מחקר זה נתמך על ידי תרומות של הוועדה למחקר באוניברסיטת Antioquia (CODI), המכון הקולומביאני לפיתוח המדע והטכנולוגיה - COLCIENCIAS והמרכז פיתוח מוצרים נגד מחלות טרופיות - 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>

אין ניגוד עניינים הצהיר.

Leishmaniasis עורית היא אנדמית באזורים הטרופיים neotropics. הוא המכונה לעתים קרובות קבוצה של מחלות בגלל קשת מגוונת של ביטויים קליניים, אשר נע בין גושים קטנים עורית להרס הרקמה הרירית ברוטו. סמים זמינים ביותר הם יקרים, דורשים משטרי הטיפול ארוכים נעשים יעילים יותר ויותר, דבר המחיי?...

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> שם מגיב </td><td> סוג </td><td> חברה </td><td> מספר קטלוגי </td></tr><tr><td> קטמין </td><td> מגיב </td><td> הולידיי סקוט-SA </td><td></td></tr><tr><td> Xilacine </td><td> מגיב </td><td> סינתזה </td><td></td></tr><tr><td> PBS </td><td> מגיב </td><td> GIBCO </td><td> 14190-136 </td></tr><tr><td> קליפר דיגיטלי </td><td> ציוד </td><td> דיג </td><td> 15-077-958 </td></tr><tr><td> Giemsa </td><td> מגיב </td><td> SIGMA </td><td> GS1L-1 ליטר </td></tr><tr><td> פורמלין </td><td> מגיב </td><td> נובה במעבדה </td><td> 11273 </td></tr><tr><td> פרפין </td><td> מגיב </td><td> Pechiney אריזות פלסטיק </td><td> PM-996 </td></tr><tr><td> Haemotoxilin </td><td> מגיב </td><td> נובה במעבדה </td><td&gt; 10870103 </td></tr><tr><td> Eosin </td><td></td><td> נובה במעבדה </td><td> 10870203 </td></tr><tr><td> קודאק Ektachem יבש כימיה </td><td> ציוד </td><td> קודאק Ektachem </td><td> DT-60 </td></tr><tr><td> meglumine antimoniate </td><td> מגיב </td><td> אוונטיס </td><td></td></tr><tr><td> מיקרוסקופיה </td><td> ציוד </td><td> ניקון </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

באופן מסורתי, הם אוגרים מחוסן באופן ניסיוני באף או שודד דרכים. עם זאת באתרים אלה כיב לא תמיד מתרחשת, מדידה של גודל הנגע הוא הליך קשה בבעלי חיים מראים קושי לאכול, לנשום ולנוע בגלל הנגע. על מנת לייעל את המודל אוגר עבור leishmaniasis עורית, זכר בוגר צעיר אוגרים זהובים נקבות (Mesocricetus auratus) הוזרקו intradermally עם 1 עד 1.5 x L0 7 promastigotes של מינים לישמניה ההתקדמות של נגעים הבאים על עור הגב הוערכו עד 16 שבועות זיהום הודעה. האוגר הזהוב נבחרה משום שהיא נחשבת הולמת ביו מודל להערכת תרופות נגד שושנת יריחו כאשר הם חשופים לסכנת הדבקה על ידי זנים שונים. דלקת עורית של תוצאות אוגרים ב נגעים כרוניים אך מבוקרת, לבין התפתחות קלינית עם סימנים דומים לאלה שנצפו אצל בני אדם. לכן, הקמת oו היקף הזיהום על ידי מדידת גודל הנגע פי בתחום indurations וכיבים אינו ריאלי. גישה זו הוכיחה צדדיות שלה וניהול קל במהלך חיסון, מעקב ואפיון של נגעים אופיינית (אולקוס), יישום של טיפולים באמצעות דרכים שונות וקבלת דגימות קליניות לאחר טיפולים שונים. באמצעות שיטה זו את איכות החיים של בעלי חיים על תנועה, בחיפוש אחר מזון ומים, משחקים ופעילויות חברתיות isalso משומרים.

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

אופטימיזציה של מודל ניסיוני אוגר leishmaniasis עורית על ידי הזרקה של intradermal<em&gt; שושנת יריחו</em&gt; Promastigotes בעור הגב. גישה זו שימושית בעת חיסון, מעקב, אפיון של נגעים, היישום של טיפולים וקבלת דגימות קליניות. , תנועה בחיפוש אחר מזון ומים, פעולות לשחק חברתית נשמרים.

Leishmaniasis עורית בעור הגב של אוגרים: מודל שימושי להקרנה של תרופות Antileishmanial

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

21.9K Views.  University of Antioquia. אופטימיזציה של מודל ניסיוני אוגר leishmaniasis עורית על ידי הזרקה של intradermal שושנת יריחו Promastigotes בעור הגב. גישה זו שימושית בעת חיסון, מעקב, אפיון של נגעים, היישום של טיפולים וקבלת דגימות קליניות. , תנועה בחיפוש אחר מזון ומים, פעולות לשחק חברתית נשמרים.

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

In vivo Imaging of Transgenic Leishmania Parasites in a Live Host

Distinct species of Leishmania, a protozoan parasite of the family Trypanosomatidae, typically cause different human disease manifestations. The most common forms of disease are visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). Mouse models of leishmaniasis are widely used, but quantification of parasite burdens during murine disease requires mice to be euthanized at various times after infection. Parasite loads are then measured either by microscopy, limiting dilution assay, or qPCR amplification of parasite DNA. The in vivo imaging system (IVIS) has an integrated software package that allows the detection of a bioluminescent signal associated with cells in living organisms. Both to minimize animal usage and to follow infection longitudinally in individuals, in vivo models for imaging Leishmania spp. causing VL or CL were established. Parasites were engineered to express luciferase, and these were introduced into mice either intradermally or intravenously. Quantitative measurements of the luciferase driving bioluminescence of the transgenic Leishmania parasites within the mouse were made using IVIS. Individual mice can be imaged multiple times during longitudinal studies, allowing us to assess the inter-animal variation in the initial experimental parasite inocula, and to assess the multiplication of parasites in mouse tissues. Parasites are detected with high sensitivity in cutaneous locations. Although it is very likely that the signal (photons/second/parasite) is lower in deeper visceral organs than the skin, but quantitative comparisons of signals in superficial versus deep sites have not been done. It is possible that parasite numbers between body sites cannot be directly compared, although parasite loads in the same tissues can be compared between mice. Examples of one visceralizing species (L. infantum chagasi) and one species causing cutaneous leishmaniasis (L. mexicana) are shown. The IVIS procedure can be used for monitoring and analyzing small animal models of a wide variety of Leishmania species causing the different forms of human leishmaniasis.

In vivo Imaging of Transgenic Leishmania Parasites in a Live Host

An in vivo imaging system is used to generate quantitative measurements of murine infection with the Trypanosomatid protozoan Leishmania. This is a non-invasive and non-lethal method for detecting parasites expressing luciferase within many tissues throughout the course of chronic Leishmania spp. infection.

בתחום ההדמיה vivo של טפילים טראנסגנטי שושנת יריחו שורה חיים

Distinct species of Leishmania, a protozoan parasite of the family Trypanosomatidae, typically cause different human disease manifestations. The most ...

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.

אינדוקציה של מחלת שתל נגד מארח ו<em&gt; In Vivo</em&gt; ניטור תא T תוך שימוש במודל Murine MHC התאמה

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 ...

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.

Assay הצלה וטרנספורמציה טפילה להקרנת Antileishmanial נגד תאי<em&gt; ישמניה donovani</em&gt; Amastigotes בקו THP1 אדם חריף Monocytic וקמיה של תאים

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.

שיטת הקרנה חדשה לאבולוציה המכוונת של אנזימי Bacteriolytic Thermostable

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.

הקרנת גנטיקה קדימה VIGS בתיווך לזיהוי גני המעורבים בהתנגדות Nonhost


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

Development of Leishmania Species Strains with Constitutive Expression of eGFP

Protozoan parasites of the genus Leishmania cause leishmaniasis, a disease with variable clinical manifestations that affects millions of people worldwide. Infection with L. donovani can result in fatal visceral disease. In Panama, Colombia, and Costa Rica, L. panamensis is responsible for most of the reported cases of cutaneous and mucocutaneous leishmaniasis. Studying a large number of drug candidates with the methodologies available to date is quite difficult, given that they are very laborious for evaluating the activity of compounds against intracellular forms of the parasite or for performing in vivo assays. In this work, we describe the generation of L. panamensis and L. donovani strains with constitutive expression of the gene that encodes for an enhanced green fluorescent protein (eGFP) integrated into the locus that encodes for 18S rRNA (ssu). The gene encoding eGFP was obtained from a commercial vector and amplified by polymerase chain reaction (PCR) to enrich it and add restriction sites for the BglII and KpnI enzymes. The eGFP amplicon was isolated by agarose gel purification, digested with the enzymes BglII and KpnI, and ligated into the Leishmania expression vector pLEXSY-sat2.1 previously digested with the same set of enzymes. The expression vector with the cloned gene was propagated in E. coli, purified, and the presence of the insert was verified by colony PCR. The purified plasmid was linearized and used to transfect L. donovani and L. panamensis parasites. The integration of the gene was verified by PCR. The expression of the eGFP gene was evaluated by flow cytometry. Fluorescent parasites were cloned by limiting dilution, and clones with the highest fluorescence intensity were selected using flow cytometry.

Development of Leishmania Species Strains with Constitutive Expression of eGFP

Here, we describe the methodology used for generating L. panamensis and L. donovani strains expressing the gene for eGFP as a stable integrated transgene using the pLEXSY system. Transfected parasites were cloned by limiting dilution, and clones with the highest fluorescence intensity in both species were selected for further use in drug screening assays.

התפתחות זני לישמניה עם ביטוי מכונן של eGFP

Protozoan parasites of the genus Leishmania cause leishmaniasis, a disease with variable clinical manifestations that affects millions of people ...

Genetics

Intravital Microscopy Imaging of the Liver following Leishmania Infection: An Assessment of Hepatic Hemodynamics

Intravital microscopy (IVM) is a powerful optical imaging technique that has made possible the visualization, monitoring and quantification of various biological events in real time and in live animals. This technology has greatly advanced our understanding of physiological processes and pathogen-mediated phenomena in specific organs.
In this study, IVM is applied to the mouse liver and protocols are designed to image in vivo the circulatory system of the liver and measure red blood cell (RBC) velocity in individual hepatic vessels. To visualize the different vessel subtypes that characterize the hepatic organ and perform blood flow speed measurements, C57Bl/6 mice are intravenously injected with a fluorescent plasma reagent that labels the liver-associated vasculature. IVM enables in vivo, real time, measurement of RBC velocity in a specific vessel of interest. Establishing this methodology will make it possible to investigate liver hemodynamics under physiological and pathological conditions. Ultimately, this imaging-based methodology will be important for studying the influence of L. donovani infection&#160;on hepatic hemodynamics.
This method can be applied to other infectious models and mouse organs and might be further extended to pre-clinical testing of a drug&#8217;s effect on inflammation by quantifying its effect on blood flow.

Intravital Microscopy Imaging of the Liver following Leishmania Infection: An Assessment of Hepatic Hemodynamics

This article reports on a detailed method for the dynamic measurement and quantification of blood flow velocity within individual blood vessels of the mouse liver vasculature using intravital microscopy imaging in combination with a specific methodology for image acquisition and analysis.

מיקרוסקופית Intravital הדמיה של הכבד הבא<em&gt; שושנת יריחו</em&gt; זיהום: הערכה של פרמטרים המודינמיים בדיה

Intravital microscopy (IVM) is a powerful optical imaging technique that has made possible the visualization, monitoring and quantification of various ...

