Effect of azasqualene on hopanoid biosynthesis and ethanol tolerance of<i>Zymomonas mobilis</i>

Horbach, Silke; Neuss, Burkard; Sahm, Hermann

doi:10.1111/j.1574-6968.1991.tb04553.x

Cited by 29 publications

(5 citation statements)

References 20 publications

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“…As found for the eukaryotic oxidosqualene cyclases, conserved aspartate residues (Asp-376 and Asp-377) are important for the catalytic activity of SHC and it has been suggested that these amino acids are present in order to stabilise the charge of intermediate cations generated during the cyclization. 1356 2-Aza-2,3-dihydrosqualene has been found to inhibit SHC, 1357 which would certainly be consistent with such a mechanism. SHC has been purified and characterised from Alicyclobacillus acidocaldarius (Bacillus acidocaldarius) 1358 and Rhodopseudomonas palutsris.…”

Section: Biosynthesis Of Hopanoid Triterpenes From Isopentenyl Pyroph...mentioning

confidence: 66%

The biosynthesis of steroids and triterpenoids

Brown¹

1998

Nat. Prod. Rep.

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Section: Biosynthesis Of Hopanoid Triterpenes From Isopentenyl Pyroph...mentioning

confidence: 66%

The biosynthesis of steroids and triterpenoids

Brown¹

1998

Nat. Prod. Rep.

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“…Genes in the fatty acid and hopanoid biosynthetic pathways are upregulated in ZM4 compared to AcR (Additional File 8A). Hopanoids have been found in a variety of bacteria including Z. mobilis and are reported to protect against the toxic effects of ethanol (Flesch and Rohmer, 1989; Hermans et al, 1991; Horbach et al, 1991; Shigeri et al, 1991; Welander et al, 2009). For example, they have also been reported to play a role in Rhodopseudomonas palustris membrane integrity and pH homeostasis (Welander et al, 2009).…”

Section: Resultsmentioning

confidence: 99%

Elucidation of Zymomonas mobilis physiology and stress responses by quantitative proteomics and transcriptomics

et al. 2014

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Zymomonas mobilis is an excellent ethanologenic bacterium. Biomass pretreatment and saccharification provides access to simple sugars, but also produces inhibitors such as acetate and furfural. Our previous work has identified and confirmed the genetic change of a 1.5-kb deletion in the sodium acetate tolerant Z. mobilis mutant (AcR) leading to constitutively elevated expression of a sodium proton antiporter encoding gene nhaA, which contributes to the sodium acetate tolerance of AcR mutant. In this study, we further investigated the responses of AcR and wild-type ZM4 to sodium acetate stress in minimum media using both transcriptomics and a metabolic labeling approach for quantitative proteomics the first time. Proteomic measurements at two time points identified about eight hundreds proteins, or about half of the predicted proteome. Extracellular metabolite analysis indicated AcR overcame the acetate stress quicker than ZM4 with a concomitant earlier ethanol production in AcR mutant, although the final ethanol yields and cell densities were similar between two strains. Transcriptomic samples were analyzed for four time points and revealed that the response of Z. mobilis to sodium acetate stress is dynamic, complex, and involved about one-fifth of the total predicted genes from all different functional categories. The modest correlations between proteomic and transcriptomic data may suggest the involvement of posttranscriptional control. In addition, the transcriptomic data of forty-four microarrays from four experiments for ZM4 and AcR under different conditions were combined to identify strain-specific, media-responsive, growth phase-dependent, and treatment-responsive gene expression profiles. Together this study indicates that minimal medium has the most dramatic effect on gene expression compared to rich medium followed by growth phase, inhibitor, and strain background. Genes involved in protein biosynthesis, glycolysis and fermentation as well as ATP synthesis and stress response play key roles in Z. mobilis metabolism with consistently strong expression levels under different conditions.

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“…There is a large body of evidence supporting a possible role of apolar polyisoprenoids as membrane regulators. To begin with, studies about lycopene contents of Haloferax volcanii and Zymomonas mobilis show that apolar polyisoprenoid levels are growth phase dependent, with increased synthesis in stationary phase [165,166]. The high energy-cost of lycopene synthesis, i.e., 24 ATP and 12 NADH per molecule, suggests that the presence of squalene-type isoprenoids must be essential for cell viability in the stationary phase.…”

Section: Apolar Polyisoprenoidsmentioning

confidence: 99%

In Search for the Membrane Regulators of Archaea

Salvador-Castell

Tourte

Oger

2019

IJMS

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Membrane regulators such as sterols and hopanoids play a major role in the physiological and physicochemical adaptation of the different plasmic membranes in Eukarya and Bacteria. They are key to the functionalization and the spatialization of the membrane, and therefore indispensable for the cell cycle. No archaeon has been found to be able to synthesize sterols or hopanoids to date. They also lack homologs of the genes responsible for the synthesis of these membrane regulators. Due to their divergent membrane lipid composition, the question whether archaea require membrane regulators, and if so, what is their nature, remains open. In this review, we review evidence for the existence of membrane regulators in Archaea, and propose tentative location and biological functions. It is likely that no membrane regulator is shared by all archaea, but that they may use different polyterpenes, such as carotenoids, polyprenols, quinones and apolar polyisoprenoids, in response to specific stressors or physiological needs.

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Effect of azasqualene on hopanoid biosynthesis and ethanol tolerance ofZymomonas mobilis

Cited by 29 publications

References 20 publications

The biosynthesis of steroids and triterpenoids

The biosynthesis of steroids and triterpenoids

Elucidation of Zymomonas mobilis physiology and stress responses by quantitative proteomics and transcriptomics

In Search for the Membrane Regulators of Archaea

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