Wachstum und Zellteilung beiUrospora

Zusammenfassung 1. Alle Zellen einesUrospora-Fadens sind teilungs- und streckungsfähig.2. Mit zunehmendem Alter der Pflanze verschiebt sich die Zone des stärksten Wachstums von der Spitze zur Basis.3. Längs eines Fadens bilden sich von Tag zu Tag wechselnde Teilungszonen aus.4. Im allgemeinen erreicht eine junge Zelle nach vier Tagen wieder die teilungsfähige Länge.5. Bei täglich 14stündiger Lichteinwirkung beginnen die Zellteilungen etwa eine Stunde vor dem Dunkelwerden und erstrecken sich — nicht gleichzeitig in allen Zellen — über fünf Stunden.6. Vor der Zellteilung ordnet sich ein Teil der Kerne in einer äquatorialen Gürtellinie an.7. Sämtliche Kerne einer Zelle teilen sich gleichzeitig. Ihre Anzahl wird durch die Zellteilung nicht verändert.8. Die Vermehrung der Kerne erfolgt durch freie, das heißt von der Zellteilung unabhängige Mitosen in Zellen, die noch nicht die teilungsfähige Länge erreicht haben.

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Growth and cell-division inUrospora

Cultures ofUrospora wormskioldii were used for studying growth and details of cell-division in this alga. In general, all cells of a filament are able to divide in a four-day-rhythm. During this period, the length of the filament nearly doubles. The zone of most active cell-division changes with the age of the plant, moving downward from the top to the base of the filament. The uppermost cells may become fertile while the basic ones continue to divide. Cell-division does not occur simultaneously in all cells of a filament. In a 14:10 hour rhythm of light and dark, divisions begin about one hour before the onset of the dark period and continue over the following five hours. In the growing cell, nuclei are distributed irregularly; before dividing, some of them arrange themselves in an equatorial line. All nuclei of a cell divide synchronously, the new wall differentiating from the uniting phragmoplasts of the neighbouring spindles. The number of nuclei does not vary because of cell-division; multiplication of nuclei in growing cells is brought about by mitosis without cell-division.

     

Indirekte Regelmechanismen der Stoffwechselgröße von Fischen

Metabolic rate does not strictly follow changes of influencing parameters. O₂-consumption by fish is ordinarily said to be independent from O₂-pressure throughout a wide range. This constancy is probably the result of a regulation. The metabolic rate itself or an auxiliary mechanism “before” or “after” metabolism may be regulated. On the basis of vanDam's paper (1938) and our own experiments, the problem whether or not O₂-pressure in blood serves as a regulated auxiliary mechanism in order to maintain a certain metabolic constancy is discussed. The disadvantage of such a regulation would be the energy demand of increased ventilation and circulation as compensating mechanisms. In accordance with this assumption we have found a rise in O₂-consumption at a somewhat reduced O₂-pressure. Locomotory behaviour supports the constancy of metabolic rate; thus a contrary shift of the temperature preferendum after application of substances which influence metabolism has been found.     

THE EFFECT OF THE INTERACTION OF TEMPERATURE WITH AFTER-RIPENING REQUIREMENT AND COMPENSATING TEMPERATURE ON GERMINATION OF SEED OF FIVE SPECIES OF ROSA

Seeds of 5 rose species, Rosa multiflora Thunb. ‘Cathayensis,’ R. × reversa Waldst. & Kit., R. setigera Michx. ‘Beltsville,’ R. setigera Michx. ‘Serena,’ and R. wichuraiana Crepin, varied in after-ripening requirement from 30 days at 4.4 C for R. multiflora to 90 days for R. setigera ‘Serena.’ The compensating temperature varied from near 12.8 C for R. × reversa to a value near 29.4 C for R. setigera ‘Beltsville.’ In this report compensating temperature is used to describe that temperature at which mature, moist seed does not germinate, after-ripening does not take place, and dormancy does not change. Seed germination was reduced by interruption of the after-ripening period with intervals at temperatures above the compensating temperature. The interruptions were more effective in reducing germination when more frequent and when the temperature during the interval was higher. Species differed in their sensitivity to high-temperature reduction of germination. Those having the longest after-ripening requirement were most sensitive. Germination of seeds which had the minimum after-ripening treatment was repressed more by high temperature than germination of those seeds which had an excess of after-ripening. The decrease in germination resulted from imposition of a secondary dormancy of the embryo, and probably also from reversal of the after-ripening effect upon the primary dormancy imposed by the seed coat.     

