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The impact of temperature and photosynthetically active radiation on the growth and pigments concentration in Baltic picocyanobacterium Synechococcus sp.

100%
Śliwińska-Wilczewska S., Cieszyńska A., Latała A.
Annales Universitatis Paedagogicae Cracoviensis Studia Naturae
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2017
EN
The experiments on three Baltic picocyanobacterial strains of Synechococcus (BA-120 – red strain, BA-124 – green strain and BA-132 – brown strain) were conducted at four scalar irradiances in Photosynthetically Active Radiation (PAR) and four temperature levels. The main aim of this work was to estimate the effect of environmental conditions (temperature and PAR) on cell concentration and photosynthetic pigments (Chlorophyll a – Chl a and Carotenoids – Car) contents. The ranges of PAR and temperatures were 10, 100, 190, 280 μmol m-2 s-1 and 10, 15, 20, 25ºC, respectively. The experiment was carried in a medium of salinity of 8. The number of Synechococcus sp. cells was determined using a BD Accuri™ C6 flow cytometer. The pigments contents were determined by a spectrophotometric method. In this work, it was found that elevated intensity and temperature have, on average, a positive effect on cell concentration for Synechococcus sp. The highest cells concentrations were noted at the highest PAR (280 µmol m-2 s-1) and the highest T (25ºC) for green and brown strains (BA-124 and BA-132, respectively) and at 190 µmol m-2 s-1 and 25ºC for red strain (BA-120). Comparing the strains at each PAR level and temperature, the highest cell concentration was noted in green strain (36·106 cell ml-1), while the lowest was observed in red strain (8·106 cell ml-1). In general, in the two strains of Synechococcus (BA-120 and BA-132), the highest Car and Chl a contents were observed at the lowest light intensity and the highest temperature. On the other hand, Car and Chl a maximum content in BA-124 were noted at the lowest light and temperature. The experiments on Synechococcus strains demonstrated their high capacity to acclimate to a wide range of PAR and temperature levels. The three strains of Synechococcus showed adaptation capabilities, since they were able to change the composition of their photosynthetic pigments to use light quantity better and to protect the cells from the unfavourable effect of elevated light and temperature.
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Allelopathic activity of the Baltic picocyanobacterium Synechocystis sp.

86%
Śliwińska-Wilczewska S., Knitter A., Cisło D., Latała A.
Annales Universitatis Paedagogicae Cracoviensis Studia Naturae
|
2017
EN
Allelopathic compounds produced by picocyanobacteria could affect the growth and development of biological systems. The main aim of this study was to investigate the influence of unknown allelochemicals obtained from picocyanobacterium Synechocystis sp. BA-153 in monocultures and in mixed cultures. In this study, we demonstrated that Synechocystis sp. BA-153 caused allelopathic effects against other strains of picocyanobacteria. It was found that Synechocystis sp. BA-121 was strongly inhibited by Synechocystis sp. BA-153 in both the mixed culture and cell-free filtrates. On the other hand, the addition of live picocyanobacterial culture of Synechocystis sp. BA-153 stimulated the growth of Synechocystis sp. BA-122. These results showed the allelopathic activity of Synechocystis sp. BA-153, which can cause either the inhibition or stimulation of growth of selected picoplanktonic cyanobacteria.
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Allelopathic effect of the Baltic picocyanobacterium Synechococcus sp. on selected diatoms

86%
Konarzewska Z., Śliwińska-Wilczewska S., Latała A.
Annales Universitatis Paedagogicae Cracoviensis Studia Naturae
|
2017
EN
It is commonly believed that the structure of phytoplankton and the formation of cyanobacterial and algal blooms may be explained by allelopathic interactions. The main aim of this study was to investigate the allelopathic effect of picocyanobacterium Synechococcus sp. on the following growth and fluorescence parameters: the maximum quantum yield of PSII photochemistry (Fv/Fm), and the effective quantum yield of PSII photochemistry (ΦPSII) of selected diatoms – Nitzschia fonticola, Fistulifera saprophila, Navicula perminuta and Amphora coffeaeformis. In this study, it was demonstrated that picocyanobacterium caused allelopathic effects against Baltic diatoms. The results showed that the addition of cell-free filtrate from Synechococcus sp. increased the number of cells of N. fonticola and F. saprophila. Moreover, it was found that picocyanobacterium was stimulated fluorescence parameters of N. fonticola, F. saprophila, and N. perminuta. On the other hand, it was noted that filtrate obtained from picocyanobacterium caused the inhibition of Fv/Fm parameter of A. coffeaeformis. The results of this experiment may provide further information about allelopathic interactions between Baltic picocyanobacteria and diatoms that are crucial to the understanding of algal blooms in aquatic ecosystems.
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