Proteomic characterization of mucosal secretions in the eastern oyster, Crassostrea virginica

Abstract

The soft body surface of marine invertebrates is covered by a layer of mucus, a slippery gel secreted by mucocytes lining epithelia. The functions of this gel are diverse including locomotion, cleansing, food particles processing and defense against physicochemical injuries and infectious agents. In oysters, mucus covering pallial organs has been demonstrated to have a major importance in the processing of food particles and in the interactions with waterborne pathogens. Given the limited information available on mucus in bivalves and the apparent wide spectra of activity of bioactive molecules present in this matrix, the characterization of these mucosal secretions has become a research priority. In this study, mucus was separately collected from the mantle, gills and labial palps of the eastern oyster (Crassostrea virginica) and analyzed by liquid chromatography and tandem mass spectrometry. Results showed the presence of a wide variety of molecules involved in host-microbe interactions, including putative adhesion molecules (e.g. c-type lectins) confirming that transcripts previously identified in epithelial cells are translated into proteins secreted in mucus. Mucus composition was different among samples collected from different organs. These results generate a reference map for C. virginica pallial mucus to better characterize the various physiological functions of mucosal secretions.

The purplish bifurcate mussel Mytilisepta virgata gene expression atlas reveals a remarkable tissue functional specialization

“…Some bivalve lectin-encoding gene families are extremely expanded and comprise several hundred members, as suggested by proteomic [110] and transcriptome studies [20, 111, 112] and later confirmed on a whole genome scale in oyster [113]. The purplish Japanese mussel is no exception, as some important lectin-like gene families were also found among the most abundant ones in the de novo assembled transcriptome (Table 8).…”

Bivalve immunity and response to infections: Are we looking at the right place?

“…This is supported by a growing body of evidence highlighting the role mucosal microbiomes in regulating host resistance to infection either directly [microbe-microbe interactions; 69, 119, 120] or indirectly via immune stimulation and maturation [44]. Our current understanding underlines the diversity of immune effectors at molluscan mucosal interfaces [65] and highlights the tailored immune response to pathogen stimuli [62]. This context raises fascinating questions around host-microbe crosstalk and feedback controls of these interactions and may lead to novel disease mitigation strategies and improve the assessment of resistant crops or the screening of probiotic candidates.…”

Oysters and Vibrios as a Model for Disease Dynamics in Wild Animals

“…These act as a sieve, capturing food particles in the optimum range of 5-10 mm and moving them [ 2 0 _ T D $ D I F F ] towards the mouth [33]. In this process, mucus-and gill-associated microbiota may constitute a first defense against vibrios [42,43]. Thus, laboratory infection of animals where cultured bacteria are simply provided in a monoclonal state is unlikely to yield an accurate understanding of the factors that contribute to virulence.…”