Better living through cyanothece - unicellular diazotrophic cyanobacteria with highly versatile metabolic systems.
نویسندگان
چکیده
Cyanothece sp. ATCC 51142 is a unicellular, diazotrophic cyanobacterium with a versatile metabolism and very pronounced diurnal rhythms. Since nitrogen fixation is exquisitely sensitive to oxygen, Cyanotheceutilizes temporal regulation to accommodate these incompatible processes in a single cell. When grown under 12 h light-dark (LD) periods, it performs photosynthesis during the day and N(2) fixation and respiration at night. Genome sequences of Cyanothece sp. ATCC 51142 and that of five other Cyanothece species have been completed and have produced some surprises. Analysis at both the transcriptomic and the proteomic levels in Cyanothece sp. ATCC 51142 has demonstrated the relationship of the metabolic synchrony with gene expression and has given us insights into diurnal and circadian regulation throughout a daily cycle. We are particularly interested in the regulation of metabolic processes, such as H(2) evolution, and the way in which these organisms respond to environmental cues, such as light, the lack of combined nitrogen, and changing O(2) levels. Cyanothece strains produce copious amounts of H(2) under different types of physiological conditions. Nitrogenase produces far more H(2) than the hydrogenase, in part because the nitrogenase levels are extremely high under N(2)-fixing conditions. With Cyanothece 51142 cultures grown in NO(3)-free media, either photoautotrophically or mixotrophically with glycerol, we have obtained H(2) production rates over 150 mumol/mg Chl/h.
منابع مشابه
Variations in the rhythms of respiration and nitrogen fixation in members of the unicellular diazotrophic cyanobacterial genus Cyanothece.
In order to accommodate the physiologically incompatible processes of photosynthesis and nitrogen fixation within the same cell, unicellular nitrogen-fixing cyanobacteria have to maintain a dynamic metabolic profile in the light as well as the dark phase of a diel cycle. The transition from the photosynthetic to the nitrogen-fixing phase is marked by the onset of various biochemical and regulat...
متن کاملVariations in the Rhythms of Respiration and Nitrogen Fixation in Members of the Unicellular Diazotrophic Cyanobacterial Genus Cyanothece1[W][OA]
In order to accommodate the physiologically incompatible processes of photosynthesis and nitrogen fixation within the same cell, unicellular nitrogen-fixing cyanobacteria have to maintain a dynamic metabolic profile in the light as well as the dark phase of a diel cycle. The transition from the photosynthetic to the nitrogen-fixing phase is marked by the onset of various biochemical and regulat...
متن کاملGenetic Transformation and Mutagenesis Via ssDNA in the Unicellular, Diazotrophic Cyanobacteria of the Genus Cyanothece
متن کامل
Genome-Scale Modeling of Light-Driven Reductant Partitioning and Carbon Fluxes in Diazotrophic Unicellular Cyanobacterium Cyanothece sp. ATCC 51142
Genome-scale metabolic models have proven useful for answering fundamental questions about metabolic capabilities of a variety of microorganisms, as well as informing their metabolic engineering. However, only a few models are available for oxygenic photosynthetic microorganisms, particularly in cyanobacteria in which photosynthetic and respiratory electron transport chains (ETC) share componen...
متن کاملThe genome of Cyanothece 51142, a unicellular diazotrophic cyanobacterium important in the marine nitrogen cycle.
Unicellular cyanobacteria have recently been recognized for their contributions to nitrogen fixation in marine environments, a function previously thought to be filled mainly by filamentous cyanobacteria such as Trichodesmium. To begin a systems level analysis of the physiology of the unicellular N(2)-fixing microbes, we have sequenced to completion the genome of Cyanothece sp. ATCC 51142, the ...
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عنوان ژورنال:
- Advances in experimental medicine and biology
دوره 675 شماره
صفحات -
تاریخ انتشار 2010