Distinct Temporal Succession of Bacterial Communities in Early Marine Biofilms in a Portuguese Atlantic Port

Marine biofilms are known to influence the corrosion of metal surfaces in the marine environment. Despite some recent research, the succession of bacterial communities colonizing artificial surfaces remains uncharacterized in some temporal settings. More specifically, it is not fully known if bacterial colonizers of artificial surfaces are similar or distinct in the different seasons of the year. In particular the study of early biofilms, in which the bacterial cells communities first adhere to artificial surfaces, are crucial for the development of the subsequent biofilm communities. In this work, we used amplicon-based NGS (next-generation sequencing) and universal 16S rRNA bacterial primers to characterize the early biofilm bacterial communities growing on 316 L stainless steel surfaces in a Northern Portugal port. Sampling spanned 30-day periods in two distinct seasons (spring and winter). Biofilm communities growing in steel surfaces covered with an anti-corrosion paint and planktonic communities from the same location were also characterized. Our results demonstrated that distinct temporal patterns were observed in the sampled seasons. Specifically, a significantly higher abundance of Gammaproteobacteria and Mollicutes was found on the first days of biofilm growth in spring (day 1 to day 4) and a higher abundance of Alphaproteobacteria during the same days of biofilm growth in winter. In the last sampled day (day 30), the spring biofilms significantly shifted toward a dominance of photoautotrophic groups (mostly diatoms) and were also colonized by some macrofouling communities, something not observed during the winter sampling. Our results revealed that bacterial composition in the biofilms was particularly affected by the sampled day of the specific season, more so than the overall effect of the season or overall sampling day of both seasons. Additionally, the application of a non-fouling-release anti-corrosion paint in the steel plates resulted in a significantly lower diversity compared with plates without paint, but this was only observed during spring. We suggest that temporal succession of marine biofilm communities should be taken in consideration for future antifouling/anti-biofilm applications.JTA was supported by the FCT grant SFRH/BD/99003/2013. This research was also supported by the projects NOVELMAR – Novel marine products with biotechnological applications (INNOVMAR NORTE-01-0145-FEDER-000035) and UID/Multi/04423/2019, as well as through grant IF/01358/2014 to PL, through national funds provided by the Portuguese Foundation for Science and Technology (FCT) and the European Regional Development Fund (ERDF), in the framework of the programme PT2020 and funding was provided by the project NASCEM PTDC/BTA-BTA/31422/2017 (POCI-01-0145-FEDER-031422), financed by the FCT, COMPETE2020 and PORTUGAL2020

Cyanobacterial allelochemicals but not cyanobacterial cells markedly reduce microbial community diversity

The freshwater cyanobacterium Phormidium sp. LEGE 05292 produces allelochemicals, including the cyclic depsipeptides portoamides, that influence the growth of heterotrophic bacteria, cyanobacteria, and eukaryotic algae. Using 16S rRNA gene amplicon metagenomics, we show here that, under laboratory conditions, the mixture of metabolites exuded by Phormidium sp. LEGE 05292 markedly reduces the diversity of a natural planktonic microbial community. Exposure of the same community to the portoamides alone resulted in a similar outcome. In both cases, after 16 days, alpha-diversity estimates for the allelochemical-exposed communities were less than half of those for the control communities. Photosynthetic organisms, but also different heterotrophic-bacteria taxa were found to be negatively impacted by the allelochemicals. Intriguingly, when Phormidium sp. LEGE 05292 was co-cultured with the microbial community, the latter remained stable and closer to non-exposed than to allelochemical-exposed communities. Overall, our observations indicate that although under optimal growth conditions Phormidium sp. LEGE 05292 is able to synthesize potent allelochemicals that severely impact different microorganisms, its allelopathic effect is not pronounced when in contact with a complex microbial community. Therefore, under ecologically relevant conditions, the allelopathic behavior of this cyanobacterium may be regulated by nutrient availability or by interactions with the surrounding microbiota. Copyright © 2017 Dias, Antunes, Ribeiro, Azevedo, Vasconcelos and Leão.Funding We acknowledge support from Fundação para a Ciência e a Tecnologia (FCT) through grant IF/01358/2014 to PL and through the project UID/Multi/04423/2013. This work was also supported by the Structured Program of R&D&I INNOVMAR (reference NORTE-01-0145-FEDER-000035, Research Line NOVELMAR), funded by the Northern Regional Operational Program (NORTE2020) through the European Regional Development Fund (ERDF)

