Zum Sauerstoffverbrauch von Myzus persicae (Sulz.) vor und nach Aufnahme des Blattrollvirus

Zusammenfassung Der Sauerstoffverbrauch virusfreier Myzus persicae (Sulz.) wird mit demjenigen blattrollvirusinfizierter Läuse verglichen. Der O₂-Verbrauch ist bei infizierten Tieren um rund 30% gegenüber virusfreien Kontrolltieren erniedrigt. Auf verschiedenen. Wirtspflanzen gehaltene Läuse zeigen keinen signifikanten Unterschied in ihrer Atmungsintensität. Die grö\te Erniedrigung des O₂-Bedarfs ist etwa 30 Stunden nach Ende des Infektionssaugens (d.h 38 Stunden nach Beginn der Nahrungsaufnahme) erreicht und steigt dann im Verlauf der folgenden 50 Stunden nicht weiter an. Der Stoffwechsel der Läuse wird offensichtlich durch die Aufnahme des Blattrollvirus gestört.

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Summary The intensity of respiration of virus-free aphids was compared with that of the same insects infected with potato leafroll virus. The former showed an average oxygen-consumption of 3.018 cm³/gm/hour, and the latter 1.992 cm³/gm/hour; which indicates a reduction of 33.9% in the oxygen-uptake in the infected animals. This reduction is associated with the infection and the multiplication of the virus in the insect. The oxygen-consumption was the same before the beginning and at the end of the infective suction period, falling afterwards over a period of 30 hours by about 30% of the first reading, and then remaining almost constant. This indicates a correlation between this variation in the oxygen-consumption and the multiplication of the virus in the aphid.

     

The pedicled transposition of the digastric and stylohyoid muscles in the treatment of velopharyngeal incompetence. Anatomic basis and clinical application]

The anatomical basis for the application of neurovascular pedicled muscle transfers of the digastric and stylohyoid muscles in the treatment of velopharynx incompetence is described. The fact that the neurovascular pedicle is located in the cranial third of the muscle bellies provides the safety of the operative procedure. The muscles have to be dissected with respect to that. The direction in which the transferred muscles pull is described. The muscle transposition is combined with the classic Wardill-Kilner operation to lengthen the soft palate. The transferred muscles have to avoid scar contraction and shortening of the soft palate and to gain a muscular function of the soft palate. The clinical use is justified in rare cases as demonstrated in one case.     

Slow heat rate increases yeast thermotolerance by maintaining plasma membrane integrity.

Thermal resistance of Saccharomyces cerevisiae was found to be drastically dependent on the kinetics of heat perturbation. Yeasts were found to be more resistant to a plateau of 1 h at 50 degrees C after a slope of temperature increase (slow and linear temperature increments) than after a shock (sudden temperature change). Thermotolerance was mainly acquired between 40-50 degrees C during a heat slope, i.e., above the maximal temperature of growth. The death of the yeasts subjected to a heat shock might be related to the loss of membrane integrity: intracellular contents extrusion, i.e., membrane permeabilization, was found to precede cell death. However, the permeabilization did not precede cell death during a heat slope and, therefore, membrane permeabilization was a consequence rather than a cause of cell death. During a slow temperature increase, yeasts which remain viable may have time to adapt their plasma membrane and thus maintain membrane integrity.     

The lysosomotropic agent monodansylcadaverine also acts as a solvent polarity probe.

The autofluorescent substance monodansylcadaverine has recently been reported as a specific in vivo marker for autophagic vacuoles. However, the mechanism for this specific labeling remained unclear. Our results reveal that the common model of ion trapping in acidic compartments cannot completely account for the observed autophagic vacuole staining. Because autophagic vacuoles are characterized by myelin-like membrane inclusions, we tested whether this lipid-rich environment is responsible for the staining properties of monodansylcadaverine. In in vitro experiments using either liposomes or solvents of different polarity, monodansylcadaverine showed an increased relative fluorescence intensity in a hydrophobic environment as well as a Stokes shift dependent on the solvent polarity. To test the effect of autophagic vacuoles or autophagic vacuole lipids on monodansylcadaverine fluorescence, we isolated autophagic vacuoles and purified autophagic vacuole lipids depleted of proteins. Entire autophagic vacuoles and autophagic vacuole lipids had the same effect on monodansylcadaverine fluorescence properties, suggesting lipids as the responsible component. Our results suggest that the in vivo fluorescence properties of monodansylcadaverine do not depend exclusively on accumulation in acidic compartments by ion trapping but also on an effective interaction of this molecule with autophagic vacuole membrane lipids. (J Histochem Cytochem 48:251-258, 2000)     

Osteogenic precursor cells in repair osteogenesis

Histological and electron-microscopic radioautographic investigations of regenerating medullar tissue were performed in rabbits following curettage. Low differentiated connective tissue cells were shown to possess the highest proliferative activity. DNA synthesis mainly took place in low differentiated, endothelial and osteogenic cells. It is suggested that low differentiated cells take part in histogenesis of regenerating medullar tissue, including osteo- and angiogenesis.