Zur reproduzierbarkeit der Rf in der Dünnschicht-Chromatographie

Summary Conditions are discussed which influence Rf¹ on thinlayer chromatograms, and directions are given to guarantee good reproducibility. Variance of Rf on thinlayer chromatograms is of the same order of magnitude as on paper chromatograms.

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Der Ausdruck Rf-Wert ist bei häufiger Wiederholung umständlich. Wir gebrauchen an seiner Stelle: das Rf (Singular), die Rf (Plural).

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Die Mittel zur Durchführung dieser Arbeit verdanken wir Arbeitsbeschaffungskrediten des Bundes (M.B.) sowie einer Studienbeihilfe vom Land Baden-Württemberg (A.N.).     

Benützung der oszillographischen Polarographie in der Mikrobiologie

Summary Oscillographic polarography with alternating current was used for following the course of utilisation and metabolism of some amino acids, purine and pyrimidine bases, similarly as their nucleosides and nucleotides in the washed suspensions of resting cells and in growing cultures ofEscherichia coli. The Polaroscope P-524 was used with mercury dropping electrode. The method was described for the oscillopolarographic investigation of activity of some bacterial enzymes, as for example: asparaginase, some nucleodesaminases and enzymes involved in the cleavage of nucleosides.     

Neue Anwendungen der Dünnschichtchromatographie

Ohne Zusammenfassung     

Über die Zytologie der Parthenogenese und der Geschlechtsbestimmung bei der GallmückeOligarces paradoxus Mein

Summary InOligarces paradoxus, the chromosomal behaviour was compared during pedogenetic development of and . The -egg undergoes a single non-reductional maturation division, the -egg shows two divisions which result in reduced nuclei. After maturation in the -egg, the number of chromosomes is restored by endomitosis. The nuclei of germ-line cells contain a high number of chromosomes (: 74\2-82; : at least 58) in both sexes. In somatic nuclei, the number is diminished by elimination to 10 in , to 5 in .     

Begründung für die Verschmelzung der Reichsanstalt für Mass und Gewicht mit der Physikalisch-Technischen Reichsanstalt in Berlin im Jahre 1923

Zunächst wird mit der Entstehung sowie dem Ausbau der beiden Reichsanstalten bis zum Jahre 1922 historisch eingeleitet, wobei über die Reichsanstalt für Mass und Gewicht als die meist unbekanntere etwas ausführlicher berichtet wird. Die Begründungen für oder gegen eine Verschmelzung werden danach aus der Sicht der beiden Reichsanstalten, der Eichbehörden der Länder des Deutschen Reiches, der Industrie, verschiedener Ausschüsse des Deutschen Reichstages und schliesslich der zuständigen Ministerien der Deutschen Reichsregierung angeführt. Mit einem kurzen Blick auf die inflationsbedingten Probleme des deutschen Alltags von Ende 1923 wird der Aufsatz durch eine Beurteilung des vor 53 Jahren geschehenen Zusammenschlusses aus dem Geschehen eben dieser 53 Jahre abgeschlossen.     

Befunde aus der Frühentwicklung des Rattenkeimes als Beitrag zur Rhythmik der Entwicklung

Summary On the fourth day of development of the rat embryo all of the stages are found from the two-cell stage to the blastocele stage even among embryos from the same litter. On the seventh day, they all show egg-cylinder stages without exception. The time interval between cleavages from the second to the sixth day of development is not constant and, in fact, varies over a wide range, even among embryos from the same litter.     

Über die Entstehung spezifischer bioaktiver Stoffe in der frühembryonalen Entwicklung der Tiere

Summary The autor studied the reaction of stage ontogenins with different proteids, isolated from the embryos at the moment of formation of the respective ontogenin. Not all fractions (least of all the yolk) fix the ontogenins. The DNA-proteids fix them; such a mixture specifically stimulates the development. In these mixtures, new substances are discovered: Ontogens.     

Untersuchung antileukämischer Substanzen an der Hühnerleukose

Summary In leukosis of chickens caused by administration of 1-m-Tolylsemicarbazide (Maretin-Bayer) Butzolidin caused a reduction of the number of leucocytes to normal values. This action might be attributed to a cytostatic effect of Butazolidin.     

Unterliegt die Heimkehrgeschwindigkeit der Brieftauben hormonalen Einflüssen?

Summary The relation between the homecoming-speed of carrier-pigeons and the influence of sexhormones and prolaktin is reported.It is further examined whether the influence of prolaktin (breeding on 10–15 days old eggs) or psychological factors (feeding of young individuals of more than 15 days) are the factors, accelerating the homecoming-speed. Best results are obtained by combining breeding 1–6 days old eggs and feeding young pigeons of 2–3 weeks.

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In memoriam Heinz Knieriem zu seinem 15. Todestage     

Dünnschichtchromatographischer Nachweis der Aminosäuren im Urin

Summary Urinary amino acids are converted into DNP-derivatives. Extraction by organic solvents yields both ether- and acid-soluble DNP-derivatives in a form suitable for separation and identification by thin-layer chromatography. Solvent systems and techniques for the detection of 35 urinary constituents are described. The method is applicable to the qualitative analysis of other biological fluids.     

