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Fluorometric Characterization of Two Picocyanobacteria Strains from Lakes of Different Underwater Light Quality
Author(s) -
Callieri Cristiana,
Amicucci Enrica,
Bertoni Roberto,
Vörös Lajos
Publication year - 1996
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19960810103
Subject(s) - phycocyanin , phycoerythrin , fluorescence , picoplankton , pigment , phycobiliprotein , wavelength , irradiance , synechococcus , autofluorescence , chemistry , biology , materials science , cyanobacteria , phytoplankton , microbiology and biotechnology , optics , ecology , physics , bacteria , optoelectronics , nutrient , flow cytometry , genetics , organic chemistry
Unicellular autofluorescent picoplankton ranging from 0.6 to 0.9 ym in diameter were isolated from Lake Maggiore and from Lake Balaton. The cyanobacterial isolates contain two accessory pigments: phycoerythrin (PE) and phycocyanin (PC) respectively. The in vivo spectral properties of the two clones were compared to identify characteristics of the pigments. In vivo fluorescence excitation and emission spectra revealed that clones with PE are composed only of phycoerythrobilin chromophores and lack phycourobilin. Glycerol treatment enhances the fluorescence yield up to 3 times and improves the detection sensitivity of PE particularly at 436 and 520 nm and of PC at 600 nm. The vertical profiles of the underwater irradiance at different wavelengths were measured in both lakes to study the light quality of the natural environment of the two strains. Growth rates of both clones growing at different light intensities and wavelengths, selected by the same filters used for vertical profiles, were estimated. The results showed a difference in growth rate of phycoerythrin and phycocyanin containing cells exposed to an equal quantum flux of preferential illumination. In particular the maximum growth rate was reached by PE cells exposed to green light and by PC cells exposed to red light.