声明
摘要
Abstract
Abbreviations
Table of contents
1．Literature review
1．1General description of cyanobacteria
1．1．1 Diverse cyanobaeteria from widespread habitats
1．1．2Evolutionary and ecological significance of cyanobacteria
1．1．3Diversity of natural products in cyanobacteria
1．2Ultraviolet radiation on organisms
1．2．1Positive effects of UV radiation on organisms
1．2．2Negative effects of UV radiation on organisms
1．2．3Tolerance mechanisms of UV in cyanobacteria
1．3UV absorbing compounds in cyanobacteria
1．4Scytonemins
1．5Mycosporine like amino acids(MAAs)
1．5．1Structures and photochemical properties of MAAs
1．5．2MAA production in organisms
1．5．3Genetic bases and biochemical pathways for MAA production
1．5．4 Regulation of MAA biosynthesis
1．5．5Functions of MAAs
1．6Aim of this study
2．UV-B enhanced production of unique mycosporine-like amino acids and carotenoids in the subaerial cyanobacterium Pseudanabaena sp.CCNU1
2．1Introduction
2．2Materials and Methods
2．2．1Sample collection andcyanobacterial isolation
2．2．2 Preparation of partial gene DNA
2．2．4MAA induction and extraction
2．2．5Characterization and detection of MAAS
2．2．6Measurements of total amount of UV-absorbing MAAs
2．2．8Statistical analysis
2．3Results
2．3．1Classification of newly cyanobacterial isolate
2．3．2Effects of UV-B radiation on MAA production
2．3．3Effects of UV-B radiation on carotenoid production
2．4Discussion
3．Characterization of mycosporine-like amino acids in chlorophyll f-producing cyanobacteria from shaded niches
3．1Introduction
3．2Materials And Methods
3．2．1Materials and culture conditions
3．2．2Microscopic observation and phylogenetic analysis
3．2．3Chlorophyll fluorescence measurements
3．2．4MAA extraction and induction
3．2．5Deteetion and characterization of MAAS
3．3．1Morphologies and 16S rDNA sequence similarities among Chroococcidiopsis strains
3．3．2UV-B tolerance assays
3．3．3MAA Induction
3．3．4MAA identification in Chroococcidiopsis strains
3．3．5MAA gene clusters in chlorophyll f-producing cyanobacteria
3．3．6No MAA induction in other chlorophyllf-producing cyanobacteria
3．4Discussion
4．Effects of nitrogen nutrient on the production of mycosporine-like amino acids in Nostoc species
4．1Introduction
4．2Materials and Methods
4．2．1Organism and culture conditions
4．2．2Measurement of chlorophyll fluorescence
4．2．3Induetion of MAAS under UV-B stress
4．2．4Extraction and identification of MAAs
4．3Results
4．3．2Induction of MAAS in Nostoc strains
4．3．3Characterization of MAAs in Nostoc strains
4．4Diseussion
Summary and Significance
References
Supplement 1
Supplement 2
Publications
Acknowledgements
华中师范大学;
