Mikronavigation
Background/Objectives: Staphylococcus aureus isolates from humans and horses of the equine-associated clonal complexes (CCs) CC1 and CC1660 were comparatively investigated for their genomic relationships. Methods: A total of 91 S. aureus isolates (64 human, 27 equine) were subjected to whole-genome sequencing (WGS), sequence analysis, and antimicrobial susceptibility testing. Results: WGS confirmed 75 CC1 and 16 CC1660 isolates, comprising nine sequence types (STs) in CC1 and four STs in CC1660. Ten spa types were present in CC1 and five in CC1660. In the arcC gene of three CC1 isolates, a 285 bp deletion was detected, and a nucleotide deletion causing a premature stop codon was found in one CC1660 isolate. Core genome (cg) MLST revealed a minimum difference of 1398/1492 alleles between the two CCs. All CC1 isolates harbored agr group III and capsule type 8 alleles, whereas all CC1660 isolates had agr group II and capsule type 5 alleles. Antimicrobial susceptibility testing revealed 18 phenotypic and 19 genotypic resistance patterns. All isolates were susceptible to vancomycin, linezolid and quinupristin–dalfopristin. Several virulence genes were detected in different combinations. The equine leukocidin genes lukP/lukQ were found in 22 isolates from horses and 38 isolates from humans, of which 35 had confirmed contact with horses. No Panton–Valentine leukocidin genes were found. Three human CC1660 isolates carried the toxic shock syndrome toxin-1 gene tst-1. Conclusions: The analysis of the 91 isolates might suggest intra- and interspecies transmission among and between humans and horses, which should be monitored in the future.
Weniger anzeigenPolo is an equestrian sport with a long tradition, but to date there is little scientific data on health risks, particularly lameness. In an international online survey, 145 polo players (47.6% female, 52.4% male) with an average of 13.4 years of playing experience were questioned about lameness risks and influencing factors. The respondents reported a median of six horses, most frequently mares as their best-performing and healthiest animals. Horse age was significantly associated with the risk of lameness, increasing by approximately 19.5% per year (OR = 1.195; p = 0.030) and differed depending on the breed of horse. Player-related variables such as age, sex, level of experience and type of husbandry had no significant influence. Risk perception was only associated with the handicap: players with a higher handicap rated the risk of injury as lower. Sex, age and horse ownership were not relevant. Unfavourable ground conditions were cited as the most common cause of injury (58.6%). The results show that players believe key predictors of lameness, in particular the age and breed of the horses, are objective factors, while subjective risk assessments are primarily influenced by the players’ level of experience. Further studies are necessary to improve horse health in polo and to enable preventive measures.
Weniger anzeigenIn this proof-of-concept study, we show that polyfluorinated trityl radicals with the, to this date, highest fluorination grade can be accessed in quantitative yields in a straightforward manner starting from the perfluorinated trityl cation. The trityl skeleton is functionalized with trimethylsilyl halides to yield perhalofluoro trityl cations, which are subsequently reduced using commercial zinc powder. In this way, we prepare three perhalofluoro trityl radicals and analyze the impact of the fluorine ligands on their electro-optical properties, revealing some interesting trends. In comparison to literature-known polychlorinated trityl radicals, the new polyfluorinated derivatives exhibit substantially higher fluorescence quantum yields, longer luminescence lifetimes, and an expanded emission range that extends into the yellow spectral region. They further display enhanced photostability under light irradiation. In radical-stained polystyrene nanoparticles, an additional broad emission band in the red–NIR wavelength region is observed, which is attributed to excimer formation. Finally, the stability of the new radicals is investigated under ambient conditions, showing the slow conversion with atmospheric oxygen yielding the respective peroxides, which are characterized by single-crystal X-ray diffraction. All in all, our study extends the present scope of luminescent trityl radicals, as the functionalization of the perfluorinated cationic precursor unlocks the path toward a vast variety of polyfluorinated trityl radicals.
