Diese Arbeit wurde durch Mittel der National Institutes of Health und der Mukoviszidose-Stiftung unterstützt.

1. Vorbereitung der Bakterien für die LPS-Extraktion <ol><li> Starten Sie eine Übernachtkultur in 5 ml Luria Broth (LB), die mit Antibiotika bei Bedarf ergänzt. Kultur wachsen über Nacht (12-18 Stunden) in einem Schüttelinkubator bei 37 ° C und 200 Umdrehungen pro Minute. </li><li> Verdünnen Sie die Kultur im Verhältnis 1:10 mit LB und nehmen eine OD 600 Lektüre in einem Spektralphotometer. Basierend auf der OD 600 Lektüre, machen Sie eine 1,5 ml Suspension aus Ihrem Bakterien auf eine OD 600 von 0,5. </li><li> Pellet die Bakterien in einer Mikrozentrifuge bei 10.600 x g für 10 Minuten. Entfernen und den Überstand verwerfen. Das Pellet kann bei -20 ° C gelagert werden, wenn LPS nicht geht ist, sofort extrahiert werden. </li></ol> 2. Extraktion von LPS <ol><li> Zuerst bereiten 2x SDS-Puffer. Einen 50 ml Lösung von 4% β-Mercaptoethanol (BME), 4% SDS und 20% Glycerin in 0,1 M Tris-HCl, pH 6,8. Fügen Sie eine Prise Bromphenolblau, um die Lösung zu färben. Machen Sie einen 1x SDS-Puffer Lager durch Verdünnung von 2x Stock 1:1 in sterilem destilliertem H 2 O. Dies kann bei Raumtemperatur gelagert werden. </li><li> Machen Sie drei separate 10 mg / ml Lösung von DNase I, RNase-und Proteinase K in sterilem destilliertem H 2 O. </li><li> Resuspendieren pelletierten Bakterien aus Schritt 1.3 in 200 ul 1x SDS-Puffer. Sie sicher, dass das Pellet vollständig durch Pipettieren der Lösung langsam auf und ab resuspendiert. Nicht vortexen. </li><li> Kochen suspendierter Bakterien in einem Wasserbad für 15 Minuten. Lassen Sie die Lösung bei Raumtemperatur für 15 Minuten abkühlen. </li><li> 5 l der beiden DNase I und RNase-Lösungen in 2.2 vorbereitet. Inkubieren der Proben bei 37 ° C für 30 Minuten. * Dieser Schritt ist optional, es gibt minimale Unterschied in der Qualität von LPS zwischen Nuklease-behandelten und unbehandelten Proben. </li><li> In 10 ul der Proteinase K-Lösung in 2.2 vorbereitet. Inkubieren der Proben bei 59 ° C für 3 Stunden. Dieser Schritt kann über Nacht durchgeführt werden, wenn es Zeitdruck sind. </li><li> Zu jeder Probe add 200 pl eiskaltem Tris-gesättigtem Phenol (Wasser gesättigtem Phenol kann als Ersatz verwendet werden, wenn Tris-gesättigtem Phenol steht nicht zur Verfügung). Stellen Sie sicher, die Kappen an die Rohre dicht verschlossen sind, und Vortex jede Probe für etwa 5 bis 10 Sekunden. </li><li> Inkubieren der Proben bei 65 ° C für 15 Minuten, gelegentlich Vortexen. Nach Inkubation bei Raumtemperatur abkühlen lassen, dann fügen Sie 1 mL bei Raumtemperatur Diethylether zu jeder Probe und Vortex für 5 bis 10 Sekunden. Achten Sie darauf, Griff Äther in einem Abzug durchführen, da es flüchtig ist. </li><li> Zentrifugation der Proben bei 20.600 × g für 10 Minuten. Entfernen Sie vorsichtig die Proben aus der Zentrifuge und extrahieren Sie die untere blaue Schicht. Achten Sie darauf, die obere, klare Schicht zu vermeiden. Zurücklassung einer kleinen Menge des blauen Schicht ist bevorzugt, um eine Kontamination mit der oberen Schicht. </li><li> Extrahieren Sie erneut die Proben durch Wiederholen der Schritte von 2,7 bis 2,9. Zwei Extraktionen sind in der Regel ausreichend. Wenn die Proben bedeckt erscheinen, kann mehr sein Extraktionen performed. Zugabe von 200 ul 2x SDS-Puffer zu jedem der extrahierten Proben vor der Trennung durch SDS-PAGE. Die Proben können bei 8% -15% SDS-Polyacrylamid-Gelen laufen gelassen werden. Fünf bis fünfzehn ul von LPS unter Verwendung dieser Methode ist in der Regel ausreichend für die Visualisierung. </li></ol> 3. Repräsentative Ergebnisse LPS Proben wie oben hergestellt visualisiert werden kann durch direkte Färbung nach der Trennung auf SDS-PAGE unter Verwendung eines Standard-Silber-Färbung Protokoll oder ein im Handel erhältliches LPS-Färbekit. Alternativ kann LPS auf einem Polyacrylamidgel getrennt auf eine Nitrocellulosemembran übertragen werden und Western-Immunoblotting unter Verwendung LPS-spezifischen Anti-Seren. Aus diesem Protokoll verwendeten wir die Pro-Q Smaragd 300 Lipopolysaccharid Gel Stain Kit (Molecular Probes), und folgte den Anweisungen des Herstellers. Dargestellt in Abbildung 1 ist ein Pro-Q 300 Smaragd gefärbten 12% SDS-Polyacrylamidgel. Jede Spur enthält 15 ul LPS aus unterschiedlichen vorbereitetschiedenen Stämme von Burkholderia dolosa isoliert aus Sputum-Proben von Patienten mit zystischer Fibrose. Verschiedene Streifen LPS Leitermuster, reflektierende unterschiedlicher Zahlen O-Antigen sich wiederholenden Einheiten, die an Kernoligosaccharid ergeben sich unter Verwendung dieses Verfahrens, zum Beispiel, müssen die Proben in Spur 1 und 6 ähnliche Bandenmuster miteinander (Kasten in rot). <img alt="1" src="/files/ftp_upload/3916/3916fig1.jpg" /> Abbildung 1. Pro-Q Smaragd 300 gebeizt LPS von Burkholderia dolosa klinischen Isolaten. LPS aus sieben B. dolosa Stämme aus einem Ausbruch bei Mukoviszidose-Patienten isoliert wurden, wie in diesem Protokoll beschrieben. Fünfzehn ul wurden auf einem 12% SDS-Polyacrylamid-Gel, und gefärbt mit Pro-Q Smaragd 300 getrennt, pro Anweisungen des Herstellers. LPS-Kern einen Pfeil gekennzeichnet, und LPS zu ähnlichen Bandenmuster von O-Antigen Wiederholungen sind in rot eingerahmt. M = Molekulargewichtsmarker.

<ol>
	<li>Raetz, C. R., Whitfield, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipopolysaccharide+endotoxins.">Lipopolysaccharide endotoxins.</a> Annu. Rev. Biochem. 71, 635-700 (2002).</li><li>Valvano, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Export+of+O-specific+lipopolysaccharide.">Export of O-specific lipopolysaccharide.</a> Front. Biosci. 8, 452-471 (2003).</li><li>Pier, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+aeruginosa+lipopolysaccharide:+a+major+virulence+factor,+initiator+of+inflammation+and+target+for+effective+immunity.">Pseudomonas aeruginosa lipopolysaccharide: a major virulence factor, initiator of inflammation and target for effective immunity.</a> Int. J. Med. Microbiol. 297, 277-295 (2007).</li><li>Freudenberg, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+lipopolysaccharide+susceptibility+in+the+innate+immune+response+to+Salmonella+typhimurium+infection:+LPS,+a+primary+target+for+recognition+of+Gram-negative+bacteria.">Role of lipopolysaccharide susceptibility in the innate immune response to Salmonella typhimurium infection: LPS, a primary target for recognition of Gram-negative bacteria.</a> Microbes Infect. 3, 1213-1222 (2001).</li><li>Jann, K., Jann, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polysaccharide+antigens+of+Escherichia+coli.">Polysaccharide antigens of Escherichia coli.</a> Rev. Infect. Dis. 9, S517-S526 (1987).</li><li>McCallum, K. L., Schoenhals, G., Laakso, D., Clarke, B., Whitfield, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-molecular-weight+fraction+of+smooth+lipopolysaccharide+in+Klebsiella+serotype+O1:K20+contains+a+unique+O-antigen+epitope+and+determines+resistance+to+nonspecific+serum+killing.">A high-molecular-weight fraction of smooth lipopolysaccharide in Klebsiella serotype O1:K20 contains a unique O-antigen epitope and determines resistance to nonspecific serum killing.</a> Infect. Immun. 57, 3816-3822 (1989).</li><li>Hancock, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+aeruginosa+isolates+from+patients+with+cystic+fibrosis:+a+class+of+serum-sensitive,+nontypable+strains+deficient+in+lipopolysaccharide+O+side+chains.">Pseudomonas aeruginosa isolates from patients with cystic fibrosis: a class of serum-sensitive, nontypable strains deficient in lipopolysaccharide O side chains.</a> Infect. Immun. 42, 170-177 (1983).</li><li>Gupta, S. K., Masinick, S., Garrett, M., Hazlett, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+aeruginosa+lipopolysaccharide+binds+galectin-3+and+other+human+corneal+epithelial+proteins.">Pseudomonas aeruginosa lipopolysaccharide binds galectin-3 and other human corneal epithelial proteins.</a> Infect. Immun. 65, 2747-2753 (1997).</li><li>Hitchcock, P. J., Brown, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphological+heterogeneity+among+Salmonella+lipopolysaccharide+chemotypes+in+silver-stained+polyacrylamide+gels.">Morphological heterogeneity among Salmonella lipopolysaccharide chemotypes in silver-stained polyacrylamide gels.</a> J. Bacteriol. 154, 269-277 (1983).</li><li>Westphal, O., Jann, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+lipopolysaccharides.">Bacterial lipopolysaccharides.</a> Methods Carbohyr. Chem. 5, 83 (1965).</li><li>Lieberman, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parallel+bacterial+evolution+within+multiple+patients+ties+novel+genes+to+pathogenesis.">Parallel bacterial evolution within multiple patients ties novel genes to pathogenesis.</a> Nat Genet. , (2011).</li></ol>

