עבודה זו נתמכה על ידי מענקים מהמכון הלאומי לבריאות (AI079442 וAI091918) הוענקו לSEFD

<ol>
	<li>Becker, L. A., Evans, S. N., Hutkins, R. W., Benson, A. K. <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+sigmaB+in+adaptation+of+Listeria+monocytogenes+to+growth+at+low+temperature.">Role of sigmaB in adaptation of Listeria monocytogenes to growth at low temperature.</a> Journal of Bacteriology. 182, 7083-7087 (2000).</li><li>Neunlist, M. R., 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=Effect+of+salting+and+cold-smoking+on+the+culturability,+viability,+and+virulence+of+Listeria+monocytogenes+strain+Scott+A.">Effect of salting and cold-smoking on the culturability, viability, and virulence of Listeria monocytogenes strain Scott A.</a> Journal of Food Protection. 68, 85-91 (2005).</li><li>Aureli, P., 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=An+outbreak+of+febrile+gastroenteritis+associated+with+corn+contaminated+by+Listeria+monocytogenes.">An outbreak of febrile gastroenteritis associated with corn contaminated by Listeria monocytogenes.</a> N. Engl. J. Med. 342, 1236-1241 (2000).</li><li>Dalton, C. B., 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=An+outbreak+of+gastroenteritis+and+fever+due+to+Listeria+monocytogenes+in+milk.">An outbreak of gastroenteritis and fever due to Listeria monocytogenes in milk.</a> N. Engl. J. Med. 336, 100-105 (1997).</li><li>Frye, D. 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=An+outbreak+of+febrile+gastroenteritis+associated+with+delicatessen+meat+contaminated+with+Listeria+monocytogenes.">An outbreak of febrile gastroenteritis associated with delicatessen meat contaminated with Listeria monocytogenes.</a> Clin. Infect. Dis. 35, 943-949 (2002).</li><li>Salamina, 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=A+foodborne+outbreak+of+gastroenteritis+involving+Listeria+monocytogenes.">A foodborne outbreak of gastroenteritis involving Listeria monocytogenes.</a> Epidemiol. Infect. 117, 429-436 (1996).</li><li>Mead, P. 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=Food-related+illness+and+death+in+the+United+States.">Food-related illness and death in the United States.</a> Emerging Infectious Diseases. 5, 607-625 (1999).</li><li>Wing, E. J., Gregory, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Listeria+monocytogenes:+Clinical+and+experimental+update.">Listeria monocytogenes: Clinical and experimental update.</a> The Journal of Infectious Disease. 185, S18-S24 (2002).</li><li>Condotta, S. A., Richer, M. J., Badovinac, V. P., Harty, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+CD8+T+cell+responses+with+Listeria+monocytogenes+infection.">Probing CD8 T cell responses with Listeria monocytogenes infection.</a> Advances in Immunology. 113, 51-80 (2012).</li><li>Disson, O., 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=Modeling+human+listeriosis+in+natural+and+genetically+engineered+animals.">Modeling human listeriosis in natural and genetically engineered animals.</a> Nat Protoc. 4, 799-810 (2009).</li><li>Czuprynski, C. J., Faith, N. G., Steinberg, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A/J+mice+are+susceptible+and+C57BL/6+mice+are+resistant+to+Listeria+monocytogenes+infection+by+intragastric+inoculation.">A/J mice are susceptible and C57BL/6 mice are resistant to Listeria monocytogenes infection by intragastric inoculation.</a> Infect. Immun. 71, 682-689 (2003).</li><li>Gajendran, 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=Regional+IFNgamma+expression+is+insufficient+for+efficacious+control+of+food-borne+bacterial+pathogens+at+the+gut+epithelial+barrier.">Regional IFNgamma expression is insufficient for efficacious control of food-borne bacterial pathogens at the gut epithelial barrier.</a> Int. Immunol. 19, 1075-1081 (2007).</li><li>Lecuit, 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=A+transgenic+model+for+listeriosis:+role+of+internalin+in+crossing+the+intestinal+barrier.">A transgenic model for listeriosis: role of internalin in crossing the intestinal barrier.</a> Science. 292, 1722-1725 (2001).</li><li>Pron, B., 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=Comprehensive+study+of+the+intestinal+stage+of+listeriosis+in+a+rat+ligated+ileal+loop+system.">Comprehensive study of the intestinal stage of listeriosis in a rat ligated ileal loop system.</a> Infect. Immun. 66, 747-755 (1998).</li><li>Wollert, T., 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=Extending+the+host+range+of+Listeria+monocytogenes+by+rational+protein+design.">Extending the host range of Listeria monocytogenes by rational protein design.</a> Cell. 129, 891-902 (2007).</li><li>Ghanem, B. o. u., N, E., 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=InlA+promotes+dissemination+of+Listeria+monocytogenes+to+the+mesenteric+lymph+nodes+during+food+borne+infection+of+mice.">InlA promotes dissemination of Listeria monocytogenes to the mesenteric lymph nodes during food borne infection of mice.</a> PLoS Pathogens. , (2012).</li><li>Kowal, M., Buda-Lewandowska, D., Plytycz, B., Styrna, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Day/night+food+consumption+in+mice+is+strain+and+age-dependent.">Day/night food consumption in mice is strain and age-dependent.</a> Folia Biol. (Krakow). 50, 1-3 (2002).</li><li>Freitag, N. E., Port, G. C., Miner, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Listeria+monocytogenes+-+from+saprophyte+to+intracellular+pathogen.">Listeria monocytogenes - from saprophyte to intracellular pathogen.</a> Nature reviews. Microbiology. 7, 623-628 (2009).</li><li>Camejo, 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=The+arsenal+of+virulence+factors+deployed+by+Listeria+monocytogenes+to+promote+its+cell+infection+cycle.">The arsenal of virulence factors deployed by Listeria monocytogenes to promote its cell infection cycle.</a> Virulence. 2, 379-394 (2011).</li></ol>

