Role of 3,4-dihydroxyphenyl alanine in the nodulation response of silkworm Bombyx mori L. to bacterial infection

摘要

The relationship between nodulation response to bacterial infection and exogenous application of 3,4-DL-dihydroxyphenyl alanine has been examined in the silkworm Bombyx mori. Intrahaemocoelic injections of the bacteria Bacillus thuringiensis var. sotto, to fifth instar larvae, followed immediately by injections of 3,4-dopa resulted in significant (P < 0.01) depletion of haemocytes from general circulation in comparison to infected vehicle-treated controls. The nodulation response of the insect was also enhanced. Treatment with haloperidol, a dopamine receptor inhibitor, impaired the nodulation response as well as deployment of haemocytes in the defensive process. The inhibitory effects on nodulation were seen Ih after infection, which was evidenced by lesser cellular aggregates and nodules. On the other hand, treatment with dopa + haloperidol following infection neutralized the effect of dopa (or dopamine). These findings are indicative of a specific role for dopa in the discrete cellular events leading to nodulation. [References: 33]