Detection of ligand-protein binding by direct electrophoresis of the complex.
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Biomedical subjects
Publications and source records attributed to S Nobile.
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An Agrobacterium sp. isolated from soil is able to use gamma-butyrobetaine as its sole source of carbon and nitrogen. The involvement of thiol groups for active transport of gamma-butyrobetaine was investigated by use of the thiol alkylating reagent N-ethylmaleimide (NEM) and the dithiol specific reagent phenylarsine oxide (PAO). Both reagents strongly inhibited gamma-butyrobetaine uptake, but also induced the release of the accumulated substrate, suggesting that the transport system either contains a dithiol-dependent protein or that a small thiol-containing molecule is implicated in the uptake phenomenon.
A binding protein for gamma-butyrobetaine was purified from osmotic shock fluid of an Agrobacterium sp. It was a monomeric protein with an apparent molecular weight of 52,000 or 53,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, respectively. The isoelectric point was 4.3, as determined by isoelectric focusing. Amino acid analysis of the protein showed that Asx and Glx were predominant components and that the protein contained no cysteine. The dissociation constant of this protein for gamma-butyrobetaine was found to be 0.7 microM by equilibrium dialysis. Attempts to sequence the amino-terminal end with the Edman method failed, suggesting that this region of the protein is blocked.
An Agrobacterium sp. isolated from soil by selective growth on gamma-butyrobetaine (gamma-trimethylaminobutyrate) as the sole source of both carbon and nitrogen has been shown to possess an inducible transport system for this growth substrate. This transport system has a Kt of 0.5 microM and a maximal velocity of 3.8 nmol/min per mg (dry weight). The influx of gamma-butyrobetaine is optimal at pH 8.5 and operates against a concentration gradient. The transport system shows a high specificity for trimethylamine carboxylic acid molecules of defined chain length. gamma-Butyrobetaine uptake was significantly reduced in osmotically shocked cells and a gamma-butyrobetaine binding activity was detected in the crude shock fluid. This suggests a transport mechanism involving a periplasmic gamma-butyrobetaine binding protein.
Correction of proven vitamin deficiencies in patients with oral lichen planus resulted in both clinical and subjective improvement in the majority treated but did not produce complete remission of the lesions. The common finding of low levels of vitamins B1 and B6 in both the lichen planus group and in healthy controls suggests that this is a reflection of dietary habits of the local community not generally appreciated.
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The nutritional status of 66 part Aborginines was re-examined in 1974--with particular reference to blood levels of haemoglobin and vitamins--after white bread fortified with iron and the vitamins B1 and PP (niacin) had been available for six and half months to the population of Bourke, New South Wales. The results found in 1971 and 1974 are compared. A significant improvement from deficient to acceptable blood levels of vitamins B1 and B6 was found in 44% and 52% of the subjects respectively. This attributed to the comsumption of fortified bread since the levels of the other vitamins had remained either unchanged or worsened. The biochemical improvement in vitamin B6 is attributed to the sparing effect of vitamin PP on vitamin B6 requirement because the conversion of tryptophan to niacin is impaired in vitamin B6 deficiency. Iron deficiency anaemia in children had decreased by 50% but this could have been due to many other factors besides the iron which had been added to the bread. Clinically there was a marked decrease in angular stomatitis and skin xerosis which could be related to the biochemical improvement of the two B-vitamins and a decrease in active trachoma and suppurative otitis media probably due to intensive treatment received since 1971. The results of this study and the extent of biochemical vitamin B1 and B6 deficiency found in other groups, indicate that fortification of bread may be of benefit to the community as a whole.
Clinical evaluation and estimation of blood levels of vitamins A, E, C, B1, B2, B6 and of total carotenoids were carried out in 52 consecutive children admitted to the Royal Alexandra Hospital for Children in Sydney during the winter epidemic of diarrhoea. The children included 37 Europeans and 15 Aboriginals, who were previously apparently healthy. Of these, 19 Europeans and ten Abororigines were studied also after recovery. The anthropometric, clinical, microbiological and biochemical data for each child is presented. Vitamin treatment, duration of symptoms, severity of diarrhoea, stool microbiology and the role of secondary malabsorption as a main cause of the depressed plasma vitamin levels found is discussed.
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