Degradation of polysaccharides containing uronic acid residues

A method for the selective degradation of polysaccharides containing uronic acid residues is described. It involves methylation of hydroxyl and carboxyl groups, base-catalysed elimination, and mild hydrolysis with acid. The degraded product is etherified with trideuteriomethyl or ethyl groups and hydrolysed, and the resulting mixture of etherified sugars is analysed, as the alditol acetates, by g.l.c.—m.s. Comparison of this analysis with the methylation analysis of the original polysaccharide gives information on the nature of the sugar residues on either side of the uronic acid residue.     

Enzymatic hydrolysis of n-substituted met-tRNA(M) and met-tRNA(F)

By addition of 1-(14)C-sodium acedate to the growth medium of Nocardia asteroides, it can be shown that the lipid content increases during the exponential phase, but does not vary during the stationary phase of the growth. Nocardic acid biosynthesis from the medium molecular weight fatty acids occurs chiefly during te stationary phase. As these compounds are localised in the cell walls, it becomes evident that the lipid envelope of the walls is still increasing when the cell growth and division have stopped.     

Lineare Systeme mit gesteuerten statistischen Impulsquellen

Summary From the communication engineers point of view the paper deals with networks consisting of linear filters and a special sort of controlled statistical pulse generators (SIG). The SIG responds to an analog signal with a sequence of Dirac impulses, where the probability for an output impulse at a given time depends on the instantaneous value of the input signal only. In connection with linear filters, however, systems can be realized in which the whole past of the input determines the statistical structure of the output. Therefore systems consisting of linear filters and SIGs (SIG networks) become interesting as models of biological systems, because in biological information processing transformations from analog signals into pulse trains occur very often. An example concerning the application of SIG systems in behavioural sciences will be discussed in a subsequent paper. In the present paper a theoretical analysis of the SIG and SIG networks is carried out by means of Statistical Communication Theory and Theory of Stochastic Processes. It is shown that under certain conditions very complex SIG networks can be treated with Correlation Theory. For one case not satisfying these conditions a solution on the base of Markoff processes is given.

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Auszug aus einer von der Fakultät für Maschinenwesen und Elektrotechnik der Technischen Hochschule München genehmigten Dissertation.Herrn Prof. Dr.-Ing. H. Marko danke ich für das Interesse und die fördernde Kritik während des Entstehens der dieser Arbeit zugrundeliegenden Dissertation. Der Deutschen Forschungsgemeinschaft ist für die finanzielle Förderung der Untersuchungen zu danken. Die numerischen Berechnungen wurden auf der Rechenanlage TR4 des Leibniz-Rechenzentrums der Bayerischen Akademie der Wissenschaften durchgeführt.     

A histochemically demonstrable thiaminepyrophosphatase activity in the sinusoidal endothelium of the liver

Summary A new histochemically demonstrable thiaminepyrophosphatase activity in liver tissue is described. It appears to be localized solely to the cytosomes of the sinusoidal endothelium. The activity, which requires high concentration of lead ion for its demonstration, has a high degree of substrate specificity. It resists formaldehyde fixation, ethanol and many inhibitors. The optimum pH is at pH 6.This study was supported in part by a grant from the Swedish Medical Research Council.     

Die Feinstruktur der peribronchialen Mikroparaganglien beim Meerschweinchen

Zusammenfassung Das Parenchym der peribronchialen Mikroparaganglien wird von zwei Zellarten aufgebaut: Chromaffine Zellen (Typ I-Zellen) und Hüllzellen (Typ II-Zellen).Die chromaffinen Zellen sind durch ihren reichen Gehalt an Vesikeln mit elektronendichtem Inhalt gekennzeichnet, deren Durchmesser 700–1300 Å beträgt. Markfreie Nerven ziehen an die Typ I-Zellen heran und bilden synaptische Kontakte aus. Die chromaffinen Zellen sind dabei der postsynaptische Teil der Verbindung. Die Hüllzellen entsprechen strukturell und funktionell den Schwannschen Zellen.Ein Mikroparaganglion wird von 10 bis 15 chromaffinen Zellen und deren Hüllzellen aufgebaut. Sie liegen dicht um fenestrierte Kapillaren, die von den Aa. bronchiales aus versorgt werden. Die Paraganglien sind von den Nervenzellen des peribronchialen Plexus durch dessen Perineurium getrennt. Selten findet man solitäre chromaffine Zellen innerhalb der Nervengeflechte. Es wird angenommen, daß die Paraganglien endokrine Funktionen erfüllen.

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The fine structure of the guinea pig peribronchial micro-paraganglia

Summary The parenchyma of peribronchial microparaganglia consists of two different cell types: chromaffin cells (type I-cells) and surrounding cells (type II-cells).The chromaffin cells contain numerous vesicles with electron dense content, their diameter ranging from 700 to 1,300 Å. Unmyelinated nerves form synapses with type I-cells. The surrounding cells structurally and functionally correspond to Schwann cells.A micro-paraganglion consists of ten to fifteen chromaffin cells and their satellite cells. They are situated close to fenestrated capillaries, which are supplied from the Aa. bronchiales. A perineurial sheath separates the paraganglia from the nerve cells of the peribronchial plexus. Single chromaffin cells are found seldom within the nervous plexus.The paraganglia are thought to have an endocrine function.

