The Mitchell Institute is a 501 non-profit organization in Portland, Maine which has as its mission to increase the likelihood that young people from Maine will aspire to, pursue and achieve a college education.The Institute was founded by George J. Mitchell and is supported by donors throughout Maine. The Institute features a quotation from George J. Mitchell that "no one should be guaranteed success ... but everyone should have a fair chance to succeed." Wikipedia.
News Article | December 19, 2016
Papovich notes that large disk galaxies like our own Milky Way were not always the well-ordered, pinwheel-like, spiral structures we see in the universe today. On the contrary, he and other international experts who specialize in galaxy formation and evolution believe that about 8-to-10 billion years ago, progenitors of the Milky Way and similar disk/spiral galaxies were smaller and less organized, yet highly active in their youth. In previous NASA and National Science Foundation-funded research, Papovich and his collaborators showed that these younger versions of such galaxies were churning out new stars faster than at any other point in their lifespans, suggesting that they must be amazingly rich in star-forming material. And now, they have compelling evidence—the galactic equivalent of a smoking gun. Using the National Radio Astronomy Observatory's Atacama Large Millimeter/submillimeter Array (ALMA)—a huge, highly sophisticated radio telescope array situated at 16,500 feet altitude in the high desert of Chile—a Papovich-led team of astronomers studied four very young versions of galaxies like the Milky Way that are 9 billion light-years distant, meaning the team could see them as they looked approximately 9 billion years ago. They discovered that each galaxy was incredibly rich in carbon monoxide—a well-known tracer of molecular gas, which is the fuel for star formation. The team's findings are reported in a paper posted to arXiv and set to be published in the inaugural issue of Nature Astronomy in January. "We used ALMA to detect adolescent versions of the Milky Way and found that such galaxies do indeed have much higher amounts of molecular gas, which would fuel rapid star formation," said Papovich, lead author on the paper and a member of the George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy. "I liken these galaxies to an adolescent human who consumes prodigious amounts of food to fuel their own growth during their teenage years." In addition to Papovich, the research team also includes fellow Texas A&M astronomers Ryan Quadri and Kim-Vy Tran, as well as astronomers from Leiden Observatory in Holland, Swinburne University and Macquarie University in Australia, the National Optical Astronomy Observatory (NOAO), the University of Texas at Austin, Lyon Observatory in France and the Max Plank Institute for Astronomy in Germany. Though the relative abundance of star-forming gas is extreme in these galaxies, Papovich says they are not yet fully formed and rather small compared to the Milky Way as we see it today. The new ALMA data indicate that the vast majority of the mass in these galaxies is in cold molecular gas rather than in stars—a situation that Papovich says is reversed at present in our Milky Way, where the mass in stars outweighs that in gas by a factor of 10 to 1. These observations, he notes, are helping build a complete picture of how matter in Milky-Way-size galaxies evolved and how our own galaxy formed. "Most stars today exist in galaxies like the Milky Way, so by studying how galaxies like our own formed, we've come to understand the most typical locations of stars in the universe," said Papovich, a member since 2008 of the Texas A&M Department of Physics and Astronomy, where he is a co-holder of the Marsha L. '69 and Ralph F. Schilling '68 Chair in Experimental Physics. "Our current research shows that Milky Way-mass galaxies appear to accumulate most of their gas during their first few billion years of history. At that stage, they have most of the fuel they need to produce the stars they currently encompass in the present." The presence of extensive gas reservoirs backs up the team's previous observations that provided the first tangible pictures showcasing the unprecedented life story of Milky Way galaxy evolution. Among other