Julián Fernández

Coral snakes of the American continent are classified into two genera, Micruroides and Micrurus, with as many as 91 species recognized in the latter. Although envenomings caused by Micrurus are rare, they can be life-threatening due to neurotoxic effects leading to flaccid paralysis and potential respiratory failure. Micrurus ancoralis is found in the Pacific lowlands and along the western slope of the cordillera occidental Cordillera in Colombia. Although this species is relatively common within its distribution range, its phylogenetic position and the characterization of its venom have not been investigated. The results of phylogenetic analysis placed M. ancoralis within the triadal/bicolor clade of species with the characteristic triad pattern and group bicolor. Proteomic characterization of the venom showed predominance of phospholipase A₂ (PLA₂) enzymes in its composition, with 51.7% of the total protein content, followed by three-finger toxins (3FTxs; 23.2%) and lower proportions of proteins belonging to several other minor families. Out of 28 chromatographic venom fractions obtained, the seven most abundant were evaluated for toxicity, with three of them (F7, identified as a 3FTx, and F18 and F20 (both identified as PLA₂s)) showing lethal activity by the intraperitoneal route in mice. The PLA₂ activity of F20 was confirmed and its edema-inducing, myotoxic, and lethal effects in mice were demonstrated. A therapeutic equine anti-coral antivenom (INS, Colombia) against coral snake envenomings immunorecognized the whole venom and its fractions in ELISA tests and was able to neutralize 2 × LD₅₀ (medial lethal dose) of M. ancoralis venom by preincubation, with an estimated potency of at least 0.2 mg venom/mL antivenom. This result suggests that envenomings by M. ancoralis could be effectively treated by this antivenom.

The scorpion Hottentotta judaicus inhabits the Levant region of the Middle East, including Lebanon, Jordan, Palestine, and Israel. While previous research focused on its insecticidal properties and sodium-channel-targeting toxins, its venom remains largely unexplored using modern proteomic approaches. We analyzed the venom composition of H. judaicus from Lebanese specimens using nESI-MS/MS, MALDI-TOF MS, SDS-PAGE, and RP-HPLC. Venom lethality in mice was assessed (LD₅₀ = 11.87 [6.59–17.16] mg/kg, i.p.), confirming moderate toxicity to vertebrates. RP-HPLC on C₁₈ resolved 37 peaks, with 25 eluting between 20–40% acetonitrile. Reducing SDS-PAGE revealed predominant components < 10 kDa and minor bands at 31, 46, and 77 kDa. MaLDI-TOF MS detected 20 components from 1,000–12,000 m/z. A bottom-up shotgun nLC-MS/MS approach, following in-gel tryptic digestion of venom, identified 55 components across 15 protein families. Ion channel-active toxins [K⁺ (7), Na⁺ (16), Cl⁻ (1), ryanodine receptor (1)] and enzyme components (17) were predominant. This study provides proteomic evidence of H. judaicus venom components previously only identified at the transcriptomic level and reveals a richer venom profile than anticipated. Novel identified components include alternative β-subunits of lipolysis-activating proteins, as well as homologs of Olivierus martensii antimicrobial peptide inhibitor HAP-1, Leiurus hebraeus Lqhβ1, Parabuthus transvaalicus Birtoxin, and peptide Hj2a from Hottentotta jayakari exhibiting dual α/β-toxin activity on Nav1.1 channels. This expanding repertoire of potential bioactive components prompts a reevaluation of the pathophysiological consequences of H. judaicus envenomation in humans and further exploration of their potential biomedical applications.

Snakebite is a high-priority neglected tropical disease, and a strategic goal based on four pillars has been recommended to reduce mortality and morbidity. One is empowering rural communities through citizen science, education, and engagement. In this study, an integrative approach was used to expand our knowledge of Micrurus nigrocinctus status and characterize its venom. Using citizen science data and field visits to local communities, 99 records of M. nigrocinctus distributed in Antioquia, Chocó, and Córdoba were obtained. Children, young people, and adults recognized M. nigrocinctus as the most common coral snake species in their region, and two specimens were recovered for venomic and Phylogenetic analyses. The M. nigrocinctus venom from Colombia exhibited similar chromatographic and electrophoretic profiles and biological activities and shared nearly identical protein families with Costa Rica. Commercial coral snake antivenoms also recognized and neutralized the whole venom from both countries. However, phylogenetic relationships showed greater divergence with specimens from Costa Rica. Involving communities helps prevent coral snake bites and facilitates access to rare specimens such as M. nigrocinctus, thereby enabling venom analyses, improving antivenom evaluation, and advancing toxinology research for medically significant species.

We report the biochemical and proteomic characterization of the venom of the arboreal Talamancan palm-pitviper, Bothriechis nubestris, a species endemic to north and central parts of the Costa Rican Cordillera de Talamanca, at 2100 to 3000 m above sea level. The Talamancan palm-pitviper venom arsenal comprised the translated products of 26 unique transcripts into 10 toxin classes, where metalloproteinases PIIa and PIII represent the dominant components. In vitro, the venom proteolyzed azocasein and gelatin but showed no phospholipase A₂ or human plasma coagulant activities. In vivo, B. nubestris venom exhibited an intravenous median lethal dose (LD₅₀) of 21.5 (95% confidence interval: 15.6-29.5) μg/mouse, and a minimum hemorrhagic dose (MHD) of 1.85 μg. PoliVal-ICP antivenom neutralized the venom's lethal activity with a potency of 9.7 mg of venom/g of antivenom and significantly reduced the hemorrhagic effect. Comparison of venom gland transcriptomes and venom proteomes of B. nubestris and its closest congeneric relative, B. nigroviridis, revealed that highly conserved venom gland transcriptomes are differentially processed by each species to produce divergent (type-I vs type-II, respectively) venoms. This phenomenon contributes to the remarkable venom phenotypic variability found across the palm-pitviper phylogeny. A possible mechanism for the occurrence of type-I/type-II venom phenotypic dichotomy is discussed.