Cette étude a été financée par des subventions de recherche Le Comité pour l&#39;Université d&#39;Antioquia (CODI), L&#39;Institut colombien pour le développement de la science et la technologie - COLCIENCIAS et le Centre pour le développement de produits contre les maladies tropicales - CIDEPRO.

<ol>
	<li>WHO. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+the+leishmaniasis.">Control of the leishmaniasis.</a> Report of a Meeting of the WHO Expert Committee on the Control of Leishmaniasis WHO. 949, (2010).</li><li>Titus, R. G., Marchand, M., Boon, T., Louis, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+limiting+dilution+assay+for+quantifying+Leishmania+major+in+tissues+of+infected+mice.">A limiting dilution assay for quantifying Leishmania major in tissues of infected mice.</a> Parasite Immunol. 7, 545-555 (1985).</li><li>Reynolds, K. 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+Kodak+Ektachem+dry+layer+technology+for+clinical+chemistry.">The Kodak Ektachem dry layer technology for clinical chemistry.</a> Upsala. J. Med. Sci. 91, 143-146 (1986).</li><li>Handman, E., Ceredig, R., Mitchell, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+cutaneous+leishmaniasis:+disease+patterns+in+intact+and+nude+mice+of+various+genotypes+and+examination+of+some+differences+between+normal+and+infected+macrophages.">Murine cutaneous leishmaniasis: disease patterns in intact and nude mice of various genotypes and examination of some differences between normal and infected macrophages.</a> Australian J. Exp. Biol. Med. Sci. 57, 9-29 (1979).</li><li>Hanson, W., Chapman, W., Waits, V., Lovelace, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+Leishmania+(Viannia)+panamensis+lesions+and+relationship+of+numbers+of+amastigotes+to+lesion+area+antimony-treated+and+untreated+hamsters.">Development of Leishmania (Viannia) panamensis lesions and relationship of numbers of amastigotes to lesion area antimony-treated and untreated hamsters.</a> J. Parasitol. 77, 780-783 (1991).</li><li>Henao, H. H., Osorio, Y., Saravia, N. G., G&#243;mez, A., Travi, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+and+toxicity+of+pentavalentantimonials+(Glucantime+and+Pentostam)+in+an+American+cutaneous+leishmaniasis+animal+model:+luminometry+application.">Efficacy and toxicity of pentavalentantimonials (Glucantime and Pentostam) in an American cutaneous leishmaniasis animal model: luminometry application.</a> Biom&#233;dica. 24, 393-402 (2004).</li><li>Travi, B. L., Martinez, J. E., Zea, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antimonial+treatment+of+hamsters+infected+with+Leishmania+(Viannia)+panamensis:+assessment+of+parasitological+cure+with+different+therapeutic+schedules.">Antimonial treatment of hamsters infected with Leishmania (Viannia) panamensis: assessment of parasitological cure with different therapeutic schedules.</a> Trans. R. Soc. Trop. Med. Hyg. 87, 567-569 (1993).</li><li>Hommel, M., jaffe, C. L., Travi, B., Milon, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+models+for+leishmaniasis+and+for+testing+anti-leishmanial+vaccines.">Experimental models for leishmaniasis and for testing anti-leishmanial vaccines.</a> Ann. Trop. Med. Parasitol. 89, 55-73 (1995).</li><li>Travi, B. L., Osorio, Y., Saravia, N. 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+inflammatory+response+promotes+cutaneous+metastasis+in+hamsters+infected+with+Leishmania+(Viannia)+panamensis.">The inflammatory response promotes cutaneous metastasis in hamsters infected with Leishmania (Viannia) panamensis.</a> J. Parasitol. 82, 454-457 (1996).</li><li>Travi, B. L., Osorio, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Failure+of+Albendazole+as+an+alternative+treatment+of+cutaneous+Leishmaniasis+in+the+hamster+model.">Failure of Albendazole as an alternative treatment of cutaneous Leishmaniasis in the hamster model.</a> Memorias Instituto Oswaldo. 93, 515 (1998).</li><li>Travi, B. L., Osorio, Y., Melby, P. C., Chandrasekar, B., Arteaga, L., Saravia, N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gender+is+a+major+determinant+of+the+clinical+evolution+and+immune+response+in+hamsters+infected+with+Leishmania+spp.">Gender is a major determinant of the clinical evolution and immune response in hamsters infected with Leishmania spp.</a> Infect Immun. 70, 2288-2296 (2002).</li><li>Osorio, Y., Melby, P. C., Pirmez, C., Chandrasekar, B., Guar&#237;n, N., Travi, 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=The+site+of+cutaneous+infection+influences+the+immunological+response+and+clinical+outcome+of+hamsters+infected+with+Leishmania+panamensis.">The site of cutaneous infection influences the immunological response and clinical outcome of hamsters infected with Leishmania panamensis.</a> Parasite Immunol. 25, 139-148 (2003).</li><li>Osorio, Y., Bonilla, D. L., Peniche, A. G., Melby, P. C., Travi, 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=Pregnancy+enhances+the+innate+immune+response+in+experimental+cutaneous+leishmaniasis+through+hormone-modulated+nitric+oxide+production.">Pregnancy enhances the innate immune response in experimental cutaneous leishmaniasis through hormone-modulated nitric oxide production.</a> J. Leukoc. Biol. 83, 1413-1422 (2008).</li><li>Espitia, C. M., Zhao, W., Saldarriaga, O., Osorio, Y., Harrison, L. M., Cappello, M., Travi, B. L., Melby, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Duplex+real-time+reverse+transcriptase+PCR+to+determine+cytokine+mRNA+expression+in+a+hamster+model+of+New+World+cutaneous+leishmaniasis.">Duplex real-time reverse transcriptase PCR to determine cytokine mRNA expression in a hamster model of New World cutaneous leishmaniasis.</a> BMC Immunol. 22, 11-31 (2010).</li></ol>

