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Jorge E. Galán is an Argentinian physician engaged in researching the molecular mechanisms of bacterial infections. His work has concentrated on Salmonella enterica ssp. and Campylobacter jejuni. His findings concerning the interactions between bacteria and their host cells have provided the basis for the development of new medicines and vaccines.
Galán began his scientific career as a veterinarian. He concerned himself early on with infectious diseases, at first mainly with those in horses. His interest in salmonella arose during his postdoc studies at Washington University in St. Louis. These rod-shaped bacteria, which are the most common cause of diarrhoea resulting from food poisoning, invade the epithelial cells of the small intestine´s mucous membrane in order to eventually migrate into the tissue beneath it. Many central questions, however, remained unanswered. How is that microorganism able to gain entry into the host cell? How does it succeed in evading the immune system´s defences? Why is salmonella only able to cause life-threatening typhoid fever in humans but not in other mammals?
Upon closer inspection, Galán realized that a bacterium manipulates its host cell in a very complex and simultaneously elegant way in order to instrumentalize it for its own purposes. His proof that salmonella – much like other bacteria – uses the Type III secretion system, a kind of molecular "shot”, in order to infiltrate host-cells, has proven to be of fundamental significance. Great attention has been given to Galepidermal growth factor receptor on the surface of the small intestine´s cells as the “door opener”. The bacteria are able to gain control of the receptor by attaching to a suitable molecule without causing the host-cell to be destroyed. In order to avoid destruction by macrophages, the bacteria immediately activate a protein that alters the lipid composition of the vacuoles within which they have been enveloped.
Apparently the salmonella bacteria have acquired intimate knowledge about their host-cells in the course of millions of years. Galán was constantly fascinated by the enormity of this adaptation process. The proteins necessary for the invasion of the host-cell were put into position on a kind of “sorting platform” so that their services could be called upon at any time – as our researcher was able to demonstrate. According to Galán, a difference in one single oxygen atom in the receptor for the toxin of „Salmonella typhi“ accounted for the fact that only people are afflicted with life-threatening typhoid fever while other mammals are not. The multidisciplinary application of genetic, immunological, and cellular and structural biological methods provided him insights into the fundamental biological functions of cells.
Galán places great importance on doing research that will lead to improvements in public health. His findings regarding the interaction between salmonella and its host-cell provided different initiating steps for the development of novel medicines against which these bacteria will possibly find it much more difficult to develop resistances like they are able to do against conventional antibiotics. For a number of years, Galan’s Yale University lab has employed the same meticulousness that was applied to salmonella to examining infections caused by Campylobacter jejuni, the danger of which has become more and more of a public concern. He has sustained his commitment to supporting young scientists in his area of expertise by establishing a predoctoral Training Program in Microbial Pathogenesis.
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