scholarly journals The Response of Campylobacter jejuni to Low Temperature Differs from That of Escherichia coli

2009 ◽  
Vol 75 (19) ◽  
pp. 6292-6298 ◽  
Author(s):  
Rebecca-Ayme Hughes ◽  
Kathy Hallett ◽  
Tristan Cogan ◽  
Mike Enser ◽  
Tom Humphrey
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Low Temperature ◽  
Heat Resistance ◽  
Campylobacter Jejuni ◽  
Acid Composition ◽  
Cold Exposure ◽  
E Coli ◽  
K 12

ABSTRACT Human infection with Campylobacter jejuni is often associated with the consumption of foods that have been exposed to both chilling and high temperatures. Despite the public health importance of this pathogen, little is known about the effects of cold exposure on its ability to survive a subsequent heat challenge. This work examined the effect of rapid exposure to chilling, as would occur in poultry processing, on the heat resistance at 56°C of two C. jejuni strains, 11168 and 2097e48, and of Escherichia coli K-12. Unlike E. coli K-12, whose cold-exposed cells showed increased sensitivity to 56°C, such exposure had only a marginal effect on subsequent heat resistance in C. jejuni. This may be explained by the finding that during rapid chilling, unlike E. coli cells, C. jejuni cells are unable to alter their fatty acid composition and do not adapt to cold exposure. However, their unaltered fatty acid composition is more suited to survival when cells are exposed to high temperatures. This hypothesis is supported by the fact that in C. jejuni, the ratio of unsaturated to saturated fatty acids was not significantly different after cold exposure, but it was in E. coli. The low-temperature response of C. jejuni is very different from that of other food-borne pathogens, and this may contribute to its tolerance to further heat stresses.

Advanced Gas Chromatographic–Mass Spectrometric Studies for Identification of the Cellular Octadecenoate Isomers and Changes of Fatty Acid Composition Induced by Ethanol Stress in Escherichia coli and Escherichia coli O157:H7

2007 ◽  
Vol 70 (3) ◽  
pp. 616-622 ◽  
Author(s):  
KUO-LONG KU ◽  
JUI-LONG CHIOU ◽  
FANG-CHI LIU ◽  
ROBIN Y.-Y. CHIOU
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Capillary Column ◽  
Cellular Fatty Acid ◽  
Submerged Cultivation ◽  
Ethanol Stress ◽  
E Coli

Ethanol can be introduced to foods of various origins and is commonly used for surface disinfection. Low concentrations of residual ethanol may provide an opportunity for pathogens to adapt and grow. Change of cellular fatty acid composition is one of adaptation mechanisms enabling bacteria to grow under varied stresses. Since instrumental analyses of bacterial octadecenoate isomers are sophisticated, gas chromatographic analyses of the isomers, namely trans-9-octadecenoate, trans-11-octadecenoate, cis-9-octadecenoate, and cis-11-octadecenoate, and ethanol-induced formation of trans-9-octadecenoate in Escherichia coli and E. coli O157:H7 were intensively investigated. When an HP-1, a nonpolar capillary column, was used for gas chromatographic analyses of 28 authentic bacterial acid methyl esters, resolution was satisfied for all fatty acid components except trans-9-octadecenoate and cis-11-octadecenoate, being overlapped. When the column was replaced by an RTx-2330, a polar capillary column, all of the above-mentioned octadecenoate isomers were resolved. When cells of E. coli and E. coli O157:H7 were harvested after submerged cultivation (30°C, 150 rpm) in tryptic soy broth and tryptic soy broth supplemented with 5% ethanol at early stationary phase and subjected to cellular fatty acid analyses by using an HP-1 and RTx-2330 coupled with a mass detector, 12 fatty acids, i.e., trans-9-octadecenoate, 5 saturated fatty acids, 2 cyclopropane fatty acids and 4 cisunsaturated fatty acids, were identified. Individual fatty acid contents varied depending on nature of fatty acid, strain of E. coli, and supplement of ethanol. As affected by ethanol stress for both E. coli strains, contents of trans-9-octadecenoate increased, whereas contents of cyc-9,10-methylene octadecanoate (cyc-9,10-19:0) decreased significantly (P < 0.05). Apparently, both E. coli strains have rendered necessary fatty acid adaptation to survive and grow under ethanol stress.

