Densitometrische Bestimmung von Proteinen in kleinen Volumen

Summary An analytical method of quantitative determination of proteins in small volumes is described. The method is based upon the densitometric evaluation of colour tests in agar-gel. The quantity of proteins is determined by graphical integration of densitometric curves and, in the arrangement described, it is possible to assay proteins in volumes of the order 10^–3 ml.     

Untersuchungen an Bariumtitanat-Einkristallen

Summary It was possible to produce bariumtitanate monocrystals with ferroelectric qualities, which is shown in the temperature curve of the dielectric constant, in the resonance frequency, and also in hysteresis phenomena.     

Untersuchungen zur Verbreitung von Indolglucosinolaten in Cruciferen

Summary In etiolated seedlings of Cruciferae 49 out of 50 species contain indolglucosinolates. In this developmental stage the rate of Glucobrassicin biogenesis surpasses the synthesis of all other mustard oil glucosides. The meaning of these results for the chemodifferentiation of the Cruciferae is discussed.     

Untersuchungen an saponinhaltigen Homogenaten

Summary These investigations are a contribution to the study of problems caused by homogenisation. It is shown that saponines in homogenates of leaves of Viola tricolor really react with the suspended chloroplasts.     

Vergleichende Organellographie

Ohne Zusammenfassung     

Zytologische Untersuchungen an der Reblaus-Blattgalle

Summary Up to 9 types of cell nuclei, distinguished by their size, were found in the tissue of galls, which are produced by the vine louse. The growth of the cell nuclei probably proceeds in a series of prophase-like intermediate stages from one type of nuclei size to the next largest by means of endomitotic or endomitosis-like processes.     

Elektronenmikroskopische Untersuchungen an den Herzklappen

Summary The heart values of the rabbit were examined by electronmicroscope. The endothelium consists of a single layer of flat cells. Adjacent cells may overlap over extensive areas. The endothelial cells contain numerous tonofilaments. This structure is functionally and dynamically interpreted. The subendothelial connective tissue is called spongiosa. The fibrosa consists of bundles of collagenous fibres.     

Vergleichende Untersuchungen über die angeborene Grössenunterscheidung beiTilapia nilotica undHemihaplochromis multicolor (Pisces; Cichlidae)

Summary Female mouth-brooding Cichlid fishes pick up the young fry again when disturbed. The young, for their part, collect about the head of the mother fish and, contacting it, try to enter the mouth cavity. This contact behaviour is based upon an inborn readiness to react on the visual stimulus offered by the mother. Mother fishes inTilapia nilotica are much larger than those ofHemihaplochromis multicolor. By comparative experimental studies with models of various size (black balls of different diameters) it is shown that the young of the 2 species strictly prefer different sizes of the model, corresponding with the different sizes of the parent fishes.

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Herrn Prof.H. M. Peters zum 60. Geburtstag gewidmet.     

Untersuchungen über den Wirkungsmechanismus von Procarbazin (Natulan®)

Summary The cytotoxic methylhydrazine derivative procarbazine or Natulan® has a marked influence on the synthesis of deoxyribonucleic acid in Ehrlich ascites carcinoma cells. The incorporation of³H-thymidine into DNA — measured by autoradiographic methods — is inhibited.     

Interferenzmikroskopische Untersuchungen an Medulloblastom- und Glioblastomzellen

Summary The dry mass per unit area (g/µ²) for nucleus and cytoplasma was determinated by interference microscope from 1043 glioblastoma cells of 5 various glioblastomas and from 439 medulloblastoma cells of 4 various medulloblastomas. The values obtained from the glioblastoma cells are significantly higher than the values of medulloblastoma cells.

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Mit dankenswerter Unterstützung der Deutschen Forschungs gemeinschaft.     

Mikrohistoautoradiographische Untersuchungen über die Verteilung von tritiummarkierten Phenothiazinen im Auge

Summary Microhistoautoradiographic and radiometric investigations show that phenothiazines electively accumulate in the melanin-bearing structures of the eye, especially in the chorioid. Retinotoxicity is not only the effect of an accumulation of melanin, but also the consequence of the specific substance-toxicity and the biological importance of the chorio-capillaris which varies between the different species.     

