Diese Arbeit wurde von der Small Business Innovation Research-Programm des National Institutes of Health (NIAID, 1R43AI082698-01) und der USDA National Institute of Food and Agriculture (NIFA, 2009-33610-20028) unterstützt.

1. Y. pestis Platte Impfung <ol><li> Streak Y. pestis A1122 (BeiResources # NR15) Stammkulturen auf Luria-Bertani (LB)-Agar (Miller). Verwenden Sie sterile Technik und erfüllen alle Y. pestis Manipulationen in einer Klasse-II-Typ A Biosicherheitswerkbank. Y. pestis A1122 ist ein Biosafety Level (BSL) 2 ausgeschlossen wählen Agent Belastung. Es fehlt sowohl die 75 kb Paar Low-Calcium-Reaktion (LCR) Virulenzplasmid und pgm locus, dass für die Virulenz erforderlich sind. Wachsen Sie Y. pestis bei 28 ° C für 48 h in einer statischen temperaturgeregelten Luft Inkubator. Die Wachstumsrate von Y. pestis ist langsam mit einer Generationszeit von 1,25 h 9. </li></ol> 2. Y. pestis flüssigen Medien Impfung <ol><li> Übertragen einer einzigen Y. pestis Kolonie in eine sterile 17 x 100 mm Kultur Röhrchen mit 2 ml LB-Medium mit einer sterilen Impföse Metall. Wählen Sie eine Kolonie, die eine einheitliche Größe ist, ist bezeichnend für die anderen Kolonien, und sich deutlich von dem Rest der Kolonien auf der Platte getrennt. Vortex Tube kurz und wachsen bei 28 ° C für ca. 20 h in einem Schüttelinkubator (225 rpm). </li></ol> 3. Y. pestis Auswuchs, Reporter Phagen hinaus und Biolumineszenz-Erkennung <ol><li> Verdünnen Sie die Nacht Y. pestis Kultur 1:20 in frischem LB-Medium in einem 50 ml Falcon-Röhrchen (z. B. 500 ul der Zellen in 9,5 ml Medium) und wachsen bei 28 ° C unter Schütteln (225 rpm). Wachsen, bis eine optische Dichte bei 600 nm (A 600) von 0,2 erreicht ist (ca. 5 h). Aktiv wachsende Zellen sind zu bevorzugen für den Nachweis, da die Fähigkeit des Phagen zu transduzieren einem biolumineszierenden Reaktion auf die Lebensfähigkeit und die Fitness des Wirtes Bakterien korreliert ist. Dennoch hat das Detektionssystem konnte gezeigt werden, kompatibel mit Zellen in allen Phasen des Wachstumszyklus 7 geerntet. </li><li> Generieren Sie das Substrat, die für die Biolumineszenzreaktion durch Herstellung einer 2% n-Decanal Lösung. Mix 200 ul n-Decanal mit 9,8 ml LB-Brühe. Vortex kräftig 5 s. Prime der Mikroplatten-Luminometer Injektor mit 2 ml der 2%-n-Decanal Lösung. Pre-set das Luminometer auf 67 ul der Decanal Lösung für jede Mikrotiterplatten und dann autoinject sofort lesen Sie die Probe für 10 s. </li><li> Dispense 1 mL Aliquots von LB-Medium in 3 Kulturröhrchen. Add 20 uL des Reporters Phagen-Stammlösung (stock von 5 x 10 9 Plaque-bildenden Einheiten [PFU] / ml) in jedes Röhrchen, die Phagen-und Medien-alone-Proben dient als negative Kontrolle. In Abwesenheit von Y. pestis-Zellen, sollte die Zugabe des Reporters Phagen nicht entlocken eine Biolumineszenz Antwort. </li><li> Dispense 1 mL Aliquots der Y. pestis Kultur (aus Schritt 3.1) in 6 Kulturröhrchen. Add 20 uL des Reporters Phagenstock bis 3 der Kulturen (Testkulturen). Die restlichen 3 Kulturen dienen als &quot;Zellen allein&quot; Negativ-Kontrolle (Hintergrund autobioluminescence). Mix Kulturen durch Vortexen kurz, und die Ernte 200 ul von jeder Probe (für die Zeit 0 zu lesen) und verzichten in eine weiße 96-well Mikrotiterplatten. Inkubieren Sie die verbleibenden Kultur bei 28 ° C unter Schütteln (225 rpm). </li><li> Messen Sie die Zeit 0 Muster für Biolumineszenz (relative light units, RLU) mit dem Mikrotiterplatten-Luminometer. </li><li> Ernte 200 ul jeder Probe nach 10, 20, 30, 40, 50 und 60 min post-Reporter Phagen hinaus und messen Sie die Probe für die Biolumineszenz. Wenn Y. pestis Zellen vorhanden sind, wird der Reporter Phagen spezifisch an die Zellen binden, injizieren ihre DNA, und die Gastgeber der Transkription und Translation Maschinen zu transkribieren und übersetzen die luxAB Reportergene (Abbildung 1). </li><li> Die Stärke des Signals und der Signal-Response-Zeit ist proportional zu der Anzahl der Zellen zu präsentieren. Bei hohen Konzentrationen von Zellen (10 5 -10 8 CFU / ml), einen signifikanten Anstieg in RLU im Vergleich zu den Kontrollen sollten innerhalb von 20 min deutlich. Am unteren Zelle Konzentrationen (10 2 -10 4 KBE / ml), sollte eine deutliche Steigerung in RLU werden innerhalb von 40-60 min deutlich. </li><li> Alternativ zur Erkennung ohne die Notwendigkeit für Y. beschleunigen pestis Auswuchs, eine Kolonie von einer frisch gewachsenen Platte gemischt (durch Vortexen) direkt in ein 1,5 ml Eppendorf-Röhrchen mit 200 ul LB-Brühe, Beherbergung der Reporter Phagen werden. Dosieren Sie die Zelle / Phagen Mischung in eine Vertiefung einer Mikrotiterplatte. Inkubieren Sie die Mikrotiterplatte bei 28 ° C und lesen Sie die Probe für die Biolumineszenz nach 60 min (single Zeitpunkt nur). </li></ol> 4. Repräsentative Ergebnisse: Ein Vertreter Zeitverlauf Experiment Reporter Phagen-vermittelte Erkennung von Y. pestis ist in Abbildung 2 dargestellt. Die negativen Kontrollen von 1) Phagen allein (keine Zellen), oder 2)-Zellen allein (ohne Phagen) bieten Baseline-Wertes der Biolumineszenz von ca. 20 RLU während der 60 min inkl.ubation (Ausgangswerte sind Luminometer spezifisch). Im Gegensatz dazu ist eine Zunahme der Biolumineszenz für die Testproben (reporter Phagen und Zellen) bei 15 min nach dem Phagen Neben evident. Die Signalstärke sollte stetig über 60 min. Inkubationen für längere Zeit (über 80 min), wird in ein Signal, das von der Spitze Signal aufgrund vermittelte Lyse der Wirtszellen Phagen Rückgang führen wird. Ähnliche Ergebnisse werden bei einer Inkubationstemperatur von 37 ° C gewonnen wurde, obwohl die optimale Temperatur für Y. pestis Wachstum beträgt 28 ° C 9. <img src="/files/ftp_upload/2740/2740fig2.jpg" alt="Abbildung 2"/> Abbildung 2. Phage-vermittelte Biolumineszenz Detektion von Y. pestis. Zum Zeitpunkt 0, Reporter Phagen und Zellen wurden gemischt, bei 28 ° C, und Biolumineszenz (RLU) wurde im Laufe der Zeit überwacht. Ein signifikanter Anstieg in RLU (* Studenten t-Test, p &lt;0,05) liegt auf der Hand innerhalb von 15 min.

