The analysis of phenotypic plasticity between the nitrogen fixation and the toxic production abilities in cyanobacteria using a single-cell device

2015 Fiscal Year Final Research Report

• Project/Area Number: 26650156
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Ecology/Environment
• Research Institution: The University of Tokyo
• Principal Investigator: OHBAYASHI Kako 東京大学, 総合文化研究科, 学術研究員 (20448202)
• Co-Investigator(Renkei-kenkyūsha): SHIMADA Masakazu 東京大学, 大学院総合文化研究科, 教授 (40178950) ; WAKAMOTO Yuichi 東京大学, 大学院総合文化研究科, 准教授 (30517884) ; HODOKI Yoshikuni 京都大学, 生態学研究センター, 特定准教授 (60632122)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: シアノバクテリア / 表現型可塑性 / 窒素固定能 / 毒生産能 / シアノトキシン / アナトキシン

Outline of Final Research Achievements

Cyanobacteria have both nitrogen fixation and toxin production abilities which are acquired by their ancestral species, and those abilities are thought to be primitive characteristics. However, according the phylogenetic analysis these abilities have been lost in many taxonomic groups of cyanobacteria. We hypothesized that there might be some kind of cost to maintain both abilities in a species. We analyzed this hypothesis using a cyanobacterial strain, Cuspidothrix issatschenkoi RM6 strain with non-nitrogen fixing and toxin (anatoxin-a) producing abilities. We measured cell size using a single-cell device and tried to make a genetic modified strain of RM6 and analyzed the amount of anatoxin-a gene expression under different nutrient conditions. Increased anatoxin-a gene expressions were observed under non nitrogen conditions, though these expressions were observed to decrease under non phosphate conditions.

Free Research Field

進化生態学