151 research outputs found
Population Biology and Interactions of Arbuscular Mycorrhizal Fungi and Their Benefits in Strawberry Cultivation
The diversity of arbuscular mycorrhizal fungi (AMF) and relative abundance among species may affect their ecological impact. Species-specific primers for qPCR quantification of Funneliformis geosporus and F.mosseae DNA were developed to quantify their relative abundance for use in studying mixed inocula in roots of strawberry under different conditions of water stress. Co-occupation of the same root by both species was shown to commonly occur but the relative abundance of the two species varied with water stress. Greater root colonisation was observed microscopically under water stress but this increased colonisation was often accompanied with decreased amounts of fungal DNA in the root. Funneliformis mosseae tended to become more abundant under water stress relative to F. geosporus. There was significant correlation in the fungal colonisation measurements from the microscopic and qPCR methods under some conditions, but the nature of this relationship varied greatly with AMF inoculum and abiotic conditions.
Water stress experiments, undertaken with strawberry (Fragaria x ananassa) show a reduction of plant development when subjected to regulated deficit irrigation (RDI) conditions. The effect on growth of AMF colonisation and relative abundance of two co-occurring species of AMF, F. geosporus and F. mosseae, were determined in cultivated strawberry under conditions of water stress. Three AMF inoculation treatments (a single treatment either of F. mosseae BEG25, F. geosporus BEG11 or a 50:50 mixed inoculation treatment of both species) were compared to un-inoculated plants. This study demonstrated that in strawberry plants, under these experimental conditions, single species inoculation treatments gave similar benefits to the host as the mixed inoculation treatment regardless of irrigation regime, suggesting colonisation was of greater importance than mycorrhizal fungal species. The addition of AMF inocula to plants, subjected to reduced irrigation of up to 40%, restored plant growth to the same or higher values as the non-mycorrhizal, fully-watered plants. The water use efficiency of plants was greater under the RDI regime and in AMF-inoculated plants, but there were no significant differences between plants inoculated with the single or combined inoculum.
The occurrence of multiple variant sequences within the rRNA genes of the AMF is now widely accepted; however the mechanisms for this are not currently clear. This work investigated the effect of different culture conditions (in vitro and in planta culture) on sequence diversity and relative abundance of a culture of Rhizophagus clarus. Next generation sequencing, using the Illumina platform, generated three major sequence variants that were the most common sequence variants in all conditions. All other sequences grouped phylogenetically about these three major sequence types along with an outgroup of less common sequence types. This study demonstrated that changes in the frequency of dominant sequence variants had occurred when AMF are maintained for two years under different culture conditions
Improvements to 232-thorium, 230-thorium, and 231-protactinium analysis in seawater arising from GEOTRACES intercalibration
The GEOTRACES program requires the analysis of large numbers of seawater samples for ^(232)Th, ^(230)Th, and ^(231)Pa. During the GEOTRACES international intercalibration exercise, we encountered unexpected difficulties with recovery and contamination of these isotopes, ^(232)Th in particular. Experiments were carried out to identify the source of these issues, leading to a more streamlined and efficient procedure. The two particular problems that we identified and corrected were (1) frits in columns supplied by Bio-Rad Laboratories caused loss of Th during column chemistry and (2) new batches of AG1-X8 resin supplied by Bio-Rad Laboratories released more than 100 pg of ^(232)Th during elution of sample. To improve yields and blanks, we implemented a series of changes including switching to Eichrom anion exchange resin (100-200 μm mesh) and Environmental Express columns. All Th and Pa samples were analyzed on a Neptune multi-collector inductively-coupled-plasma mass spectrometer (MC-ICP-MS) using peak hopping of ^(230)Th and ^(229)Th on the central SEM, with either ^(232)Th, ^(236)U (or both) used to monitor for beam intensity. We used in-house laboratory standards to check for machine reproducibility, and the GEOTRACES intercalibration standard to check for accuracy. Over a 1-y period, the 2 s.d. reproducibility on the GEOTRACES SW STD 2010-1 was 2.5% for ^(230)Th, 1.8% for ^(232)Th, and 4% for ^(231)Pa. The lessons learned during this intercalibration process will be of value to those analyzing U-Th-Pa and rare earth elements as part of the GEOTRACES program as well as those using U-series elements in other applications that require high yields and low blanks, such as geochronology
