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Hypoxia-inducible factor-1 alpha (HIF-1α) is one of the master regulators of immune and metabolic cellular functions. HIF-1α, a transcriptional factor whose activity is closely related to oxygen levels, is a target for understanding infectious disease control. Several studies have demonstrated that HIF-1α plays an important role during the infectious process, while its role in relation to parasite virulence has not been addressed. In this work, we studied the expression levels of HIF-1α and related angiogenic vascular endothelial growth factor A (VEGF-A) in human macrophages infected with promastigotes of hypo- or hyper-virulent Leishmania major human isolates. L. major parasites readily subverted host macrophage functions for their survival and induced local oxygen consumption at the site of infection. In contrast to hypo-virulent parasites that induce high HIF-1α expression levels, hyper-virulent L. major reduced HIF-1α expression in macrophages under normoxic or hypoxic conditions, and consequently impeded the expression of VEGF-A mRNA. HIF-1α may play a key role during control of disease chronicity, severity, or outcome.
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Leishmania major , Leishmaniasis , Parásitos , Animales , Humanos , Factor A de Crecimiento Endotelial Vascular , Virulencia , Macrófagos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Hipoxia/metabolismoRESUMEN
In human cutaneous leishmaniasis (HCL) caused by Leishmania (L.) major, the cutaneous lesions heal spontaneously and induce a Th1-type immunity that confers solid protection against reinfection. The same holds true for the experimental leishmaniasis induced by L. major in C57BL/6 mice where residual parasites persist after spontaneous clinical cure and induce sustainable memory immune responses and resistance to reinfection. Whether residual parasites also persist in scars of cured HCL caused by L. major is still unknown. Cutaneous scars from 53 volunteers with healed HCL caused by L. major were biopsied and the tissue sample homogenates were analyzed for residual parasites by four methods: i) microscope detection of amastigotes, ii) parasite culture by inoculation on biphasic medium, iii) inoculation of tissue exctracts to the footpad of BALB/c mice, an inbred strain highly susceptible to L. major, and iv) amplification of parasite kDNA by a highly sensitive real-time PCR (RT-PCR). Our results show that the scars of healed lesions of HCL caused by L. major do not contain detectable residual parasites, suggesting that this form likely induces a sterile cure at least within the scars. This feature contrasts with other Leishmania species causing chronic, diffuse, or recidivating forms of leishmaniasis where parasites do persist in healed lesions. The possibility that alternative mechanisms to parasite persistence are needed to boost and maintain long-term immunity to L. major, should be taken into consideration in vaccine development against L. major infection.
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Leishmania major , Leishmaniasis Cutánea , Parásitos , Animales , Cicatriz , Progresión de la Enfermedad , Humanos , Ratones , Ratones Endogámicos C57BL , ReinfecciónRESUMEN
This study shows, for the first time, natural Leishmania infection among Jaculus spp. in an endemic region of Tataouine, South Tunisia. To better characterize the transmission cycles in this complex focus of mixed transmission, Leishmania detection and species identification were performed by direct examination, internal transcribed spacer-1 (ITS1)-PCR-restriction fragment length polymorphism (RFLP), and sequencing of Jaculus (J.) jaculus (Linnaeus, 1758) and J. hirtipes (Lichtenstein, 1823) rodent species, which are frequently encountered in this area. Leishmania parasites were observed in 19 (41.3%) smears, while DNA parasites were detected in 28 (60.9%) Jaculus spp. spleens; among them, 12 (54.5%) were from 22 J. jaculus individuals and 16 (66.7%) were from 24 J. hirtipes individuals. Leishmania parasites were confirmed as Leishmania (L.) killicki (syn. L. tropica) in two J. hirtipes individuals (4.3%) and L. major (n = 24; 52.2%) in 10 J. jaculus and 14 J. hirtipes individuals. This finding represents the first evidence of natural infection with Leishmania parasites in rodents belonging to the Jaculus genus, providing the rationale to consider them as potential reservoir hosts of Old World Leishmania parasites in Tunisia and North Africa.