<ol>
	<li>Darling, R. G., Catlett, C. L., Huebner, K. D., Jarrett, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Threats+in+bioterrorism.+I:+CDC+category+A+agents.">Threats in bioterrorism. I: CDC category A agents.</a> Emerg Med Clin North Am. 20, 273-309 (2002).</li><li>Chu, M. 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> Laboratory manual of plague diagnostic tests.. , (2000).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> , (1999).</li><li>Inglesby, T. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anthrax+as+a+biological+weapon,+2002:+updated+recommendations+for+management.">Anthrax as a biological weapon, 2002: updated recommendations for management.</a> JAMA. 287, 2236-2252 (2002).</li><li>Schuch, R., Fischetti, V. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detailed+genomic+analysis+of+the+Wbeta+and+gamma+phages+infecting+Bacillus+anthracis:+implications+for+evolution+of+environmental+fitness+and+antibiotic+resistance.">Detailed genomic analysis of the Wbeta and gamma phages infecting Bacillus anthracis: implications for evolution of environmental fitness and antibiotic resistance.</a> J Bacteriol. 188, 3037-3051 (2006).</li><li>Garcia, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+genome+sequence+of+Yersinia+pestis+bacteriophage+phiA1122+reveals+an+intimate+history+with+the+coliphage+T3+and+T7+genomes.">The genome sequence of Yersinia pestis bacteriophage phiA1122 reveals an intimate history with the coliphage T3 and T7 genomes.</a> J Bacteriol. 185, 5248-5262 (2003).</li><li>Schofield, D. A., Molineux, I. J., Westwater, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnostic+bioluminescent+phage+for+detection+of+Yersinia+pestis.">Diagnostic bioluminescent phage for detection of Yersinia pestis.</a> Journal of Clinical Microbiology. 47, 3887-3894 (2009).</li><li>Schofield, D. A., Westwater, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phage-mediated+bioluminescent+detection+of+Bacillus+anthracis.">Phage-mediated bioluminescent detection of Bacillus anthracis.</a> Journal of Applied Microbiology. 107, 468-478 (2009).</li><li>Chu, M. 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> CDC: Basic laboratory protocols for the presumptive identification of Yersinia pestis. , 1-19 (2001).</li><li>Gunnison, J. B., Larson, A., Lazarus, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+differentiation+between+Pasteurella+pestis+and+Pasteurella+pseudotuberculosis+by+action+of+bacteriophage.">Rapid differentiation between Pasteurella pestis and Pasteurella pseudotuberculosis by action of bacteriophage.</a> J Infect Dis. 88, 254-255 (1951).</li><li>Lazarus, A. S., Gunnison, 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=The+Action+of+Pasteurella+pestis+Bacteriophage+on+Strains+of+Pasteurella,+Salmonella,+and+Shigella.">The Action of Pasteurella pestis Bacteriophage on Strains of Pasteurella, Salmonella, and Shigella.</a> J Bacteriol. 53, 705-714 (1947).</li><li>Sergueev, K. V., He, Y., Borschel, R. H., Nikolich, M. P., Filippov, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+and+sensitive+detection+of+Yersinia+pestis+using+amplification+of+plague+diagnostic+bacteriophages+monitored+by+real-time+PCR.">Rapid and sensitive detection of Yersinia pestis using amplification of plague diagnostic bacteriophages monitored by real-time PCR.</a> PLoS One. 5, e11337-e11337 (2010).</li></ol>

