Microdomains heterogeneity in the thylakoid membrane proteins visualized by super-resolution microscopy.

The investigation of spatial heterogeneity within the thylakoid membrane (TM) proteins has gained increasing attention in photosynthetic research. The recent advances in live-cell imaging have allowed the identification of heterogeneous organisation of photosystems in small cyanobacterial cells. These sub-micrometre TM regions, termed microdomains in cyanobacteria, exhibit functional similarities with granal (Photosystem II dominant) and stromal (Photosystem I dominant) regions observed in TM of higher plants.

Prochlorococcus marinus responses to light and oxygen.

Prochlorococcus marinus, the smallest picocyanobacterium, comprises multiple clades occupying distinct niches, currently across tropical and sub-tropical oligotrophic ocean regions, including Oxygen Minimum Zones. Ocean warming may open growth-permissive temperatures in new, poleward photic regimes, along with expanded Oxygen Minimum Zones. We used ocean metaproteomic data on current Prochlorococcus marinus niches, to guide testing of Prochlorococcus marinus growth across a matrix of peak irradiances, photoperiods, spectral bands and dissolved oxygen.

A Comprehensive Study of Light Quality Acclimation in Synechocystis Sp. PCC 6803.

Cyanobacteria play a key role in primary production in both oceans and fresh waters and hold great potential for sustainable production of a large number of commodities. During their life, cyanobacteria cells need to acclimate to a multitude of challenges, including shifts in intensity and quality of incident light. Despite our increasing understanding of metabolic regulation under various light regimes, detailed insight into fitness advantages and limitations under shifting light quality remains underexplored.

Crocosphaera watsonii - A widespread nitrogen-fixing unicellular marine cyanobacterium.

Crocosphaera watsonii is a unicellular N-fixing (diazotrophic) cyanobacterium observed in tropical and subtropical oligotrophic oceans. As a diazotroph, it can be a source of bioavailable nitrogen (N) to the microbial community in N-limited environments, and this may fuel primary production in the regions where it occurs. Crocosphaera watsonii has been the subject of intense study, both in culture and in field populations.

Immunocytochemical Visualization of Proteins from Cyanobacterial Cells with High Autofluorescence of Phycoerythrin and Phycourobilin.

Presented is a protocol for visualizing and quantifying a specific protein in cells at the cellular level for the marine cyanobacterium Crocosphaera watsonii, a crucial primary producer and nitrogen fixer in oligotrophic oceans. One of the challenges for marine autotrophic N2 fixers (diazotrophs) is distinguishing probe-derived fluorescence signals from autofluorescence. C.

Coexistence of Dominant Marine Phytoplankton Sustained by Nutrient Specialization.

and are the two dominant picocyanobacteria in the low-nutrient surface waters of the subtropical ocean, but the basis for their coexistence has not been quantitatively demonstrated. Here, we combine microcosm experiments and an ecological model to show that this coexistence can be sustained by specialization in the uptake of distinct nitrogen (N) substrates at low-level concentrations that prevail in subtropical environments. In field incubations, the response of both and to nanomolar N amendments demonstrates N limitation of growth in both populations.

Genomic capacities for Reactive Oxygen Species metabolism across marine phytoplankton.

Marine phytoplankton produce and scavenge Reactive Oxygen Species, to support cellular processes, while limiting damaging reactions. Some prokaryotic picophytoplankton have, however, lost all genes encoding scavenging of hydrogen peroxide. Such losses of metabolic function can only apply to Reactive Oxygen Species which potentially traverse the cell membrane outwards, before provoking damaging intracellular reactions.

Accumulation of Cyanobacterial Photosystem II Containing the 'Rogue' D1 Subunit Is Controlled by FtsH Protease and Synthesis of the Standard D1 Protein.

Unicellular diazotrophic cyanobacteria contribute significantly to the photosynthetic productivity of the ocean and the fixation of molecular nitrogen, with photosynthesis occurring during the day and nitrogen fixation during the night. In species like Crocosphaera watsonii WH8501, the decline in photosynthetic activity in the night is accompanied by the disassembly of oxygen-evolving photosystem II (PSII) complexes. Moreover, in the second half of the night phase, a small amount of rogue D1 (rD1), which is related to the standard form of the D1 subunit found in oxygen-evolving PSII, but of unknown function, accumulates but is quickly degraded at the start of the light phase.