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The clinical expression of zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania (L.) major parasites has a broad spectrum ranging from asymptomatic infection to self-limited cutaneous sores or severe disease. In concert with the host immune responses, the vector variability and the number of bites, genetic variation between L. major isolates might impact on the clinical output of the disease. We investigated herein the intra-specific variability of L. major field isolates independently of host or vector factors and then tried to correlate parasite variability to ZCL severity in corresponding patients. Several assays were applied, i.e., in vivo pathogenicity of promastigotes in a BALB/c mice model, resistance/sensibility to complement lysis, in vitro growth kinetics, and expression of different lectins on the promastigote surface. Combining all these parameters allowed us to conclude that the resistance to complement lysis and PNA/Jacalin lectins binding to parasite surfaces are important markers of parasite virulence. These factors correlate significantly with clinic polymorphism of ZCL and modestly with genetic micro-heterogeneity, a characteristic we previously revealed with a MLMT profile.
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AIMS: Molecular characterization of extended-spectrum ß-lactamases (ESBLs) among Salmonella Kentucky and Typhimurium isolates: partial sequence analysis of the types of ß-lactamases found in these isolates, clonality, resistance and supposed emergence of ESBL-producing strains. METHODS AND RESULTS: A retrospective study surveyed the ESBLs occurring in a total of 1404 Salmonella Kentucky and Typhimurium isolates collected over a 5-year period in Tunisia. Antimicrobial susceptibility tests, ESBL phenotype determination (double-disc synergy) were performed. Polymerase chain reaction assays were used for the detection of ß-lactamase genes (blaTEM , blaSHV , blaOXA-1 and blaCTX-M ), class 1 and class 2 integrases (intI1 and intI2) and the 3' conserved segment (3'-CS) of class 1 integron (qacEΔ1+sul1). Sequencing of amplicons of ß-lactamase genes was performed. Percentage of 9.8 of the isolates (S. Kentucky = 117, S. Typhimurium = 20) were either resistant to penicillin and had decreased susceptibility to cefotaxime or had a positive double-disc synergy test result. Polymerase chain reaction detected that these isolates harboured one or more ß-lactamase genes (blaTEM , blaSHV , blaOXA-1 or blaCTX-M ). TEM-1, TEM-34, CTX-M15, CTX-M9 and CTX-M61 type ESBLs were identified through sequencing. The novel Salmonella cefotaxime-hydrolysing ß-lactamase, CTX-M61/TEM-34, detected in this study showed the emergence of new CTX-M-type ESBLs in Tunisia. There were found 33 different multidrug resistance (MDR) patterns. CONCLUSION: These findings highlighted the proliferation of ESBLs and MDR in Salmonella Kentucky and Typhimurium isolates from numerous regions and sources in Tunisia, indicating an emerging public health concern. SIGNIFICANCE AND IMPACT OF THE STUDY: For the first time CTX-M-61/TEM-34, a novel cefotaxime-hydrolysing ß-lactamase of Salmonella had been detected.
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Salmonella enterica , beta-Lactamasas , Antibacterianos/farmacología , Cefotaxima/farmacología , Kentucky , Estudios Retrospectivos , Salmonella , Salmonella enterica/genética , Serogrupo , Túnez , beta-Lactamasas/genéticaRESUMEN
Quality and food safety represent a major stake and growing societal challenge in the world. Bacterial contamination of food and water resources is an element that pushes scientists to develop new means for the rapid and efficient detection and identification of these pathogens. Conventional detection tools are often bulky, laborious, expensive to buy, and, above all, require an analysis time of a few hours to several days. The interest in developing new, simple, rapid, and nonlaborious bacteriological diagnostic methods is therefore increasingly important for scientists, industry, and regulatory bodies. In this study, antibiotic-functionalized metallic nanoparticles were used to isolate and identify the foodborne bacterial strains Bacillus cereus and Shigella flexneri. With this aim, a new diagnostic tool for the rapid detection of foodborne pathogenic bacteria, gold nanoparticle-based centri-chronoamperometry, has been developed. Vancomycin was first stabilized at the surface of gold nanoparticles and then incubated with the bacteria B. cereus or S. flexneri to form the AuNP@vancomycin/bacteria complex. This complex was separated by centrifugation, then treated with hydrochloric acid and placed at the surface of a carbon microelectrode. The gold nanoparticles of the formed complex catalyzed the hydrogen reduction reaction, and the generated current was used as an analytical signal. Our results show the possibility of the simple and rapid detection of the S. flexneri and B. cereus strains at very low numbers of 3 cells/mL and 12 cells/mL, respectively. On the other hand, vancomycin-capped magnetic beads were easily synthesized and then used to separate the bacteria from the culture medium. The results show that vancomycin at the surface of these metallic nanoparticles is able to interact with the bacteria membrane and then used to separate the bacteria and to purify an inoculated medium.
