Small Mammal Activity Alters Plant Community Composition and Microbial Activity in an Old-Field Ecosystem

Herbivores modify their environment by consuming plant biomass and redistributing materials across the landscape. While small mammalian herbivores, such as rodents, are typically inconspicuous, their impacts on plant community structure and chemistry can be large. We used a small mammal exclosure experiment to explore whether rodents in a southeastern old field directly altered the above ground plant species composition and chemistry, and indirectly altered the below ground soil community composition and activity. In general, when rodents were excluded, C3 graminoids increased in cover and biomass, contributing toward a shift in plant species composition relative to plots where rodents were present. The plant community chemistry also shifted; plant fiber concentration and carbon : nitrogen were higher, whereas plant nitrogen concentration was lower in exclosure plots relative to access plots. While microbial community enzyme activity increased when rodents were excluded, no significant changes in the fungal : bacterial or potential nitrogen mineralization occurred between treatments. Our results show that rodents can rapidly influence aboveground plant community composition and chemistry, but their influence on below ground processes may require plant inputs to the soil to accumulate over longer periods of time

Nonadherence to systemic immune-modifying therapy in people with psoriasis during the COVID-19 pandemic : Findings from a global cross-sectional survey

Nonadherence to immune-modifying therapy is a complex behaviour which, before the COVID-19 pandemic, was shown to be associated with mental health disorders in people with immune-mediated diseases. The COVID-19 pandemic has led to a rise in the global prevalence of anxiety and depression, and limited data exist on the association between mental health and nonadherence to immune-modifying therapy during the pandemic. To assess the extent of and reasons underlying nonadherence to systemic immune-modifying therapy during the COVID-19 pandemic in individuals with psoriasis, and the association between mental health and nonadherence. Online self-report surveys (PsoProtectMe), including validated screens for anxiety and depression, were completed globally during the first year of the pandemic. We assessed the association between anxiety or depression and nonadherence to systemic immune-modifying therapy using binomial logistic regression, adjusting for potential cofounders (age, sex, ethnicity, comorbidity) and country of residence. Of 3980 participants from 77 countries, 1611 (40.5%) were prescribed a systemic immune-modifying therapy. Of these, 408 (25.3%) reported nonadherence during the pandemic, most commonly due to concerns about their immunity. In the unadjusted model, a positive anxiety screen was associated with nonadherence to systemic immune-modifying therapy [odds ratio (OR) 1.37, 95% confidence interval (CI) 1.07-1.76]. Specifically, anxiety was associated with nonadherence to targeted therapy (OR 1.41, 95% CI 1.01-1.96) but not standard systemic therapy (OR 1.16, 95% CI 0.81-1.67). In the adjusted model, although the directions of the effects remained, anxiety was not significantly associated with nonadherence to overall systemic (OR 1.20, 95% CI 0.92-1.56) or targeted (OR 1.33, 95% CI 0.94-1.89) immune-modifying therapy. A positive depression screen was not strongly associated with nonadherence to systemic immune-modifying therapy in the unadjusted (OR 1.22, 95% CI 0.94-1.57) or adjusted models (OR 1.14, 95% CI 0.87-1.49). These data indicate substantial nonadherence to immune-modifying therapy in people with psoriasis during the pandemic, with attenuation of the association with mental health after adjusting for confounders. Future research in larger populations should further explore pandemic-specific drivers of treatment nonadherence. Clear communication of the reassuring findings from population-based research regarding immune-modifying therapy-associated adverse COVID-19 risks to people with psoriasis is essential, to optimize adherence and disease outcomes

Network analysis of the transcriptional pattern of young and old cells of Escherichia coli during lag phase

Background: The aging process of bacteria in stationary phase is halted if cells are subcultured and enter lag phase and it is then followed by cellular division. Network science has been applied to analyse the transcriptional response, during lag phase, of bacterial cells starved previously in stationary phase for 1 day (young cells) and 16 days (old cells). Results: A genome scale network was constructed for E. coli K-12 by connecting genes with operons, transcription and sigma factors, metabolic pathways and cell functional categories. Most of the transcriptional changes were detected immediately upon entering lag phase and were maintained throughout this period. The lag period was longer for older cells and the analysis of the transcriptome revealed different intracellular activity in young and old cells. The number of genes differentially expressed was smaller in old cells (186) than in young cells (467). Relatively, few genes (62) were up- or down-regulated in both cultures. Transcription of genes related to osmotolerance, acid resistance, oxidative stress and adaptation to other stresses was down-regulated in both young and old cells. Regarding carbohydrate metabolism, genes related to the citrate cycle were up-regulated in young cells while old cells up-regulated the Entner Doudoroff and gluconate pathways and down-regulated the pentose phosphate pathway. In both old and young cells, anaerobic respiration and fermentation pathways were down-regulated, but only young cells up-regulated aerobic respiration while there was no evidence of aerobic respiration in old cells.Numerous genes related to DNA maintenance and replication, translation, ribosomal biosynthesis and RNA processing as well as biosynthesis of the cell envelope and flagellum and several components of the chemotaxis signal transduction complex were up-regulated only in young cells. The genes for several transport proteins for iron compounds were up-regulated in both young and old cells. Numerous genes encoding transporters for carbohydrates and organic alcohols and acids were down-regulated in old cells only. Conclusion: Network analysis revealed very different transcriptional activities during the lag period in old and young cells. Rejuvenation seems to take place during exponential growth by replicative dilution of old cellular components

Deletion of transketolase triggers a stringent metabolic response in promastigotes and loss of virulence in amastigotes of Leishmania mexicana

