Jean-Marc Reyrat (29/04/1967–28/10/2009)

Microbiologists everywhere are saddened by the recent loss of Jean-Marc Reyrat, one of their most valued colleagues, who died after a short but brave battle against cancer. Qualities that come to mind when one remembers Jean-Marc are enthusiasm, strong motivation for scientific research, original thinking, critical assessment of his own work, integrity, fairness, loyalty and dedication to young scientists. Jean-Marc fell in love with bugs in the early 1990s while studying Microbiology in Toulouse University, where he made his first steps in research in Pierre Boistard’s lab. There, Jean-Marc dissected out regulatory mechanisms of nitrogen fixation by the symbiotic bacterium Rhizobium meliloti (Reyrat et al., 1993; 1994). His love for bacteria broadened thereafter to include many different types. After completing his PhD in 1993, Jean-Marc went for a long trip in the Middle-East (back-packing was one of his passions) before joined Brigitte Gicquel’s group at the Institut Pasteur in Paris to work on one of the major infectious agents affecting mankind, Mycobacterium tuberculosis. At that time, this slow growing, GC-rich bacterium was genetically almost totally intractable, and the scientific community doubted whether it would ever be possible to create null mutants. Here, one of Jean-Marc’s characteristic traits came into play: never listen to what people say, just try yourself. Taking the urease gene of Mycobacterium bovis Bacille Camette-Guérin as a model, Jean-Marc was the first to demonstrate the feasibility of knocking out a gene in slow-growing mycobacteria (Reyrat et al., 1995). Together with Vladimir Pelicic, then a PhD student in the same laboratory, Jean-Marc decided to test the possibility of using the Bacillus subtilis sacB gene encoding levansucrase as a counter-selectable marker. They reasoned that although mycobacteria are generally referred to as Gram-positive bacteria, their complex cell wall creates an outer membrane and, hence a periplasmic-like space that could render them sensitive to accumulation of levan produced from sucrose by levansucrase in the inter-membrane compartment. This prediction was validated, and the strategy was used to create null mutants of members of the M. tuberculosis complex. This powerful genetic tool was soon put to use by many mycobacterial geneticists to improve the selection of gene-replacement events in slow-growing mycobacteria. These major breakthroughs were reported in seminal papers (Pelicic et al., 1996a,b) and opened the way for the construction of allelic exchange mutants to identify M. tuberculosis virulence determinants. Jean-Marc then decided to shift to another pathogenic bacterium, Helicobacter pylori, the major cause of stomach ulcers and strongly associated with gastric cancer. In 1996, he obtained a Marie Curie fellowship to join the renowned vaccine research centre of the Chiron Corporation – today Novartis – directed by Rino Rappuoli in Siena. He joined the team supervised by John Telford and studied the vacuolating cytotoxin, a major virulence factor encoded by the vacA gene in pathogenic H. pylori. In the 5 years that he spent in Siena, he made major contributions to the understanding of the function, cell specificity and the complex 3D structure of the VacA cytotoxin (Pagliaccia et al., 1998; Reyrat et al., 1999). Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://www3.interscience.wiley.com/ authorresources/onlineopen.html Molecular Microbiology (2010) 75(5), 1059–1060 doi:10.1111/j.1365-2958.2010.07049.x