Title: Immunolocalization of the uptake hydrogenase in the marine Lyngbya majuscula CCAP 1446/4 and other cyanobacteria
Abstract:In N2-fixing cyanobacteria the reduction of N2 to NH3 is coupled with the production of molecular hydrogen (H2), which is rapidly consumed by an uptake hydrogenase, an enzyme that is present in almost...In N2-fixing cyanobacteria the reduction of N2 to NH3 is coupled with the production of molecular hydrogen (H2), which is rapidly consumed by an uptake hydrogenase, an enzyme that is present in almost all the diazotrophic cyanobacteria. The cellular and subcellular localization of the cyanobacterial uptake hydrogenase remains unclear, and the previously available data focuses mainly on heterocystous cyanobacteria. This work presents the first effort to localize the uptake hydrogenase in a nonheterocystous cyanobacterium, Lyngbya majuscula CCAP 1446/4. The data obtained revealed higher specific labelling associated with the thylakoid membranes of L. majuscula. As cyanobacteria exhibited a broad morphological diversity, and that may influence the cellular and sub-cellular localization of the uptake hydrogenase, a comparative analysis was performed using a unicellular Gloeothece sp. ATCC 27152, and two heterocystous strains Nostoc sp. PCC 7120 and Nostoc punctiforme PCC 73102. No labelling was found on the vegetative cells of Nostoc sp. PCC 7120, in contrast with the situation in N. punctiforme, in which labelling was detected in both vegetative cells and heterocysts. In addition, sequences of nifK, structural gene encoding the β subunit of the nitrogenase (enzymatic complex responsible for N2-fixation), were obtained for Lyngbya spp.. This work will allow additional studies, notably on the correlation between nitrogen fixation and hydrogen metabolism in non-heterocystous cyanobacteria, a line of research that is being followed by other members of the team. Unexpectedly, the images of L majuscula grown in medium containing combined nitrogen using electron microscopy, revealed the presence of an extremely high number of large cyanophycin granules, opening a window of opportunity for future research. The results presented within this work will contribute to a better understanding of the field of H2 metabolism in cyanobacteria, particularly in the non-heterocystous strains effecting a temporal separation between the photosynthesis and the N2 fixation/H2 uptake processes.Read More
Publication Year: 2009
Publication Date: 2009-02-11
Language: en
Type: dissertation
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot