From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways

The human body hosts an enormous abundance and diversity of microbes, which perform a range of essential and beneficial functions. Our appreciation of the importance of these microbial communities to many aspects of human physiology has grown dramatically in recent years. We know, for example, that animals raised in a germ-free environment exhibit substantially altered immune and metabolic function, while the disruption of commensal microbiota in humans is associated with the development of a growing number of diseases. Evidence is now emerging that, through interactions with the gut-brain axis, the bidirectional communication system between the central nervous system and the gastrointestinal tract, the gut microbiome can also influence neural development, cognition and behaviour, with recent evidence that changes in behaviour alter gut microbiota composition, while modifications of the microbiome can induce depressive-like behaviours. Although an association between enteropathy and certain psychiatric conditions has long been recognized, it now appears that gut microbes represent direct mediators of psychopathology. Here, we examine roles of gut microbiome in shaping brain development and neurological function, and the mechanisms by which it can contribute to mental illness. Further, we discuss how the insight provided by this new and exciting field of research can inform care and provide a basis for the design of novel, microbiota-targeted, therapies.GB Rogers, DJ Keating, RL Young, M-L Wong, J Licinio, and S Wesseling

State predation in historical perspective: the case of Ottoman müsadere practice during 1695–1839

International audienceThis paper studies the practice of Müsadere in the Ottoman Empire. Müsadere refers to the expropriation of elites—often tax farmers or administrators—by the Sultan. This practice is interesting from both political economy and economic history perspectives as the Ottoman Empire continued to increase its reliance on it during the eighteenth century, a period when European states were investing in fiscal capacity and building bureaucratic tax systems. The main argument is that Sultans faced a “political Laffer curve:” if revenue is too low, the state collapses; if fiscal extraction is too high there is a rebellion and the Sultan risks losing power. While expropriations (müsadere) allow the Sultan to keep taxes low, they are vulnerable to provoking elites to invest in fugitive rather than (more productive) captive assets. We also show that the Sultan is more prone to target politically strong elites when his fiscal capacity is low