Preparation, Imaging, and Quantification of Bacterial Surface Motility Assays

Bacterial surface motility, such as swarming, is commonly examined in the laboratory using plate assays that necessitate specific concentrations of agar ...

University of Notre Dame

Xenorhabdus nematophila, the mutualistic bacterium of the nematode Steinernema carpocapsae, produces the R-type bacteriocin called xenorhabdicin, which is thought to confer a competitive advantage for growth in the insect host. We have identified a P2-like tail synthesis gene cluster (xnp1) that is required for xenorhabdicin production. The xnp1 genes were expressed constitutively during growth and were induced by mitomycin C. Deletion of either the sheath (xnpS1) or fiber (xnpH1) genes eliminated xenorhabdicin production. Production of R-type bacteriocins in a host organism had not been shown previously. We show that xenorhabdicin is produced in the hemocoel of insects infected with the wild type but not with the ΔxnpS1 deletion strain. Xenorhabdicin prepared from the wild-type strain killed the potential competitor Photorhabdus luminescens TT01. P. luminescens was eliminated during coculture with wild-type X. nematophila but not with the ΔxnpS1 strain. Furthermore, P. luminescens inhibited reproduction of S. carpocapsae in insect larvae, while coinjection with wild-type X. nematophila, but not the ΔxnpS1, strain restored normal reproduction, demonstrating that xenorhabdicin was required for killing P. luminescens and protecting the nematode partner. Xenorhabdicin killed X. nematophila from Steinernema anatoliense, demonstrating for the first time that it possesses intraspecies activity. In addition, activity was variable against diverse strains of Xenorhabdus and Photorhabdus and was not correlated with phylogenetic distance. These findings are discussed in the context of the role of xenorhabdicin in the life cycle of the mutualistic bacterium X. nematophila.

The xnp1 P2-like tail synthesis gene cluster encodes xenorhabdicin and is required for interspecies competition.

