The lipidome of the photosynthetic bacterium Rhodobacter sphaeroides R26 is affected by cobalt and chromate ions stress

Abstract

A detailed characterization of membrane lipids of the photosynthetic bacterium Rhodobacter (R.) sphaeroides was accomplished by thin-layer chromatography coupled with matrix-assisted laser desorption ionization mass spectrometry. Such an approach allowed the identification of the main membrane lipids belonging to different classes, namely cardiolipins (CLs), phosphatidylethanolamines, phosphatidylglycerols (PGs), phosphatidylcholines, and sulfoquinovosyldiacylglycerols (SQDGs). Thus, the lipidomic profile of R. sphaeroides R26 grown in abiotic stressed conditions by exposure to bivalent cobalt cation and chromate oxyanion, was investigated. Compared to bacteria grown under control conditions, significant lipid alterations take place under both stress conditions; cobalt exposure stress results in the relative content increase of CLs and SQDGs, most likely compensating the decrease in PGs content, whereas chromate stress conditions result in the relative content decrease of both PGs and SQDGs, leaving CLs unaltered. For the first time, the response of R. sphaeroides to heavy metals as Co(2+) and CrO4 (2-) is reported and changes in membrane lipid profiles were rationalised.

Light-driven ATP production promotes mRNA biosynthesis inside hybrid multi-compartment artificial protocells

“…The chromatophore diameter was measured by dynamic light scattering (mode 68 nm; mean 80 ± 23 nm, Figure 2b), while their zeta potential is -30.9 ± 0.6 mV (mean ± SD), as expected for the presence of ~ 60 mol% of anionic phospholipids in the R. sphaeroides membrane 29,30 .…”

MALDI‐TOF mass spectrometry analysis of proteins and lipids in Escherichia coli exposed to copper ions and nanoparticles

“…Actually, there is an emerging interest in developing new analytical methods for lipid analysis aimed to identify bacterial taxonomy, to understand the membrane structure, to follow growth changes and metabolic processes and to highlight changes arising from normal or stressed growth conditions . In this work, the first goal was to generate reproducible protocols for MALDI TOF MS analysis of both protein and lipid fractions from bacteria aimed at monitoring molecular modifications.…”

“…Actually, there is an emerging interest in developing new analytical methods for lipid analysis aimed to identify bacterial taxonomy, to understand the membrane structure, to follow growth changes and metabolic processes and to highlight changes arising from normal or stressed growth conditions. [28,29] In this work, the first goal was to generate reproducible protocols for MALDI TOF MS analysis of both protein and lipid fractions from bacteria aimed at monitoring molecular modifications. At first, the main critical experimental parameters (selection of the MALDI matrix, optimal solvent composition, sample preparation method, lipid/protein extraction protocol) for the MS analyses were optimized on a selected E. coli strain with stable growing conditions.…”

Electron-Transfer Secondary Reaction Matrices for MALDI MS Analysis ofBacteriochlorophyll ainRhodobacter sphaeroidesand Its Zinc and Copper Analogue Pigments

“…This distinctive feature explains their functioning in the dark and in places typically unreachable to other photosynthetic systems such as deep soil and sea, or internal organs of living species. For these reasons, BChl have a larger range of applications compared with Chl as they can be involved in bioremediation [5,6] or, very importantly, as elements of nanostructures in photodynamic therapy and nanomedicine [7,8]. Naturally occurring BChl and their derivatives represent an important group of photosensitizers (PS) since the strong absorption in the infra-red spectral region enables ablation of tumors that cannot be accessed by commonly employed PS such as chlorophylls, porphyrins, and phthalocyanines absorbing at shorter wavelengths.…”