Pas de conflits d&#39;intérêt déclarés.

La leishmaniose cutanée est endémique dans les régions tropicales et néotropicales. Il est souvent désigné comme un groupe de maladies à cause du spectre de manifestations cliniques variées, qui vont de petits nodules cutanés à la destruction du tissu brut muqueuse. La plupart des médicaments disponibles sont coûteux, nécessitent des traitements longs et sont de plus en plus inefficaces, ce qui nécessite la découverte de nouveaux médicaments. Le modèle de souris est largemen...

<table border="1"><tbody><tr><td> Nom du réactif </td><td> Type </td><td> Entreprise </td><td> Numéro de catalogue </td></tr><tr><td> La kétamine </td><td> Réactif </td><td> Holliday-Scott SA </td><td></td></tr><tr><td> Xilacine </td><td> Réactif </td><td> Synthèse </td><td></td></tr><tr><td> PBS </td><td> Réactif </td><td> GIBCO </td><td> 14190-136 </td></tr><tr><td> Pied à coulisse digital </td><td> Équipement </td><td> Pêcheur </td><td> 15-077-958 </td></tr><tr><td> Giemsa </td><td> Réactif </td><td> SIGMA </td><td> GS1L-1L </td></tr><tr><td> Formol </td><td> Réactif </td><td> Nouvelle-laboratoire </td><td> 11273 </td></tr><tr><td> Paraffine </td><td> Réactif </td><td> Pechiney Plastic Packaging </td><td> PM-996 </td></tr><tr><td> Haemotoxilin </td><td> Réactif </td><td> Nouvelle-laboratoire </td><td&gt; 10870103 </td></tr><tr><td> Eosine </td><td></td><td> Nouvelle-laboratoire </td><td> 10870203 </td></tr><tr><td> Kodak Ektachem sèche chimie </td><td> Équipement </td><td> Kodak Ektachem </td><td> DT-60 </td></tr><tr><td> antimoniate de méglumine </td><td> Réactif </td><td> Aventis </td><td></td></tr><tr><td> Microscopie </td><td> Équipement </td><td> Nikon </td><td> YS2-T </td></tr></tbody></table>

cutaneous leishmaniasis in the dorsal skin of hamsters: a useful model for the screening of antileishmanial drugs

