وقد دعم هذا العمل منح دائرة الصحة العامة منظمة العفو الدولية 41816 وAI099339 (N.E.F.) وF31AI094886-01 (P.D.M.) من المعهد الوطني للتنمية الدولية. وتقع المحتويات على عاتق المؤلفين فقط ولا تمثل بالضرورة الآراء الرسمية لمصادر التمويل.

<ol>
	<li>Freitag, N. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+hot+dogs+to+host+cells:+how+the+bacterial+pathogen+Listeria+monocytogenes+regulates+virulence+gene+expression.">From hot dogs to host cells: how the bacterial pathogen Listeria monocytogenes regulates virulence gene expression.</a> Future Microbiol. 1, 89-101 (2006).</li><li>Drevets, D. A., Bronze, M. S. <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:+epidemiology,+human+disease,+and+mechanisms+of+brain+invasion.">Listeria monocytogenes: epidemiology, human disease, and mechanisms of brain invasion.</a> FEMS Immunol Med Microbiol. 53, 151-165 (2008).</li><li>Farber, J. M., Peterkin, P. I. <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.+a+food-borne+pathogen.">Listeria monocytogenes. a food-borne pathogen.</a> Microbiol. Rev. 55, 476-511 (1991).</li><li>Lecuit, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+how+Listeria+monocytogenes+targets+and+crosses+host+barriers.">Understanding how Listeria monocytogenes targets and crosses host barriers.</a> Clin Microbiol Infect. 11, 430-436 (2005).</li><li>Lecuit, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+listeriosis+and+animal+models.">Human listeriosis and animal models.</a> Microbes Infect. 9, 1216-1225 (2007).</li><li>Bou Ghanem, E. 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=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 Pathog. 8, e1003015 (2012).</li><li>Melton-Witt, J. A., Rafelski, S. M., Portnoy, D. A., Bakardjiev, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+infection+with+signature-tagged+Listeria+monocytogenes+reveals+organ-specific+growth+and+dissemination+routes+in+guinea+pigs.">Oral infection with signature-tagged Listeria monocytogenes reveals organ-specific growth and dissemination routes in guinea pigs.</a> Infect Immun. 80, 720-732 (2012).</li><li>Alonzo, F., Bobo, L. D., Skiest, D. J., Freitag, N. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+subpopulations+of+Listeria+monocytogenes+with+enhanced+invasion+of+cardiac+cells.">Evidence for subpopulations of Listeria monocytogenes with enhanced invasion of cardiac cells.</a> J Med Microbiol. , (2011).</li><li>Adler, 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=Inflammatory+pseudotumor+of+the+heart+caused+by+Listeria+monocytogenes+infection.">Inflammatory pseudotumor of the heart caused by Listeria monocytogenes infection.</a> J Infect. 58, 161-163 (2009).</li><li>Antolin, J., Gutierrez, A., Segoviano, R., Lopez, R., Ciguenza, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endocarditis+due+to+Listeria:+description+of+two+cases+and+review+of+the+literature.">Endocarditis due to Listeria: description of two cases and review of the literature.</a> Eur J Intern Med. 19, 295-296 (2008).</li><li>Brouqui, P., Raoult, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endocarditis+due+to+rare+and+fastidious+bacteria.">Endocarditis due to rare and fastidious bacteria.</a> Clin Microbiol Rev. 14, 177-207 (2001).</li><li>Brusch, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+infections+in+the+immunosuppressed+patient.">Cardiac infections in the immunosuppressed patient.</a> Infect Dis Clin North Am. 15, 613-638 (2001).</li><li>McCue, M. J., Moore, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myocarditis+with+microabscess+formation+caused+by+Listeria+monocytogenes+associated+with+myocardial+infarct.">Myocarditis with microabscess formation caused by Listeria monocytogenes associated with myocardial infarct.</a> Hum Pathol. 10, 469-472 (1979).</li><li>Menard, C., 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=Modulation+of+L-type+calcium+channel+expression+during+retinoic+acid-induced+differentiation+of+H9C2+cardiac+cells.">Modulation of L-type calcium channel expression during retinoic acid-induced differentiation of H9C2 cardiac cells.</a> J Biol Chem. 274, 29063-29070 (1999).</li><li>Czuprynski, C. J. <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:+silage,+sandwiches+and+science.">Listeria monocytogenes: silage, sandwiches and science.</a> Anim Health Res Rev. 6, 211-217 (2005).</li><li>Grundler, 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=The+surface+proteins+InlA+and+InlB+are+interdependently+required+for+polar+basolateral+invasion+by+Listeria+monocytogenes+in+a+human+model+of+the+blood-cerebrospinal+fluid+barrier.">The surface proteins InlA and InlB are interdependently required for polar basolateral invasion by Listeria monocytogenes in a human model of the blood-cerebrospinal fluid barrier.</a> Microbes Infect. 15, 291-301 (2013).</li><li>Zeldovich, V. B., Robbins, J. R., Kapidzic, M., Lauer, P., Bakardjiev, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invasive+extravillous+trophoblasts+restrict+intracellular+growth+and+spread+of+Listeria+monocytogenes.">Invasive extravillous trophoblasts restrict intracellular growth and spread of Listeria monocytogenes.</a> PLoS Pathog. 7, e1002005 (2011).</li><li>Kimes, B. W., Brandt, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+a+clonal+muscle+cell+line+from+rat+heart.">Properties of a clonal muscle cell line from rat heart.</a> Experimental cell research. 98, 367-381 (1976).</li><li>McMullen, P. D., 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=Genome+sequence+of+Listeria+monocytogenes+07PF0776,+a+cardiotropic+serovar+4b+strain.">Genome sequence of Listeria monocytogenes 07PF0776, a cardiotropic serovar 4b strain.</a> J Bacteriol. 194, 3552 (2012).</li></ol>

ولا يبلغ المؤلفان عن وجود مصالح مالية متنافسة.

L. monocytogenes هو مسببات الأمراض البشرية واسعة الانتشار وتتميز بشكل جيد، وقادرة على التسبب في عدد من مظاهر المرض المختلفة15. وقد وصفت البكتيريا في وقت سابق لقدرتها على نقل عبر الحواجز، مثل حاجز الدم في الدماغ وحواجز المشيمة والجنين، من أجل الوصول واستعمار الجهاز العصبي المركزي والجن...

الليستيريا monocytogenes هو الممرض داخل الخلايا إيجابية غرام قادرة على التسبب في مرض شديد في السكان المعرضين، بما في ذلك كبار السن، والنساء الحوامل، والأشخاص المصابين بفيروس نقص المناعة البشرية / الإيدز، والأشخاص الذين يتلقون العلاج الكيميائي1. وكثيرا ما تكون العدوى بين هذه المجموعات نتيجة تناول منتجات غذائية ملوثة، وترتبط معظم الإصابات بتفشي المرض على نطاق واسع المنقول بالأغذية2.3. في البشر والثدييات الأخرى ، L. monocytogenes قادرة على نقل عبر الحدود الظهارية للأمعاء الدقيقة ، وبعد ذلك يتم نقلها إلى الكبد4،5. وتشير النماذج الحيوانية إلى أن البكتيريا المبتلعة تتكرر داخل الزغب المعوي وتمر إلى الكبد عبر الوريد البوابي أو تنتشر عبر الغدد الليمفاوية الميسنتريكية في مجرى الدم، مما يؤدي إلى انتشار الدم إلى الكبد والطحال6،7. في الكبد والطحال ، والبكتيريا قادرة على التوسط امتصاص في كل من الخلايا الفصيلية المهنية وكذلك الخلايا parenchymal المقيمين ، ويقيم بسرعة العدوى داخل هذه الأجهزة. مع زيادة الحمل البكتيري ، يتم تشتيت العديد من البكتيريا مرة أخرى في الدم ، حيث تكون قادرة على استعمار المزيد من الأنسجة المعرضة بما في ذلك الجهاز العصبي المركزي والمشيمة (عند وجودها). استعمار هذه المواقع يحول دون المظاهر الأكثر شيوعا من الليستريات في البشر، بما في ذلك التهاب السحايا والتهاب الدماغ، والإجهاضالجنيني 2.
وقد تبين مؤخرا أن الخلايا الفرعية المختارة من L. monocytogenes لديها قدرة معززة على غزو وتكرار داخل الأنسجة القلبية8. وتتنوع مظاهر مشاركة القلب، وتتراوح بين التهاب الشغاف والتهاب التامور، لالتهاب عضلة القلب فولمينانت كاملة مع تشوهات التوصيل9-13. العدد الإجمالي لحالات القلب أحادية السيتوجينات L. في السنة منخفض ولكن قد يكون أقل من التقدير لأن هذا الجانب من العدوى غير معترف به بشكل جيد بشكل عام. استعمار القلب من قبل مسببات الأمراض غالبا ما يتطلب الاستعداد المضيف مثل الضرر الصمامي الموجودة من قبل أو صمامات القلب الاصطناعية. ومع ذلك، هناك عزلات من L. monocytogenes التي تم تحديدها التي هي ملحوظة لقدرتها على استعمار قلوب الحيوانات المصابة في غياب أي تلف القلب و / أو شذوذ8.
هنا توصف في المختبر وفي أساليب الجسم الحي لتقييم الاستعمار البكتيري للأنسجة القلبية داخل الحيوانات المصابة باستخدام المقايسات الغزو في زراعة الأنسجة، فضلا عن العدوى الحيوانية الحية. وقد أثبتت هذه الطرق فائدتها ليس فقط لتحديد السلالات التي لديها القدرة على استعمار الأنسجة القلبية في الحيوانات المصابة ، ولكن ينبغي أيضا أن تكون مفيدة لتحديد المنتجات الجينية البكتيرية التي تعمل على تعزيز غزو خلايا القلب و / أو تؤدي إلى تغييرات في أمراض القلب. هذه الأساليب تسهل مقارنة القلب بين سلالات متعددة. للأساليب الموصوفة هنا, L. monocytogenes 10403S يستخدم كممثل مدروسة جيدا من سلالة غير القلب الاستوائية ويتم استخدام عزل السريرية 07PF0776 كمثال تمثيلي لسلالة القلب والتروبيك. وقد تم اختيار