title: Characterisation of the secretome of the clam parasite, QPX.
abstract: Secreted and cell surface-associated molecules play a major role in disease development processes and host-pathogen interactions, and usually determine the virulence of invading organisms. In this study, we investigated proteins secreted by quahog parasite unknown, a thraustochytrid protist that infects the hard clam, Mercenaria mercenaria. In silico analysis of quahog parasite unknown transcripts predicted over 1200 proteins to possess an amino-terminal signal peptide which directs proteins into the classical eukaryotic secretory pathway. Proteomic analysis using LC/MS technology identified 56 proteins present in the extracellular secretion of quahog parasite unknown cells grown in vitro, including six mucin-like molecules, four glycosyl hydrolases and eight peptidases. Transcription levels of 19 quahog parasite unknown extracellular proteins were investigated in clam tissue lesions (in vivo) using quantitative PCR. The overexpression of six of these extracellular proteins in clam tissues compared with in vitro cultures suggests that they are involved in interaction with the clam host.
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, USA.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Rubin
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, USA.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Pales Espinosa
authors.affiliation: Proteomics Center, Stony Brook University, Stony Brook, NY 11794-5000, USA.
authors.forename: Antonius
authors.initials: A
authors.lastname: Koller
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, USA. Electronic address: Bassem.Allam@stonybrook.edu.
authors.forename: Bassem
authors.initials: B
authors.lastname: Allam
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D019295:Computational Biology; D020869:Gene Expression Profiling; D013058:Mass Spectrometry; D049891:Mercenaria / Q000469:parasitology*; D010271:Parasites / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D020543:Proteome / Q000032:analysis*; D040901:Proteomics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D011506:Proteins; D020543:Proteome; D012333:RNA, Messenger
keywords: Mass spectrometry; Mercenaria mercenaria; Secretome; Thraustochytrid; Virulence