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Antiviral activity against HSV-1 of triterpene saponins from Anagallis arvensis is related tothe fusion-inhibitory activity of desglucoanagalloside B
Get PDFThe identification of antiviral natural products as new lead structures has become a major task in medical science. Especially saponins have gained high interest for their antiviral activity. Antiviral effects of the saponin-containing plant Anagallis arvensis, widely used in traditional medicine, have been described, while mode of action or detailed phytochemical and functional investigations are still missing. A saponin enriched extract (AAS) from the aerial material of A. arvensis was characterized in detail by LC-HRMS, indicating the presence of a complex mixture of triterpene saponins and flavonoid glycosides. Plaque assays with Herpes simplex virus 1 (HSV-1) on Vero cells indicated strong inhibition of viral spread after infection of the host cells, resulting in reduced plaque size. The strongest effect was achieved by treating host cells post infection, which points towards an interference with the viral post-entry step. Using a specific HSV-1 fusion assay, AAS was shown to inhibit HSV-1 glycoprotein-mediated cell fusion at >2 μg/mL. Bioassay-guided fractionation of AAS yielded one active subfraction, which significantly reduced HSV-1 plaque size on Vero cells. The membrane-fusion inhibiting effect was correlated to the presence of desglucoanagalloside B 9. Interestingly, this compound was also detected in relevant amounts in herbal preparations from traditional medicine, which again could rationalize the use of A. arvensis as antiviral remedy in folk medicine. Relevant antiviral activity against SARS-CoV-2 was not detected
Cascades or salmons? Longitudinal upstream and downstream effects of political participation
Get PDFDigitally networked and new, unconventional activities allow citizens to participate politically in activities that are low in the effort and risks they bear. At the same time, low-effort types of participation are more loosely connected to democratic political systems, thereby challenging established modes of political decision-making. This can set in motion two competing dynamics: While some citizens move closer to the political system in their activities (upstream effects), others engage in political activities more distant from it (downstream effects). This study investigates non-electoral participation trajectories and tests intra-individual change in political participation types over time, exploring whether such dynamics depend on citizens’ exposure to political information. Utilizing a three-wave panel survey (n = 3490) and random intercept cross-lagged panel models with SEM, we find more evidence for downstream effects but detect overall diverse participation trajectories over time and a potentially crucial role of elections for non-electoral participation trajectories
Making observed and modeled Martian dust storm trajectories visible using a new automatic tracking algorithm [Software]
No full textThis software uses model output data from the Mars Planetary Climate Model (Mars PCM) to identify regions on Mars with enhanced atmospheric dust content and links these regions together in order to form coherent dust storm trajectories
A glovebox-integrated confocal microscope for quantum sensing in inert atmosphere
Get PDFConfocal microscopy is an invaluable tool for studying fluorescent materials and finds a wide application in biology and in quantum sensing. Usually, these experiments are performed under ambient conditions, but many materials are air sensitive (for example, black phosphorus) and degrade quickly under the strong laser irradiance. Here, we present a glovebox-integrated confocal microscope designed for nitrogen-vacancy (NV) center-based nano-scale sensing and NMR spectroscopy in an inert gas atmosphere. Using black phosphorus as a test material, we confirm that the glovebox maintains low oxygen levels and prevents material degradation during laser exposure. We demonstrate the setup’s capabilities through experiments that show NV center detection and spin manipulation under a black phosphorus flake. This custom-built system enables the study of air-sensitive materials and opens new perspectives for exploring surface chemistry in a controlled environment. Our work outlines both the strengths and the challenges of using a glovebox-integrated confocal microscope for quantum technology applications
Soil organic carbon stabilization is influenced by microbial diversity and temperature
Get PDFThe stabilization of soil organic carbon (SOC) is influenced by soil microbes and environmental factors, particularly temperature, which significantly affects SOC decomposition. This study investigates the effects of temperature (ambient: 25 °C; elevated: 27.5 °C) and soil microbial diversity (low, medium, and high) on the formation of stabilized SOC, focusing on mineral-associated organic carbon (MAOC) and water-stable aggregates, through a 75-day model soil incubation experiment. We measured water-stable aggregates, microbial respiration, and SOC in different fractions. Our results demonstrate that microbial diversity is crucial for SOC mineralization; low diversity resulted in 3.93–6.26% lower total carbon and 8.05–17.32% lower particulate organic carbon (POC) compared to medium and high diversity under the same temperature. While total MAOC was unaffected by temperature and microbial diversity, macroaggregate-occluded MAOC decreased by 8.78%, 38.36% and 9.40% under elevated temperature for low, medium and high diversity, respectively, likely driven by decreased macroaggregate formation. A negative correlation between macroaggregate-occluded POC and microbial respiration (r= -0.37, p < 0.05) suggested microbial decomposition of POC within macroaggregates contributed to respiration, with a portion of the decomposed POC potentially stabilized as microbial-derived MAOC. Notably, soils with medium microbial diversity exhibited the highest levels of both macroaggregate-occluded POC and MAOC at ambient temperature; however, elevated temperature disrupted this stabilization, reducing both POC retention and MAOC accumulation within macroaggregates. These findings underscore the temperature-sensitive interplay between microbial diversity and SOC stabilization, highlighting the need to disentangle microbial pathways governing C dynamics under climate change
