Publications by authors named "Andrew Weightman"

79 Publications

A scoping review of design requirements for a home-based upper limb rehabilitation robot for stroke.

Top Stroke Rehabil 2021 Jul 19:1-15. Epub 2021 Jul 19.

Department of Mechanical, Aerospace and Civil Engineering, School of Engineering, University of Manchester, Manchester, UK.

Background: Home-based robotic therapy is a trend of post-stroke upper limb rehabilitation. Although home-based upper limb rehabilitation robots have been developed over several decades, no design specification has been published.

Objectives: To identify and synthesize design requirements considering user and technology needs for a home-based upper limb rehabilitation robot through a scoping review.

Method: Studies published between 1 January 2000 and 10 June 2020 in Scopus, Web of Science and PubMed database regarding design requirements for upper limb rehabilitation robots from of stroke survivors or therapists were identified and analyzed. We use 'requirement' as something that is needed or wanted. Two physiotherapists ranked the requirements identified from literature review.

Results: Nine studies were selected for review. They identified 42 requirements regarding functionality (n = 11, 26.2% of total requirements), usability (n = 16, 38.0% of total requirements), software (n = 14, 33.3% of total requirements) and safety (n = 1, 2.4% of total requirements). The main implementation barriers with respect to adherence and monitoring were space, operation, and cost.

Conclusion: This is the first research to summarize the design requirements for home-based upper limb rehabilitation robots for stroke survivors. The need for a safe, comfortable, easy to use device which can be individualized and promote specific movements and tasks emerged. The result of this paper captures the design requirements that can be used in future for the development of a design specification. It provides designers and researchers guidance about the real-world needs for home-based upper limb rehabilitation robots for stroke.
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http://dx.doi.org/10.1080/10749357.2021.1943797DOI Listing
July 2021

Impaired skeletal muscle fatigue resistance during cardiac hypertrophy is prevented by functional overload- or exercise-induced functional capillarity.

J Physiol 2021 08 12;599(15):3715-3733. Epub 2021 Jul 12.

School of Biomedical Sciences, University of Leeds, Leeds, UK.

Key Points: Capillary rarefaction is hypothesized to contribute to impaired exercise tolerance in cardiovascular disease, but it remains a poorly exploited therapeutic target for improving skeletal muscle performance. Using an abdominal aortic coarctation rat model of compensatory cardiac hypertrophy, we determine the efficacy of aerobic exercise for the prevention of, and mechanical overload for, restoration of hindlimb muscle fatigue resistance and microvascular impairment in the early stages of heart disease. Impaired muscle fatigue resistance was found after development of cardiac hypertrophy, but this impairment was prevented by low-intensity aerobic exercise and recovered after mechanical stretch due to muscle overload. Changes in muscle fatigue resistance were closely related to functional (i.e. perfused) microvascular density, independent of arterial blood flow, emphasizing the critical importance of optimal capillary diffusion for skeletal muscle function. Pro-angiogenic therapies are an important tool for improving skeletal muscle function in the incipient stages of heart disease.

Abstract: Microvascular rarefaction may contribute to declining skeletal muscle performance in cardiac and vascular diseases. It remains uncertain to what extent microvascular rarefaction occurs in the earliest stages of these conditions, if impaired blood flow is an aggravating factor and whether angiogenesis restores muscle performance. To investigate this, the effects of aerobic exercise (voluntary wheel running) and functional muscle overload on the performance, femoral blood flow (FBF) and microvascular perfusion of the extensor digitorum longus (EDL) were determined in a chronic rat model of compensatory cardiac hypertrophy (CCH, induced by surgically imposed abdominal aortic coarctation). CCH was associated with hypertension (P = 0.001 vs. Control) and increased relative heart mass (P < 0.001). Immediately upon placing the aortic band (i.e. before development of CCH), post-fatigue test FBF was reduced (P < 0.003), coinciding with attenuated fatigue resistance (P = 0.039) indicating an acute arterial perfusion constraint on muscle performance. While FBF was normalized during CCH in chronic groups (P > 0.05) fatigue resistance remained reduced (P = 0.039) and was associated with reduced (P = 0.009) functional capillarity after development of CCH without intervention, indicating a microvascular limitation to muscle performance. Normalization of functional capillarity after aerobic exercise (P = 0.065) and overload (P = 0.329) in CCH coincided with restoration to control levels of muscle fatigue resistance (P > 0.999), although overload-induced EDL hypertrophy (P = 0.027) and wheel-running velocity and duration (both P < 0.05) were attenuated after aortic banding. These data show that reductions in skeletal muscle performance during CCH can be countered by improving functional capillarity, providing a therapeutic target to improve skeletal muscle function in chronic diseases.
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http://dx.doi.org/10.1113/JP281377DOI Listing
August 2021

Investigating the Influence of Architecture and Material Composition of 3D Printed Anatomical Design Scaffolds for Large Bone Defects.

Int J Bioprint 2021 24;7(2):268. Epub 2021 Feb 24.

School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester, M13 9PL, United Kingdom.

There is a significant unmet clinical need to prevent amputations due to large bone loss injuries. We are addressing this problem by developing a novel, cost-effective osseointegrated prosthetic solution based on the use of modular pieces, bone bricks, made with biocompatible and biodegradable materials that fit together in a Lego-like way to form the prosthesis. This paper investigates the anatomical designed bone bricks with different architectures, pore size gradients, and material compositions. Polymer and polymer-composite 3D printed bone bricks are extensively morphological, mechanical, and biological characterized. Composite bone bricks were produced by mixing polycaprolactone (PCL) with different levels of hydroxyapatite (HA) and β-tri-calcium phosphate (TCP). Results allowed to establish a correlation between bone bricks architecture and material composition and bone bricks performance. Reinforced bone bricks showed improved mechanical and biological results. Best mechanical properties were obtained with PCL/TCP bone bricks with 38 double zig-zag filaments and 14 spiral-like pattern filaments, while the best biological results were obtained with PCL/HA bone bricks based on 25 double zig-zag filaments and 14 spiral-like pattern filaments.
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http://dx.doi.org/10.18063/ijb.v7i2.268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8114095PMC
February 2021

Monitoring of Dynamic Plantar Foot Temperatures in Diabetes with Personalised 3D-Printed Wearables.

