B型烟粉虱与温室白粉虱不同虫态的碱性磷酸酶性质比较

为了探明B型烟粉虱Bemisia tabaci B-biotype 和温室白粉虱Trialeurodes vaporariorum体内的碱性磷酸酶(alkaline phosphatase，ALP)在两者竞争替代中所起的作用，以对硝基苯磷酸二钠 (pNPP)为底物，采用个体测定和群体测定的方法，研究比较了2种粉虱不同虫态中该酶的性质。结果表明：2种粉虱的碱性磷酸酶比活力在整个发育历期均逐渐增加，成虫期达到最大。温室白粉虱2至4龄若虫（伪蛹）期的碱性磷酸酶比活力分别是B型烟粉虱对应龄期酶比活力的2.58、2.68和3.14倍； B型烟粉虱雌雄成虫的碱性磷酸酶比活力分别是温室白粉虱雌雄成虫酶比活力的1.24和1.26倍，且2种粉虱雌虫的酶比活力显著大于其雄虫。2种粉虱2龄若虫到成虫的碱性磷酸酶最适pH均为7.8，最适温度均为47℃；在1龄若虫中均未能检测到该酶活性。测定并比较2种粉虱不同虫态碱性磷酸酶动力学特征参数的结果显示，温室白粉虱碱性磷酸酶在3、4龄若虫的亲和力以及在2, 3, 4龄若虫的酶蛋白浓度均显著大于B型烟粉虱的对应值，而在成虫期2种粉虱的亲和力、酶蛋白浓度无差异，B型烟粉虱的活化能显著小于温室白粉虱。据此推测，B型烟粉虱利用碱性磷酸酶在若虫期进行组织骨化和生长发育不如温室白粉虱，但羽化为成虫后利用其进行解毒代谢则可能强于温室白粉虱。

Comparison of alkaline phosphatase in Bemisia tabaci B-biotype(Homoptera: Aleyrodidae) and Trialeurodes vaporariorum (Homoptera:Aleyrodidae) at different developmental stages

For understanding the role of alkaline phosphatase (ALP) from Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) in their competition and substitute, the kinetic properties of the enzyme from the two whiteflies in different developmental stages were studied and compared by the individual assay and mass assay using pNPP as the substrate. The results showed that the alkaline phosphatase activity was increasing in both whiteflies during the whole growth period and reached the highest level at the adult stage. Comparatively, the alkaline phosphatase activity in the 2nd, 3rd and 4th (pseudopupa) instar of T. vaporariorum were 2.58, 2.68 and 3.14 times that in the corresponding instar of B. tabaci B-biotype, respectively. However, at the adult stage, the enzyme activities in female and male of B. tabaci B-biotype were 1.24 and 1.26 times that in T. vaporariorum, respectively. Moreover, the enzyme activities in females of both whiteflies were significantly higher than those in males. However, the enzyme activity of the alkaline phosphatase in the 1st instar of both whiteflies was not detected. The optimum pH and temperature for the enzyme activity in both whiteflies were 7.8 and 47℃, respectively. By testing the kinetic parameters of alkaline phosphatase from both whiteflies, we found that the affinity of the enzyme from the 3rd and 4th instar of T. vaporariorum was significantly higher than that from B. tabaci B-biotype of the corresponding instar, and also the protein concentrations of the enzyme from 2nd, 3rd and 4th instar of T. vaporariorum were significantly higher than those from B. tabaci B-biotype of the corresponding instars. But at the adult stage there was no significant difference between the two whiteflies in both the affinity of the enzyme and the protein concentration of the enzyme. Besides, the energy of activation (Ea) of the enzyme from T. vaporariorum adult was significantly higher than that from B. tabaci B-biotype adult. The results suggest that although the ability of B. tabaci B-biotype to utilize the alkaline phosphatase to promote the sclerotization and development during the larval stages may not as high as that of T. vaporariorum, its ability to utilize the enzyme to metabolize and detoxify the secondary (plant) substances and insecticides in the adult stage, however, is significantly higher than that of T. vaporariorum adult.