Evaluation of turbulent dissipation rate retrievals from Doppler Cloud Radar

Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in particularly low- or high-turbulence regimes, but in general the radar-retrieved values correspond well with the in situ measurements. Root mean square differences are typically a factor of 4-6 relative to any given magnitude of dissipation rate. These differences are no larger than those found when comparing dissipation rates computed from tetheredballoon and meteorological tower-mounted sonic anemometer measurements made at spatial distances of a few hundred meters. Temporal lag analyses suggest that approximately half of the observed differences are due to spatial sampling considerations, such that the anticipated radar-based retrieval uncertainty is on the order of a factor of 2-3. Moreover, radar retrievals are clearly able to capture the vertical dissipation rate structure observed by the in situ sensors, while offering substantially more information on the time variability of turbulence profiles. Together these evaluations indicate that radar-based retrievals can, at a minimum, be used to determine the vertical structure of turbulence in Arctic stratocumulus clouds

Low-diffusion Xe-He gas mixtures for rare-event detection: electroluminescence yield

High pressure xenon Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification are being proposed for rare event detection such as directional dark matter, double electron capture and double beta decay detection. The discrimination of the rare event through the topological signature of primary ionisation trails is a major asset for this type of TPC when compared to single liquid or double-phase TPCs, limited mainly by the high electron diffusion in pure xenon. Helium admixtures with xenon can be an attractive solution to reduce the electron diffu- sion significantly, improving the discrimination efficiency of these optical TPCs. We have measured the electroluminescence (EL) yield of Xe–He mixtures, in the range of 0 to 30% He and demonstrated the small impact on the EL yield of the addition of helium to pure xenon. For a typical reduced electric field of 2.5 kV/cm/bar in the EL region, the EL yield is lowered by ∼ 2%, 3%, 6% and 10% for 10%, 15%, 20% and 30% of helium concentration, respectively. This decrease is less than what has been obtained from the most recent simulation framework in the literature. The impact of the addition of helium on EL statistical fluctuations is negligible, within the experimental uncertainties. The present results are an important benchmark for the simulation tools to be applied to future optical TPCs based on Xe-He mixtures. [Figure not available: see fulltext.]

Energy calibration of the NEXT-White detector with 1% resolution near Q ββ of 136Xe

Excellent energy resolution is one of the primary advantages of electroluminescent high-pressure xenon TPCs. These detectors are promising tools in searching for rare physics events, such as neutrinoless double-beta decay (ββ0ν), which require precise energy measurements. Using the NEXT-White detector, developed by the NEXT (Neutrino Experiment with a Xenon TPC) collaboration, we show for the first time that an energy resolution of 1% FWHM can be achieved at 2.6 MeV, establishing the present technology as the one with the best energy resolution of all xenon detectors for ββ0ν searches. [Figure not available: see fulltext.

