Conservation of freshwater bivalves at the global scale: diversity, threats and research needs

Bivalves are ubiquitous members of freshwater ecosystems and responsible for important functions and services. The present paper revises freshwater bivalve diversity, conservation status and threats at the global scale and discusses future research needs and management actions. The diversity patterns are uneven across the globe with hotspots in the interior basin in the United States of America (USA), Central America, Indian subcontinent and Southeast Asia. Freshwater bivalves are affected by multiple threats that vary across the globe; however, pollution and natural system (habitat) modifications being consistently found as the most impacting. Freshwater bivalves are among the most threatened groups in the world with 40% of the species being near threatened, threatened or extinct, and among them the order Unionida is the most endangered. We suggest that global cooperation between scientists, managers, politicians and general public, and application of new technologies (new generation sequencing and remote sensing, among others) will strengthen the quality of studies on the natural history and conservation of freshwater bivalves. Finally, we introduce the articles published in this special issue of Hydrobiologia under the scope of the Second International Meeting on Biology and Conservation of Freshwater Bivalves held in 2015 in Buffalo, New York, USA.This work was supported by FCT—Foundation for Science and Technology, Project 3599—Promote the Scientific Production and Technological Development and Thematic 3599-PPCDT by FEDER as part of the project FRESHCO: multiple implications of invasive species on Freshwater Mussel co-extinction processes (Contract: PTDC/AGRFOR/1627/2014). FCT also supported MLL under Grant (SFRH/BD/115728/2016)

Toll-Like Receptor 2, Toll-Like Receptor 4, Myeloid Differentiation Response Gene 88, and Toll-IL-1 Receptor Domain-Containing Adaptor-Inducing Interferon-gamma (TRIF) Selectively Regulate Susceptibility of PO106-125-Induced Murine Experimental Autoimmune Neuritis

The functional relevance of the innate immune system has not yet been dissected in PO106-125-induced murine experimental autoimmune neuritis. Therefore, the role of Toll-like receptor (TLR) 2, TLR4, myeloid differentiation response gene 88, and ToLL IL-1 receptor domain-containing adaptor-inducing interferon-i (TRIF), factors critically involved in the TLR signaling pathway, was studied in experimental autoimmune neuritis. In the absence of TLR2, TLR4, myeloid differentiation response gene 88, or TRIF, the clinical course was significantly attenuated compared to wild-type mice. This could be attributed to impaired NE-kappa B activation, as shown by the absence of nuclear translocation of ReIA with a decreased expression of IL-6, IL 12p40, and IL-17A. Remarkably, PO106-125-immunized TLR2(0/0) mice exhibited a delayed recovery as compared to TLR4(0/0) mice, which was because of an impaired T helper cell 2 polarization. Immunized TLR2(0/0) mice' were unable to induce OX40 and OX4OL by matrix metalloproteinase-2 on spLenic dendritic cells. Subsequently, M2 polarization was impaired and macrophages were unable to sufficiently induce T regulatory cells (T-regs). Thus, in the recovery phase, Tregs were significantly increased in TLR4(0/0) mice as compared to wild-type mice, whereas T-regs in immunized TLR2(0/0) mice were only slightly increased. Our data highlight the relevance of innate immunity and, especially, the tight interaction between the innate and the adaptive immune system, which should be considered for therapeutic approaches of autoimmune diseases