Effects of increased temperature on plant communities depend on landscape location and precipitation

Global climate change is affecting and will continue to affect ecosystems worldwide. Specifically, temperature and precipitation are both expected to shift globally, and their separate and interactive effects will likely affect ecosystems differentially depending on current temperature, precipitation regimes, and other biotic and environmental factors. It is not currently understood how the effects of increasing temperature on plant communities may depend on either precipitation or where communities lie on soil moisture gradients. Such knowledge would play a crucial role in increasing our predictive ability for future effects of climate change in different systems. To this end, we conducted a multi‐factor global change experiment at two locations, differing in temperature, moisture, aspect, and plant community composition, on the same slope in the northern Mongolian steppe. The natural differences in temperature and moisture between locations served as a point of comparison for the experimental manipulations of temperature and precipitation. We conducted two separate experiments, one examining the effect of climate manipulation via open‐top chambers (OTCs) across the two different slope locations, the other a factorial OTC by watering experiment at one of the two locations. By combining these experiments, we were able to assess how OTCs impact plant productivity and diversity across a natural and manipulated range of soil moisture. We found that warming effects were context dependent, with the greatest negative impacts of warming on diversity in the warmer, drier upper slope location and in the unwatered plots. Our study is an important step in understanding how global change will affect ecosystems across multiple scales and locations.     

Evaluation of the Growth Assessment Protocol (GAP) for antenatal detection of small for gestational age: The DESiGN cluster randomised trial

BackgroundAntenatal detection and management of small for gestational age (SGA) is a strategy to reduce stillbirth. Large observational studies provide conflicting results on the effect of the Growth Assessment Protocol (GAP) in relation to detection of SGA and reduction of stillbirth; to the best of our knowledge, there are no reported randomised control trials. Our aim was to determine if GAP improves antenatal detection of SGA compared to standard care.Methods and findingsThis was a pragmatic, superiority, 2-arm, parallel group, open, cluster randomised control trial. Maternity units in England were eligible to participate in the study, except if they had already implemented GAP. All women who gave birth in participating clusters (maternity units) during the year prior to randomisation and during the trial (November 2016 to February 2019) were included. Multiple pregnancies, fetal abnormalities or births before 24⁺¹ weeks were excluded. Clusters were randomised to immediate implementation of GAP, an antenatal care package aimed at improving detection of SGA as a means to reduce the rate of stillbirth, or to standard care. Randomisation by random permutation was stratified by time of study inclusion and cluster size. Data were obtained from hospital electronic records for 12 months prerandomisation, the washout period (interval between randomisation and data collection of outcomes), and the outcome period (last 6 months of the study). The primary outcome was ultrasound detection of SGA (estimated fetal weight <10th centile using customised centiles (intervention) or Hadlock centiles (standard care)) confirmed at birth (birthweight <10th centile by both customised and population centiles). Secondary outcomes were maternal and neonatal outcomes, including induction of labour, gestational age at delivery, mode of birth, neonatal morbidity, and stillbirth/perinatal mortality. A 2-stage cluster–summary statistical approach calculated the absolute difference (intervention minus standard care arm) adjusted using the prerandomisation estimate, maternal age, ethnicity, parity, and randomisation strata. Intervention arm clusters that made no attempt to implement GAP were excluded in modified intention to treat (mITT) analysis; full ITT was also reported. Process evaluation assessed implementation fidelity, reach, dose, acceptability, and feasibility. Seven clusters were randomised to GAP and 6 to standard care. Following exclusions, there were 11,096 births exposed to the intervention (5 clusters) and 13,810 exposed to standard care (6 clusters) during the outcome period (mITT analysis). Age, height, and weight were broadly similar between arms, but there were fewer women: of white ethnicity (56.2% versus 62.7%), and in the least deprived quintile of the Index of Multiple Deprivation (7.5% versus 16.5%) in the intervention arm during the outcome period. Antenatal detection of SGA was 25.9% in the intervention and 27.7% in the standard care arm (adjusted difference 2.2%, 95% confidence interval (CI) −6.4% to 10.7%; p = 0.62). Findings were consistent in full ITT analysis. Fidelity and dose of GAP implementation were variable, while a high proportion (88.7%) of women were reached. Use of routinely collected data is both a strength (cost-efficient) and a limitation (occurrence of missing data); the modest number of clusters limits our ability to study small effect sizes.ConclusionsIn this study, we observed no effect of GAP on antenatal detection of SGA compared to standard care. Given variable implementation observed, future studies should incorporate standardised implementation outcomes such as those reported here to determine generalisability of our findings.Trial registrationThis trial is registered with the ISRCTN registry, ISRCTN67698474.

