AMMONIUM STIMULATION OF DARK CARBON FIXATION AS AN INDICATOR OF NITROGEN DEFICIENCY IN PHYTOPLANKTON: POTENTIAL ERRORS CAUSED BY AMMONIUM-OXIDIZING BACTERIA1

1991 ◽  
Vol 27 (1) ◽  
pp. 79-82 ◽  
Author(s):  
Walter K. Dodds ◽  
John C. Priscu
Keyword(s):  
Carbon Fixation ◽  
Nitrogen Deficiency ◽  
Dark Carbon Fixation ◽  
Ammonium Stimulation ◽  
Stimulation Of

scholarly journals Anoxygenic photo- and chemosynthesis of phototrophic sulfur bacteria from an alpine meromictic lake

2021 ◽  
Author(s):  
Francesco Di Nezio ◽  
Clarisse Beney ◽  
Samuele Roman ◽  
Francesco Danza ◽  
Antoine Buetti-Dinh ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Meromictic Lake ◽  
Purple Sulfur Bacterium ◽  
Phototrophic Sulfur Bacteria ◽  
Anaerobic Microorganisms ◽  
Sulfur Bacteria ◽  
Pure Cultures ◽  
Chlorobium Phaeobacteroides ◽  
Anoxic Environment ◽  
Dark Carbon Fixation

Abstract Meromictic lakes are interesting ecosystems to study anaerobic microorganisms due their permanent stratification allowing the formation of a stable anoxic environment. The crenogenic meromictic Lake Cadagno harbors an important community of anoxygenic phototrophic sulfur bacteria responsible for almost half of its total productivity. Besides their ability to fix CO2 through photosynthesis, these microorganisms also showed high rates of dark carbon fixation via chemosyntesis. Here, we grew in pure cultures three populations of anoxygenic phototrophic sulfur bacteria previously isolated from the lake, accounting for 72.8% of the total microbial community, and exibiting different phenotypes: 1) the motile, large-celled purple sulfur bacterium (PSB) Chromatium okenii, 2) the small-celled PSB Thiodictyon syntrophicum, and 3) the green sulfur bacterium (GSB) Chlorobium phaeobacteroides. We measured their ability to fix CO2 through photo- and chemo-synthesis, both in situ in the lake and in laboratory under different incubation conditions. We also evaluated the efficiency and velocity of H2S photo-oxidation, an important reaction in the anoxygenic photosynthesis process. Our results confirm that phototrophic sulfur bacteria strongly fix CO2 in the presence of light and that oxygen increases chemosynthesis at night, in laboratory conditions. Moreover, substancial differences were displayed between the three selected populations in terms of activity and abundance.

scholarly journals Microbial dark carbon fixation fueled by nitrate enrichment

2021 ◽  
Author(s):  
Joseph H. Vineis ◽  
Ashley N. Bulseco ◽  
Jennifer L. Bowen
Keyword(s):  
Microbial Communities ◽  
Marine Sediments ◽  
Salt Marshes ◽  
Carbon Fixation ◽  
Niche Partitioning ◽  
Coastal Marine Sediments ◽  
Functional Relationships ◽  
Coastal Marine ◽  
Dark Carbon Fixation ◽  
The Impact

Anthropogenic nitrate amendment to coastal marine sediments can increase rates of heterotrophic mineralization and autotrophic dark carbon fixation (DCF). DCF may be favored in sediments where organic matter is biologically unavailable, leading to a microbial community supported by chemoautotrophy. Niche partitioning among DCF communities and adaptations for nitrate metabolism in coastal marine sediments remain poorly characterized, especially within salt marshes. We used genome-resolved metagenomics, phylogenetics, and comparative genomics to characterize the potential niche space, phylogenetic relationships, and adaptations important to microbial communities within nitrate enriched sediment. We found that nitrate enrichment of sediment from discrete depths between 0-25 cm supported both heterotrophs and chemoautotrophs that use sulfur oxidizing denitrification to drive the Calvin-Benson-Bassham (CBB) or reductive TCA (rTCA) DCF pathways. Phylogenetic reconstruction indicated that the nitrate enriched community represented a small fraction of the phylogenetic diversity contained in coastal marine environmental genomes, while pangenomics revealed close evolutionary and functional relationships with DCF microbes in other oligotrophic environments. These results indicate that DCF can support coastal marine microbial communities and should be carefully considered when estimating the impact of nitrate on carbon cycling in these critical habitats.

