Toxication , toxification or toxicity exaltation is the conversion of a chemical compound into a more toxic form in living organisms or in substrates such as soil or water . The conversion can be caused by enzymatic metabolism in the organisms, as well as by abiotic chemical reactions . While the parent drug is usually less active, both the parent drug and its metabolite can be chemically active and cause toxicity , leading to mutagenesis, teratogenesis, and carcinogenesis. Different classes of enzymes, such as P450 monooxygenases , epoxide hydrolase , or acetyltransferases can catalyze the process in the cell, mostly in the liver.
18-474: Cry1Ac protoxin is a crystal protein produced by the gram-positive bacterium , Bacillus thuringiensis (Bt) during sporulation . Cry1Ac is one of the delta endotoxins produced by this bacterium which act as insecticides . Because of this, the genes for these have been introduced into commercially important crops by genetic engineering (such as cotton and corn) in order to confer pest resistance on those plants. Transgenic Bt cotton initially expressed
36-478: A single Bt gene , which codes for Cry1Ac. Subsequently, Bt cotton has added other delta endotoxins. Products such as Bt cotton, Bt brinjal and genetically modified maize have received attention due to a number of issues, including genetically modified food controversies , and the Séralini affair . Cry1Ac is also a mucosal adjuvant (an immune-response enhancer) for humans. It has been used in research to develop
54-487: A vaccine against the amoeba Naegleria fowleri . This amoeba can invade and attack the human nervous system and brain, causing primary amoebic meningoencephalitis , which is nearly always fatal. This protein -related article is a stub . You can help Misplaced Pages by expanding it . Protoxin Parent non-toxic chemicals are generally referred to as protoxins . While toxication is generally undesirable, in certain cases it
72-501: Is a calcium salt of oxalic acid with the chemical formula CaC 2 O 4 or Ca(COO) 2 . It forms hydrates CaC 2 O 4 · n H 2 O , where n varies from 1 to 3. Anhydrous and all hydrated forms are colorless or white. The monohydrate CaC 2 O 4 ·H 2 O occurs naturally as the mineral whewellite , forming envelope-shaped crystals, known in plants as raphides . The two rarer hydrates are dihydrate CaC 2 O 4 ·2H 2 O , which occurs naturally as
90-596: Is a coordination polymer featuring planar oxalate anions linked to calcium, which also has water ligands . Calcium oxalate can produce sores and numbing on ingestion and may even be fatal. The monohydrate and dihydrate can be distinguished by the shape of the respective crystals. About 76% of kidney stones are partially or entirely of the calcium oxalate type. They form when urine is persistently saturated with calcium and oxalate. Between 1% and 15% of people globally are affected by kidney stones at some point. In 2015, they caused about 16,000 deaths worldwide. Some of
108-412: Is converted into the hepatotoxic metabolite NAPQI via the cytochrome P450 oxidase system, mainly by the subfamily CYP2E1. Hepatic reduced glutathione (GSH) will detoxify this formed NAPQI quickly if APAP is taken at a proper level. In the case of overdoses, the storage of GSH will not be enough for NAPQI detoxication, thereby resulting in acute liver injury. Oxidoreductases are enzymes that catalyze
126-486: Is required for the in vivo conversion of a prodrug to a metabolite with desired pharmacological or toxicological activity. Codeine is an example of a prodrug, metabolized in the body to the active compounds morphine and codeine-6-glucuronide . Phase I of drug metabolism are bioactivation pathways, which are catalyzed by CYP450 enzymes, produce toxic metabolites and thus have the potential to damage cells. The unusual level of activity CYP450 enzymes might lead to
144-405: The brewing of beer. If not removed in a cleaning process, beerstone will leave an unsanitary surface that can harbour microorganisms. Beerstone is composed of calcium and magnesium salts and various organic compounds left over from the brewing process; it promotes the growth of unwanted microorganisms that can adversely affect or even ruin the flavour of a batch of beer. Calcium oxalate crystals in
162-399: The changes in drug metabolism and convert drugs into their more toxic forms. Among Phase I CYP450 enzymes, the subfamilies CYP2D6 and CYP3A are responsible for hepatotoxicity during drug metabolism with a number of different drugs, including flucloxacillin , troleandomycin , and troglitazone . Hepatotoxicity indicates the drug's toxicity to liver. Paracetamol (acetaminophen, APAP)
