Environmental filtering -- not a host of other theories -- determines local plant diversity in one of Earth's biodiversity hotspots according to an article in the Sept. 26 edition of Science by Smithsonian Tropical Research Institute scientist Benjamin Turner and colleagues from the University of Western Australia.

In a collaborative study, researchers from the Brazilian Biosciences National Laboratory at the Brazilian Center for Research in Energy and Materials, the University of California in San Diego and the Technische Universität München identified a new mechanism to inhibit proteasomes, protein complexes that are a target for cancer therapy.

Researchers from the University of Sao Paulo have identified an RNA known as INXS that modulates the action of an important gene in the process of programmed cell death. In experiments on mice, they were able to effect a 10-fold reduction in the volume of subcutaneous malignant tumors. The findings were published in the most recent issue of the journal Nucleic Acids Research.

A 2°C increase in temperature around the world by 2050, according to one of the scenarios predicted by the Intergovernmental Panel on Climate Change, may be advantageous to the physiology and the biochemical and biophysical processes involved in the growth of forage plants such as Stylosanthes capitata Vogel, a legume utilized for livestock grazing in tropical countries such as Brazil.

The demonstration that astrocytes, the brain's most abundant cell type, participate in the formation of inhibitory synapses in the cortex suggests an important role for these cells in some neurological disorders.

A study conducted by scientists in Brazil and the United Kingdom has quantified the impact that selective logging, partial destruction by burning, and fragmentation resulting from the development of pastures and plantations have had on the Amazon rainforest. In combination, these factors could be removing nearly 54 million tons of carbon from the forest each year, introduced into the atmosphere as greenhouse gases. This total represents up to 40 percent of the carbon loss caused by deforestation in the region.

The reduction of soil carbon stock caused by the conversion of pasture areas into sugarcane plantations may be offset within two or three years of cultivation. The calculation appears in a study conducted by researchers at University of Sao Paulo in collaboration with colleagues from the Federal Institute of Alagoas, the Brazilian Bioethanol Science and Technology Laboratory, the Institut de Recherche pour le Developpement in France and Harvard University, Colorado State University and the Shell Technology Center Houston in USA.

Brazilian researchers have confirmed the importance of a specific group of neurons found in a region of the brain known as the retrotrapezoid nucleus (RTN) in detecting changes in carbon dioxide (CO2) levels and in modulating the activity of the neuronal groups that control respiratory activity. The group's work has demonstrated that the respiratory changes caused by the increase in CO2 levels are compromised during the occurrence of selective destruction of the RTN neurons that express Phox2b.