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21.
Molecular Biology Reports - Morocco is considered as an important producer of fish with more than one million tons of small pelagic fish caught per year, along more than 3400 km of...  相似文献   
22.
Diverse tetrapod track assemblages with Scoyenia invertebrate traces were discovered in the Triassic Timezgadiouine and Bigoudine formations of the Argana Basin (Western High Atlas, Morocco). The ichnofossils occur in alluvial plain sandstones and mudstones of the Irohalène Member (T5) and Tadart Ouadou Member (T6) considered Carnian-Norian in age by vertebrate remains and palynomorphs. Tetrapod footprints are assigned to Apatopus, Atreipus-Grallator, Eubrontes isp., Parachirotherium, cf. Parachirotherium postchirotherioides, Rhynchosauroides ispp., and Synaptichnium isp. They can be referred to lepidosauromorph/ archosauromorph, basal archosaur, and dinosauromorph trackmakers. Apatopus, represented by 11 tracks of a more than 4 m long trackway, is recorded for the first time outside of North America and Europe. The assemblage concurs with the proposed Late Triassic age of the track-bearing beds by the occurrence of Apatopus, Atreipus-Grallator, and Eubrontes. If this is accepted, the stratigraphic range of Synaptichnium and Parachirotherium, hitherto known only from Early or Middle Triassic deposits, has to be extended to the Carnian-Norian. The occurrence of Eubrontes in the Irohalene Member (T5) provides further evidence for large theropods in pre-Jurassic strata. All assemblages are referred to the Scoyenia ichnofacies indicating continental environments with alternating wet and dry conditions.  相似文献   
23.
An assemblage of abundant and well-preserved tetrapod footprints has been discovered in the Tanamert Member (T3) of the Triassic Timezgadiouine Formation (Argana basin, western High Atlas, Morocco). It is the first fossil record from T3. Surfaces from different localities show a uniform tetrapod ichnofauna that consists of chirotherian and small lacertoid forms. The chirotherians are assigned to the plexus Protochirotherium—Synaptichnium, their trackmakers interpreted as basal archosaurs. The lacertoid imprints show close affinities with Rhynchosauroides and may reflect archosauromorphs or lepidosauromorphs. Protochirotherium—Synaptichnium assemblages are characteristic of the Early Triassic and were known previously only from units of this age in central Europe. Biostratigraphically, the European record implies a wide-spread pre-Anisian Protochirotherium—Synaptichnium dominated assemblage preceding the first appearance of Chirotherium barthii near the Olenekian-Anisian boundary. The stratigraphic position of T3 between Late Permian (uppermost T2) and Middle Triassic (T4) and the European correlatives suggest an Early Triassic age of this unit. It is the first record of Early Triassic continental deposits in Morocco. The surfaces from T3 open up perspectives for further contributions to ecology, biogeography and locomotion of early archosaurs. Furthermore, excellent outcrops and quality of footprint preservation in the Argana basin offer a potential for clarification of ichnotaxonomic and biostratigraphic issues.  相似文献   
24.

Background

Traditional agroecosystems are known to host both large crop species diversity and high within crop genetic diversity. In a context of global change, this diversity may be needed to feed the world. Are these agroecosystems museums (i.e. large core collections) or cradles of diversity? We investigated this question for a clonally propagated plant, fig (Ficus carica), within its native range, in Morocco, but as far away as possible from supposed centers of domestication.

Results

Fig varieties were locally numerous. They were found to be mainly highly local and corresponded to clones propagated vegetatively. Nevertheless these clones were often sufficiently old to have accumulated somatic mutations for selected traits (fig skin color) and at neutral loci (microsatellite markers). Further the pattern of spatial genetic structure was similar to the pattern expected in natural population for a mutation/drift/migration model at equilibrium, with homogeneous levels of local genetic diversity throughout Moroccan traditional agroecosystems.

