Crystalization Detoxifies Heme

Biological Strategy

Plasmodium falciparum

AskNature Team

Protect From Chemicals

Chemicals are everywhere in the bodies of living organisms and their external environments. While most chemicals are valuable or benign, some are toxic, including those used for defense (such as the mucus that protects clownfish from an anemone’s stinging tentacles). Even naturally-occurring chemicals, such as arsenic, must be managed to reduce their impact. Some living systems have strategies to break down harmful chemicals, alter them into less toxic forms, physically prevent chemicals from harming sensitive tissues, and more. For example, some herbivorous mammals can digest toxic compounds in plants because they have a particular enzyme that helps them process poisonous plant compounds.

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Chemically Assemble Mineral Crystals

The vast majority of biochemical assembly and break down processes––even by the most complex organisms––occur within cells. In fact, cells are able to perform hundreds, even thousands, of chemical transformations at the same time under life-friendly conditions (ambient temperature and pressure in an aqueous environment). Within cells, organisms utilize organic compounds to facilitate the assembly of mineral crystals. For example, oysters utilize acidic proteins and sulfated polysaccharides to assemble layers of aragonite crystals.

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Protists

Kingdom Protista (“the very first”): slime molds, giant kelp, red and brown algae

Protists are a numerous, diverse group of organisms that, in the simplest definition, are defined by what they are not. Protists are not plants, animals, fungi, or bacteria. Some protists, like Plasmodium, are harmful parasites that cause malaria. While many are small, obscure, and go unnoticed, others are important foodstuffs. The largest protist in the world, giant kelp (Macrocystis pyrifera), is utilized by humans and marine species for food and shelter.

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The malaria parasite, Plasmodium falciparum, detoxifies heme generated from digestion of its host's blood by coalescing the toxin into a harmless crystal.

Mosquitoes are responsible for spreading malaria, a protozoan disease that kills nearly one million people annually. But the risk actually runs both ways. That is, every time the mosquito bites its victim, it puts itself at risk from exposure to the iron-containing part of red blood cells, called heme, which is generated as a byproduct of blood digestion and toxic to the mosquito. The parasite, Plasmodium falciparum, sidesteps toxic exposure by binding free hemes together into an insoluble crystal structure. It does so by forming microscopic drops of oil into which free heme self assembles into crystal pairs (dimers) which then coalesce into non-toxic hemozoin crystals.