Fluctuating asymmetry and environmental stress : understanding the role of trait history

While fluctuating asymmetry (FA; small, random deviations from perfect symmetry in bilaterally symmetrical traits) is widely regarded as a proxy for environmental and genetic stress effects, empirical associations between FA and stress are often weak or heterogeneous among traits. A conceptually important source of heterogeneity in relationships with FA is variation in the selection history of the trait(s) under study, i.e. traits that experienced a (recent) history of directional change are predicted to be developmentally less stable, potentially through the loss of canalizing modifiers. Here we applied X-ray photography on museum specimens and live captures to test to what extent the magnitude of FA and FA-stress relationships covary with directional shifts in traits related to the flight apparatus of four East-African rainforest birds that underwent recent shifts in habitat quality and landscape connectivity. Both the magnitude and direction of phenotypic change varied among species, with some traits increasing in size while others decreased or maintained their original size. In three of the four species, traits that underwent larger directional changes were less strongly buffered against random perturbations during their development, and traits that increased in size over time developed more asymmetrically than those that decreased. As we believe that spurious relationships due to biased comparisons of historic (museum specimens) and current (field captures) samples can be ruled out, these results support the largely untested hypothesis that directional shifts may increase the sensitivity of developing traits to random perturbations of environmental or genetic origin

FabR regulates Salmonella biofilm formation via its direct target FabB

Background: Biofilm formation is an important survival strategy of Salmonella in all environments. By mutant screening, we showed a knock-out mutant of fabR, encoding a repressor of unsaturated fatty acid biosynthesis (UFA), to have impaired biofilm formation. In order to unravel how this regulator impinges on Salmonella biofilm formation, we aimed at elucidating the S. Typhimurium FabR regulon. Hereto, we applied a combinatorial high-throughput approach, combining ChIP-chip with transcriptomics. Results: All the previously identified E. coli FabR transcriptional target genes (fabA, fabB and yqfA) were shown to be direct S. Typhimurium FabR targets as well. As we found a fabB overexpressing strain to partly mimic the biofilm defect of the fabR mutant, the effect of FabR on biofilms can be attributed at least partly to FabB, which plays a key role in UFA biosynthesis. Additionally, ChIP-chip identified a number of novel direct FabR targets (the intergenic regions between hpaR/hpaG and ddg/ydfZ) and yet putative direct targets (i.a. genes involved in tRNA metabolism, ribosome synthesis and translation). Next to UFA biosynthesis, a number of these direct targets and other indirect targets identified by transcriptomics (e.g. ribosomal genes, ompA, ompC, ompX, osmB, osmC, sseI), could possibly contribute to the effect of FabR on biofilm formation. Conclusion: Overall, our results point at the importance of FabR and UFA biosynthesis in Salmonella biofilm formation and their role as potential targets for biofilm inhibitory strategies

In-situ monitoring of RO membranes using electrical impedance spectroscopy: Threshold fluxes and fouling

Electrical impedance spectroscopy (EIS) was employed to monitor RO membranes in-situ during crossflow filtration using a membrane module fitted with suitable electrodes. EIS spectra can be analyzed in terms of layers and processes that are associated with different electrical time constants. One such layer identified in the spectra is the AC diffusion polarization layer that forms at the surface of the membrane within the concentration polarization layer. The conductance, (GDP) of this layer provides an indication of the nature of the material accumulating very close to the surface. When the feed water contained inorganic foulants such as silica, the value of GDP gradually deceased as the silica (a poorly conducting material) accumulated on the surface. However, once a more integrated cake forms, the value of GDP rises as the decrease in the mass transport coefficient due to the cake, leads to an increase in the salt concentration in this region; the so called cake enhanced concentration polarization (CECP) effect. The inflection point of GDP vs time was itself dependent on the value of the flux (decreasing with increases in flux) and crossflow velocity (increasing with increasing crossflow). This mimics the variation of the “critical” flux observed in porous membranes such as MF. It would thus appear that the inflection point for GDP corresponds to a threshold phenomenon where accumulation changes to cake formation and that it is a relatively well defined phenomenon, at least under controlled experimental conditions. This threshold flux could also be discerned in flux-step experiments where the differential rate changes in TMP (transmembrane pressure) vs time displayed a similar inflection. The threshold flux so determined was indeed very close to that determined from the GDP profiles. The concept of a “Threshold” flux, its relation to cake formation and its detection using EIS could be used for in-situ monitoring of RO membranes to optimize performance of plants. That could either be achieved using a “Canary” crossflow membrane module (fitted with suitable electrodes) connected in a side stream of a RO train or by suitable modification of the spiral wound modules themselves. Field trials to evaluate the economics of this have begun

