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Biomedical subjects

A Jobson

Publications and source records attributed to A Jobson.

5 recordsLinked to original sources
PubMed1976

Microbial utilization of raw and hydrogenated shale oils.

The biodegradability of raw and hydrogenated shale oils prepared by a retort process were studied under psychrophilic and mesophilic conditions. Changes in bacterial numbers and the chemical composition of the oils were monitored using a plate count and chromatographic techniques respectively. Raw shale oil was found to be relatively resistant to microbial attack whereas hydrogenated shale oil was readily utilized for microbial growth. Populations enriched on raw shale oil had a reduced ability to use hydrogenated shale oil under similar conditions. Gram-negative rods predominated in all enrichment populations. It is recommended that to facilitate clean up of shale oil spills, raw shale oil be reduced at the extraction site before transport.

Alcaligenes↗
PubMed1976

Bouyant density, conversion formulae, and the mole percent guanosine + cytosine content of Desulfovibrio sp.

A reevaluation of the original buoyant density conversion formula used to calculate the molar percentage guanosine + cytosine (% G + C) contents of the accepted species of genus Desulfovibrio has been undertaken. It would appear that the formula used gives values 4-5% lower than those obtained using formulae more generally cited in modern literature. Recalculations of % G + C content values for Lesulfovibrio DNA are presented using the formulae of three different workers, and are compared with those values originally used in the classification of genus Desulfovibrio.

Centrifugation, Density Gradient↗
PubMed1974

Effect of amendments on the microbial utilization of oil applied to soil.

Replicate field plots comprising a control, plus oil, plus oil and bacteria, plus oil and fertilizer (urea-phosphate; 27:27:0), and plus oil, bacteria, and fertilizer were monitored over a 308-day period for changes in bacterial and mold numbers. Changes in the chemical composition of the oil applied to the plots was followed by using chromatographic techniques. Application of fertilizer resulted in a stimulation of bacterial numbers and in the rate of utilization of n-alkane components of the saturate fraction. The application of oil-utilizing bacteria, however, resulted in only a slightly accelerated rate of utilization of n-alkane components of chain lengths C20 to C25. The isoprenoids, phytane and pristane, were still present in gas-liquid chromatography profiles after digestion of the n-alkane components of the saturate fraction. Those plots which received fertilizer showed an accelerated rate of recovery of native vegetation.

Alcaligenes↗
PubMed1972

Microbial utilization of crude oil.

The utilization of two crude oil samples of different quality at 4 and 30 C has been studied by using pure and mixed bacterial cultures obtained by enrichment procedures. Growth, emulsification, and utilization occurred readily at both temperatures. The crude oil residue is increased in specific gravity and readily sediments out of solution. A comparison of the chemical analysis of the oils by liquid and gas-liquid chromatographic procedures before and after growth showed that the n-saturate fraction had been preferentially used. Some utilization of the aromatic fraction also occurred. Enrichments obtained with a high-quality crude oil were not as effective in utilizing a lower quality crude oil as sole carbon source as a population enriched on the low-quality crude oil.

Alcaligenes↗