scholarly journals SigF Controls Carotenoid Pigment Production and Affects Transformation Efficiency and Hydrogen Peroxide Sensitivity in Mycobacterium smegmatis

2008 ◽  
Vol 190 (23) ◽  
pp. 7859-7863 ◽  
Author(s):  
Roberta Provvedi ◽  
Dana Kocíncová ◽  
Valentina Donà ◽  
Daniel Euphrasie ◽  
Mamadou Daffé ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Mycobacterium Smegmatis ◽  
Transformation Efficiency ◽  
Pigment Production ◽  
Carotenoid Pigment ◽  
Increased Sensitivity ◽  
Carotenoid Synthesis ◽  
Complex Lipids ◽  
Wall Permeability ◽  
Cell Wall Permeability

ABSTRACT Carotenoids are complex lipids that are known for acting against photodynamic injury and free radicals. We demonstrate here that σF is required for carotenoid pigment production in Mycobacterium smegmatis. We further show that a sigF mutant exhibits a transformation efficiency 104-fold higher than that of the parental strain, suggesting that σF regulates the production of components affecting cell wall permeability. In addition, a sigF mutant showed an increased sensitivity to hydrogen peroxide. An in silico search of the M. smegmatis genome identified a number of SigF consensus sites, including sites upstream of the carotenoid synthesis locus, which explains its SigF regulation.

The cell envelope structure and properties of Mycobacterium smegmatis mc2155: is there a clue for the unique transformability of the strain?

Microbiology ◽  
2005 ◽  
Vol 151 (6) ◽  
pp. 2075-2086 ◽  
Author(s):  
Gilles Etienne ◽  
Françoise Laval ◽  
Christelle Villeneuve ◽  
Premkumar Dinadayala ◽  
Ahmed Abouwarda ◽  
...  
Keyword(s):  
Mycobacterium Smegmatis ◽  
Biochemical Analysis ◽  
Wild Type Strain ◽  
Ultrastructural Change ◽  
Cell Envelope ◽  
Structure And Properties ◽  
Wild Type ◽  
Surrogate Host ◽  
Wall Permeability ◽  
Cell Wall Permeability

Mycobacterium smegmatis is often used as a surrogate host for pathogenic mycobacteria, especially since the isolation of the transformable smooth morphotype strain mc2155 from the isogenic rough wild-type strain ATCC 607. Biochemical analysis of the cell envelope components revealed a lack of polar glycolipids, namely the lipooligosaccharides and the polar subfamilies of glycopeptidolipids, in the mc2155 strain. In addition, the latter strain differs from its parent by the distribution of various species of glycolipids and phospholipids between the outermost and deeper layers of the cell envelope. The presence of filamentous and rope-like structures at the cell surface of mc2155 cells grown in complex media further supported an ultrastructural change in the cell envelope of the mutant. Importantly, a significantly more rapid uptake of the hydrophobic chenodeoxycholate was observed for the mutant compared to wild-type cells. Taken together, these data indicate that the nature of the surface-exposed and envelope constituents is crucial for the surface properties, cell wall permeability and bacterial phenotype, and suggest that the transformable character of the mc2155 strain may be in part explained by these profound modifications of its cell envelope.

scholarly journals Novel Polyoxyethylene-Containing Glycolipids Are Synthesized inCorynebacterium matruchotiiandMycobacterium smegmatisCultured in the Presence of Tween 80

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Cindy Wang ◽  
Engy A. Mahrous ◽  
Richard E. Lee ◽  
Martha M. Vestling ◽  
Kuni Takayama
Keyword(s):  
Cell Wall ◽  
Mycobacterium Smegmatis ◽  
Furan Ring ◽  
Tween 80 ◽  
Underlying Mechanism ◽  
Maldi Mass Spectrometry ◽  
Cell Permeability ◽  
Sorbitan Monooleate ◽  
Wall Permeability ◽  
Cell Wall Permeability

The addition of polyoxyethylene sorbitan monooleate (Tween 80) to a culture of mycobacteria greatly influences cell permeability and sensitivity to antibiotics but very little is known regarding the underlying mechanism. Here we show thatCorynebacterium matruchotii(surrogate of mycobacteria) converts Tween 80 to a structural series of polyoxyethylenic acids which are then used to form novel series-2A and series-2B glycolipids. Minor series-3 glycolipids were also synthesized. The polyoxyethylenic acids replaced corynomycolic acids in the cell wall. Correspondingly the trehalose dicorynomycolate content was reduced. MALDI mass spectrometry, MS-MS,1H-NMR, and13C-NMR were used to characterize the series-2 glycolipids. Series-2A glycolipid is trehalose 6-C36:2-corynomycolate-6′-polyoxyethylenate and series-2B glycolipid is trehalose 6-C36:2-corynomycolate-6′-furan ring-containing polyoxyethylenate.Mycobacterium smegmatisgrown in the presence of Tween 80 also synthesizes series-2 type glycolipids. The synthesis of these novel glycolipids in corynebacteria and mycobacteria should result in gross changes in the cell wall permeability and drug sensitivity.

