RESUMO
OBJECTIVE: To study the effect of alpha-terthienyl (alpha-T) on protein, esterase and lipid peroxidation of Aedes albopictus larvae. METHODS: Sensitive and resistant strains of Aedes albopictus stage IV larvae were used. Bradford method was used to detect protein content. The breeding fluid of experiment group contained alpha-T (5.34 microg/L), and control group contained only acetone (3.95 microg/L). Histochemistry method was used to detect esterase activity. Larvae in the experiment group were cultured in fluid containing alpha-T (6.24 microg/L) but no alpha-T in the control group. TBA method was used to detect malondialdehyde (MDA). Larvae of the sensitive strain were divided into 5 sub-groups: A - acetone control (containing acetone 3.95 microg/L), B - ultra-violet irradiation (UV) control (same with A but treated by UV), C, D, E - experiment groups with alpha-T (4.58, 5.34 and 6.24 microg/L respectively). All groups were kept in dark condition for 1 hour, followed by UV for 1 hour (except group A), then fed under normal condition. RESULTS: With UV and alpha-T, the protein content of experiment group (1.225 mg/ml) was higher than that of control (1.120 mg/ml) (P<0.05) in sensitive strain; that of experiment group (1.199 mg/ml) was higher than that of control (1.114 mg/ml) (P<0.05) in the resistant strain. After 2, 4, 6, and 8 hour treated by both alpha-T and UV, the esterase activity all decreased in experiment group, and reached to the lowest 8 hours later (P<0.05). MDA contents was 2.286 nmol/mg protein in acetone control group and 2.322 nmol/mg protein in UV control, but 3.156, 4.188 and 4.684 nmol/mg protein respectively in the 3 experiment groups after treated by alpha-T and UV. The higher dose of alpha-T, the higher content of MDA (P<0.05). CONCLUSION: Under UV, alpha-T can increase the protein and MDA content of the larvae of Ae. albopictus but decrease the esterase activity.