Matias C Vieira and colleagues evaluate the Growth Assessment Protocol (GAP) for antenatal detection of small for gestational age in the DESiGN cluster randomised trial.     

Regulation to Create Environments Conducive to Physical Activity: Understanding the Barriers and Facilitators at the Australian State Government Level

Introduction

Policy and regulatory interventions aimed at creating environments more conducive to physical activity (PA) are an important component of strategies to improve population levels of PA. However, many potentially effective policies are not being broadly implemented. This study sought to identify potential policy/regulatory interventions targeting PA environments, and barriers/facilitators to their implementation at the Australian state/territory government level.

Methods

In-depth interviews were conducted with senior representatives from state/territory governments, statutory authorities and non-government organisations (n = 40) to examine participants'': 1) suggestions for regulatory interventions to create environments more conducive to PA; 2) support for preselected regulatory interventions derived from a literature review. Thematic and constant comparative analyses were conducted.

Results

Policy interventions most commonly suggested by participants fell into two areas: 1) urban planning and provision of infrastructure to promote active travel; 2) discouraging the use of private motorised vehicles. Of the eleven preselected interventions presented to participants, interventions relating to walkability/cycling and PA facilities received greatest support. Interventions involving subsidisation (of public transport, PA-equipment) and the provision of more public transport infrastructure received least support. These were perceived as not economically viable or unlikely to increase PA levels. Dominant barriers were: the powerful ‘road lobby’, weaknesses in the planning system and the cost of potential interventions. Facilitators were: the provision of evidence, collaboration across sectors, and synergies with climate change/environment agendas.

Conclusion

This study points to how difficult it will be to achieve policy change when there is a powerful ‘road lobby’ and government investment prioritises road infrastructure over PA-promoting infrastructure. It highlights the pivotal role of the planning and transport sectors in implementing PA-promoting policy, however suggests the need for clearer guidelines and responsibilities for state and local government levels in these areas. Health outcomes need to be given more direct consideration and greater priority within non-health sectors.     

RAB-5- and RAB-11-dependent vesicle-trafficking pathways are required for plasma membrane repair after attack by bacterial pore-forming toxin

Sequence variation of antigenic proteins allows pathogens to evade antibody attack. The variable protein commonly includes a hypervariable region (HVR), which represents a key target for antibodies and is therefore predicted to be immunodominant. To understand the mechanism(s) of antibody evasion, we analyzed the clinically important HVR-containing M proteins of the human pathogen Streptococcus pyogenes. Antibodies elicited by M proteins were directed almost exclusively against the C-terminal part and not against the N-terminal HVR. Similar results were obtained for mice and humans with invasive S.?pyogenes infection. Nevertheless, only anti-HVR antibodies protected efficiently against infection, as shown by passive immunizations. The HVR fused to an unrelated protein elicited no antibodies, implying that it is inherently weakly immunogenic. These data indicate that the M protein HVR evades antibody attack not only through antigenic variation but also by weak immunogenicity, a paradoxical observation that may apply to other HVR-containing proteins.     

Protein Kinase D Promotes Airway Epithelial Barrier Dysfunction and Permeability through Down-regulation of Claudin-1

At the interface between host and external environment, the airway epithelium serves as a major protective barrier. In the present study we show that protein kinase D (PKD) plays an important role in the formation and integrity of the airway epithelial barrier. Either inhibition of PKD activity or silencing of PKD increased transepithelial electrical resistance (TEER), resulting in a tighter epithelial barrier. Among the three PKD isoforms, PKD3 knockdown was the most efficient one to increase TEER in polarized airway epithelial monolayers. In contrast, overexpression of PKD3 wild type, but not PKD3 kinase-inactive mutant, disrupted the formation of apical intercellular junctions and their reassembly, impaired the development of TEER, and increased paracellular permeability to sodium fluorescein in airway epithelial monolayers. We further found that overexpression of PKD, in particular PKD3, markedly suppressed the mRNA and protein levels of claudin-1 but had only minor effects on the expression of other tight junctional proteins (claudin-3, claudin-4, claudin-5, occludin, and ZO-1) and adherent junctional proteins (E-cadherin and β-catenin). Immunofluorescence study revealed that claudin-1 level was markedly reduced and almost disappeared from intercellular contacts in PKD3-overexpressed epithelial monolayers and that claudin-4 was also restricted from intercellular contacts and tended to accumulate in the cell cytosolic compartments. Last, we found that claudin-1 knockdown prevented TEER elevation by PKD inhibition or silencing in airway epithelial monolayers. These novel findings indicate that PKD negatively regulates human airway epithelial barrier formation and integrity through down-regulation of claudin-1, which is a key component of tight junctions.