Metabolic Mechanism Profiling Of Response In Nostoc Flagelliforme To Ultraviolet-B Radiation

In this study different ultraviolet B(UVB)intensity were used as critical regulatory factor to study its influence on photosynthesis,morphology,mycosporine-like amino acids(MAAs)synthesis in ostoc flagelliforme cells.The metabolism changes in cells under different UVB condition were also investigate combined with metabolim approach.It would provide more comprehensive information for UVB's reasonable application in its outdoor culturing.We investigated the effect of different UVB radiation intensity on pigment content and photosynthesis in Nostoc flagelliforme cells,cell morphology under UVB was observed by scanning electron microscope.It showed that Chla content decreased by 10.23%under UVB while synthesis of caroteniods was facilitated with the two folds content of the control.The content of APC and PC in cells under UVB both diminished with the valule of 46.68%and 18.37%.UVB with lower intensity improved respiratory rate by 19.21%while photosynthetic rate was decreased by 48.13%.Cells under SEM had wrinkles and sunken rough surface.At last cells gathered into layers with changed shape and diverse size.The synthesis of capsular polysaccharide and mycosporine amino acids(MAAs)in cells was facilitaed by UVB.Capsular polysaccharide content was improved by 55.92%under UVB with intensity of 3W/m2.Identification and quantification of MAAs were done by mass spectrometry.Asterine-330,shinorine and porphyra-334 were also existted in control and their synthesis was facilitated by UVB.Asterie-330 was most sensitive to UVB and its content increased by 400%.Gas chromatography-mass spectrometry combined with multivariate analysis was used to analyze the differences in metabolism of cells under different UVB radiation.It showed the increase in content of fatty acids and decrease in amino acids.UVB intensity made metabolism difference in cells,celullar carbohydrate and organic acid content under low-intensity UVB increased,while for higher one the content reduced.Protecting substances content within cells under low UVB intensity rose while they declined under higher UVB.