Diese Methode zeigt die Fähigkeit des Reporters Phagen schnell erkennen Y. pestis, da die Reporter Phagen können transduzieren eines Biolumineszenz-Signal Antwort auf kultivierten Y. pestis-Zellen innerhalb von 20 min nach dem Phagen hinaus. Der Reporter Phagen ist auch in der Lage direkt nachzuweisen Y. pestis in klinischen Matrizen, ohne die Voraussetzung der Isolation und der anschließende Kultivierung 7. Im Vergleich zu den Standard-Phagen-Lyse-Assays die in der Regel 48 h f?...

<table border="1"><tbody><tr><th> Name des Reagenzes </th><th> Firma </th><th> Katalog-Nummer </th></tr><tr><td> Difco LB-Agar, Miller </td><td> VWR </td><td> 90003-346 </td></tr><tr><td> Difco LB Brühe, Miller </td><td> VWR </td><td> 90003-350 </td></tr><tr><td> 17 x 100 mm Kulturröhrchen </td><td> USA Scientific </td><td> 1485-0810 </td></tr><tr><td> n-Decanal </td><td> Sigma </td><td> D7384 </td></tr><tr><td> Veritas Mikroplatten-Luminometer </td><td> Turner Biosystems </td><td> 9100-001 </td></tr><tr><td> Microlite Mikrotiterplatten 96-Well-Platte </td><td> VWR </td><td> 62402-984 </td></tr></tbody></table>

'bioluminescent' reporter phage for the detection of category a bacterial pathogens

