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| Author(s): |
Vincent Louis Viala
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Pesquisas Energéticas e Nucleares (IPEN/BT) |
| Defense date: | 2014-05-26 |
| Examining board members: |
Patrick Jack Spencer;
Geraldo Santana Magalhães;
Nancy Oguiura;
Daniel Carvalho Pimenta;
Daniel Perez Vieira
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| Advisor: | Patrick Jack Spencer |
| Abstract | |
Snake venom toxins alter prey homeostasis for feeding or defense. In depth studies of venom composition are important for better antivenom production, for new drugs lead and discovery and for better understanding of biological, ecological and evolutionary processes. Research on toxins have shown the natures way of innovating, refined by evolution, diversifying functions of protein families recruited from their endogenous function to the venom gland by successive gene duplication and mutation accumulation, leading to an accelerated evolution. A myriad of available toxins and diversity of functions is still available for discovery. Combining high throughput techniques such as venom gland de novo transcriptomics and venom proteomics, one can assess and observe a more complete profile of the snake toxinome, additionally allowing an upscale in low represented and unexpected toxin detection. The aim of this project was to investigate the venom toxinome of one of the most dangerous Australian species, Pseudonaja textilis (Elapidae). The toxins identified in it venom was: protrombinase complex coagulation factors, neurotoxic textilotoxin phospholipase A2 (PLA2) subunits and procoagulant PLA2, neurotoxic three-finger toxins (3FTx), Kunitz-type protease inhibitor textilinin, and for the first time, a new long 3FTx, C-type lectins, CRiSPs, as well as evidences of lizard toxins from Heloderma genus and other toxin candidates calreticulin and dipeptidase 2. Metalloproteinases, little investigated in Elapidae, was cloned and detected in the venom after fractionation and immunoassay. The transcriptome revealed new toxin variants and isoforms, specially 3FTx and serine protease inhibitors, as well as transcripts from toxins not detected in the venom that deserves further investigation. Human accident symptoms are well explained by the identified toxins, however, in its natural environment, little known and undescribed toxins must have specific and important role in predation. Identifying this diversity is important to better understand toxins ways of action. (AU) | |
| FAPESP's process: | 09/10305-8 - Gene expression analysis in Pseudonaja textilis (Elapidae: Serpentes) venom glands. |
| Grantee: | Vincent Louis Viala |
| Support Opportunities: | Scholarships in Brazil - Doctorate |