Most of the chlorophylls and bacteriochlorophylls utilized for light harvesting by phototrophic organisms carry an ethyl group at the C8 position of the molecule, the product of a C8-vinyl reductase acting on a chlorophyll/bacteriochlorophyll biosynthetic precursor. Two unrelated classes of C8-vinyl reductase are known to exist, BciA and BciB, found in the purple phototroph Rhodobacter sphaeroi...

Fenoxycarb residues are analyzed by column switching and reversed-phase high performance liquid chromatography (RP-HPLC). The active ingredient is extracted from apples on a silica gel column using a n-hexane diethyl ether mixture. The eluate is evaporated, dry residue dissolved in acetonitrile-deionized water, and injected into the liquid chromatograph with a column switching system (C8 column...

A simple, specific and sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of rifampin in human plasma. Rifampin and sulindac (internal standard) are extracted from human plasma using a C2 Bond Elut extraction column. A 100-microliter volume of 0.1 M HCl is added to the plasma before extraction to increase the retention of the compounds on the ext...

A HPLC-UV/Vis method using a two-column strategy with a switching valve for on-line sample cleanup was developed for the determination of cyanocobalamin (CN–Cbl/Vitamin B12) in multivitamin dietary supplement tablets. The method uses two columns: an Agilent Zorbax C8 (150 mm 4.6 mm, 5 mm particle size) reversed-phase column and a Waters Symmetry C18 (150 mm 4.6 mm, 5 mm particle size) reversed-...

Subcritical water has been recently employed as the mobile phase to eliminate the use of organic solvents in reversed-phase liquid chromatography. Although the influence of temperature on retention in subcritical water chromatography has been reported, the temperature effect on peak width and column efficiency has not yet been quantitatively studied. In this work, several polar and chlorinated ...

A column-switching system with high-performance liquid-chromatographic separation and ultraviolet detection is described for automated determination of fluvoxamine in human plasma or serum. Samples were injected and the drug was retained in a clean-up column [20 x 4.6 mm (i.d.)] filled with C8 reversed-phase material (10-micron particles). After unwanted material was washed out, the drug was el...

In animal cells there are several regulatory complexes which interact with 20S proteasomes and give rise to functionally distinct proteasome complexes. γ -Interferon upregulates three immuno beta catalytic subunits of the 20S proteasome and the PA28 regulator, and decreases the level of 26S proteasomes. It also decreases the level of phosphorylation of two proteasome alpha subunits, C8 (α7) and...

Short-chain sphingolipids, such as C8-Glucosylceramide (C8-GC) have been described to enhance the cellular uptake of amphiphilic drugs, in free form or when coformulated in liposomes (1,2). The involved mechanism is currently unknown, but is hypothesized to induce domain or pore formation in the plasma membrane (3). The aim of this study is to further explore this specific drug uptake process b...

Chlorpyrifos is a pesticide that is metabolically activated to chlorpyrifos oxon (acetylcholinesterase inhibitor) primarily by the cytochrome P450 2B (CYP2B) enzyme subfamily in the liver and brain. We have previously shown that intracerebroventricular pretreatment with a CYP2B inhibitor, C8-Xanthate, can block chlorpyrifos toxicity. Here, we assessed whether delayed introduction of C8-Xanthate...

Focusing on the caprylic acid (C8:0), this study aimed at investigating the discrepancy between the formerly described beneficial effects of dietary medium chain fatty acids on body weight loss and the C8:0 newly reported effect on food intake via ghrelin octanoylation. During 6 weeks, Sprague-Dawley male rats were fed with three dietary C8:0 levels (0, 8 and 21% of fatty acids) in three experi...