Sensors (Basel) 2021 Mar 2;21(5). Epub 2021 Mar 2.

Department of Electrical and Electronic Engineering, The University of Manchester, Manchester M13 9PL, UK.

Diabetic foot ulcers (DFUs) are a life-changing complication of diabetes that can lead to amputation. There is increasing evidence that long-term management with wearables can reduce incidence and recurrence of this condition. Temperature asymmetry measurements can alert to DFU development, but measurements of dynamic information, such as rate of temperature change, are under investigated. We present a new wearable device for temperature monitoring at the foot that is personalised to account for anatomical variations at the foot. We validate this device on 13 participants with diabetes (no neuropathy) (group name D) and 12 control participants (group name C), during sitting and standing. We extract dynamic temperature parameters from four sites on each foot to compare the rate of temperature change. During sitting the time constant of temperature rise after shoe donning was significantly ( < 0.05) faster at the hallux ( = 0.032, 370.4 s (C), 279.1 s (D)) and 5th metatarsal head ( = 0.011, 481.9 s (C), 356.6 s (D)) in participants with diabetes compared to controls. No significant differences at the other sites or during standing were identified. These results suggest that temperature rise time is faster at parts of the foot in those who have developed diabetes. Elevated temperatures are known to be a risk factor of DFUs and measurement of time constants may provide information on their development. This work suggests that temperature rise time measured at the plantar surface may be an indicative biomarker for differences in soft tissue biomechanics and vascularisation during diabetes onset and progression.
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http://dx.doi.org/10.3390/s21051717DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7958320PMC
March 2021

Sensorimotor delays in tracking may be compensated by negative feedback control of motion-extrapolated position.

Exp Brain Res 2021 Jan 2;239(1):189-204. Epub 2020 Nov 2.

Division of Psychology and Mental Health, University of Manchester, Manchester, UK.

Sensorimotor delays dictate that humans act on outdated perceptual information. As a result, continuous manual tracking of an unpredictable target incurs significant response delays. However, no such delays are observed for repeating targets such as the sinusoids. Findings of this kind have led researchers to claim that the nervous system constructs predictive, probabilistic models of the world. However, a more parsimonious explanation is that visual perception of a moving target position is systematically biased by its velocity. The resultant extrapolated position could be compared with the cursor position and the difference canceled by negative feedback control, compensating sensorimotor delays. The current study tested whether a position extrapolation model fit human tracking of sinusoid (predictable) and pseudorandom (less predictable) targets better than the non-biased position control model, Twenty-eight participants tracked these targets and the two computational models were fit to the data at 60 fixed loop delay values (simulating sensorimotor delays). We observed that pseudorandom targets were tracked with a significantly greater phase delay than sinusoid targets. For sinusoid targets, the position extrapolation model simulated tracking results more accurately for loop delays longer than 120 ms, thereby confirming its ability to compensate for sensorimotor delays. However, for pseudorandom targets, this advantage arose only after 300 ms, indicating that velocity information is unlikely to be exploited in this way during the tracking of less predictable targets. We conclude that negative feedback control of position is a parsimonious model for tracking pseudorandom targets and that negative feedback control of extrapolated position is a parsimonious model for tracking sinusoidal targets.
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http://dx.doi.org/10.1007/s00221-020-05962-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884356PMC
January 2021

A systematic evaluation of the evidence for perceptual control theory in tracking studies.

Neurosci Biobehav Rev 2020 05 21;112:616-633. Epub 2020 Feb 21.

Division of Psychology and Mental Health, University of Manchester, UK. Electronic address:

Perceptual control theory (PCT) proposes that perceptual inputs are controlled to intentional 'reference' states by hierarchical negative feedback control, evidence for which comes from manual tracking experiments in humans. We reviewed these experiments to determine whether tracking is a process of perceptual control, and to assess the state-of-the-evidence for PCT. A systematic literature search was conducted of peer-review journal and book chapters in which tracking data were simulated with a PCT model (13 studies, 53 participants). We report a narrative review of these studies and a qualitative assessment of their methodological quality. We found evidence that individuals track to individual-specific endogenously-specified reference states and act against disturbances, and evidence that hierarchical PCT can simulate complex tracking. PCT's learning algorithm, reorganization, was not modelled. Limitations exist in the range of tracking conditions under which the PCT model has been tested. Future PCT research should apply the PCT methodology to identify control variables in real-world tasks and develop hierarchical PCT architectures for goal-oriented robotics to test the plausibility of PCT model-based action control.
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http://dx.doi.org/10.1016/j.neubiorev.2020.02.030DOI Listing
May 2020

A Mechanism for Statin-Induced Susceptibility to Myopathy.

JACC Basic Transl Sci 2019 Aug 26;4(4):509-523. Epub 2019 Aug 26.

School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.

This study aimed to identify a mechanism for statin-induced myopathy that explains its prevalence and selectivity for skeletal muscle, and to understand its interaction with moderate exercise. Statin-associated adverse muscle symptoms reduce adherence to statin therapy; this limits the effectiveness of statins in reducing cardiovascular risk. The issue is further compounded by perceived interactions between statin treatment and exercise. This study examined muscles from individuals taking statins and rats treated with statins for 4 weeks. In skeletal muscle, statin treatment caused dissociation of the stabilizing protein FK506 binding protein (FKBP12) from the sarcoplasmic reticulum (SR) calcium (Ca) release channel, the ryanodine receptor 1, which was associated with pro-apoptotic signaling and reactive nitrogen species/reactive oxygen species (RNS/ROS)-dependent spontaneous SR Ca release events (Ca sparks). Statin treatment had no effect on Ca spark frequency in cardiac myocytes. Despite potentially deleterious effects of statins on skeletal muscle, there was no impact on force production or SR Ca release in electrically stimulated muscle fibers. Statin-treated rats with access to a running wheel ran further than control rats; this exercise normalized FKBP12 binding to ryanodine receptor 1, preventing the increase in Ca sparks and pro-apoptotic signaling. Statin-mediated RNS/ROS-dependent destabilization of SR Ca handling has the potential to initiate skeletal (but not cardiac) myopathy in susceptible individuals. Importantly, although exercise increases RNS/ROS, it did not trigger deleterious statin effects on skeletal muscle. Indeed, our results indicate that moderate exercise might benefit individuals who take statins.
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http://dx.doi.org/10.1016/j.jacbts.2019.03.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6712048PMC
August 2019

Not all Pseudomonas aeruginosa are equal: strains from industrial sources possess uniquely large multireplicon genomes.

Microb Genom 2019 07 6;5(7). Epub 2019 Jun 6.

Microbiomes, Microbes and Informatics Group, Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, UK.

Pseudomonas aeruginosa is a highly versatile, antibiotic-resistant Gram-negative bacterium known for causing opportunistic infections and contamination of industrial products. Despite extensive genomic analysis of clinical P. aeruginosa strains, no genomes exist for preservative-tolerant industrial strains. A unique collection of 69 industrial isolates was assembled and compared to clinical and environmental strains; 16 genetically distinct industrial strains were subjected to array tube genotyping, multilocus sequence typing and whole-genome sequencing. The industrial strains possessed high preservative tolerance and were dispersed widely across P. aeruginosa as a species, but recurrence of strains from the same lineage within specific industrial products and locations was identified. The industrial P. aeruginosa genomes (mean=7.0 Mb) were significantly larger than those of previously sequenced environmental (mean=6.5 Mb; n=19) and clinical (mean=6.6 Mb; n=66) strains. Complete sequencing of the P. aeruginosa industrial strain RW109, which encoded the largest genome (7.75 Mb), revealed a multireplicon structure including a megaplasmid (555 265 bp) and large plasmid (151 612 bp). The RW109 megaplasmid represented an emerging plasmid family conserved in seven industrial and two clinical P. aeruginosa strains, and associated with extremely stress-resilient phenotypes, including antimicrobial resistance and solvent tolerance. Here, by defining the detailed phylogenomics of P. aeruginosa industrial strains, we show that they uniquely possess multireplicon, megaplasmid-bearing genomes, and significantly greater genomic content worthy of further study.
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http://dx.doi.org/10.1099/mgen.0.000276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6700666PMC
July 2019

Impact of flow hydrodynamics and pipe material properties on biofilm development within drinking water systems.

Environ Technol 2020 Dec 29;41(28):3732-3744. Epub 2019 May 29.

Microbiomes, Microbes and Informatics Group, Organisms and Environment Division, School of Biosciences, Cardiff, UK.

The aim of this study was to investigate the combined impact of flow hydrodynamics and pipe material on biofilm development in drinking water distribution systems (DWDS). Biofilms were formed on four commonly used pipe materials (namely polyvinyl chloride, polypropylene, structured wall high-density polyethylene and solid wall high-density polyethylene) within a series of purpose built flow cell reactors at two different flow regimes. Results indicate that varying amounts of microbial material with different morphologies were present depending on the pipe material and conditioning. The amount of microbial biomass was typically greater for the biofilms conditioned at lower flows. Whereas, biofilm development was inhibited at higher flows indicating shear forces imposed by flow conditions were above the critical levels for biofilm attachment. was the predominant bacterial group within the biofilms incubated at low flow and represented 48% of evaluated phylotypes; whilst at higher flows, (45%) and (33%) were the dominant groups. The opportunistic pathogens, and were found to be particularly abundant in biofilms incubated at lower flows, and only found within biofilms incubated at higher flows on the rougher materials assessed. This suggests that these bacteria have limited ability to propagate within biofilms under high shear conditions without sufficient protection (roughness). These findings expand on knowledge relating to the impact of surface roughness and flow hydrodynamics on biofilm development within DWDS.
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http://dx.doi.org/10.1080/09593330.2019.1619844DOI Listing
December 2020

Presence of Subspecies Monitored Over Varying Temporal and Spatial Scales in River Catchments: Persistent Routes for Human Exposure.

Microorganisms 2019 May 15;7(5). Epub 2019 May 15.

Biomedical and Life Sciences Division, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.

subspecies () was monitored by quantitative PCR over a range of temporal and spatial scales in the River Tywi catchment. This study shows the persistence of over a 10-year period with little change, which correlates with the recognised levels of Johne's disease in British herds over that period (aim 1). was quantified within the river at up to 10 cell equivalents L and was shown to be consistently present when monitored over finer timescales (aim 4). Small wastewater treatment plants where the ingress of human-associated might be expected had no significant effect (aim 2). was found for the first time to be located in natural river foams providing another route for spread via aerosols (aim 5). This study provides evidence for the environmental continuum of from the grazing infected animal via rain driven runoff through field drains and streams into main rivers; with detection at a high frequency throughout the year. Should need to be monitored in the future, we recommend that weekly or monthly sampling from a fixed location on a river will capture an adequate representation of the flow dynamics of in a catchment (aim 3). The human exposure to during this process and its impact on human health remains unquantified.
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http://dx.doi.org/10.3390/microorganisms7050136DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560452PMC
May 2019

Genome Sequences of Two Choline-Utilizing Methanogenic Archaea, spp., Isolated from Marine Sediments.

Microbiol Resour Announc 2019 May 2;8(18). Epub 2019 May 2.

School of Earth and Ocean Sciences, Cardiff University, Cardiff, Wales, United Kingdom.

The genomes of two spp. that were isolated from marine sediments and are capable of carrying out methanogenesis from choline and other methylotrophic substrates were sequenced. The average nucleotide identity and DNA-DNA hybridization analyses demonstrate that they represent species different from those previously described.
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http://dx.doi.org/10.1128/MRA.00342-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6498239PMC
May 2019

Uncultured Microbial Phyla Suggest Mechanisms for Multi-Thousand-Year Subsistence in Baltic Sea Sediments.

mBio 2019 04 16;10(2). Epub 2019 Apr 16.

