Échinodermes de l'Ordovicien supérieur (Ashgill) de Sardaigne et d'Algérie

Research on the influence of sea level variations on the benthic faunas have been carried out in the Upper Ordovician of Sardinia. Study of the depositional facies and sequence analysis of the upper part (Lower Ashgill) of the Portixeddu Formation led to the identification of the sedimentary environments. Cystoids and crinoids are associated to bryozoans and brachiopods in most levels. The numerical analysis of associations and megaguilds shows that crinoids and cystoids have a higher frequency in the proximal and median facies of the upper offshore. The columnal association characterized by Conspectocrinus celticus and the coronoid Mespilocystites tregarvanicus has been discovered in the upper part of the formation. This material and complementary samples from Upper Ordovician of Sardinia and Kabylia (Algeria) bring additional data on the systematic and show the wide distribution of this fauna outside of the Ibero-armorican domain. The distribution of this echinoderm association supports a palaeogeographical position of the Ibero-armorican domain and Sardinia within the north gondwanan margin during the Lower Palaeozoic.     

Histoire plio-pléistocène des écosystèmes végétaux de Méditerranée sud-occidentale : apport de l’analyse pollinique de deux sondages en mer d’Alboran

The pollen analysis of sediments of two boreholes located in the northeastern Morocco (Nador 1) and in the southeastern Spain (Andalucia G1) has allowed shedding a new light on the vegetation and climate of the North African littoral plains, the Rif Massif and the Betic Range during the Pliocene. The vegetation around the Alboran Sea was open and xeric during the Zanclean, dominated by herbs including subdesertic elements as Calligonum, Lygeum, Nitraria and Neurada. This type of vegetation indicates a dry and hot climate. The southwestern Mediterranean steppes have therefore a climatic character; they existed before the presence and the heavy pressure of Man on the environment. From the Piacenzian, the development, at Andalucia as well as at Nador, of Artemisia and the appearance of some altitude trees such as Cedrus and Cathaya indicate a vegetation change linked to a climatic change. Modifications in the vegetation observed during the same period in northwestern Mediterranean seem to indicate that the vegetation changes observed at Andalucia and Nador are controlled by the appearance of the first arctic glacial-interglacial cycles. The cedar tree appears at Nador only at the end of the Piacenzian, at time of the first cooling, while it has been found punctually in Messinian and early Pliocene sediments of Habibas in Algeria and in Messinian sediments of the Bou Regreg section at Salé in Morocco. The regular presence of Cedar at Bou Regreg during the Messinian, allows supposing that it was present in the Middle Atlas Mountains and that its development was favoured by colder conditions.     

Nouveautés sur la séquence du Pléistocène final et l’Holocène initial dans le versant méditerranéen de la péninsule Ibérique à travers l’industrie lithique

This paper explores the cultural sequence for the period 12,500–9000 BP in the Mediterranean coast of the Iberian Peninsula. According to the traditional division by Fortea, this period starts with the end of the Upper Magdalenian, followed by two facies: the Microlaminar Epipalaeolithic and the Geometric Epipalaeolithic (Filador type), (related to Sauveterrian facies). The data collected in recent years suggest a change or amendment to this previous proposal, which now would be divided into four phases: Final Upper Magdalenian, Early Epimagdalenian, Recent Epimagdalenian and Microlaminar Sauveterroid. This paper discusses each of these periods examining the evolution of the stone tools and concluding that in the Mediterranean coast of the Iberian Peninsula the Magdalenian tradition continues with little changes until the advent of the Mesolithic.     

