Tidal Dwarf Galaxies at Intermediate Redshifts

We present the first attempt at measuring the production rate of tidal dwarf galaxies (TDGs) and estimating their contribution to the overall dwarf population. Using HST/ACS deep imaging data from GOODS and GEMS surveys in conjunction with photometric redshifts from COMBO-17 survey, we performed a morphological analysis for a sample of merging/interacting galaxies in the Extended Chandra Deep Field South and identified tidal dwarf candidates in the rest-frame optical bands. We estimated a production rate about 1.4 {\times} 10^{-5} per Gyr per comoving volume for long-lived TDGs with stellar mass 3 {\times} 10^{8-9} solar mass at 0.5<z<1.1. Together with galaxy merger rates and TDG survival rate from the literature, our results suggest that only a marginal fraction (less than 10%) of dwarf galaxies in the local universe could be tidally-originated. TDGs in our sample are on average bluer than their host galaxies in the optical. Stellar population modelling of optical to near-infrared spectral energy distributions (SEDs) for two TDGs favors a burst component with age 400/200 Myr and stellar mass 40%/26% of the total, indicating that a young stellar population newly formed in TDGs. This is consistent with the episodic star formation histories found for nearby TDGs.Comment: 9 pages, 5 figures, Accepted for publication in Astrophysics & Space Scienc

Pathogen-induced activation of disease-suppressive functions in the endophytic root microbiome

Microorganisms living inside plants can promote plant growth and health, but their genomic and functional diversity remain largely elusive. Here, metagenomics and network inference show that fungal infection of plant roots enriched for Chitinophagaceae and Flavobacteriaceae in the root endosphere and for chitinase genes and various unknown biosynthetic gene clusters encoding the production of nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). After strain-level genome reconstruction, a consortium of Chitinophaga and Flavobacterium was designed that consistently suppressed fungal root disease. Site-directed mutagenesis then revealed that a previously unidentified NRPS-PKS gene cluster from Flavobacterium was essential for disease suppression by the endophytic consortium. Our results highlight that endophytic root microbiomes harbor a wealth of as yet unknown functional traits that, in concert, can protect the plant inside out.Microbial Biotechnolog

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Land-use system shapes soil bacterial communities in Southeastern Amazon region

The expansion of the agriculture has become the main agent of disturbance in the Amazon region, and such alteration has consequences on soil microbial communities, which represent the majority of biodiversity in terrestrial ecosystems. In this study we assessed the effects of land-use changes on physicochemical soil properties and, consequently, on the bacterial communities in soils from Southeastern Amazon, Brazil. Soil samples were collected in four distinct land-use systems, i.e. native forest, deforested area, agricultural and pasture fields. The soil bacterial community abundance, structure and composition were addressed using qPCR, one molecular marker (T-RFLP) and high-throughput sequencing of the bacterial 16S rRNA gene, respectively. Obtained data were analyzed using multivariate techniques. We found that the type of land-use had a primary effect on the soil bacterial communities, whereas parameters such as pH, C, N, NO3− and K content significantly correlated to overall community structures. We observed that the abundance and taxonomic diversity of the bacterial 16S rRNA changed to a higher extent according to the land-use system, but they also showed significant temporal turnover within sites. From the total 27 bacterial phyla identified, 12 presented clearly differential distribution across the four land-use systems. Comparison among all sites revealed Acidobacteria and Chlamydiae to be higher abundant in forest soil, Actinobacteria in deforested site, Nitrospira and Deinococcus-Thermus in agriculture and Firmicutes in pasture. When data of specific phyla were correlated to specific soil properties, we demonstrated that parameters such as Al saturation index, Al, base saturation index, Mg and Ca presented correlation with the most number of bacterial groups detected. Thus, we suggest that several soil parameters besides pH should be taken into account when assessing the impacts of land-use change on the microbial communities