Questa ricerca è stata sostenuta da borse di sanità pubblica e di servizio degli Stati Uniti AI69233 AI073843 dell&#39;Istituto Nazionale di allergie e malattie infettive. EPS è un Fellow Burroughs Wellcome nella patogenesi delle malattie infettive. KPH è stato finanziato dal Cellulare e Molecolare Microbiologia Formazione concessione Programma 5 T32 A107611-10.

1. Purificazione di emoglobina da sangue fresco <ol><li> Acquisire fresco sangue umano integrato con un anticoagulante. Mantenere il sangue sul ghiaccio oppure a 4 ° C per tutta la purificazione. </li><li> Centrifugare il sangue per 20 min a 1500 x g. I globuli rossi (RBC) sarà al fondo della provetta. Aspirare accuratamente il supernatante e risospendere il pellet delicatamente in gelata soluzione 0,9% (w / v) NaCl. Ripetere la centrifugazione e lavare 3 volte. </li><li> Risospendere il pellet in 1 volume di ghiaccio freddo 10 mM Tris-HCl (pH 8,0). Ciò induce lisi dei globuli rossi a causa della pressione osmotica. Aggiungi toluene a ~ 20% del volume finale. </li><li> Incubare a 4 ° C durante la notte su un girarrosto. </li><li> Centrifugare il lisato a 20.000 xg per 1 ora. Raccogliere la frazione centrale emolisato lasciando intatto il toluene (galleggiante in alto) e pellet. Utilizzare un lungo collo pipetta per raccogliere la frazione centrale. </li><li> Attraversare 0,44 micron filtro siringa. Se la soluzione contiene particellemateria e non può essere passato attraverso il filtro, ripetere il punto 1.5. </li><li> Purificare l&#39;emoglobina (Hb) con una ad alte prestazioni cromatografia liquida (HPLC), colonna a scambio anionico (Varian, PL-SAX 1000 al 8 pm, 150 mm × 4,6 mm). La fase mobile A è 10 mM Tris-HCl (pH 8,0) e la fase mobile B è 10 mM Tris-HCl (pH 8,0) + 0,5 M NaCl. A 0% -100% di pendenza solvente B è gestito oltre 2 min a 2,0 ml / min di portata. L&#39;eluizione viene controllata sulla base di assorbimento (λ: 410 nm e 280 nm). Raccogliere solo la frazione caratterizzato da un colore rosso brillante e un picco di assorbimento di primo piano (Figura 1). </li><li> Dializza l&#39;eluizione contro tampone fosfato salino (PBS) per una notte e poi per qualche ora ancora. Sterilizzare passando attraverso un filtro 0,22 micron siringa. </li><li> Per misurare la concentrazione di Hb, preparare soluzioni standard di Hb di concentrazioni note in PBS. Determinare la concentrazione di Hb nel campione mescolando le soluzioni standard (vedere la tabella con reagenti noied) o la soluzione campione con il reagente di 2x Drabkin (preparato da polvere) con un rapporto 1:1. Per esempio, miscelare 100 ul di soluzione Hb con 100 pl di reagente 2x Drabkin in piastre da 96 pozzetti. Incubare per 15 min e l&#39;assorbanza misura a 540 nm. Tracciare una curva standard e determinare la concentrazione di emoglobina nel campione. Da cinque a quindici mg / ml rendimenti sono tipici. </li><li> Eseguire 15-20 ug dell&#39;emoglobina purificata su un 15% SDS-PAGE in duplicato. Macchia uno dei gel, trasferire le proteine ​​di un&#39;altra gel su una membrana di nitrocellulosa e immunoblot per l&#39;emoglobina (Figura 2). </li><li> Congelare e conservare aliquote da 1 ml di emoglobina in azoto liquido. </li></ol> 2. Preparazione di ferro riducono la crescita media <ol><li> Preparare Roswell Park Memorial Institute (RPMI) brodo sciogliendo la polvere RPMI in acqua, aggiungere bicarbonato di sodio come raccomandato dal produttore e 1% di acidi cassamino (CA) (w / v). Sterilizzare passando attraverso un filtro 0,2 micron e conservare frigoriferorato. </li><li> Preparare metallo depleto RPMI (NRPMI) aggiungendo 7% (w / v) Chelex 100 e miscelazione notte su una piastra di agitazione. Rimuovere Chelex 100 passando attraverso un filtro 0,2 micron e conservare in frigorifero. Integrare mezzi essenziali con metalli non ferrosi: 25 ZnCl 2 pM, 25 pM MnCl 2, 100 mM CaCl 2 e 1 mM MgCl 2 preparati in anticipo come soluzione sterile 1000 x. Utilizzare contenitori di plastica usa e getta per questo passo per evitare la contaminazione da ferro riutilizzabili forniture. </li></ol> 3. Staphylococcus aureus Crescita emoglobina utilizzando come fonte di ferro Sole <ol><li> Streak S. aureus per l&#39;isolamento in Tryptic Soy Agar (TSA) da uno stock congelato. Incubare a 37 ° C per 20-24 ore. </li><li> Risospendere etilendiammina-N, N&#39;-bis (2-hydroxyphenylacetic acid) (EDDHA) in etanolo anidro a 100 mM. EDDHA non va in soluzione, ma è sterilizzato da etanolo. </li><li> Aggiungi EDDHA per RPMI ad una concentrazione finale di 0,5 mM. ConsentireEDDHA per dissolvere per almeno 30 minuti prima di procedere alla fase successiva. Causa lotto a lotto variazione, concentrazione finale EDDHA può essere necessario abbassare a 0,25 mm per consentire la crescita batterica. </li><li> Seminare singole colonie di S. aureus in 5 ml di RPMI contenente EDDHA in 15 ml con tappo a vite tubi conici. Incubare a 37 ° C con agitazione a 180 giri al minuto (rpm) per 16-20 ore. </li><li> Centrifugare le culture di notte per 5 min a 7500 xg e risospendere il pellet in NRPMI contenente 0,5 mM EDDHA. Normalizza OD 600 a ~ 3. </li><li> Preparare NRPMI contenente 2,5 microgrammi per ml Hb e EDDHA 0,1-1,0 mM. A causa delle variazioni tra i lotti, la concentrazione necessaria per EDDHA chelare ferro libero in NRPMI possono variare. </li><li> Subculture 10 ml di sospensione batterica dal punto 3,5 in 1 ml NRPMI EDDHA + + Hb in un ml 15 con tappo a vite tubo conico. </li><li> Incubare le colture a 37 ° C per 48 ore con agitazione a 180 rpm o su un tamburo di laminazione. </li><li&gt; Ogni 6-12 hr prendere OD 600 letture rimuovendo 50 microlitri della cultura e mescolandolo con 150 microlitri di PBS in piastre da 96 pozzetti. </li></ol>

<ol>
	<li>Mazmanian, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Passage+of+heme-iron+across+the+envelope+of+Staphylococcus+aureus.">Passage of heme-iron across the envelope of Staphylococcus aureus.</a> Science. 299, 906-909 (2003).</li><li>Pishchany, G., Skaar, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+for+blood:+hemoglobin+as+a+nutrient+source+for+pathogens.">Taste for blood: hemoglobin as a nutrient source for pathogens.</a> PLOS Pathogens. 8, e1002535 (2012).</li><li>Haley, K. P., Skaar, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+battle+for+iron:+host+sequestration+and+Staphylococcus+aureus+acquisition.">A battle for iron: host sequestration and Staphylococcus aureus acquisition.</a> Microbes and infection. Institut Pasteur. 14, 217-227 (2012).</li><li>Krishna Kumar, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+basis+for+hemoglobin+capture+by+Staphylococcus+aureus+cell-surface+protein.">Structural basis for hemoglobin capture by Staphylococcus aureus cell-surface protein.</a> IsdH. The Journal of biological chemistry. 286, 38439-38447 (2011).</li><li>Grigg, J. C., Mao, C. X., Murphy, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iron-coordinating+tyrosine+is+a+key+determinant+of+NEAT+domain+heme+transfer.">Iron-coordinating tyrosine is a key determinant of NEAT domain heme transfer.</a> Journal of Molecular Biology. 413, 684-698 (2011).</li><li>Villareal, V. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+weak+protein-protein+complexes+transfer+heme+across+the+cell+wall+of+Staphylococcus+aureus.">Transient weak protein-protein complexes transfer heme across the cell wall of Staphylococcus aureus.</a> Journal of the American Chemical Society. 133, 14176-14179 (2011).</li><li>Muryoi, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Demonstration+of+the+iron-regulated+surface+determinant+(Isd)+heme+transfer+pathway+in+Staphylococcus+aureus.">Demonstration of the iron-regulated surface determinant (Isd) heme transfer pathway in Staphylococcus aureus.</a> J. Biol. Chem. 283, 28125-28136 (2008).</li><li>Reniere, M. L., Skaar, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Staphylococcus+aureus+haem+oxygenases+are+differentially+regulated+by+iron+and+haem.">Staphylococcus aureus haem oxygenases are differentially regulated by iron and haem.</a> Mol. Microbiol. 69, 1304-1315 (2008).</li><li>Liu, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+hemin+transfer+from+IsdA+to+IsdC+in+the+iron-regulated+surface+determinant+(Isd)+heme+acquisition+system+of+Staphylococcus+aureus.">Direct hemin transfer from IsdA to IsdC in the iron-regulated surface determinant (Isd) heme acquisition system of Staphylococcus aureus.</a> J. Biol. Chem. 283, 6668-6676 (2008).</li><li>Pishchany, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specificity+for+human+hemoglobin+enhances+Staphylococcus+aureus+infection.">Specificity for human hemoglobin enhances Staphylococcus aureus infection.</a> Cell Host Microbe. 8, 544-550 (2010).</li><li>Pishchany, G., Dickey, S. E., Skaar, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subcellular+localization+of+the+Staphylococcus+aureus+heme+iron+transport+components+IsdA+and+IsdB.">Subcellular localization of the Staphylococcus aureus heme iron transport components IsdA and IsdB.</a> Infect. Immun. 77, 2624-2634 (2009).</li><li>Torres, V. J., Pishchany, G., Humayun, M., Schneewind, O., Skaar, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Staphylococcus+aureus+IsdB+is+a+hemoglobin+receptor+required+for+heme+iron+utilization.">Staphylococcus aureus IsdB is a hemoglobin receptor required for heme iron utilization.</a> J. Bacteriol. 188, 8421-8429 (2006).</li><li>Kim, H. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IsdA+and+IsdB+antibodies+protect+mice+against+Staphylococcus+aureus+abscess+formation+and+lethal+challenge.">IsdA and IsdB antibodies protect mice against Staphylococcus aureus abscess formation and lethal challenge.</a> Vaccine. 28, 6382-6392 (2010).</li><li>Cheng, A. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+requirements+for+Staphylococcus+aureus+abscess+formation+and+persistence+in+host+tissues.">Genetic requirements for Staphylococcus aureus abscess formation and persistence in host tissues.