Rate of digestion of foods and postprandial glycaemia in normal and diabetic subjects.

Carbohydrate portions (2 g) of lentils, soya beans, and wholemeal bread were incubated for three hours with human digestive juices and the effect of digestibility on blood glucose examined. Lentils and soya beans released only 39% and 8% respectively of the sugars and oligosaccharides liberated from bread. In healthy volunteers 50 g carbohydrate portions of cooked lentils and soya beans raised blood glucose concentrations by only 42% (p < 0.001) and 14% (p < 0.001) of the bread value. There was a similar response in diabetics. These results suggest that rate of digestion might be a important factor determining the rise in blood glucose concentration after a meal and that supplementing chemical analysis with in-vitro and in-vivo food testing might permit identification of especially useful foods for diabetics.     

The genetic architecture of fitness in a seed beetle: assessing the potential for indirect genetic benefits of female choice

Background  

Quantifying the amount of standing genetic variation in fitness represents an empirical challenge. Unfortunately, the shortage of detailed studies of the genetic architecture of fitness has hampered progress in several domains of evolutionary biology. One such area is the study of sexual selection. In particular, the evolution of adaptive female choice by indirect genetic benefits relies on the presence of genetic variation for fitness. Female choice by genetic benefits fall broadly into good genes (additive) models and compatibility (non-additive) models where the strength of selection is dictated by the genetic architecture of fitness. To characterize the genetic architecture of fitness, we employed a quantitative genetic design (the diallel cross) in a population of the seed beetle Callosobruchus maculatus, which is known to exhibit post-copulatory female choice. From reciprocal crosses of inbred lines, we assayed egg production, egg-to-adult survival, and lifetime offspring production of the outbred F1 daughters (F1 productivity).     

Structurally colored thiol chitosan thin films as a platform for aqueous heavy metal ion detection

Thin films of the polysaccharide chitosan and several chitosan derivatives, including conjugates of l-cysteine, thioglycolic acid, and 2-iminothiolane, were produced from dilute acidic solutions. Attempts to produce a fourth conjugate using lipoic acid resulted in the synthesis of partially N-acetylated chitosan ethanoate. These biopolymer films were exposed to solutions containing 50 ppm concentrations of various metal ion and counterion analytes. Analyte-induced changes in film thicknesses and refractive indices were measured using a spectroscopic ellipsometer, and shifts in film color were quantified using a reflectance spectrometer. The modified chitosans were generally more sensitive to change in response to pure water but also showed varied response to several ions of interest, including Cr(III) and Cr(VI), Hg(II), Ni(II), and others. The potential for tuning film response was demonstrated by varying the concentration of sulfur groups in the thioglycolic acid conjugate, leading to increased specificity for Hg(II).     

Multiple, non-allelic, intein-coding sequences in eukaryotic RNA polymerase genes

Background  

Inteins are self-splicing protein elements. They are translated as inserts within host proteins that excise themselves and ligate the flanking portions of the host protein (exteins) with a peptide bond. They are encoded as in-frame insertions within the genes for the host proteins. Inteins are found in all three domains of life and in viruses, but have a very sporadic distribution. Only a small number of intein coding sequences have been identified in eukaryotic nuclear genes, and all of these are from ascomycete or basidiomycete fungi.