Ecosystem engineering by seagrasses interacts with grazing to shape an intertidal landscape

Self-facilitation through ecosystem engineering (i.e., organism modification of the abiotic environment) and consumer-resource interactions are both major determinants of spatial patchiness in ecosystems. However, interactive effects of these two mechanisms on spatial complexity have not been extensively studied. We investigated the mechanisms underlying a spatial mosaic of low-tide exposed hummocks and waterlogged hollows on an intertidal mudflat in the Wadden Sea dominated by the seagrass Zostera noltii. A combination of field measurements, an experiment and a spatially explicit model indicated that the mosaic resulted from localized sediment accretion by seagrass followed by selective waterfowl grazing. Hollows were bare in winter, but were rapidly colonized by seagrass during the growth season. Colonized hollows were heavily grazed by brent geese and widgeon in autumn, converting these patches to a bare state again and disrupting sediment accretion by seagrass. In contrast, hummocks were covered by seagrass throughout the year and were rarely grazed, most likely because the waterfowl were not able to employ their preferred but water requiring feeding strategy ('dabbling') here. Our study exemplifies that interactions between ecosystem engineering by a foundation species (seagrass) and consumption (waterfowl grazing) can increase spatial complexity at the landscape leve

A life-history allele of large effect shortens developmental time in a wild insect population

Developmental time is a key life-history trait with large effects on Darwinian fitness. In many insects, developmental time is currently under strong selection to minimize ecological mismatches in seasonal timing induced by climate change. The genetic basis of responses to such selection, however, is poorly understood. To address this problem, we set up a long-term evolve-and-resequence experiment in the beetle Tribolium castaneum and selected replicate, outbred populations for fast or slow embryonic development. The response to this selection was substantial and embryonic developmental timing of the selection lines started to diverge during dorsal closure. Pooled whole-genome resequencing, gene expression analysis and an RNAi screen pinpoint a 222 bp deletion containing binding sites for Broad and Tramtrack upstream of the ecdysone degrading enzyme Cyp18a1 as a main target of selection. Using CRISPR/Cas9 to reconstruct this allele in the homogenous genetic background of a laboratory strain, we unravel how this single deletion advances the embryonic ecdysone peak inducing dorsal closure and show that this allele accelerates larval development but causes a trade-off with fecundity. Our study uncovers a life-history allele of large effect and reveals the evolvability of developmental time in a natural insect population.Animal science

Added value of co-morbidity in predicting health-related quality of life in COPD patients

AbstractThe extent to which a chronic obstructive pulmonary disease (COPD) patient is impaired in health-related quality of life (HRQoL) is only to a small extent reflected in clinical and demographical measures. As the influence of co-morbidity on HRQoL is less clear, we investigated the added value of 23 common diseases in predicting HRQoL in COPD patients with mild to severe airways obstruction.COPD patients from general practice who appeared to have an forced expiratory volume in 1 sec/inspiratory vital capacity (FEV1/IVC) < predicted −1·64 SD, FEV1<80% predicted, FEV1reversibility <12% and a smoking history, were included (n=163). HRQoL was assessed with the short-form-36 (SF-36) and the presence of co-morbidity was determined by a questionnaire, which asked for 23 common diseases.All domains of the SF-36 were best predicted by the presence of three or more co-morbid diseases. FEV1% predicted, dyspnoea and the presence of one or two diseases were second-best predictors. Co-morbidity explained an additional part of the variance in HRQoL, particularly for emotional functioning (ΔR2=0·11). When individual diseases were investigated, only insomnia appeared to be related to HRQoL.As HRQoL is still only partly explained, co-morbidity and other patient characteristics do not clearly distinguish between COPD patients with severe impairments in HRQoL and COPD patients with minor or no impairments in HRQoL. Therefore, it remains important to ask for problems in daily functioning and well-being, rather than to rely on patient characteristics alone

Towards global consensus on core outcomes for hidradenitis suppurativa research: an update from the HISTORIC consensus meetings I and II

Background A core outcomes set (COS) is an agreed minimum set of outcomes that should be measured and reported in all clinical trials for a specific condition. Hidradenitis suppurativa (HS) has no agreed‐upon COS. A central aspect in the COS development process is to identify a set of candidate outcome domains from a long list of items. Our long list had been developed from patient interviews, a systematic review of the literature and a healthcare professional survey, and initial votes had been cast in two e‐Delphi surveys. In this manuscript, we describe two in‐person consensus meetings of Delphi participants designed to ensure an inclusive approach to generation of domains from related items. Objectives To consider which items from a long list of candidate items to exclude and which to cluster into outcome domains. Methods The study used an international and multistakeholder approach, involving patients, dermatologists, surgeons, the pharmaceutical industry and medical regulators. The study format was a combination of formal presentations, small group work based on nominal group theory and a subsequent online confirmation survey. Results Forty‐one individuals from 13 countries and four continents participated. Nine items were excluded and there was consensus to propose seven domains: disease course, physical signs, HS‐specific quality of life, satisfaction, symptoms, pain and global assessments. Conclusions The HISTORIC consensus meetings I and II will be followed by further e‐Delphi rounds to finalize the core domain set, building on the work of the in‐person consensus meetings

What causes hidradenitis suppurativa ?—15 years after

The 14 authors of the first review article on hidradenitis suppurativa (HS) pathogenesis published 2008 in EXPERIMENTAL DERMATOLOGY cumulating from the 1st International Hidradenitis Suppurativa Research Symposium held March 30–April 2, 2006 in Dessau, Germany with 33 participants were prophetic when they wrote “Hopefully, this heralds a welcome new tradition: to get to the molecular heart of HS pathogenesis, which can only be achieved by a renaissance of solid basic HS research, as the key to developing more effective HS therapy.” (Kurzen et al. What causes hidradenitis suppurativa? Exp Dermatol 2008;17:455). Fifteen years later, th

Asthmatic airways obstruction assessment based on detailed analysis of respiratory sound spectra

This paper concerns the analysis of adventitious sounds produced by individual asthmatic patients, and relates the sounds to the degree of airways obstruction at the moment of sound recording. In this study, airways obstruction is represented by a parameter commonly used in clinical tests, the forced expiratory volume in one second. A nonrestrictive approach using spectral information in detail is followed, resulting in a fairly high resolution of respiration sounds with respect to airways obstruction. The beneficial effect of a power raising transformation is presented, together with an illumination of the background of this effec