The xylene ring of riboflavin originates by dismutation of the precursor, 6,7-dimethyl-8-ribityllumazine. The formation of the latter compound requires a 4-carbon unit as the precursor of carbon atoms 6 alpha, 6, 7, and 7 alpha of the pyrazine ring. The formation of riboflavin from GTP and ribose phosphate by cell extract from Candida guilliermondii has been observed by Logvinenko et al. (Logvi...

The gas phase pyrolysis of trichlorfon was investigated by the on-line gas chromatography - mass spectrometry (GC-MS) pyrolysis and theoretical calculations. Two reaction channels were proposed in the pyrolytic reaction, by analyzing the detected pyrolytic products in the total ion chromatography, including 2,2,2-trichloroacetaldehyde, dimethyl phosphite, and dichlorvos. Theoretical calculation...

Equimolar reactions between ZntBu2 and diphenyl phosphate (dpphe-H) or dimethyl phosphate (dmphe-H) result in the formation of [tBuZn(O2P(OR')2)]-type compounds which crystallize as tetranuclear aggregates, [tBuZn(dpphe)]4 (14) or [tBuZn(dmphe)]4 (24), with the phosphate ligands spanning 4-coordinate Zn centers. The utility of ZnMe2 instead of ZntBu2 dramatically changes the reaction outcome an...

The current analysis was carried out to determine the chemical components in leaves of R. minima (L.) DC. GC-MS methanolic extract Minima indicated presence 19 compounds. prevailing compounds were 1Pentadecene (14.31), alpha. Bisabolol (10.39%), 1Heptadecene (9.78%), Cyclohexene,4 (1,5dimethyl1,4hexadienyl (7.06%), 3Hexadecene (Z) (8.10%), Caryophyllene (6.58%), Neophytadiene (5.16%), Humulene ...

We studied the incorporation of [1-13C]ribose and [1,3-13C2]glycerol into the riboflavin precursor 6,7-dimethyl-8-ribityllumazine, using a riboflavin-deficient mutant of Bacillus subtilis. The formation of the pyrazine ring requires the addition of a four-carbon moiety to a pyrimidine precursor. The results show that C-6 alpha, C-6, C-7, and C-7 alpha of 6,7-dimethyl-8-ribityllumazine were bios...

A series of sequential experiments were carried out to determine optimum diluents, cryoprotectants, equilibration time, and thawing temperature for frozen duck semen in order to set up the commercial semen cryopreservating techniques which could be applied to the conservation of genetic resources, breeding, and commercial production in domestic ducks. In experiment 1, the seven semen extenders ...

The objective was to determine whether detectable levels of OP metabolites influence the relationship between BMI and cardiometabolic health. This cross-sectional study was conducted using 2227 adults from the 1999-2008 NHANES datasets. Urinary concentrations of six dialkyl phosphate metabolites were dichotomized to above and below the detection limit. Weighted multiple regression analysis was ...

The effect of carboxylic acids on the permeation of chlorpromazine was investigated through a dimethyl polysiloxane nonpolar membrane. The permeability of the diffusate, at pH 5.8, increases considerably in the presence of carboxylic acids or phosphate, probably due to an ion-pair formation between the relative anions and chlorpromazine.

A detailed characterization of p-nitrophenyl phosphate as energy-donor substrate for the sarcoplasmic reticulum Ca(2+)-ATPase was undertaken in this study. The fact that p-nitrophenyl phosphate can be hydrolyzed in the presence or absence of Ca(2+) by the purified enzyme is consistent with the observed phenomenon of intramolecular uncoupling. Under the most favorable conditions, which include n...