231Pa/230Th evidence for a weakened but persistent Atlantic meridional overturning circulation during Heinrich Stadial 1
The strength of Atlantic meridional overturning circulation is believed to affect the climate over glacial-interglacial and millennial timescales. The marine sedimentary ²³¹Pa/²³⁰Th ratio is a promising paleocirculation proxy, but local particle effects may bias individual reconstructions. Here we present new Atlantic sedimentary ²³¹Pa/²³⁰Th data from the Holocene, the last glacial maximum and Heinrich Stadial 1, a period of abrupt cooling ca. 17,500 years ago. We combine our results with published data from these intervals to create a spatially distributed sedimentary ²³¹Pa/²³⁰Th database. The data reveal a net ²³¹Pa deficit during each period, consistent with persistent ²³¹Pa export. In highly resolved cores, Heinrich ²³¹Pa/²³⁰Th ratios exceed glacial ratios at nearly all depths, indicating a significant reduction, although not cessation, of overturning during Heinrich Stadial 1. These results support the inference that weakened overturning was a driver of Heinrich cooling, while suggesting that abrupt climate oscillations do not necessarily require a complete shutdown of overturning
‘Hot’ vs. ‘cold’ behavioural‐cognitive styles: motivational‐dopaminergic vs. cognitive‐cholinergic processing of a Pavlovian cocaine cue in sign‐ and goal‐tracking rats
Discrete Pavlovian reward cues acquire more potent incentive motivational properties (incentive salience) in some animals (sign‐trackers; STs) compared to others (goal‐trackers; GTs). Conversely, GTs appear to be better than STs in processing more complex contextual cues, perhaps reflecting their relatively greater bias for goal‐directed cue processing. Here, we investigated the activity of two major prefrontal neuromodulatory input systems, dopamine (DA) and acetylcholine (ACh), in response to a discrete Pavlovian cue that was previously paired with cocaine administration in STs and GTs. Rats underwent Pavlovian training in which light cue presentations were either paired or unpaired with an intravenous cocaine infusion. Following a 10‐day abstinence period, prefrontal dialysates were collected in STs and GTs during cue presentations in the absence of cocaine. In STs, the cue previously paired with cocaine significantly increased prefrontal DA levels. DA levels remained elevated over baseline across multiple cue presentation blocks, and DA levels and approaches to the cue were significantly correlated. In STs, ACh levels were unaffected by cue presentations. In contrast, in GTs, presentations of the cocaine cue increased prefrontal ACh, but not DA, levels. GTs oriented towards the cue at rates similar to STs, but they did not approach it and elevated ACh levels did not correlate with conditioned orientation. The results indicate a double dissociation between the role of prefrontal DA and ACh in STs and GTs, and suggest that these phenotypes will be useful for studying the role of neuromodulator systems in mediating opponent behavioural‐cognitive styles.We investigated the activity of two major prefrontal neuromodulatory input systems, dopamine (DA) and acetylcholine (ACh), in response to a Pavlovian cue that was previously paired with cocaine administration in STs and GTs. Following an abstinence period and in the absence of cocaine, cue presentations (C1–C4) in STs resulted in increases in extracellular DA, but not ACh, levels (left). In contrast, cue presentations in GTs increased ACh, but not DA, levels (NC, no‐cue).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141035/1/ejn13741_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141035/2/ejn13741-sup-0001-reviewer_comments.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141035/3/ejn13741.pd
Effect on microbial communities in apple orchard soil when exposed short-term to climate change abiotic factors and different orchard management practices
Aim
We assessed the effect of exposing apple orchard soil to different temperatures and CO2 levels on the resident microbiome of soils from a conventionally managed and an organically managed apple orchard. The key difference between these two orchards was that synthetic fertilizers and pesticides are routinely used in the former one.
Methods and results
To investigate the effect of CO2 and temperature soil samples from each site at two depths were exposed to elevated temperature (29°C) at either 5,000 or 10,000 ppm for 5 weeks or control conditions (25°C + 400 ppm). Both bacterial and fungal communities were profiled with amplicon-sequencing. The differences between the two orchards were the most significant factor affecting bacterial and fungal communities contributing to 53.7% and 14.0% of variance in Bray-Curtis β diversity respectively. Elevated CO2 concentration and increased temperature affected organic orchard microbial diversity more than the conventionally managed orchard. A number of candidate beneficial and pathogenic microorganisms had differential abundance when temperature and CO2 were elevated, but their effect on the plant is unclear.