University of Tennessee, Knoxville, Tennessee, USA

Energy-starved microbes in deep marine sediments subsist at near-zero growth for thousands of years, yet the mechanisms for their subsistence are unknown because no model strains have been cultivated from most of these groups. We investigated Baltic Sea sediments with single-cell genomics, metabolomics, metatranscriptomics, and enzyme assays to identify possible subsistence mechanisms employed by uncultured , , group OPB41, , , , , , and marine group II lineages. Some functions appeared to be shared by multiple lineages, such as trehalose production and NAD-consuming deacetylation, both of which have been shown to increase cellular life spans in other organisms by stabilizing proteins and nucleic acids, respectively. Other possible subsistence mechanisms differed between lineages, possibly providing them different physiological niches. Enzyme assays and transcripts suggested that and group OPB41 catabolized sugars, whereas and catabolized peptides. Metabolite and transcript data suggested that utilized allantoin, possibly as an energetic substrate or chemical protectant, and also possessed energy-efficient sodium pumps. single-cell amplified genomes (SAGs) recruited transcripts for full pathways for the production of all 20 canonical amino acids, and the gene for amino acid exporter YddG was one of their most highly transcribed genes, suggesting that they may benefit from metabolic interdependence with other cells. Subsistence of uncultured phyla in deep subsurface sediments may occur through shared strategies of using chemical protectants for biomolecular stabilization, but also by differentiating into physiological niches and metabolic interdependencies. Much of life on Earth exists in a very slow-growing state, with microbes from deeply buried marine sediments representing an extreme example. These environments are like natural laboratories that have run multi-thousand-year experiments that are impossible to perform in a laboratory. We borrowed some techniques that are commonly used in laboratory experiments and applied them to these natural samples to make hypotheses about how these microbes subsist for so long at low activity. We found that some methods for stabilizing proteins and nucleic acids might be used by many members of the community. We also found evidence for niche differentiation strategies, and possibly cross-feeding, suggesting that even though they are barely growing, complex ecological interactions continue to occur over ultralong timescales.
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http://dx.doi.org/10.1128/mBio.02376-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6469976PMC
April 2019

Rock-crushing derived hydrogen directly supports a methanogenic community: significance for the deep biosphere.

Environ Microbiol Rep 2019 04 26;11(2):165-172. Epub 2018 Dec 26.

School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, Cardiff, CF10 3AT, Wales, UK.

Microbial populations exist to great depths on Earth, but with apparently insufficient energy supply. Earthquake rock fracturing produces H from mechanochemical water splitting, however, microbial utilization of this widespread potential energy source has not been directly demonstrated. Here, we show experimentally that mechanochemically generated H from granite can be directly, long-term, utilized by a CH producing microbial community. This is consistent with CH formation in subsurface rock fracturing in the environment. Our results not only support water splitting H generation as a potential deep biosphere energy source, but as an oxidant must also be produced, they suggest that there is also a respiratory oxidant supply in the subsurface which is independent of photosynthesis. This may explain the widespread distribution of facultative aerobes in subsurface environments. A range of common rocks were shown to produce mechanochemical H , and hence, this process should be widespread in the subsurface, with the potential for considerable mineral fuelled CH production.
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http://dx.doi.org/10.1111/1758-2229.12723DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7379504PMC
April 2019

Highly competitive fungi manipulate bacterial communities in decomposing beech wood (Fagus sylvatica).

FEMS Microbiol Ecol 2019 02;95(2)

Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff. CF10 3AX. Wales, UK.

The bacterial communities in decomposing wood are receiving increased attention, but their interactions with wood-decay fungi are poorly understood. This is the first field study to test the hypothesis that fungi are responsible for driving bacterial communities in beech wood (Fagus sylvatica). A meta-genetic approach was used to characterise bacterial and fungal communities in wood that had been laboratory-colonised with known wood-decay fungi, and left for a year at six woodland sites. Alpha-, Beta- and Gammaproteobacteria and Acidobacteria were the proportionally dominant bacterial taxa, as in previous studies. Pre-colonising wood with decay fungi had a clear effect on the bacterial community, apparently via direct fungal influence; the bacterial and fungal communities present at the time of collection explained nearly 60% of their mutual covariance. Site was less important than fungal influence in determining bacterial communities, but the effects of pre-colonisation were more pronounced at some sites than at others. Wood pH was also a strong bacterial predictor, but was itself under considerable fungal influence. Burkholderiaceae and Acidobacteriaceae showed directional responses against the trend of the bacterial community as a whole.
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http://dx.doi.org/10.1093/femsec/fiy225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301287PMC
February 2019

Public's Willingness to Pay Towards a Medical Device for Detecting Foot Ulceration in People with Diabetes.

Appl Health Econ Health Policy 2018 Aug;16(4):559-567

School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester, UK.

Objectives: Diabetic foot ulceration (DFU) is a common and serious complication among diabetic patients. A medical device has been developed to prevent the occurrence of DFU. The aim of this study was to investigate the willingness to pay (WTP) for this device among the general public in the UK.

Methods: A contingent valuation survey was administered to 1051 participants through an online survey including questions on socio-demographic characteristics, self-reported health, knowledge of diabetes and medical devices, and WTP. A two-part model was used to analyse determinants of WTP, including a logistic model in the first part and a generalised linear model with a log-transformed WTP in the second part.

Results: More than half (55.9%) of the participants expressed a positive WTP. The annual mean (standard deviation) and median (interquartile range) WTP values were £76.9 (69.1) and £50 (80), respectively. Older age, middle-level education, good/excellent self-reported health, visiting doctors once/2-5 times, diabetes experience, medical device experience and more than average self-perceived likelihood of using similar devices were associated with a higher likelihood of willingness to pay. Younger age, male gender and higher household income were associated with higher WTP values.

Conclusion: This study demonstrated that people are willing to pay for this device and they tend to contribute when they have experience of diabetes or similar devices and perceive self-benefit.
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http://dx.doi.org/10.1007/s40258-018-0400-zDOI Listing
August 2018

Perceptual control models of pursuit manual tracking demonstrate individual specificity and parameter consistency.