החוקרים מצהירים כי אין להם אינטרסים כלכליים מתחרים. כל הניסויים שתוארו כאן בוצעו בעמידה במשרד למעבדה לרווחת בעלי החיים (OLAW) באישור ICAUC באוניברסיטת קנטאקי.

עכברים טהורים אינם אחיד פתוחים להאכלה בכל שעות היום, והנכונות שלהם לאכול את הלחם המזוהם יהיו תלויים גם בסוג והזן של עכברי גיל 17. מניסיוננו, 6-9 B6 עכברים ישנים בשבוע הם פתוחים להאכלה בכל שעה ביום, אבל עכברי BALB לא לאכול חתיכת הלחם באופן עקבי אלא אם כן הוא הציע במהלך ה...

חיידקי ליסטריה הם חיידקים פתוגנים תאיים פקולטטיביים הגורמים לזיהומים בבני אדם שמקורן במזון. החיידקים עמידים בפני רבים של תהליכים המשמשים להגנת אספקת המזון שלנו, כגון ייבוש, המלחה, או 1,2 קירור וזיהומים מקושרים בדרך כלל ל, מזונות &quot;מוכן לאכילה&quot; מעובדים שאינם מחוממים לפני הצריכה . בכמה התפרצויות קודמות, מקור ל &#39; מזון מזוהם חיידקי-זוהה, והקבוצה המצומצמת של אנשים שנחשפו הייתה פיקוח הדוק 3-6. בדוגמאות אלה, מחלה קלינית באנשים בריאים נעה בין קיבה ומעיים קלים, הגבלה עצמית לדלקות מעיים ומערכתיות חמורות יותר שנזקק לאשפוז. L. זיהומי חיידקי באנשים שנפרצו חיסוניים, כולל שני תינוקות והקשישים, היו קשורים עם שיעור תמותה גבוה (25-30%), אפילו עם טיפול אנטיביוטי <sעד&gt; 7,8. מעט מאוד ידוע על המינון המדבק לL. חיידקי, או את גורמי המארח ששולטים ברגישות לזיהומים לאחר שידור אוראלי, בעיקר בשל חוסר מודל חיה קטן שמשחזר מגוון רחב זה של תוצאות זיהום. המודל הנפוץ ביותר של דלקת ליסטריה הוא חיסון (IV) תוך ורידי של עכברים. המודל הרביעי הוא לשעתקו מאוד, והיה מאוד שימושית לחקר תגובות תא T הן נאיביות וזיכרון במהלך זיהום 9,10. החסרון של המודל הרביעי הוא שהיא עוקפת את שלב העיכול של זיהום לחלוטין. אחרי שידור שמקורן במזון, רירית המעיים מספקת מחסום שמאט כנראה ומגביל את מספר החיידקים כי הרף יכול להפיץ לרקמות היקפיות. לעומת זאת, ניתן למצוא את כל הבידוד בטחול ובכבד בתוך דקות של IV ממשל, ובולוס הגדול הזה של אורגניזמים עשוי להציף ד חיסון מולדיםefenses ברקמות אלה. משמש זיהום אוראלי של עכברים על ידי gavage פחות נפוץ, כי מנות גדולות (10 -10 11 CFU 9) נדרשות בדרך כלל כדי להשיג קולוניזציה מעיים 10. כמו כן, חיסון (IG) intragastric עם מחט האכלה אינו יוצר תקופת שחזור של זיהום במערכת העיכול לפני ההתפשטות מערכתית. מעבדות אחדות דיווחו כי ל &#39; חיידקי מגיעים לטחול וכבד בתוך 4-12 שעות לאחר זיהום (HPI), בעוד שאחרים לא הראו התפשטות מערכתית עד 48 HPI 11-15. וריאציה מעבדה למעבדה זו עשויה להיות תוצאה