All three P. elegans venoms containedPe_comp47_c

Gies are unknown. All three P. elegans venoms containedPe_comp47_c0_seq1, but none of the P. flavoviridis PLA2s. Likewise, all three P. flavoviridis venoms contained the three Pf PLA2s, but not Pe comp47_c0_ seq1. The hybrids, however, produced all five PLA2s from both parental species (Fig 3; Fig. 2; Additional file 6: Figure S5). Protobothrops elegans venom apparently has no neurotoxic PLA2s, but P. flavoviridis comp48_c0_seq1, which encodes a weak presynaptic neurotoxin similar to trimucrotoxin [63], comprised 6.3 of the P. flavoviridis transcriptome. Although some neurotoxic PLA2s are also myotoxic [64, 65], myotoxicity appears to be much more important for P. elegans than for P. flavoviridis. Nonetheless, it is difficult to offer an ecological explanation for this difference. In general, myotoxicity seems to be most often associated with mammal predation by large terrestrial crotalines [66?8], but it has also been reported in small arboreal species [69]. Without appropriate pharmacological studies in native prey species as well as laboratory animals, it is impossible to know whether such differences are adaptive or ecologically irrelevant. It may be that some subsets of myotoxic PLA2s are specifically adapted to reptilian rather than mammalian skeletal muscle, but if so, PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/12027669 the structural determinants are currently unknown. Relative to PLA2s, one other matter deserves mention. The P. elegans PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/20460822 cDNA library contains a peculiar transcript, Pe_comp103_c0_seq1, that represented 0.2 of the transcriptome (Additional file 2: Table S1). Using the Frame 3 reverse translation of comp103_c0_seq1, BLASTP and TBLASTX searches both suggested that the best match is a PLA2 gene cluster from P. flavoviridis (in Frame 1) [70]. However, both sequences are liberally punctuated with stop codons, and the longest, unbroken, translated segment of the P. elegans transcript, using Frame 1, encodes only 45 amino acids, or 3-O-Isopropylidene-D-ribono-1 about 37 of a typical Type II PLA2. BLASTP and pfam searches for the 45-residue protein yielded no results. However, mass spectrometry (R)-1-(3-Chlorophenyl)ethan-1-ol of the eight venoms detected three peptides (a total of 46 times) that cover 55.8 of the putative protein translated in Frame 1 (Fig 3). Further analysis of these peptides was done using de-novo sequencing algorithms and manual annotation, in order to confirm their identity (Additional file 7: Figure S2). This protein was not only detected in (S)-tert-Butyl 6-(hydroxymethyl)-5-azaspiro[2.4]heptane-5-carboxylate all three specimens of P. elegans; it was also detected in both hybrid venoms (Fig 3). Clearly, the snakes are producing this, but it does not appear to be a PLA2 derivative, the TBLASTX searches notwithstanding. Its function, assuming that it has one, is unknown.Serine proteasesIn both transcriptomes, serine proteases (SPs) are the second most abundant protein family (Table 1). Six SPs comprise 10.4 of all P. elegans transcripts, whereas eight represent 11.8 of all P. flavoviridis transcripts.Aird et al. BMC Genomics (2015) 16:Page 6 ofABFig. 2 Protobothrops flavoviridis x P. elegans hybrids express phospholipases A2 from both parental venoms. a Aligned PLA2 transcripts from P. flavoviridis and P. elegans transcriptomes. The solid heavy vertical line separates the signal peptides from the expressed PLA2s. A noncatalytic, myotoxic PLA2 transcript (comp43_c0_seq1) from P. elegans specimen #3 accounted for 73.4 of all P. elegans transcripts (Additional file 2: Table S1). This protein was heavily expressed in all three specimens and in both hybrids (Fig 3). A homo.