Mycobacterium smegmatis msmeg_3314 is involved in pyrazinamide and fluoroquinolones susceptibility via NAD+/NADH dysregulation

2020 ◽  
Vol 15 (6) ◽  
pp. 413-426
Author(s):  
Junqi Xu ◽  
Yu Chen ◽  
Xi Mou ◽  
Yu Huang ◽  
Shuang Ma ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Wall ◽  
Resistance Genes ◽  
Mycobacterium Smegmatis ◽  
Proton Motive Force ◽  
Glyoxylate Shunt ◽  
Oxygen Species ◽  
Scavenging Capacity ◽  
Wall Permeability ◽  
Cell Wall Permeability

Aim: To identify and characterize new mycobacterium pyrazinamide (PZA) resistance genes in addition to pncA, rpsA and panD. Materials & methods: To screen a Tn7 M. smegmatis mc2155 transposon library using 50 μM PZA and a PZA hypersensitive mutant (M492) was obtained. MIC was further used to confirm the hypersensitivity of M492 mutant by culturing the mutant in Middlebrook 7H9 liquid medium at 37°C. Results: msmeg_3314 is the gene underlying the hypersensitive phenotype of mutant M492. The observed resistance to PZA and fluoroquinolones involved the alteration of Mycobacterium cell wall permeability and the dissipation of the proton motive force. NAD+/NADH dysregulation and attenuated glyoxylate shunt might underlie the declined scavenging capacity of reactive oxygen species in the msmeg_3314-deficient mutants. Conclusion: msmeg_ 3314 is a novel gene involved in pyrazinamide resistance and might be a new candidate for drugs target.

Cell Wall Permeability of Pinto Bean Cotyledon Cells Regulates In Vitro Fecal Fermentation and Gut Microbiota

2021 ◽  
Author(s):  
Yanrong Huang ◽  
Sushil Dhital ◽  
Feitong Liu ◽  
Xiong Fu ◽  
Qiang Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Microbiota Composition ◽  
Colonic Fermentation ◽  
Pinto Bean ◽  
Wall Permeability ◽  
Cell Wall Permeability ◽  
Cotyledon Cells ◽  
Whole Foods

Processing induced structural changes of whole foods on regulation of colonic fermentation rate and microbiota composition are least understood and often overlooked. In the present study, intact cotyledon cells from...

scholarly journals Uremic toxins promote accumulation of oxidized protein and increased sensitivity to hydrogen peroxide in endothelial cells by impairing the autophagic flux

2020 ◽  
Vol 523 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Silvia D. Rodrigues ◽  
Sabrina S. Santos ◽  
Tassiana Meireles ◽  
Natalia Romero ◽  
Griet Glorieux ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Endothelial Cells ◽  
Uremic Toxins ◽  
Autophagic Flux ◽  
Increased Sensitivity

scholarly journals AnkB, a Periplasmic Ankyrin-Like Protein inPseudomonas aeruginosa, Is Required for Optimal Catalase B (KatB) Activity and Resistance to Hydrogen Peroxide

2000 ◽  
Vol 182 (16) ◽  
pp. 4545-4556 ◽  
Author(s):  
Michael L. Howell ◽  
Eyad Alsabbagh ◽  
Ju-Fang Ma ◽  
Urs A. Ochsner ◽  
Martin G. Klotz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Hydrogen Peroxide ◽  
Cytoplasmic Membrane ◽  
Membrane Vesicles ◽  
Gene Encoding ◽  
Rnase Protection ◽  
C Terminus ◽  
Hydrophobic Amino Acids ◽  
Increased Sensitivity ◽  
Membrane Spanning

ABSTRACT In this study, we have cloned the ankB gene, encoding an ankyrin-like protein in Pseudomonas aeruginosa. TheankB gene is composed of 549 bp encoding a protein of 183 amino acids that possesses four 33-amino-acid ankyrin repeats that are a hallmark of erythrocyte and brain ankyrins. The location ofankB is 57 bp downstream of katB, encoding a hydrogen peroxide-inducible catalase, KatB. Monomeric AnkB is a 19.4-kDa protein with a pI of 5.5 that possesses 22 primarily hydrophobic amino acids at residues 3 to 25, predicting an inner-membrane-spanning motif with the N terminus in the cytoplasm and the C terminus in the periplasm. Such an orientation in the cytoplasmic membrane and, ultimately, periplasmic space was confirmed using AnkB-BlaM and AnkB-PhoA protein fusions. Circular dichroism analysis of recombinant AnkB minus its signal peptide revealed a secondary structure that is ∼65% α-helical. RNase protection and KatB- and AnkB-LacZ translational fusion analyses indicated that katBand ankB are part of a small operon whose transcription is induced dramatically by H2O2, and controlled by the global transactivator OxyR. Interestingly, unlike the spherical nature of ankyrin-deficient erythrocytes, the cellular morphology of anankB mutant was identical to that of wild-type bacteria, yet the mutant produced more membrane vesicles. The mutant also exhibited a fourfold reduction in KatB activity and increased sensitivity to H2O2, phenotypes that could be complemented in trans by a plasmid constitutively expressing ankB. Our results suggest that AnkB may form an antioxidant scaffolding with KatB in the periplasm at the cytoplasmic membrane, thus providing a protective lattice work for optimal H2O2 detoxification.

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