Bacteroides ruminicola, pure or combined with Selenomonas ruminantium, and Lachnospira multiparus, pure or combined with Succinivibrio dextrinosolvens, were grown on a medium with pectin as energy source. There was a difference in fermentation products between the pure and combined cultures and efficiency of substrate utilization was better with the combined cultures.

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PubMedDate not supplied

The effects of glycoprotein modification on beta-adrenoreceptors binding ability in rat cardiac membranes.

The present study was designed to test the effects of neuraminidase and some proteolytic enzymes on the binding of 125I-HYP (hydroxybenzylpindolol) to beta-adrenoreceptors of rat cardiac membranes. The influence of some S-S and -SH active agents on the ligand binding used was also examined. The decrease in membrane sialic acid content did not alter the binding of ligand used. The degradation of membrane protein by proteases resulted in a time and enzyme type dependent decrease in the binding of 125I-HYP. It was found that the dithiotreitol pretreatment produced more profound decrease in ligand binding than reduced glutathione. Cysteine and mercaptoethanol were ineffective. The effect of dithiotreitol was dependent on the time of preincubation and on the agent concentration used. The decrease in ligand binding was also observed after the alkylation of -SH groups by iodoacetamide and N-ethylmaleimide.

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PubMedDate not supplied

Effects of thyroid hormones and reverse-triiodothyronine (rT3) pretreatment on beta-adrenoreceptors in the rat heart.

Effects of thyroxine (T4), triiodothyronine (T3) or reverse-triiodothyronine (rT3) in vivo pretreatment or the effect of hypothyroidism on properties of beta-adrenoreceptors in the rat heart were investigated. beta-adrenergic antagonist hydroxybenzylpindolol (HYP125I) was used to estimate the maximal binding capacity (MBC) and the affinity (KD) of beta-adrenoreceptors. Both T4 and T3 in dose and time dependent manner increased MBC value but only slightly and insignificantly affected affinity of the beta-adrenoreceptor. The effect of T3 on MBC was higher than that of an equal dose of T4, but the latter effect persisted longer than that of T3. Hypothyroidism decreased MBC value, but increased the affinity of beta-adrenoreceptors. Pretreatment of rats with rT3 produced changes in beta-adrenoreceptors similar to those seen in hypothyroid rats.

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