Hidden crown jewels: the role of tree crowns for bryophyte and lichen species richness in sycamore maple wooded pastures

Tree crowns typically cover the vast majority of the surface area of trees, but they are rarely considered in diversity surveys of epiphytic bryophytes and lichens, especially in temperate Europe. Usually only stems are sampled. We assessed the number of bryophyte and lichen species on stems and in crowns of 80 solitary sycamore maple trees (Acer pseudoplatanus) at six sites in wooded pastures in the northern Alps. The total number of species detected per tree ranged from 13 to 60 for bryophytes, from 25 to 67 for lichens, and from 42 to 104 for bryophytes and lichens considered together. At the tree level, 29 % of bryophyte and 61 % of lichen species were recorded only in the crown. Considering all sampled trees together, only 4 % of bryophyte, compared to 34 % of lichen species, were never recorded on the stem. Five out of 10 red-listed bryophyte species and 29 out of 39 red-listed lichen species were more frequent in crowns. The species richness detected per tree was unexpectedly high, whereas the proportion of exclusive crown species was similar to studies from forest trees. For bryophytes, in contrast to lichens, sampling several stems can give a good estimation of the species present at a site. However, frequency estimates may be highly biased for lichens and bryophytes if crowns are not considered. Our study demonstrates that tree crowns need to be considered in research on these taxa, especially in biodiversity surveys and in conservation tasks involving lichens and to a lesser degree also bryophytes.     

Diaphorina citri populations carrying the bacterial plant pathogen Candidatus Liberibacter asiaticus are more susceptible to infection by entomopathogenic fungi than bacteria‐free populations

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Targeting Survivin Enhances Chemosensitivity in Retinoblastoma Cells and Orthotopic Tumors

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Expectation versus Reality: The Impact of Utility on Emotional Outcomes after Returning Individualized Genetic Research Results in Pediatric Rare Disease Research,a Qualitative Interview Study

PurposeMuch information on parental perspectives on the return of individual research results (IRR) in pediatric genomic research is based on hypothetical rather than actual IRR. Our aim was to understand how the expected utility to parents who received IRR on their child from a genetic research study compared to the actual utility of the IRR received.MethodsWe conducted individual telephone interviews with parents who received IRR on their child through participation in the Manton Center for Orphan Disease Research Gene Discovery Core (GDC) at Boston Children’s Hospital (BCH).ResultsFive themes emerged around the utility that parents expected and actually received from IRR: predictability, management, family planning, finding answers, and helping science and/or families. Parents expressing negative or mixed emotions after IRR return were those who did not receive the utility they expected from the IRR. Conversely, parents who expressed positive emotions were those who received as much or greater utility than expected.ConclusionsDiscrepancies between expected and actual utility of IRR affect the experiences of parents and families enrolled in genetic research studies. An informed consent process that fosters realistic expectations between researchers and participants may help to minimize any negative impact on parents and families.     

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The ability to resist hurricane damage is a property of both individuals and communities, and can have strong effects on the structure and function of many tropical forests. We examined the relative importance of tree size, species, biogeographic origin, local topography, and damage from previous storms in long‐term permanent plots in a rehabilitated subtropical moist forest in Puerto Rico following Hurricane Georges in order to better predict patterns of resistance. Severe damage included uprooted trees, snapped stems, or crowns with greater than 50 percent branch loss. Hurricane induced mortality after 21 mo was 5.2 percent/yr, more than seven times higher than background mortality levels during the nonhurricane periods. Species differed greatly in their mortality and damage patterns, but there was no relationship between damage and wood density or biogeographic origin. Rather, damage for a given species was correlated with mean annual increment, with faster growing species experiencing greater damage, suggesting that growth rate may reflect a variety of life history tradeoffs. Size was also predictive of damage, with larger trees suffering more damage. Trees on ridges and in valleys received greater damage than trees on slopes. A strong relationship was noted between previous hurricane damage and present structural damage, which could not solely be explained by the patterns with size and species. We suggest that resistance of trees to hurricane damage is therefore not only correlated with individual and species characteristics but also with past disturbance history, which suggests that in interpreting the effects of hurricanes on forest structure, individual storms cannot be treated as discrete, independent events.     

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Endogenously generated hydrogen peroxide induces apoptosis via mitochondrial damage independent of NF-kappaB and p53 activation in bovine embryos

Hydrogen peroxide (H(2)O(2)) has been implicated as a key molecule in arresting embryonic development; however, its mechanism of action is not fully established. The aim of the present study was to determine the chronological generation of H(2)O(2) from oocyte to morula, and to examine the relationship of H(2)O(2) with loss of mitochondrial membrane potential, nuclear factor kappa-B (NF-kappaB), p53, caspase-3 activation, and cell death in bovine embryos in vitro. Accordingly, superoxide anion radicals were detected between 32 and 120 h after in vitro fertilization, but higher percentages of oxygen radicals were found in non-competent embryos (n=73, 22 to 34%) than in competent embryos (n=73, 0 to 1%; P<0.005). Similarly, H(2)O(2) levels were higher in non-competent embryos (n=249, 39 to 71%) than in competent embryos (n=278, 0 to 3.4%) at all developmental stages tested (P<0.005). The percentage of cells with apoptotic morphology were higher in non-competent embryos (n=411, 3 to 54%) than in competent embryos (n=306, 0 to 0.6%; P<0.005). Based on assessment of mitochondrial membrane potential, competent embryos (n=305) had the highest percentages of JC-1 staining (31 to 50%) when compared with non-competent embryos (n=411; 1 to 15%, P<0.005). The percentage of activation of general caspases was different in non-competent embryos (n=291, 15 to 57%) when compared to competent embryos (n=304, 0 to 0.5%; P<0.005). Pharmacological inhibition of caspase-3, NF-kappaB and p53 triggered aberrant embryo cytoplasmic fragmentation with and without nuclei. We concluded that the sequential mechanism of O(2)(-) and H(2)O(2) generation, mitochondrial damage, caspase activation, and apoptotic morphology might be responsible for the developmental arrest of preimplantation embryos.     

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The last 20 years have seen lots of work in the area of surrogate marker validation, partly devoted to frame the evaluation in a multitrial framework, leading to definitions in terms of the quality of trial- and individual-level association between a potential surrogate and a true endpoint (Buyse et al., 2000, Biostatistics 1, 49-67). A drawback is that different settings have led to different measures at the individual level. Here, we use information theory to create a unified framework, leading to a definition of surrogacy with an intuitive interpretation, offering interpretational advantages, and applicable in a wide range of situations. Our method provides a better insight into the chances of finding a good surrogate endpoint in a given situation. We further show that some of the previous proposals follow as special cases of our method. We illustrate our methodology using data from a clinical study in psychiatry.     

Disruption of the cortical actin cytoskeleton does not affect store operated Ca2+ channels in human T-cells

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