Alteration of the phospho- or neutral lipid content and fatty acid composition in Listeria monocytogenes due to acid adaptation mechanisms for hydrochloric, acetic and lactic acids at pH 5.5 or benzoic acid at neutral pH

This study provides a first approach to observe the effects on Listeria monocytogenes of cellular exposure to acid stress at low or neutral pH, notably how phospho- or neutral lipids are involved in this mechanism, besides the fatty acid profile alteration. A thorough investigation of the composition of polar and neutral lipids from L. monocytogenes grown at pH 5.5 in presence of hydrochloric, acetic and lactic acids, or at neutral pH 7.3 in presence of benzoic acid, is described relative to cells grown in acid-free medium. The results showed that only low pH values enhance the antimicrobial activity of an acid. We suggest that, irrespective of pH, the acid adaptation response will lead to a similar alteration in fatty acid composition [decreasing the ratio of branched chain/saturated straight fatty acids of total lipids], mainly originating from the neutral lipid class of adapted cultures. Acid adaptation in L. monocytogenes was correlated with a decrease in total lipid phosphorus and, with the exception of cells adapted to benzoic acid, this change in the amount of phosphorus reflected a higher content of the neutral lipid class. Upon acetic or benzoic acid stress the lipid phosphorus proportion was analysed in the main phospholipids present: cardiolipin, phosphatidylglycerol, phosphoaminolipid and phosphatidylinositol. Interestingly only benzoic acid had a dramatic effect on the relative quantities of these four phospholipids

Generation of polyclonal antibody with high avidity to rosuvastatin and its use in development of highly sensitive ELISA for determination of rosuvastatin in plasma

In this study, a polyclonal antibody with high avidity and specificity to the potent hypocholesterolaemic agent rosuvastatin (ROS) has been prepared and used in the development of highly sensitive enzyme-linked immunosorbent assay (ELISA) for determination of ROS in plasma. ROS was coupled to keyhole limpt hemocyanin (KLH) and bovine serum albumin (BSA) using carbodiimide reagent. ROS-KLH conjugate was used for immunization of female 8-weeks old New Zealand white rabbits. The immune response of the rabbits was monitored by direct ELISA using ROS-BSA immobilized onto microwell plates as a solid phase. The rabbit that showed the highest antibody titer and avidity to ROS was scarified and its sera were collected. The IgG fraction was isolated and purified by avidity chromatography on protein A column. The purified antibody showed high avidity to ROS; IC50 = 0.4 ng/ml. The specificity of the antibody for ROS was evaluated by indirect ELISA using various competitors from the ROS-structural analogues and the therapeutic agents used with ROS in a combination therapy. The proposed ELISA involved a competitive binding reaction between ROS, in plasma sample, and the immobilized ROS-BSA for the binding sites on a limited amount of the anti-ROS antibody. The bound anti-ROS antibody was quantified with horseradish peroxidase-labeled second anti-rabbit IgG antibody (HRP-IgG) and 3,3',5,5'-tetramethylbenzidine (TMB) as a substrate for the peroxidase enzyme. The concentration of ROS in the sample was quantified by its ability to inhibit the binding of the anti-ROS antibody to the immobilized ROS-BSA and subsequently the color intensity in the assay wells. The assay enabled the determination of ROS in plasma at concentrations as low as 40 pg/ml

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

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 straight-chain FA. These findings are supported by nuclear magnetic resonance analysis

Structural diversity and possible functional roles of free fatty acids of the novel soil isolate Streptomyces sp. NP10

Herein, a novel soil bacterium Streptomyces sp. NP10 able to grow outside usual streptomycetes optimum conditions (e.g., at 4 A degrees C, pH 9 and high NaCl concentration), exhibiting atypical hemolytic, DNAse, and cellulolytic activities, is described. This strain produces and excretes into the growth medium large amounts of free long-chain fatty acids (FAs). A concurrent lipidomics study revealed a large structural diversity of FAs with over 50 different n- and branched-chain, (un)saturated, and cyclopropane FAs (C-7-C-30) produced by this strain. Two of these, i-17:0cy9-10 and a-18:0cy9-10, represent new natural products and the first ever identified branched cyclopropane FAs. Both free and bound lipid profiles of Streptomyces sp. NP10 were dominated by saturated branched chain FAs (i-14:0, a-15:0, and i-16:0). Although these free FAs showed only a moderate antimicrobial activity, our results suggest that they could have an ecophysiological role in interspecies signaling with another soil microorganism Pseudomonas aeruginosa. This work represents the first comprehensive report on the structural diversity and complexity of the free FA pool in Streptomyces. A naturally occurring streptomycete, such as Streptomyces sp. NP10, which secretes significant amounts of free long-chain FAs (non-cytotoxic) into the medium, could be useful in microbial biodiesel production.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3430