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 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 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.

scholarly journals Nitrite and Nitrous Oxide Reductase Regulation by Nitrogen Oxides in Rhodobacter sphaeroides f. sp.denitrificans IL106

1999 ◽  
Vol 181 (19) ◽  
pp. 6028-6032 ◽  
Author(s):  
Monique Sabaty ◽  
Carole Schwintner ◽  
Sandrine Cahors ◽  
Pierre Richaud ◽  
Andre Verméglio
Keyword(s):  
Nitrous Oxide ◽  
Nitrate Reductase ◽  
Rhodobacter Sphaeroides ◽  
Type Strain ◽  
Biochemical Analysis ◽  
Wild Type Strain ◽  
Nitrous Oxide Reductase ◽  
Wild Type ◽  
Genes Encoding ◽  
Membrane Bound

ABSTRACT We have cloned the nap locus encoding the periplasmic nitrate reductase in Rhodobacter sphaeroides f. sp.denitrificans IL106. A mutant with this enzyme deleted is unable to grow under denitrifying conditions. Biochemical analysis of this mutant shows that in contrast to the wild-type strain, the level of synthesis of the nitrite and N2O reductases is not increased by the addition of nitrate. Growth under denitrifying conditions and induction of N oxide reductase synthesis are both restored by the presence of a plasmid containing the genes encoding the nitrate reductase. This demonstrates that R. sphaeroides f. sp. denitrificans IL106 does not possess an efficient membrane-bound nitrate reductase and that nitrate is not the direct inducer for the nitrite and N2O reductases in this species. In contrast, we show that nitrite induces the synthesis of the nitrate reductase.

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.

Multiple isoacceptor forms of several transfer ribonucleic acids in a mutant yeast strain

1978 ◽  
Vol 56 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. B. Bell ◽  
K. Bruce Jacobson ◽  
Lee R. Shugart
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Growth Conditions ◽  
Wild Type ◽  
Reverse Phase ◽  
Ribonucleic Acids ◽  
Multiple Peaks ◽  
Single Form ◽  
In The Wild ◽  
Wild Type Yeast

By use of reverse phase 5 chromatography, a strain of Saccharomyces cerevisiae (XB109-5B) has been shown to exhibit multiple isoaccepting forms for several of the transfer ribonucleic acids (tRNAs). This is in contrast with a standard wild-type strain where only one acceptor is found for each tRNA studied. Multiple peaks for tRNATyr, tRNAPhe, tRNASer, and tRNAVal have been detected for strain XB109-5B. However, the observation of multiple isoacceptors cannot be extended to all tRNAs in this strain since tRNAAsp appears as a single form that is the same as in the wild type. The appearance of multiple peaks was found to depend on the growth conditions of the cells. The tRNA profiles of XB109-5B that was grown rapidly with vigorous aeration differed the most from profiles of comparably grown wild-type yeast, whereas tRNA from this mutant, grown without shaking or supplementary aeration, appeared the same as the wild type. The minor nucleoside composition of the isoacceptors of tRNAPhe was obtained.

scholarly journals Nitric Oxide Is a Signal for NNR-Mediated Transcription Activation in Paracoccus denitrificans

1999 ◽  
Vol 181 (13) ◽  
pp. 4129-4132 ◽  
Author(s):  
Rob J. M. Van Spanning ◽  
Edith Houben ◽  
Willem N. M. Reijnders ◽  
Stephen Spiro ◽  
Hans V. Westerhoff ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Type Strain ◽  
Wild Type Strain ◽  
Paracoccus Denitrificans ◽  
Transcriptional Activator ◽  
Transcription Activation ◽  
Growth Conditions ◽  
Aerobic Respiration ◽  
Wild Type ◽  
In The Wild

ABSTRACT By using the ′lacZ gene, the activities of thenirI, nirS, and norC promoters were assayed in the wild type and in NNR-deficient mutants ofParacoccus denitrificans grown under various growth conditions. In addition, induction profiles of the three promoters in response to the presence of various nitrogenous oxides were determined. Transcription from the three promoters required the absence of oxygen and the presence both of the transcriptional activator NNR and of nitric oxide. The activity of the nnr promoter itself was halved after the cells had been switched from aerobic respiration to denitrification. This response was apparently not a result of autoregulation or of regulation by FnrP, since the nnrpromoter was as active in the wild-type strain as it was in NNR- or FnrP-deficient mutants.

scholarly journals Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Yasumasa Tsukamoto ◽  
Jun-ichi Kato ◽  
Hideo Ikeda
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quantitative Analysis ◽  
Structural Analysis ◽  
Recombination Rate ◽  
Type Strain ◽  
Negative Selection ◽  
Wild Type Strain ◽  
Illegitimate Recombination ◽  
Wild Type ◽  
In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

scholarly journals Activation of 2,4-Diaminoquinazoline in Mycobacterium tuberculosis by Rv3161c, a Putative Dioxygenase

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Eduard Melief ◽  
Shilah A. Bonnett ◽  
Edison S. Zuniga ◽  
Tanya Parish
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Type A ◽  
Wild Type ◽  
Metabolite Analysis ◽  
Content Type ◽  
Data Support ◽  
In The Wild

ABSTRACT The diaminoquinazoline series has good potency against Mycobacterium tuberculosis. Resistant isolates have mutations in Rv3161c, a putative dioxygenase. We carried out metabolite analysis on a wild-type strain and an Rv3161c mutant strain after exposure to a diaminoquinazoline. The parental compound was found in intracellular extracts from the mutant but not the wild type. A metabolite consistent with a monohydroxylated form was identified in the wild type. These data support the hypothesis that Rv3161c metabolizes diaminoquinazolines in M. tuberculosis.

scholarly journals Disruption of the RAD52 gene alters the spectrum of spontaneous SUP4-o mutations in Saccharomyces cerevisiae.

Genetics ◽  
1989 ◽  
Vol 122 (3) ◽  
pp. 535-542 ◽  
Author(s):  
B A Kunz ◽  
M G Peters ◽  
S E Kohalmi ◽  
J D Armstrong ◽  
M Glattke ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Base Pair ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mutator Phenotype ◽  
In The Wild ◽  
Single Base Pair ◽  
Almost All

Abstract Defects in the RAD52 gene of the yeast Saccharomyces cerevisiae confer a mutator phenotype. To characterize this effect in detail, a collection of 238 spontaneous SUP4-o mutations arising in a strain having a disrupted RAD52 gene was analyzed by DNA sequencing. The resulting mutational spectrum was compared to that derived from an examination of 222 spontaneous mutations selected in a nearisogenic wild-type (RAD52) strain. This comparison revealed that the mutator phenotype was associated with an increase in the frequency of base-pair substitutions. All possible types of substitution were detected but there was a reduction in the relative fraction of A.T----G.C transitions and an increase in the proportion of G.C----C.G transversions. These changes were sufficient to cause a twofold greater preference for substitutions at G.C sites in the rad52 strain despite a decrease in the fraction of G.C----T.A transversions. There were also considerable differences between the distributions of substitutions within the SUP4-o gene. Base-pair changes occurred at fewer sites in the rad52 strain but the mutated sites included several that were not detected in the RAD52 background. Only two of the four sites that were mutated most frequently in the rad52 strain were also prominent in the wild-type strain and mutation frequencies at almost all sites common to both strains were greater for the rad52 derivative. Although single base-pair deletions occurred in the two strains with similar frequencies, several classes of mutation that were recovered in the wild-type background including multiple base-pair deletions, insertions of the yeast transposable element Ty, and more complex changes, were not detected in the rad52 strain.(ABSTRACT TRUNCATED AT 250 WORDS)

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