Background:
Altered intestinal dendritic cell (DC) function underlies dysregulated T‐cell responses to bacteria in Crohn's disease (CD) but it is unclear whether composition of the intestinal ...microbiota impacts local DC function. We assessed the relationship between DC function with disease activity and intestinal microbiota in patients with CD.
Methods:
Surface expression of Toll‐like receptor (TLR)‐2, TLR‐4, and spontaneous intracellular interleukin (IL)‐10, IL‐12p40, IL‐6 production by freshly isolated DC were analyzed by multicolor flow cytometry of cells extracted from rectal tissue of 10 controls and 28 CD patients. Myeloid DC were identified as CD11c+HLA‐DR+lin‐/dim cells (lin = anti‐CD3, CD14, CD16, CD19, CD34). Intestinal microbiota were analyzed by fluorescent in situ hybridization of fecal samples with oligonucleotide probes targeting 16S rRNA of bifidobacteria, bacteroides‐prevotella, C. coccoides‐E. rectale, and Faecalibacterium prausnitzii.
Results:
DC from CD produced higher amounts of IL‐12p40 and IL‐6 than control DC. IL‐6+ DC were associated with the CD Activity Index (r = 0.425; P = 0.024) and serum C‐reactive protein (CRP) (r = 0.643; P = 0.004). DC expression of TLR‐4 correlated with disease activity. IL‐12p40+ DC correlated with ratio of bacteroides: bifidobacteria (r = 0.535, P = 0.003). IL‐10+ DC correlated with bifidobacteria, and IL‐6+ DC correlated negatively with F. prausnitzii (r = −0.50; P = 0.008). The amount of TLR‐4 on DC correlated negatively with the concentration of F. prausnitzii.
Conclusions:
IL‐6 production by intestinal DC is increased in CD and correlates with disease activity and CRP. Bacterially driven local IL‐6 production by intestinal DC may overcome regulatory activity, resulting in unopposed effector function and tissue damage. Intestinal DC function may be influenced by the composition of the commensal microbiota. (Inflamm Bowel Dis 2011;)
We mapped tidal wetland gross primary production (GPP) with unprecedented detail for multiple wetland types across the continental United States (CONUS) at 16‐day intervals for the years 2000–2019. ...To accomplish this task, we developed the spatially explicit Blue Carbon (BC) model, which combined tidal wetland cover and field‐based eddy covariance tower data into a single Bayesian framework, and used a super computer network and remote sensing imagery (Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index). We found a strong fit between the BC model and eddy covariance data from 10 different towers (r2 = 0.83, p < 0.001, root‐mean‐square error = 1.22 g C/m2/day, average error was 7% with a mean bias of nearly zero). When compared with NASA's MOD17 GPP product, which uses a generalized terrestrial algorithm, the BC model reduced error by approximately half (MOD17 had r2 = 0.45, p < 0.001, root‐mean‐square error of 3.38 g C/m2/day, average error of 15%). The BC model also included mixed pixels in areas not covered by MOD17, which comprised approximately 16.8% of CONUS tidal wetland GPP. Results showed that across CONUS between 2000 and 2019, the average daily GPP per m2 was 4.32 ± 2.45 g C/m2/day. The total annual GPP for the CONUS was 39.65 ± 0.89 Tg C/year. GPP for the Gulf Coast was nearly double that of the Atlantic and Pacific Coasts combined. Louisiana alone accounted for 15.78 ± 0.75 Tg C/year, with its Atchafalaya/Vermillion Bay basin at 4.72 ± 0.14 Tg C/year. The BC model provides a robust platform for integrating data from disparate sources and exploring regional trends in GPP across tidal wetlands.
Key Points
We created the Blue Carbon (BC) model, which mapped the Gross Primary Production (GPP) of all tidal wetlands within the continental United States
The BC model provides maps of tidal wetland GPP at sub‐250 m scales and at 16‐day intervals for the years 2000‐2019
The average daily GPP per m2 was 4.32 ± 2.45 g C/m2/day, and the total annual GPP for the continental United States was 39.65 ± 0.89 Tg C/year
Wetland ecosystems hold nearly a third of the global soil carbon pool, but as wetlands rapidly disappear the fate of this stored soil carbon is unclear. The aim of this study was to quantify and then ...link potential rates of microbial decomposition after vertical drowning of vegetated tidal marshes in coastal Louisiana to known drivers of anaerobic decomposition altered by vegetation loss. Profiles of potential CH4 and CO2 production (surface to 60 cm deep) were measured during anaerobic incubations, organic matter chemistry was assessed with infrared spectroscopy, and soil porewater nutrients and redox potentials were measured in the field along a chronosequence of wetland loss. After vertical drowning, pond soils had lower redox potentials, higher pH values, lower soil carbon and nitrogen concentrations, lower lignin: polysaccharide ratios, more NH4+ and PO43−, and higher rates of potential CO2 release than vegetated marsh soils. Potential CH4 production was similar in vegetated marshes and open water ponds, with depth‐dependent decreases in CH4 production as soil carbon concentrations increased. In these anoxic soils, vegetation loss exerts a primary control on decomposition rates because flooding drives sustained increases in porewater nutrient availability (NH4+ and PO43, dissolved organic carbon) and decreases in redox potential (from −150 to −500 mV) that lead to higher potential CO2 fluxes within a few years. Without new carbon inputs following wetland loss, the sustained decomposition in open water ponds may lead to losses of stored soil carbon and could influence global carbon budgets.