של האופי הפולשני של IG חיסון, אשר יכול לגרום לטראומה קלה לרירית של הוושט, ולקדם את פלישת דם ישירה של החיידקים. לאחרונה פיתחנו מודל עכבר רומן של אוראלי L. חיידקי לזיהום שמחק באופן הדוק כל שלבי מחלה אנושית 16. הדבקה מתרחשת כאשר העכברים לבלוע חתיכות של המשךaminated מזון, תהליך שהוא לא טראומטי, ואינו דורש כישורים מיוחדים על ידי חוקרי מעבדה. לתקופה של זמן בדיד (36-48 שעות), ל &#39; חיידקי reproducibly ליישב רק במערכת העיכול, ובכך מאפשרים חקירה של המנגנונים המשמשים ליסטריה פתוגניים translocate פני רירית המעיים ולהפיץ לרקמות היקפיות. חשוב מכך, ניתן להשתמש במודל כדי ללמוד הבדלים בהתנגדות מולדת מארחת לזיהום. במחקר קודם, הראינו שBALB / ג / מאת / עכברי J היו רגישים מאוד ליסטריה שמקורן במזון, עם שכפול מעריכי של ל &#39; חיידקי המתרחשים במעיים, הטחול, הכבד וכיס מרה 16. לעומת זאת, עכברי C57BL / 6 היו עמידים לזיהום שמקורן במזון, עם התישבות זמנית בלבד של ל &#39; חיידקי המתרחשים בכל אחת מרקמות אלה. תכונה נוספת של המודל שמקורן במזון המחקה מחלה אנושית הדוק היא הפצה טבעיתלמוח התרחש בשלבים מאוחר יותר של הזיהום (dpi 5-7).

<table border="1">
	<tbody>
 <tr>
 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalog Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>Brain Heart Infusion Agar</td>
 <td>Difco</td>
 <td>BD-241830</td>
 <td></td>
 </tr>
 <tr>
 <td>Lithium chloride</td>
 <td>Sigma</td>
 <td>L9650</td>
 <td ></td>
 </tr>
 <tr>
 <td>Glycine</td>
 <td>Omnipur</td>
 <td>4840</td>
 <td ></td>
 </tr>
 <tr>
 <td>EDTA</td>
 <td>Gibco</td>
 <td>15575-038</td>
 <td ></td>
 </tr>
 <tr>
 <td>DTT</td>
 <td>Sigma</td>
 <td>D5545</td>
 <td ></td>
 </tr>
 <tr>
 <td>Collagenase, type IV</td>
 <td>Worthington</td>
 <td>LS004089</td>
 <td></td>
 </tr>
 <tr>
 <td>DNAse I</td>
 <td>Worthington</td>
 <td>LS002007</td>
 <td></td>
 </tr>
 <tr>
 <td>Diff-Quik</td>
 <td>Dade-Behring</td>
 <td>B4132-1A</td>
 <td></td>
 </tr>
 <tr>
 <td>PowerGen 1000 homogenizer</td>
 <td>Fisher</td>
 <td>14-261-06</td>
 <td></td>
 </tr>
 <tr>
 <td>stainless steel type 304 mesh #80</td>
 <td>Small Parts, Inc.</td>
 <td>CX-0080-C</td>
 <td></td>
 </tr>
 <tr>
 <td>Cytospin</td>
 <td>Statspin</td>
 <td>M801-22</td>
 <td></td>
 </tr>
	 </tbody>
 </table>

oral transmission of listeria monocytogenes in mice via ingestion of contaminated food

