Soil legacies of tree species richness in a young plantation do not modulate tree seedling response to watering regime

Trees have a strong and species-specific influence on biotic and abiotic properties of the soil. Even after the vegetation is removed, the effect can persist to form so-called soil legacies. We investigated the effects of soil legacies of tree species richness on the emergence and growth of tree seedlings, and how these legacy effects modulate the seedling responses to irrigation frequency. We used a 9-year-old tree plantation on former agricultural land in Belgium, which is part of a biodiversity-ecosystem functioning experiment (FORBIO). Soil originating from monocultures and four-species plots, with different species combinations, was translocated to a greenhouse. Five tree species (Betula pendula, Fagus sylvatica, Pinus sylvestris, Quercus robur, and Tilia cordata) were sown and grown for one growing season in these soils. We performed a watering treatment (low and high irrigation frequency) to measure any potential interaction effects between the soil legacies and irrigation frequency. There was no evidence for soil legacy effects of species richness on plant performance or their response to the irrigation frequency. However, the effect of irrigation frequency was dependent on species identity of the tree seedlings. Despite the lack of clear legacy effects, performance measures did show correlated responses that are likely due to species composition effects. We ascribe these patterns to the young age of the forest and the agricultural past land use. At this early stage in forest development, the land-use history likely has a more important role in shaping soil characteristics that affect plant growth and their response to drought, than species diversity.

Novel multiparameter correlates of Coxiella burnetii infection and vaccination identified by longitudinal deep immune profiling

Q-fever is a flu-like illness caused by Coxiella burnetii (Cb), a highly infectious intracellular bacterium. There is an unmet need for a safe and effective vaccine for Q-fever. Correlates of immune protection to Cb infection are limited. We proposed that analysis by longitudinal high dimensional immune (HDI) profiling using mass cytometry combined with other measures of vaccination and protection could be used to identify novel correlates of effective vaccination and control of Cb infection. Using a vaccine-challenge model in HLA-DR transgenic mice, we demonstrated significant alterations in circulating T-cell and innate immune populations that distinguished vaccinated from naïve mice within 10 days, and persisted until at least 35 days post-vaccination. Following challenge, vaccinated mice exhibited reduced bacterial burden and splenomegaly, along with distinct effector T-cell and monocyte profiles. Correlation of HDI data to serological and pathological measurements was performed. Our data indicate a Th1-biased response to Cb, consistent with previous reports, and identify Ly6C, CD73, and T-bet expression in T-cell, NK-cell, and monocytic populations as distinguishing features between vaccinated and naïve mice. This study refines the understanding of the integrated immune response to Cb vaccine and challenge, which can inform the assessment of candidate vaccines for Cb.

Cultured human prostate-derived fibroblasts produce a factor that stimulates their growth with properties indistinguishable from basic fibroblast growth factor

Fibrostromal proliferation is believed to be important in the development of benign prostatic hyperplasia (BPH). We found that a mitogen for cultured mesodermal-derived cells was present in extracts of BPH tissue. The mitogen was identified as basic fibroblast growth factor (bFGF). Previous studies did not determine the cell population(s) responsible for bFGF production in the prostate. This information is important to the understanding of the role of bFGF in the etiology of BPH. Human prostate-derived fibroblasts (PF) were initiated in culture. Recombinant bFGF and PF lysates stimulated tritiated thymidine uptake by quiescent PF cells. Greater than 90% of the mitogen in PF lysates bound to heparin-Sepharose and had the same elution profile and apparent molecular weight as bFGF isolated from BPH tissue. The growth factor in PF lysates competed with recombinant iodinated bFGF for binding to antiserum to (1-24)bFGF. Cultured PF incorporated 35S-methionine into protein that was precipitated by antiserum to bFGF. The apparent molecular weight of the radiolabeled protein, about 17,000, was similar to authentic bFGF. The observations are consistent with the interpretation that cultured PF synthesize a growth factor that stimulates their growth with properties that are indistinguishable from bFGF.