Mitigation of Quantum Dot Cytotoxicity by Microencapsulation

When CdSe/ZnS-polyethyleneimine (PEI) quantum dots (QDs) are microencapsulated in polymeric microcapsules, human fibroblasts are protected from acute cytotoxic effects. Differences in cellular morphology, uptake, and viability were assessed after treatment with either microencapsulated or unencapsulated dots. Specifically, QDs contained in microcapsules terminated with polyethylene glycol (PEG) mitigate contact with and uptake by cells, thus providing a tool to retain particle luminescence for applications such as extracellular sensing and imaging. The microcapsule serves as the “first line of defense” for containing the QDs. This enables the individual QD coating to be designed primarily to enhance the function of the biosensor

Structural Perturbations to Population Skeletons: Transient Dynamics, Coexistence of Attractors and the Rarity of Chaos

Simple models of insect populations with non-overlapping generations have been instrumental in understanding the mechanisms behind population cycles, including wild (chaotic) fluctuations. The presence of deterministic chaos in natural populations, however, has never been unequivocally accepted. Recently, it has been proposed that the application of chaos control theory can be useful in unravelling the complexity observed in real population data. This approach is based on structural perturbations to simple population models (population skeletons). The mechanism behind such perturbations to control chaotic dynamics thus far is model dependent and constant (in size and direction) through time. In addition, the outcome of such structurally perturbed models is [almost] always equilibrium type, which fails to commensurate with the patterns observed in population data.We present a proportional feedback mechanism that is independent of model formulation and capable of perturbing population skeletons in an evolutionary way, as opposed to requiring constant feedbacks. We observe the same repertoire of patterns, from equilibrium states to non-chaotic aperiodic oscillations to chaotic behaviour, across different population models, in agreement with observations in real population data. Model outputs also indicate the existence of multiple attractors in some parameter regimes and this coexistence is found to depend on initial population densities or the duration of transient dynamics. Our results suggest that such a feedback mechanism may enable a better understanding of the regulatory processes in natural populations

A comprehensive characterization of the caspase gene family in insects from the order Lepidoptera

<p>Abstract</p> <p>Background</p> <p>The cell suicide pathway of apoptosis is a necessary event in the life of multicellular organisms. It is involved in many biological processes ranging from development to the immune response. Evolutionarily conserved proteases, called caspases, play a central role in regulating apoptosis. Reception of death stimuli triggers the activation of initiator caspases, which in turn activate the effector caspases. In Lepidoptera, apoptosis is crucial in processes such as metamorphosis or defending against baculovirus infection. The discovery of p35, a baculovirus protein inhibiting caspase activity, has led to the characterization of the first lepidopteran caspase, Sf-Caspase-1. Studies on Sf-Caspase-1 mode of activation suggested that apoptosis in Lepidoptera requires a cascade of caspase activation, as demonstrated in many other species.</p> <p>Results</p> <p>In order to get insights into this gene family in Lepidoptera, we performed an extensive survey of lepidopteran-derived EST datasets. We identified 66 sequences distributed among 27 species encoding putative caspases. Phylogenetic analyses showed that Lepidoptera possess at least 5 caspases, for which we propose a unified nomenclature. According to homology to their <it>Drosophila </it>counterparts and their primary structure, we determined that Lep-Caspase-1, -2 and -3 are putative effector caspases, whereas Lep-Caspase-5 and -6 are putative initiators. The likely function of Lep-Caspase-4 remains unclear. Lep-Caspase-2 is absent from the silkworm genome and appears to be noctuid-specific, and to have arisen from a tandem duplication of the Caspase-1 gene. In the tobacco hawkmoth, 3 distinct transcripts encoding putative Caspase-4 were identified, suggesting at least 2 duplication events in this species.</p> <p>Conclusions</p> <p>The basic repertoire of five major types of caspases shared among Lepidoptera seems to be smaller than for most other groups studied to date, but gene duplication still plays a role in lineage-specific increases in diversity, just as in Diptera and mammals.</p

Native diversity buffers against severity of non-native tree invasions.

This is the final version. Available from Nature Research via the DOI in this record. Data availability: Data used in this study can be found in cited references for the Global Naturalized Alien Flora (GloNAF) database6 (non-native status), the KEW Plants of the World database5 (native ranges) and the Global Environmental Composite63,77 (environmental data layers). Plant trait data were extracted from Maynard et al.78. Data from the Global Forest Biodiversity Initiative (GFBI) database57 are not available due to data privacy and sharing restrictions, but can be obtained upon request via Science-I (https://science-i.org/) or GFBI (gfbinitiative.org) and an approval from data contributors.Code availability All code used to complete analyses for the manuscript is available at the following link: https://github.com/thomaslauber/Global-Tree-Invasion. Data analyses were conducted and were visualizations generated in R (v. 4.2.2), Python (v. 3.9.7), Google Earth Engine (earthengine-api 0.1.306), QGIS-LTR (v. 3.16.7) and the ETH Zurich Euler cluster.Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions.Swiss National Science FoundationSwiss National Science FoundationBernina FoundationDOB Ecolog

The global biogeography of tree leaf form and habit

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: Tree occurrence data from the Global Forest Biodiversity initiative (GFBi) is available upon request via Science-I (https://science-i.org) or the GFBi website (https://www.gfbiinitiative.org/). Information on leaf habit (evergreen vs deciduous) and leaf form (broadleaved vs needle-leaved) came from the TRY database (https://www.try-db.org). Additional, leaf-type data came from the Tallo dataset (https://zenodo.org/record/6637599). Plot-level soil information came from the World Soil Information Service (WOSIS) dataset (https://www.isric.org/explore/wosis).Code availability: All code is available at https://doi.org/10.5281/zenodo.7967245.Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling

Temperature and pressure dependence of direct current electrical resistivity in the Na2O-ZnO-B2O3 glass system

Two series of glasses were prepared, xNa2O, yZnO, 100 - x - yB2O3 and 30 - xNa2O, xZnO, 70B2O3 (mol%). The temperature dependence of the direct current resistivity was measured from room temperature to about 700 K and in both series of glasses we observed a simple Arrhenius type of temperature dependence. However, the resistivity of the binary alkali glass increased steeply by as much as two orders of magnitude with the addition of even a small quantity of ZnO and remained virtually unaffected by further addition of ZnO. The resistivity decreases gradually with increasing pressure in Na2O-B2O3 but increases with increasing pressure with the addition of ZnO

Not Available

Not AvailableStudies were carried out to investigate the reasons underlying farmers’ motivation to conserve mango diversity particularly of indigenous varieties. At four project sites, viz., Chittoor, Malihabad, Pusa and Sirsi, 48 custodian farmers were identified. The results of the analysis indicated that it is not only the economic factors (market value, 79%), but also other factors such as personal (63%), social (52%), cultural/religious (14%), natural (48%) factors and biological traits (52%) which motivate farmers to conserve specific varieties while maintaining mango diversity. Further, while all the custodians maintained the diversity, some others (34%) also promoted and adapted the diversity. For promotion of mango diversity conservation, value addition to diversity and linking mango diversity to markets through diversity fairs, stakeholders’ meeting, and roadside stalls will have to be given priority. National policy support in the form of establishing a network of custodian farmers and skill up gradation (grafting, management of genetic resources) and registration.Not Availabl