Mesopelagic microbial carbon production correlates with diversity across different marine particle fractions

The vertical flux of marine snow particles significantly reduces atmospheric carbon dioxide concentration. In the mesopelagic zone, a large proportion of the organic carbon carried by sinking particles dissipates thereby escaping long term sequestration. Particle associated prokaryotes are largely responsible for such organic carbon loss. However, links between this important ecosystem flux and ecological processes such as community development of prokaryotes on different particle fractions (sinking vs. non-sinking) are yet virtually unknown. This prevents accurate predictions of mesopelagic organic carbon loss in response to changing ocean dynamics. Using combined measurements of prokaryotic heterotrophic production rates and species richness in the North Atlantic, we reveal that carbon loss rates and associated microbial richness are drastically different with particle fractions. Our results demonstrate a strong negative correlation between prokaryotic carbon losses and species richness. Such a trend may be related to prokaryotes detaching from fast-sinking particles constantly enriching non-sinking associated communities in the mesopelagic zone. Existing global scale data suggest this negative correlation is a widespread feature of mesopelagic microbes

Effects of nickel oxide nanoparticles on survival, reproduction, and oxidative stress biomarkers in the marine calanoid copepod Centropages ponticus under short-term exposure

Excessive use of nickel oxide nanoparticles (NiO NPs) in various industrial and commercial products can lead to various negative effects in human and environmental health due to their possible discharge into the environment. Nerveless, information about their ecotoxicological effects on marine organisms are lacking. Copepods are good ecotoxicological models because of their high sensitivity to environmental stress and their key role in the marine food webs. In this study, 48 h acute tests were conducted on the marine planktonic copepod Centropages ponticus to assess lethal and sublethal toxicities of NiO NPs. The results revealed LC50 (48 h) of 4 mg/L for adult females. Aggregation and settling of NiO NPs were observed at concentrations >= 2 mg/L. Exposure to sublethal concentrations (>= 0.02 mg/L for 48 h) had significant negative effects on reproductive success in C. ponticus. Egg production after 24 h and 48 h decreased by 32% and 46%, respectively at 0.02 mg/L and 70% and 82%, respectively, at 2 mg/L. Hatching success was reduced by 70% and 79% at 2 mg/L for eggs produced after 24 h and 48 h respectively. Antioxidant enzymatic activity increased significantly with NiO NP concentration and time, indicating that NiO NPs can cause oxidative stress in C. ponticus even under short-term exposure, while significant inhibition of acetylcholinesterase activity at 2 mg/L after 48 h suggests neurotoxic effects of NiO NPs

Description of participants in the "Atout Age Mobility" prevention workshops at the University Hospital Center of La Réunion : a prospective study

Introduction As the population ages, loss of autonomy is becoming a priority public health issue. "Atout Age Mobility" prevention interventions for seniors aim to limit frailty, which is a predictive and reversible factor in the loss of autonomy and disability. Objectives The objective of this study is to describe the impact of these interventions on the physical performance and quality of life of a pilot sample of participants. Design We conducted a prospective study named 5P PILOT with 3 months of follow up. Settings Subjects were recruited by convenience sampling from participants in the "Atout Age Mobility" workshops at Saint Joseph from 04/09/2017 to 29/01/2019. Participants Retired people over 55 years old with no contraindications to physical activity recruited from participants in the "Atout Age Mobility" workshops in Saint Joseph. Intervention(s) (for clinical trials) or Exposure(s) (for observational studies): All participants completed 12 weeks of physical exercise called the "Atout Age Mobility" workshop, which lasted 60 minutes each week and was supervised by physical activity coaches. Main Outcome(s) and Measure(s) Physical performance was assessed by Short physical performance battery (SPPB), 10-m gait speed and grip strength measurement. Quality of life through the SF-36 test. Results Ninety-six patients were included and 55 (57.3%) completed the study. There was a significant improvement in gait speed (1.35 +/- 0.26m/s vs. 1.27 +/- 0.24m/s; p=0.008). There was no significant change in SF-36, grip strength dominant arm and SPPB at the 0.01 significance level. Conclusion The "Atout Ages Mobility" workshops seem to significantly improve gait speed but not other aspects of physical performance or quality of life

Experimental and modelling evidence of splash effects on manure borne Escherichia coli washoff

In tropical montane South-East Asia, recent changes in land use have induced increased runoff, soil erosion and in-stream suspended sediment loads. Land use change is also contributing to increased microbial pathogen dissemination and contamination of stream waters. Escherichia coli (E. coli) is frequently used as an indicator of faecal contamination. Field rain simulations were conducted to examine how E. coli is exported from the surface of upland, agricultural soils during runoff events. The objectives were to characterize the loss dynamics of this indicator from agricultural soils contaminated with livestock waste, and to identify the effect of splash on washoff. Experiments were performed on nine 1 m(2) plots, amended or not with pig or poultry manure. Each plot was divided into two 0.5 m(2) sub-plots. One of the two sub-plots was protected with a mosquito net for limiting the raindrop impact effects. Runoff, soil detachment by raindrop impact and its entrainment by runoff, and E. coli loads and discharge were measured for each sub-plot. The results show that raindrop impact strongly enhances runoff generation, soil detachment and entrainment and E. coli export. When the impact of raindrops was reduced with a mosquito net, total runoff was reduced by more than 50%, soil erosion was on average reduced by 90% and E. coli export from the amended soil surface was on average 3 to 8 times lower. A coupled physics-based approach was performed using the Cast3M platform for modelling the time evolutions of runoff, solid particles detachment and transfer and bacteria transport that were measured for one of the nine plots. After estimation of the saturated hydraulic conductivity, soil erodibility and attachment rate of bacteria, model outputs were consistent with measured runoff coefficients, suspended sediment and E. coli loads. This work therefore underlines the need to maintain adequate vegetation at the soil surface to avoid the erosion and export of soil borne potential pathogens towards downstream aquatic systems

Would we recover better sleep at the end of Covid-19 ? A relative improvement observed at the population level with the end of the lockdown in France

Background: The outbreak of the Covid-19 pandemic and the accompanying lockdown measures have had a major impact on societies around the world, leading to sleep problems for a large part of the population. In order to assess the sustainability of sleeping troubles related to the sanitary crisis, it was crucial to measure its prevalence after the end of the Covid-19 confinement. Methods: As part of an epidemiological survey on Covid and Confinement (COCONEL), we enquired on sleep disorders using two items in 4 repetitive cross-sectional surveys. The first took place during the first week of the French confinement (March 31 to April 2; N = 1005 participants). The second took place in the middle of this period (April 15-17; N = 1005). The two last surveys were held at the end of the confinement (May 7-10; N = 2003) and one month after the end (June 10-12; N = 1736). Using a random constant, the mixed model took into account the longitudinal character of the last two waves (intra-individual correlations for individuals surveyed in waves 3 and 4). Results: The prevalence of sleep problems significantly decreased during the last weeks of the confinement, and this trend was confirmed one month after the end of confinement. One quarter of the population reported that their sleep was better one month after the end of the confinement. Sleep improvement was reported more often by women and people aged less than 65. Such improvement was less frequent among those who were still highly exposed to the pandemic's media coverage after the end of the confinement. Conclusion: The possibility of recovering a good sleep largely depends on the type of sleep disorder. The decrease in sleep problems occurred mainly among people with mild sleep problems during the confinement. Further research is needed to assess the long-term effects of the Covid-19 pandemic and its confinement period on sleep quality in the general population

Community intervention for child tuberculosis active contact investigation and management : study protocol for a parallel cluster randomized controlled trial

