Climat, environnement et sociétés de la Préhistoire du sud tunisien: résultats préliminaires et perspectives de la recherche

We present the preliminary results of a Tunisian-Italian project of scientific collaboration in the field of environmental studies and prehistoric and anthropological research in southern Tunisia ruled by an interdisciplinary approach that includes geo-archeology, geochronology, geochemistry, palynology, paleoanthropology and population genetics. The research area is south of the Chott el Jerid and its surroundings, where the major physiographic feature is a large playa which contained one of the mega lakes that existed in the Sahara during wet periods in the late Quaternary. The region is a pivotal area between the Mediterranean and the Sahara, then favorable to study the cultural diffusion and humans displacements through different periods and environments.We present the preliminary results of a Tunisian-Italian project of scientific collaboration in the field of environmental studies and prehistoric and anthropological research in southern Tunisia ruled by an interdisciplinary approach that includes geo-archeology, geochronology, geochemistry, palynology, paleoanthropology and population genetics. The research area is south of the Chott el Jerid and its surroundings, where the major physiographic feature is a large playa which contained one of the mega lakes that existed in the Sahara during wet periods in the late Quaternary. The region is a pivotal area between the Mediterranean and the Sahara, then favorable to study the cultural diffusion and humans displacements through different periods and environments.Nous présentons les résultats préliminaires d’un projet Tuniso-Italien de collaboration scientifique dans le domaine des études environnementales et de la recherche préhistorique et anthropologique en Tunisie méridionale mené selon une approche interdisciplinaire qui comprend la géo-archéologie, la géochronologie, la géochimie, la palynologie, la paléoanthropologie et la génétique. La zone de recherche se trouve au sud du Chott el Jérid et ses environs. Il s’agit d’une zone caractérisée par la présence de l’un des méga lacs qui existaient dans le Sahara pendant les périodes humides à la fin du Quaternaire. La région est une zone charnière entre la Méditerranée et le Sahara, donc favorable à l’étude des diffusions culturelles et des déplacements humains à travers les différentes périodes et environnements

FIRST ARCHAEOLOGICAL INVESTIGATIONS IN THE CHOTT EL JERID AREA, SOUTHERN TUNISIA

Questo lavoro presenta i risultati preliminari delle ricerche archeologiche nel sud tunisino. Il programma triennale, sebbene fortemente ostacolato dalla grave situazione interna e drammaticamente scosso dagli attentati del 2015, ha comunque permesso una prima valutazione del potenziale archeologico della regione del Chott el Jerid, nel governatorato di Kebili. Le ricognizioni geoarcheologiche e i primi interventi di scavo, unitamente a un’articolata serie di campionamenti per la ricostruzione paleoambientale, per la cronologia e per lo studio genetico di popolazioni nomadi e sedentarie della regione, forniscono una prima base analitica per ricostruire gli sviluppi culturali del Tardo Quaternario, dalla Middle Stone Age, attraverso la transizione Pleistocenee Olocene (facies Iberomaurusiano e Capsiano), fino al tardo Neolitico

Identification of broadly conserved cross-species protective Leishmania antigen and its responding CD4+ T cells

International audienceThere is currently no clinically effective vaccine against leishmaniasis because of poor understanding of the antigens that elicit dominant T cell immunity. Using proteomics and cellular immunology, we identified a dominant naturally processed peptide (PEPCK335-351) derived from Leishmania glycosomal phosphoenolpyruvate carboxykinase (PEPCK). PEPCK was conserved in all pathogenic Leishmania, expressed in glycosomes of promastigotes and amastigotes, and elicited strong CD4(+) T cell responses in infected mice and humans. I-A(b)-PEPCK335-351 tetramer identified protective Leishmania-specific CD4(+) T cells at a clonal level, which comprised similar to 20% of all Leishmania-reactive CD4(+) T cells at the peak of infection. PEPCK335-351-specific CD4(+) T cells were oligoclonal in their T cell receptor usage, produced polyfunctional cytokines (interleukin-2, interferon-gamma and tumor necrosis factor), and underwent expansion, effector activities, contraction, and stable maintenance after lesion resolution. Vaccination with PEPCK peptide, DNA expressing full-length PEPCK, or rPEPCK induced strong durable cross-species protection in both resistant and susceptible mice. The effectiveness and durability of protection in vaccinated mice support the development of a broadly cross-species protective vaccine against different forms of leishmaniasis by targeting PEPCK

Antioxidant enzymes activities in obese Tunisian children

<p>Abstract</p> <p>Background</p> <p>The oxidant stress, expected to increase in obese adults, has an important role in the pathogenesis of many diseases. It results when free radical formation is greatly increased or protective antioxidant mechanisms are compromised. The main objective of this study is to evaluate the antioxidant response to obesity-related stress in healthy children.</p> <p>Methods</p> <p>A hundred and six healthy children (54 obese and 52 controls), aged 6–12 years old, participated in this study. The collected data included anthropometric measures, blood pressure, fasting glucose, total cholesterol, triglycerides and enzymatic antioxidants (Superoxide dismutase: SOD, Catalase: CAT and Glutathione peroxidase: GPx).</p> <p>Results</p> <p>The first step antioxidant response, estimated by the SOD activity, was significantly higher in obese children compared with normal-weight controls (p < 0.05). Mean activities of anti-radical GPx and CAT enzymes were not affected by the BMI increase. Although, total cholesterol levels were statistically higher in the obese group, there was no significant association with the SOD activity.</p> <p>Conclusions</p> <p>The obesity-related increase of the oxidant stress can be observed even in the childhood period. In addition to the complications of an increased BMI, obesity itself can be considered as an independent risk factor of free radical production resulting in an increased antioxidant response.</p

Berbers and Arabs: Tracing the genetic diversity and history of Southern Tunisia through genome wide analysis

Objectives: Tunisia has been a crossroads for people from Africa, Europe, and the Middle East since prehistoric times. At present, it is inhabited by two main ethnic groups, Arabs and Berbers, and several minorities. This study aims to advance knowledge regarding their genetic structure using new population samplings and a genome-wide approach. Materials and Methods: We investigated genomic variation, estimated ancestry components and dated admixture events in three Berber and two Arab populations from Southern Tunisia, mining a dataset including Middle Eastern, sub-Saharan, and European populations. Results: Differences in the proportion of North African, Arabian, and European ancestries and the varying impact of admixture and isolation determined significant heterogeneity in the genetic structure of Southern Tunisian populations. Admixture time estimates show a multilayer pattern of admixture events, involving both ethnolinguistic groups, which started around the mid XI century and lasted for nearly five centuries. Discussion: Our study provides evidence that the relationships between genetic and cultural diversity of old and new inhabitants of North Africa in southern Tunisia follow different patterns. The Berbers seem to have preserved a significant part of their common genomic heritage despite Islamization, Arab cultural influence, and linguistic diversity. Compared to Morocco and Algeria, southern Tunisian Arabs have retained a higher level of Arabian ancestry. This is more evident in the semi-nomad R'Baya, who have kept their original Bedouin lifestyle, than in the population from Douz, who have undergone multiple events of stratification and admixture