In Vivo Infection with Leishmania amazonensis to Evaluate Parasite Virulence in Mice

Leishmania spp. are protozoan parasites that cause leishmaniases, diseases that present a wide spectrum of clinical manifestations from cutaneous to visceral lesions. Currently, 12 million people are estimated to be infected with Leishmania worldwide and over 1 billion people live at the risk of infection. Leishmania amazonensis is endemic in Central and South America and usually leads to the cutaneous form of the disease, which can be directly visualized in an animal model. Therefore, L. amazonensis strains are good models for cutaneous leishmaniasis studies because they are also easily cultivated in vitro. C57BL/6 mice mimic the L. amazonensis-driven disease progression observed in humans and are considered one of the best mice strains model for cutaneous leishmaniasis. In the vertebrate host, these parasites inhabit macrophages despite the defense mechanisms of these cells. Several studies use in vitro macrophage infection assays to evaluate the parasite infectivity under different conditions. However, the in vitro approach is limited to an isolated cell system that disregards the organism&#39;s response. Here, we compile an in vivo murine infection method that provides a systemic physiological overview of the host-parasite interaction. The detailed protocol for the in vivo infection of C57BL/6 mice with L. amazonensis comprises parasite differentiation into infective amastigotes, mice footpad cutaneous inoculation, lesion development, and parasite load determination. We propose this well-established method as the most adequate method for physiological studies of the host immune and metabolic responses to cutaneous leishmaniasis.

In Vivo Infection with Leishmania amazonensis to Evaluate Parasite Virulence in Mice

Here, we present a compiled protocol to evaluate the cutaneous infection of mice with Leishmania amazonensis. This is a reliable method for studying parasite virulence, allowing a systemic view of the vertebrate host response to the infection.

ב Vivo זיהום עם לישמניה מלכותית כדי להעריך טפיל התקפה אלימה בעכברים

Leishmania spp. are protozoan parasites that cause leishmaniases, diseases that present a wide spectrum of clinical manifestations from cutaneous to ...

Cell Migration and Cell Adhesion Assays to Investigate Leishmania-Host Cell Interaction

Leishmania is an intracellular protozoan parasite that causes a broad spectrum of clinical manifestations, ranging from self-resolving localized cutaneous lesions to a highly fatal visceral form of the disease. An estimated 12 million people worldwide are currently infected, and another 350 million face risk of infection. It is known that host cells infected by Leishmania parasites, such as macrophages or dendritic cells, can migrate to different host tissues, yet how migration contributes to parasite dissemination and homing remains poorly understood. Therefore, assessing these parasites' ability to modulate host cell response, adhesion, and migration will shed light on mechanisms involved in disease dissemination and visceralization. Cellular migration is a complex process in which cells undergo polarization and protrusion, allowing them to migrate. This process, regulated by actin and tubulin-based microtubule dynamics, involves different factors, including the modulation of cellular adhesion to the substrate. Cellular adhesion and migration processes have been investigated using several models. Here, we describe a method to characterize the migratory aspects of host cells during Leishmania infection. This detailed protocol presents the differentiation and infection of dendritic cells, the analysis of host cell motility and migration, and the formation of adhesion complexes and actin dynamics. This in vitro protocol aims to further elucidate mechanisms involved in Leishmania dissemination within vertebrate host tissues and can also be modified and applied to other cell migration studies.

Cell Migration and Cell Adhesion Assays to Investigate Leishmania-Host Cell Interaction

Here we study implications of Leishmania-host interaction by exploring Leishmania-infected dendritic cells migration. The differentiation and infection of dendritic cells, migration analysis, and the evaluation of adhesion complexes and actin dynamics are described. This method can be applied to other host cell migration studies when infected with Leishmania or other intracellular parasite species.

Leishmania is an intracellular protozoan parasite that causes a broad spectrum of clinical manifestations, ranging from self-resolving localized cutaneous ...

