Présence de l’éocrinoïde Ascocystites Barrande (Echinodermata,Blastozoa) dans l’Ordovicien supérieur (Caradoc) de l’Anti-Atlas (Maroc) : premières données

Family Ascocystitidae, defined and established by Georges Ubaghs in 1967, includes a single genus, Ascocystites. This genus was described and figured for the first time by Barrande in 1887, from Bohemian specimens. Thereafter, specimens brought close to Ascocystites or assigned to this genus were described starting from samples collected in Bohemia in the Armorican Massif or in Portugal. The new specimens were collected in Morocco in the Eastern Anti-Atlas, within the formation of Izzeguirene of Caradoc age. The studied material includes several sandy slabes often containing many well-preserved and almost complete individuals. These levels gather individuals of various sizes, corresponding to various stages of development. The morphological study in progress should allow a specific attribution by comparison with the Bohemian and Armorican forms actually known. The Moroccan material has, in addition, the advantage of corresponding to associations of several Echinodermata groups, rich in individuals, allowing a taphonomic and possibly paleoenvironmental study. Biostratigraphically, Ascocystitidae are actually known between Middle (Armorican Massif and Portugal) and Upper Ordovician (Bohemia and now Morocco). The discovery of Ascocystitidae in the Moroccan Anti-Atlas extends their distribution, within gondwanian domain, during Middle and Upper Ordovician.     

An enzymatically produced novel cyclomaltopentaose cyclized from amylose by an alpha-(1-->6)-linkage, cyclo-{-->6)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->}

A bacterial strain AM7, isolated from soil and identified as Bacillus circulans, produced two kinds of novel cyclic oligosaccharides. The cyclic oligosaccharides were produced from amylose using a culture supernatant of the strain as the enzyme preparation. The major product was a cyclomaltopentaose cyclized by an alpha-(1-->6)-linkage, cyclo-{-->6)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->}. The other minor product was cyclomaltohexaose cyclized by an alpha-(1-->6)-linkage, cyclo-{-->6)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->}. We propose the names isocyclomaltopentaose (ICG5) and isocyclomaltohexaose (ICG6) for these novel cyclic maltooligosaccharides having one alpha-(1-->6)-linkage. ICG5 was digested by alpha-amylase derived from Aspergillus oryzae, cyclomaltodextrin glucanotransferase (CGTase) from Bacillus stearothermophilus, and maltogenic alpha-amylase. On the other hand, ICG6 was digested by CGTase from B. stearothermophilus and B. circulans, and maltogenic alpha-amylase. This is the first report of enzymatically produced cyclomaltopentaose and cyclomaltohexaose, which have an alpha-(1-->6)-linkage in their molecules.     

Possible antagonism of (Z)‐2‐hexenyl (E)‐3‐hexenoate against the attractiveness of (E)‐2‐hexenyl (Z)‐3‐hexenoate to Ooencyrtus nezarae (Hymenoptera: Encyrtidae)

Ooencyrtus nezarae (Hymenoptera: Encyrtidae) is an egg parasitoid of bean bug Riptortus pedestris (Hemiptera: Alydidae) which is a major pest of beans. Females of O. nezarae are attracted to (E)‐2‐hexenyl (Z)‐3‐hexenoate (EZ), one of the components of aggregation pheromone of R. pedestris. Effects of three isomers (ZE, EE and ZZ) of EZ on the attractiveness of O. nezarae were tested using electroantennography (EAG) and field bioassays. EAG analyses revealed that the response of O. nezarae to ZE was significantly higher than those to air, hexane and two other isomers, even though the response was lower than that to EZ. ZE affected the attractiveness of EZ dose‐dependently in the field. Addition of ZE (100 mg) to EZ (10 mg) caused a significant reduction in the catches of O. nezarae females. Single or binary addition of two other isomers (EE and ZZ) to EZ could not decrease or increase significantly the number of O. nezarae catches of EZ. Even though addition of ZZ (10, 50 or 100 mg) to EZ (10 mg) caused dose‐dependent reduction in the number of O. nezarae female catches, the reductions were not significantly different from that of EZ. EZ and its three isomers were not attractive to O. nezarae males at all.     

Nouveau matériel de Leptobos (Smertiobos) crassus (Artiodactyla, Mammalia) du Pléistocène inférieur à Renzidong (Chine de l’Est)

New remains of Leptobos (Smertiobos) crassus have been identified among the fossils excavated from a new early Pleistocene site at the Renzidong in Anhui Province, Eastern China. It is a Leptobos bearing frontal appendices with a simple curvature and its distal part turns higher than the other species of the subgenus. The present study shows that the first appearance of Leptobos in China is in the zone equivalent to the European MNQ 16b, later than its first appearance in Western Europe (MNQ 16a); and the genus Leptobos can serve as index fossil of the lower Pleistocene in China (2.5-0.78 Ma, Chinese definition).     

Variations morphologiques des Toxaster (Echinoida : Spatangoida) en regard des fluctuations spatiales (Arc de Castellane, SE France) et temporelles (Valanginien-Hauterivien) du milieu sédimentaire : expression d'un potentiel adaptatif restreint

The impact of sedimentary conditions on the settlement, growth, and morphology of primitive spatangoid sea urchins of the genus Toxaster from the Lower Cretaceous (Valanginian and Hauterivian of the Provencal platform) is analyzed. The analyses concern spatial and temporal patterns of variation. The spatial approach is based on six isochronous populations of Toxaster granosus kiliani (424 specimens in total) dated from the Verrucosum biozone, and distributed along a proximo-distal gradient. The temporal approach concerns a reference section (Carajuan) ranging from the Lower Valanginian to the Upper Hauterivian, and involving the species T. granosus kiliani and T. gibbus. Sedimentary environments have been characterized by a factorial analysis of five characteristics of facies. Sea urchin morphology has been described with seven measures allowing the computation of two angles (α and β), and of six shape indices analyzed through a principal components analyses. The spatial approach shows that the adult mean size (> 20 mm) increases distally, and that morphology changes significantly across localities. However, only variations in α and β are sequentially organized along the proximo-distal gradient (they correspond to a forward migration of the peristome and to an expansion of the plastronal area). The stratigraphic survey of facies variation along the 369 beds analyzed in Carajuan shows a clear change in sedimentary conditions: from unstable with bioclastic events (Valanginian), to homogeneous with a low content in bioclasts (Hauterivian). Most Toxaster specimens are concentrated in three stratigraphic units (Campylotoxus and Verrucosum biozones for T. granosus kiliani; Sayni biozone for T. gibbus), their abundance being related to the macrofaunal presence and diversity and to burrowing activity. The adult mean size is only significantly related to facies variation, for the T. granosus kiliani from the Verrucosum biozone, increasing with textural gradient and bioclastic content. Shape - facies relationships have been identified for T. granosus kiliani in both Campylotoxus and Verrucosum intervals. However, the morphological variables and facies characteristics involved differ between the two biozones. The synthesis of all significant relationships between size or shape and facies characteristics demonstrates that the response of Toxaster to environmental changes was limited, and varied in space as well as for the different periods of time considered. The only recurring impact of sedimentary changes involved sea urchin abundance, that is, their ability to settle. The low adaptive potential of Toxaster is discussed in the context of the early radiation of the Spatangoida.     

Le « Mégalosaure » (Dinosauria,Sauropoda) de Saint-Agnant (Charente-Maritime,France) : description et origine stratigraphique

The “Megalosaur” remains from Saint-Agnant (Charente-Maritime, France), reported as early as 1881 by Boissellier, are here described and figured for the first time. These bones, as well as a few additional specimens from the nearby locality of Soubise, belong in fact to an indeterminate sauropod. The stratigraphical position of these remains unambiguously indicates an infra-Cenomanian age. However, the presence in this area of continental deposits with Purbeckian and Wealden facies does not allow to decide between an earliest or late Early Cretaceous age.     

A jumping translocation (5p;15q), (8q;15q), and (12q;15q) (author's transl)]

Three balanced karyotypes (5p;15q), (8q;15q), and (12q;15q) were found simultaneously in a child with the Willi-Prader syndrome. The hypothesis is presented of a "jumping# translocation by affinity of telomeric and interstitial palindromes. The relationship between the Willi-Prader syndrome and a juxtacentric anomaly of the long arm of chromosome 15 is discussed.     

