scholarly journals Overproduction of the Flv3B flavodiiron, enhances the photobiological hydrogen production by the nitrogen-fixing cyanobacterium Nostoc PCC 7120

2020 ◽  
Author(s):  
Baptiste Roumezi ◽  
Luisana Avilan ◽  
Véronique Risoul ◽  
Myriam Brugna ◽  
Sophie Rabouille ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Clean Energy ◽  
Growth Conditions ◽  
Gene Encoding ◽  
Promising Alternative ◽  
Genes Encoding ◽  
Photosynthetic Microorganisms ◽  
Pcc 7120 ◽  
The Impact ◽  
Phototrophic Growth

Abstract Background: The ability of some photosynthetic microorganisms, particularly cyanobacteria and microalgae, to produce hydrogen (H2) is a promising alternative for renewable, clean-energy production. However, the most recent, related studies point out that much improvement is needed for sustainable cyanobacterial-based H2 production to become economically viable. In this study, we investigated the impact of induced O2-consumption on H2 photoproduction yields in the heterocyte-forming, N2-fixing cyanobacterium Nostoc PCC7120. Results: The flv3B gene, encoding a flavodiiron protein naturally expressed in Nostoc heterocytes, was overexpressed. Under aerobic and phototrophic growth conditions, the recombinant strain displayed a significantly higher H2 production than the wild type. Nitrogenase activity assays indicated that flv3B overexpression did not enhance the nitrogen fixation rates. Interestingly, the transcription of the hox genes, encoding the NiFe Hox hydrogenase, was significantly elevated, as shown by the quantitative RT-PCR analyses. Conclusion: We conclude that the overproduced Flv3B protein might have enhanced O2-consumption, thus creating conditions inducing hox genes and facilitating H2 production. The present study clearly demonstrates the potential to use metabolic engineered cyanobacteria for photosynthesis driven H2 production.

scholarly journals Overproduction of the Flv3B flavodiiron, enhances the photobiological hydrogen production by the nitrogen-fixing cyanobacterium Nostoc PCC 7120

2019 ◽  
Author(s):  
Baptiste Roumezi ◽  
Luisana Avilan ◽  
Véronique Risoul ◽  
Myriam Brugna ◽  
Sophie Rabouille ◽  
...  
Keyword(s):  
Hox Genes ◽  
Nitrogenase Activity ◽  
Clean Energy ◽  
Gene Encoding ◽  
Promising Alternative ◽  
Genes Encoding ◽  
Photosynthetic Microorganisms ◽  
Pcc 7120 ◽  
The Impact ◽  
Overexpressing Strain

Abstract Background: The ability of some photosynthetic microorganisms, particularly cyanobacteria and microalgae, to produce hydrogen (H 2 ) is a promising alternative for renewable, clean-energy production. However, studies of the topic in the last decade have shown that much improvement is needed before sustainable cyanobacterial-based H 2 production becomes economically viable. In this study, we investigated the impact of inducing O 2 -consumption to enhance H 2 photoproduction yields in the heterocyst-forming, N 2 -fixing cyanobacterium Nostoc PCC7120. Results: The flv3B gene, encoding a flavodiiron protein naturally expressed in the heterocyst of Nostoc, was overexpressed. Compared to the wild type, the recombinant strain obtained displayed a significantly higher H 2 production under aerobic growth and phototrophic conditions. Nitrogenase activity assays indicated that flv3B overexpression did not increase the nitrogen fixation rates. On the other hand, quantitative RT-PCR experiments showed that the transcription of the hox genes, encoding the NiFe Hox hydrogenase was greatly elevated in the flv3B overexpressing strain. Conclusion: We conclude that the overproduced Flv3B protein might have enhanced O 2 -consumption, thus creating conditions inducing hox genes and facilitating H 2 production. The present study clearly demonstrates the potential to use metabolic engineered cyanobacteria for photosynthesis driven H 2 production.

scholarly journals Colocation of Genes Encoding a tRNA-mRNA Hybrid and a Putative Signaling Peptide on Complementary Strands in the Genome of the Hyperthermophilic Bacterium Thermotoga maritima

2006 ◽  
Vol 188 (19) ◽  
pp. 6802-6807 ◽  
Author(s):  
Clemente I. Montero ◽  
Derrick L. Lewis ◽  
Matthew R. Johnson ◽  
Shannon B. Conners ◽  
Elizabeth A. Nance ◽  
...  
Keyword(s):  
Thermotoga Maritima ◽  
Normal Growth ◽  
Growth Conditions ◽  
Open Reading Frames ◽  
Transcriptional Responses ◽  
Gene Encoding ◽  
Hyperthermophilic Bacterium ◽  
Genes Encoding ◽  
Original Genome ◽  
Opposite Strand

