Fluorescence decay of dyed protozoa: differences between stressed and non-stressed cysts

Autor(es)

dos Santos, Samuel Ricardo ^{[1, 2]} ; Branco, Nilson ^[3] ; Bueno Franco, Regina Maura ^[3] ; Stipp Paterniani, Jose Euclides ^[1] ; Katsumata, Masakazu ^[4] ; Barlow, Peter W. ^[5] ; Gallep, Cristiano de Mello ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Sch Agr Engn, Campinas, SP - Brazil

^[2] Univ Estadual Campinas, Sch Technol, Limeira, SP - Brazil

^[3] Univ Estadual Campinas, Inst Biol, Campinas, SP - Brazil

^[4] Hamamatsu Photon KK, Cent Res Labs, Hamamatsu, Shizuoka - Japan

^[5] Univ Bristol, Sch Biol Sci, Bristol BS8 1TH, Avon - England

• Tipo de documento: Artigo Científico
• Fonte: LUMINESCENCE; v. 30, n. 7, p. 1139-1147, NOV 2015.
• Citações Web of Science: 1

Resumo

Several series of tests have shown that fresh, intact samples of Giardia duodenalis and Cryptosporidium parvum (oo) cysts are not marked by fluorescent probes such as carboxyfluorcein-succinimidyl-diacetate-ester (CFDA-SE), C12-resazurin and SYTOX (R) Green, probably because of their robust cell walls. These dyes fail to indicate the viability of such protozoa and allow negative responses to be recorded from living and infectious samples. Cryptosporidium parvum showed stronger isolation from chemicals, with living oocysts remaining unstained by the probe for up to 90 days after extraction. However, in further fluorescence decay (FD) experiments run with G. duodenalis samples stained using CFDA-SE (comprising living, non-stressed but aged cysts, heat-killed samples and UV-C-stressed samples) each showed a different FD decay profile, here studied in seven series of tests of five replicates each. The FD profiles were fitted by double-exponential decay kinetics, with the decay constant k(2) being five times higher than k(1). This FD procedure is fast and can be easily reproduced in 10 steps, taking similar to 1 h of laboratory work for already purified samples. Copyright (C) 2015 John Wiley \& Sons, Ltd. (AU)

• Processo FAPESP: 10/07792-1 - DETECÇÃO DA EMISSÃO ULTRAFRACA DE LUZ EM Giardia spp
• Beneficiário: Samuel Ricardo dos Santos
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/10763-6 - Biofotônica aplicada à parasitologia: medidas emissão ultra-fracas de luz em Cryptosporidium spp. e Giardia spp.
• Beneficiário: Cristiano de Mello Gallep
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/01501-3 - Emissão ultra-fraca de luz em protozoários
• Beneficiário: Samuel Ricardo dos Santos
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado