The effect of oxygen concentration and temperature on nitrogenase activity in the heterocystous cyanobacterium Fischerella sp.

Stal, Lucas J.

doi:10.1038/s41598-017-05715-0

Cited by 34 publications

(24 citation statements)

References 32 publications

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“…To the best of our knowledge these isolates has been reported as cold adapted but not with nitrogen fixing attribute. Further, nitrogen fixation is an enzymatic process and negatively affected by temperature other than the optimal temperature for nitrogenase [ 37 ]. However, growth in nitrogen deficient medium at 2°C revealed that the nitrogen fixation machinery in these bacteria was least affected by very low temperature.…”

Section: Discussionmentioning

confidence: 99%

Microbial diversity and soil physiochemical characteristic of higher altitude

et al. 2019

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Altitude is the major factor affecting both biodiversity and soil physiochemical properties of soil ecosystems. In order to understand the effect of altitude on soil physiochemical properties and bacterial diversity across the Himalayan cold desert, high altitude Gangotri soil ecosystem was studied and compared with the moderate altitude Kandakhal soil. Soil physiochemical analysis showed that altitude was positively correlated with soil pH, organic matter and total nitrogen content. However soil mineral nutrients and soil phosphorus were negatively correlated to the altitude. RT-PCR based analysis revealed the decreased bacterial and diazotrophic abundance at high altitude. Metagenomic study showed that Proteobacteria, Acidobacteria and Actinobacteria were dominant bacteria phyla at high altitude soil while Bacteroidetes and Fermicutes were found dominant at low altitude. High ratio of Gram-negative to Gram positive bacteria at Gangotri suggests the selective proliferation of Gram negative bacteria at high altitude with decrease in Gram positive bacteria. Moreover, Alphaproteobacteria was found more abundant at high altitude while the opposite was true for Betaproteobacteria. Abundance of Cytophaga, Flavobacterium and Bacteroides (CFB) were also found comparatively high at high altitude. Presence of many taxonomically unclassified sequences in Gangotri soil indicates the presence of novel bacterial diversity at high altitude. Further, isolation of bacteria through indigenously designed diffusion chamber revealed the existence of bacteria which has been documented in unculturable study of WIH (Western Indian Himalaya) but never been cultivated from WIH. Nevertheless, diverse functional free-living psychrotrophic diazotrophs were isolated only from the high altitude Gangotri soil. Molecular characterization revealed them as Arthrobacter humicola, Brevibacillus invocatus, Pseudomonas mandelii and Pseudomonas helmanticensis. Thus, this study documented the bacterial and psychrophilic diazotrophic diversity at high altitude and is an effort for exploration of low temperature bacteria in agricultural productivity with the target for sustainable hill agriculture.

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Section: Discussionmentioning

confidence: 99%

Microbial diversity and soil physiochemical characteristic of higher altitude

et al. 2019

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“…Photosystem I-dependent reduction of FdxH requires donation of electrons by NAD(P)H into an electron transport chain involving NAD(P)H dehydrogenase and cytochrome b 6 -f complexes. Energy conservation associated with this electron transport chain and with the operation of respiratory oxidases results in production of ATP that is also needed for nitrogenase function (Magnuson and Cardona, 2016;Valladares et al, 2007;Stal, 2017).…”

Section: Heterocyst Differentiation and Functionmentioning

confidence: 99%

Genetic responses to carbon and nitrogen availability in Anabaena

Herrero

Flores

2018

Environmental Microbiology

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Heterocyst-forming cyanobacteria are filamentous organisms that perform oxygenic photosynthesis and CO fixation in vegetative cells and nitrogen fixation in heterocysts, which are formed under deprivation of combined nitrogen. These organisms can acclimate to use different sources of nitrogen and respond to different levels of CO . Following work mainly done with the best studied heterocyst-forming cyanobacterium, Anabaena, here we summarize the mechanisms of assimilation of ammonium, nitrate, urea and N , the latter involving heterocyst differentiation, and describe aspects of CO assimilation that involves a carbon concentration mechanism. These processes are subjected to regulation establishing a hierarchy in the assimilation of nitrogen sources -with preference for the most reduced nitrogen forms- and a dependence on sufficient carbon. This regulation largely takes place at the level of gene expression and is exerted by a variety of transcription factors, including global and pathway-specific transcriptional regulators. NtcA is a CRP-family protein that adjusts global gene expression in response to the C-to-N balance in the cells, and PacR is a LysR-family transcriptional regulator (LTTR) that extensively acclimates the cells to oxygenic phototrophy. A cyanobacterial-specific transcription factor, HetR, is involved in heterocyst differentiation, and other LTTR factors are specifically involved in nitrate and CO assimilation.