details, their prior study revealed a stellar birth rate 30 times higher than it is in the Milky Way today—roughly one per year, compared to about 30 each year 9.5 billion years ago. "Thanks to ALMA and other innovative instruments that allow us to peer 9 billion years into the past to analyze galaxies that are likely similar to the progenitor of our own Milky Way galaxy, we can actually prove what our observations show," Papovich said. Papovich and his team recently have been awarded more highly competitive time with ALMA to study the temperature and density of the star-forming gas, allowing them to measure and map its transitions and phases and ideally the related impacts within the galaxies. "This will begin to tell us how these galaxies formed stars at such a rapid pace, compared to conditions at present," he said. Papovich, Quadri and Tran are among roughly two dozen astronomers around the world who have spent years studying carefully selected distant galaxies similar in mass to the progenitor of our own Milky Way that were found in two deep-sky program surveys of the universe, the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and the FourStar Galaxy Evolution Survey (ZFOURGE). Beyond ALMA, the team's research has used observations from NASA's Hubble and Spitzer Space Telescopes and the European Space Agency's Herschel Space Observatory. The Hubble images from the CANDELS survey also provided structural information about galaxy sizes and how they evolved. Far-infrared light observations from Spitzer and Herschel helped the astronomers trace the star-formation rate. The team's paper, Large Molecular Gas Reservoirs in Ancestors of Milky Way-Mass Galaxies 9 Billion Years Ago, can be viewed online along with related images and captions. Explore further: Our Sun came late to the Milky Way's star-birth party More information: C. Papovich et al. Large molecular gas reservoirs in ancestors of Milky Way-mass galaxies nine billion years ago, Nature Astronomy (2016). DOI: 10.1038/s41550-016-0003
Jansson J.K.,Lawrence Berkeley National Laboratory |
Jansson J.K.,Mitchell Institute |
Jansson J.K.,Joint BioEnergy Institute |
Jansson J.K.,Copenhagen University |
And 2 more authors.
Nature Reviews Microbiology | Year: 2014
Permafrost constitutes a major portion of the terrestrial cryosphere of the Earth and is a unique ecological niche for cold-adapted microorganisms. There is a relatively high microbial diversity in permafrost, although there is some variation in community composition across different permafrost features and between sites. Some microorganisms are even active at subzero temperatures in permafrost. An emerging concern is the impact of climate change and the possibility of subsequent permafrost thaw promoting microbial activity in permafrost, resulting in increased potential for greenhouse-gas emissions. This Review describes new data on the microbial ecology of permafrost and provides a platform for understanding microbial life strategies in frozen soil as well as the impact of climate change on permafrost microorganisms and their functional roles. © 2014 Macmillan Publishers Limited. All rights reserved.
Silke J.,Walter and Eliza Hall Institute of Medical Research |
Meier P.,Mitchell Institute
Cold Spring Harbor Perspectives in Biology | Year: 2013
Misregulated innate immune signaling and cell death form the basis of much human disease pathogenesis. Inhibitor of apoptosis (IAP) protein family members are frequently overex- pressed in cancer and contribute to tumor cell survival, chemo-resistance, disease progres- sion, and poor prognosis. Although best known for theirabilitytoregulate caspases, IAPs also influence ubiquitin (Ub)-dependent pathways that modulate innate immune signaling via activation of nuclear factor kB (NF-kB). Recent research into IAP biology has unearthed unexpected roles for this group of proteins. In addition, the advances in our understanding of the molecular mechanisms that IAPs use to regulate cell death and innate immune re- sponses have provided new insights into disease states and suggested novel intervention strategies. Here we review the functions assigned to those IAP proteins that act at the inter- section of cell death regulation and inflammatory signaling. © 2013 Cold Spring Harbor Laboratory Press; all rights reserved.