ABSTRACT In the genome of the hyperthermophilic bacterium Thermotoga maritima, TM0504 encodes a putative signaling peptide implicated in population density-dependent exopolysaccharide formation. Although not noted in the original genome annotation, TM0504 was found to colocate, on the opposite strand, with the gene encoding ssrA, a hybrid of tRNA and mRNA (tmRNA), which is involved in a trans-translation process related to ribosome rescue and is ubiquitous in bacteria. Specific DNA probes were designed and used in real-time PCR assays to follow the separate transcriptional responses of the colocated open reading frames (ORFs) during transition from exponential to stationary phase, chloramphenicol challenge, and syntrophic coculture with Methanococcus jannaschii. TM0504 transcription did not vary under normal growth conditions. Transcription of the tmRNA gene, however, was significantly up-regulated during chloramphenicol challenge and in T. maritima bound in exopolysaccharide aggregates during methanogenic coculture. The significance of the colocation of ORFs encoding a putative signaling peptide and tmRNA in T. maritima is intriguing, since this overlapping arrangement (tmRNA associated with putative small ORFs) was found to be conserved in at least 181 bacterial genomes sequenced to date. Whether peptides related to TM0504 in other bacteria play a role in quorum sensing is not yet known, but their ubiquitous colocalization with respect to tmRNA merits further examination.

scholarly journals Optimal Scheduling of Campus Microgrid Considering the Electric Vehicle Integration in Smart Grid

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7133
Author(s):  
Tehreem Nasir ◽  
Safdar Raza ◽  
Muhammad Abrar ◽  
Hafiz Abd ul Muqeet ◽  
Harun Jamil ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Power Supply ◽  
Linear Optimization ◽  
Clean Energy ◽  
High Energy ◽  
Energy Resources ◽  
Pv System ◽  
Promising Alternative ◽  
Continuous Power ◽  
The Impact

High energy consumption, rising environmental concerns and depleting fossil fuels demand an increase in clean energy production. The enhanced resiliency, efficiency and reliability offered by microgrids with distributed energy resources (DERs) have shown to be a promising alternative to the conventional grid system. Large-sized commercial customers like institutional complexes have put significant efforts to promote sustainability by establishing renewable energy systems at university campuses. This paper proposes the integration of a photovoltaic (PV) system, energy storage system (ESS) and electric vehicles (EV) at a University campus. An optimal energy management system (EMS) is proposed to optimally dispatch the energy from available energy resources. The problem is mapped in a Linear optimization problem and simulations are carried out in MATLAB. Simulation results showed that the proposed EMS ensures the continuous power supply and decreases the energy consumption cost by nearly 45%. The impact of EV as a storage tool is also observed. EVs acting as a source of energy reduced the energy cost by 45.58% and as a load by 19.33%. The impact on the cost for continuous power supply in case of a power outage is also analyzed.

Ethanol Logistics for Fuel Cells Applications in Brazil

2008 ◽  
Author(s):  
Egberto Gomes Franco ◽  
Paulo Lucas Dantas Filho ◽  
Flavio Taioli ◽  
Carlos Eduardo Rollo Ribeiro ◽  
Geraldo Francisco Burani
Keyword(s):  
Fuel Cells ◽  
Natural Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Clean Energy ◽  
Energy Generation ◽  
Promising Alternative ◽  
Remote Areas ◽  
Global Player ◽  
The Impact

One important element to reduce the impact of the present economic development model in nature is the energy generation. The need for more efficient sources of energy is evident, as the world relies on fossil fuel sources that become scarcer and expensive. Furthermore, imposes the use of clean fuels, like hydrogen and renewable primary fuels in large scale. The fuel cells technology have shown to be an interesting and very promising alternative, among others, to solve the problem of generating clean energy with high efficiency, using hydrogen, natural gas and ethanol. Hydrogen production from ethanol is an attractive technique, due to it renewable source, allowing clean energy generation. To permit that, the logistics of ethanol plays an essential role, allowing easy and full access to this fuel also in remote areas. In this article, we identify the necessary infra-structure to lead Brazil as a global player in the Hydrogen Economy. The costs of natural gas and ethanol as “carriers” were identified, pointing out weaknesses and strongest points of these primary fuels. The combination of these two technologies could drive Brazil to a clean and renewable energy source, mainly in remote areas.

scholarly journals Alr0397 Is an Outer Membrane Transporter for the Siderophore Schizokinen in Anabaena sp. Strain PCC 7120

2008 ◽  
Vol 190 (22) ◽  
pp. 7500-7507 ◽  
Author(s):  
Kerstin Nicolaisen ◽  
Suncana Moslavac ◽  
Anastazia Samborski ◽  
Marianne Valdebenito ◽  
Klaus Hantke ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Iron Homeostasis ◽  
Iron Starvation ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Outer Membrane Transporter ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Outer Membrane Transporters