Paléolithique supérieur et Mésolithique en Méditerranée : cadre culturel

The origin of the Upper Palaeolithic around the Mediterranean was the result of the local evolution, particularly in the Near East and in the Lower Nile basin, and of the migration from this zone to South-Eastern and Central Europe. The Initial Upper Palaeolithic in the Near East belt was the effect of local evolution from the industries based on Levallois concept to the industries which developed leptolithic blade technologies. This evolution is well registered in multi-layer sites in the Syro-Palestinian belt (Emirian/Ahmarian), which was the starting point of the diffusion of these “transitional” industries in South-Eastern and Central Europe. This diffusion could be identified with the migration of first anatomically Modern Humans. The Early Upper Palaeolithic in Europe — dated to the second half of the Interpleniglacial — was, at least partially, based on these “transitional” industries and manifested by the appearance of the Aurignacian, contrasted with local cultures such as the Uluzzian in Mediterranean Europe. During whole the Interpleniglacial Europe was separated from Northern Africa dominated by local evolution of Middle Palaeolithic (Middle Stone Age) cultures (mostly expressed by the Aterian), and by specific “transitional” industries on the southern Mediterranean coast (Early Dabbian) and in the Lower Nile basin. The Last Glacial Maximum and the corresponding sea level recession opened new possibilities of contacts between the Maghreb and the Iberian Peninsula in both directions (Aterian-Solutrean and Gravettian-Early Iberomaurusian), which are still difficult to be proved before new chronostratigraphic correlations are made. At the same time we register links between south-eastern Europe and western Anatolia; the real border between Near Eastern and European Mediterranean cultural zones was marked, in the Late Glacial, by the Taurus chain. During the Late Glacial the cultural separation between Europe and Africa was particularly marked. Only in the Aegean basin the first sea navigation facilitated contacts which become widespread as late as in the Early Holocene with neolithization trough maritime contacts.     

A phylogenetic analysis of basal Anseriformes, the fossil Presbyornis, and the interordinal relationships of waterfowl

A phylogenetic analysis of 123 morphological characters of basal waterfowl (Aves: Anseriformes) and other selected avian orders confirmed that the screamers (Anhimae: Anhitn-idae) are the sister-group of other waterfowl (Anseres), and that the magpie goose (Anseranatidae: Anseranas semipalmata) is the sister group of other modern waterfowl exclusive of screamers (Anatidae sensu stricto). The analysis also supports the traditional hypothesis of the gallinaceous birds (Galliformes) as the sister group of the Anseriformes. Presbyornis, a fossil from the early Eocene of Wyoming and averred by Olson & Feduccia as showing that the Anseriformes were derived from shorebirds (Charadriiformes), was found to represent the sister group of the Anatidae. Associated hypotheses by Olson & Feduccia concerning the implications of Presbyornis for the phylogenetic relationships of flamingos (Phoenicopteriformes), the position of the Anhimidae within the waterfowl, relationships among modern Anatidae, and a plausible evolutionary scenario for waterfowl also are rejected. Analyses revealed that cranial characters were critical to the establishment of the Galliformes as the sister group of the Anseriformes; exclusion of the Anhimidae, especially in combination with Anseranas, also undermined the support for this inference. Placement of Presbyornis as the sister group of the Anatidae casts doubt on the role suggested by Feduccia of ‘transitional shorebirds' in the origin of modern avian orders, and calls into question the concept of ‘fossil mosaics’. The phylogenetic hypothesis is used to reconstruct an evolutionary scenario for selected ecomorphological characters in the galliform-anseriform transition, to predict the most parsimonious states of these characters for Presbyornis, and to propose a phylogenetic classification of the higher-order taxa of waterfowl. This re-examination of Presbyornis also is used to exemplify the fundamental methodological shortcomings of the intuitive approach to the reconstruction of phylogenetic relationships.     

Foliar sclereids in the Magnoliaceae

The foliar sclereids in 136 species representing 11 of the 12 genera of Magnoliaceae were studied and compared. Sclereids occur in four different cell assemblages within the leaf: diffuse idioblasts, mesophyll, dermal system, and the vein sheath including terminal elements. Tropical members tend to have the most highly sclerified leaves. In species of Manglietia the leaves have sclerified spongy mesophyll and either sclerified epidermis or hypodermis. In Talauma , sclerification affects the vein sheath and terminal cells of veinlets, with a specialized thick marginal vein in the Asian taxa but not in the American ones. Liriodendron and the magnolias native to the north temperate zone have only minimal sclerification, which usually is confined to the vein sheath of the midrib and the main lateral veins, and as idioblastic sclereids in the petiole and the midrib near the base of the blade. The two largest genera Magnolia and Michelia are heterogeneous and include species which vary as to their combinations of sclerified elements among the four possible types.     