&#x7EBF;&#x866B;&#x4E0E;&#x76F8;&#x5173;&#x8054;&#x7684;&#x6606;&#x866B;&#x75C5;&#x539F;&#x7EC6;&#x83CC;&#x5C5E;&#x7684;&#x6210;&#x5458;&#x6606;&#x866B;&#x75C5;&#x539F;&#x7EBF;&#x866B;&#x3002;&#x7EBF;&#x866B;&#x7EC6;&#x83CC;&#x5BF9;&#x611F;&#x67D3;&#x5E76;&#x6740;&#x6B7B;&#x6606;&#x866B;&#xFF0C;&#x6606;&#x866B;&#x7684;&#x53D1;&#x75C5;&#x673A;&#x5236;&#x548C;&#x63D0;&#x4F9B;&#x8425;&#x517B;&#x5BF9;&#x7EBF;&#x866B;&#x4ECE;&#x6606;&#x866B;&#x6D3E;&#x751F;&#x7684;&#x6709;&#x6548;&#x517B;&#x5206;&#x7684;&#x7EC6;&#x83CC;&#x4F5C;&#x51FA;&#x8D21;&#x732E;&#x8FD9;&#x4E24;&#x4E2A;&#x4F19;&#x4F34;&#x3002;&#x7EBF;&#x866B;&#x4ECE;&#x63A0;&#x98DF;&#x8005;&#x3001; &#x8425;&#x517B;&#xFF0C;&#x83B7;&#x5F97;&#x548C;&#x5206;&#x6563;&#x7684;&#x673A;&#x5236;&#x63D0;&#x4F9B;&#x4E0E;&#x4FDD;&#x62A4;&#x7EC6;&#x83CC;&#x3002;&#x7EBF;&#x866B;&#x5171;&#x751F;&#x7EC6;&#x83CC;&#x5C5E;&#x7684;&#x6210;&#x5458;&#x8FD8;&#x8D5E;&#x540C;&#x7EBF;&#x866B;&#x6740;&#x6B7B;&#x6606;&#x866B;&#xFF0C;&#x548C;&#x8FD9;&#x4E24;&#x4E2A;&#x5C5E;&#x7684;&#x7EC6;&#x83CC;&#x901A;&#x8FC7;&#x72EC;&#x7279;&#x7684;&#x751F;&#x7406;&#x548C;&#x4EE3;&#x8C22;&#x673A;&#x5236;&#x7ED9;&#x4ED6;&#x4EEC;&#x4E0D;&#x540C;&#x7684;&#x7EBF;&#x866B;&#x4E3B;&#x673A;&#x63D0;&#x4F9B;&#x7C7B;&#x4F3C;&#x7684;&#x670D;&#x52A1;&#x3002;&#x6211;&#x4EEC;&#x5047;&#x5B9A;&#x8FD9;&#x4E9B;&#x5DEE;&#x5F02;&#x5C06;&#x4F1A;&#x53CD;&#x6620;&#x5728;&#x4ED6;&#x4EEC;&#x5404;&#x81EA;&#x7684;&#x57FA;&#x56E0;&#x7EC4;&#x3002;&#x82E5;&#x8981;&#x6D4B;&#x8BD5;&#x6B64;&#xFF0C;&#x6211;&#x4EEC;&#x5B8C;&#x6210;&#x57FA;&#x56E0;&#x6392;&#x5217;&#x7684;&#x55DC;&#x7EBF;&#x866B;&#x81F4;&#x75C5;&#x6746;&#x83CC; ATCC 19061 &#x548C;&#x6606;&#x866B;&#x75C5;&#x539F;&#x7EBF;&#x866B; bovienii SS-2004 &#x5E74;&#x3002;&#x5982;&#x6240;&#x6599;&#xFF0C;&#x8FD9;&#x4E24;&#x79CD;&#x6606;&#x866B;&#x75C5;&#x539F;&#x7EBF;&#x866B;&#x57FA;&#x56E0;&#x7EC4;&#x7F16;&#x7801;&#x8BB8;&#x591A; anti-insecticidal &#x7684;&#x5316;&#x5408;&#x7269;&#xFF0C;&#x4E0E;&#x4ED6;&#x4EEC;&#x7684;&#x6606;&#x866B;&#x75C5;&#x539F;&#x751F;&#x6D3B;&#x65B9;&#x5F0F;&#x76F8;&#x9002;&#x5E94;&#x3002;&#x5C3D;&#x7BA1;&#x5728;&#x751F;&#x6D3B;&#x65B9;&#x5F0F;&#x4E4B;&#x95F4;&#x5171;&#x751F;&#x7EC6;&#x83CC;&#x3001; &#x6606;&#x866B;&#x75C5;&#x539F;&#x7EBF;&#x866B;&#x3001; &#x866B;&#x5A92;&#xFF0C;&#x6BD4;&#x8F83;&#x5206;&#x6790;&#x7684;&#x76F8;&#x4F3C;&#x4E4B;&#x5904;&#x548C;&#x4F53;&#x80B2; asymbiotica &#x57FA;&#x56E0;&#x7EC4;&#x8868;&#x660E;&#x57FA;&#x56E0;&#x7EC4;&#x5206;&#x6B67;&#x3002;&#x8FD9;&#x4E9B;&#x7ED3;&#x679C;&#x8868;&#x660E;&#x6F14;&#x53D8;&#x5F62;&#x6210;&#x7684;&#x5171;&#x751F;&#x4E92;&#x52A8;&#x53EF;&#x4EE5;&#x6309;&#x7167;&#x4E0D;&#x540C;&#x7684;&#x9014;&#x5F84;&#x6765;&#x5B9E;&#x73B0;&#x7C7B;&#x4F3C;&#x7684;&#x7ED3;&#x675F;&#x70B9;&#x3002;

&#x6606;&#x866B;&#x75C5;&#x539F;&#x7EC6;&#x83CC; endosymbionts &#x5171;&#x751F;&#xFF1A; &#x6536;&#x655B;&#x7684;&#x751F;&#x6D3B;&#x65B9;&#x5F0F;&#xFF0C;&#x4ECE;&#x4E0D;&#x540C;&#x7684;&#x57FA;&#x56E0;&#x7EC4;&#x3002;

Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, with both partners contributing to insect pathogenesis and the bacteria providing nutrition to the nematode from available insect-derived nutrients. The nematode provides the bacteria with protection from predators, access to nutrients, and a mechanism of dispersal. Members of the bacterial genus Photorhabdus also associate with nematodes to kill insects, and both genera of bacteria provide similar services to their different nematode hosts through unique physiological and metabolic mechanisms. We posited that these differences would be reflected in their respective genomes. To test this, we sequenced to completion the genomes of Xenorhabdus nematophila ATCC 19061 and Xenorhabdus bovienii SS-2004. As expected, both Xenorhabdus genomes encode many anti-insecticidal compounds, commensurate with their entomopathogenic lifestyle. Despite the similarities in lifestyle between Xenorhabdus and Photorhabdus bacteria, a comparative analysis of the Xenorhabdus, Photorhabdus luminescens, and P. asymbiotica genomes suggests genomic divergence. These findings indicate that evolutionary changes shaped by symbiotic interactions can follow different routes to achieve similar end points.

The entomopathogenic bacterial endosymbionts Xenorhabdus and Photorhabdus: convergent lifestyles from divergent genomes.

