ORCID Profile
0000-0001-5177-8574
Current Organisations
University of Leeds Faculty of Biological Sciences
,
Sheffield Hallam University
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Publisher: Springer Science and Business Media LLC
Date: 2011
Publisher: Elsevier BV
Date: 06-2019
Abstract: Over recent years, quantification of multiple proteins in body fluids has become increasingly prominent, which is beneficial to a number of scientific fields, not least biomedical. Several techniques have been developed based on conventional ELISA one of these techniques is analysis of proteins labelled with element-tagged antibodies by ICP-MS in serum, allowing quantification of multiple targets within a single s le. This research aimed to quantify albumin and immunoglobulin G (IgG) levels in plasma, whole blood and dried blood spots using NANOGOLD
Publisher: American Chemical Society (ACS)
Date: 13-02-2007
DOI: 10.1021/BI0620961
Abstract: The Amyloid beta peptide (Abeta) of Alzheimer's diseases (AD) is closely linked to the progressive cognitive decline associated with the disease. Cu2+ ions can induce the de novo aggregation of the Abeta peptide into non-amyloidogenic aggregates and the production of a toxic species. The mechanism by which Cu2+ mediates the change from amyloid material toward Cu2+ induced aggregates is poorly defined. Here we demonstrate that the aggregation state of Abeta1-42 at neutral pH is governed by the Cu2+:peptide molar ratio. By probing amyloid content and total aggregation, we observed a distinct Cu2+ switching effect centered at equimolar Cu2+:peptide ratios. At sub-equimolar Cu2+:peptide molar ratios, Abeta1-42 forms thioflavin-T reactive amyloid conversely, at supra-equimolar Cu2+:peptide molar ratios, Abeta1-42 forms both small spherical oligomers approximately 10-20 nm in size and large amorphous aggregates. We demonstrate that these insoluble aggregates form spontaneously via a soluble species without the presence of an observable lag phase. In seeding experiments, the Cu2+ induced aggregates were unable to influence fibril formation or convert into fibrillar material. Aged Cu2+ induced aggregates are toxic when compared to Abeta1-42 aged in the absence of Cu2+. Importantly, the formation of dityrosine crosslinked Abeta, by the oxidative modification of the peptide, only occurs at equimolar molar ratios and above. The formation of dityrosine adducts occurs following the initiation of aggregation and hence does not drive the formation of the Cu2+ induced aggregates. These results define the role Cu2+ plays in modulating the aggregation state and toxicity of Abeta1-42.
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/929782
Abstract: Background. Low physical activity (PA) levels are associated with poor health risk factor profiles. Intervention strategies to increase PA and quantify the rate and magnitude of change in risk factors are important. Methods. Interventions were conducted over 40 days to increase PA in 736 insufficiently active ( min/wk PA) participants using either a pedometer or instructor-led group protocol. There were a further 135 active participants as controls. Major cardiovascular and metabolic risk factors, including fitness parameters, were measured before and after intervention. Results. Adherence to the interventions was higher for the group versus pedometer participants (87.1% versus 79.8%) and compliance rates for achieving sufficient levels of PA (≥150 min/wk) were also higher for the group participants (95.8% versus 77.6%). Total weekly PA patterns increased by 300 and 435 minutes, for the pedometer and group participants, respectively. Improvements were found for waist girth, total cholesterol, aerobic fitness, and flexibility relative to controls. The change in vigorous PA, but not moderate PA, was a significant predictor of the change in eight of 11 risk factor variables measured. Conclusions. Rapid and dramatic increases in PA among previously insufficiently active adults can result in important health benefits.
Publisher: MDPI AG
Date: 02-12-2022
Abstract: Within this study, we aim to better understand the inspirations and aspirations of first year Biosciences and Chemistry undergraduates, how these change over the first year of study and their impact on motivation and engagement. Participants were asked to write a short reflective piece at the start of Welcome Week in their first year of undergraduate study. Thematic analysis identified four themes surrounding inspirations and aspirations. The most common theme was students naming a specific career as their aspiration (58%), followed by being inspired by work experience, aspiring to undertake further study and finally personal experience of a specific illness. Our findings showed that students’ career aspirations differed depending on ethnicity, with ambitions for medicine and laboratory work showing a marked increase in some ethnically marginalised groups. Focus groups undertaken at the end of the first year of study highlight increased motivation and engagement when students feel their course content aligns with their career aims. Conversely, students are disengaged by course material they feel is irrelevant to their chosen career. Here, we will discuss the impact of these findings on creating an inclusive curriculum and the career readiness of the student body. Conclusions apply to career development modules and how the applied nature of a course can lead to engagement and higher motivation for students as well as curriculum design.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2008
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B813504E
Abstract: The separative and analytical power of ion mobility spectrometry-mass spectrometry combined with photo-induced cross-linking of site-specifically incorporated trifluoromethyldiazirine provides a powerful approach towards structural characterisation of amyloid fibrils.
Publisher: CSIRO Publishing
Date: 14-07-2023
DOI: 10.1071/MA23036
Publisher: Public Library of Science (PLoS)
Date: 14-07-2015
Publisher: Editorial Universitat Politécnica de Valéncia
Date: 14-06-2022
Publisher: Elsevier BV
Date: 10-2001
Publisher: Public Library of Science (PLoS)
Date: 13-02-2015
Publisher: American Institute of Mathematical Sciences (AIMS)
Date: 2017
Publisher: Public Library of Science (PLoS)
Date: 26-09-2012
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1016/S0022-2836(03)00688-0
Abstract: Beta 2-microglobulin (beta(2)m) is known to form amyloid fibrils de novo in vitro under acidic conditions (below pH 4.8). Fibril formation at neutral pH, however, has only been observed by deletion of the N-terminal six residues by the addition of pre-assembled seeds or in the presence of Cu(2+). Based on these observations, and other structural data, models for fibril formation of beta(2)m have been proposed that involve the fraying of the N and C-terminal beta-strands and the consequent loss of edge strand protective features. Here, we examine the role of the N and C-terminal strands in the initiation of fibrillogenesis of beta(2)m by creating point mutations in strands A and G and comparing the properties of the resulting proteins with variants containing similar mutations elsewhere in the protein. We show that truncation of buried hydrophobic side-chains in strands A and G promotes rapid fibril formation at neutral pH, even in unseeded reactions, and increases the rate of fibril formation under acidic conditions. By contrast, similar mutations created in the remaining seven beta-strands of the native protein have little effect on the rate or pH dependence of fibril formation. The data are consistent with the view that perturbation of the N and C-terminal edge strands is an important feature in the generation of assembly-competent states of beta(2)m.
