Publisher Summary This chapter focuses on inclusions in carboxysomes. Inclusions with polygonal profiles (polyhedral bodies) appear to be ubiquitous entities of the vegetative cells and akinetes of cyanobacteria. Heterocysts, which fix nitrogen but not carbon dioxide, do not possess polyhedral bodies. From 3 to 12 (mean number) of these inclusions occur in the nucleoplasmic region of the cell. As observed in thin section, the bodies are 100-900 nm in diameter, have a granular substructure, and are surrounded by a monolayer membrane (shell) 3–4 nm thick. These inclusions have been isolated from Anabaena cylindrica and Chlorogloeopsisfritschii and shown to contain the enzyme ribulose-l,5-bisphosphate carboxylase (RuBisCOase), thus identifying them as carboxysomes as originally described in the autotrophic sulfur bacterium Thiobacillus neapolitanus. In addition to the carboxysomal (particulate) RuBisCOase, the cells possess a soluble form of the enzyme. The mechanism(s) of the formation as well as the loss of carboxysomes is unknown. The disappearance of the inclusions in Thiobacillus intermedius when RuBisCOase is repressed appears to be by dilution (unpublished observations). The function(s) of the carboxysome is also unknown. Several theories have been proposed based on a variety of experimental data, including (l) an active role in carbon dioxide fixation, providing a more favorable environment—for example, reducing oxygen availability or concentrating carbon dioxide, and (2) an inactive role in fixation but preventing exce...
Role In Fixation Thiobacillus Intermedius Reducing Oxygen Availability Granular Substructure Polygonal Profiles Anabaena Cylindrica Carbon Dioxide Fixation Polyhedral Bodies Monolayer Membrane Unpublished Observations
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Climate change Research Articles published between Nov 21, 2022 to Nov 27, 2022
Nov 28, 2022
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No potential conflict of interest was reported by the authors. The conception and design of the study, acquisition of data, analysis and interpretatio...Read More
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