scholarly journals Anoxygenic Photosynthesis Controls Oxygenic Photosynthesis in a Cyanobacterium from a Sulfidic Spring

2015 ◽  
Vol 81 (6) ◽  
pp. 2025-2031 ◽  
Author(s):  
Judith M. Klatt ◽  
Mohammad A. A. Al-Najjar ◽  
Pelin Yilmaz ◽  
Gaute Lavik ◽  
Dirk de Beer ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Sulfur Cycle ◽  
Oxygenic Photosynthesis ◽  
Photic Zone ◽  
Ambient Light ◽  
Anoxygenic Photosynthesis ◽  
Content Type ◽  
Total Primary Productivity ◽  
Global Carbon ◽  
Kinetic Regulation

ABSTRACTBefore the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium,Pseudanabaenastrain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However,PseudanabaenaFS39 additionally assimilated NO3−during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life.

scholarly journals Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen

2021 ◽  
Author(s):  
LM Ward ◽  
PM Shih
Keyword(s):  
Carbon Fixation ◽  
Iron Oxidation ◽  
Green Sulfur Bacteria ◽  
Oxygenic Photosynthesis ◽  
Comparative Genomic ◽  
Anoxygenic Photosynthesis ◽  
Earth History ◽  
Sulfur Bacteria ◽  
Green Sulfur ◽  
Global Carbon

AbstractWhile most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, during the early parts of Earth history it is thought that anoxygenic photosynthesis—using compounds like ferrous iron or sulfide as electron donors—drove most global carbon fixation. Anoxygenic photosynthesis is still performed by diverse bacteria in niche environments today. Of these, the Chlorobi (formerly green sulfur bacteria) are often interpreted as being particularly ancient and are frequently proposed to have fueled the biosphere early in Earth history before the rise of oxygenic photosynthesis. Here, we perform comparative genomic, phylogenetic, and molecular clock analyses to determine the antiquity of the Chlorobi and their characteristic phenotypes. We show that contrary to common assumptions, the Chlorobi clade is relatively young, with anoxygenic phototrophy, carbon fixation via the rTCA pathway, and iron oxidation all significantly postdating the rise of oxygen ~2.3 billion years ago. The Chlorobi therefore could not have fueled the Archean biosphere, but instead represent a relatively young radiation of organisms which likely acquired the capacity for anoxygenic photosynthesis and other traits via horizontal gene transfer sometime after the evolution of oxygenic Cyanobacteria.

scholarly journals FITOPLANKTON DAN SIKLUS KARBON GLOBAL

OSEANA ◽  
2019 ◽  
Vol 44 (2) ◽  
pp. 35-48
Author(s):  
Mochamad Ramdhan Firdaus ◽  
Lady Ayu Sri Wijayanti
Keyword(s):  
Carbon Cycle ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Sedimentary Rocks ◽  
Global Carbon Cycle ◽  
Biological Pump ◽  
Large Role ◽  
The World ◽  
Pump Mechanism ◽  
Global Carbon

PHYTOPLANKTON AND GLOBAL CARBON CYCLE. Scientists around the world believe that phytoplankton, although microscopic, have a large role in the global carbon cycle. Various research results show that the net primary productivity of all phytoplankton in the sea is almost as large as the net primary productivity of all plants on land. Phytoplankton through the process of photosynthesis absorbs 40-50 PgC / year from the atmosphere. Also, phytoplankton is known to be responsible for transporting carbon from the atmosphere to the seafloor through the carbon biological pump mechanism. Phytoplankton from the coccolithophores group is known to play a role in the sequestration of carbon on the seabed through the carbonate pump mechanism. The mechanism is capable of sequestering carbon for thousands of years on the seabed in the form of sedimentary rocks (limestone).

scholarly journals Brief review of phototrophs in the Crimean hypersaline lakesand lagoons: diversity, ecological role, the possibility of using

2017 ◽  
Vol 2 (2) ◽  
pp. 80-85 ◽  
Author(s):  
N. V. Shadrin ◽  
E. V. Anufriieva ◽  
S. N. Shadrina
Keyword(s):  
Secondary Metabolites ◽  
Oxygenic Photosynthesis ◽  
Green Bacteria ◽  
Ecological Role ◽  
Anoxygenic Photosynthesis ◽  
Adaptive Mechanisms ◽  
Different Types ◽  
Extreme Habitats

