202 research outputs found

    The Vibrio cholerae virulence regulatory cascade controls glucose uptake through activation of TarA, a small regulatory RNA

    Full text link
    Vibrio cholerae causes the severe diarrhoeal disease cholera. A cascade of regulators controls expression of virulence determinants in V. cholerae at both transcriptional and post-transcriptional levels. ToxT is the direct transcription activator of the major virulence genes in V. cholerae . Here we describe TarA, a highly conserved, small regulatory RNA, whose transcription is activated by ToxT from toxboxes present upstream of the ToxT-activated gene tcpI . TarA regulates ptsG , encoding a major glucose transporter in V. cholerae . Cells overexpressing TarA exhibit decreased steady-state levels of ptsG mRNA and grow poorly in glucose-minimal media. A mutant lacking the ubiquitous regulatory protein Hfq expresses diminished TarA levels, indicating that TarA likely interacts with Hfq to regulate gene expression. RNAhybrid analysis of TarA and the putative ptsG mRNA leader suggests potential productive base-pairing between these two RNA molecules. A V. cholerae mutant lacking TarA is compromised for infant mouse colonization in competition with wild type, suggesting a role in the in vivo fitness of V. cholerae . Although somewhat functionally analogous to SgrS of Escherichia coli , TarA does not encode a regulatory peptide, and its expression is activated by the virulence gene pathway in V. cholerae and not by glycolytic intermediates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79165/1/j.1365-2958.2010.07397.x.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/79165/2/MMI_7397_sm_TableS1.pd

    Genetic Differentiation Between Western and Eastern (Eschrichtius robustus) Gray Whale Populations Using Microsatellite Markers

    Get PDF
    ABSTRACT Within the North Pacific, gray whales (Eschrichtius robustus) are recognized as distinct eastern and western populations. Although both populations were severely reduced by whaling, the eastern population is generally considered to have recovered while the western population has remained highly depleted. Previous studies have documented genetic differentiation between the two populations on the basis of mtDNA haplotype frequencies. Since mtDNA represents only maternal inheritance patterns, the present study used bi-parentally inherited microsatellite markers (n=13) to measure differentiation between populations as well as to compare levels of nuclear genetic diversity retained in each. Mean levels of genetic diversity, as measured by the microsatellites, were similar between the eastern and western populations, indicating that the western population has retained relatively high levels of nuclear genetic diversity despite its small size. Comparison of microsatellite allele frequencies confirmed that eastern and western populations are genetically distinct. Although highly statistically significant, the level of differentiation between the two populations is relatively low, and sex-specific analyses suggest that some amount of male-biased dispersal may occur between populations. While these results suggest some movements between the eastern and western populations may take place, the maintenance of genetic differences between the two populations supports their recognition as separate eastern and western populations. Future efforts should focus on elucidating the nature and extent of any dispersal which is occurring in order to better understand factors potentially influencing the recovery of the small western population

    Perspectives on Astrophysics Based on Atomic, Molecular, and Optical (AMO) Techniques

    Get PDF
    About two generations ago, a large part of AMO science was dominated by experimental high energy collision studies and perturbative theoretical methods. Since then, AMO science has undergone a transition and is now dominated by quantum, ultracold, and ultrafast studies. But in the process, the field has passed over the complexity that lies between these two extremes. Most of the Universe resides in this intermediate region. We put forward that the next frontier for AMO science is to explore the AMO complexity that describes most of the Cosmos.Comment: White paper submission to the Decadal Assessment and Outlook Report on Atomic, Molecular, and Optical (AMO) Science (AMO 2020

    Thyroid and hepatic function after high-dose 131 I-metaiodobenzylguanidine ( 131 I-MIBG) therapy for neuroblastoma.