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Antibacterianos/química , Microbiología de Alimentos , Nanopartículas del Metal/química , Animales , Bacillus cereus , Oro , Separación Inmunomagnética , Fenómenos Magnéticos , MagnetismoRESUMEN
BACKGROUND: Leishmanin Skin Test (LST) is considered as a useful indicator of past infection by Leishmania parasites. However, the temporal dynamics of a positive LST under different epidemiologic scenarios and whether it relates to the protection against the recurrence of an overt disease are not fully documented. METHODOLOGY/PRINCIPAL FINDINGS: We report here on a population based prospective study conducted on 2686 individuals living in two foci located in Central Tunisia, to assess over a one-year epidemiologic season, the incidence of Leishmania (L.) major infection and disease and changes in LST reactivity. The two foci were both endemic for Cutaneous Leishmaniasis (CL) due to L. major, but contrasted in their history for this disease (ie: an old focus versus a recent focus). We found that most infections occurred in the new focus (290/1000; 95% CI: 265-315 person-years) with an incidence rate of CL lesions 2.4 times higher than in the old focus. Likewise, the rates of LST reactivity reversion and loss, in the new focus, were 99/1000[38-116] person-years and 14/1000[8-21] person-years, respectively. Loss of LST reactivity was not noticed in the old focus. Interestingly, the incidence rates of symptomatic infection did not differ significantly according to the LST status at enrolment (negative versus positive) between the combined foci and the new one. CONCLUSIONS/SIGNIFICANCE: Our findings confirm LST as a good tool for assessing L. major cryptic infection. However, the instability of the LST positivity in new foci should be considered as an important confounder of the outcome of this infection when developing a research protocol for vaccine trial.
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Leishmania major/inmunología , Leishmaniasis Cutánea/epidemiología , Leishmaniasis Cutánea/inmunología , Pruebas Cutáneas/métodos , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Incidencia , Leishmaniasis Cutánea/parasitología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Túnez/epidemiología , Adulto JovenRESUMEN
Sensitive and reliable approaches targeting the detection of Leishmania are critical for effective early diagnosis and treatment of leishmaniasis. In this frame, this paper describes a rapid quantification assay to detect Leishmania parasites based on the combination of the electrocatalytic ability of gold nanoparticles (AuNPs) to act as a catalyst for the hydrogen formation reaction along with the specificity of the interaction between casein and the major surface protease of the Leishmania parasite, GP63. First, pure and casein-modified AuNPs were prepared and characterized by scanning electron microscopy and ultraviolet-visible spectroscopy. Then, casein-conjugated AuNPs were incubated with Leishsmania parasites in solution; the formed complex was collected by centrifugation, treated by acidic solution, and the pelleted AuNPs were placed on screen-printed carbon electrodes (SPCEs) and chronoamperometric measurements were carried out. Our results suggest that it is possible to detect Leishmania parasites, with a limit less than 1 parasite/mL. A linear response over a wide concentration interval, ranging from 2 × 10-2 to 2 × 105 parasites/mL, was achieved. Additionally, a pretreatment of Leishmania parasites with Amphotericin B, diminished their interaction with casein. This findings and methodology are very useful for drug efficacy assessment.
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Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Nanopartículas del Metal/química , Metaloendopeptidasas/análisis , Caseínas/química , Oro/química , Leishmania/enzimología , Leishmania/aislamiento & purificaciónRESUMEN
Genome data, with underlying new knowledge, are accumulating at exponential rate thanks to ever-improving sequencing technologies and the parallel development of dedicated efficient Bioinformatics methods and tools. Advanced Education in Bioinformatics and Genome Analyses is to a large extent not accessible to students in developing countries where endeavors to set up Bioinformatics courses concern most often only basic levels. Here, we report a pioneering pilot experience concerning the design and implementation, from scratch, of a three-months advanced and extensive course in Bioinformatics and Genome Analyses in the Institut Pasteur de Tunis. Most significantly the outcome of the course was upgrading the participants' skills in Bioinformatics and Genome Analyses to recognized international standards. Here we detail the different steps involved in the implementation of this course as well as the topics covered in the program. The description of this pilot experience might be helpful for the implementation of other similar educational projects, notably in developing countries, aiming to go beyond basics and providing young researchers with high-level skills.
