Environment Folic acid

The Falin-Ciocalteu reagent (FCR) is a complex formed in a reaction between sodium tungstate and sodium molybdenate in hydrochloric add and phosphoric acid, which turns yellow after lithium sulphate is added. The reagent reads in an alkaline environment with reducing compounds. Such a reaction gives a blue chromophore which is observed by colorimetry. The Folin-Ciocalteu method is highly sensitive - both to phenolic and non-phenolic compounds, e.g. proteins, vitamin C, vitamin Bj, folic acid, Cu(I). The method is applied most frequently to determine the total content of phenolic compounds [34,35]. If that is the case, a sample for determination should be prepared in a proper manner to minimise the effect of non-phenolic... 

Soybean meal is generally low in minerals and vitamins (except choline and folic acid). About two-thirds of the P in soybeans is bound as phytate and is mostly unavailable to animals. This compound also chelates mineral elements including Ca, magnesium, potassium, iron and zinc, rendering them unavailable to poultry. Therefore, it is important that diets based on soybean meal contain adequate amounts of these trace minerals. Another approach to the phytate problem is to add phytase, a phytic acid degrading enzyme, to the feed to release phytin-bound P. A benefit of this approach is that less P needs to be added to the diet, reducing excess P loading into the environment. 

Even when the pharmacokinetic parameters of a drug are such to suggest that it will reach the site of the infection, local factors can influence its antimicrobial activity. Aminoglycosides are ineffective in hyperosmolar, anaerobic acidic environments, such as the purulent environment of abscesses. Sulfonamides act by replacing para-aminobenzoic acid (PABA) in the folic acid synthetic pathway of bacteria and are ineffective in purulent material and necrotic tissue, which provide alternative sources of PABA. 

Folic acid is a vitamin required for the transfer of methyl groups in the biosynthesis of methionine and nitrogenous bases. Humans cannot synthesize folic acid and must obtain it from the diet. Bacteria, on the other hand, must make folic acid because they cannot take it in from the environment. 

By the thymineless death method a situation is created in which the parental cells die and the mutant cells do not grow but are able to stay alive in the selective environment. Since mammalian cells utilize thymidine instead of thymine, a state of thymidine starvation is created by exposing cells to a folic acid antagonist, such as aminopterin. Under these conditions, the prototrophs continue to grow until death, while the auxotrophs do not grow but remain alive and can thus be rescued. This method has been successfully applied to isolation of glutamine-requiring mutant lines from HeLa cells (De Mars and Hooper, 1960) and Chinese hamster cells (Chu et aLy 196%). 

Nutrigenetics Nutrigenetics interested in the influence of genetic variation between individuals on metabolic or physiological responses induced by nutrient intake, in this case, folic acid. It helps to understand the cause of the variability of responses from one individual to the other side to a given environment such as folate metabolism. 

Pyrimethamine is usually given in combination with sulfadoxine (Fig. 25.5) which, like many sulphonamide antibacterial compounds, is an inhibitor of the biosynthesis of dihydropteroate which is a precursor of folic acid. Unlike humans, plasmodia synthesise folic acid rather than absorb it from the environment. It is used for prophylaxis rather than treatment. 

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