</a> Faseb J. 23, 3393-3404 (2009).</li><li>Andreini, C., Bertini, I., Cavallaro, G., Holliday, G. L., Thornton, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+ions+in+biological+catalysis:+from+enzyme+databases+to+general+principles.">Metal ions in biological catalysis: from enzyme databases to general principles.</a> J. Biol. Inorg. Chem. 13, 1205-1218 (2008).</li><li>Weinberg, E. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iron+availability+and+infection.">Iron availability and infection.</a> Biochimica et Biophysica Acta (BBA) - General Subjects. 1790, 600-605 (2009).</li><li>Drabkin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolism+of+the+Hemin+Chromoproteins.">Metabolism of the Hemin Chromoproteins.</a> Physiological Reviews. 31, 345-431 (1951).</li><li>Graversen, J. H., Madsen, M., Moestrup, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD163:+a+signal+receptor+scavenging+haptoglobin-hemoglobin+complexes+from+plasma.">CD163: a signal receptor scavenging haptoglobin-hemoglobin complexes from plasma.</a> The international journal of biochemistry &amp; cell biology. 34, 309-314 (2002).</li><li>Torres, V. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Staphylococcus+aureus+Fur+regulates+the+expression+of+virulence+factors+that+contribute+to+the+pathogenesis+of+pneumonia.">Staphylococcus aureus Fur regulates the expression of virulence factors that contribute to the pathogenesis of pneumonia.</a> Infect. Immun. 78, 1618-1628 (2010).</li><li>Hammer, N. D., Skaar, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+Mechanisms+of+Staphylococcus+aureus+Iron+Acquisition.">Molecular Mechanisms of Staphylococcus aureus Iron Acquisition.</a> Annu. Rev. Microbiol. , (2011).</li><li>Hurd, A. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+iron-regulated+surface+proteins+IsdA,+IsdB,+and+IsdH+are+not+required+for+heme+iron+utilization+in+Staphylococcus+aureus.">The iron-regulated surface proteins IsdA, IsdB, and IsdH are not required for heme iron utilization in Staphylococcus aureus.</a> Fems. Microbiology Letters. 329, 93-100 (2012).</li><li>Boys, B. L., Kuprowski, M. C., Konermann, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Symmetric+behavior+of+hemoglobin+alpha-+and+beta-+subunits+during+acid-induced+denaturation+observed+by+electrospray+mass+spectrometry.">Symmetric behavior of hemoglobin alpha- and beta- subunits during acid-induced denaturation observed by electrospray mass spectrometry.</a> Biochemistry. 46, 10675-10684 (2007).</li><li>Williams, R. C., Tsay, K. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+convenient+chromatographic+method+for+the+preparation+of+human+hemoglobin.">A convenient chromatographic method for the preparation of human hemoglobin.</a> Analytical Biochemistry. 54, 137-145 (1973).</li><li>Shen, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+unmodified+human+adult+hemoglobin+in+Escherichia+coli.">Production of unmodified human adult hemoglobin in Escherichia coli.</a> Proc. Natl. Acad. Sci. U.S.A. 90, 8108-8112 (1993).</li><li>Manjula, B. N., Acharya, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+and+molecular+analysis+of+hemoglobin+by+high-performance+liquid+chromatography.">Purification and molecular analysis of hemoglobin by high-performance liquid chromatography.</a> Methods Mol. Med. 82, 31-47 (2003).</li><li>Neilands, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+envelope+proteins+related+to+iron.">Microbial envelope proteins related to iron.</a> Annual review of microbiology. 36, 285-309 (1982).</li><li>Chart, H., Buck, M., Stevenson, P., Griffiths, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iron+regulated+outer+membrane+proteins+of+Escherichia+coli:+variations+in+expression+due+to+the+chelator+used+to+restrict+the+availability+of+iron.">Iron regulated outer membrane proteins of Escherichia coli: variations in expression due to the chelator used to restrict the availability of iron.</a> Journal of General Microbiology. 132, 1373-1378 (1986).</li><li>Rogers, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iron-Binding+Catechols+and+Virulence+in+Escherichia+coli.">Iron-Binding Catechols and Virulence in Escherichia coli.</a> Infection and Immunity. 7, 445-456 (1973).</li></ol>

