Selective blockade by mephentermine of reserpine-induced serotonin depletion

Zusammenfassung Die kombinierte i.v. Verabreichung von Reserpin (1 mg/kg) und Mephentermin (1 mg/kg) bewirkte Erregung in Kaninchen. Diese Erregung ist verbunden mit einem Verlust an Noradrenalin (NE) im Gehirn, nicht jedoch mit einem Verlust an Serotonin (5-HT). Aus den Ergebnissen lässt sich schliessen, dass die beobachtete Erregung von einem momentanen Ungleichgewicht zwischen NE und 5-HT im Gehirn herrührt.

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This study is supported in part by Career Development Award No. K3 NB 15279-09 and Grant No. MH 11189 from the National Institutes of Health, U.S.P.H.S. The authors wish to thank Dr.A. J. Plummer of CIBA Pharmaceutical Company for supplying the reserpine phosphate and Dr.R. J. Bower of Wyeth Laboratories for the mephentermine used in this study.     

Structure of co-crystals of tropomyosin and troponin

Troponin, a Ca2+-sensitive complex, regulates the motions of tropomyosin on the thin filaments in many muscles. It has three subunits, each with a different architecture and function: TnC binds Ca2+; TnI binds to actin and inhibits contraction; and TnT binds one complex to each tropomyosin molecule. The troponin complex has an elongated shape with TnC and TnI forming a globular 'head' region and TnT a long (approximately 160 A) 'tail'. TnT binds to two widely separated regions of tropomyosin: the head region of the complex is near Cys 190 of tropomyosin and the tail region is near the overlapping joint that links the tropomyosin molecules into filaments. Here we report the X-ray structure determination at 17 A resolution of glutaraldehyde-treated tropomyosin crystals in which native troponin complex or fragments of TnT have been bound. Our results show that the amino-terminal tail end of TnT spans the head-to-tail joint of the tropomyosin filaments, and that the 'head' region of the whole troponin complex binds approximately 200 A away near residues 150-180 of the tropomyosin molecule.     

Pleistocene Homo sapiens from Middle Awash,Ethiopia

The origin of anatomically modern Homo sapiens and the fate of Neanderthals have been fundamental questions in human evolutionary studies for over a century. A key barrier to the resolution of these questions has been the lack of substantial and accurately dated African hominid fossils from between 100,000 and 300,000 years ago. Here we describe fossilized hominid crania from Herto, Middle Awash, Ethiopia, that fill this gap and provide crucial evidence on the location, timing and contextual circumstances of the emergence of Homo sapiens. Radioisotopically dated to between 160,000 and 154,000 years ago, these new fossils predate classic Neanderthals and lack their derived features. The Herto hominids are morphologically and chronologically intermediate between archaic African fossils and later anatomically modern Late Pleistocene humans. They therefore represent the probable immediate ancestors of anatomically modern humans. Their anatomy and antiquity constitute strong evidence of modern-human emergence in Africa.     

Catastrophic ape decline in western equatorial Africa

Because rapidly expanding human populations have devastated gorilla (Gorilla gorilla) and common chimpanzee (Pan troglodytes) habitats in East and West Africa, the relatively intact forests of western equatorial Africa have been viewed as the last stronghold of African apes. Gabon and the Republic of Congo alone are thought to hold roughly 80% of the world's gorillas and most of the common chimpanzees. Here we present survey results conservatively indicating that ape populations in Gabon declined by more than half between 1983 and 2000. The primary cause of the decline in ape numbers during this period was commercial hunting, facilitated by the rapid expansion of mechanized logging. Furthermore, Ebola haemorrhagic fever is currently spreading through ape populations in Gabon and Congo and now rivals hunting as a threat to apes. Gorillas and common chimpanzees should be elevated immediately to 'critically endangered' status. Without aggressive investments in law enforcement, protected area management and Ebola prevention, the next decade will see our closest relatives pushed to the brink of extinction.