Yazarlar teknik yardım SLO plazmid ve Jonathan Franks cömert hediye için anthrolysin O, Michael Caparon ve cömert bir hediye için Richard istirahat teşekkür etmek istiyorum. Bu çalışma NIH hibe T32CA82084 (PAK) ve R01AI072083 (RDS) tarafından finanse edildi.

1. Streptolizin O Saflaştırılması (SLO) <ol><li> 0.5 L LB et suyu içine plazmid pBADgIII-SLOhis 9 içeren BL21 GOLD hücre, 20 ml gecelik kültürü aşılamak ve 500 ul 50 mg / ml ampisilin ilave edin. 37 ° C&#39;de 225 rpm&#39;de kültür çalkalanır OD 600 kadar = 0.6, genelde 1.5 saat ~. 10,000 5 dk xg az 1 ml bakteri (T 0 kabul) santrifüjleyin, 140 ul 1x SDS numune tamponu / 1 OD pelet çözülür ve protein saflık analizi için kesme DNA sonikasyon. </li><li> Kültür için 5 ml% 20 arabinoz ilavesi ile bakterilerin neden, 3 saat boyunca oda sıcaklığında 225 rpm de çalkalanır. , Bakteri 1 ml santrifüj toplayın ve yukarıda belirtildiği gibi saflık analizi için T 3 bir zaman noktası için 1 x SDS numune tamponu içinde çözülür. </li><li> 500 ml santrifüj Şişede kalan bakteriler toplayın, 4 ° C (8,500 rpm Sorvall GS-3 rotor) az 12 dakika boyunca 12.000 xg&#39;de döndürün. -80 Süpernatant, mağaza pelet Durusu gerekirse uzun ° C gecede ya. </li><li> Fr süspanse10 ml buz üzerinde ozen topak parçalayıcı / yıkama tampon (50 mM NaH 2 PO 4, 300 mM NaCl, 10 mM imidazol, pH 8.0) 400 ul% 25 oranında Triton X-100, 100 ul 100 mg / ml lizozim, 50 ile desteklenmiş ul 200 mM phenylmethylsulfonyl florid (PMSF). 50 ml Oak Ridge tüp yeniden süspanse pelet aktarın. </li><li> 30 sn aralıklarla buz üzerinde 30 saniye boyunca 5 kez lizat sonikasyon. Spin 4 ° C (18.000 rpm Sorvall SS-34 rotor) az 20 dakika boyunca 39.000 xg&#39;de oak ridge tüp lizat sonicated. </li><li> Lizat iplik iken, Lyse / 4 az 5 dakika boyunca 1.200 rpm&#39;de tampon ve santrifüj yıkayın ° 10 ml 1 ml Ni-NTA agaroz yıkayın C. (Tüm diğer yıkar / elutions bu koşullarda santrifüj kullanın). Yıkayın aspire. </li><li> Adım 1.5 Ni-NTA agaroz bakteriyel süpernatant ekleyin, 4 az 2,5 saat süreyle hafifçe sallayın ° C. Süpernatant toplamak için Spin. 10 μ 4x SDS numune tamponu ile süpernatant 30 ul birleştirin ve saflık analizi için kaydedin. Tampon Lyse / yıkayın ve üzerine boncuk 4 kez yıkayınTris / tuz tamponu (50 mM Tris, 300 mM NaCl, pH 8.0) içinde CE. </li><li> , Boncuklar ile Elüsyon, 1 ml tampon maddesi (Tris / tuz tamponu içinde 250 mM imidazol) ve 5 ul 1 M ditiotreitol (DTT) ilave 10 dakika boyunca buz üzerinde kuluçkaya, eğirme ve üstte kalan sıvı toplama ile 3 kez Zehir. SLO bir çok redoks-duyarlı bir protein olup, her zaman buz üzerinde tutulmalıdır. Bile kısa bir süre için, 37 ° C sıcaklığa getirilmiş ise bir kez azalır, protein hızla aktivitesi kaybedecektir. </li><li> 4 az 1 dakika boyunca 10.000 xg&#39;de elüsyon tampon, spin 500 ul polimiksin-konjuge agaroz yıkayın 500 ul ° C ve tekrar süspansiyon. Endotoksin tüketmek için, her bir yıkama için 200 ul boncuk ekleyin ve 30 dakika süre ile 4 ° C&#39;de çalkalanır. 1 4 dk ° C arasında ve süpernatan kaydetmek için 10,000 x g&#39;de Spin. SDS-PAGE analizi için 10 ul 4x SDS numune tamponu ile elüsyon her biri 30 ul birleştirin. </li><li> SDS-PAGE ile elutions saflığını test edin. Kaynama örnekleri,% 10 jel üzerinde 5 dakika ve yük 10 ul 95 ° C &#39;de jel analizi için kaydedilir. Ge LekeProtein görselleştirmek Coomassie ile l (Şekil 2A). SLO 69 kDa olduğunu. (Tipik verim 4 mg / ilk iki elutions için ml, ancak bakterinin ve plazmid kullanılan göre değişebilir) protein konsantrasyonu belirlemek için Bradford Testi gerçekleştirin. </li><li> Her elüsyonunun hemolitik aktivite (bkz. aşağıda) sınayın. Saflığı, konsantrasyon ve hemolitik aktivite tatmin edici Havuzu elutions. Tek kullanımlık alikotları (tipik olarak 5-10 ul) tablet SLO, -80 kuru buz ve mağaza ° C üzerinde dondurmak </li></ol> 2. Hemolitik Assay <ol><li> RBC deney tamponu (% 0.3 bovin serum albümini (BSA), 2 mM CaCl2, 10 mM Hepes, pH 7.4), 5 dakika boyunca 1,200 rpm&#39;de döndürme içinde koyun kırmızı kan hücrelerinin (eritrositler) yıkayın ve% 2.5 eritrositlerde de içinde tekrar süspansiyon 10 ml RBC Testi tampon. </li><li> / Kuyu buz üzerinde 96 oyuklu V-alt plaka 10 ul tahlil tamponu RBC ekleyin. Seri çoğaltmak her elüsyon seyreltin. Tipik seyreltme aralığı 1:1,000 ile 1:512,000 vardır. 