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Wir haben ein Verfahren zur Reinigung von LPS von anderen zellulären Komponenten, einschließlich Nukleinsäuren und Proteinen beschrieben. Diese Methode bietet eine hohe Qualität LPS, die in einer Reihe von verschiedenen Visualisierungsmethoden, einschließlich des Kohlenhydrat-Färbung der SDS-PAGE-Gelen, wie in 1 gezeigt ist, verwendet werden kann. Dieses Verfahren kann verwendet werden, um LPS aus einer Vielzahl von Stämmen Serotyp, unter Verwendung spezifischer Antiseren, oder um eine Verwandtschaft zwischen den...

<table border="1"><tbody><tr><td> Name des Reagenzes </td><td> Firma </td><td> Katalog-Nummer </td></tr><tr><td> DNase I rekombinanten, RNase-frei </td><td> Roche </td><td> 04716728001 </td></tr><tr><td> RNase A </td><td> Roche </td><td> 10109169001 </td></tr><tr><td> Proteinase K </td><td> Fischer </td><td> BP1700 </td></tr><tr><td> Tris-gesättigtem Phenol </td><td> Fischer </td><td> BP1750-100 </td></tr><tr><td> Diethylether </td><td> Thomas Scientific </td><td> C313K31 </td></tr><tr><td> Pro-Q Smaragd 300 Lipopolysaccharid Gel Stain Kit </td><td> Molecular Probes </td><td> P20495 </td></tr></tbody></table>

purification and visualization of lipopolysaccharide from gram-negative bacteria by hot aqueous-phenol extraction