Inception of the Modern Public Health System in China and Perspectives for Effective Control of Emerging Infectious Diseases: In Commemoration of the 140th Anniversary of the Birth of the Plague Fighter Dr. Wu Lien-Teh

In this article, we systematically review Dr. Wu Lien-Teh's academic achievements and outstanding contributions in the prevention and control of the plague epidemic in northeast China and introduce the development of the earliest public health epidemic prevention system in China in order to commemorate the 140th anniversary of Dr. Wu Lien-Teh's birth. We hope that this article will provide insights into the effective prevention and control of emerging infectious diseases as well as the current worldwide pandemic of COVID-19, facilitating the improvement and development of public health systems in China and around the globe.     

Early embryonic development of the mayfly Ephemera japonica McLachlan (Insecta: Ephemeroptera,Ephemeridae)

In the newly laid egg of the mayfly Ephemera japonica, an egg nucleus (oocyte nucleus) at metaphase of the first maturation division is in the polar plasm at the mid-ventral side of the egg, and a male pronucleus lies in the periplasm beneath a micropyle situated just opposite the polar plasm or at the mid-dorsal side of egg. The maturation divisions are typical. An extensive and circuitous migration of the male pronucleus is involved in the fertilization process: it first moves anteriad in the periplasm from beneath the micropyle to the anterior pole of the egg and then turns posteriad in the yolk along the egg's long axis to the site of syngamy, near the center of the egg. Cleavage is superficial. The successive eight cleavages, of which the first five are synchronized, result in the formation of the blastoderm, and about ten primary yolk cells remain behind in the yolk. Even in the newly formed blastoderm, the thick embryonic posterior half and the thin extraembryonic anterior half areas are distinguished: the former cells are concentrated at the posterior pole of the egg to form the germ disc, and the latter cells become more flattened, forming serosa. Time-lapse VTR observations reveal a yolk stream that is in accord with the migration of the male pronucleus in time and direction. The yolk stream is also generated in activated unfertilized eggs, and it is probable that the migration of the male pronucleus in association with the fertilization may be directed by the yolk stream. J. Morphol. 238:327–335, 1998. © 1998 Wiley-Liss, Inc.     

Transcriptomic Analysis of Human Retinal Surgical Specimens Using jouRNAl

Retinal detachment (RD) describes a separation of the neurosensory retina from the retinal pigmented epithelium (RPE). The RPE is essential for normal function of the light sensitive neurons, the photoreceptors. Detachment of the retina from the RPE creates a physical gap that is filled with extracellular fluid. RD initiates cellular and molecular adverse events that affect both the neurosensory retina and the RPE since the physiological exchange of ions and metabolites is severely perturbed. The consequence for vision is related to the duration of the detachment since a rapid reapposition of the two tissues results in the restoration of vision ¹. The treatment of RD is exclusively surgical. Removal of vitreous gel (vitrectomy) is followed by the removal non essential part of the retina around the detached area to favor retinal detachment. The removed retinal specimens are res nullius (nothing) and consequently normally discarded. To recover RNA from these surgical specimens, we developed the procedure jouRNAl that allows RNA conservation during the transfer from the surgical block to the laboratory. We also standardized a protocol to purify RNA by cesium chloride ultracentrifugation to assure that the purified RNAs are suitable for global gene expression analysis. The quality of the RNA was validated both by RT-PCR and microarray analysis. Analysis of the data shows a simultaneous involvement of inflammation and photoreceptor degeneration during RD.     

