Inhibition of the fermentation of propionate to methane and carbon dioxide by hydrogen, acetate, and propionate was analyzed with a mesophilic propionate-acclimatized sludge that consisted of numerous flocs (size, 150 to 300 mum). The acclimatized sludge could convert propionate to methane and carbon dioxide stoichiometrically without accumulating hydrogen and acetate in a propionate-minimal me...

The uptake of propionate by the isolated perfused rat liver is not influenced by oleate or glucagon. However, glucagon does stimulate glucose production in the presence of 10 flwl propionate and increases the incorporation of isotope from [14C]propionate into glucose. These observations have been interpreted to indicate a sparing of the metabolism of propionate in the citric acid cycle by endog...

1. The production rate of propionate in the rumen and the entry rate of glucose into the body pool of glucose in sheep were measured by isotope-dilution methods. Propionate production rates were measured by using a continuous infusion of specifically labelled [(14)C]propionate. Glucose entry rates were estimated by using either a primed infusion or a continuous infusion of [U-(14)C]glucose. 2. ...

Physiological and regulatory mechanisms that allow the alkane-oxidizing bacterium Pseudomonas butanovora to consume C2 to C8 alkane substrates via butane monooxygenase (BMO) were examined. Striking differences were observed in response to even- versus odd-chain-length alkanes. Propionate, the downstream product of propane oxidation and of the oxidation of other odd-chain-length alkanes followin...

Binary mixtures of the protic ionic liquid ethylammonium nitrate (EAN) and acetonitrile (AN) were studied at 25 1C over the entire composition range by means of broadband dielectric spectroscopy covering 0.2 r n/GHz r 89. The dielectric spectra could be decomposed into two relaxation processes, both of which proved to be composite modes. For dilute solutions the higher-frequency Debye relaxatio...

A number of instances of inhibitory effects of propionic acid on metabolic reactions have been reported. Grafflin & Green (1948) found that the oxidation of acetate by washed rabbit-kidney particles ('cyclophorase') was inhibited by propionate, which itself was not oxidized. The oxygen uptake of sheep-rumen epithelial tissue was shown (Pennington, 1954) to be markedly depressed by propionate in...

The metabolism of propionate in adipose tissue and its effect on lipogenesis was investigated. Fasting induced changes in propionate metabolism of adipose tissue, drastically reducing higher fatty acid synthesis and increasing glyceride-glyerol formation from low concentrations of propionate (0.25 mM). Propionate also promoted lipogenesis from acetate-1-(14)C in tissues of fasted rats, while it...

Carbon 13 NMR, radiotracer and mass spectrometry studies were performed to confirm that propionate and methylmalonate are incorporated into long chain branched hydrocarbons as the methyl branch unit, to determine whether the branching methyl group was added initially or toward the end of the elongation process, to determine the precursor of methylmalonate, and to examine the metabolism of propi...

The uptake and metabolism of propionate in the isolated perfused caudal lobe of the liver and in isolated hepatocytes were examined following treatment of sheep with glucagon or saline. Glucagon or sterile saline was infused at 9.8 micrograms/min for 3 h into the jugular vein and then the caudal lobe of the liver was removed surgically under anaesthesia. The caudal lobe was used either to prepa...