Synthesis of beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp-(1-->3)-beta-D-Glcp-(1-->6)-[beta-D-Galp-(1-->4)-beta-D-Glcp-(1-->3)]-beta-D-GlcpOLauryl, an oligosaccharide with anti-tumor activity

A concise and effective synthesis of lauryl heptasaccharide 17 was achieved from the key intermediates lauryl 2,3,4,6-tetra-O-benzoyl-beta-D-galactopyranosyl-(1-->4)-2,3,6-tri-O-benzoyl-beta-D-glucopyranosyl-(1-->3)-2,4-di-O-benzoyl-beta-D-glucopyranoside (10) and isopropyl 2,4,6-tri-O-acetyl-3-O-allyl-beta-D-glucopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-2,4-di-O-acetyl-beta-D-glucopyranosyl-(1-->3)-2,4,6-tri-O-acetyl-1-thio-beta-D-glucopyranoside (15). The key trisaccharide glycosyl acceptor 10 was constructed by coupling 2,3,4,6-tetra-O-benzoyl-beta-D-galactopyranosyl-(1-->4)-2,3,6-tri-O-benzoyl-alpha-D-glucopyranosyl trichloroacetimidate (3) with lauryl 6-O-acetyl-2,4-di-O-benzoyl-beta-D-glucopyranoside (9), followed by deacetylation. The thioglycoside donor 15 was obtained by condensation of 2,4,6-tri-O-acetyl-3-O-allyl-beta-D-glucopyranosyl-(1-->3)-[2,3,4,6-tetra-O-benzoyl-beta-D-glucopyranosyl-(1-->6)]-2,4-di-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate (11) with isopropyl 4,6-O-benzylidene-1-thio-beta-D-glucopyranoside (12), followed by debenzylidenation and acetylation. A bioassay of the inhibition of S180 noumenal tumors showed that lauryl heptasaccharide 17 could be employed as a potential agent for cancer treatment.     

Synthesis of divalent beta-(1-->6)-branched (1-->3)-glucohexaose and trivalent beta-(1-->6)-branched (1-->3)-glucotriose

Hexaose, beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp, based dimers were synthesized by twofold glycosidation of the hexaosyl trichloroacetimidate with hexylene 1,6-diol, diethylene glycol and triethylene glycol, respectively. Meanwhile, a triose, beta-1D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp, based trimer was obtained by glycosidation of the triosyl trichloroacetimidate with a glycerol-derived triol scaffold.     

On diapause in <Emphasis Type="Italic">Leis dimidiata</Emphasis> (Fabr.) (Coleoptera,Coccinellidae)

The experiments have shown that at least the Guangzhou populations of Leis dimidiata (Coleoptera, Coccinellidae) have no photoperiodic diapause.     

<Emphasis Type="Italic">Siderocelis irregularis</Emphasis> (Chlorophyta,Trebouxiophyceae) in Lake Tanganyika (Africa)

Siderocelis irregularis Hindák, representing a genus Siderocelis (Naumann) Fott that is known from European temperate waters, was identified as a common phytoplankter in Lake Tanganyika. It was found aposymbiotic as well as ingested (possibly endosymbiotic) in lake heterotrophs, mainly Strombidium sp. and Vorticella spp. The morphology and ultrastructure of the species, studied with LM, SEM and TEM, are described with emphasis on the structure of the cell wall and the pyrenoid. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.     

Groupe de Candona clivosa, nouveau groupe de Candoninae (Crustacea, Ostracoda) et sa diversification dans le Bassin de Turiec (Slovaquie) au Miocène supérieur

The Candona clivosa-group, a new group of Candoninae - is erected on the base of the folded inner lamella observed on the postero-ventral border of the female valve. The elongated sub-triangular and rectangular valves of this group are described from the Miocene and Quaternary deposits of Europe. A folded inner lamella is also observed in 11 species of Candona from the Upper Miocene of the Turiec Basin of which 8 are new - Candona fatrica nov. sp., C. tatrica nov. sp., C. lacustris nov. sp., C. palustris nov. sp., C. stagnosa nov. sp., C. laterisimilis nov. sp., C. jiriceki nov. sp. and C. incurva nov. sp. They show a higher variability of the outline, calcification of the valves and width of the zone of concrescence. The extrinsic and intrinsic aspects of this morphological diversification in the Turiec Basin are discussed.