Saliva of blood-sucking arthropods contains a complex and diverse mixture of antihemostatic, antiinflammatory, and immunomodulatory compounds. The D7 salivary family of proteins is abundantly expressed in blood-feeding Diptera and is distantly related to the odorant-binding protein superfamily. In mosquitoes, two subfamilies exist, the long and short D7 proteins. Ticks and kissing bugs evolved salivary lipocalins that act as efficient scavengers of biogenic amines, and a similar function was postulated for the D7 proteins. Accordingly, we expressed the five members of the small D7 family of the African malaria vector Anopheles gambiae and a D7 long form from Aedes aegypti and showed by isothermal microcalorimetry, a modified and very sensitive non-equilibrium chromatography/spectrum distortion method, and by smooth muscle bioassay that four of these five short D7 proteins and the D7 long form bind serotonin with high affinity, as well as histamine and norepinephrine. The nonbinding D7 protein is poorly expressed in the salivary glands and appears to be on the path to becoming a pseudogene. Scavenging of host amines would antagonize their vasoconstrictor, platelet-aggregating, and pain-inducing properties. It appears that counteracting biogenic amines is of strong adaptive value in the convergent evolution of arthropods to hematophagy. This adaptation has been solved independently in ticks, bugs, and mosquitoes by co-option of either member of the lipocalin or, as shown here, by the odorant-binding protein families.At least 14 orders or families of arthropods (containing over 400 different genera and more than 15,000 species) independently evolved to feed on vertebrate blood (1). To accomplish this task, these animals evolved sophisticated cocktails of salivary pharmacologic reagents that affect blood clotting, platelet aggregation, vascular contraction, host immunity, inflammation, and angiogenesis. With the development of transcriptome analysis, the salivary compositional diversity of several hematophagous arthropods is being revealed at a fast pace; however, the majority of these proteins have no known function (2).Among many different families of proteins unique to hematophagous arthropods, the D7 family has been recognized to be specifically expressed in the salivary glands of adult Diptera. These proteins are distant relatives of the odorant-binding protein superfamily, of which they are a distinct branch. In mosquitoes, two D7 subfamilies exist, the short family having molecular mass of 15-20 kDa and the long with 27-30 kDa, whereas sand flies appear to have only the long forms (3-5). According to a recent sialotranscriptome analysis, Anopheles gambiae, the main African malaria vector, has three long and five short D7 proteins in chromosome arm 3R (6), arranged in an inverted tandem repeat. In the closely related mosquito Anopheles stephensi, one short D7 protein, named hamadarin, has been expressed and shown to have anticlotting activity (7). No other function has been described for the other protein memb...
Background: Saliva of blood-sucking arthropods contains a cocktail of antihemostatic agents and immunomodulators that help blood feeding. Mosquitoes additionally feed on sugar meals and have specialized regions of their glands containing glycosidases and antimicrobials that might help control bacterial growth in the ingested meals. To expand our knowledge on the salivary cocktail of AEdes aegypti, a vector of dengue and yellow fevers, we analyzed a set of 4,232 expressed sequence tags from cDNA libraries of adult female mosquitoes.
Graphical AbstractHighlights d Human malaria parasites interact non-competitively with their mosquito vectors d Mosquito hormone signaling co-regulates egg and parasite development d Parasites use host lipids for their growth via a mosquito lipid transporter d Parasites respond to mosquito metabolism with consequences for vector controlThe development of the malaria-causing parasite Plasmodium falciparum depends on its ability to exploit the sexual cycle of its mosquito host in a noncompetitive manner. SUMMARYTransmission of malaria parasites occurs when a female Anopheles mosquito feeds on an infected host to acquire nutrients for egg development. How parasites are affected by oogenetic processes, principally orchestrated by the steroid hormone 20hydroxyecdysone (20E), remains largely unknown.Here we show that Plasmodium falciparum development is intimately but not competitively linked to processes shaping Anopheles gambiae reproduction. We unveil a 20E-mediated positive correlation between egg and oocyst numbers; impairing oogenesis by multiple 20E manipulations decreases parasite intensities. These manipulations, however, accelerate Plasmodium growth rates, allowing sporozoites to become infectious sooner. Parasites exploit mosquito lipids for faster growth, but they do so without further affecting egg development. These results suggest that P. falciparum has adopted a non-competitive evolutionary strategy of resource exploitation to optimize transmission while minimizing fitness costs to its mosquito vector. Our findings have profound implications for currently proposed control strategies aimed at suppressing mosquito populations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.