Publisher: Portland Press Ltd.
Date: 25-09-2020
DOI: 10.1042/EBC20190042
Abstract: Structural biology is the study of the molecular arrangement and dynamics of biological macromolecules, particularly proteins. The resulting structures are then used to help explain how proteins function. This article gives the reader an insight into protein structure and the underlying chemistry and physics that is used to uncover protein structure. We start with the chemistry of amino acids and how they interact within, and between proteins, we also explore the four levels of protein structure and how proteins fold into discrete domains. We consider the thermodynamics of protein folding and why proteins misfold. We look at protein dynamics and how proteins can take on a range of conformations and states. In the second part of this review, we describe the variety of methods biochemists use to uncover the structure and properties of proteins that were described in the first part. Protein structural biology is a relatively new and exciting field that promises to provide atomic-level detail to more and more of the molecules that are fundamental to life processes.
Publisher: Informa UK Limited
Date: 11-2012
DOI: 10.2147/OAJSM.S37065
Publisher: MDPI AG
Date: 24-03-2021
DOI: 10.3390/CHEMOSENSORS9040059
Abstract: This paper reports on a feasibility study of electrochemical in-vitro detection of prostate cancer biomarker PCA3 (prostate cancer antigen 3) in direct assay with specific RNA aptamer labelled with a redox group (ferrocene) and immobilized on a screen-printed gold electrode surface. The cyclic voltammograms and electrochemical impedance spectroscopy methods yield encouraging results on the detection of PCA3 in a range of concentrations from 1 μg/mL down to 0.1 ng/mL in buffer solutions. Both anodic and cathodic current values in cyclic voltammograms measurements and charge transfer resistance values in electrochemical impedance spectroscopy experiments correlate with the PCA3 concentration in the s le. Kinetics studies of the binding of the PCA3 to our aptamer demonstrated high specificity of the reaction with a characteristic affinity constant of approximately 4·10−10 molar. The results of this work provide a background for the future development of novel, highly sensitive and cost-effective diagnostic methodologies for prostate cancer detection.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2017
Publisher: MDPI AG
Date: 29-01-2202
DOI: 10.3390/ENG4010022
Abstract: In the quest for the development of accurate, reliable, and cost-effective biosensing technology for early diagnostics of prostate cancer, we describe here an electrochemical biosensor combining a simple transducing method of differential pulse voltammetry (DPV) with an RNA-based aptamer labelled with a methylene blue redox group acting as a highly specific bioreceptor to the prostate cancer biomarker PCA3. A series of DPV measurements on screen-printed gold electrodes is functionalised with a redox-labelled aptamer in solutions (either buffer or synthetic urine) containing PCA3 in a wide range of concentrations from 0.1 picomolar (pM) to 10 nanomolar (nM). In these measurements, the current peak values correlate with the concentration of PCA3 and yield a low detection limit (LDL) of 0.1 pM. Furthermore, the binding kinetics study revealed the high affinity of the aptamer to the target PCA3 with the affinity constants KD of about 3.0 × 10−8 molar. In addition, the AFM study showed the increase in the molecular layer roughness caused by the binding of PCA3, which is a large RNA molecular fragment.
Publisher: Wiley
Date: 09-2001
DOI: 10.1110/PS.4901
Abstract: The aggregation of beta(2)-microglobulin (beta(2)m) into amyloid fibrils occurs in the condition known as dialysis-related amyloidosis (DRA). The protein has a beta-sandwich fold typical of the immunoglobulin family, which is stabilized by a highly conserved disulphide bond linking Cys25 and Cys80. Oxidized beta(2)m forms amyloid fibrils rapidly in vitro at acidic pH and high ionic strength. Here we investigate the role of the single disulphide bond of beta(2)m in amyloidosis in vitro. We show that reduction of the disulphide bond destabilizes the native protein such that non-native molecules are populated at neutral pH. These species are prone to oligomerization but do not form amyloid fibrils when incubated for up to 8 mo at pH 7.0 in 0.4 M NaCl. Over the pH range 4.0-1.5 in the presence of 0.4 M NaCl, however, amyloid fibrils of reduced beta(2)m are formed. These fibrils are approximately 10 nm wide, but are shorter and assemble more rapidly than those produced from the oxidized protein. These data show that population of non-native conformers of beta(2)m at neutral pH by reduction of its single disulphide bond is not sufficient for amyloid formation. Instead, association of one or more specific partially unfolded molecules formed at acid pH are necessary for the formation of beta(2)m amyloid in vitro. Further experiments will now be needed to determine the role of different oligomeric species of beta(2)m in the toxicity of the protein in vivo.
Publisher: Proceedings of the National Academy of Sciences
Date: 29-03-2010
Abstract: The key to understanding amyloid disease is the characterization of oligomeric species formed during the early stages of fibril assembly. Here we have used electrospray ionisation-ion mobility spectrometry-mass spectrometry to identify and structurally characterize the oligomers formed during amyloid assembly from β 2 -microglobulin ( β 2 m). β 2 m oligomers are shown to have collision cross-sections consistent with monomeric units arranged in elongated assemblies prior to fibril formation. Direct observation, separation, and quantification of transient oligomeric species reveals that monomers to tetramers are populated through the lag phase with no evidence for the significant population of larger oligomeric species under the conditions employed. The dynamics of each oligomeric species were monitored directly within the ensemble at concentrations commensurate with amyloid formation by observing the subunit exchange of 14 N- and 15 N- labeled oligomers. Analysis of the data revealed a decrease in oligomer dynamics concomitant with increasing oligomer size and the copopulation of dynamic dimeric and trimeric species with more stable trimeric and tetrameric species. The results presented map the events occurring during the lag phase of fibril formation and give a clear insight into the structural characteristics and dynamic nature of the β 2 m oligomers, demonstrating the existence of elongated assemblies arising from an intact amyloidogenic protein during fibril formation.
