Remarks on the identification of the Albian/Cenomanian boundary and taxonomic clarification of the planktonic foraminifera index species globotruncanoides, brotzeni and tehamaensis

The planktonic foraminifera assemblage across the Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage defined at Mont Risou (Haute-Alpes in France) is here restudied to clarify the identification and stratigraphic distribution of Thalmanninella globotruncanoides ( = Rotalipora globotruncanoides Sigal, 1948) and Pseudothalmanninella tehamaensis ( = Rotalipora tehamaensis Marianos & Zingula, 1966) whose appearance levels are primary and secondary criteria for placing the Albian/Cenomanian boundary. Since the ratification of the GSSP in 2002, the identification of the foraminifera index species across the Albian/Cenomanian boundary has been reported to be sometimes difficult either because of their rarity or uncertainty in the taxonomic identifications. We discuss the taxonomic status of Thalmanninella brotzeni Sigal 1948, a species regarded for a long time to be a junior synonym of Th. globotruncanoides, through images of Sigal's type materials deposited at the Musée National d’Histoire Naturelle (Paris), and elucidate the taxonomically important characters that enable unequivocal identification of Th. brotzeni, Th. globotruncanoides and Ps. tehamaensis. Planktonic foraminifera marker species from Mont Risou are compared with well-preserved specimens from Blake Nose Plateau (ODP 171B, North Western Atlantic Ocean) to verify the reliability and stratigraphic distribution of these marker taxa outside the Mediterranean Tethyan area

The global bio-events at the Cenomanian-Turonian transition in the reduced Bahloul Formation of Bou Ghanem (central Tunisia)

In central Tunisia, the thickness of the Bahloul Formation varies generally between 20 to 40 m such as for example, respectively, at wadi Smara near Kalaat Senan and at wadi Bahloul near Maktar. The thickness is also of several tens metres at Koudiat el Azreg near Jerissa and at Tajerouine. In these sites where the thickness of the Bahloul Formation is dilated, in addition to five geochemical events (δ¹³C), nine bio-events were defined near the Cenomanian-Turonian transition, successively in ascending order: 1. LO Rotalipora cushmani, 2. Heterohelix bio-event, 3. FO Pseudaspidoceras pseudonodosoides, 4. LO P. pseudonodosoides, 5. LO Thalmanninella multiloculata, 6. “filaments” bio-event, Cenomanian-Turonian transition, 7. FO Watinoceras sp., 8. FO Pseudaspidoceras flexuosum, 9. FO Helvetoglobotruncana helvetica. Even though the Bahloul Formation in the Bou Ghanem site is only 7.7 m thick (from which only 2.4 m of laminated black limestones), all nine marker bio-events were recorded, almost in the same order except some small differences. A good number of these bio-events are global as they are also present at Pueblo (Colorado, USA), the stratotype for the base of the Turonian stage. Consequently, at a global scale, it is possible to place the Cenomanian-Turonian boundary with one or several of these bio-events, with a good level of confidence

Volcanic ash layers in the Upper Cretaceous of the Central Apennines and a numerical age for the early Campanian

At Montagna della Maiella and at Gola del Furlo (central Apennines) two discrete layers of bentonic clay are intercalated within the pelagic (Furlo) and turbiditic/pelagic limestones (Maiella) of the Upper Cretaceous basinal succession of the Umbrian basin (Scaglia facies). The bentonite layers are dated by planktonic foraminifera to the Globotruncanita elevata zone, early Campanian, and by calcareous nannofossils to the Aspidolithus parcus zone (CC 18); they fall into the reversed interval of chron 33. Detailed correlation shows the layers to be of exactly the same age. The upper layer is dated by U/Pb on magmatic zircons to 81.67±0.21Ma, an age compatible with the Cretaceous time-scale of Obradovich. The mineralogy of the bentonitic clays is almost pure montmorillonite and contrasts sharply with the clay mineral assemblage of the enclosing pelagic and turbiditic limestones, which is dominated by soil-derived smectite and illite in different proportions. The bentonite seams are interpreted as the submarine alteration products of wind-borne volcanic ashes. They can be followed with only minor changes in thickness over 200km and must be derived from distant volcanic sources and related to extreme volcanic events. A possible source area is present in the Dinarides where Upper Cretaceous subduction-related magmatic rocks are widesprea

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Contribution to the understanding of the Ionian Basin sedimentary evolution along the eastern edge of Apulia during the Late Cretaceous in Albania

Integrated in the peri-Adriatic domain, the Ionian Basin extended along a NW-SE direction during the Late Cretaceous, limited on its sides by the Apulian and the Kruja platforms. The basinal/slope succession was studied in seven outcrops exposed in the Albanian fold-and-thrust belt. Sedimentological investigations, supported by bio- and chronostratigraphy were performed on calcareous Upper Cretaceous hemipelagites, gravity-flow deposits and slumps. The western part of the basin was studied, revealing a strong influence of the Apulian margin, alternatively shedding sediment basinward, by means of a tectonically controlled edge. The Late Albian to Cenomanian period is characterized by the settling of muddy debrites along the margin. A deep basinal environment characterizes this period which prolongs until the Santonian, with no significant influx of the platform basinward. This sedimentary setting abruptly changed at the end of the Santonian, with an important influx derived from both platforms. Coarsening and thickening upward sequences show a progressive increase in sediment shedding during the Campanian. The Late Campanian-Early Maastrichtian period points out a major change on the resedimentation processes with the settling of several slumped units reworking thick sediment packages. The latter can be traced along the Apulian margin, testifying of instabilities along the edge of Apulia

Identification des Pseudomonas sp. par spectrométrie de masse type MALDI-TOF

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Brassica rapa hairy root based expression system leads to the production of highly homogenous and reproducible profiles of recombinant human alpha-L-iduronidase

International audienceThe Brassica rapa hairy root based expression platform, a turnip hairy root based expression system, is able to produce human complex glycoproteins such as the alpha—L—iduronidase (IDUA) with an activity similar to the one produced by Chinese Hamster Ovary (CHO) cells. In this article, a particular attention has been paid to the N‐ and O‐glycosylation that characterize the alpha‐L‐iduronidase produced using this hairy root based system. This analysis showed that the recombinant protein is characterized by highly homogeneous post translational profiles enabling a strong batch to batch reproducibility. Indeed, on each of the 6 N‐glycosylation sites of the IDUA, a single N‐glycan composed of a core Man3GlcNAc2 carrying one beta(1,2)‐xylose and one alpha(1,3)‐fucose epitope (M3XFGN2) was identified, highlighting the high homogeneity of the production system. Hydroxylation of proline residues and arabinosylation were identified during O‐glycosylation analysis, still with a remarkable reproducibility. This platform is thus positioned as an effective and consistent expression system for the production of human complex therapeutic proteins

Age and synchronicity of planktonic foraminiferal bioevents across the Cenomanian – Turonian boundary interval (Late Cretaceous)

The upper Cenomanian – lower Turonian is a key-stratigraphic interval, as it encompasses the Late Cretaceous supergreenhouse and a major perturbation of the global carbon cycle (i. e., Oceanic Anoxic Event 2) as evidenced by a global positive carbon isotope excursion and by the nearly world-wide deposition of organic-rich marine facies. A turnover in planktonic foraminiferal assemblages and in other marine organisms is documented across this stratigraphic interval, but reconstruction of the timing and identification of the cause and effect relationships between environmental perturbations and organism response require a highly-resolved stratigraphic framework. The appearance and extinction levels of planktonic foraminiferal species generally allow accurate intra- and supra-basinal correlations. However, bioevents cannot be assumed to be globally synchronous, because the stratigraphic and geographic distribution of species is modulated by ecological preferences exhibited by each taxon and controlled by oceanic circulation, often resulting in earlier or delayed events in certain geographic areas (i. e., diachronous datums). The aim of this study is to test the synchronicity of the planktonic foraminiferal bioevents recognized across the C/T boundary and to provide the most reliable sequence of events for correlation of low to mid-latitude localities. For this purpose, we have compiled a highly-resolved biostratigraphic analysis of the European reference section for the C/T boundary at Eastbourne, Gun Gardens (UK), and core S57 (Tarfaya, Morocco), and correlated the sequence of bioevents identified with those recorded in other coeval sections available in the literature, including the GSSP section for the base of the Turonian Stage at Rock Canyon, Pueblo (Colorado), where we calculated reliable estimates of planktonic foraminiferal events that are well-constrained by radioisotopically and astrochronologically dated bentonite layers. Results indicate that the extinctions of Thalmanninella deeckei, Thalmanninella greenhornensis, Rotalipora cushmani and "Globigerinelloides" bentonensis in the latest Cenomanian are reliable bioevents for correlation. In addition, our analysis highlights other promising lowest occurrences (LOs) that need to be better constrained by bio- and chemostratigraphy, including the LO of Marginotruncana schneegansi falling close to the C/T boundary. By contrast, the appearance of Helvetoglobotruncana helvetica and of some Dicarinella species, the extinction of anaticinellids and the onset of the "Heterohelix" shift are likely diachronous across low to mid-latitude localities. Finally, our study suggests that different species concepts among authors, different sample size and sampling resolution, as well as species paleoecology are important factors that control the stratigraphic position at which bioevents are identified

Quantitative Profiling of Human Renal UDP-glucuronosyltransferases and Glucuronidation Activity: A Comparison of Normal and Tumoral Kidney Tissues

Renal metabolism by UDP-glucuronosyltransferase (UGT) enzymes is central to the clearance of many drugs. However, significant discrepancies about the relative abundance and activity of individual UGT enzymes in the normal kidney prevail among reports, whereas glucuronidation in tumoral kidney has not been examined. In this study, we performed an extensive profiling of glucuronidation metabolism in normal (n = 12) and tumor (n = 14) kidneys using targeted mass spectrometry quantification of human UGTs. We then correlated UGT protein concentrations with mRNA levels assessed by quantitative polymerase chain reaction and with conjugation activity for the major renal UGTs. Beyond the wide interindividual variability in expression levels observed among kidney samples, UGT1A9, UGT2B7, and UGT1A6 are the most abundant renal UGTs in both normal and tumoral tissues based on protein quantification. In normal kidney tissues, only UGT1A9 protein levels correlated with mRNA levels, whereas UGT1A6, UGT1A9, and UGT2B7 quantification correlated significantly with their mRNA levels in tumor kidneys. Data support that posttranscriptional regulation of UGT2B7 and UGT1A6 expression is modulating glucuronidation in the kidney. Importantly, our study reveals a significant decreased glucuronidation capacity of neoplastic kidneys versus normal kidneys that is paralleled by drastically reduced UGT1A9 and UGT2B7 mRNA and protein expression. UGT2B7 activity is the most repressed in tumors relative to normal tissues, with a 96-fold decrease in zidovudine metabolism, whereas propofol and sorafenib glucuronidation is decreased by 7.6- and 5.2-fold, respectively. Findings demonstrate that renal drug metabolism is predominantly mediated by UGT1A9 and UGT2B7 and is greatly reduced in kidney tumors