Weniger anzeigenSiderophores are low-molecular-weight compounds excreted by microorganisms to acquire iron and possibly to monopolize iron resource to achieve competitive advantage over other strains, or to trade for other substrates in mutualistic relationships. Siderophores that employ β-hydroxy-aspartate (β-OH-Asp) for iron chelation can undergo UV-mediated photolytic cleavage, simultaneously reducing Fe3+ to Fe2+. Photolytic siderophores can promote algal-bacterial mutualism, where the bacteria provide iron in exchange for dissolved organic carbon. We present a comprehensive characterization of cyanochelin B, a photolytic β-OH-Asp-containing siderophore produced by the filamentous cyanobacterium Leptolyngbya sp. NIES-3755. Combining nuclear magnetic resonance, high-resolution mass spectrometry, bioinformatic analyses, and Marfey’s and Murata’s method, we elucidated the structure of cyanochelin B, including the configuration of its stereocenters. Cyanochelin B-iron complexes rapidly photolyse under UV light (t1/2 = 2.3 min; 19.6 µmol m−2 s−1 UV-A) and release Fe2+. Using a coculture setup with Leptolyngbya and Synechocystis sp. PCC 6803 (a non-siderophore producer) in membrane-separated compartments and alginate-embedded FeCl3 to simulate poorly accessible precipitated iron, we demonstrate cyanochelin B mode of actions. Our results show that in the absence of UV light, cyanochelin B efficiently monopolizes iron, favoring Leptolyngbya. However, UV light eliminates this monopolization, making iron available to any cohabiting, also possibly competing, organisms. We further report isolating novel cyanochelin B-producing Phormidesmis strains from field material and discuss the broader implications of photolytic siderophores. In conclusion, our interdisciplinary approach led to the discovery of a novel photolytic siderophore, cyanochelin B, and highlighted its possible role in distributing iron in microbial communities.
Weniger anzeigenPalytoxin (PLTX) and its analogues from Ostreopsis cf. ovata are significant health concerns. They show potent vasoconstrictive properties, often causing seafood poisoning. PLTX analogues have chiral centers, resulting in many isomers, making their separation by liquid chromatography and identification/characterization by mass spectrometry challenging. This study explores for the first time the ion mobility spectrometry (IMS) behavior of these compounds to address these analytical challenges. Drift tube ion mobility spectrometry (DTIMS) and traveling wave ion mobility spectrometry (TWIMS) were used and compared. Additionally, trapped ion mobility spectrometry (TIMS) and molecular dynamics simulation were employed to explain unexpected results. TIMS provided higher resolution, distinguishing isomeric ions generated in the electrospray source by losing water molecules from different toxin sites. Computational studies offered theoretical insights into the ion mobility of triply charged calcium and sodium adduct ions, suggesting a folded conformation. DTCCSN2 (collisional cross section using DTIMS and nitrogen as buffer gas) values were obtained for PLTX (standard), ovatoxin-a, and ovatoxin-b from microalgae samples in Sant Andreu de Llavaneres (Barcelona, Spain). These values were comparable (ΔCCSs < 2%) to those measured with TWIMS calibrated using PLTX (standard). The study provides 102 CCS values from DTIMS and TWIMS data for adducts and fragment ions of PLTX analogues, which can be used as reference values in databases for toxin screening in complex samples.
Weniger anzeigenMaternal care is crucial for primate offspring development, particularly in species with prolonged developmental periods, such as humans and other primates. In this study, we used a cross-species and developmental approach to assess the role of mothers and infants in initiating bouts of affiliation (i.e., proximity and grooming) and visual engagement (i.e., unidirectional and mutual gaze) in humans (N = 10), great apes (N = 18) and small apes (N = 20). We observed mother-infant dyads when the offspring was 1, 6 and 12 months of age, using focal sampling. Our results showed that mothers were generally more likely than infants to initiate grooming, unidirectional and mutual gazes, but not proximity. As infants got older, mothers became even more likely to initiate unidirectional and mutual gazes, but infants also started to initiate proximity and unidirectional gazes more frequently, with infant-initiated mutual gazes peaking at around 6 months of age. Moreover, human mothers were more likely to initiate proximity than great ape mothers, and especially more than small ape mothers; in contrast, infants in great and small apes initiated proximity more frequently than human infants. These findings highlight important similarities between humans and other apes in the initiation patterns of affiliative interactions and visual engagement.