Publisher: Elsevier BV
Date: 12-2010
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1016/S0022-2836(03)00583-7
Abstract: The kinetics of spontaneous assembly of amyloid fibrils of wild-type beta(2)-microglobulin (beta(2)M) in vitro, under acid conditions (pH 2.5) and low ionic strength, has been followed using thioflavin-T (ThT) binding. In parallel experiments, the morphology of the different fibrillar species present at different time-points during the growth process were characterised using tapping-mode atomic force microscopy (TM-AFM) in air and negative stain electron microscopy (EM). The thioflavin-T assay shows a characteristic lag phase during which the nucleation of fibrils occurs before a rapid growth in fibril density. The volume of fibrils deposited on mica measured from TM-AFM images at each time-point correlates well with the fluorescence data. TM-AFM and negative-stain EM revealed the presence of various kinds of protein aggregates in the lag phase that disappear concomitantly with a rise in the density of amyloid fibrils, suggesting that these aggregates precede fibril growth and may act as nucleation sites. Three distinct morphologies of mature amyloid fibrils were observed within a single growth experiment, as observed previously for the wild-type protein and the variant N17D. Additional supercoiled morphologies of the lower-order fibrils were observed. Comparative height analysis from the TM-AFM data allows each of the mature fibril types and single protofilaments to be identified unambiguously, and reveals that the assembly occurs via a hierarchy of morphological states.
Publisher: Australian Institute of Health and Welfare
Date: 2010
Publisher: Human Kinetics
Date: 02-2019
Publisher: Portland Press Ltd.
Date: 04-2022
DOI: 10.1042/EBC20210055
Abstract: Blended learning is becoming the expected norm for core content delivery in many institutions. Pre-recorded videos in the form of screencasts are the primary delivery method, with students being asked to engage with the content in this medium. Usage is only likely to increase into the future as delivery moves away from traditional lectures and seminars. In this perspective, we look at the use of video material as a means of content delivery and how to help students engage with it. Theoretical literature around cognitive loading and active learning, alongside personal experience of delivery, is drawn on to give a framework for creating engaging recordings and learning activities.
Publisher: SAGE Publications
Date: 2019
Abstract: There are no agreed comprehensive tests for age-related changes to physical, emotional, mental and social functioning. Research into declining function focuses on those 75 years and older and little is known about age-related changes in younger people. The aims of this project were (1) to ascertain a comprehensive test battery that could underpin community-based health screening programmes for people aged 40–75 years and pilot both (2) community-based recruitment and (3) the utility, acceptability, response burden and logistics. A total of 11 databases were searched using a broad range of relevant terms. An identified comprehensive, recent, high-quality systematic review of screening instruments for detection of early functional decline for community-dwelling older people identified many relevant tools however, not all body systems were addressed. Therefore, lower hierarchy papers identified in the rapid review were included and expert panel consultation was conducted before the final test battery was agreed. Broad networks were developed in one Australian city to aid pilot recruitment of community-dwellers 40–75 years. Recruitment and testing processes were validated using feasibility testing with 12 volunteers. The test battery captured (1) online self-reports of demographics, health status, sleep quality, distress, diet, physical activity, oral health, frailty and continence and (2) objective tests of anthropometry mobility lung function dexterity flexibility, strength and stability hearing balance cognition and memory foot sensation and reaction time. Recruitment and testing processes were found to be feasible. This screening approach may provide new knowledge on healthy ageing in younger people.
Publisher: Proceedings of the National Academy of Sciences
Date: 13-05-2008
Abstract: Amelyoid-β peptide (Aβ) is a major causative agent responsible for Alzheimer's disease (AD). Aβ contains a high affinity metal binding site that modulates peptide aggregation and toxicity. Therefore, identifying molecules targeting this site represents a valid therapeutic strategy. To test this hypothesis, a range of L-PtCl 2 (L = 1,10-phenanthroline derivatives) complexes were examined and shown to bind to Aβ, inhibit neurotoxicity and rescue Aβ-induced synaptotoxicity in mouse hippoc al slices. Coordination of the complexes to Aβ altered the chemical properties of the peptide inhibiting amyloid formation and the generation of reactive oxygen species. In comparison, the classic anticancer drug cisplatin did not affect any of the biochemical and cellular effects of Aβ. This implies that the planar aromatic 1,10-phenanthroline ligands L confer some specificity for Aβ onto the platinum complexes. The potent effect of the L-PtCl 2 complexes identifies this class of compounds as therapeutic agents for AD.
Publisher: Portland Press Ltd.
Date: 10-2018
DOI: 10.1042/BIO04005022
Abstract: Electronic or e-portfolios act to bring the products or objects of learning and experience together in a digital format. They make visible the accumulation of learning, competencies and experience. The outputs can be shared with employers, accreditors and tutors alike. Used to their full potential they act as an area for focused reflection and future goal setting. In this article we will explore what an e-portfolio can be, what it can contain and how to create one.
Publisher: American Chemical Society (ACS)
Date: 12-2007
Publisher: Portland Press Ltd.
Date: 16-09-2022
DOI: 10.1042/BST20220204
Abstract: Parkinson's disease (PD) is a common neurodegenerative condition affecting a significant number of in iduals globally, resulting in the presentation of debilitating motor and non-motor symptoms, including bradykinesia, resting tremor, as well as mood and sleep disorders. The pathology of PD has been observed to spread through the central nervous system resulting in progressive brain degeneration and a poor prognosis. Aggregated forms of the protein α-synuclein, particularly intermediary aggregates, referred to as oligomers, or preformed fibrils, have been implicated as the causative agent in the degeneration of neuronal processes, including the dysfunction of axonal transport, mitochondrial activity, and ultimately cellular death. Extracellular vesicles (EVs) have been strongly implicated in the propagation of PD pathology. Current observations suggest that aggregated α-synuclein is transported between neurons via small EVs in a series of exocytosis and endocytosis cellular processes leading to the observed spread of neurotoxicity and cellular death. Despite some understanding of the role of EVs in neurodegeneration, the exact mechanism by which these lipidic particles participate in the progression of Parkinson's pathology is not entirely understood. Here we review the current understanding of the role of EVs in the propagation of PD and explore their potential as a therapeutic target.
