Lipid Composition of Gram-Negative Bacteria, Sensitive and Resistant to Streptomycin

Abstract

Analyses of streptomycin-sensitive and -resistant gram-negative bacteria show that, contrary to previous reports, the development of antibiotic resistance is not accompanied by changes in membrane lipid or fatty acid composition.

Mechanisms of Selective Antimicrobial Activity of Gaegurin 4

“…Firstly, the selective activity of GGN4 may be due to PC present in the human RBC membrane. Human RBC is composed of PE, PC, PS, and sphingomylein (22, 25, 10, 18%), whereas bacterial membranes do not contain PC (Bishop et al, 1967;Bishop et al, 1973;Clejan et al, 1986;Gennis, 1991;Morein et al, 1996). In this study, GGN4-induced conductance in PC containing membranes was significantly smaller than that in pure PE membranes, indicating that the selective activity of GGN4 could be due, in part, to PC in RBC membranes.…”

“…The findings that addition of PS to the planar bilayers increased the slope of double logarithmic concentration-conductance curves (from 0.391 to 0.738) also indicate that more peptides are involved in the ionophoric activity in the bilayers containing PS (Kagan et al, 1990). It is known that the portions of negatively charged lipids such as phosphatidylglycerol and cardiolipin are rich in B. subtilis membranes (70∼80%; Bishop et al, 1967;Clejan et al, 1986), but low in the membranes of E. coli cells (17∼ 26%; Bishop et al, 1973;Morein et al, 1996). Therefore, the higher ionophoric activity of GGN4 in the bilayers formed with the lipids from Gram-positive bacteria, B. subtilis, is likely due to a stronger electrostatic interaction of positive charges in GGN4 molecules and negative surface charges on the planar lipid bilayers (Dathe et al, 1996).…”

Impact of microbial activities and hydraulic retention time on the production and profile of long chain fatty acids in grease interceptors: a laboratory study

“…7 Besides, the composition profile of the retained LCFAs also indicates that LCFAs from microbial cell membranes are negligible because some of the dominant LCFAs in the cell membrane (such as C16 : 0 and C18 : 0 28 ) were observed to be few inside GIs, while the dominant polyunsaturated LCFAs in GIs (such as C18 : 2 and C18 : 3) are barely observed in the cell membrane. 28,29 Regarding the formation of FOG deposits in the sewer systems, the disturbance of the LCFA layer within GI can be more detrimental to the downstream sewer pipeline as a higher concentration of unsaturated fatty acids (such as C18 : 1, C18 : 2 and C18 : 3) would be discharged. Since the depth of FOG and the food particle layer increased significantly during the operation of real GIs, 30 the water layer in the middle of GI would be gradually reduced in volume.…”

Study on Lipid Fractions of Streptococcus thermophilus by TLC, GC and GC/MS Techniques

“…The fatty acid composition of the whole lipid fraction, particularly in Gram-negative bacteria, has been widely investigated to support microbial characterization and to provide targets for antibacterial drugs. It is known that microbial fatty acid composition is dependent upon several factors and it is often modified in response to environmental physicochemical parameters such as oxygen, temperature, nutrients, growth phase and pH value [7][8][9][10][11][12][13][14][15][16]. Different analytical procedures have been applied for the determination of bacterial fatty acids: acid or alkaline direct transesterification of the cells [17], methylation of the whole fat extracted, preceded or not by saponification [4,5,8,12,16].…”