cDNA cloning and functional expression of the α-d-galactose-binding lectin frutalin in escherichia coli

cDNA clones encoding frutalin, the α-d-galactose-binding lectin expressed in breadfruit seeds (Artocarpus incisa), were isolated and sequenced. The deduced amino acid sequences indicated that frutalin may be encoded by a family of genes. The NCBI database searches revealed that the frutalin sequence is highly homologous with jacalin and mornigaG sequences. Frutalin cDNA was re-amplified and cloned into the commercial expression vector pET-25b(+) for frutalin production in Escherichia coli. An experimental factorial design was employed to maximise the soluble expression of the recombinant lectin. The results indicated that temperature, time of induction, concentration of IPTG and the interaction between the concentration of IPTG and the time of induction had the most significant effects on the soluble expression level of recombinant frutalin. The optimal culture conditions were as follows: induction with 1 mM IPTG at 22°C for 20 h, yielding 16 mg/l of soluble recombinant frutalin. SDS-PAGE and Western blot analysis revealed that recombinant frutalin was successfully expressed by bacteria with the expected molecular weight (17 kDa). These analyses also showed that recombinant frutalin was mainly produced as insoluble protein. Recombinant frutalin produced by bacteria revealed agglutination properties and carbohydrate-binding specificity similar to the native breadfruit lectin.Fundação para a Ciência e a Tecnologia (FCT

Mesozoic emplacement and subsequent deformation of the Cuaro sills and dykes (Uruguay) from anisotropy of magnetic susceptibility.

International audienc

Ar-40/Ar-39 geochronology and Sr-Pb isotopic evidence of post-collisional extensional volcanism of the eastern Pontide paleo-arc, NE Turkey

Tertiary aged post-collisional volcanics show stratigraphic, petrographic and age differences in the northern and southern zones of the eastern Pontides. The Eocene sequences in E-W direction are exposed as basin fillings in the southern zone and overlay the Upper Cretaceous and Paleocene aged units. The volcanic rocks in the Gümü..hane and Alucra areas are mainly basalt, basaltic andesite, andesite, trachyandesite and rare rhyolite-obsidien. Petrochemically, the Gümü..hane area volcanics vary from basalt to dacite with low alkali tendency, whereas the Alucra area volcanics from basalt to basaltic-trachyandesite with high alkali tendency. The differences on the element variations of the tholeiitic-alkaline transition and calc-alkaline rocks can be explained by fractionation of clinopyroxene + hornblende + plagioclase ± magnetite ± apatite. The trace element variations show some similarities with enrichment of LILE and negative Nb, Ta and Ti anomalies. Particularly, the enrichments in LILE and a lesser extent in LREE, but the depletions in HFSE indicate that the rocks evolved from a parental magma derived from an enriched source formed by mixing of slab and asthenospheric melts. The chondrite-normalized-REE patterns of these volcanics resemble to each other and spoon-shaped with low to medium enrichment (LaN/LuN=2-35), indicating similar source area for the Gümü..hane and Alucra area volcanics. The 40Ar-39Ar dating of the studied volcanics are between 37.7±0.2 and 44.5±0.2 Ma. The (87Sr/86Sr)i values of the rocks are between 0.70457 and 0.70556, and their 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb isotopic ratios range 18.59 to 18.73, 15.62 to 15.64 and 38.65 to 38.86, respectively. Pb- and Sr- isotopic ratios may imply that the rocks derived from a source region at the boundary of the mantle-crust, but the samples with low (87Sr/86Sr)i values (<0.705) reflect the mantle source in their origin. The increasing values of SiO2 (wt.%), Sr (ppm) ve (1/Sr)x103 ppm-1 versus (87Sr/86Sr)i values suggest fractionational crystallisation (FC) rather than assimilation (AFC) in their evolution. Based on volcanic variety and distributions together with field and petrological data, volcanic activity in the Eocene time of the eastern Pontide is closely related to extensional tectonic regime with transtansional faults

