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A Bacher

Publications and source records attributed to A Bacher.

236 records · Page 14Linked to original sources
PubMedDate not supplied

Nutritional requirement for 4-aminobenzoate caused by mutation of dihydropteroate synthetase.

Aerobacter aerogenes mutant 62-1 AC requires high concentrations of 4-aminobenzoate for growth. The mutant accumulates N-glucosyl-4-aminobenzoate and has an intact 4-aminobenzoate synthetase (Bacher, Gilch, Rappold, and Lingens, Z. Naturforsch. 28 c, 614-617 [1973]). On the other hand the ability of the mutant to synthesize dihydropteroate is markedly reduced. The dihydropteroate synthetase level of mutant 62-1 AC is 1% as compared to the parent strain. Spontaneous revertants of mutant 62-1 AC show wild type levels of dihydropteroate synthetase. We conclude that the requirement for 4-aminobenzoate in mutant 62-1 AC is due to poor utilization of 4-aminobenzoate as a consequence of the low level of dihydropteroate synthetase activity.

Aminobenzoates↗
PubMedDate not supplied

Tight junctions of jejunal surface and crypt cells in celiac disease: a freeze-fracture study.

We studied mucosal biopsies of five children with celiac disease and five controls of similar age by freeze-fracture electron microscopy. Morphometric parameters of membrane structure (such as apical tight junctions, triple tight junctions, intramembrane particles) and of the brush border were obtained from a large number of micrographs. The quantitative comparison of celiac patients and control subjects showed similar values for the depth of tight junctions at the level of the crypts. At the surface level, the tight junctions of celiac patients showed reduced depth as well as a reduced number of strands. The number of intramembrane particles of microvillus membranes increases in control subjects and in celiac patients as the cells migrate from the crypts to the mucosal surface. The specimens from celiac disease patients possessed a reduced density of intramembrane particles. Differences in brush border morphology between celiac patients and control subjects were similar to earlier findings.

Celiac Disease↗