Transketolase (TKT) is part of the non-oxidative branch of the pentose phosphate pathway (PPP). Here we describe the impact of removing this enzyme from the pathogenic protozoan Leishmania mexicana. Whereas the deletion had no obvious effect on cultured promastigote forms of the parasite, the Δtkt cells were not infective to mice. Δtkt promastigotes were more susceptible to oxidative stress and various leishmanicidal drugs than wild-type, and metabolomics analysis revealed profound changes to metabolism in these cells. In addition to changes consistent with those directly related to the role of TKT in the PPP, central carbon metabolism was substantially decreased, the cells consumed significantly less glucose, flux through glycolysis diminished, and production of the main end products of metabolism was decreased. Only minor changes in RNA abundance from genes encoding enzymes in central carbon metabolism, however, were detected although fructose-1,6-bisphosphate aldolase activity was decreased two-fold in the knock-out cell line. We also showed that the dual localisation of TKT between cytosol and glycosomes is determined by the C-terminus of the enzyme and by engineering different variants of the enzyme we could alter its sub-cellular localisation. However, no effect on the overall flux of glucose was noted irrespective of whether the enzyme was found uniquely in either compartment, or in both

Trade-off between microbial carbon use efficiency and specific nutrient-acquiring extracellular enzyme activities under reduced oxygen

• Reduced oxygen increased microbial metabolic quotient (qCO2). • Reduced oxygen enhanced microbial specific C-, N- and P-acquiring enzyme activity. • Reduced oxygen increased microbial C relative to N and P limitation. • Reduced oxygen increased microbial N relative to P limitation. • Specific enzyme activity was positively related to qCO2 under reduced oxygen. Mangroves are one of the most ecologically sensitive ecosystems to global climate change, which have cascading impacts on soil carbon (C), nitrogen (N) and phosphorus (P) cycling. Moreover, mangroves are experiencing increasing N and P loadings and reduced oxygen availability due to intensified climate change and human activities. However, both direct and interactive effects of these perturbations on microbially mediated soil C, N and P cycling are poorly understood. Here, we simultaneously investigated the effects of N and P loadings and reduced oxygen on microbial biomass, microbial respiration, and extracellular enzyme activities (EEAs) in mangrove soils. We calculated the microbial metabolic quotient (qCO2), which is regarded as a useful inverse metric of microbial C use efficiency (CUE). Our results show that reduced oxygen significantly increases both qCO2 and microbial specific EEAs (enzyme activity per unit of microbial biomass) for C-, N- and P-acquisition regardless of N or P loadings. Furthermore, we found that qCO2 positively correlated with microbial specific EEAs under reduced oxygen, whereas no clear relationship was detected under ambient oxygen. These results suggest that reduced oxygen increases microbial specific EEAs at the expense of increasing microbial respiration per unit biomass, indicating higher energy cost per unit enzyme production

The Passive Arbiter: Litigants in Person and the Challenge to Neutrality

This article examines the challenges posed to judgecraft by litigants in person. It draws on significant empirical evidence from a study conducted by the author in England and Wales demonstrating the challenges posed by litigants in person to judges and the courts. It argues that a central concept behind traditional notions of judging, that of judge as passive arbiter, inhibits fair and effective adjudication. From an analysis of this evidence, it critiques the theoretical foundations of the passive arbiter and suggests an alternative approach to judging be formulated based on principle-based communication, a simpler, more empathetic and cognitively open approach to managing hearings prior to the actual judicial decision

Critical pathways programme: Unravelling sub-catchment scale nitrogen delivery to waterways

To be effective and efficient, decision making on land use, land management, mitigation measures, as well as policy, need to be based on a clear understanding of cause-effect relationships. Present practice is to link activities on the land and water quality outcomes at spatial scales of 100s to 1000s of km². However, such large catchments are inevitably heterogeneous. Consequently, it is exceptionally difficult to link an observed contaminant flux at the catchment outlet to the many past and present activities within the large catchment that collectively have caused it. The need to focus on the sub-catchment scale (10s of km²), i.e. the local streams that feed the large rivers that are typically being monitored has therefore recently been emphasised internationally. To unravel sub-catchment scale nitrogen delivery to waterways, we are introducing an innovative multi-scale measurement, data analysis and modelling approach that allows to coherently link transect, sub-catchment and catchment scale hydrogeophysical information. Three key innovations will collectively enable us to achieve this. Firstly, we will introduce a novel geophysical measurement suite (airborne and ground-based) to gain information on structural, hydrological, and chemical characteristics controlling N transport and attenuation, particularly in the shallow subsurface zone (top 20m). Secondly, innovative Environmental Data Analytics (EDA) techniques will be used to integrate the information from the ‘Big Data’ created by the new geophysical measurements. Thirdly, we will use the hydrogeophysical units, identified by EDA together with Lidar to conceptualise and develop a numerical structure for catchment-scale flow models. To simulate the sub-catchment scale flow, transport, and attenuation, we will nest finer resolution models within the coarser catchment models using information gathered at the sub-catchment scale. Two intensively farmed catchments with contrasting hydrological and biogeochemical conditions provide our case studies. The Waiotapu Stream catchment (≈ 312 km²) on the North Island’s Central Plateau represents a baseflow-dominated upland catchment with a 2 large groundwater reservoir in young volcanic deposits. In contrast, the Piako River headwater catchment is a lowland catchment (≈ 104 km² ) in the upper Hauraki Plains with aquifer deposits of lower transmissivity and a high quickflow fraction in the flow hydrograph