Aquatic Microbiology Lab, Department of Animal Health and Management, Alagappa University, Karaikudi, 630003, Tamil Nadu, India.
Department of Fisheries Science, Alagappa University, Karaikudi, 630003, Tamil Nadu, India.
Appl Biochem Biotechnol. 2024 Jan;196(1):18-31. doi: 10.1007/s12010-023-04489-8. Epub 2023 Apr 25.
Blood sucking parasites not only cause economic loss but also transmit numerous diseases. Dermanyssus gallinae, an obligatory blood feeding ectoparasite causes huge production loss to the poultry industry. Mosquitoes act as vector for transmitting several viral and parasitic diseases in humans. Acaricide resistance limits the control of these parasites. The present study was aimed to control the parasites using chitinase that have selective degradation of chitin, an important component in exoskeleton development. Chitinase was induced in Streptomyces mutabilis IMA8 with chitin extracted from Charybdis smithii. The enzyme showed more than 50% activity at 30-50 °C and the optimum activity at 45 °C. The enzyme activity of chitinase was highest at pH 7.0. The kinetic parameters K and V values of chitinase were determined by non-linear regression using Michaelis-Menten equation and its derivative Hanes-Wolf plot. The larvicidal effect of different concentrations of chitinase was evaluated against all instar larvae (I-IV) and pupae of An. stephensi and Ae. aegypti after 24 h of exposure. The percentage of mortality was directly proportional to the chitinase concentration. Bioassay for miticidal activity showed that chitinase had excellent miticidal activity (LC = 24.2 ppm) against D. gallinae. The present study suggested the usage of Streptomyces mutabilis for preparation of chitinase in mosquito and mite control.
吸血寄生虫不仅会造成经济损失，还会传播多种疾病。鸡皮刺螨是一种专性吸血的外寄生虫，会给家禽业造成巨大的生产损失。蚊子是传播人类多种病毒和寄生虫病的媒介。杀螨剂的抗性限制了这些寄生虫的控制。本研究旨在利用几丁质酶来控制寄生虫，几丁质酶对几丁质具有选择性降解作用，几丁质是外骨骼发育的重要组成部分。几丁质酶是在链霉菌 IMA8 中用从三疣梭子蟹中提取的几丁质诱导产生的。该酶在 30-50°C 时表现出超过 50%的活性，在 45°C 时活性最高。几丁质酶的酶活性在 pH7.0 时最高。用米氏方程及其导数 Hanes-Wolf 作图通过非线性回归确定了几丁质酶的动力学参数 K 和 V 值。用不同浓度的几丁质酶处理埃及伊蚊和致倦库蚊的所有龄期幼虫（I-IV）和蛹 24 小时后，评估其对幼虫的杀幼虫效果。死亡率与几丁质酶浓度成正比。杀螨活性测定表明，几丁质酶对鸡皮刺螨具有极好的杀螨活性（LC=24.2ppm）。本研究表明，可以利用变栖链霉菌来制备几丁质酶，用于控制蚊子和螨虫。