The Limpopo magma‐rich transform margin, South Mozambique – part 2: Implications for the Gondwana breakup

International audienceThe rifted continental margins of Mozambique provide excellent examples of continental passive margins with a significant structural variability associated with magmatism and inheritance. Despite accumulated knowledge, the tectonic structure and nature of the crust beneath the South Mozambique Coastal Plain (SMCP) are still poorly known. This study interprets high-resolution seismic reflection data paired with data from industry-drilled wells and proposes a structural model of the Limpopo transform margin in a magma-rich context. Results indicate that the Limpopo transform margin is characterized by an ocean-continent transition that links the Beira-High and Natal valley margin segments and represents the western limit of the continental crust, separating continental volcano-sedimentary infilled grabens from the oceanic crust domain. These basins result from the emplacement of the Karoo Supergroup during a Permo-Triassic tectonic event, followed by an Early Jurassic tectonic and magmatic event. This latter led to the establishment of steady-state seafloor spreading at ca.156 Ma along the SMCP. A Late Jurassic to Early Cretaceous event corresponds to formation of the Limpopo transform fault zone. Which accommodated the SSE-ward displacement of Antarctica with respect to Africa. We define a new type of margin: the magma-rich transform margin, characterized by the presence of voluminous magmatic extrusion and intrusion coincident with the formation and evolution of the transform margin. The Limpopo transform fault zone consists of several syn-transfer and -transform faults rather than a single transform fault. The intense magmatic activity was associated primarily with mantle dynamics, which controlled the large-scale differential subsidence along the transform margin

Evolution of the Glorieuses seamount in the SW Indian Ocean and surrounding deep Somali Basin since the Cretaceous

Little is known about the geological history of the Glorieuses seamount including basic information about its age and origin related to the regional evolution of the southern tip of the Somali Basin. This study focused on describing and reconstructing the long-term stratigraphic evolution of the Glorieuses seamount (SW Indian Ocean) to identify the mechanisms that have occurred through time to finally shape the emerged modern islands. Distinct terrace levels, currently submerged along the flanks of the seamount and surrounding seamounts, have already been interpreted as resulting from successive carbonate development and back-stepping episodes over the last 62 Myr. New isotopic and biostratigraphic dating on the flanks of the seamount, coupled with sequence stratigraphic interpretation of seismic profiles acquired in the adjacent basin, provide new constraints for the Late Cretaceous and Cenozoic vertical evolution of the seamount topped by carbonate platforms and sedimentation in the surrounding deep basin. Even if starved steep slopes prevent a straightforward source-to-sink continuity between the platform and the basin domains, our findings propose a consistent chronostratigraphic framework for the identified seismic markers and sequences in the deep basin, and discuss a long-term geological model that includes the main driving factors behind deposition (volcanic events, subsidence vs uplift phases, climate and hydro-dynamism changes) and their quantitative impact on the evolution of the isolated carbonate sedimentary system. Our results show that: (i) the Glorieuses volcanic seamount emerged from two successive Late Cretaceous magmatic pulses, firstly during the Turonian, then during the Maastrichtian (ii) at least two potential uplift phases are recognized during the Tertiary (Paleogene and/or the Eocene and Tortonian); (iii) basinal sedimentation recorded an abrupt change probably related to major regional hydro-dynamical changes in Late Eocene times in the Western Indian Ocean; (iv) the export of sediments from the platform towards the basin (numerous gravity flow processes) is strongly enhanced after the Mid Miocene, and is probably linked to the onset of the Asian monsoon winds and bipolar circulation. Finally, the Glorieuses seamount, although located in the vicinity of the Comoros islands, appears to have a much longer history and is geologically more comparable to the nearby Seychelles. This long-term study has enabled us to associate the Glorieuses seamount with the SSE-NNW Madagascar-Seychelles alignment rather than with the Comoro hot spot evolution