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51.
Angelo Peccerillo Giuliano F. Panza Abdelkrim Aoudia Maria Luce Frezzotti 《Rendiconti Lincei》2008,19(4):291-309
Shear-wave (V
S
) tomography along transects across the Western-Central Mediterranean area reveals heterogeneous lateral and vertical physical
characteristics in the lithosphere-asthenosphere system (LAS). A 50 km thick low velocity layer (LVL), with V
S
∼ 4.0–4.2 km/sec, typical of low rigidity fluid-bearing mantle material, is observed at a depth of about 70–120 km from offshore
Provence, to Sardinia and the Central Tyrrhenian Sea. This LVL, enclosed between higher velocity mantle rocks, rises to a
depth of less than 30 km below the recent and active volcanoes of Central Italy and the Southern Tyrrhenian Sea, where a maximum
in the heath flow is observed. The LVL is absent beneath Southeastern France and the northern border of the African foreland.
In the Balearic Sea-Sardinia-Central Tyrrhenian section, the depth of LVL corresponds to pressure conditions of minimum temperature
of peridotite+CO2+H2O solidus, consistent with conditions where fluid loss from the slab and mantle flow over the subducting plate favor significant
melt generation above steep, west-dipping subduction zones. It is suggested that LVL in the Balearic-Tyrrhenian domains is
the result of mantle contamination and melting left behind by the eastward retreating Adriatic-Ionian subducting plates from
Oligo-Miocene to present. This layer also marks a discontinuity between the lithospere and underlying mantle behind the subduction
zone, favoring detachment and westward drift of the lithosphere, and consequent opening of backarc basins.
These data support the hypothesis that the orogenic Oligocene to Quaternary volcanism in the Western Mediterranean area is
the effect of shallow mantle processes, and argue against the presence of deep mantle plumes. A shallow-mantle origin is also
suggested for the EM1-type Plio-Quaternary anorogenic magmatism in Sardinia and for the FOZO-DMM-type magmatism on the northern
margin of the African foreland.
相似文献
52.
Jacques Noël Katharina Zimmermann Jérome Busserolles Emanuel Deval Abdelkrim Alloui Sylvie Diochot Nicolas Guy Marc Borsotto Peter Reeh Alain Eschalier Michel Lazdunski 《The EMBO journal》2009,28(9):1308-1318
The sensation of cold or heat depends on the activation of specific nerve endings in the skin. This involves heat‐ and cold‐sensitive excitatory transient receptor potential (TRP) channels. However, we show here that the mechano‐gated and highly temperature‐sensitive potassium channels of the TREK/TRAAK family, which normally work as silencers of the excitatory channels, are also implicated. They are important for the definition of temperature thresholds and temperature ranges in which excitation of nociceptor takes place and for the intensity of excitation when it occurs. They are expressed with thermo‐TRP channels in sensory neurons. TRAAK and TREK‐1 channels control pain produced by mechanical stimulation and both heat and cold pain perception in mice. Expression of TRAAK alone or in association with TREK‐1 controls heat responses of both capsaicin‐sensitive and capsaicin‐insensitive sensory neurons. Together TREK‐1 and TRAAK channels are important regulators of nociceptor activation by cold, particularly in the nociceptor population that is not activated by menthol. 相似文献
53.
Abdellah El Aissouq Hamid Toufik Mourad Stitou Abdelkrim Ouammou Fatima Lamchouri 《International journal of peptide research and therapeutics》2020,26(3):1335-1351
The c-Jun N-terminal Kinase 3 (JNK3) is a family of protein kinases that plays an important role in the neurodegenerative diseases such as Alzheimer’ 相似文献
54.
