Biochemical characterization of nitrate and nitrite reduction in the wild-type and a nitrate reductase mutant of soybean

The emergence and spread of mutants resistant to bacteriocins would threaten the safety of using bacteriocins as food preservatives. To determine the physiological characteristics of resistant mutants, mutants of Enterococcus faecium resistant to mundticin KS, a class IIa bacteriocin, were isolated. Two types of mutant were found that had different sensitivities to other antimicrobial agents such as nisin (class I) and kanamycin. Both mutants were resistant to mundticin KS even in the absence of Mg2+ ions. The composition of unsaturated fatty acids in the resistant mutants was significantly increased in the presence of mundticin KS. The composition of the phospholipids in the two resistant mutants also differed from those in the wild-type strain. The putative zwitterionic amino-containing phospholipid in both mutants significantly increased, whereas amounts of phosphatidylglycerol and cardiolipin decreased. These changes in membrane structure may influence resistance of enterococci to class IIa and class I bacteriocins.

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Purification and biochemical characterization of simplified eukaryotic nitrate reductase expressed in Pichia pastoris

Protein Expression and Purification ◽

10.1016/j.pep.2004.05.021 ◽

2004 ◽

Vol 37 (1) ◽

pp. 61-71 ◽

Cited By ~ 22

Author(s):

Guillaume G Barbier ◽

Rama C Joshi ◽

Ellen R Campbell ◽

Wilbur H (Bill) Campbell

Keyword(s):

Pichia Pastoris ◽

Nitrate Reductase ◽

Biochemical Characterization

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Nitrate and nitrite reduction by ferrous iron minerals in polluted groundwater: Isotopic characterization of batch experiments

Chemical Geology ◽

10.1016/j.chemgeo.2020.119691 ◽

2020 ◽

Vol 548 ◽

pp. 119691

Author(s):

Rosanna Margalef-Marti ◽

Raúl Carrey ◽

José Antonio Benito ◽

Vicenç Marti ◽

Albert Soler ◽

...

Keyword(s):

Ferrous Iron ◽

Nitrite Reduction ◽

Batch Experiments ◽

Iron Minerals ◽

Isotopic Characterization ◽

Nitrate And Nitrite

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Isolation and Characterization of Mutations in theEscherichia coli Regulatory Protein XapR

Journal of Bacteriology ◽

10.1128/jb.181.14.4397-4403.1999 ◽

1999 ◽

Vol 181 (14) ◽

pp. 4397-4403 ◽

Cited By ~ 22

Author(s):

Casper Jørgensen ◽

Gert Dandanell

Keyword(s):

Amino Acids ◽

Purine Nucleoside Phosphorylase ◽

Mutational Analysis ◽

Regulatory Protein ◽

Three Dimensional ◽

Dimensional Structure ◽

Wild Type ◽

Isolation And Characterization ◽

In The Wild

ABSTRACT In this work, the LysR-type protein XapR has been subjected to a mutational analysis. XapR regulates the expression of xanthosine phosphorylase (XapA), a purine nucleoside phosphorylase inEscherichia coli. In the wild type, full expression of XapA requires both a functional XapR protein and the inducer xanthosine. Here we show that deoxyinosine can also function as an inducer in the wild type, although not to the same extent as xanthosine. We have isolated and characterized in detail the mutants that can be induced by other nucleosides as well as xanthosine. Sequencing of the mutants has revealed that two regions in XapR are important for correct interactions between the inducer and XapR. One region is defined by amino acids 104 and 132, and the other region, containing most of the isolated mutations, is found between amino acids 203 and 210. These regions, when modelled into the three-dimensional structure of CysB from Klebsiella aerogenes, are placed close together and are most probably directly involved in binding the inducer xanthosine.

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Characterization of gamma irradiation-induced mutations in Arabidopsis mutants deficient in non-homologous end joining

Journal of Radiation Research ◽

10.1093/jrr/rraa059 ◽

2020 ◽

Vol 61 (5) ◽

pp. 639-647

Author(s):

Yan Du ◽

Yoshihiro Hase ◽

Katsuya Satoh ◽

Naoya Shikazono

Keyword(s):

Gamma Rays ◽

Wild Type ◽

End Joining ◽

Complex Type ◽

Single Base ◽

In The Wild ◽

Non Homologous End Joining ◽

Dna Ends ◽

Wild Type Control

Abstract To investigate the involvement of the non-homologous end joining (NHEJ) pathway in plant mutagenesis by ionizing radiation, we conducted a genome-wide characterization of the mutations induced by gamma rays in NHEJ-deficient Arabidopsis mutants (AtKu70−/− and AtLig4−/−). Although both mutants were more sensitive to gamma rays than the wild-type control, the AtKu70−/− mutant was slightly more sensitive than the AtLig4−/− mutant. Single-base substitutions (SBSs) were the predominant mutations in the wild-type control, whereas deletions (≥2 bp) and complex-type mutations [i.e. more than two SBSs or short insertion and deletions (InDels) separated by fewer than 10 bp] were frequently induced in the mutants. Single-base deletions were the most frequent deletions in the wild-type control, whereas the most common deletions in the mutants were 11–30 bp. The apparent microhomology at the rejoined sites of deletions peaked at 2 bp in the wild-type control, but was 3–4 bp in the mutants. This suggests the involvement of alternative end joining and single-strand annealing pathways involving increased microhomology for rejoining DNA ends. Complex-type mutations comprising short InDels were frequently detected in the mutants, but not in the wild-type control. Accordingly, NHEJ is more precise than the backup pathways, and is the main pathway for rejoining the broken DNA ends induced by ionizing radiation in plants.

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Biochemical Characterization of Arabidopsis Wild-Type and Mutant Phytochrome B Holoproteins

The Plant Cell ◽

10.2307/3870584 ◽

1997 ◽

Vol 9 (12) ◽

pp. 2271

Author(s):

Tedd D. Elich ◽

Joanne Chory

Keyword(s):

Biochemical Characterization ◽

Phytochrome B ◽

Wild Type

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A composite biochemical system for bacterial nitrate and nitrite assimilation as exemplified by Paracoccus denitrificans

Biochemical Journal ◽

10.1042/bj20101920 ◽

2011 ◽

Vol 435 (3) ◽

pp. 743-753 ◽

Cited By ~ 34

Author(s):

Andrew J. Gates ◽

Victor M. Luque-Almagro ◽

Alan D. Goddard ◽

Stuart J. Ferguson ◽

M. Dolores Roldán ◽

...

Keyword(s):

Nitrate Reductase ◽

Nitrogen Source ◽

Nitrite Reductase ◽

Paracoccus Denitrificans ◽

Gene Clusters ◽

Anion Exchange Chromatography ◽

Exchange Chromatography ◽

Nitrite Reduction ◽

Anaerobic Growth ◽

Nitrate And Nitrite

The denitrifying bacterium Paracoccus denitrificans can grow aerobically or anaerobically using nitrate or nitrite as the sole nitrogen source. The biochemical pathway responsible is expressed from a gene cluster comprising a nitrate/nitrite transporter (NasA), nitrite transporter (NasH), nitrite reductase (NasB), ferredoxin (NasG) and nitrate reductase (NasC). NasB and NasG are essential for growth with nitrate or nitrite as the nitrogen source. NADH serves as the electron donor for nitrate and nitrite reduction, but only NasB has a NADH-oxidizing domain. Nitrate and nitrite reductase activities show the same Km for NADH and can be separated by anion-exchange chromatography, but only fractions containing NasB retain the ability to oxidize NADH. This implies that NasG mediates electron flux from the NADH-oxidizing site in NasB to the sites of nitrate and nitrite reduction in NasC and NasB respectively. Delivery of extracellular nitrate to NasBGC is mediated by NasA, but both NasA and NasH contribute to nitrite uptake. The roles of NasA and NasC can be substituted during anaerobic growth by the biochemically distinct membrane-bound respiratory nitrate reductase (Nar), demonstrating functional overlap. nasG is highly conserved in nitrate/nitrite assimilation gene clusters, which is consistent with a key role for the NasG ferredoxin, as part of a phylogenetically widespread composite nitrate and nitrite reductase system.

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