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Biología Computacional/educación , Curriculum , Modelos Educacionales , Academias e Institutos , Países en Desarrollo , Humanos , Estudiantes , TúnezRESUMEN
Background: Human echinococcosis is a neglected infectious disease affecting more than 1 million people globally. Its diagnosis is expensive and difficult because of lack of adequate resources in low-resource locations, where most cases occur. Methods: A group of volunteers diagnosed with the 2 main types of echinococcosis and corresponding control groups were recruited from hospitals in Tunisia (32 patients with cystic echinococcosis and 43 controls) and Poland (16 patients with alveolar echinococcosis and 8 controls). Breath samples were collected from all patients and analyzed by gas chromatography coupled to mass spectrometry, and a specifically developed electronic nose system. Results: The chemical analysis revealed statistically different concentrations of 2 compounds in the breath of patients with cystic echinococcosis compared to controls, and statistically different concentrations of 7 compounds in the breath of patients with alveolar echinococcosis compared to controls. The discrimination accuracy achieved by the electronic nose system was 100% for cystic echinococcosis and 92.9% for alveolar echinococcosis, while the discrimination accuracy between these 2 patient groups was 92.1%. Conclusion: Here we advocate a noninvasive, fast, easy-to-operate and nonexpensive diagnostic tool for the diagnosis of human echinococcosis disease through exhaled breath analysis, suitable for early diagnosis and population screening.
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Pruebas Respiratorias/métodos , Equinococosis/diagnóstico , Técnicas Electroquímicas/métodos , Espiración , Compuestos Orgánicos Volátiles/análisis , Adolescente , Adulto , Animales , Biomarcadores/análisis , Biomarcadores/química , Pruebas Respiratorias/instrumentación , Técnicas Electroquímicas/instrumentación , Nariz Electrónica , Femenino , Helmintiasis/diagnóstico , Helmintos/patogenicidad , Humanos , Masculino , Espectrometría de Masas , Persona de Mediana Edad , Técnicas de Diagnóstico Molecular , Polonia , Túnez , Adulto JovenRESUMEN
Human cutaneous leishmaniasis, although designated as one of the most neglected tropical diseases, remains underestimated due to its misdiagnosis. The diagnosis is mainly based on the microscopic detection of amastigote forms, isolation of the parasite, or the detection of Leishmania DNA, in addition to its differential clinical characterization; these tools are not always available in routine daily practice, and they are expensive and time-consuming. Here, we present a simple-to-use, noninvasive approach for human cutaneous leishmaniasis diagnosis, which is based on the analysis of volatile organic compounds in exhaled breath with an array of specifically designed chemical gas sensors. The study was realized on a group of n = 28 volunteers diagnosed with human cutaneous leishmaniasis and a group of n = 32 healthy controls, recruited in various sites from Tunisia, an endemic country of the disease. The classification success rate of human cutaneous leishmaniasis patients achieved by our sensors test was 98.2% accuracy, 96.4% sensitivity, and 100% specificity. Remarkably, one of the sensors, based on CuNPs functionalized with 2-mercaptobenzoxazole, yielded 100% accuracy, 100% sensitivity, and 100% specificity for human cutaneous leishmaniasis discrimination. While AuNPs have been the most extensively used in metal nanoparticle-ligand sensing films for breath sensing, our results demonstrate that chemical sensors based on ligand-capped CuNPs also hold great potential for breath volatile organic compounds detection. Additionally, the chemical analysis of the breath samples with gas chromatography coupled to mass spectrometry identified nine putative breath biomarkers for human cutaneous leishmaniasis.
