It is hygroscopic and thus often encountered as a colorless viscous hydrated syrup that smells of trimethylamine (TMA). Aqueous solutions of choline are stable, but the compound slowly breaks down to ethylene glycol, polyethylene glycols, and TMA.Choline chloride can be made by treating TMA with 2-chloroethanol:
(CH3)3N + ClCH2CH2OH → (CH3)3N+CH2CH2OH · Cl–The 2-chloroethanol can be generated from ethylene oxide. Choline has historically been produced from natural sources, such as via hydrolysis of lecithin. Metabolism
Biosynthesis
In plants, the first step in de novo biosynthesis of choline is the decarboxylation of serine into ethanolamine, which is catalyzed by a serine decarboxylase. The synthesis of choline from ethanolamine may take place in three parallel pathways, where three consecutive N-methylation steps catalyzed by a methyl transferase are carried out on either the free-base, phospho-bases, or phosphatidyl-bases. The source of the methyl group is S-adenosyl-L-methionine and S-adenosyl-L-homocysteine is generated as a side product. In humans and most other animals, de novo synthesis of choline is via the phosphatidylethanolamine N-methyltransferase (PEMT) pathway, but biosynthesis is not enough to meet human requirements. In the hepatic PEMT route, 3-phosphoglycerate (3PG) receives 2 acyl groups from acyl-CoA forming a phosphatidic acid. It reacts with cytidine triphosphate to form cytidine diphosphate-diacylglycerol. Its hydroxyl group reacts with serine to form phosphatidylserine which decarboxylates to ethanolamine and phosphatidylethanolamine (PE) forms. A PEMT enzyme moves three methyl groups from three S-adenosyl methionines (SAM) donors to the ethanolamine group of the phosphatidylethanolamine to form choline in the form of a phosphatidylcholine.
Ebola, also known as Ebola virus disease (EVD) and Ebola hemorrhagic fever (EHF), is a viral hemorrhagic fever in humans and other primates, caused by ebolaviruses. Symptoms typically start anywhere between two days and three weeks after becoming infected with the virus. The first symptoms are usually fever, sore throat, muscle pain, and headaches. These are usually followed by vomiting, diarrhoea, rash and decreased liver and kidney function, at which point, some people begin to bleed both internally and externally. The disease kills between 25% and 90% of those infected – about 50% on average. Death is often due to shock from fluid loss, and typically occurs between six and 16 days after the first symptoms appear.The virus spreads through direct contact with body fluids, such as blood from infected humans or other animals, or from contact with items that have recently been contaminated with infected body fluids. There have been no documented cases, either in nature or under laboratory conditions, of the disease spreading through the air between humans or other primates. After a person recovers from Ebola, their semen or breast milk may continue to carry the virus for anywhere between several weeks to several months. Fruit bats are believed to be the normal carrier in nature; they are able to spread the virus without being affected by it. The symptoms of Ebola may resemble those of several other diseases, including malaria, cholera, typhoid fever, meningitis and other viral hemorrhagic fevers.