هذين النوعين لتوفير مقارنة للغزو البكتيري للخلايا القلبية في المختبر والاستعمار من قلوب الفئران المصابة في الجسم الحي. عزل 07PF0776 هو عزل السريرية تعافى من خراج التدخلية التي تسببت في عدم انتظام ضربات القلب القاتلة في فيروس نقص المناعة البشرية + المريض8. L. قد تختلف عزلات أحادية السيتوجينات في إمكاناتها الفوعة، ونظرا لميل ليستريا لإصابة الأشخاص مع كبت المناعة والنساء الحوامل، والأشخاص داخل هذه المجموعات السكانية يجب توخي الحذر أثناء تقييم العزلات السريرية المختلفة.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Difco</td>
			<td>BHI Broth Base</td>
			<td>237200</td>
			<td>2KG of Brain Heart Infusion powder (without agar)</td>
		</tr>
		<tr>
			<td>Difco</td>
			<td>Agar</td>
			<td>214510</td>
			<td>2KG of Granulated Agar</td>
		</tr>
		<tr>
			<td>Difco</td>
			<td>BHI Agar</td>
			<td>241810</td>
			<td>2KG of Brain Heart Infusion Powder with 7.5% Agar</td>
		</tr>
		<tr>
			<td>in vitrogen</td>
			<td>LB Broth Base</td>
			<td>12975-084</td>
			<td>2KG of Luria Broth Base Powder (without agar)</td>
		</tr>
		<tr>
			<td>Fisher</td>
			<td>Glass Coverslips</td>
			<td>12-545-80</td>
			<td>12mm glass coverslips</td>
		</tr>
		<tr>
			<td>Falcon</td>
			<td>24-well Tissue Culture Plate</td>
			<td>35-3047</td>
			<td>24 Well, Plasma-treated Tissue Culture Plate</td>
		</tr>
		<tr>
			<td>Falcon</td>
			<td>14mL Polystyrene tube</td>
			<td>352051</td>
			<td>14mL Polystyrene tubes</td>
		</tr>
		<tr>
			<td>Falcon</td>
			<td>96-well U-bottom plate</td>
			<td>35-3077</td>
			<td>Non-tissue culture treated 96-well plate</td>
		</tr>
		<tr>
			<td>Corning</td>
			<td>0.05% Trypsin, 0.53 mM EDTA (1X)</td>
			<td>25-052-CI</td>
			<td>Stock solution of Trypsin EDTA for tissue culture</td>
		</tr>
		<tr>
			<td>Corning</td>
			<td>DMEM (High glucose, high pyruvate)</td>
			<td>15-013-CU</td>
			<td>DMEM media without FBS, glutamine, or antibiotics</td>
		</tr>
		<tr>
			<td>Corning</td>
			<td>Pen/Strep/Glut Solution</td>
			<td>30-009-CI</td>
			<td>Stock mixture of penicillin, streptomycin, and L-glutamine for tissue culture</td>
		</tr>
		<tr>
			<td>Corning</td>
			<td>Gentamicin</td>
			<td>30-005-CR</td>
			<td>50mg/mL Stock solution of Gentamicin for tissue culture</td>
		</tr>
		<tr>
			<td>Cellgro (Corning)</td>
			<td>L-Glutamine</td>
			<td>25005197</td>
			<td>Stock L-glutamine solution without antibiotics</td>
		</tr>
		<tr>
			<td>Denville</td>
			<td>75cm^2 Flask</td>
			<td>T1225</td>
			<td>75cm^2 tissue culture treated flask</td>
		</tr>
		<tr>
			<td>Denville</td>
			<td>1.5mL microcentrifuge tubes</td>
			<td>2013004</td>
			<td>1.5mL microcentrifuge tubes</td>
		</tr>
		<tr>
			<td>ATCC</td>
			<td>H9c2 Cardiac Myoblasts</td>
			<td>CRL-1446</td>
			<td>Rat cardiac myoblasts</td>
		</tr>
		<tr>
			<td>Hyclone</td>
			<td>Fetal Bovine Serum</td>
			<td>SH30070.63</td>
			<td>Fetal Bovine Serum</td>
		</tr>
	</tbody>
</table>