Atten Percept Psychophys 2017 Nov;79(8):2523-2537

Division of Psychology and Mental Health, School of Psychological Sciences, University of Manchester, 2nd Floor Zochonis Building, Brunswick Street, Manchester, M13 9PL, UK.

Computational models that simulate individuals' movements in pursuit-tracking tasks have been used to elucidate mechanisms of human motor control. Whilst there is evidence that individuals demonstrate idiosyncratic control-tracking strategies, it remains unclear whether models can be sensitive to these idiosyncrasies. Perceptual control theory (PCT) provides a unique model architecture with an internally set reference value parameter, and can be optimized to fit an individual's tracking behavior. The current study investigated whether PCT models could show temporal stability and individual specificity over time. Twenty adults completed three blocks of 15 1-min, pursuit-tracking trials. Two blocks (training and post-training) were completed in one session and the third was completed after 1 week (follow-up). The target moved in a one-dimensional, pseudorandom pattern. PCT models were optimized to the training data using a least-mean-squares algorithm, and validated with data from post-training and follow-up. We found significant inter-individual variability (partial η: .464-.697) and intra-individual consistency (Cronbach's α: .880-.976) in parameter estimates. Polynomial regression revealed that all model parameters, including the reference value parameter, contribute to simulation accuracy. Participants' tracking performances were significantly more accurately simulated by models developed from their own tracking data than by models developed from other participants' data. We conclude that PCT models can be optimized to simulate the performance of an individual and that the test-retest reliability of individual models is a necessary criterion for evaluating computational models of human performance.
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http://dx.doi.org/10.3758/s13414-017-1398-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5662710PMC
November 2017

Piezo1 channels sense whole body physical activity to reset cardiovascular homeostasis and enhance performance.

Nat Commun 2017 08 24;8(1):350. Epub 2017 Aug 24.

Schools of Medicine, University of Leeds, Leeds, LS2 9JT, UK.

Mammalian biology adapts to physical activity but the molecular mechanisms sensing the activity remain enigmatic. Recent studies have revealed how Piezo1 protein senses mechanical force to enable vascular development. Here, we address Piezo1 in adult endothelium, the major control site in physical activity. Mice without endothelial Piezo1 lack obvious phenotype but close inspection reveals a specific effect on endothelium-dependent relaxation in mesenteric resistance artery. Strikingly, the Piezo1 is required for elevated blood pressure during whole body physical activity but not blood pressure during inactivity. Piezo1 is responsible for flow-sensitive non-inactivating non-selective cationic channels which depolarize the membrane potential. As fluid flow increases, depolarization increases to activate voltage-gated Ca channels in the adjacent vascular smooth muscle cells, causing vasoconstriction. Physical performance is compromised in mice which lack endothelial Piezo1 and there is weight loss after sustained activity. The data suggest that Piezo1 channels sense physical activity to advantageously reset vascular control.The mechanisms that regulate the body's response to exercise are poorly understood. Here, Rode et al. show that the mechanically activated cation channel Piezo1 is a molecular sensor of physical exercise in the endothelium that triggers endothelial communication to mesenteric vessel muscle cells, leading to vasoconstriction.
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http://dx.doi.org/10.1038/s41467-017-00429-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571199PMC
August 2017

Interlaboratory quantification of Bacteria and Archaea in deeply buried sediments of the Baltic Sea (IODP Expedition 347).

FEMS Microbiol Ecol 2017 03;93(3)

Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA.

Two common quantification methods for subseafloor microorganisms are catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) and quantitative PCR (qPCR). Using these methods, we quantified Bacteria and Archaea in Baltic Sea basin sediments (IODP Exp. 347) down to 90 mbsf, testing the following hypotheses in an interlaboratory comparison: (1) proteinase K permeabilization of archaeal cell walls increases CARD-FISH accuracy and (2) qPCR varies by more than an order of magnitude between laboratories using similar protocols. CARD-FISH counts did not differ between permeabilization treatments, demonstrating that proteinase K did not increase accuracy of CARD-FISH counts. However, 91% of these counts were below the quantification limit of 1.3 × 107 cells cm-3. For qPCR, data varied between laboratories, but were largely within the same order of magnitude if the same primers were used, with 88% of samples being above the quantification limit. Copy number values were elevated by preparing a sediment slurry before DNA extraction: 3.88 × 106-2.34 × 109 16S rRNA gene copies cm-3 vs. 1.39 × 107-1.87 × 109 total cells cm-3. By qPCR, Bacteria were more abundant than Archaea, although they usually were within the same order of magnitude. Overall, qPCR is more sensitive than CARD-FISH, but both require optimization to consistently achieve both precision and accuracy.
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http://dx.doi.org/10.1093/femsec/fix007DOI Listing
March 2017

Walking cadence affects rate of plantar foot temperature change but not final temperature in younger and older adults.

Gait Posture 2017 02 6;52:272-279. Epub 2016 Dec 6.

School of Healthcare Science, Manchester Metropolitan University, Manchester, M15GD, United Kingdom.

This study examined the relationship between (1) foot temperature in healthy individuals and walking cadence, (2) temperature change at different locations of the foot, and (3) temperature change and its relationship with vertical pressures exerted on the foot. Eighteen healthy adult volunteers (10 between 30 and 40 years - Age: 33.4±2.4years; 8 above 40 years - Age: 54.1±7.7years) were recruited. A custom-made insole with temperature sensors was placed directly onto the plantar surface of the foot and held in position using a sock. The foot was placed on a pressure sensor and the whole system placed in a canvas shoe. Participants visited the lab on three separate occasions when foot temperature and pressure data were recorded during walking on a treadmill at one of three cadences (80, 100, 120steps/min). The plantar foot temperature increased during walking in both age groups 30-40 years: 4.62±2.00°C, >40years: 5.49±2.30°C, with the rise inversely proportional to initial foot temperature (30-40 years: R=-0.669, >40years: R=-0.816). Foot temperature changes were not different between the two age groups or the different foot locations and did not depend on vertical pressures. Walking cadence affected the rate of change of plantar foot temperature but not the final measured value and no association between temperature change and vertical pressure was found. These results provide baseline values for comparing foot temperature changes in pathological conditions which could inform understanding of pathophysiology and support development of evidence based healthcare guidelines for managing conditions such as diabetic foot ulceration (DFU).
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http://dx.doi.org/10.1016/j.gaitpost.2016.12.008DOI Listing
February 2017

Bacteria in decomposing wood and their interactions with wood-decay fungi.