Traditionnellement, les hamsters sont expérimentalement inoculés dans le museau ou la patte. Toutefois, dans ces sites un ulcère n&#39;est pas toujours lieu, la mesure de la taille des lésions est une procédure difficile et les animaux montrent des difficultés à manger, respirer et bouger à cause de la lésion. Afin d&#39;optimiser le modèle du hamster pour la leishmaniose cutanée, jeune mâle adulte et femelle hamsters dorés (Mesocricetus auratus) ont été injectés par voie intradermique à la peau du dos avec 1 à 1,5 x l0 7 promastigotes de Leishmania et la progression des lésions subséquentes ont été évaluées pour un maximum de 16 semaines après l&#39;infection. Le hamster doré a été choisi parce qu&#39;il est considéré comme le modèle bio-suffisante pour évaluer les médicaments contre la Leishmania car ils sont sensibles à l&#39;infection par différentes espèces. Infection cutanée des résultats hamsters dans les lésions chroniques, mais contrôlée, et une évolution clinique avec des signes semblables à ceux observés chez l&#39;homme. Par conséquent, la mise en place of la mesure de l&#39;infection par mesure de la taille de la lésion selon l&#39;une matière de indurations et les ulcères est réalisable. Cette approche a prouvé sa polyvalence et une gestion facile lors de l&#39;inoculation, le suivi et la caractérisation des lésions typiques (ulcères), l&#39;application de traitements par le biais de différentes manières et l&#39;obtention d&#39;échantillons cliniques après différents traitements. En utilisant cette méthode, la qualité de la vie animale en ce qui concerne la locomotion, la recherche de nourriture et d&#39;eau, des activités ludiques et sociaux est également préservé.

Watch this Scientific Journal Video about Cutaneous Leishmaniasis in the Dorsal Skin of Hamsters: a Useful Model for the Screening of Antileishmanial Drugs at JoVE.com

Cutaneous Leishmaniasis in the Dorsal Skin of Hamsters: a Useful Model for the Screening of Antileishmanial Drugs

Optimisation du modèle hamster expérimental pour la leishmaniose cutanée par injection intradermique de<em&gt; Leishmania</em&gt; Promastigotes à la peau du dos. Cette approche est utile lors de l&#39;inoculation, suivi, la caractérisation des lésions, l&#39;application de traitements et d&#39;obtenir des échantillons cliniques. Locomotion, la recherche de nourriture et d&#39;eau, des activités ludiques et sociaux sont préservés.

La leishmaniose cutanée dans la peau dorsale de Hamsters: un modèle utile pour le dépistage des drogues antileishmanienne

Traditionally, hamsters are experimentally inoculated in the snout or the footpad. However in these sites an ulcer not always occurs, measurement of ...

cutaneous-leishmaniasis-dorsal-skin-hamsters-useful-model-for

Research

JoVE Journal

Immunology and Infection

21.8K vues.  University of Antioquia. Optimisation du modèle hamster expérimental pour la leishmaniose cutanée par injection intradermique de Leishmania Promastigotes à la peau du dos. Cette approche est utile lors de l'inoculation, suivi, la caractérisation des lésions, l'application de traitements et d'obtenir des échantillons cliniques. Locomotion, la recherche de nourriture et d'eau, des activités ludiques et sociaux sont préservés.

Vidéo: Cutaneous Leishmaniasis in the Dorsal Skin of Hamsters: a Useful Model for the Screening of Antileishmanial Drugs

Induction of Graft-versus-host Disease and In Vivo T Cell Monitoring Using an MHC-matched Murine Model