In Vivo Imaging of Leishmania infantum-infected Hamsters by Gingival Inoculation of Axenic Amastigotes Expressing Luciferase

American tegumentary leishmaniasis (ATL) and visceral leishmaniasis (VL) are considered neglected by the World Health Organization. VL can be lethal if not treated; the drugs used in treatment are toxic, and there are cases of resistance. Preclinical tests can represent a bottleneck in discovering new medicines for treatment, depending on the animal model, the strain used, and the inoculum route. The golden hamster stands out for its high susceptibility to subgenera Viannia and Leishmania species, displaying many of the clinical and immunopathological processes observed in human disease.
By hamster anatomy, which has a short tail and limbs, the intracardiac route is usually the choice for intravenous injection of Leishmania. However, it is an inoculum that can lead to bleeding and eventually to animal death. Thus, we standardized an alternative intravenous inoculation route for infection at the gingival vein, which is minimally invasive, allows easy venous access, and causes few local and systemic injuries to the animal. Therefore, hamsters infected by the intraperitoneal (IP) or intragingival (IG) route with Leishmania Infantum expressing luciferase (Luc) were followed up for 22 days by the bioluminescence imaging system and 50 days and 8 months post infection by PCR.
After gingival inoculation of both axenic amastigotes and promastigotes of L. infantum-Luc, bioluminescence was restricted for at least 2 weeks at the site of injection, which is an indicator of infection in the tissues around the gingival plexus. Hamsters infected intraperitoneally with L. infantum-Luc displayed bioluminescence dispersed throughout the abdomen, as expected. However, by the bioluminescence imaging system infection declined until the 50th dpi and was only detectable by PCR.&#160;Axenic amastigotes showed better infection than promastigotes, as evaluated by PCR. Indeed, 8 months after infection, parasites were detected by PCR in the liver of animals inoculated with axenic amastigotes by the intravenous route, which can be a characteristic of the reference strain of L. infantum MHOM/BR/1974/PP75, whose infection progresses slowly and display low parasite burden, below the bioluminescent imaging resolution. Thus, axenic amastigotes can be a better choice for infection and follow-up than promastigotes, and the gingival inoculum is a feasible route for intravenous injection of Leishmania and other pathogens.

Here we present a longitudinal evaluation of golden hamsters infected intraperitoneally (IP) or via intragingival (IG) with L. infantum-Luc by bioluminescent imaging and by PCR. Hamsters were evaluated 1 day post infection (1 dpi), 1 week after infection (8 dpi), and 3 weeks after infection (22 dpi) and euthanized at the 50th dpi and 8 months post infection.

ב Vivo הדמיה של אוגרים נגועים בלישמניה אינפנטום על ידי חיסון חניכיים של אמסטיגוטים אקסניים המבטאים לוציפראז

American tegumentary leishmaniasis (ATL) and visceral leishmaniasis (VL) are considered neglected by the World Health Organization. VL can be lethal if ...

Leishmaniasis עורית בעור הגב של אוגרים: מודל שימושי להקרנה של תרופות Antileishmanial

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בתחום ההדמיה vivo של טפילים טראנסגנטי שושנת יריחו שורה חיים

אינדוקציה של מחלת שתל נגד מארח ו

Assay הצלה וטרנספורמציה טפילה להקרנת Antileishmanial נגד תאי

שיטת הקרנה חדשה לאבולוציה המכוונת של אנזימי Bacteriolytic Thermostable

הקרנת גנטיקה קדימה VIGS בתיווך לזיהוי גני המעורבים בהתנגדות Nonhost

התפתחות זני לישמניה עם ביטוי מכונן של eGFP

מיקרוסקופית Intravital הדמיה של הכבד הבא

ב Vivo זיהום עם לישמניה מלכותית כדי להעריך טפיל התקפה אלימה בעכברים

Cell Migration and Cell Adhesion Assays to Investigate Leishmania-Host Cell Interaction

ב Vivo הדמיה של אוגרים נגועים בלישמניה אינפנטום על ידי חיסון חניכיים של אמסטיגוטים אקסניים המבטאים לוציפראז