The extraction of cell walls of Pseudomonas aeruginosa with aqueous phenol. Material from the phenol layer.
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ABSTRACT:
SUBMITTER: Clarke K
PROVIDER: S-EPMC1198375 | biostudies-other | 1967 Nov
REPOSITORIES: biostudies-other
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Project description:1. The insoluble residue and material present in the aqueous layers resulting from treatment of cell walls of Pseudomonas aeruginosa with aqueous phenol were examined. 2. The products (fractions AqI and AqII) isolated from the aqueous layers from the first and second extractions respectively account for approx. 25% and 12% of the cell wall and consist of both lipopolysaccharide and muropeptide. 3. The lipid part of the lipopolysaccharide is qualitatively similar to the corresponding material (lipid A) from other Gram-negative organisms, as is the polysaccharide part. 4. The insoluble residue (fraction R) contains sacculi, which also occur in fraction AqII. On hydrolysis, the sacculi yield glucosamine, muramic acid, alanine, glutamic acid and 2,6-diaminopimelic acid, together with small amounts of lysine, and they are therefore similar to the murein sacculi of other Gram-negative organisms. Fraction R also contains substantial amounts of protein, which differs from that obtained from the phenol layer. 5. The possible association or aggregation of lipopolysaccharide, murein and murein sacculi is discussed.
| S-EPMC1198376 | biostudies-other
Project description:1. Cell walls of Pseudomonas aeruginosa were prepared and analysed. 2. Separate preparations were found to be reproducible, e.g. the phosphorus contents of all batches lay in the range 2.0-2.1%. 3. Ninhydrin-positive compounds in hydrolysates accounted for 43-46% of the cell wall and 79-87% of the nitrogen of the cell wall. Examination of the results for individual ninhydrin-positive compounds showed that 5-15% of the cell wall was murein and about 30% protein. 4. Trypsin treatment of crude cell-wall preparations preferentially liberated arginine, lysine and leucine, but it was not clear whether these arose from cell-wall or cytoplasmic proteins.
| S-EPMC1198374 | biostudies-other
Project description:Herein, a conductive boron-doped nanodiamond (BDND) particle is prepared as an electrode material for an aqueous electric double-layer capacitor with high power and energy densities. The BDND is obtained by depositing a boron-doped diamond (BDD) on a nanodiamond particle substrate with a primary particle size of 4.7 nm via microwave plasma-assisted chemical vapor deposition, followed by heat treatment in air. The BDND comprises BDD and sp2 carbon components, and exhibits a conductivity above 10-2 S cm-1 and a specific surface area of 650 m2 g-1. Cyclic voltammetry measurements recorded in 1 M H2SO4 at a BDND electrode in a two-electrode system shows a capacitance of 15.1 F g-1 and a wide potential window (cell voltage) of 1.8 V, which is much larger than that obtained at an activated carbon electrode, i.e., 0.8 V. Furthermore, the cell voltage of the BDND electrode reaches 2.8 V when using saturated NaClO4 as electrolyte. The energy and power densities per unit weight of the BDND for charging-discharging in 1 M H2SO4 at the BDND electrode cell are 10 Wh kg-1 and 104 W kg-1, respectively, and the energy and power densities per unit volume of the BDND layer are 3-4 mWh cm-3 and 10 W cm-3, respectively. Therefore, the BDND is a promising candidate for the development of a compact aqueous EDLC device with high energy and power densities.
| S-EPMC6882838 | biostudies-literature
Project description:In recent years, on account of their excellent mechanical properties, composite materials (made of epoxy-bonded carbon, glass, or aramid fibers) have been used to reinforce masonry walls against in-plane actions. These materials have proven to be an effective solution for the strengthening of unreinforced masonry (URM) walls. Lately, research has shifted to the study of different types of fibers to avoid the use of epoxy adhesives, whose long-term behavior and compatibility with masonry are poor. This paper describes an experimental program that investigated the behavior of URM shear walls strengthened with two types of commercially available polypropylene products: short fibers (fiber length = 12 mm) and polypropylene nets. This investigation aimed to evaluate the influence of polypropylene reinforcement, embedded into an inorganic matrix, in terms of the improvement of the lateral load-carrying capacity, failure mechanism, ductility, and energy dissipation capacity of URM wall panels, where nine walls were subjected to in-plane loads using a racking test setup. The study showed that using two layers of polypropylene fibers embedded into a cementitious matrix greatly increased the in-plane load capacity of the brickwork masonry. On the other hand, the test results indicated that polypropylene nets, used as a repair method for cracked shear walls, cannot improve the structural performance of the walls.
| S-EPMC7321489 | biostudies-literature
Project description:1. Walls of certain Gram-positive bacteria dissolved on incubation with dilute aqueous NN-dimethylhydrazine in the presence of air, by a reaction that probably involves free radicals. 2. Under the conditions described, the soluble products from the peptidoglycan were almost all non-diffusible. After brief incubation of walls of some organisms with reagent, part of the peptidoglycan component was obtained as a high-molecular-weight gel, the viscosity of which was rapidly decreased by incubation with lysozyme. 3. The extent to which peptidoglycan dissolved varied with different organisms, depending possibly on the extent of cross-linking, but the nature of the bonds that were destroyed has not been established. 4. Teichoic acids and polysaccharides were solubilized by this treatment and could be isolated in high overall yield. 5. The procedure is valuable in the examination of the distribution of heteropolymers in walls, and has been used to show that the polysaccharide present in walls of Lactobacillus arabinosus 17-5 is phosphorylated and may account for 20% of the total phosphate of the wall.
