Agrobacterium fabrum C58 involved nitrate reductase NapA and antisense RNA NorR to denitrify

2020 ◽  
Vol 97 (1) ◽  
Author(s):  
Solène Lecomte ◽  
Xavier Nesme ◽  
Théophile Franzino ◽  
Camille Villard ◽  
Mariane Pivard ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Small Rna ◽  
Nitrate Reduction ◽  
Antisense Rna ◽  
Root Colonization ◽  
N2o Emission ◽  
Positive Role ◽  
N2o Production ◽  
Denitrification Genes

ABSTRACT Agrobacterium fabrum C58 is a plant-associated bacterium that is able to denitrify under anoxic conditions. The cluster of denitrification genes harbored by this strain has been well characterized. It includes nir and nor operons encoding nitrite and nitric oxide reductases, respectively. However, the reductase involved in nitrate reduction has not yet been studied and little information is available on denitrification regulators in A. fabrum C58. In this study, we aimed to (i) characterize the nitrate reductase, (ii) determine its role in A. fabrum C58 fitness and root colonization and (ii) reveal the contribution of small RNA on denitrification regulation. By constructing a mutant strain defective for napA, we demonstrated that the reduction of nitrate to nitrite was catalyzed by the periplasmic nitrate reductase, NapA. We evidenced a positive role of NapA in A. fabrum C58 fitness and suggested that A. fabrum C58 is able to use components exuded by plant roots to respire anaerobically. Here, we showed that NorR small RNA increased the level of norCBQ mRNA and a decrease of NorR is correlated with a decrease in N2O emission. Together, our results underscore the importance of understanding the denitrification pathway at the strain level in order to develop strategies to mitigate N2O production at the microbial community level.

scholarly journals The Periplasmic Nitrate Reductase inPseudomonas sp. Strain G-179 Catalyzes the First Step of Denitrification

1999 ◽  
Vol 181 (9) ◽  
pp. 2802-2806 ◽  
Author(s):  
Laura Bedzyk ◽  
Tao Wang ◽  
Rick W. Ye
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Primary Role ◽  
Anaerobic Conditions ◽  
It Use ◽  
Alternative Substrate ◽  
Periplasmic Nitrate Reductase ◽  
Reduction Activity ◽  
Membrane Bound

ABSTRACT Both membrane-bound and periplasmic nitrate reductases have been found in denitrifying bacteria. Yet the role of periplasmic nitrate reductase in denitrification has not been clearly defined. To analyze the function of the periplasmic nitrate reductase inPseudomonas sp. strain G-179, the nap gene cluster was identified and found to be linked to genes involved in reduction of nitrite and nitric oxide and anaerobic heme biosynthesis. Mutation in the nap region rendered the cells incapable of growing under anaerobic conditions with nitrate as the alternative electron acceptor. No nitrate reduction activity was detected in the Nap− mutant, but that activity could be restored by complementation with the nap region. Unlike the membrane-bound nitrate reductase, the nitrate reduction activity in strain G-179 was not inhibited by a low concentration of azide. Nor could it use NADH as the electron donor to reduce nitrate or use chlorate as the alternative substrate. These results suggest that the periplasmic nitrate reductase in this strain plays a primary role in dissimilatory nitrate reduction.

scholarly journals Genetic evidence reveals the indispensable role of the rseC gene for autotrophy and the importance of a functional electron balance for nitrate reduction in Clostridium ljungdahlii

2021 ◽  
Author(s):  
Christian-Marco Klask ◽  
Benedikt Jäger ◽  
Largus T Angenent ◽  
Bastian Molitor
Keyword(s):  
Nitrate Reductase ◽  
Gene Cluster ◽  
Nitrate Reduction ◽  
Transcriptional Repression ◽  
Cellular Growth ◽  
Deletion Strain ◽  
Clostridium Ljungdahlii ◽  
Acetogenic Bacteria ◽  
Energy Limitation

For Clostridium ljungdahlii, the RNF complex plays a key role for energy conversion from gaseous substrates such as hydrogen and carbon dioxide. In a previous study, a disruption of RNF-complex genes led to the loss of autotrophy, while heterotrophy was still possible via glycolysis. Furthermore, it was shown that the energy limitation during autotrophy could be lifted by nitrate supplementation, which resulted in an elevated cellular growth and ATP yield. Here, we used CRISPR-Cas12a to delete: 1) the RNF complex-encoding gene cluster rnfCDGEAB; 2) the putative RNF regulator gene rseC; and 3) a gene cluster that encodes for a putative nitrate reductase. The deletion of either rnfCDGEAB or rseC resulted in a complete loss of autotrophy, which could be restored by plasmid-based complementation of the deleted genes. We observed a transcriptional repression of the RNF-gene cluster in the rseC-deletion strain during autotrophy and investigated the distribution of the rseC gene among acetogenic bacteria. To examine nitrate reduction and its connection to the RNF complex, we compared autotrophic and heterotrophic growth of our three deletion strains with either ammonium or nitrate. The rnfCDGEAB- and rseC-deletion strains failed to reduce nitrate as a metabolic activity in non-growing cultures during autotrophy but not during heterotrophy. In contrast, the nitrate reductase deletion strain was able to grow in all tested conditions but lost the ability to reduce nitrate. Our findings highlight the important role of the rseC gene for autotrophy and contribute to understand the connection of nitrate reduction to energy metabolism.

Are Three Items Sufficient to Measure Sense of Coherence?

2018 ◽  
Vol 34 (4) ◽  
pp. 229-237 ◽  
Author(s):  
Francesca Chiesi ◽  
Andrea Bonacchi ◽  
Caterina Primi ◽  
Alessandro Toccafondi ◽  
Guido Miccinesi
Keyword(s):  
Sense Of Coherence ◽  
Convergent Validity ◽  
Clinical Sample ◽  
Clinical Samples ◽  
Depression Symptoms ◽  
Time Saving ◽  
Positive Role ◽  
Patients With Cancer ◽  
Measure Sense

Abstract. The present study aimed at evaluating if the three-item sense of coherence (SOC) scale developed by Lundberg and Nystrom Peck (1995) can be effectively used for research purpose in both nonclinical and clinical samples. To provide evidence that it represents adequately the measured construct we tested its validity in a nonclinical (N = 658) and clinical sample (N = 764 patients with cancer). Results obtained in the nonclinical sample attested a positive relation of SOC – as measured by the three-item SOC scale – with Antonovsky’s 13-item and 29-item SOC scales (convergent validity), and with dispositional optimism, sense of mastery, anxiety, and depression symptoms (concurrent validity). Results obtained in the clinical sample confirmed the criterion validity of the scale attesting the positive role of SOC – as measured by the three-item SOC scale – on the person’s capacity to respond to illness and treatment. The current study provides evidence that the three-item SOC scale is a valid, low-loading, and time-saving instrument for research purposes on large sample.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

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