Cumulative record of motor activity. (A new procedure and its use for the study of central stimulant drugs)

Zusammenfassung Eine Methode zur kumulativen Registrierung spontaner motorischer Aktivität kleiner Tiere wird beschrieben. Die Wirksamkeitsbestimmung aus dem kumulativen Rekord und die analytische Bedeutung der Methode für die Wirkungsweise zentralstimulierender Substanzen wird diskutiert.     

Prevalence of ras gene mutations in human colorectal cancers

A combination of DNA hybridization analyses and tissue sectioning techniques demonstrate that ras gene mutations occur in over a third of human colorectal cancers, that most of the mutations are at codon 12 of the c-Ki-ras gene and that the mutations usually precede the development of malignancy.     

The effect of radioprotective chemicals on phosphorescent emission of riboflavine in oxygenated and deoxygenated solutions

Zusammenfassung Einige Strahlenschutzsubstanzen und chemisch verwandte Verbindungen wurden in ihrer Wirkung bzw. Veränderung der Wellenlänge, die durch phosphoreszierendes Licht von Riboflavin-, Rhodamin-und Akridinlösungen auftrat, untersucht. Es wurde gefunden, dass nur die Strahlenschutzsubstanzen optisch aktiv waren.     

Glutamate synthase: a fascinating pathway from L-glutamine to L-glutamate

Glutamate synthase is a multicomponent iron-sulfur flavoprotein belonging to the class of N-terminal nucleophile amidotransferases. It catalyzes the conversion of L-glutamine and 2-oxoglutarate into two molecules of L-glutamate. In recent years the X-ray structures of the ferredoxin-dependent glutamate synthase and of the a subunit of the NADPH-dependent glutamate synthase have become available. Thanks to X-ray crystallography, it is now known that the ammonia reaction intermediate is transferred via an intramolecular tunnel from the amidotransferase domain to the synthase domain over a distance of about 32Å. Although ammonia channeling is a recurrent theme for N-terminal nucleophile and triad-type amidotransferases, the molecular mechanisms of ammonia transfer and its control are different for each known amidotransferase. This review focuses on the intriguing mechanism of action and self-regulation of glutamate synthase with a special focus on the structural data.Received 8 August 2003; received after revision 15 September 2003; accepted 17 September 2003     

Living arrangements among older people: an overview of trends in Europe and the USA

This article compares the trends in living arrangements of older people in several European countries and in the United States. Trends and cross-country variability in several factors that could account for these cross-national differences, including marital status, fertility, labour force participation and attitudes, are also examined. In most countries the proportion of older people living alone increased substantially between 1970 and 1990. However the increase in living alone stabilised or even declined between 1990 and 2000 in most of the countries analysed indicating a possible reversal in the trend. Increases in proportions of older women who are married and reductions in the proportions childless may partially explain this. Considerable variability in both trends and levels of older people's living arrangements was seen especially between north-western and southern European countries. These variations mirrored contrasts in attitudes towards residential care and parent-child coresidence between the countries.     

An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20

Soft gamma-ray repeaters (SGRs) are 'magnetars', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B approximately 10(15) gauss (refs 1 , 2 -3). On 27 December 2004, a giant flare was detected from the magnetar SGR 1806-20 (ref. 2), only the third such event recorded. This burst of energy was detected by a variety of instruments and even caused an ionospheric disturbance in the Earth's upper atmosphere that was recorded around the globe. Here we report the detection of a fading radio afterglow produced by this outburst, with a luminosity 500 times larger than the only other detection of a similar source. From day 6 to day 19 after the flare from SGR 1806-20, a resolved, linearly polarized, radio nebula was seen, expanding at approximately a quarter of the speed of light. To create this nebula, at least 4 x 10(43) ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles.     

The Rae1-Nup98 complex prevents aneuploidy by inhibiting securin degradation

Cdc20 and Cdh1 are the activating subunits of the anaphase-promoting complex (APC), an E3 ubiquitin ligase that drives cells into anaphase by inducing degradation of cyclin B and the anaphase inhibitor securin. To prevent chromosome missegregation, APC activity directed against these mitotic regulators must be inhibited until all chromosomes are properly attached to the mitotic spindle. Here we show that in mitosis timely destruction of securin by APC is regulated by the nucleocytoplasmic transport factors Rae1 and Nup98. We show that combined Rae1 and Nup98 haploinsufficiency in mice results in premature separation of sister chromatids, severe aneuploidy and untimely degradation of securin. We find that Rae1 and Nup98 form a complex with Cdh1-activated APC (APC(Cdh1)) in early mitosis and specifically inhibit APC(Cdh1)-mediated ubiquitination of securin. Dissociation of Rae1 and Nup98 from APC(Cdh1) coincides with the release of the mitotic checkpoint protein BubR1 from Cdc20-activated APC (APC(Cdc20)) at the metaphase to anaphase transition. Together, our results suggest that Rae1 and Nup98 are temporal regulators of APC(Cdh1) that maintain euploidy by preventing unscheduled degradation of securin.