Les membres des Xenorhabdus genre sont des bact&#xE9;ries entomopathog&#xE8;nes qui s&#x26;#39;associent avec les n&#xE9;matodes. La paire de n&#xE9;matodes-bact&#xE9;ries infecte et tue les insectes, avec les deux partenaires contribuant &#xE0; la pathogen&#xE8;se des insectes et des bact&#xE9;ries fournir une nutrition au n&#xE9;matode &#xE0; partir d&#x26;#39;insectes disponibles d&#xE9;riv&#xE9;s nutriments. Le n&#xE9;matode fournit les bact&#xE9;ries avec protection contre les pr&#xE9;dateurs, l&#x26;#39;acc&#xE8;s aux &#xE9;l&#xE9;ments nutritifs, et un m&#xE9;canisme de dispersion. Les membres du genre bact&#xE9;rien Photorhabdus &#xE9;galement associ&#xE9; avec des n&#xE9;matodes pour tuer les insectes, et les deux genres de bact&#xE9;ries de fournir des services similaires &#xE0; leurs h&#xF4;tes des n&#xE9;matodes &#xE0; travers diff&#xE9;rents m&#xE9;canismes uniques physiologiques et m&#xE9;taboliques. Nous pos&#xE9; en principe que ces diff&#xE9;rences seraient prises en compte dans leurs g&#xE9;nomes respectifs. Pour tester cela, nous avons s&#xE9;quenc&#xE9; les g&#xE9;nomes de l&#x26;#39;ach&#xE8;vement de Xenorhabdus nematophila 19061 ATCC et Xenorhabdus bovienii SS-2004. Comme pr&#xE9;vu, les deux g&#xE9;nomes Xenorhabdus coder de nombreux anti-insecticides compos&#xE9;s, en rapport avec leur mode de vie entomopathog&#xE8;ne. Malgr&#xE9; les similitudes de style de vie entre Xenorhabdus et Photorhabdus bact&#xE9;ries, une analyse comparative des Xenorhabdus, Photorhabdus luminescens, et P. g&#xE9;nomes asymbiotica sugg&#xE8;re divergence g&#xE9;nomique. Ces r&#xE9;sultats indiquent que les changements &#xE9;volutifs fa&#xE7;onn&#xE9;s par les interactions symbiotiques peuvent suivre des voies diff&#xE9;rentes pour atteindre des points finaux similaires.

Les entomopathog&#xE8;nes bact&#xE9;riennes Xenorhabdus endosymbiontes et Photorhabdus: Style de vie convergent de g&#xE9;nomes divergents

Arten der Gattung sind Xenorhabdus Entomopathogenic Bakterien, die Nematoden zuordnen. Das Paar Fadenw&uuml;rmer-Bakterien infiziert und t&ouml;tet Insekten, mit beiden Partnern zu Insekt Pathogenese und die Bakterien, die die Ern&auml;hrung f&uuml;r die Fadenw&uuml;rmer aus verf&uuml;gbaren Insekt abgeleitete N&auml;hrstoffen beitragen. Die Fadenw&uuml;rmer bietet die Bakterien mit Schutz vor Raubtieren, Zugriff auf N&auml;hrstoffe und einen Mechanismus der Zerstreuung. Mitglieder der Gattung bakterielle Photorhabdus ordnen auch Nematoden, Insekten zu t&ouml;ten, und beide Gattungen von Bakterien bieten &auml;hnliche Dienste an ihre verschiedene Fadenw&uuml;rmer Hosts durch eindeutige physiologische und metabolische Mechanismen. Wir postuliert, dass diese Unterschiede in ihren jeweiligen Genome niederschlagen w&uuml;rde. Um dies zu testen, sequenziert wir bis zur Fertigstellung der Genome Xenorhabdus Nematophila ATCC 19061 und Xenorhabdus Bovienii SS-2004. Wie erwartet, codieren beide Genome Xenorhabdus viele anti-insecticidal Verbindungen, angemessen mit ihren Entomopathogenic Lebensstil. Trotz der &Auml;hnlichkeiten im Lebensstil zwischen Xenorhabdus und Photorhabdus Bakterien, eine vergleichende Analyse der Xenorhabdus, Photorhabdus und, und p. Asymbiotica Genome schl&auml;gt genomische Divergenz. Diese Befunde zeigen, dass evolution&auml;re Ver&auml;nderungen gepr&auml;gt durch Symbiotische Interaktionen verschiedene Routen um &auml;hnliche Endpunkte zu erreichen folgen k&ouml;nnen.

Die Entomopathogenic bakterielle Endosymbionts Xenorhabdus und Photorhabdus: konvergente Lebensstile aus unterschiedlichen Genomen.

