Extraction of High-Quality RNA from S. aureus Internalized by Endothelial Cells

Staphylococcus aureus evades antibiotic therapy and antimicrobial defenses by entering human host cells. Bacterial transcriptomic analysis represents an invaluable tool to unravel the complex interplay between host and pathogen. Therefore, the extraction of high-quality RNA from intracellular S. aureus lays the foundation to acquire meaningful gene expression data. In this study, we present a novel and straightforward strategy to isolate RNA from internalized S. aureus after 90 min, 24 h, and 48 h postinfection. Real-time PCR data were obtained for the target genes agrA and fnba , which play major roles during infection. The commonly used reference genes gyrB , aroE , tmRNA , gmk , and hu were analyzed under different conditions: bacteria from culture (condition I), intracellular bacteria (condition II), and across both conditions I and II. The most stable reference genes were used for the normalization of agrA and fnbA . Delta C q (quantification cycle) values had a relatively low variability and thus demonstrated the high quality of the extracted RNA from intracellular S. aureus during the early phase of infection. The established protocol allows the extraction and purification of intracellular staphylococcal RNA while minimizing the amount of host RNA in the sample. This approach can leverage reproducible gene expression data to study host–pathogen interactions

Ecological equivalence: a realistic assumption for niche theory as a testable alternative to neutral theory

Hubbell's 2001 neutral theory unifies biodiversity and biogeography by modelling steady-state distributions of species richness and abundances across spatio-temporal scales. Accurate predictions have issued from its core premise that all species have identical vital rates. Yet no ecologist believes that species are identical in reality. Here I explain this paradox in terms of the ecological equivalence that species must achieve at their coexistence equilibrium, defined by zero net fitness for all regardless of intrinsic differences between them. I show that the distinction of realised from intrinsic vital rates is crucial to evaluating community resilience. An analysis of competitive interactions reveals how zero-sum patterns of abundance emerge for species with contrasting life-history traits as for identical species. I develop a stochastic model to simulate community assembly from a random drift of invasions sustaining the dynamics of recruitment following deaths and extinctions. Species are allocated identical intrinsic vital rates for neutral dynamics, or random intrinsic vital rates and competitive abilities for niche dynamics either on a continuous scale or between dominant-fugitive extremes. Resulting communities have steady-state distributions of the same type for more or less extremely differentiated species as for identical species. All produce negatively skewed log-normal distributions of species abundance, zero-sum relationships of total abundance to area, and Arrhenius relationships of species to area. Intrinsically identical species nevertheless support fewer total individuals, because their densities impact as strongly on each other as on themselves. Truly neutral communities have measurably lower abundance/area and higher species/abundance ratios. Neutral scenarios can be parameterized as null hypotheses for testing competitive release, which is a sure signal of niche dynamics. Ignoring the true strength of interactions between and within species risks a substantial misrepresentation of community resilience to habitat los

Predicting dispersal of auto-gyrating fruit in tropical trees : a case study from the Dipterocarpaceae

Acknowledgments We thank the Sabah Forestry Department for access to SFR and the Rainforest Discovery Center for use of the canopy tower. JRS is funded by the Swiss National Science Foundation (SNF) grant number PDFMP3_132479/1. We are grateful for the comments of two anonymous reviewers which greatly improved the manuscript.Peer reviewedPublisher PD

Time-to-effect guided pulmonary vein isolation utilizing the third-generation versus second generation cryoballoon: One year clinical success

