Chemotaxonomy of Anseriformes

The composition of the uropygial gland wax of 8 species of birds of the order Anseriformes was investigated. As was expected, the waxes are composed of more or less methyl-branched fatty acids and alcohols. The results obtained have been compared with those on other species of Anseriformes and discussed from a chemotaxonomical viewpoint. For this purpose the various parameters have been depicted on a 3-dimensional matrix.     

A Positive Feedback between Growth and Polarity Provides Directional Persistency and Flexibility to the Process of Tip Growth

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Heat challenges can enhance population tolerance to thermal stress in mussels: a potential mechanism by which ship transport can increase species invasiveness

It is unclear whether transport by human vectors can increase the robustness of translocated populations and thereby enhance their invasiveness. To test this concept, we investigated the effect of heat stress on the tolerance of mussel populations towards a second stress event of the same kind. The heat challenges we mimicked can be faced by marine invertebrates that are transported through regions with high sea surface temperatures on ship hulls or in ballast water tanks. The study included 5 mussel species that were collected at sites in Brazil, Chile, Finland, Germany (Baltic Sea) and Portugal. In parallel laboratory experiments, monospecific groups of individuals were exposed to heat challenges that caused 60–83% mortality in the experimental groups within 15–28 days. The surviving individuals were exposed to a second stress event of the same kind, while their survival was then compared to the robustness of conspecifics that had not been exposed to elevated temperatures before. We observed that thermal tolerance was significantly enhanced by previous heat stress experience in case of Semimytilus algosus from Chile and in case of Mytilus edulis from Germany. Our results suggest that heat challenges, which marine invertebrates experience during transport, can enhance stress tolerance in founder populations of these species in their non-native range by potentially increasing the frequency of genetically adapted genotypes. This points at the necessity to learn more about selection acting on organisms during human-mediated transport—in the aquatic but also in the terrestrial environment.     

A Shockley‐Type Polymer: Fullerene Solar Cell

Charge extraction rate in solar cells made of blends of electron donating/accepting organic semiconductors is typically slow due to their low charge carrier mobility. This sets a limit on the active layer thickness and has hindered the industrialization of organic solar cells (OSCs). Herein, charge transport and recombination properties of an efficient polymer (NT812):fullerene blend are investigated. This system delivers power conversion efficiency of >9% even when the junction thickness is as large as 800 nm. Experimental results indicate that this material system exhibits exceptionally low bimolecular recombination constant, 800 times smaller than the diffusion‐controlled electron and hole encounter rate. Comparing theoretical results based on a recently introduced modified Shockley model for fill factor, and experiments, clarifies that charge collection is nearly ideal in these solar cells even when the thickness is several hundreds of nanometer. This is the first realization of high‐efficiency Shockley‐type organic solar cells with junction thicknesses suitable for scaling up.     

Convenient procedure for the isolation of highly enriched,cytochrome P-450-containing microsomal fraction from Candida tropicalis

The suitability of Ca²⁺ ions for the precipitation of the microsomal fraction from the hydrocarbon-grown yeast Candida tropicalis was evaluated. In the final procedure the microsomes were precipitated by the addition of 16 mm CaCl₂. Crude extracts obtained from cells via spheroplast lysis were centrifuged at 12,000g for 15 min and at 25,000g for 15 min prior to precipitation. The cytochrome P-450 content of the fraction was between 0.22 and 0.35 nmol mg^?1 protein. The isolated microsomes exhibited both hexadecane hydroxylation activity and NADPH-cytochrome c reductase activity.     

Isoenzyme pattern of malate dehydrogenase during respiratory derepression in Schizosaccharomyces pombe

One isoenzyme of malate dehydrogenase with an isoelectric point of 6.4 was found in glucose-repressed cells of Schizosaccharomyces pombe. During respiratory derepression the activity of this isoenzymes decreased rapidly in vivo. In the course of this inactivation two new forms of malate dehydrogenase with isoelectric points of 6.0 and 5.7 appeared. It has been found that these two enzymic forms disappeared 4 h after the exhaustion of glucose; probably they are degradation products of the isoenzyme present in glucose-repressed cells. Fully derepressed cell of this fission yeast contain one isoenzyme of malate dehydrogenase with an isoelectric point of 5.3. The synthesis of this isoenzyme is initiated at glucose concentrations below 1.5 g/l.     

Untersuchungen zur entwicklungsgeschichte der araneae [Pardosa Hortensis (Thorell)] unter besonderer berücksichtigung des vorderen prosomaabschnittes

Ohne ZusammenfassungDie Untersuchungen warden mit Unterstützung der Deutschen Forschungsgemeinschaft in den Jahren 1965–1966 im Zoologischen Institut der Universität Kiel durchgeführt. Herrn Prof. Dr. R. Siewing möchte ich meinen herzlichsten Dank sagen für die Überlassung des Themas, für seinen freundlichen Rat und seine stote Hilfsbereitschaft während der Durchführung meiner Untersuchungen. Herrn Dr. G. Scholl bin ich sehr verbunden für zwei mir zur Verfügung gestellte Präparate und eine Zeichnung von Carausius, und ich danke ihm ebenfalls für seine Anteilnahme am Gelingen meiner Arbeit.     

Der Nucleolus und seine Beziehungen zu den Ribosomen des Cytoplasmas. Eine Untersuchung an den Malpighischen Gefässen von Drosophila melanogaster

Summary The investigation described herein is concerned with the structure and the behavior of the nucleolus of the cells of the Malpighian tubules of Drosophila melanogaster (see Fig. 16).Primarly the nucleolus consists of ribonucleic-acid granules about 150 Å in diameter which, with electron microscope, are not distinguishable from the ribosomes of the cytoplasm; they lie on or within the structural network of the nucleolus (Fig. 9). During the stages of the life history of the insect the nucleolus shows correspondingly characteristic peculiarities in structure which reflect the varying functional stages of the cell: The structure is loose in the cells of the larva (Fig. 2) and imago (Fig. 12), whereas it is compact in the pupa (Fig. 8, 9). In pupa sufficiently mature for emergence, the nucleolus contains a large central vacuole (Fig. 8, 9). The nucleolus of the larva has a similar appearance after a decrease in assimilation induced by starvation (Fig. 10, 11).There are smaller vacuoles in the nucleolus which mostly are filled with parts of the nucleolus-chromosome. In the pupal stage some of the peripheral constituents of the nucleolus separate and move to the nuclear membrane through which they pass via pores into the cytoplasm (Fig. 3, 4).Larger pieces reach the cytoplasm by local dissolution of the nuclear membrane (Fig. 5). During this process the extruded nucleolar material is dispersed into its structural components. Because the cytoplasm becomes richer in ribosomes during the period of nucleolar extrusion (Fig. 1b), it can be assumed, that the nucleolus must be a source of ribosomes, and that through such an extrusion which has been demonstrated to be a natural process (Fig. 7) the cytoplasm can be provided with ribosomes rapidly.The importance of this phenomenon in the synthesis of imaginal body is discussed.In the nucleus there are many vacuoles with a diameter of about 425 Å (Fig. 15a, b) which pass through the pores of membrane in the cytoplasm (Fig. 15c).

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Die Untersuchung wurde mit Unterstützung der Deutschen Forschungsgemeinschaft durchgeführt.     

Über die tagesperiodische Ausdrift von Niphargus aquilex schellenbergi Karaman aus Quellen

Zusammenfassung Die Ausdrift von Niphargus aquilex schellenbergi Karaman aus Quellen verläuft tagesperiodisch. Sie wind durch eine Aufwanderung kompensiert. Drift und Aufwanderung werden als regelmäßige Bewegungen zwischen Spaltenwasser und Quellbach angesehen. Durch Farbmarkierung wird nachgewiesen, daß sie Niphargen unterhalb des Quellabflusses Nahrung aufnehmen und zurückwandern.Extrem große Driftfänge, deren Zusammensetzung sich auch qualitativ von der normalen Drift unterscheidet, können bisher noch night zufriedenstellend erklart werden.Die Tagesperiodik der Ausdrift wird von LD-Wechsel gesteuert. Schwankungen von Temperatur, O₂- und CO₂-Gehalt des Wassers lassen keinen Einfluß erkennen. Es wird vermutet, daß die Tagesperiodik der Ausdrift auf einer Aktivitätsperiodik beruht.

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Summary Amphipodes of the genus Niphargus regularly drift to the surface of springs. The number of animals drifting per 2 hr.-period, shows characteristic changes between day and night. The drift of Niphargus is not an uncontrolled passive process, but likely dependent upon locomotor activity.Dye-markings show, that the drift is compensated by upstream migrations and that Niphargus feeds in the brook before it goes back into the rock crevices.Sometimes the number of Niphargus in the drift-samples is extremly high. In this case the typical pattern of the periodicity and the average size of the amphipodes are markedly changed. This phenomenon (extreme drift) cannot yet be explained satisfactorily.The diel periodicity is timed by LD-changes. Fluctuations of temperature, O₂- and CO₂-content of the water did not produce any effect under natural conditions.