Behavioral and neural correlates of communication via pointing

Communicative pointing is a human specific gesture which allows sharing information about a visual item with another person. It sets up a three-way relationship between a subject who points, an addressee and an object. Yet psychophysical and neuroimaging studies have focused on non-communicative pointing, which implies a two-way relationship between a subject and an object without the involvement of an addressee, and makes such gesture comparable to touching or grasping. Thus, experimental data on the communicating function of pointing remain scarce. Here, we examine whether the communicative value of pointing modifies both its behavioral and neural correlates by comparing pointing with or without communication. We found that when healthy participants pointed repeatedly at the same object, the communicative interaction with an addressee induced a spatial reshaping of both the pointing trajectories and the endpoint variability. Our finding supports the hypothesis that a change in reference frame occurs when pointing conveys a communicative intention. In addition, measurement of regional cerebral blood flow using H(2)O(15) PET-scan showed that pointing when communicating with an addressee activated the right posterior superior temporal sulcus and the right medial prefrontal cortex, in contrast to pointing without communication. Such a right hemisphere network suggests that the communicative value of pointing is related to processes involved in taking another person's perspective. This study brings to light the need for future studies on communicative pointing and its neural correlates by unraveling the three-way relationship between subject, object and an addressee.     

Diversity of Culturable Bacteria,from the Anaerobic Zone of the Meromictic Lake Pavin,Able to Perform Dissimilatory-Iron Reduction in Different in Vitro Conditions

A culture-dependent study was performed with the aim of assessing the carbon, electron and Fe(III) sources used for the dissimilatory Fe(III) reduction pathway and the diversity of culturable Fe(III)-reducers in the anoxic zone of the meromictic Lake Pavin. This metabolic pathway was investigated in enrichment cultures inoculated with water samples collected at 70 m depth in the anoxic zone of Lake Pavin. Combinations of different media, organic acids, and incubation gas phases were performed. The potential for Fe(III) reduction in the different growth conditions was assessed by measuring the accumulation of Fe(II) overtime. Bacterial community structure was determined in each growth conditions by Temporal Temperature gradient Gel Electrophoresis (TTGE) profiles of 16S rDNA genes and bands of interest in positive enrichments were sequenced. Comparisons of bacterial community structure between growth conditions revealed that the electron donor, the basal media as well as the Fe(III) source yielded to the selection of different bacterial populations, suggesting that Fe(III) reducers occupy different ecological niches in the anoxic zone of Lake Pavin. Facultative Fe(III) reducers, such as fermentative (e.g., Pseudomonas, Clostridium) and sulphate-reducing (e.g., Desulfovibrio sp.) bacteria, were retrieved in enrichments but well-known obligatory Fe(III) reducers (e.g., Geobacter) were not detected. A greater Fe(III) reduction was noted under H₂:CO₂ gas phase, suggesting that H₂ is used as an electron donor for Fe(III) reduction. Acetate was not used as a precursor for this terminal electron-accepting process, and a high Fe(III) reduction was observed with fumarate provided as the electron donor and carbon sources suggesting that this metabolite may be energetically more beneficial for Fe(III)-reducers.     

Phylogenetic Diversity of Archaea and Bacteria in the Anoxic Zone of a Meromictic Lake (Lake Pavin, France)

The compositions of archaeal and bacterial populations at different depths (60 m [mixolimnion-chemocline interface], 70 m [chemocline-subchemocline interface], 90 m, and 92 m [the water-sediment interface]) in the anoxic zone of the water column in Lake Pavin, a freshwater permanently stratified mountain lake in France, were determined. Phylogenetic trees were constructed from sequences to assess archaeal and bacterial diversity at the four sites.     

GDF15 Provides an Endocrine Signal of Nutritional Stress in Mice and Humans

1. Download high-res image (208KB)
2. Download full-size image

     

Der p 1 is the primary activator of Der p 3, Der p 6 and Der p 9 the proteolytic allergens produced by the house dust mite Dermatophagoides pteronyssinus

Background

The enzymatic activity of the four proteases found in the house dust mite Dermatophagoides pteronyssinus is involved in the pathogenesis of allergy. Our aim was to elucidate the activation cascade of their corresponding precursor forms and particularly to highlight the interconnection between proteases during this cascade.

Methods

The cleavage of the four peptides corresponding to the mite zymogen activation sites was studied on the basis of the Förster Resonance Energy Transfer method. The proDer p 6 zymogen was then produced in Pichia pastoris to elucidate its activation mechanism by mite proteases, especially Der p 1. The role of the propeptide in the inhibition of the enzymatic activity of Der p 6 was also examined. Finally, the Der p 1 and Der p 6 proteases were localised via immunolocalisation in D. pteronyssinus.

Results

All peptides were specifically cleaved by Der p 1, such as proDer p 6. The propeptide of proDer p 6 inhibited the proteolytic activity of Der p 6, but once cleaved, it was degraded by the protease. The Der p 1 and Der p 6 proteases were both localised to the midgut of the mite.

Conclusions

Der p 1 in either its recombinant form or in the natural context of house dust mite extracts specifically cleaves all zymogens, thus establishing its role as a major activator of both mite cysteine and serine proteases.

General significance

This finding suggests that Der p 1 may be valuable target against mites.     

Emotional Reactions of Mothers Facing Premature Births: Study of 100 Mother-Infant Dyads 32 Gestational Weeks

Objectives

This current study has been conducted to clarify the relationship between the mother''s post-traumatic reaction triggered by premature birth and the mother-infant interactions. In this article, the precocious maternal feelings are described.