I membri del genere Xenorhabdus sono batteri entomopatogeni che associano a nematodi. La coppia di nematode-batteri infetta e uccide gli insetti, con entrambi i partner che contribuiscono alla patogenesi degli insetti e i batteri fornire nutrizione per il nematode del disponibile nutrienti derivati da insetti. Il nematode fornisce i batteri con protezione da predatori, l&#39;accesso a sostanze nutritive e un meccanismo di dispersione. Membri del genere batterico Photorhabdus associano anche nematodi per uccidere gli insetti, e due generi di batteri forniscono servizi simili ai loro ospiti diversi nematodi attraverso meccanismi fisiologici e metabolici unici. Abbiamo postulato che queste differenze si rifletterebbero nei loro rispettivi genomi. Per eseguire questo test, abbiamo sequenziato per completamento i genomi di Xenorhabdus nematophila ATCC 19061 e Xenorhabdus bovienii SS-2004. Come previsto, entrambi genomi Xenorhabdus codificano molti composti anti-insecticidal, commisurati alla loro vita entomopatogeni. Nonostante le somiglianze nello stile di vita tra i batteri Xenorhabdus e Photorhabdus, un&#39;analisi comparativa dei Xenorhabdus, Photorhabdus luminescens, e p. asymbiotica genomes suggerisce genomic divergenza. Questi risultati indicano che cambiamenti evolutivi a forma di interazione simbiotiche possono seguire diverse vie per raggiungere i punti finali simili.

L&#39;entomopatogeni batteri endosimbionti Xenorhabdus e Photorhabdus: lifestyles convergenti da genomi divergenti.

&#x5C5E;Xenorhabdus&#x306E;&#x30E1;&#x30F3;&#x30D0;&#x30FC;&#x306F;&#x3001;&#x7DDA;&#x866B;&#x306B;&#x95A2;&#x9023;&#x4ED8;&#x3051;&#x308B;&#x6606;&#x866B;&#x7D30;&#x83CC;&#x3067;&#x3042;&#x308B;&#x3002;&#x7DDA;&#x866B;&#x3001;&#x7D30;&#x83CC;&#x306E;&#x30DA;&#x30A2;&#x306F;&#x3001;&#x6606;&#x866B;&#x75C5;&#x539F;&#x6027;&#x3068;&#x5229;&#x7528;&#x53EF;&#x80FD;&#x306A;&#x6606;&#x866B;&#x7531;&#x6765;&#x306E;&#x6804;&#x990A;&#x7D20;&#x304B;&#x3089;&#x3001;&#x7DDA;&#x866B;&#x306B;&#x6804;&#x990A;&#x3092;&#x63D0;&#x4F9B;&#x3059;&#x308B;&#x7D30;&#x83CC;&#x306B;&#x8CA2;&#x732E;&#x3057;&#x3066;&#x4E21;&#x65B9;&#x306E;&#x30D1;&#x30FC;&#x30C8;&#x30CA;&#x30FC;&#x3067;&#x3001;&#x6606;&#x866B;&#x306B;&#x611F;&#x67D3;&#x3057;&#x3001;&#x6BBA;&#x3059;&#x3002;&#x7DDA;&#x866B;&#x306F;&#x3001;&#x6355;&#x98DF;&#x8005;&#x3001;&#x6804;&#x990A;&#x3078;&#x306E;&#x30A2;&#x30AF;&#x30BB;&#x30B9;&#x3001;&#x304A;&#x3088;&#x3073;&#x5206;&#x6563;&#x306E;&#x30E1;&#x30AB;&#x30CB;&#x30BA;&#x30E0;&#x304B;&#x3089;&#x4FDD;&#x8B77;&#x3055;&#x308C;&#x308B;&#x7D30;&#x83CC;&#x3092;&#x63D0;&#x4F9B;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x7D30;&#x83CC;&#x5C5E;&#x306E;&#x30E1;&#x30F3;&#x30D0;&#x30FC;&#x306F;&#x3001;&#x6606;&#x866B;&#x3092;&#x6BBA;&#x3059;&#x305F;&#x3081;&#x306B;&#x7DDA;&#x866B;&#x3067;&#x3082;&#x6E96;Photorhabdus&#x3001;&#x7D30;&#x83CC;&#x306E;&#x4E21;&#x65B9;&#x306E;&#x5C5E;&#x306F;&#x3001;&#x56FA;&#x6709;&#x306E;&#x751F;&#x7406;&#x5B66;&#x7684;&#x304A;&#x3088;&#x3073;&#x4EE3;&#x8B1D;&#x30E1;&#x30AB;&#x30CB;&#x30BA;&#x30E0;&#x3092;&#x4ECB;&#x3057;&#x3066;&#x305D;&#x308C;&#x305E;&#x308C;&#x7570;&#x306A;&#x308B;&#x7DDA;&#x866B;&#x306E;&#x30DB;&#x30B9;&#x30C8;&#x306B;&#x540C;&#x69D8;&#x306E;&#x30B5;&#x30FC;&#x30D3;&#x30B9;&#x3092;&#x63D0;&#x4F9B;&#x3057;&#x3066;&#x3044;&#x307E;&#x3059;&#x3002;&#x6211;&#x3005;&#x306F;&#x3001;&#x3053;&#x308C;&#x3089;&#x306E;&#x9055;&#x3044;&#x306F;&#x305D;&#x308C;&#x305E;&#x308C;&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x306B;&#x53CD;&#x6620;&#x3055;&#x308C;&#x308B;&#x3053;&#x3068;&#x3092;&#x4EEE;&#x5B9A;&#x3057;&#x305F;&#x3002;&#x3053;&#x308C;&#x3092;&#x30C6;&#x30B9;&#x30C8;&#x3059;&#x308B;&#x306B;&#x306F;&#x3001;&#x6211;&#x3005;&#x306F;&#x6700;&#x5F8C;&#x307E;&#x3067;Xenorhabdus nematophila ATCC 19061&#x3068;Xenorhabdus bovienii SS-2004&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x3092;&#x914D;&#x5217;&#x6C7A;&#x5B9A;&#x3057;&#x305F;&#x3002;&#x4E88;&#x60F3;&#x901A;&#x308A;&#x3001;&#x4E21;&#x65B9;Xenorhabdus&#x30B2;&#x30CE;&#x30E0;&#x306F;&#x3001;&#x6606;&#x866B;&#x306E;&#x30E9;&#x30A4;&#x30D5;&#x30B9;&#x30BF;&#x30A4;&#x30EB;&#x306B;&#x898B;&#x5408;&#x3063;&#x305F;&#x591A;&#x304F;&#x306E;&#x6297;&#x6BBA;&#x866B;&#x5316;&#x5408;&#x7269;&#x3092;&#x3001;&#x30A8;&#x30F3;&#x30B3;&#x30FC;&#x30C9;&#x3057;&#x307E;&#x3059;&#x3002; Xenorhabdus&#x3068;Photorhabdus&#x7D30;&#x83CC;&#x3001;Xenorhabdus&#x306E;&#x6BD4;&#x8F03;&#x5206;&#x6790;&#x3001;Photorhabdus luminescens&#x3001;&#x304A;&#x3088;&#x3073;P. asymbiotica&#x306E;&#x30B2;&#x30CE;&#x30E0;&#x306E;&#x9593;&#x306B;&#x30E9;&#x30A4;&#x30D5;&#x30B9;&#x30BF;&#x30A4;&#x30EB;&#x306E;&#x985E;&#x4F3C;&#x6027;&#x306B;&#x3082;&#x304B;&#x304B;&#x308F;&#x3089;&#x305A;&#x3001;&#x30B2;&#x30CE;&#x30E0;&#x306E;&#x76F8;&#x9055;&#x3092;&#x793A;&#x5506;&#x3057;&#x3066;&#x3044;&#x308B;&#x3002;&#x3053;&#x308C;&#x3089;&#x306E;&#x77E5;&#x898B;&#x306F;&#x3001;&#x5171;&#x751F;&#x7684;&#x306A;&#x76F8;&#x4E92;&#x4F5C;&#x7528;&#x306B;&#x3088;&#x3063;&#x3066;&#x5F62;&#x4F5C;&#x3089;&#x9032;&#x5316;&#x7684;&#x5909;&#x5316;&#x306F;&#x3001;&#x540C;&#x69D8;&#x306E;&#x30A8;&#x30F3;&#x30C9;&#x30DD;&#x30A4;&#x30F3;&#x30C8;&#x3092;&#x9054;&#x6210;&#x3059;&#x308B;&#x305F;&#x3081;&#x306B;&#x5225;&#x306E;&#x30EB;&#x30FC;&#x30C8;&#x306B;&#x5F93;&#x3046;&#x3053;&#x3068;&#x304C;&#x3067;&#x304D;&#x308B;&#x3053;&#x3068;&#x3092;&#x793A;&#x3057;&#x307E;&#x3059;&#x3002;

