Life Sciences and Chemistry

Skeletal muscle has a remarkable capacity to regenerate following exercise or injury and harbors two different types of adult stem cells to accomplish the job: satellite cells and adult stem cells that can be isolated as side population (SP) cells. A certain group of these stem cells is involved in muscle tissue repair, but is only triggered into the muscle cell development pathway by injury. The question then arises: what molecular factors turn these adult stem cells into muscle cells? Now Michael

Among the model systems for studying development, the zebrafish has become prized because its transparent embryo develops outside the mother’s body. The zebrafish has helped biologists identify many genes involved in embryogenesis and, because it’s a vertebrate animal, has become a valuable resource for identifying genes involved in human disease. Zebrafish are the focus of two research articles and an accompanying news feature in this issue of PLoS Biology.

Thomas Bartman and colleagues us

In an article published in the May 2004 issue of The American Naturalist, Wilte G. Zijlstra (University of Leiden), Marc J. Steigenga (University of Leiden), P. Bernhardt Koch (University of Erlangen), Bas Zwaan (University of Leiden), and Paul M. Brakefield (University of Leiden) explore the relationship between hormones and environmental adaptation in butterflies.

Hormones are crucial for the development of organisms. In the tropical butterfly, Bicyclus anynana, ecdysone affects eyespot si

Contrary to what some scientists have suggested, key intracellular particles known as ribosomes serve as mechanical matchmakers or readout devices rather than acting chemically to speed up reactions in the body the way enzymes do, University of North Carolina at Chapel Hill researchers and colleagues have discovered.

A report on the findings by Drs. Annette Sievers and Richard Wolfenden of the UNC School of Medicine appears in the new issue of the Proceedings of the National Academy of Scien

In an unusual but useful example of cellular flip-flop, a new research study demonstrates that multiple cell types have the ability to temporarily switch into renin-secreting cells when they are needed to stabilize blood pressure. The research, published in the May issue of Developmental Cell, demonstrates that the recruited cells are direct descendants of cells that expressed renin at one time during development.

Renin is a hormone released into the blood by specialized cells in the walls

Viagra affects growth of the male sex organ of plants, by intensifying the effect of nitric oxide during plant fertilization. This discovery, made by the Plant Development team at the Instituto Gulbenkian de Ciência (IGC), in Portugal, will be published in Development, in June. The study, led by José Feijó, takes a step further in understanding fertilization in plants, a complex process but an absolutely essential one for the survival and evolution of species.

Pollen grains, which contain t