Yersinia pestis und Bacillus anthracis sind Kategorie A bakterielle Erreger, die die Erreger der Pest und Milzbrand sind jeweils 1. Obwohl das natürliche Vorkommen beider Krankheiten &quot;ist jetzt relativ selten sind, ist die Möglichkeit terroristischer Gruppen mit diesen Erregern als Biowaffe Echtzeit. Wegen der Krankheit innewohnende Kommunikationsfähigkeit, schnelle klinischen Verlauf und eine hohe Sterblichkeitsrate, ist es entscheidend, dass ein Ausbruch schnell erkannt werden. Deshalb Methoden, die eine schnelle Erkennung und Diagnose stellen sind unerlässlich, um eine sofortige Umsetzung der Maßnahmen des Gesundheitswesens und die Aktivierung des Krisenmanagements gewährleisten. Rekombinante Phagen-Reporter kann einen schnellen und spezifischen Ansatz für den Nachweis von Y. pestis und B. anthracis. Die Centers for Disease Control and Prevention nutzen derzeit das klassische Phagen Lyse-Assays für die bestätigten Identifizierung dieser bakteriellen Erregern 2-4. Diese Assays profitieren von natürlich vorkommenden Phagen, die spezifisch und lytisch sind für ihre bakteriellen Wirten. Nach Wachstum über Nacht der kultivierten Bakterien in Gegenwart der spezifischen Phagen, bietet die Bildung von Plaques (bakterielle Lyse) eine positive Identifikation der bakteriellen Ziel. Obwohl diese Tests robust sind, leiden sie unter drei Mängel: 1) sie sind im Labor basiert, 2) die sie benötigen bakterielle Isolierung und Kultivierung von den verdächtigen Probe, und 3) nehmen sie 24-36 h in Anspruch nehmen. Um diese Probleme anzugehen, wurden rekombinante &quot;light-Tag&quot;-Reporter Phagen genetisch durch die Integration der Vibrio harveyi luxAB Gene in das Genom von Y. entwickelt pestis und B. anthracis spezifische Phagen 5-8. Die daraus resultierende luxAB Reporter Phagen konnten ihre spezifische Ziel von schnell zu erkennen (in Minuten) und sensibel Übertragung einer Biolumineszenz Phänotyp an den Empfänger-Zellen. Wichtig ist, war die Detektion entweder mit kultivierten Zellen oder Empfänger mit Mock-infizierte klinische Proben 7 erhalten. Zu Demonstrationszwecken hier beschreiben wir das Verfahren für die Phagen-vermittelte Erkennung eines bekannten Y. pestis isolieren mit einem luxAB Reporter Phagen von der CDC Pest diagnostische Phagen ΦA1122 6,7 (Abb. 1) konstruiert. Eine ähnliche Methode, mit geringfügigen Änderungen (zB Änderung des Wachstums Temperatur und Medien), kann für den Nachweis von B. verwendet werden anthracis-Isolate mit der B. anthracis Reporter Phagen Wβ: luxAB 8. Die Methode beschreibt die Phagen-vermittelte Transduktion eines biolumescent Phänotyp angebaut Y. pestis Zellen, die anschließend gemessen werden mit einem Mikrotiterplatten-Luminometer. Die wesentlichen Vorteile dieser Methode gegenüber der traditionellen Phagen Lyse-Assays ist die einfache Handhabung, die schnelle Ergebnisse, und die Möglichkeit, mehrere Proben gleichzeitig Test in einer 96-well Mikrotiterplatten-Format. <img src="/files/ftp_upload/2740/2740fig1.jpg" alt="Abbildung 1"/> Abbildung 1. Erkennung schematisch. Die Phagen werden mit der Probe vermischt, infiziert der Phage die Zelle, luxAB ausgedrückt sind, und die Zelle bioluminesces. Probenvorbereitung ist nicht notwendig, die Phagen und Zellen vermischt und anschließend für Licht gemessen.

Watch this Scientific Journal Video about 'Bioluminescent' Reporter Phage for the Detection of Category A Bacterial Pathogens at JoVE.com

&#039;Bioluminescent&#039; Reporter Phage for the Detection of Category A Bacterial Pathogens

Eine einfache Methode zur Identifizierung der prioritären bakteriellen Erregern ist gentechnisch Reporter Phagen verwenden. Diese Reporter-Phagen, die spezifisch für ihre besonderen Wirtsarten sind, sind in der Lage schnell Transduktion eines Biolumineszenz-Signal Antwort auf Wirtszellen. Hier beschreiben wir die Verwendung von Reporter Phagen für den Nachweis von<em&gt; Yersinia pestis</em&gt;.

