Über die Fettsäuren aus Spinatchloroplasten

Summary The fatty acids of two samples of chloroplasts fromSpinacia oleracea have been investigated quantitatively. They contain many polyenoic fatty acids (more than 70% of the total fatty acids); amongst these, a relatively high content of C¹⁶-trienoic acid is remarkable. Moreover, the presence of the ³-trans-hexadecenoic acid, recently detected in plants, is noteworthy.     

Outline of a cybernetic working hypothesis of cochlea based on experiments

Zusammenfassung Basierend auf eingehenden Versuchs- und Messreihen am Hörorgan des Wasserbüffels (Anoa bubalis), dessen Innenohr dem menschlichen nahezu gleicht, wird ein kybernetisches Modell des Hörinstruments geschildert, das eine einfache und widerspruchslose Erklärung der Eigenschaften des Ohres gestattet.     

Zur Wirkung von Strahlenschutzstoffen an Thymuszellen

Summary Lymphocytes of the thymus can be protected against early pycnotic degeneration by several SH-compounds. Protective and non-protective SH-compounds induce the same reaction in the non-irradiated mouse, weight loss caused by cell migration, stimulation of the reticulum. A direct relationship between the activity of the reticulum and the radioresistance of lymphocytes was not found.     

Phylogenomic analyses unravel annelid evolution

Annelida, the ringed worms, is a highly diverse animal phylum that includes more than 15,000 described species and constitutes the dominant benthic macrofauna from the intertidal zone down to the deep sea. A robust annelid phylogeny would shape our understanding of animal body-plan evolution and shed light on the bilaterian ground pattern. Traditionally, Annelida has been split into two major groups: Clitellata (earthworms and leeches) and polychaetes (bristle worms), but recent evidence suggests that other taxa that were once considered to be separate phyla (Sipuncula, Echiura and Siboglinidae (also known as Pogonophora)) should be included in Annelida. However, the deep-level evolutionary relationships of Annelida are still poorly understood, and a robust reconstruction of annelid evolutionary history is needed. Here we show that phylogenomic analyses of 34 annelid taxa, using 47,953 amino acid positions, recovered a well-supported phylogeny with strong support for major splits. Our results recover chaetopterids, myzostomids and sipunculids in the basal part of the tree, although the position of Myzostomida remains uncertain owing to its long branch. The remaining taxa are split into two clades: Errantia (which includes the model annelid Platynereis), and Sedentaria (which includes Clitellata). Ancestral character trait reconstructions indicate that these clades show adaptation to either an errant or a sedentary lifestyle, with alteration of accompanying morphological traits such as peristaltic movement, parapodia and sensory perception. Finally, life history characters in Annelida seem to be phylogenetically informative.     

Über die Wirkung von Phenanthrenchinon (9, 10) und einer wasserlöslichen Transportform auf Glykolyse und Atmung des Ascites-Tumor

Summary Phenanthrenchinon (9, 10) and hydrochinon-bis-glycylester prepared as water-soluble transportform, are strong inhibitors of glycolysis. Glycolysing cells are depleted from ATP in a few minutes.     

α-Tocopherol reduces fluorescent age pigment levels in heart and brain of young mice

Summary The levels of fluorometrically measured lipofuscin, or age pigment, were significantly lower in the brain and the heart of -tocopherol (vitamin E)-injected mice as compared to untreated control mice at 3 and at 5 months of age.     

North Pacific seasonality and the glaciation of North America 2.7 million years ago

In the context of gradual Cenozoic cooling, the timing of the onset of significant Northern Hemisphere glaciation 2.7 million years ago is consistent with Milankovitch's orbital theory, which posited that ice sheets grow when polar summertime insolation and temperature are low. However, the role of moisture supply in the initiation of large Northern Hemisphere ice sheets has remained unclear. The subarctic Pacific Ocean represents a significant source of water vapour to boreal North America, but it has been largely overlooked in efforts to explain Northern Hemisphere glaciation. Here we present alkenone unsaturation ratios and diatom oxygen isotope ratios from a sediment core in the western subarctic Pacific Ocean, indicating that 2.7 million years ago late-summer sea surface temperatures in this ocean region rose in response to an increase in stratification. At the same time, winter sea surface temperatures cooled, winter floating ice became more abundant and global climate descended into glacial conditions. We suggest that the observed summer warming extended into the autumn, providing water vapour to northern North America, where it precipitated and accumulated as snow, and thus allowed the initiation of Northern Hemisphere glaciation.