&#x767A;&#x6563;&#x30B2;&#x30CE;&#x30E0;&#x304B;&#x3089;&#x53CE;&#x675F;&#x30E9;&#x30A4;&#x30D5;&#x30B9;&#x30BF;&#x30A4;&#x30EB;&#xFF1A;&#x6606;&#x866B;&#x75C5;&#x539F;&#x5171;&#x751F;&#x7D30;&#x83CC;&#x306E;Xenorhabdus&#x3068;Photorhabdus

&#xC18D;&#xC758; &#xBA64;&#xBC84; Xenorhabdus nematodes&#xC744; &#xC5F0;&#xACB0; &#xD558;&#xB294; &#xACE4;&#xCDA9; &#xBCD1;&#xC6D0; &#xC131; &#xBC15;&#xD14C;&#xB9AC;&#xC544;&#xB294;. &#xC120; &#xCDA9; &#xB958;-&#xBC15;&#xD14C;&#xB9AC;&#xC544; &#xC30D; &#xAC10;&#xC5FC; &#xBC0F; &#xACE4;&#xCDA9; pathogenesis &#xBC0F; &#xC0AC;&#xC6A9; &#xAC00;&#xB2A5;&#xD55C; &#xACE4;&#xCDA9; &#xC720;&#xB798; &#xC601;&#xC591;&#xC18C;&#xC5D0;&#xC11C;&#xB294; &#xC120; &#xCDA9; &#xB958;&#xB97C; &#xC81C;&#xACF5; &#xD558;&#xB294; &#xC601;&#xC591; &#xBC15;&#xD14C;&#xB9AC;&#xC544;&#xC5D0; &#xAE30;&#xC5EC; &#xD558;&#xB294; &#xB450; &#xD30C;&#xD2B8;&#xB108;&#xC640; &#xD568;&#xAED8; &#xACE4;&#xCDA9;&#xC744; &#xC8FD;&#xC774;&#xACE0;. &#xC120; &#xCDA9; &#xB958;&#xB294; &#xC721; &#xC2DD; &#xB3D9;&#xBB3C;, &#xC601;&#xC591;&#xC18C;&#xC5D0; &#xB300; &#xD55C; &#xC561;&#xC138;&#xC2A4; &#xBC0F; &#xBD84;&#xC0B0; &#xBA54;&#xCEE4;&#xB2C8;&#xC998;&#xC5D0;&#xC11C; &#xBCF4;&#xD638;&#xC640; &#xBC15;&#xD14C;&#xB9AC;&#xC544;&#xB97C; &#xC81C;&#xACF5;&#xD569;&#xB2C8;&#xB2E4;. &#xC138;&#xADE0; &#xC18D; Photorhabdus&#xC758; &#xAD6C;&#xC131;&#xC6D0; &#xB610;&#xD55C; nematodes&#xC744; &#xACE4;&#xCDA9;&#xC744; &#xC8FD; &#xC77C; &#xC5F0;&#xACB0; &#xD558; &#xACE0; &#xB450; &#xC18D; &#xBC15;&#xD14C;&#xB9AC;&#xC544;&#xC758; &#xB3C5;&#xD2B9;&#xD55C; &#xC0DD;&#xB9AC; &#xBC0F; &#xB300;&#xC0AC; &#xBA54;&#xCEE4;&#xB2C8;&#xC998;&#xC744; &#xD1B5;&#xD574; &#xADF8;&#xB4E4;&#xC758; &#xC11C;&#xB85C; &#xB2E4;&#xB978; &#xC120; &#xCDA9; &#xB958; &#xD638;&#xC2A4;&#xD2B8;&#xB97C; &#xC720;&#xC0AC;&#xD55C; &#xC11C;&#xBE44;&#xC2A4;&#xB97C; &#xC81C;&#xACF5; &#xD569;&#xB2C8;&#xB2E4;. &#xC6B0;&#xB9AC;&#xB294; &#xC774;&#xB7EC;&#xD55C; &#xCC28;&#xC774; &#xAC01; &#xAC8C;&#xB188;&#xC5D0; &#xBC18;&#xC601; &#xB420; &#xAC83; &#xC774;&#xB77C;&#xACE0; posited. &#xC774; &#xD14C;&#xC2A4;&#xD2B8; &#xD558;&#xB824;&#xBA74; &#xC6B0;&#xB9AC; &#xC2DC;&#xD000;&#xC2A4; &#xC644;&#xB8CC; Xenorhabdus nematophila ATCC 19061&#xC758; &#xC720;&#xC804;&#xC790;&#xC640; Xenorhabdus bovienii SS-2004. &#xC608;&#xC0C1; &#xB300;&#xB85C;, &#xBAA8;&#xB450; Xenorhabdus &#xC720;&#xC804;&#xC790; &#xB9CE;&#xC740; anti-insecticidal &#xD654;&#xD569;&#xBB3C;, &#xACE4;&#xCDA9; &#xBCD1;&#xC6D0; &#xC131; &#xB77C;&#xC774;&#xD504; &#xC2A4;&#xD0C0;&#xC77C;&#xC5D0; &#xC54C;&#xB9DE;&#xC740; &#xC778;&#xCF54;&#xB529;. Xenorhabdus &#xBC0F; Photorhabdus &#xBC15;&#xD14C;&#xB9AC;&#xC544;, Xenorhabdus, Photorhabdus luminescens&#xC758; &#xBE44;&#xAD50; &#xBD84;&#xC11D; &#xAC04;&#xC758; &#xC0DD;&#xD65C;&#xC758; &#xC720;&#xC0AC;&#xC131;&#xC5D0;&#xB3C4; &#xBD88;&#xAD6C; &#xD558; &#xACE0; P. asymbiotica &#xC720;&#xC804;&#xC790; &#xAC8C;&#xB188; &#xBC1C;&#xC0B0;&#xC744; &#xC81C;&#xC548; &#xD558; &#xACE0;. &#xC774;&#xB7EC;&#xD55C; &#xC5F0;&#xAD6C; &#xACB0;&#xACFC; &#xC9C4;&#xD654; &#xBCC0;&#xD654; &#xACF5;&#xC0DD; &#xC791;&#xC6A9;&#xC5D0; &#xC758;&#xD574; &#xD615;&#xC131; &#xBE44;&#xC2B7;&#xD55C; &#xC5D4;&#xB4DC; &#xD3EC;&#xC778;&#xD2B8;&#xB97C; &#xB2EC;&#xC131; &#xD558;&#xAE30; &#xC704;&#xD574; &#xC11C;&#xB85C; &#xB2E4;&#xB978; &#xACBD;&#xB85C; &#xB530;&#xB97C; &#xC218; &#xB098;&#xD0C0;&#xB0C5;&#xB2C8;&#xB2E4;.

