exiqua (Hubner). When incorporated into an artificial diet, both proteinase inhibitors significantly reduced the growth and development of the larvae. However, when the artificial diet containing the proteinase inhibitor was supplemented with methionine, the reduction of growth did not occur. The proteinase inhibitors had no effect on the in vivo digestion of protein, indicating that they do not reduce the level of digested protein. However, when the larvae chronically ingest the proteinase inhibitors, there was significant elevation of the level of tryptic activity (the primary alimentary protease for both species of insect). Thus, we conclude that the mode of action of proteinase inhibitors is to cause the pernicious hyperproduction of trypsin. This, coupled with insufficient dietary availability of sulphur-containing amino acids (i.e. methionine) needed for enzyme synthesis, results in inhibition of growth. Thus, protein quantity-quality is very important in dictating the anti-nutritional effects of plant proteinase inhibitors on herbivorous insects. |
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