Graft-versus-host disease (GVHD) is the limiting barrier to the broad use of bone marrow transplant as a curative therapy for a variety of hematological deficiencies. GVHD is caused by mature alloreactive T cells present in the bone marrow graft that are infused into the recipient and cause damage to host organs. However, in mice, T cells must be added to the bone marrow inoculum to cause GVHD. Although extensive work has been done to characterize T cell responses post transplant, bioluminescent imaging technology is a non-invasive method to monitor T cell trafficking patterns in vivo. 
Following lethal irradiation, recipient mice are transplanted with bone marrow cells and splenocytes from donor mice. T cell subsets from L2G85.B6 (transgenic mice that constitutively express luciferase) are included in the transplant. By only transplanting certain T cell subsets, one is able to track specific T cell subsets in vivo, and based on their location, develop hypotheses regarding the role of specific T cell subsets in promoting GVHD at various time points. At predetermined intervals post transplant, recipient mice are imaged using a Xenogen IVIS CCD camera. Light intensity can be quantified using Living Image software to generate a pseudo-color image based on photon intensity (red = high intensity, violet = low intensity). 
Between 4-7 days post transplant, recipient mice begin to show clinical signs of GVHD. Cooke et al.1 developed a scoring system to quantitate disease progression based on the recipient mice fur texture, skin integrity, activity, weight loss, and posture. Mice are scored daily, and euthanized when they become moribund. Recipient mice generally become moribund 20-30 days post transplant. 
Murine models are valuable tools for studying the immunology of GVHD. Selectively transplanting particular T cell subsets allows for careful identification of the roles each subset plays. Non-invasively tracking T cell responses in vivo adds another layer of value to murine GVHD models.

Induction of Graft-versus-host Disease and In Vivo T Cell Monitoring Using an MHC-matched Murine Model

Murine bone marrow transplantation is a widely used technique to study immunological mechanisms governing graft-versus-host disease in humans. The ability to monitor T cell trafficking patterns in vivo allows for detailed analysis of the development and perpetuation of T cell responses during graft-versus-host disease.

L&#39;induction de la réaction du greffon contre l&#39;hôte et des maladies<em&gt; In Vivo</em&gt; Suivi des lymphocytes T utilisant un modèle murin MHC-apparié

Graft-versus-host disease (GVHD) is the limiting barrier to the broad use of bone marrow transplant as a curative therapy for a variety of hematological ...

Recherche

Immunologie et infection

A Parasite Rescue and Transformation Assay for Antileishmanial Screening Against Intracellular Leishmania donovani Amastigotes in THP1 Human Acute Monocytic Leukemia Cell Line

Leishmaniasis is one of the world's most neglected diseases, largely affecting the poorest of the poor, mainly in developing countries. Over 350 million people are considered at risk of contracting leishmaniasis, and approximately 2 million new cases occur yearly1. Leishmania donovani is the causative agent for visceral leishmaniasis (VL), the most fatal form of the disease. The choice of drugs available to treat leishmaniasis is limited 2;current treatments provide limited efficacy and many are toxic at therapeutic doses. In addition, most of the first line treatment drugs have already lost their utility due to increasing multiple drug resistance 3. The current pipeline of anti-leishmanial drugs is also severely depleted. Sustained efforts are needed to enrich a new anti-leishmanial drug discovery pipeline, and this endeavor relies on the availability of suitable in vitro screening models.
In vitro promastigotes 4 and axenic amastigotes assays5 are primarily used for anti-leishmanial drug screening however, may not be appropriate due to significant cellular, physiological, biochemical and molecular differences in comparison to intracellular amastigotes. Assays with macrophage-amastigotes models are considered closest to the pathophysiological conditions of leishmaniasis, and are therefore the most appropriate for in vitro screening. Differentiated, non-dividing human acute monocytic leukemia cells (THP1) (make an attractive) alternative to isolated primary macrophages and can be used for assaying anti-leishmanial activity of different compounds against intracellular amastigotes.
Here, we present a parasite-rescue and transformation assay with differentiated THP1 cells infected in vitro with Leishmania donovani for screening pure compounds and natural products extracts and determining the efficacy against the intracellular Leishmania amastigotes. The assay involves the following steps: (1) differentiation of THP1 cells to non-dividing macrophages, (2) infection of macrophages with L. donovani metacyclic promastigotes, (3) treatment of infected cells with test drugs, (4) controlled lysis of infected macrophages, (5) release/rescue of amastigotes and (6) transformation of live amastigotes to promastigotes. The assay was optimized using detergent treatment for controlled lysis of Leishmania-infected THP1 cells to achieve almost complete rescue of viable intracellular amastigotes with minimal effect on their ability to transform to promastigotes. Different macrophage:promastigotes ratios were tested to achieve maximum infection. Quantification of the infection was performed through transformation of live, rescued Leishmania amastigotes to promastigotes and evaluation of their growth by an alamarBlue fluorometric assay in 96-well microplates. This assay is comparable to the currently-used microscopic, transgenic reporter gene and digital-image analysis assays. This assay is robust and measures only the live intracellular amastigotes compared to reporter gene and image analysis assays, which may not differentiate between live and dead amastigotes. Also, the assay has been validated with a current panel of anti-leishmanial drugs and has been successfully applied to large-scale screening of pure compounds and a library of natural products fractions (Tekwani et al. unpublished).

A Parasite Rescue and Transformation Assay for Antileishmanial Screening Against Intracellular Leishmania donovani Amastigotes in THP1 Human Acute Monocytic Leukemia Cell Line

A parasite-rescue and transformation assay with THP1 cells infected in vitro with Leishmania donovani has been optimized for anti-leishmanial drug screening. The assay involves differentiation of THP1 cells, infection with promastigotes, treatment with test drugs, controlled lysis of the infected macrophages, rescue of amastigotes, transformation to promastigotes and monitoring promastigote growth and proliferation with a fluorometric assay.

Un test Parasite sauvetage et à la transformation pour le dépistage anti-leishmaniose contre intracellulaire<em&gt; Leishmania donovani</em&gt; Amastigotes dans THP1 humaines ligne leucémie aiguë monocytaire cellulaire

Leishmaniasis is  one of the world's most neglected diseases, largely affecting the  poorest of the poor, mainly in developing countries. Over 350 million ...

A New Screening Method for the Directed Evolution of Thermostable Bacteriolytic Enzymes

Directed evolution is defined as a method to harness natural selection in order to engineer proteins to acquire particular properties that are not associated with the protein in nature. Literature has provided numerous examples regarding the implementation of directed evolution to successfully alter molecular specificity and catalysis1. The primary advantage of utilizing directed evolution instead of more rational-based approaches for molecular engineering relates to the volume and diversity of variants that can be screened2. One possible application of directed evolution involves improving structural stability of bacteriolytic enzymes, such as endolysins. Bacteriophage encode and express endolysins to hydrolyze a critical covalent bond in the peptidoglycan (i.e. cell wall) of bacteria, resulting in host cell lysis and liberation of progeny virions. Notably, these enzymes possess the ability to extrinsically induce lysis to susceptible bacteria in the absence of phage and furthermore have been validated both in vitro and in vivo for their therapeutic potential3-5. The subject of our directed evolution study involves the PlyC endolysin, which is composed of PlyCA and PlyCB subunits6. When purified and added extrinsically, the PlyC holoenzyme lyses group A streptococci (GAS) as well as other streptococcal groups in a matter of seconds and furthermore has been validated in vivo against GAS7. Significantly, monitoring residual enzyme kinetics after elevated temperature incubation provides distinct evidence that PlyC loses lytic activity abruptly at 45 &deg;C, suggesting a short therapeutic shelf life, which may limit additional development of this enzyme. Further studies reveal the lack of thermal stability is only observed for the PlyCA subunit, whereas the PlyCB subunit is stable up to ~90 &deg;C (unpublished observation). In addition to PlyC, there are several examples in literature that describe the thermolabile nature of endolysins. For example, the Staphylococcus aureus endolysin LysK and Streptococcus pneumoniae endolysins Cpl-1 and Pal lose activity spontaneously at 42 &deg;C, 43.5 &deg;C and 50.2 &deg;C, respectively8-10. According to the Arrhenius equation, which relates the rate of a chemical reaction to the temperature present in the particular system, an increase in thermostability will correlate with an increase in shelf life expectancy11. Toward this end, directed evolution has been shown to be a useful tool for altering the thermal activity of various molecules in nature, but never has this particular technology been exploited successfully for the study of bacteriolytic enzymes. Likewise, successful accounts of progressing the structural stability of this particular class of antimicrobials altogether are nonexistent. In this video, we employ a novel methodology that uses an error-prone DNA polymerase followed by an optimized screening process using a 96 well microtiter plate format to identify mutations to the PlyCA subunit of the PlyC streptococcal endolysin that correlate to an increase in enzyme kinetic stability (Figure 1). Results after just one round of random mutagenesis suggest the methodology is generating PlyC variants that retain more than twice the residual activity when compared to wild-type (WT) PlyC after elevated temperature treatment.

