65 research outputs found

    Functions of height and width dimensions in the intertidal mussel, Mytilus californianus

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    Author Posting. © National Shellfisheries Association, 2008. This article is posted here by permission of National Shellfisheries Association for personal use, not for redistribution. The definitive version was published in Journal of Shellfish Research 27 (2008): 385-392, doi:10.2983/0730-8000(2008)27[385:FOHAWD]2.0.CO;2.A mussel's shell records its history of growth. We investigated variability in the size and shape of mussel shells of Mytilus californianus Conrad (1837) to test the hypothesis that the mussel shell provides information on the contemporary condition of the mussel. Two factors were associated with shape: an epithelial discoloration and the Sr/Ca in the shell nacre. Sr/Ca data distinguished the mussel populations as did a discriminate analysis that included the trace metal ratios; Sr/Ca, Mg/Ca, Mn/Ca, Ag/Ca, Cd/Ca, Ba/Ca, and Pb/Ca. Size varied independently of shape and was not associated with the two factors. However, a null model that describes the morphological variability in height and width suggests that mussel size also plays a central role in partitioning phenotypic variability. These analyses of contemporary factors coupled with analyses of morphological variability holds promise for addressing the functional roles of mussel height and width and what proportion of phenotypic variability can be attributed to environmental factors

    UNC1062, a new and potent Mer inhibitor

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    Abnormal activation of Mer kinase has been implicated in the oncogenesis of many human cancers including acute lymphoblastic and myeloid leukemia, non-small cell lung cancer, and glioblastoma. We have discovered a new family of small molecule Mer inhibitors, pyrazolopyrimidine sulfonamides, that potently inhibit the kinase activity of Mer. Importantly, these compounds do not demonstrate significant hERG activity in the PatchXpress assay. Through structure-activity relationship studies, 35 (UNC1062) was identified as a potent (IC50 = 1.1 nM) and selective Mer inhibitor. When applied to live tumor cells, UNC1062 inhibited Mer phosphorylation and colony formation in soft agar. Given the potential of Mer as a therapeutic target, UNC1062 is a promising candidate for further drug development

    UNC569, a Novel Small-Molecule Mer Inhibitor with Efficacy against Acute Lymphoblastic Leukemia In Vitro and In Vivo

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    Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Although survival rates have improved, patients with certain biological subtypes still have suboptimal outcomes. Current chemotherapeutic regimens are associated with short- and long-term toxicities and novel, less toxic therapeutic strategies are needed. Mer receptor tyrosine kinase is ectopically expressed in ALL patient samples and cell lines. Inhibition of Mer expression reduces pro-survival signaling, increases chemosensitivity, and delays development of leukaemia in vivo suggesting that Mer tyrosine kinase inhibitors are excellent candidates for targeted therapies. Brain and spinal tumors are the second most common malignancies in childhood. Multiple chemotherapy approaches and radiation have been attempted, yet overall survival remains dismal. Mer is also abnormally expressed in atypical teratoid/rhabdoid tumors (ATRT), providing a rationale for targeting Mer as a therapeutic strategy. We have previously described UNC569, the first small molecule Mer inhibitor. This manuscript describes the biochemical and biological effects of UNC569 in ALL and ATRT. UNC569 inhibited Mer activation and downstream signaling through ERK1/2 and AKT, determined by western blot analysis. Treatment with UNC569 reduced proliferation/survival in liquid culture, decreased colony formation in methylcellulose/soft agar, and increased sensitivity to cytotoxic chemotherapies. MYC transgenic zebrafish with T-ALL were treated with UNC569 (4 µM for 2 weeks). Fluorescence was quantified as indicator of the distribution of lymphoblasts, which express Mer and enhanced green fluorescent protein. UNC569 induced >50% reduction in tumor burden compared to vehicle- and mock-treated fish. These data support further development of Mer inhibitors as effective therapies in ALL and ATRT

    Discovery of a chemical probe for the L3MBTL3 methyllysine reader domain

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    We describe the discovery of UNC1215, a potent and selective chemical probe for the methyl-lysine (Kme) reading function of L3MBTL3, a member of the malignant brain tumor (MBT) family of chromatin interacting transcriptional repressors. UNC1215 binds L3MBTL3 with a Kd of 120 nM, competitively displacing mono- or dimethyl-lysine containing peptides, and is greater than 50-fold selective versus other members of the MBT family while also demonstrating selectivity against more than 200 other reader domains examined. X-ray crystallography identified a novel 2:2 polyvalent mode of interaction. In cells, UNC1215 is non-toxic and binds directly to L3MBTL3 via the Kme-binding pocket of the MBT domains. UNC1215 increases the cellular mobility of GFP-L3MBTL3 fusion proteins and point mutants that disrupt the Kme binding function of GFP-L3MBTL3 phenocopy the effects of UNC1215. Finally, UNC1215 demonstrates a novel Kme-dependent interaction of L3MBTL3 with BCLAF1, a protein implicated in DNA damage repair and apoptosis