Baraket Ghada Ben Abdelkrim Ahmed Chatti Khaled Saddoud Olfa Mars Messaoud Trifi Mokhtar Salhi-Hannachi Amel 《Biochemical Systematics and Ecology》2010
Here, we report the nucleotide variation in two non-coding regions of the chloroplast DNA (cpDNA) to construct a possible evolutionary scenario in Ficus carica L. Our results suggest the occurrence of haplotypic and nucleotide diversity with a large variation level of chloroplast non-coding regions. Furthermore, our results demonstrated an explicit rejection of the null hypothesis that within F. carica the intron trnL and the spacer trnL-trnF evolved under a strictly neutral model of molecular evolution. Although, recent population expansion could serve as one alternative explanation for the detected excess of singleton, our results imply a positive selection and the genetic hitchhiking effect is unlikely. Parameters performed supported scenario of sweep selection and recent expansion of F. carica across Tunisia. Our results indicate that both positive selection and demographic histories have jointly contributed to the observed patterns of nucleotide diversity and haplotypes structure. Based on the results, we characterize the fig resources and provide several suggestions for effective conservation and improvement programs. 相似文献
55.
Olivier Véron Jean Philippe Blondeau Naas Abdelkrim Esidor Ntsoenzok 《Plasmonics (Norwell, Mass.)》2010,5(2):213-219
The photoluminescence of silver nanoparticles glasses obtained by ionic exchange and annealing is investigated for various
ionic exchange times. These glasses are prepared by immersion of silicate glass samples in a molten salt bath of molar concentration
10% AgNO3 in NaNO3 at T = 320 °C. Scanning electron microscopy measurement in electron diffraction scattering (EDS) configuration confirms the silver
presence in the various glasses, and the UV/visible absorption gives the evolution of the spectra after ionic exchange and
plasmon resonance apparition after annealing. After annealing at 450 °C, both diagnostics inform us about the particles’ formation
and the silver rediffusion. Silver nanoparticle growth after annealing prior leads to photoluminescence exaltation and quenching
for the longest exchange samples. Subsequently, we propose potential mechanisms of the nanoparticle formation with an initial
depolymerization of the silicate network during the ionic exchange and repolymerization during annealing. 相似文献
56.
Nitric oxide mediates the survival action of IGF-1 and insulin in pancreatic beta cells 总被引:1,自引:0,他引:1
Cahuana GM Tejedo JR Hmadcha A Ramírez R Cuesta AL Soria B Martin F Bedoya FJ 《Cellular signalling》2008,20(2):301-310
Generation of low levels of nitric oxide (NO) contributes to beta cell survival in vitro. The purpose of this study was to explore the link between NO and the survival pathway triggered by insulin-like growth factor-1 (IGF-1) and insulin in insulin producing RINm5F cells and in pancreatic islets. Results show that exposure of cells to IGF-1/insulin protects against serum deprivation-induced apoptosis. This action is prevented with inhibitors of NO generation, PI3K and Akt. Moreover, transfection with the negative dominant form of the tyrosine kinase c-Src abrogates the effect of IGF-1 and insulin on DNA fragmentation. An increase in the expression level of NOS3 protein and in the enzyme activity is observed following exposure of serum-deprived RINm5F cells to IGF-1 and insulin. Phosphorylation of IRS-1, IRS-2 and to less extent IRS-3 takes place when serum-deprived RINm5F cells and rat pancreatic islets are exposed to either IGF-1, insulin, or diethylenetriamine nitric oxide adduct (DETA/NO). In human islets, IRS-1 and IRS-2 proteins are present and tyrosine phosphorylated upon exposure to IGF-1, insulin and DETA/NO. Both rat and human pancreatic islets undergo DNA fragmentation when cultured in serum-free medium and IGF-1, insulin and DETA/NO protect efficiently from this damage. We then conclude that generation of NO participates in the activation of survival pathways by IGF-1 and insulin in beta cells. 相似文献
57.
Louppe Vivien Lalis Aude Abdelkrim Jawad Baron Juliette Bed’Hom Bertrand Becker Anne A. M. J. Catzeflis François Lorvelec Olivier Zieger Ulrike Veron Géraldine 《Biological invasions》2021,23(8):2573-2590
Biological Invasions - The small Indian mongoose has been introduced into several important hotspots of biodiversity and is considered the wild carnivore with the greatest negative impact on... 相似文献
58.