חיידקי L. הם חיידקים פתוגנים תאיים פקולטטיביים הגורמים לזיהומים בבני אדם שמקורן במזון. מעט מאוד ידוע על שלב העיכול של ליסטריה בשל חוסר מודל חיה קטן המחקה מחלה אנושית באופן הדוק. מאמר זה מתאר מודל עכבר חדשני להעברה אוראלית של ל &#39; חיידקי. שימוש במודל זה, עכברים שהוזנו ל חיידקי מזוהמים יש לחם שלב דיסקרטי של זיהום במערכת העיכול, ואחריו בדרגות שונות של התפשטות מערכתית בזנים רגישים (BALB / ג / מאת / י) או עמידים (C57BL / 6) עכבר. בשלבים מאוחר יותר של הזיהום, הפצתו לכיס המרה והמוח הוא ציין. מודל שמקורן במזון של ליסטריה הוא לשעתקו מאוד, אינו דורש כישורים מיוחדים, וניתן להשתמש בו במגוון רחב של חיידקים ובודד זני עכבר מעבדה. ככזה, הוא המודל האידיאלי ללמוד שתי האסטרטגיות ארסיות בשימוש על ידי ל &#39; חיידקי </em&gt; כדי לקדם את התישבות במעיים, כמו גם את תגובת המארח למזון זיהום חיידקי פולשני נישא.

מושבות חיידקי L. תהיה גלויות על BHI / L + G צלחות לאחר הדגירה 36-48 שעות ב 37 ° C. יש מושבות מראה חלק, בצורת כיפה שמנת לבנה (איור 1 א). צמיחה תהיה עכבות עבור רוב חיידקי המעיים, אבל זה נפוץ לראות כמה מושבות שאינן L. חיידקי, במיוחד כאשר ציפוי מעי דק או מעי גס ישירות ל?...

Watch this Scientific Journal Video about Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food at JoVE.com

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

מאמר זה מתאר שיטה חדשה לזיהום אוראלי של עכברים באמצעות<em&gt; חיידקי ליסטריה</em&gt;-מזון מזוהם. הפרוטוקול יכול בקלות להיות מותאם לשימוש עם חיידקים פתוגנים שמקורן במזון אחר.

הילוכים אוראלי של<em&gt; חיידקי ליסטריה</em&gt; בעכברים באמצעות בליעה של מזון מזוהם

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the ...

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Immunology and Infection

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

19.1K Views.  University of Kentucky. מאמר זה מתאר שיטה חדשה לזיהום אוראלי של עכברים באמצעות חיידקי ליסטריה-מזון מזוהם. הפרוטוקול יכול בקלות להיות מותאם לשימוש עם חיידקים פתוגנים שמקורן במזון אחר.

