The Early Jurassic palynostratigraphy of the Lusitanian Basin,western Portugal

A comprehensive investigation of the Early Jurassic stratigraphical palynology of the Lusitanian Basin in western Portugal was undertaken, with most emphasis placed on dinoflagellate cysts. A total of 214 samples from an upper Sinemurian to upper Toarcian composite section based on six successions were examined. The Sinemurian material examined was barren of dinoflagellate cysts; however, the Pliensbachian and Toarcian successions are characterised by relatively low diversities where Luehndea spinosa, Mancodinium semitabulatum, Mendicodinium microscabratum, Nannoceratopsis gracilis, Nannoceratopsis senex, and Scriniocassis priscus are relatively common and biostratigraphically significant. Luehndea spinosa dominates the lowermost Toarcian (Dactylioceras polymorphum ammonite Biozone), and is an index species. At the base of the Hildaites levisoni ammonite Biozone, the effects of the Toarcian Oceanic Anoxic Event (T-OAE) caused Luehndea spinosa to become extinct. At the same time, dinoflagellate cyst abundance and diversity markedly decreased. After the T-OAE, during the middle and late Toarcian, phytoplankton recovery was prolonged and slow in the Lusitanian Basin. The Luehndea spinosa and Mendicodinium microscabratum dinoflagellate cyst biozones are defined, both of which are subdivided into two dinoflagellate cyst subbiozones.     

SynAggreg: A Multifunctional High-Throughput Technology for Precision Study of Amyloid Aggregation and Systematic Discovery of Synergistic Inhibitor Compounds

Numerous proteins can coalesce into amyloid self-assemblies, which are responsible for a class of diseases called amyloidoses, but which can also fulfill important biological functions and are of great interest for biotechnology. Amyloid aggregation is a complex multi-step process, poorly prone to detailed structural studies. Therefore, small molecules interacting with amyloids are often used as tools to probe the amyloid aggregation pathway and in some cases to treat amyloidoses as they prevent pathogenic protein aggregation. Here, we report on SynAggreg, an in vitro high-throughput (HT) platform dedicated to the precision study of amyloid aggregation and the effect of modulator compounds. SynAggreg relies on an accurate bi-fluorescent amyloid-tracer readout that overcomes some limitations of existing HT methods. It allows addressing diverse aspects of aggregation modulation that are critical for pathomechanistic studies, such as the specificity of compounds toward various amyloids and their effects on aggregation kinetics, as well as the co-assembly propensity of distinct amyloids and the influence of prion-like seeding on self-assembly. Furthermore, SynAggreg is the first HT technology that integrates tailored methodology to systematically identify synergistic compound combinations—an emerging strategy to improve fatal amyloidoses by targeting multiple steps of the aggregation pathway. To this end, we apply analytical combinatorial scores to rank the inhibition efficiency of couples of compounds and to readily detect synergism. Finally, the SynAggreg platform should be suited for the characterization of a broad class of amyloids, whether of interest for drug development purposes, for fundamental research on amyloid functions, or for biotechnological applications.     

Le bassin lacustre miocène de Bes-Konak (anatolie-turquie): Géologie et introduction a la paléontologie des vertébrés

The tertiary lacustrine and marshy facies ofBes-Konak (Ankara-district) has provided a rich fauna of Vertebrates preserved as molds and casts in Diatomites and volcano-sedimentary beds.In this assemblage are: Cyprinid fishes (Leuciscus(P.) etiliusRückert Ulkümen) with among them a new species of Barbus, some Amphibians both Urodela (mature Triturinae) and Anura (larval forms of Pelobates sp. and mature Rana sp.), a Turtle (Chelydridae-Chelydropsis sp.) a Snake (Colubroïde-Colubridae or Viperidae) and Birds (among them a new species of cormorant).According to the others various data resulting from palaebotanical, palynological and structural investigations, this fauna is clearly suggestive of a lower or middle Miocene deposit. It supports readily the climatic features (local sub-tropical microclimate inside a regional hot-temperate context) as invertebrates, macro and microflora and sedimentology had already shown.Once more, it points out the peculiar trophic type of the limnic area of Bes-Konak and its evolution to a well-marked eutrophic condition.     

An ophiuroid trackway from the Lower Devonian Hunsrück Slate, Germany

A new trace fossil, Arcichnus saltatus , from the Lower Devonian Hunsrück Slate, Germany, is interpreted as the trackway of a protasterid ophiuroid, Taeniaster. The trackway consists of a series of horseshoe-shaped impressions, produced by a pair of arms, a feature characteristic of some ophiuroid trackways. This new trace fossil demonstrates that protasterids lived both infaunally and epifaunally.     