Inorganic carbon fixation in ice-covered lakes of the McMurdo Dry Valleys

2019 ◽  
Vol 31 (3) ◽  
pp. 123-132 ◽  
Author(s):  
Trista J. Vick-Majors ◽  
John C. Priscu
Keyword(s):  
Aquatic Ecosystems ◽  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Dry Valleys ◽  
Ammonia Oxidizers ◽  
Fixed Carbon ◽  
Carbon Supply ◽  
Gain Energy ◽  
Photosynthetic Microorganisms ◽  
Dark Carbon Fixation

AbstractInorganic carbon fixation, usually mediated by photosynthetic microorganisms, is considered to form the base of the food chain in aquatic ecosystems. In high-latitude lakes, lack of sunlight owing to seasonal solar radiation limits the activity of photosynthetic plankton during the polar winter, causing respiration-driven demand for carbon to exceed supply. Here, we show that inorganic carbon fixation in the dark, driven by organisms that gain energy from chemical reactions rather than sunlight (chemolithoautotrophs), provides a significant influx of fixed carbon to two permanently ice-covered lakes (Fryxell and East Bonney). Fryxell, which has higher biomass per unit volume of water, had higher rates of inorganic dark carbon fixation by chemolithoautotrophs than East Bonney (trophogenic zone average 1.0 µg C l−1 d−1vs 0.08 µg C l−1 d−1, respectively). This contribution from dark carbon fixation was partly due to the activity of ammonia oxidizers, which are present in both lakes. Despite the potential importance of new carbon input by chemolithoautotrophic activity, both lakes remain net heterotrophic, with respiratory demand for carbon exceeding supply. Dark carbon fixation increased the ratio of new carbon supply to respiratory demand from 0.16 to 0.47 in Fryxell, and from 0.14 to 0.22 in East Bonney.

Ammonium Stimulation of Nitrate Reductase Induction in Excised Leaves of Wheat (Triticum aestivum)

1979 ◽  
Vol 93 (5) ◽  
pp. 395-402 ◽  
Author(s):  
S. Janaki Vijayaraghavan ◽  
Sudhir K. Sopory ◽  
Sipra Guha-Mukherjee
Keyword(s):  
Triticum Aestivum ◽  
Nitrate Reductase ◽  
Ammonium Stimulation ◽  
Stimulation Of

scholarly journals Nitrogen Deficiency in Culture Affects the Metabolic Pathways in Amphora Coffeaeformis for Biodiesel Production

2021 ◽  
Author(s):  
Kang Wang ◽  
Yulin Cui ◽  
Chunxiao Meng ◽  
Zhengquan Gao ◽  
Song Qin
Keyword(s):  
Molecular Mechanism ◽  
Lipid Accumulation ◽  
Ribosome Biogenesis ◽  
Carbon Fixation ◽  
Nitrogen Deficiency ◽  
Raw Material ◽  
Biodiesel Production ◽  
Microalgal Biodiesel ◽  
Amphora Coffeaeformis ◽  
Tag Accumulation