     

A comparison between histochemically demonstrable Golgi-associated and bile canalicular TDP-ase activity in liver

Summary Histochemically demonstrable Golgi-associated TDP-ase activity in liver cells from cat, chicken, rat and frog has been investigated.This activity is highly substrate-specific, insensitive to aldehyde fixation, ethanol, acetate, lead and most enzyme inhibitors. It is stimulated by divalent manganese, calcium, magnesium and cobalt and optimum pH is at pH 6 to 7.The characteristics are identical for all four species but significant differences exist at a comparison with bile canalicular activity, Golgi-associated activity in other cells and biochemical findings.This study was supported in part by a grant from the Swedish Medical Research Council.     

Comparative studies on the regulation of DAHP synthetase activity in blue-green and green algae

Summary Regulation of DAHP synthetase activity was investigated in autotrophically grown blue-green and green algae. Members of the class of blue-green algae possess an enzyme, the activity of which is regulated by l-tyrosine and l-phenylalanine, whereby l-tyrosine is effective in 100 fold lower concentrations. DAHP synthetases of two organisms, Anabaena and Anacystis, were shown to belong to the V-type of allosteric enzymes.In contrast to the DAHP synthetase of blue-green algae regulation of this enzyme could not be demonstrated in two green algae, Ankistrodesmus and Maesotaenium. However, Euglena gracilis, both under conditions of mixotrophic and autotrophic growth, exhibits very effective regulation of this key enzyme; again, the inhibitors are tyrosine and phenylalanine. DAHP synthetase activity of Euglena has been purified about 40 fold; during this enrichment no separation of the enzyme activity inhibited by tyrosine and that by phenylalanine could be observed.     

Kritische Bemerkungen zuPapaver bracteatum Lindl.

Zusammenfassung Form und Behaarung des Kelches und die Farbe der Kronblätter werden als wichtigste diagnostische Merkmale vonPapaver bracteatum Lindl. beschrieben. Sie erlauben dessen eindeutige Unterscheidung von verwandten Taxa. Dagegen sind die Brakteen, denen in der Literatur große Aufmerksamkeit geschenkt wird, für eine Trennung ungeeignet.

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Summary Shape and pubescence of calyx and colour of petals are described as important diagnostic characters ofPapaver bracteatum Lindl. They allow a correct separation from related taxa. In contrast to the view found in literature the bracts are not essential to discrimination.

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Wir danken Herrn Prof. Dr. K.Mothes herzlich für sein Interesse am Fortgang unserer Untersuchungen und Herrn Dr. K.Werner vom Institut für Systematische Botanik und Pflanzengeographie der Universität Halle für kritische Diskussionen bei der Abfassung des Manuskriptes.     

Der Einfluss von Gebirge und See auf die 17-Ketosteroidausscheidung im Harn

Zusammenfassung Bei 11 Studenten aus Mainz wurde im September 1964 in Oberstdorf/Allgäu (843 m) und im September 1965 auf der Nordseeinsel Norderney täglich die Ausscheidung der 17-Ketosteroide untersucht, um den Adaptationsverlauf zu prüfen. Alle Versuchspersonen hatten eine erhöhte 17-KS-Ausscheidung,die an der Nordsee höher war als im Gebirge. Der Höhepunkt der Ausscheidung lag um den 10. Tag. Es bestanden individuelle Unterschiede in der 17-KS-Ausscheidung. Je niedriger diese vorher war, desto höher war die relative Steigerung im Gebirge und an der See.Während der Beobachtungsperiode waren wetterbedingte Abweichungen von den periodischen Schwankungen nachweisbar.

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The 17-ketosteroid excretion of 11 students from the University of Mainz was investigated during September 1964 in Oberstdorf (843 m) and in September 1965 on the North Sea island Norderney. All subjects had an increased 17-ketosteroid excretion which was higher at the sea than in the mountains.The maximum of the values was around the 10th day. There were individual differences; the lower the excretion at Mainz the higher was the relative increase at both locations. During the observation period deviations from the periodic changes were observed which were due to the effect of weather.

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Resume Afin d'examiner l'adaptation de 11 étudiants au milieu,on a analysé chaque jour leur excrétion de 17-kétostéroïde. Ces essais ont eu lieu en septembre 1964 à Oberstdorf/Allgäu (843 m d'altitude) et en septembre 1965 sur lïle de Norderney dans la Mer du Nord. On a pu déceler une augmentation de 17-kétostéroïde chez toutes les personnes examinées. Cette augmentation fut toutefois plus marquée au bord de la mer qu'en montagne. L'excrétion en fut maximum le 10ème jour.On a remarqué en outre des différences individuelle. Plus l'excrétion était faible au départ et plus l'augmentation relative était marquée ausi bien au bord de la mer qu'en montagne.Pendant la période des examens, on a pu prouver des divergences météorotropiques par rapport aux fluctuations périodiques.