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Il ferro è un nutriente essenziale necessario da parte di organismi di tutti i regni della vita 15. Nei vertebrati, ferro viene sequestrato per evitare la tossicità causata da questo elemento. Questo sequestro nasconde anche ferro da microbi invasori in un processo noto come immunità nutrizionale 16. In risposta, gli agenti patogeni hanno sviluppato strategie che eludono l&#39;immunità nutrizionale. Un tale meccanismo si basa su emoglobina, che è la fonte più abbondante di ferro all&#39;inter...

<table border="1"><tbody><tr><td> Nome del reagente / materiale </td><td> Azienda </td><td> Numero di catalogo </td><td> Commenti </td></tr><tr><td> HPLC colonna di scambio anionico </td><td> Varian </td><td> PL1551-3802 </td><td></td></tr><tr><td> Reagente Drabkin di </td><td> Sigma </td><td> D5941-6VL </td><td></td></tr><tr><td> Emoglobina normale </td><td> Pointe scientifico </td><td> H7506-STD </td><td></td></tr><tr><td> RPMI </td><td> HyClone </td><td> SH30011.02 </td><td></td></tr><tr><td> Chelex 100 di sodio forma </td><td> Sigma </td><td> C7901 </td><td></td></tr><tr><td> EDDHA </td><td> LGC Standards GmbH </td><td> ANC 001 </td><td></td></tr><tr><td> Emoglobina un anticorpo </td><td> Santa Cruz Biotechnology, Inc </td><td> SC-21005 </td><td> &lt;/ Td&gt; </tr><tr><td> Tryptic Soy Agar </td><td> BD </td><td> 236920 </td><td></td></tr></tbody></table>

staphylococcus aureus growth using human hemoglobin as an iron source

S. aureus è un batterio patogeno che richiede ferro a svolgere funzioni vitali metaboliche e causare la malattia. Il serbatoio più abbondante di ferro all&#39;interno dell&#39;ospite umano è eme, che è il cofattore di emoglobina. Per acquisire ferro da emoglobina, S. aureus utilizza un complesso sistema noto come il ferro regolato determinante superficie (Isd) sistema 1. Componenti della Isd emoglobina legano primo sistema host, quindi estrarre e importare eme, e infine liberare ferro eme nel citoplasma batterico 2,3. Questo percorso è stato sezionato attraverso numerosi studi in vitro 4-9. Inoltre, il contributo del sistema Isd di infezione è stato ripetutamente dimostrato in modelli murini 8,10-14. Stabilire il contributo del sistema Isd all&#39;emoglobina derivato acquisizione di ferro e la crescita ha dimostrato di essere più impegnativo. Saggi di crescita che utilizzano l&#39;emoglobina come fonte unica di ferro sono complicate by dell&#39;instabilità dell&#39;emoglobina commercialmente disponibile, contaminando ferro libero nel terreno di crescita, e la tossicità associata con chelanti del ferro. Qui vi presentiamo un metodo che supera queste limitazioni. Emoglobina alta qualità è preparato da sangue fresco e conservate in azoto liquido. Emoglobina purificata è integrato in ferro riducono medio mimando il ferro-poveri ambiente incontrate dagli agenti patogeni all&#39;interno del ospite vertebrato. Di fame S. aureus di ferro libero e integrando con una forma minimamente manipolato dell&#39;emoglobina ci indurre la crescita in un modo che è interamente dipendente dalla capacità di legare l&#39;emoglobina, estrarre eme, eme passare attraverso la busta cellula batterica e degradare eme nel citoplasma. Questo test sarà utile per i ricercatori che cercano di chiarire i meccanismi di acquisizione ferro hemoglobin-/heme-derived in S. aureus ed eventualmente di altri batteri patogeni.

Abbiamo purificato emoglobina umana da emolisato con HPLC (Protocollo passo 1.7). Figura 1 mostra registrato assorbanza dell&#39;eluato a 280 e 410 nm lunghezza d&#39;onda. Frazione 5 è stato raccolto e altre frazioni sono state scartate. I rendimenti di 5-15 milligrammi di emoglobina per millilitro di eluato sono in genere acquisiti. Emoglobina purificato è stato analizzato mediante SDS-PAGE in duplicato ed i gel sono stati colorati o per proteine ​​o trasferiti su nitrocellulosa e incubate (Prot...

