Changes of Fatty Acid Composition of Chlorobium limicola IMV K-8 Cells under the Influence of Copper (II) Sulfate

Abstract

To investigate the changes of fatty acid composition of green sulphur bacteria Chlorobium limicola ІМV К-8 cells at the influence of copper (II) sulfate. Methods. Microbiological, biochemical, biometrical. Results. The increase of content of long chain saturated fatty acids of C. limicola ІМV К-8 cells, in particular pentadecanoic, hexadecanoic, heptadecanoic and octadecanoic acids was observed under the influence of copper (II) sulfate in concentrations which caused decrease of biomass accumulation up to 70 %. Among the first reactions of adaptation of C. limicola ІМV К-8 cells under these conditions are cis/trans isomerisation of monounsaturated fatty acids and synthesis of cyclopropane fatty acids. Maintenance of appropriate level of membrane fluidity is provided by branched chain fatty acids. Conclusions. Under the influence of copper (II) sulfate on C. limicola ІМV К-8 cells fatty acids composition of membranes is changed, which causes the increase of membranes fluidity, and, probably, is contributed to more efficient efflux of Cu 2+ ions.

Biochemical indicators of green photosynthetic bacteria Chlorobium limicola response to Cu(2+) action

“…Maintenance of GSH/GSSG ratio is strictly con trolled at the transcriptional, translational and posttranslational level [21,22]. In the previous work, we established that glutathione system is an important part of the antioxidative defence of C. limicola under the influence of copper (II) sulfate [23]. We suppose that the increase in GSSG level in cell-free extracts of C. limicola under the influence of copper (II) sulfate can be the consequence of the glutathione peroxi dase or glutathione-S-transferase activity in Superoxide dismutase (SOD) is an impor tant part of the antioxidative defense of anaerobic bacteria [7].…”

“…Changes in the fatty acids composition of membrane lipids, or "homeophase adaptation", are important for the maintenance of the optimal bacte rial membrane fluidity under the influence of toxic compounds [8]. As it was established in our previous work [25] cis/trans isomerization of monounsatu rated fatty acids and synthesis of cyclopropane fatty acids are the first reactions of C. limicola cells adaptation under the influence of Cu 2+ cations. For the estimation of cytoplasm membrane fluidity, we used the index of cellular lipids unsaturation and the in dex of membrane viscosity [8].…”

“…Genes and amino acid sequences of thioredoxin dependent thiol per oxidase (NC_002932.3) and 2-Cys-peroxiredoxin (NC_002932.3) of C. tepidum TLS are deposited in the GenBank database [18]. Thiol peroxidases and 2-Cys-peroxiredoxins provide the degradation of long-chain fatty acids peroxides and hydrogen per oxide [25]. Cytochrome c peroxidase, which can also be involved in the antioxidative defense, is revealed in C. chlorochromatii [18].…”

Relationships between prooxidant and antioxidant parameters of bacteria of sulfur cycle under the influence of heavy metal compounds

“…Cell membranes are one of the main targets of heavy metal ions, so the mechanisms of adaptation to the influence of its components are to maintain an appropriate level of membrane fluidity. Changes in the fatty acid composition of membrane lipids are the most important reactions of the cell during oxidative stress 30 .…”

“…A probable way of adaptation of C. limicola IMV K-8 cells to the influence of copper ions is to change the fatty acid composition of lipids, which increases the fluidity of the membrane and probably necessary for more efficient efflux of metal ions from bacterial cells 31 . Under the 30 influence of copper (II) sulfate, an increase in the content of octadecanoic, pentadecanoic, heptadecanoic, hexadecanoic, cis-9-hexadecane, trans-9octadecenoic, cis-9,10-methylenehexadecanoic and i15: 0iso-12-methyl tetradecanoic acid. Under these conditions, the content of tetradecanoic and cis-9-octadecenoic acids decreases (table 6).…”