ABSTRACT Iron uptake in proteobacteria by TonB-dependent outer membrane transporters represents a well-explored subject. In contrast, the same process has been scarcely investigated in cyanobacteria. The heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 is known to secrete the siderophore schizokinen, but its transport system has remained unidentified. Inspection of the genome of strain PCC 7120 shows that only one gene encoding a putative TonB-dependent iron transporter, namely alr0397, is positioned close to genes encoding enzymes involved in the biosynthesis of a hydroxamate siderophore. The expression of alr0397, which encodes an outer membrane protein, was elevated under iron-limited conditions. Inactivation of this gene caused a moderate phenotype of iron starvation in the mutant cells. The characterization of the mutant strain showed that Alr0397 is a TonB-dependent schizokinen transporter (SchT) of the outer membrane and that alr0397 expression and schizokinen production are regulated by the iron homeostasis of the cell.

scholarly journals Phenotype inference in an Escherichia coli strain panel

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Marco Galardini ◽  
Alexandra Koumoutsi ◽  
Lucia Herrera-Dominguez ◽  
Juan Antonio Cordero Varela ◽  
Anja Telzerow ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Association Studies ◽  
Growth Conditions ◽  
Coli Strain ◽  
Genome Wide Association Studies ◽  
Loss Of Function ◽  
Promising Alternative ◽  
Genetic Interventions ◽  
K 12 ◽  
The Impact

Understanding how genetic variation contributes to phenotypic differences is a fundamental question in biology. Combining high-throughput gene function assays with mechanistic models of the impact of genetic variants is a promising alternative to genome-wide association studies. Here we have assembled a large panel of 696 Escherichia coli strains, which we have genotyped and measured their phenotypic profile across 214 growth conditions. We integrated variant effect predictors to derive gene-level probabilities of loss of function for every gene across all strains. Finally, we combined these probabilities with information on conditional gene essentiality in the reference K-12 strain to compute the growth defects of each strain. Not only could we reliably predict these defects in up to 38% of tested conditions, but we could also directly identify the causal variants that were validated through complementation assays. Our work demonstrates the power of forward predictive models and the possibility of precision genetic interventions.

scholarly journals Two Genes Encoding Protein Kinases of the HstK Family Are Involved in Synthesis of the Minor Heterocyst-Specific Glycolipid in the Cyanobacterium Anabaena sp. Strain PCC 7120

2007 ◽  
Vol 189 (14) ◽  
pp. 5075-5081 ◽  
Author(s):  
Lei Shi ◽  
Jian-Hong Li ◽  
Yong Cheng ◽  
Li Wang ◽  
Wen-Li Chen ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Early Stage ◽  
Kinase Domain ◽  
Filamentous Cyanobacterium ◽  
Regulatory Pathways ◽  
Genes Encoding ◽  
Putative Transcription Factor ◽  
Oxygen Sensitive ◽  
Cyanobacterium Anabaena ◽  
Pcc 7120

ABSTRACT The filamentous cyanobacterium Anabaena sp. strain PCC 7120 can fix N2 under oxic conditions, and the activity of nitrogen fixation occurs exclusively in heterocysts, cells differentiated from vegetative cells in response to a limitation of a combined-nitrogen source in the growth medium. At the late stages of heterocyst differentiation, an envelope layer composed of two glycolipids is formed to limit the entry of oxygen so that the oxygen-sensitive nitrogenase can function. The genome of Anabaena sp. strain PCC 7120 possesses a family of 13 genes (the hstK family), all encoding proteins with a putative Ser/Thr kinase domain at their N termini and a His-kinase domain at their C termini. In this study, we showed that the double mutant D4.3 strain, in which two members of this gene family, pkn44 (all1625) and pkn30 (all3691), were both inactivated, failed to fix N2 in the presence of oxygen (Fox−). In an environment without oxygen, a low level of nitrogenase activity was detectable (Fix+). Heterocyst development in the mutant D4.3 was delayed by 24 h and arrested at a relatively early stage without the formation of the glycolipid layer (Hgl−). Only the minor species of the two heterocyst-specific glycolipids (HGLs) was missing in the mutant. We propose that DevH, a putative transcription factor, coordinates the synthesis of both HGLs, while Pkn44/Pkn30 and the previously characterized PrpJ may represent two distinct regulatory pathways involved in the synthesis of the minor HGL and the major HGL, respectively.

scholarly journals Oxygen Regulation of the ccoN Gene Encoding a Component of the cbb3 Oxidase inRhodobacter sphaeroides 2.4.1T: Involvement of the FnrL Protein