Watch this Scientific Journal Video about Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source at JoVE.com

Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source

Qui si descrive un saggio di crescita per<em&gt; Staphylococcus aureus</em&gt; Utilizzando l&#39;emoglobina come unica fonte di nutrienti disponibili ferro. Questo saggio stabilisce il ruolo dei fattori batterici coinvolti nella emoglobina derivata acquisizione ferro.

Staphylococcus aureus crescita con emoglobina umana come fonte di ferro

S. aureus is a pathogenic bacterium that requires iron to  carry out vital metabolic functions and cause disease. The most abundant  reservoir of iron ...

staphylococcus-aureus-growth-using-human-hemoglobin-as-an-iron-source

Research

JoVE Journal

Immunology and Infection

Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source

16.4K Views.  Vanderbilt University Medical School. Qui si descrive un saggio di crescita per Staphylococcus aureus Utilizzando l'emoglobina come unica fonte di nutrienti disponibili ferro. Questo saggio stabilisce il ruolo dei fattori batterici coinvolti nella emoglobina derivata acquisizione ferro.

Video: Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source

The Use of Drip Flow and Rotating Disk Reactors for Staphylococcus aureus Biofilm Analysis

Most microbes in nature are thought to exist as surface-associated communities in biofilms.1 Bacterial biofilms are encased within a matrix and attached to a surface.2 Biofilm formation and development are commonly studied in the laboratory using batch systems such as microtiter plates or flow systems, such as flow-cells. These methodologies are useful for screening mutant and chemical libraries (microtiter plates)3 or growing biofilms for visualization (flow cells)4. Here we present detailed protocols for growing Staphylococcus aureus in two additional types of flow system biofilms: the drip flow biofilm reactor and the rotating disk biofilm reactor.
Drip flow biofilm reactors are designed for the study of biofilms grown under low shear conditions.5 The drip flow reactor consists of four parallel test channels, each capable of holding one standard glass microscope slide sized coupon, or a length of catheter or stint. The drip flow reactor is ideal for microsensor monitoring, general biofilm studies, biofilm cryosectioning samples, high biomass production, medical material evaluations, and indwelling medical device testing.6,7,8,9
The rotating disk reactor consists of a teflon disk containing recesses for removable coupons.10 The removable coupons can by made from any machinable material. The bottom of the rotating disk contains a bar magnet to allow disk rotation to create liquid surface shear across surface-flush coupons. The entire disk containing 18 coupons is placed in a 1000 mL glass side-arm reactor vessel. A liquid growth media is circulated through the vessel while the disk is rotated by a magnetic stirrer. The coupons are removed from the reactor vessel and then scraped to collect the biofilm sample for further study or microscopy imaging. Rotating disc reactors are designed for laboratory evaluations of biocide efficacy, biofilm removal, and performance of anti-fouling materials.9,11,12,13

The Use of Drip Flow and Rotating Disk Reactors for Staphylococcus aureus Biofilm Analysis

Protocols for utilizing open system flow biofilms with drip flow reactors and rotating disk reactors are presented in detail.

L&#39;uso del flusso gocciolamento e Reattori disco rotante per Staphylococcus aureus Analisi Biofilm

Most microbes in nature are thought to exist as surface-associated communities in biofilms.1  Bacterial biofilms are encased within a matrix and attached ...

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Immunologia e infezioni

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)

MRSA is a worldwide threat to public health, and MRSA skin and soft-tissue infections now account for more than half of all soft-tissue infections in the United States. Among soft-tissue infections, myositis, pyomyositis, and necrotizing fasciitis have been increasingly reported in association with MRSA arising from the community. To understand the interplay between MRSA and host immunity leading to more severe infection, the availability of animal models is critical, permitting the study of host and bacterial factors. Several infection models have been introduced to assess the pathogenesis of S. aureus during superficial skin infection. Here, we describe a subcutaneous infection model that examines the skin, subcutaneous, and muscle pathologies.

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA

Murine skin and soft tissue infection model is utilized for assessing the virulence function of methicillin resistant Staphylococcus aureus (MRSA) and the host immunological responses. Here, we presented a subcutaneous infection model for skin and soft tissue infection.

Sottocutaneo infezione di Staphylococcus aureus meticillino resistente (MRSA)

MRSA is a worldwide threat to public health, and MRSA skin and soft-tissue infections now account for more than half of all soft-tissue infections in the ...

Cost-effective Method for Microbial Source Tracking Using Specific Human and Animal Viruses

Microbial contamination of the environment represents a significant health risk. Classical bacterial fecal indicators have shown to have significant limitations, viruses are more resistant to many inactivation processes and standard fecal indicators do not inform on the source of contamination. The development of cost-effective methods for the concentration of viruses from water and molecular assays facilitates the applicability of viruses as indicators of fecal contamination and as microbial source tracking (MST) tools. Adenoviruses and polyomaviruses are DNA viruses infecting specific vertebrate species including humans and are persistently excreted in feces and/or urine in all geographical areas studied. In previous studies, we suggested the quantification of human adenoviruses (HAdV) and JC polyomaviruses (JCPyV) by quantitative PCR (qPCR) as an index of human fecal contamination. Recently, we have developed qPCR assays for the specific quantification of porcine adenoviruses (PAdV) and bovine polyomaviruses (BPyV) as animal fecal markers of contamination with sensitivities of 1-10 genome copies per test tube. In this study, we present the procedure to be followed to identify the source of contamination in water samples using these tools. As example of representative results, analysis of viruses in ground water presenting high levels of nitrates is shown.
Detection of viruses in low or moderately polluted waters requires the concentration of the viruses from at least several liters of water into a much smaller volume, a procedure that usually includes two concentration steps in series. This somewhat cumbersome procedure and the variability observed in viral recoveries significantly hamper the simultaneous processing of a large number of water samples.
In order to eliminate the bottleneck caused by the two-step procedures we have applied a one-step protocol developed in previous studies and applicable to a diversity of water matrices. The procedure includes: acidification of ten-liter water samples, flocculation by skimmed milk, gravity sedimentation of the flocculated materials, collection of the precipitate and centrifugation, resuspension of the precipitate in 10 ml phosphate buffer. The viral concentrate is used for the extraction of viral nucleic acids and the specific adenoviruses and polyomaviruses of interest are quantified by qPCR. High number of samples may be simultaneously analyzed using this low-cost concentration method.
The procedure has been applied to the analysis of bathing waters, seawater and river water and in this study, we present results analyzing groundwater samples. This high-throughput quantitative method is reliable, straightforward, and cost-effective.

The study describes a cost-effective method for the identification of the source of fecal/urine contamination or contamination by nitrates in water using qPCR for the specific quantification of human/porcine/bovine DNA viruses, adenoviruses and polyomaviruses, proposed as MST tools.

Costo-efficace metodo per il rilevamento di origine microbica Utilizzando specifici virus umani e animali

Microbial contamination of the environment represents a significant health risk. Classical bacterial fecal indicators have shown to have significant ...

Experimental Endocarditis Model of Methicillin Resistant Staphylococcus aureus (MRSA) in Rat

Endovascular infections, including endocarditis, are life-threatening infectious syndromes1-3. Staphylococcus aureus is the most common world-wide cause of such syndromes with unacceptably high morbidity and mortality even with appropriate antimicrobial agent treatments4-6. The increase in infections due to methicillin-resistant S. aureus (MRSA), the high rates of vancomycin clinical treatment failures and growing problems of linezolid and daptomycin resistance have all further complicated the management of patients with such infections, and led to high healthcare costs7, 8. In addition, it should be emphasized that most recent studies with antibiotic treatment outcomes have been based in clinical settings, and thus might well be influenced by host factors varying from patient-to-patient. Therefore, a relevant animal model of endovascular infection in which host factors are similar from animal-to-animal is more crucial to investigate microbial pathogenesis, as well as the efficacy of novel antimicrobial agents. Endocarditis in rat is a well-established experimental animal model that closely approximates human native valve endocarditis. This model has been used to examine the role of particular staphylococcal virulence factors and the efficacy of antibiotic treatment regimens for staphylococcal endocarditis. In this report, we describe the experimental endocarditis model due to MRSA that could be used to investigate bacterial pathogenesis and response to antibiotic treatment.

Experimental Endocarditis Model of Methicillin Resistant Staphylococcus aureus MRSA in Rat

Experimental rat endocarditis model due to methicillin-resistant S. aureus.

Endocardite modello sperimentale di meticillino resistente<em&gt; Staphylococcus aureus</em&gt; (MRSA) in Rat

Endovascular infections, including endocarditis, are life-threatening infectious syndromes1-3. Staphylococcus aureus is the most common world-wide cause ...

Studying Interactions of Staphylococcus aureus with Neutrophils by Flow Cytometry and Time Lapse Microscopy

We present methods to study the effect of phenol soluble modulins (PSMs) and other toxins produced and secreted by Staphylococcus aureus on neutrophils. To study the effects of the PSMs on neutrophils we isolate fresh neutrophils using density gradient centrifugation. These neutrophils are loaded with a dye that fluoresces upon calcium mobilization. The activation of neutrophils by PSMs initiates a rapid and transient increase in the free intracellular calcium concentration. In a flow cytometry experiment this rapid mobilization can be measured by monitoring the fluorescence of a pre-loaded dye that reacts to the increased concentration of free Ca2+. Using this method we can determine the PSM concentration necessary to activate the neutrophil, and measure the effects of specific and general inhibitors of the neutrophil activation.	
	To investigate the expression of the PSMs in the intracellular space, we have constructed reporter fusions of the promoter of the PSM&alpha; operon to GFP. When these reporter strains of S. aureus are phagocytosed by neutrophils, the induction of expression can be observed using fluorescence microscopy.

