Single origin of Malagasy Carnivora from an African ancestor

The Carnivora are one of only four orders of terrestrial mammals living in Madagascar today. All four (carnivorans, primates, rodents and lipotyphlan insectivores) are placental mammals with limited means for dispersal, yet they occur on a large island that has been surrounded by a formidable oceanic barrier for at least 88 million years, predating the age of origin for any of these groups. Even so, as many as four colonizations of Madagascar have been proposed for the Carnivora alone. The mystery of the island's mammalian origins is confounded by its poor Tertiary fossil record, which leaves us with no direct means for estimating dates of initial diversification. Here we use a multi-gene phylogenetic analysis to show that Malagasy carnivorans are monophyletic and thus the product of a single colonization of Madagascar by an African ancestor. Furthermore, a bayesian analysis of divergence ages for Malagasy carnivorans and lemuriforms indicates that their respective colonizations were temporally separated by tens of millions of years. We therefore conclude that a single event, such as vicariance or common dispersal, cannot explain the presence of both groups in Madagascar.     

Book Reviews: Behavior Change in the Human Services: An Introduction to Principles and Applications by Martin Sundel and Sandra S. Sundel. Exploring Personality: An Intellectual Odyssey by Russell L. Ackoff. The Ecologist: The Cosmic Covenant.

Systemic Practice and Action Research -     

Thiarubrine A, a bioactive constituent of Aspilia (Asteraceae) consumed by wild chimpanzees

Two African species of Aspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals.     

Protein turnover in glycine-C14-labelled Landschütz ascites tumor cells

Zusammenfassung Untersuchungen über die Stabilität der Eiweißstoffe von Landschütz-Aszites-Tumoren wurden an C¹⁴-Glykokoll,-Valin oder -Leucin markierten Zellen durchgeführt. Es wurde festgestellt, dass während der Zellteilung und des Wachstums kontinuierlich etwa 5–10% pro Tag der einmal gebundenen C¹⁴-Aktivität als niedrigmolekulare Komponenten in die Aszitesflüssigkeit ausgeschieden wird. Diese Instabilität kommt offenbar durch intrazellulare Umsetzung der Eiweißstoffe und nicht durch Ausscheidung ganzer Eiweissmoleküle zustande.     

BOOK REVIEWS: Partnership and Participation by Ann Taket and Leroy White. Sustainable Development: Economics and Policy by P. K. Rao.

Systemic Practice and Action Research -     

Mice in the world of stem cell biology

The ability of embryos to diversify and of some adult tissues to regenerate throughout life is directly attributable to stem cells. These cells have the capacity to self-renew-that is, to divide and to create additional stem cells-and to differentiate along a specific lineage. The differentiation of pluripotent embryonic stem cells along specific cell lineages has been used to understand the molecular mechanisms involved in tissue development. The often endless capacity of embryonic stem cells to generate differentiated cell types positions the field of stem cells at the nexus between developmental biologists, who are fascinated by the properties of these cells, and clinicians, who are excited about the prospects of bringing stem cells from bench to bedside to treat degenerative disorders and injuries for which there are currently no cures. Here we highlight the importance of mice in stem cell biology and in bringing the world one step closer to seeing these cells brought to fruition in modern medicine.     

Thiarubrine A,a bioactive constituent ofAspilia (Asteraceae) consumed by wild chimpanzees

Summary Two African species ofAspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals.     

Late survival of Neanderthals at the southernmost extreme of Europe

The late survival of archaic hominin populations and their long contemporaneity with modern humans is now clear for southeast Asia. In Europe the extinction of the Neanderthals, firmly associated with Mousterian technology, has received much attention, and evidence of their survival after 35 kyr bp has recently been put in doubt. Here we present data, based on a high-resolution record of human occupation from Gorham's Cave, Gibraltar, that establish the survival of a population of Neanderthals to 28 kyr bp. These Neanderthals survived in the southernmost point of Europe, within a particular physiographic context, and are the last currently recorded anywhere. Our results show that the Neanderthals survived in isolated refuges well after the arrival of modern humans in Europe.     

56K fibroblast protein not specific for Duchenne muscular dystrophy but for skin biopsy site

Recently, we reported the detection by two-dimensional gel electrophoresis of a 56,000 (56K)-molecular weight polypeptide that was present in cultured skin fibroblasts from normal males but was not detectable in fibroblasts from Duchenne muscular dystrophy (DMD) patients. Since then we have established that the 56K polypeptide is not present in skin fibroblasts from normal females, DMD carrier females, or in normal male fibroblasts obtained from sources other than the Repository for Mutant Human Cell Strains, Montreal. Further inquiry has led to the discovery that all the normal male fibroblast cultures obtained from the Montreal repository had been established from preputial skin. Fibroblast cultures from DMD patients, DMD carriers, as well as other normal individuals, had been derived from non-genital skin biopsies. Thus, the absence of the 56K polypeptide is not specific for DMD, but rather is related to the site of skin biopsy.