The effect of temperature and other growth conditions on the fatty acid composition of Escherichia coli

1981 ◽  
Vol 27 (8) ◽  
pp. 835-840 ◽  
Author(s):  
James T. McGarrity ◽  
John B. Armstrong
Keyword(s):  
Escherichia Coli ◽  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Exponential Growth ◽  
Growth Conditions ◽  
Cyclopropane Fatty Acid ◽  
Cyclopropane Fatty Acids ◽  
K 12

During exponential growth, strain AW405 of Escherichia coli K-12 did not regulate the fatty acid composition of its lipids in response either to temperature or to the addition of NaCl, KCl, or MgCl2 to the medium. Growth was severely restricted at temperatures below 21 °C. Differential scanning calorimetry (DSC) of the isolated lipids from a culture with a typical exponential-phase composition yielded a broad transition, extending from approximately 0 to 33 °C, with a midpoint at 19 °C.During late stages of growth, the fatty acid composition changed. The percentage of palmitic acid increased and cyclopropane fatty acids replaced some of the equivalent unsaturated fatty acids. The increase in palmitate seemed largely independent of growth conditions, whereas the increase in the cyclopropane fatty acids was stimulated by the addition of salts or sucrose. Cultures grown in the presence of sucrose also had higher cyclopropane fatty acid levels during exponential growth. DSC of lipids from a sucrose culture, in which the compositional changes were most pronounced, yielded a much narrower transition with a midpoint at 27 °C.

Effect of noradrenaline chronic administration on brown fat phospholipids

1988 ◽  
Vol 8 (5) ◽  
pp. 465-469 ◽  
Author(s):  
Gérard Mory ◽  
Myriam Gawer ◽  
Jean-Claude Kader
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Brown Adipose Tissue ◽  
Acid Composition ◽  
Cold Exposure ◽  
Chronic Administration ◽  
Sympathetic Tone ◽  
Brown Fat ◽  
Brown Adipose

Chronic cold exposure of rats (9 days at 5°C) induces an alteration of the fatty acid composition of phospholipids in brown adipose tissue. The alteration is due to an increase of the unsaturation degree of these lipids. The phenomenon can be reproduced by 10−7 mole. h−1 administration of noradrenaline for 9 days in rats kept at 25°C. Thus, phospholipid alteration in brown fat of cold exposed rats is most probably a consequence of the increase of sympathetic tone which occurs in this tissue during exposure to cold.

Effect of fabA and desA Mediated Low Temperature Adaption on Shewanella putrefaciens via Regulation of Unsaturated Fatty Acid Metabolism

2019 ◽  
Vol 11 (10) ◽  
pp. 1430-1437
Author(s):  
Li Chen ◽  
Shengping Yang ◽  
Yunfang Qian ◽  
Jing Xie
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Low Temperature ◽  
Acid Composition ◽  
Fatty Acid Metabolism ◽  
Unsaturated Fatty Acid ◽  
Acid Metabolism ◽  
Shewanella Putrefaciens ◽  
Spoilage Bacteria ◽  
Temperature Environment

Shewanella putrefaciensis a kind of spoilage bacteria in low temperature chilled aquatic products, which seriously threats human health and aquaculture. The fatty acid composition of S. putrefaciens cell membranes has been shown to be involved in adaption of bacteria to various environments. However, the specific fatty acid metabolism of S. putrefaciens to the low temperature environment remains unknown. In this study, the growth of S. putrefaciens, the response of fatty acid composition to low temperature production, and the differential expression and synthesis of enzymes related to unsaturated fatty acid synthesis were investigated by lack of fabA and desA in S. putrefaciens. Results showed that loss of fabA and desA suppressed the growth of S. putrefaciens and reduced unsaturated fatty acid contents at low temperature. In addition, the upregulation of fabA, but not desA resulted in accumulation of unsaturated fatty acid. Up-regulations of fabA and desA both resulted in promotion of GPR41 and Retn gene and protein expressions. These results demonstrated that the deletions of fabA and desA resulted in reduction of unsaturated fatty acid and key downstream genes of fatty acid metabolism, which suggested that unsaturated fatty acid was involved in the adaptations of fabA and desA-mediated S. putrefaciens to the low temperature environment. These results provided a tentative mechanism of the synthesis of unsaturated fatty acids in S. putrefaciens under low temperature conditions.

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