&quot;Bioluminescent &#39;Reporter Phage für den Nachweis von Kategorie A bakteriellen Erregern

Yersinia pestis and Bacillus anthracis are Category A bacterial pathogens that are the causative agents of the plague and anthrax, respectively 1. ...

bioluminescent-reporter-phage-for-detection-category-bacterial

Research

JoVE Journal

Immunology and Infection

'Bioluminescent' Reporter Phage for the Detection of Category A Bacterial Pathogens

13.3K Aufrufe.  Guild Associates, Inc.. Eine einfache Methode zur Identifizierung der prioritären bakteriellen Erregern ist gentechnisch Reporter Phagen verwenden. Diese Reporter-Phagen, die spezifisch für ihre besonderen Wirtsarten sind, sind in der Lage schnell Transduktion eines Biolumineszenz-Signal Antwort auf Wirtszellen. Hier beschreiben wir die Verwendung von Reporter Phagen für den Nachweis von Yersinia pestis.

Serie: 'Bioluminescent' Reporter Phage for the Detection of Category A Bacterial Pathogens

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of infection with influenza virus alone. Instead, most individuals are thought to have succumbed to a secondary bacterial infection, predominately caused by the bacterium Streptococcus pneumoniae (the pneumococcus). The synergistic relationship between infections caused by influenza virus and the pneumococcus has subsequently been observed during the 1957 Asian influenza virus pandemic, as well as during seasonal outbreaks of the virus (reviewed in 1, 2). Here, we describe a protocol used to investigate the mechanism(s) that may be involved in increased morbidity as a result of concurrent influenza A virus and S. pneumoniae infection. We have developed an infant murine model to reliably and reproducibly demonstrate the effects of influenza virus infection of mice colonised with S. pneumoniae. Using this protocol, we have provided the first insight into the kinetics of pneumococcal transmission between co-housed, neonatal mice using in vivo imaging 3.

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

A concurrent infection with influenza A virus is one of the factors implicated in the induction of invasive pneumococcal disease during asymptomatic Streptococcus pneumoniae carriage. Here we describe a mixed infection method using infant mice to investigate the synergism between these two respiratory pathogens.

Mit Bioluminescent Imaging, um Synergie von Untersuchen Streptococcus pneumoniae Und Influenza A Virus in Infant Mäuse

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of ...

Forschung

Immunologie und Infektion

Introducing Shear Stress in the Study of Bacterial Adhesion

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the initial and determining step of the pathogenesis. Although experimentally adhesion is mostly studied in static conditions adhesion actually takes place in the presence of flowing liquid. First encounters between bacteria and their host often occur at the mucosal level, mouth, lung, gut, eye, etc. where mucus flows along the surface of epithelial cells. Later in infection, pathogens occasionally access the blood circulation causing life-threatening illnesses such as septicemia, sepsis and meningitis. A defining feature of these infections is the ability of these pathogens to interact with endothelial cells in presence of circulating blood. The presence of flowing liquid, mucus or blood for instance, determines adhesion because it generates a mechanical force on the pathogen. To characterize the effect of flowing liquid one usually refers to the notion of shear stress, which is the tangential force exerted per unit area by a fluid moving near a stationary wall, expressed in dynes/cm2. Intensities of shear stress vary widely according to the different vessels type, size, organ, location etc. (0-100 dynes/cm2). Circulation in capillaries can reach very low shear stress values and even temporarily stop during periods ranging between a few seconds to several minutes 1. On the other end of the spectrum shear stress in arterioles can reach 100 dynes/cm2 2. The impact of shear stress on different biological processes has been clearly demonstrated as for instance during the interaction of leukocytes with the endothelium 3. To take into account this mechanical parameter in the process of bacterial adhesion we took advantage of an experimental procedure based on the use of a disposable flow chamber 4. Host cells are grown in the flow chamber and fluorescent bacteria are introduced in the flow controlled by a syringe pump. We initially focused our investigations on the bacterial pathogen Neisseria meningitidis, a Gram-negative bacterium responsible for septicemia and meningitis. The procedure described here allowed us to study the impact of shear stress on the ability of the bacteria to: adhere to cells 1, to proliferate on the cell surface 5and to detach to colonize new sites 6 (Figure 1). Complementary technical information can be found in reference 7. Shear stress values presented here were chosen based on our previous experience1 and to represent values found in the literature. The protocol should be applicable to a wide range of pathogens with specific adjustments depending on the objectives of the study.

During the infection process, a key step is the adhesion of pathogens with host cells. In most instances this adhesion step occurs in the presence of mechanical stress generated by flowing liquid. We describe a technique that introduces shear stress as an important parameter in the study of bacterial adhesion.

