Microbial Lipids

“…As shown in Fig. 6, K. aerogenes only contained PE and PG plus PS as phospholipids, in agreement with PE being the most abundant phospholipid in many Gram-negative and Gram-positive bacterial species (16,30). In contrast to the MLB situation, PC, PI, and lipid L1 were not detected in K. aerogenes.…”

Section: Resultsmentioning

confidence: 58%

Lipid Composition of Multilamellar Bodies Secreted by Dictyostelium discoideum Reveals Their Amoebal Origin

et al. 2013

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When they are fed with bacteria, Dictyostelium discoideum amoebae produce and secrete multilamellar bodies (MLBs), which are composed of membranous material. It has been proposed that MLBs are a waste disposal system that allows D. discoideum to eliminate undigested bacterial remains. However, the real function of MLBs remains unknown. Determination of the biochemical composition of MLBs, especially lipids, represents a way to gain information about the role of these structures. To allow these analyses, a protocol involving various centrifugation procedures has been developed to purify secreted MLBs from amoeba-bacterium cocultures. The purity of the MLB preparation was confirmed by transmission electron microscopy and by immunofluorescence using H36, an antibody that binds to MLBs. The lipid and fatty acid compositions of pure MLBs were then analyzed by high-performance thin-layer chromatography (HPTLC) and gas chromatography (GC), respectively, and compared to those of amoebae as well as bacteria used as a food source. While the bacteria were devoid of phosphatidylcholine (PC) and phosphatidylinositol (PI), these two polar lipid species were major classes of lipids in MLBs and amoebae. Similarly, the fatty acid composition of MLBs and amoebae was characterized by the presence of polyunsaturated fatty acids, while cyclic fatty acids were found only in bacteria. These results strongly suggest that the lipids constituting the MLBs originate from the amoebal metabolism rather than from undigested bacterial membranes. This opens the possibility that MLBs, instead of being a waste disposal system, have unsuspected roles in D. discoideum physiology.

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“…Lysine esterification of one of the two hydroxyl groups of PG results in the free amino groups imparting a net positive charge on PG, creating lysyl-phosphatidylglycerol (L-PG) (73,87). The presence of L-PG and the process of lysinylation have been described for several bacterial pathogens, including S. aureus (78,87), L. monocytogenes (79,88), and Mycobacterium tuberculosis (89), as well as some soil organisms, such as Bacillus species (90,91).…”

Section: Mprfmentioning

confidence: 99%

“…Membranes contain phospholipids whose composition and relative abundance vary profoundly, both between species and under various environmental conditions and growth phases (73,74). The most common bacterial phospholipids are phosphatidylglycerol (PG) and diphosphatidylglycerol (cardiolipin), whose head groups are negatively charged (75).…”

Section: Lipid Compositionmentioning

confidence: 99%

Lantibiotic Resistance

Draper

Cotter

Hill

et al. 2015

Microbiol Mol Biol Rev

132

129

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SUMMARY The dramatic rise in the incidence of antibiotic resistance demands that new therapeutic options will have to be developed. One potentially interesting class of antimicrobials are the modified bacteriocins termed lantibiotics, which are bacterially produced, posttranslationally modified, lanthionine/methyllanthionine-containing peptides. It is interesting that low levels of resistance have been reported for lantibiotics compared with commercial antibiotics. Given that there are very few examples of naturally occurring lantibiotic resistance, attempts have been made to deliberately induce resistance phenotypes in order to investigate this phenomenon. Mechanisms that hinder the action of lantibiotics are often innate systems that react to the presence of any cationic peptides/proteins or ones which result from cell well damage, rather than being lantibiotic specific. Such resistance mechanisms often arise due to altered gene regulation following detection of antimicrobials/cell wall damage by sensory proteins at the membrane. This facilitates alterations to the cell wall or changes in the composition of the membrane. Other general forms of resistance include the formation of spores or biofilms, which are a common mechanistic response to many classes of antimicrobials. In rare cases, bacteria have been shown to possess specific antilantibiotic mechanisms. These are often species specific and include the nisin lytic protein nisinase and the phenomenon of immune mimicry.

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Microbial Lipids

Abstract: 159 160 162 162 163 3.4 Algae 164 167 168 169 Biotechnology Edited by H.-J. Rehm and G. Reed OVCH Verlagsgesellschaft mbH, 1997 (Y-18~3, 13% a Also known as peanut oil. yLinolenic acid, 18:3 (6, 9, 12).

Cited by 96 publications

References 188 publications

Structure and reactivity of LpxD, the N -acyltransferase of lipid A biosynthesis

Structure and reactivity of LpxD, the N -acyltransferase of lipid A biosynthesis

Lipid Composition of Multilamellar Bodies Secreted by Dictyostelium discoideum Reveals Their Amoebal Origin

Lantibiotic Resistance

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