Plant composition associated with environmental gradients in tropical montane forests (Cueva de Los Guacharos National Park,Huila, Colombia)

Niche differentiation among tropical forest plants can generate species turnover along gradients of soil, topography, climate, and land use history. In this study we explore the relative importance of these variables as drivers of floristic composition in Cueva de Los Guacharos National Park. We established twenty 0.1‐ha plots, within which trees, lianas, and shrubs (diameter ≥ 2.5 cm) were censused. We selected plot locations in primary and disturbed forests, and we measured topography and soil variables. Despite their structural similarity, primary and disturbed forests differed floristically, and also differed in environmental variables measured. A NMDS ordination showed that variation in the floristic composition across plots is highly correlated to the exchangeable acidity, elevation, temperature, and magnesium availability. Variance partitioning analysis shows that together spatial and environmental variables explain 24.2 percent of the variation in species composition. ‘Pure environmental’ variables were more important in explaining compositional variability than ‘pure spatial’ processes (9.8% and 1.4%, respectively). Residual variance may be attributed to stochastic process or non‐measured biotic effects.     

The earliest fossil evidence of bone boring by terrestrial invertebrates,examples from China and South Africa

We report the oldest fossil evidence of osteophagia by terrestrial invertebrates on both the Asian and African continents. Bones attributable to the Middle Jurassic dinosaur Chuanjiesaurus (Dinosauria: Sauropoda) were found with post-mortem insect modification in the Chuanjie Formation, Yunnan Province, China. The morphology of the borings closely matches the ichnogenus Cubiculum. Based on the lack of bioglyphs observed in Cubiculum ornatus, a new ichnospecies is proposed here. The new trace fossil, Cubiculum inornatus isp. nov., is interpreted to have been constructed for pupation by an unknown taxon of insect. Additionally, we report even older borings from Early Jurassic dinosaur bones of the Elliott Formation in the Karoo Basin, which represent the second oldest occurrence of insect traces in bone from continental settings. Both trace fossils sites have palaeogeographic implications for the origins and dispersal of osteophagia amongst terrestrial invertebrates during the Mesozoic. These discoveries push back the antiquity of pupation in animal bones by more than 100 million years to the Middle Jurassic, indicating that this behaviour, and osteophagy more generally, originated early in the Mesozoic, roughly comparable with the origination of insect pupation in woody substrates (Late Triassic).     

TIGIT Marks Exhausted T Cells,Correlates with Disease Progression,and Serves as a Target for Immune Restoration in HIV and SIV Infection

HIV infection induces phenotypic and functional changes to CD8⁺ T cells defined by the coordinated upregulation of a series of negative checkpoint receptors that eventually result in T cell exhaustion and failure to control viral replication. We report that effector CD8⁺ T cells during HIV infection in blood and SIV infection in lymphoid tissue exhibit higher levels of the negative checkpoint receptor TIGIT. Increased frequencies of TIGIT⁺ and TIGIT⁺ PD-1⁺ CD8⁺ T cells correlated with parameters of HIV and SIV disease progression. TIGIT remained elevated despite viral suppression in those with either pharmacological antiretroviral control or immunologically in elite controllers. HIV and SIV-specific CD8⁺ T cells were dysfunctional and expressed high levels of TIGIT and PD-1. Ex-vivo single or combinational antibody blockade of TIGIT and/or PD-L1 restored viral-specific CD8⁺ T cell effector responses. The frequency of TIGIT⁺ CD4⁺ T cells correlated with the CD4⁺ T cell total HIV DNA. These findings identify TIGIT as a novel marker of dysfunctional HIV-specific T cells and suggest TIGIT along with other checkpoint receptors may be novel curative HIV targets to reverse T cell exhaustion.     

Immunotherapy using algal‐produced Ara h 1 core domain suppresses peanut allergy in mice

Peanut allergy is an IgE‐mediated adverse reaction to a subset of proteins found in peanuts. Immunotherapy aims to desensitize allergic patients through repeated and escalating exposures for several months to years using extracts or flours. The complex mix of proteins and variability between preparations complicates immunotherapy studies. Moreover, peanut immunotherapy is associated with frequent negative side effects and patients are often at risk of allergic reactions once immunotherapy is discontinued. Allergen‐specific approaches using recombinant proteins are an attractive alternative because they allow more precise dosing and the opportunity to engineer proteins with improved safety profiles. We tested whether Ara h 1 and Ara h 2, two major peanut allergens, could be produced using chloroplast of the unicellular eukaryotic alga, Chlamydomonas reinhardtii. C. reinhardtii is novel host for producing allergens that is genetically tractable, inexpensive and easy to grow, and is able to produce more complex proteins than bacterial hosts. Compared to the native proteins, algal‐produced Ara h 1 core domain and Ara h 2 have a reduced affinity for IgE from peanut‐allergic patients. We further found that immunotherapy using algal‐produced Ara h 1 core domain confers protection from peanut‐induced anaphylaxis in a murine model of peanut allergy.     

Hepatic myelolipoma in two Goeldi's monkeys from South America held captive

Two cases of hepatic myelolipoma in Goeldi's monkeys from South America are described. One was a female evaluated due progressive abdominal distension. Ultrasound and computed tomography detected hepatic mass. Partial hepatectomy was performed, but the monkey died after surgery. Case 2 was a male that died suddenly, showing non‐specific clinical signs.