English   español  
Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/159676
COMPARTIR / IMPACTO:
Estadísticas
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:
Título

Digestive enzyme activity as a quantitative measure of protistan grazing: the acid lysozyme assay for bacterivory

AutorGonzález Grau, Juan Miguel ; Sherr, Evelyn; Sherr, Barry F.
Fecha de publicación1993
EditorInter Research
CitaciónMarine Ecology Progress Series 100: 197-206 (1993)
ResumenWe propose quantification of the activity of digestive enzymes as a novel way to estimate rates of protist grazing in natural waters. Our first application of this approach was determination of protistan bacterivory by assaying the activity of lysozyme at acid pH. Lysozyme specifically degrades peptidoglycan, a major structural component of prokaryotic cell walls. The basis of the method is determination of lysozyme activity present in protistan food vacuoles by using a fluorochrome-linked artificial substrate, 4-methylumbelhferyl β-D-N,N',N"-triacetylchitotriose (MUF-[GlcNAc]₃ as an analogue of peptidoglycan. Measurement of rate of MUF cleavage from the substrate in sonicated samples at acid pH (4.5) distinguishes activity of digestive enzymes present in protistan food vacuoles from extracellular or intracytoplasmic lysozyme activity. Acid lysozyme activity was calibrated against rate of bacterivory estimated using the fluorescently labeled bacteria (FLB) uptake method. Results from the 2 methods were significantly correlated (r² = 0.98) for both cultures of bacterivorous protists and for estuarine and nearshore seawater samples, over a wide range of rates of bacterivory (10³ to 10^6 bacteria /(ml h)) The relation between the 2 variables determined from water samples taken in open North Pacific gyre water had a higher slope compared to that of the other samples. The advantages of the acid lysozyme activity method are that it does not require in vivo incubations, manipulation of live samples, or microscopy, as do other current methods of estimating bacterivory, and that a large number of discrete samples can be quickly processed. Separate calibration of the assay, using alternate measures of bacterivory, is recommended for individual applications.
Descripción10 páginas.-- 4 figuras.-- 2 tablas.-- 48 referencias.-- El autor González Grau, Juan Miguel pertenece actualmente al Instituto de Recursos Naturales y Agrobiología de Sevilla
Versión del editorhttp://www.int-res.com/articles/meps/100/m100p197.pdf
URIhttp://hdl.handle.net/10261/159676
ISSN0171-8630
Aparece en las colecciones: (IRNAS) Artículos
Ficheros en este ítem:
Fichero Descripción Tamaño Formato  
accesoRestringido.pdf15,38 kBAdobe PDFVista previa
Visualizar/Abrir
Mostrar el registro completo
 


NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.