Preliminary report on the hemagglutinating activity of the Scorpaena plumieri fish venom.

The scorpionfish Scorpaena plumieri is one of the most venomous fish species in the Brazilian coast. Amongst many biological activities, the S. plumieri fish venom (SpV) promotes hemagglutination. Although this activity appears to be associated to the presence of C-type lectins in the venom, it has not yet been chemically or functionally characterized. In the present work we sought to advance the characterization of the hemagglutinating activity associated to this venom. By fractionating SpV through saline precipitation followed by size exclusion chromatography we obtained two purified fractions - HF1 and HF3 - with Ca2+-dependent agglutinating activity against rabbit erythrocytes, which remained stable upon storage at 4 and -80oC. HF1 and HF3 were bacteriostatic against Gram-positive bacteria (Staphylococcus aureus), displaying minimum inhibitory concentration (MIC) of 50 and 200 µg/mL, respectively. In addition, a resazurin-based viability assay revealed that both fractions, at doses up to 370 µg/mL, were cytotoxic against tumor and non-tumor cell lines. Finally, a tendency towards edema formation could be detected when the fractions - particularly HF1 - were injected into mice footpads. We believe our data contribute to a better understanding of the biological properties of the so often neglected fish venoms.

Combined proteomic and functional analysis reveals rich sources of protein diversity in skin mucus and venom from the Scorpaena plumieri fish.

The biological activities observed upon envenomation by Scorpaena plumieri could be linked to both the venom and the skin mucus. Through a proteomic/functional approach we analyzed protein composition and biological activities of the venom and skin mucus. We identified 885 proteins: 722 in the Venomous Apparatus extracts (Sp-VAe) and 391 in the Skin Mucus extract (Sp-SMe), with 494 found exclusively in Sp-VAe, being named S. plumieri Venom Proteins (Sp-VP), while 228 were found in both extracts. The majority of the many proteins identified were not directly related to the biological activities reported here. Nevertheless, some were classified as toxins/potentially interesting molecules: lectins, proteases and protease inhibitors were detected in both extracts, while the pore-forming toxin and hyaluronidase were associated with Sp-VP. Proteolytic and anti-microbial activities were linked to both extracts, while the main toxic activities - cardiovascular, inflammatory, hemolytic and nociceptive - were elicited only by Sp-VAe. Our study provided a clear picture on the composition of the skin mucus and the venom. We also show that the classic effects observed upon envenomation are produced by molecules from the venomous gland. Our results add to the growing catalogue of scorpaeniform fish venoms and their skin mucus proteins. SIGNIFICANCE: In this study a large number of proteins - including classical and non-classical toxins - were identified in the venomous apparatus and the skin mucus extracts of the Scorpaena plumieri fish through shotgun proteomic approach. It was shown that the toxic effects observed upon envenomation are elicited by molecules originated from the venomous gland. These results add to the growing catalogue of scorpaeniform fish venoms and their skin mucus proteins - so scarcely explored when compared to the venoms and bioactive components of terrestrial animals. Data are available via ProteomeXchange with identifier PXD009983.