Serotonin (5-HT) plays a vital role in many physiological processes in insects, regulating physiological activities such as growth and movement through multiple 5-HT receptors (5-HTRs), which were potential targets for some new insecticides. However, the specific function of individual 5-HTRs in Ae. aegypti is still unclear. In this study, we investigated the function of the 5-HT7A receptor during Ae. aegypti development. 5-HTR7A transcripts were detected at all stages of development by real-time PCR. The results indicated that the gene expression was highest in the limbs (p < 0.01). We also generated 5-HTR7A mutant mosquitoes using CRISPR-mediated gene editing. The mutants had an abnormal phenotype at the larval stage, including an aberrant head-to-chest ratio and decreased motor activity. The mutant pupae developed abnormally, and most died (56.67%) (p < 0.0001). Using external stimuli to larvae and pupae with abnormal phenotypes, we found the mutant G1 and G2 generations responded to external stimuli in a longer time than the wild-type (WT) mosquitoes, and most of the mutants were 2 to 3 s slower than the WTs to respond to external stimuli (p < 0.01). Due to higher mortality, mutant larvae and pupae had fewer numbers than the WTs. The egg hatching rate of mutant G1 and G2 generations was lower than that of the WTs (p < 0.01). The expression level of 5-HTR7A in the mutants decreased by about 65% compared with the control group using real-time PCR (p < 0.05). In all, the 5-HT7A receptor plays an important role in the metamorphosis, development and motor function of Aedes aegypti.
A dye recycled photosensitization system composed of Eosin Ethyl Ester Iodonium Salt (EOEtIPh2) and basic H-donor has been designed. As a result of studies in the mechanism of electron transfer reaction of xanthene iodonium salt, it is proposed that the dye-recycled process consists of three-step reactions during the photosensitization: The oxidative fading product (I) of due is formed through electron transfer under irradiation; In the presence of H-donor, product (I) changes into acidic leuco dye product (II); Product (II) undergoes deprotonization under action of base to regenerate initial dye. The roles of light, H-donor and base are three major factors in the process of dye regeneration. The results obtained show that their efficiency of sensitization is 4 times higher than that of single system EOErIPh2, and the photopolymerization rate is also significantly promoted due to multiplication of radicals formed in the dye recycled photosensitization process.
The photochemical properties of a series of xanthene dye bis(diphenyliodonium) salts (XT(JPh2)2) were compared. The results of fluorescence quenching demonstrate that the electron transfer of XT(Iph2)2 is mainly from ion pair and the quenching rate constants approach 1011-12M-1s-1 that is well above the rate limit controlled by diffusion. Effects of halogen substituents in the ortho positions adjacent to phenoxyl group in xanthene moiety directly affect their photoreactivities and dark storage stabilities. XT(Iph2)2 salts were applicable for vinyl monomers and the efficiency of polymerization depends on the rate of photogeneration of active radicals. Effects of solvent polarity and concentration of XT(Iph2)2 were also investigated.
Mono- and di- iodonium salts of eosin dye, EoEt( Ph2 I) and Eo( Ph2 I)2, as a novel sensitization system for visible photopolymerization were synthesized and studied in comparison with the corresponding bimocular systems (EoNa2/Ph2 ICl). The photochemical activity of unimolecular system is much higher than that of bimolecular system. Photobleaching rate obtained decreases in the order Eo(Ph2 I)2> EoNa2/2 (Ph2 ICl)> EoEtNa/2 (Ph2 ICl). The same results for radical polymerization were also obtained. The kinetic results of polymerization with Eo(Ph2 I)2 as initiator show that the polymerization rate is directly proportional to the concentration of MMA and Eo (Ph2 I)2 with exponent of 1.0 and 0.46 respectively. The overall activation energy of polymerization was measured to be 7.0 (kcal.mol-1). The photopolymerization rate is affected significantly by solvent polarity as a results of variance in absorption spectrum. Multiacrylate photocrosslinking rates obtained in the dry film indicate that the disalt Eo(Ph2 I)2 is more efficient than mono salt EoEt(Ph2 I) and essentially, no reaction occures in the case of bimolecular system (EoNa2/Ph2 ICl)
nor in air. Comparing the THITA/TMPTA andTHITA/PETA mixtures, the parameters of photopolymerization and hardness of photocured samples show asmall difference and only change slightly with varying molar ratios of mixture. In the presence of inorganicfiller, the hardness of photocuring resins is almost the same as that for commercial products.
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