Palmitate increases Nur77 expression by modulating ZBP89 and Sp1 binding to the Nur77 proximal promoter in pancreatic β-cells

Nur77 is a stress sensor in pancreatic β-cells, which negatively regulates glucose-stimulated insulin secretion. We recently showed that a lipotoxic shock caused by exposure of β-cells to the saturated fatty acid palmitate strongly increases Nur77 expression. Here, using dual luciferase reporter assays and Nur77 promoter deletion constructs, we identified a regulatory cassette between −1534 and −1512 bp upstream from the translational start site mediating Nur77 promoter activation in response to palmitate exposure. Chromatin immunoprecipitation, transient transfection and siRNA-mediated knockdown assays revealed that palmitate induced Nur77 promoter activation involves Sp1 recruitment and ZBP89 release from the gene promoter.     

Effect of symbiont acquisition on growth,survival and fertility of the terrestrial isopod Porcellionides pruinosus (Crustacea,Oniscidea)

Growth rate, survival, mean size of reproductive females and fertility were assessed in the terrestrial isopod Porcellionides pruinosus fed an artificial diet supplemented with potential sources of symbionts. The acquisition of symbionts was experimentally manipulated through feeding experiments to investigate the effect of the acquisition mechanism on isopod performances over 4 months. Five groups of isolated newborn were fed differently (basal diet or control; basal diet with leaf litter, faeces, gut; and basal diet mixed with antibiotic), weighed and counted at 0, 2 and 4 months. Growth rate differed significantly between diet groups at 2 and 4 months. No significant difference of survival was detected, but groups fed on a diet with supplements (leaf litter, faeces and gut) had a higher rate of survival. Size and fertility of reproductive females differed significantly across diet groups. Our findings showed the importance of the acquisition mode of symbionts on the life history of Oniscidea and the role of diet intake on the performance of P. pruinosus.     

Variation in volatiles of Astragalus gombiformis Pomel

The essential oils obtained by hydrodistillation (Clevenger apparatus) from aerial parts of Astragalus gombiformis were analysed by gas chromatography coupled with mass spectrometry (GC/MS). This study showed that the A. gombiformis essential oils are complex mixtures of important natural compounds, which varied qualitatively and quantitatively between cultivated and wild plants and between phenological stages of development. All analysed oils are characterized by the constant presence of phytol, 6,10,14-trimethyl-2-pentadecanone, 4-terpineol, and gamma-terpinene. This study is the first report on the chemical composition of essential oils from A. gombiformis and indicates that these oils should be more studied.     

Composition of a molluscan assemblage associated with macrophytes in Menzel Jemil (Bizerte lagoon,SW Mediterranean Sea)

The molluscan species composition and diversity associated with macrophytes was studied throughout 1 year at Menzel Jemil station (Bizerte lagoon, north‐west of Tunisia). A total of 7,539 individuals belonging to 13 species were collected. The molluscan assemblage was mainly composed of gastropods (98.12%, nine species), followed by bivalves (1.88%, four species). Hydrobia acuta ranked first with 49.97% of total abundance, followed by Bittium reticulatum (17.97%), Tritia mutabilis (11.38%), Haminoea navicula (8.98%), Phorcus articulatus (5.17%) and Cerithium vulgatum (3.94%). The large number of juvenile molluscs collected confirms the importance of macroalgae and seagrass for mollusc recruitment. Significant temporal variations of species richness, density and diversity indices of the mollusc assemblage have been observed during the year. Multivariate analyses applied to our data revealed significant relationships between the macrophyte composition and associated molluscan assemblage. The BIOENV analysis indicated that water temperature, phosphates concentration and macrophyte biomass were environmental variables most closely associated with the temporal variation of molluscan assemblage.     

Contrasted TCRβ Diversity of CD8+ and CD8? T Cells in Rainbow Trout

Teleost fish express highly diverse naive TCRβ (TRB) repertoires and mount strong public and private clonal responses upon infection with pathogens. Fish T cells express typical markers such as CD8, CD4-1 and CD4-2, CD3, CD28 and CTLA4. Fish CD8⁺ T cells have been shown to be responsible for antigen-specific cell-mediated cytotoxicity in in vitro systems using histo-compatible effector and target cells. We compare here the complexity of TRB repertoires between FACS sorted CD8⁺ and CD8⁻ T cells from spleen and pronephros of rainbow trout. In contrast to human, while the TRB repertoire is highly diverse and polyclonal in CD8⁺ T cells of naïve fish, it appeared very different in CD8⁻ lymphocytes with irregular CDR3 length distributions suggesting a dominance of activated clones already in naïve fish or the presence of non conventional T cells. After infection with a systemic virus, CD8⁺ T cells mount a typical response with significant skewing of CDR3 length profiles. The infection also induces significant modifications of the TRB repertoire expressed by the CD8⁻ fraction, but for a different set of V/J combinations. In this fraction, the antiviral response results in an increase of the peak diversity of spectratypes. This unusual observation reflects the presence of a number of T cell expansions that rise the relative importance of minor peaks of the highly skewed distributions observed in unchallenged animals. These results suggest that the diversity of TRB expressed by CD8⁺ and CD8⁻ αβ T cells may be subjected to different regulatory patterns in fish and in mammals.     

Erratum to: C3 Polymorphism Influences Circulating Levels of C3, ASP and Lipids in Schizophrenic Patients

Neurochemical Research -     

A novel RING finger protein,human enhancer of invasion 10, alters mitotic progression through regulation of cyclin B levels

The process of cellular morphogenesis is highly conserved in eukaryotes and is dependent upon the function of proteins that are centrally involved in specification of the cell cycle. The human enhancer of invasion clone 10 (HEI10) protein was identified from a HeLa cell library based on its ability to promote yeast agar invasion and filamentation. Through two-hybrid screening, the mitotic cyclin B1 and an E2 ubiquitin-conjugating enzyme were isolated as HEI10-interacting proteins. Mutation of the HEI10 divergent RING finger motif (characteristic of E3 ubiquitin ligases) and Cdc2/cyclin binding and phosphorylation sites alter HEI10-dependent yeast phenotypes, including delay in G(2)/M transition. In vertebrates, the addition of HEI10 inhibits nuclear envelope breakdown and mitotic entry in Xenopus egg extracts. Mechanistically, HEI10 expression reduces cyclin B levels in cycling Xenopus eggs and reduces levels of the cyclin B ortholog Clb2p in yeast. HEI10 is itself a specific in vitro substrate of purified cyclin B/cdc2, with a TPVR motif as primary phosphorylation site. Finally, HEI10 is itself ubiquitinated in egg extracts and is also autoubiquitinated in vitro. These and other points lead to a model in which HEI10 defines a divergent class of E3 ubiquitin ligase, functioning in progression through G(2)/M.