Search

Effect of anti-mosquito-fat body antibodies on the development of the malaria parasite, Plasmodium vivax has been studied by feeding Anopheles stephensi mosquitoes with infected blood supplemented with serum from immunized rabbits. Immunogenic polypeptides were identified by western blot. Mosquitoes that ingested anti-fat body antibodies along with infectious blood meal had significantly fewer oocysts than the mosquitoes in the control group. Effect of anti-mosquito fat body antibodies on fecundity, hatchability, mortality and engorgement of mosquitoes has also been reported. A significant reduction in fecundity and hatchability was observed, however, effect on mortality and engorgement was variable and statistically insignificant. Results indicated that fat body antibodies have the potential to disrupt reproductive physiology of malaria vector An. stephensi.

Insulin signaling is a conserved pathway in all metazoans. This pathway contributed toward primordial metazoans responding to a greater diversity of environmental signals by modulating nutritional storage, reproduction, and longevity. Most of our knowledge of insulin signaling in insects comes from the vinegar fly, Drosophila melanogaster , where it has been extensively studied and shown to control several physiological processes. Mosquitoes are the most important vectors of human disease in the world and their control constitutes a significant area of research. Recent studies have shown the importance of insulin signaling in multiple physiological processes such as reproduction, innate immunity, lifespan, and vectorial capacity in mosquitoes. Although insulin-like peptides have been identified and functionally characterized from many mosquito species, a comprehensive review of this pathway in mosquitoes is needed. To fill this gap, our review provides up-to-date knowledge of this subfield. [ABSTRACT FROM AUTHOR]

Simple Summary: Human malaria is transmitted by mosquitoes in the genus Anopheles—particularly species that prefer to feed on humans. The mosquito's sense of smell drives this preference; however, most studies have focused on species native to Sub-Saharan Africa. Malaria vectors in other parts of the world may use different odorants to choose hosts. We, therefore, focused on Anopheles stephensi, the south Asian malaria mosquito, in this study. Mosquitoes have different organs specialized for odor perception, such as the antennae; however, we focused on the mouthparts (primarily the maxillary palp and labella) in this study. We used the RNAseq technique to determine which odor receptors are present in the mouthparts and then focused on one of these receptors: Or8. Using a technique known as the Drosophila empty neuron system, we tested this receptor's ability to detect different odorants, particularly chemicals emitted by humans. This receptor in An. stephensi detected similar odors to a homologous receptor in an African species, Anopheles gambiae, with the exception of the chemical sulcatone. This chemical is an important attractant in other disease-transmitting mosquitoes and suggests that different mosquito species may be using odors differently to find hosts. Several mosquito species within the genus Anopheles are vectors for human malaria, and the spread of this disease is driven by the propensity of certain species to feed preferentially on humans. The study of olfaction in mosquitoes is important to understand dynamics of host-seeking and host-selection; however, the majority of these studies focus on Anopheles gambiae or An. coluzzii, both vectors of malaria in Sub-Saharan Africa. Other malaria vectors may recognize different chemical cues from potential hosts; therefore, in this study, we investigated An. stephensi, the south Asian malaria mosquito. We specifically focused on the mouthparts (primarily the maxillary palp and labella) that have been much less investigated compared to the antennae but are also important for host-seeking. To provide a broad view of chemoreceptor expression, RNAseq was used to examine the transcriptomes from the mouthparts of host-seeking females, blood-fed females, and males. Notably, AsOr8 had a high transcript abundance in all transcriptomes and was, therefore, cloned and expressed in the Drosophila empty neuron system. This permitted characterization with a panel of odorants that were selected, in part, for their presence in the human odor profile. The responsiveness of AsOr8 to odorants was highly similar to An. gambiae Or8 (AgOr8), except for sulcatone, which was detected by AsOr8 but not AgOr8. Subtle differences in the receptor sensitivity to specific odorants may provide clues to species- or strain-specific approaches to host-seeking and host selection. Further exploration of the profile of An. stephensi chemosensory proteins may yield a better understanding of how different malaria vectors navigate host-finding and host-choice. [ABSTRACT FROM AUTHOR]