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Copyright of Zeitschrift für die Gesamte Neurologie und Psychiatrie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The development of the spore began at the sporoblast stage. The profile of the developing polar filament was defined clearly in the late sporoblast, but its internal structure was still lacking. During this stage, both a vesicular type of endoplasmic reticulum and an endoplasmic reticulum containing cisternae in a parallel arrangement were abundant in the cytoplasm of the sporoblast. Numbers of large, expanded vacuoles were also observed in the cytoplasm. As spore development proceeded, the spore coat increased gradually in thickness. The expanded vacuoles started to take up positions around the anterior portion of the polar filament and to become incorporated into the developing polaroplast, which eventually became a highly-laminated structure in the mature spore. In the mature spore, the fully-developed polar filament possessed a central tube surrounded by 12 cylindrical structures, and the spore coat attained its maximum thickness. [ABSTRACT FROM AUTHOR]

Copyright of Acta Neurochirurgica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The mature spore possesses a thick spore coat and a particle-bearing spore membrane. The highly laminated polaroplast membranes are located at the anterior pole of the spore. Close to its base, the polar filament is surrounded by the polaroplast membrane. The polar filament runs spirally towards the posterior pole of the spore. A large portion of the polar filament is arranged in two layers. A similar arrangement was also observed in immature spores and in the sporoblast stage, although it was not so orderly arranged in the latter. The developing polaroplast membrane was observed in the immature spore, but not in the sporoblast. The sporoblast wall is much thinner than the spore coat, but has the same texture. Endoplasmic reticulum is the most prominent cytoplasmic organelle in the developing stages of Nosema apis. Porous nuclear envelopes are also observed in developing stages. The role of the endoplasmic reticulum in the formation of the polar filament, polaroplast and spore coat, and the function of the spore membrane, are discussed. [ABSTRACT FROM AUTHOR]

Nosema michaelis spores possess a biologically unique external arrangement of microtubules. The microtubules were studied ultrastructurally with the use of thin sections, freeze-etched and negatively stained preparations. Tubules were sheared from the spores by repetitive freeze-thaw cycles and harvested by high speed centrifugation. Electron microscopic observations of negatively stained and freeze-etched samples revealed the globular subunit construction of the tubules. Suspensions of isolated microtubules and tubular fragments formed extended linear array at 4°C, apparently by autoaggregation. Tubule preparations were reduced and alkylated under various conditions and examined in several polyacrylamide disc gel systems. Two bands were obtained from completely reduced and alkylated microtubule proteins separated in polyacrylamide gels containing 8 M-urea, detergent-urea or detergent alone. The two subunit proteins (tubulins) had average molecular weights of ∼45000 and ∼53000. Incompletely reduced samples yielded two additional satellite bands of higher molecular weights, suggestive of homodimers. [ABSTRACT FROM AUTHOR]

A microsporidian parasite, Nosema sp., has been found in the epithelium of the vas deferens of the spider crab, Libinia dubia. Cells were heavily infected with developing and mature spores. The spore mother cell possesses a dikaryon. The nuclear membrane shows a simple form of nuclear pore. Within the nucleus microtubules of the intercellular mitotic spindle are observed. The sporont undergoes cytokinesis to form the early sporoblast. The sporoblasts possess a dikaryon., and a centriolar plaque may be observed at the nuclear surface. The polar filament develops in association with a modified Golgi apparatus, consisting of numerous cisternae frequently filled with electron dense material, sometimes surrounded by several layers of membrane. The polar filament is formed as two hollow tubes, the inner tube being eccentrically placed within the outer one. Preparations treated with the periodic acid-silver methenamine technique for the detection of complex polysaccharides show a positive reaction in the Golgi, the sperical masses and associated membranes and in the polar filament. The developing spore wall also shows a positive reaction. [ABSTRACT FROM AUTHOR]

The structure of the polar filament of a species of Nosema (Protozoa, Microspora) invading a sea horse, Hippocampus erectus, has been studied with the electron microscope. Filaments extruded from spores were examined on ultrathin sections and on negatively stained preparations. The extruded filament appears as a hollow tube whose walls are composed of membranes; mostly there are three membranes separated or closely joint together. There was no positive evidence of fibrillar structures in the extruded filaments. In a resting spore, the membranous walls of the filament, although less distinct, are also discernible. A collar-like structure at the base of the filament provides for the anchorage of the extruded filament, being firmly wedged in the aperture pierced in the spores shell by the filament discharge. In resting state this structure attaches the basal part of the filament to the organelle known as polar cap. No evidence was found of a 'terminal sac' at the loose end of the filament. During extrusion, sporoplasm passes through the cavity of the filament in an extremely elongated state. The empty space in the extruded spore shell is in fact the enlarged posterior vacuole. At the anterior end there is a separated space communicating with the filament cavity. [ABSTRACT FROM AUTHOR]

Gramicidin D and nigericin were found to stimulate K influx into oat roots. Valinomycin and nonactin had little effect on K influx. The region of the root most sensitive to gramicidin was the elongation zone. Monocot roots were more sensitive to gramicidin than dicot roots. At 0.2 mM KCl, gramicidin stimulated K influx by 4- to 8fold over a 30-min absorption period. Although a gramicidin response is detectable within one minute, maximum stimulation occurred after a slight (approximately 2-min) lag period. The gramicidin effect was much greater at 0.2 mM KCl than at 20 mM KCl. Respiratory inhibitors reduced the gramicidin-stimulated K influx by 50-80%. The results are discussed in terms of possible mechanisms of action of the various ionophores on ion transport in roots. [ABSTRACT FROM AUTHOR]