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Pruebas Respiratorias/métodos , Leishmaniasis Cutánea/diagnóstico , Nanopartículas del Metal/química , Compuestos Orgánicos Volátiles/análisis , Adolescente , Adulto , Benzoxazoles/química , Biomarcadores/análisis , Cobre/química , Técnicas Electroquímicas/métodos , Femenino , Cromatografía de Gases y Espectrometría de Masas/métodos , Oro/química , Humanos , Masculino , Persona de Mediana Edad , Platino (Metal)/química , Compuestos de Sulfhidrilo/química , Adulto JovenRESUMEN
Protozoan parasites of the genus Leishmania adapt to environmental change through chromosome and gene copy number variations. Only little is known about external or intrinsic factors that govern Leishmania genomic adaptation. Here, by conducting longitudinal genome analyses of 10 new Leishmania clinical isolates, we uncovered important differences in gene copy number among genetically highly related strains and revealed gain and loss of gene copies as potential drivers of long-term environmental adaptation in the field. In contrast, chromosome rather than gene amplification was associated with short-term environmental adaptation to in vitro culture. Karyotypic solutions were highly reproducible but unique for a given strain, suggesting that chromosome amplification is under positive selection and dependent on species- and strain-specific intrinsic factors. We revealed a progressive increase in read depth towards the chromosome ends for various Leishmania isolates, which may represent a nonclassical mechanism of telomere maintenance that can preserve integrity of chromosome ends during selection for fast in vitro growth. Together our data draw a complex picture of Leishmania genomic adaptation in the field and in culture, which is driven by a combination of intrinsic genetic factors that generate strain-specific phenotypic variations, which are under environmental selection and allow for fitness gain.IMPORTANCE Protozoan parasites of the genus Leishmania cause severe human and veterinary diseases worldwide, termed leishmaniases. A hallmark of Leishmania biology is its capacity to adapt to a variety of unpredictable fluctuations inside its human host, notably pharmacological interventions, thus, causing drug resistance. Here we investigated mechanisms of environmental adaptation using a comparative genomics approach by sequencing 10 new clinical isolates of the L. donovani, L. major, and L. tropica complexes that were sampled across eight distinct geographical regions. Our data provide new evidence that parasites adapt to environmental change in the field and in culture through a combination of chromosome and gene amplification that likely causes phenotypic variation and drives parasite fitness gains in response to environmental constraints. This novel form of gene expression regulation through genomic change compensates for the absence of classical transcriptional control in these early-branching eukaryotes and opens new venues for biomarker discovery.
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Adaptación Fisiológica/genética , Dosificación de Gen , Genoma de Protozoos , Cariotipo , Leishmania donovani/genética , Telómero/genética , Animales , Cromosomas/genética , Cricetinae/parasitología , Variaciones en el Número de Copia de ADN , Perros/parasitología , Evolución Molecular , Amplificación de Genes , Regulación de la Expresión Génica , Genes Protozoarios , Aptitud Genética , Genómica , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Leishmania donovani/crecimiento & desarrollo , Leishmaniasis Visceral/parasitologíaRESUMEN
Experimental models have often been at the origin of immunological paradigms such as the M1/M2 dichotomy following macrophage polarization. However, this clear dichotomy in animal models is not as obvious in humans, and the separating line between M1-like and M2-like macrophages is rather represented by a continuum, where boundaries are still unclear. Indeed, human infectious diseases, are characterized by either a back and forth or often a mixed profile between the pro-inflammatory microenvironment (dominated by interleukin (IL)-1ß, IL-6, IL-12, IL-23 and Tumor Necrosis Factor (TNF)-α cytokines) and tissue injury driven by classically activated macrophages (M1-like) and wound healing driven by alternatively activated macrophages (M2-like) in an anti-inflammatory environment (dominated by IL-10, Transforming growth factor (TGF)-ß, chemokine ligand (CCL)1, CCL2, CCL17, CCL18, and CCL22). This review brews the complexity of the situation during infectious diseases by stressing on this continuum between M1-like and M2-like extremes. We first discuss the basic biology of macrophage polarization, function, and role in the inflammatory process and its resolution. Secondly, we discuss the relevance of the macrophage polarization continuum during infectious and neglected diseases, and the possibility to interfere with such activation states as a promising therapeutic strategy in the treatment of such diseases.
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Diferenciación Celular , Enfermedades Transmisibles/inmunología , Activación de Macrófagos , Macrófagos/inmunología , Citocinas/genética , Citocinas/metabolismo , Humanos , Macrófagos/citologíaRESUMEN
Influenza is a viral infectious disease considered as a source of many health problems and enormous socioeconomic disruptions. Conventional methods are inadequate for in-field detection of the virus and generally suffer from being laborious and time-consuming. Thus, studies aiming to develop effective alternatives to conventional methods are urgently needed. In this work, we developed an approach for the isolation and detection of influenza A virus subtype H9N2. For this aim, two specific influenza receptors were used. The first, anti-matrix protein 2 (M2) antibody, was attached to iron magnetic nanoparticles (MNPs) and used for the isolation of the virus from allantoic fluid. The second biomolecule, Fetuin A, was attached to an electrochemical detectable label, gold nanoparticles (AuNPs), and used to detect the virus tacking advantage from fetuin-hemagglutinin interaction. The MNP-Influenza virus-AuNP formed complex was isolated and treated by an acid solution then the collected gold nanoparticles were deposited onto a screen printed carbon electrode. AuNPs catalyzes the hydrogen ions reduction in acidic medium while applying an appropriate potential, and the generated current signal was proportional to the virus titer. This approach allows the rapid detection of influenza virus A/H9N2 at a less than 16 HAU titer.