FEMS Microbiol Ecol 2016 11 23;92(11). Epub 2016 Aug 23.

Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK.

The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research.
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http://dx.doi.org/10.1093/femsec/fiw179DOI Listing
November 2016

Employing the International Classification of Functioning, Disability and Health framework to capture user feedback in the design and testing stage of development of home-based arm rehabilitation technology.

Assist Technol 2016 ;28(3):175-82

c School of Mechanical Engineering , University of Leeds , Leeds, UK.

The purpose of this study was to evaluate the International Classification of Functioning, Disability and Health (ICF) as a framework to ensure that key aspects of user feedback are identified in the design and testing stages of development of a home-based upper limb rehabilitation system. Seventeen stroke survivors with residual upper limb weakness, and seven healthcare professionals with expertise in stroke rehabilitation, were enrolled in the user-centered design process. Through semi-structured interviews, they provided feedback on the hardware, software and impact of a home-based rehabilitation device to facilitate self-managed arm exercise. Members of the multidisciplinary clinical and engineering research team, based on previous experience and existing literature in user-centred design, developed the topic list for the interviews. Meaningful concepts were extracted from participants' interviews based on existing ICF linking rules and matched to categories within the ICF Comprehensive Core Set for stroke. Most of the interview concepts (except personal factors) matched the existing ICF Comprehensive Core Set categories. Personal factors that emerged from interviews e.g. gender, age, interest, compliance, motivation, choice and convenience that might determine device usability are yet to be categorised within the ICF framework and hence could not be matched to a specific Core Set category.
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http://dx.doi.org/10.1080/10400435.2016.1140689DOI Listing
January 2018

Using task dynamics to quantify the affordances of throwing for long distance and accuracy.

J Exp Psychol Hum Percept Perform 2016 07 14;42(7):965-81. Epub 2016 Jan 14.

Division of Kinesiology and Health, University of Wyoming.

In 2 experiments, the current study explored how affordances structure throwing for long distance and accuracy. In Experiment 1, 10 expert throwers (from baseball, softball, and cricket) threw regulation tennis balls to hit a vertically oriented 4 ft × 4 ft target placed at each of 9 locations (3 distances × 3 heights). We measured their release parameters (angle, speed, and height) and showed that they scaled their throws in response to changes in the target's location. We then simulated the projectile motion of the ball and identified a continuous subspace of release parameters that produce hits to each target location. Each subspace describes the affordance of our target to be hit by a tennis ball moving in a projectile motion to the relevant location. The simulated affordance spaces showed how the release parameter combinations required for hits changed with changes in the target location. The experts tracked these changes in their performance and were successful in hitting the targets. We next tested unusual (horizontal) targets that generated correspondingly different affordance subspaces to determine whether the experts would track the affordance to generate successful hits. Do the experts perceive the affordance? They do. In Experiment 2, 5 cricketers threw to hit either vertically or horizontally oriented targets and successfully hit both, exhibiting release parameters located within the requisite affordance subspaces. We advocate a task dynamical approach to the study of affordances as properties of objects and events in the context of tasks as the future of research in this area. (PsycINFO Database Record
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http://dx.doi.org/10.1037/xhp0000199DOI Listing
July 2016

A pilot single-blind multicentre randomized controlled trial to evaluate the potential benefits of computer-assisted arm rehabilitation gaming technology on the arm function of children with spastic cerebral palsy.

Clin Rehabil 2016 Oct 13;30(10):1004-1015. Epub 2015 Sep 13.

Academic Department of Rehabilitation Medicine, University of Leeds, Leeds, UK National Demonstration Centre in Rehabilitation, Leeds Teaching Hospitals NHS Trust, Leeds, UK.

Objective: To evaluate the potential benefits of computer-assisted arm rehabilitation gaming technology on arm function of children with spastic cerebral palsy.

Design: A single-blind randomized controlled trial design. Power calculations indicated that 58 children would be required to demonstrate a clinically important difference.

Setting: Intervention was home-based; recruitment took place in regional spasticity clinics.

Participants: A total of 15 children with cerebral palsy aged five to 12 years were recruited; eight to the device group.

Interventions: Both study groups received 'usual follow-up treatment' following spasticity treatment with botulinum toxin; the intervention group also received a rehabilitation gaming device.

Main Measures: ABILHAND-kids and Canadian Occupational Performance Measure were performed by blinded assessors at baseline, six and 12 weeks.

Results: An analysis of covariance showed no group differences in mean ABILHAND-kids scores between time points. A non-parametric analysis of variance on Canadian Occupational Performance Measure scores showed a statistically significant improvement across time points (χ (2,15) = 6.778, p = 0.031), but this improvement did not reach minimal clinically important difference. Mean daily device use was seven minutes. Recruitment did not reach target owing to unanticipated staff shortages in clinical services. Feedback from children and their families indicated that the games were not sufficiently engaging to promote sufficient use that was likely to result in functional benefits.

Conclusion: This study suggests that computer-assisted arm rehabilitation gaming does not benefit arm function, but a Type II error cannot be ruled out.
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http://dx.doi.org/10.1177/0269215515604699DOI Listing
October 2016

Complex coupled metabolic and prokaryotic community responses to increasing temperatures in anaerobic marine sediments: critical temperatures and substrate changes.

FEMS Microbiol Ecol 2015 Aug 22;91(8):fiv084. Epub 2015 Jul 22.