Weniger anzeigenProtein design has focused on the design of ground states, ensuring that they are sufficiently low energy to be highly populated1. Designing the kinetics and dynamics of a system requires, in addition, the design of excited states that are traversed in transitions from one low-lying state to another2,3. This is a challenging task because such states must be sufficiently strained to be poorly populated, but not so strained that they are not populated at all, and because protein design methods have focused on generating near-ideal structures4,5,6,7. Here we describe a general approach for designing systems that use an induced-fit power stroke8 to generate a structurally frustrated9 and strained excited state, allosterically driving protein complex dissociation. X-ray crystallography, double electron–electron resonance spectroscopy and kinetic binding measurements show that incorporating excited states enables the design of effector-induced increases in dissociation rates as high as 5,700-fold. We highlight the power of this approach by designing rapid biosensors, kinetically controlled circuits and cytokine mimics that can be dissociated from their receptors within seconds, enabling dissection of the temporal dynamics of interleukin-2 signalling.
Weniger anzeigenNanodiamonds in water can generate solvated electrons under ultraviolet (UV) excitation, but UV light constitutes only a small portion of solar energy. To harvest solar energy in the visible range, we investigate band gap reduction via surface amino functionalization and examine its impact on photo-excited charge transfer to water. Adamantane, the smallest nanodiamond, is used as a model due to its electron emission properties. Liquid water is first represented using water dimers and then complete solvation shell structures surrounding the adamantane. By systematically analyzing different functionalized adamantane structures, we find that nitrogen serves as the primary electron donor to nearby water molecules. Furthermore, the negative electron affinity of adamantane, which determines its emission capability, is preserved with half of the amino group functionalization on the surface. Our findings motivate further experimental verification using nanodiamonds with amino-functionalized surfaces.
Weniger anzeigenThe Mediterranean Sea is warming at a rate exceeding the global average. Long-term, high-resolution data are essential for contextualizing changes within broader temporal scales, and coral skeletons provide valuable environmental archives, especially in data-sparse regions or as supplements to existing records. While coral-based reconstructions are well established in tropical settings, they remain limited in temperate areas. As the only reef-building zooxanthellate coral in the Mediterranean, Cladocora caespitosa is particularly important for expanding coral-based environmental archives in these understudied regions. Here, we present records of δ18O and δ13C in the skeletons of C. caespitosa from a global change sentinel site in NW Mediterranean. This study provides the most accurate temperature–δ18O calibration equations for C. caespitosa, including a traditional linear model and a novel exponential model that better accounts for the region's wide seasonal temperature range. Both calibrations rely on long-term in situ water temperature data and a multi-corallite composite approach to reduce non-climatic variability. Seasonal trends in δ13C reveal, for the first time, variation in the coral's autotrophy–heterotrophy balance, while geochemical anomalies in the skeletons signal thermal stress effects on biomineralization. Our findings establish C. caespitosa skeletons as critical archives for reconstructing anthropogenic warming and its ecological effects in the Mediterranean.
Weniger anzeigenInfluenza seasonality is influenced by environmental and ecological conditions as well as evolutionary processes shaping the transmission potential of airborne Influenza A virus (IAV) particles and subsequent infectious disease. Considering fluctuating environmental conditions with absolute humidity as a key driver, we analyzed environmental effects on the infection dynamic in Germany during the influenza seasons between 2010 and 2018. Despite the fact that Germany is a comparably homogenous country with regard to socio-economical, and environmental properties, influenza seasons differed significantly between individual German counties and cities, with a clear gradient in incidence and intensity between the Southeast and Northwest. Thus, the transmission of IAV influenced by slight differences in the predominant weather conditions throughout Germany, emphasizing the importance of air temperature and absolute humidity for airborne flu virus transmission.
Weniger anzeigenEdmond Locard's L'enquête criminelle et les méthodes scientifiques marks a pivotal moment in criminology's transformation from a largely unmethodical practice to a scientific discipline. While Locard is best known for advancing laboratory methods of forensic analysis, this article argues that at the heart of his conception of forensics lies the assertion that it is not rationality, but vivid imagination that makes or breaks the criminal investigation. Following Locard's claim that one of the most crucial challenges in teaching forensics is to introduce fellow criminologists to the art of using intuition and creativity for problem-solving, this article examines the concrete ways in which L'enquête criminelle attempts to actively engage the reader's imaginative faculty by presenting problems that can only be solved through “lateral thinking” and “abductive reasoning.” To introduce his speculative methods, I argue, Locard borrows from detective fiction in two ways: Firstly, he counterfactually presents literary case studies by Poe as real-world cases, endorsing Dupin's detective technique as a viable criminological practice. By planting hidden clues and red herrings in semiotic puzzles to be deciphered by the reader, secondly, Locard appropriates narrative techniques to sharpen his reader's hermeneutics instincts.
Weniger anzeigenThe precise quantification of the limits to manipulating quantum resources lies at the core of quantum information theory. However, standard information-theoretic analyses do not consider the actual computational complexity involved in performing certain tasks. Here we address this issue within the realm of entanglement theory, finding that accounting for computational efficiency substantially changes what can be achieved using entangled resources. We consider two key figures of merit: the computational distillable entanglement and the computational entanglement cost. These measures quantify the optimal rates of entangled bits that can be extracted from or used to dilute many identical copies of n-qubit bipartite pure states, using computationally efficient local operations and classical communication. We demonstrate that computational entanglement measures diverge considerably from their information-theoretic counterparts. Whereas the information-theoretic distillable entanglement is determined by the von Neumann entropy of the reduced state, we show that the min-entropy governs the computationally efficient setting. On the other hand, computationally efficient entanglement dilution requires maximal consumption of entangled bits, even for nearly unentangled states. Furthermore, in the worst-case scenario, even when an efficient description of the state exists and is fully known, one gains no advantage over state-agnostic protocols. Our findings establish sample-complexity bounds for measuring and testing the von Neumann entropy, fundamental limitations on efficient state compression and efficient local tomography protocols.
Weniger anzeigenPersisters are phenotypically antibiotic-tolerant cells which can survive antibiotic exposure without acquiring antibiotic resistance. A proposed important factor in persistence is low intracellular ATP levels, which are thought to reduce the activity of antibiotic targets. However, previous studies demonstrated that persisters have comparable DNA damage as drug-sensitive bacteria after fluoroquinolone treatment. Furthermore, recent studies reported that endogenous prophages can reduce levels of antibiotic persistence in Salmonella after fluoroquinolone treatment. In this study, we examined prophage induction and persister cell survival of a prophage-free variant of Salmonella Typhimurium and strains harbouring a deletion of the tisAB genes, with tisB encoding the toxin from the tisB/istR-1 toxin-antitoxin system, known to reduce the intracellular ATP concentration. Treatment of the prophage-free variant with ciprofloxacin resulted in reduced killing and increased persistence as compared to the wild type. In addition, prophage induction and prophage mediated killing was significantly increased after deletion of tisAB following ciprofloxacin treatment. We also demonstrate that the recovery phase following the removal of ciprofloxacin, is crucial for the induction of endogenous prophages. Our results suggest that ATP-dependent prophage activation plays a significant role in DNA damage-mediated killing of bacteria. Low ATP levels can dampen the induction of prophages and increase the fraction of bacterial survivors after ciprofloxacin treatment.
Weniger anzeigenThe BRAF V595E mutation analysis in canine urothelial carcinomas (UCs) has found its way into routine diagnostics, but no data analysis has been published until now. The present study aimed to estimate the distribution of age, sex, and breed in 8365 canine diagnostic samples submitted for BRAF mutation analysis during 2018–2024. The specimens included 8215 urine samples, 17 cytological, and 133 histopathological specimens, and were submitted in cases of suspected UC, to rule out UC, or for screening purposes. All samples were tested for the BRAF V595E mutation using droplet digital PCR (ddPCR). The data were statistically analysed and logistic regression models (Odds Ratio (OR)) were calculated. Compared to samples from mixed-breed dogs, the specimens from Scottish Terriers (OR: 4.21), Shetland Sheepdogs (OR: 2.65), Beagles (OR: 2.33), Fox Terriers (OR: 1.92), Staffordshire Bull Terriers (OR: 1.86), Magyar Vizslas (OR: 1.77), Chihuahuas (OR: 1.70), and West Highland White Terriers (OR: 1.43) had a significantly increased probability of the presence of BRAF mutation indicating UC. The youngest BRAF-positive dogs of these predisposed breeds (n = 4) were 5 years old. In conclusion, screening tests in predisposed breeds may be recommended from the age of 5 years.
Weniger anzeigenHundreds of experiments conducted over the last decades demonstrate a positive relationship between species diversity and ecosystem functions. Following good experimental practice, most of these studies have manipulated species richness artificially by assembling communities randomly. Yet, natural communities along ecological gradients often show niche-based responses to selection gradients and species extinction order is generally not a random process. Such responses are commonly trait-mediated and the effects of communities on ecosystems' functions also depend on species traits. In an effort to disentangle the relationship of trait mean value and diversity with ecosystem functioning, we revisited a community assembly mesocosm experiment that simulated habitat heterogeneity and a typical gradient of productivity to test how body size diversity and composition of cladocerans responded to such gradients and whether and how such trait responses impacted top–down control of unicellular algae, a key ecosystem function in aquatic systems. Nutrient addition lead to an increase in average body size (CWMBS), which ultimately resulted in an increased zooplankton resource use efficiency (RUEZP). This increase in CWMBS acted as a buffer for ecosystems functions despite the decline in species richness under high phosphorus levels. Habitat heterogeneity modified the response of both richness and size diversity (SD) along the nutrient gradient, suggesting that habitat structure provided by aquatic plants can modify zooplankton diversity under eutrophic conditions. We also show that CWMBS and SD are both important and largely independent determinants of variation in RUEZP, whereas the explanatory power of species richness was mostly shared with SD. Overall, our findings illustrate the potential for a key trait, such as body size, to predict top–down control of algae through selection effect mediated by differences in trait mean, as well as complementarity associated with trait diversity among coexisting species.
Weniger anzeigenThe industrially important Cu/ZnO:Al (CZA) catalyst is known as a dynamic system adapting to reaction conditions, which renders the application of in situ and operando methods key to establish structure function correlations. Herein, a CZA catalyst close to the industrially used compostion was studied using noninvasive and bulk-sensitive in situ/operando microwave cavity perturbation technique and electron paramagnetic resonance spectroscopy during activation and reverse water gas shift reaction. The transient changes of catalytic activity track with the transients of the dielectric properties providing evidence for the importance of bulk properties for catalytic activity. Furthermore, convincing support for the redox reaction mechanism is obtained, and it is shown that H2 and CO2 uptake is not competing kinetically with each other. In addition, the reservoir of H2 and CO2 transiently present in the catalyst during catalysis is determined by the chemical potential of the respective reactant, which is directly coupled to the catalytic activity of the system. The findings fit the model of a Schottky barrier at the Cu/ZnO:Al interface, altered by the gas phase composition which in turn alters the catalytic properties of the system.