Rice bronzing in Nigeria caused by nutrient imbalances and its control by potassium sulfate application

Rice plants with bronzing, collected from fields in central and southern Nigeria, where the soils consisted of Tropaquent, Tropaquult and Tropaquept, showed higher iron and lower potassium, phosphorus, and magnesium concentrations than plants with little or no bronzing. Pot experiments with the soils indicated that the severity of the bronzing was affected not only by the iron concentration in the shoots but also by the potassium concentration. The application of chloride compounds to the soil increased severity of the bronzing and lead to deterioration of growth, whereas the application of sulfate compounds was beneficial.The application of potassium sulfate reduced the severity of bronzing and increased the dry matter production of rice plants grown in the field. The concentration and accumulation of potassium in the shoots increased when the bronzing severity decreased and the iron concentration was decreased by the dilution effect caused by the increased dry matter production.     

Madonna dell'Arma (San Remo, Italie) : expression locale de la végétation ligure au cours du Paléolithique moyen

Pollen analysis of Madonna dell’Arma cave inside part (Liguria, Italy) allowed us to reconstitute, at local scale, the Ligurian coastal vegetation between the end of the last interglacial period and the beginning of the pleniglacial. This transition period shows an important representation of arboreal cover and a persistence of thermophilous elements that allowed us to considerate the western Liguria as a periglacial refuge. During the end of the last interglacial, xerophytic, halophytic herbs and shrubs taken over from a Mediterranean pre-forest unit in the first slopes constituted the coastal zone. The nearness of Argentina torrent and the Armea influenced, in the coast, the existence of marshy zones colonized by hygrophilous trees. In the Ligurian lowlands spread out sclerophyllous and mesophilous forests according to altitude. The beginning of the pleniglacial is indicated in the sequence by increases of Pinus, Cupressaceae and Artemisia in the context of a decline in the thermophilous components. This picture of vegetation has become integrated into the multidisciplinary studies of the site and contributed to the elaboration of palaeoclimatic hypothesis similar as those revealed by the fauna.     

Le Lias et le Dogger du sud du Bassin parisien (France) : rôle de la tectonique syn-sédimentaire et reconstitutions paléogéographiques à l'échelle de la biozone d'ammonite

The Lias and Dogger series in the southern Paris Basin outcrops are precisely dated following the ammonite biozonation scale. In these series, the depositional environment context is accurately identified and thus various isopic zones can bee recognized. From the outcrop study, the depositional sequence and the tectonics events are also distinguished. The poorly dated subsurface data should be not anymore interpreted as diagraphic signatures, with the traditional peak to peak correlation. They now need to be analysed according to the geodynamic evolution of each isopic zone. The Liassic transgressive series (in the Armorican continent) and the Dogger platforms numerous carbonate bodies are correlated at biostratigraphic scale, throughout the whole southern Paris Basin. Subsequently, paleogeographic maps are established and based on depositional sequences. The basin evolution image changes radically. This shows clearly that the complexes carbonate bodies layout prohibits any depositional environment interpretation and any isopach mapping at geological stage level. If not, the carbonate platforms of different age would be amalgamated, without any connection with the reality. Over the time, paleogeographic maps show syn-sedimentary short wavelength deformations, more or less well expressed according to the local sedimentary context. During the Lias and the Dogger, three steps can be distinguished in the southern Paris Basin. Hettangian to Lower Aalenian, the progressive increase in accommodation drives to total immersion of the continental areas; the maximum of accommodation during the Middle Toarcian entails uniform sedimentary conditions. However, short wavelength deformations persist. The major accidents defining the isopic zones are mainly North-South oriented. Middle Aalenian to Middle Bathonian, isopic zones are contrasted, controlled by the North-South accidents but also the North West-South East ones ; the variable accommodation allowed the development of regional sedimentary gaps and shallow limestone progradations on a marly area (so called “Sillon marneux”) ; tectonics events correspond to the Tethyan and the North Sea riftings influences. Upper Bathonian to Upper Oxfordian, the North West-South East tectonics accidents are particularly active; this tectonic phase could be associated to the thermal event, described in the Paris Basin and announcing the Malm depositional environment.     

