Cross-modal prediction in speech perception

Speech perception often benefits from vision of the speaker's lip movements when they are available. One potential mechanism underlying this reported gain in perception arising from audio-visual integration is on-line prediction. In this study we address whether the preceding speech context in a single modality can improve audiovisual processing and whether this improvement is based on on-line information-transfer across sensory modalities. In the experiments presented here, during each trial, a speech fragment (context) presented in a single sensory modality (voice or lips) was immediately continued by an audiovisual target fragment. Participants made speeded judgments about whether voice and lips were in agreement in the target fragment. The leading single sensory context and the subsequent audiovisual target fragment could be continuous in either one modality only, both (context in one modality continues into both modalities in the target fragment) or neither modalities (i.e., discontinuous). The results showed quicker audiovisual matching responses when context was continuous with the target within either the visual or auditory channel (Experiment 1). Critically, prior visual context also provided an advantage when it was cross-modally continuous (with the auditory channel in the target), but auditory to visual cross-modal continuity resulted in no advantage (Experiment 2). This suggests that visual speech information can provide an on-line benefit for processing the upcoming auditory input through the use of predictive mechanisms. We hypothesize that this benefit is expressed at an early level of speech analysis.     

Nairovirus RNA sequences expressed by a Semliki Forest virus replicon induce RNA interference in tick cells

We report the successful infection of the cell line ISE6 derived from Ixodes scapularis tick embryos by the tick-borne Hazara virus (HAZV), a nairovirus in the family Bunyaviridae. Using a recombinant Semliki Forest alphavirus replicon that replicates in these cells, we were able to inhibit replication of HAZV, and we showed that this blockage is mediated by the replication of the Semliki Forest alphavirus replicon; the vector containing the HAZV nucleoprotein gene in sense or antisense orientation efficiently inhibited HAZV replication. Moreover, expression of a distantly related nucleoprotein gene from Crimean-Congo hemorrhagic fever nairovirus failed to induce HAZV silencing, indicating that the inhibition is sequence specific. The resistance of these cells to replicate HAZV correlated with the detection of specific RNase activity and 21- to 24-nucleotide-long small interfering RNAs. Altogether, these results strongly suggest that pathogen-derived resistance can be established in the tick cells via a mechanism of RNA interference.     

Internal point mutations of the capsid modify the serotype of Rice yellow mottle virus

Rice yellow mottle virus is classified in five major serotypes; the molecular diversity of the coat protein (CP) is well established, but the amino acids involved in the recognition by discriminant monoclonal antibodies (MAbs) remain unknown. Reconstruction of a phylogenetic tree and sequence alignment of the CP gene of a sample representative of the continental-large diversity were used to identify 10 serospecific amino acids (i.e., conserved in all isolates belonging to the same serotype and distinct in other serotypes). Positions occupied by serospecific residues were localized on the crystal structure of the CP monomer and on modeled capsomers. Structural, molecular, and serological properties of each serotype were analyzed, and subsequently, hypotheses on the potential role of amino acids in discriminating reactions with antibodies were formulated. The residues 114 and 115 (serospecific of Sr1) and 190 (serospecific of Sr2) were localized on the outer surface of the capsid and might be directly involved in the immunoreactivity with MAb D and MAb A, respectively. In contrast, residues 180 (Sr3) and 178 (Sr5) lay within the inner surface of the capsid. To understand the role of these internal positions in the recognition with the antibodies, two substitutions (T180K and G178D) were introduced in the CP of an infectious clone. These mutations modified the antigenicity with MAb G and MAb E discriminating Sr3 and Sr5, respectively, while the reaction with MAb D remained unaffected. This result suggests an indirect effect of these two internal mutations on local immunostructure while the global structure was maintained.     

Sec22 and Memb11 are v-SNAREs of the anterograde endoplasmic reticulum-Golgi pathway in tobacco leaf epidermal cells

Distinct sets of soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors (SNAREs) are distributed to specific intracellular compartments and catalyze membrane fusion events. Although the central role of these proteins in membrane fusion is established in nonplant systems, little is known about their role in the early secretory pathway of plant cells. Analysis of the Arabidopsis (Arabidopsis thaliana) genome reveals 54 genes encoding SNARE proteins, some of which are expected to be key regulators of membrane trafficking between the endoplasmic reticulum (ER) and the Golgi. To gain insights on the role of SNAREs of the early secretory pathway in plant cells, we have cloned the Arabidopsis v-SNAREs Sec22, Memb11, Bet11, and the t-SNARE Sed5, and analyzed their distribution in plant cells in vivo. By means of live cell imaging, we have determined that these SNAREs localize at the Golgi apparatus. In addition, Sec22 was also distributed at the ER. We have then focused on understanding the function of Sec22 and Memb11 in comparison to the other SNAREs. Overexpression of the v-SNAREs Sec22 and Memb11 but not of the other SNAREs induced collapse of Golgi membrane proteins into the ER, and the secretion of a soluble secretory marker was abrogated by all SNAREs. Our studies suggest that Sec22 and Memb11 are involved in anterograde protein trafficking at the ER-Golgi interface.     

A universal primer set for PCR amplification of nuclear histone H4 genes from all animal species

To control the quality of genomic DNA of samples from a wide variety of animals, a heminested PCR assay specifically targeting a nuclear gene has been developed. The histone H4 gene family comprises a small number of genes considered among the most conserved genes in living organisms. Tissue samples from necropsies and from cells belonging to 43 different species were studied, eight samples from invertebrates and 35 samples from vertebrates covering all classes. Ancient DNA samples from three Siberian woolly mammoths (Mammuthus primigenius) dating between 40,000 and 49,000 years before present were also tested for PCR amplification. Performance of HIST2H4 amplification were also compared with those of previously published universal PCRs (28S rRNA, 18S rRNA, and cytochrome b). Overall, 95% of species studied yielded an amplification product, including some old samples from gorilla and chimpanzees. The data indicate that the HIST2H4 amplimers are, thus, suitable for both DNA quality testing as well as species identification in the animal kingdom.     

Combined antimicrobial resistance in Enterococcus faecium isolated from chickens

Nineteen E. faecium strains isolated from chicken caecum samples, collected in slaughterhouses and highly resistant to vancomycin or gentamicin, were coresistant to erythromycin, and/or tetracyclines, and/or streptogramins, and/or avilamycin. Multiple antibiotic resistance was related to the presence in various combinations of aac(6')-aph(2"), erm(B), emtA, mef(A), tet(L), tet(M), and vanA genes.     

Adipose tissue is a regulated source of interleukin-10

White adipose tissue (WAT) is the source of pro- and anti-inflammatory cytokines and we have recently shown that this tissue is a major source of the anti-inflammatory interleukin (IL)-1 receptor antagonist (IL-1Ra). We now aimed at identifying additional adipose-derived cytokines, which might serve as regulators of IL-1Ra. We demonstrate here for the first time that the antiinflammatory cytokine IL-10 is secreted by human WAT explants and that it is up-regulated by LPS and TNF-alpha in vitro, as well as in obesity in humans (2- and 6-fold increase in subcutaneous and visceral WAT, respectively) and rodents (4-fold increase).     

Development of a fluid functionalized lipidic matrix applied to direct in situ polynucleotide detection

This work presents a new approach for direct detection of polyelectrolytes at the air-water interface, based on the investigation of the interfacial properties of an active lipidic matrix especially designed for polynucleotide immobilization. A synthetic lipid with a cationic spermine headgroup, DiOctadecylamidoGlycylSpermine (DOGS), was spread at the interface to form a distortable film able to capture polynucleotides. The control of the organization state of this functionalized monolayer upon compression was achieved by recording surface pressure-area (pi-A) isotherm diagrams, presenting a specific shape with a typical liquid expanded-liquid condensed phase transition on a pure water subphase. In the presence of various dsDNA concentrations in the subphase, the isotherms were markedly modified in a time and concentration-dependent manner. The main modifications, corresponding to a large shift towards higher molecular areas and a clear fading of the phase transition, were corroborated by the fine analysis of the monolayer compressibility profile, thus suggesting a characteristic change in the monolayer fluidity as a function of both time and DNA concentration. Moreover, an ATR-Fourier transform infrared (ATR-FTIR) characterization showed evidences for the adsorption of DNA strands onto the lipidic matrix. The direct observation of the mixed monolayer morphology by Brewster angle microscopy (BAM) strongly suggests that DNA adsorption induces a reorganization of lipids at the interface, as evidenced by the change in the condensed lipidic domains morphology in the presence of DNA in the subphase. The immobilization of various polynucleotidic probes of 4000, 400 and 22 base length, confirmed by fluorescence microscopy, had similar effects on DOGS interfacial properties. Preliminary studies are finally presented to explore the possibility of using this system for the study of hybridization between complementary strands. Hence, this study demonstrates this functionalized matrix behaves as a fluid support where polynucleotide immobilization induces interfacial properties modifications, which could be further exploited through the experimental characterization of Faraday instabilities sensitive to visco-elasticity variations.     

Efficient synthesis of C-terminal modified peptide ketones for chemical ligations

Synthesis of a C-terminal modified peptide with an -amido methylketone was efficiently carried out using a backbone-amide-type linker loading with a monofunctionalized diamine, provided that no base such as piperidine or diisopropylethylamine or a reducing agent such as triisopopylsilane was used for the synthetic pathway. The ketoxime-forming chemoselective ligation between a methylketone and an aminooxy was quantitative in 5 h at pH 2.