275 research outputs found

    Left gaze bias in humans, rhesus monkeys and domestic dogs

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    While viewing faces, human adults often demonstrate a natural gaze bias towards the left visual field, that is, the right side of the viewee’s face is often inspected first and for longer periods. Using a preferential looking paradigm, we demonstrate that this bias is neither uniquely human nor limited to primates, and provide evidence to help elucidate its biological function within a broader social cognitive framework. We observed that 6-month-old infants showed a wider tendency for left gaze preference towards objects and faces of different species and orientation, while in adults the bias appears only towards upright human faces. Rhesus monkeys showed a left gaze bias towards upright human and monkey faces, but not towards inverted faces. Domestic dogs, however, only demonstrated a left gaze bias towards human faces, but not towards monkey or dog faces, nor to inanimate object images. Our findings suggest that face- and species-sensitive gaze asymmetry is more widespread in the animal kingdom than previously recognised, is not constrained by attentional or scanning bias, and could be shaped by experience to develop adaptive behavioural significance

    Rhesus Monkeys See Who They Hear: Spontaneous Cross-Modal Memory for Familiar Conspecifics

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    Rhesus monkeys gather much of their knowledge of the social world through visual input and may preferentially represent this knowledge in the visual modality. Recognition of familiar faces is clearly advantageous, and the flexibility and utility of primate social memory would be greatly enhanced if visual memories could be accessed cross-modally either by visual or auditory stimulation. Such cross-modal access to visual memory would facilitate flexible retrieval of the knowledge necessary for adaptive social behavior. We tested whether rhesus monkeys have cross-modal access to visual memory for familiar conspecifics using a delayed matching-to-sample procedure. Monkeys learned visual matching of video clips of familiar individuals to photographs of those individuals, and generalized performance to novel videos. In crossmodal probe trials, coo-calls were played during the memory interval. The calls were either from the monkey just seen in the sample video clip or from a different familiar monkey. Even though the monkeys were trained exclusively in visual matching, the calls influenced choice by causing an increase in the proportion of errors to the picture of the monkey whose voice was heard on incongruent trials. This result demonstrates spontaneous cross-modal recognition. It also shows that viewing videos of familiar monkeys activates naturally formed memories of real monkeys, validating the use of video stimuli in studies of social cognition in monkeys

    Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus

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    Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing—observation, approach and usually harassment of a predator—being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory

    Cryptosporidium Priming Is More Effective than Vaccine for Protection against Cryptosporidiosis in a Murine Protein Malnutrition Model

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    Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming strategies to overcome the PM-induced susceptibility. We determined that while PM fundamentally alters systemic and mucosal primary immune responses to Cryptosporidium, priming with C. parvum (106 oocysts) provides robust protective immunity against re-challenge despite ongoing PM. C. parvum priming restores mucosal Th1-type effectors (CD3+CD8+CD103+ T-cells) and cytokines (IFNγ, and IL12p40) that otherwise decrease with ongoing PM. Vaccination strategies with Cryptosporidium antigens expressed in the S. Typhi vector 908htr, however, do not enhance Th1-type responses to C. parvum challenge during PM, even though vaccination strongly boosts immunity in challenged fully nourished hosts. Remote non-specific exposures to the attenuated S. Typhi vector alone or the TLR9 agonist CpG ODN-1668 can partially attenuate C. parvum severity during PM, but neither as effectively as viable C. parvum priming. We conclude that although PM interferes with basal and vaccine-boosted immune responses to C. parvum, sustained reductions in disease severity are possible through mucosal activators of host defenses, and specifically C. parvum priming can elicit impressively robust Th1-type protective immunity despite ongoing protein malnutrition. These findings add insight into potential correlates of Cryptosporidium immunity and future vaccine strategies in malnourished children

    EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2013 . Scientific opinion on Dietary Reference Values for fluoride