Conclusions

We conclude that traditional agroecosystems constitue active incubators of varietal diversity even for clonally propagated crop species, and even when varieties correspond to clones that are often old. As only female fig is cultivated, wild fig and cultivated fig probably constitute a single evolutionary unit within these traditional agroecosystems. Core collections, however useful, are museums and hence cannot serve the same functions as traditional agroecosystems.
  相似文献   
25.
The stability of the tri–μ–hydrido–bis[(η5–C5Me5)aluminum], Cp*2Al2H3, 1 is studied at B3LYP/6–311+G(d,p), CCSD(T)//B3LYP/6–311+G(d,p) and MP4//B3LYP/6–311+G(d,p) levels. The coordination between Al2H3 entity and both C5(CH3)5 groups is ensured by strong electrostatic and orbital interactions. The orbital analysis of the interacting fragments shows that Al2H3 acceptor, which keeps its tribridged structure, implies the vacant ( \texta1¢ ) \left( {{\text{a}}_1^\prime } \right) and five antibonding (a2¢¢ a_2^{\prime \prime } , e′ and e″) molecular orbitals to interact with two orbitals mixtures, b1 and e" of the donors (C5Me5). When we take into account the solvent effect, the computation shows that 1 seems to be stable in condensed phase with a tribridged bond between the Al atoms [Cp*Al(μ-H)3AlCp*], whereas in the gas phase, the monobridged Cp*AlH(μ-H)AlHCp* 4 is slightly favored (4 kcal mol−1). We propose that 1 could be prepared thanks to Cp*Al (2) and Cp*AlH2 (3) reaction in acidic medium. The experimental treatment of this type of metallocenes would contribute to the development of the organometallic chemistry of 13th group elements.   相似文献   
26.
The presence of Toxoplasma gondii DNA was detected in sera of acutely infected mice by polymerase chain reaction. Adult mice were inoculated intraperitoneally with 5 x 10(3) T. gondii RH strain tachyzoites. Five mice were killed every 3 hr from 3 to 21 hr post infection (PI) and every day from 1 to 7 days PI. Toxoplasma gondii DNA was first detected in 60% of the infected mice 18 hr PI and in 100% of the animals 21 hr PI and from 1 to 7 days PI. No mice survived longer than 7 days.  相似文献   
27.
Apolipoprotein E (apoE) is essential for the clearance of plasma chylomicron and VLDL remnants. The human APOE locus is polymorphic and 5-10% of APOE*2 homozygotes exhibit type-III hyperlipoproteinemia (THL), while the remaining homozygotes have less than normal plasma cholesterol. In contrast, mice expressing APOE*2 in place of the mouse Apoe (Apoe(2/2) mice) are markedly hyperlipoproteinemic, suggesting a species difference in lipid metabolism (e.g., editing of apolipoprotein B) enhances THL development. Since apoB-100 has an LDLR binding site absent in apoB-48, we hypothesized that the Apoe(2/2) THL phenotype would improve if all Apoe(2/2) VLDL contained apoB-100. To test this, we crossed Apoe(2/2) mice with mice lacking the editing enzyme for apoB (Apobec(-/-)). Consistent with an increase in remnant clearance, Apoe(2/2). Apobec(-/-) mice have a significant reduction in IDL/LDL cholesterol (IDL/LDL-C) compared with Apoe(2/2) mice. However, Apoe(2/2).Apobec(-/-) mice have twice as much VLDL triglyceride as Apoe(2/2) mice. In vitro tests show the apoB-100-containing VLDL are poorer substrates for lipoprotein lipase than apoB-48-containing VLDL. Thus, despite a lowering in IDL/LDL-C, substituting apoB-48 lipoproteins with apoB-100 lipoproteins did not improve the THL phenotype in the Apoe(2/2).Apobec(-/-) mice, because apoB-48 and apoB-100 differentially influence the catabolism of lipoproteins.  相似文献   
28.
, , , , , and 1992. Comparison of excretory/secretory and circulating antigens of Toxoplasma gondii by enzyme immunoassay and immunoblotting. International Journal for Parasitology 22: 1083–1088. Toxoplasma gondii trophozoites (RH strain) were cultured in embryonic fibroblasts in order to study the kinetics of production of excretory/secretory antigens, and the results were compared to the production of circulating antigens in an in vivo mouse model. By capture-ELISA, excretory/secretory antigens were first detected on the fourth day of culture whereas circulating antigens were first detected 1 day after infection. Similar concentrations of antigens were detected in both models as evidenced by comparable absorbance values. By immunoblotting, the excretory/secretory antigens were also detected later compared to circulating antigens (day 4 vs day 1). Seven major polypeptides were detected in both antigen preparations, six of them having the same molecular mass (110, 75,48, 30, 24 and 22 kDa).  相似文献   
29.
A successful Th cell response to bacterial infections is induced by mature MHC class II molecules presenting specific Ag peptides on the surface of macrophages. In recent studies, we demonstrated that infection with the conventional vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) specifically blocks the surface export of mature class II molecules in human macrophages by a mechanism dependent on inhibition of cathepsin S (Cat S) expression. The present study examined class II expression in macrophages infected with a rBCG strain engineered to express and secrete biologically active human Cat S (rBCG-hcs). Cat S activity was completely restored in cells ingesting rBCG-hcs, which secreted substantial levels of Cat S intracellularly. Thus, infection with rBCG-hcs, but not parental BCG, restored surface expression of mature MHC class II molecules in response to IFN-gamma, presumably as result of MHC class II invariant chain degradation dependent on active Cat S secreted by the bacterium. These events correlated with increased class II-directed presentation of mycobacterial Ag85B to a specific CD4(+) T cell hybridoma by rBCG-hcs-infected macrophages. Consistent with these findings, rBCG-hcs was found to accelerate the fusion of its phagosome with lysosomes, a process that optimizes Ag processing in infected macrophages. These data demonstrated that intracellular restoration of Cat S activity improves the capacity of BCG-infected macrophages to stimulate CD4(+) Th cells. Given that Th cells play a major role in protection against tuberculosis, rBCG-hcs would be a valuable tuberculosis vaccine candidate.  相似文献   
30.
Catalytic asymmetric benzylation of a dissymmetric tert‐butylglycinate ketimine, incorporating 1‐naphthyl and phenyl groups as the Schiff base substituents, under phase‐transfer conditions was investigated. It was interesting to note that the sense of asymmetric induction of the alkylation of Z‐imine stereoisomer is opposite to that of the corresponding E stereoisomer with a similar degree of enantioselectivity. More interestingly, the chiral Cu(II) complex of the Schiff base derived from (R)‐2‐phenylglycinol and 2‐hydroxy‐1‐naphthaldehyde was found to catalyze the same reaction under solid‐liquid conditions with comparable enantioselectivity (up to 60% ee) with respect to known cinchona alkaloid catalysts. The solvent/base‐system parameter was shown to control the optimal catalytic activity. Chirality 27:944–950, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
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