Cold dependence of fatty acid profile of different lipid structures of Listeria monocytogenes

Previous studies have demonstrated that the branched-chain fatty acid anteiso-C 15:0 plays a critical role in the growth of Listeria monocytogenes at low temperatures by ensuring sufficient membrane fluidity. Studies utilizing a chemically defined minimal medium revealed that the anteiso fatty acid precursor isoleucine largely determined the fatty acid profile and fatty acid response of the organism to lowered growth temperature. When isoleucine was sufficient, the fatty acid profile was very uniform, with anteiso fatty acids comprising up to 95% of total fatty acid, and the major fatty acid adjustment to low temperature was fatty acid chain shortening, which resulted in an increase of anteiso-C 15:0 solely at the expense of anteiso-C 17:0 . When isoleucine was not supplied, the fatty acid profile became more complex and was readily modified by leucine, which resulted in a significant increase of corresponding iso fatty acids and an inability to grow at 10°C. Under this condition, the increase of anteiso-C 15:0 at low temperature resulted from the combined effect of increasing the anteiso:iso ratio and chain shortening. A branched-chain ␣-keto acid dehydrogenase-defective strain largely lost the ability to increase the anteiso:iso ratio. Cerulenin, an inhibitor of ␤-ketoacyl-acyl carrier protein synthase (FabF), induced a similar fatty acid chain shortening as low temperature did. We propose that the anteiso precursor preferences of enzymes in the branched-chain fatty acid biosynthesis pathway ensure a high production of anteiso fatty acids, and cold-regulated chain shortening results in a further increase of anteiso-C 15:0 at the expense of anteiso-C 17:0 .

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confidence: 89%

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confidence: 99%

Exogenous Isoleucine and Fatty Acid Shortening Ensure the High Content of Anteiso-C _15:0 Fatty Acid Required for Low-Temperature Growth of Listeria monocytogenes

Zhu

Ding

Julotok

et al. 2005

“…L. monocytogenes has a fatty acid composition that is dominated to an unusual extent (90% or more) by branched-chain fatty acids (BCFAs); the major fatty acids are anteiso-C 15:0 , anteiso-C 17:0 , and iso-C 15:0 . Numerous studies have shown that the major change in fatty acid composition when L. monocytogenes is grown at low temperatures is an increase in the content of anteiso-C 15:0 fatty acid to 65% or more of the total (1,12,23,25,26,28). Two cold-sensitive mutants with Tn917 insertions in the branchedchain ␣-keto acid dehydrogenase gene complex (bkd) were deficient in BCFAs, grew poorly at low temperatures, and had decreased membrane fluidity; all of these defects could be restored by growth in the presence of 2-methylbutyrate (2-MB), a precursor of odd-numbered anteiso fatty acids, including anteiso-C 15:0 fatty acid (1,7,13,37).…”

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confidence: 99%

Influence of Fatty Acid Precursors, Including Food Preservatives, on the Growth and Fatty Acid Composition of Listeria monocytogenes at 37 and 10°C

