569 research outputs found

    Considerations for Young Men (Part 1)

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    Written by Rev J. B. Waterbury, author of Advice to a Young Christian and other books, Considerations for Young Men is a series of 32 letters which the author intended for young men as they left their parents\u27 homes, ...as a manual which the hand of Christian benevolence might offer to a friend. These letters are group into larger categories; in this section can be found Pleasures and Anticipations, in which the author considers the pleasures and problems of childhood and youth, and Dangers and Temptations, in which the author warns young men of the temptations of wealth, honor, dishonesty, pride, and temptations specific to colleges and towns.https://openworks.wooster.edu/motherhomeheaven/1056/thumbnail.jp

    Considerations for Young Men (Part 2)

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    Written by Rev J. B. Waterbury, author of Advice to a Young Christian and other books, Considerations for Young Men is a series of 32 letters which the author intended for young men as they left their parents\u27 homes, ...as a manual which the hand of Christian benevolence might offer to a friend. This section of the book contains letters completing the section devoted to temptations by discussing the temptations of the theatre, gambling, and alcohol. It also contains letters in the category of Prejudices Against Religion, in which the author discusses the youthful prejudices against religion and the importance of religion.https://openworks.wooster.edu/motherhomeheaven/1057/thumbnail.jp

    Selection and maintenance of sexual identity in the Drosophila germline.

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    Unlike sex determination in the soma, which is an autonomous process, sex determination in the germline of Drosophila has both inductive and autonomous components. In this paper, we examined how sexual identity is selected and maintained in the Drosophila germline. We show that female-specific expression of genes in the germline is dependent on a somatic signaling pathway. This signaling pathway requires the sex-non-specific transformer 2 gene but, surprisingly, does not appear to require the sex-specific genes, transformer and doublesex. Moreover, in contrast to the soma where pathway initiation and maintenance are independent processes, the somatic signaling pathway appears to function continuously from embryogenesis to the larval stages to select and sustain female germline identity. We also show that the primary target for the somatic signaling pathway in germ cells can not be the Sex-lethal gene

    The Lamprey Genome: Illuminating Genomic Change across Eons and Embryogenesis

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    The lamprey genome provides unique insights into both the deep evolutionary history of vertebrate genomes and the maintenance of genome structure/integrity over development. The lamprey lineage diverged from all other vertebrates approximately 500 million years ago. As such, comparisons between lamprey and other vertebrates permit reconstruction of ancient duplication and rearrangement events that defined the fundamental architecture and gene content of all extant vertebrate genomes. Lamprey also undergoes programmatic changes genome structure that result in the physical elimination of ~20% of its genomic DNA (~0.5Gb from a ~2 Gb genome) from all somatic cell lineages during early embryonic development. Here, we outline recent progress in assembly and analysis of the lamprey germline genome, and progress in the development of methods for characterizing the cellular events that mediate DNA elimination. We have integrated information from several sampling approaches and sequencing technologies to achieve a highly contiguous assembly of lamprey genome (including: Illumina fragments/mate pairs, 20X coverage in Pacific Biosciences reads, dense meiotic maps and optical mapping data). This genome assembly has dramatically improved our ability to dissect the molecular basis and genetic outcomes of programmed genome rearrangements (PGRs), and has improved our understanding of the tempo and mode of large-­scale duplications and translocations within the ancestral vertebrate lineage. Analysis of the germline genome identifies several genes that are expressed in germline but physically eliminated from all somatic tissues. These eliminated genes correspond to several known oncogenes and appear to identify several other novel oncogene candidates. Complementing this assembly, the development of approaches to in situ analysis of 3D preserved cells has revealed that PGR unfolds through a series of dramatic cellular events that involve the programmatic alteration of several fundamental mechanisms of genome maintenance, including: alignment of chromosomes at metaphase, chromatid cohesion, separation and segregation, and nuclear envelope formation

    Closely related phytoplankton species produce similar suites of dissolved organic matter