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Técnicas Biosensibles/métodos , Carbono/química , Oro/química , Subtipo H9N2 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/diagnóstico , Nanopartículas de Magnetita/química , Animales , Anticuerpos Inmovilizados/química , Catálisis , Pollos/virología , Huevos/virología , Glicoproteínas Hemaglutininas del Virus de la Influenza/análisis , Glicoproteínas Hemaglutininas del Virus de la Influenza/aislamiento & purificación , Inmunoensayo/métodos , Gripe Aviar/virología , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , MicroelectrodosRESUMEN
Leishmaniasis is a parasitic reticuloendotheliosis whose pathogen is a zooflagellate belonging to the genus Leishmania transmitted by the bite of an infected phlebotome. Recently, a unique secretory lipase from the human pathogen Leishmania donovani Ldlip3 has been identified and characterized. This lipase has a high identity with a putative triacylglycerol lipase of Leishmania major (Lmlip2). In the present study, Lmlip2 was expressed in the eukaryotic heterologous expression system Pichia pastoris as tagged enzyme of 308 amino acids. Maximal protein production was reached after 2 days of fermentation. Optimal Lmlip2 lipase activity was measured using the pH stat technique at pH 8â¯at 26⯰C using vinyl esters and triacylglycerols (true lipids) as substrates. Moreover, biochemical characterization of Lmlip2 contained in culture supernatant, illustrates that L. major secreted lipase is active and stable at low temperatures especially 26°and prefer neutral pH; concerning substrate specificityLmlip2 presents a preference for short chains lipid substrates vinyl esters such as VC2, VC3 and VC4 likewise, it is capable to hydrolyze long chain triacylglycerols like olive oil. Metal ions and surfactants tested in this study decrease Lmlip2 activity. Further studies are needed to clarify the relation between the lipase activity and the virulence. Thus, it could lead to the identification of novel targets to block cutaneous Leishmaniasis in human hosts.
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Leishmania major/enzimología , Leishmania major/genética , Lipasa/genética , Lipasa/metabolismo , Pichia/genética , Secuencia de Aminoácidos , Secuencia de Bases , Biocatálisis , Clonación Molecular , Inhibidores Enzimáticos/farmacología , Estabilidad de Enzimas , Expresión Génica , Humanos , Concentración de Iones de Hidrógeno , Lipasa/antagonistas & inhibidores , Lipasa/química , Modelos Moleculares , Conformación Proteica , Alineación de Secuencia , TemperaturaRESUMEN
One portion of the family Paramyxoviridae is a group of Unclassified Morbilli-Related Viruses (UMRV) recently recognized in wild small mammals. At a global level, the evolutionary history of these viruses is not properly understood and the relationships between UMRV and their hosts still remain largely unstudied. The present study revealed, for the first time, that Rodentia associated UMRV emerged from a common ancestor in southern Africa more than 4000 years ago. Sequenced UMRV originating from different regions in the world, clustered into four well-supported viral lineages, which suggest that strain diversification occurred during host dispersal and associated exchanges, with purifying selection pressure as the principal evolutionary force. In addition, multi-introductions on different continents and islands of Rodentia associated UMRV and spillover between rodent species, most probably Rattus rattus, were detected and indicate that these animals are implicated in the vectoring and in the worldwide emergence of this virus group. The natural history and the evolution dynamics of these zoonotic viruses, originating from and hosted by wild animals, are most likely shaped by commensalism related to human activities.
