scholarly journals Cascade Regulation of Dimethyl Sulfoxide Reductase (dor) Gene Expression in the Facultative Phototroph Rhodobacter sphaeroides 2.4.1T

1998 ◽  
Vol 180 (11) ◽  
pp. 2924-2930 ◽  
Author(s):  
Nigel J. Mouncey ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Dimethyl Sulfoxide ◽  
Rhodobacter Sphaeroides ◽  
Wild Type Strain ◽  
Growth Conditions ◽  
Genes Encoding ◽  
Associated Proteins ◽  
In The Wild ◽  
The Media ◽  
Dimethyl Sulfoxide Reductase

ABSTRACT Under anaerobic-dark growth conditions, in the presence of the alternative electron acceptor dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO), Rhodobacter sphaeroides 2.4.1T respires anaerobically using the molybdoenzyme DMSO reductase (DMSOR). Genes encoding DMSOR and associated proteins are encoded by genes of the dor locus. Previously, we demonstrated that the expression of DMSOR is regulated by both the oxygen status of the cell via the FnrL protein and by the presence of DMSO or TMAO, presumably through the DorS-DorR two-component sensor-regulator system. Here we further investigate expression of the dor genes through the use of transcriptional lacZ fusions to the dorS,dorR, and dorC promoters. The expression ofdorC::lacZ was strongly induced by the absence of oxygen and presence of DMSO. In accordance with our previous findings of DMSOR activity,dorC::lacZ expression was reduced by up to one-third when cells were grown photosynthetically in the presence of DMSO with medium or high light, compared to the expression observed after anaerobic-dark growth. The induction ofdorC::lacZ expression in the presence of DMSO was dependent on the DorS and DorR proteins. Expression of thedorS and dorR genes was also induced in the absence of oxygen. In an FnrL mutant,dorS::lacZ expression was not induced when oxygen tensions in the media were lowered, in contrast to what occurred in the wild-type strain. The expression ofdorS::lacZ anddorR::lacZ was dependent on the DorS and DorR proteins themselves, suggesting the importance of autoregulation. These results demonstrate a cascade regulation ofdor gene expression, where the expression of the regulatory proteins DorS and DorR governs the downstream regulation of thedorCBA operon encoding the structural proteins of DMSOR.

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 Redox-Dependent Gene Regulation inRhodobacter sphaeroides 2.4.1T: Effects on Dimethyl Sulfoxide Reductase (dor) Gene Expression

1998 ◽  
Vol 180 (21) ◽  
pp. 5612-5618 ◽  
Author(s):  
Nigel J. Mouncey ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Dimethyl Sulfoxide ◽  
Type Strain ◽  
Wild Type Strain ◽  
Strictly Aerobic ◽  
Wild Type ◽  
Dmso Reductase ◽  
Regulatory Cascade ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACT The ability of Rhodobacter sphaeroides2.4.1T to respire anaerobically with the alternative electron acceptor dimethyl sulfoxide (DMSO) or trimethylamineN-oxide (TMAO) is manifested by the molybdoenzyme DMSO reductase, which is encoded by genes of the dor locus. Previously, we have demonstrated that dor expression is regulated in response to lowered oxygen tensions and the presence of DMSO or TMAO in the growth medium. Several regulatory proteins have been identified as key players in this regulatory cascade: FnrL, DorS-DorR, and DorX-DorY. To further examine the role of redox potentiation in the regulation of dor expression, we measured DMSO reductase synthesis and β-galactosidase activity fromdor::lacZ fusions in strains containing mutations in the redox-active proteins CcoP and RdxB, which have previously been implicated in the generation of a redox signal affecting photosynthesis gene expression. Unlike the wild-type strain, both mutants were able to synthesize DMSO reductase under strictly aerobic conditions, even in the absence of DMSO. When cells were grown photoheterotrophically, dorC::lacZexpression was stimulated by increasing light intensity in the CcoP mutant, whereas it is normally repressed in the wild-type strain under such conditions. Furthermore, the expression of genes encoding the DorS sensor kinase and DorR response regulator proteins was also affected by the ccoP mutation. By using CcoP-DorR and CcoP-DorY double mutants, it was shown that the DorR protein is strictly required for altered dor expression in CcoP mutants. These results further demonstrate a role for redox-generated responses in the expression of genes encoding DMSO reductase in R. sphaeroides and identify the DorS-DorR proteins as a redox-dependent regulatory system controlling dorexpression.

scholarly journals Expression and function of the cdgD gene, encoding a CHASE–PAS-DGC-EAL domain protein, in Azospirillum brasilense

