Project description:Venoms are ecological innovations that have evolved numerous times, on each occasion accompanied by the co-evolution of specialised morphological and behavioural characters for venom production and delivery. The close evolutionary interdependence between these characters is exemplified by animals that control the composition of their secreted venom. This ability depends in part on the production of different toxins in different locations of the venom gland, which was recently documented in venomous snakes. Here, we test the hypothesis that the distinct spatial distributions of toxins in snake venom glands is an adaptation that enables the secretion of venoms with distinct ecological functions.
Project description:In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of its products, high-throughput expressed sequence tags were generated using Illumina paired-end sequencing technology. A total of 212,371,758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36,042 contigs for which 27,873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the reads mapping toxin class revealed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%) followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus). 300 ant specimens from the species Tetramorium bicarinatum were dissected in order to extract the RNA from their venom gland, The whole ant body was used as a reference,
Project description:In order to provide a global insight on the transcripts expressed in the venom gland of the Brazilian ant species Tetramorium bicarinatum and to unveil the potential of its products, high-throughput expressed sequence tags were generated using Illumina paired-end sequencing technology. A total of 212,371,758 pairs of quality-filtered, 100-base-pair Illumina reads were obtained. The de novo assemblies yielded 36,042 contigs for which 27,873 have at least one predicted ORF among which 59.77% produce significant hits in the available databases. The investigation of the reads mapping toxin class revealed a high diversification with the major part consistent with the classical hymenopteran venom protein signature represented by venom allergen (33.3%) followed by a diverse toxin-expression profile including several distinct isoforms of phospholipase A1 and A2, venom serine protease, hyaluronidase, protease inhibitor and secapin. Moreover, our results revealed for the first time the presence of toxin-like peptides that have been previously identified from unrelated venomous animals such as waprin-like (snakes) and agatoxins (spiders and conus).
Project description:To comprehend the drivers underlying venom variation in ants, we selected 15 Neotropical species and recorded a range of traits, including ecology, morphology, and venom bioactivity. Principal component analysis of both morphological and venom bioactivity traits revealed that stinging ants display two functional strategies. Additionally, phylogenetic comparative analysis indicated that venom function (predatory, defensive, or both) and mandible morphology significantly correlate with venom bioactivity and amount, while pain-inducing activity trades off with insect paralysis. Further analysis of the venom biochemistry of the 15 species revealed switches between cytotoxic and neurotoxic venom compositions in some species. This study highlights the fact that ant venoms are not homogenous, and for some species, there are major shifts in venom composition associated with the diversification of venom ecological functions.
Project description:Venoms are important evolutionary keys and innovation for several animal taxons., including snakes. Their use is specially related to feed, predation and defense. Snake venoms are composed mainly by free secreted proteins, about 98%, and stored in the lumen of the venom gland, where they are processed through poorly understood mechanisms. In the perspective of protein-diversity, venoms undergo evolutionary pressure which generate a rapid evolutionary response, causing a great diversity in their toxin-components. We know now that extracellular vesicles exist in snake venom, although their biological role are still unknown. We believe that understanding EV-mediated effects could change our way of seeing envenoming, especially long-term sequelae. From what we know about EVs and snake venoms, there is a lot of potential of cross-organism communication occurrence between snakes and human victims. To advance in the comprehension of venom EVs function, we used fresh B. jararaca venom as our model. Fresh venom was fractionated by sequential centrifugation, resulting in two populations of vesicles (Bj-EVs). Purified Bj-EVs were analyzed by electron microscopy, NTA and proteomics. The interaction of Bj-EVs with mammalian cells was accessed by fluorescence and electron microscopy.
Project description:Venoms are biochemical arsenals that have emerged in numerous animal lineages, where they have coevolved with morphological and behavioural traits for venom production and delivery. In centipedes, venom evolution is thought to be constrained by the morphological complexity of their venom glands due to physiological limitations on the number of toxins produced by their secretory cells. Here, we show that the uneven toxin expression that results from these limitations have enabled giant centipedes to regulate the composition of their secreted venom despite having morphologically undifferentiated venom glands. We show that this control is likely achieved by the complex neuronal networks that innervate each venom gland subunit and is facilitated by morphological adaptations that circumvent the physiological evolutionary constraints on venom production. Our results suggest behavioural control over venom composition may be an overlooked aspect of venom biology and provide an example of how exaptation can facilitate evolutionary innovation and novelty.
Project description:The Tibellus genus spider is an active hunter that does not spin webs and remains highly underinvestigated in terms of the venom composition. Here, we present a combination of venom glands transcriptome cDNA analysis, venom proteome analysis for unveiling of the Tibellus genus spider venom composition.