assessing bacterial invasion of cardiac cells in culture and heart colonization in infected mice using listeria monocytogenes

الليستيريا monocytogenes هو مسببات الأمراض داخل الخلايا إيجابية الغرام التي هي قادرة على التسبب في التهابات الغازية الخطيرة في المرضى الذين يعانون من نقص المناعة، وكبار السن، والنساء الحوامل. المظاهر الأكثر شيوعا من الليستريات في البشر تشمل التهاب السحايا والتهاب الدماغ والإجهاض الجنيني. وهناك تتمة كبيرة ولكن أقل توثيقا بكثير من العدوى L. monocytogenes الغازية ينطوي على القلب. يمكن أن يصل معدل الوفيات الناجمة عن مرض القلب إلى 35٪ على الرغم من العلاج ، ولكن لا يعرف سوى القليل جدا فيما يتعلق ب استعمار L. monocytogenes للأنسجة القلبية والأمراض الناتجة عنها. وبالإضافة إلى ذلك، أصبح من الواضح مؤخرا أن الاكتظاظ السكاني الفرعي من L. monocytogenes لديها قدرة معززة لغزو وتنمو داخل الأنسجة القلبية. يصف هذا البروتوكول بالتفصيل في المختبر وفي أساليب الجسم الحي التي يمكن استخدامها لتقييم cardiotropism من L. يعزل monocytogenes. وتقدم أساليب للعدوى من الخلايا العضلية القلبية الفئران H9c2 في زراعة الأنسجة، فضلا عن تحديد الاستعمار البكتيري لقلوب الفئران المصابة. هذه الأساليب مفيدة ليس فقط لتحديد السلالات التي يمكن أن تستعمر الأنسجة القلبية في الحيوانات المصابة ، ولكن قد تسهل أيضا تحديد المنتجات الجينية البكتيرية التي تعمل على تعزيز غزو خلايا القلب و / أو دفع التغيرات في أمراض القلب. هذه الأساليب توفر أيضا للمقارنة المباشرة من القلب بين سلالات متعددة L. monocytogenes.

