Formal Verification Integration Approach for DSML

International audienceThe application of formal methods (especially, model check- ing and static analysis techniques) for the verification of safety critical embedded systems has produced very good results and raised the inter- est of system designers up to the application of these technologies in real size projects. However, these methods usually rely on specific verifica- tion oriented formal languages that most designers do not master. It is thus mandatory to embed the associated tools in automated verification toolchains that allow designers to rely on their usual domain-specific modeling languages (DSMLs) while enjoying the benefits of these power- ful methods. More precisely, we propose a language to formally express system requirements and interpret verification results so that system designers (DSML end-users) avoid the burden of learning some formal verification technologies. Formal verification is achieved through trans- lational semantics. This work is based on a metamodeling pattern for executable DSML that favors the definition of generative tools and thus eases the integration of tools for new DSML

Plasmodium falciparum metacaspase PfMCA-1 triggers a z-VAD-fmk inhibitable protease to promote cell death.

Activation of proteolytic cell death pathways may circumvent drug resistance in deadly protozoan parasites such as Plasmodium falciparum and Leishmania. To this end, it is important to define the cell death pathway(s) in parasites and thus characterize proteases such as metacaspases (MCA), which have been reported to induce cell death in plants and Leishmania parasites. We, therefore, investigated whether the cell death function of MCA is conserved in different protozoan parasite species such as Plasmodium falciparum and Leishmania major, focusing on the substrate specificity and functional role in cell survival as compared to Saccharomyces cerevisae. Our results show that, similarly to Leishmania, Plasmodium MCA exhibits a calcium-dependent, arginine-specific protease activity and its expression in yeast induced growth inhibition as well as an 82% increase in cell death under oxidative stress, a situation encountered by parasites during the host or when exposed to drugs such as artemisins. Furthermore, we show that MCA cell death pathways in both Plasmodium and Leishmania, involve a z-VAD-fmk inhibitable protease. Our data provide evidence that MCA from both Leishmania and Plasmodium falciparum is able to induce cell death in stress conditions, where it specifically activates a downstream enzyme as part of a cell death pathway. This enzymatic activity is also induced by the antimalarial drug chloroquine in erythrocytic stages of Plasmodium falciparum. Interestingly, we found that blocking parasite cell death influences their drug sensitivity, a result which could be used to create therapeutic strategies that by-pass drug resistance mechanisms by acting directly on the innate pathways of protozoan cell death

Implication of different domains of the Leishmania major metacaspase in cell death and autophagy

International audienceMetacaspases (MCAs) are cysteine peptidases expressed in plants, fungi and protozoa, with a caspase-like histidine-cysteine catalytic dyad, but differing from caspases, for example, in their substrate specificity. The role of MCAs is subject to debate: roles in cell cycle control, in cell death or even in cell survival have been suggested. In this study, using a Leishmania major MCA-deficient strain, we showed that L. major MCA (LmjMCA) not only had a role similar to caspases in cell death but also in autophagy and this through different domains. Upon cell death induction by miltefosine or H2O2, LmjMCA is processed, releasing the catalytic domain, which activated substrates via its catalytic dyad His/Cys and a proline-rich C-terminal domain. The C-terminal domain interacted with proteins, notably proteins involved in stress regulation, such as the MAP kinase LmaMPK7 or programmed cell death like the calpain-like cysteine peptidase. We also showed a new role of LmjMCA in autophagy, acting on or upstream of ATG8, involving Lmjmca gene overexpression and interaction of the C-terminal domain of LmjMCA with itself and other proteins. These results allowed us to propose two models, showing the role of LmjMCA in the cell death and also in the autophagy pathway, implicating different protein domains

Semantic Heterogeneity in the Formal Development of Complex Systems: An Introduction

International audienceSystem engineering is a complex discipline[1], which is becoming more and more complicated by the heterogeneity of the subsystem components[2] and of the models involved in their design. This complexity can be managed only through the use of formal methods[3]. However, in general the engineering of software in such systems leads to a need for a mix of modelling languages and semantics; and this often leads to unexpected and undesirable interactions between components at all levels of abstraction[4]. There are currently no generally applicable tools for dealing with this heterogeneity of interactions in the engineering of complex systems

Tuberculosis lymphadenitis in a south-eastern region in Tunisia: Epidemiology, clinical features, diagnosis and treatment

Aim: To evaluate patients’ profiles, demographics, clinical and therapeutic approaches and strategies in patients with tuberculous lymphadenitis (TBG). Patients and methods: A retrospective study of all TBG-confirmed cases admitted in a tuberculosis specific health care facility between 1 January 2009 and 16 June 2013. Results: A total of 181 clinical files were examined. Mean age was 32 years old; the female/male ratio was 1.78 to 1. Raw milk consumption was noted in 1/3 of patients. Most cases involved the head and neck region (83.4%), nodes involvement, including axillary (12 cases), and mediastinal (9 cases). Clinical symptoms were present in only 55.2%. TST was conducted with 82.6% positive responses. Diagnostics confirmation was done with anatomical pathology in most of the patients; only 56 of them had any microbiology analysis done. Demonstration of acid-fast bacilli in microscopy from either fine-needle aspirates or biopsies was done in 17.5%, and cultures yielded positive results in 27%. Treatment duration was varied. Paradoxical reactions were noted in 12% and persistent lymphadenopathy after treatment completion was noted in 10% of cases. Conclusions: TBG remains a disease of interest. Today, its diagnosis and management is still a problem despite its increasing worldwide incidence, and especially in this study area. Disease control should be strengthened in this country

Antagonic activities of Trypanosoma cruzi metacaspases affect the balance between cell proliferation, death and differentiation

Metacaspases are distant relatives of animal caspases present in plants, fungi and protozoa. At variance with caspases, metacaspases exhibit stringent specificity for basic amino-acid residues and are absolutely dependent on millimolar concentrations of calcium. In the protozoan parasite Trypanosoma cruzi, metacaspases have been suggested to be involved in an apoptosis-like phenomenon upon exposure of the parasite to fresh human serum (FHS). Nuclear relocalization of metacaspases was observed after FHS treatment and overexpression of metacaspase-5 led to enhanced sensitivity to this stimulus. Here we report some biochemical properties of T. cruzi metacaspases. Performing fluorescent-activated cell sorting (FACS) analysis of epimastigotes inducibly overexpressing metacaspase-3, we demonstrate a role for this metacaspase in cell cycle progression, protection of epimastigotes from naturally occurring cell death and differentiation to infective metacyclic trypomastigotes. We also show that regulation of metacaspase-3 activity is important for cell cycle completion inside the mammalian host. On the other hand, inducible overexpression of metacaspase-5 lacking its C-terminal domain caused an apoptotic-like response. These results suggest that the two T. cruzi metacaspases could play an important role in the life cycle and bring to light the close relationship between cell division, death and differentiation in this ancient unicellular eukaryote. © 2012 Macmillan Publishers Limited All rights reserved.Fil: Laverriere, Marc. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Cazzulo, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Alvarez, Vanina Eder. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin