Snakebite.

The five families of poisonous snakes are: Viperidae, elapidae, colubridae, hydrophidae, atractaspididae. The commonly seen snakes in India are saw scaled viper, Russell's viper, common cobri and common crait. The venom of a single snake contains all the toxins. The venom of viperidae is haemotoxic. It may complicate with acute renal failure if left untreated. The venom of elapidae is neurotoxic. Management consists in two parts-general and specific. Supportive treatment is done with the use of antibiotics and tetanus immunoglobulin/toxoid. Specific therapy for viper bite is elaborated in this article. Elapid bite and hydrophidae bites are also discussed. Prevention of snakebite is done with avoidance of contact with a snake by using protective knee length footwear and thick gloves. Venom toxoids are used for secondary prevention among the farmers of Japan.

Phospholipases A2: a dendrogram from a distance matrix based on size and hydrophobicity of the residues in their homologous sequences

A distance matrix was obtained from aligned homologous sequences of 32 phospholipases A2 (EC 3.1.1.4) (24 from Elapid and 5 from Viperid venoms, and 3 from amammals), on the basis of the quantities Dij which are defined from a two-dimensional vector representation of the amino acid residues (dimensions: size and hydrophobicity). These Dij quantities were proposed in a previous paper (Ventura, M.M., (1989), An. Acad. brasil. Ci., 61:215). A dendrogram was constructed from this distance matrix empoying, for cluster analysis, the unweighted pair-group using arithmetic averages. Two groups of phospholipases A2: a) Elapid venom enzymes together with the three mammalian pancreatic enzymes (bovine, equine and porcine), and b) Viper venom enzymes (Crotalus, Trimeresurus and Bitis enzymes) can be well distinguished in the topology of the dendrogram. The Elapid group of enzymes in divided into two subgroups: a) Naja, Hemachatus and Bungarus venom enzymes, and b) Notechis, Laticauda, Enhydrina pancreatic phospholipases A2 and the enzymes from Naja, Hemachatus and Bungarus. These results are similar to those reported by Dufton and Hider (Eur. J. Biochem., 137:545 (1983)) which were obtained from the distance matrix based on minimum mutation distance between 25 selected residue positions in the pairwise compared sequences

Limited proteolysis of human and rabbit immunoglobulins by snake venoms produces Fab-like fragments

Rabbit and, to a lesser extent, human immunoglobulins (IgGs) are cleaved by snake venoms. The snake venom proteases active on IgGs release fragments which behave on SDS-PAGE like Fab units similar to those release by the thiol-activated enzymes. However, in contrast to the cysteine proteases, the activity of snake venom proteases on IgGs is not only blocked by metal chelating agents but is also inhibited by thiol compounds. The snake enzymes active on IgG are metalloproteases