10 ile hiçbir toksin ile 3 kuyu ve 3 kuyu dahilul% 2 Triton sırasıyla minimum ve maksimum kuyu olarak X-100,. </li><li> 37 plaka ve inkübe Kapak ° C 30 dk. 5 dakika boyunca 1.200 rpm&#39;de santrifüj. Düz dipli 96 plaka süpernatant 70 ul aktarın. A 405 okuyun. Bir birim, eritrositlerde% 50 lizis için gereken toksin seyreltilmesidir. Toksin aktivitesi 1 birim * dilüsyon factor/0.01 ml&#39;dir. </li></ol> 3. Hücre Parçalayıcı Assay <ol><li> Hasat hücreleri, sayım, spin. 2x10 &#39;de yeniden süspanse edin tampon içinde 6 / ml R / B (2 mM CaCl2 içeren RPMI,% 0.5 BSA) ve 20 ug / ml propidium iodide. Bir 96-V-alt plaka 100 ul hücre ekleyin. </li><li> Seri hücrelerine 100 ul toksin veya 100 ul tampon R / B ekleyebilir, tampon R / B nihai konsantrasyonu 2x SLO sulandırmak. Inkübe 5 dakika 37 ° C U / ml olarak 2,000 ila 31.25 U / ml &#39;ye Tipik nihai konsantrasyonlar aralığı. </li><li> Akış sitometresinde çalıştırın ve fikoeritrin (PE) için filtreler ile veri toplamak. Bir tek günlük vardiya geçici permeabilize cel temsills 3 günlük vardiya ölü hücreleri 4. gösterir iken. Aşağıdaki gibi, deneysel (% PI yüksek exp) den kontrol ölü hücrelerin yüzdesi (% PI yüksek ctl) çıkarılarak hücrelerin belirli lizis hesaplayın: Belirli lizis = (% PI yüksek exp -% PI yüksek ctl) / (100 -% PI yüksek ctl) * 100 </li></ol> 4. Kültür Yemekleri Hücreler Toksin Teslim mikropipet <ol><li> Bir kollajen kaplı cam alt 35 mm çanak deneyde, plaka 2x10 5 makrofajlar öncesinde bir gün. </li><li> Mikroskop ve mikroenjektör açın. Isıtılmış sahnede zaman 37 ° C&#39;ye kadar ısınmasını bekleyin Mikroskop seçim genellikle mevcut yerel ne bağlıdır. Mikroskop için 37 yemekler arasında bir ısıtma aşaması yeteneğine sahip bir ters evre ihtiyacı ° C, seçilmiş boya, ve fiziksel olarak mikroenjektör bağlamak için alan için uygun bir uyarılma / emisyon filtre küp. Bir Bertrand objektifmikroenjeksiyon için yararlı, ancak gerekli değildir. Mikroskop sürüş bilgisayar veri toplamak ve depolamak için yeterli bellek gerekiyor. </li><li> 37 boya ile 30 dakika için etiket hücreleri ° C. Tahlil bağlı olarak, etiketleme 5 ul Fura2 1 ml tam ortam içinde PM 1 ml PBS veya 2 ul içinde kalsein AM ile yapılabilir. Fura2 için, uyarılma / emisyon 340/510 nm ve 380/510 nm&#39;de için toplanmış, ve 340/380 sinyal oranının kalsiyum akısı belirler. Etidyum homodimer 525/620 nm ve APC 650/660 nm iken kalsein için, uyarma / emisyonu 495/515 nm. Diğer etiketler de seçilebilir. </li><li> 1 ml RPMI PBS ve yer ile hücreleri yıkayın 2 mM CaCl2 ile desteklenmiş. Mikroskop üzerine monte edin. </li><li> 4 ° C için 20,000 xg 10 dak toksin ve dekstran su ve santrifüj sulandırınız Tipik olarak, 1 ul SLO ve 4 ul 10 mg / ml dekstran-555 6 ul su içinde seyreltilir. Dekstran veya başka bir floresan sıvı faz molekülü Femto-ucu tıkalı olmadığını doğrulamak için kullanılan ve inje edilircts istediğiniz gibi. </li><li> Bir Microloader kullanarak seyreltilmiş toksin 0.07 ul arkadan Femto-ucu yerleştirin. </li><li> Mikroenjektör üzerine Femto-ucu yerleştirin. Uç tüm yönlerde hareket için oda hücreleri üzerinde merkezi olarak oturacak şekilde enjektör açısı ayarlayın. Z limiti temizleyin. Enjeksiyon ayarları 20 psi arka basıncı 120 psi az 0,5 sn enjekte edilmelidir. Bu orta girene kadar bahşiş indirin. </li><li> Bertrand lens merkezi ucu kullanma ve yakın hücreleri indirilir gibi ucu izleyin. Sonra odak kaybetmek normal optik geri dönün. Iğne gölge alanına anlaşılması gerekir. Yukarıda hücreler Odak ve odak kadar iğne indirin. Hücrelerin tekrar odaklanın ve dikkatli bir hücre bitişik iğne getir. Enjeksiyon için z limiti ayarlayın. İstediğiniz pozisyona ucu hareket görüntüleme başlasın, istenilen zaman noktasında toksin serbest bırakmak enjekte. Iğne kaldırın, hücreler yeni bir bölgeye taşımak ve enjekte. Istenmeyen önlemek için ev konumuna iğne Taşıiğne toksin kaçağı. </li></ol>

<ol>
	<li>Walev, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delivery+of+proteins+into+living+cells+by+reversible+membrane+permeabilization+with+streptolysin-O.">Delivery of proteins into living cells by reversible membrane permeabilization with streptolysin-O.</a> Proc. Natl. Acad. Sci. U.S.A. 98, 3185-3190 (2001).</li><li>Walev, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potassium+regulates+IL-1+beta+processing+via+calcium-independent+phospholipase+A2.">Potassium regulates IL-1 beta processing via calcium-independent phospholipase A2.</a> J. Immunol. 164, 5120-5124 (2000).</li><li>Scolding, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vesicular+removal+by+oligodendrocytes+of+membrane+attack+complexes+formed+by+activated+complement.">Vesicular removal by oligodendrocytes of membrane attack complexes formed by activated complement.</a> Nature. 339, 620-622 (1989).</li><li>Keyel, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Streptolysin+O+clearance+through+sequestration+into+blebs+that+bud+passively+from+the+plasma+membrane.">Streptolysin O clearance through sequestration into blebs that bud passively from the plasma membrane.</a> J. Cell. Sci. 124, 2414-2423 (2011).</li><li>MacKenzie, 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+secretion+of+interleukin-1beta+by+microvesicle+shedding.">Rapid secretion of interleukin-1beta by microvesicle shedding.</a> Immunity. 15, 825-835 (2001).</li><li>Qu, Y., Franchi, L., Nunez, G., Dubyak, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonclassical+IL-1+beta+secretion+stimulated+by+P2X7+receptors+is+dependent+on+inflammasome+activation+and+correlated+with+exosome+release+in+murine+macrophages.">Nonclassical IL-1 beta secretion stimulated by P2X7 receptors is dependent on inflammasome activation and correlated with exosome release in murine macrophages.</a> J. Immunol. 179, 1913-1925 (2007).</li><li>Andrei, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phospholipases+C+and+A2+control+lysosome-mediated+IL-1+beta+secretion:+Implications+for+inflammatory+processes.">Phospholipases C and A2 control lysosome-mediated IL-1 beta secretion: Implications for inflammatory processes.</a> Proc. Natl. Acad. Sci. U.S.A. 101, 9745-9750 (2004).</li><li>Franchi, L., Eigenbrod, T., Munoz-Planillo, R., Nunez, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+inflammasome:+a+caspase-1-activation+platform+that+regulates+immune+responses+and+disease+pathogenesis.">The inflammasome: a caspase-1-activation platform that regulates immune responses and disease pathogenesis.</a> Nat. Immunol. 10, 241-247 (2009).</li><li>Magassa, N., Chandrasekaran, S., Caparon, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Streptococcus+pyogenes+cytolysin-mediated+translocation+does+not+require+pore+formation+by+streptolysin+O.">Streptococcus pyogenes cytolysin-mediated translocation does not require pore formation by streptolysin O.</a> EMBO Rep. 11, 400-405 (2010).</li><li>Pinkney, M., Beachey, E., Kehoe, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+thiol-activated+toxin+streptolysin+O+does+not+require+a+thiol+group+for+cytolytic+activity.">The thiol-activated toxin streptolysin O does not require a thiol group for cytolytic activity.</a> Infect. Immun. 57, 2553-2558 (1989).</li><li>Watkins, S. C., Salter, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+connectivity+between+immune+cells+mediated+by+tunneling+nanotubules.">Functional connectivity between immune cells mediated by tunneling nanotubules.</a> Immunity. 23, 309-318 (2005).</li><li>McNeil, P. L., Vogel, S. S., Miyake, K., Terasaki, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patching+plasma+membrane+disruptions+with+cytoplasmic+membrane.">Patching plasma membrane disruptions with cytoplasmic membrane.</a> J. Cell. Sci. 113, 1891-1902 (2000).</li><li>Shannon, J. G., Ross, C. L., Koehler, T. M., Rest, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+anthrolysin+O,+the+Bacillus+anthracis+cholesterol-dependent+cytolysin.">Characterization of anthrolysin O, the Bacillus anthracis cholesterol-dependent cytolysin.</a> Infect. Immun. 71, 3183-3189 (2003).</li></ol>

Çıkar çatışması ilan etti.