The Effects of Hypnotherapy on Homosexuality

Fifteen homosexuals were treated with hypnosis. The patients were selected from a general psychiatric practice and had a long history of confirmed homosexual behaviour and showed no evidence of organic or psychotic illness. The type of hypnotic induction attempted in all cases is described. In those where a satisfactory depth of hypnotic trance was achieved a change in sexual orientation was suggested to the patient.Before therapy, each patient was assessed using the Kinsey scale. Results were evaluated in terms of the patient''s subsequent behaviour and his subjective feelings. Of the 15 patients, three showed no improvement, four showed a mild improvement and eight showed a marked improvement. There was a significant correlation between the depth of hypnosis achieved and the therapeutic outcome. Those patients who reached a deep level of hypnotic trance were most likely to show a marked improvement. There were no significant correlations with other factors such as degree of homosexuality as measured on the Kinsey scale and the patient''s marital status.Treatment of homosexuals with hypnosis may produce more satisfactory results than those obtainable by other means. The best results are likely to be achieved in patients who are good hypnotic subjects.     

The Mechanism of Action of Splenic Irradiation in Chronic Myelogenous Leukemia

The mechanism of action of splenic irradiation in the induction of a remission in chronic myelogenous leukemia was investigated in six patients using a leukocyte kinetic approach. The leukocytes were labelled in vitro with radioactive diisopropylfluorophosphate-32 and returned to the circulation. The effect of treatment on the rate of change of leukocyte specific activity was determined. The results suggest (1) that irradiation of the spleen damages granulopoietic cells as they cycle back and forth between the spleen, blood and other extravascular compartments; (2) that damage to exchangeable granulopoietic cells in transit through the irradiated spleen may explain the long remission often encountered after this form of therapy.     

Der Einfluß des Lichtes auf die Temperaturadaptation beiRana temporaria

Zusammenfassung 1. Der Sauerstoffverbrauch adulter Grasfroschmännchen (Rana temporaria L.) wurde nach Anpassung an 7° und 23° C bei Langtag, Kurztag und Dunkelheit bei 23° C unter verschiedenen Beleuchtungsbedingungen untersucht (automatische Registrierung während 24 Stunden).2. Bei den vorher dunkel aufbewahrten Tieren zeigte sich eine Leistungsadaptation im Sinne einer Kompensation, bei den Langtagsfröschen fand sich ohne Veränderung der Lichtperiode eine entsprechende Adaptation nur bei den Nachtwerten.3. Für die Kurztagstiere ist die Versuchstemperatur von 23° C unnatürlich hoch. Damit mag die schwere Deutbarkeit der Kurven zusammenhängen. Nach den Befunden ist es wichtig, nicht nur die Lichtbedingungen der Vorbehandlung, sondern auch die während des Versuches konstant zu halten.4. Die Versuche geben Hinweise dafür, daß die bekannte Temperaturunabhängigkeit des circadianen Rhythmus durch eine rasche, nahezu ideale Kompensation zustande kommt.5. Die Exstirpation des Pinealorgans senkt die Werte für den Sauerstoffverbrauch und bringt die Leistungsadaptation zum Verschwinden.6. Der Sauerstoffverbrauch der Muskelhomogenisate von Tieren, die tags beleuchtet wurden, zeigt eine Leistungsadaptation im Sinne einer Kompensation.

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The influence of light on the temperature adaptation inRana temporaria

AdultRana temporaria L. males were acclimated to 7° and 23° C under long day, short day and continued darkness. Thereafter their oxygen consumption was measured at 23° C under different light conditions (automatic 24-hour registration). The individuals previously kept in darkness exhibited capacity adaptation in the sense of a compensation; long day acclimated frogs showed a respective adaptation, without change of light conditions, only in regard to the night values. For short day acclimated individuals, the test temperature of 23° C is unnaturally high. This fact may have affected our results and led to curves which are extremely difficult to interpret. The results obtained indicate that it is important to control the light conditions not only during the first acclimation period but also during the experiment proper. The experiments provide hints for the assumption that the known temperature independence of the circadian rhythm is based on a fast, almost ideal compensation. Extirpation of the pineal organ reduces oxygen consumption and causes the capacity adaptation to disappear. Oxygen consumption of muscle homogenates of individuals exposed to light during the daytime showed capacity adaptation in the sense of a compensation.

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Herrn Professor Dr.Friedrich Krüger zum 65. Geburtstag am 18. August 1967 in Verehrung gewidmet.     

