Venom of snake

Borreria verticillata (L) G. F. Mey. Eyeyel Venom of snake (L or R) Parts mashed or powder... 

Ritchiea capparoides (Andr.) Britt. Gabuuful Venom of snake (L) Mashed leaves... 

Zootoxin a toxin or poison of animal origin such as the venom of snakes, spiders, and scorpions. 

The phosphatidases A are carboxy-esterases by their specificity They are mainly found in the venom of snakes and bees. The products of the enzymic action are the lysoUdthins, so called because they hcmolyze erythrocytes. It was once believed that the poisonous quality of the venoms could be traced to that effect, but snake venom also contains other toxic substances without phos-phatidase activity, Phosphatidase B splits off both fatty acids. Both phosphatidase C (from plants) and D (from gas-gangrene bacilli) are classified as phosphodiesterases. 

Other Lethal Agents. There are a number of substances, many found in nature, which are known to be more toxic than nerve agents (6). None has been weaponized. Examples of these toxic natural products include shellfish poison, isolated from toxic clams puffer fish poison, isolated from the viscera of the puffer fish the active principle of curare "heart poisons" of the digitaUs type the active principle of the sea cucumber active principles of snake venom and the protein ricin, obtained from castor beans (See Castor oil). 

The venoms of poisonous snakes contain (among other things) a class of enzymes known as phospholipases, enzymes that cause the breakdown of phospholipids. For example, the venoms of the eastern diamondback rattlesnake (Crotalus adamanteus) and the Indian cobra Naja naja) both contain phospholipase Ag, which catalyzes the hydrolysis of fatty acids at the C-2 position of glyc-erophospholipids. 

Turning now to chemical attack, many predators immobilize their prey by injecting toxins, often neurotoxins, into them. Examples include venomous snakes, spiders, and scorpions. Some spider toxins (Quick and Usherwood 1990 Figure 1.3) are neurotoxic through antagonistic action upon glutamate receptors. The venom of some scorpions contains polypeptide neurotoxins that bind to the sodium channel. 

Phospholipase A activity was subsequently demonstrated to be present in venom, and it too required Ca (25). DEAE-cellulose fractionation yielded four proteins, two of which were phospholipase A and hemolytic, and two of which had neither phospholipase A nor hemolytic activities. Either of the latter two proteins enhanced to various degrees the hemolytic activity of either of the two phospholipases. The findings suggest considerable analogy with synergistic mechanisms underlying the hemolytic action of the venoms of a number of snakes. 

There are many venomous marine vertebrates in the seas, notably sea snakes and fishes. Venoms of sea snakes have been studied much more thoroughly than fish venoms. In this chapter, sea snake venom is described in greater detail than fish venoms simply because there is much more scientific information available. 

All sea snakes are poisonous and their venoms are extremely toxic. The LD q for crude sea snake venom can be as low as 0.10 fig/g mouse body weight (i). For purified toxin the LD q is even lower, suggesting the high toxicity of sea snake toxins and venoms. This toxicity is derived from the presence of potent neurotoxins. Compared to snake venoms of terrestrial origin, sea snake venoms have been studied less. Different enzymes reported to be present or absent are summarized in Table I. 

Similarity of venoms among different sea snakes and Elapidae can also be detected immunologically. For instance, the antibody for Enhydrina schistosa showed cross reactivity with the venoms of Hydrophis cyanocinctus, Lapemis hardwickii, and Pelamis platurus 12). The sea snake antivenin not only neutralizes the toxicity of various sea snake venoms, but also Naja naja atra (Taiwan cobra) venom 13-16). The reverse is also true namely, some Elapidae antivenins are also effective for neutralizing sea snake venom lethality 17-19). 

Since sea snake venoms are discussed here, it is appropriate to review other vertebrate venoms also. Unfortunately, very few investigations have been done on the venoms of other marine vertebrates. It is known that some fish secrete venoms from their spines. The fishes known to have venoms are the scorpion fish (family Scorpaenidae), weever fish (family Trachinidae), catfish (order Siluriformes there are 31 families), stargazers (family Uranoscopidae), toad fish (family Batrachoidi-dae), and stingrays (suborder Myliobatoidea). 

Direct Fibrinolytics Alfimeprase is a recombinant tmncated form of fibrolase, a fibrinolytic zinc metalloproteinase isolated from the venom of the Southern copperhead snake. It degrades fibrin directly and achieves thrombolysis independent of plasmin formation. This may result in faster recanalization and a decreased risk of hemorrhagic conversion. The initial data on the safety and efficacy of alfimeprase in peripheral arterial occlusion disease appeared very promising, but recent communication from the sponsor revealed that the phase III trials of the drug in peripheral arterial disease and catheter obstruction (NAPA-2 and SONOMA-2) failed to meet their primary and key secondary endpoints of revascularization. A trial for I AT in acute stroke (CARNEROS-1) is planned to begin soon. 

Venoms, nemoactive snake, 21 (1984) 63 Virtual screemng of virtual libraries, 41 (2003) 61... 

Neurotoxin obtained from the venom of the Australian taipan snake. 

From an entirely different source, namely, the venom of the snake Bothrops iararaca, scientists at Squibb isolated a nonapeptide (SQ 20,881, LXXI) which is a potent inhibitor of the converting enzyme (99). 

One of the hrst angiotensin converting enzyme (ACE) inhibitors was teprotide. It is an antihypertensive drug for use after heart attacks. The active ingredient was isolated from the venom of a South American viper snake. Other well-known ACE inhibitors such as captopril and analopril were developed based on modifications to the venom chemical structures. 

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