Lipopolysaccharid (LPS) ist ein wichtiger Bestandteil von Gram-negativen bakteriellen äußeren Membranen. Es ist eine dreigliedrige Molekül, das aus Lipid A, das in der äußeren Membran eingebettet ist, ein Kern-Oligosaccharid und Wiederholen der O-Antigen-Einheiten, die nach außen erstrecken sich von der Oberfläche der Zelle 1, 2. LPS ist ein Molekül, das immundominante wichtig für die Virulenz und Pathogenese vieler Bakterienarten, darunter Pseudomonas aeruginosa, Salmonella-Arten, und Escherichia coli 3-5, und Unterschiede in der LPS O-Antigen-Zusammensetzung bilden die Grundlage für die Serotypisierung der Stämme. LPS wird in Anlage beteiligten Zellen zu Beginn der Infektion Host und bietet Schutz vor Komplement-vermittelte Tötung; Stämme, die LPS fehlt, gedämpft werden kann für die Virulenz 6-8. Aus diesen Gründen ist es wichtig, LPS visualisieren, insbesondere aus klinischen Isolaten. Visualisierung von LPS Bandenmuster und Erkennung durch spezifische einntibodies können nützliche Werkzeuge sein, um Stamm-Linien zu identifizieren und verschiedenen Mutanten zu charakterisieren. In diesem Bericht beschreiben wir eine heiße wässrige Phenol-Verfahren zur Isolierung und Reinigung von LPS aus Gram-negativen bakteriellen Zellen. Dieses Protokoll ermöglicht die Extraktion von LPS von Nukleinsäuren und Proteinen, die mit Visualisierung von LPS, die mit kürzeren, weniger intensiv Extraktionsverfahren 9 erfolgt stören können. LPS diese Weise hergestellten durch Natriumdodecylsulfat (SDS)-Polyacrylamid-Gelelektrophorese (PAGE) und gefärbt direkt unter Verwendung von Kohlenhydrat / Glykoprotein Flecken oder Standard-Silberfärbung Verfahren getrennt werden können. Viele Anti-Seren gegen LPS Antikörper enthalten, dass mit der äußeren Membran-Proteine ​​oder andere antigene Ziele, kann ein Hindernis für kreuzreagieren Reaktivität nach Western-Immunoblot-SDS-PAGE getrennt Zelllysat beobachtet. Protease-Behandlung von Zelllysat allein ist nicht immer ein wirksames Mittel zur Beseitigung dieserHintergrund der Nutzung dieser oder andere Visualisierungs-Methoden. Ferner kann umfangreiche Proteasebehandlung in einem Versuch, dieses Objekt zu entfernen, schlechter Qualität LPS, die nicht gut von einem der vorgenannten Verfahren gelöst führen. Aus diesen Gründen glauben wir, dass das folgende Protokoll, aus Westpahl Jann und 10 angepasst, ideal für die LPS-Extraktion ist.

Watch this Scientific Journal Video about Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction at JoVE.com

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction

Wir beschreiben ein modifiziertes heißen wässrigen-Phenolextraktion Verfahren zum Reinigen von Lipopolysaccharid (LPS) von Gram-negativen Bakterien. Sobald extrahiert wurden, kann die LPS anschließend durch SDS-PAGE analysiert und visualisiert werden durch direkte Färbung oder Western-Immunoblot-.

Reinigung und Visualisierung von Lipopolysaccharid aus Gram-negativen Bakterien durch heiße wäßrige-Phenol-Extraktion

Lipopolysaccharide (LPS)  is a major component of Gram-negative bacterial outer membranes. It is a tripartite molecule consisting of  lipid A, which is ...

purification-visualization-lipopolysaccharide-from-gram-negative

Research

JoVE Journal

Immunology and Infection

35.0K Aufrufe.  University of Virginia Health System. Wir beschreiben ein modifiziertes heißen wässrigen-Phenolextraktion Verfahren zum Reinigen von Lipopolysaccharid (LPS) von Gram-negativen Bakterien. Sobald extrahiert wurden, kann die LPS anschließend durch SDS-PAGE analysiert und visualisiert werden durch direkte Färbung oder Western-Immunoblot-.

Serie: Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS can be subdivided into three domains: the distal O-polysaccharide, a core oligosaccharide, and the lipid A domain consisting of a lipid A molecular species and 3-deoxy-D-manno-oct-2-ulosonic acid residues (Kdo). The lipid A domain is the only component essential for bacterial cell survival. Following its synthesis, lipid A is chemically modified in response to environmental stresses such as pH or temperature, to promote resistance to antibiotic compounds, and to evade recognition by mediators of the host innate immune response. The following protocol details the small- and large-scale isolation of lipid A from gram-negative bacteria. Isolated material is then chemically characterized by thin layer chromatography (TLC) or mass-spectrometry (MS). In addition to matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS, we also describe tandem MS protocols for analyzing lipid A molecular species using electrospray ionization (ESI) coupled to collision induced dissociation (CID) and newly employed ultraviolet photodissociation (UVPD) methods. Our MS protocols allow for unequivocal determination of chemical structure, paramount to characterization of lipid A molecules that contain unique or novel chemical modifications. We also describe the radioisotopic labeling, and subsequent isolation, of lipid A from bacterial cells for analysis by TLC. Relative to MS-based protocols, TLC provides a more economical and rapid characterization method, but cannot be used to unambiguously assign lipid A chemical structures without the use of standards of known chemical structure. Over the last two decades isolation and characterization of lipid A has led to numerous exciting discoveries that have improved our understanding of the physiology of gram-negative bacteria, mechanisms of antibiotic resistance, the human innate immune response, and have provided many new targets in the development of antibacterial compounds.