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    © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 5 (2014): 111, doi:10.3389/fmicb.2014.00111.Production of dissolved organic matter (DOM) by marine phytoplankton supplies the majority of organic substrate consumed by heterotrophic bacterioplankton in the sea. This production and subsequent consumption converts a vast quantity of carbon, nitrogen, and phosphorus between organic and inorganic forms, directly impacting global cycles of these biologically important elements. Details regarding the chemical composition of DOM produced by marine phytoplankton are sparse, and while often assumed, it is not currently known if phylogenetically distinct groups of marine phytoplankton release characteristic suites of DOM. To investigate the relationship between specific phytoplankton groups and the DOM they release, hydrophobic phytoplankton-derived dissolved organic matter (DOMP) from eight axenic strains was analyzed using high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Identification of DOM features derived from Prochlorococcus, Synechococcus, Thalassiosira, and Phaeodactylum revealed DOMP to be complex and highly strain dependent. Connections between DOMP features and the phylogenetic relatedness of these strains were identified on multiple levels of phylogenetic distance, suggesting that marine phytoplankton produce DOM that in part reflects its phylogenetic origin. Chemical information regarding the size and polarity ranges of features from defined biological sources was also obtained. Our findings reveal DOMP composition to be partially conserved among related phytoplankton species, and implicate marine DOM as a potential factor influencing microbial diversity in the sea by acting as a link between autotrophic and heterotrophic microbial community structures.This research was supported by grants to Daniel J. Repeta and Sallie W. Chisholm from the Gordon and Betty Moore Foundation and funding to Daniel J. Repeta, Edward F. DeLong, and Sallie W. Chisholm from the National Science Foundation Science and Technology Center Award 0424599

    Iron conservation by reduction of metalloenzyme inventories in the marine diazotroph Crocosphaera watsonii

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    The marine nitrogen fixing microorganisms (diazotrophs) are a major source of nitrogen to open ocean ecosystems and are predicted to be limited by iron in most marine environments. Here we use global and targeted proteomic analyses on a key unicellular marine diazotroph Crocosphaera watsonii to reveal large scale diel changes in its proteome, including substantial variations in concentrations of iron metalloproteins involved in nitrogen fixation and photosynthesis, as well as nocturnal flavodoxin production. The daily synthesis and degradation of enzymes in coordination with their utilization results in a lowered cellular metalloenzyme inventory that requires ~40% less iron than if these enzymes were maintained throughout the diel cycle. This strategy is energetically expensive, but appears to serve as an important adaptation for confronting the iron scarcity of the open oceans. A global numerical model of ocean circulation, biogeochemistry and ecosystems suggests that Crocosphaera’s ability to reduce its iron-metalloenzyme inventory provides two advantages: It allows Crocosphaera to inhabit regions lower in iron and allows the same iron supply to support higher Crocosphaera biomass and nitrogen fixation than if they did not have this reduced iron requirement.National Science Foundation (U.S.). Chemical and Biological Oceanography Program (OCE-0452883)National Science Foundation (U.S.). Chemical and Biological Oceanography Program (OCE-0752291)National Science Foundation (U.S.). Chemical and Biological Oceanography Program (OCE-0723667)National Science Foundation (U.S.). Chemical and Biological Oceanography Program (OCE-0928414)National Science Foundation (U.S.). Polar Program (ANT-0732665)United States. Environmental Protection Agency (Star Fellowship)Woods Hole Oceanographic Institution. Ocean Life InstituteCenter for Microbial Oceanography: Research and EducationCenter for Environmental Bioinorganic Chemistr

    Highly conserved molecular pathways, including Wnt signaling, promote functional recovery from spinal cord injury in lampreys

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    © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 742, doi:10.1038/s41598-017-18757-1.In mammals, spinal cord injury (SCI) leads to dramatic losses in neurons and synaptic connections, and consequently function. Unlike mammals, lampreys are vertebrates that undergo spontaneous regeneration and achieve functional recovery after SCI. Therefore our goal was to determine the complete transcriptional responses that occur after SCI in lampreys and to identify deeply conserved pathways that promote regeneration. We performed RNA-Seq on lamprey spinal cord and brain throughout the course of functional recovery. We describe complex transcriptional responses in the injured spinal cord, and somewhat surprisingly, also in the brain. Transcriptional responses to SCI in lampreys included transcription factor networks that promote peripheral nerve regeneration in mammals such as Atf3 and Jun. Furthermore, a number of highly conserved axon guidance, extracellular matrix, and proliferation genes were also differentially expressed after SCI in lampreys. Strikingly, ~3% of differentially expressed transcripts belonged to the Wnt pathways. These included members of the Wnt and Frizzled gene families, and genes involved in downstream signaling. Pharmacological inhibition of Wnt signaling inhibited functional recovery, confirming a critical role for this pathway. These data indicate that molecular signals present in mammals are also involved in regeneration in lampreys, supporting translational relevance of the model.We gratefully acknowledge support from the National Institutes of Health (R03NS078519 to OB; R01GM104123 to JJS; R01NS078165 to JRM), The Feinstein Institute for Medical Research and The Marine Biological Laboratory, including the Charles Evans Foundation Research Award, the Albert and Ellen Grass Foundation Faculty Research Award, and The Eugene and Millicent Bell Fellowship Fund in Tissue Engineering
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