Studying Interactions of Staphylococcus aureus with Neutrophils by Flow Cytometry and Time Lapse Microscopy

We present methods to study the effect of PSMs and other toxins secreted by Staphylococcus aureus on neutrophils using flow cytometry and fluorescence microscopy.

Lo studio delle interazioni di<em&gt; Staphylococcus aureus</em&gt; Con neutrofili mediante citometria a flusso e Time Lapse Microscopy

We present methods to study the effect of phenol soluble modulins (PSMs)  and other toxins produced and secreted by Staphylococcus  aureus on neutrophils. ...

Targeting Biofilm Associated Staphylococcus aureus Using Resazurin Based Drug-susceptibility Assay

Most pathogenic bacteria are able to form biofilms during infection, but due to the difficulty of manipulating and assessing biofilms, the vast majority of laboratory work is conducted with planktonic cells. Here, we describe a peg plate biofilm assay as performed with Staphylococcus aureus. Bacterial biofilms are grown on pegs attached to a 96-well microtiter plate lid, washed through gentle submersion in buffer, and placed in a drug challenge plate. After subsequent incubation they are again washed and moved to a final recovery plate, in which the fluorescent dye resazurin serves as a viability indicator. This assay offers greatly increased ease-of-use, reliability, and reproducibility, as well as a wealth of data when conducted as a kinetic read. Moreover, this assay can be adapted to a medium-throughput drug screening approach by which an endpoint fluorescent readout is taken instead, offering a path for drug discovery efforts.

Targeting Biofilm Associated Staphylococcus aureus Using Resazurin Based Drug-susceptibility Assay

Most bacterial infections produce a biofilm. By virtue of their environment, biofilm associated bacteria are often phenotypically drug resistant. Novel antibacterial molecules that kill bacteria in biofilms are thus a high priority. We establish an assay to quickly screen for antimicrobial compounds that are effective at eradicating biofilms.

Targeting biofilm Associated<em&gt; Staphylococcus aureus</em&gt; Uso resazurina base Assay farmaco-sensibilità

Most pathogenic bacteria are able to form biofilms during infection, but due to the difficulty of manipulating and assessing biofilms, the vast majority ...

Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR (RS-PCR)

The ribosomal spacer PCR (RS-PCR) is a highly resolving and robust genotyping method for S. aureus that allows a high throughput at moderate costs and is, therefore, suitable to be used for routine purposes. For best resolution, data evaluation and data management, a miniaturized electrophoresis system is required. Together with such an electrophoresis system and the in-house developed software (freely available here) assignment of the pattern of bands to a genotype is standardized and straight forward. DNA extraction is simple (boiling prep), setting-up of the reactions is easy and they can be run on any standard PCR machine. PCR cycling is common except prolonged ramping and elongation times. Compared to spa typing and Multi Locus Sequence Typing (MLST), RS-PCR does not require DNA sequencing what simplifies the analysis considerably and allows a high throughput. Furthermore, the resolution for bovine strains of S. aureus is at least as good as spa typing and better than MLST or pulsed-field gel electrophoresis (PFGE). The RS-PCR data base includes presently a total of 141 genotypes and variants. The method is highly associated with the virulence gene pattern, contagiosity and pathogenicity of S. aureus strains involved in bovine mastitis. S. aureus genotype B (GTB) is contagious and causes herds problems causing large costs in the Switzerland and other European countries. All the other genotypes observed in Switzerland infect individual cows and quarters. Genotyping by RS-PCR allows the reliable prediction of the epidemiological and the pathogenic potential of S. aureus involved in bovine intramammary infection (IMI), two key factors for clinical veterinary medicine. Because of these beneficial properties together with moderate costs and a high sample throughput the goal of this publication is to give a detailed, step-by-step protocol for easily establishing and running RS-PCR for genotyping S. aureus in other laboratories.

Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR

Here, ribosomal spacer PCR (RS-PCR) is used together with a miniaturized electrophoresis system as a fast and high resolution method for genotyping S. aureus at moderate costs allowing a high throughput.

La genotipizzazione di<em&gt; Staphylococcus aureus</em&gt; Per ribosomiale Spacer PCR (RS-PCR)

The ribosomal spacer PCR (RS-PCR) is a highly resolving and robust genotyping method for S. aureus that allows a high throughput at moderate costs and is, ...