Weniger anzeigenSaturn’s moon Enceladus ejects a plume of ice grains and gases originating from a subsurface ocean via fractures near its south pole. The chemical characterization of organic material in such ice grains was previously conducted via the analysis of mass spectra obtained in Saturn’s E ring by Cassini’s Cosmic Dust Analyzer at impact speeds below 12 km s−1. Here we present a comprehensive chemical analysis of organic-bearing ice grains sampled directly from the plume during a Cassini fly-by of Enceladus (E5) at an encounter speed of nearly 18 km s−1. We again detect aryl and oxygen moieties in these fresh ice grains, as previously identified in older E-ring grains. Furthermore, the unprecedented high encounter speed revealed previously unobserved molecular fragments in Cosmic Dust Analyzer spectra, allowing the identification of aliphatic, (hetero)cyclic ester/alkenes, ethers/ethyl and, tentatively, N- and O-bearing compounds. These freshly ejected species are derived from the Enceladus subsurface, hinting at a hydrothermal origin and involvement in geochemical pathways towards the synthesis and evolution of organics.
Weniger anzeigenFollowing Russia’s invasion of Ukraine in February 2022, Georgia became a key destination for Russian migrants, who significantly influenced the local housing market. This article explores the impact of the influx of Russian migrants into Tbilisi, which caused a surge in rental prices and aroused feelings of social insecurity among Georgian citizens. Using qualitative methods, including social media analysis and semi-structured interviews, the study investigates the emergence of “informal sanctions” imposed by Georgian Airbnb and Booking.com hosts as a means of expressing political dissatisfaction with their own government and protecting national interests. This article identifies four patterns of informal sanctions, such as rejecting, discomforting, avoiding, and exploiting Russian tenants, which reflect a form of patriotism from below. We argue that these spontaneous, everyday practices of resistance lead to the politicization of mundane host-tenant relations and the collective stereotyping of a migrant group in a time of insecurity. The theoretical proposition here is that everyday nationalism is closely related to informality, which opens the possibility of examining grassroots responses to perceived threats and tactics of resistance, with implications for broader social dynamics in times of ongoing geopolitical conflict and wartime migration in Eastern Europe.
Weniger anzeigenPorcine endogenous retroviruses (PERVs) are integrated into the genome of all pigs. As they can be released as infectious virus particles capable of infecting human cells in vitro, they pose a potential risk for xenotransplantation involving pig cells or organs. To assess whether pigs produce infectious human-tropic viruses, infection assays with human cells are required. There are three main types of assays. First is the incubation of human target cells with gamma-irradiated pig cells. This method ensures that viral transmission is assessed in the absence of replicating pig cells. However, gamma irradiation may alter gene expression in pig cells, potentially affecting the results. Second is the co-culture in a double-chamber system in which pig and human cells are separated by a porous membrane, preventing direct cell-to-cell contact. While this method allows for the detection of infection by free virus particles, it does not account for infection via cell-to-cell transmission, which is a common mode of retroviral infection. And third is the co-culture of pig cells with human cells expressing a resistance gene. The resistance gene allows selective elimination of pig cells upon the addition of a selection medium. This assay enables both free virus and cell-to-cell transmission as well as complete removal of pig cells, which may not be fully achieved in the first type of assay. The third assay best simulates the conditions of in vivo xenotransplantation. However, in all cases the selection of donor and recipient cells is crucial to the experimental outcome. Results only indicate whether a specific pig cell type releases PERVs and whether a specific human cell type is susceptible to infection. A negative infection result does not necessarily reflect the in vivo situation, in which a transplanted organ consists of multiple pig cell types interacting with a diverse range of human cells within a living organism. Knowledge of these limitations is important for authorities regulating clinical applications for xenotransplantation.
Weniger anzeigenThe role of entrepreneurial ecosystems in creating and nurturing new businesses in various regions has been scrutinized for the most part through a macro lens; only a few studies have shed light on the micro-foundations of such systems. What occurs in entrepreneurial ecosystems and how the different actors in them support and affect entrepreneurial journeys has only been researched selectively. Adopting a practice-based perspective that complements current evolutionary and institutional approaches, we will focus on the early journey of business ideas and elucidate how different ecosystem components affect the development and implementation of these ideas in the entrepreneurial process. Using a multiple-case panel design, we studied six startups in the Berlin ecosystem over a two-and-a-half-year period. The findings unveil not only different pathways for enacting support practices, but also that what is provided as support by the ecosystem is not always considered to effectively support entrepreneurial actions.
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