Introducing Schubspannung in der Studie der bakteriellen Adhäsion

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the ...

Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens

Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen interactions 1. The major cell types of the innate immune system, macrophages and neutrophils, develop during the first days of embryogenesis prior to the maturation of lymphocytes that are required for adaptive immune responses. The ease of obtaining large numbers of embryos, their accessibility due to external development, the optical transparency of embryonic and larval stages, a wide range of genetic tools, extensive mutant resources and collections of transgenic reporter lines, all add to the versatility of the zebrafish model. Salmonella enterica serovar Typhimurium (S. typhimurium) and Mycobacterium marinum can reside intracellularly in macrophages and are frequently used to study host-pathogen interactions in zebrafish embryos. The infection processes of these two bacterial pathogens are interesting to compare because S. typhimurium infection is acute and lethal within one day, whereas M. marinum infection is chronic and can be imaged up to the larval stage 2, 3. The site of micro-injection of bacteria into the embryo (Figure 1) determines whether the infection will rapidly become systemic or will initially remain localized. A rapid systemic infection can be established by micro-injecting bacteria directly into the blood circulation via the caudal vein at the posterior blood island or via the Duct of Cuvier, a wide circulation channel on the yolk sac connecting the heart to the trunk vasculature. At 1 dpf, when embryos at this stage have phagocytically active macrophages but neutrophils have not yet matured, injecting into the blood island is preferred. For injections at 2-3 dpf, when embryos also have developed functional (myeloperoxidase-producing) neutrophils, the Duct of Cuvier is preferred as the injection site. To study directed migration of myeloid cells towards local infections, bacteria can be injected into the tail muscle, otic vesicle, or hindbrain ventricle 4-6. In addition, the notochord, a structure that appears to be normally inaccessible to myeloid cells, is highly susceptible to local infection 7. A useful alternative for high-throughput applications is the injection of bacteria into the yolk of embryos within the first hours after fertilization 8. Combining fluorescent bacteria and transgenic zebrafish lines with fluorescent macrophages or neutrophils creates ideal circumstances for multi-color imaging of host-pathogen interactions. This video article will describe detailed protocols for intravenous and local infection of zebrafish embryos with S. typhimurium or M. marinum bacteria and for subsequent fluorescence imaging of the interaction with cells of the innate immune system.

Transparent zebrafish embryos have proved useful model hosts to visualize and functionally study interactions between innate immune cells and intracellular bacterial pathogens, such as Salmonella typhimurium and Mycobacterium marinum. Micro-injection of bacteria and multi-color fluorescence imaging are essential techniques involved in the application of zebrafish embryo infection models.

Die Infektion von Zebrafisch-Embryos mit Intrazelluläre bakterielle Krankheitserreger

Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen ...

Bioluminescent Bacterial Imaging In Vivo

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of bacteria in gene and cell therapy for cancer. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumors following systemic administration. Bacteria engineered to express the lux gene cassette permit BLI detection of the bacteria and concurrently tumor sites. The location and levels of bacteria within tumors over time can be readily examined, visualized in two or three dimensions. The method is applicable to a wide range of bacterial species and tumor xenograft types. This article describes the protocol for analysis of bioluminescent bacteria within subcutaneous tumor bearing mice. Visualization of commensal bacteria in the Gastrointestinal tract (GIT) by BLI is also described. This powerful, and cheap, real-time imaging strategy represents an ideal method for the study of bacteria in vivo in the context of cancer research, in particular gene therapy, and infectious disease. This video outlines the procedure for studying lux-tagged E. coli in live mice, demonstrating the spatial and temporal readout achievable utilizing BLI with the IVIS system.

Bioluminescent Bacterial Imaging In Vivo

This article describes the administration of lux-tagged bacteria to mice and subsequent in vivo analysis using IVIS bioluminescence imaging.

Bioluminescent Bakterielle Imaging<em&gt; In Vivo</em

This video describes the use of whole body bioluminesce imaging (BLI) for the study of bacterial trafficking in live mice, with an emphasis on the use of ...

Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans

The basidiomycete Cryptococcus neoformans, an invasive opportunistic pathogen of the central nervous system, is the most frequent cause of fungal meningitis worldwide resulting in more than 625,000 deaths per year worldwide.&#160;Although electroporation has been developed for the transformation of plasmids in Cryptococcus, only&#160;biolistic&#160;delivery provides&#160;an effective means to transform&#160;linear&#160;DNA&#160;that can be integrated into the genome by homologous recombination.&#160;
Acetate has been shown to be a major fermentation product during cryptococcal infection, but the significance of this is not yet known.&#160;A bacterial pathway composed of the enzymes xylulose-5-phosphate/fructose-6-phosphate phosphoketolase (Xfp) and acetate kinase (Ack) is one of three potential pathways for acetate production in C. neoformans. Here, we demonstrate the biolistic transformation of a construct, which has the gene encoding Ack fused to the fluorescent tag mCherry, into&#160;C. neoformans. We then confirm integration of the ACK-mCherry fusion into the&#160;ACK&#160;locus.

Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans

Biolistic transformation is a method used to generate stable integration of DNA into the genome of the opportunistic pathogen Cryptococcus neoformans through homologous recombination. We will demonstrate biolistic transformation of a construct, which has the gene encoding acetate kinase fused to the fluorescent tag mCherry into&#160;C. neoformans.

Biolistischen Transformation einer Leuchtstoff Tagged-Gens in den Opportunistic Pilzpathogenentwicklung<em&gt; Cryptococcus neoformans</em

The basidiomycete Cryptococcus neoformans, an invasive opportunistic pathogen of the central nervous system, is the most frequent cause of fungal ...

High-throughput Detection of Respiratory Pathogens in Animal Specimens by Nanoscale PCR

Nanoliter scale real-time PCR uses spatial multiplexing to allow multiple assays to be run in parallel on a single plate without the typical drawbacks of combining reactions together. We designed and evaluated a panel based on this principle to rapidly identify the presence of common disease agents in dogs and horses with acute respiratory illness. This manuscript describes a nanoscale diagnostic PCR workflow for sample preparation, amplification, and analysis of target pathogen sequences, focusing on procedures that are different from microliter scale reactions. In the respiratory panel presented, 18 assays were each set up in triplicate, accommodating up to 48 samples per plate. A universal extraction and pre-amplification workflow was optimized for high-throughput sample preparation to accommodate multiple matrices and DNA and RNA based pathogens. Representative data are presented for one RNA target (influenza A matrix) and one DNA target (equine herpesvirus 1). The ability to quickly and accurately test for a comprehensive, syndrome-based group of pathogens is a valuable tool for improving efficiency and ergonomics of diagnostic testing and for acute respiratory disease diagnosis and management.

High-throughput testing of DNA and RNA based pathogens by nanoscale PCR is described using a syndromic canine and equine respiratory PCR panel.

Hochdurchsatz-Nachweis von Respiratory Pathogens in Tier Proben durch nanoskalige PCR

Nanoliter scale real-time PCR uses spatial multiplexing to allow multiple assays to be run in parallel on a single plate without the typical drawbacks of ...

Development of a Hepatitis B Virus Reporter System to Monitor the Early Stages of the Replication Cycle

Currently, it is possible to construct recombinant forms of various viruses, such as human immunodeficiency virus 1 (HIV-1) and hepatitis C virus (HCV), that carry foreign genes such as a reporter or marker protein in their genomes. These recombinant viruses usually faithfully mimic the life cycle of the original virus in infected cells and exhibit the same host range dependence. The development of a recombinant virus enables the efficient screening of inhibitors and the identification of specific host factors. However, to date the construction of recombinant hepatitis B virus (HBV) has been difficult because of various experimental limitations. The main limitation is the compact genome size of HBV, and a fairly strict genome size that does not exceed 1.3 genome sizes, that must be packaged into virions. Thus, the size of a foreign gene to be inserted should be smaller than 0.4 kb if no deletion of the genome DNA is to be performed. Therefore, to overcome this size limitation, the deletion of some HBV DNA is required. Here, we report the construction of recombinant HBV encoding a reporter gene to monitor the early stage of the HBV replication cycle by replacing part of the HBV core-coding region with the reporter gene by deleting part of the HBV pol coding region. Detection of recombinant HBV infection, monitored by the reporter activity, was highly sensitive and less expensive than detection using the currently available conventional methods to evaluate HBV infection. This system will be useful for a number of applications including high-throughput screening for the identification of anti-HBV inhibitors, host factors and virus-susceptible cells.

Here we describe a newly developed hepatitis B virus (HBV) reporter system to monitor the early stages of the HBV life cycle. This simplified in vitro system will aid in the screening of anti-HBV agents using a high-throughput strategy.