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus

One important feature of the major opportunistic human pathogen Staphylococcus aureus is its extraordinary ability to rapidly acquire resistance to antibiotics. Genomic studies reveal that S. aureus carries many virulence and resistance genes located in mobile genetic elements, suggesting that horizontal gene transfer (HGT) plays a critical role in S. aureus evolution. However, a full and detailed description of the methodology used to study HGT in S. aureus is still lacking, especially regarding natural transformation, which has been recently reported in this bacterium. This work describes three protocols that are useful for the in vitro investigation of HGT in S. aureus: conjugation, phage transduction, and natural transformation. To this aim, the cfr gene (chloramphenicol/florfenicol resistance), which confers the Phenicols, Lincosamides, Oxazolidinones, Pleuromutilins, and Streptogramin A (PhLOPSA)-resistance phenotype, was used. Understanding the mechanisms through which S. aureus transfers genetic materials to other strains is essential to comprehending the rapid acquisition of resistance and helps to clarify the modes of dissemination reported in surveillance programs or to further predict the spreading mode in the future.

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus

We describe here three different protocols for the in vitro investigation of conjugation, transduction, and natural transformation in Staphylococcus aureus.

Metodologia per lo studio del orizzontale Gene Transfer in<em&gt; Staphylococcus aureus</em

One important feature of the major opportunistic human pathogen Staphylococcus aureus is its extraordinary ability to rapidly acquire resistance to ...

A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection

Staphylococcus aureus (S. aureus)&#160;infections, including methicillin resistant stains, are an enormous burden on the healthcare system. With incidence rates of S. aureus infection climbing annually, there is a demand for additional research in its&#160;pathogenicity. Animal models of infectious disease advance our understanding of the host-pathogen response and lead to the development of effective therapeutics. Neutrophils play a primary role in the innate immune response that controls S. aureus infections by forming an abscess to wall off the infection and facilitate bacterial clearance; the number of neutrophils that infiltrate an S. aureus skin infection often correlates with disease outcome. LysM-EGFP mice, which possess the enhanced green fluorescent protein (EGFP) inserted in the Lysozyme M (LysM) promoter region (expressed primarily by neutrophils), when used in conjunction with in vivo whole animal fluorescence imaging (FLI) provide&#160;a means of quantifying neutrophil emigration noninvasively and longitudinally into wounded skin. When combined with a bioluminescent S. aureus strain and sequential in vivo whole animal bioluminescent imaging (BLI), it is possible to longitudinally monitor both the neutrophil recruitment dynamics and in vivo bacterial burden at the site of infection in anesthetized mice from onset of infection to resolution or death. Mice are more resistant to a number of virulence factors produced by S. aureus that facilitate effective colonization and infection in humans. Immunodeficient mice provide a more sensitive animal model to examine persistent S. aureus infections and the ability of therapeutics to boost innate immune responses. Herein, we characterize responses in LysM-EGFP mice that have been bred to MyD88-deficient mice (LysM-EGFP&#215;MyD88-/- mice) along with wild-type LysM-EGFP mice to investigate S. aureus skin wound infection. Multispectral simultaneous detection enabled study of neutrophil recruitment dynamics by using in vivo FLI, bacterial burden by using in vivo BLI, and wound healing longitudinally and noninvasively over time.

A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection

An approach is described for real-time detection of the innate immune response to cutaneous wounding and Staphylococcus aureus infection of mice. By comparing LysM-EGFP mice (which possess fluorescent neutrophils) with a LysM-EGFP crossbred immunodeficient mouse strain, we advance our understanding of infection and the development of approaches to combat infection.

Un modello di topo per valutare risposta immunitaria innata per infezione da Staphylococcus aureus

Staphylococcus aureus (S. aureus)&#160;infections, including methicillin resistant stains, are an enormous burden on the healthcare system. With incidence ...

Quantifying the Cytotoxicity of Staphylococcus aureus Against Human Polymorphonuclear Leukocytes

Staphylococcus aureus is capable of secreting a wide range of leukocidins that target and disrupt the membrane integrity of polymorphonuclear leukocytes (PMNs or neutrophils). This protocol describes both the purification of human PMNs and the quantification of S. aureus cytotoxicity against PMNs in three different sections. Section 1 details the isolation of PMNs and serum from human blood using density centrifugation. Section 2 tests the cytotoxicity of extracellular proteins produced by S. aureus against these purified human PMNs. Section 3 measures the cytotoxicity against human PMNs following the phagocytosis of live S. aureus. These procedures measure disruption of PMN plasma membrane integrity by S. aureus leukocidins using flow cytometry analysis of PMNs treated with propidium iodide, a DNA binding fluorophore that is cell membrane impermeable. Collectively, these methods have the advantage of rapidly testing S. aureus cytotoxicity against primary human PMNs and can be easily adapted to study other aspects of host-pathogen interactions.

Quantifying the Cytotoxicity of Staphylococcus aureus Against Human Polymorphonuclear Leukocytes

This protocol describes a method for the purification of polymorphonuclear leukocytes from whole human blood and two distinct assays that quantify the cytotoxicity of Staphylococcus aureus against these important innate immune cells.

Quantificare la Citotossicità dello Staphyloccus aureus contro il Polimorfo Umano Leukociti

Staphylococcus aureus is capable of secreting a wide range of leukocidins that target and disrupt the membrane integrity of polymorphonuclear leukocytes ...