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    Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) derived Dietary Reference Values (DRVs) for fluoride, which are provided as Adequate Intake (AI) from all sources, including non-dietary sources. Fluoride is not an essential nutrient. Therefore, no Average Requirement for the performance of essential physiological functions can be defined. Nevertheless, the Panel considered that the setting of an AI is appropriate because of the beneficial effects of dietary fluoride on prevention of dental caries. The AI is based on epidemiological studies (performed before the 1970s) showing an inverse relationship between the fluoride concentration of water and caries prevalence. As the basis for defining the AI, estimates of mean fluoride intakes of children via diet and drinking water with fluoride concentrations at which the caries preventive effect approached its maximum whilst the risk of dental fluorosis approached its minimum were chosen. Except for one confirmatory longitudinal study in US children, more recent studies were not taken into account as they did not provide information on total dietary fluoride intake, were potentially confounded by the use of fluoride-containing dental hygiene products, and did not permit a conclusion to be drawn on a dose-response relationship between fluoride intake and caries risk. The AI of fluoride from all sources (including non-dietary sources) is 0.05 mg/kg body weight per day for both children and adults, including pregnant and lactating women. For pregnant and lactating women, the AI is based on the body weight before pregnancy and lactation. Reliable and representative data on the total fluoride intake of the European population are not available

    GPR80/99, proposed to be the P2Y15 receptor activated by adenosine and AMP, is not a P2Y receptor

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    The orphan receptor GPR80 (also called GPR99) was recently reported to be the P2Y15 receptor activated by AMP and adenosine and coupled to increases in cyclic AMP accumulation and intracellular Ca2+ mobilization (Inbe et al. J Biol Chem 2004; 279: 19790–9[12]). However, the cell line (HEK293) used to carry out those studies endogenously expresses A2A and A2B adenosine receptors as well as multiple P2Y receptors, which complicates the analysis of a potential P2Y receptor. To determine unambiguously whether GPR80 is a P2Y receptor subtype, HA-tagged GPR80 was either stably expressed in CHO cells or transiently expressed in COS-7 and HEK293 cells, and cell surface expression was verified by radioimmunoassay (RIA). COS-7 cells overexpressing GPR80 showed a consistent twofold increase in basal inositol phosphate accumulation. However, neither adenosine nor AMP was capable of promoting accumulation of either cyclic AMP or inositol phosphates in any of the three GPR80-expressing cells. A recent paper (He et al. Nature 2004; 429: 188–93 [15]) reported that GPR80 is a Gq-coupled receptor activated by the citric acid cycle intermediate, α-ketoglutarate. Consistent with this report, α-ketoglutarate promoted inositol phosphate accumulation in CHO and HEK293 cells expressing GPR80, and pretreatment of GPR80-expressing COS-7 cells with glutamate dehydrogenase, which converts α-ketoglutarate to glutamate, decreased basal levels of inositol phosphates. Taken together, these data demonstrate that GPR80 is not activated by adenosine, AMP or other nucleotides, but instead is activated by α-ketoglutarate. Therefore, GPR80 is not a new member of the P2Y receptor family

    Variation in WNT7A is unlikely to be a cause of familial Congenital Talipes Equinovarus

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    <p>Abstract</p> <p>Background</p> <p>Genetic factors make an important contribution to the aetiology of congenital talipes equinovarus (CTEV), the most common developmental disorder of the lower limb. WNT7A was suggested as a candidate gene for CTEV on the basis of a genome-wide scan for linkage in a large multi-case family. WNT7A is a plausible candidate gene for CTEV as it provides a signal for pattern formation during limb development, and mutation in WNT7A has been reported in a number of limb malformation syndromes.</p> <p>Methods</p> <p>We investigated the role of WNT7A using a family-based linkage approach in our large series of European multi-case CTEV families. Three microsatellite markers were used, of which one (D3S2385) is intragenic, and the other two (D3S2403, D3S1252) are 700 kb 5' to the start and 20 kb from the 3' end of the gene, respectively. Ninety-one CTEV families, comprising 476 individuals of whom 211 were affected, were genotyped. LOD scores using recessive and incomplete-dominant inheritance models, and non-parametric linkage scores, excluded linkage.</p> <p>Results</p> <p>No significant evidence for linkage was observed using either parametric or non-parametric models. LOD scores for the parametric models remained strongly negative in the regions between the markers, and in the 0.5 cM intervals outside the marker map. No significant lod scores were obtained when the data were analysed allowing for heterogeneity.</p> <p>Conclusion</p> <p>Our evidence suggests that the WNT7A gene is unlikely to be a major contributor to the aetiology of familial CTEV.</p
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