إن عزلات مختارة من أحاديات الخلايا L. تظهر غزوا معززا لخلايا القلب في ثقافة الخلايا وفي نماذج الماوس للعدوى. ويبين الشكل 1 مثالا على كيفية ظهور المستعمرات البكتيرية بعد طلاء بقعة من تعليق على وسائل الإعلام أجار. تسمح هذه الطريقة بتقييم دقيق ل CFUs داخل العينة دون استخدام أعداد ك...

Watch this Scientific Journal Video about Assessing Bacterial Invasion of Cardiac Cells in Culture and Heart Colonization in Infected Mice Using Listeria monocytogenes at JoVE.com

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

الليستيريا monocytogenes يسبب التهابات الجنين في النساء الحوامل والتهاب السحايا في السكان المعرضين. يمكن أن تستعمر الاكتظاظ السكاني الفرعي للبكتيريا أنسجة القلب ، مما يسبب التهاب عضلة القلب في المرضى المختبر. هنا نقدم بروتوكولا يصف كيفية تقييم L. monocytogenes غزو الخلايا القلبية في المختبر والاستعمار القلبي في الحيوانات المصابة.

تقييم الغزو البكتيري لخلايا القلب في الثقافة والاستعمار القلب في الفئران المصابة باستخدام monocytogenes الليستيريا

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

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Immunology and Infection

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

5.4K Views.  College of Medicine, University of Illinois at Chicago. الليستيريا monocytogenes يسبب التهابات الجنين في النساء الحوامل والتهاب السحايا في السكان المعرضين. يمكن أن تستعمر الاكتظاظ السكاني الفرعي للبكتيريا أنسجة القلب ، مما يسبب التهاب عضلة القلب في المرضى المختبر. هنا نقدم بروتوكولا يصف كيفية تقييم L. monocytogenes غ?...

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

Assessing Stomatal Response to Live Bacterial Cells using Whole Leaf Imaging

Stomata are natural openings in the plant epidermis responsible for gas exchange between plant interior and environment. They are formed by a pair of guard cells, which are able to close the stomatal pore in response to a number of external factors including light intensity, carbon dioxide concentration, and relative humidity (RH). The stomatal pore is also the main route for pathogen entry into leaves, a crucial step for disease development. Recent studies have unveiled that closure of the pore is effective in minimizing bacterial disease development in Arabidopsis plants; an integral part of plant innate immunity. Previously, we have used epidermal peels to assess stomatal response to live bacteria (Melotto et al. 2006); however maintaining favorable environmental conditions for both plant epidermal peels and bacterial cells has been challenging. Leaf epidermis can be kept alive and healthy with MES buffer (10 mM KCl, 25 mM MES-KOH, pH 6.15) for electrophysiological experiments of guard cells. However, this buffer is not appropriate for obtaining bacterial suspension. On the other hand, bacterial cells can be kept alive in water which is not proper to maintain epidermal peels for long period of times. When an epidermal peel floats on water, the cells in the peel that are exposed to air dry within 4 hours limiting the timing to conduct the experiment. An ideal method for assessing the effect of a particular stimulus on guard cells should present minimal interference to stomatal physiology and to the natural environment of the plant as much as possible. We, therefore, developed a new method to assess stomatal response to live bacteria in which leaf wounding and manipulation is greatly minimized aiming to provide an easily reproducible and reliable stomatal assay. The protocol is based on staining of intact leaf with propidium iodide (PI), incubation of staining leaf with bacterial suspension, and observation of leaves under laser scanning confocal microscope. Finally, this method allows for the observation of the same live leaf sample over extended periods of time using conditions that closely mimic the natural conditions under which plants are attacked by pathogens.

