4,652 research outputs found
Ecophysiological traits of grasses: resolving the effects of photosynthetic pathway and phylogeny
C4 photosynthesis is an important example of convergent evolution in plants, having arisen in eudicots, monocots and diatoms. Comparisons between such diverse groups are confounded by phylogenetic and ecological differences, so that only broad generalisations can be made about the role of C4 photosynthesis in
determining ecophysiological traits. However, 60% of C4 species occur in the grasses (Poaceae) and molecular phylogenetic techniques confirm that there are between 8 and 17 independent origins of C4 photosynthesis in the Poaceae. In a screening experiment, we compared leaf physiology and growth traits across several major
independent C3 & C4 groups within the Poaceae, asking 1) which traits differ consistently between photosynthetic
types and 2) which traits differ consistently between clades within each photosynthetic type
Cost-effectiveness of health care service delivery interventions in low and middle income countries : a systematic review
Background
Low and middle income countries (LMICs) face severe resource limitations but the highest burden of disease. There is a growing evidence base on effective and cost-effective interventions for these diseases. However, questions remain about the most cost-effective method of delivery for these interventions. We aimed to review the scope, quality, and findings of economic evaluations of service delivery interventions in LMICs.
Methods
We searched PUBMED, MEDLINE, EconLit, and NHS EED for studies published between 1st January 2000 and 30th October 2016 with no language restrictions. We included all economic evaluations that reported incremental costs and benefits or summary measures of the two such as an incremental cost effectiveness ratio. Studies were grouped by both disease area and outcome measure and permutation plots were completed for similar interventions. Quality was judged by the Drummond checklist.
Results
Overall, 3818 potentially relevant abstracts were identified of which 101 studies were selected for full text review. Thirty-seven studies were included in the final review. Twenty-three studies reported on interventions we classed as âchanging by whom and where care was providedâ, specifically interventions that entailed task-shifting from doctors to nurses or community health workers or from facilities into the community. Evidence suggests this type of intervention is likely to be cost-effective or cost-saving. Nine studies reported on quality improvement initiatives, which were generally found to be cost-effective. Quality and methods differed widely limiting comparability of the studies and findings.
Conclusions
There is significant heterogeneity in the literature, both methodologically and in quality. This renders further comparisons difficult and limits the utility of the available evidence to decision makers
Evidence against Wolbachia symbiosis in Loa loa
BACKGROUND: The majority of filarial nematode species are host to Wolbachia bacterial endosymbionts, although a few including Acanthocheilonema viteae, Onchocerca flexuosa and Setaria equina have been shown to be free of infection. Comparisons of species with and without symbionts can provide important information on the role of Wolbachia symbiosis in the biology of the nematode hosts and the contribution of the bacteria to the development of disease. Previous studies by electron microscopy and PCR have failed to detect intracellular bacterial infection in Loa loa. Here we use molecular and immunohistological techniques to confirm this finding. METHODS: We have used a combination of PCR amplification of bacterial genes (16S ribosomal DNA [rDNA], ftsZ and Wolbachia surface protein [WSP]) on samples of L. loa adults, third-stage larvae (L3) and microfilariae (mf) and immunohistology on L. loa adults and mf derived from human volunteers to determine the presence or absence of Wolbachia endosymbionts. Samples used in the PCR analysis included 5 adult female worms, 4 adult male worms, 5 mf samples and 2 samples of L3. The quality and purity of nematode DNA was tested by PCR amplification of nematode 5S rDNA and with diagnostic primers from the target species and used to confirm the absence of contamination from Onchocerca sp., Mansonella perstans, M. streptocerca and Wuchereria bancrofti. Immunohistology was carried out by light and electron microscopy on L. loa adults and mf and sections were probed with rabbit antibodies raised to recombinant Brugia malayi Wolbachia WSP. Samples from nematodes known to be infected with Wolbachia (O. volvulus, O. ochengi, Litomosoides sigmodontis and B. malayi) were used as positive controls and A. viteae as a negative control. RESULTS: Single PCR analysis using primer sets for the bacterial genes 16S rDNA, ftsZ, and WSP were negative for all DNA samples from L. loa. Positive PCR reactions were obtained from DNA samples derived from species known to be infected with Wolbachia, which confirmed the suitability of the primers and PCR conditions. The quality and purity of nematode DNA samples was verified by PCR amplification of 5S rDNA and with nematode diagnostic primers. Additional analysis by 'long PCR' failed to produce any further evidence for Wolbachia symbiosis. Immunohistology of L. loa adults and mf confirmed the results of the PCR with no evidence for Wolbachia symbiosis. CONCLUSION: DNA analysis and immunohistology provided no evidence for Wolbachia symbiosis in L. loa
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The land plant-specific MIXTA-MYB lineage is implicated in the early evolution of the plant cuticle and the colonization of land.