Entwicklung eines Systems Hepatitis-B-Virus Reporter den frühen Stadien des Replikationszyklus zu überwachen

Currently, it is possible to construct recombinant forms of various viruses, such as human immunodeficiency virus 1 (HIV-1) and hepatitis C virus (HCV), ...

A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella spp./Shigella spp. The gold standard method for the detection of Salmonella spp./Shigella spp. is direct culture but this is labor-intensive and time-consuming. Here, we describe a high-throughput platform for Salmonella spp./Shigella spp. screening, using real-time polymerase chain reaction (PCR) combined with guided culture. There are two major stages: real-time PCR and the guided culture. For the first stage (real-time PCR), we explain each step of the method: sample collection, pre-enrichment, DNA extraction and real-time PCR. If the real-time PCR result is positive, then the second stage (guided culture) is performed: selective culture, biochemical identification and serological characterization. We also illustrate representative results generated from it. The protocol described here would be a valuable platform for the rapid, specific, sensitive and high-throughput screening of Salmonella spp./Shigella spp.

A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.

Salmonella spp./Shigella spp. are common pathogens attributed to diarrhea. Here, we describe a high-throughput platform for the screening of Salmonella spp./Shigella spp. using real-time PCR combined with guided culture.

Eine High-Throughput-Plattform für das Screening von Salmonella spp. /Shigella spp.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella ...

Opsonophagocytic Killing Assay to Assess Immunological Responses Against Bacterial Pathogens

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental procedure in which phagocytic cells are co-cultured with bacterial units. The immune cells will phagocytose and kill the bacterial cultures in a complement-dependent manner. The efficiency of the immune-mediated cell killing is dependent on a number of factors and can be used to determine how different bacterial cultures compare with regard to resistance to cell death. In this way, the efficacy of potential immune-based therapeutics can be assessed against specific bacterial strains and/or serotypes. In this protocol, we describe a simplified OPKA that utilizes basic culture conditions and cell counting to determine bacterial cell viability after co-culture with treatment conditions and HL-60 immune cells. This method has been successfully utilized with a number of different pneumococcal serotypes, capsular and acapsular strains, and other bacterial species. The advantages of this OPKA protocol are its simplicity, versatility (as this assay is not limited to antibody treatments as opsonins), and minimization of time and reagents to assess basic experimental groups.

This opsonophagocytic killing assay is used to compare the ability of phagocytic immune cells to respond to and kill bacteria based on different treatments and/or conditions. Classically, this assay serves as the gold&#160;standard for assessing effector functions of antibodies raised against a bacterium as opsonin.

Opsonophagocytic Tötung Assay Immunreaktionen gegen bakterielle Krankheitserreger zu bewerten

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental ...

Immunohistochemistry Test for the Lyssavirus Antigen Detection from Formalin-Fixed Tissues

One of the primary diagnostic modalities for rabies is the detection of viral ribonucleoprotein (RNP) complex (antigen) in the infected tissue samples. While the direct fluorescent antibody (DFA) test or the direct rapid immunohistochemical test (DRIT) are most commonly utilized for the antigen detection, both tests require fresh and/or frozen tissues for impressions on slides prior to the antigen detection using antibodies. If samples are collected and fixed in formalin, neither test is optimal for the antigen detection, however, testing can be performed by conventional immunohistochemistry (IHC) after embedding in paraffin blocks and sectioning. With this IHC method, tissues are stained with anti-rabies antibodies, sections are deparaffinized, antigen retrieved by partial proteolysis or other methods, and incubated with primary and secondary antibodies. Antigens are stained using horseradish peroxidase / amino ethyl carbazole and counterstained with hematoxylin for the visualization using a light microscope. In addition to the specific antigen detection, formalin fixation offers other advantages like the determination of histological changes, relaxed conditions for specimen storage and transport (under ambient temperatures), ability to test retrospective cases and improved biological safety through the inactivation of infectious agents.

Here, we present an immunohistochemistry test protocol for the detection of rabies virus antigen as an alternative diagnostic test for formalin-fixed tissues.

Immunhistochemischer Test für den Lyssavirus-Antigennachweis aus formalinfixierten Geweben

One of the primary diagnostic modalities for rabies is the detection of viral ribonucleoprotein (RNP) complex (antigen) in the infected tissue samples. ...