Contributions of Membrane Lipids to Bacterial Cell Homeostasis upon Osmotic Challenge

Romantsov, Tatyana; Wood, Janet M.

doi:10.1007/978-3-319-43676-0_58-1

Cited by 3 publications

(2 citation statements)

References 111 publications

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“…The stability of the membrane and, accordingly, the decrease of the permeability, can be enhanced by increasing the fatty acyl chain length [33]. Conversely, the fluidity and permeability can be increased by introducing a double bond or a cyclopropyl (more stable to acidic conditions than a double bond), or a terminally branched methyl on the fatty acyl chain [34].…”

Section: Discussionmentioning

confidence: 99%

Membrane phospholipid composition of Pseudomonas aeruginosa grown in a cystic fibrosis mucus-mimicking medium

Deschamps

Schaumann

Schmitz-Afonso

et al. 2021

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Section: Discussionmentioning

confidence: 99%

Membrane phospholipid composition of Pseudomonas aeruginosa grown in a cystic fibrosis mucus-mimicking medium

Deschamps

Schaumann

Schmitz-Afonso

et al. 2021

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…In the eukaryotic plasma membrane, phospholipids and sterols are the main membrane components (Maxfiled and van Meer, 2010), and among the phospholipids, phosphatidylcholine (PC) is the most abundant (Harayama and Riezman, 2018). Among the prokaryotic cells, most of the bacteria have only phospholipids as lipid components of their cytoplasmic membrane (Strahl and Errington, 2017) and more specifically phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) are the most abundant (Romantsov and Wood, 2016).…”

Section: Introductionmentioning

confidence: 99%

Structural Characterization of Natural Yeast Phosphatidylcholine and Bacterial Phosphatidylglycerol Lipid Multilayers by Neutron Diffraction

et al. 2021

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Eukaryotic and prokaryotic cell membranes are difficult to characterize directly with biophysical methods. Membrane model systems, that include fewer molecular species, are therefore often used to reproduce their fundamental chemical and physical properties. In this context, natural lipid mixtures directly extracted from cells are a valuable resource to produce advanced models of biological membranes for biophysical investigations and for the development of drug testing platforms. In this study we focused on single phospholipid classes, i.e. Pichia pastoris phosphatidylcholine (PC) and Escherichia coli phosphatidylglycerol (PG) lipids. These lipids were characterized by a different distribution of their respective acyl chain lengths and number of unsaturations. We produced both hydrogenous and deuterated lipid mixtures. Neutron diffraction experiments at different relative humidities were performed to characterize multilayers from these lipids and investigate the impact of the acyl chain composition on the structural organization. The novelty of this work resides in the use of natural extracts with a single class head-group and a mixture of chain compositions coming from yeast or bacterial cells. The characterization of the PC and PG multilayers showed that, as a consequence of the heterogeneity of their acyl chain composition, different lamellar phases are formed.

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Gene targets for engineering osmotolerance in Caldicellulosiruptor bescii

Sander

Chung

Klingeman

et al. 2020

Biotechnol Biofuels

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Background Caldicellulosiruptor bescii, a promising biocatalyst being developed for use in consolidated bioprocessing of lignocellulosic materials to ethanol, grows poorly and has reduced conversion at elevated medium osmolarities. Increasing tolerance to elevated fermentation osmolarities is desired to enable performance necessary of a consolidated bioprocessing (CBP) biocatalyst. Results Two strains of C. bescii showing growth phenotypes in elevated osmolarity conditions were identified. The first strain, ORCB001, carried a deletion of the FapR fatty acid biosynthesis and malonyl-CoA metabolism repressor and had a severe growth defect when grown in high-osmolarity conditions—introduced as the addition of either ethanol, NaCl, glycerol, or glucose to growth media. The second strain, ORCB002, displayed a growth rate over three times higher than its genetic parent when grown in high-osmolarity medium. Unexpectedly, a genetic complement ORCB002 exhibited improved growth, failing to revert the observed phenotype, and suggesting that mutations other than the deleted transcription factor (the fruR/cra gene) are responsible for the growth phenotype observed in ORCB002. Genome resequencing identified several other genomic alterations (three deleted regions, three substitution mutations, one silent mutation, and one frameshift mutation), which may be responsible for the observed increase in osmolarity tolerance in the fruR/cra-deficient strain, including a substitution mutation in dnaK, a gene previously implicated in osmoresistance in bacteria. Differential expression analysis and transcription factor binding site inference indicates that FapR negatively regulates malonyl-CoA and fatty acid biosynthesis, as it does in many other bacteria. FruR/Cra regulates neighboring fructose metabolism genes, as well as other genes in global manner. Conclusions Two systems able to effect tolerance to elevated osmolarities in C. bescii are identified. The first is fatty acid biosynthesis. The other is likely the result of one or more unintended, secondary mutations present in another transcription factor deletion strain. Though the locus/loci and mechanism(s) responsible remain unknown, candidate mutations are identified, including a mutation in the dnaK chaperone coding sequence. These results illustrate both the promise of targeted regulatory manipulation for osmotolerance (in the case of fapR) and the challenges (in the case of fruR/cra).

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Contributions of Membrane Lipids to Bacterial Cell Homeostasis upon Osmotic Challenge

Cited by 3 publications

References 111 publications

Membrane phospholipid composition of Pseudomonas aeruginosa grown in a cystic fibrosis mucus-mimicking medium

Membrane phospholipid composition of Pseudomonas aeruginosa grown in a cystic fibrosis mucus-mimicking medium

Structural Characterization of Natural Yeast Phosphatidylcholine and Bacterial Phosphatidylglycerol Lipid Multilayers by Neutron Diffraction

Gene targets for engineering osmotolerance in Caldicellulosiruptor bescii

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