School of Earth and Ocean Sciences, Main Building, Park Place, Cardiff University, CF10 3AT Cardiff, UK

The impact of temperature (0-80°C) on anaerobic biogeochemical processes and prokaryotic communities in marine sediments (tidal flat) was investigated in slurries for up to 100 days. Temperature had a non-linear effect on biogeochemistry and prokaryotes with rapid changes over small temperature intervals. Some activities (e.g. methanogenesis) had multiple 'windows' within a large temperature range (∼10 to 80°C). Others, including acetate oxidation, had maximum activities within a temperature zone, which varied with electron acceptor [metal oxide (up to ∼34°C) and sulphate (up to ∼50°C)]. Substrates for sulphate reduction changed from predominantly acetate below, and H2 above, a 43°C critical temperature, along with changes in activation energies and types of sulphate-reducing Bacteria. Above ∼43°C, methylamine metabolism ceased with changes in methanogen types and increased acetate concentrations (>1 mM). Abundances of uncultured Archaea, characteristic of deep marine sediments (e.g. MBGD Euryarchaeota, 'Bathyarchaeota') changed, indicating their possible metabolic activity and temperature range. Bacterial cell numbers were consistently higher than archaeal cells and both decreased above ∼15°C. Substrate addition stimulated activities, widened some activity temperature ranges (methanogenesis) and increased bacterial (×10) more than archaeal cell numbers. Hence, additional organic matter input from climate-related eutrophication may amplify the impact of temperature increases on sedimentary biogeochemistry.
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http://dx.doi.org/10.1093/femsec/fiv084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629870PMC
August 2015

Chronic effects of temperature and nitrate pollution on Daphnia magna: Is this cladoceran suitable for widespread use as a tertiary treatment?

Water Res 2015 Oct 24;83:141-52. Epub 2015 Jun 24.

School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.

Effluent clarification and disinfection are major challenges in wastewater management. The cladoceran Daphnia magna has been proposed as a cost-effective and ecosystem-friendly option to clarify and disinfect secondary effluents, but its efficacy has not been fully tested under different sewage conditions. The present study explores the effects of temperature and nitrate on the efficacy of D. magna as a tertiary treatment at two different scales (individual assays and microcosms). Individual assays were employed to determine direct effects of temperature and/or nitrate on D. magna cultured in a suspension of organic matter. Using microcosms under the same environmental conditions, we explored the clearing efficacy of D. magna interacting with a natural microbial community. Individual assays revealed that D. magna mortality increased by 17% at 26 °C, 21% at >250 mg NO3(-)/l and by 60% at 26 °C and at >250 mg NO3(-)/l, and individuals displayed reduced body size, filtering rates and fecundity when compared to those at 21 °C and <40 mg NO3(-)/l. Improved performance under these conditions was also mirrored in the microcosms, with a higher density of D. magna (>100 ind/l) at 21 °C and <40 mg NO3(-)/l compared to the number (0-21 ind/l) at 26 °C and/or >250 mg NO3(-)/l. In the microcosms at 21 °C and <40 mg NO3(-)/l, turbidity and the density of bacteria, protists and micro-metazoa decreased in relation to those at 26 °C and/or >250 mg NO3(-)/l. Each treatment developed a unique and characteristic microbial assemblage, and D. magna was identified as the major driver of the community structure of protists and micro-metazoa. This enabled us to determine taxa vulnerability to D. magna grazing, and to re-define their tolerance thresholds for nitrate. In conclusion, this study increases our knowledge of how microbes respond to temperature and nitrate pollution, and highlights that D. magna efficacy as a tertiary treatment can be seriously compromised by variable environmental conditions.
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http://dx.doi.org/10.1016/j.watres.2015.06.036DOI Listing
October 2015

Phylogeny and physiology of candidate phylum 'Atribacteria' (OP9/JS1) inferred from cultivation-independent genomics.

ISME J 2016 Feb 19;10(2):273-86. Epub 2015 Jun 19.

School of Life Science, University of Nevada, Las Vegas, NV, USA.

The 'Atribacteria' is a candidate phylum in the Bacteria recently proposed to include members of the OP9 and JS1 lineages. OP9 and JS1 are globally distributed, and in some cases abundant, in anaerobic marine sediments, geothermal environments, anaerobic digesters and reactors and petroleum reservoirs. However, the monophyly of OP9 and JS1 has been questioned and their physiology and ecology remain largely enigmatic due to a lack of cultivated representatives. Here cultivation-independent genomic approaches were used to provide a first comprehensive view of the phylogeny, conserved genomic features and metabolic potential of members of this ubiquitous candidate phylum. Previously available and heretofore unpublished OP9 and JS1 single-cell genomic data sets were used as recruitment platforms for the reconstruction of atribacterial metagenome bins from a terephthalate-degrading reactor biofilm and from the monimolimnion of meromictic Sakinaw Lake. The single-cell genomes and metagenome bins together comprise six species- to genus-level groups that represent most major lineages within OP9 and JS1. Phylogenomic analyses of these combined data sets confirmed the monophyly of the 'Atribacteria' inclusive of OP9 and JS1. Additional conserved features within the 'Atribacteria' were identified, including a gene cluster encoding putative bacterial microcompartments that may be involved in aldehyde and sugar metabolism, energy conservation and carbon storage. Comparative analysis of the metabolic potential inferred from these data sets revealed that members of the 'Atribacteria' are likely to be heterotrophic anaerobes that lack respiratory capacity, with some lineages predicted to specialize in either primary fermentation of carbohydrates or secondary fermentation of organic acids, such as propionate.
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http://dx.doi.org/10.1038/ismej.2015.97DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4737943PMC
February 2016

Archaeal community diversity and abundance changes along a natural salinity gradient in estuarine sediments.

FEMS Microbiol Ecol 2015 Feb 15;91(2):1-18. Epub 2014 Dec 15.

Cardiff School of Biosciences, Cardiff University, Main Building, Park Place, Cardiff, Wales, CF10 3AT, UK.