Teknikleri bakteriyel toksinler bağışıklık hücrelerinin yanıtların incelenmesine olanak burada açıklanan. En kritik adım toksin kullanım ve dozaj olduğunu. Toksin aktivitesi hatta kırılganlık dolayı aynı hazırlanması farklı alikotları arasında, son derece değişken olabilir. Bu ya bir referans hücre hattı veya RBCs karşı toksin her kısım test veya toksin gradyanlar kullanarak gerektirir. Toksin gradyanlar gibi mikropipet tarafından teslim, gerçek zamanlı olarak uyulması gereken toksin k...

<table border="1"><tbody><tr><td> Reaktif Adı </td><td> Şirket </td><td> Katalog numarası </td><td> Yorumlar (isteğe bağlı) </td></tr><tr><td> Ni-NTA agaroz </td><td> Qiagen </td><td> 30210 </td><td></td></tr><tr><td> polimiksin-agaroz </td><td> Sigma </td><td> P1411-5ML </td><td></td></tr><tr><td> Zeba desalt Spin col </td><td> Balıkçı </td><td> PI-89891 </td><td></td></tr><tr><td> koyun RBCs </td><td> Balıkçı </td><td> 50-415-688 </td><td></td></tr><tr><td> pBADgIII-SLO </td><td> N / A </td><td> N / A </td><td> ref 9&#39;a bakınız </td></tr><tr><td> Cy5 monoreactive boya </td><td> GE Healthcare </td><td> PA25001 </td><td></td></tr><tr><td> Fura2-AM </td><td> Yaşam Teknolojileri </td><td> F1221 </td><td></td></tr><tr><td> Calcein AM / Ethidium homodimer </td><td> Yaşam Teknolojileri </td><td> L3224 </td><td></td></tr><tr><td> Anti-CD11c-APC </td><td> BD Biosciences </td><td> 550261 </td><td></td></tr><tr><td> kollajen kaplı cam alt tabak </td><td> Mattek </td><td> P35GCol-1.5-10-C </td><td></td></tr><tr><td> Femto-ucu II </td><td> Balıkçı </td><td> E5242957000 </td><td></td></tr><tr><td> Microloader </td><td> Balıkçı </td><td> E5242956003 </td><td></td></tr><tr><td> dekstran Alexa 555 </td><td> Yaşam Teknolojileri </td><td> D34679 </td><td></td></tr><tr><td> InjectMan NI 2 </td><td> Eppendorf </td><td> 920000029 </td><td></td></tr><tr><td> FemtoJet </td><td> Eppendorf </td><td> 5247 000.013 </td><td></td></tr><tr><td></td><td></td><td></td><td> Belirli reaktifler ve equipm Tablo 1. Liste ve kaynakent gerekli. Şirket ve katalog numarası ile birlikte bu protokolde kullanılan özel ekipman ve reaktifler, listelenir. </td></tr><tr><td></td><td></td><td></td><td><table border="1"><tbody><tr><td> Tampon </td><td> Kompozisyon </td><td> İkinci Adım </td></tr><tr><td> Yıkama / Lyse </td><td> 50 mM NaH 2 PO 4 300 mM NaCl 10 mM imidazol, pH 8.0 </td><td> 1.4 </td></tr><tr><td> Tris / tuz </td><td> 50 mM Tris, pH 8.0 300 mM NaCl </td><td> 1.7 </td></tr><tr><td> Seyreltme Tampon </td><td> 50 mM Tris, pH 8.0 300 mM NaCl 250 mM imidazol </td><td> 1.8 </td></tr><tr><td> RBC deney tamponu </td><td> % 0.3 BSA 2 mM CaCl2 10 mM HEPES, pH 7.4 </td><td> 2.1 </td></tr><tr><td> tampon R / B </td><td> RPMI hücre kültür ortamı 2 mM CaCl2 % 0.5 BSA </td><td&gt; 3.1 </td></tr></tbody></table></td></tr><tr><td></td><td></td><td></td><td> Bu protokolde kullanılan tamponların Tablo 2. Listesi. Ikinci tamponlar, bileşimlerine ve bu protokol kullanılmıştır girdiği ilk adım listelenmiştir. </td></tr></tbody></table>

visualization of bacterial toxin induced responses using live cell fluorescence microscopy

