Do Pied Flycatchers Use Personal or Social Information for Replacement Clutch Decisions? A Field Experiment

Life is a continuous stream of decisions: organisms are repeatedly confronted with multiple options from which to choose. To make the best decisions and maximise their fitness, individuals need to collect information: from direct interactions with the environment (personal information) or from observing other individuals interacting with the environment (social information). Yet, very little is known about the details of decision‐making by animals in their natural environments, including the sources of information they use in the process. We set out to determine the relative importance of social and personal information in breeding habitat decisions in the migratory pied flycatcher, Ficedula hypoleuca. In a field experiment in Finland, we manipulated flycatcher breeding success and then allowed individuals to choose among breeding sites labelled with artificial cues (arbitrary symbols) associated with their own (manipulated) and neighbour's reproductive success, respectively, for laying a replacement clutch. Birds did not appear to distinguish among the symbols representing their own, their neighbour's or a neutral symbol, indicating that they did not use either information source when deciding about a replacement clutch. Also, the choice did not influence subsequent investment into breeding (clutch size). This may suggest that pied flycatchers utilise other cues (e.g. breeding success or predation risk on larger scales) when having to make a decision about replacement clutches. We discuss our results in light of constraints imposed by a short breeding season of migratory birds.     

T Cell-Derived IL-10 Determines Leishmaniasis Disease Outcome and Is Suppressed by a Dendritic Cell Based Vaccine

In the murine model of Leishmania major infection, resistance or susceptibility to the parasite has been associated with the development of a Th1 or Th2 type of immune response. Recently, however, the immunosuppressive effects of IL-10 have been ascribed a crucial role in the development of the different clinical correlates of Leishmania infection in humans. Since T cells and professional APC are important cellular sources of IL-10, we compared leishmaniasis disease progression in T cell-specific, macrophage/neutrophil-specific and complete IL-10-deficient C57BL/6 as well as T cell-specific and complete IL-10-deficient BALB/c mice. As early as two weeks after infection of these mice with L. major, T cell-specific and complete IL-10-deficient animals showed significantly increased lesion development accompanied by a markedly elevated secretion of IFN-γ or IFN-γ and IL-4 in the lymph nodes draining the lesions of the C57BL/6 or BALB/c mutants, respectively. In contrast, macrophage/neutrophil-specific IL-10-deficient C57BL/6 mice did not show any altered phenotype. During the further course of disease, the T cell-specific as well as the complete IL-10-deficient BALB/c mice were able to control the infection. Furthermore, a dendritic cell-based vaccination against leishmaniasis efficiently suppresses the early secretion of IL-10, thus contributing to the control of parasite spread. Taken together, IL-10 secretion by T cells has an influence on immune activation early after infection and is sufficient to render BALB/c mice susceptible to an uncontrolled Leishmania major infection.     

Environmental effects on the covariation among pace‐of‐life traits

Pace‐of‐life syndromes (POLSs) are suites of life‐history, physiological and behavioural traits that arise due to trade‐offs between allocation to current and future reproduction. Traits generally show covariation that can arise from genetic and environmental influences on phenotypes and constrain the independent evolution of traits, resulting in fitness consequences and impacts on population dynamics. The notion that correlations among traits may vary among populations along environmental gradients suggests an important role for the environment in shaping and maintaining POLSs. However, no synthesis has been attempted of the myriad ways in which environmental factors should influence POLSs. Here, we formulate a series of hypotheses targeting the critical interfaces of the environment and life‐history ‐ behaviour associations across different organisms. We discuss the hypotheses in light of findings from a systematic review of studies that measured changes in the association between behaviour and life‐history traits as a function of environmental conditions. The review revealed that POLSs are often shaped by environmental variation, where harshness of the environment in early life has the most consistent effects on POLS. However, only partial or no effects of environmental variation were found in a number of studies, which may result from the highly variable study systems, traits and environments studied. We highlight promising directions arising from the available studies and identify knowledge gaps that, if unaddressed, will impede progress in the field.     

Validation of a fully automated COMET assay: 1.75 million single cells measured over a 5 year period

The COMET assay is recognized as a rapid and sensitive method in quantifying radiation induced DNA damage. We investigated the distorting influence of endogenous, assay-inherent factors onto base (single cell level) and primary outcome measures (experimental/slide level), such as olive tail moment (OTM) and percentage DNA in the tail (%tail-DNA). From 2003 to 2008, we performed the assay on lymphocytes isolated from the blood samples of 355 lung cancer patients, 170 controls, and 610 relatives, as well as one single reference individual, repeated 170 times. In total, the data from 10,016 single experiments containing around 1,750,000 cells have been included in this study. This is the first time that the endogenous variability of the COMET assay has been validated systematically on such a huge data set over a 5 year period. Assuming that the reference sample reflects assay specific white noise, we estimated a proportion of 7-95% of the variability of the outcome measures due to assay variation (white noise) depending on parameter, exposure level, and study group. The proportion of white noise was largest for the initial radiation damage. The specific endogenous factors considered attribute to 14.8% of the total variability in the primary outcome measurements of the OTM and 6.9% of the %tail-DNA. OTM turns out to be a sensitive parameter to detect variation, but is also more susceptible to disturbance caused by endogenous factors than %tail-DNA. To reduce the experimental variability in COMET assays, we recommend a highly standardized operation protocol as well as inspecting and/or adjusting the primary outcome measures according to endogenous factors before calculating secondary outcome measures, e.g. DNA repair capacity (DRC) or testing statistical inference. A human reference (HR) sample is also useful to inspect homogeneity in the temporal progression of long lasting investigations, but not for calibrating primary outcome measurements.     