Publisher: F1000 Research Ltd
Date: 03-06-2016
DOI: 10.12688/F1000RESEARCH.7632.2
Abstract: The ability to conceptualize 3D shapes is central to understanding biological processes. The concept that the structure of a biological molecule leads to function is a core principle of the biochemical field. Visualisation of biological molecules often involves vocal explanations or the use of two dimensional slides and video presentations. A deeper understanding of these molecules can however be obtained by the handling of objects. 3D printed biological molecules can be used as active learning tools to stimulate engagement in large group lectures. These models can be used to build upon initial core knowledge which can be delivered in either a flipped form or a more didactic manner. Within the teaching session the students are able to learn by handling, rotating and viewing the objects to gain an appreciation, for ex le, of an enzyme’s active site or the difference between the major and minor groove of DNA. Models and other artefacts can be handled in small groups within a lecture theatre and act as a focal point to generate conversation. Through the approach presented here core knowledge is first established and then supplemented with high level problem solving through a "Think-Pair-Share" cooperative learning strategy. The teaching delivery was adjusted based around experiential learning activities by moving the object from mental cognition and into the physical environment. This approach led to students being able to better visualise biological molecules and a positive engagement in the lecture. The use of objects in teaching allows the lecturer to create interactive sessions that both challenge and enable the student.
Publisher: Public Library of Science (PLoS)
Date: 29-03-2012
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 04-2018
Publisher: American Chemical Society (ACS)
Date: 29-07-2020
Publisher: The Company of Biologists
Date: 2019
DOI: 10.1242/DMM.038042
Abstract: Extensive loss of dopaminergic neurons, and aggregation of the protein α-synuclein into ubiquitin-positive Lewy bodies represents a major neuropathological hallmark of Parkinson's disease. At present the generation of large nuclear-associated Lewy bodies from endogenous wild-type α-synuclein, translationally regulated under its own promoter in human cell culture models requires costly and time-consuming protocols. Here, we demonstrate that fully differentiated human SH-SY5Y neuroblastoma cells grown in three-dimensional cell culture develop Lewy body-like pathology upon exposure to exogenous α-synuclein species. In contrast to most cell- and rodent-based models that exhibit multiple diffuse α-synuclein aggregates throughout the cytoplasm, a single large nuclear inclusion immuno-positive for α-synuclein and ubiquitin is rapidly obtained in our model. This was achieved, without the need for over-expression of α-synuclein or genetic modification of the cell line. However, phosphorylation of α-synuclein within these inclusions was not observed. The system described here provides an ideal tool to screen compounds to therapeutically intervene in Lewy body formation and to investigate the mechanisms involved in disease progression in synucleinopathies.
Publisher: Wiley
Date: 06-2016
Publisher: SAGE Publications
Date: 04-2009
DOI: 10.1255/EJMS.947
Abstract: Detailed knowledge of the tertiary and quaternary structure of proteins and protein complexes is of immense importance in understanding their functionality. Similarly, variations in the conformational states of proteins form the underlying mechanisms behind many biomolecular processes, numerous of which are disease-related. Thus, the availability of reliable and accurate biophysical techniques that can provide detailed information concerning these issues is of paramount importance. Ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) offers a unique opportunity to separate multi-component biomolecular entities and to measure the molecular mass and collision cross-section of in idual components in a single, rapid (≤ 2 min) experiment, providing 3D-architectural information directly. Here we report a method of calibrating a commercially available electrospray ionisation (ESI)-travelling wave ion mobility spectrometry (TWIMS)–mass spectrometer using known cross-sectional areas determined for a range of biomolecules by conventional IMS-MS. Using this method of calibration, we have analysed a range of proteins of differing mass and 3D architecture in their native conformations by ESI-TWIMS-MS and found that the cross-sectional areas measured in this way compare extremely favourably with cross-sectional areas calculated using an in-house computing method based on Protein Data Bank NMR-derived co-ordinates. This not only provides a high degree of confidence in the calibration method, but also suggests that the gas phase ESI-TWIMS-MS measurements relate well to solution-based measurements derived from other biophysical techniques. In order to determine which instrumental parameters affect the ESI-TWIMS-MS cross-sectional area calibration, a systematic study of the parameters used to optimise TWIMS drift time separations has been carried out, observing the effect each parameter has on drift times and IMS resolution. Finally, the ESI-TWIMS-MS cross-sectional area calibration has been applied to the analysis of the amyloidogenic protein β 2 -microglobulin and measurements for three co-populated conformational families, present under denaturing conditions, have been made: the folded, partially unfolded and unfolded states.
Publisher: Universitat Politècnica València
Date: 20-06-2018
Abstract: The Exercise Science Toolkit is a web-based educational software program for exercise and health science tertiary students and professionals. The software was developed to facilitate student engagement with essential knowledge, skills and protocols in these disciplines, provide opportunities to conduct analyses on empirical data or simulations on an unlimited supply of virtual clients including difficult or rare cases, encourage overlearning opportunities at their own pace and in their own time, and shift the emphasis from passive knowledge delivery to creative acquisition and application of knowledge. The toolkit is evidence-based with numerous databases on age- and sex-specific population norms built from systematic searches. It uses established internationally accepted protocols for the analytical tools and test procedures. The toolkit has over 40 screens or tools to engage users in a variety of pedagogical modes including pre-class preparation, laboratories in real time, in idual and group problem-based learning, online and distance education.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2008
Publisher: Proceedings of the National Academy of Sciences
Date: 15-07-2002
Abstract: Dissociation of human β-2-microglobulin (β 2 m) from the heavy chain of the class I HLA complex is a critical first step in the formation of amyloid fibrils from this protein. As a consequence of renal failure, the concentration of circulating monomeric β 2 m increases, ultimately leading to deposition of the protein into amyloid fibrils and development of the disorder, dialysis-related amyloidosis. Here we present the crystal structure of a monomeric form of human β 2 m determined at 1.8-Å resolution that reveals remarkable structural changes relative to the HLA-bound protein. These involve the restructuring of a β bulge that separates two short β strands to form a new six-residue β strand at one edge of this β sandwich protein. These structural changes remove key features proposed to have evolved to protect β sheet proteins from aggregation [Richardson, J. & Richardson, D. (2002) Proc. Natl. Acad. Sci. USA 99, 2754–2759] and replaces them with an aggregation-competent surface. In combination with solution studies using 1 H NMR, we show that the crystal structure presented here represents a rare species in solution that could provide important clues about the mechanism of amyloid formation from the normally highly soluble native protein.
Publisher: Elsevier BV
Date: 09-2011
Publisher: Routledge
Date: 03-09-2018
Publisher: Society for Neuroscience
Date: 26-09-2007
DOI: 10.1523/JNEUROSCI.0630-07.2007
Abstract: Dementia with Lewy bodies (DLB) is pathologically characterized by the presence of α-synuclein-containing Lewy bodies within the neocortical, limbic, and paralimbic regions. Like Alzheimer's disease (AD), Aβ plaques are also present in most DLB cases. The contribution of Aβ to the development of DLB is unclear. [ 11 C]-Pittsburgh compound B ([ 11 C]-PIB) is a thioflavin-T derivative that has allowed in vivo Aβ burden to be quantified using positron emission tomography (PET). [ 11 C]-PIB PET studies have shown similar high cortical [ 11 C]-PIB binding in AD and DLB subjects. To establish the potential binding of PIB to α-synuclein in DLB patients, we characterized the in vitro binding of PIB to recombinant human α-synuclein and DLB brain homogenates. Analysis of the in vitro binding studies indicated that [ 3 H]-PIB binds to α-synuclein fibrils but with lower affinity than that demonstrated/reported for Aβ 1–42 fibrils. Furthermore, [ 3 H]-PIB was observed to bind to Aβ plaque-containing DLB brain homogenates but failed to bind to DLB homogenates that were Aβ plaque-free (“pure DLB”). Positive PIB fluorescence staining of DLB brain sections colocalized with immunoreactive Aβ plaques but failed to stain Lewy bodies. Moreover, image quantification analysis suggested that given the small size and low density of Lewy bodies within the brains of DLB subjects, any contribution of Lewy bodies to the [ 11 C]-PIB PET signal would be negligible. These studies indicate that PIB retention observed within the cortical gray matter regions of DLB subjects in [ 11 C]-PIB PET studies is largely attributable to PIB binding to Aβ plaques and not Lewy bodies.
Publisher: Wiley
Date: 07-06-2020
Abstract: Within the present study, we investigate the lasting effect of laboratory peer group interactions on the end of year attainment of Biosciences and Chemistry students. By asking students to identify who they primarily work with within the laboratory environment and evaluating the interactions through cluster analysis, we identified two main categories of laboratory peer groups: the first long‐lived well‐established pairings of two students, ‘swans’, who work together for all or the majority of the laboratory sessions and the second dynamic fluid groups, ‘dolphins’, of between three and nine students who work with each other interchangeably. Statistical analysis is presented, which demonstrates that in iduals within each laboratory peer group were likely to achieve a similar average mark at the end of the first year of study on the course. We identified the driving factors for the formation of these groups as friendship and perceived work ethic. There is a preference for high‐achieving students to work with other high‐achieving students and lower‐achieving to group around a shared social background. Targeted interventions, in which pairings were selected by the tutor at the onset of the study, altered the ratio from long‐lived pairs to more dynamic groups and increased students’ willingness to work with others outside of their group but did not change the drivers of group formation or resulting pattern of achievement. We conclude with recommendations around group working within the laboratory environment.
Publisher: American Chemical Society (ACS)
Date: 18-08-2016
DOI: 10.1021/ACS.BIOCHEM.6B00708
Abstract: The Parkinson's disease-associated protein α-synuclein exhibits significant conformational heterogeneity. Bacterially expressed α-synuclein is known to bind to copper, resulting in the formation of aggregation-prone compact conformations. However, in vivo, α-synuclein undergoes acetylation at its N-terminus. Here the effect of this modification and the pathological H50Q mutation on copper binding and subsequent conformational transitions were investigated by electrospray ionization-ion mobility spectrometry-mass spectrometry. We demonstrate that acetylation perturbs the ability of α-synuclein to bind copper and that the H50Q missense mutation in the presence of N-terminal acetylation prevents copper binding. These modifications and mutations prevent the formation of the most compact conformations and inhibit copper-induced aggregation.
Publisher: Elsevier BV
Date: 09-2020
Publisher: MDPI AG
Date: 31-05-2023
Abstract: Osteosarcoma (OS) is the most common primary bone malignancy and largely effects adolescents and young adults, with 60% of patients under the age of 25. There are multiple cell models of OS described in vitro that express the specific genetic alterations of the sarcoma. In the work reported here, multiple mass spectrometry imaging (MSI) modalities were employed to characterise two aggregated cellular models of OS models formed using the MG63 and SAOS-2 cell lines. Phenotyping of the metabolite activity within the two OS aggregoid models was achieved and a comparison of the metabolite data with OS human tissue s les revealed relevant fatty acid and phospholipid markers. Although, annotations of these species require MS/MS analysis for confident identification of the metabolites. From the putative assignments however, it was suggested that the MG63 aggregoids are an aggressive tumour model that exhibited metastatic-like potential. Alternatively, the SAOS-2 aggregoids are more mature osteoblast-like phenotype that expressed characteristics of cellular differentiation and bone development. It was determined the two OS aggregoid models shared similarities of metabolic behaviour with different regions of OS human tissues, specifically of the higher metastatic grade.