Bakteriyel toksinler hücresel içeriği ve dış ortamdan malzemelerin akını sızıntı izin gözenekleri oluşturan, zarlarında kolesterol bağlamak. Hücre ya aktif zarı tamir işlemleri gerektiren bu hakaret, kurtarmak, ya da başka bir toksine maruz kalma ve hücre tip 1 miktarına bağlı olarak ölebilir. Buna ek olarak, bu toksinlerin pro-inflamatuvar sitokinlerin 2 bir dizi üretmek makrofajlar dahil immün hücrelerin aktivasyonu yoluyla enfekte barındıran güçlü inflamatuar yanıtı indükler. Pek çok Gram pozitif bakteriler, büyük ölçüde karakterize olmamış mekanizmalar yoluyla virülans katkı gösterilmiştir kolesterol bağlayıcı toksinler üretirler. Bu toksinlere maruz hücrelerin plazma membranında Morfolojik değişiklikler intrinsik hücresel savunma düşündüren, ekstrasellüler boşluğa döken olabilir kolesterol bakımından zengin yüzey çıkıntıları, onların haciz dahilmekanizması 3,4. Bu işlem, metabolik etkinlik yokluğunda tüm hücrelerde meydana gelir, ve kimyasal tespit sonra 4 EM kullanılarak görüntülenebilir. Böyle toksine maruz kalma yanıt olarak inflamasyon aracılık makrofaj gibi immün hücrelerde indüklenen membran veziküller IL-1 ailesi sitokinler içermesi önerilmektedir ve toksin atma ve bu pro-inflamatuar sitokinler 5,6,7 yaymak için hem de sorumlu olabilir. Hem 8 kaspaz-1 bağımlı süreçlerin gibi IL-1β salınımı ve hücre ölümü belirli bir türü arasında bir bağlantı, adlandırdığı pyroptosis ileri sürülmüştür. Membran vezikül toksin bağlayıcı, dökülme, sitokin salınımı, ve potansiyel olarak hücre ölümü içeren bu makrofaj yanıtı, karmaşıklığı çözmek için, biz de dahil olmak üzere, toksin-hücre etkileşimleri gerçek zamanlı görselleştirme için izin etiketleme teknikleri ve floresans mikroskobu yöntemleri geliştirmişlerdir fonksiyon bozukluğu ve ölüm ölçümleri (Şekil 1). Kullanmakcanlı hücre görüntüleme diğer teknikleri sınırlamaları nedeniyle gereklidir. Flow sitometri bireysel hücrelerin yüksek çözünürlüklü, gerçek zamanlı görselleştirme sunmaz ise Biyokimyasal yaklaşımlar, bireysel hücrelerin meydana etkilerini çözemez. Burada açıklanan yöntemlerle hücrelerde kompleks fenotip değişiklikleri içeren başka bir uyarıya bağlı yanıt kinetik analizi için uygulanabilir.

Tipik olarak 10 7 -10 8 U / ml SLO 4 mg / ml &#39;lik bir protein konsantrasyonuna ile elde edilebilir. Hücre parçalama için gerekli toksin miktarı hücre türüne göre değişir, ancak genellikle 125-500 U / ml SLO (Şekil 2B) olduğunu. Diğerleri (özellikle T hücre hatları) daha duyarlı olsa makrofajlar gibi Hücre tipleri (4000 U / ml) daha dirençli olabilir. Bu duyarlılık, ticari olarak temin SLO karşılık gelir. Toksin aktivitesi toksin her parti veya çözülme...

Watch this Scientific Journal Video about Visualization of Bacterial Toxin Induced Responses Using Live Cell Fluorescence Microscopy at JoVE.com

Visualization of Bacterial Toxin Induced Responses Using Live Cell Fluorescence Microscopy

Rekombinant gelen kolesterol bağlayıcı toksin Streptolizin O arındırıcı Yöntemleri<em&gt; E. coli</emÖkaryotik hücrelerin canlı bağlanabilen toksininin&gt; ve görüntüleme tarif edilmektedir. Toksin Lokalize teslimat toksin biyoloji romanı yönlerini açığa hedeflenen hücrelerde hızlı ve karmaşık değişikliklere sebep olur.

Canlı Hücre Floresan Mikroskopi kullanma Bakteriyel Toksin İsteyerek Yanıtların Görselleştirme

Bacterial toxins bind to cholesterol in membranes, forming pores that allow for leakage of cellular contents and influx of materials from the external ...

visualization-bacterial-toxin-induced-responses-using-live-cell

Research

JoVE Journal

Immunology and Infection

11.7K Görüntüleme.  University of Pittsburgh School of Medicine. Rekombinant gelen kolesterol bağlayıcı toksin Streptolizin O arındırıcı Yöntemleri E. coli ve görüntüleme tarif edilmektedir. Toksin Lokalize teslimat toksin biyoloji romanı yönlerini açığa hedeflenen hücrelerde hızlı ve karmaşık değişikliklere sebep olur.

Video: Visualization of Bacterial Toxin Induced Responses Using Live Cell Fluorescence Microscopy

Visualizing Cell-to-cell Transfer of HIV using Fluorescent Clones of HIV and Live Confocal Microscopy

By fusing the green fluorescent protein to their favorite proteins, biologists now have the ability to study living complex cellular processes using fluorescence video microscopy. To track the movements of the human immunodeficiency virus core protein during cell-to-cell transmission of human immunodeficiency virus, we have GFP-tagged the Gag protein in the context of an infectious molecular clone of HIV, called HIV Gag-iGFP. We study this viral clone using video confocal microscopy. In the following visualized experiment, we transfect a human T cell line with HIV Gag-iGFP, and we use fluorescently labeled uninfected CD4+ T cells to serve as target cells for the virus. Using the different fluorescent labels we can readily follow viral production and transport across intercellular structures called virological synapses. Simple gas permeable imaging chambers allow us to observe synapses with live confocal microscopy from minutes to days. These approaches can be used to track viral proteins as they move in from one cell to the next.

This visualized experiment is a guide for utilizing a fluorescent molecular clone of HIV for live confocal imaging experiments.

HIV ve Live Konfokal Mikroskop Floresan Klonlar kullanılarak HIV görselleştirme Hücre-hücre Transferi

By fusing the green fluorescent protein to their favorite proteins, biologists now have the ability to study living complex cellular processes using ...

İmmünoloji ve Enfeksiyon

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.

Tüm Yaprak Görüntüleme kullanarak Bakteriyel Hücreler Live Stoma Tepki Değerlendirilmesi

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

Live Cell Imaging of Bacillus subtilis and Streptococcus pneumoniae using Automated Time-lapse Microscopy

During the last few years scientists became increasingly aware that average data obtained from microbial population based experiments are not representative of the behavior, status or phenotype of single cells. Due to this new insight the number of single cell studies rises continuously (for recent reviews see 1,2,3). However, many of the single cell techniques applied do not allow monitoring the development and behavior of one specific single cell in time (e.g. flow cytometry or standard microscopy).
Here, we provide a detailed description of a microscopy method used in several recent studies 4, 5, 6, 7, which allows following and recording (fluorescence of) individual bacterial cells of Bacillus subtilis and Streptococcus pneumoniae through growth and division for many generations. The resulting movies can be used to construct phylogenetic lineage trees by tracing back the history of a single cell within a population that originated from one common ancestor. This time-lapse fluorescence microscopy method cannot only be used to investigate growth, division and differentiation of individual cells, but also to analyze the effect of cell history and ancestry on specific cellular behavior. Furthermore, time-lapse microscopy is ideally suited to examine gene expression dynamics and protein localization during the bacterial cell cycle. The method explains how to prepare the bacterial cells and construct the microscope slide to enable the outgrowth of single cells into a microcolony. In short, single cells are spotted on a semi-solid surface consisting of growth medium supplemented with agarose on which they grow and divide under a fluorescence microscope within a temperature controlled environmental chamber. Images are captured at specific intervals and are later analyzed using the open source software ImageJ.

Live Cell Imaging of Bacillus subtilis and Streptococcus pneumoniae using Automated Time-lapse Microscopy

This protocol provides a step-by-step procedure to monitor single cell behavior of different bacteria in time using automated fluorescence time-lapse microscopy. Furthermore, we provide guidelines how to analyze the microscopy images.

Canlı Hücre Görüntüleme Bacillus subtilis Ve Streptococcus pneumoniae Otomatik Zaman atlamalı Mikroskopi

During the last few years scientists became increasingly aware that average data obtained from microbial population based experiments are not ...

Single-cell Analysis of Bacillus subtilis Biofilms Using Fluorescence Microscopy and Flow Cytometry

Biofilm formation is a general attribute to almost all bacteria 1-6. When bacteria form biofilms, cells are encased in extracellular matrix that is mostly constituted by proteins and exopolysaccharides, among other factors 7-10. The microbial community encased within the biofilm often shows the differentiation of distinct subpopulation of specialized cells 11-17. These subpopulations coexist and often show spatial and temporal organization within the biofilm 18-21.
Biofilm formation in the model organism Bacillus subtilis requires the differentiation of distinct subpopulations of specialized cells. Among them, the subpopulation of matrix producers, responsible to produce and secrete the extracellular matrix of the biofilm is essential for biofilm formation 11,19. Hence, differentiation of matrix producers is a hallmark of biofilm formation in B. subtilis.
We have used fluorescent reporters to visualize and quantify the subpopulation of matrix producers in biofilms of B. subtilis 15,19,22-24. Concretely, we have observed that the subpopulation of matrix producers differentiates in response to the presence of self-produced extracellular signal surfactin 25. Interestingly, surfactin is produced by a subpopulation of specialized cells different from the subpopulation of matrix producers 15.
We have detailed in this report the technical approach necessary to visualize and quantify the subpopulation of matrix producers and surfactin producers within the biofilms of B. subtilis. To do this, fluorescent reporters of genes required for matrix production and surfactin production are inserted into the chromosome of B. subtilis. Reporters are expressed only in a subpopulation of specialized cells. Then, the subpopulations can be monitored using fluorescence microscopy and flow cytometry (See Fig 1).
The fact that different subpopulations of specialized cells coexist within multicellular communities of bacteria gives us a different perspective about the regulation of gene expression in prokaryotes. This protocol addresses this phenomenon experimentally and it can be easily adapted to any other working model, to elucidate the molecular mechanisms underlying phenotypic heterogeneity within a microbial community.

Single-cell Analysis of Bacillus subtilis Biofilms Using Fluorescence Microscopy and Flow Cytometry

Microbial biofilms are generally constituted by distinct subpopulations of specialized cells. Single-cell analysis of these subpopulations requires the use of fluorescent reporters. Here we describe a protocol to visualize and monitor several subpopulationswithin B. subtilis biofilms using fluorescence microscopy and flow cytometry.