    Full text link
    Background 131 I-Metaiodobenzylguanidine ( 131 I-MIBG) provides targeted radiotherapy for children with neuroblastoma, a malignancy of the sympathetic nervous system. Dissociated radioactive iodide may concentrate in the thyroid, and 131 I-MIBG is concentrated in the liver after 131 I-MIBG therapy. The aim of our study was to analyze the effects of 131 I-MIBG therapy on thyroid and liver function. Procedure Pre- and post-therapy thyroid and liver functions were reviewed in a total of 194 neuroblastoma patients treated with 131 I-MIBG therapy. The cumulative incidence over time was estimated for both thyroid and liver toxicities. The relationship to cumulative dose/kg, number of treatments, time from treatment to follow-up, sex, and patient age was examined. Results In patients who presented with Grade 0 or 1 thyroid toxicity at baseline, 12 ± 4% experienced onset of or worsening to Grade 2 hypothyroidism and one patient developed Grade 2 hyperthyroidism by 2 years after 131 I-MIBG therapy. At 2 years post- 131 I-MIBG therapy, 76 ± 4% patients experienced onset or worsening of hepatic toxicity to any grade, and 23 ± 5% experienced onset of or worsening to Grade 3 or 4 liver toxicity. Liver toxicity was usually transient asymptomatic transaminase elevation, frequently confounded by disease progression and other therapies. Conclusion The prophylactic regimen of potassium iodide and potassium perchlorate with 131 I-MIBG therapy resulted in a low rate of significant hypothyroidism. Liver abnormalities following 131 I-MIBG therapy were primarily reversible and did not result in late toxicity. 131 I-MIBG therapy is a promising treatment for children with relapsed neuroblastoma with a relatively low rate of symptomatic thyroid or hepatic dysfunction. Pediatr Blood Cancer 2011;56:191–201. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78497/1/22767_ftp.pd

    Family physician leadership during the COVID-19 pandemic: roles, functions and key supports.

    Get PDF
    PURPOSE: Strong leadership in primary care is necessary to coordinate an effective pandemic response; however, descriptions of leadership roles for family physicians are absent from previous pandemic plans. This study aims to describe the leadership roles and functions family physicians played during the COVID-19 pandemic in Canada and identify supports and barriers to formalizing these roles in future pandemic plans. DESIGN/METHODOLOGY/APPROACH: This study conducted semi-structured qualitative interviews with family physicians across four regions in Canada as part of a multiple case study. During the interviews, participants were asked about their roles during each pandemic stage and the facilitators and barriers they experienced. Interviews were transcribed and a thematic analysis approach was used to identify recurring themes. FINDINGS: Sixty-eight family physicians completed interviews. Three key functions of family physician leadership during the pandemic were identified: conveying knowledge, developing and adapting protocols for primary care practices and advocacy. Each function involved curating and synthesizing information, tailoring communications based on individual needs and building upon established relationships. PRACTICAL IMPLICATIONS: Findings demonstrate the need for future pandemic plans to incorporate formal family physician leadership appointments, as well as supports such as training, communication aides and compensation to allow family physicians to enact these key roles. ORIGINALITY/VALUE: The COVID-19 pandemic presents a unique opportunity to examine the leadership roles of family physicians, which have been largely overlooked in past pandemic plans. This study\u27s findings highlight the importance of these roles toward delivering an effective and coordinated pandemic response with uninterrupted and safe access to primary care

    The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

    Get PDF
    Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella

    Catching Element Formation In The Act

    Full text link
    Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions.Comment: 14 pages including 3 figure

    Analysis of the putative role of CR1 in Alzheimer’s disease: Genetic association, expression and function

    Get PDF
    Chronic activation of the complement system and induced inflammation are associated with neuropathology in Alzheimer's disease (AD). Recent large genome wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) in the C3b/C4b receptor (CR1 or CD35) that are associated with late onset AD. Here, anti-CR1 antibodies (Abs) directed against different epitopes of the receptor, were used to localize CR1 in brain, and relative binding affinities of the CR1 ligands, C1q and C3b, were assessed by ELISA. Most Abs tested stained red blood cells in blood vessels but showed no staining in brain parenchyma. However, two monoclonal anti-CR1 Abs labeled astrocytes in all of the cases tested, and this reactivity was preabsorbed by purified recombinant human CR1. Human brain-derived astrocyte cultures were also reactive with both mAbs. The amount of astrocyte staining varied among the samples, but no consistent difference was conferred by diagnosis or the GWAS-identified SNPs rs4844609 or rs6656401. Plasma levels of soluble CR1 did not correlate with diagnosis but a slight increase was observed with rs4844609 and rs6656401 SNP. There was also a modest but statistically significant increase in relative binding activity of C1q to CR1 with the rs4844609 SNP compared to CR1 without the SNP, and of C3b to CR1 in the CR1 genotypes containing the rs6656401 SNP (also associated with the larger isoform of CR1) regardless of clinical diagnosis. These results suggest that it is unlikely that astrocyte CR1 expression levels or C1q or C3b binding activity are the cause of the GWAS identified association of CR1 variants with AD. Further careful functional studies are needed to determine if the variant-dictated number of CR1 expressed on red blood cells contributes to the role of this receptor in the progression of AD, or if another mechanism is involved
    • …
    corecore