We have developed a simple and reproducible protocol to access stomatal response to live bacteria. This method minimizes wounding and manipulation of the leaf as compared to the use of epidermal peels reported previously.

تقييم الاستجابة للعيش فوهي الخلايا البكتيرية باستخدام التصوير الجامعة ليف

Stomata are natural openings in the plant epidermis responsible for gas exchange between plant interior and environment. They are formed by a pair of ...

Using Luciferase to Image Bacterial Infections in Mice

Imaging is a valuable technique that can be used to monitor biological processes. In particular, the presence of cancer cells, stem cells, specific immune cell types, viral pathogens, parasites and bacteria can be followed in real-time within living animals 1-2. Application of bioluminescence imaging to the study of pathogens has advantages as compared to conventional strategies for analysis of infections in animal models3-4. Infections can be visualized within individual animals over time, without requiring euthanasia to determine the location and quantity of the pathogen. Optical imaging allows comprehensive examination of all tissues and organs, rather than sampling of sites previously known to be infected. In addition, the accuracy of inoculation into specific tissues can be directly determined prior to carrying forward animals that were unsuccessfully inoculated throughout the entire experiment. Variability between animals can be controlled for, since imaging allows each animal to be followed individually. Imaging has the potential to greatly reduce animal numbers needed because of the ability to obtain data from numerous time points without having to sample tissues to determine pathogen load3-4.
This protocol describes methods to visualize infections in live animals using bioluminescence imaging for recombinant strains of bacteria expressing luciferase. The click beetle (CBRLuc) and firefly luciferases (FFluc) utilize luciferin as a substrate5-6. The light produced by both CBRluc and FFluc has a broad wavelength from 500 nm to 700 nm, making these luciferases excellent reporters for the optical imaging in living animal models7-9. This is primarily because wavelengths of light greater than 600 nm are required to avoid absorption by hemoglobin and, thus, travel through mammalian tissue efficiently. Luciferase is genetically introduced into the bacteria to produce light signal10. Mice are pulmonary inoculated with bioluminescent bacteria intratracheally to allow monitoring of infections in real time. After luciferin injection, images are acquired using the IVIS Imaging System. During imaging, mice are anesthetized with isoflurane using an XGI-8 Gas Anethesia System. Images can be analyzed to localize and quantify the signal source, which represents the bacterial infection site(s) and number, respectively. After imaging, CFU determination is carried out on homogenized tissue to confirm the presence of bacteria. Several doses of bacteria are used to correlate bacterial numbers with luminescence. Imaging can be applied to study of pathogenesis and evaluation of the efficacy of antibacterial compounds and vaccines.

Methods for bioluminescence imaging of bacterial infections in living animals are decribed. Pathogens are modified to express luciferase allowing optical whole body imaging of infections in live animals. Animal models can be infected with luciferase expressing pathogens and the resulting course of disease visualized in real-time by bioluminescence imaging.

Luciferase به لالتهابات جرثومية في صورة الفئران

Imaging is a valuable technique that can be used to monitor biological processes.  In particular, the presence of cancer cells, stem cells, specific ...

