Stress and Adiposity: A Meta‐Analysis of Longitudinal Studies

Psychosocial stress has been strongly implicated in the biology of adiposity but epidemiological studies have produced inconsistent results. The aim of this analysis was to bring together results from published, longitudinal, prospective studies examining associations between psychosocial stress and objectively measured adiposity in a meta‐analysis. Searches were conducted on Medline, PsycINFO, Web of Science, and PubMed (to January 2009) and reference lists from relevant articles were examined. Prospective studies relating psychosocial stress (general life stress (including caregiver stress), work stress) to BMI, body fat, body weight, waist circumference, or waist‐to‐hip ratio were included. Analyses from 14 cohorts were collated and evaluated. There was no significant heterogeneity, no evidence of publication bias, and no association between study quality and outcomes. The majority of analyses found no significant relationship between stress and adiposity (69%), but among those with significant effects, more found positive than negative associations (25 vs. 6%). Combining results in a meta‐analysis showed that stress was associated with increasing adiposity (r = 0.014; confidence interval (CI) = 0.002–0.025, P < 0.05). Effects were stronger for men than women, in analyses with longer rather than shorter follow‐ups, and in better quality studies. We conclude that psychosocial stress is a risk factor for weight gain but effects are very small. Variability across studies indicates there are moderating variables to be elucidated.     

Radiofibrinogen catabolism in nephritis.

A radiofibrinogen catabolism study performed on 40 patients with glomerulonephritis has shown increased fibrinogen catabolism in active immune-complex disorders.     

Empirical and theoretical challenges in aboveground–belowground ecology

A growing body of evidence shows that aboveground and belowground communities and processes are intrinsically linked, and that feedbacks between these subsystems have important implications for community structure and ecosystem functioning. Almost all studies on this topic have been carried out from an empirical perspective and in specific ecological settings or contexts. Belowground interactions operate at different spatial and temporal scales. Due to the relatively low mobility and high survival of organisms in the soil, plants have longer lasting legacy effects belowground than aboveground. Our current challenge is to understand how aboveground–belowground biotic interactions operate across spatial and temporal scales, and how they depend on, as well as influence, the abiotic environment. Because empirical capacities are too limited to explore all possible combinations of interactions and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground–belowground approach offers perspectives for enhancing ecological understanding, namely succession, agro-ecosystems, biological invasions and global change impacts on ecosystems. In plant succession, differences in scales between aboveground and belowground biota, as well as between species interactions and ecosystem processes, have important implications for the rate and direction of community change. Aboveground as well as belowground interactions either enhance or reduce rates of plant species replacement. Moreover, the outcomes of the interactions depend on abiotic conditions and plant life history characteristics, which may vary with successional position. We exemplify where translation of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects of global change on community re-organisation and ecosystem processes.     

Determining the impact of scale insect honeydew, and invasive wasps and rodents, on the decomposer subsystem in a New Zealand beech forest

Relatively few studies have considered how aboveground invasive consumers influence decomposer communities. We investigated the potential effects of three types of animals on the decomposer subsystem in a floristically simple New Zealand Nothofagus forest. These animals are the native beech honeydew scale insect (Ultracoelostoma spp.) that secretes large amounts of sugar-rich honeydew that washes to the soil, invasive social wasps (Vespula spp.) that remove honeydew and prevent it from reaching the ground, and invasive rodents (the house mouse (Mus musculus) and ship rat (Rattus rattus)) that are predators of litter invertebrates. We performed a 4 years manipulative experiment involving addition of synthetic honeydew to the soil surface at amounts equal to that washed to the soil both in the absence and presence of wasps. All treatments were subjected to both exclusion and non-exclusion of rodents. Full honeydew addition influenced several components of the belowground community (both positively and negatively), and promoted fungi and fungal feeding fauna at the expense of bacteria and bacterial-feeders. The reduced addition of honeydew (representing effects of wasps) reversed some (but not all) effects of full honeydew addition. Rodents also influenced some belowground organisms, often reversing the effects of honeydew addition. The honeydew levels simulating wasp effects and the presence of rodents both greatly promoted humus carbon and nutrient storage relative to all other treatments, highlighting that invaders can alter soil carbon sequestration and nutrient capital. Our study points to invasive animals modifying the effects of a native animal on multiple components of the decomposer subsystem.     

Genomic analysis of a novel spontaneous albino C57BL/6N mouse strain

We report an albino C57BL/6N mouse strain carrying a spontaneous mutation in the tyrosinase gene (C57BL/6N‐Tyr^cWTSI). Deep whole genome sequencing of founder mice revealed very little divergence from C57BL/6NJ and C57BL/6N (Taconic). This coisogenic strain will be of great utility for the International Mouse Phenotyping Consortium (IMPC), which uses the EUCOMM/KOMP targeted C57BL/6N ES cell resource, and other investigators wishing to work on a defined C57BL/6N background. genesis 51:523–528. © 2013 The Authors. Genesis Published by Wiley Periodicals, Inc.