Protection of nitrogenase from photosynthetic O evolution in : methodological pitfalls and advances over 30 years of research.

The genus comprises some of the most abundant N-fixing organisms in oligotrophic marine ecosystems. Since nitrogenase, the key enzyme for N fixation, is irreversibly inhibited upon O exposure, these organisms have to coordinate their N-fixing ability with simultaneous photosynthetic O production. Although being the principal object of many laboratory and field studies, the overall process of how reconciles these two mutually exclusive processes remains unresolved.

The balance between photosynthesis and respiration explains the niche differentiation between and .

and are both unicellular, nitrogen-fixing cyanobacteria that prefer different environments. Whereas mainly lives in nutrient-deplete, open oceans, is more common in coastal, nutrient-rich regions. Despite their physiological similarities, the factors separating their niches remain elusive.

as a Major Consumer of Fixed Nitrogen.

Crocosphaera watsonii (hereafter referred to as ) is a key nitrogen (N) fixer in the ocean, but its ability to consume combined-N sources is still unclear. Using microcosm incubations with an ecological model, we show that has high competitive capability both under low and moderately high combined-N concentrations. In field incubations, accounted for the highest consumption of ammonium and nitrate, followed by picoeukaryotes.

Diffusional Interactions among Marine Phytoplankton and Bacterioplankton: Modelling HO as a Case Study.

Marine phytoplankton vary widely in size across taxa, and in cell suspension densities across habitats and growth states. Cell suspension density and total biovolume determine the bulk influence of a phytoplankton community upon its environment. Cell suspension density also determines the intercellular spacings separating phytoplankton cells from each other, or from co-occurring bacterioplankton.

Erratum to "Quantifying growth under DIC limitation" [Comput. Struct. Biotechnol. J. 19 (2021) 6456-6464].

[This corrects the article DOI: 10.1016/j.csbj.

Electron & Biomass Dynamics of Under Interacting Nitrogen & Carbon Limitations.

Marine diazotrophs are a diverse group with key roles in biogeochemical fluxes linked to primary productivity. The unicellular, diazotrophic cyanobacterium is widely found in coastal, subtropical oceans. We analyze the consequences of diazotrophy on growth efficiency, compared to NO -supported growth in , to understand how cells cope with N-fixation when they also have to face carbon limitation, which may transiently affect populations in coastal environments or during blooms of phytoplankton communities.

Temporal Patterns and Intra- and Inter-Cellular Variability in Carbon and Nitrogen Assimilation by the Unicellular Cyanobacterium sp. ATCC 51142.

Unicellular nitrogen fixing cyanobacteria (UCYN) are abundant members of phytoplankton communities in a wide range of marine environments, including those with rapidly changing nitrogen (N) concentrations. We hypothesized that differences in N availability (N vs. combined N) would cause UCYN to shift strategies of intracellular N and C allocation.

Complex Response of the Chlorarachniophyte Bigelowiella natans to Iron Availability.

The productivity of the ocean is largely dependent on iron availability, and marine phytoplankton have evolved sophisticated mechanisms to cope with chronically low iron levels in vast regions of the open ocean. By analyzing the metabarcoding data generated from the Oceans expedition, we determined how the global distribution of the model marine chlorarachniophyte varies across regions with different iron concentrations. We performed a comprehensive proteomics analysis of the molecular mechanisms underpinning the adaptation of to iron scarcity and report on the temporal response of cells to iron enrichment.

Quantitative models of nitrogen-fixing organisms.

Nitrogen-fixing organisms are of importance to the environment, providing bioavailable nitrogen to the biosphere. Quantitative models have been used to complement the laboratory experiments and measurements, where such evaluations are difficult or costly. Here, we review the current state of the quantitative modeling of nitrogen-fixing organisms and ways to enhance the bridge between theoretical and empirical studies.

Heterogeneous nitrogen fixation rates confer energetic advantage and expanded ecological niche of unicellular diazotroph populations.

Nitrogen fixing plankton provide nitrogen to fuel marine ecosystems and biogeochemical cycles but the factors that constrain their growth and habitat remain poorly understood. Here we investigate the importance of metabolic specialization in unicellular diazotroph populations, using laboratory experiments and model simulations. In clonal cultures of Crocosphaera watsonii and Cyanothece sp.