Mudança de paradigma no ensino da Bioquímica na licenciatura em Ciências da Nutrição na Universidade do Porto

No primeiro ano da licenciatura em Ciências da Nutrição, na Faculdade de Ciências da Nutriçãoe Alimentação, da Universidade do Porto, existem duas Unidades Curriculares que introduzem aBioquímica aos estudantes [Química Orgânica e Bioquímica I (no 1º e 2º semestres,respetivamente)] e cujos programas e modalidades pedagógicas estão inter-relacionados,confrontando o estudante, progressivamente ao longo do ano letivo, com oportunidades deaprendizagem ativa.A divulgação de descobertas científicas e o envolvimento dos estudantes em projetos deinvestigação científica melhoram a aprendizagem e a retenção de conhecimentos, assim comooperacionalizam a sua aplicabilidade prática, ao mesmo tempo que desenvolvem um efeitopositivo no interesse pela investigação científica.Com o objetivo de melhorar não só a aquisição de conhecimentos, mas também a compreensão e aplicabilidade dos mesmos, assim como o desenvolvimento de competências e de raciocíniohipotético-dedutivo pelos estudantes, o ensino da Bioquímica "tradicional/clássico/base" foimodificado de modo a: 1) introduzir a discussão de artigos científicos relevantes (nas sessõesteóricas e/ou práticas); 2) possibilitar o contacto com a investigação científica feita pelosdocentes (nas sessões teóricas) e 3) possibilitar a realização de pequenos projetos deinvestigação científica (nas sessões práticas). Nestas 3 modalidades pedagógicas estãosubjacentes temas bioquímicos que integram o programa "clássico/base" das referidas UnidadesCurriculares. Adicionalmente, ao estudante são divulgados, nas 3 modalidades pedagógicasacima referidas, temas atuais da Bioquímica Nutricional ao mesmo tempo que contacta comtodas as fases da metodologia de aquisição de conhecimentos, de raciocínio e de investigaçãousadas na área da Nutrição

Immunophenotype of gastric tumors unveils a pleiotropic role of regulatory T cells in tumor development

Simple SummaryThe role of regulatory T cells (Tregs) in gastric cancer (GC) is still controversial and poorly understood. GC patients have increased numbers of Tregs in peripheral blood and among tumor infiltrating lymphocytes; however, their prognostic value depends on specific tumor features (e.g., tumor location and/or microsatellite instability status). We found that Tregs might induce membrane expression of IL2R alpha in intestinal-type GC cells, which associates with MAPK signaling pathway activation and spheroid growth. Moreover, Tregs accumulate at early steps of intestinal-type GCs progression, when tumors are starting to grow through the stomach wall, and do not present vascular and perineural invasion. Our findings suggest a novel non-immunosuppressive role of Treg cells in intestinal-type GC, which may unlock novel therapeutic immuno-oncology strategies for intestinal-type GC or other tumors with similar immune context.Gastric cancer (GC) patients display increased regulatory T cell (Tregs) numbers in peripheral blood and among tumor-infiltrating lymphocytes. Nevertheless, the role of Tregs in GC progression remains controversial. Here, we sought to explore the impact of Tregs in GCs with distinct histology, and whether Tregs can directly influence tumor cell behavior and GC development. We performed a comprehensive immunophenotyping of 82 human GC cases, through an integrated analysis of multispectral immunofluorescence detection of T cells markers and patient clinicopathological data. Moreover, we developed 3D in vitro co-cultures with Tregs and tumor cells that were followed by high-throughput and light-sheet imaging, and their biological features studied with conventional/imaging flow cytometry and Western blotting. We showed that Tregs located at the tumor nest were frequent in intestinal-type GCs but did not associate with increased levels of effector T cells. Our in vitro results suggested that Tregs preferentially infiltrated intestinal-type GC spheroids, induced the expression of IL2R alpha and activation of MAPK signaling pathway in tumor cells, and promoted spheroid growth. Accumulation of Tregs in intestinal-type GCs was increased at early stages of the stomach wall invasion and in the absence of vascular and perineural invasion. In this study, we proposed a non-immunosuppressive mechanism through which Tregs might directly modulate GC cells and thereby promote tumor growth. Our findings hold insightful implications for therapeutic strategies targeting intestinal-type GCs and other tumors with similar immune context.MTG4Molecular tumour pathology - and tumour genetic