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R E HUNGATE

Publications and source records attributed to R E HUNGATE.

At least 19 recordsLinked to original sources
PubMed1965

FERMENTATION CAPACITY AS A MEASURE OF NET GROWTH OF RUMEN MICROORGANISMS.

A simple technique for measuring the rate of fermentation of rumen microorganisms is described. It allows quick preparation and handling of the rumen sample immediately after collection. The average rate of fermentation of rumen samples collected from a lactating cow fed on alfalfa hay and concentrate in the ratio of 2:1 was very similar to the rate obtained by other methods. On the assumption that when substrate is in excess, the fermentation rate is proportional to the total microbial cells, the method was used to estimate the net growth of rumen microorganisms. The maximal fermentation rate of subsamples, taken at the beginning and after 1 hr of incubation of a sample, was measured. The results indicate a net average growth of 8% per hr, or 192% per day, in approximate agreement with rumen turnover time. The highest net growth does not necessarily coincide with the highest gas-production rate in the rumen, in part because the bicarbonate concentration in the rumen contents varies. In a cow fed on hay and concentrate, the net growth was lowest before feeding and immediately after feeding.

Animals↗
PubMed1964

VARIATION IN RUMEN BUTYRIVIBRIO STRAINS.

Margherita, S. S. (University of California, Davis), R. E. Hungate, and Hannelore Storz. Variation in rumen Butyrivibrio strains. J. Bacteriol. 87:1304-1308. 1964.-Five strains of Butyrivibrio isolated from the rumen of a single animal on an alfalfa hay ration were tested for serological relationships by agglutination and immunofluorescence. The main finding was a serological monospecificity of the strains. A cross-reaction between two strains was detected by agglutination and a second cross-reaction by immunofluorescence, but the cross-reacting pairs were different. Two years after the strains were isolated, fluorescein-conjugated antisera against three of them were used to test rumen contents of the same animal for homologous cell types. None was found. The findings indicate great variability in the serological characteristics of rumen butyrivibrios.

Animals↗
PubMed1963

Succinic acid turnover and propionate production in the bovine rumen.

High velocity constants for conversion of added succinate to propionate, together with estimations of pool size, showed that extracellular succinate is the major precursor of the propionate formed in the rumen. Some bacteria give off succinate as a final fermentation product which is decarboxylated by others to propionate.

Animals↗
PubMed1963

POLYSACCHARIDE STORAGE AND GROWTH EFFICIENCY IN RUMINOCOCCUS ALBUS.

Hungate, R. E. (University of California, Davis). Polysaccharide storage and growth efficiency in Ruminococcus albus. J. Bacteriol. 86:848-854. 1963.-Ruminococcus albus strain RAM requires biotin, p-aminobenzoic acid, pyridoxamine, isovalerate, isobutyrate, 2-methylbutyrate, and either cysteine or sulfide. Rumen fluid and casein hydrolysate improve growth but are not essential. Up to 35% iodophilic polysaccharide is stored in cells from batch cultures and 17% in a continuous culture on a 10-hr cycle. The storage product is a polymer of glucose resembling starch. The yield of cells in continuous culture, corrected for stored starch, averaged 102 mg per mmole of cellobiose fermented to waste products. It is postulated that nine high-energy phosphates are derived from each cellobiose molecule. Conversions providing this number are discussed.

4-Aminobenzoic Acid↗
PubMed1963

SEROLOGICAL ANALYSIS OF BUTYRIVIBRIO FROM THE BOVINE RUMEN.

Margherita, S. S. (University of California, Davis) and R. E. Hungate. Serological analysis of Butyrivibrio from the bovine rumen. J. Bacteriol. 86:855-860. 1963.-The cultural and fermentation characteristics of a number of strains of Butyrivibrio fibrisolvens isolated from the bovine rumen of cattle from different areas were determined, and the strains were subjected to serological analysis by the techniques of agglutination, immunodiffusion, and indirect hemolysis. In general, the results of the three methods agreed fairly well, but some variation was shown according to the method of preparation of the antigen. Much serological heterogeneity was disclosed. The greatest degree of agglutinating cross-reactivity was observed with strains isolated simultaneously from two animals in the same herd of African zebu cattle and with a Pullman strain. These cross-reactions were confirmed by immunodiffusion and indirect hemolysis tests. Agglutinating cross-reactions at low titers were observed between additional strains. The African isolates were shown to possess unique, as well as shared, antigens.

Agglutination Tests↗
PubMed1961

Rates of production of individual volatile fatty acids in the rumen of lactating cows.

The rumen fermentation rates in individual lactating cows were measured in four different experiments. The results disclosed that the amounts and proportions of volatile acids formed could vary widely. In one case, a marked difference in the proportions of the acids produced arose within the experiment and correlated with a difference in the proportion of methane formed. The average rate of production per day was 10.5 moles butyric acid, 12.8 moles propionic acid, and 40 moles acetic acid. Manometric estimations of rate gave lower results than those obtained by the zero-time method, due to delay after sampling and to failure of the acids to liberate stoichiometric quantities of carbon dioxide. For those experiments in which zero-time rates were estimated, the average specific absorption rates, i.e., the amount absorbed per hour per micromole of acid in the rumen, were 0.37 for butyric acid, 0.38 for propionic acid, and 0.26 for acetic acid. The carbon dioxide, acids, and microbial cells produced in the rumen fermentation are estimated to account for about 90% of the carbon found in the milk and respiratory CO(2) of the cows. The carbon dioxide from the fermentation was about 27% of the carbon dioxide exhaled.

Acetates↗
PubMed1959

Microbial fermentation in certain mammals.

The fermentation in the caecum and large intestine of ruminants is negligible compared with that in the rumen. In small ruminants the rate per unit contents is faster than in large ones, due to faster turnover. The cellulolytic bacteria of several ruminants are similar but differ in nutritional requirements.

Animals↗