Biogeographical comparison of the emergent macrophyte, Sagittaria platyphylla in its native and introduced ranges

Understanding why some plant species become invasive is important to predict and prevent future weed threats and identify appropriate management strategies. Many hypotheses have been proposed to explain why plants become invasive, yet few studies have quantitatively compared plant and population parameters between native and introduced range populations to gain an objective perspective on the causes of plant invasion. The present study uses a biogeographical field survey to compare morphological and reproductive traits and abundance between the native range (USA) and two introduced ranges (Australia and South Africa) of Sagittaria platyphylla (Engelm.) J.G. Sm (Alismataceae), a highly invasive freshwater macrophyte. Introduced and native populations differed in sexual reproductive output with the number of achenes per fruiting head and individual achene weight found to be 40% and 50% greater in introduced populations respectively. However, no other morphological traits were found to be consistently different between the native and both introduced ranges, especially after taking into account differences in environmental conditions between the three ranges. Although populations in introduced regions were larger and occupied greater percentage cover, no differences in plant density were evident. Our results suggest that, apart from sexual reproduction, many of the trait patterns observed in S. platyphylla are influenced by environmental and habitat conditions within the native and invaded ranges. We conclude that the enemy release hypothesis best explains the results observed for sexual reproduction. In particular, we hypothesise that a release from natural enemies, specifically a pre-dispersal seed predator, may induce reproductive plasticity in S. platyphylla

Could enemy release explain invasion success of Sagittaria platyphylla in Australia and South Africa?.

Sagittaria platyphylla (delta arrowhead) is an emergent aquatic macrophyte native to southeastern United States of America that has been introduced into Australia and South Africa as an ornamental pond and aquarium plant. Compared to plants in the native range, S. platyphylla in the introduced range have greater reproductive capacity and form extensive infestations that dominate shallow waterbodies. One explanation for the invasive success of S. platyphylla in introduced countries is that plants are devoid of biotic pressures that would regulate population abundance in their native range (the enemy release hypothesis). We previously reported on field surveys that documented the number of pathogens and insect herbivores associated with S. platyphylla in native and introduced ranges. Here, we quantify the damage caused by these natural enemies to S. platyphylla in the two ranges. As predicted, damage to plants caused by pathogens and insect herbivores was much greater in the native than the introduced range at both the plant and population level. In introduced regions herbivory was low (less than 10%) in every plant part, while in North America insect damage to fruiting heads was 46% (of fruiting heads attacked), damage to leaves was between 33 to 57%, and internal herbivore damage to petioles and the inflorescence scapes was 56% and 43% respectively. Pathogen damage to leaves was between 39 to 57% of leaves per plant affected, compared to 9% in Australia and 8% in South Africa. This lack of biotic resistance from herbivores and disease may have facilitated S. platyphylla invasion in Australia and South Africa

Accelerator, reactor, solar and atmospheric neutrino oscillation: beyond three generations

We perform a phenomenological analysis of neutrino oscillation in a four generation framework introducing an additional sterile neutrino. In such a scenario, more than one pattern is possible that can accommodate three hieararchically different mass squared differences as required by the present experiments. We considered two different spectrums. Choosing the ${\Delta{m}}^2$s in the ranges suitable for the LSND, atmospheric and solar neutrino oscillation, limits on the mixing angles are derived, consistent with the most restrictive accelerator and reactor data as well as the atmospheric and solar neutrino results. The allowed mixing angles are found to be constrained very severely in both cases. For one mass pattern in the combined allowed zone the atmospheric anomaly can be explained by $\nu_e - \nu_{\mu}$ oscillation whereas for the other the $\nu_{\mu} - \nu_{\tau}$ channel is preferred. The accelerator experiments CHORUS and NOMAD have different sensitivities in these regions and they can distinguish between the two choices.Comment: Latex, 26 pages, 6 figures, 1 included in the Latex File, remaining 5 available on reques

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Temporal stability of the rumen microbiota in beef cattle, and response to diet and supplements

Acknowledgements Sampling of ruminal digesta was carried out at Scotland’s Rural College (SRUC) by Laura Nicoll, Lesley Deans and Claire Broadbent. Sequencing using Illumina MiSeq was carried out by Edinburgh Genomics, The University of Edinburgh. Edinburgh Genomics is partly supported through core grants from NERC (R8/H10/56), MRC (MR/K001744/1) and BBSRC (BB/J004243/1). Data were processed using the Maxwell High Performance Computing Cluster of the University of Aberdeen IT Service (www.abdn.ac.uk/staffnet/research/hpc.php), provided by Dell Inc. and supported by Alces Software. Funding This work was funded by the Rural and Environment Science and Analytical Services Division (RESAS) of the Scottish Government as a collaborative HEI project between The University of Aberdeen, The Roslin Institute, and Scotland’s Rural College (SRUC). The funding body had no role in the design of the study or collection, analysis, or interpretation of data or in writing the manuscript.Peer reviewedPublisher PD

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival