Meeting Abstract
Mucosal tissues represent the major interface for exchange between animals and their environment and mucus itself is one of the most important lines of defense against microbes. Mucus is produced from virtually all molluscan epithelia and plays a role in several biological functions such as locomotion and navigation, freeze protection, attachment and defense against predators. In filter-feeding bivalves, copious amounts of mucus are produced by pallial organs (gills, mantle, palps) to help process waterborne microbes. This presentation will summarize our findings on the role of pallial mucus in interactions with waterborne microbes in the framework of predator-prey and host-pathogen associations. Our results showed the presence in pallial mucus of lectins that bind glycans associated with the cell surface of microalgae allowing selective processing and mediating the sorting of food particles in suspension-feeding oysters and mussels. In parallel, we demonstrated that mucus factors can serve as triggers for the activation of adapted microbes to initiate host colonization and invasion. For example, significant regulation of the proliferation and virulence was recorded in the alveolate parasite Perkinsus marinus following exposure to oyster mucus. While the pallial mucus of the susceptible oysters (Crassostrea virginica) enhanced the growth and the virulence of the parasite, mucus from resistant oysters (C. gigas) was strongly inhibitory suggesting that P. marinus host specificity may begin in the mucus. Evidence also suggests a dynamic regulation of mucus factors in response to intrinsic and extrinsic triggers. This context raises fascinating questions around host-microbe crosstalk and feedback controls of these interactions and calls for appealing inquisitive research in the years to come.