Tek hücreli Analizi Bacillus subtilis</emFloresan Mikroskobu ve Akım Sitometri Kullanma> Biyofilmler

Biofilm formation is a general attribute to almost all bacteria 1-6. When bacteria form biofilms, cells are encased in extracellular matrix that is mostly ...

Live-cell Video Microscopy of Fungal Pathogen Phagocytosis

Phagocytic clearance of fungal pathogens, and microorganisms more generally, may be considered to consist of four distinct stages: (i) migration of phagocytes to the site where pathogens are located; (ii) recognition of pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs); (iii) engulfment of microorganisms bound to the phagocyte cell membrane, and (iv) processing of engulfed cells within maturing phagosomes and digestion of the ingested particle. Studies that assess phagocytosis in its entirety are informative1, 2, 3, 4, 5 but are limited in that they do not normally break the process down into migration, engulfment and phagosome maturation, which may be affected differentially. Furthermore, such studies assess uptake as a single event, rather than as a continuous dynamic process. We have recently developed advanced live-cell imaging technologies, and have combined these with genetic functional analysis of both pathogen and host cells to create a cross-disciplinary platform for the analysis of innate immune cell function and fungal pathogenesis. These studies have revealed novel aspects of phagocytosis that could only be observed using systematic temporal analysis of the molecular and cellular interactions between human phagocytes and fungal pathogens and infectious microorganisms more generally. For example, we have begun to define the following: (a) the components of the cell surface required for each stage of the process of recognition, engulfment and killing of fungal cells1, 6, 7, 8; (b) how surface geometry influences the efficiency of macrophage uptake and killing of yeast and hyphal cells7; and (c) how engulfment leads to alteration of the cell cycle and behavior of macrophages 9, 10.
In contrast to single time point snapshots, live-cell video microscopy enables a wide variety of host cells and pathogens to be studied as continuous sequences over lengthy time periods, providing spatial and temporal information on a broad range of dynamic processes, including cell migration, replication and vesicular trafficking. Here we describe in detail how to prepare host and fungal cells, and to conduct the video microscopy experiments. These methods can provide a user-guide for future studies with other phagocytes and microorganisms.

We describe methods for live-cell video microscopy of Candida albicans phagocytosis by macrophages. These methods enable stage-specific analysis of macrophage migration, recognition, engulfment and phagosome maturation and reveal novel aspects of phagocytosis.

Fungal Patojen Fagositoz Canlı hücre video Mikroskopi

Phagocytic clearance of fungal pathogens, and microorganisms more generally, may be considered to consist of four distinct stages: (i) migration of ...

Visualizing Protein-DNA Interactions in Live Bacterial Cells Using Photoactivated Single-molecule Tracking

Protein-DNA interactions are at the heart of many fundamental cellular processes. For example, DNA replication, transcription, repair, and chromosome organization are governed by DNA-binding proteins that recognize specific DNA structures or sequences. In vitro experiments have helped to generate detailed models for the function of many types of DNA-binding proteins, yet, the exact mechanisms of these processes and their organization in the complex environment of the living cell remain far less understood. We recently introduced a method for quantifying DNA-repair activities in live Escherichia coli cells using Photoactivated Localization Microscopy (PALM) combined with single-molecule tracking. Our general approach identifies individual DNA-binding events by the change in the mobility of a single protein upon association with the chromosome. The fraction of bound molecules provides a direct quantitative measure for the protein activity and abundance of substrates or binding sites at the single-cell level. Here, we describe the concept of the method and demonstrate sample preparation, data acquisition, and data analysis procedures.

Photoactivated localization microscopy (PALM) combined with single-molecule tracking allows direct observation and quantification of protein-DNA interactions in live Escherichia coli cells.

Fotoaktive Tek molekül Takip Kullanma Canlı Bakteriyel Hücrelerde Protein-DNA Etkileşimleri görselleştirme

Protein-DNA interactions are at the heart of many fundamental cellular processes. For example, DNA replication, transcription, repair, and chromosome ...

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence factors, which can subvert and manipulate key host functions. The study of host/pathogen interactions is therefore extremely important to understand bacterial infections and develop alternative strategies to counter infectious diseases. This approach however, requires the development of new high-throughput assays for the unbiased, automated identification and characterization of bacterial virulence determinants. Here, we describe a method for the generation of a GFP-tagged mutant library by transposon mutagenesis and the development of high-content screening approaches for the simultaneous identification of multiple transposon-associated phenotypes. Our working model is the intracellular bacterial pathogen Coxiellaburnetii, the etiological agent of the zoonosis Q fever, which is associated with severe outbreaks with a consequent health and economic burden. The obligate intracellular nature of this pathogen has, until recently, severely hampered the identification of bacterial factors involved in host pathogen interactions, making of Coxiella the ideal model for the implementation of high-throughput/high-content approaches.

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Coxiella burnetii is an obligate intracellular Gram-negative bacterium responsible for the zoonotic disease Q fever. Here we describe methods for the generation of Coxiella fluorescent transposon mutants as well as the automated identification and analysis of the resulting internalization, replication and cytotoxic phenotypes.