Video: Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of Listeria, which results in systemic infection2. After injection, Listeria quickly disseminates to the spleen and liver due to uptake by CD8&alpha;+ dendritic cells and Kupffer cells3,4. Once phagocytosed, various bacterial proteins enable Listeria to escape the phagosome, survive within the cytosol, and infect neighboring cells5. During the first three days of infection, different innate immune cells (e.g. monocytes, neutrophils, NK cells, dendritic cells) mediate bactericidal mechanisms that minimize Listeria proliferation. CD8+ T cells are subsequently recruited and responsible for the eventual clearance of Listeria from the host, typically within 10 days of infection6.
Successful clearance of Listeria from infected mice depends on the appropriate onset of host immune responses6	. There is a broad range of sensitivities amongst inbred mouse strains7,8. Generally, mice with increased susceptibility to Listeria infection are less able to control bacterial proliferation, demonstrating increased bacterial load and/or delayed clearance compared to resistant mice. Genetic studies, including linkage analyses and knockout mouse strains, have identified various genes for which sequence variation affects host responses to Listeria infection6,8-14. Determination and comparison of infection kinetics between different mouse strains is therefore an important method for identifying host genetic factors that contribute to immune responses against Listeria. Comparison of host responses to different Listeria strains is also an effective way to identify bacterial virulence factors that may serve as potential targets for antibiotic therapy or vaccine design.
We describe here a straightforward method for measuring bacterial load (colony forming units [CFU] per tissue) and preparing single-cell suspensions of the liver and spleen for FACS analysis of immune responses in Listeria-infected mice. This method is particularly useful for initial characterization of Listeria infection in novel mouse strains, as well as comparison of immune responses between different mouse strains infected with Listeria. We use the Listeria monocytogenes EGD strain15 that, when cultured on blood agar, exhibits a characteristic halo zone around each colony due to &beta;-hemolysis1 (Figure 1). Bacterial load and immune responses can be determined at any time-point after infection by culturing tissue homogenate on blood agar plates and preparing tissue cell suspensions for FACS analysis using the protocols described below. We would note that individuals who are immunocompromised or pregnant should not handle Listeria, and the relevant institutional biosafety committee and animal facility management should be consulted before work commences.

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Listeria monocytogenes is a model organism for studying immune responses and genetic susceptibility to intracellular bacteria in mice. This method enables one to measure bacterial load and generate single-cell suspensions of the liver and spleen from mice for FACS analysis to determine changes in immune cells due to Listeria infection.

מדידת עומס בקטריאלי ותגובות החיסון של עכברים נגועים עם חיידקי ליסטריה</em

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of ...

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Bacterial intracellular pathogens can be conceived as molecular tools to dissect cellular signaling cascades due to their capacity to exquisitely manipulate and subvert cell functions which are required for the infection of host target tissues. Among these bacterial pathogens, Listeria monocytogenes is a Gram positive microorganism that has been used as a paradigm for intracellular parasitism in the characterization of cellular immune responses, and which has played instrumental roles in the discovery of molecular pathways controlling cytoskeletal and membrane trafficking dynamics. In this article, we describe a robust microscopical assay for the detection of late cellular infection stages of L. monocytogenes based on the fluorescent labeling of InlC, a secreted bacterial protein which accumulates in the cytoplasm of infected cells; this assay can be coupled to automated high-throughput small interfering RNA screens in order to characterize cellular signaling pathways involved in the up- or down-regulation of infection.

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Listeria monocytogenes is a Gram positive bacterial pathogen frequently used as a major model for the study of intracellular parasitism. Imaging late L. monocytogenes infection stages within the context of small-interfering RNA screens allows for the global study of cellular pathways required for bacterial infection of target host cells.

ההדמיה InlC הפרשה לחקר זיהום נייד על ידי פתוגן החיידקים<em&gt; חיידקי ליסטריה</em

Bacterial intracellular  pathogens can be conceived as molecular tools to dissect cellular signaling  cascades due to their capacity to exquisitely ...

Assessing Bacterial Invasion of Cardiac Cells in Culture and Heart Colonization in Infected Mice Using Listeria monocytogenes

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is capable of causing serious invasive infections in immunocompromised patients, the elderly, and pregnant women. The most common manifestations of listeriosis in humans include meningitis, encephalitis, and fetal abortion. A significant but much less documented sequelae of invasive L. monocytogenes infection involves the heart. The death rate from cardiac illness can be up to 35% despite treatment, however very little is known regarding L. monocytogenes colonization of cardiac tissue and its resultant pathologies. In addition, it has recently become apparent that subpopulations of L. monocytogenes have an enhanced capacity to invade and grow within cardiac tissue. This protocol describes in detail in vitro and in vivo methods that can be used for assessing cardiotropism of L. monocytogenes isolates. Methods are presented for the infection of H9c2 rat cardiac myoblasts in tissue culture as well as for the determination of bacterial colonization of the hearts of infected mice. These methods are useful not only for identifying strains with the potential to colonize cardiac tissue in infected animals, but may also facilitate the identification of bacterial gene products that serve to enhance cardiac cell invasion and/or drive changes in heart pathology. These methods also provide for the direct comparison of cardiotropism between multiple L. monocytogenes strains.