Background: There are major gaps in the management of pediatric tuberculosis (TB) contact investigation for rapid identification of active tuberculosis and initiation of preventive therapy. This study aims to evaluate the impact of a community-based intervention as compared to facility-based model for the management of children in contact with bacteriologically confirmed pulmonary TB adults in low-resource high-burden settings. Methods/design: This multicenter parallel open-label cluster randomized controlled trial is composed of three phases: I, baseline phase in which retrospective data are collected, quality of data recording in facility registers is checked, and expected acceptability and feasibility of the intervention is assessed; II, intervention phase with enrolment of index cases and contact cases in either facility- or community-based models; and III, explanatory phase including endpoint data analysis, cost-effectiveness analysis, and post-intervention acceptability assessment by healthcare providers and beneficiaries. The study uses both quantitative and qualitative analysis methods. The community-based intervention includes identification and screening of all household contacts, referral of contacts with TB-suggestive symptoms to the facility for investigation, and household initiation of preventive therapy with follow-up of eligible child contacts by community healthcare workers, i.e., all young (< 5 years) child contacts or older (5-14 years) child contacts living with HIV, and with no evidence of TB disease. Twenty clusters representing TB diagnostic and treatment facilities with their catchment areas are randomized in a 1:1 ratio to either the community-based intervention arm or the facility-based standard of care arm in Cameroon and Uganda. Randomization was stratified by country and constrained on the number of index cases per cluster. The primary endpoint is the proportion of eligible child contacts who initiate and complete the preventive therapy. The sample size is of 1500 child contacts to identify a 10% difference between the arms with the assumption that 60% of children will complete the preventive therapy in the standard of care arm. Discussion: This study will provide evidence of the impact of a community-based intervention on household child contact screening and management of TB preventive therapy in order to improve care and prevention of childhood TB in low-resource high-burden settings

Rhizobia use a pathogenic-like effector to hijack leguminous nodulation signalling

Legume plants form a root-nodule symbiosis with rhizobia. This symbiosis establishment generally relies on rhizobium-produced Nod factors (NFs) and their perception by leguminous receptors (NFRs) that trigger nodulation. However, certain rhizobia hijack leguminous nodulation signalling via their type III secretion system, which functions in pathogenic bacteria to deliver effector proteins into host cells. Here, we report that rhizobia use pathogenic-like effectors to hijack legume nodulation signalling. The rhizobial effector Bel2-5 resembles the XopD effector of the plant pathogen Xanthomonas campestris and could induce nitrogen-fixing nodules on soybean nfr mutant. The soybean root transcriptome revealed that Bel2-5 induces expression of cytokinin-related genes, which are important for nodule organogenesis and represses ethylene- and defense-related genes that are deleterious to nodulation. Remarkably, Bel2-5 introduction into a strain unable to nodulate soybean mutant affected in NF perception conferred nodulation ability. Our findings show that rhizobia employ and have customized pathogenic effectors to promote leguminous nodulation signalling

Overview of the French operational network for in situ observation of PM chemical composition and sources in urban environments (CARA Program)

The CARA program has been running since 2008 by the French reference laboratory for air quality monitoring (LCSQA) and the regional monitoring networks, to gain better knowledge-at a national level-on particulate matter (PM) chemistry and its diverse origins in urban environments. It results in strong collaborations with international-level academic partners for state-of-the-art, straightforward, and robust results and methodologies within operational air quality stakeholders (and subsequently, decision makers). Here, we illustrate some of the main outputs obtained over the last decade, thanks to this program, regarding methodological aspects (both in terms of measurement techniques and data treatment procedures) as well as acquired knowledge on the predominant PM sources. Offline and online methods are used following well-suited quality assurance and quality control procedures, notably including inter-laboratory comparison exercises. Source apportionment studies are conducted using various receptor modeling approaches. Overall, the results presented herewith underline the major influences of residential wood burning (during the cold period) and road transport emissions (exhaust and non-exhaust ones, all throughout the year), as well as substantial contributions of mineral dust and primary biogenic particles (mostly during the warm period). Long-range transport phenomena, e.g., advection of secondary inorganic aerosols from the European continental sector and of Saharan dust into the French West Indies, are also discussed in this paper. Finally, we briefly address the use of stable isotope measurements (delta N-15) and of various organic molecular markers for a better understanding of the origins of ammonium and of the different organic aerosol fractions, respectively