Based on new structural, sedimentary, stratigraphic and seismic reflection data from Cretaceous sequences of the Zemlet el Beidha anticline of the northern Chotts range (South Tunisia), this study yields fresh insights into the geodynamic evolution of the South Tethyan margin. The rifting of the margin started in the Triassic-Jurassic and continued during the Aptian-Albian. In this last period N to NE trending extension was associated with WNW and NW trending normal faults, bounding the developing horsts and grabens structures. This tectonic framework is highlighted by strong thickness and facies changes in the Aptian-Albian series associated with slumps and syntectonic conglomerates. During the Coniacian to Santonian times, the study area was characterized by continued subsidence. Consequently, the Coniacian-Santonian series are represented by sedimentary infilling consisting of post-rift marl-rich sequences followed by limestone and marl sequences. 2 Folds geometry and associated faults system and tectonics analysis, confirm the role of the Aptian-Albian rifting inheritance faulting in the structuring and the development of the folds and thrusts belts of the southern Tunisian Atlas during the Cenozoic inversion, in particular in the development of the ENE striking structures such as the Zemlet el Beidha anticline.
Neuroinflammation characterized by activation of glial cells is observed in various neurodegenerative diseases including Alzheimer's disease (AD). Although the reduction of ether-type glycerophospholipids, plasmalogens (Pls), in the brain is reported in AD patients, the mechanism of the reduction and its impact on neuroinflammation remained elusive. In the present study, we found for the first time that various inflammatory stimuli reduced Pls levels in murine glial cells via NF-κB activation, which then downregulated a Pls-synthesizing enzyme, glycerone phosphate O-acyltransferase (Gnpat) through increased c-Myc recruitment onto the promoter. We also found that systemic injection of lipopolysaccharide, aging, and chronic restraint stress reduced brain Pls contents that were associated with glial NF-κB activation, an increase in c-Myc expression, and downregulation of in the mouse cortex and hippocampus. More interestingly, the reduction of Pls contents in the murine cortex itself could increase the activated phenotype of microglial cells and the expression of proinflammatory cytokines, suggesting further acceleration of neuroinflammation by reduction of brain Pls. A similar mechanism of reduction was also found in human cell lines, triple-transgenic AD mouse brain, and postmortem human AD brain tissues. These findings suggest a novel mechanism of neuroinflammation that may explain prolonged progression of AD and help us to explore preventive and therapeutic strategies to treat neurodegenerative diseases. Ether-type glycerophospholipids, plasmalogens (Pls), are reduced in the brain of Alzheimer disease (AD) patients. We found that inflammatory stimuli reduced Pls contents by downregulation of the Pls-synthesizing enzyme glycerone phosphate O-acyltransferase (Gnpat) through NF-κB-mediated recruitment of c-Myc onto the promoter in both murine and human cell lines. Murine brains after systemic lipopolysaccharide, chronic stress, and aging, as well as triple-transgenic AD mice and postmortem human AD brain tissues all showed increased c-Myc and reduced expression. Interestingly, knockdown of itself activated NF-κB in glial cell lines and microglia in mouse cortex. Our findings provide a new insight into the mechanism of neuroinflammation and may help to develop a novel therapeutic approach for neurodegenerative diseases such as AD.
The Medjez-el-Bab (MEB) box anticline, northern Tunisia, gives new evidence allowing us to precise the tectonic agenda of the North African paleo-margin inversion. On the one hand, the examination of this structure permits us to show that the inversion began approximately by the transition between the Lower and Upper Senonian. On the other hand, it highlights the occurrence of a Middle-to-Late Eocene compressive tectonic phase (the so-called Atlas or Atlasic phase), which is well recorded by reworking material within the Middle Eocene deposits as well as by the angular unconformity of the Late Eocene beds, supporting the hypothesis of compressive Eocene phase (Atlasic phase) generalized all over the Maghreb.
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