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Soil Conditions ◽  
Wild Type ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Genes Encoding ◽  
In The Wild ◽  
Plant Growth Promoting

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.

scholarly journals Role of Sigma Factors in Controlling Global Gene Expression in Light/Dark Transitions in the Cyanobacterium Synechocystis sp. Strain PCC 6803

2007 ◽  
Vol 189 (21) ◽  
pp. 7829-7840 ◽  
Author(s):  
Tina C. Summerfield ◽  
Louis A. Sherman
Keyword(s):  
Gene Expression ◽  
Global Gene Expression ◽  
Growth Conditions ◽  
Day Length ◽  
Regulation Of Transcription ◽  
Wild Type ◽  
Protein Levels ◽  
In The Wild ◽  
Altered Gene ◽  
Pcc 6803

ABSTRACT We report on differential gene expression in the cyanobacterium Synechocystis sp. strain PCC 6803 after light-dark transitions in wild-type, ΔsigB, and ΔsigD strains. We also studied the effect of day length in the presence of glucose on a ΔsigB ΔsigE mutant. Our results indicated that the absence of SigB or SigD predominately altered gene expression in the dark or in the light, respectively. In the light, approximately 350 genes displayed transcript levels in the ΔsigD strain that were different from those of the wild type, with over 200 of these up-regulated in the mutant. In the dark, removal of SigB altered more than 150 genes, and the levels of 136 of these were increased in the mutant compared to those in the wild type. The removal of both SigB and SigE had a major impact on gene expression under mixotrophic growth conditions and resulted in the inability of cells to grow in the presence of glucose with 8-h light and 16-h dark cycles. Our results indicated the importance of group II σ factors in the global regulation of transcription in this organism and are best explained by using the σ cycle paradigm with the stochastic release model described previously (R. A. Mooney, S. A. Darst, and R. Landick, Mol. Cell 20:335-345, 2005). We combined our results with the total protein levels of the σ factors in the light and dark as calculated previously (S. Imamura, S. Yoshihara, S. Nakano, N. Shiozaki, A. Yamada, K. Tanaka, H. Takahashi, M. Asayama, and M. Shirai, J. Mol. Biol. 325:857-872, 2003; S. Imamura, M. Asayama, H. Takahashi, K. Tanaka, H. Takahashi, and M. Shirai, FEBS Lett. 554:357-362, 2003). Thus, we concluded that the control of global transcription is based on the amount of the various σ factors present and able to bind RNA polymerase.

Amperometric dimethyl sulfoxide sensor using dimethyl sulfoxide reductase from Rhodobacter sphaeroides

2003 ◽  
Vol 18 (5-6) ◽  
pp. 735-739 ◽  
Author(s):  
Mitsuru Abo ◽  
Yuki Ogasawara ◽  
Yoshikiyo Tanaka ◽  
Akira Okubo ◽  
Sunao Yamazaki
Keyword(s):  
Dimethyl Sulfoxide ◽  
Rhodobacter Sphaeroides ◽  
Dimethyl Sulfoxide Reductase

scholarly journals Insights into an alternative pathway for glycerol metabolism in a glycerol kinase deficientPseudomonas putidaKT2440

2019 ◽  
Author(s):  
Meg Walsh ◽  
William Casey ◽  
Shane T. Kenny ◽  
Tanja Narancic ◽  
Lars M. Blank ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Alternative Pathway ◽  
Glycerol Kinase ◽  
Glycerol Metabolism ◽  
Wild Type ◽  
Short Chain Length ◽  
Genes Encoding ◽  
In The Wild

AbstractPseudomonas putidaKT2440 is known to metabolise glycerol via glycerol-3-phosphate using glycerol kinase an enzyme previously described as critical for glycerol metabolism (1). However, when glycerol kinase was knocked out inP. putidaKT2440 it retained the ability to use glycerol as the sole carbon source, albeit with a much-extended lag period and 2 fold lower final biomass compared to the wild type strain. A metabolomic study identified glycerate as a major and the most abundant intermediate in glycerol metabolism in this mutated strain with levels 21-fold higher than wild type. Erythrose-4-phosphate was detected in the mutant strain, but not in the wild type strain. Glyceraldehyde and glycraldehyde-3-phosphate were detected at similar levels in the mutant strain and the wild type. Transcriptomic studies identified 191 genes that were more than 2-fold upregulated in the mutant compared to the wild type and 175 that were down regulated. The genes involved in short chain length fatty acid metabolism were highly upregulated in the mutant strain. The genes encoding 3-hydroxybutyrate dehydrogenase were 5.8-fold upregulated and thus the gene was cloned, expressed and purified to reveal it can act on glyceraldehyde but not glycerol as a substrate.

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