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“…All aerobic nitrogen fixation occurs in heterocysts in a semiregular pattern, and nitrogen fixed in heterocysts is transported to vegetative cells in the filament; vegetative cells supply carbon and reductants to heterocysts [ 6 , 9 ]. The heterocyst is the site of dinitrogen fixation and provides oxygen-sensitive nitrogenase with a low-oxygen environment [ 10 ]. In general, heterocysts lack photosystem II activity and ribulose bisphosphate carboxylase, and they cannot photoreduce CO 2 via the reductive pentose phosphate pathway to provide carbon skeletons for assimilation of fixed nitrogen [ 6 , 11 – 13 ].…”

Section: Introductionmentioning

confidence: 99%

“…In general, heterocysts lack photosystem II activity and ribulose bisphosphate carboxylase, and they cannot photoreduce CO 2 via the reductive pentose phosphate pathway to provide carbon skeletons for assimilation of fixed nitrogen [ 6 , 11 – 13 ]. The heterocyst develops a special glycolipid layer that serves as a gas diffusion barrier, and the heterocyst glycolipid layer can be modified in response to the external O2 concentration [ 10 , 14 ]. However, other studies suggested that heterocysts are not the only cells capable of nitrogen fixation in heterocystous cyanobacteria and that vegetative cells can fix molecular nitrogen using another nitrogenase encoded by a homologous gene cluster named as nif2 [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Vegetative cells may perform nitrogen fixation function under nitrogen deprivation in Anabaena sp. strain PCC 7120 based on genome-wide differential expression analysis

Miao

Huang

et al. 2021

PLoS ONE

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Nitrogen assimilation is strictly regulated in cyanobacteria. In an inorganic nitrogen-deficient environment, some vegetative cells of the cyanobacterium Anabaena differentiate into heterocysts. We assessed the photosynthesis and nitrogen-fixing capacities of heterocysts and vegetative cells, respectively, at the transcriptome level. RNA extracted from nitrogen-replete vegetative cells (NVs), nitrogen-deprived vegetative cells (NDVs), and nitrogen-deprived heterocysts (NDHs) in Anabaena sp. strain PCC 7120 was evaluated by transcriptome sequencing. Paired comparisons of NVs vs. NDHs, NVs vs. NDVs, and NDVs vs. NDHs revealed 2,044 differentially expressed genes (DEGs). Kyoto Encyclopedia of Genes and Genomes enrichment analysis of the DEGs showed that carbon fixation in photosynthetic organisms and several nitrogen metabolism-related pathways were significantly enriched. Synthesis of Gvp (Gas vesicle synthesis protein gene) in NVs was blocked by nitrogen deprivation, which may cause Anabaena cells to sink and promote nitrogen fixation under anaerobic conditions; in contrast, heterocysts may perform photosynthesis under nitrogen deprivation conditions, whereas the nitrogen fixation capability of vegetative cells was promoted by nitrogen deprivation. Immunofluorescence analysis of nitrogenase iron protein suggested that the nitrogen fixation capability of vegetative cells was promoted by nitrogen deprivation. Our findings provide insight into the molecular mechanisms underlying nitrogen fixation and photosynthesis in vegetative cells and heterocysts at the transcriptome level. This study provides a foundation for further functional verification of heterocyst growth, differentiation, and water bloom control.

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The effect of oxygen concentration and temperature on nitrogenase activity in the heterocystous cyanobacterium Fischerella sp.

Cited by 34 publications

References 32 publications

Microbial diversity and soil physiochemical characteristic of higher altitude

Microbial diversity and soil physiochemical characteristic of higher altitude

Genetic responses to carbon and nitrogen availability in Anabaena

Vegetative cells may perform nitrogen fixation function under nitrogen deprivation in Anabaena sp. strain PCC 7120 based on genome-wide differential expression analysis

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