180-408: The end product of the ethylene glycol mechanism, calcium oxalate , may cause malfunction in the kidney and lead to more severe consequences. Other examples of toxication by enzymatic metabolism include: Increases in toxicity can also be caused by abiotic chemical reactions. Non-living elements affect the abiotic chemical reactions. Anthropogenic trace compounds (ATCs) have potential toxicity to
198-495: The genus Philodendron contain enough calcium oxalate that consumption of parts of the plant can result in uncomfortable symptoms. Insoluble calcium oxalate crystals are found in plant stems, roots, and leaves and produced in idioblasts . Vanilla plants exude calcium oxalates upon harvest of the orchid seed pods and may cause contact dermatitis . Calcium oxalate, as ‘beerstone’ , is a brownish precipitate that tends to accumulate within vats, barrels, and other containers used in
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#1733105075681216-402: The level of it by boiling and cooking them. They are a constituent in 76% of human kidney stones . Calcium oxalate is also found in beerstone, a scale that forms on containers used in breweries . Many plants accumulate calcium oxalate as it has been reported in more than 1000 different genera of plants. The calcium oxalate accumulation is linked to the detoxification of calcium ( Ca ) in
234-452: The mineral weddellite , and trihydrate CaC 2 O 4 ·3H 2 O , which occurs naturally as the mineral caoxite , are also recognized. Some foods have high quantities of calcium oxalates and can produce sores and numbing on ingestion and may even be fatal. Cultural groups with diets that depend highly on fruits and vegetables high in calcium oxalate, such as those in Micronesia , reduce
252-438: The organisms in aquatic system. Arsenic contamination in drinking water can be chemically toxic. The uptake and metabolism of arsenic may result in damage to the body. When organic arsenic is converted into more toxic inorganic arsenic, it causes carcinogenesis, cytotoxicity (toxic to cells) and genotoxicity (causing mutations in genes). Calcium oxalate Calcium oxalate (in archaic terminology, oxalate of lime )
270-415: The oxalate in urine is produced by the body. Calcium and oxalate in the diet play a part but are not the only factors that affect the formation of calcium oxalate stones. Dietary oxalate is an organic ion found in many vegetables, fruits, and nuts. Calcium from bone may also play a role in kidney stone formation. In one study of modulators of calcium oxalate crystallization in urine, magnesium- alkali citrate
288-598: The plant. Upon decomposition, the calcium oxalate is oxidised by bacteria, fungi, or wildfire to produce the soil nutrient calcium carbonate . The poisonous plant dumb cane ( Dieffenbachia ) contains the substance and on ingestion can prevent speech and be suffocating. It is also found in sorrel , rhubarb (in large quantities in the leaves), cinnamon , turmeric and in species of Oxalis , Araceae , Arum italicum , taro , kiwifruit , tea leaves, agaves , Virginia creeper ( Parthenocissus quinquefolia ), and Alocasia and in spinach in varying amounts. Plants of
306-681: The reactions that involve the transfer of electrons. Methanol in itself is toxic due to its central nervous system depression properties, but it can be converted to formaldehyde by alcohol dehydrogenase and then converted to formic acid by aldehyde dehydrogenase, which are significantly more toxic. Formic acid and formaldehyde can cause severe acidosis , damage to the optic nerve , and other life-threatening complications. Ethylene glycol (common antifreeze) can be converted into toxic glycolic acid , glyoxylic acid and oxalic acid by aldehyde dehydrogenase, lactate dehydrogenase (LDH) and glycolate oxidase in mammalian organisms. The accumulation of
324-561: The urine are the most common constituent of human kidney stones , and calcium oxalate crystal formation is also one of the toxic effects of ethylene glycol poisoning . Calcium oxalate is a combination of calcium ions and the conjugate base of oxalic acid , the oxalate anion. Its aqueous solutions are slightly basic because of the basicity of the oxalate ion. The basicity of calcium oxalate is weaker than that of sodium oxalate , due to its lower solubility in water. Solid calcium oxalate hydrate has been characterized by X-ray crystallography . It
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