Photo-regulated disulfide crosslinking: a versatile approach to construct mucus-inspired hydrogels
No full textThe remarkable defensive ability of native mucus against pathogens has encouraged scientists to map its structure–-property correlation and its influence on immune defense mechanisms. However, its poorly defined structure, source-dependent composition, and low availability limit the usefulness of native mucus in the laboratory. This gap creates a strong demand for the development of synthetic mucus-mimetic materials. Here, we report a straightforward strategy for constructing mucus-mimetic hydrogels through photo-regulated disulfide crosslinking. Light-responsive 1,2-dithiolane attached to a linear polyglycerol sulfate (lPGS) backbone allows the macromolecular building blocks to crosslink and form the hydrogel, which mirrors the chemistry of native mucus hydrogel formation with its disulfide-linked mucin chains. The viscoelastic properties of the hydrogel can be easily tuned by controlling both the light exposure time and the number of 1,2-dithiolane units within the polymer backbone. Furthermore, localized UV irradiation allows for spatially resolved hydrogel formation. Importantly, this synthetic polymer can directly crosslink with native mucin, bovine submaxillary mucin (BSM), to convert it into a hydrogel at physiological pH. The versatility of this approach – hydrogel formation via photo-regulated disulfide crosslinking – can be used to develop a synthetic mucus model
Estimating realized relatedness in free-ranging macaques by inferring identity-by-descent segments
Get PDFBiological relatedness is a key consideration in studies of behavior, population structure, and trait evolution. Except for parent–offspring dyads, pedigrees capture relatedness imperfectly. The number and length of identical-by-descent DNA segments (IBD) yield the most precise relatedness estimates. Here, we leverage different methods for estimating IBD segments from low-depth whole genome resequencing data to demonstrate the feasibility and value of resolving fine-scaled gradients of relatedness in free-living animals. Using primarily 4 to 6× depth data from a rhesus macaque (Macaca mulatta) population with long-term pedigree data, we show that we can infer the number and length of IBD segments across the genome with high accuracy even at 0.5× sequencing depth. In line with expectations based on simulation, the resulting estimates demonstrate substantial variation in genetic relatedness within kin classes, leading to overlapping distributions between kin classes. By comparing the IBD-based estimates with pedigree and short tandem repeat-based methods, we show that IBD estimates are more reliable and provide more detailed information on kinship. The inferred IBD segments also identify cryptic genetic relatives not represented in the pedigree and reveal elevated recombination rates in females relative to males, which enables the majority of close maternal and paternal kin to be distinguished with genotype data alone. Our findings represent a breakthrough in the ability to study the predictors and consequences of genetic relatedness in natural populations, contributing to our understanding of a fundamental component of population structure in the wild
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Get PDFDigitalisat der Ausgabe von 1913, erschienen 202
Protein aggregation drives cell aging in a size-specific manner in Escherichia coli
No full textAging, the decline in physiological function over time, is marked by the intracellular accumulation of damaged components. It can be attributed to trade-offs between organismal maintenance and the generation of high-quality offspring, where the parent retains damage upon reproduction and produces rejuvenated descendants. This occurs even in bacteria, such as Escherichia coli, which asymmetrically partition aggregates of misfolded proteins upon division. However, there is conflicting evidence on the fitness impact of protein aggregates, ranging from detrimental effects to enhanced stress survival. Here, we show that the decisive factor driving growth decline in E. coli is not the presence of an aggregate, but the fraction of the intracellular space it occupies. By following single-cell E. coli lineages expressing fluorescently labeled DnaK chaperones, we quantified damage accumulation and partitioning across generations in microfluidic devices. We found that the diameter of aggregates increases at linear rates, and cell growth declines as a function of the intracellular space lost to damage. At the same time, however, the mother cell undergoes a progressive enlargement that accommodates the growing aggregate. This could be regarded as a compensatory mechanism, allowing the mother to sustain stable growth despite the continuous accumulation of damage and resulting in the emergence of a morphological asymmetry between mother and daughter cells, challenging the long-standing assumption that E. coli divides symmetrically. Our findings point to a more complex role of protein aggregation, with implications for our understanding of the cellular mechanisms underlying aging, as well as its evolutionary origins