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Biomedical subjects

F O SCHMITT

Publications and source records attributed to F O SCHMITT.

At least 19 recordsLinked to original sources
PubMed1963

Tropocollagen: significance of protease-induced alterations.

Interaction properties of tropocollagen are markedly altered by treatment with pepsin. This treatment liberates terminal or near-terminal covalently bonded peptides whose amino acid composition is strikingly different from the composition of the pepsin-resistant triple-helix body of the macromolecule. Pepsin also converts most of the beta-chains to alpha-chains. This fact indicates that the interchain link is also external to the body of the macromolecule and probably involves peptides. The role of these properties in bioregulative mechanisms is briefly discussed.

Amino Acids↗
PubMed1957

Some chemical and structural properties of paramyosin.

Paramyosin fibrils from the adductor muscles of Venus mercenaria are soluble above neutrality at relatively high ionic strength. From this viscous solution it is possible, by reduction in ionic strength, to reprecipitate acicular crystals of paramyosin. In the electron microscope these fibrils manifest a symmetrical band pattern similar to that previously described by Hodge but differing in some details. The axial periods observed under the conditions of the experiment varied between 1700 and 2000 A and a simple band pattern of one-fifth the main period was frequently observed. ATPase activity of the myosin type but of much lower intensity was demonstrated. Tryptic fission of the protein occurs but the characteristics differ from those of myosin.

Animals↗
PubMed1950

The fibrous structure of the nerve axon in relation to the localization of "neurotubules".

In squid, frog, rat, and human nerves examined in thin sections with the electron microscope the axon contains, in addition to certain other particulates, characteristic filaments. These filaments have diameters ranging from about 100 to 200 A and have indefinite length. They frequently have a nodose appearance due to the presence of discontinuities sometimes fairly regularly spaced along the filaments. This structure differs unmistakably from that of the dense-edged fibrils called "neurotubules" and it is clear that the latter are not axonic constituents. Though dense-edged fibrils can readily be demonstrated in fragmented formalin-fixed nerve preparations, they are seldom observed in thin sections. When such structures were seen in these experiments they were located in the connective tissue sheath. The present evidence offers no support for the view that "neurotubules" are structural entities of normal intact nerves.

Animals↗