BIOLOGICAL SIGNIFICANCE: The Javan spitting cobra, Naja sputatrix is by itself a unique species and should not be confused as the equatorial and the Indochinese spitting cobras. The distinction among the spitting cobras was however unclear prior to the revision of cobra systematics in the mid-90's, and results of some earlier studies are now questionable as to which species was implicated back then. The current study successfully profiled the venom proteome of authenticated N. sputatrix, and showed that the venom is made up of approximately 64% three-finger toxins (including neurotoxins and cytotoxins) and 31% phospholipases A2 by total venom proteins. The findings verified that the paralyzing components in the venom i.e. neurotoxins are predominantly the short-chain subtype (SNTX) far exceeding the long-chain subtype (LNTX) which is more abundant in the venoms of monocled cobra and Indian common cobra. The neurotoxicity of N. sputatrix venom is hence almost exclusively SNTX-driven, and effective neutralization of the SNTX is the key to early reversal of paralysis. Unfortunately, as shown through a toxin-specific assay, the immunological neutralization of the SNTX using the Indonesian antivenom (SABU) was extremely weak, implying that SABU has limited therapeutic efficacy in treating N. sputatrix envenomation clinically. From the practical standpoint, actions need to be taken at all levels from laboratory to production and policy making to ensure that the shortcoming is overcome.

BIOLOGICAL SIGNIFICANCE: Laticauda colubrina (yellow-lipped sea krait) is a widely distributed, semi-aquatic venomous snake species. The venom proteome at the level of protein family is unsophisticated and consistent with its restricted prey selection. Nonetheless, the subproteomic findings revealed geographical variability of the venom for this widely distributed species. In contrast to two previous reports, the results for the Balinese L. colubrina venom showed that LNTX Neurotoxin a and Neurotoxin b were co-existent while the PLA2 lethal subtype (PLA-II) was undetected by means of LCMS/MS and by in vivo assay. This is an observable trait of L. colubrina considered divergent from specimens previously studied for the Philippines and the Solomon Islands. The stark geographical variation might be reflective of trophic adaptation following evolutionary arms race between the snake and the prey (eels) in different localities. The preferred trait would likely propagate and remain significant within the geographical population, since the strong behaviour of site fidelity in the species would have minimized gene flow between distant populations. Meanwhile, the in vivo neutralization study verified that the efficacy of the heterologous Sea Snake Antivenom (Australian product) is attributable to the cross-neutralization of SNTX and LNTX, two principal lethal toxins that made up the bulk of L. colubrina venom proteins. The findings also implied that L. colubrina, though could be evolutionarily more related to the terrestrial elapids, has evolved a much streamlined, neurotoxin- and PLA2-predominated venom arsenal, with major antigenicity shared among the true sea snakes and the Australo-Papuan elapids. The findings enrich our current understanding of the complexity of L. colubrina venom and the neutralizing spectrum of antivenom against the principal toxins from this unique elapid lineage.

CONCLUSION: The findings from this study suggest that excessive sun exposure is a risk factor for prostate cancer in Asians.