Zytophotometrische Untersuchungen an normalen Lymphknotenzellen des Schafes

Summary Cytophotometric investigations of lymphocytic populations of 4 sheeps were carried out to determine the diploid standard value for comparative investigations of lymph node cells from sheep with lymphatic leucosis. Inspite of exact and simultaneous preparation there were marked and significant differences in the histograms as well as in the diagrams of absorption level separation. Therefore, the control of several normal cell populations is essential before starting cytophotometric investigations of neoplastic cells.

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Diese Arbeit entstand im Rahmen des Sonderforschungsbereiches 47 (Virologie) an der Justus Liebig-Universität Giessen.     

Elektrophysiologische Untersuchungen an der Seitenlinie vonXenopus laevis

Summary Electrophysiological recording of the spontaneous activity from a single group of lateral sense organs on the abdomen ofXenopus laevis results in a more or less regular series of large spikes, either all of the same height or of two different sizes (each group is innervated by two large lateralis fibres). Mechanical stimulation of such a group may cause a rise or a fall of spontaneous impulse frequency. There is evidence for a two-directional sensitivity of the same unit (nerve fibre) from a single group, out of the middle as well as out of the dorsal lateral line.     

Elektronenmikroskopisch-cytochemische Untersuchungen an der Kernmembran vonStreptotheca thamesis

Summary The nuclear envelope and nuclear pores of the diatomStreptotheca thamesis are described, concerning some ultrastructural and functional features. Treatment with DNAse or pepsine results in a partial breakdown of these organelles.     

Weitere Untersuchungen über den Parasitismus von Labyrinthula gegenüber Pilzen

Summary Labyrinthula could be isolated from marineCladophora algae in Cuba. These strains were very active against several fungi, causing diseases of plants or skin, likeFusarium oxysporum, F. moniliforme, F. vasinfectum, Pestalozzia sp.,Colletotrichum gloeosporioides, Trichophyton gallinae and destroyed the protoplasm of the hyphae by means of their parasitic activity.

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Diese Arbeit wurde am Centro Nacional de Investigaciones Cientificas, Habana (Kuba) durchgeführt und in dankenswerter Weise unterstützt.     

Vergleichende Untersuchungen über die Toxizität der Ca- und Zn(II)-Chelate der Diäthylentriaminpentaessigsäure

Summary The lethal effect of daily intraperitoneal administrations of Ca-DTPA and Zn(II)-DTPA was studied in mice. Due to recovery processes, single chelate doses are non-additive and the cumulative LD₅₀ increases with decreasing daily dosage. At a given number of administrations, Zn(II)-DTPA is 2.5 times less toxic than Ca-DTPA. However, if the daily dosage is kept constant and the number of administrations variable, Zn(II)-DTPA is 30 times less toxic.     

Enzymhistochemische Untersuchungen an durstaktivierten neurosekretorischen Zellen der Ratte

Summary In hypothalamic neurosecretory nuclei of rats subject to water withdrawl for 1–14 days, a marked increase in the activities of histochemically detected acid phosphatase, thiamine pyrophosphatase and glucose-6-phosphate dehydrogenase is observed. LDH and SDH activities do not change. Two different cell types can be distinguished by means of the acid phosphatase and TPPase reactions.     

Über optische Untersuchungen an Deckschichten auf Aluminium

Summary The double refraction of oxide films on Al conditioned by an electrolytic treatment of the metal in oxalic acid, sulphuric acid and so on (Eloxal-layers) is due only to the disperse structure of the film (Formdoppel-brechung), since the substances the film consists of are optically isotropic.The optical properties depend, excepting the formation conditions, in a very characteristic manner on the crystallographic orientation of the metallic surface.     

Elektronenmikroskopische Untersuchungen an den heterophilen Granulozyten des Haushuhns

Summary Ultra-thin sections of heterophil granulocytes of clinically healthy, laying hybrid-hens were examined by electron microscope. Within the cytoplasm of these cells, round, oval or fusiform granules (rods) of different electron density were found. Osmiophilic and electron light areas (cores) were seen, either together within the same granular body, or separately in different granules.     

Elektronenmikroskopische Untersuchungen an Zellulosefasern nach Behandlung mit Ultraschall

Summary Treating natural cellulose fibres with ultrasonic waves, fine fibrils split off, which easily can be studied with the electronmicroscope. Bundles of cellulose-molecules with various diameters, very frequently 60–70 Å wide, are found. Their length seems not to be limited within the fibres.