1998 ◽  
Vol 180 (8) ◽  
pp. 2228-2231 ◽  
Author(s):  
Nigel J. Mouncey ◽  
Samuel Kaplan
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Type Strain ◽  
Wild Type Strain ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Wild Type ◽  
Transcriptional Fusion ◽  
Gene Encoding ◽  
Genes Encoding ◽  
In The Wild

ABSTRACT The ccoNOQP gene cluster of Rhodobacter sphaeroides 2.4.1T encodes acbb 3 cytochrome oxidase which is utilized in oxygen-limited conditions for aerobic respiration. The β-galactosidase activity of accoN::lacZ transcriptional fusion was low under high (30%)-oxygen and anaerobic growth conditions. Maximal ccoN::lacZexpression was observed when the oxygen concentration was lowered to 2%. In an FnrL mutant,ccoN::lacZ expression was significantly lower than in the wild-type strain, suggesting that FnrL is a positive regulator of genes encoding thecbb 3 oxidase.

scholarly journals Consumption of Enriched Yogurt with PAF Inhibitors from Olive Pomace Affects the Major Enzymes of PAF Metabolism: A Randomized, Double Blind, Three Arm Trial

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 801
Author(s):  
Maria Detopoulou ◽  
Agathi Ntzouvani ◽  
Filio Petsini ◽  
Labrini Gavriil ◽  
Εlizabeth Fragopoulou ◽  
...  
Keyword(s):  
Platelet Activating Factor ◽  
Lipid Mediator ◽  
Olive Pomace ◽  
Double Blind ◽  
Promising Alternative ◽  
Catabolic Enzymes ◽  
Platelet Activating Factor Acetylhydrolase ◽  
The Impact ◽  
By Products ◽  
Apparently Healthy

Platelet-activating factor (PAF), a proinflammatory lipid mediator, plays a crucial role in the formation of the atherosclerotic plaque. Therefore, the inhibition of endothelium inflammation by nutraceuticals, such as PAF inhibitors, is a promising alternative for preventing cardiovascular diseases. The aim of the present study was to evaluate the impact of a new functional yogurt enriched with PAF inhibitors of natural origin from olive oil by-products on PAF metabolism. Ninety-two apparently healthy, but mainly overweight volunteers (35–65 years) were randomly allocated into three groups by block-randomization. The activities of PAF’s biosynthetic and catabolic enzymes were measured, specifically two isoforms of acetyl-CoA:lyso-PAF acetyltransferase (LPCATs), cytidine 5′-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT) and two isoforms of platelet activating factor acetylhydrolase in leucocytes (PAF-AH) and plasma (lipoprotein associated phospholipase-A2, LpPLA2). The intake of the enriched yogurt resulted in reduced PAF-CPT and LpPLA2 activities. No difference was observed in the activities of the two isoforms of lyso PAF-AT. In conclusion, intake of yogurt enriched in PAF inhibitors could favorably modulate PAF biosynthetic and catabolic pathways.

scholarly journals A Metzincin and TIMP-Like Protein Pair of a Phage Origin Sensitize Listeria monocytogenes to Phage Lysins and Other Cell Wall Targeting Agents

2021 ◽  
Vol 9 (6) ◽  
pp. 1323
Author(s):  
Etai Boichis ◽  
Nadejda Sigal ◽  
Ilya Borovok ◽  
Anat A. Herskovits
Keyword(s):  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Mammalian Cells ◽  
Protein Pair ◽  
Growth Conditions ◽  
Wall Structure ◽  
Antibiotic Resistant ◽  
Extracellular Milieu ◽  
Virion Release ◽  
Genes Encoding

Infection of mammalian cells by Listeria monocytogenes (Lm) was shown to be facilitated by its phage elements. In a search for additional phage remnants that play a role in Lm’s lifecycle, we identified a conserved locus containing two XRE regulators and a pair of genes encoding a secreted metzincin protease and a lipoprotein structurally similar to a TIMP-family metzincin inhibitor. We found that the XRE regulators act as a classic CI/Cro regulatory switch that regulates the expression of the metzincin and TIMP-like genes under intracellular growth conditions. We established that when these genes are expressed, their products alter Lm morphology and increase its sensitivity to phage mediated lysis, thereby enhancing virion release. Expression of these proteins also sensitized the bacteria to cell wall targeting compounds, implying that they modulate the cell wall structure. Our data indicate that these effects are mediated by the cleavage of the TIMP-like protein by the metzincin, and its subsequent release to the extracellular milieu. While the importance of this locus to Lm pathogenicity remains unclear, the observation that this phage-associated protein pair act upon the bacterial cell wall may hold promise in the field of antibiotic potentiation to combat antibiotic resistant bacterial pathogens.

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