Isolation and characterization of the lipid A domain of lipopolysaccharide (LPS) from gram-negative bacteria provides insight into cell surface based mechanisms of antibiotic resistance, bacterial survival and fitness, and how chemically diverse lipid A molecular species differentially modulate host innate immune responses.

Isolierung und chemische Charakterisierung von Lipid A von gramnegativen Bakterien

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS ...

Forschung

Chemie

Isolation and Preparation of Bacterial Cell Walls for Compositional Analysis by Ultra Performance Liquid Chromatography

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the face of turgor pressures several atmospheres in magnitude. Across the diverse shapes and sizes of the bacterial kingdom, the cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by short peptides. Peptidoglycan&#8217;s central importance to bacterial physiology underlies its use as an antibiotic target and has motivated genetic, structural, and cell biological studies of how it is robustly assembled during growth and division. Nonetheless, extensive investigations are still required to fully characterize the key enzymatic activities in peptidoglycan synthesis and the chemical composition of bacterial cell walls. High Performance Liquid Chromatography (HPLC) is a powerful analytical method for quantifying differences in the chemical composition of the walls of bacteria grown under a variety of environmental and genetic conditions, but its throughput is often limited. Here, we present a straightforward procedure for the isolation and preparation of bacterial cell walls for biological analyses of peptidoglycan via HPLC and Ultra Performance Liquid Chromatography (UPLC), an extension of HPLC that utilizes pumps to deliver ultra-high pressures of up to 15,000 psi, compared with 6,000 psi for HPLC. In combination with the preparation of bacterial cell walls presented here, the low-volume sample injectors, detectors with high sampling rates, smaller sample volumes, and shorter run times of UPLC will enable high resolution and throughput for novel discoveries of peptidoglycan composition and fundamental bacterial cell biology in most biological laboratories with access to an ultracentrifuge and UPLC.

The bacterial cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by peptides. Ultra Performance Liquid Chromatography provides high resolution and throughput for novel discoveries of peptidoglycan composition. We present a procedure for the isolation of cell walls (sacculi) and their subsequent preparation for analysis via UPLC.

Isolierung und Vorbereitung von bakteriellen Zellwänden für die Kompositionsanalyse durch Ultra Performance Liquid Chromatographie

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the ...

Extraction and Analysis of Microbial Phospholipid Fatty Acids in Soils

Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about the overall structure of terrestrial microbial communities. PLFA profiling has been extensively used in a range of ecosystems as a biological index of overall soil quality, and as a quantitative indicator of soil response to land management and other environmental stressors.
The standard method presented here outlines four key steps: 1. lipid extraction from soil samples with a single-phase chloroform mixture, 2. fractionation using solid phase extraction columns to isolate phospholipids from other extracted lipids, 3. methanolysis of phospholipids to produce fatty acid methyl esters (FAMEs), and 4. FAME analysis by capillary gas chromatography using a flame ionization detector (GC-FID). Two standards are used, including 1,2-dinonadecanoyl-sn-glycero-3-phosphocholine (PC(19:0/19:0)) to assess the overall recovery of the extraction method, and methyl decanoate (MeC10:0) as an internal standard (ISTD) for the GC analysis.

Phospholipid fatty acids provide information about the structure of soil microbial communities. We present methods for extraction from soil samples with a single-phase chloroform mixture, fractionation of extracted lipids using solid phase extraction columns, and methanolysis to produce fatty acid methyl esters, which are analyzed by capillary gas chromatography.

Extraktion und Analyse von Microbial Phospholipidfettsäuren in Böden

Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about ...

Umwelt

Au-Interaction of Slp1 Polymers and Monolayer from Lysinibacillus sphaericus JG-B53 - QCM-D, ICP-MS and AFM as Tools for Biomolecule-metal Studies