Assessing Bacterial Invasion of Cardiac Cells in Culture and Heart Colonization in Infected Mice Using Listeria monocytogenes

Listeria monocytogenes causes fetal infections in pregnant women and meningitis in susceptible populations. Subpopulations of bacteria can colonize cardiac tissue, causing myocarditis in patients and laboratory animals. Here we present a protocol that describes how to assess L. monocytogenes cardiac cell invasion in vitro and cardiac colonization in infected animals.

הערכת פלישת חיידקים לתאי לב בתרבות וקולוניזציה של הלב בעכברים נגועים באמצעות מונוציטוגנים ליסטריה

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is capable of causing serious invasive infections in immunocompromised ...

Transformation of Probiotic Yeast and Their Recovery from Gastrointestinal Immune Tissues Following Oral Gavage in Mice

Development of recombinant oral therapy would allow for more direct targeting of the mucosal immune system and improve the ability to combat gastrointestinal disorders. Adapting probiotic yeast in particular for this approach carries several advantages. These strains have not only the potential to synthesize a wide variety of complex heterologous proteins but are also capable of surviving and protecting those proteins during transit through the intestine. Critically, however, this approach requires expertise in many diverse laboratory techniques not typically used in tandem. Furthermore, although individual protocols for yeast transformation are well characterized for commonly used laboratory strains, emphasis is placed here on alternative approaches and the importance of optimizing transformation for less well characterized probiotic strains. Detailing these methods will help facilitate discussion as to the best approaches for testing probiotic yeast as oral drug delivery vehicles and indeed serve to advance the development of this novel strategy for gastrointestinal therapy.

Presented here is a unified description of techniques that can be used to develop, transform, administer, and test heterologous protein expression of the probiotic yeast Saccharomyces boulardii.

טרנספורמציה של שמרים פרוביוטיים ושחזור שלהם מרקמות העיכול החיסון בעקבות Gavage אוראלי עכברים

Development of recombinant oral therapy would allow for more direct targeting of the mucosal immune system and improve the ability to combat ...

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

Analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. However, isolating bacterial RNA from infected cells or tissues is a challenging task, since mammalian RNA mostly dominates the lysates of infected cells. Here we describe an optimized method for RNA isolation of Listeria monocytogenes bacteria growing within bone marrow derived macrophage cells. Upon infection, cells are mildly lysed and rapidly filtered to discard most of the host proteins and RNA, while retaining intact bacteria. Next, bacterial RNA is isolated using hot phenol-SDS extraction followed by DNase treatment. The extracted RNA is suitable for gene transcription analysis by multiple techniques. This method is successfully employed in our studies of Listeria monocytogenes gene regulation during infection of macrophage cells 1-4. The protocol can be easily modified to study other bacterial pathogens and cell types.

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

Here we describe a method for bacterial RNA isolation from Listeria monocytogenes bacteria growing inside murine macrophages. This technique can be used with other intracellular pathogens and mammalian host cells.

RNA טיהור מן intracellularly Grown<em&gt; חיידקי ליסטריה</em&gt; בתאי Macrophage

Analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. ...

Experimental Infection with Listeria monocytogenes as a Model for Studying Host Interferon-&#947; Responses

L. monocytogenes is a gram-positive bacterium that is a cause of food borne disease in humans. Experimental infection of mice with this pathogen has been highly informative on the role of innate and adaptive immune cells and specific cytokines in host immunity against intracellular pathogens. Production of IFN-&#947; by innate cells during sublethal infection with L. monocytogenes is important for activating macrophages and early control of the pathogen1-3. In addition, IFN-&#947; production by adaptive memory lymphocytes is important for priming the activation of innate cells upon reinfection4. The L. monocytogenes infection model thus serves as a great tool for investigating whether new therapies that are designed to increase IFN-&#947; production have an impact on IFN-&#947; responses in vivo and have productive biological effects such as increasing bacterial clearance or improving mouse survival from infection. Described here is a basic protocol for how to conduct intraperitoneal infections of C57BL/6J mice with the EGD strain of L. monocytogenes and to measure IFN-&#947; production by NK cells, NKT cells, and adaptive lymphocytes by flow cytometry. In addition, procedures are described to: (1) grow and prepare the bacteria for inoculation, (2) measure bacterial load in the spleen and liver, and (3) measure animal survival to endpoints. Representative data are also provided to illustrate how this infection model can be used to test the effect of specific agents on IFN-&#947; responses to L. monocytogenes and survival of mice from this infection.

