Posts tagged biochemistry

Lower extremity of newborn, under running water for several months - formation of “adipocere” One of the most interesting things to find in a cadaver is when adipocere forms. This so-called “grave wax” shows that a body is at least several months old, as it takes a while for the biochemical reactions to take place that form this substance. While most cadavers go through the full decomposition process and are rotted away by bacteria and other organisms, bodies that form adipocere begin a process of anaerobic bacterial hydrolysis at the start of the putrefaction stage of decomposition. As most of the proteins in the body are digested, the fat in the body racidifies, and instead of being digested with everything else, breaks down into glycerine, fatty solids (saturated fats), and fluid fatty acids (unsaturated fat). The glycerine and fluid fatty acids are washed away or dissolved, and the solid fat remains behind, forming a cast of the body. Adipocere is white or gray, and very much like thick cottage cheese in its crumbly texture. It’s very hardy and preservative in quality, and cadavers over 700 years old have been found to have easily-discernible fine facial structures because of it. However, the formation of the substance requires very specific conditions to be met, the most important of which is a body with a relatively high fat content (though there are occasional exceptions). Because of this, infants, young women, and the obese are most likely to be found in this state. Atlas of Legal Medicine. Dr. Eduard von Hofmann, 1898.

Lower extremity of newborn, under running water for several months - formation of “adipocere”

One of the most interesting things to find in a cadaver is when adipocere forms. This so-called “grave wax” shows that a body is at least several months old, as it takes a while for the biochemical reactions to take place that form this substance.

While most cadavers go through the full decomposition process and are rotted away by bacteria and other organisms, bodies that form adipocere begin a process of anaerobic bacterial hydrolysis at the start of the putrefaction stage of decomposition. As most of the proteins in the body are digested, the fat in the body racidifies, and instead of being digested with everything else, breaks down into glycerine, fatty solids (saturated fats), and fluid fatty acids (unsaturated fat). The glycerine and fluid fatty acids are washed away or dissolved, and the solid fat remains behind, forming a cast of the body.

Adipocere is white or gray, and very much like thick cottage cheese in its crumbly texture. It’s very hardy and preservative in quality, and cadavers over 700 years old have been found to have easily-discernible fine facial structures because of it. However, the formation of the substance requires very specific conditions to be met, the most important of which is a body with a relatively high fat content (though there are occasional exceptions). Because of this, infants, young women, and the obese are most likely to be found in this state.

Atlas of Legal Medicine. Dr. Eduard von Hofmann, 1898.

Phospholipase A2 note:

[boring biochem technicalities]

Humans create their own PLA2 (I and II) that serve completely different functions than as a hemolytic enzyme (though an overload of PLA2 will act in that fashion). In fact, in general, they have a function more closely associated to neurotoxic venoms than hemotoxic ones - they typically bind to acetylcholine receptors and serve as a cholinergenic molecule. This is why some snakes utilize it in a fashion that causes a flaccid (limp) paralysis, including a failure of the diaphragm muscles to contract, leading to death by suffocation.

However, in some snakes (notably vipers and boomslangs), PLA2 is simply the primary protein in a cocktail of toxins that make up the venom. The other enzymes and molecules combine to create a potent hemotoxic venom that ruptures erythrocytes in a slow and steady manner, and get broken down by the body in an even slower manner.

[/boring biochem technicalities]

Hence, PLA2 in boomslangs = good lord you’re bleeding out your eyes and ears and mouth and nose and probably other places

Dyspholidus typus - The Boomslang Though it belongs to the same family as king snakes and the most common “grass snakes”, the boomslang is one of the few members of Colubridae to possess a venom that’s legitimately dangerous to humans, and the fangs that are able to inject it (some members of the family have venom, but weak fangs). In fact, the fangs of the boomslang are some of the broadest and most deeply-grooved in the snake world. The venom of the boomslang is hemotoxic. That means that the proteins in the venom affect the blood of the victim, and in the case of the most common hemotoxin in boomslang venom (phospholipase A2, if you’re wondering), it causes red blood cells to rupture. Given enough time with this toxin floating around in the bloodstream, the significant thinning of the blood allows it to flow out of the capillary walls, and can flow out of any part of the body where capillaries are particularly close to the exposed surface. In other words, if you’re bitten by a boomslang and don’t seek help right after being bitten, you’ll likely end up bleeding out from your nose, eyes, mouth, ears, and genital orifices. Because of the significant blood loss associated with a wait of more than 48 hours between bite and antivenin administration (phospholipases are fairly slow-working, compared to neurotoxins and cardiotoxins), full blood transfusions are sometimes needed, to replenish the plasma, red blood cells, and platelets that were lost in the bleed-out. Illustrations of the Zoology of South Africa. Andrew Smith, 1888.

Dyspholidus typus - The Boomslang

Though it belongs to the same family as king snakes and the most common “grass snakes”, the boomslang is one of the few members of Colubridae to possess a venom that’s legitimately dangerous to humans, and the fangs that are able to inject it (some members of the family have venom, but weak fangs). In fact, the fangs of the boomslang are some of the broadest and most deeply-grooved in the snake world.

The venom of the boomslang is hemotoxic. That means that the proteins in the venom affect the blood of the victim, and in the case of the most common hemotoxin in boomslang venom (phospholipase A2, if you’re wondering), it causes red blood cells to rupture. Given enough time with this toxin floating around in the bloodstream, the significant thinning of the blood allows it to flow out of the capillary walls, and can flow out of any part of the body where capillaries are particularly close to the exposed surface.

In other words, if you’re bitten by a boomslang and don’t seek help right after being bitten, you’ll likely end up bleeding out from your nose, eyes, mouth, ears, and genital orifices. Because of the significant blood loss associated with a wait of more than 48 hours between bite and antivenin administration (phospholipases are fairly slow-working, compared to neurotoxins and cardiotoxins), full blood transfusions are sometimes needed, to replenish the plasma, red blood cells, and platelets that were lost in the bleed-out.

Illustrations of the Zoology of South Africa. Andrew Smith, 1888.