Delbert E. Philpott

Light meromyosin fraction I: A helical molecule from myosin

The fractionation of light meromyosin (LMM), obtained from myosin after short trypsin digestion, is described. About 50% of the total LMM is not denatured by ethanol. This portion, termed light meromyosin Fraction I (LMM Fr: 1), has a molecular weight of 120,000, behaves as a homogeneous material in hydrodynamic studies, and appears to be a single component on diethylaminoethyl-substituted cellulose columns. Optical rotation studies are compatible with the interpretation that this component of myosin is a fully coiled α-helix in solution. LMM Fr. 1 is further characterized by a 430 A period in low-angle X-ray and electron microscope studies. The structure of the molecule and its relationship to myosin are discussed.

THE NATURE and SIGNIFICANCE OF INVERTEBRATE CARTILAGES

Invertebrate endoskeletal cartilage and cartilage-like tissues occurrence and nature, discussing cellular tissues and origin

The structure of light-meromyosin: an electron microscopic study.

Abstract Light-meromyosin crystals show a principal periodicity of 420 ± 25 A along the main axis with an additional structure in the electron microscope. This periodicity agrees with the value of the fundamental fiber period found in muscle by X-ray crystallography by Bear and by Huxley .

The fine structure of the flagellar apparatus of Chlamydomonas moewusii

Abstract The flagella of Chlamydomonas moewusii are similar to those of other Protista except for a small cylinder which lies within the peripheral fibrils in the basal region of the flagellum and is traversed by a diaphragm. The flagella of the 11 nonmotile mutants examined display no abnormality in internal structure, though in some strains the flagella are only 0.6–1.0 μ in length. The protoplasmic bridge joining mated cells has an electron-dense core formed by extensions from the anterior projections of the blepharoplasts.

The series elastic component in muscle

Abstract Electron microscopic pictures of the muscle show that the protofibrils of the cross striated muscle are built alternatingly of contractile and elastic segments. The division lies in histological dimensions. In its middle every sarcomer contains such an elastic segment.

Observations on the electron microscopic structure of insect muscle.

Abstract Four electron micrographs are reproduced. The longitudinal section of the wing muscle of the house-fly shows the absence of the series elastic component and of the A and I bands. The possible bearing on the genesis of these bands is discussed. Mitochondria of the wing muscle of the bumble-bee show a tubular inner structure, while the mitochondria of the leg muscle show laminar formations.