The evolution of a lipid-based cuticle on aerial plant surfaces that protects against dehydration is considered a fundamental innovation in the colonization of the land by the green plants. However, key evolutionary steps in the early regulation of cuticle synthesis are still poorly understood, owing to limited studies in early-diverging land plant lineages. Here, we characterize a land plant specific subgroup 9 R2R3 MYB transcription factor MpSBG9, in the early-diverging land plant model Marchantia polymorpha, that is homologous to MIXTA proteins in vascular plants. The MpSBG9 functions as a key regulator of cuticle biosynthesis by preferentially regulating expression of orthologous genes for cutin formation, but not wax biosynthesis genes. The MpSBG9 also promotes the formation of papillate cells on the adaxial surface of M. polymorpha, which is consisitent with its canonical role in vascular plants. Our observations imply conserved MYB transcriptional regulation in the control of the cutin biosynthesis pathway as a core genetic network in the common ancestor of all land plants, implicating the land plant-specific MIXTA MYB lineage in the early origin and evolution of the cuticle
Time is a stronger predictor of microbiome community composition than tissue in external mucosal surfaces of Atlantic salmon (Salmo salar) reared in a semi-natural freshwater environment
Open Access via the Elsevier Agreement This work was supported by the UKRI project ROBUSTSMOLT [grant numbers BBSRC BB/S004270/1 and BB/S004432/1]. There was also co-funding from the Scottish Aquaculture Innovation Centre.Peer reviewedPublisher PD
Observational constraints on the neutron star mass distribution
Radio observations of neutron star binary pulsar systems have constrained
strongly the masses of eight neutron stars. Assuming neutron star masses are
uniformly distributed between lower and upper bounds and , the
observations determine with 95\% confidence that and . These limits give observational
support to neutron star formation scenarios that suggest that masses should
fall predominantly in the range , and will also be
important in the interpretation of binary inspiral observations by the Laser
Interferometer Gravitational-wave Observatory.Comment: Postscript, 4 pages, NU-GR-
A Temporally Dynamic Gut Microbiome in Atlantic Salmon During Freshwater Recirculating Aquaculture System (RAS) Production and Post-seawater Transfer
This study was funded by the UKRI project ROBUSTSMOLT (BBSRC BB/S004270/1 and BB/S004432/1). There was also cofunding from the Scottish Aquaculture Innovation Centre. ACKNOWLEDGMENTS The authors would like to thank John Richmond and staff at MOWI and the Centre for Genome Enabled Biology and Medicine (CGEBM) at the University of Aberdeen, particularly Dr. Ewan Campbell, for help with amplification protocols, conducting 16S library preparation and sequencing. The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found below: https://www.ncbi.nlm.nih.gov/bioproject/PRJNA729215.Peer reviewedPublisher PD
A Novel Unsupervised Method to Identify Genes Important in the Anti-viral Response: Application to Interferon/Ribavirin in Hepatitis C Patients
Background: Treating hepatitis C with interferon/ribavirin results in a varied response in terms of decrease in viral titer and ultimate outcome. Marked responders have a sharp decline in viral titer within a few days of treatment initiation, whereas in other patients there is no effect on the virus (poor responders). Previous studies have shown that combination therapy modifies expression of hundreds of genes in vitro and in vivo. However, identifying which, if any, of these genes have a role in viral clearance remains challenging. Aims: The goal of this paper is to link viral levels with gene expression and thereby identify genes that may be responsible for early decrease in viral titer. Methods: Microarrays were performed on RNA isolated from PBMC of patients undergoing interferon/ribavirin therapy. Samples were collected at pre-treatment (day 0), and 1, 2, 7, 14 and 28 days after initiating treatment. A novel method was applied to identify genes that are linked to a decrease in viral titer during interferon/ribavirin treatment. The method uses the relationship between inter-patient gene expression based proximities and inter-patient viral titer based proximities to define the association between microarray gene expression measurements of each gene and viral-titer measurements. Results: We detected 36 unique genes whose expressions provide a clustering of patients that resembles viral titer based clustering of patients. These genes include IRF7, MX1, OASL and OAS2, viperin and many ISG's of unknown function. Conclusion: The genes identified by this method appear to play a major role in the reduction of hepatitis C virus during the early phase of treatment. The method has broad utility and can be used to analyze response to any group of factors influencing biological outcome such as antiviral drugs or anti-cancer agents where microarray data are available. © 2007 Brodsky et al
Binary inspiral, gravitational radiation, and cosmology
Observations of binary inspiral in a single interferometric gravitational
wave detector can be cataloged according to signal-to-noise ratio and
chirp mass . The distribution of events in a catalog composed of
observations with greater than a threshold depends on the
Hubble expansion, deceleration parameter, and cosmological constant, as well as
the distribution of component masses in binary systems and evolutionary
effects. In this paper I find general expressions, valid in any homogeneous and
isotropic cosmological model, for the distribution with and of
cataloged events; I also evaluate these distributions explicitly for relevant
matter-dominated Friedmann-Robertson-Walker models and simple models of the
neutron star mass distribution. In matter dominated Friedmann-Robertson-Walker
cosmological models advanced LIGO detectors will observe binary neutron star
inspiral events with from distances not exceeding approximately
, corresponding to redshifts of (0.26) for
(), at an estimated rate of 1 per week. As the binary system mass
increases so does the distance it can be seen, up to a limit: in a matter
dominated Einstein-deSitter cosmological model with () that limit
is approximately (1.7) for binaries consisting of two
black holes. Cosmological tests based on catalogs of the
kind discussed here depend on the distribution of cataloged events with
and . The distributions found here will play a pivotal role in testing
cosmological models against our own universe and in constructing templates for
the detection of cosmological inspiraling binary neutron stars and black holes.Comment: REVTeX, 38 pages, 9 (encapsulated) postscript figures, uses epsf.st
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