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Biomedical subjects

A Kolb

Publications and source records attributed to A Kolb.

78 records · Page 5Linked to original sources

[A general method for the determination of the conformation of nucleotides bound to an enzyme site. Interaction between glycogen phsophorylase b and nucleoside-5'-monophosphates].

The conformation of 5' nucleotides in the active site of glycogen phosphorylase b has been deduced from T2 relaxation time of protons H1, H8 and H2. It is shown by deuterium substitution of the purine ring in position 8 that the orientation of the base is anti in the case of strong activators like adenosine 5'-monophosphate, and syn in that of weak activators like inosine 5'-monophosphate.

Adenosine Monophosphate↗

[Light microscopy studies on the olfactory epithelium of the deer].

To examine the olfactory epithelium of the roe by the light microscope, the respective nasal region was prepared on the spot right on shooting, stained with a solution of Trypan-Blue, fixed in "Susa" thereafter, and was finally embedded in paraffin by the usual process. Macroscopically already a luxuriant development both of the endo- and ectoturbinalia was to be observed, filling the entire olfactory region of the nasal cavity with numerous folds, convolutions and ramifications. For the purpose of microscopic examination sections from 6 to 10 mum in thickness were made. The border between regio respiratoria and regio olfactoria runs irregularly. Again and again there are patches bare of receptors respectively glandular ones even in the olfactory region. The thickness of the olfactory mucous membrane varies from 140 to 400 mum, the height of the epithelium from 35 to 90 mum. The olfactory area was determined to total approx. 90 cm2 by means of two methods. The distribution of olfactory cells within the epithelium is a very irregular one, their number ranging from 4 to 62 cells per 1000 mum2. Most commonly a density of 24 to 42 cells was encountered. Taking a mean density of 33/1000 mum2 and an overall olfactory area of 90 cm2, the total number of olfactory cells was calculated to run up to 297 million. Sections which turned out well display several olfactory cells entire with pericaryon, dendrite, neck and capitulum with rupturing points of cilia on the latter. Olfactory cells exhibit big dimensional differences. Among other factors their size depends on their relative position within the epithelium and on the density of occurrence. Olfactory cells lying but sporadically within the epithelium mostly possess broad dendrites measuring slightly less in diameter than the pericaryon does, whereas densely situated receptors mainly present thin dendrites and small capitula. Some cell-parts vary independently from each other, some, however, seem to stand in certain relationship to each other. The great differences between individual olfactory cells give rise to the assumption that several cell types or cells of different function respectively are concealed behind it.

Animals↗

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Academies and Institutes↗

Genetic studies on the promoter of malT, the gene that encodes the activator of the Escherichia coli maltose regulon.

We report the construction of a chromosomal malT-lacZ gene fusion that is expressed under the control of the malT promoter in Escherichia coli K12. The resulting hybrid protein is soluble and stable in crude cellular extracts, which allowed us to measure very low levels of malTp activity. In this note, we confirm and extend previous observations on the regulation of malTp. We show that the promoter is 40-times less active in the absence of cAMP receptor protein (CRP) than in its presence, that CRP works by binding to the site centred at position -70.5, and that all of the elements necessary and sufficient for the regulation by CRP are located downstream from position -122.

Bacterial Proteins↗