Les Ostracodes de la partie supérieure de la Formation deTeferguenite (Givétien) et de la Formation de Marhouma (Givétien-Famennien) de la coupe du km 30 (Saoura,Sahara algérien)

More than fifty ostracod species, twenty-two of which are Entomozoacea, have been identified in the upper part of the Teferguenite Formation and in the Marhouma Formation. The zonal sequence established on the Entomozoacea is applicable to the Frasnian and the Famennian of the Algerian Sahara; seven zones are recognized. One new species, Tubulibairdia marhoumaensis nov. sp., is described.     

Cloning of the spoT Gene of “Candidatus Phlomobacter fragariae” and Development of a PCR-Restriction Fragment Length Polymorphism Assay for Detection of the Bacterium in Insects

Marginal chlorosis is a new disease of strawberry in which the uncultured phloem-restricted proteobacterium “Candidatus Phlomobacter fragariae” is involved. In order to identify the insect(s) vector(s) of this bacterium, homopteran insects have been captured. Because a PCR test based on the 16S rRNA gene (rDNA) applied to these insects was unable to discriminate between “P. fragariae” and other insect-associated proteobacteria, isolation of “P. fragariae” genes other than 16S rDNA was undertaken. Using comparative randomly amplified polymorphic DNAs, an amplicon was specifically amplified from “P. fragariae”-infected strawberry plants. It encodes part of a “P. fragariae” open reading frame sharing appreciable homology with the spoT gene from other proteobacteria. A spoT-based PCR test combined with restriction fragment length polymorphisms was developed and was able to distinguish “P. fragariae” from other insect bacteria. None of the many leafhoppers and psyllids captured during several years in and around infected strawberry fields was found to carry “P. fragariae.” Interestingly however, the “P. fragariae” spoT sequence could be easily detected in whiteflies proliferating on “P. fragariae”-infected strawberry plants under confined greenhouse conditions but not on control whiteflies, indicating that these insects can become infected with the bacterium.     

L’évolution du cerveau se poursuit

After the strong climatic shocks which happened over and over again, which made the hands free and which started the biological and cultural development of Hominoids, everything depended on the brains of the species concerned and their ability to correlate and invent, because of the constant pressure of their natural and social environment. We are less interested in describing 15 steps here, than in specifying, for each reference mark in a non-stop process, the level reached by mental ability as much cognizantly as affectingly and the neurological bases, which allowed them to occur. This progression was based on the complexification (through epigenesis) of intracerebral connections at different levels allowing us to have large conscience and language, which are the bases of our freedom (via feelings, re-entries and mental pictures). Consequently, men could progressively have control of natural powers, inert ones first (tools), then moving ones (fire), living (hunting) and social ones (slavery); at last, men could free himself from them and perceive them objectively, dominate them, and conceive them in time and abstraction. Writing, then philosophy, then counting and logic have only recently crowned the progress towards the conquest of abstract and humanism through reversive action. The whole show phyletical gradualism, which is still progressing.     

Gravures et abstraction: Les gravures non figuratives de Roc-la-Tour I, le schiste gravé des Beaux-Sarts et les progrès de l’abstraction durant la Préhistoire et l’Histoire

Beyond the 75 animal and human pictures, the 491 Magdalenian engraved plaquettes bear 410 abstract signs, in 14 different types, among which eight were unknown up to now in South-Western France, (more than 130 cases). Some examples of all those signs are shown. Besides there are 213 groups of parallel lines. At “Les Beaux-Sarts”, less than 2 m from the hut described in 2003, another human excavation (maybe a tomb?) delivered a schist plaquette with 94 parallel lines carved on its surface, the lines appear as three groups of 14, 7 (or 8?) and 24 (or 28?) lines and one group of 17 (or 18?) oblique lines, with various secondary lines. Five thousand years before the cerebral center of precise calculation was at the beginning of its formation, this piece, out of the bases of which calculation might be subdivided, cannot be considered as the evidence that they were able to count. The author analyses the affective mental possibilities proved by those elements and puts them apart from the rational progress in the abstraction possibilities of the human brain, which occurred later all through ten thousand years.     

Quand désarticuler laisse des traces : le cas de l’hyperextension du coude

In this paper, we try to document butchery practices from the past. We attempt to characterize through experimental data the marks produced when dismembering using overextension of the elbow of Sheep and several bird species. For birds, the experimentation was realized with uncooked carcasses. In many cases, overextension produced break down of the olecranon fossa of the humerus, with medial wrench of the distal part. Moreover, the proximal joints of the radius and ulna are broken. Bony and uncooked forelimb Sheep bones have been dismembered by overextension. Observations were noticed only on the radio-ulnar. The ulnas had a negative wear scar up to the anconeus process. Sometimes, these marks are associated with lateral crushing of the bone. In the second part of the article, we compare our experimental data with archaeological material. Although we found many cases of dismembering by overextension on bird bones, no data were found on small ungulates material.     

Differentiation between clathrin-dependent and clathrin-independent endocytosis by means of membrane fluidity measurements

The fluorescence probe [1-(4-trimethylammonium]-6-phenyl-1,3,5-hexatriene (TMA-DPH) displays properties relevant for both monitoring endocytosis kinetics and assessing membrane fluidity by fluorescence-anisotropy measurements (1). Thus, it is, possible with this probe to follow the evolution of membrane fluidity during endocytosis, from the very beginning of the process, i.e., the formation of endocytic vesicles. In most cases, endocytosis is known to start with clathrin-coated vesicles. Still, there are more and more arguments in favor of a complementary endocytic pathway without clathrin. In this article we present membrane-fluidity data for very early endocytosis, which allow an upper limit to be determined for the contribution of a putative nonclathrin pathway. We show that this limit is markedly higher for bone marrow-derived macrophages than for mouse fibroblasts of the L929 cell line.     

Roc-La-Tour I, le site des Esprits : L’art du Magdalénien VI à Monthermé (Ardennes)

For 100 or 200 years during the late Bölling this site in the Ardenne, with its fine outlook, was the summer camp for a small group (10-15 persons) from the Paris Basin. No bone has been preserved (acid soil). Each of the four levels corresponds to at least five to 10 visits. The visitors were attracted to the site by the viewpoint, the dry ground and the presence of ochre and schist. Thousands of plaques and plaquettes were used and broken up before and after engraving. There are more engraved pieces than burins and borers: the visitors must have engraved every day. The engravings include five palimpsests, 32 tangled groups of incisions (« tangles ») and 75 fragmentary images of animals and human beings, with the same menagerie as in the South-West of France; a large majority of the figurative subjects are shown only partially, or merely roughly sketched; there are several human beings and one vulva. The 410 abstract signs can be classified into 14 categories, mostly different from those found in the South-West, and there are 215 groups of parallel lines. These engraved, smoothed or shaped plaquettes, together with 123 deposits of ochre, all contrast with the lack of similar finds on sites in the Paris Basin which are, however, 10 times richer as far as tools are concerned. There was an evolutionary course in the engravings (figures and signs): inception, development, acme and the start of a decline. This site complements those in the Paris Basin and the Ardenne left by the same persons; it is an integral, inseparable part of the remains of the same group of human beings.     

Interactions of the monomeric and dimeric flavones apigenin and amentoflavone with the plasma membrane of L929 cells; a fluorescence study

Flavonoids are ubiquitous polyphenolic compounds, found in vascular plants, which are endowed with a large variety of biological effects. Some of these effects have been assumed to result from interactions with the cell plasma membrane. In order to investigate the nature of these interactions a fluorescence study was performed with two flavonoids, currently used in one of the laboratories: apigenin and its homologous dimer amentoflavone. After preliminary assays with DPH in several types of phospholipid liposomes, the effects of these flavonoids on the membrane of mouse L929 fibroblasts were compared, using the non-permeant probe TMA-DPH. Amentoflavone, unlike apigenin, induced a static quenching effect, which denoted an important, but reversible, association of the molecule with the plasma membrane. In addition, amentoflavone treatment induced a dose-dependent increase in TMA-DPH fluorescence anisotropy, which could be interpreted as an increase in membrane lipidic order. For apigenin, the effect was much less important. Moreover, exploiting the capacity of TMA-DPH to label endocytic compartments, it was shown that, after association with the membrane, amentoflavone is not internalized into the cell. Possible correlations of these membrane effects with other biological properties are discussed.     

The influence of microtubule integrity on plasma membrane fluidity in L929 cells

The aim of this work was to examine the possible influence of the integrity of the microtubule network on the plasma membrane fluidity of L929 mouse fibroblasts. The L929 cell line was selected for the ease of culture and the stability of its characteristics. The cells were treated with colchicine, nocodazole and vinblastine, three microtubule-depolymerizing drugs, at various concentrations and for various times. Membrane fluidity was assessed from fluorescence depolarization measurements with the plasma membrane probe TMA-DPH. Each of the drugs induced a significant, dose-dependent decrease in fluorescence anisotropy. The effect levelled off (5-7% decrease) after ~ 90 min of treatment, and could be unambiguously interpreted as resulting from an increase in membrane fluidity. The cumulative action of the drugs did not significantly increase the effect. The effects of colchicine and nocodazole could be reversed by incubation in drug-free medium, but not that of vinblastine. The results are discussed in correlation with the kinetics of the three drugs interaction with tubulin or microtubules. It is concluded that the microtubule integrity contributed to the high plasma membrane lipidic order, but less than other factors, like the lipid composition and the cholesterol content.