Experimental Infection with &lt;em&gt;Listeria monocytogenes&lt;/em&gt; as a Model for Studying Host Interferon-&amp;#947; Responses

This protocol describes how to inoculate C57BL/6J mice with the EGD strain of Listeria monocytogenes (L. monocytogenes) and to measure interferon-&#947; (IFN-&#947;) responses by natural killer (NK) cells, natural killer T (NKT) cells, and adaptive T lymphocytes post-infection. This protocol also describes how to conduct survival studies in mice after infection with a modified LD50 dose of the pathogen.

זיהום הניסיון עם<em&gt; חיידקי ליסטריה</em&gt; כמודל תגובות לימוד מארח אינטרפרון-γ

L. monocytogenes is a gram-positive bacterium that is a cause of food borne disease in humans. Experimental infection of mice with this pathogen has been ...

An In Vitro Caseum Binding Assay that Predicts Drug Penetration in Tuberculosis Lesions

The eradication of tuberculosis disease requires drug regimens that can penetrate the multiple layers of complex pulmonary lesions. Drug distribution in the caseous cores of cavities and lesions is especially crucial because they harbor subpopulations of drug-tolerant bacteria also commonly referred to as persisters. Existing methods for the measurement of drug penetration in tuberculosis lesions involve costly and time-consuming in vivo pharmacokinetic studies coupled to bioanalytical or imaging techniques. The in vitro measurement of drug binding to caseum macromolecules was proposed as an alternative to such techniques since this binding hinders the passive diffusion of drug molecules through caseum. Rapid equilibrium dialysis is a fast and reliable system for performing plasma protein and tissue binding studies. In this protocol, we used a rapid equilibrium dialysis (RED) device to measure drug binding to homogenates of caseum that is excised from the lesions and cavities of tuberculosis-infected rabbits. The protocol also describes how to generate a surrogate matrix from lipid loaded THP-1 macrophages to use in place of caseum. This caseum/surrogate binding assay is an important tool in tuberculosis drug discovery and can be adapted to help study drug distribution in lesions or abscesses caused by other diseases.

An In Vitro Caseum Binding Assay that Predicts Drug Penetration in Tuberculosis Lesions

Here we describe a rapid equilibrium dialysis (RED) method to measure drug binding to caseum from pulmonary tuberculosis lesions and cavities. The protocol is also used with a foamy macrophage-derived matrix that is an effective surrogate to caseum.

An<em&gt; במבחנה</em&gt; Assay מחייב Assay כי חוזה חדירה לסמים בשחפת נגעים

The eradication of tuberculosis disease requires drug regimens that can penetrate the multiple layers of complex pulmonary lesions. Drug distribution in ...

Listeria monocytogenes Infection of the Brain

Listeria monocytogenes is an intracellular bacterial pathogen that is frequently associated with food-borne infection. The ability of&#160;L. monocytogenes to cross the blood-brain barrier (BBB) is concerning as it can lead to life-threatening meningitis and encephalitis. The BBB protects the brain microenvironment from various toxic metabolites and microbial pathogens found in the blood following infection, and therefore supports brain homeostasis. The mechanisms by which L. monocytogenes present in the bloodstream cross the BBB to cause brain infections are not fully understood and there is also a lack of a robust model system to study brain infections by L. monocytogenes. Here, we present a simple mouse infection model to determine whether bacteria have crossed the BBB and to quantitate the burden of bacteria that have colonized the brain in vivo. In this method, animals were infected intravenously with L. monocytogenes and were humanely euthanized by exposure to CO2 followed by cervical dislocation. Cardiac perfusion of the animals was performed prior to harvesting infected organs. Blood was collected before perfusion and the number of bacteria per organ or mL of blood was determined by plating dilutions of the blood or organ homogenates on agar plates and counting the number of colonies formed. This method can be used to study novel receptor-ligand interactions that enhance infection of the brain by L. monocytogenes and can be easily adapted for the study of multiple bacterial pathogens.