Julotok

Singh

Gatto

et al. 2010

Listeria monocytogenes is a food-borne pathogen that grows at refrigeration temperatures and increases its content of anteiso-C 15:0 fatty acid, which is believed to be a homeoviscous adaptation to ensure membrane fluidity, at these temperatures. As a possible novel approach for control of the growth of the organism, the influences of various fatty acid precursors, including branched-chain amino acids and branched-and straightchain carboxylic acids, some of which are also well-established food preservatives, on the growth and fatty acid composition of the organism at 37°C and 10°C were studied in order to investigate whether the organism could be made to synthesize fatty acids that would result in impaired growth at low temperatures. The results indicate that the fatty acid composition of L. monocytogenes could be modulated by the feeding of branchedchain amino acid, C 4 , C 5 , and C 6 branched-chain carboxylic acid, and C 3 and C 4 straight-chain carboxylic acid fatty acid precursors, but the growth-inhibitory effects of several preservatives were independent of effects on fatty acid composition, which were minor in the case of preservatives metabolized via acetyl coenzyme A. The ability of a precursor to modify fatty acid composition was probably a reflection of the substrate specificities of the first enzyme, FabH, in the condensation of primers of fatty acid biosynthesis with malonyl acyl carrier protein.Listeriosis is a severe and life-threatening human infection encompassing meningoencephalitis, meningitis, focal infections in the immunocompromised, and stillbirths and neonatal sepsis due to infection of pregnant women (2). The disease is caused by the Gram-positive food-borne pathogen Listeria monocytogenes, which is responsible for common-source and sporadic disease involving a variety of different foods (27). Listeriosis has a high fatality rate (24). The U.S. Department of Agriculture has a zero tolerance policy for L. monocytogenes in ready-to-eat products, and high costs are associated with product recalls.L. monocytogenes has a remarkably low minimum growth temperature, e.g., Ϫ0.1°C (34), and thus the organism can multiply to dangerous levels when food is kept at refrigeration temperatures. We are interested in the molecular mechanisms of L. monocytogenes psychrotolerance, with a view to applying this knowledge to improve the control of the growth of the organism. Although the adaptations involved in low-temperature tolerance are global in scope, we have focused on changes in fatty acid composition that result in homeoviscous adjustments of membrane fluidity (31, 36). L. monocytogenes has a fatty acid composition that is dominated to an unusual extent (90% or more) by branched-chain fatty acids (BCFAs); the major fatty acids are anteiso-C 15:0 , anteiso-C 17:0 , and iso-C 15:0 . Numerous studies have shown that the major change in fatty acid composition when L. monocytogenes is grown at low temperatures is an increase in the content of anteiso-C 15:0 fatty acid to 65% or more of the total (1,12,23,...

“…We have reported previously (39) that Listeria spp. can be cold adapted by an increased content (30%) of neutral lipids (NL) among total lipids (TL) and an increase in the a-15:0/a-17:0 FA ratio (FAr) of TL, polar lipids (PL), and NL (10-, 10-, and 7-fold, respectively), as well as by an increase in FAr (38) for each NL subclasses 1,2-diglyceride, 1,3-diglyceride and free FA (6-, 5-, and 8-fold, respectively).…”

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confidence: 99%

Coordinated Regulation of Cold-Induced Changes in Fatty Acids with Cardiolipin and Phosphatidylglycerol Composition among Phospholipid Species for the Food Pathogen Listeria monocytogenes

Mastronicolis

Arvanitis

Karaliota

et al. 2008

Self Cite

We present here the structural identification of four phospholipid (Phl) classes in Listeria monocytogenes, the fatty acid (FA) composition for each individual Phl species, and a description of cold-induced FA changes. Cardiolipin (48.5%) and phosphatidylglycerol (18.1%) are dominated by anteiso-FA, and the previously recognized branched FA chain shortening by cold was observed singularly in these Phls. Phosploaminolipid (19.9%) and phosphatidylinositol, (9.1%) are significantly different, containing significant amounts of straightchain FA. These findings are supported by nuclear magnetic resonance analysis.The bacterium Listeria monocytogenes, one of the leading causes of food-borne illness (15), can adapt to cold and salinity (9,10,31,46,53) and can survive even on dust or flakes of organic material (34). Listeria is characterized by Ͼ85% branched-chain fatty acids (FA), anteiso-15:0 (a-15:0) and anteiso-17:0 (a-17:0). Cells grown in the cold (5°C) contain significantly less a-17:0 than those grown at higher temperatures (4,8,37,43,44,57). A cryotolerance element of Listeria is also its ability to use cryoprotectant osmolytes (31), a property shared by other organisms (2, 3, 12, 21, 23). The critical role of odd numbered anteiso-FA in influencing the lower-temperature growth limits has recently been reported (14,19,25). We have reported previously (39) that Listeria spp. can be cold adapted by an increased content (30%) of neutral lipids (NL) among total lipids (TL) and an increase in the a-15:0/a-17:0 FA ratio (FAr) of TL, polar lipids (PL), and NL (10-, 10-, and 7-fold, respectively), as well as by an increase in FAr (38) for each NL subclasses 1,2-diglyceride, 1,3-diglyceride and free FA (6-, 5-, and 8-fold, respectively).This study is a continuation (35, 36) of an investigation for the structural characterization of the major phospholipid (Phl) classes of L. monocytogenes, in order to (i) elucidate the isolation and quantification of each of class (cells at 30°C), (ii) evaluate the cold temperature (5°C) effect on each individual Phl class FA composition, and (iii) confirm the findings by 1 H-nuclear magnetic resonance (NMR) analysis.