Conclusions
This study has highlighted that microbial communities in bulk soils are most significantly influenced by crop management practice compared to the climate conditions used in the study. The studied climate conditions had a more limited effect on microbial communitiy diversity in conventionally managed soil samples than in organically managed soils.Biotechnology and Biological Sciences Research Council (BBSRC); Collaborative Training Partnerships (CTP) for Fruit Crop Research; NIAB EM
The dose-response effect in routinely delivered psychological therapies: A systematic review
The dose-response effect refers to the relationship between the dose (e.g., length, frequency) of treatment and the subsequent probability of improvement. This systematic review aimed to synthesise the literature on the dose-response effect in routine psychological therapies delivered to adult patients with mental health problems. Twenty-six studies were eligible for inclusion. Different methodological approaches have been used to examine the dose-response effect; including survival analysis, multilevel modelling and descriptive cluster analyses. Replicated and consistent support was found for a curvilinear (log-linear or cubic) relationship between treatment length and outcomes, with few exceptions such as eating disorders and severe psychiatric populations. Optimal doses of psychotherapy in routine settings range between 4 – 26 sessions (4 – 6 for low intensity guided self-help) and vary according to setting, clinical population and outcome measures. Weekly therapy appears to accelerate the rate of improvement compared to less frequent schedules. Most of the reviewed evidence is from university counselling centres and outpatient psychotherapy clinics for common mental health problems. There is scarce and inconclusive evidence in clinical samples with chronic and severe mental disorders
Implementing the use of objective medication adherence data in routine clinical practice via the digital CFHealthHub platform: situation analysis and strategy development using the theoretical domains framework
Background
Preventative inhaled treatments preserve lung function and reduce exacerbations in cystic fibrosis (CF). Self-reported adherence to these treatments is over-estimated. An online platform (CFHealthHub) has been developed with patients and clinicians to display real-time objective adherence data from dose-counting nebulisers, so that clinical teams can offer informed treatment support.
Methods
In this paper, we identify pre-implementation barriers to healthcare practitioners performing two key behaviours: accessing objective adherence data through the website CFHealthHub and discussing medication adherence with patients. We aimed to understand barriers during the pre-implementation phase, so that appropriate strategy could be developed for the scale up of implementing objective adherence data in 19 CF centres.
Thirteen semi-structured interviews were conducted with healthcare practitioners working in three UK CF centres. Qualitative data were coded using the theoretical domains framework (TDF), which describes 14 validated domains to implementation behaviour change.
Results
Analysis indicated that an implementation strategy should address all 14 domains of the TDF to successfully support implementation. Participants did not report routines or habits for using objective adherence data in clinical care. Examples of salient barriers included skills, beliefs in consequences, and social influence and professional roles. The results also affirmed a requirement to address organisational barriers. Relevant behaviour change techniques were selected to develop implementation strategy modules using the behaviour change wheel approach to intervention development.
Conclusions
This paper demonstrates the value of applying the TDF at pre-implementation, to understand context and to support the development of a situationally relevant implementation strategy
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications
TvdF and TS acknowledge financial support for a bursary by the Grantham Institute of Climate Change and the Environment and a Marie Curie Reintegration grant (IRG 230828), as well as funding from the Leverhulme Trust (RPG-398) and the NERC (NE/N001141/1). Additional financial support was provided to LFR by the USGS-WHOI Co-operative agreement, NSF-ANT grants 0636787 and 80295700, The European Research Council, the Leverhulme Trust and a Marie Curie Reintegration grant. LB was supported by a NOAA/UCAR Climate and Global Change Postdoctoral Fellowship and KJM acknowledges funding from a Marie Curie International Outgoing fellowship (IOF 236962).Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new results on modern specimens of Desmophyllum dianthus, Balanophyllia malouinensis, and Flabellum curvatum, collected from the Drake Passage, and Madrepora oculata, collected from the North Atlantic. All modern individuals were either collected alive or uranium-series dated to be < 500 years old for comparison with local surface sediments and seawater profiles. Modern coral Nd isotopic compositions generally agree with ambient seawater values, which in turn are consistent with previously published seawater analyses, supporting small vertical and lateral Nd isotope gradients in modern Drake Passage waters. Two Balanophyllia malouinensis specimens collected live however deviate by up to 0.6 epsilon units from ambient seawater. We therefore recommend that this species should be treated with caution for the reconstruction of past seawater Nd isotopic compositions. Seventy fossil Drake Passage CWCs were furthermore analysed for their Nd