Publisher: American Chemical Society (ACS)
Date: 08-01-2008
DOI: 10.1021/BI701522M
Abstract: The alpha-synuclein (alpha-syn) protein is clearly implicated in Parkinson's disease (PD). Mutations or triplication of the alpha-syn gene leads to early onset PD, possibly by accelerating alpha-syn oligomerization. alpha-syn interacts with lipids, and this membrane binding activity may relate to its toxic activity. To understand how the alpha-syn aggregation state affects its lipid binding activity we used surface plasmon resonance to study the interaction of wild-type and mutant alpha-syn with a charged phospholipid membrane, as a function of its aggregation state. Apparent dissociation constants for alpha-syn indicated that an intermediate species, present during the lag phase of amyloid formation, binds with an increased affinity to the membrane surface. Formation of this species was dependent upon the rate of fibril formation. Fluorescence anisotropy studies indicate that only upon the formation of amyloid material can alpha-syn perturb the acyl-chain region of the lipid bilayer. Circular dichroism spectroscopy showed that upon aging, both wild-type and mutant alpha-syn lose their ability to form lipid-bound alpha-helical species once they become fibrillar. These results indicate that alpha-syn forms a high affinity lipid binding intermediate species during fibril formation. Oligomeric alpha-syn is known to be toxic, and it is feasible that the high affinity binding species described here may correspond to a toxic species involved in PD.
Publisher: Elsevier BV
Date: 04-2008
Publisher: Cold Spring Harbor Laboratory
Date: 26-12-2018
DOI: 10.1101/506386
Abstract: The ision of amyloid protein fibrils is required for the propagation of the amyloid state, and is an important contributor to their stability, pathogenicity and normal function. Here, we combine kinetic nano-scale imaging experiments with analysis of a mathematical model to resolve and compare the ision stability of amyloid fibrils. Our theoretical results show that the ision of any type of filament is uniquely described by a set of three characteristic properties, resulting in convergence to self-similar length distributions distinct to each fibril type and conditions applied. By applying these results to profile the dynamical stability towards breakage for four different amyloid types, we reveal particular differences in the ision properties of disease-related amyloid formed from alpha-synuclein compared with non-disease associated model amyloid, the former showing lowered intrinsic stability towards breakage and increased likelihood of shedding smaller particles. Our results enable the comparison of protein filaments’ intrinsic dynamic stabilities, which are key to unravelling their toxic and infectious potentials.
Publisher: Wiley
Date: 10-2013
DOI: 10.1002/RCM.6693
Abstract: Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) provides a methodology to map the distribution of peptides generated by in situ tryptic digestion of biological tissue. It is challenging to correlate these peptides to the proteins from which they arise because of the many potentially overlapping and hence interfering peptide signals generated. A recombinant protein has been synthesised that when cleaved with trypsin yields a range of peptide standards for use as identification and quantification markers for multiple proteins in one MALDI-IMS-MSI experiment. Mass spectrometry images of the distribution of proteins in fresh frozen and formalin-fixed paraffin-embedded tissue s les following in situ tryptic digestion were generated by isolating signals on the basis of their m/z value and ion mobility drift time, which were correlated to matching peptides in the recombinant standard. Tryptic digestion of the IMS-TAG protein and MALDI-MS analysis yielded m/z values and ion mobility drift time for the signature peptides included in it. MALDI-IMS-MSI images for the distribution of the proteins HSP90 and vimentin, in FFPE EMT6 mouse tumours, and HSP90 and plectin in a fresh frozen mouse fibrosarcoma, were generated by extracting ion images at the corresponding m/z value and drift time from the tissue s les. The IMS-TAG approach provides a new means to confirm the identity of peptides generated by in situ digestion of biological tissue.
Publisher: American Chemical Society (ACS)
Date: 02-07-2013
Publisher: Springer Science and Business Media LLC
Date: 20-02-2020
DOI: 10.1007/S00204-020-02672-Y
Abstract: Ubiquitin proteasome system (UPS) impairment, excessive cellular oxidative stress, and iron dyshomeostasis are key to substantia nigra dopaminergic neuronal degeneration in Parkinson's disease (PD) however, a link between these features remains unconfirmed. Using the proteasome inhibitor lactacystin we confirm that nigral injury via UPS impairment disrupts iron homeostasis, in turn increasing oxidative stress and promoting protein aggregation. We demonstrate the neuroprotective potential of two novel 1-hydroxy-2(1H)-pyridinone (1,2-HOPO) iron chelators, compounds C6 and C9, against lactacystin-induced cell death. We demonstrate that this cellular preservation relates to the compounds’ iron chelating capabilities and subsequent reduced capacity of iron to form reactive oxygen species (ROS), where we also show that the ligands act as antioxidant agents. Our results also demonstrate the ability of C6 and C9 to reduce intracellular lactacystin-induced α-synuclein burden. Stability constant measurements confirmed a high affinity of C6 and C9 for Fe 3+ and display a 3:1 HOPO:Fe 3+ complex formation at physiological pH. Reducing iron reactivity could prevent the demise of nigral dopaminergic neurons. We provide evidence that the lactacystin model presents with several neuropathological hallmarks of PD related to iron dyshomeostasis and that the novel chelating compounds C6 and C9 can protect against lactacystin-related neurotoxicity.
Publisher: Portland Press Ltd.
Date: 20-03-2023
DOI: 10.1042/BIO_2023_110
Abstract: Katharine and David have won number of awards for excellence in teaching practice, from the Royal Society of Biology (RSB) Higher Education Teacher of the year award to National Teaching Fellowships. They are co-founders of the RSB Bioscience Educator Network, which provides support and mentoring to education-focused colleagues working in UK Bioscience.
Publisher: Elsevier BV
Date: 09-2010
Publisher: Wiley
Date: 09-06-2005
Abstract: Dopamine (DA) and alpha-synuclein (alpha-SN) are two key molecules associated with Parkinson's disease (PD). We have identified a novel action of DA in the initial phase of alpha-SN aggregation and demonstrate that DA induces alpha-SN to form soluble, SDS-resistant oligomers. The DA:alpha-SN oligomeric species are not amyloidogenic as they do not react with thioflavin T and lack the typical amyloid fibril structures as visualized with electron microscopy. Circular dichroism studies indicate that in the presence of lipid membranes DA interacts with alpha-SN, causing an alteration to the structure of the protein. Furthermore, DA inhibited the formation of iron-induced alpha-SN amyloidogenic aggregates, suggesting that DA acts as a dominant modulator of alpha-SN aggregation. These observations support the paradigm emerging for other neurodegenerative diseases that the toxic species is represented by a soluble oligomer and not the insoluble fibril.
