Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms

This is the author accepted manuscript. The final version is available from the American Association for the Advancement of Science via the DOI in this recordTrue physiological imaging of subcellular dynamics requires studying cells within their parent organisms, where all the environmental cues that drive gene expression, and hence the phenotypes that we actually observe, are present. A complete understanding also requires volumetric imaging of the cell and its surroundings at high spatiotemporal resolution, without inducing undue stress on either. We combined lattice light-sheet microscopy with adaptive optics to achieve, across large multicellular volumes, noninvasive aberration-free imaging of subcellular processes, including endocytosis, organelle remodeling during mitosis, and the migration of axons, immune cells, and metastatic cancer cells in vivo. The technology reveals the phenotypic diversity within cells across different organisms and developmental stages and may offer insights into how cells harness their intrinsic variability to adapt to different physiological environments.Howard Hughes Medical Institute (HHMI)BiogenIonis PharmaceuticalsNational Institutes of Health (NIH)University of ExeterCarol M. Baldwin FoundationDamon Runyon Cancer Research FoundationNational Science Foundation (NSF)Pew Charitable Trust

Navigating at night: fundamental limits on the sensitivity of radical pair magnetoreception under dim light

Night-migratory songbirds appear to sense the direction of the Earth's magnetic field via radical pair intermediates formed photochemically in cryptochrome flavoproteins contained in photoreceptor cells in their retinas. It is an open question whether this light-dependent mechanism could be sufficiently sensitive given the low-light levels experienced by nocturnal migrants. The scarcity of available photons results in significant uncertainty in the signal generated by the magnetoreceptors distributed around the retina. Here we use results from Information Theory to obtain a lower bound estimate of the precision with which a bird could orient itself using only geomagnetic cues. Our approach bypasses the current lack of knowledge about magnetic signal transduction and processing in vivo by computing the best-case compass precision under conditions where photons are in short supply. We use this method to assess the performance of three plausible cryptochrome-derived flavin-containing radical pairs as potential magnetoreceptors

Core Use-Life Distributions in Lithic Assemblages as a Means for Reconstructing Behavioral Patterns

Artifacts with varying use-lives have different discard rates and hence are represented unequally among archaeological assemblages. As such, the ability to gauge the use-lives of artifacts is important for understanding the formation of archaeological assemblage variability. In lithic artifacts, use-life can be expressed as the extraction of utility, or work potential, from existing stone volume. Using experimental data and generalized linear modeling, this study develops models of artifact use-life on cores in the form of reduction intensity. We then apply these models to two archaeological case studies to (a) reconstruct the reduction intensities of archaeological cores and (b) investigate the survivorship curves of these archaeological cores across the reduction continuum using the Weibull function. Results indicate variation in core reduction and maintenance with respect to raw material properties and place use history and implicate evolutionary differences between Early Stone Age hominins and Holocene modern humans

The "Sete Fontes" groundwater system (Braga, NW Portugal): historical milestones and urban assessment

Water resource assessment is essential to bring about sustainable growth of urban development and overall economic progress. Climate change and population growth pressure are important drivers in the available water resources. The crucial point of water management should be to promote an integrated water management in a river catchment and associated groundwater systems. The ancient drinking water system from Sete Fontes (Braga, northern Portugal) was built in the middle-eighteen century, and was the main water supply system of the city until 1913. This water system is located in a valley, with a NE-SW trend, promoting a favourable gentle slope to water gravity transport into the city. The Sete Fontes aquifer is characterized by Silurian metasediments intruded by Variscan granites, with two main fracturation trends - ENE-WSW and NW-SE. The mainly hydrogeochemistry is Na-Cl facies and locally Na-HCO3 facies. The groundwater is poorly mineralized, suggesting meteoric water contribution, with a relatively shallow circuit. During the Roman period, Sete Fontes system was probably the main source of water for the city. The economic, and demographic expansion of Braga lead to the increasing use of other water resources. Presently, the city primary delivery system is only supplied surface water from Cávado catchment. Natural groundwater characteristics from Sete Fontes shows that it is still suitable for human consumption and also to non-potable uses. The assessment also suggests that this is a sustainable water resource, that can constitute an important backup solution in case of failure of the main delivery system due to scarcity or catastrophe.This work is co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI01-0145-FEDER-007690 and national funds provided by Fundação para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio