Absorption and translocation of foliar-applied iron

The absorption of (59)Fe(3+) by the leaves of various plant species was studied. Stomata were found to play a major role in foliar absorption when leaves were totally submerged in treatment solutions, and a correlation was found to exist between stomatal area and absorption. Day treated leaves absorbed much more than did night treated leaves. The use of a surfactant markedly increased absorption. Translocation from treated leaves was demonstrated and was found to vary with species.

Myofibrillar adenosine triphosphatase activity of human heart tissue in congestive failure: effects of ouabain and calcium

Ouabain had no effect on myofibrillar adenosine triphosphatase (ATPase) activity in normal, hypertrophic, and failing hearts with concentrations of calcium chloride varying from 0 to 5.0 mM. The quantitative effects of CaCl 2 on myofibrillar ATPase were the same in all groups studied.

At necropsy it was found that myofibrillar ATPase activity of heart tissue from patients with clinical and pathologic diagnoses of failure from left ventricular volume and pressure overload was significantly lower than that of normal controls. The ATPase activity in patients with failure due to right ventricular volume and pressure overload was not significantly lower than that in normal controls. There was no difference in myofibrillar ATPase activity between normal left and normal right and between failing left and failing right ventricles.

The difference demonstrated at necropsy between normal and failing hearts was not a function of age or of hypertrophy per se.

Myofibrillar ATPase activity of hypertrophic nonfailing surgical pulmonary infundibular tissue was the same as that of normal postmortem ventricles. The ATPase activity of failing surgical papillary muscle in a small number of experiments was in the range of that found in failing postmortem ventricles.

An electron microscope study of canine cardiac myosin and some of its aggregates

The morphology of the canine cardiac myosin molecule has been investigated in the electron microscope with Hall's mica-replica technique. The molecule is an elongated rod (shaft) of nonuniform diameter with a globular expansion (head) on one end. Statistical analysis of the lengths of 1908 molecules showed that the mean length was 1610 +/- 250 A; the mean length of the head was 210 +/- 20 A; and the diameter of the head and that of the shaft were 35 to 40 and 15 to 20 A, respectively. About one-third of the molecules had single or multiple, fairly sharp, angulations along their shafts. Rarely, some details of the substructure of the molecule have been observed. Large, spindle-shaped aggregates, measuring 0.5 to 1 micro in length and 50 to 100 A in diameter, were produced by dilution of the myosin solutions. These aggregates were readily visualized in the electron microscope by means of Huxley's negative-staining technique. Projections often were visible along the length of the aggregates except at a central zone where they were frequently absent. The aggregates resembled the thick myofilaments of the myocardium and appeared similar to those produced by Huxley from skeletal myosin solutions.

Human cardiac myosin: electron microscopic observations

Solutions of human cardiac myosin contain macromolecules which were visualized in the electron microscope by the shadow-casting technic. The dominant particle was observed to be rod-shaped, to have a globular expansion at one end, and to have a mean length of about 1500 Å. The molecule of human cardiac myosin was found to be morphologically similar to myosin molecules from canine cardiac muscle and rabbit skeletal muscle.

Fine structure of the nevus cell

The purpose of this investigation was to characterize the fine structure of the nevus cell and to demonstrate, if possible, a unique premelanin granule. The presence of this granule in the nevus cell would substantiate the relationship between the nevus cell and the melanocyte. Biopsy specimens of dermal nevi with and without ultraviolet light stimulation were studied with an electron microscope and the following conclusions were reached: (1) The fine structure of the nevus cell is comparable to that of the melanocyte. (2) The premelanin granule or melanosome is present in the nevus cell, particularly after prolonged ultraviolet light stimulation. (3) The nevus cell is probably an embryonal cell that can differentiate with appropriate stimuli.

Evidence for Translocation of Iron in Plants

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