Widespread, including in Crimea, hypersaline waters are among the most extreme habitats of the planet. The need to adapt organisms to living in polyextreme environment has led to the development of a variety of adaptive mechanisms with a synthesis of unique secondary metabolites, which makes organisms dwelling hypersaline waters very promising to use them in different areas of biotechnology and aquaculture. There are three groups of phototrophs using different types of phototrophy in the Crimean hypersaline waters: oxygenic photosynthesis (cyanobacteria, microalgae, and plants), anoxygenic photosynthesis (purple and green bacteria) and proton bacteriorhodopsin pump (archaea). Diversity and roles of these groups in the Crimean lakes and lagoons as well as some perspectives of their practical use are discussed.

Global biosphere primary productivity over the last 800,000 years reconstructed from the triple-isotope composition of dioxygen trapped in polar ice cores

2021 ◽  
Author(s):  
Ji-Woong Yang ◽  
Amaëlle Landais ◽  
Margaux Brandon ◽  
Thomas Blunier ◽  
Frédéric Prié ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Isotope Composition ◽  
Atmospheric Oxygen ◽  
Ice Cores ◽  
Oxygenic Photosynthesis ◽  
Time Interval ◽  
Polar Ice ◽  
Future Evolution ◽  
Glacial Stage ◽  
Glacial Periods

<p>The primary production, or oxygenic photosynthesis of the global biosphere, is one of the main source and sink of atmospheric oxygen (O<sub>2</sub>) and carbon dioxide (CO<sub>2</sub>), respectively. There has been a growing number of evidence that global gross primary productivity (GPP) varies in response to climate change. It is therefore important to understand the climate- and/or environment controls of the global biosphere primary productivity for better predicting the future evolution of biosphere carbon uptake. The triple-isotope composition of O<sub>2</sub> (Δ<sup>17</sup>O of O<sub>2</sub>) trapped in polar ice cores allows us to trace the past changes of global biosphere primary productivity as far back as 800,000 years before present (800 ka). Previously available Δ<sup>17</sup>O of O<sub>2</sub> records over the last ca. 450 ka show relatively low and high global biosphere productivity over the last five glacial and interglacial intervals respectively, with a unique pattern over Termination V (TV) - Marine Isotopic Stage (MIS) 11, as biosphere productivity at the end of TV is ~ 20 % higher than the four younger ones (Blunier et al., 2012; Brandon et al., 2020). However, questions remain on (1) whether the concomitant changes of global biosphere productivity and CO<sub>2</sub> were the pervasive feature of glacial periods over the last 800 ka, and (2) whether the global biosphere productivity during the “lukewarm” interglacials before the Mid-Brunhes Event (MBE) were lower than those after the MBE.<br>Here, we present an extended composite record of Δ<sup>17</sup>O of O<sub>2</sub> covering the last 800 ka, based on new Δ<sup>17</sup>O of O<sub>2</sub> results from the EPICA Dome C and reconstruct the evolution of global biosphere productivity over that time interval using the independent box models of Landais et al. (2007) and Blunier et al. (2012). We find that the glacial productivity minima occurred nearly synchronously with the glacial CO<sub>2</sub> minima at mid-glacial stage; interestingly millennia before the sea level reaches their minima. Following the mid-glacial minima, we also show slight productivity increases at the full-glacial stages, before deglacial productivity rises. Comparison of reconstructed interglacial productivity demonstrates a slightly higher productivity over the post-MBE (MISs 1, 5, 7, 9, and 11) than pre-MBE ones (MISs 13, 15, 17, and 19). However, the mean difference between post- and pre-MBE interglacials largely depends on the box model used for productivity reconstruction.</p>

scholarly journals A Tripartite, Hierarchical Sigma Factor Cascade Promotes Hormogonium Development in the Filamentous Cyanobacterium Nostoc punctiforme

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Alfonso Gonzalez ◽  
Kelsey W. Riley ◽  
Thomas V. Harwood ◽  
Esthefani G. Zuniga ◽  
Douglas D. Risser
Keyword(s):  
Sigma Factor ◽  
Dominant Role ◽  
Sigma Factors ◽  
Oxygenic Photosynthesis ◽  
Model Organisms ◽  
Filamentous Cyanobacterium ◽  
Nostoc Punctiforme ◽  
Filamentous Cyanobacteria ◽  
Content Type ◽  
Nitrogen Cycles

