scholarly journals A One-Hole Cu4S Cluster with N2O Reductase Activity: A Structural and Functional Model for CuZ*

2016 ◽  
Vol 138 (40) ◽  
pp. 13107-13110 ◽  
Author(s):  
Brittany J. Johnson ◽  
William E. Antholine ◽  
Sergey V. Lindeman ◽  
Michael J. Graham ◽  
Neal P. Mankad
Keyword(s):  
Reductase Activity ◽  
Functional Model ◽  
N2o Reductase

scholarly journals Linked Expressions ofnapandnosGenes in a Bradyrhizobium japonicum Mutant with Increased N2O Reductase Activity

2013 ◽  
Vol 79 (13) ◽  
pp. 4178-4180 ◽  
Author(s):  
Cristina Sánchez ◽  
Manabu Itakura ◽  
Hisayuki Mitsui ◽  
Kiwamu Minamisawa
Keyword(s):  
Nitrate Reductase ◽  
Bradyrhizobium Japonicum ◽  
Enrichment Culture ◽  
Reductase Activity ◽  
Content Type ◽  
Periplasmic Nitrate Reductase ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
N2o Reductase

ABSTRACTTo understand the mechanisms underlying the increased N2O reductase activity in theBradyrhizobium japonicum5M09 mutant from enrichment culture under N2O respiration, we analyzed the expression of genes encoding denitrification reductases and regulators. Our results suggest a common regulation ofnap(encoding periplasmic nitrate reductase) andnos(encoding N2O reductase).

scholarly journals Generation of Bradyrhizobium japonicum Mutants with Increased N2O Reductase Activity by Selection after Introduction of a Mutated dnaQ Gene

2008 ◽  
Vol 74 (23) ◽  
pp. 7258-7264 ◽  
Author(s):  
Manabu Itakura ◽  
Kazufumi Tabata ◽  
Shima Eda ◽  
Hisayuki Mitsui ◽  
Kiriko Murakami ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Bradyrhizobium Japonicum ◽  
Symbiotic Nitrogen Fixation ◽  
Enrichment Culture ◽  
Reductase Activity ◽  
Wild Type ◽  
Epsilon Subunit ◽  
Bacterial Mutants ◽  
N2o Reductase ◽  
Type Strains

ABSTRACT We obtained two beneficial mutants of Bradyrhizobium japonicum USDA110 with increased nitrous oxide (N2O) reductase (N2OR) activity by introducing a plasmid containing a mutated B. japonicum dnaQ gene (pKQ2) and performing enrichment culture under selection pressure for N2O respiration. Mutation of dnaQ, which encodes the epsilon subunit of DNA polymerase III, gives a strong mutator phenotype in Escherichia coli. pKQ2 introduction into B. japonicum USDA110 increased the frequency of occurrence of colonies spontaneously resistant to kanamycin. A series of repeated cultivations of USDA110 with and without pKQ2 was conducted in anaerobic conditions under 5% (vol/vol) or 20% (vol/vol) N2O atmosphere. At the 10th cultivation cycle, cell populations of USDA110(pKQ2) showed higher N2OR activity than the wild-type strains. Four bacterial mutants lacking pKQ2 obtained by plant passage showed 7 to 12 times the N2OR activity of the wild-type USDA110. Although two mutants had a weak or null fix phenotype for symbiotic nitrogen fixation, the remaining two (5M09 and 5M14) had the same symbiotic nitrogen fixation ability and heterotrophic growth in culture as wild-type USDA110.

Ecological and physiological implications of nitrogen oxide reduction pathways on greenhouse gas emissions in agroecosystems

2019 ◽  
Vol 95 (6) ◽  
Author(s):  
Sukhwan Yoon ◽  
Bongkeun Song ◽  
Rebecca L Phillips ◽  
Jin Chang ◽  
Min Joon Song
Keyword(s):  
Reductase Activity ◽  
Ghg Emissions ◽  
Mitigation Strategies ◽  
N2o Emissions ◽  
Oxide Reduction ◽  
N Budget ◽  
Ghg Mitigation ◽  
N Losses ◽  
N2o Production ◽  
N2o Reductase

ABSTRACT Microbial reductive pathways of nitrogen (N) oxides are highly relevant to net emissions of greenhouse gases (GHG) from agroecosystems. Several biotic and abiotic N-oxide reductive pathways influence the N budget and net GHG production in soil. This review summarizes the recent findings of N-oxide reduction pathways and their implications to GHG emissions in agroecosystems and proposes several mitigation strategies. Denitrification is the primary N-oxide reductive pathway that results in direct N2O emissions and fixed N losses, which add to the net carbon footprint. We highlight how dissimilatory nitrate reduction to ammonium (DNRA), an alternative N-oxide reduction pathway, may be used to reduce N2O production and N losses via denitrification. Implications of nosZ abundance and diversity and expressed N2O reductase activity to soil N2O emissions are reviewed with focus on the role of the N2O-reducers as an important N2O sink. Non-prokaryotic N2O sources, e.g. fungal denitrification, codenitrification and chemodenitrification, are also summarized to emphasize their potential significance as modulators of soil N2O emissions. Through the extensive review of these recent scientific advancements, this study posits opportunities for GHG mitigation through manipulation of microbial N-oxide reductive pathways in soil.

Determination of potential N2O-reductase activity in soil

2014 ◽  
Vol 70 ◽  
pp. 205-210 ◽  
Author(s):  
Shuping Qin ◽  
Haijing Yuan ◽  
Chunsheng Hu ◽  
Oene Oenema ◽  
Yuming Zhang ◽  
...  
Keyword(s):  
Reductase Activity ◽  
N2o Reductase

Lamin B receptor: role on chromatin structure, cellular senescence and possibly aging

2020 ◽  
Vol 477 (14) ◽  
pp. 2715-2720
Author(s):  
Susana Castro-Obregón
Keyword(s):  
Cellular Senescence ◽  
Nuclear Membrane ◽  
Chromatin Structure ◽  
Cholesterol Synthesis ◽  
Reductase Activity ◽  
Chimeric Protein ◽  
Nuclear Lamina ◽  
Lamin B ◽  
Inner Nuclear Membrane ◽  
Lamin B Receptor

The nuclear envelope is composed by an outer nuclear membrane and an inner nuclear membrane, which is underlain by the nuclear lamina that provides the nucleus with mechanical strength for maintaining structure and regulates chromatin organization for modulating gene expression and silencing. A layer of heterochromatin is beneath the nuclear lamina, attached by inner nuclear membrane integral proteins such as Lamin B receptor (LBR). LBR is a chimeric protein, having also a sterol reductase activity with which it contributes to cholesterol synthesis. Lukasova et al. showed that when DNA is damaged by ɣ-radiation in cancer cells, LBR is lost causing chromatin structure changes and promoting cellular senescence. Cellular senescence is characterized by terminal cell cycle arrest and the expression and secretion of various growth factors, cytokines, metalloproteinases, etc., collectively known as senescence-associated secretory phenotype (SASP) that cause chronic inflammation and tumor progression when they persist in the tissue. Therefore, it is fundamental to understand the molecular basis for senescence establishment, maintenance and the regulation of SASP. The work of Lukasova et al. contributed to our understanding of cellular senescence establishment and provided the basis that lead to the further discovery that chromatin changes caused by LBR reduction induce an up-regulated expression of SASP factors. LBR dysfunction has relevance in several diseases and possibly in physiological aging. The potential bifunctional role of LBR on cellular senescence establishment, namely its role in chromatin structure together with its enzymatic activity contributing to cholesterol synthesis, provide a new target to develop potential anti-aging therapies.

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