Üretim ve Çok fenotipik Yüksek içerik Eleme<em&gt; Coxiella burnetii</em&gt; Transposon Mutantlar

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence ...

Measuring Physiological Responses of Drosophila Sensory Neurons to Lipid Pheromones Using Live Calcium Imaging

Unlike mammals, insects such as Drosophila have multiple taste organs. The chemosensory neurons on the legs, proboscis, wings and ovipositor of Drosophila express gustatory receptors1,2, ion channels3-6, and ionotropic receptors7 that are involved in the detection of volatile and non-volatile sensory cues. These neurons directly contact tastants such as food, noxious substances and pheromones and therefore influence many complex behaviors such as feeding, egg-laying and mating. Electrode recordings and calcium imaging have been widely used in insects to quantify the neuronal responses evoked by these tastants. However, electrophysiology requires specialized equipment and obtaining measurements from a single taste sensillum can be technically challenging depending on the cell-type, size, and position. In addition, single neuron resolution in Drosophila can be difficult to achieve since taste sensilla house more than one type of chemosensory neuron. The live calcium imaging method described here allows responses of single gustatory neurons in live flies to be measured. This method is especially suitable for imaging neuronal responses to lipid pheromones and other ligand types that have low solubility in water-based solvents.

Measuring Physiological Responses of Drosophila Sensory Neurons to Lipid Pheromones Using Live Calcium Imaging

The forelegs and proboscis of Drosophila contain a rich repertoire of gustatory sensory neurons. Here, we present a method using calcium imaging to measure physiological responses from sensory neurons in the foreleg and proboscis of live flies upon exogenous application of a gustatory pheromone.

Fizyolojik Yanıtları Ölçüm<em&gt; Drosophila</em&gt; Canlı Kalsiyum Görüntüleme kullanma Lipit Feromonlar Sensory Nöronlar

Unlike mammals, insects such as Drosophila have multiple taste organs. The chemosensory neurons on the legs, proboscis, wings and ovipositor of Drosophila ...

Quantification of Efferocytosis by Single-cell Fluorescence Microscopy

Studying the regulation of efferocytosis requires methods that are able to accurately quantify the uptake of apoptotic cells and to probe the signaling and cellular processes that control efferocytosis. This quantification can be difficult to perform as apoptotic cells are often efferocytosed piecemeal, thus necessitating methods which can accurately delineate between the efferocytosed portion of an apoptotic target versus residual unengulfed cellular fragments. The approach outlined herein utilizes dual-labeling approaches to accurately quantify the dynamics of efferocytosis and efferocytic capacity of efferocytes such as macrophages. The cytosol of the apoptotic cell is labeled with a cell-tracking dye to enable monitoring of all apoptotic cell-derived materials, while surface biotinylation of the apoptotic cell allows for differentiation between internalized and non-internalized apoptotic cell fractions. The efferocytic capacity of efferocytes is determined by taking fluorescent images of live or fixed cells and quantifying the amount of bound versus internalized targets, as differentiated by streptavidin staining. This approach offers several advantages over methods such as flow cytometry, namely the accurate delineation of non-efferocytosed versus efferocytosed apoptotic cell fractions, the ability to measure efferocytic dynamics by live-cell microscopy, and the capacity to perform studies of cellular signaling in cells expressing fluorescently-labeled transgenes. Combined, the methods outlined in this protocol serve as the basis for a flexible experimental approach that can be used to accurately quantify efferocytic activity and interrogate cellular signaling pathways active during efferocytosis.

Efferocytosis, the phagocytic removal of apoptotic cells, is required to maintain homeostasis and is facilitated by receptors and signaling pathways that allow for the recognition, engulfment, and internalization of apoptotic cells. Herein, we present a fluorescence microscopy protocol for the quantification of efferocytosis and the activity of efferocytic signaling pathways.

Efferocytosis tek hücreli floresans mikroskobu tarafından miktar

Studying the regulation of efferocytosis requires methods that are able to accurately quantify the uptake of apoptotic cells and to probe the signaling ...

Using a Bacterial Pathogen to Probe for Cellular and Organismic-level Host Responses

There are a variety of strategies bacterial pathogens employ to survive and proliferate once inside the eukaryotic cell. The so-called 'cytosolic' pathogens (Listeria monocytogenes, Shigella flexneri, Burkholderia pseudomallei, Francisella tularensis, and Rickettsia spp.) gain access to the infected cell cytosol by physically and enzymatically degrading the primary vacuolar membrane. Once in the cytosol, these pathogens both proliferate as well as generate sufficient mechanical forces to penetrate the plasma membrane of the host cell in order to infect new cells. Here, we show how this terminal step of the cellular infection cycle of L. monocytogenes (Lm) can be quantified by both colony-forming unit assays and flow cytometry and give examples of how both pathogen- and host-encoded factors impact this process. We also show a close correspondence of Lm infection dynamics of cultured cells infected in vitro and those of hepatic cells derived from mice infected in vivo. These function-based assays are relatively simple and can be readily scaled up for discovery-based high-throughput screens for modulators of eukaryotic cell function.

We describe both in vitro and in vivo infection assays that can be used to analyze the activities of host-encoding factors.