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Evolución Biológica , Interacciones Huésped-Patógeno , Infecciones por Paramyxoviridae/veterinaria , Paramyxoviridae , Roedores/virología , Animales , Teorema de Bayes , Evolución Molecular , Filogenia , Roedores/clasificación , Roedores/genética , Proteínas Virales/genéticaRESUMEN
Tuberculosis is a worldwide disease considered as a major health problem with high morbidity and mortality rates. Poor detection of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis remains a major obstacle to the global control of this disease. Here we report the development of a new test based on the detection of the major virulent factor of Mtb, namely the early secreted antigenic target 6-kDa protein or ESAT-6. A label free electrochemical immunosensor using an anti-ESAT-6 monoclonal antibody as a bio-receptor is described herein. Anti-ESAT-6 antibodies were first covalently immobilized on the surface of a gold screen-printed electrode functionalized via a self-assembled thiol monolayer. Interaction between the bio-receptor and ESAT-6 antigen was evaluated by square wave voltammetry method using [Fe(CN)6]3-/4- as redox probe. The detection limit of ESAT-6 antigen was 7ng/ml. The immunosensor has also been able to detect native ESAT-6 antigen secreted in cell culture filtrates of three pathogenic strains of Mtb (CDC1551, H37RV and H8N8). Overall, this work describes an immune-electrochemical biosensor, based on ESAT-6 antigen detection, as a useful diagnostic tool for tuberculosis.
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Antígenos Bacterianos/análisis , Proteínas Bacterianas/análisis , Técnicas Biosensibles , Técnicas Electroquímicas , Mycobacterium tuberculosis/metabolismo , Tuberculosis/diagnóstico , Anticuerpos Inmovilizados/química , Anticuerpos Inmovilizados/inmunología , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Antígenos Bacterianos/genética , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Electrodos , Ferricianuros/química , Humanos , Límite de Detección , Miniaturización , Mycobacterium tuberculosis/aislamiento & purificación , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/aislamiento & purificación , Tuberculosis/microbiologíaRESUMEN
Zoonotic cutaneous leishmaniasis caused by Leishmania (L.) major parasites affects urban and suburban areas in the center and south of Tunisia where the disease is endemo-epidemic. Several cases were reported in human patients for which infection due to L. major induced lesions with a broad range of severity. However, very little is known about the mechanisms underlying this diversity. Our hypothesis is that parasite genomic variability could, in addition to the host immunological background, contribute to the intra-species clinical variability observed in patients and explain the lesion size differences observed in the experimental model. Based on several epidemiological, in vivo and in vitro experiments, we focused on two clinical isolates showing contrasted severity in patients and BALB/c experimental mice model. We used DNA-seq as a high-throughput technology to facilitate the identification of genetic variants with discriminating potential between both isolates. Our results demonstrate that various levels of heterogeneity could be found between both L. major isolates in terms of chromosome or gene copy number variation (CNV), and that the intra-species divergence could surprisingly be related to single nucleotide polymorphisms (SNPs) and Insertion/Deletion (InDels) events. Interestingly, we particularly focused here on genes affected by both types of variants and correlated them with the observed gene CNV. Whether these differences are sufficient to explain the severity in patients is obviously still open to debate, but we do believe that additional layers of -omic information is needed to complement the genomic screen in order to draw a more complete map of severity determinants.
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Cromosomas/química , Enfermedades Endémicas , Dosificación de Gen , Leishmania major/genética , Leishmaniasis Cutánea/epidemiología , Filogenia , Animales , ADN Protozoario/genética , Femenino , Estudios de Seguimiento , Genómica , Humanos , Mutación INDEL , Leishmania major/clasificación , Leishmania major/aislamiento & purificación , Leishmaniasis Cutánea/parasitología , Leishmaniasis Cutánea/transmisión , Ratones , Ratones Endogámicos BALB C , Filogeografía , Polimorfismo de Nucleótido Simple , Índice de Severidad de la Enfermedad , Túnez/epidemiologíaRESUMEN
Components of Pelagia noctiluca (P. noctiluca) venom were evaluated for their anticancer and nitric Oxide (NO) inhibition activities. Three fractions, out of four, obtained by gel filtration on Sephadex G75 of P. noctiluca venom revealed an important selective anti-proliferative activity on several cell lines such as human bladder carcinoma (RT112), human glioblastoma (U87), and human myelogenous leukemia (K562) but not on mitogen-stimulated peripheral blood mononuclear cells. Interestingly, P. noctiluca components showed an important dose-dependent anti-inflammatory activity, through inhibition of NO production via transcriptional regulation of Inducible NO Synthase (iNOS), in IFN-γ/LPS stimulated RAW 264.7 macrophages. These data strongly suggest that P. noctiluca venom could be used as a natural inhibitor of cancer cell lines and a potent anti-inflammatory agent for the treatment of anti-inflammatory diseases.