Applying label-free dynamic mass redistribution technology to frame signaling of G protein-coupled receptors noninvasively in living cells

Label-free dynamic mass redistribution (DMR) is a cutting-edge assay technology that enables real-time detection of integrated cellular responses in living cells. It relies on detection of refractive index alterations on biosensor-coated microplates that originate from stimulus-induced changes in the total biomass proximal to the sensor surface. Here we describe a detailed protocol to apply DMR technology to frame functional behavior of G protein-coupled receptors that are traditionally examined with end point assays on the basis of detection of individual second messengers, such as cAMP, Ca(2+) or inositol phosphates. The method can be readily adapted across diverse cellular backgrounds (adherent or suspension), including primary human cells. Real-time recordings can be performed in 384-well microtiter plates and be completed in 2 h, or they can be extended to several hours depending on the biological question to be addressed. The entire procedure, including cell harvesting and DMR detection, takes 1-2 d.     

Additive antinociceptive effects of a combination of vitamin C and vitamin E after peripheral nerve injury

Accumulating evidence indicates that increased generation of reactive oxygen species (ROS) contributes to the development of exaggerated pain hypersensitivity during persistent pain. In the present study, we investigated the antinociceptive efficacy of the antioxidants vitamin C and vitamin E in mouse models of inflammatory and neuropathic pain. We show that systemic administration of a combination of vitamins C and E inhibited the early behavioral responses to formalin injection and the neuropathic pain behavior after peripheral nerve injury, but not the inflammatory pain behavior induced by Complete Freund's Adjuvant. In contrast, vitamin C or vitamin E given alone failed to affect the nociceptive behavior in all tested models. The attenuated neuropathic pain behavior induced by the vitamin C and E combination was paralleled by a reduced p38 phosphorylation in the spinal cord and in dorsal root ganglia, and was also observed after intrathecal injection of the vitamins. Moreover, the vitamin C and E combination ameliorated the allodynia induced by an intrathecally delivered ROS donor. Our results suggest that administration of vitamins C and E in combination may exert synergistic antinociceptive effects, and further indicate that ROS essentially contribute to nociceptive processing in special pain states.     

Effect of constitution on mass of individual organs and their association with metabolic rate in humans--a detailed view on allometric scaling

Resting energy expenditure (REE)-power relationships result from multiple underlying factors including weight and height. In addition, detailed body composition, including fat free mass (FFM) and its components, skeletal muscle mass and internal organs with high metabolic rates (i.e. brain, heart, liver, kidneys), are major determinants of REE. Since the mass of individual organs scales to height as well as to weight (and, thus, to constitution), the variance in these associations may also add to the variance in REE. Here we address body composition (measured by magnetic resonance imaging) and REE (assessed by indirect calorimetry) in a group of 330 healthy volunteers differing with respect to age (17-78 years), sex (61% female) and BMI (15.9-47.8 kg/m(2)). Using three dimensional data interpolation we found that the inter-individual variance related to scaling of organ mass to height and weight and, thus, the constitution-related variances in either FFM (model 1) or kidneys, muscle, brain and liver (model 2) explained up to 43% of the inter-individual variance in REE. These data are the first evidence that constitution adds to the complexity of REE. Since organs scale differently as weight as well as height the "fit" of organ masses within constitution should be considered as a further trait.     

Serum levels of the adipokine chemerin are increased in preeclampsia during and 6 months after pregnancy

Preeclampsia is a serious cardiovascular complication in pregnancy which is associated with an increased future metabolic and cardiovascular risk for mother and newborn. Recently, chemerin was introduced as a novel adipokine inducing insulin resistance in vitro and in vivo. In the current study, we investigated serum concentrations of chemerin by ELISA in control and preeclampsia patients during pregnancy (Control: n=37, preeclampsia: n=37) and 6 months after delivery (Control: n=35, preeclampsia: n=36). Furthermore, the association between chemerin and markers of renal function, glucose and lipid metabolism, as well as inflammation was studied in pregnant patients. Median maternal chemerin concentrations were significantly elevated in preeclampsia patients (249.5 [range: 123.1-366.9] μg/l) as compared to controls (204.8 [138.5-280.8] μg/l) (p<0.001). Furthermore, chemerin serum levels positively correlated with blood pressure, creatinine, free fatty acids, cholesterol, triglycerides (TG), leptin, adiponectin, and C-reactive protein in univariate analyses. In multivariate analyses, TG and leptin remained independently associated with circulating chemerin. Interestingly, median chemerin concentrations 6 months after delivery remained significantly higher in former preeclampsia patients (196.0 [119.8-368.7] μg/l) as compared to controls (152.2 [102.8-216.4] μg/l). Taken together, maternal chemerin serum concentrations are significantly increased in preeclampsia during and after pregnancy. Furthermore, TG and leptin are independent predictors of circulating chemerin during pregnancy.