Zum Mechanismus der biologischen 24-Stunden-Periodik

Summary Using the physical and mathematical basis given in two foregoing papers, a differential equation is proposed for a model of the biological 24-hour-periodicity. This oscillation equation contains two characteristic non-linearities describing the self-sustaining property and the circadian rule. The right side of the equation (external force) represents the controlling environmental conditions, mainly the intensity of illumination. Solutions were obtained for different environmental conditions using a digital computer.Under constant conditions the solution of the equation describes oscillations self-sustained within a certain range of environmental conditions. In this range the oscillations fulfil the circadian rule, e.g. for light-active organisms: The frequency and the mean value of the oscillation increase with increasing light intensity; with an additional (arbitrary) threshold separating activity time and rest time for describing an activity rhythm, the (activity time rest time) ratio and the total amount of activity also increase.Under periodically changing environmental conditions five properties of the Zeitgeber used (two distinct intensities with twilight transitions) are variable and varied: The range of oscillation of the Zeitgeber, its frequency, its mean value, its L D ratio (time relation of light time and dark time), and the duration of the twilights. The most important of the examined properties was the phase angle difference between the (forced) oscillation and the (forcing) Zeitgeber. The general result for light-active organisms was: The phase of the oscillation advances relative to the Zeitgeber (in sofar as the oscillation is synchronized) if the period of the Zeitgeber, or its mean value, or its LD ratio, or the duration of the twilights increase. In dark-active organisms, the relation between phase angle difference and the mean value or the LD ratio is reversed. Exceptions to this general rule exist in the relation between phase angle difference and L D ratio if the free running period of the oscillation deviates too much from the period of a weak Zeitgeber (mainly in dark-active organisms) or if the duration of the twilights is too short (especially if the transitions are rectangular).Single exposures to light (or darkness) during constant conditions result in phase shifts depending in direction and amount on the phase of the oscillation at which the disturbance occured. The resulting response curves depend in range and form on the one hand on the time of measuring the phase shifts (either immediately or after several periods — in the steady state — following the disturbance) and, on the other hand, on the intensity of the initial illumination, on the duration, and on the intensity of the exposures, each in a different manner. Moreover, response curves effective in LD conditions deviate from those measured under constant conditions; the reason being the difference in the energy state of the oscillations in the two conditions. Therefore, it is impossible to derive the phase angle difference between the oscillation and a Zeitgeber in self-sustained oscillations from the measurement of response curves alone.The oscillation equation used contains only one free parameter, the frequency coefficient. If this coefficient is changed, the equation describes other biological rhythms. For instance, with a high value it describes the behaviour of single nerve cells, and that not only in cases of spontaneous rhythmicity (e.g. receptor cells) but also in cases of reactions to single or rhythmic stimuli. Moreover, the derived characteristics of the equation — especially the non-linearities — seem to be significant for other biological problems such as control mechanisms.     

Zum Mechanismus der biologischen 24-Stunden-Periodik

Summary The biological 24-hour-periodicity is based upon an endogenous (self-sustained) oscillation which is synchronized with the earth's rotation by periodically changing factors of the environment, primarily by the alternation of light and dark. These external Zeitgebers affect the phase of the endogenous oscillation. Theoretically, there are four different simple types of phase-control; all complicated types are combinations of these four types. In model experiments the behaviour of an oscillation in each of the four cases of phase-control is clearly demonstrated.The comparison of model experiments and biological experiments suggests that in organisms a specific combination-type of phase-control occurs. In this combination-type, a change in frequency is always positively correlated with a change in average level of the oscillation. Both parameters of the oscillation increase in light-active organisms and decrease in dark-active organisms with increasing light-intensity (circadian rule). In organisms both parameters are coupled by means of non-linear elements.The differential equation describing the 24-hour-periodcity is characterized by certain non-linearities. One of these makes the oscillation self-sustained and simultaneously couples the frequency of the oscillation to the average level, in the sense postulated by the circadian rule. The magnitude of the non-linearity is such that the resulting oscillation is intermediated between a harmonic and a relaxation type of oscillation, but has more characteristics of a harmonic oscillation. A second non-linearity which also couples frequency and level positively concerns the energy of recoil.All general properties of the biological 24-hour-periodicity can be reproduced by the described oscillator model. Some special properties (e.g. pattern) are more easily understood by the assumption of two coupled oscillators; the second oscillator, following the same general laws described above, is controlled by the first one. The oscillator hypothesis can be applied to biological periodicities with other frequencies; in general, the higher the frequency of a system the more the oscillation tends towards a relaxation type of oscillation.     

Zum Mechanismus der photodynamischen Inaktivierung von Saccharomyceszellen

Summary We have been shown that photodynamic damage in cells ofSaccharomyces caused by thiopyronine and also very probably by acridine yellow, thionine, trypaflavine, acridine orange, methylene blue and neutral red is due to aninterior effect where the dye enters the cell and attaches itself to important components of the cell — probably DNA or RNA — absorbing light energy and transfering this to these attached components.In the case of methyl green, malachite green and pyronine the low degree of inactivation caused by these dyes is explained by their poor ability to enter the cell and for lactoflavine (riboflavine) by its low light absorption. The relatively small photodynamic effect of brilliantcresyl blue is probably due to the low energy transfer from the dye to the attached component. We have further been able to show that for eosine this process ofinterior action is only a part of the explanation of this dye's action. The photodynamic effect of eosine is explained chiefly byexterior action. However theinterior effect of eosine can be increased by increasing the incubation time of the cells in eosine solution before exposing the cells to the light.