Invasion of Human Cells by a Bacterial Pathogen

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be applied to the study of cell invasion by virtually any culturable bacterium. The stages at which specific aspects of invasion can be studied, such as the role of actin rearrangement or caveolae, will be highlighted. Host cells are grown in flasks and when ready for use are seeded into 24-well plates containing Thermanox coverslips. Using coverslips allows subsequent removal of the cells from the wells to reduce interference from serum proteins deposited onto the sides of the wells (to which S. aureus would attach). Bacteria are grown to the required density and washed to remove any secreted proteins (e.g. toxins). Coverslips with confluent layers of endothelial cells are transferred to new 24-well plates containing fresh culture medium before the addition of bacteria. Bacteria and cells are then incubated together for the required amount of time in 5% CO2 at 37&deg;C. For S. aureus this is typically between 15-90 minutes. Thermanox coverslips are removed from each well and dip-washed in PBS to remove unattached bacteria. If total associated bacteria (adherent and internalised) are to be quantified, coverslips are then placed in a fresh well containing 0.5% Triton X-100 in PBS. Gentle pipetting leads to complete cell lysis and bacteria are enumerated by serial dilution and plating onto agar. If the number of bacteria that have invaded the cells is needed, coverslips are added to wells containing 500 &mu;l tissue culture medium supplemented with gentamicin and incubation continued for 1 h, which will kill all external bacteria. Coverslips can then be washed, cells lysed and bacteria enumerated by plating onto agar as described above. If the experiment requires direct visualisation, coverslips can be fixed and stained for light, fluorescence or confocal microscopy or prepared for electron microscopy.

A general protocol for the study of invasion of host cells by a bacterial pathogen, focusing on Staphylococcus aureus and human endothelial cells.

غزو ​​الخلايا البشرية من قبل الممرض الجرثومي

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be ...

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.

قياس الحمولة الجرثومية والاستجابات المناعية في الفئران المصابة المستوحدة الليستيريا</em

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

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

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the gastrointestinal phase of listeriosis due to the lack of a small animal model that closely mimics human disease. This paper describes a novel mouse model for oral transmission of L. monocytogenes. Using this model, mice fed L. monocytogenes-contaminated bread have a discrete phase of gastrointestinal infection, followed by varying degrees of systemic spread in susceptible (BALB/c/By/J) or resistant (C57BL/6) mouse strains. During the later stages of the infection, dissemination to the gall bladder and brain is observed. The food borne model of listeriosis is highly reproducible, does not require specialized skills, and can be used with a wide variety of bacterial isolates and laboratory mouse strains. As such, it is the ideal model to study both virulence strategies used by L. monocytogenes to promote intestinal colonization, as well as the host response to invasive food borne bacterial infection.

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

This paper describes a novel method for oral infection of mice using Listeria monocytogenes-contaminated food. The protocol can readily be adapted for use with other food borne bacterial pathogens.

النقل الشفوي لل<em&gt; المستوحدة الليستيريا</em&gt; في الفئران عن طريق ابتلاع الطعام الملوث

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

Enteric Bacterial Invasion Of Intestinal Epithelial Cells In Vitro Is Dramatically Enhanced Using a Vertical Diffusion Chamber Model

The interactions of bacterial pathogens with host cells have been investigated extensively using in vitro cell culture methods. However as such cell culture assays are performed under aerobic conditions, these in vitro models may not accurately represent the in vivo environment in which the host-pathogen interactions take place. We have developed an in vitro model of infection that permits the coculture of bacteria and host cells under different medium and gas conditions. The Vertical Diffusion Chamber (VDC) model mimics the conditions in the human intestine where bacteria will be under conditions of very low oxygen whilst tissue will be supplied with oxygen from the blood stream. Placing polarized intestinal epithelial cell (IEC) monolayers grown in Snapwell inserts into a VDC creates separate apical and basolateral compartments. The basolateral compartment is filled with cell culture medium, sealed and perfused with oxygen whilst the apical compartment is filled with broth, kept open and incubated under microaerobic conditions. Both Caco-2 and T84 IECs can be maintained in the VDC under these conditions without any apparent detrimental effects on cell survival or monolayer integrity. Coculturing experiments performed with different C. jejuni wild-type strains and different IEC lines in the VDC model with microaerobic conditions in the apical compartment reproducibly result in an increase in the number of interacting (almost 10-fold) and intracellular (almost 100-fold) bacteria compared to aerobic culture conditions1. The environment created in the VDC model more closely mimics the environment encountered by C. jejuni in the human intestine and highlights the importance of performing in vitro infection assays under conditions that more closely mimic the in vivo reality. We propose that use of the VDC model will allow new interpretations of the interactions between bacterial pathogens and host cells.