Sullivan T.P.,University of British Columbia |
Sullivan D.S.,Mitchell Institute
Forest Ecology and Management | Year: 2012
Coarse woody debris (CWD) has many ecological functions ranging from conservation of biodiversity to long-term ecosystem productivity. Wildlife habitat, in particular, has been the focus of CWD investigations aimed at maintaining mammal species in managed forests. Piles and windrows of post-harvest woody debris could be designed to provide connectivity and habitat across clearcut openings for a wide array of mammalian species. Populations of microtines, such as the long-tailed vole (Microtus longicaudus), occur in early successional post-harvest habitats with vegetative and CWD cover, and may be potential pests feeding on newly planted trees. The role of CWD as habitat structures that attract voles and perhaps their predators may be part of a predator/prey pest-control scenario. Thus, we tested three hypotheses (H) that woody debris arranged in large piles and windrows, at a real-world scale, would increase (H1) the abundance, reproduction, and survival of long-tailed voles; (H2) the relative abundance of small weasels (Mustela spp.), and (H3) the incidence of feeding damage by voles to planted seedlings, compared with a dispersed (conventional) treatment on clearcut sites. Long-tailed voles were intensively live-trapped from 2007 to 2009 in replicated woody debris treatments of dispersed, piles, and windrows near Summerland in south-central British Columbia, Canada.Mean abundance of long-tailed voles was significantly higher (6.4-8.0 times) in treatment sites with piles and windrows than in the dispersed CWD treatment. Patterns in reproduction, recruitment, and survival generally followed those of abundance. There was a curvilinear regression relationship (r=0.72; P<0.01) between mean abundance of long-tailed voles and mean volume of CWD per ha across the dispersed, piles, and windrow treatments. A range of 400-600m3/ha of CWD in piles or windrows was required as habitat for viable populations of long-tailed voles on these clearcuts, at least during this 3-year period. Winter snow tracking data indicated that there was significantly more weasel activity in the treatment sites with piles than those with dispersed CWD, and similar activity in the dispersed and windrow sites. The predictions of H1 and H2 were supported. The incidence of feeding damage (<10%) by voles to planted seedlings was similar among treatment sites, and hence H3 was not supported. Based on the results of our 3-year study, woody debris structures do not appear to create conditions for buildup of Microtus populations to " pest status" such that newly planted trees are at risk from feeding damage. © 2011 Elsevier B.V.
Lowe C.J.,Stanford University |
Clarke D.N.,Stanford University |
Medeiros D.M.,University of Colorado at Boulder |
Rokhsar D.S.,University of California at Berkeley |
And 3 more authors.
Nature | Year: 2015
Our understanding of vertebrate origins is powerfully informed by comparative morphology, embryology and genomics of chordates, hemichordates and echinoderms, which together make up the deuterostome clade. Striking body-plan differences among these phyla have historically hindered the identification of ancestral morphological features, but recent progress in molecular genetics and embryology has revealed deep similarities in body-axis formation and organization across deuterostomes, at stages before morphological differences develop. These developmental genetic features, along with robust support of pharyngeal gill slits as a shared deuterostome character, provide the foundation for the emergence of chordates. © 2015 Macmillan Publishers Limited. All rights reserved.
Darding M.,Mitchell Institute |
Meier P.,Mitchell Institute
Cell Death and Differentiation | Year: 2012
Deregulation of innate immune signalling and cell death form the basis of most human disease pathogenesis. Inhibitor of APoptosis (IAP) protein-family members are frequently overexpressed in cancer and contribute to tumour cell survival, chemo-resistance, disease progression and poor prognosis. Although best known for their ability to regulate caspases, IAPs also influence ubiquitin-dependent pathways that modulate innate immune signalling by activation of NF-κB. Recent advances in our understanding of the molecular mechanisms through which IAPs influence cell death and innate immune responses have provided new insights into novel strategies for treatment of cancer. In this review we discuss our current understanding of IAP-mediated NF-κB signalling, as well as elaborate on unexpected insights into the involvement of IAPs in regulating the Ripoptosome, a novel intrinsic cell death-inducing platform. We propose an evolutionarily conserved concept whereby IAPs function as guardians of killer platforms such as the apoptosome in Drosophila and the Ripoptosome in mammals. © 2012 Macmillan Publishers Limited All rights reserved.
Pagani I.,Mitchell Institute |
Liolios K.,Mitchell Institute |
Jansson J.,Mitchell Institute |
Chen I.-M.A.,Lawrence Berkeley National Laboratory |
And 4 more authors.
