572 research outputs found

    A Pipeline for Volume Electron Microscopy of the Caenorhabditis elegans Nervous System.

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    The "connectome," a comprehensive wiring diagram of synaptic connectivity, is achieved through volume electron microscopy (vEM) analysis of an entire nervous system and all associated non-neuronal tissues. White et al. (1986) pioneered the fully manual reconstruction of a connectome using Caenorhabditis elegans. Recent advances in vEM allow mapping new C. elegans connectomes with increased throughput, and reduced subjectivity. Current vEM studies aim to not only fill the remaining gaps in the original connectome, but also address fundamental questions including how the connectome changes during development, the nature of individuality, sexual dimorphism, and how genetic and environmental factors regulate connectivity. Here we describe our current vEM pipeline and projected improvements for the study of the C. elegans nervous system and beyond

    Understanding strategic road network users’ experiences and need – Wave 2

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    In 2011, the Government called for an independent review, to assess whether they were taking the right approach to managing, operating and enhancing the Strategic Road Network (SRN), which resulted in the Cook Report ‘A Fresh Start for the Strategic Road Network’. Since then, there has been further need to inform the development of policy in this area. The Department for Transport commissioned a wide programme of social research, involving quantitative and qualitative strands, to respond to this need. This report arises from Wave 2 of the qualitative research, conducted by TNS BMRB and the Centre for Transport & Society at UWE Bristol following the Government’s publication of ‘Action for Roads: A Network for the 21st Century’ , a Command Paper highlighting the challenges faced on England’s roads, reiterating the need for investment and setting out detailed plans to improve management of the network. Wave 2 also builds on the first wave of qualitative research, conducted in May and June 2013, which examined attitudes to the performance of the SRN and the need for further investment in it (see Understanding Road Users: qualitative research into use of and attitudes towards the Strategic Road Network; wave 1 report). Wave 2 therefore stands alone as an independent piece of research, but the reports should also be seen as complementary

    Native Chemical Ligation−Photodesulfurization in Flow

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    Native chemical ligation (NCL) combined with desulfurization chemistry has revolutionized the way in which large polypeptides and proteins are accessed by chemical synthesis. Herein, we outline the use of flow chemistry for the ligation-based assembly of polypeptides. We also describe the development of a novel photodesulfurization transformation that, when coupled with flow NCL, enables efficient access to native polypeptides on time scales up to 2 orders of magnitude faster than current batch NCL–desulfurization methods. The power of the new ligation–photodesulfurization flow platform is showcased through the rapid synthesis of the 36 residue clinically approved HIV entry inhibitor enfuvirtide and the peptide diagnostic agent somatorelin.ARC Future Fellowship Scheme 25

    Better Health, Better Lives? 10-Years on From the World Health Organization's Declaration on the Health of Children With Intellectual Disabilities.

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    It is now 10 years since the European Declaration on the Health of Children and Young People with Intellectual Disabilities and their Families: Better Health - Better Lives was adopted by the World Health Organization. Through discussions with key informants and an online literature review, we reflect on actions and progress made in line with this Declaration to improve the health and wellbeing of children with intellectual disabilities and their families. Despite finding positive examples of policy, legislation and practice in support of children with intellectual disabilities, there are clear gaps and areas for improvement. Countries must continue to take action, as supported by the World Health Organization and other such organisations, in order to support children with intellectual disabilities in realising their fundamental human rights

    A JWST/NIRCam Study of Key Contributors to Reionization: The Star-forming and Ionizing Properties of UV-faint z∼7−8z\sim7-8 Galaxies

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    Spitzer/IRAC imaging has revealed that the brightest z∼7−8z\sim7-8 galaxies often exhibit young ages and strong nebular line emission, hinting at high ionizing efficiency among early galaxies. However, IRAC's limited sensitivity has long hindered efforts to study the fainter, more numerous population often thought largely responsible for reionization. Here we use CEERS JWST/NIRCam data to characterize 116 UV-faint (median MUV=−19.5_{UV}=-19.5) z∼6.5−8z\sim6.5-8 galaxies. The SEDs are typically dominated by young (∼\sim10-50 Myr), low-mass (M∗∼108 M⊙M_\ast\sim10^8\ M_\odot) stellar populations, and we find no need for extremely high stellar masses (∼1011M⊙\sim10^{11} M_\odot). Considering previous studies of UV-bright (MUV∼−22_{UV}\sim-22) z∼7−8z\sim7-8 galaxies, we find evidence for a strong (5-10×\times) increase in specific star formation rate toward lower luminosities (median sSFR=103 Gyr−1^{-1} in CEERS). The larger sSFRs imply a more dominant contribution from OB stars in the relatively numerous UV-faint population, perhaps suggesting that these galaxies are very efficient ionizing agents (median ξion=1025.7\xi_{ion}=10^{25.7} erg−1^{-1} Hz). In spite of their much larger sSFRs, we find no significant increase in [OIII]++Hβ\beta EWs towards fainter MUV_{UV} (median ≈\approx780 A˚\mathring{A}). If confirmed, this may indicate that a substantial fraction of our CEERS galaxies possess extremely low metallicities (≲\lesssim3% Z⊙Z_\odot) where [OIII] emission is suppressed. Alternatively, high ionizing photon escape fractions or bursty star formation histories can also weaken the nebular lines in a subset of our CEERS galaxies. While the majority of our objects are very blue (median β=−2.0\beta=-2.0), we identify a significant tail of very dusty galaxies (β∼−1\beta\sim-1) at ≈\approx0.5LUV∗L_{UV}^\ast which may contribute significantly to the z∼7−8z\sim7-8 star formation rate density.Comment: Accepted in MNRAS. Updated to use the most recent NIRCam zeropoints. There are no significant changes to the conclusions relative to v

    Phosphonate production by marine microbes: exploring new sources and potential function

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Acker, M., Hogle, S. L., Berube, P. M., Hackl, T., Coe, A., Stepanauskas, R., Chisholm, S. W., & Repeta, D. J. Phosphonate production by marine microbes: exploring new sources and potential function. Proceedings of the National Academy of Sciences of the United States of America, 119(11), (2022): e2113386119, https://doi.org/10.1073/pnas.2113386119.Phosphonates are organophosphorus metabolites with a characteristic C-P bond. They are ubiquitous in the marine environment, their degradation broadly supports ecosystem productivity, and they are key components of the marine phosphorus (P) cycle. However, the microbial producers that sustain the large oceanic inventory of phosphonates as well as the physiological and ecological roles of phosphonates are enigmatic. Here, we show that phosphonate synthesis genes are rare but widely distributed among diverse bacteria and archaea, including Prochlorococcus and SAR11, the two major groups of bacteria in the ocean. In addition, we show that Prochlorococcus can allocate over 40% of its total cellular P-quota toward phosphonate production. However, we find no evidence that Prochlorococcus uses phosphonates for surplus P storage, and nearly all producer genomes lack the genes necessary to degrade and assimilate phosphonates. Instead, we postulate that phosphonates are associated with cell-surface glycoproteins, suggesting that phosphonates mediate ecological interactions between the cell and its surrounding environment. Our findings indicate that the oligotrophic surface ocean phosphonate pool is sustained by a relatively small fraction of the bacterioplankton cells allocating a significant portion of their P quotas toward secondary metabolism and away from growth and reproduction.This work was supported in part by grants from the NSF (OCE-1153588 and DBI-0424599 to S.W.C.; OCE-1335810 and OIA-1826734 to R.S.; and OCE-1634080 to D.J.R.), the Gordon and Betty Moore Foundation (no. 6000 to D.J.R.), and the Simons Foundation (Life Sciences Project Award IDs 337262 and 647135 to S.W.C.; 510023 to R.S.; and Simons Collaboration on Ocean Processes and Ecology [SCOPE] Award ID 329108 to S.W.C. and D.J.R.)

    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
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