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/PY16095
Abstract: End-stage renal disease (ESRD) is becoming more prevalent in Australia. As a result, strategies to improve quality of life when living with ESRD are becoming increasingly important. The Flinders Program has been developed to help support and increase the self-management capacity of people living with chronic disease. The Partners in Health (PIH) scale is a self-management capacity assessment tool, which is an integral element of the Flinders Program. The primary aim of this study was to investigate the preliminary measurement properties of the PIH scale within the ESRD population. Forty participants took part in the study, which involved survey assessments at baseline and follow up and a semi-structured interview. Results indicated that the PIH scale had good internal reliability (α=0.85), moderate test-retest reliability (r=0.33) and face validity in ESRD patients. Areas for improving the instrument or data collection process were identified through qualitative interviews, and implications are discussed specific to ESRD patients.
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1016/S0022-2836(03)00687-9
Abstract: Beta-2-microglobulin (beta(2)m) has been shown to form amyloid fibrils with distinct morphologies under acidic conditions in vitro. Short, curved fibrils (<600 nm in length), form rapidly without a lag phase, with a maximum rate at pH 3.5. By contrast, fibrils with a long (approximately 1 microm), straight morphology are produced by incubation of the protein at pH< or =3.0. Both fibril types display Congo red birefringence, bind Thioflavin-T and have X-ray fibre diffraction patterns consistent with a cross-beta structure. In order to investigate the role of different partially folded states in generating fibrils of each type, and to probe the effect of protein stability on amyloid formation, we have undertaken a detailed mutagenesis study of beta(2)m. Thirteen variants containing point mutations in different regions of the native protein were created and their structure, stability and fibril forming propensities were investigated as a function of pH. By altering the stability of the native protein in this manner, we show that whilst destabilisation of the native state is important in the generation of amyloid fibrils, population of specific denatured states is a pre-requisite for amyloid formation from this protein. Moreover, we demonstrate that the formation of fibrils with different morphologies in vitro correlates with the relative population of different precursor states.
Publisher: Informa UK Limited
Date: 02-12-2017
Publisher: Elsevier BV
Date: 07-2011
Publisher: Wiley
Date: 02-12-2019
DOI: 10.1002/JMS.4461
Abstract: Three-dimensional (3D) cell culture is a rapidly emerging field, which mimics some of the physiological conditions of human tissues. In cancer biology, it is considered a useful tool in predicting in vivo chemotherapy responses, compared with conventional two-dimensional (2D) cell culture. We have developed a novel 3D cell culture model of osteosarcoma composed of aggregated proliferative tumour spheroids, which shows regions of tumour heterogeneity formed by aggregated spheroids of polyclonal tumour cells. Aggregated spheroids show local necrotic and apoptotic regions and have sizes suitable for the study of spatial distribution of metabolites by mass spectrometry imaging (MSI). We have used this model to perform a proof-of-principle study showing a heterogeneous distribution of endogenous metabolites that colocalise with the necrotic core and apoptotic regions in this model. Cytotoxic chemotherapy (doxorubicin) responses were significantly attenuated in our 3D cell culture model compared with those of standard cell culture, as determined by resazurin assay, despite sufficient doxorubicin diffusion demonstrated by localisation throughout the 3D constructs. Finally, changes to the distribution of endogenous metabolites in response to doxorubicin were readily detected by MSI. Principal component analysis identified 50 metabolites which differed most in their abundance between treatment groups, and of these, 10 were identified by both in-software t test and mixed-effects analysis of variance (ANOVA). Subsequent independent MSIs of identified species were consistent with principle component analysis findings. This proof-of-principle study shows for the first time that chemotherapy-induced changes in metabolite abundance and distribution may be determined in 3D cell culture by MSI, highlighting this method as a potentially useful tool in the elucidation of chemotherapy responses as an alternative to in vivo testing.
Publisher: Portland Press Ltd.
Date: 15-06-2015
DOI: 10.1042/BJ20150159
Abstract: Misfolding and aggregation of α-synuclein (α-syn) into Lewy bodies is associated with a range of neurological disorders, including Parkinson's disease (PD). The cell-to-cell transmission of α-syn pathology has been linked to soluble amyloid oligomer populations that precede Lewy body formation. Oligomers produced in vitro under certain conditions have been demonstrated to induce intracellular aggregation in cell culture models. In the present study, we characterize, by ESI–ion mobility spectrometry (IMS)–MS, a specific population of α-syn oligomers. These MS-compatible oligomers were compared with oligomers with known seeding and pore-forming capabilities and were shown to have the ability to induce intracellular aggregation. Each oligomer type was shown to have distinct epitope profiles that correlated with their toxic gain-of-function. Structurally, the MS compatible oligomers populated a range of species from dimers through to hexamers. Lower-order oligomers were structurally erse and consistent with unstructured assemblies. Higher-order oligomers were shown to be compact with ring-like structures. The observation of this compact state may explain how this natively disordered protein is able to transfer pathology from cell to cell and avoid degradation by cellular proteases.
Publisher: Elsevier BV
Date: 12-2010
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.BBAMEM.2008.01.012
Abstract: There is substantial evidence which implicates alpha-synuclein and its ability to aggregate and bind vesicle membranes as critical factors in the development of Parkinson's disease. In order to investigate the interaction between alpha-synuclein wild type (Wt) and its familial mutants, A53T and A30P with lipid membranes, we developed a novel lipid binding assay using surface enhanced laser desorption/ionisation-time of flight-mass spectrometry (SELDI-TOF MS). Wt and A53T exhibited similar lipid binding profiles monomeric species and dimers bound with high relative affinity to the lipid surface, the latter of which exhibited preferential binding. Wt and A53T trimers and tetramers were also detected on the lipid surface. A30P exhibited a unique lipid binding profile monomeric A30P bound with a low relative affinity, however, the dimeric species of A30P exhibited a higher binding ability. Larger order A30P oligomers were not detected on the lipid surface. Tapping mode atomic force microscopy (AFM) imaging was conducted to further examine the alpha-synuclein-lipid interaction. AFM analysis revealed Wt and its familial mutants can penetrate lipid membranes or disrupt the lipid and bind the hydrophobic alkyl self-assembled monolayer (SAM) used to form the lipid layer. The profile of these studied proteins revealed the presence of 'small features' consistent with the presence of monomeric and dimeric forms of the protein. These data collectively indicate that the dimeric species of Wt and its mutants can bind and cause membrane perturbations.
