Moreover, a transcriptomic analysis of B.

granulifera was included to reveal new peptide sequence present in this sea anemone species. This is the first peptidomic and transcriptomic study of the neurotoxic fractions of these sea anemones, and the first report that compares the overall peptide composition of sea anemones species belonging to two distinct families (Stichodactylidae vs. Actiniidae). We found that the neurotoxic fraction of B. granulifera has richer peptide diversity in relation to S. helianthus, as judging by the more complex reversed-phase profile and the resulting higher number of separated peptide components (156 vs. 113 peptides) and toxic fractions (17 vs. 6). However a similar study of B. cangicum yielded a considerable smaller number of peptide components (81) than B. granulifera, despite both sea anemone species belong to the same genus and their chromatographic profiles share a similar complexity and several similarities, therefore see more such difference does not seem to arise from the use of different selleck screening library mucus extraction methods (immersion in distilled

water vs. electrical stimulation). Our study expanded to 156 the estimated maximal number of peptides in the neurotoxic fraction of sea anemones. We emphasize the term “maximal number” as we showed that venom peptide diversity varies among sea anemone species. Moreover, likewise the previous study [85] we found some apparent venom composition overlaps. Structural studies will confirm whether a single neurotoxic peptide is present in two or more sea anemone species. Peptide toxins previously isolated and characterized from S. helianthus and B. granulifera were identified in the present study, with the exception of ShK [14] and ShPI-1 [22]. These toxins seem to be poorly represented in the S. helianthus exudate so it was not possible to detect them by mass spectrometry. ShK occurs in very low amounts either in freeze-dried mucus or in whole Paclitaxel ic50 body extract [14], so its purification included a precipitation step by heating the sample at low pH, prior to the chromatographic protocol. Likewise, the isolation of

ShPI-1 comprised a precipitation step (trichloroacetic acid treatment) before the chromatographic separation which included affinity chromatography [22], utilized in many instances as a powerful purification method when the protein of interest is a minor component of a complex mixture [13]. Our study confirmed the presence of a very distinguishable feature among sea anemone species of the genus Bunodosoma, a group of abundant and hydrophobic 4–5 kDa peptides that elute in the last reversed-phase fractions ( Fig. 2 and Fig. 3), so far comprising type 1 sodium channels toxins and APETx-like peptides. The sodium channel toxins are BcIII from B. caissarum [55], Bcg 28.19 and Bcg 30.24 from B. cangicum, BgII and BgIII from B. granulifera. The APETx-like peptides are BcIV from B. caissarum [64], Bcg 31.16, Bcg 28.78, Bcg 25.