Archaea are widespread in marine sediments, but their occurrence and relationship with natural salinity gradients in estuarine sediments is not well understood. This study investigated the abundance and diversity of Archaea in sediments at three sites [Brightlingsea (BR), Alresford (AR) and Hythe (HY)] along the Colne Estuary, using quantitative real-time PCR (qPCR) of 16S rRNA genes, DNA hybridization, Archaea 16S rRNA and mcrA gene phylogenetic analyses. Total archaeal 16S rRNA abundance in sediments were higher in the low-salinity brackish sediments from HY (2-8 × 10(7) 16S rRNA gene copies cm(-3)) than the high-salinity marine sites from BR and AR (2 × 10(4)-2 × 10(7) and 4 × 10(6)-2 × 10(7) 16S rRNA gene copies cm(-3), respectively), although as a proportion of the total prokaryotes Archaea were higher at BR than at AR or HY. Phylogenetic analysis showed that members of the 'Bathyarchaeota' (MCG), Thaumarchaeota and methanogenic Euryarchaeota were the dominant groups of Archaea. The composition of Thaumarchaeota varied with salinity, as only 'marine' group I.1a was present in marine sediments (BR). Methanogen 16S rRNA genes from low-salinity sediments at HY were dominated by acetotrophic Methanosaeta and putatively hydrogentrophic Methanomicrobiales, whereas the marine site (BR) was dominated by mcrA genes belonging to methylotrophic Methanococcoides, versatile Methanosarcina and methanotrophic ANME-2a. Overall, the results indicate that salinity and associated factors play a role in controlling diversity and distribution of Archaea in estuarine sediments.
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http://dx.doi.org/10.1093/femsec/fiu025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4399439PMC
February 2015

Mycobacterium avium Subspecies paratuberculosis: Human Exposure through Environmental and Domestic Aerosols.

Pathogens 2014 Jul 16;3(3):577-95. Epub 2014 Jul 16.

Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK.

Mycobacterium avium subspecies paratuberculosis (Map) causes Johne's disease in animals and is significantly associated with Crohn's disease (CD) in humans. Our previous studies have shown Map to be present in U.K. rivers due to land deposition from chronic livestock infection and runoff driven by rainfall. The epidemiology of CD in Cardiff showed a significant association with the River Taff, in which Map can be detected on a regular basis. We have previously hypothesized that aerosols from the river might influence the epidemiology of CD. In this preliminary study, we detected Map by quantitative PCR in one of five aerosol samples collected above the River Taff. In addition, we examined domestic showers from different regions in the U.K. and detected Map in three out of 30 independent samples. In detecting Map in river aerosols and those from domestic showers, this is the first study to provide evidence that aerosols are an exposure route for Map to humans and may play a role in the epidemiology of CD.
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http://dx.doi.org/10.3390/pathogens3030577DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243430PMC
July 2014

The effect of anthropogenic arsenic contamination on the earthworm microbiome.

Environ Microbiol 2015 Jun 17;17(6):1884-96. Epub 2014 Dec 17.

Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK.

Earthworms are globally distributed and perform essential roles for soil health and microbial structure. We have investigated the effect of an anthropogenic contamination gradient on the bacterial community of the keystone ecological species Lumbricus rubellus through utilizing 16S rRNA pyrosequencing for the first time to establish the microbiome of the host and surrounding soil. The earthworm-associated microbiome differs from the surrounding environment which appears to be a result of both filtering and stimulation likely linked to the altered environment associated with the gut micro-habitat (neutral pH, anoxia and increased carbon substrates). We identified a core earthworm community comprising Proteobacteria (∼50%) and Actinobacteria (∼30%), with lower abundances of Bacteroidetes (∼6%) and Acidobacteria (∼3%). In addition to the known earthworm symbiont (Verminephrobacter sp.), we identified a potential host-associated Gammaproteobacteria species (Serratia sp.) that was absent from soil yet observed in most earthworms. Although a distinct bacterial community defines these earthworms, clear family- and species-level modification were observed along an arsenic and iron contamination gradient. Several taxa observed in uncontaminated control microbiomes are suppressed by metal/metalloid field exposure, including eradication of the hereto ubiquitously associated Verminephrobacter symbiont, which raises implications to its functional role in the earthworm microbiome.
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http://dx.doi.org/10.1111/1462-2920.12712DOI Listing
June 2015

Survival of Desulfotomaculum spores from estuarine sediments after serial autoclaving and high-temperature exposure.

ISME J 2015 Mar 17;9(4):922-33. Epub 2015 Mar 17.

School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, Wales, UK.

Bacterial spores are widespread in marine sediments, including those of thermophilic, sulphate-reducing bacteria, which have a high minimum growth temperature making it unlikely that they grow in situ. These Desulfotomaculum spp. are thought to be from hot environments and are distributed by ocean currents. Their cells and spores upper temperature limit for survival is unknown, as is whether they can survive repeated high-temperature exposure that might occur in hydrothermal systems. This was investigated by incubating estuarine sediments significantly above (40-80 °C) maximum in situ temperatures (∼ 23 °C), and with and without prior triple autoclaving. Sulphate reduction occurred at 40-60 °C and at 60 °C was unaffected by autoclaving. Desulfotomaculum sp. C1A60 was isolated and was most closely related to the thermophilic D. kuznetsovii(T) (∼ 96% 16S rRNA gene sequence identity). Cultures of Desulfotomaculum sp. C1A60, D. kuznetsovii(T)and D. geothermicum B2T survived triple autoclaving while other related Desulfotomaculum spp. did not, although they did survive pasteurisation. Desulfotomaculum sp. C1A60 and D. kuznetsovii cultures also survived more extreme autoclaving (C1A60, 130 °C for 15 min; D. kuznetsovii, 135 °C for 15 min, maximum of 154 °C reached) and high-temperature conditions in an oil bath (C1A60, 130° for 30 min, D. kuznetsovii 140 °C for 15 min). Desulfotomaculum sp. C1A60 with either spores or predominantly vegetative cells demonstrated that surviving triple autoclaving was due to spores. Spores also had very high culturability compared with vegetative cells (∼ 30 × higher). Combined extreme temperature survival and high culturability of some thermophilic Desulfotomaculum spp. make them very effective colonisers of hot environments, which is consistent with their presence in subsurface geothermal waters and petroleum reservoirs.
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http://dx.doi.org/10.1038/ismej.2014.190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817712PMC
March 2015
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