Blog – Page 2501

They reveal the origin of wine, the age of bones and fossils, and they serve as diagnostic tools in medicine. Isotopes and isotopologues—molecules that differ only in the composition of their isotopes—also play an increasingly important role in astronomy. For example, the ratio of carbon-12 (12C) to carbon-13 (13C) isotopes in the atmosphere of an exoplanet allows scientists to infer the distance at which the exoplanet orbits its central star.

Until now, 12C and 13C bound in carbon monoxide were the only isotopologues that could be measured in the atmosphere of an exoplanet. Now a team of researchers has succeeded in detecting ammonia isotopologues in the atmosphere of a cold brown dwarf.

As the team has just reported in the journal Nature, ammonia could be measured in the form of 14NH3 and 15NH3. Astrophysicists Polychronis Patapis and Adrian Glauser, who are members of the Department of Physics as well as of the National Centre of Competence in Research (NCCR) PlanetS, were involved in the study—Patapis as one of the first authors.

Major work led by Dr. André Veillette’s team at the Institut de recherches cliniques de Montréal (IRCM), in collaboration with a group of researchers, and just published in Nature Immunology, managed to identify a previously unknown molecular action that prevents phagocytosis, which is a process that promotes the immune system’s response to cancer. A Research Briefing on the work done by the team has been published in the same journal.

Macrophages are cells of the immune system. One of the roles of macrophages is to engulf, or “eat,” cells that are defective or dangerous, including cancer cells. This process is named phagocytosis. Macrophages can be called into action to eliminate cancer cells. However, this capacity is often defective, because macrophages are put in a state of dormancy by the cancer cells.

This is in part because a particular molecule called CD47 is often over-abundant on cancer cells. CD47 prevents phagocytosis by triggering a molecule or “receptor” on macrophages named SIRPα. Agents that block the ability of CD47 to trigger SIRPα have shown promising results for treating cancer.