In this publication the gold sorption behavior of surface layer (S-layer) proteins (Slp1) of Lysinibacillus sphaericus JG-B53 is described. These biomolecules arrange in paracrystalline two-dimensional arrays on surfaces, bind metals, and are thus interesting for several biotechnical applications, such as biosorptive materials for the removal or recovery of different elements from the environment and industrial processes. The deposition of Au(0) nanoparticles on S-layers, either by S-layer directed synthesis 1 or adsorption of nanoparticles, opens new possibilities for diverse sensory applications. Although numerous studies have described the biosorptive properties of S-layers 2-5, a deeper understanding of protein-protein and protein-metal interaction still remains challenging. In the following study, inductively coupled mass spectrometry (ICP-MS) was used for the detection of metal sorption by suspended S-layers. This was correlated to measurements of quartz crystal microbalance with dissipation monitoring (QCM-D), which allows the online detection of proteinaceous monolayer formation and metal deposition, and thus, a more detailed understanding on metal binding.
The ICP-MS results indicated that the binding of Au(III) to the suspended S-layer polymers is pH dependent. The maximum binding of Au(III) was obtained at pH 4.0. The QCM-D investigations enabled the detection of Au(III) sorption as well as the deposition of Au(0)-NPs in real-time during the in situ experiments. Further, this method allowed studying the influence of metal binding on the protein lattice stability of Slp1. Structural properties and protein layer stability could be visualized directly after QCM-D experiment using atomic force microscopy (AFM). In conclusion, the combination of these different methods provides a deeper understanding of metal binding by bacterial S-layer proteins in suspension or as monolayers on either bacterial cells or recrystallized surfaces.

Au-Interaction of Slp1 Polymers and Monolayer from Lysinibacillus sphaericus JG-B53 - QCM-D, ICP-MS and AFM as Tools for Biomolecule-metal Studies

To obtain basic information on the sorption and recycling of gold from aqueous systems the interaction of Au(III) and Au(0) nanoparticles on S-layer proteins were investigated. The sorption of protein polymers was investigated by ICP-MS and that of proteinaceous monolayers by QCM-D. Subsequent AFM enables the imaging of the nanostructures.

Au-Wechselwirkung von SLP1 Polymere und Monolayer aus<em&gt; Lysinibacillus sphaericus</em&gt; JG-B53 - QCM-D, ICP-MS und AFM als Werkzeuge für Biomolekül-Metallforschung

In this publication the gold sorption behavior of surface layer (S-layer) proteins (Slp1) of Lysinibacillus sphaericus JG-B53 is described. These ...

Isolation of Lipoprotein Particles from Chicken Egg Yolk for the Study of Bacterial Pathogen Fatty Acid Incorporation into Membrane Phospholipids

Staphylococcus aureus and other Gram-positive pathogens incorporate fatty acids from the environment into membrane phospholipids. During infection, the majority of exogenous fatty acids are present within host lipoprotein particles. Uncertainty remains as to the reservoirs of host fatty acids and the mechanisms by which bacteria extract fatty acids from the lipoprotein particles. In this work, we describe protocols for enrichment of low-density lipoprotein (LDL) particles from chicken egg yolk and determining whether LDLs serve as fatty acid reservoirs for S. aureus. This method exploits unbiased lipidomic analysis and chicken LDLs, an effective and economical model for the exploration of interactions between LDLs and bacteria. The analysis of S. aureus integration of exogenous fatty acids from LDLs is performed using high-resolution/accurate mass spectrometry and tandem mass spectrometry, enabling the characterization of the fatty acid composition of the bacterial membrane and unbiased identification of novel combinations of fatty acids that arise in bacterial membrane lipids upon exposure to LDLs. These advanced mass spectrometry techniques offer an unparalleled perspective of fatty acid incorporation by revealing the specific exogenous fatty acids incorporated into the phospholipids. The methods outlined here are adaptable to the study of other bacterial pathogens and alternative sources of complex fatty acids.

This method provides a framework for studying incorporation of exogenous fatty acids from complex host sources into bacterial membranes, particularly Staphylococcus aureus. To achieve this, protocols for the enrichment of lipoprotein particles from chicken egg yolk and subsequent fatty acid profiling of bacterial phospholipids utilizing mass spectrometry are described.

Isolierung von Lipoproteinpartikeln aus Hühnereigelb zur Untersuchung des bakteriellen Pathogens Fettsäure-Inkorporation in Membranphospholipide

Staphylococcus aureus and other Gram-positive pathogens incorporate fatty acids from the environment into membrane phospholipids. During infection, the ...

Biochemie

Semi-Quantitative Analysis of Peptidoglycan by Liquid Chromatography Mass Spectrometry and Bioinformatics

Peptidoglycan is an important component of bacterial cell walls and a common cellular target for antimicrobials. Although aspects of peptidoglycan structure are fairly conserved across all bacteria, there is also considerable variation between Gram-positives/negatives and between species. In addition, there are numerous known variations, modifications, or adaptations to the peptidoglycan that can occur within a bacterial species in response to growth phase and/or environmental stimuli. These variations produce a highly dynamic structure that is known to participate in many cellular functions, including growth/division, antibiotic resistance, and host defense avoidance. To understand the variation within peptidoglycan, the overall structure must be broken down into its constitutive parts (known as muropeptides) and assessed for overall cellular composition. Peptidoglycomics uses advanced mass spectrometry combined with high-powered bioinformatic data analysis to examine peptidoglycan composition in fine detail. The following protocol describes the purification of peptidoglycan from bacterial cultures, the acquisition of muropeptide intensity data through a liquid chromatograph&#8212;mass spectrometer, and the differential analysis of peptidoglycan composition using bioinformatics.

