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Biomedical subjects

G B Patel

Publications and source records attributed to G B Patel.

47 records · Page 3Linked to original sources
PubMed1981

A simple apparatus for measuring the Eh of anaerobic media.

A 22-mm outside diameter screw cap test tube was modified for measuring the redox potential (Eh) of samples of anaerobic media. The screw cap was fitted with a grey butyl rubber septum with a hole through which a platinum-calomel combination electrode was inserted. The tube was shortened in length and a small side arm that could be sealed with a serum stopper and an aluminium seal was attached. This device enabled the measurement of Eh of anaerobic media without the need for continuous flushing of the vessel headspace to maintain anaerobiosis.

Anaerobiosis↗
PubMed1980

Composition of Methanospirillum hungatii GP1 during growth on different media.

Growth of Methanospirillum hungatii GP1 as determined by optical density measurement wsa comparable to growth assessed by cell dry weight, ribonucleic acid content, and deoxyribonucleic acid content. Cultivation of M. hungatii on synthetic medium containing mineral salts, vitamins, and acetic acid indicated that, on a dry weight basis, cell constituents such as protein (71%), ribonucleic acid (15.8%), deoxyribonucleic acid (1.6%), and total carbohydrate (3.2%) did not vary significantly with the growth phase. Cells grown in the synthetic medium supplemented with yeast extract and tryptone had slightly higher protein content (76%), but the concentrations of the other cell constituents were similar and did not fluctuate much during growth. Nitrogen limiting growth resulted in somewhat lower ribonucleic acid content as well as slightly higher protein content than that in cells grown in nonlimiting medium. Methanospirillum hungatii did not accumulate any of the commonly known reserve materials under nitrogen or carbon and hydrogen limiting growth.

Acetates↗
PubMed1980

Viability and depletion of cell constituents of Methanospirillum hungatii GP1 during starvation.

The viability of Methanospirillum hungatii GP1 cells dropped rapidly when starved in a pH 7.0 phosphate buffer under 100% N2 or 90% N2 - 10% H2 gas phase. The presence of H2 during starvation tests resulted in a more rapid and an ultimately greater reduction of the number of initially viable cells than in the presence of N2 only. The decrease in viability was observed concurrently with the decline of the ATP pool and the RNA content of the cells. The cell protein, carbohydrate, and amino acid pool also decreased. The cellular DNA content which increased initially under both gas phases subsequently decreased under N2-H2 gas phase. However, there was no net decline in the DNA content of the cells. The results indicate that M. hungatii would not survive prolonged periods of starvation.

Adenosine Triphosphate↗
PubMed1978

Acetic acid and hydrogen metabolism during coculture of an acetic acid producing bacterium with methanogenic bacteria.

Two microorganisms originally existing as a mixed culture obtained from an anaerobic digester fluid were separated for pure and coculture studies. One of these was motile, Gram-negative, and non-sporeforming, and it required yeast extract for growth and acetic acid production. This isolate produced H2 and did not need H2 and (or) CO2 for growth and acetate formation. The other isolate was a methanogen whick resembled Methanobacterium arbophilicum in morphology and substrate specificity. Coculture growth of the two isolates in yeast extract broth (80% N2--20% CO2 gas phase) indicated that the non-methanogen produced up to four to five times more H2 than when grown separately. Although the growth of the non-methanogen was not enhanced by the removal of H2 by the methanogen, the hydrogen produced was essential for the growth of methanogen. Similar results were obtained when the non-methanogen was cocultured with Methanospirillum hungatti GP1. Cultivation of the non-methanogen in the presence of M. hungatti GP1 (under abundance of 80% H2--20% CO2) indicated that the acetate produced was consumed by M. hungatii, without inhibiting the growth of the other culture.

Acetates↗
PubMed1977

Effect of sodium chloride on growth and methane production of methanogens.

The effect of up to 263.7 mM sodium chloride on the growth and methane production by pure cultures of Methanospirillum hungatii GP1, Methanobacterium MOH, Methanobacterium thermoautotrophicum, and an unidentified methanogen was studied. Growth and methane production by M. hungatii GP1 were not affected up to 97.3 mM NaCl but there was some inhibition of growth at higher concentrations. Growth of Methanobacterium MOH was independent of sodium chloride concentration within the range investigated. For the unidentified methanogen, optimum growth and methane production occurred at 15.2 mM NaCl, while growth of M. thermoautotrophicum was not affected by sodium chloride concentrations up to 15.2 mM. Concentrations over 15.2 mM were inhibitory to these two organisms. The 15 mM sodium chloride concentration used by some investigators appears suitable for isolation and cultivation of methanogens since all the organisms tested in this study exhibited good growth and methane production at this salt concentration.

Anaerobiosis↗
PubMed1976

Factors affecting rate of methane formation from acetic acid by enriched methanogenic cultures.

A stable enrichment culture converting acetic acid to methane was successfully obtained from a pear waste digester, using a synthetic substrate solution with acetic acid as the main carbon source. This enrichment culture converted up to 10 mmol of acetic acid per litre per day at 35 degrees C and did not use hydrogen or formic acid in appreciable amounts as substrate for methane production instead of, or in addition to, acetic acid. The rate of conversion of acetic acid to methane was maximum at temperature of 40-45 degrees C, at a pH of 6.5 to 7.1, and was adversely affected by exposure to air, reducing agents, and high salt concentrations. The rate of conversion was independent of acetic acid concentration between 0.2 and 100 mM, but dropped markedly at concentrations below 0.2 mM.

Acetates↗
PubMed1976

Characterization of a strain of Methanospirillum hungatti.

The results of morphological, base ratio, nutritional, temperature, and pH studies on a strain of Methanospirillum hungatii, isolated from an anaerobic pear waste digester, are described. The isolate, designated as strain GP 1, was compared with some of the characteristics of type-strain M. hungatii JF 1. Strain GP 1 is Gram-negative, weakly motile, and a strict anaerobe with a guanine plus cytosine (G +C) content of 46.5 mol%. The preferred substrates for methane production are hydrogen, carbon dioxide, and formate. Acetate is used under certain conditions but its specific contribution to cell carbon and (or) methane formation was not established. The optimum temperature for both growth and methane production is 35 degrees C, but growth and methane production occur over the range 25-45 degrees C. Methane production is optimal at pH 7.0.

Acetates↗
PubMed1975

The relationship of acid-soluble glycogen to yeast flocculation.

A relationship between yeast flocculation and intracellular acid-soluble glycogen has been established which has been substantiated using flocculation mutants (mutants with altered capacities to flocculate) as well as a normal strain of Saccharomyces carlsbergensis. Sound evidence exists to implicate physiological differences in carbohydrate metabolism (glycogen storage) to this physical property of brewing significance.

Acids↗
PubMed1975

Glycogen--a physiological determinant of yeast flocculation?

Evidence is provided to extend earlier observations that glycogen and flocculence levels vary concurrently in brewing yeast. The use of glycogen mutants, the alterations of growth conditions specifically to inhibit glycogen storage, and observations on glycogen decreases during endogenous metabolism have verified the above. A mechanism by which glycogen might exert its effect on flocculation is suggested.

Acids↗
PubMed1973

Trends in wort carbohydrate utilization.

A gas chromatographic method suitable for any type of low-molecular-weight carbohydrate analysis has been utilized to determine the individual wort sugars in corn adjunct wort from a Western Canadian brewery. The fluctuations in each sugar during primary lager fermentation have been graphed. "End fermented" wort has been shown to contain some maltotriose, a small amount of maltose, and the nonfermentable carbohydrates, including maltotetraose, maltopentose, and dextrins.

Journal Article↗