A novel directed evolution method specific to the field of thermostability engineering was developed and consequently validated for bacteriolytic enzymes. After only one round of random mutagenesis, an evolved bacteriolytic enzyme, PlyC 29C3, displayed greater than twice the residual activity when compared to the wild-type protein after elevated temperature incubation.

Une nouvelle méthode de dépistage pour l&#39;évolution dirigée des enzymes thermostables bactériolytique

Directed evolution is defined as a method to harness natural selection in order to engineer proteins to acquire particular properties that are not ...

VIGS-Mediated Forward Genetics Screening for Identification of Genes Involved in Nonhost Resistance

Nonhost disease resistance of plants against bacterial pathogens is controlled by complex defense pathways. Understanding this mechanism is important for developing durable disease-resistant plants against wide range of pathogens. Virus-induced gene silencing (VIGS)-based forward genetics screening is a useful approach for identification of plant defense genes imparting nonhost resistance. Tobacco rattle virus (TRV)-based VIGS vector is the most efficient VIGS vector to date and has been efficiently used to silence endogenous target genes in Nicotiana benthamiana.

	In this manuscript, we demonstrate a forward genetics screening approach for silencing of individual clones from a cDNA library in N. benthamiana and assessing the response of gene silenced plants for compromised nonhost resistance against nonhost pathogens, Pseudomonas syringae pv. tomato T1, P. syringae pv. glycinea, and X. campestris pv. vesicatoria. These bacterial pathogens are engineered to express GFPuv protein and their green fluorescing colonies can be seen by naked eye under UV light in the nonhost pathogen inoculated plants if the silenced target gene is involved in imparting nonhost resistance. This facilitates reliable and faster identification of gene silenced plants susceptible to nonhost pathogens. Further, promising candidate gene information can be known by sequencing the plant gene insert in TRV vector. Here we demonstrate the high throughput capability of VIGS-mediated forward genetics to identify genes involved in nonhost resistance. Approximately, 100 cDNAs can be individually silenced in about two to three weeks and their relevance in nonhost resistance against several nonhost bacterial pathogens can be studied in a week thereafter. In this manuscript, we enumerate the detailed steps involved in this screening. VIGS-mediated forward genetics screening approach can be extended not only to identifying genes involved in nonhost resistance but also to studying genes imparting several biotic and abiotic stress tolerances in various plant species.

Virus-induced gene silencing is an useful tool for identifying genes involved in nonhost resistance of plants. We demonstrate the use of bacterial pathogens expressing GFPuv in identifying gene silenced plants susceptible to nonhost pathogens. This approach is easy, fast and facilitates large scale screening and similar protocol can be applied to studying various other plant-microbe interactions.

VIGS-Mediated dépistage génétique avant pour l&#39;identification des gènes impliqués dans la résistance non hôte


	Nonhost disease resistance of plants against bacterial pathogens is controlled by complex defense pathways. Understanding this mechanism is important ...

Visualizing the Effects of Sputum on Biofilm Development Using a Chambered Coverglass Model

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the development and persistence of many health related infections. One of the most well described and studied biofilms in human disease occurs in chronic pulmonary infection of cystic fibrosis patients. When studying biofilms in the context of the host, many factors can impact biofilm formation and development. In order to identify how host factors may affect biofilm formation and development, we used a static chambered coverglass method to grow biofilms in the presence of host-derived factors in the form of sputum supernatants. Bacteria are seeded into chambers and exposed to sputum filtrates. Following 48 hr of growth, biofilms are stained with a commercial biofilm viability kit prior to confocal microscopy and analysis. Following image acquisition, biofilm properties can be assessed using different software platforms. This method allows us to visualize key properties of biofilm growth in presence of different substances including antibiotics.

