Saito Holly E, Harp John R, Fozo Elizabeth M
Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA.
Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
Appl Environ Microbiol. 2017 Dec 15;84(1). doi: 10.1128/AEM.01633-17. Print 2018 Jan 1.
is a commensal of the human gastrointestinal tract that can persist in the external environment and is a leading cause of hospital-acquired infections. Given its diverse habitats, the organism has developed numerous strategies to survive a multitude of environmental conditions. Previous studies have demonstrated that will incorporate fatty acids from bile and serum into its membrane, resulting in an induced tolerance to membrane-damaging agents. To discern whether all fatty acids induce membrane stress protection, we examined how responded to individually supplied fatty acids. readily incorporated fatty acids 14 to 18 carbons in length into its membrane but poorly incorporated fatty acids shorter or longer than this length. Supplementation with saturated fatty acids tended to increase generation time and lead to altered cellular morphology in most cases. Further, exogenously supplied saturated fatty acids did not induce tolerance to the membrane-damaging antibiotic daptomycin. Supplementation with unsaturated fatty acids produced variable growth effects, with some impacting generation time and morphology. Exogenously supplied unsaturated fatty acids that are normally produced by and those that are found in bile or serum could restore growth in the presence of a fatty acid biosynthetic inhibitor. However, only the eukaryote-derived fatty acids oleic acid and linoleic acid provided protection from daptomycin. Thus, exogenous fatty acids do not lead to a common physiological effect on The organism responds uniquely to each, and only host-derived fatty acids induce membrane protection. is a commonly acquired hospital infectious agent with resistance to many antibiotics, including those that target its cellular membrane. We previously demonstrated that will incorporate fatty acids found in human fluids, like serum, into its cellular membrane, thereby altering its membrane composition. In turn, the organism is better able to survive membrane-damaging agents, including the antibiotic daptomycin. We examined fatty acids commonly found in serum and those normally produced by to determine which fatty acids can induce protection from membrane damage. Supplementation with individual fatty acids produced a myriad of different effects on cellular growth, morphology, and stress response. However, only host-derived unsaturated fatty acids provided stress protection. Future studies are aimed at understanding how these specific fatty acids induce protection from membrane damage.
是人类胃肠道的共生菌，可在外部环境中存活，是医院获得性感染的主要原因。鉴于其多样的生存环境，该生物体已发展出多种策略来在多种环境条件下生存。先前的研究表明，会将胆汁和血清中的脂肪酸纳入其细胞膜，从而产生对膜损伤剂的诱导耐受性。为了确定是否所有脂肪酸都会诱导膜应激保护，我们研究了对单独供应的脂肪酸的反应。很容易将长度为14至18个碳的脂肪酸纳入其细胞膜，但对于短于或长于此长度的脂肪酸则纳入能力较差。补充饱和脂肪酸往往会延长代时，并在大多数情况下导致细胞形态改变。此外，外源供应的饱和脂肪酸不会诱导对膜损伤抗生素达托霉素的耐受性。补充不饱和脂肪酸产生了可变的生长效应，有些影响代时和形态。外源供应的通常由产生的不饱和脂肪酸以及胆汁或血清中发现的不饱和脂肪酸可以在脂肪酸生物合成抑制剂存在的情况下恢复生长。然而，只有真核生物来源的脂肪酸油酸和亚油酸提供了对达托霉素的保护。因此，外源脂肪酸不会对产生共同的生理效应。该生物体对每种脂肪酸的反应都独特，只有宿主来源的脂肪酸会诱导膜保护。是一种常见的医院感染病原体，对许多抗生素具有抗性，包括那些针对其细胞膜的抗生素。我们先前证明，会将人体液（如血清）中发现的脂肪酸纳入其细胞膜，从而改变其膜组成。反过来，该生物体能够更好地在包括抗生素达托霉素在内的膜损伤剂中存活。我们研究了血清中常见的脂肪酸以及通常由产生的脂肪酸，以确定哪些脂肪酸可以诱导免受膜损伤的保护。补充单个脂肪酸对细胞生长、形态和应激反应产生了无数不同的影响。然而，只有宿主来源的不饱和脂肪酸提供了应激保护。未来的研究旨在了解这些特定脂肪酸如何诱导免受膜损伤的保护。