This protocol covers a detailed analysis of peptidoglycan composition using liquid chromatography mass spectrometry coupled with advanced feature extraction and bioinformatic analysis software.

Semi-quantitative Analyse von Peptidoglycan mittels Flüssigkeitschromatographie, Massenspektrometrie und Bioinformatik

Peptidoglycan is an important component of bacterial cell walls and a common cellular target for antimicrobials. Although aspects of peptidoglycan ...

Ganglioside Extraction, Purification and Profiling

Gangliosides are glycosphingolipids that contain one or more sialic acid residues. They are found on all vertebrate cells and tissues but are especially abundant in the brain. Expressed primarily on the outer leaflet of the plasma membranes of cells, they modulate the activities of cell surface proteins via lateral association, act as receptors in cell-cell interactions and are targets for pathogens and toxins. Genetic dysregulation of ganglioside biosynthesis in humans results in severe congenital nervous system disorders. Because of their amphipathic nature, extraction, purification, and analysis of gangliosides require techniques that have been optimized by many investigators in the 80 years since their discovery. Here, we describe bench-level methods for the extraction, purification, and preliminary qualitative and quantitative analyses of major gangliosides from tissues and cells that can be completed in a few hours. We also describe methods for larger scale isolation and purification of major ganglioside species from brain. Together, these methods provide analytical and preparative scale access to this class of bioactive molecules.

Gangliosides are sialic acid-bearing glycosphingolipids that are particularly abundant in the brain. Their amphipathic nature requires organic/aqueous extraction and purification techniques to ensure optimal recovery and accurate analyses. This article provides overviews of analytic and preparative scale ganglioside extraction, purification, and thin layer chromatography analysis.

Gangliosidextraktion, -reinigung und -profilierung

Gangliosides are glycosphingolipids that contain one or more sialic acid residues. They are found on all vertebrate cells and tissues but are especially ...

Enrichment of Bacterial Lipoproteins and Preparation of N-terminal Lipopeptides for Structural Determination by Mass Spectrometry

Lipoproteins are important constituents of the bacterial cell envelope and potent activators of the mammalian innate immune response. Despite their significance to both cell physiology and immunology, much remains to be discovered about novel lipoprotein forms, how they are synthesized, and the effect of the various forms on host immunity. To enable thorough studies on lipoproteins, this protocol describes a method for bacterial lipoprotein enrichment and preparation of N-terminal tryptic lipopeptides for structural determination by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Expanding on an established Triton X-114 phase partitioning method for lipoprotein extraction and enrichment from the bacterial cell membrane, the protocol includes additional steps to remove non-lipoprotein contaminants, increasing lipoprotein yield and purity. Since lipoproteins are commonly used in Toll-like receptor (TLR) assays, it is critical to first characterize the N-terminal structure by MALDI-TOF MS. Herein, a method is presented to isolate concentrated hydrophobic peptides enriched in N-terminal lipopeptides suitable for direct analysis by MALDI-TOF MS/MS. Lipoproteins that have been separated by Sodium Dodecyl Sulfate Poly-Acrylamide Gel Electrophoresis (SDS-PAGE) are transferred to a nitrocellulose membrane, digested in situ with trypsin, sequentially washed to remove polar tryptic peptides, and finally eluted with chloroform-methanol. When coupled with MS of the more polar trypsinized peptides from wash solutions, this method provides the ability to both identify the lipoprotein and characterize its N-terminus in a single experiment. Intentional sodium adduct formation can also be employed as a tool to promote more structurally informative fragmentation spectra. Ultimately, enrichment of lipoproteins and determination of their N-terminal structures will permit more extensive studies on this ubiquitous class of bacterial proteins.

The enrichment of bacterial lipoproteins using a non-ionic surfactant phase partitioning method is described for direct use in TLR assays or other applications. Further steps are detailed to prepare N-terminal tryptic lipopeptides for structural characterization by mass spectrometry.