This protocol describes the visualization of biofilm development following exposure to host-factors using a slide chamber model. This model allows for direct visualization of biofilm development as well as analysis of biofilm parameters using computer software programs.

Visualisation des effets des expectorations sur le développement du biofilm Utilisation d&#39;un modèle Chambered lamelle couvre-objet

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the ...

Vasodilation of Isolated Vessels and the Isolation of the Extracellular Matrix of Tight-skin Mice

The interferon regulatory factor 5 (IRF5) is crucial for cells to determine if they respond in a pro-inflammatory or anti-inflammatory fashion. IRF5's ability to switch cells from one pathway to another is highly attractive as a therapeutic target. We designed a decoy peptide IRF5D with a molecular modeling software for designing small molecules and peptides.
IRF5D inhibited IRF5, reduced alterations in extracellular matrix, and improved endothelial vasodilation in the tight-skin mouse (Tsk/+). The Kd of IRF5D for recombinant IRF5 is 3.72 &plusmn; 0.74 x 10-6 M as determined by binding experiments using biolayer interferometry experiments. Endothelial cells (EC) proliferation and apoptosis were unchanged using increasing concentrations of IRF5D (0 to 100 &#181;g/mL, 24 h). Tsk/+ mice were treated with IRF5D (1 mg/kg/d subcutaneously, 21 d). IRF5 and ICAM expressions were decreased after IRF5D treatment. Endothelial function was improved as assessed by vasodilation of facialis arteries from Tsk/+ mice treated with IRF5D compared to Tsk/+ mice without IRF5D treatment. As a transcription factor, IRF5 traffics from the cytosol to the nucleus. Translocation was assessed by immunohistochemistry on cardiac myocytes cultured on the different cardiac extracellular matrices. IRF5D treatment of the Tsk/+ mouse resulted in a reduced number of IRF5 positive nuclei in comparison to the animals without IRF5D treatment (50 &#181;g/mL, 24 h). These findings demonstrate the important role that IRF5 plays in inflammation and fibrosis in Tsk/+ mice.

We describe the isolation of cardiac extracellular matrix from C57Bl/6J control mice, tight-skin mice, and tight-skin mice treated with the IRF5 inhibitory peptide. We also describe the vasodilation studies on the isolated vessels from C57Bl/6J, tight-skin mice and tight-skin mice treated with the IRF5 inhibitory peptide.

Vasodilatation des vaisseaux isolés et l&#39;isolement de la matrice extracellulaire de souris Tight-peau

The interferon regulatory factor 5 (IRF5) is crucial for cells to determine if they respond in a pro-inflammatory or anti-inflammatory fashion. IRF5's ...

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

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

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

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

Une plate-forme haut débit pour la détection de Salmonella spp /Shigella spp.

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

Arbovirus Infections As Screening Tools for the Identification of Viral Immunomodulators and Host Antiviral Factors

RNA interference- and genome editing-based screening platforms have been widely used to identify host cell factors that restrict virus replication. However, these screens are typically conducted in cells that are naturally permissive to the viral pathogen under study. Therefore, the robust replication of viruses in control conditions may limit the dynamic range of these screens. Furthermore, these screens may be unable to easily identify cellular defense pathways that restrict virus replication if the virus is well-adapted to the host and capable of countering antiviral defenses. In this article, we describe a new paradigm for exploring virus-host interactions through the use of screens that center on naturally abortive infections by arboviruses such as vesicular stomatitis virus (VSV). Despite the ability of VSV to replicate in a wide range of dipteran insect and mammalian hosts, VSV undergoes a post-entry, abortive infection in a variety of cell lines derived from lepidopteran insects, such as the gypsy moth (Lymantria dispar). However, these abortive VSV infections can be &#34;rescued&#34; when host cell antiviral defenses are compromised. We describe how VSV strains encoding convenient reporter genes and restrictive L. dispar cell lines can be paired to set-up screens to identify host factors involved in arbovirus restriction. Furthermore, we also show the utility of these screening tools in the identification of virally encoded factors that rescue VSV replication during coinfection or through ectopic expression, including those encoded by mammalian viruses. The natural restriction of VSV replication in L. dispar cells provides a high signal-to-noise ratio when screening for the conditions that promote VSV rescue, thus enabling the use of simplistic luminescence- and fluorescence-based assays to monitor the changes in VSV replication. These methodologies are valuable for understanding the interplay between host antiviral responses and viral immune evasion factors.