人工合成多样性突变文库研究进展*

突变文库的构建是定向进化研究过程中一个关键步骤,主要利用天然存在的系统或者人工合成的分子技术来产生多样性核酸分子文库,为制备和筛选具有一定特性的蛋白酶、多肽、人工抗体等提供庞大的遗传基因库,也可用于合成生物学中相关基因元件的研究与筛选,为目标生物制品的高效工业化生产提供动力。随着对突变文库构建技术研究的日益深入,各种文库构建策略相继被开发出来,并在生物能源、生物化工、生物医药、生物试剂和食品工业等方面得到了广泛的应用。然而,定向进化中的文库构建策略多有不同,各种突变文库构建技术的核心方法也在不断创新。主要介绍近年来实验室中人工合成多样性文库的前沿技术,并对文库构建技术在自动化和智能化方向的发展进行了展望。     

Tick saliva: recent advances and implications for vector competence

Abstract . Secretions of the tick salivary glands are essential to the successful completion of the prolonged feeding of these ectoparasites as well as the conduit by which most tick-borne pathogens are transmitted to the host. In ixodid ticks the salivary glands are the organs of osmoregulation, and excess water from the bloodmeal is returned via saliva into the host. Host blood must continue to flow into the feeding lesion as well as remain fluid in the tick mouthparts and gut. The host's haemostatic mechanisms are thwarted by various anti-platelet aggregatory, anticoagulatory and anti-vasoconstrictory factors in tick saliva. Saliva components suppress the immune and inflammatory response of the host permitting the ticks to remain on the host for an extended period of time and, adventitiously, enhancing the transmission and establishment of tick-borne pathogens. Over the years much work has been done on the numerous enzyme and pharmacological activities found in the tick saliva. The present article reviews the most recent work on salivary gland secretionith special emphasis on how they favour pathogen transmission.     

Figurations de l’amas stellaire des Pléiades sur deux roches gravées de la région du Mont Bego Z IX. GII. R 4 et Z IX. GIII. R 6

Two engraved rocks are situated 140 m from each other at an altitude of about 2250 m. One of them is called “female dancer”, and the other, “the Pleiads”, and both show a group of seven small pitted areas, of which one is smaller than the others and ‘ identified as the “Pleiads stellar cluster”, often depicted or mentioned during Antiquity and also throughout various historical periods.On each of these rocks, a large halberd, whose handle is oriented east-west, was traced along a natural fissure in the rock and engraved in the center of the composition. The “Pleiads stellar cluster” is represented on each of the two rocks beside the halberd : although situated to the west above the halberd blade on the “female dancer” rock, it is placed to the south and to the left of the halberd handle on “the Pleiads” rock. This difference may mark two distinct calendar data.The position of the different figures in the compositions illustrated on these two rocks, in particular inversions in the representation of some of them may indicate two distinct periods of the agricultural yearly cycle: on the rock called “female dancer”, the “heliacal raise” at summer's end, marking the beginning of the harvest and, on the rock called “the Pleiads”, the “heliacal setting”, just before winter, after the end of the harvest, when the rains soaks the ground and it is time to plow.     

On the homology of the scales in Gunnera (Gunneraceae)

In the genus Gunnera , the species of subgenus Panke are unique in having large, triangular scales between the leaves on the rhizomes. The morphological significance of these scales has been extensively debated in the past. They have been interpreted as stipules, ligules, or cataphylls, with attempts made to identify homologous structures in representatives of the other subgenera. In the stoloniferous subgenus Misandra, the shoot apex is covered by a hoodlike structure, usually termed ochrea, generally considered homologous to the scales in Panke . Efforts to find similar structures in the remaining subgenera were unsuccessful. Due to the lack of a phylogenetic hypothesis, the homology of the scales has remained unresolved. In this study, the shoot apices of species from all subgenera were examined by light and scanning electron microscopy and the results interpreted in a phylogenetic context. The tip of the stolons in subgenera Pseudogunnera and Milligania carries two opposite cataphylls at the base of the new shoot. These are homologous to the ochrea in Misandra which is in turn homologous to the scales in Panke ; the latter are thus neither stipules nor ligules but cataphylls. The stems of subgenera Ostenigunnera and Gunnera have no similar structures. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142 , 301−308.     