Perfused transcapillary smooth muscle and endothelial cell co-culture—a novelin vitro model

Summary As mostin vitro endothelial cell (EC)-vascular smooth muscle cell (SMC) co-culture studies have been performed utilizing static culture conditions, none have successfully mimicked the physical environment of these cellsin vivo. EC covering the inner surface of blood vessels are continuously exposed to a hemodynamically imposed mechanical stress resulting from the flow of blood, while SMC are affected by pressure, a flow-related force acting perpendicular to the surface. We have developed a perfused transcapillary co-culture system that permits the chronic exposure of EC and SMC to physiological shear stresses and pressures. SMC and EC co-cultures were successfully established and maintained in long-term culture (7 wk) on an enclosed perfused bundle of semipermeable polypropylene capillaries. By altering flow rate and/or viscosity, shear stresses of 0.07–20 dyn/cm² can be readily achieved in this system. Electron microscopic analysis revealed that SMC formed multilayers around the outside of the capillaries, whereas EC, subjected to 3 dyn/cm² shear stress, formed an intact closely adherent monolayer lining the capillary lumen. EC and SMC exhibited characteristic ultrastructural and gross morphology. EC were separated from SMC by the capillary wall (pore size 0.5 μm, width 150 μM) and while no direct cell-cell contact was evident some cells were seen to migrate into the capillary wall. Both EC and SMC are exposed to the same culture medium, allowing the interaction of substances released in both directions. Yet separate populations of cells are maintained and can be individually harvested for further analysis. This co-culture system that mimics the architecture and physical environment of the vessel wall should have many potential applications in vascular biology.     

清醒羊低氧性肺动脉高压及逆转中肺血管对外源性血小板活化因子的反应

本实验复制了清醒羊低氧性肺动脉高压（ＨＰＨ）及其逆转模型,动态观察了在ＨＰＨ发生、发展及逆转中肺、体循环对外源性血小板活化因子（ＰＡＦ）的反应。结果表明：（１）ＰＡＦ对清醒羊常氧期、ＨＰＨ及ＨＰＨ逆转期均为一强效应肺血管收缩剂,且呈剂量依赖性;（２）ＨＰＨ期：ＰＡＦ对肺血管加压反应增值百分离较常氧期及ＨＰＨ逆转期低;（３）ＰＡＦ对三期体动脉压、心率无明显影响,却能降低各期心输出量。     

Cortical microtubule involvement in bordered pit formation in secondary xylem vessel elements ofAesculus hippocastanum L. (Hippocastanaceae): A correlative study using electron microscopy and indirect immunofluorescence microscopy

Summary A correlative study, using indirect immunofluorescence microscopy (IIF) of anti--tubulin stained sections and transmission electron microscopy (TEM), gave details of the involvement of cortical microtubules (CMTs) in the development of bordered pits in secondary xylem vessel elements ofAesculus hippocastanum L. In addition, aspects of wall cytochemistry were studied during this process using the Thiéry (PATAg) test, immunolocalization with the monoclonal antibodies JIM5 and JIM7, and a range of other cytochemical procedures. IIF showed that the alternately-arranged pits are pre-figured as perforations within a reticulum of randomly-oriented CMTs before any secondary wall thickening is obvious. Each incipient pit border is subsequently delimited by a circle of CMTs whose diameter decreases as deposition of secondary wall takes place around the perforation. These IIF observations are corroborated by a parallel TEM study. During the period of bordered pit formation, the secondary walls of the cell are lignifying. At maturity, however, the pit membrane is unlignified and continues to stain strongly with the monoclonal antibody JIM5, a marker of primary, juvenile wall. The results are discussed in terms of the relationship of the CMT cytoskeleton with development of bordered pits.Abbrevations BSA bovine serum albumin - CMT(s) cortical micro-tubule(s) - EGTA ethylene glycol-bis-(ß-aminoethyl ether)-N,N,N,N-tetraacetic acid - FITC fluorescein isothiocyanate - IIP indirect immunofluorescence - MAP microtubule-associated protein - mf(s) wall microfibril(s) - MTSB microtubule-stabilising buffer - PATAg periodic acid-thiocarbohydrazide-silver proteinate - PBS Phosphate-buffered saline - PIPES piperazine-N,N-bis-[2-ethylsulphonic acid] - SVS secondary vascular system - TEM transmission electron microscopy     

Le genre leptaenopyxis (brachiopoda,leptaenidae) dans le Devonien du Massif Armoricain (France)

The study of genus LeptaenopyxisHavlicek, 1963 in the Lower Devonian from Armorican Massif allows to recognize four species: Leptaenopyxis kerfornei n. sp., Leptaenopyxis cf. bouei (Barrande), Leptaenopyxis sp. 1 and Leptaenopyxis sp. 2. These species were described, until now, under specific name boueiBarrande, 1848. From this study it follows some biostratigraphical and palaeobiogeographical results for the Armorican Massif and its relations with surrounding areas during Lower Devonian time.     

The differentiation of cytotoxic T lymphocytes in vitro

Summary Previous neurohistological studies have been extended to include the structures contained solely or mainly within the junctional esophageal segment which may play an important role in the sphincter mechanism. The main findings were: 1) a progressive cranio-caudal thickening of the muscularis mucosae; 2) a conspicuous thickening of the circular muscle layer; 3) abundant and close interconnections between the esophageal striated fibres and gastric smooth muscle cells; 4) presence of annulo-spiral elastic fibres coiled around bundles of striated musculature; 5) increase of the intramural nerve component, particularly Auerbach's plexus, which consisted of a continuous nervous layer containing twice as many neurocytes as found in the upper esophageal segments; 6) presence of numerous interconnected motor endplates often possessing ultraexpansional fibres and secondary endplates. The findings are discussed with emphasis on functional correlations in order to attain a unitary morpho-functional view.Abbreviations used LES lower esophageal sphincter - HPZ high pressure zone; mm: muscularis mucosae - CNS central nervous system - CCK-PZ cholecystokinin-pancreozymin Dedicated to Prof. Dr. Wolfgang Bargmann for his fundamental contributions to Comparative Morphology