Toxins are poisonous substances that are produced by the cells of living organisms. Human toxins, therefore, refer to poisonous substances from living cells that are deadly to humans. Naturally, toxins are produced by living organisms for functions in their bodies and cells. The two primary functions of toxins are predation and defence. Spiders, jellyfish, wasps, and sea anemones use their toxins to kill for food. On the other hand, bees, some plants, and ants use their toxins as a defense means to avoid predation. The effects of toxins on humans can range from mild to severe depending on the composition and source. The severity of the effects of some toxins makes them targets for terrorists as biological weapons. Due to their differences toxins are grouped based on various attributes. In the first system, toxins can be classified based on whether they are from plants, algae, or bacteria (CDC, 2017). In the second system, they can be classified as either endotoxins or exotoxins. Exotoxins are those excreted by the living organism, while endotoxins are naturally part of the living cell’s structure. This research discusses toxins, their classification, functions in their hosts, effects on humans, and antidotes.
Classification
Toxins can be classified as exotoxins or endotoxins and by their source organism. Exotoxins are secreted by specific bacteria and diffuse into their surroundings. In most instances, the chemical structure of these exotoxins can be easily altered through changes in the environments like heat and pH. On the other hand, exotoxins are lipopolysaccharide-protein structural complexes found on the surface of Gram-Negative bacteria. While exotoxins are released regularly during the normal cell excretion process, endotoxins are released when the bacteria die or during self-destruction. Due to the differences in the nature and structure of both sets of toxins, exotoxins are seen as highly toxic even in small quantities compared to endotoxins. Examples of bacteria-produced exotoxins and endotoxins are bufotoxin and botulinum respectively.
In another category, toxins can be classified based on sources such as bacteria, fungi and algae, and plants. Anthrax lethal toxin is an endotoxin produced by Bacillus anthracis. This toxin affects humans by disrupting the function of the immune system. Botulinum toxin is one of the most poisonous substances produced from living cells. The toxin is produced by Clostridium botulinum and it causes a condition that paralyzes the muscles known as botulism. Pertussis is a toxin produced by Bordetella pertussis, known for causing whooping cough. Staphylococcal enterotoxin B is a toxin that causes most food poisoning cases (CDC, 2017). These toxins have been known for a long time to cause human infections.
Fungi and algae are associated with aflatoxins, saxitoxins, and amanitin, while plants produce abrin and ricin. Aflatoxins originate from a fungus called Aspergillus and are found as a contaminant in corn during harvesting, storage, and processing. Excess and prolonged exposure to aflatoxins is associated with chronic and acute injuries to the liver leading to liver cancer. Even due to these effects aflatoxin contamination is unavoidable especially for consumers of corn and peanuts. The level of aflatoxin contamination is regulated by the Food and Drug Administration (FDA). Their effects on humans are similar to amanitin, which is produced by the death cap mushroom. Intake of this toxin leads to failure of the kidney and liver and sometimes, death. Another algae-based toxin is saxitoxin which is produced by cyanobacteria, which include fresh water and blue-green algae. High concentrations of saxitoxin in sea fish such as oysters and clams may cause paralytic poisoning, which if left untreated may cause death.
Effect on Humans
Overall, the toxins from bacteria, fungi, algae, and plants are implicated in various common diseases and conditions. Some of these toxins have been categorized as the most deadly to humans, including botulinum, tetanus, diphtheria, muscarine, and bufotoxin. The body organs and tissues affected by these toxins can also be used to categorize them. Hemotoxins can damage blood cells and result in general damage to tissues. Phototoxins can cause allergic reactions in individuals susceptible to certain toxins. Necrotoxins are produced by spiders and cause general tissue damage and destroy cells within the area of infection. Neurotoxins are toxins that affect the nervous system impairing part of the human senses.
Antidotes
Antidotes are substances made from toxins and are designed to cure the effects of specific toxins. The mechanism of antidotes is that small amounts of the toxins are introduced into the human system to trigger immune reactions and produce antibodies against the toxin molecules. When designing the antidote, serum containing the antibodies of the toxin host is used to trigger immune reactions. While not all toxins have antidotes, they can be used to design substances that calm their poisoning effects. The CDC is currently committed to techniques that can be used to detect, diagnose, treat and prevent infections from toxins. More samples are also being analyzed to help in categorizing various forms of toxins to make it easier to detect and cure their effects.
Reference
Centers for Disease Control and Prevention. (2017). Toxins. Web.