Listeria monocytogenes Infection of the Brain

During infection, Listeria monocytogenes is capable of crossing the blood-brain barrier to colonize the brain. In this protocol, we demonstrate how to assess bacterial colonization of organs following infection of mice. A procedure to perform whole organ perfusion for specific determination of bacterial numbers in the brain parenchyma is provided.

ליסטריה דלקת של המוח

Listeria monocytogenes is an intracellular bacterial pathogen that is frequently associated with food-borne infection. The ability of&#160;L. ...

Imaging of In Situ Interferon Gamma Production in the Mouse Spleen following Listeria monocytogenes Infection

Cytokines are small proteins secreted by cells, mediating cell-cell communications that are crucial for effective immune responses. One characteristic of cytokines is their pleiotropism, as they are produced by and can affect a multitude of cell types. As such, it is important to understand not only which cells are producing cytokines, but also in which environment they do so, in order to define more specific therapeutics. Here, we describe a method to visualize cytokine production in situ following bacterial infection. This technique relies on imaging cytokine-producing cells in their native environment by confocal microscopy. To do so, tissue sections are stained for markers of multiple cell types together with a cytokine stain. Key to this method, cytokine secretion is blocked directly in vivo before harvesting the tissue of interest, allowing for detection of the cytokine that accumulated inside the producing cells. The advantages of this method are multiple. First, the microenvironment in which cytokines are produced is preserved, which could ultimately inform on the signals required for cytokine production and the cells affected by those cytokines. In addition, this method gives an indication of the location of the cytokine production in vivo, as it does not rely on artificial in vitro re-stimulation of the producing cells. However, it is not possible to simultaneously analyze cytokine downstream signaling in cells that receive the cytokine. Similarly, the cytokine signals observed correspond&#160;only to the time-window during which cytokine secretion was blocked. While we describe the visualization of the cytokine Interferon (IFN) gamma in the spleen following mouse infection by the intracellular bacteria Listeria monocytogenes, this method could potentially be adapted to the visualization of any cytokine in most organs.

Imaging of In Situ Interferon Gamma Production in the Mouse Spleen following Listeria monocytogenes Infection

Here, we describe a simple confocal imaging method to visualize the in situ localization of cells secreting the cytokine Interferon gamma in murine secondary lymphoid organs. This protocol can be extended for the visualization of other cytokines in diverse tissues.

הדמיה של אינטרפרון באתרו הפקת גמא בטחול העכבר בעקבות זיהום יסטריה חיידקי

Cytokines are small proteins secreted by cells, mediating cell-cell communications that are crucial for effective immune responses. One characteristic of ...

Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery

Neisseria meningitidis (meningococcus) is a narrow-host-range microorganism, globally recognized as the leading cause of bacterial meningitis. Meningococcus is a transient colonizer of human nasopharynx of approximately 10% of healthy subject. In particular circumstances, it acquires an invasive ability to penetrate the mucosal barrier and invades the bloodstream causing septicaemia. In the latest case, fulminating sepsis could arise even without the consequent development of meningitis. Conversely, bacteria could poorly multiply in the bloodstream, cross the blood brain barrier, reach the central nervous system, leading to fulminant meningitis. The murine models of bacterial meningitis represent a useful tool to investigate the host-pathogen interactions and to analyze the pathogenetic mechanisms responsible for this lethal disease. Although, several experimental model systems have been evaluated over the last decades, none of these were able to reproduce the characteristic pathological events of meningococcal disease. In this experimental protocol, we describe a detailed procedure for the induction of meningococcal meningitis in a mouse model based on the intracisternal inoculation of bacteria. The peculiar signs of human meningitis were recorded in the murine host through the assessment of clinical parameters (e.g., temperature, body weight), evaluation of survival rate, microbiological analysis and histological examination of brain injury. When using intracisternal (i.cist.) inoculum, meningococci complete delivery directly into cisterna magna, leading to a very efficient meningococcal replication in the brain tissue. A 1,000-fold increase of viable count of bacteria is observed in about 18 h. Moreover, meningococci are also found in the spleen, and liver of infected mice, suggesting that the liver may represent a target organ for meningococcal replication.

Here, we describe a method to induce meningococcal meningitis through an intracisternal route of infection in adult mice. We present a step by step protocol of meningococcal infection from the preparation of inoculum to the intracisternal infection; then record the animal survival and evaluate the bacterial loads in murine tissues.