Nitrogen biogeochemistry of water-agro-food systems: the example of the Seine land-to-sea continuum

As an illustration of the usefulness of the concept of water-agro-food systems, this paper describes the mechanisms behind the nitrogen cascade from agricultural soils to the coastal sea rivers through aquifers, riparian wetlands, rivers and streams and the estuary, for the case study of the Seine river watershed and its receiving coastal sea. It is stressed that the structure of the agro-food system, i.e. the way food production and trade, as well as consumption and waste management are organized, is the main determinant of the quality of ground- and surface water as well as of aquatic ecosystem functioning.

     

Le Paléoenvironnement des chasseursde Terra Amata (Nice,Alpes-Maritimes) au Pléistocène moyen. La flore et la faune de grands mammifères

The «living floors of the Acheulean huntersof Terra Amata are situated in their stratigraphical framework; they are included in a beach ridge and in a dune ascribed to the Mindelian glaciation and followed by a substantial paleosol ascribed to the Mindel-Riss interglacial. Palynological studies made in the deposits of the Middle Pleistocene show a rather great rate of forest-trees. The relative importance of trees growing in cool and wet areas and of thermophilous or typically mediterranean species, in every layers, allows to indicate a succession of climatic oscillations inside of a long and rather mild period. Among large mammals, the absence of any archaic form and of any recently appeared form, does not make it possible neither to confirm nor to exclude the hypothesis of a «Mindelian age for this fauna. The faunistic assemblage likewise corresponds to a temperate climate and a forest environment.     

The gene for the type 1 tumor necrosis factor receptor (TNF-R1) is localized on band 12p13

Summary The gene coding for the type I (p55) tumor necrosis factor receptor (TNF-R1) has been localized on human chromosome 12, band 12p13.2, by in situ hybridisation using a biotinylated genomic probe.     

The gene for the type II (p75) tumor necrosis factor receptor (TNF-RII) is localized on band 1p36.2–p36.3

Summary The gene encoding the type II (p75) tumor necrosis factor receptor (TNF-RII) has been localized on human chromosome 1, band 1p36.2 by nonradioactive in situ hybridization. The gene encoding the type I (p55) TNF-R, which is structurally homologous to the type II (p75) TNF-R, has been previously localized on chromosome 12 band 12p13. Thus, despite their probable common ancestry, the genes for the two TNF-Rs are localized on different chromosomes.     

Facteurs de limitation des populations d'Aphis fabae dans l'ouest de la France

Résumé Dans l'ensemble d'études consacrées aux épizooties àEntomophthoraceae surAphis fabae (Scopoli) en Bretagne, ce travail présente les résultats obtenus de 1972 à 1974 à l'aide d'échantillons importants (100 à 300 plantes). Ces résultats concernent principalementNeozygites fresenii (Now.)Remaudière & Keller. En 1972, les conditions climatiques sont tamponnées et constamment favorables aux mycoses. Le nombre d'aphides sains et d'aphides mycosés suit une évolution exponentielle particulièrement régulière; l'effet (évolution du pourcentage de mycosés) n'en est pas moins très brusque. L'arrivée des mycoses dans la parcelle a lieu en même temps que celle des pucerons, ce qui plaide en faveur d'une contamination exogène à laquelle prendraient part les ailés de différentes espèces. Le début du développement de la maladie n'est pas homogène dans l'espace. Les tout premiers mycosés apparaissent dans n'importe quelle colonie, mais très vite on constate que ce sont les colonies les plus grosses qui comportent le plus de mycosés. Cependant, cette relation, qui reste valable pendant la suite de l'épizootie, est très lache. A un moment donné de son déroulement, quelle que soit la taille des colonies concernées, il y a une large gamme de variabilité dans leur taux de parasitisme. Les formes adultes sont systématiquement plus mycosées que les formes larvaires, mais la différence s'amenuise jusqu'à s'annuler à la fin de l'épizootie. En juillet, selon les années, les pucerons mycosés peuvent ou non former des spores durables; en 1972, seulement 2,6 % d'entre eux en forment, mais la répartition de ces individus dans le champ est très homogène.

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Summary This 4th study on epizootics that occur in the populations of the black bean aphid in Brittany, deals with data obtained between 1972 and 1974 using large samples (100 to 300 plants). The results concern mainlyNeozygites fresenii (Nowak) Remaudière & Keller. In 1972, the weather was not very changeable and always favourable for the fungi (table 1). The number of healthy aphids as well as the number of diseased ones, followed a remarkably regular exponential curve. As a result, the variation of the percentage of dead aphids was very sudden (fig. 1, fig. 2). The disease appeared in the fields at the same time as the aphids themselves; so it is possible to think that several species of winged aphids play a part in the introduction of the 1st inoculum into the field (table 2). At its beginning, the development of the disease was not homogeneous in space (table 4). The foremost diseased aphids could be found in any colony whatever its size, but before long it was found that the biggest colonies contained the greatest number of diseased aphids (table 3). Though this relation remained during the continuation of the epizooty, it was a loose one (table 5). At a given time, within colonies of a given size, the percentage of dead aphids was very variable (fig. 3). The adults (winged and apterae)_were systematically more diseased than the nymphs, but the difference became smaller as time went on, and it finally disappeared at the end of the epizooty (table 6). Some years in July, the diseased aphids could form resting spores; in 1972, 2.6% of them formed resting spores, and the spatial dispersion of these individuals was very regular (table 7).

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Les 3 premiers mémoires de cette étude ont été publiés dansEntomophaga respectivement parRobert, Rabasse & Scheltes (18, 1973, 61–75) parRabasse & Robert (20, 1975, 49–63) et parDedryver (23, 1978, 137–151).     

Human C3 deficiency associated with impairments in dendritic cell differentiation, memory B cells, and regulatory T cells

Primary C3 deficiency, a rare autosomal inherited disease (OMIM 120700), was identified in a 2-year-old male suffering from recurrent pyogenic infections from early infancy with undetectable total complement hemolytic activity (CH50) and C3 values. The nonconsanguineous parents and the two patients' two siblings had 50% normal serum C3 concentration. The molecular abnormality associated a paternal allele coding C3 with the missense mutation p.Ser(550)Pro and an apparently null maternal allele, with production of a defective protein that could no longer be secreted. Vaccination of the child did not induce a long-term Ab response. Accordingly, switched memory IgD(-)CD27(+) B cells were barely detected, amounting to only 2.3% of peripheral blood CD19(+) cells. Cells were significantly defective in stimulating alloreactive responses. The in vitro development of immature dendritic cells and their maturation capacity were greatly impaired, with decreased CD1a expression and IL-12p70 secretion ability. These cells were unable to induce autologous B cell proliferation and Ig secretion in the presence of CD40L and C3. Finally, the regulatory T cell development ability of CD4(+) T cells after CD3 and CD46 activation in the presence of IL-2 was significantly impaired. Thus, the association of important functional defects of dendritic cells, acquisition of B cell memory, and regulatory T cells with human C3 deficiency strongly supports a major role for C3 in bridging innate and adaptive immunity in humans.     

Phylogenetic position and description of a new species of subgenus Mus (Rodentia, Mammalia) from Thailand

Molecular, chromosomal and morphometric analyses of wild-caught mice of subgenus Mus from the central plain of Thailand are presented. These specimens are distinct from all species previously described in the literature. This has led to the characterization of Mus fragilicauda sp. n., a new member of the set of closely related species encompassed by the subgenus . While this species may be considered as a sibling and sympatric species of the Asian M. cervicolor , M. fragilicauda sp. n. is phylogenetically closer to the M. musculus complex of species and to the other European species of Mus .     

Correspondence of High Levels of Beta-Exotoxin I and the Presence of cry1B in Bacillus thuringiensis

Examination of 640 natural isolates of Bacillus thuringiensis showed that the 58 strains (9%) whose supernatants were toxic to Anthonomus grandis (Coleoptera: Curculionidae) produced between 10 and 175 μg of β-exotoxin I per ml. We also found that 55 (46%) of a sample of 118 strains whose culture supernatants were not toxic to A. grandis nevertheless produced between 2 and 5 μg/ml. However, these amounts of β-exotoxin I were below the threshold for detectable toxicity against this insect species. Secretion of large amounts of β-exotoxin I was strongly associated with the presence of cry1B and vip2 genes in the 640 natural B. thuringiensis isolates studied. We concluded that strains carrying cry1B and vip2 genes also possess, on the same plasmid, genetic determinants necessary to promote high levels of production of β-exotoxin I.     

Telomerase regulation in hematological cancers: A matter of stemness?

Human telomerase is a nuclear ribonucleoprotein enzyme complex that catalyzes the synthesis and extension of telomeric DNA. This enzyme is highly expressed and active in most malignant tumors while it is usually not or transiently detectable in normal somatic cells, suggesting that it plays an important role in cellular immortalization and tumorigenesis. As most leukemic cells are generally telomerase-positive and have often shortened telomeres, our understanding of how telomerase is deregulated in these diseases could help to define novel therapies targeting the telomere/telomerase complex. Nonetheless, considering that normal hematopoietic stem cells and some of their progeny do express a functional telomerase, it is tempting to consider such an activity in leukemias as a sustained stemness feature and important to understand how telomere length and telomerase activity are regulated in the various forms of leukemias.