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FrauIngrid Pietsch danken wir für zuverlässige Assistenz bei der Durchführung der Versuche, der Deutschen Forschungsgemeinschaft für eine Sachbeihilfe.

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8. Mitteilung über photodynamische Wirkung von Farbstoffen.     

Zum Mechanismus der stoffwechselbedingten Vakuolenfluorochromierung mit Uranin

Zusammenfassung Es wird chromatographisch und spektrometrisch gezeigt, daß der Farbstoff Fluoreszein bei der Umlagerung vom Protoplasma zur Vakuole eine chemische Änderung erfährt. Diese dürfte mit großer Wahrscheinlichkeit eine Veresterung mit Essigsäure sein. Es wird vermutet, daß dieser Ester durch Reaktion von Fluoreszein mit Acetyl-Coenzym A entsteht.

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On the mechanism of the metabolically dependant uraninfluorochroming of vacuoles

Summary It is proofed by chromatographic and spectrometric observations, that the dyestuff fluorescein is chemically changed during the translocation from protoplasma to the vacuole. One may assume, that an esterification with acetic acid takes place. The fluorescein is supposed to be esterfied by the action of acetyl-coenzyme A.

     

Zum Mechanismus der Strahlenwirkung auf den K+-Na+-Austausch in Erythrozyten

Zusammenfassung Die von uns durchgeführten Untersuchungen an menschlichen und Tiererythrozyten lassen annehmen, daß es sich bei dem Verlust der Kaliumionen bzw. der Zunahme der Natriumkonzentration gleichzeitig um das Ergebnis der Strahlenwirkung auf die Zellmembran (Entladungseffekte) als auch auf den Stoffwechsel der Zelle handelt, wobei Stoffwechsel und Membranpermeabilität in Abhängigkeit von der Wiederaufladung in Wechselbeziehung stehen.Nach einem Vortrag gehalten auf dem II. Internationalen Kongreß für Biophysik vom 5. 9.–9. 9. 1966 in Wien.     

Zum Mechanismus der Diploidisierung in der Wirbeltierevolution: Koexistenz von tetrasomen und disomen Genloci der Isocitrat-Dehydrogenasen bei der Regenbogenforelle (Salmo irideus)

Zusammenfassung Beim Hering und bei der Regenbogenforelle finden sich genetisch determinierte Polymorphismen für die Überstands-(S-) und die mitochondriale (M-)Form der NADP-abhängigen Isocitrat-Dehydrogenasen (IDH). Beide Enzymformen verhalten sich wie dimere Moleküle. Beim Hering ist für beide Formen auf jeweils einen Genlocus mit 2 Allelen zu schließen. Entsprechend der tetraploiden Herkunft sind bei der Regenbogenforelle individuelle Genloci gegenüber dem Hering verdoppelt. Für die M-Form der NADP-IDH existieren bei dieser Forelle 2 verschiedene Genloci; an einem der beiden loci wurden 2 Allele gefunden. Für die S-Form ist nur 1 Genlocus mit 4 Allelen nachweisbar. In einer Stichprobe von 135 Individuen fanden sich 9 verschiedene Phänotypen, darunter 3 mit einer 3-Allelen-Kombination. Dieser Befund ist interpretierbar unter der Annahme eines tetrasomen Erbganges für die S-IDH. Der Mechanismus der Diploidisierung phylogenetisch tetraploider Organismen wird im Hinblick auf die Säugerevolution diskutiert.

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The mechanism of diploidization in vertebrate evolution: Coexistence of tetrasomic and disonic gene loci for the isocitrate dehydrogenases in trout (Salmo irideus)

Summary In the herring (Clupea harengus) and trout (Salmo irideus), the supernatant (S-) and mitochondrial (M-)form of the NADP-dependent isocitrate dehydrogenases (IDH) exhibit genetically determined polymorphisms. Both enzyme forms behave as dimeric molecules. In the herring, for each form, it can be inferred that 1 gene locus with 2 alleles exists. According to the tetraploid origin of the trout, individual gene loci are duplicated as compared to those of the herring. For the M-form of the enzyme, 2 different gene loci exist in the trout; at 1 of these loci 2 alleles were found. For the S-form only a single gene locus can be demonstrated. In a random sample of 135 individuals, 9 different phenotypes were observed, among which 3 exhibited a 3-allele combination. This finding can be interpreted, assuming a tetrasomic inheritance of the S-form IDH. The diploidization mechanism of phylogenetically tetraploid organisms is discussed with respect to mammalian evolution.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Die Grundlangen der biologischen Konstitutionslehre

Ohne Zusammenfassung