title: Presence of an isoform of H+-pyrophosphatase located in the alveolar sacs of a scuticociliate parasite of turbot: physiological consequences.
abstract: H+-pyrophosphatases (H+-PPases) are integral membrane proteins that couple pyrophosphate energy to an electrochemical gradient across biological membranes and promote the acidification of cellular compartments. Eukaryotic organisms, essentially plants and protozoan parasites, contain various types of H+-PPases associated with vacuoles, plasma membrane and acidic Ca+2 storage organelles called acidocalcisomes. We used Lysotracker Red DND-99 staining to identify two acidic cellular compartments in trophozoites of the marine scuticociliate parasite Philasterides dicentrarchi: the phagocytic vacuoles and the alveolar sacs. The membranes of these compartments also contain H+-PPase, which may promote acidification of these cell structures. We also demonstrated for the first time that the P. dicentrarchi H+-PPase has two isoforms: H+-PPase 1 and 2. Isoform 2, which is probably generated by splicing, is located in the membranes of the alveolar sacs and has an amino acid motif recognized by the H+-PPase-specific antibody PABHK. The amino acid sequences of different isolates of this ciliate are highly conserved. Gene and protein expression in this isoform are significantly regulated by variations in salinity, indicating a possible physiological role of this enzyme and the alveolar sacs in osmoregulation and salt tolerance in P. dicentrarchi.
authors.affiliation: Departamento de Microbiología y Parasitología,Instituto de Investigación y Análisis Alimentarios,Universidad de Santiago de Compostela,15782 Santiago De Compostela,Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Mallo
authors.affiliation: Departamento de Biología Celular y Ecología,Facultad de Biología,Instituto de Acuicultura,Universidad de Santiago de Compostela,15782 Santiago de Compostela,Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Lamas
authors.affiliation: Departamento de Microbiología y Parasitología,Instituto de Investigación y Análisis Alimentarios,Universidad de Santiago de Compostela,15782 Santiago De Compostela,Spain.
authors.forename: Ana-Paula
authors.initials: AP
authors.lastname: Defelipe
authors.affiliation: Departamento de Biología Celular y Molecular,Facultad de Ciencias,Universidad de A Coruña,15701 A Coruña,Spain.
authors.forename: Maria-Eugenia
authors.initials: ME
authors.lastname: Decastro
authors.affiliation: Departamento de Microbiología y Parasitología,Instituto de Investigación y Análisis Alimentarios,Universidad de Santiago de Compostela,15782 Santiago De Compostela,Spain.
authors.forename: Rosa-Ana
authors.initials: RA
authors.lastname: Sueiro
authors.affiliation: Departamento de Microbiología y Parasitología,Instituto de Investigación y Análisis Alimentarios,Universidad de Santiago de Compostela,15782 Santiago De Compostela,Spain.
authors.forename: José-Manuel
authors.initials: JM
authors.lastname: Leiro
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016770:Ciliophora Infections / Q000469:parasitology / Q000662:veterinary*; D016054:DNA, Protozoan / Q000032:analysis; D005393:Fish Diseases / Q000469:parasitology*; D005412:Flatfishes / Q000469:parasitology*; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D043564:Inorganic Pyrophosphatase / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D007527:Isoenzymes / Q000032:analysis; D051379:Mice; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal / Q000662:veterinary; D016253:Microscopy, Immunoelectron / Q000662:veterinary; D008969:Molecular Sequence Data; D016802:Oligohymenophorea / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D016053:RNA, Protozoan / Q000302:isolation & purification
chemical_list: D016054:DNA, Protozoan; D007527:Isoenzymes; D016053:RNA, Protozoan; D043564:Inorganic Pyrophosphatase
keywords: H+-PPase; Philasterides dicentrarchi; alveolar sacs; osmoregulation; turbot