ABSTRACT Cyanobacteria are prokaryotes capable of oxygenic photosynthesis, and frequently, nitrogen fixation as well. As a result, they contribute substantially to global primary production and nitrogen cycles. Furthermore, the multicellular filamentous cyanobacteria in taxonomic subsections IV and V are developmentally complex, exhibiting an array of differentiated cell types and filaments, including motile hormogonia, making them valuable model organisms for studying development. To investigate the role of sigma factors in the gene regulatory network (GRN) controlling hormogonium development, a combination of genetic, immunological, and time-resolved transcriptomic analyses were conducted in the model filamentous cyanobacterium Nostoc punctiforme, which, unlike other common model cyanobacteria, retains the developmental complexity of field isolates. The results support a model where the hormogonium GRN is driven by a hierarchal sigma factor cascade, with sigJ activating the expression of both sigC and sigF, as well as a substantial portion of additional hormogonium-specific genes, including those driving changes to cellular architecture. In turn, sigC regulates smaller subsets of genes for several processes, plays a dominant role in promoting reductive cell division, and may also both positively and negatively regulate sigJ to reinforce the developmental program and coordinate the timing of gene expression, respectively. In contrast, the sigF regulon is extremely limited. Among genes with characterized roles in hormogonium development, only pilA shows stringent sigF dependence. For sigJ-dependent genes, a putative consensus promoter was also identified, consisting primarily of a highly conserved extended −10 region, here designated a J-Box, which is widely distributed among diverse members of the cyanobacterial lineage. IMPORTANCE Cyanobacteria are integral to global carbon and nitrogen cycles, and their metabolic capacity coupled with their ease of genetic manipulation make them attractive platforms for applications such as biomaterial and biofertilizer production. Achieving these goals will likely require a detailed understanding and precise rewiring of these organisms’ GRNs. The complex phenotypic plasticity of filamentous cyanobacteria has also made them valuable models of prokaryotic development. However, current research has been limited by focusing primarily on a handful of model strains which fail to reflect the phenotypes of field counterparts, potentially limiting biotechnological advances and a more comprehensive understanding of developmental complexity. Here, using Nostoc punctiforme, a model filamentous cyanobacterium that retains the developmental range of wild isolates, we define previously unknown definitive roles for a trio of sigma factors during hormogonium development. These findings substantially advance our understanding of cyanobacterial development and gene regulation and could be leveraged for future applications.

scholarly journals Draft Genome Sequence of an Indian Marine Cyanobacterial Strain with Fast Growth and High Polyglucan Content

2017 ◽  
Vol 5 (47) ◽  
Author(s):  
Ruchi Pathania ◽  
Ahmad Ahmad ◽  
Shireesh Srivastava
Keyword(s):  
Genome Sequence ◽  
Draft Genome ◽  
Fast Growth ◽  
Marine Cyanobacteria ◽  
Cyanobacterial Strain ◽  
Draft Sequence ◽  
Marine Cyanobacterium ◽  
Content Type ◽  
Potential Source ◽  
Global Carbon

ABSTRACT Marine cyanobacteria play an important role in global carbon cycling and are a potential source of polyglucans for biotechnological purposes. This report provides the draft sequence of an Indian marine cyanobacterium, Synechococcus elongatus BDU 130192, which shows fast growth and high polyglucan content. The genome sequence will help in understanding the unique properties of this organism.

scholarly journals Aquatic and terrestrial cyanobacteria produce methane

2020 ◽  
Vol 6 (3) ◽  
pp. eaax5343 ◽  
Author(s):  
M. Bižić ◽  
T. Klintzsch ◽  
D. Ionescu ◽  
M. Y. Hindiyeh ◽  
M. Günthel ◽  
...  
Keyword(s):  
Surface Waters ◽  
Primary Productivity ◽  
Methane Production ◽  
Isotope Labeling ◽  
Cyanobacterial Blooms ◽  
Oxygenic Photosynthesis ◽  
Strictly Anaerobic ◽  
Terrestrial Cyanobacteria ◽  
Methane Budget ◽  
Terrestrial Environments

