9 research outputs found
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 prĂ©sentons les rĂ©sultats prĂ©liminaires dâun 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 sâagit dâune zone caractĂ©risĂ©e par la prĂ©sence de lâun des mĂ©ga lacs qui existaient
dans le Sahara pendant les périodes humides à la fin du Quaternaire. La région est une zone
charniĂšre entre la MĂ©diterranĂ©e et le Sahara, donc favorable Ă lâĂ©tude 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 unâarticolata 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 6â12 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 (pâ<â0.05). 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