Nucleic Acids Research | Year: 2012
The Genomes OnLine Database (GOLD, http://www .genomesonline.org/) is a comprehensive resource for centralized monitoring of genome andmetagenome projects worldwide. Both complete and ongoing projects, along with their associated metadata, can be accessed in GOLD through precomputed tables and a search page. As of September 2011, GOLD, now on version 4.0, contains information for 11 472 sequencing projects, of which 2907 have been completed and their sequence data has been deposited in a public repository. Out of these complete projects, 1918 are finished and 989 are permanent drafts. Moreover, GOLD contains information for 340 metagenome studies associated with 1927 metagenome samples. GOLD continues to expand, moving toward the goal of providing the most comprehensive repository of metadata information related to the projects and their organisms/environments in accordance with the Minimum Information about any (x) Sequence specification and beyond.
Harris L.G.,Mitchell Institute |
Samant R.S.,Mitchell Institute |
Shevde L.A.,Mitchell Institute
Molecular Cancer Research | Year: 2011
In addition to its role in embryonic development, the Hedgehog pathway has been shown to be an active participant in cancer development, progression, and metastasis. Although this pathway is activated by autocrine signaling by Hedgehog ligands, it can also initiate paracrine signaling with cells in the microenvironment. This creates a network of Hedgehog signaling that determines the malignant behavior of the tumor cells. As a result of paracrine signal transmission, the effects of Hedgehog signaling most profoundly influence the stromal cells that constitute the tumor microenvironment. The stromal cells in turn produce factors that nurture the tumor. Thus, such a resonating cross-talk can amplify Hedgehog signaling, resulting in molecular chatter that overall promotes tumor progression. Inhibitors of Hedgehog signaling have been the subject of intense research. Several of these inhibitors are currently being evaluated in clinical trials. Here, we review the role of the Hedgehog pathway in the signature characteristics of cancer cells that determine tumor development, progression, and metastasis. This review condenses the latest findings on the signaling pathways that are activated and/or regulated by molecules generated from Hedgehog signaling in cancer and cites promising clinical interventions. Finally, we discuss future directions for identifying the appropriate patients for therapy, developing reliable markers of efficacy of treatment, and combating resistance to Hedgehog pathway inhibitors. ©2011 AACR.
Kudo K.,Mitchell Institute
Nucleic acids research | Year: 2010
We have developed a new approach to systematically study post-transcriptional regulation in a small number of cells. Actively translating mRNAs are associated with polysomes and the newly synthesized peptide chains are closely associated with molecular chaperones such as hsp70s, which assist in the proper folding of nascent polypeptides into higher ordered structures. These chaperones provide an anchor with which to separate actively translating mRNAs associated with polysomes from free mRNAs. Affinity capture beads were developed to capture hsp70 chaperones associated with the polysome complexes. The isolated actively translating mRNAs were used for high-throughput expression profiling analysis. Feasibility was demonstrated using an in vitro translation system with known translationally regulated mRNA transcript thymidylate synthase (TS). We further developed the approach using HCT-116 colon cancer cells with both TS and p53 as positive controls. The steady-state levels of TS and p53 mRNAs were unaltered after 5-fluorouracil treatment as assessed by real-time qRT-PCR analysis. In contrast, the protein expression and polysome-associated mRNA levels of both genes were increased. These differences in translational rate were revealed with our new approach from 500 cells. This technology has the potential to make investigation of translational control feasible with limited quantities of clinical specimens.
Lopez J.,Mitchell Institute |
Meier P.,Mitchell Institute
Current Opinion in Cell Biology | Year: 2010
The processes of dying are as tightly regulated as those of growth and proliferation, and together they establish a finely tuned balance that ensures proper organ size and function. Failure in the regulation of these responses lies at the heart of many human diseases. Certain members of the inhibitor of apoptosis (IAP) protein family function as important gatekeepers of cell death and survival. While IAPs can regulate cell death by controlling caspases, they also modulate other signalling processes that impact on cell viability. Probably the most important contribution of IAPs to cell survival and tumorigenesis resides in the ability of a number of IAPs to act as ubiquitin-E3 ligases regulating NF-κB signalling. Here, we discuss the latest insights into the ubiquitin-related roles of IAPs and how this contributes to the survival of cells and the organism. © 2010 Elsevier Ltd.