Reptile & Amphibian Forums

Greetings, while much of this is somewhat difficult to follow...[it'd be nice for Dr Fry or Wuster to give us an english translation] the effort is worth it. I think after my Clelia attempted to put a feeding bite on me yesterday...Id better heed the last paragraph & start using a hook!

Saludos, RxR

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=10858509&dopt=Citation

Toxicon. 2000 Dec;38(12):1663-87.

Characterization of venom (Duvernoy's secretion) from twelve species of colubrid snakes and partial sequence of four venom proteins.

Hill RE, Mackessy SP.

Department of Biological Sciences, 501 20th St., University of Northern Colorado, Greeley 80639-0017, USA.

R.E. Hill and S.P. Mackessy. Characterization of venom (Duvernoy's secretion) from twelve species of colubrid snakes and partial sequence of four venom proteins. Toxicon XX, xx-yy, 2000. - Venomous colubrids, which include more than 700 snake species worldwide, represent a vast potential source of novel biological compounds. The present study characterized venom (Duvernoy's gland secretion) collected from twelve species of opisthoglyphous (rear-fanged) colubrid snakes, an extremely diverse assemblage of non-venomous to highly venomous snakes. Most venoms displayed proteolytic activity (casein), though activity levels varied considerably. Low phosphodiesterase activity was detected in several venoms (Amphiesma stolata, Diadophis punctatus, Heterodon nasicus kennerlyi, H. n. nasicus and Thamnophis elegans vagrans), and acetylcholinesterase was found in Boiga irregularis saliva and venom, but no venoms displayed hyaluronidase, thrombin-like or kallikrein-like activities. High phospholipase A(2) (PLA(2)) activity was found in Trimorphodon biscutatus lambda venom, and moderate levels were detected in Boiga dendrophila and D. p. regalis venoms as well as B. dendrophila and H. n. nasicus salivas. Non-reducing SDS-PAGE revealed 7-20 protein bands (3.5 to over 200 kD, depending on species) for all venoms analyzed, and electrophoretic profiles of venoms were typically quite distinct from saliva profiles. Components from A. stolata, Hydrodynastes gigas, Tantilla nigriceps and T. e. vagrans venoms showed protease activity when run on gelatin zymogram gels. N-terminal protein sequences for three 26 kD venom components of three species (H. gigas, H. torquata, T. biscutatus) and one 3.5 kD component (T. nigriceps) were also obtained, and the 3.5 kD peptide showed apparent sequence homology with human vascular endothelial growth factor; these data represent the first sequences of colubrid venom components. Protease, phosphodiesterase and PLA(2) activities are also common to elapid and viperid snake venoms, but it is apparent that numerous other (as yet undescribed) components make up the majority of colubrid venom proteins. The complex nature of venoms produced by most species surveyed, and the high levels of protease or phospholipase A(2) activity of some venoms, suggest that many colubrids could become an important source of human health concern as encounters with these snakes increase.

MeSH Terms:
Acetylcholinesterase/analysis
Amino Acid Sequence
Animals
Colubridae*
Comparative Study
Elapid Venoms/chemistry
Electrophoresis
Electrophoresis, Polyacrylamide Gel
Endopeptidases/analysis
Exocrine Glands/secretion*
Human
Male
Molecular Sequence Data
Phospholipases A/analysis
Phosphoric Diester Hydrolases/analysis
Saliva/chemistry
Sequence Homology, Amino Acid
Snake Bites/pathology
Snake Venoms/chemistry*
Species Specificity
Support, U.S. Gov't, P.H.S.
Viper Venoms/chemistry

Substances:
Elapid Venoms
Snake Venoms
Viper Venoms
Phospholipases A
Acetylcholinesterase
Phosphoric Diester Hydrolases
Endopeptidases

Grant Support:
GM52665-01/GM/NIGMS

Basically, the study says that colubrid venoms have a complex composition with a multitude of components, and a wide range of activities. Some of these activities, such as phospholipase A2, are associated with toxins of clinical importance in other snakes, so keep your fingers out of their mouths

With the toxin phylogeny studies we have been doing, we now know why this is so, namely because all major colubrid lineages are descended from a common ancestor that already had a complex venom, with many of the major toxin families known from vipers and elapids, and many have retained this complexity to the present day, so keep your fingers out of their mouths

The Hill & Mackessy study was pretty much the first to look at the activities of a broad range of colubrid venoms, and those authors developed the methods that allow investigators to extract workable quantities of venom from colubrids, so it is in fact a pioneering piece of work.

Cheers,

Wolfgang
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Thankyou for the distillation professor, I for one am surprised to learn how complex these venoms are & how they apparently vary considerably between spps. I expected a short list of active enzymes w the bulk of venom volume being inactive fluids to facilitate their movement.
Interestingly too, having closely examined several of the NA opistoglyphs, I had already derived a working hypothesis that their are differences in toxicity between some of these snakes. Nice when behavioral observations and the biochemistry are in alignment!

Cheers, John Gunn