“Caracterização bioquímica de peçonha e muco de Potamotrygon motoro”

Abstract

In Brazil, accidents involving venomous fish are becoming increasingly frequent, due to activities carried out in the water by riverside populations, such as fishing, washing clothes and utensils, as well as leisure activities. Stingrays are cartilaginous fish, present in both rivers and seas. They have a tail containing a sting, which is quickly inserted into the victim's body when accidental contact is made with their back. Accidents with freshwater stingrays can trigger a series of inflammatory reactions, as well as edema and dermonecrosis, due to the presence of toxins in the venom composition. Each of these components acts in a differentiated manner, resulting in myotoxic, neurotoxic activities, platelet aggregations, among others. Mucus is an unexplored source of antimicrobial peptides; studies have proven the existence of AMPs that present activities against pathogenic agents. The stingray Potamotrygon motoro occurs in the Paraná-Paraguay and Tocantins basins and it has a light brown dorsal coloration and bicolored ocelli. This work aimed at the biochemical characterization of the venom and mucus of the stingray Potamotrygon motoro. The stingrays used were donated by the Bioparque Pantanal. Different electrophoresis were performed in order to evaluate the protein profile of this species, including polyacrylamide gel electrophoresis (SDS-PAGE) and electrophoresis for low molecular weight proteins. In the extracts of the mucus and the sting, a band with a molecular mass of approximately 75 kDa was identified, similar to a 79 kDa band identified in another work with a hyaluronidase. Bands below 15 kDa can also be seen, in both the mucus and sting extracts suggesting peptides. Through HPLC analysis of the protein extract of the mucus, the presence of a hydrophilic compound, possibly a peptide (peak 1), was noted; this peak turned out to be predominant in the sample. Moreover, 8 less abundant peaks could be observed in the chromatographic profile of the protein extract of the mucus. This is the first work showing the chromatographic profile of Potamotrygon motoro. It can be observed that the protein profiles of the venom and mucus extracts are relatively similar, which suggests new studies to identify the reasons for the venom presenting a more severe worsening than the mucus