    Comparative Phylogeography of a Coevolved Community: Concerted Population Expansions in Joshua Trees and Four Yucca Moths

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    Comparative phylogeographic studies have had mixed success in identifying common phylogeographic patterns among co-distributed organisms. Whereas some have found broadly similar patterns across a diverse array of taxa, others have found that the histories of different species are more idiosyncratic than congruent. The variation in the results of comparative phylogeographic studies could indicate that the extent to which sympatrically-distributed organisms share common biogeographic histories varies depending on the strength and specificity of ecological interactions between them. To test this hypothesis, we examined demographic and phylogeographic patterns in a highly specialized, coevolved community – Joshua trees (Yucca brevifolia) and their associated yucca moths. This tightly-integrated, mutually interdependent community is known to have experienced significant range changes at the end of the last glacial period, so there is a strong a priori expectation that these organisms will show common signatures of demographic and distributional changes over time. Using a database of >5000 GPS records for Joshua trees, and multi-locus DNA sequence data from the Joshua tree and four species of yucca moth, we combined paleaodistribution modeling with coalescent-based analyses of demographic and phylgeographic history. We extensively evaluated the power of our methods to infer past population size and distributional changes by evaluating the effect of different inference procedures on our results, comparing our palaeodistribution models to Pleistocene-aged packrat midden records, and simulating DNA sequence data under a variety of alternative demographic histories. Together the results indicate that these organisms have shared a common history of population expansion, and that these expansions were broadly coincident in time. However, contrary to our expectations, none of our analyses indicated significant range or population size reductions at the end of the last glacial period, and the inferred demographic changes substantially predate Holocene climate changes

    Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq

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    We present optical, infrared, ultraviolet, and radio observations of SN 2022xkq, an underluminous fast-declining type Ia supernova (SN Ia) in NGC 1784 (D31\mathrm{D}\approx31 Mpc), from <1<1 to 180 days after explosion. The high-cadence observations of SN 2022xkq, a photometrically transitional and spectroscopically 91bg-like SN Ia, cover the first days and weeks following explosion which are critical to distinguishing between explosion scenarios. The early light curve of SN 2022xkq has a red early color and exhibits a flux excess which is more prominent in redder bands; this is the first time such a feature has been seen in a transitional/91bg-like SN Ia. We also present 92 optical and 19 near-infrared (NIR) spectra, beginning 0.4 days after explosion in the optical and 2.6 days after explosion in the NIR. SN 2022xkq exhibits a long-lived C I 1.0693 μ\mum feature which persists until 5 days post-maximum. We also detect C II λ\lambda6580 in the pre-maximum optical spectra. These lines are evidence for unburnt carbon that is difficult to reconcile with the double detonation of a sub-Chandrasekhar mass white dwarf. No existing explosion model can fully explain the photometric and spectroscopic dataset of SN 2022xkq, but the considerable breadth of the observations is ideal for furthering our understanding of the processes which produce faint SNe Ia.Comment: 38 pages, 16 figures, accepted for publication in ApJ, the figure 15 input models and synthetic spectra are now available at https://zenodo.org/record/837925

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Adaptive responses of animals to climate change are most likely insufficient

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    Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.Peer reviewe

    The western painted turtle genome, a model for the evolution of extreme physiological adaptations in a slowly evolving lineage

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    Background: We describe the genome of the western painted turtle, Chrysemys picta bellii, one of the most widespread, abundant, and well-studied turtles. We place the genome into a comparative evolutionary context, and focus on genomic features associated with tooth loss, immune function, longevity, sex differentiation and determination, and the species' physiological capacities to withstand extreme anoxia and tissue freezing.Results: Our phylogenetic analyses confirm that turtles are the sister group to living archosaurs, and demonstrate an extraordinarily slow rate of sequence evolution in the painted turtle. The ability of the painted turtle to withstand complete anoxia and partial freezing appears to be associated with common vertebrate gene networks, and we identify candidate genes for future functional analyses. Tooth loss shares a common pattern of pseudogenization and degradation of tooth-specific genes with birds, although the rate of accumulation of mutations is much slower in the painted turtle. Genes associated with sex differentiation generally reflect phylogeny rather than convergence in sex determination functionality. Among gene families that demonstrate exceptional expansions or show signatures of strong natural selection, immune function and musculoskeletal patterning genes are consistently over-represented.Conclusions: Our comparative genomic analyses indicate that common vertebrate regulatory networks, some of which have analogs in human diseases, are often involved in the western painted turtle's extraordinary physiological capacities. As these regulatory pathways are analyzed at the functional level, the painted turtle may offer important insights into the management of a number of human health disorders
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