The rockefeller university

In marine ecosystems, predators can affect community and ecosystem dynamics through a variety of processes such as foraging facilitation. Here, we report evidence of foraging facilitation between common bottlenose dolphins (Tursiops truncatus) and double-crested cormorants (Nannopterum auritum) in the Caribbean seagrass-dominated atoll of Turneffe, Belize using aerial drone observations conducted in 2015-2017. While dolphins exhibited occasional aggressive behaviours toward the cormorants, the latter frequently followed dolphin movements, suggesting opportunistic pursuit of dolphins for prey access during dolphin bottom foraging activity. Our observations underscore the intricate ecological relationships among marine predators and highlight the need to quantify the mutual benefits and costs of such interactions as coastal ecosystems are rapidly changing.

The origin and fixation of evolutionarily young genes is a fundamental question in evolutionary biology. However, understanding the origins of newly evolved genes arising de novo from noncoding genomic sequences is challenging. This is partly due to the low likelihood that several neutral or nearly neutral mutations fix prior to the appearance of an important novel molecular function. This issue is particularly exacerbated in large effective population sizes where the effect of drift is small. To address this problem, we propose a regulation-focused, cultivator model for de novo gene evolution. This cultivator-focused model posits that each step in a novel variant's evolutionary trajectory is driven by well-defined, selectively advantageous functions for the cultivator genes, rather than solely by the de novo genes, emphasizing the critical role of genome organization in the evolution of new genes.

To explore the influence of genetics on homeostatic regulation of dendritic cell (DC) numbers, we present a screen of DCs and their progenitors in lymphoid and non -lymphoid tissues in Collaborative Cross (CC) and Diversity Outbred (DO) mice. We report 30 and 71 loci with logarithm of the odds (LOD) scores >8.18 and ranging from 6.67 to 8.19, respectively. The analysis reveals the highly polygenic and pleiotropic architecture of this complex trait, including many of the previously identified genetic regulators of DC development and maturation. Two SNPs in genes potentially underlying variation in DC homeostasis, a splice variant in Gramd4 (rs235532740) and a missense variant in Orai3 (rs216659754), are confirmed by gene editing using CRISPRCas9. Gramd4 is a central regulator of DC homeostasis that impacts the entire DC lineage, and Orai3 regulates cDC2 numbers in tissues. Overall, the data reveal a large number of candidate genes regulating DC homeostasis in vivo .

The concept of race is prevalent in medical, nursing, and public health literature. Clinicians often incorporate race into diagnostics, prognostic tools, and treatment guidelines. An example is the recently heavily debated use of race and ethnicity in the Vaginal Birth After Cesarean (VBAC) calculator. In this case, the critics argued that the use of race in this calculator implied that race confers immutable characteristics that affect the ability of women to give birth vaginally after a c-section. This debate is co-occurring as research continues to highlight the racial disparities in health outcomes, such as high maternal mortality among Black women compared to other racial groups in the United States. As the healthcare system contemplates the necessity of utilizing race-a social and political construct, to monitor health outcomes, it has sparked more questions about incorporating race into clinical algorithms, including pulmonary tests, kidney function tests, pharmacotherapies, and genetic testing. This paper critically examines the argument against the race-based Vaginal Birth After Cesarean (VBAC) calculator, shedding light on its implications. Moreover, it delves into the detrimental effects of normalizing race as a biological variable, which hinders progress in improving health outcomes and equity.

Exploring the relationship between neuronal dynamics and ethologically relevant behaviour involves recording neuronal-population activity using technologies that are compatible with unrestricted animal behaviour. However, head-mounted microscopes that accommodate weight limits to allow for free animal behaviour typically compromise field of view, resolution or depth range, and are susceptible to movement-induced artefacts. Here we report a miniaturized head-mounted fluorescent mesoscope that we systematically optimized for calcium imaging at single-neuron resolution, for increased fields of view and depth of field, and for robustness against motion-generated artefacts. Weighing less than 2.5 g, the mesoscope enabled recordings of neuronal-population activity at up to 16 Hz, with 4 mu m resolution over 300 mu m depth-of-field across a field of view of 3.6 x 3.6 mm2 in the cortex of freely moving mice. We used the mesoscope to record large-scale neuronal-population activity in socially interacting mice during free exploration and during fear-conditioning experiments, and to investigate neurovascular coupling across multiple cortical regions. An optimized head-mounted fluorescent mesoscope enables large-scale calcium imaging at single-neuron resolution in freely moving mice, facilitating neurobehavioural studies during social interactions and fear-conditioning experiments.

Optical projection tomography (OPT) is a three-dimensional mesoscopic imaging modality that can use absorption or fluorescence contrast, and is widely applied to fixed and live samples in the mm-cm scale. For fluorescence OPT, we present OPT implemented for accessibility and low cost, an open-source research-grade implementation of modular OPT hardware and software that has been designed to be widely accessible by using low-cost components, including light-emitting diode (LED) excitation and cooled complementary metal-oxide-semiconductor (CMOS) cameras. Both the hardware and software are modular and flexible in their implementation, enabling rapid switching between sample size scales and supporting compressive sensing to reconstruct images from undersampled sparse OPT data, e.g. to facilitate rapid imaging with low photobleaching/phototoxicity. We also explore a simple implementation of focal scanning OPT to achieve higher resolution, which entails the use of a fan-beam geometry reconstruction method to account for variation in magnification. This article is part of the Theo Murphy meeting issue 'Open, reproducible hardware for microscopy'.

A vexing problem in mitochondrial medicine is our limited capacity to evaluate the extent of brain disease in vivo . This limitation has hindered our understanding of the mechanisms that underlie the imaging phenotype in the brain of patients with mitochondrial diseases and our capacity to identify new biomarkers and therapeutic targets. Using comprehensive imaging, we analyzed the metabolic network that drives the brain structural and metabolic features of a mouse model of pyruvate dehydrogenase deficiency (PDHD). As the disease progressed in this animal, in vivo brain glucose uptake and glycolysis increased. Propionate served as a major anaplerotic substrate, predominantly metabolized by glial cells. A combination of propionate and a ketogenic diet extended lifespan, improved neuropathology, and ameliorated motor deficits in these animals. Together, intermediary metabolism is quite distinct in the PDHD brain-it plays a key role in the imaging phenotype, and it may uncover new treatments for this condition.

Neurons from layer II of the entorhinal cortex (ECII) are the first to accumulate tau protein aggregates and degenerate during prodromal Alzheimer's disease. Gaining insight into the molecular mechanisms underlying this vulnerability will help reveal genes and pathways at play during incipient stages of the disease. Here, we use a data-driven functional genomics approach to model ECII neurons in silico and identify the proto-oncogene DEK as a regulator of tau pathology.We show that epigenetic changes caused by Dek silencing alter activity-induced transcription, with major effects on neuronal excitability. This is accompanied by the gradual accumulation of tau in the somatodendritic compartment of mouse ECII neurons in vivo, reactivity of surrounding microglia, and microglia-mediated neuron loss. These features are all characteristic of early Alzheimer's disease.The existence of a cell-autonomous mechanism linking Alzheimer's disease pathogenic mechanisms in the precise neuron type where the disease starts provides unique evidence that synaptic homeostasis dysregulation is of central importance in the onset of tau pathology in Alzheimer's disease. By modelling neurons from the entorhinal cortex in silico, Rodriguez-Rodriguez et al. obtain evidence suggesting that the proto-oncogene DEK is likely to contribute to the vulnerability of these neurons to Alzheimer's disease. Reducing DEK levels in these neurons in vitro leads to changes reminiscent of early Alzheimer's disease pathology.

Dysregulated epigenetic states are a hallmark of cancer and often arise from genetic alterations in epigenetic regulators. This includes missense mutations in histones, which, together with associated DNA, form nucleosome core particles. However, the oncogenic mechanisms of most histone mutations are unknown. Here, we demonstrate that cancer-associated histone mutations at arginines in the histone H3 N-terminal tail disrupt repressive chromatin domains, alter gene regulation, and dysregulate differentiation. We find that histone H3R2C and R26C mutants reduce transcriptionally repressive H3K27me3. While H3K27me3 depletion in cells expressing these mutants is exclusively observed on the minor fraction of histone tails harboring the mutations, the same mutants recurrently disrupt broad H3K27me3 domains in the chromatin context, including near developmentally regulated promoters. H3K27me3 loss leads to de-repression of differentiation pathways, with concordant effects between H3R2 and H3R26 mutants despite different proximity to the PRC2 substrate, H3K27. Functionally, H3R26C-expressing mesenchymal progenitor cells and murine embryonic stem cell-derived teratomas demonstrate impaired differentiation. Collectively, these data show that cancer-associated H3 N-terminal arginine mutations reduce PRC2 activity and disrupt chromatin-dependent developmental functions, a cancer-relevant phenotype. Missense mutations in histones can drive oncogenesis and disrupt chromatin, but the associated mechanisms for many such mutations remain poorly understood. Here, the authors show that cancer-associated histone mutations at arginines in the H3 N-terminal tail disrupt repressive chromatin domains, alter gene expression, and in one case impair differentiation via reduction of PRC2 function.

A search for the production of long-lived particles in proton- proton collisions at a center-of-mass energy of 13 TeVat the CERN LHC is presented. The search is based on data collected by the CMS experiment in 2016-2018, corresponding to a total integrated luminosity of 137 fb(-1). This search is designed to be sensitive to long-lived particles with mean proper decay lengths between 0.1 and 1000 mm, whose decay products produce a final state with at least one displaced vertex and missing transverse momentum. A machine learning algorithm, which improves the background rejection power by more than an order of magnitude, is applied to improve the sensitivity. The observation is consistent with the standard model background prediction, and the results are used to constrain split supersymmetry (SUSY) and gaugemediated SUSY breaking models with different gluino mean proper decay lengths and masses. This search is the first CMS search that shows sensitivity to hadronically decaying long-lived particles from signals with mass differences between the gluino and neutralino below 100 GeV. It sets the most stringent limits to date for split-SUSY models and gauge-mediated SUSY breaking models with gluino proper decay length less than 6 mm.