Plain Language Summary
Coastal wetlands capture and store large amounts of carbon in soil and vegetation, but wetland ecosystems are being lost at a rapid rate. Coastal wetlands like tidal marshes can be lost when they flood and sink, which kills the marsh grasses in a process called vertical drowning. We found that microbial production of greenhouse gases was higher after marshes in coastal Louisiana vertically drown. These potential soil carbon losses were related to changing environmental conditions caused by the loss of marsh grasses, specifically increases in nutrient and organic matter availability and decreases in soil reduction‐oxidation potential. A first impulse would be to think that at higher elevations, vegetated wetland soils would have faster rates of microbial decomposition than soils submerged under 10–70 cm of water. Our results show that the relationship between flooding and organic matter decomposition is more complex in tidal wetlands and suggest that faster decomposition rates combined with lower vegetation inputs following wetland loss could lead to sustained losses of previously stored soil carbon.
Key Points
The vertical drowning of coastal wetlands leads to stimulated rates of decomposition and higher production of CO2
Higher CO2 production is mediated by vegetation loss, which is associated with lower redox potential and greater nutrient availability
Without carbon inputs, sustained decomposition in open water ponds could lead to substantial losses of stored carbon
Although the concept of self-design is frequently employed in restoration, reestablishment of primary physical drivers does not always result in a restored ecosystem having the desired ecological ...functions that support system resilience and stability. We investigated the use of a primary environmental driver in coastal salt marshes, sediment availability, as a means of promoting the resilience and stability of submerging deltaic salt marshes, which are rapidly subsiding due to natural and human-induced processes. We conducted a disturbance-–recovery experiment across a gradient of sediment slurry addition to assess the roles of sediment elevation and soil physico-chemical characteristics on vegetation resilience and stability in two restored salt marshes of differing age (a 15-year-old site and a 5-year-old site).
Salt marshes that received moderate intensities of sediment slurry addition with elevations at the mid to high intertidal zone (2-–11 cm above local mean sea level; MSL) were more resilient than natural marshes. The primary regulator of enhanced resilience and stability in the restored marshes was the alleviation of flooding stress observed in the natural, unsubsidized marsh. However, stability reached a sediment addition threshold, at an elevation of 11 cm above MSL, with decreasing stability in marshes above this elevation. Declines in resilience and stability above the sediment addition threshold were principally influenced by relatively dry conditions that resulted from insufficient and infrequent flooding at high elevations. Although the older restored marsh has subsided over time, areas receiving too much sediment still had limited stability 15 years later, emphasizing the importance of applying the appropriate amount of sediment to the marsh. In contrast, treated marshes with elevations 2-–11 cm above MSL were still more resilient than the natural marsh 15 years after restoration, illustrating that when performed correctly, sediment slurry addition can be a sustainable restoration technique.
Despite declining incidence in most high-income countries, tuberculosis shows no signs of disappearing in the near future. Although surveillance data from most Western European countries show ...relatively stable declines in the rate of tuberculosis over the past several decades, some have reported either an increasing rate or a decelerating pace of reduction in recent years. The burden of disease now disproportionately affects high-risk groups such as migrants, homeless persons, and prisoners. In view of the concentration of cases in urban areas and high-risk deprived groups, interventions that may not be efficient when applied to the general population may be highly cost effective when targeted at high-risk groups. In this article, we examine some controversial elements of tuberculosis prevention and control in low-burden countries and recommend issues for further research. In particular, we assess current evidence on the duration of protection by BCG vaccine, the screening of migrants and hard-to-reach groups, and the use of preventive therapy for contacts of cases of infectious multidrug-resistant tuberculosis. This analysis is presented from the perspective of low-tuberculosis-burden, high-income countries attempting to eliminate tuberculosis.
