Characterization of transcription organization and analysis of unique expression patterns of an alkyl hydroperoxide reductase C gene (ahpC) and the peroxide regulator operon ahpF-oxyR-orfX from Xanthomonas campestris pv. phaseoli.

ABSTRACT We have isolated a new organic hydroperoxide resistance (ohr) gene from Xanthomonas campestris pv. phaseoli. This was done by complementation of anEscherichia coli alkyl hydroperoxide reductase mutant with an organic hydroperoxide-hypersensitive phenotype. ohrencodes a 14.5-kDa protein. Its amino acid sequence shows high homology with several proteins of unknown function. An ohr mutant was subsequently constructed, and it showed increased sensitivity to both growth-inhibitory and killing concentrations of organic hydroperoxides but not to either H2O2 or superoxide generators. No alterations in sensitivity to other oxidants or stresses were observed in the mutant. ohr had interesting expression patterns in response to low concentrations of oxidants. It was highly induced by organic hydroperoxides, weakly induced by H2O2, and not induced at all by a superoxide generator. The novel regulation pattern of ohrsuggests the existence of a second organic hydroperoxide-inducible system that differs from the global peroxide regulator system, OxyR. Expression of ohr in various bacteria tested conferred increased resistance totert-butyl hydroperoxide killing, but this was not so for wild-type Xanthomonas strains. The organic hydroperoxide hypersensitivity of ohr mutants could be fully complemented by expression of ohr or a combination of ahpC and ahpF and could be partially complemented by expression ahpC alone. The data suggested that Ohr was a new type of organic hydroperoxide detoxification protein.

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In vitro and in vivo characterization of alkyl hydroperoxide reductase mutant strains of Helicobacter hepaticus

Biochimica et Biophysica Acta (BBA) - General Subjects ◽

10.1016/j.bbagen.2006.09.022 ◽

2007 ◽

Vol 1770 (2) ◽

pp. 257-265 ◽

Cited By ~ 10

Author(s):

Nalini S. Mehta ◽

Stéphane L. Benoit ◽

Jagannatha Mysore ◽

Robert J. Maier

Keyword(s):

Helicobacter Hepaticus ◽

Alkyl Hydroperoxide Reductase ◽

Alkyl Hydroperoxide ◽

Mutant Strains ◽

In Vivo Characterization

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A Suppressor of the Menadione-Hypersensitive Phenotype of a Xanthomonas campestris pv. phaseoli oxyR Mutant Reveals a Novel Mechanism of Toxicity and the Protective Role of Alkyl Hydroperoxide Reductase

Journal of Bacteriology ◽

10.1128/jb.185.5.1734-1738.2003 ◽

2003 ◽

Vol 185 (5) ◽

pp. 1734-1738 ◽

Cited By ~ 8

Author(s):

Paiboon Vattanaviboon ◽

Wirongrong Whangsuk ◽

Skorn Mongkolsuk

Keyword(s):

Xanthomonas Campestris ◽

Fold Increase ◽

Organic Peroxide ◽

Protective Role ◽

Alkyl Hydroperoxide Reductase ◽

Stress Protection ◽

Alkyl Hydroperoxide ◽

Increased Sensitivity ◽

Scavenging Enzymes ◽

Moderately Resistant

ABSTRACT We isolated menadione-resistant mutants of Xanthomonas campestris pv. phaseoli oxyR (oxyRXp ). The oxyRR2 Xp mutant was hyperresistant to the superoxide generators menadione and plumbagin and was moderately resistant to H2O2 and tert-butyl hydroperoxide. Analysis of enzymes involved in oxidative-stress protection in the oxyRR2 Xp mutant revealed a >10-fold increase in AhpC and AhpF levels, while the levels of superoxide dismutase (SOD), catalase, and the organic hydroperoxide resistance protein (Ohr) were not significantly altered. Inactivation of ahpC in the oxyRR2 Xp mutant resulted in increased sensitivity to menadione killing. Moreover, high levels of expression of cloned ahpC and ahpF in the oxyRXp mutant complemented the menadione hypersensitivity phenotype. High levels of other oxidant-scavenging enzymes such as catalase and SOD did not protect the cells from menadione toxicity. These data strongly suggest that the toxicity of superoxide generators could be mediated via organic peroxide production and that alkyl hydroperoxide reductase has an important novel function in the protection against the toxicity of these compounds in X. campestris.

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Characterization of the SIRT genes and their distinct expression patterns in Manila clams (Ruditapes philippinarum) exposed to air

Meta Gene ◽

10.1016/j.mgene.2021.100892 ◽

2021 ◽

Vol 28 ◽

pp. 100892

Author(s):

Jingtian Wang ◽

He Zhang ◽

Shuang Xu ◽

Ze Liu ◽

Lu Yang ◽

...

Keyword(s):

Expression Patterns ◽

Ruditapes Philippinarum

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Identification and Characterization of Abiotic Stress Responsive CBL-CIPK Family Genes in Medicago

International Journal of Molecular Sciences ◽

10.3390/ijms22094634 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4634

Author(s):

Wenxuan Du ◽

Junfeng Yang ◽

Lin Ma ◽

Qian Su ◽

Yongzhen Pang

Keyword(s):

Abiotic Stress ◽

Abiotic Stresses ◽

Expression Patterns ◽

Interacting Protein ◽

Forage Crop ◽

Cis Acting ◽

Protein Motifs ◽

Plant Signal Transduction ◽

Identification And Characterization

The calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) play important roles in plant signal transduction and response to abiotic stress. Plants of Medicago genus contain many important forages, and their growth is often affected by a variety of abiotic stresses. However, studies on the CBL and CIPK family member and their function are rare in Medicago. In this study, a total of 23 CBL and 58 CIPK genes were identified from the genome of Medicago sativa as an important forage crop, and Medicaog truncatula as the model plant. Phylogenetic analysis suggested that these CBL and CIPK genes could be classified into five and seven groups, respectively. Moreover, these genes/proteins showed diverse exon-intron organizations, architectures of conserved protein motifs. Many stress-related cis-acting elements were found in their promoter region. In addition, transcriptional analyses showed that these CBL and CIPK genes exhibited distinct expression patterns in various tissues, and in response to drought, salt, and abscisic acid treatments. In particular, the expression levels of MtCIPK2 (MsCIPK3), MtCIPK17 (MsCIPK11), and MtCIPK18 (MsCIPK12) were significantly increased under PEG, NaCl, and ABA treatments. Collectively, our study suggested that CBL and CIPK genes play crucial roles in response to various abiotic stresses in Medicago.

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