Here, we present the protocols to identify 1) virus-encoded immunomodulators that promote arbovirus replication and 2) eukaryotic host factors that restrict arbovirus replication. These fluorescence- and luminescence-based methods allow researchers to rapidly obtain quantitative readouts of arbovirus replication in simplistic assays with low signal-to-noise ratios.

Arbovirus Infections comme outils de dépistage pour l’Identification des virales facteurs antiviraux immunomodulateurs et hôte

RNA interference- and genome editing-based screening platforms have been widely used to identify host cell factors that restrict virus replication. ...

Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries

The T-cell receptor (TCR) signaling pathway comprises a multitude of mediators that transmit signals upon the activation of the TCR. Different strategies have been proposed and implemented for the identification of new mediators of TCR signaling, which would improve the understanding of T-cell processes, including activation and thymic selection. We describe a screening assay that enables the identification of molecules that influence TCR signaling based on the activation of developing thymocytes. Strong TCR signals cause developing thymocytes to activate apoptotic machinery in a process known as negative selection. Through the application of kinase inhibitors, those with targets that affect TCR signaling are able to override the process of negative selection. The method detailed in this paper can be used to identify inhibitors of canonical kinases with established roles in the TCR signaling pathways and also inhibitors of new kinases yet to be established in the TCR signaling pathways. The screening strategy here can be applied to screens of higher throughput for the identification of novel druggable targets in TCR signaling.

Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries

This paper uses a flow-cytometry-based assay to screen libraries of chemical inhibitors for the identification of inhibitors and their targets that influence T-cell receptor signaling. The methods described here can also be expanded for high-throughput screenings.

Identification des médiateurs du récepteur des cellules T signalisation via la projection des bibliothèques inhibiteur chimique

The T-cell receptor (TCR) signaling pathway comprises a multitude of mediators that transmit signals upon the activation of the TCR. Different strategies ...

Assessment of Acute Wound Healing using the Dorsal Subcutaneous Polyvinyl Alcohol Sponge Implantation and Excisional Tail Skin Wound Models.

Wound healing is a complex process that requires the orderly progression of inflammation, granulation tissue formation, fibrosis, and resolution. Murine models provide valuable mechanistic insight into these processes; however, no single model fully addresses all aspects of the wound healing response. Instead, it is ideal to use multiple models to address the different aspects of wound healing. Here, two different methods that address diverse aspects of the wound healing response are described. In the first model, polyvinyl alcohol sponges are subcutaneously implanted along the mouse dorsum. Following sponge retrieval, cells can be isolated by mechanical disruption, and fluids can be extracted by centrifugation, thus allowing for a detailed characterization of cellular and cytokine responses in the acute wound environment. A limitation of this model is the inability to assess the rate of wound closure. For this, a tail skin excision model is utilized. In this model, a 10 mm x 3 mm rectangular piece of tail skin is excised along the dorsal surface, near the base of the tail. This model can be easily photographed for planimetric analysis to determine healing rates and can be excised for histological analysis. Both described methods can be utilized in genetically altered mouse strains, or in conjunction with models of comorbid conditions, such as diabetes, aging, or secondary infection, in order to elucidate wound healing mechanisms.

Here, two murine wound healing models are described, one designed to assess cellular and cytokine wound healing responses and the other to quantify the rate of wound closure. These methods can be used with complex disease models such as diabetes to determine mechanisms of various aspects of poor wound healing.

Évaluation de la guérison aigue des plaies à l’aide de l’implantation d’éponge d’alcool polyvinyl subcutanée et des modèles excisionaux de blessure de peau de queue.

Wound healing is a complex process that requires the orderly progression of inflammation, granulation tissue formation, fibrosis, and resolution. Murine ...