Reports of ChAdOx1 vaccine-associated thrombocytopenia and vascular adverse events have led to some countries restricting its use. Using a national prospective cohort, we estimated associations ...between exposure to first-dose ChAdOx1 or BNT162b2 vaccination and hematological and vascular adverse events using a nested incident-matched case-control study and a confirmatory self-controlled case series (SCCS) analysis. An association was found between ChAdOx1 vaccination and idiopathic thrombocytopenic purpura (ITP) (0-27 d after vaccination; adjusted rate ratio (aRR) = 5.77, 95% confidence interval (CI), 2.41-13.83), with an estimated incidence of 1.13 (0.62-1.63) cases per 100,000 doses. An SCCS analysis confirmed that this was unlikely due to bias (RR = 1.98 (1.29-3.02)). There was also an increased risk for arterial thromboembolic events (aRR = 1.22, 1.12-1.34) 0-27 d after vaccination, with an SCCS RR of 0.97 (0.93-1.02). For hemorrhagic events 0-27 d after vaccination, the aRR was 1.48 (1.12-1.96), with an SCCS RR of 0.95 (0.82-1.11). A first dose of ChAdOx1 was found to be associated with small increased risks of ITP, with suggestive evidence of an increased risk of arterial thromboembolic and hemorrhagic events. The attenuation of effect found in the SCCS analysis means that there is the potential for overestimation of the reported results, which might indicate the presence of some residual confounding or confounding by indication. Public health authorities should inform their jurisdictions of these relatively small increased risks associated with ChAdOx1. No positive associations were seen between BNT162b2 and thrombocytopenic, thromboembolic and hemorrhagic events.
Highlights • A review of technical aspects of transcranial electrical stimulation (tES) techniques. • Recommendations for safe and replicable application of tDCS and other tES methods. • Discussion ...of state-of-the-art methodology and design considerations in tES.
Noninvasive neuromodulatory techniques such as transcranial direct current stimulation (tDCS) are attracting increasing interest as potential therapies for a wide range of neurological and ...psychiatric conditions. When targeted to the dorsolateral prefrontal cortex (DLPFC), anodal, facilitatory tDCS has been shown to improve symptoms in a range of domains including working memory, mood, and pain perception (Boggio et al., 2008a; Dockery et al., 2009; Kalu et al., 2012). However, the mechanisms underlying these promising behavioral effects are not well understood. Here, we investigated brain perfusion changes, as assessed using whole-brain arterial spin labeling (ASL), during tDCS applied to the left DLPFC in healthy humans. We demonstrated increased perfusion in regions closely anatomically connected to the DLPFC during anodal tDCS in conjunction with a decreased functional coupling between the left DLPFC and the thalami bilaterally. Despite highly similar effects on cortical excitability during and after stimulation (Nitsche and Paulus, 2000, 2001), cortical perfusion changes were markedly different during these two time periods, with widespread decreases in cortical perfusion being demonstrated after both anodal and cathodal tDCS compared to the period during stimulation. These findings may at least partially explain the different effects on behavior in these time periods described previously in the motor system (Stagg et al., 2011). In addition, the data presented here provide mechanistic explanations for the behavioral effects of anodal tDCS applied to the left DLPFC in terms of modulating functional connectivity between the DLPFC and thalami, as has been hypothesized previously (Lorenz et al., 2003).
Mangrove forests are highly productive tidal saline wetland ecosystems found along sheltered tropical and subtropical coasts. Ecologists have long assumed that climatic drivers (i.e., temperature and ...rainfall regimes) govern the global distribution, structure, and function of mangrove forests. However, data constraints have hindered the quantification of direct climate—mangrove linkages in many parts of the world. Recently, the quality and availability of global-scale climate and mangrove data have been improving. Here, we used these data to better understand the influence of air temperature and rainfall regimes upon the distribution, abundance, and species richness of mangrove forests. Although our analyses identify global-scale relationships and thresholds, we show that the influence of climatic drivers is best characterized via regional range-limit-specific analyses. We quantified climatic controls across targeted gradients in temperature and/or rainfall within 14 mangrove distributional range limits. Climatic thresholds for mangrove presence, abundance, and species richness differed among the 14 studied range limits. We identified minimum temperature-based thresholds for range limits in eastern North America, eastern Australia, New Zealand, eastern Asia, eastern South America, and southeast Africa. We identified rainfall-based thresholds for range limits in western North America, western Gulf of Mexico, western South America, western Australia, Middle East, northwest Africa, east central Africa, and west-central Africa. Our results show that in certain range limits (e.g., eastern North America, western Gulf of Mexico, eastern Asia), winter air temperature extremes play an especially important role. We conclude that rainfall and temperature regimes are both important in western North America, western Gulf of Mexico, and western Australia. With climate change, alterations in temperature and rainfall regimes will affect the global distribution, abundance, and diversity of mangrove forests. In general, warmer winter temperatures are expected to allow mangroves to expand poleward at the expense of salt marshes. However, dispersal and habitat availability constraints may hinder expansion near certain range limits. Along arid and semiarid coasts, decreases or increases in rainfall are expected to lead to mangrove contraction or expansion, respectively. Collectively, our analyses quantify climate–mangrove linkages and improve our understanding of the expected global- and regional-scale effects of climate change upon mangrove forests.
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