Zum Ortungsverfahren von Gyrinus substriatus Steph

Zusammenfassung Die vorliegende Arbeit befaßt sich mit dem Orientierungsvermögen des Taumelkäfers (Gyrinus substriatus) im Bereich der Wasseroberfläche mit Hilfe der Antennenorgane.Der Taumelkäfer besitzt eine hohe Empfindlichkeit gegenüber Oberflächenwellen und ist in der Lage, deren Einfallsrichtung festzustellen. Im Nahbereich werden Hindernisse, die in die Wasserfläche eintauchen und einen Meniskus hochziehen, gut erkannt.Die mechanischen und elektrophysiologisohen Eigenschaften der Antennen werden ermittelt. Mechanische Erschütterungen rufen Relativbewegungen zwischen Pedicellus und dem frei in die Luft ragenden Flagellum hervor und erregen das Johnstonsehe Organ. Pedicellus und Flagellum sind als schwingungsfähiges System anzusehen, dessen Eigenfrequenz 250 Hz beträgt und dessen relatives Dämpfungsmaß etwa den Wert 0,7 hat. In dem in Frage kommenden Frequenzbereich bis 150 Hz arbeitet das Schwingungssystem vorwiegend als Beschleunigungsmesser.Die elektrophysiologischen Untersuehungsergebnisse stimmen gut mit den auf Grund der Schwingungsmessungen gefundenen Eigenschaften überein. In der vom Antennennerven abgenommenen elektrophysiologischen Signalspannung werden reizsynchrone Pulssalven beobachtet, denen sich bei steigender Erregungsfrequenz ein synchrones Summenpotential überlagert. Vergleiche mit den mechanischen Untersuchungsergebnissen zeigen, daß das Summenpotential seinen Ursprung im Johnstonschen Organ hat. Die Amplitude dieses Signals steigt proportional mit der Relativbewegung zwischen Flagellum und Pedicellus an; sie ist in einem weiten Bereich unabhängig von der Frequenz.Der Käfer ist in der Lage, äußerst feine Erschütterungen der Wasserfläche wahrzunehmen. Wasserwellen, deren Amplitude nur wenige m beträgt, bringen das Johnstonsche Organ zum Ansprechen. Die Empfindlichkeit nimmt mit steigender Frequenz zu. Hat der Käfer eine Eigengeschwindigkeit, die der Ausbreitungsrichtung eines Wellenzuges entgegengerichtet ist, so erkennt er diese Wellen auf Grund des Doppier-Effektes besser. Mit einer ähnlich guten Empfindlichkeit nimmt der Käfer in der Nähe von Hindernissen den Meniskus wahr. Die ansteigende Wasserfläche ruft infolge der Eigengeschwindigkeit des Käfers eine zeitlich sich ändernde Antennenauslenkung hervor. Bei normalen Schwimmgeschwindigkeiten ist sie bereits in der Entfernung von 0,5–1,5 cm vom Rand so groß, daß der Käfer reagiert.

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On the orientation of Gyrinus substriatus StephWhirligig beetle

Summary The orientation of whirligig beetles Gyrinus substriatus on the surface of water by means of the antennae has been investigated. Whirligig beetles are very sensitive to waves on the surface and are able to find out the direction from where the waves come. They are also able to perceive objects which dip into the water surface and form a meniscus.The antennae have been investigated mechanically and electrophysiologically. Mechanic percussions produce movements between the pedicellus and the flagellum which does not touch the surface of water (Figs. 2, 14). These movements excite the Johnston-Organ. Pedicellus and Flagellum form a vibration system; the resonance-frequency is about 250 Hz and the relative attenuation constant is about 0,7. In the interesting frequency range below 150 Hz the system is mainly measuring accelerations.The results of electrophysiological investigations show a good conformity with those found by mechanical measurements. In the electrophysiological signal, derived from the antenna nerve, groups of spikes are to be observed which are in synchronism with the exciting signal. By increasing the exciting frequency a synchronous sum potential appears which is superimposed upon the original signal (Figs. 19...21).Comparisons with mechanical investigations show that the sum potential has its origin in the Johnston-Organ. The amplitude of this signal increases proportionally to the relative motion between flagellum and pedicellus, independent of frequency in a wide range (Fig. 23).The beetle is able to perceive very small percussions of the surface of water. Waves on the surface with an amplitude of several m produce a response in the Johnston-Organ. The sensivity increases with increasing frequency (Fig. 31). If the beetle is moving against a train of waves, it will perceive them better by reason of the Doppler-Effect.The sensivity is similar when the beetle approaches the meniscus near objects. The inclined water surface produces an excursion of the antenna as a function of time depending on the velocity of the beetle. At normal velocities and in an distance of 0.5–1.5 cm this effect will be large enough to produce a response (Fig. 32).

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Der Verfasser dankt Herrn Prof. Dr.-Ing. habil. H. Tischner und Herrn Dr.-Ing. A. Schief für die Anregung zu diesen Untersuchungen und dem Herrn Ministerpräsidenten des Landes Nordrhein-Westfalen — Landesamt für Forschung — für die Bereitstellung der Mittel.