Abstract Background: Amphora coffeaeformis, a unicellular diatom, can accumulate large amounts of lipids under nitrogen (N) limitation, because of which it can act as a promising raw material for biodiesel production. However, the molecular mechanism underlying lipid accumulation in A. coffeaeformis remains unknown. Results: In this study, we investigated the mechanism underlying lipid accumulation under N deprivation conditions in A. coffeaeformis using RNA-seq. The results showed that the total lipid (TL) content of A. coffeaeformis in normal f/2 medium was 28.22% (TL/DW), which increased to 44.05% after 5 days of N deprivation, while the neutral lipid triacylglycerol (TAG) content increased from 10.41% (TAG/DW) to 25.21%. The transcriptional profile showed that 591 genes were up-regulated, with false discovery rate cutoff of 0.1%, and 1,021 genes were down-regulated, indicating that N deprivation induced wide-ranging reprogramming of regulation, and that most physiological activities were repressed. In addition, ribosome biogenesis, carbon fixation, and photosynthesis in A. coffeaeformis were considerably affected by N deprivation. Conclusions: In summary, the findings initially clarified the molecular mechanism of TAG accumulation and revealed the key genes involved in lipid metabolism in A. coffeaeformis, which will be useful in designing strategies for improving microalgal biodiesel production.

scholarly journals Dark Carbon Fixation: An Important Process in Lake Sediments

PLoS ONE ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. e65813 ◽  
Author(s):  
Ana Lúcia Santoro ◽  
David Bastviken ◽  
Cristian Gudasz ◽  
Lars Tranvik ◽  
Alex Enrich-Prast
Keyword(s):  
Lake Sediments ◽  
Carbon Fixation ◽  
Important Process ◽  
Dark Carbon Fixation

scholarly journals Morphological Plasticity in a Sulfur-Oxidizing Marine Bacterium from the SUP05 Clade Enhances Dark Carbon Fixation

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Vega Shah ◽  
Xiaowei Zhao ◽  
Rachel A. Lundeen ◽  
Anitra E. Ingalls ◽  
Daniela Nicastro ◽  
...  
Keyword(s):  
Cell Size ◽  
Metabolic Activity ◽  
Carbon Fixation ◽  
Electron Tomography ◽  
Morphological Plasticity ◽  
Chemosynthetic Bacteria ◽  
Minimum Zone ◽  
Sulfur Oxidizing ◽  
Dark Carbon Fixation ◽  
Oxygen Minimum

ABSTRACT Sulfur-oxidizing bacteria from the SUP05 clade are abundant in anoxic and oxygenated marine waters that appear to lack reduced sources of sulfur for cell growth. This raises questions about how these chemosynthetic bacteria survive across oxygen and sulfur gradients and how their mode of survival impacts the environment. Here, we use growth experiments, proteomics, and cryo-electron tomography to show that a SUP05 isolate, “Candidatus Thioglobus autotrophicus,” is amorphous in shape and several times larger and stores considerably more intracellular sulfur when it respires oxygen. We also show that these cells can use diverse sources of reduced organic and inorganic sulfur at submicromolar concentrations. Enhanced cell size, carbon content, and metabolic activity of the aerobic phenotype are likely facilitated by a stabilizing surface-layer (S-layer) and an uncharacterized form of FtsZ-less cell division that supports morphological plasticity. The additional sulfur storage provides an energy source that allows cells to continue metabolic activity when exogenous sulfur sources are not available. This metabolic flexibility leads to the production of more organic carbon in the ocean than is estimated based solely on their anaerobic phenotype. IMPORTANCE Identifying shifts in microbial metabolism across redox gradients will improve efforts to model marine oxygen minimum zone (OMZ) ecosystems. Here, we show that aerobic morphology and metabolism increase cell size, sulfur storage capacity, and carbon fixation rates in “Ca. Thioglobus autotrophicus,” a chemosynthetic bacterium from the SUP05 clade that crosses oxic-anoxic boundaries.

On the mechanism of ammonium stimulation of photosynthesis in isolated chloroplasts

1976 ◽  
Vol 7 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Emanuele De Benedetti ◽  
Giorgio Forti ◽  
Flavio M. Garlaschi ◽  
Luciana Rosa
Keyword(s):  
Ammonium Stimulation ◽  
Isolated Chloroplasts ◽  
Stimulation Of
Sign in / Sign up

Export Citation Format

Share Document