Synthese der Hämolymphproteine und die Aufnahme der Dotterfraktion in die Oocyte unter Actinomycin-Einflu\ (Untersuchungen anMusca domestica)

Zusammenfassung Mit Hilfe von autoradiographischen und elektrophoretischen Methoden wurde die Dottereinlagerung in den wachsenden Oocyten vonMusca domestica untersucht. Sie beginnt nach 30 min im Autoradiogramm sichtbar zu werden. Durch ihre Färbbarkeit und Markierung konnte die Dotterfraktion im Pherogramm von Ovar und Hämolymphe eines mittleren Wachstumsstadiums (Stadium 3) nachgewiesen werden. Nach Abschlu\ der Vitellogenese tritt sie in der Hämolymphe nicht mehr auf. Die Einlagerung der Dotterproteine wird durch Actinomycin gestört, dagegen läuft ihre Synthese nahezu unbeeinflu\t weiter. Die Transporthemmung kann als bisher unbekannter Nebeneffekt des Actinomycins gedeutet werden.

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Synthesis of haemolymph proteine and the uptake of the yolk fraction in the oocyte during Actinomycin-treatment. (Studies onMusca domestica)

Summary By means of radioautographic and electrophoretic techniques yolk protein uptake in the growing oocytes ofMusca domestica was investigated. After 30 min yolk protein becomes visible in the radioautograms. By stainability and labeling the yolk fraction could be demonstrated in the pherogram of ovary and haemolymph in an intermediate developmental stage (stage 3). After the end of vitellogenesis it does not appear in the haemolymph. The yolk protein uptake is inhibited by Actinomycin, but the synthesis goes on nearly as normal. This inhibition can be interpretated as a new accessory effect of Actinomycin.

     

Water relations of xerophilic fungi isolated from prunes

The predominant spoilage fungi of dried and high-moisture prunes were members of the Aspergillus glaucus group and Xeromyces bisporus. Chrysosporium spp. were also important. At the mean pH of prune flesh (3.8) and at 25 C, X. bisporus grew at water activities (a_w) down to 0.605, and Chrysosporium fastidium grew to 0.686. Germination was always followed by growth, but within the 120-day incubation period, the minimum a_w permitting asexual sporulation was usually higher than that permitting germination. Sexual sporulation often required an even higher a_w. The water requirements of aspergilli were appreciably greater at this pH than near neutrality, no species germinating below 0.738 a_w. This was probably a consequence of a high spore-death rate during incubation at low a_w and pH.     

Zum Bewegungssehen des Mehlkäfers Tenebrio molitor

Summary The locomotory turns of the beetle Tenebrio molitor were recorded from free walking animals which were held in stationary position and orientation by means of a tread compensator. Striped patterns revolved around an animal elicit optomotor responses which undergo an inversion at smaller stripe widths. The position of the inversion point characterizes the resolving power of the motion detectors, and corresponds to a 6.5° average angle between the optical axes of interacting elements in the motion detecting device. This indirectly determined value is consistent with the anatomically measured 7° average angle between the axes of neighbouring ommatidia in the Tenebrio compound eye.     

Comparative cytological study of Phasianus colchicus,Meleagris gallopavo,and Gallus domesticus

Summary Since viable intergeneric hybrids between the chicken (Gallus domesticus) and the pheasant (Phasianus colchicus) have been reported, as well as interfamilial hybrids between the chicken and the turkey (Meleagris gallopavo), the chromosome complements of the pheasant and the turkey were compared with that of the chicken. In these three species belonging to the order Galli, the Z-chromosomes appeared to be identical, while the autosomal complements of the pheasant and the turkey differed radically from that of the chicken. It was noted with some surprise that the pheasant of the family Phasianidae and the turkey of the family Meleagridae have very similar chromosome complements, at least so far as gross morphology of somatic metaphase chromosomes is concerned.This work was supported in part by grant C-5138 from the National Cancer Institute, U.S. Public Health Service, and grant C-17601 from the National Science Foundation.The authors gratefully acknowledge the generosity of Rea's Game Birds, Paramount, California, who supplied the pheasant chicks, and the McPherin Hatcheries, Sunnymead, California, who furnished the turkey chicks. The authors also appreciate the editorial assistance of'Patricia A. Ray.     