Evidence is accumulating to challenge the paradigm that biogenic methanogenesis, considered a strictly anaerobic process, is exclusive to archaea. We demonstrate that cyanobacteria living in marine, freshwater, and terrestrial environments produce methane at substantial rates under light, dark, oxic, and anoxic conditions, linking methane production with light-driven primary productivity in a globally relevant and ancient group of photoautotrophs. Methane production, attributed to cyanobacteria using stable isotope labeling techniques, was enhanced during oxygenic photosynthesis. We suggest that the formation of methane by cyanobacteria contributes to methane accumulation in oxygen-saturated marine and limnic surface waters. In these environments, frequent cyanobacterial blooms are predicted to further increase because of global warming potentially having a direct positive feedback on climate change. We conclude that this newly identified source contributes to the current natural methane budget and most likely has been producing methane since cyanobacteria first evolved on Earth.

scholarly journals Microbial Iron Oxidation in the Arctic Tundra and Its Implications for Biogeochemical Cycling

2015 ◽  
Vol 81 (23) ◽  
pp. 8066-8075 ◽  
Author(s):  
David Emerson ◽  
Jarrod J. Scott ◽  
Joshua Benes ◽  
William B. Bowden
Keyword(s):  
Relative Abundance ◽  
Iron Oxidation ◽  
Arctic Tundra ◽  
16S Rrna Genes ◽  
The Arctic ◽  
Rrna Genes ◽  
Oxygenic Photosynthesis ◽  
Field Station ◽  
Content Type ◽  
Microbial Iron Oxidation

ABSTRACTThe role that neutrophilic iron-oxidizing bacteria play in the Arctic tundra is unknown. This study surveyed chemosynthetic iron-oxidizing communities at the North Slope of Alaska near Toolik Field Station (TFS) at Toolik Lake (lat 68.63, long −149.60). Microbial iron mats were common in submerged habitats with stationary or slowly flowing water, and their greatest areal extent is in coating plant stems and sediments in wet sedge meadows. Some Fe-oxidizing bacteria (FeOB) produce easily recognized sheath or stalk morphotypes that were present and dominant in all the mats we observed. The cool water temperatures (9 to 11°C) and reduced pH (5.0 to 6.6) at all sites kinetically favor microbial iron oxidation. A microbial survey of five sites based on 16S rRNA genes found a predominance ofProteobacteria, withBetaproteobacteriaand members of the familyComamonadaceaebeing the most prevalent operational taxonomic units (OTUs). In relative abundance, clades of lithotrophic FeOB composed 5 to 10% of the communities. OTUs related to cyanobacteria and chloroplasts accounted for 3 to 25% of the communities. Oxygen profiles showed evidence for oxygenic photosynthesis at the surface of some mats, indicating the coexistence of photosynthetic and FeOB populations. The relative abundance of OTUs belonging to putative Fe-reducing bacteria (FeRB) averaged around 11% in the sampled iron mats. Mats incubated anaerobically with 10 mM acetate rapidly initiated Fe reduction, indicating that active iron cycling is likely. The prevalence of iron mats on the tundra might impact the carbon cycle through lithoautotrophic chemosynthesis, anaerobic respiration of organic carbon coupled to iron reduction, and the suppression of methanogenesis, and it potentially influences phosphorus dynamics through the adsorption of phosphorus to iron oxides.

scholarly journals Characterization of Planctomyces limnophilus and Development of Genetic Tools for Its Manipulation Establish It as a Model Species for the Phylum Planctomycetes

2011 ◽  
Vol 77 (16) ◽  
pp. 5826-5829 ◽  
Author(s):  
Christian Jogler ◽  
Frank Oliver Glöckner ◽  
Roberto Kolter
Keyword(s):  
Eukaryotic Cells ◽  
Cellular Structures ◽  
Model Species ◽  
Content Type ◽  
Genetic Tools ◽  
Carbon And Nitrogen ◽  
Nitrogen Cycles ◽  
Global Carbon ◽  
The Phylum Planctomycetes

ABSTRACTPlanctomycetesrepresent a remarkable clade in the domainBacteriabecause they play crucial roles in global carbon and nitrogen cycles and display cellular structures that closely parallel those of eukaryotic cells. Studies onPlanctomyceteshave been hampered by the lack of genetic tools, which we developed forPlanctomyces limnophilus.

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