53 research outputs found

    A Distance-Weighted Interaction Map Reveals a Previously Uncharacterized Layer of the Bacillus subtilis Spore Coat

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    SummaryBacillus subtilis spores are encased in a protein assembly called the spore coat that is made up of at least 70 different proteins. Conventional electron microscopy shows the coat to be organized into two distinct layers. Because the coat is about as wide as the theoretical limit of light microscopy, quantitatively measuring the localization of individual coat proteins within the coat is challenging. We used fusions of coat proteins to green fluorescent protein to map genetic dependencies for coat assembly and to define three independent subnetworks of coat proteins. To complement the genetic data, we measured coat protein localization at subpixel resolution and integrated these two data sets to produce a distance-weighted genetic interaction map. Using these data, we predict that the coat comprises at least four spatially distinct layers, including a previously uncharacterized glycoprotein outermost layer that we name the spore crust. We found that crust assembly depends on proteins we predicted to localize to the crust. The crust may be conserved in all Bacillus spores and may play critical functions in the environment

    MAKO: a pathfinder instrument for on-sky demonstration of low-cost 350 micron imaging arrays

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    Submillimeter cameras now have up to 10^4 pixels (SCUBA 2). The proposed CCAT 25-meter submillimeter telescope will feature a 1 degree field-of-view. Populating the focal plane at 350 microns would require more than 10^6 photon-noise limited pixels. To ultimately achieve this scaling, simple detectors and high-density multiplexing are essential. We are addressing this long-term challenge through the development of frequency-multiplexed superconducting microresonator detector arrays. These arrays use lumped-element, direct-absorption resonators patterned from titanium nitride films. We will discuss our progress toward constructing a scalable 350 micron pathfinder instrument focusing on fabrication simplicity, multiplexing density, and ultimately a low per-pixel cost

    Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch

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    Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.Peer reviewe

    Diagnosis and management of Cornelia de Lange syndrome:first international consensus statement

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    Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning

    Reduced growth of Drosophila neurofibromatosis 1 mutants reflects a non-cell-autonomous requirement for GTPase-Activating Protein activity in larval neurons

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    Neurofibromatosis type 1 (NF1) is among the most common genetic disorders of humans and is caused by loss of neurofibromin, a large and highly conserved protein whose only known function is to serve as a GTPase-Activating Protein (GAP) for Ras. However, most Drosophila NF1 mutant phenotypes, including an overall growth deficiency, are not readily modified by manipulating Ras signaling strength, but are rescued by increasing signaling through the cAMP-dependent protein kinase A pathway. This has led to suggestions that NF1 has distinct Ras- and cAMP-related functions. Here we report that the Drosophila NF1 growth defect reflects a non-cell-autonomous requirement for NF1 in larval neurons that express the R-Ras ortholog Ras2, that NF1 is a GAP for Ras1 and Ras2, and that a functional NF1-GAP catalytic domain is both necessary and sufficient for rescue. Moreover, a Drosophila p120RasGAP ortholog, when expressed in the appropriate cells, can substitute for NF1 in growth regulation. Our results show that loss of NF1 can give rise to non-cell-autonomous developmental defects, implicate aberrant Ras-mediated signaling in larval neurons as the primary cause of the NF1 growth deficiency, and argue against the notion that neurofibromin has separable Ras- and cAMP-related functions

    PTEN Loss as Determined by Clinical-grade Immunohistochemistry Assay Is Associated with Worse Recurrence-free Survival in Prostate Cancer.

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    BackgroundPTEN is the most commonly deleted tumor suppressor gene in primary prostate cancer (PCa) and its loss is associated with poor clinical outcomes and ERG gene rearrangement.ObjectiveWe tested whether PTEN loss is associated with shorter recurrence-free survival (RFS) in surgically treated PCa patients with known ERG status.Design setting and participantsA genetically validated, automated PTEN immunohistochemistry (IHC) protocol was used for 1275 primary prostate tumors from the Canary Foundation retrospective PCa tissue microarray cohort to assess homogeneous (in all tumor tissue sampled) or heterogeneous (in a subset of tumor tissue sampled) PTEN loss. ERG status as determined by a genetically validated IHC assay was available for a subset of 938 tumors.Outcome measurements and statistical analysisAssociations between PTEN and ERG status were assessed using Fisher's exact test. Kaplan-Meier and multivariate weighted Cox proportional models for RFS were constructed.Results and limitationsWhen compared to intact PTEN, homogeneous (hazard ratio [HR] 1.66, p = 0.001) but not heterogeneous (HR 1.24, p = 0.14) PTEN loss was significantly associated with shorter RFS in multivariate models. Among ERG-positive tumors, homogeneous (HR 3.07, p < 0.0001) but not heterogeneous (HR 1.46, p = 0.10) PTEN loss was significantly associated with shorter RFS. Among ERG-negative tumors, PTEN did not reach significance for inclusion in the final multivariate models. The interaction term for PTEN and ERG status with respect to RFS did not reach statistical significance (p = 0.11) for the current sample size.ConclusionsThese data suggest that PTEN is a useful prognostic biomarker and that there is no statistically significant interaction between PTEN and ERG status for RFS.Patient summaryWe found that loss of the PTEN tumor suppressor gene in prostate tumors as assessed by tissue staining is correlated with shorter time to prostate cancer recurrence after radical prostatectomy

    A NEaT Design for reliable and scalable network stacks

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    Operating systems provide a wide range of services, which are crucial for the increasingly high reliability and scalability demands of modern applications. Providing both reliability and scalability at the same time is hard. Commodity OS architectures simply lack the design abstractions to do so for demanding core OS services such as the network stack. For reliability and scalability guarantees, they rely almost exclusively on ensuring a high-quality implementation, rather than a reliable and scalable design. This results in complex error recovery paths and hard-to-maintain synchronization code. We demonstrate that a simple and structured design that strictly adheres to two principles, isolation and par- titioning, can yield reliable and scalable network stacks. We present NEaT, a system which partitions the stack across isolated process replicas handling independent requests. Our design principles intelligently partition the state to minimize the impact of failures (offering strong recovery guarantees) and to scale comparably to Linux without exposing the implementation to common pitfalls such as synchronization errors, poor locality, and false sharing
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