An estimated one-third of people around the world are infected by the parasite Toxoplasma gondii, a distant relative of the malaria parasite, although normally only persons with a weakened immune response show any symptoms. But how does T. gondii subvert immune defenses, enabling it to survive inside cells of its bird and mammal hosts? With new methods for the real-time imaging of single cells, David Holowka and his team from Cornell University, USA, obtained results that help to explain this trick: when T. gondii is about to enter a host cell, it releases a factor that dampens a key signal within the host's white blood cells, namely the release of calcium from within-cell stores into the cytoplasm, necessary to relay the message that an invader has been detected outside the cell. Holowka and colleagues suggest that T. gondii could use the same mechanism to suppress other immune responses, for example the production of cytokines, signaling molecules that promote inflammation.
Dr. David Holowka
Department of Chemistry and Chemical Biology
Cornell University, USA
Frontiers in Plant Science
Plant growth in Arabidopsis is assisted by compost soil-derived microbial communities
Plant growth has been doubled by adding soil microbes. Plants and soil microbes are constantly interacting in natural and agricultural environments and many examples of one-to-one interactions have been studied. However, the effect of mixed microbial populations on the growth and gene expression of plants still remained largely unknown. This study evaluated the growth of leaves and root
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