Revised Crystal Structure of Human Adenovirus Reveals the Limits on Protein IX Quasi-Equivalence and on Analyzing Large Macromolecular Complexes

We report the revised crystal structure of a pseudo-typed human adenovirus at 3.8-Å resolution that is consistent with the atomic models of minor proteins determined by cryo-electron microscopy. The diffraction data from multiple crystals were rescaled and merged to increase the data completeness. The densities for the minor proteins were initially identified in the phase-refined omit maps that were further improved by the phases from docked poly-alanine models to build atomic structures. While the trimeric fiber molecules are disordered due to flexibility and imposition of 5-fold symmetry, the remaining major capsid proteins hexon and penton base are clearly ordered, with the exception of hypervariable region 1 of hexons, the RGD containing loop, and the N-termini of the penton base. The exterior minor protein IX together with the interior minor proteins IIIa and VIII stabilizes the adenovirus virion. A segment of N-terminal pro-peptide of VI is found in the interior cavities of peripentonal hexons, and the rest of VI is disordered. While the triskelion substructures formed by the N-termini of IX conform to excellent quasi 3-fold symmetry, the tetrameric coiled-coils formed by the C-termini and organized in parallel and anti-parallel arrangement do not exhibit any quasi-symmetry. This observation also conveys the pitfalls of using the quasi-equivalence as validation criteria for the structural analysis of extended (non-modular) capsid proteins such as IX. Together, these results remedy certain discrepancies in the previous X-ray model in agreement with the cryo-electron microscopy models.     

L’habitat en grotte au Néolithique : vers une estimation de l’intensité des occupations

The archaeological excavation of the cave of the Gardon has brought to light a dilated and nearly continuous stratigraphy for the Neolithic era. The analysis of lithic industry has showed the existence of variations between those neolithic layers, which are independents of the technological processes of tools productions. Four criteria allow us to characterize the occupation’s type of each layer. Compared to the excavations data and to sedimentological analysis, these results allow us to display the evolution of the intensity of occupations of the cave throughout the whole Neolithic.     

Evidence of Host Discrimination by Microctonus hyperodae Loan (Hymenoptera: Braconidae, Euphorinae), a Parasitoid of the Argentine Stem Weevil Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae)

Microctonus hyperodae is a solitary endoparasitoid of the Argentine stem weevil, Listronotus bonariensis. Early investigation into the biology of the parasitoid indicated that there was no discrimination between parasitized and unparasitized hosts. However, dissection data from two experiments were analyzed according to three mathematical models. Model I was based on the Poisson distribution and assumed random selection of hosts. The host discrimination model (model II) assumed that parasitized hosts had reduced attractiveness to searching parasitoids. A competition model (model III) made the assumption that competition between the early immature parasitoid stages led to premature mortality, which was not accounted for in the dissection results. The dissection data indicated statistically significant departure from the Poisson model. Results from the laboratory experiment indicated that host discrimination explained the results more accurately than parasitoid larval competition. Models II and III both provided adequate fits to the field data, although the departure from the observed data was greatest for the competition model. Both intra- and inter-ecotypic host recognition were evident, and there was some indication that clonal recognition took place. This is the first evidence of host discrimination by a member of the genus Microctonus. It has provided further indication of the success of M. hyperodae as a biological control agent.     

Kinetic analysis of a general model of activation of aspartic proteinase zymogens

Starting from a simple general reaction mechanism of activation of aspartic proteinase zymogens involving an uni- and a bimolecular simultaneous route, the time course equation of the concentration of the zymogen and of the activated enzyme have been derived. From these equations, an analysis quantifying the relative contribution to the global process of the two routes has been carried out for the first time. This analysis suggests a way to predict the time course of the relative contribution as well as the effect of the initial zymogen and activating enzyme concentrations, on the relative weight. An experimental design and kinetic data analysis is suggested to estimate the kinetic parameters involved in the reaction mechanism proposed. Finally, we apply some of our results to experimental data obtained by other authors in experimental studies of the activation of some aspartic proteinase zymogens.