Bereicherung der bakterielle Lipoproteine und Vorbereitung der N-terminalen Lipopeptide Strukturaufklärung durch Massenspektrometrie

Lipoproteins are important constituents of the bacterial cell envelope and potent activators of the mammalian innate immune response. Despite their ...

Immunologie und Infektion

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii

This method works by partitioning the envelope of Gram-negative bacteria into total, inner, and outer membrane (OM) fractions and concludes with assays to assess the purity of the bilayers. The OM has an increased overall density compared to the inner membrane, largely due to the presence of lipooligosaccharides (LOS) and lipopolysaccharides (LPS) within the outer leaflet. LOS and LPS molecules are amphipathic glycolipids that have a similar structure, which consists of a lipid-A disaccharolipid and core-oligosaccharide substituent. However, only LPS molecules are decorated with a third subunit known as the O-polysaccharide, or O-antigen. The type and amount of glycolipids present will impact an organism&#8217;s OM density. Therefore, we tested whether the membranes of bacteria with varied glycolipid content could be similarly isolated using our technique. For the LPS-producing organisms, Salmonella enterica serovar Typhimurium and Escherichia coli, the membranes were easily isolated and the LPS O-antigen moiety did not impact bilayer partitioning. Acinetobacter baumannii produces LOS molecules, which have a similar mass to O-antigen deficient LPS molecules; however, the membranes of these microbes could not initially be separated. We reasoned that the OM of A. baumannii was less dense than that of Enterobacteriaceae, so the sucrose gradient was adjusted and the membranes were isolated. The technique can therefore be adapted and modified for use with other organisms.

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii

Gram-negative bacteria produce two spatially segregated membranes. The outer membrane is partitioned from the inner membrane by a periplasm and a peptidoglycan layer. The ability to isolate the dual bilayers of these microbes has been critical for understanding their physiology and pathogenesis.

Trennung der Zellhülle für gramnegative Bakterien in innere und äußere Membranfraktionen mit technischen Anpassungen für Acinetobacter baumannii

This method works by partitioning the envelope of Gram-negative bacteria into total, inner, and outer membrane (OM) fractions and concludes with assays to ...

Analysis of the Lipid Composition of Mycobacteria by Thin Layer Chromatography

Mycobacteria species can differ from one another in the rate of growth, presence of pigmentation, the colony morphology displayed on solid media, as well as other phenotypic characteristics. However, they all have in common the most relevant character of mycobacteria: its unique and highly hydrophobic cell wall. Mycobacteria species contain a membrane-covalent linked complex that includes arabinogalactan, peptidoglycan, and long-chains of mycolic acids with types that differ between mycobacteria species. Additionally, mycobacteria can also produce lipids that are located, non-covalently linked, on their cell surfaces, such as phthiocerol dimycocerosates (PDIM), phenolic glycolipids (PGL), glycopeptidolipids (GPL), acyltrehaloses (AT), or phosphatidil-inositol mannosides (PIM), among others. Some of them are considered virulence factors in pathogenic mycobacteria, or critical antigenic lipids in host-mycobacteria interaction. For these reasons, there is a significant interest in the study of mycobacterial lipids due to their application in several fields, from understanding their role in the pathogenicity of mycobacteria infections, to a possible implication as immunomodulatory agents for the treatment of infectious diseases and other pathologies such as cancer. Here, a simple approach to extract and analyze the total lipid content and the mycolic acid composition of mycobacteria cells grown in a solid medium using mixtures of organic solvents is presented. Once the lipid extracts are obtained, thin-layer chromatography (TLC) is performed to monitor the extracted compounds. The example experiment is performed with four different mycobacteria: the environmental fast-growing Mycolicibacterium brumae and Mycolicibacterium fortuitum, the attenuated slow-growing Mycobacterium bovis bacillus Calmette-Gu&#233;rin (BCG), and the opportunistic pathogen fast-growing Mycobacterium abscessus, demonstrating that methods shown in the present protocol can be used to a wide range of mycobacteria.

A protocol is presented to extract the total lipid content of the cell wall of a wide range of mycobacteria. Moreover, extraction and analytical protocols of the different types of mycolic acids are shown. A thin-layer chromatographic protocol to monitor these mycobacterial compounds is also provided.

Analyse der Lipidzusammensetzung von Mykobakterien mittels Dünnschichtchromatographie

Mycobacteria species can differ from one another in the rate of growth, presence of pigmentation, the colony morphology displayed on solid media, as well ...