Synthesis of L-[3-2H,18O]glycerol and its incorporation into the 4-methyl-5-hydroxyethyl thiazole moiety of thiamine byEscherichia coli

Summary L-[3-²H,¹⁸O]glycerol was prepared and fed toEscherichia coli in order to determine the origin of the oxygen atom in the biosynthesized thiazole moiety of thiamine. Measurement by GC-MS of the isotope incorporation into the thiazole from this substrate confirmed that the 2 hydrogens and the oxygen on the C-3 carbon of glycerol are incorporated directly into the thiazole.     

The biogenesis of helminthosporal

Zusammenfassung Die Biogenese des Pilzstoffes Helminthosporal wurde untersucht, indem der Pilz bei Anwesenheit von Mevalonsäure, mit C₂ mit Kohlenstoff-14 markiert, gezüchtet wurde. Es wird gezeigt, dass das Dialdehyd aus einem tricyclischen Vorläufer durch oxidative Spaltung entsteht.     

Lysozyme activity in the plaice (Pleuronectes platessa L.)

Zusammenfassung Die Untersuchung der Lysozymverteilung im Gewebe des Knochenfischs,Pleuronectes platessa L., ergab, dass das Plasma-Lysozym von Leukozyten abstammt, das Hautschleim-Lysozym dagegen von spezifischen Epidermiszellen.     

Further geological and palaeoanthropological investigations at the Maludong hominin site, Yunnan Province, Southwest China

Three-dimensional mapping and section work undertaken by us in 2008 have identified 11 stratigraphic units at Maludong site. AMS radiocarbon dating of charcoal established an accurate and internally consistent age profile for the sequence of 17.8±0.2 ka to 13.2±0.1 ka. Archaeomagnetic analysis showed changes in externally derived pedogenically enhanced material consistent with a warming in climate between the cold period of Henrich Event 1 and the Blling-AllerCd interstadial. Human remains recovered during the 1989 excavation were derived from a deposit dating to this interstadial, or between 14.3±0.3 ka and 13.5±0.1 ka. An- thropogenic features, including burnt rocks, baked sediment and thick charcoal and ash layers, were identified and examined through archaeomagnetic analysis. Two monkey fossils are described here, one of them being reassigned from Macaca robustus to M. aft＇. M. assamensis. They confirm the young age of the site and also show signs of anthropogenic alteration in the form of burning. Additional human cranial remains are reported for the first time and new data are provided for some specimens described previously. A range of new features is identified that strengthen the affinities of the Maludong remains to archaic humans. The presence of this globally unique mosaic of archaic and modern features raises important questions about human evolutionary his- tory in East Asia during the Late Upper Pleistocene.     

The contribution of sensory experience to the maturation of orientation selectivity in ferret visual cortex.

Sensory experience begins when neural circuits in the cerebral cortex are still immature; however, the contribution of experience to cortical maturation remains unclear. In the visual cortex, the selectivity of neurons for oriented stimuli at the time of eye opening is poor and increases dramatically after the onset of visual experience. Here we investigate whether visual experience has a significant role in the maturation of orientation selectivity and underlying cortical circuits using two forms of deprivation: dark rearing, which completely eliminates experience, and binocular lid suture, which alters the pattern of sensory driven activity. Orientation maps were present in dark-reared ferrets, but fully mature levels of tuning were never attained. In contrast, only rudimentary levels of orientation selectivity were observed in lid-sutured ferrets. Despite these differences, horizontal connections in both groups were less extensive and less clustered than normal, suggesting that long-range cortical processing is not essential for the expression of orientation selectivity, but may be needed for the full maturation of tuning. Thus, experience is beneficial or highly detrimental to cortical maturation, depending on the pattern of sensory driven activity.