&#xACE4;&#xCDA9; &#xBCD1;&#xC6D0; &#xC131; &#xC138;&#xADE0; endosymbionts Xenorhabdus &#xBC0F; Photorhabdus: &#xBD84;&#xAE30; &#xAC8C;&#xB188;&#xC5D0;&#xC11C; &#xC9D1;&#xC911; &#xB77C;&#xC774;&#xD504; &#xC2A4;&#xD0C0;&#xC77C;.

Los miembros de las Xenorhabdus g&#xE9;nero son bacterias entomopat&#xF3;genos que se asocian con los nematodos. La pareja de nematodos-bacteria infecta y mata a los insectos, con los dos socios que contribuyen a la patog&#xE9;nesis de los insectos y las bacterias proporcionar nutrici&#xF3;n a los nematodos de los insectos disponibles derivados de nutrientes. El nematodo proporciona la bacteria con la protecci&#xF3;n de los depredadores, el acceso a los nutrientes, y un mecanismo de dispersi&#xF3;n. Los miembros de los g&#xE9;neros bacterianos Photorhabdus tambi&#xE9;n asociado con los nematodos para matar insectos, y los dos g&#xE9;neros de bacterias prestar servicios similares a sus anfitriones a trav&#xE9;s de diferentes nematodos &#xFA;nicos mecanismos fisiol&#xF3;gicos y metab&#xF3;licos. Hemos planteado que estas diferencias se reflejan en sus respectivos genomas. Para probar esto, hemos secuenciado los genomas hasta la finalizaci&#xF3;n de Xenorhabdus nematophila ATCC 19061 y Xenorhabdus bovienii SS-2004. Como era de esperar, ambos genomas Xenorhabdus codificar muchos anti-compuestos insecticidas, en consonancia con su estilo de vida entomopat&#xF3;geno. A pesar de las similitudes en el estilo de vida entre Xenorhabdus y bacterias Photorhabdus, un an&#xE1;lisis comparativo de los Xenorhabdus Photorhabdus luminescens, y los genomas de P. asymbiotica sugiere divergencia gen&#xF3;mica. Estos hallazgos indican que los cambios evolutivos conformadas por las interacciones simbi&#xF3;ticas pueden seguir diferentes rutas para alcanzar los puntos finales similares.

