Hello everybody out there in cyto-world! I have a very specialized inquiry, but I hope thereīs somebody out there... We analyze phytoplankton with a BD FacsVantage, equipped with an Enterprise II laser at 488nm, and a red HeNe laser at 633nm. We trigger with red (=chlorophyll auto-) fluorescence of the blue laser which is collected at 675/20nm; now we have installed the red laser, whose red fluorescence signals are collected at 660/20nm. What we have observed in natural water samples from the North Sea is a distinct group which shows very strong red fluorescence signals when excited by the red laser. While the ratio of red fluorescence by red excitation (RFR) to that by blue excitation (RFB) is virtually the same for all other phytoplankton clusters (including our laboratory cultures of various taxonomic groups), the ratio is much higher for that specific group. Itīs a small (2-4ĩm) flagellate which shows no unusual fluorescence when excited by blue or green light by epifluorescence microscopy. We have sorted it and hope to grow it in culture to make an HPLC pigment examination. But until now they donīt grow... My questions: Has anybody seen something similar in natural samples or cultures? What emits at 660/20nm when excited by 633nm? Presumably Chl.b and phycocyanine (Hofstraat et al 1991, J. Fluor. 1(4), 249-265), but our cultured algae bearing these pigments did not behave that way. I know this is a very special problem, but maybe someone can help. Cheers, marcus ______________________________________________ Dr. Marcus Reckermann Research and Technology Center Westcoast (FTZ) Hafentoern, D-25761 Buesum, Germany E-Mail recker@ftz-west.uni-kiel.de Tel. +49-(0)4834-604-204 or -212 or -261 Fax. +49-(0)4834-604-299
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