Master 2 ème année : Sciences et Technologies Mention : Sciences de l’Univers, Environnement, Ecologie Spécialité : Océanographie et Environnement Marin UE Evolution of marine Phytoplankton & Biogeochemistry Research Worshop 2 : Chromatic Acclimation in Marine Cyanobacteria Christophe Six UMR UPMC-CNRS 7144 “Procaryotes Photosynthétiques Marins" Station Biologique de Roscoff Université Pierre et Marie Curie (Paris VI). Bureau 354, 3 ème étage (Batiment GT) six@sb-roscoff.fr
Research workshop 2 . Learning and understanding the scientific approach . Bringing out a scientific question from a scientific context . Setting up a experiment plan . Carring out the experiments . Synthetising and presenting the results . Interpreting the results . Communicating the results and their interpretation properly . Methods : culturing phytoplankton, flow cytometry and biophysics of photosynthesis . Results and interpretation : together . Personal work : a short report in the form of a research article � � � � Introduction , Methods, Results, Discussion � Article due by February 1 st on pdf Format at six@sb-roscoff.fr
60 0.01 1 Chl (mg/m 3 )
60 0.01 1 Chl (mg/m 3 ) However Synechococcus cells are detected everywhere ! 1,6 1,6 1,6 1,6 1,6 1,6 1,6 1,6 Pigment type 1 Pigment type 1 Type 1 (WH5701) Type 1 (WH5701) Type 1 (WH5701) Type 1 (WH5701) Type 1 (WH5701) Type 1 (WH5701) Type 1 (WH5701) Type 1 (WH5701) Col 8 vs Col 9 Col 8 vs Col 9 Col 8 vs Col 9 Col 8 vs Col 9 Col 8 vs Col 9 Col 8 vs Col 9 Col 8 vs Col 9 Col 8 vs Col 9 1,4 1,4 1,4 1,4 1,4 1,4 1,4 1,4 Pigment type 2 Pigment type 2 Relative absorbance (AU) Relative absorbance (AU) Relative absorbance (AU) Relative absorbance (AU) Relative absorbance (AU) Relative absorbance (AU) Relative absorbance (AU) Relative absorbance (AU) Type 2 (WH8018) Type 2 (WH8018) Type 2 (WH8018) Type 2 (WH8018) Type 2 (WH8018) Type 2 (WH8018) Type 2 (WH8018) Type 2 (WH8018) Col 8 vs Col 11 Col 8 vs Col 11 Col 8 vs Col 11 Col 8 vs Col 11 Col 8 vs Col 11 Col 8 vs Col 11 Col 8 vs Col 11 Col 8 vs Col 11 Type 3a (WH7803) Type 3a (WH7803) Type 3a (WH7803) Type 3a (WH7803) Pigment type 3a Pigment type 3a Type 3a (WH7803) Type 3a (WH7803) Type 3a (WH7803) Type 3a (WH7803) Col 8 vs Col 13 Col 8 vs Col 13 Col 8 vs Col 13 Col 8 vs Col 13 Col 8 vs Col 13 Col 8 vs Col 13 Col 8 vs Col 13 Col 8 vs Col 13 1,2 1,2 1,2 1,2 1,2 1,2 1,2 1,2 Col 8 vs Col 15 Col 8 vs Col 15 Col 8 vs Col 15 Col 8 vs Col 15 Col 8 vs Col 15 Col 8 vs Col 15 Col 8 vs Col 15 Col 8 vs Col 15 Type 3b (RCC307) Type 3b (RCC307) Pigment type 3b Type 3b (RCC307) Type 3b (RCC307) Pigment type 3b Type 3b (RCC307) Type 3b (RCC307) Type 3b (RCC307) Type 3b (RCC307) Col 8 vs Col 17 Col 8 vs Col 17 Col 8 vs Col 17 Col 8 vs Col 17 Col 8 vs Col 17 Col 8 vs Col 17 Col 8 vs Col 17 Col 8 vs Col 17 Type 3c (WH8102) Type 3c (WH8102) Type 3c (WH8102) Type 3c (WH8102) Type 3c (WH8102) Type 3c (WH8102) Type 3c (WH8102) Type 3c (WH8102) Pigment type 3c Pigment type 3c 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 0,8 0,8 0,8 0,8 0,8 0,8 0,8 0,8 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,2 0,2 0,2 0,2 0,2 0,2 0,2 0,2 0,0 0,0 0,0 0,0 0,0 0,0 0,0 0,0 400 400 400 400 400 400 400 400 450 450 450 450 450 450 450 450 500 500 500 500 500 500 500 500 550 550 550 550 550 550 550 550 600 600 600 600 600 600 600 600 650 650 650 650 650 650 650 650 700 700 700 700 700 700 700 700 750 750 750 750 750 750 750 750 Wavelength (nm) Wavelength (nm) Wavelength (nm) Wavelength (nm) Wavelength (nm) Wavelength (nm) Wavelength (nm) Wavelength (nm)
What is chromatic acclimation ? Chromatic acclimation is a physiological process that allows photosynthetic organisms, in particular cyanobacteria, to modulate their pigmentation in function of the environmental variations of spectral light quality . Freshwater cyanobacteria : - Publication by Nicole Tandeau de Marsac in 1977 - Between green light and red light - Between green light and red light -Variations of the ratio of phycobiliproteins : phycocyanin versus phycoerythrin - A lot of knowledge on this process Fremyella diplosiphon
What is chromatic acclimation ? Chromatic acclimation is a physiological process that allows photosynthetic organisms, in particular cyanobacteria, to modulate their pigmentation in function of the environmental variations of spectral light quality . Marine cyanobacteria : Synechococcus spp. - Recent discover : Brian Palenik in 2001 - Between blue light and green light - Variable ratio of phycobilins - Very little is known on this acclimation process Synechococcus sp.
Research Worshop 2 Photophysiology of marine picocyanobacteria : Chromatic acclimation among marine Synechococcus spp. Variations of the optical characteristics of light in seawater � � � � Does it influence cell growth (primary productivity) and how ? � Do all Synechococcus chromatic adapters carry out the same process ? Physiological diversity ? � Raising hypotheses : How do they do ? Influence of other physical factors ?
Research Worshop 2 Photophysiology of marine picocyanobacteria : Chromatic acclimation among marine Synechococcus spp. Comparison of 3 Synechococcus strains that chromatically acclimate: - Synechococcus sp. RCC2531 (M11.1) - Synechococcus sp. RCC2570 (MICROVIR 16CH_1) - Synechococcus sp. RCC515 (BL_107) Experimental protocole : Monitoring cultures of these three strains upon a shift of the spectral quality of light Blue Light � � � � Green Light Green Light � � Blue Light � � - Influence on growth - kinetics and specificities of acclimation
Research Worshop 2 Photophysiology of marine picocyanobacteria : Chromatic acclimation among marine Synechococcus spp. Culture monitoring Every morning, for 10 days � � Monitoring the variations of cell density : flow cytometry � � � Monitoring the variations of global optical properties : flow cytometry � � � � � Monitoring the phycobiliprotein fluorescence properties : spectrofluorimetry � �
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