Untersuchungen über die Biosynthese der Vitamine der Folsäuregruppe bei grünen Pflanzen

Résumé Des plantules de Pisum sont cultivées aseptiquement en milieu synthétique. A la lumière, elles synthétisent plus de facteurs du groupe de l'acide folique, déterminés par voie microbiologique, et plus d'acide ascorbique qu'à l'obscurité. L'adjonction d'acide ascorbique au milieu des plantes cultivées à l'obscurité compense partiellement l'absence de lumière.     

Zeitbedarf der Längsteilung von miteinander verzwirnten Fadenmolekülen

Summary The time requirement is treated for a longitudinal fission by Brownian movement of a very long particle consisting of two or more filaments twisted a great number of times round each other to form a double spiral. It is shown that a comparatively swift disintegration is obtained by partial rotation or torsion round the axis of the spiral, resulting in a loosing of the spiral structure and subsequent separation of the constituents by translational Brownian movement. The time required to separate a double spiral consisting of about 900 turns of a height of 3.4 × 10⁻⁷ cm and a radius of 10⁻⁷ cm, thus having a length of 3 × 10⁻⁴ cm being realized approximately by deoxyribonucleic acid is found by this mechanism to be about 50 to 80 s. The time required to undo the same spiral by unwrapping it turn by turn would be about 150 days. The result of the considerations is related to observations published byAlexander andSteacy on deoxyribonucleic acid. An additional remark stresses the importance of stereochemical asymmetry for the practicability of the mechanism and therefore the importance of optical activity for the time requirement of such disintegrations or transformations of high polymer material occurring in living organisms.      

Die Bedeutung der Mitochondrienstruktur für die Zitronensäuresynthese

Summary Rat liver mitochondria proved to need a structural integrity for optimal citric acid synthesis. Structural impairment leads to an inhibition of the synthetic activity of the mitochondria, the degree of inhibition being inversely related to substrate concentration; it causes, however, no inactivation of the condensing enzyme. The dependence of this reaction upon the structural conditions is the consequence of an interaction between the two mitochondrial enzymes acetyl-CoA deacylase and condensing enzyme.     

Oxydation der Zucker durch Süssmandelemulsin (Rohferment nachHelferich)

Summary Emulsin (Rohferment ofHelferich) and similar enzyme preparations ofRosaceae-Amygdaloideae seeds have been found to exhibit a low but definite oxidizing activity towards aldohexoses in concentrated sugar solutions used for transglycosylation experiments.     

Zur Stratigraphie der säugetierführenden Schichten von Java

Summary According to recent geological and paleontological investigations thePithecanthropus-beds of Java are pleistocene in age. The examinations of the fossil mammalian faunæ of the island are of utmost importance for this age-determination and the following faunæ can be recognized:Tji Djolang-fauna: Middle Pliocene.Kali Glagah-fauna: Upper Pliocene.Djetis-fauna withPithecanthropus: Lower Pleistocene.Trinil-fauna withPithecanthropus: Middle Pleistocene.Ngandong-fauna withHomo neanderthalensis soloensis: Upper Pleistocene.Sampoeng-fauna with a primitive type of the Wedda-Dravida-Australoid group: Subrecent. — Micropaleontological examinations of smallerForaminifera from marine equivalents of thePithecanthropus-beds confirm the age-determinations based on mammalia. — Recent field investigations prove that the lower and middle pleistocenePithecanthropus-beds are distinctlyfolded by a post-middle-pleistocene movement; the upper pleistocene Ngandong-terraces are not folded at all.     

Zur Trennung der C19-Steroide des Harns im Dünnschichtchromatogramm

Summary By a change of method to thin-layer chromatography, it was possible to fractionate completely the 17-ketosteroids from urine extract in one run. The chromatography was done in a horizontal manner on plates of 200×550 mm.     

Zur Frage der entzündungshemmenden Wirkung des Phenylbutazon bei hypothyreotischen Ratten

Summary Following pretreatment of rats by 4-methyl-2-thiouracil the anti-inflammatory action of phenylbutazone on formalin edema is strongly diminuished.     

Elektronenmikroskopische Beobachtungen an den Hülsenarteriolen in der Milz des Hundes

Summary The endothelial cells of sheathed arterioles of dog spleen were found to contain an abundance of intracytoplasmic filaments about 80 Å in diameter. The endothelium is surrounded by a fenestrated clastin skeleton. The sheath cells show signs of phagocytosis. A possible vasomotor function of the endothelial cells is discussed.     

Die von den Leuchtzifferblättern herrührende Strahlendosis in der Schweiz

Summary In 24 persons, men and women, the gonade dose corresponding to a defined radium charge on the wrist, was measured. The - and -radioactivity of more than 300 watches and clocks was analysed and the average activities determined. The proportion of men and women in Switzerland wearing luminous watches or having luminous clocks, was statistically determined in function of age. For the whole of the Swiss population, thegenetic dose for a generation (30 years) amounts to 100 mr±25%.