Methods

A multicenter prospective study was performed in three French hospitals. 100 dyads with 100 very premature infants and their mothers were recruited. Mothers completed, at two different times self-questionnaires of depression/anxiety, trauma and social support. The quality of interactions in the dyads was evaluated.

Results

Thirty-nine percent of the mothers obtained a score at HADS suggesting a high risk of depression at the first visit and approximately one-third at visit two. Seventy-five percent of the mothers were at risk of suffering from an anxiety disorder at visit one and half remained so at visit two. A “depressed” score at visits one and two correlated with a hospitalization for a threatened premature labor. We noted a high risk of trauma for 35% of the mothers and high interactional synchrony was observed for approximately two-thirds of the dyads. The mothers'' psychological reactions such as depression and anxiety or postnatal depression correlate strongly with the presence of an initial trauma. At visit one and visit two, a high score of satisfaction concerning social support correlates negatively with presence of a trauma. A maternal risk of trauma is more frequent with a C-section delivery.

Conclusions

Mothers'' psychological reactions such as depression and anxiety correlate greatly with the presence of an initial trauma. The maternal traumatic reaction linked to premature birth does not correlate with the term at birth, but rather with the weight of the baby. Social support perceived by the mother is correlated with the absence of maternal trauma before returning home, and also seems to inhibit from depressive symptoms from the time of the infant''s premature birth.     

Generation of protein isoform diversity by alternative initiation of translation at non-AUG codons

The use of several translation initiation codons in a single mRNA, by expressing several proteins from a single gene, contributes to the generation of protein diversity. A small, yet growing, number of mammalian mRNAs initiate translation from a non-AUG codon, in addition to initiating at a downstream in-frame AUG codon. Translation initiation on such mRNAs results in the synthesis of proteins harbouring different amino terminal domains potentially conferring on these isoforms distinct functions. Use of non-AUG codons appears to be governed by several features, including the sequence context and the secondary structure surrounding the codon. Selection of the downstream initiation codon can occur by leaky scanning of the 43S ribosomal subunit, internal entry of ribosome or ribosomal shunting. The biological significance of non-AUG alternative initiation is demonstrated by the different subcellular localisations and/or distinct biological functions of the isoforms translated from the single mRNA as illustrated by the two main angiogenic factor genes encoding the fibroblast growth factor 2 (FGF2) and the vascular endothelial growth factor (VEGF). Consequently, the regulation of alternative initiation of translation might have a crucial role for the biological function of the gene product.     

Contrasted patterns of molecular evolution in dominant and recessive self-incompatibility haplotypes in Arabidopsis

Self-incompatibility has been considered by geneticists a model system for reproductive biology and balancing selection, but our understanding of the genetic basis and evolution of this molecular lock-and-key system has remained limited by the extreme level of sequence divergence among haplotypes, resulting in a lack of appropriate genomic sequences. In this study, we report and analyze the full sequence of eleven distinct haplotypes of the self-incompatibility locus (S-locus) in two closely related Arabidopsis species, obtained from individual BAC libraries. We use this extensive dataset to highlight sharply contrasted patterns of molecular evolution of each of the two genes controlling self-incompatibility themselves, as well as of the genomic region surrounding them. We find strong collinearity of the flanking regions among haplotypes on each side of the S-locus together with high levels of sequence similarity. In contrast, the S-locus region itself shows spectacularly deep gene genealogies, high variability in size and gene organization, as well as complete absence of sequence similarity in intergenic sequences and striking accumulation of transposable elements. Of particular interest, we demonstrate that dominant and recessive S-haplotypes experience sharply contrasted patterns of molecular evolution. Indeed, dominant haplotypes exhibit larger size and a much higher density of transposable elements, being matched only by that in the centromere. Overall, these properties highlight that the S-locus presents many striking similarities with other regions involved in the determination of mating-types, such as sex chromosomes in animals or in plants, or the mating-type locus in fungi and green algae.     

Glycoproteins are species-specific markers and major IgE reactants in grass pollens

Grass pollen allergic patients are concomitantly exposed and sensitized to pollens from multiple Pooideae (i.e. common grass) species. As such, they are currently desensitized by allergen‐specific immunotherapy using extracts made from mixes of pollens from Anthoxanthum odoratum, Dactylis glomerata, Lolium perenne, Phleum pratense and Poa pratensis. Herein, we demonstrate that species‐specific glycoprotein patterns are documented by 1D and 2D electrophoresis and Western blotting analysis, which can be used as an identity test for such pollens. Most allergens are glycoproteins bearing complex N‐glycans encompassing β1,2 xylose and α1,3 fucose glycoepitopes. Glycoepitope destruction using periodate oxidation has no impact on seric IgE reactivity in 75% atopic patients (n = 24). The latter have thus no significant IgE responses to carbohydrate‐containing epitopes. In contrast, periodate treatment strongly impairs IgE recognition of glycoallergens in 25% of patients tested, demonstrating the presence of carbohydrate‐specific IgE in those patients. While the clinical impact of carbohydrate‐specific IgE is still a matter of controversy, the presence of these IgE in the serum of many allergic patients illustrates the need for cross‐reacting carbohydrate epitope‐free recombinant allergens to develop relevant diagnostic tests. These data also support the pertinence of mixing multiple grass pollens to desensitize atopic patients, with the aim to broaden the repertoire of glycoepitopes in the vaccine, thus mimicking natural exposure conditions.