Fig 17 - uploaded by Fang Zhu
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Generalized Mechanism for sclerotization of insect cuticle. Adapted with permission from Sugumaran (231,232). Phenoloxidase generated quinones react with proteins and chitin forming adducts (called quinone tanning). Quinones also serve as substrates for quinone isomerase generating quinone methides that react with proteins and chitin (Quinone methide sclerotization). Quinone methides are converted by quinone methide isomerase to dehydro-N-acyldopamine, which is further oxidized by phenoloxidases producing quinone methide imine amide that will generate adducts and crosslinks (quinone methide sclerotization). The generalized mechanism is also applicable to N-β-alanyldopamine.
Source publication
Entomology now is a diversified science discipline, deviating considerably from the incorporated
principles of Molecular biology, Genetics and Biochemistry. It has provided necessary tools for
transferring and evaluating genetic characteristics not only for a host of insects, but also for related
host plants. The molecular approaches have enabled t...
Citations
Abstract The effects of heat shock on survival and reproduction of two whitefly species, Trialeurodes vaporariorum (Westwood) and Bemisia tabaci (Gennadius) biotype B (Homoptera: Aleyrodidae), were compared in the laboratory. Whitefly adults were exposed to 26 (control), 37, 39, 41, 43 and 45 degrees C for 1 hour, and were then maintained at 26 degrees C. Adult survival was significantly affected when they were exposed at 41 degrees C or higher for B. tabaci or 39 degrees C or higher for T. vaporariorum. All males of T. vaporariorum were killed at 45 degrees C. In both whitefly species, females were more tolerant to high temperatures at 39 degrees C or higher than males. Female fecundity was not significantly different when B. tabaci adults were heat-shocked at all temperatures. In contrast, the fecundity of T. vaporariorum females declined with the increase of temperature, and only a few eggs were oviposited at 43 degrees C. Survival or hatch rates of the F1 nymphs of both whitefly species declined as heat-shock temperature increased, and no T. vaporariorum nymphs were hatched at 43 degrees C. Similarly, percentages of F1 offspring developing to adults for both whitefly species also declined as the heat-shock temperature increased. Sex ratios of the F1 offspring were not significantly affected for T. vaporariorum but were slightly affected for B. tabaci at 43 and 45 degrees C. The significance of heat shock in relation to dispersal, distribution and population dynamics of the two whitefly species is discussed.
