140 research outputs found

    Verreaux’s sifaka (Propithecus verreauxi) and ring-tailed lemur (Lemur catta) endoparasitism at the Bezà Mahafaly Special Reserve

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    As hosts, primate behavior is responsible for parasite avoidance and elimination as well as parasite acquisition and transmission among conspecifics. Thus, host behavior is largely responsible for the distribution of parasites in free - ranging populations. We examined the importance of host behavior in acquiring and avoiding parasites that use oral routes by comparing the behavior of sympatric Verreaux’s sifaka (Propithecus verreauxi) and ring - tailed lemurs (Lemur catta) inhabiting the Bezà Mahafaly Special Reserve (BMSR) in Madagascar. For each species, two groups lived in a protected parcel and two groups lived in anthropogenically - disturbed forests. Analysis of 585 fecal samples revealed that the BMSR ring - tailed lemurs harbored six species of nematode worms and three species of protistan parasites. The sifaka harbored only two nematodes. Differences in richness and prevalence appear to be linked to host behavior and the ecological distribution of their parasites. To understand the interplay between behavioral mechanisms to avoid or transmit parasites, we analyzed 683 hours of behavioral observations. BMSR ring - tailed lemurs were observed on the ground significantly more than sifaka and this terrestrial substrate use provides greater opportunities for soil - transmitted parasites to acquire a host. Ring - tailed lemurs using the anthropogenically - disturbed forests harbored parasites not found in the groups inhabiting the protected parcel which they may be acquiring via coprophagy or contact with feces. The arboreality of sifaka allows them to evade most soil-transmitted endoparasites and the patterns of parasitism exhibited by sifaka living in the anthropogenically - disturbed forests did not deviate from the patterns observed among the sifaka living in the protected parcel.RÉSUMÉEn tant qu’hôtes, les lémuriens interviennent dans l’acquisition et la transmission de parasites entre les individus d’une population, mais aussi sur la prévention et l’élimination de ces parasites. Leur comportement est donc largement responsable de la distribution des parasites au sein d’une population non contrôlée. Dans notre étude, nous avons examiné l’importance des facteurs  comportementaux lors de l’acquisition et l’évitement des parasites transmis par voie orale en comparant le comportement des Propithèques de Verreaux (Propithecus verreauxi) et des Makis (Lemur catta) se trouvant dans la Réserve Spéciale du Bezà Mahafaly (RSBM) à Madagascar. Deux groupes de chacune de ces espèces étaient distribués dans une parcelle protégée et deux autres dans des forêts dégradées par l’activité humaine. L’analyse de 585 échantillons fécaux a révélé que les Makis de la RSBM étaient infestés par six espèces de nématodes et trois espèces de parasites protistes tandis que les Propithèques de Verreaux ne l’étaient que par deux espèces de nématodes. Les différences de densité et de fréquence auxquelles étaient trouvés les parasites semblaient être liées au comportement des hôtes et à la distribution écologique de leurs parasites. Pour comprendre la relation entre les mécanismes comportementaux et la transmission des parasites, nous avons analysé le comportement des Propithèques et des Makis lors de 683 heures d’observations. Les Makis de la RSBM ont été observés à terre beaucoup plus souvent que les Propithèques. Cette utilisation du substrat terrestre augmente les possibilités des parasites du sol de trouver un hôte. Les Makis se trouvant dans les forêts perturbées étaient infestés de parasites  absents des excréments des lémuriens distribués dans la parcelle protégée. Il est possible que les parasites aient été transmis par coprophagie ou par contact avec des matières fécales. La tendance des Propithèques à vivre dans les arbres leur permet d’éviter la contagion par la plupart des parasites liés au sol et le comportement des Propithèques distribués dans les forêts perturbées ne diffère guère de celui des Propithèques distribués dans la parcelle protégée

    Chronic inflammatory arthritis drives systemic changes in circadian energy metabolism

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    SignificanceRheumatoid arthritis (RA) is a debilitating chronic inflammatory disease in which symptoms exhibit a strong time-of-day rhythmicity. RA is commonly associated with metabolic disturbance and increased incidence of diabetes and cardiovascular disease, yet the mechanisms underlying this metabolic dysregulation remain unclear. Here, we demonstrate that rhythmic inflammation drives reorganization of metabolic programs in distal liver and muscle tissues. Chronic inflammation leads to mitochondrial dysfunction and dysregulation of fatty acid metabolism, including accumulation of inflammation-associated ceramide species in a time-of-day-dependent manner. These findings reveal multiple points for therapeutic intervention centered on the circadian clock, metabolic dysregulation, and inflammatory signaling

    Lithium Impacts on the Amplitude and Period of the Molecular Circadian Clockwork

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    Lithium salt has been widely used in treatment of Bipolar Disorder, a mental disturbance associated with circadian rhythm disruptions. Lithium mildly but consistently lengthens circadian period of behavioural rhythms in multiple organisms. To systematically address the impacts of lithium on circadian pacemaking and the underlying mechanisms, we measured locomotor activity in mice in vivo following chronic lithium treatment, and also tracked clock protein dynamics (PER2::Luciferase) in vitro in lithium-treated tissue slices/cells. Lithium lengthens period of both the locomotor activity rhythms, as well as the molecular oscillations in the suprachiasmatic nucleus, lung tissues and fibroblast cells. In addition, we also identified significantly elevated PER2::LUC expression and oscillation amplitude in both central and peripheral pacemakers. Elevation of PER2::LUC by lithium was not associated with changes in protein stabilities of PER2, but instead with increased transcription of Per2 gene. Although lithium and GSK3 inhibition showed opposing effects on clock period, they acted in a similar fashion to up-regulate PER2 expression and oscillation amplitude. Collectively, our data have identified a novel amplitude-enhancing effect of lithium on the PER2 protein rhythms in the central and peripheral circadian clockwork, which may involve a GSK3-mediated signalling pathway. These findings may advance our understanding of the therapeutic actions of lithium in Bipolar Disorder or other psychiatric diseases that involve circadian rhythm disruptions

    Cross-Reactive T Cells Are Involved in Rapid Clearance of 2009 Pandemic H1N1 Influenza Virus in Nonhuman Primates

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    In mouse models of influenza, T cells can confer broad protection against multiple viral subtypes when antibodies raised against a single subtype fail to do so. However, the role of T cells in protecting humans against influenza remains unclear. Here we employ a translational nonhuman primate model to show that cross-reactive T cell responses play an important role in early clearance of infection with 2009 pandemic H1N1 influenza virus (H1N1pdm). To “prime” cellular immunity, we first infected 5 rhesus macaques with a seasonal human H1N1 isolate. These animals made detectable cellular and antibody responses against the seasonal H1N1 isolate but had no neutralizing antibodies against H1N1pdm. Four months later, we challenged the 5 “primed” animals and 7 naive controls with H1N1pdm. In naive animals, CD8+ T cells with an activated phenotype (Ki-67+ CD38+) appeared in blood and lung 5–7 days post inoculation (p.i.) with H1N1pdm and reached peak magnitude 7–10 days p.i. In contrast, activated T cells were recruited to the lung as early as 2 days p.i. in “primed” animals, and reached peak frequencies in blood and lung 4–7 days p.i. Interferon (IFN)-γ Elispot and intracellular cytokine staining assays showed that the virus-specific response peaked earlier and reached a higher magnitude in “primed” animals than in naive animals. This response involved both CD4+ and CD8+ T cells. Strikingly, “primed” animals cleared H1N1pdm infection significantly earlier from the upper and lower respiratory tract than the naive animals did, and before the appearance of H1N1pdm-specific neutralizing antibodies. Together, our results suggest that cross-reactive T cell responses can mediate early clearance of an antigenically novel influenza virus in primates. Vaccines capable of inducing such cross-reactive T cells may help protect humans against severe disease caused by newly emerging pandemic influenza viruses

