title: Stomach lysozymes of the three-toed sloth (Bradypus variegatus), an arboreal folivore from the Neotropics.
abstract: Lysozymes are antimicrobial defences that act as digestive enzymes when expressed in the stomach of herbivores with pre-gastric fermentation. We studied this enzyme in the complex stomach of the three-toed sloth (Bradypus variegatus), a folivore with pre-gastric fermentation. Lysozymes were identified by SDS-PAGE and immunoblotting in all portions: diverticulum, pouch, glandular and muscular prepyloric area with 14.3 kDa of molecular mass. Purified lysozymes from all areas but the diverticulum were characterized by MALDI-TOF, optimal pH, optimal ionic strength, and specific activity. The differences observed suggested at least three isoforms. The optimal pHs were similar to the pH of the stomach portion where the enzymes were isolated. The lysozyme from the pouch (fermentation chamber) exhibited higher specific activity and concentration than the others. The specific activity of the enzyme from the acid muscular prepyloric portion was comparable to that reported in the cow abomasums; however, its concentration was lower than that observed in cow. This distinctive pattern of secretion/specific activity and overall low concentration suggests different roles for the lysozymes in this herbivore compared to Artiodactyla. We postulate that sloth stomach lysozymes may still be antimicrobial defences by protecting the microbial flora of the fermentation chamber against foreign bacteria.
authors.affiliation: Laboratorio de Fisiología Gastrointestinal, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Apartado postal 21827, Caracas, 1020A, Venezuela; Centro de Cálculo Científico de la Universidad de Los Andes, Parque Tecnológico, Mérida 5101, Venezuela. Electronic address: mpacheco@cecalc.ula.ve.
authors.forename: M Andreína
authors.initials: MA
authors.lastname: Pacheco
authors.affiliation: Unidad de Bioquímica de Parásitos, Centro de Ingeniería Genética, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela.
authors.forename: Juan Luís
authors.initials: JL
authors.lastname: Concepción
authors.affiliation: Centro de Cálculo Científico de la Universidad de Los Andes, Parque Tecnológico, Mérida 5101, Venezuela; Unidad de Bioquímica de Parásitos, Centro de Ingeniería Genética, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela.
authors.forename: José David Rosales
authors.initials: JDR
authors.lastname: Rangel
authors.affiliation: Laboratorio de Fisiología Gastrointestinal, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Apartado postal 21827, Caracas, 1020A, Venezuela.
authors.forename: Marie Christine
authors.initials: MC
authors.lastname: Ruiz
authors.affiliation: Laboratorio de Fisiología Gastrointestinal, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Apartado postal 21827, Caracas, 1020A, Venezuela.
authors.forename: Fabián
authors.initials: F
authors.lastname: Michelangeli
authors.affiliation: Department of Biology, University of Puerto Rico, Río Piedras Campus, PO Box 23360, San Juan Puerto Rico, Puerto Rico 00931.
authors.forename: María G
authors.initials: MG
authors.lastname: Domínguez-Bello
mesh_terms: D000818:Animals; D015169:Colony Count, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D008297:Male; D013058:Mass Spectrometry; D009113:Muramidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D009994:Osmolar Concentration; D012896:Sloths / Q000378:metabolism*; D013270:Stomach / Q000201:enzymology* / Q000382:microbiology; D013997:Time Factors; D014020:Tissue Extracts; D014329:Tropical Climate
chemical_list: D014020:Tissue Extracts; D009113:Muramidase