Publisher: Public Library of Science (PLoS)
Date: 26-06-2018
Publisher: MDPI AG
Date: 25-04-2022
DOI: 10.3390/BIOM12050630
Abstract: The ision of amyloid fibril particles through fragmentation is implicated in the progression of human neurodegenerative disorders such as Parkinson’s disease. Fragmentation of amyloid fibrils plays a crucial role in the propagation of the amyloid state encoded in their three-dimensional structures and may have an important role in the spreading of potentially pathological properties and phenotypes in amyloid-associated diseases. However, despite the mechanistic importance of fibril fragmentation, the relative stabilities of different types or different polymorphs of amyloid fibrils toward fragmentation remain to be quantified. We have previously developed an approach to compare the relative stabilities of different types of amyloid fibrils toward fragmentation. In this study, we show that controlled sonication, a widely used method of mechanical perturbation for amyloid seed generation, can be used as a form of mechanical perturbation for rapid comparative assessment of the relative fragmentation stabilities of different amyloid fibril structures. This approach is applied to assess the relative fragmentation stabilities of amyloid formed in vitro from wild type (WT) α-synuclein and two familial mutant variants of α-synuclein (A30P and A53T) that generate morphologically different fibril structures. Our results demonstrate that the fibril fragmentation stabilities of these different α-synuclein fibril polymorphs are all highly length dependent but distinct, with both A30P and A53T α-synuclein fibrils displaying increased resistance towards sonication-induced fibril fragmentation compared with WT α-synuclein fibrils. These conclusions show that fragmentation stabilities of different amyloid fibril polymorph structures can be erse and suggest that the approach we report here will be useful in comparing the relative stabilities of amyloid fibril types or fibril polymorphs toward fragmentation under different biological conditions.
Publisher: Hindawi Limited
Date: 2016
DOI: 10.1155/2016/5613767
Abstract: Objective . Response time (RT) is important for health and human performance and provides insight into cognitive processes. It deteriorates with age, is associated with chronic physical activity (PA), and improves with PA interventions. We investigated associations between the amount and type of PA undertaken and the rate of change in RT for low-active adults across the age range 18–63 yr. Methods . Insufficiently active adults were assigned to either a walking ( n = 263 ) or higher-intensity ( n = 380 ) exercise program conducted over 40 days. Active controls were also recruited ( n = 135 ). Simple response time (SRT) and choice response time (CRT) were measured before and after the intervention and at 3-, 6-, and 12-month follow-up. Results . SRT and CRT slowed across the age range however, habitually active participants at baseline had significantly faster CRT ( p 0.05 ). The interventions increased weekly PA with corresponding increases in physical fitness. These changes were mirrored in faster CRT across the study for both intervention groups ( p 0.05 ). No changes were found for SRT. Conclusions . Both PA interventions resulted in improvements in CRT among adults starting from a low activity base. These improvements were relatively rapid and occurred in both interventions despite large differences in exercise volume, type, and intensity. There were no effects on SRT in either intervention.
Publisher: Wiley
Date: 21-08-2018
Abstract: Understanding how students interact and learn within the lecture theatre environment is central to successful learning outcomes. Previous studies into the use of the lecture theatre teaching space have found that students sit in specific locations due to a range of factors these include being noticed, addressing anxiety or an ability to focus. This study further explores the personal and social factors at play within students’ lecture theatre seating choice and the resulting effects on attainment. Student responses on seating preferences detailing why they chose a given location were mapped at a seat‐specific level and correlated against attainment. In parallel, staff perceptions of student attainment in relation to their seating choice were obtained. No direct correlation between student location and attainment was found, contrary to staff perceptions. Interestingly, it was found that students physically locate into friendship groups clusters and that these clusters obtained similar levels of attainment in problem‐solving tasks, with pockets of both high‐ and low‐performing students being observed. It was also noted that isolated students performed less well. These data would indicate that peer group formation exerts a strong impact on attainment and engagement. Outcomes from this study will enable academic staff to better understand the student body and inform the way in which teaching sessions are performed within a lecture theatre.
Publisher: Elsevier BV
Date: 12-2012
Publisher: SAGE Publications
Date: 10-06-2020
Abstract: To identify interventions using wearable accelerometers to measure physical activity and/or sedentary behaviour in adults during hospitalization for an acute medical/surgical condition. Four databases were searched in August 2019 (MEDLINE, CINAHL, Scopus, EMBASE). Studies were selected if they described an intervention in adults with a medical/surgical condition, and concurrently reported an accelerometer-derived measure of physical activity and/or sedentary behaviour while participants were admitted. Items were screened for eligibility in duplicate. Included studies were synthesized to describe intervention types, feasibility and potential effectiveness. Twenty-two studies were included, reporting on 3357 participants (2040 with accelerometer data). Identified types of interventions were: pre-habilitation ( n = 2) exercise ( n = 3), patient behaviour change with self-monitoring ( n = 6), models of care ( n = 5), implementing system change ( n = 2), surgical technique ( n = 2) patients wearing day clothes ( n = 1) and education about activity in hospital ( n = 1). Of 16 studies that reported intervention effects on physical activity, 11 reported a favourable impact including studies of: pre-habilitation, self-monitoring (accelerometry or an activity whiteboard), physiotherapy, an early mobility bundle, minimally invasive surgery, an education booklet and by implementing system change. Of the six studies that reported intervention effects on sedentary behaviour, there was a favourable impact with an activity whiteboard, models of care and an education booklet. Accelerometer-derived measures of physical activity and/or sedentary behaviour have been used to describe s le characteristics and intervention effects in studies of hospitalized adults. Interventions may involve a range of health professionals, but less is known about sedentary behaviour in this setting.
Publisher: Elsevier BV
Date: 2017
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for David Smith.