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...

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 electronic spectra of cold benzylium (C6H5-CH2 (+)) and 1-phenylethyl (C6H5-CH-CH3 (+)) cations have been recorded via photofragment spectroscopy. Benzylium and 1-phenylethyl cations produced from electrosprayed benzylamine and phenylethylamine solutions, respectively, were stored in a cryogenically cooled quadrupole ion trap and photodissociated by an OPO laser, scanned in parts of the UV ...

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...

1. Interactions in the rates of consumption of acetate, propionate and butyrate in sheep liver mitochondria were examined in the presence and absence of l-malate and alpha-oxoglutarate. 2. Acetate was not consumed in absence of ancillary substrate but utilization of acetate (7.2nmol/min per mg of protein) occurred in the presence of alpha-oxoglutarate. This consumption was abolished by propiona...

Aerobic, glucose-limited chemostat of Saccharomyces cerevisiae CBS 8066 co-metabolized propionate when this compound was added to the reservoir medium. Co-metabolism of propionate led to an increase of the biomass and protein yields. Attempts to grow S. cerevisiae on propionate as a sole source of carbon and energy were not successful. Activities of propionyl-CoA synthetase in cell-free extract...

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...