Enteric Bacterial Invasion Of Intestinal Epithelial Cells In Vitro Is Dramatically Enhanced Using a Vertical Diffusion Chamber Model

Performing cell culture assays for investigating bacterial adhesion and invasion under aerobic conditions is usually unrepresentative of the in vivo environment. A Vertical Diffusion Chamber model allows study of interactions of the human pathogen Campylobacter jejuni with intestinal epithelial cells under more in vivo-like conditions, resulting in enhanced bacterial invasion.

الغزو الجرثومي المعوي الخلايا الظهارية المعوية<em&gt; في المختبر</em&gt; تتعزز بشكل كبير عن طريق دائرة إنتشار عمودي الموديل

The interactions of bacterial pathogens with host cells have been investigated extensively using in vitro cell culture methods. However as such cell ...

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.

التصوير InlC إفراز المعنية بالتحقيق في العدوى البكتيرية الخلوية من قبل الممرض<em&gt; المستوحدة الليستيريا</em

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

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the protocols described here use freshly isolated human peripheral blood mononuclear cells (PBMCs) or plasmacytoid dendritic cells (pDCs) to sense infections in either T cell line (MT4) or heterologous primary CD4+ T cells. In order to ensure proper sensing, it is essential that PBMC are isolated immediately after blood collection and that optimal percentage of infected T cells are used. Furthermore, multi-parametric flow cytometric staining can be used to confirm that PBMC samples contain the different cell lineages at physiological ratios. A number of controls can also be included to evaluate viability and functionality of pDCs. These include, the presence of specific surface markers, assessing cellular responses to known agonist of Toll-Like Receptors (TLR) pathways, and confirming a lack of spontaneous type-I interferon (IFN) production. In this system, freshly isolated PBMCs or pDCs are co-cultured with HIV-1 infected cells in 96 well plates for 18-22 hr. Supernatants from these co-cultures are then used to determine the levels of bioactive type-I IFNs by monitoring the activation of the ISGF3 pathway in HEK-Blue IFN-&#945;/&#946; cells. Prior and during co-culture conditions, target cells can be subjected to flow cytometric analysis to determine a number of parameters, including the percentage of infected cells, levels of specific surface markers, and differential killing of infected cells. Although, these protocols were initially developed to follow type-I IFN production, they could potentially be used to study other imuno-modulatory molecules released from pDCs and to gain further insight into the molecular mechanisms governing HIV-1 innate sensing.

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

Unlike cell-free HIV-1 particles, infected CD4+ T cells are effectively sensed by plasmacytoid dendritic cells (pDCs). This manuscript describes a method where peripheral blood mononuclear cells (PBMCs) or isolated pDCs are co-cultured with HIV-1 infected T cells to evaluate innate sensing by pDCs as assessed by release of type-I IFN.

تقييم الفطرية الاستشعار من HIV-1 CD4 المصابة<sup&gt; +</sup&gt; T الخلايا عن طريق الخلايا الجذعية بلازماوية الشكل باستخدام<em&gt; خارج الحي</em&gt; المشارك ثقافة النظام.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the ...

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 تنقية من داخل الخلية المزروعة<em&gt; المستوحدة الليستيريا</em&gt; في خلايا البلاعم

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.

العدوى التجريبية مع<em&gt; المستوحدة الليستيريا</em&gt; نموذجا لدراسة المضيف الردود انترفيرون 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 ...