Los entomopat&#xF3;genos Xenorhabdus endosimbiontes bacterianos y Photorhabdus: Estilos de vida convergentes de genomas divergentes

The xnp1 remnant P2-type prophage of Xenorhabdus nematophila produces xenorhabdicin that is active against closely related species. Xenorhabdicin had not been characterized previously in other Xenorhabdus species. Here, we show xenorhabdicin production in six different strains of Xenorhabdus bovienii. The sequenced genome of X. bovienii SS-2004 was found to possess a highly conserved remnant P2-type cluster (xbp1). Inactivation of the xbpS1 sheath gene resulted in loss of bacteriocin activity, indicating that the xbp1 locus was required for xenorhabdicin production. xbp1 and xnp1 contain a CI-type repressor, a dinI gene involved in stabilization of ssDNA-RecA complexes and are inducible with mitomycin C, suggesting that both loci are regulated by cleavage of the CI repressor. Both xnp1 and xbp1 lack typical P2-type lysis genes but contain a predicted endolysin gene (enp) that may be involved in cell lysis. The main tail fibers of xnp1 and xbp1 are mosaic structures with divergent C-terminal regions suggesting they differ in host specificity. Several genes encoding C-terminal tail fiber fragments are present in the same position in xnp1 and xbp1. Recombination between the main fiber genes and the C-terminal fragments could potentially expand the host range specificity of xenorhabdicin in the respective strains.

Comparative analysis of P2-type remnant prophage loci in Xenorhabdus bovienii and Xenorhabdus nematophila required for xenorhabdicin production.

Metabolism of iron derived from insoluble and/or scarce sources is essential for pathogenic and environmental microbes. The ability of Pseudomonas aeruginosa to acquire iron from exogenous ferritin was assessed; ferritin is an iron-concentrating and antioxidant protein complex composed of a catalytic protein and caged ferrihydrite nanomineral synthesized from Fe(II) and O(2) or H(2)O(2). Ferritin and free ferrihydrite supported growth of P. aeruginosa with indistinguishable kinetics and final culture densities. The P. aeruginosa PAO1 mutant (ΔpvdDΔpchEF), which is incapable of siderophore production, grew as well as the wild type when ferritin was the iron source. Such data suggest that P. aeruginosa can acquire iron by siderophore-independent mechanisms, including secretion of small-molecule reductant(s). Protease inhibitors abolished the growth of the siderophore-free strain on ferritins, with only a small effect on growth of the wild type; predictably, protease inhibitors had no effect on growth with free ferrihydrite as the iron source. Proteolytic activity was higher with the siderophore-free strain, suggesting that the role of proteases in the degradation of ferritin is particularly important for iron acquisition in the absence of siderophores. The combined results demonstrate the importance of both free ferrihydrite, a natural environmental form of iron and a model for an insoluble form of partly denatured ferritin called hemosiderin, and caged ferritin iron minerals as bacterial iron sources. Ferritin is also revealed as a growth promoter of opportunistic, pathogenic bacteria such a P. aeruginosa in diseased tissues such as the cystic fibrotic lung, where ferritin concentrations are abnormally high.

Ferritin and ferrihydrite nanoparticles as iron sources for Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a ubiquitous bacterium that survives in many environments, including as an acute and chronic pathogen in humans. Substantial evidence shows that P. aeruginosa behavior is affected by its motility, and appendages known as flagella and type IV pili (TFP) are known to confer such motility. The role these appendages play when not facilitating motility or attachment, however, is unclear. Here we discern a passive intercellular role of TFP during flagellar-mediated swarming of P. aeruginosa that does not require TFP extension or retraction. We studied swarming at the cellular level using a combination of laboratory experiments and computational simulations to explain the resultant patterns of cells imaged from in vitro swarms. Namely, we used a computational model to simulate swarming and to probe for individual cell behavior that cannot currently be otherwise measured. Our simulations showed that TFP of swarming P. aeruginosa should be distributed all over the cell and that TFP-TFP interactions between cells should be a dominant mechanism that promotes cell-cell interaction, limits lone cell movement, and slows swarm expansion. This predicted physical mechanism involving TFP was confirmed in vitro using pairwise mixtures of strains with and without TFP where cells without TFP separate from cells with TFP. While TFP slow swarm expansion, we show in vitro that TFP help alter collective motion to avoid toxic compounds such as the antibiotic carbenicillin. Thus, TFP physically affect P. aeruginosa swarming by actively promoting cell-cell association and directional collective motion within motile groups to aid their survival.

Nydia Morales-Soto

Department of Civil and Environmental Engineering and Earth Sciences,
Eck Institute for Global Health

University of Notre Dame

Preparation, Imaging, and Quantification of Bacterial Surface Motility Assays

Nydia Morales-Soto

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Civil and Environmental Engineering and Earth Sciences,Eck Institute for Global Health

University of Notre Dame

Preparation, Imaging, and Quantification of Bacterial Surface Motility Assays

Department of Civil and Environmental Engineering and Earth Sciences,
Eck Institute for Global Health