Electrochemical impedance spectroscopy of enhanced layered nanocomposite ion exchange membranes

This work presents the enhancement of Cl−/SO42− mono-selectivity of layered nanocomposite anion exchange membranes (AEMs) and the mechanism that supports this improvement. These nanocomposite membranes are based on commercial polyethylene AEMs and a nanocomposite negative thin layer composed of sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) and a functionalized nanomaterial, Fe2O3−SO42− nanoparticles or oxidized multi-walled carbon nanotubes CNTs-COO−. The mechanism for monovalent selectivity was confirmed by characterizing nanocomposite membranes and commercial heterogeneous ion exchange membranes (IEMs) using ζ-potential and electrochemical impedance spectroscopy (EIS). ζ-potential measurements confirmed the modification of the charge of surface of the membrane after being coated with the nanocomposite layer. EIS measurements showed a totally different electrical performance between layered nanocomposite membranes and commercial IEMs. The electrical data from EIS was fitted to a Maxwell-Wagner model providing an equivalent electric circuit (EEC) for each membrane. The observed differences in ECC were related to the structural differences of the membranes. A physical explanation of the phenomena that caused these differences is provided. The influence of ion concentration on EIS measurements was also studied. To the best of our knowledge, this is the first time that an ECC related to the structure of advanced layered IEMs is proposed.Financial support from MICINN under project CTM2014-57833-R and CTQ2013-48280-C3-1-R-D is gratefully acknowledged. The authors thank the Ministry of Economy, Industry and Competitiveness for the FPI grant BES-2012-053461 and the scholarships EEBB-I-15-10268 and EEBB-I-16-11614. In addition, this research was partially supported by the U.S. National Science Foundation CBET-1235166

Environmentally and behaviourally mediated co-occurrence of functional traits in bird communities of tropical forest fragments

Two major theories of community assembly - based on the assumption of limiting similarity' or 'habitat filtering', respectively - predict contrasting patterns in the spatial arrangement of functional traits. Previous analyses have made progress in testing these predictions and identifying underlying processes, but have also pointed to theoretical as well as methodological shortcomings. Here we applied a recently developed methodology for spatially explicit analysis of phylogenetic meta-community structure to study the pattern of co-occurrence of functional traits in Afrotropical and Neotropical bird species inhabiting forest fragments. Focusing separately on locomotory, dietary, and dispersal traits, we tested whether environmental filtering causes spatial clustering, or competition leads to spatial segregation as predicted by limiting similarity theory. We detected significant segregation of species co-occurrences in African fragments, but not in the Neotropical ones. Interspecific competition had a higher impact on trait co-occurrence than filter effects, yet no single functional trait was able to explain the observed degree of spatial segregation among species. Despite high regional variability spanning from spatial segregation to aggregation, we found a consistent tendency for a clustered spatial patterning of functional traits among communities in fragmented landscapes, particularly in non-territorial species. Overall, we show that behavioural effects, such as territoriality, and environmental effects, such as the area of forest remnants or properties of the landscape matrix in which they are embedded, can strongly affect the pattern of trait co-occurrence. Our findings suggest that trait-based analyses of community structure should include behavioural and environmental covariates, and we here provide an appropriate method for linking functional traits, species ecology and environmental conditions to clarify the drivers underlying spatial patterns of species co-occurrence

Energy and Protein Intake After Return Home in Colorectal Surgery Patients With an Enhanced Recovery Program: A Prospective Observational Study.