concentrations, revealing a large range from 7.3 to 964.5 ng/g. Samples of the species D. dianthus and Caryophyllia spp. show minor covariation of Nd with 232Th content, utilised to monitor contaminant phases in cleaned coral aragonite. Strong covariations between Nd and Th concentrations are however observed in the species B. malouinensis and G. antarctica. In order to better constrain the source and nature of Nd in the cleaned aragonitic skeletons, a subset of sixteen corals was investigated for its rare earth element (REE) content, as well as major and trace element geochemistry. Our new data provide supporting evidence that the applied cleaning protocol efficiently removes contaminant lithogenic and ferromanganese oxyhydroxide phases. Mass balance calculations and seawater-like REE patterns rule out lithogenic and ferromanganese oxyhydroxide phases as a major contributor to elevated Nd concentrations in coral aragonite. Based on mass balance considerations, geochemical evidence, and previously published independent work by solid-state nuclear magnetic resonance (NMR) spectroscopy, we suggest authigenic phosphate phases as a significant carrier of skeletal Nd. Such a carrier phase could explain sporadic appearance of high Nd concentrations in corals and would be coupled with seawater-derived Nd isotopic compositions, lending further confidence to the application of Nd isotopes as a water mass proxy in CWCs.Publisher PDFPeer reviewe
Neodymium isotope analyses after combined extraction of actinide and lanthanide elements from seawater and deep-sea coral aragonite
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 17 (2016): 232–240, doi:10.1002/2015GC006130.Isotopes of the actinide elements protactinium (Pa), thorium (Th), and uranium (U), and the lanthanide element neodymium (Nd) are often used as complementary tracers of modern and past oceanic processes. The extraction of such elements from low abundance matrices, such as seawater and carbonate, is however labor-intensive and requires significant amounts of sample material. We here present a combined method for the extraction of Pa, Th, and Nd from 5 to 10 L seawater samples, and of U, Th, and Nd from <1 g carbonate samples. Neodymium is collected in the respective wash fractions of Pa-Th and U-Th anion exchange chromatographies. Regardless of the original sample matrix, Nd is extracted during a two-stage ion chromatography, followed by thermal ionization mass spectrometry (TIMS) analysis as NdO+. Using this combined procedure, we obtained results for Nd isotopic compositions on two GEOTRACES consensus samples from Bermuda Atlantic Time Series (BATS), which are within error identical to results for separately sampled and processed dedicated Nd samples (εNd = −9.20 ± 0.21 and −13.11 ± 0.21 for 15 and 2000 m water depths, respectively; intercalibration results from 14 laboratories: εNd = −9.19 ± 0.57 and −13.14 ± 0.57). Furthermore, Nd isotope results for an in-house coral reference material are identical within analytical uncertainty for dedicated Nd chemistry and after collection of Nd from U-Th anion exchange chromatography. Our procedure does not require major adaptations to independently used ion exchange chromatographies for U-Pa-Th and Nd, and can hence be readily implemented for a wide range of applications.Funding that
supported this work was received from
the National Science Foundation
(NSF 0752402), the Leverhulme Trust
(RPG-398), the Natural
Environmental Research Council
(NE/J021636/1 and NE/N003861/1),
the European Research Council
(278705), and the Grantham Institute
for Climate Change.2016-07-0
Feasibility study for supporting medication adherence for adults with cystic fibrosis: mixed-methods process evaluation
Objectives: To undertake a process evaluation of an adherence support intervention for people with cystic fibrosis (PWCF), to assess its feasibility and acceptability. Setting: Two UK cystic fibrosis (CF) units. Participants: Fourteen adult PWCF; three professionals delivering adherence support (‘interventionists’); five multi-disciplinary CF team members. Interventions: Nebuliser with data recording and transfer capability, linked to a software platform, and strategies to support adherence to nebulised treatments facilitated by interventionists over 5 months (± 1 month). Primary and secondary measures: Feasibility and acceptability of the intervention, assessed through semistructured interviews, questionnaires, fidelity assessments and click analytics. Results: Interventionists were complimentary about the intervention and training. Key barriers to intervention feasibility and acceptability were identified. Interventionists had difficulty finding clinic space and time in normal working hours to conduct review visits. As a result, fewer than expected intervention visits were conducted and interviews indicated this may explain low adherence in some intervention arm participants. Adherence levels appeared to be >100% for some patients, due to inaccurate prescription data, particularly in patients with complex treatment regimens. Flatlines in adherence data at the start of the study were linked to device connectivity problems. Content and delivery quality fidelity were 100% and 60%–92%, respectively, indicating that interventionists needed to focus more on intervention ‘active ingredients’ during sessions. Conclusions: The process evaluation led to 14 key changes to intervention procedures to overcome barriers to intervention success. With the identified changes, it is feasible and acceptable to support medication adherence with this intervention. Trial registration number: ISRCTN13076797; Results
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