Background: The second-generation cryoballoon (CB2) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging and reproducible clinical outcome data. The latest- -generation cryoballoon (CB3) incorporates a 40% shorter distal tip, thus allowing for an increased rate of PVI real-time signal recording and facilitating individualized ablation strategies taking the time-to- -effect (TTE) into account. However, whether this characteristic translates into favorable clinical success has not been evaluated yet. Herein was investigated 1-year clinical success after CB3 in comparison to CB2 based-PVI. Methods: One hundred and ten consecutive patients with paroxysmal or short-standing persistent atrial fibrillation (AF) underwent CB2 (n = 55 patients) -or CB3 (n = 55 patients) -based PVI. The freeze-cycle duration was set to TTE + 120 s if TTE could be recorded, otherwise a fixed freeze-cycle duration of 180 s was applied. Results: A total of 217/218 (99%, CB3) and 217/217 (100%, CB2) pulmonary veins (PV) were successfully isolated. The real-time PVI visualization rate was 69.2% (CB3) and 54.8% (CB2; p = 0.0392). The mean freeze-cycle duration was 194 ± 77 s (CB3) and 206 ± 85 s (CB2; p = 0.132), respectively. During a median follow-up of 409 days (interquartile range [IQR] 378–421, CB3) and 432 days (IQR 394–455, CB2) 73.6% (CB3) and 73.1% of patients (CB2) remained in stable sinus rhythm after a single procedure (p = 0.806). Conclusions: A higher rate of real-time electrical PV recordings was seen using the CB3 as compared to CB2. There was no difference in 1-year clinical follow-up

Neutrality and the Response of Rare Species to Environmental Variance

Neutral models and differential responses of species to environmental heterogeneity offer complementary explanations of species abundance distribution and dynamics. Under what circumstances one model prevails over the other is still a matter of debate. We show that the decay of similarity over time in rocky seashore assemblages of algae and invertebrates sampled over a period of 16 years was consistent with the predictions of a stochastic model of ecological drift at time scales larger than 2 years, but not at time scales between 3 and 24 months when similarity was quantified with an index that reflected changes in abundance of rare species. A field experiment was performed to examine whether assemblages responded neutrally or non-neutrally to changes in temporal variance of disturbance. The experimental results did not reject neutrality, but identified a positive effect of intermediate levels of environmental heterogeneity on the abundance of rare species. This effect translated into a marked decrease in the characteristic time scale of species turnover, highlighting the role of rare species in driving assemblage dynamics in fluctuating environments

Clinical outcomes of cryoballoon ablation for pulmonary vein isolation: Impact of intraprocedural heart rhythm

Background: The current study sought to assess the impact of the intraprocedural heart rhythm (sinus rhythm [SR] vs. atrial fibrillation [AF]) on acute procedural characteristics, durability of pulmonary vein isolation (PVI) and long-term clinical outcomes of cryoballoon (CB) ablation. Methods: A total of 195 patients with symptomatic paroxysmal (n = 136) or persistent AF (n = 59) underwent CB-based PVI. Ablation procedures were either performed in SR (SR group; n = 147) or during AF (AF group; n = 48). Persistent AF was more frequent in the AF group than in the SR group (62% vs. 20%). All other patient baseline characteristics did not differ between the two groups. Results: The nadir temperature during the CB applications was significantly lower in the AF group than in patients in the SR group (–49 [interquartile range, –44; –54]°C vs. –47 [-42; –52]°C, p = 0.002). Median procedure and fluoroscopy times as well as the rate of real-time recordings were not different between the two groups. Repeat ablation for the treatment of atrial arrhythmia recurrence was performed in 60 patients (SR: 44 [30%] patients; AF: 16 [33%] patients), with a trend towards a lower rate of PV reconnections in the AF group (p = 0.07). There was no difference in 3-year arrhythmia-free survival (p = 0.8). Conclusions: Cryoballoon-based PVI during AF results in lower nadir balloon temperatures and a trend towards a higher durability of PVI as compared to procedures performed in SR. The rate of real-time PVI recordings was not affected by the intraprocedural heart rhythm

Microbial technology with major potentials for the urgent environmental needs of the next decades

Several needs in the context of the water-energy-food nexus will become more prominent in the next decades. It is crucial to delineate these challenges and to find opportunities for innovative microbial technologies in the framework of sustainability and climate change. Here, we focus on four key issues, that is the imbalance in the nitrogen cycle, the diffuse emission of methane, the necessity for carbon capture and the deterioration of freshwater reserves. We suggest a set of microbial technologies to deal with each of these issues, such as (i) the production of microbial protein as food and feed, (ii) the control of methanogenic archaea and better use of methanotrophic consortia, (iii) the avoidance of nitrification and (iv) the upgrading of CO2 to microbial bioproducts. The central message is that instead of using crude methods to exploit microorganisms for degradations, the potentials of the microbiomes should be used to create processes and products that fit the demands of the cyclic market economy