10/06/2024


Grazing by herbivorous protists contributes to structuring plankton communities through its effect on the growth, biomass, and competitiveness of prey organisms and also impacts the transfer of primary production towards higher trophic levels. Previous evidence shows that heterotrophic processes (grazing rates, g) are more sensitive to temperature than autotrophic ones (phytoplankton growth rates, μ) and also that small cells tend to be more heavily predated than larger ones; however, it remains unresolved how the interplay between changes in temperature and cell size modulates grazing pressure (i.e., gμ ratio). We addressed this problem by conducting an experiment with four phytoplankton populations, from pico- to microphytoplankton, over a 12 °C gradient and in the presence/absence of a generalist herbivorous protist, Oxyrrhis marina. We found that highest g rates coincided with highest μ rates, which corresponded to intermediate cell sizes. There were no significant differences in either μ or g between the smallest and largest cell sizes considered. The gμ ratio was largely independent of cell size and CN ratios, and its thermal dependence was low although species-specific differences were large. We suggest that the similar gμ found could be the consequence that the energetic demand imposed by rising temperatures would be a more important issue than the mechanical constriction to ingestion derived from prey cell size. Despite the difficulty of quantifying μ and g in natural planktonic communities, we suggest that the gμ ratio is a key response variable to evaluate thermal sensitivity of food webs because it gives a more integrative view of trophic functioning than both rates separately.Natural ponds in the Brazilian Cerrado harbor high biodiversity but are still poorly studied, especially their microbial assemblage. The characterization of the microbial community in aquatic environments is fundamental for understanding its functioning, particularly under the increasing pressure posed by land conversion and climate change. Here, we aim to characterize the structure (abundance, richness, and diversity) and composition of the Bacteria and Archaea in the sediment of two natural ponds belonging to different basins that primarily differ in size and depth in the Cerrado. Sediment samples were collected in the dry and rainy seasons and the transition periods between both. The structure and composition of Bacteria and Archaea were assessed by 16S rRNA gene pyrosequencing. We identified 45 bacterial and four archaeal groups. Proteobacteria and Acidobacteria dominated the bacterial community, while Euryarchaeota and Thaumarchaeota dominated the archaeal community. Seasonal fluctuations in the relative abundance of microbial taxa were observed, but pond characteristics were more determinant to community composition differences. Microbial communities are highly diverse, and local variability could partially explain the microbial structure's main differences. Functional predictions based in 16S rRNA gene accessed with Tax4Fun indicated an enriched abundance of predicted methane metabolism in the deeper pond, where higher abundance of methanogenic archaea Methanocella, Methanosaeta, and Methanomicrobiaceae was detected. Our dataset encompasses the more comprehensive survey of prokaryotic microbes in Cerrado's aquatic environments. Here, we present basic and essential information about composition and diversity, for initial insights into the ecology of Bacteria and Archaea in these environments.Misophonia is a condition of abnormal emotional responses to specific auditory stimuli. There is limited information available on the prevalence of this condition. https://www.selleckchem.com/products/jib-04.html This study aimed to estimate the prevalence of misophonia in an undergraduate medical student population at the University of Nottingham. A secondary aim of this study was to assess the psychometric validity of the Amsterdam Misophonia Scale (A-Miso-S) questionnaire tool in this population. The A-Miso-S was administered online to medical students at the University of Nottingham. To assess the validity of the A-Miso-S, a factor analysis was conducted. To determine prevalence and severity the results of the questionnaire were quantitatively analysed using SPSS. Actor analysis was conducted. Free text responses to one questionnaire item were analysed using a thematic approach. Responses were obtained from 336 individuals. Clinically significant misophonic symptoms appear to be common, effecting 49.1% of the sample population. This is statistically significantly higher prevalence than previous studies have found (p  less then  0.00001). Using the classification of the A-Miso-S, mild symptoms were seen in 37%, moderate in 12%, severe in 0.3% of participants. No extreme cases were seen. The A-Miso-S was found to be a uni-factorial tool, with good internal consistency. This study has provided new information on misophonia and validity of the A-Miso-S questionnaire in a sample population of UK undergraduate medical students. The results indicate that misophonia is a phenomenon that a significant proportion of medical students experience though only a small subset experience it severely.Detection of lead(II) (Pb2+) ions in water is important for the protection of human health and environment. The growing demand for onsite detection still faces challenges for sensitive and easy-to-use methods. In this work, a novel surface plasmon resonance (SPR) biosensor based on GR-5 DNAzyme and gold nanoparticles (AuNPs) was developed. Thiolated DNAzyme was immobilized on the gold surface of the sensor chip followed by anchoring the substrate-functionalized AuNPs through the DNAzyme-substrate hybridization. The coupling between the localized surface plasmon (LSP) of AuNPs and the surface plasmon polaritons (SPP) on the gold sensor surface was used to improve the sensitivity. The substrate cleavage in the presence of Pb2+ ions was catalyzed by DNAzyme, leading to the removal of AuNPs and the diminished LSP-SPP coupling. The optimal detection limit was 80 pM for the sensor fabricated with 1 μM DNAzyme, corresponding to two or three orders of magnitude lower than the toxicity levels of Pb2+ in drinking water defined by WHO and USEPA.