Xylose isomerase (XI) catalyzes the isomerization and epimerization of hexoses, pentoses and tetroses. In order to clarify the reasons for the low reaction efficiency of a pentose sugar, L-arabinose, we determined the crystal structure of Streptomyces rubiginosus XI complexed with L-arabinose. The crystal structure revealed that, when compared with D-xylose and D-glucose, L-arabinose binds to t...

Flying vertebrates have been hypothesized to have a high capacity for paracellular absorption of nutrients. This could be due to high permeability of the intestines to nutrient-sized molecules (i.e., in the size range of amino acids and glucose, MW 75-180 Da). We performed intestinal luminal perfusions of an insectivorous bat, Tadarida brasiliensis. Using radio-labeled molecules, we measured th...

BACKGROUND Microbial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50% of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates. METHODS R. toruloides was grown in batch and fed-batch cultures in...

This article evaluates the effect of membrane active channel-forming polyene antibiotic (PA) of levorin and its alkyl derivatives on the muscle performance. The membrane channels of muscle cells are capable to transport ions of potassium, sodium, and calcium. In the period of an intensive muscle exercise, the necessity for organic substrates increases and these channels start to work with the g...

The biocatalytic reduction of D-xylose to xylitol requires separation of the substrate from L-arabinose, another major component of hemicellulosic hydrolysate. This step is necessitated by the innate promiscuity of xylose reductases, which can efficiently reduce L-arabinose to L-arabinitol, an unwanted byproduct. Unfortunately,due to the epimeric nature of D-xylose and L-arabinose, separation c...

A major benefit of supplementing non-ruminant feedstuffs with exogenous enzymes is presumed to be the degradation of plant cell-wall polysaccharides to metabolizable monosaccharide residues. In the present study, metabolic fates of (U-14C-labelled, 10 mM) glucose, galactose, mannose, xylose and arabinose were compared in the fowl, by measuring recoveries of 14C radioactivity in exhaled carbon d...

1. Steers, fitted with simple rumen and duodenal cannulas, were given diets of approximately equal parts of flaked maize and hay (A) (containing 16 g nitrogen/kg dry matter (DM) or diets of flaked maize and straw supplemented with decorticated groundnut meal (B), fish meal (C), or heated (D) or unheated (E) soya-bean meal (containing 24 g N/kg DM). Chromic oxide was given as a marker with the f...

Dobrogosz, Walter J. (University of Illinois, Urbana) and Ralph D. DeMoss. Induction and repression of l-arabinose isomerase in Pediococcus pentosaceus. J. Bacteriol. 85:1350-1355. 1963.-The inducible l-arabinose isomerase of Pediococcus pentosaceus can be rapidly and conveniently measured in whole-cell preparations by use of a standard colorimetric procedure originally developed for studies wi...

Water-soluble nutrients are absorbed by the small intestine via transcellular and paracellular mechanisms. Based on a few previous studies, the capacity for paracellular nutrient absorption seems greater in flying mammals than in nonflying mammals, but there has been little investigation of the mechanisms driving this difference. Therefore, we studied three species each of bats (Artibeus litura...

Englesberg, E. (University of Pittsburgh, Pittsburgh, Pa.), R L. Anderson, R. Weinberg, N. Lee, P. Hoffee, G. Huttenhauer, and H. Boyer. l-Arabinose-sensitive, l-ribulose 5-phosphate 4-epimerase-deficient mutants of Escherichia coli. J. Bacteriol. 84:137-146. 1962-l-Arabinose-negative mutants of Escherichia coli B/r, ara-53 and ara-139, are deficient in the enzyme l-ribulose 5-phosphate 4-epime...