Browsing by Author "Zhang, Donghui"

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    Adaptation and carry over effects of extreme sporadic heat stress in Culex mosquitoes
    (Elsevier, 2024-10-09) Padde, John Roberts; Zhou, Yinghui; Chen, Yunxuan; Zhu, Yuxiao; Yang, Yuxuan; Hou, Min; Chen, Lu; Xu, Zhipeng; Zhang, Donghui; Chen, Lin
    Mosquitoes, as temperature-sensitive ectothermic vectors, exhibit temperature-dependence. This study investigates Culex pipiens pallens (Cx. pallens) responses to abrupt temperature increases and their implications on mosquito physiology. First instar larvae (24hr post hatching) and newly enclosed adults (24hr post emergence) were separately exposed to heat shock regimes of 33 °C, 37 °C, and 42 °C for 3 days alongside a control temperature of 27 °C. Results showed that mortality was triggered at 42 °C within a day. Adult male mosquitoes were less tolerant to all temperatures than larvae and adult females (p < 0.05). Exposing larvae to constant temperatures for 3 days significantly decreased larvae's development time, growth rate and adult emergence (p < 0.05). Reproductive fitness was significantly reduced (p < 0.05) in males emerging from larvae exposed to 37 °C. Life table parameters showed significant increased mortality rate, kill power and decreased life expectancy at the embryonic stage (p < 0.05). Furthermore, heatwaves deactivated the Transient receptor protein ankyrin 1 at 37 °C (p < 0.05) in larvae but not adults. Calmodium, Heat shock protein 90, and small heat shock protein expression were significantly decreased in larvae at 37 °C (p < 0.05) as compared to larvae raised at 33 °C and 27 °C. In conclusion, we classified the heat waves into three categories: adaptable (33 °C), critical (37 °C), and fatal (42 °C). Prolonged exposure of Culex pallens larvae to extreme heat affects the male reproductive output. These findings may serve as an important reference for forecasting vector and pest dynamics and used to tailor mosquito prevention and control measures.
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    The impact of environmental and host factors on wolbachia density and efficacy as a biological tool
    (Decoding Infection and Transmission, 2023-11-15) Padde, John Roberts; Lu, Qingyu; Long, Yuang; Zhang, Donghui; Hou, Min; Chen, Lu; Xu, Zhipeng; Chen, Lin; Ji, Minjun
    Wolbachia, a bacterium found naturally in some species of Aedes and Culex mosquitoes, has gained significant attention for it's potential in controlling mosquito-borne diseases and suppressing mosquito populations. However, Wolbachia-mediated pathogen blockage, Wolbachia dynamics in field populations and vertical transmission have been reported to be density-dependent. Several factors, including host genetics, diet, temperature, and co-infections can influence Wolbachia titers within its host. The interplay between these factors can have significant influence on the effectiveness of Wolbachia-mediated pathogen blockage and cytoplasmic incompatibility. However, there is a knowledge gap regarding the regulation of Wolbachia density within its host, which could affect its effectiveness as a biocontrol tool. Therefore, this review aims to understand the complex tripartite association between the environment, host, and endosymbiont, and how these relationships are crucial in harnessing the full potential of Wolbachia as a biological tool. Further, we highlight how host, pathogen, and environmental factors influence Wolbachia density and how their interplay can impact CI and WMPB. We further review the strategies adopted to maintain/control Wolbachia densities in field populations.