De novo venom gland transcriptomics of Calliophis bivirgata flaviceps: uncovering the complexity of toxins from the Malayan blue coral snake

The Malayan blue coral snake, Calliophis bivirgata flaviceps, is a medically important venomous snake in Southeast Asia. However, the complexity and diversity of its venom genes remain little explored. Methods: To address this, we applied high-throughput next-generation sequencing to profile the venom gland cDNA libraries of C. bivirgata flaviceps. The transcriptome was de novo assembled, followed by gene annotation, multiple sequence alignment and analyses of the transcripts. Results: A total of 74 non-redundant toxin-encoding genes from 16 protein families were identified, with 31 full-length toxin transcripts. Three-finger toxins (3FTx), primarily delta-neurotoxins and cardiotoxin-like/cytotoxin-like proteins, were the most diverse and abundantly expressed. The major 3FTx (Cb_FTX01 and Cb_FTX02) are highly similar to calliotoxin, a delta-neurotoxin previously reported in the venom of C. bivirgata. This study also revealed a conserved tyrosine residue at position 4 of the cardiotoxin-like/cytotoxin-like protein genes in the species. These variants, proposed as Y-type CTX-like proteins, are similar to the H-type CTX from cobras. The substitution is conservative though, preserving a less toxic form of elapid CTX-like protein, as indicated by the lack of venom cytotoxicity in previous laboratory and clinical findings. The ecological role of these toxins, however, remains unclear. The study also uncovered unique transcripts that belong to phospholipase A2 of Groups IA and IB, and snake venom metalloproteinases of PIII subclass, which show sequence variations from those of Asiatic elapids. Conclusion: The venom gland transcriptome of C. bivirgata flaviceps from Malaysia was de novo assembled and annotated. The diversity and expression profile of toxin genes provide insights into the biological and medical importance of the species.(AU)

Consumo de un pez por parte de la serpiente coral Micrurus alleni (Serpentes: Elapidae)en Costa Rica / A fish prey found in the coral snake Micrurus alleni (Serpentes: Elapidae)in Costa Rica

The presence of a small specimen of the swamp eel Synbranchus marmoratus (84 mm total length) in the stomach contents of an adult coral snake Micrurus alleni with 692 mm total length from the Caribbean versant of Costa Rica is reported.This eel was swallowed headfirst

Thyroid gland and tissue respiration in the fresh-water snake, Xenochrophis piscator (Serpentes, Colubridae)

Foi estudado o efeito da tireoidectomia e da L. tiroxina nas taxas de respiraçäo de tecidos relacionados (fígado, coraçäo, rim, músculo) da serpente de água doce, Xenochrophis piscator. A taxa de absorçäo de oxigênio variou nos diferentes tecidos. Um declínio significativo (p < 0,01) no consumo de oxigênio, ocorreu em todos os tecidos após a tireoidectomia, que foi recuperado pela terapia com L. tiroxina in vivo. A administraçäo de L-tiroxina ter efeito estimulador sobre o consumo de oxigênio. O tratamento com L-tiroxina in vivo também estimulou a taxa de respiraçäo tecidual, independentemente da condiçäo tireoideana do animal