| S-EPMC1184618 | biostudies-other
Project description:Accurate and reliable analysis of gene expression depends on the extraction of pure and high-quality RNA. However, while the conventional phenol-chloroform RNA extraction is preferable over silica-based columns, particularly when cost is a concern or higher RNA yield is desired, it can result in significant RNA contamination. Contaminants including excess phenol, chloroform, or salts, can have significant impacts on downstream applications, including RNA quantification and reverse transcription, that can skew data collection and interpretation. To overcome the issue of RNA contamination in the conventional phenol-chloroform based RNA extraction method, we have optimized the protocol by adding one chloroform extraction step, and several RNA washing steps. Importantly, RNA quality and purity and accuracy in the quantification of RNA concentration were significantly improved with the modified protocol, resulting in reliable data collection and interpretation in downstream gene expression analysis. •Our protocol is customized by the addition of a second chloroform extraction step. Chloroform is carefully pipetted so as to not disturb the interphase layer. Any contaminants accidentally removed from interphase will be present in subsequent steps and can result in RNA contaminated with protein or phenol. The additional chloroform step increases RNA purity.•Additionally, the addition of 2 additional ethanol washes, initially intended to remove any residual salts from the isopropanol RNA precipitation step, also removed residual phenol contamination, enhancing RNA purity.•In summary, these modifications serve to enhance not only the purity of the RNA but, also increase the accuracy and reliability of RNA quantification.
| S-EPMC6031757 | biostudies-literature
Project description:Brief heating of Bacillus Licheniformis cell walls at 100 degrees C in aqueous buffers of pH3.0-4.0 removes some polymers but not others from the mucopeptides. For example, relatively undegraded teichuronic acid can be extracted at 100 degrees C in 20min at pH3.0 whereas the teichoic acids are not removed. Similar specificity can be shown with walls from three other species of micro-organism.
| S-EPMC1177511 | biostudies-other
Project description:BACKGROUND: The respiratory tract epithelium is a critical environmental interface that regulates inflammation. In chronic infectious airway diseases, pathogens may permanently colonize normally sterile luminal environments. Host-pathogen interactions determine the intensity of inflammation and thus, rates of tissue injury. Although many cells become refractory to stimulation by pathogen products, it is unknown whether the airway epithelium becomes either tolerant or hypersensitive in the setting of chronic infection. Our goals were to characterize the response of well-differentiated primary human tracheobronchial epithelial cells to Pseudomonas aeruginosa, to understand whether repeated exposure induced tolerance and, if so, to explore the mechanism(s). METHODS: The apical surface of well-differentiated primary human tracheobronchial epithelial cell cultures was repetitively challenged with Pseudomonas aeruginosa culture filtrates or the bacterial media control. Toxicity, cytokine production, signal transduction events and specific effects of dominant negative forms of signaling molecules were examined. Additional experiments included using IL-1beta and TNFalpha as challenge agents, and performing comparative studies with a novel airway epithelial cell line. RESULTS: An initial challenge of the apical surface of polarized human airway epithelial cells with Pseudomonas aeruginosa culture filtrates induced phosphorylation of IRAK1, JNK, p38, and ERK, caused degradation of IkappaBalpha, generation of NF-kappaB and AP-1 transcription factor activity, and resulted in IL-8 secretion, consistent with activation of the Toll-like receptor signal transduction pathway. These responses were strongly attenuated following a second Pseudomonas aeruginosa, or IL-1beta, but not TNFalpha, challenge. Tolerance was associated with decreased IRAK1 protein content and kinase activity and dominant negative IRAK1 inhibited Pseudomonas aeruginosa--stimulated NF-kappaB transcriptional activity. CONCLUSION: The airway epithelial cell response to Pseudomonas aeruginosa entails adaptation and tolerance likely mediated, in part, by down-regulation of IRAK1.
| S-EPMC1087506 | biostudies-literature
Project description:Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids. However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development thereafter, a bacteriophage capable of superinfecting and lysing the P. aeruginosa parent strain was detected in the fluid effluent from the biofilm. The bacteriophage implicated in biofilm killing was closely related to the filamentous phage Pf1 and existed as a prophage within the genome of P. aeruginosa. We propose that prophage-mediated cell death is an important mechanism of differentiation inside microcolonies that facilitates dispersal of a subpopulation of surviving cells.
| S-EPMC165772 | biostudies-literature
Project description:PTex is a protocol to purify UV-cross-linked ribonucleoproteins (RNPs) in an unbiased and sequence-independent fashion. Total RNA from HEK293 cells was analysed by RNASeq from whole cell lysates as well as after purification of RNPs.
2019-02-02 | GSE113655 | GEO