    Global report on preterm birth and stillbirth (2 of 7): discovery science

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    <p>Abstract</p> <p>Background</p> <p>Normal and abnormal processes of pregnancy and childbirth are poorly understood. This second article in a global report explains what is known about the etiologies of preterm births and stillbirths and identifies critical gaps in knowledge. Two important concepts emerge: the continuum of pregnancy, beginning at implantation and ending with uterine involution following birth; and the multifactorial etiologies of preterm birth and stillbirth. Improved tools and data will enable discovery scientists to identify causal pathways and cost-effective interventions.</p> <p>Pregnancy and parturition continuum</p> <p>The biological process of pregnancy and childbirth begins with implantation and, after birth, ends with the return of the uterus to its previous state. The majority of pregnancy is characterized by rapid uterine and fetal growth without contractions. Yet most research has addressed only uterine stimulation (labor) that accounts for <0.5% of pregnancy.</p> <p>Etiologies</p> <p>The etiologies of preterm birth and stillbirth differ by gestational age, genetics, and environmental factors. Approximately 30% of all preterm births are indicated for either maternal or fetal complications, such as maternal illness or fetal growth restriction. Commonly recognized pathways leading to preterm birth occur most often during the gestational ages indicated: (1) inflammation caused by infection (22-32 weeks); (2) decidual hemorrhage caused by uteroplacental thrombosis (early or late preterm birth); (3) stress (32-36 weeks); and (4) uterine overdistention, often caused by multiple fetuses (32-36 weeks). Other contributors include cervical insufficiency, smoking, and systemic infections. Many stillbirths have similar causes and mechanisms. About two-thirds of late fetal deaths occur during the antepartum period; the other third occur during childbirth. Intrapartum asphyxia is a leading cause of stillbirths in low- and middle-income countries.</p> <p>Recommendations</p> <p>Utilizing new systems biology tools, opportunities now exist for researchers to investigate various pathways important to normal and abnormal pregnancies. Improved access to quality data and biological specimens are critical to advancing discovery science. Phenotypes, standardized definitions, and uniform criteria for assessing preterm birth and stillbirth outcomes are other immediate research needs.</p> <p>Conclusion</p> <p>Preterm birth and stillbirth have multifactorial etiologies. More resources must be directed toward accelerating our understanding of these complex processes, and identifying upstream and cost-effective solutions that will improve these pregnancy outcomes.</p

    The Steady State Great Ape? Long Term Isotopic Records Reveal the Effects of Season, Social Rank and Reproductive Status on Bonobo Feeding Behavior

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    Dietary ecology of extant great apes is known to respond to environmental conditions such as climate and food availability, but also to vary depending on social status and life history characteristics. Bonobos (Pan paniscus) live under comparatively steady ecological conditions in the evergreen rainforests of the Congo Basin. Bonobos are an ideal species for investigating influences of sociodemographic and physiological factors, such as female reproductive status, on diet. We investigate the long term dietary pattern in wild but fully habituated bonobos by stable isotope analysis in hair and integrating a variety of long-term sociodemographic information obtained through observations. We analyzed carbon and nitrogen stable isotopes in 432 hair sections obtained from 101 non-invasively collected hair samples. These samples represented the dietary behavior of 23 adult bonobos from 2008 through 2010. By including isotope and crude protein data from plants we could establish an isotope baseline and interpret the results of several general linear mixed models using the predictors climate, sex, social rank, reproductive state of females, adult age and age of infants. We found that low canopy foliage is a useful isotopic tracer for tropical rainforest settings, and consumption of terrestrial herbs best explains the temporal isotope patterns we found in carbon isotope values of bonobo hair. Only the diet of male bonobos was affected by social rank, with lower nitrogen isotope values in low-ranking young males. Female isotope values mainly differed between different stages of reproduction (cycling, pregnancy, lactation). These isotopic differences appear to be related to changes in dietary preference during pregnancy (high protein diet) and lactation (high energy diet), which allow to compensate for different nutritional needs during maternal investment

    Gravitational Wave Detection by Interferometry (Ground and Space)

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    Significant progress has been made in recent years on the development of gravitational wave detectors. Sources such as coalescing compact binary systems, neutron stars in low-mass X-ray binaries, stellar collapses and pulsars are all possible candidates for detection. The most promising design of gravitational wave detector uses test masses a long distance apart and freely suspended as pendulums on Earth or in drag-free craft in space. The main theme of this review is a discussion of the mechanical and optical principles used in the various long baseline systems in operation around the world - LIGO (USA), Virgo (Italy/France), TAMA300 and LCGT (Japan), and GEO600 (Germany/U.K.) - and in LISA, a proposed space-borne interferometer. A review of recent science runs from the current generation of ground-based detectors will be discussed, in addition to highlighting the astrophysical results gained thus far. Looking to the future, the major upgrades to LIGO (Advanced LIGO), Virgo (Advanced Virgo), LCGT and GEO600 (GEO-HF) will be completed over the coming years, which will create a network of detectors with significantly improved sensitivity required to detect gravitational waves. Beyond this, the concept and design of possible future "third generation" gravitational wave detectors, such as the Einstein Telescope (ET), will be discussed.Comment: Published in Living Reviews in Relativit
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