Acute and chronic effects of dietary fatty acids on cholecystokinin expression, storage and secretion in enteroendocrine STC-1 cells

Cholecystokinin (CCK) is a peptide hormone secreted from the I-cells of the intestine and it has important physiological actions related to appetite regulation and satiety. In this study we used STC-1 cells to investigate the effects of common dietary-derived fatty acids (FAs) on I-cell secretory function and metabolism. We extend earlier studies by measuring the acute and chronic effects of 11 FAs on CCK secretion, cellular CCK content, CCK mRNA levels, cellular DNA synthesis, cellular viability and cytotoxicity. FAs were selected in order to assess the importance of chain length, degree of saturation, and double bond position and conformation. The results demonstrate that secretory responses elicited by dietary FAs are highly selective. For example, altering the conformation of a double bond from cis to trans (i.e. oleic acid versus elaidic acid) completely abolishes CCK secretion. Lauric acid appears to adversely affect I-cell metabolism and arachidonic acid suppresses DNA synthesis. Our studies reveal for the first time that conjugated linoleic acid isoforms are particularly potent CCK secretagogues, which also boost intracellular stores of CCK. These actions of conjugated linoleic acid may explain satiating actions observed in dietary intervention studies.

Energy levels and radiative rates for transitions in B-like to F-like Xe ions (Xe L-XLVI)

Energy levels, radiative rates, oscillator strengths, line strengths, and lifetimes have been calculated for transitions in B-like to F-like Xe ions, Xe L–XLVI. For the calculations, a fully relativistic grasp code has been adopted, and results are reported for all electric dipole, electric quadrupole, magnetic dipole, and magnetic quadrupole transitions among the lowest 125, 236, 272, 226, and 113 levels of Xe L, Xe XLIX, Xe XLVIII, Xe XLVII, and Xe XLVI, respectively, belonging to the n ⩽ 3 configurations.

The effect of slurry storage and anaerobic-digestion on survival of pathogenic bacteria

The decline in viable numbers of Salmonella typhimurium, Yersinia enterocolitica and Listeria monocytogenes in beef cattle slurry is temperature-dependent; they decline more rapidly at 17-degrees-C than at 4-degrees-C. Mesophilic anaerobic digestion caused an initial rapid decline in the viable numbers of Escherichia coli, Salm. typhimurium, Y. enterocolitica and L. monocytogenes. This was followed by a period in which the viable numbers were not reduced by 90%. The T90 values of E. coli, Salm. typhimurium and Y. enterocolitica ranged from 0.7 to 0.9 d during batch digestion and 1.1 to 2-5 d during semi-continuous digestion. Listeria monocytogenes had a significantly higher mean T90 value during semi-continuous digestion (35.7 d) than batch digestion (12.3 d). Anaerobic digestion had little effect in reducing the viable numbers of Campylobacter jejuni.

The role of higher-order chromatin structure in the yield and distribution of DNA double-strand breaks in cells irradiated with X-rays or alpha-particles

Purpose: To determine whether the non-random distributions of DNA double-strand breaks in cells observed after alpha-particle irradiation are related to the higher-order structure of the chromatin within the nucleus.