[en] BACKGROUND: In patients scheduled for colorectal surgery with an enhanced recovery program (ERP), feeding after returning home has been insufficiently investigated. The aim of this study was to measure energy and protein intake during the first month at home. METHODS: Seventy adult patients scheduled for colorectal surgery with ERP were included. Calorie and protein intakes were calculated, and body weight was measured preoperatively and 3, 7, 15, and 30 days after discharge home. Data are mean ± SD or median (interquartile range). RESULTS: Patient characteristics were age 60.0 ± 15.0 years, BMI = 25.9 ± 5.5 kg/m2 , and colon/rectum of 56/14. The duration of hospitalization was 3 (2-5) days. Calorie and protein intakes (21.9 [17.7-28.6] kilocalorie per kilogram of ideal body weight [kcal/kg IBW] and 0.81 [0.61-1.14] g/kg IBW) were significantly reduced (P < .01) by 15% on day 3, compared with preoperative values, and then increased gradually to reach preoperative values after 1 month. Almost 50% of the patients failed to reach the calorie intake target of 25 kcal/kg IBW, and almost no patient reached the protein intake target of 1.5 g/kg IBW 30 days after discharge home. Weight loss after 30 days at home remained at -1.8 ± 2.7 kg. CONCLUSIONS: Colorectal surgery, even in an ERP, is associated with energy and protein intake below the targets recommended for the rehabilitation phase and results in weight loss. Whether nutrition counseling and prolonged administration of protein-enriched oral supplements could accelerate weight gain needs to be explored

Drug repurposing: phosphate prodrugs of anticancer and antiviral FDA-approved nucleosides as novel antimicrobials

Objectives Following a drug repurposing approach, we aimed to investigate and compare the antibacterial and antibiofilm activities of different classes of phosphate prodrugs (HepDirect, cycloSal, SATE and mix SATE) of antiviral and anticancer FDA-approved nucleoside drugs [zidovudine (AZT), floxouridine (FUDR) and gemcitabine (GEM)] against a variety of pathogenic Gram-positive and -negative bacteria. Methods Ten prodrugs were synthesized and screened for antibacterial activity against seven Gram-negative and two Gram-positive isolates fully susceptible to traditional antibiotics, alongside six Gram-negative and five Gram-positive isolates with resistance mechanisms. Their ability to prevent and eradicate biofilms of different bacterial pathogens in relation to planktonic growth inhibition was also evaluated, together with their effect on proliferation, viability and apoptosis of different eukaryotic cells. Results The prodrugs showed decreased antibacterial activity compared with the parent nucleosides. cycloSal-GEM-monophosphate (MP) prodrugs 20a and 20b were the most active agents against Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) and retained their activity against antibiotic-resistant isolates. cycloSal-FUDR-MP 21a partially retained good activity against the Gram-positive bacteria E. faecalis, Enterococcus faecium and S. aureus. Most of the prodrugs tested displayed very potent preventive antibiofilm specific activity, but not curative. In terms of cytotoxicity, AZT prodrugs did not affect apoptosis or cell viability at the highest concentration tested, and only weak effects on apoptosis and/or cell viability were observed for GEM and FUDR prodrugs. Conclusions Among the different prodrug approaches, the cycloSal prodrugs appeared the most effective. In particular, cycloSal (17a) and mix SATE (26) AZT prodrugs combine the lowest cytotoxicity with high and broad antibacterial and antibiofilm activity against Gram-negative bacteria

Real-world insights into risk of developing cardiovascular disease following GnRH agonists versus antagonists for prostate cancer: a methodological protocol to a study using five European databases

International audienc

Large-scale real-world data on a multidisciplinary approach to spinal cord stimulation for persistent spinal pain syndromes: first evaluation of the Neuro-Pain® nationwide screening and follow-up interactive register

IntroductionSpinal cord stimulation is a common treatment option for neuropathic pain conditions. Despite its extensive use and multiple technological evolutions, long term efficacy of spinal cord stimulation is debated. Most studies on spinal cord stimulation include a rather limited number of patients and/or follow-ups over a limited period. Therefore, there is an urgent need for real-world, long-term data.MethodsIn 2018, the Belgian government initiated a nationwide secure platform for the follow-up of all new and existing spinal cord stimulation therapies. This is a unique approach used worldwide. Four years after the start of centralized recording, the first global extraction of data was performed.ResultsHerein, we present the findings, detailing the different steps in the centralized procedure, as well as the observed patient and treatment characteristics. Furthermore, we identified dropouts during the screening process, the reasons behind discontinuation, and the evolution of key indicators during the trial period. In addition, we obtained the first insights into the evolution of the clinical impact of permanent implants on the overall functioning and quality of life of patients in the long-term.DiscussionAlthough these findings are the results of the first data extraction, some interesting conclusions can be drawn. The long-term outcomes of neuromodulation are complex and subject to many variables. Future data extraction will allow us to identify these confounding factors and the early predictors of success. In addition, we will propose further optimization of the current process