(500-7900 characters long) Vector arthropods, such as mosquitoes, triatomine bugs and ticks, salivate while they puncture our skin in their search of blood. This saliva contains dozens to hundreds of compounds that have anti-clotting, anti-platelet, vasodilatory, anti-inflammatory, and immunomodullatory functions. While helping the vector to feed, it also modifies the site where pathogens are injected and in many cases facilitates the infection process. For this reason, salivary proteins of vectors can be used as vaccine targets for the diseases they transmit. Salivary proteins can also be used as immuno-epidemiological markers of vector exposure, and in themselves can have potent and novel pharmacological activities. Because the saliva of hematophagous animals is under attack of their host's immune system, their constituents are under a rapid evolutionary pressure in an arms'race scenario with their hosts, causing an enormous variety of unique protein families even in closely related organisms. The section of vector biology aims at uncovering the biodiversity of salivary proteins in the near 500 genera of blood sucking arthropods, and to discover the function of the novel protein families that we encounter. Accordingly we have developed a two pronged approach focusing in sialotranscriptome discovery projects and functional sialomic studies. In addition to these core studies on the saliva of vector arthropods, the section also collaborated with other members of the LMVR and other extramural scientists lending its expertise in bioinformatics, structural biology and vascular biology. Dr. Ribeiro's interest in vector ecology also led to continuing work on the ecology of malaria vectors in Africa. In the current fiscal year (2013), members of the Section of Vector Biology contributed to a total of 14 papers and 1 patent application. Sialotranscriptome discovery projects: Because host hemostasis (the physiological process that prevents blood loss, consisting of platelet aggregation, blood clotting and vasoconstriction) is a complex and redundant phenomenon, the salivary glands of blood sucking arthropods consist of a magic potion with diverse chemicals that in a redundant way counteract host mechanisms to prevent blood loss, allowing the fast acquisition of a meal. Salivary transcriptome made in the past few years indicate that the magic potion consists of 70-100 different proteins in the case of mosquitoes, for example, to over 1,000 in the case of ticks (Ticks feed for several days and have to disarm host immune reactions, in addition to the hemostatic system). Transcriptome studies also show that the salivary proteins of blood sucking arthropods are at a very fast pace of evolution, perhaps explaining why every genera studied so far has several unique protein families. Indeed there are unique proteins found at the subgenus level. Given we can now describe in detail the sialotranscriptome (from the Greek word sialo = saliva) of a single organism, we can ask now what is the universe of salivary proteins associated to blood feeding, the so called sialoverse. There are near 19,000 species of blood sucking arthropods in 500 different genera. If we find (minimally) 5 novel protein families per genus (within the 70-500 proteins in each sialome), there are at least 2,500 novel proteins to be discovered, each one with an interesting pharmacological property. We have so far explored less than 20 genera of blood sucking arthropods, and it is our goal to extend sialotranscriptome discovery to map this pharmacological mine for future studies, and in the process learn the paths taken by genomes in their evolution to blood feeding, and identify proteins with pharmacological and vaccine potential. In the current fiscal years, we produced four papers related to sialotranscriptome discovery, including two for sand fly vectors of Leishmaniasis (1-2), in collaboration with Dr. Jesus Valenzuela, one for the cat flea (3) and one from the vampire bat Desmodus rotundus, a vector of rabies (4). Novel protein families were discovered in fleas and vampire bats. Functional studies: We advanced our knowledge regarding the function of vector salivary proteins as reported in 2 publications, one describing a novel function for a member of the salivary antigen 5 family (5) and another describing the crystal structure of an anti-inflammatory protein from a triatomine bug (6). We have also collaborated in the functional identification of glycoinositol-phospholipids from Trypanosoma cruzi, the causative agent of Chagas disease (7). Bioinformatic collaborations: Dr. Ribeiro collaborated with intra and extra mural investigators lending his expertise in bioinformatics, helping to functionally characterize and annotate the genomes of a parasitic worm (8) and the main malaria vector of South America (9), the sex-pheromone gland transcriptome of a sand fly vector of leishmaniasis (10), the male accessory gland sexual transcriptome of a fruit fly (11), and the expression of virulence genes in Plasmodium falciparum (12), the main malaria pathogen. Vector ecology Studies related to Anopheles gambiae swarming were concluded, describing the dance of male mosquitoes (13) as well as a methodological approach to quantify stereoscopy videos of mosquitoes flying at twilight (14). Patent application: Dr. Francischetti submitted a patent application for an anticoagulant discovered in a black fly (15).
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