Cold hardiness in the two-spotted spider mite (Tetranychus urticae Koch)

Summary The effect of temperatures below 0° C on different stages of the two-spotted spider mite, and in particular on active adult females, has been investigated.Survival of active females at-5° was higher at approximately 100% relative humidity than at a lower degree of humidity. Higher rates of survival were also caused by acclimation of active females and larvae for one day at +5° before storage at-15°. No differences in cold-hardiness were found in active females from an organophosphorous resistant strain and a susceptible strain, and the ability to survive depended on the time-temperature exposures (see Fig. 3).Eggs were killed very rapidly at-15° C, while larvae survived longer exposures than active females. Compared at the LT₅₀ level females in diapause survived three times the exposure endured by acclimated active females.Supercooling points measured at a rate of cooling of 2° C per minute were highest in diapausing females and lowest in eggs. Acclimation had no effect on the supercooling points of active females. All stages were killed by freezing. It seems likely that the difference in survival between acclimated and not acclimated active females at-15° is caused by different ability to live in a supercooled state.

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Zusammenfassung Es wurde die Wirkung von Temperaturen unter 0° auf verschiedene Stadien der Bohnenspinnmilbe, insbesondere auf aktive erwachsene Weibchen untersucht.Die Überlebensrate aktiver Weibchen war bei nahezu hundertprozentiger relativer Luftfeuchtigkeit höher als bei niederer Feuchtigkeit. Höhere Überlebensraten wurden auch durch Akklimatisation aktiver Weibchen und Larven für einen Tag bei 5° vor der Behandlung mit-15° erreicht. Es wurden keine Unterschiede in der Kältewiderstandfähigkeit aktiver Weibchen eines phosphorsäureesterresistenten und eines anfälligen Stammes gefunden. Die Überlebensfähigkeit hängt von Dauer und Temperatur der Einwirkung ab.Eier wurden von-15° sehr schnell abgetötet, während Larven längere Einwirkungszeiten überlebten als aktive Weibchen. Bei einem Vergleich der LT₅₀ überlebten diapausierende Weibchen dreimal längere Einwirkungszeiten, als sie von akklimatisierten aktiven Weibchen ertragen wurden.Unterkühlungspunkte—gemessen bei einer Abkühlungsrate von 2° pro Minute—lagen bei diapausierenden Weibchen am höchsten und bei Eiern am niedrigsten.Akklimatisierung hatte keinen Einfluß auf die Unterkühlungspunkte aktiver Weibchen. Durch Gefrieren wurden alle Stadien getötet. Es erscheint möglich, daß der Unterschied im Überleben akklimatisierter und nichtakklimatisierter Weibchen bei-15° durch die verschiedene Fähigkeit bedingt ist, in einem unterkühlten Zustande zu leben.

     

Electron Microscope Study of the Human Neuromuscular Junction

A preliminary electron microscope study of human neuromuscular junction is presented. The biopsy material was taken from the palmarus longus, and fixed routinely in osmium tetroxide and embedded in methacrylate. The structure of the motor endings and the relationship of the synaptic vesicles to the axolemmal membrane are described. The synaptic clefts are filled with an homogeneous material in continuity with the basement membrane covering the muscle fiber. The subneural apparatus is described, and special attention is paid to a vesicular component present in the sarcoplasm of the junctional area, which differs from synaptic vesicles and is presumed to be a derivate of the sarcoplasmic reticulum.     

Bellevalia ciliata (Cyr.) Nees (Hyacinthaceae) neu für Bulgarien

(Bellevalia ciliata was recorded in north-east Bulgaria south of the Dobrudsha, within field and steppe vegetation. Vegetation records and a distribution map are presented. Based on taxonomic studies it is proposed to combineB. ciliata, B. sarmatica (Pall.) Wor. andB. speciosa Wor. under the oldest nameB. ciliata (Cyr.) Nees.     

Decreased Protein Kinase C Activity During Cerebral Ischemia and After Reperfusion in the Adult Rat

The possible activation of protein kinase C (PKC) during total cerebral ischemia was investigated in the rat. Translocation of PKC activity from the soluble to the particulate fraction was used as an index of PKC activation. There was a drop in the proportion of particulate PKC activity from 30% for controls to 20% by 30 min of ischemia (p less than 0.01). By 20 min of cardiac arrest, there was a 40% decline of the total cellular PKC activity (p less than 0.01). This was not accompanied by an increase in activator-independent activity, a finding indicating PKC was not being converted to protein kinase M. These data suggest that PKC was not activated during ischemia, but rather that ischemia causes a reduction in cellular PKC activity. Translocation of PKC activity to the particulate fraction was not observed in the cerebral cortex or hippocampus of reperfused brain for up to 6 h of recovery following 11-13 min of total cerebral ischemia. The level of total, soluble, and particulate PKC activity in the cerebral cortex was reduced (p less than 0.05), corresponding to the decrease observed by 15 min of ischemia without reflow. A similar decline in activity was also observed in the hippocampus. No increase in activator-independent activity was observed. These data suggest that PKC was inhibited during cerebral ischemia and that this reduced level of PKC activity was maintained throughout 6 h of recovery. We conclude that pathological activation of PKC was not responsible for the evolution of ischemic brain damage.