Ethylene and gibberellins have a synergistic stimulatory effect on hypocotyl elongation of light-grown Arabidopsis thaliana (L.) Heynh. seedlings. A screen for mutants with decreased response to these hormones led to the isolation of a novel allele
(amp1-7) of the ALTERED MERISTEM PROGRAM (AMP) 1 locus. The amp1-7 allele contains a missense mutation causing a phenotype, which is weaker than that of the amp1-1 mutant that carries a nonsense mutation. The mutant phenotype prompted the hypothesis that AMP1 is involved in ethylene and
GA signalling pathways or in a parallel pathway-controlling cell and hypocotyl elongation and cellular organization. Amp1 mutants contain higher zeatin concentrations causing enlargement of the apical meristem, which was confirmed by cytokinin
application to wild type seedlings. Light grown amp1 seedlings have shorter hypocotyls than wild type; however, application of cytokinins promotes hypocotyl elongation of both
Col-0 and amp1. We suggest that in amp1 mutants either zeatin overproduction or its action is strictly localized.
Nelson J. M. Saibo and Wim H. Vriezen contributed equally to this work. 相似文献
59.
Abdelkrim MA Mallem MY Chatagnon G Gogny M Desfontis JC Noireaud J 《Canadian journal of physiology and pharmacology》2012,90(4):407-414
Circulating autoantibodies directed against the 2nd extracellular loop (EL-2) of β(1)-adrenoceptors (β(1)-AABs) have been detected in the serum of patients with various cardiovascular pathologies. β(1)-AABs induce agonistic, positive inotropic effects via β(1)-adrenoceptors (β(1)ARs). In the mammalian heart, β(1)-AR can exist in 2 distinct activated configurations (the so-called high- and low-affinity states). The aim of the present study was to investigate whether the action of β(1)-AAB is dependent on the affinity state of β(1)AR in isolated ventricular cardiomyocytes of adult Wistar rats. Immunoglobulin G (IgG) containing β(1)-AAB obtained from animals immunized with a peptide corresponding to the EL-2 of human β(1)-AR, caused a dose-dependent increase in cell shortening. Isoproterenol-induced inotropy was significantly reduced in cardiomyocytes that had been preincubated with IgG containing β(1)-AAB and in cardiomyocytes isolated from immunized rats. The negative effects of preincubation with IgG containing β(1)-AAB on the response to isoproterenol was inhibited in the presence of bisoprolol. CGP 12177A and pindolol-induced inotropy was not affected by IgG preincubation or immunization. No detectable inotropic effect of cell shortening was obtained with IgG containing β(1)-AAB in the presence of propranolol and 3-isobutyl-1-methylxanthine. The present study demonstrates that β(1)-AABs have no agonist/antagonist-like effects upon low-affinity state β(1)-ARs. This result indicates that β(1)-AABs recognize and stabilize the high-affinity state, but are unable to stabilize and (or) induce the low-affinity state receptor. 相似文献
60.
Solution structure of human BCL-w: modulation of ligand binding by the C-terminal helix 总被引:7,自引:0,他引:7
Denisov AY Madiraju MS Chen G Khadir A Beauparlant P Attardo G Shore GC Gehring K 《The Journal of biological chemistry》2003,278(23):21124-21128
The structure of human BCL-w, an anti-apoptotic member of the BCL-2 family, was determined by triple-resonance NMR spectroscopy and molecular modeling. Introduction of a single amino acid substitution (P117V) significantly improved the quality of the NMR spectra obtained. The cytosolic domain of BCL-w consists of 8 alpha-helices, which adopt a fold similar to that of BCL-xL, BCL-2, and BAX proteins. Pairwise root meant square deviation values were less than 3 A for backbone atoms of structurally equivalent regions. Interestingly, the C-terminal helix alpha8 of BCL-w folds into the BH3-binding hydrophobic cleft of the protein, in a fashion similar to the C-terminal transmembrane helix of BAX. A peptide corresponding to the BH3 region of the pro-apoptotic protein, BID, could displace helix alpha8 from the BCL-w cleft, resulting in helix unfolding. Deletion of helix alpha8 increased binding affinities of BCL-w for BAK and BID BH3-peptides, indicating that this helix competes for peptide binding to the hydrophobic cleft. These results suggest that although the cytosolic domain of BCL-w exhibits an overall structure similar to that of BCL-xL and BCL-2, the unique organization of its C-terminal helix may modulate BCL-w interactions with pro-apoptotic binding partners. 相似文献