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McCarte B, Yeung OT, Speakman AJ, Elfick A, Dunn KE. Using ultraviolet absorption spectroscopy to study nanoswitches based on non-canonical DNA structures. Biochem Biophys Rep 2022; 31:101293. [PMID: 35677630 PMCID: PMC9167695 DOI: 10.1016/j.bbrep.2022.101293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 02/21/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022] Open
Abstract
Non-canonical forms of DNA are attracting increasing interest for applications in nanotechnology. It is frequently convenient to characterize DNA molecules using a label-free approach such as ultraviolet absorption spectroscopy. In this paper we present the results of our investigation into the use of this technique to probe the folding of quadruplex and triplex nanoswitches. We confirmed that four G-quartets were necessary for folding at sub-mM concentrations of potassium and found that the wrong choice of sequence for the linker between G-tracts could dramatically disrupt folding, presumably due to the presence of kinetic traps in the folding landscape. In the case of the triplex nanoswitch we examined, we found that the UV spectrum showed a small change in absorbance when a triplex was formed. We anticipate that our results will be of interest to researchers seeking to design DNA nanoswitches based on quadruplexes and triplexes. Ultraviolet absorption spectroscopy can probe non-canonical DNA structures. Absorbance at 295 nm tends to increase as G-quadruplexes form. Four G-quartets are needed to form a quadruplex with less than 1 mM potassium. Formation of DNA triplexes can also yield a small change in UV spectra. UV absorption is a cheap label-free method for studying DNA nanoswitches.
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Vallatos A, Maguire JM, Pilavakis N, Cerniauskas G, Sturtivant A, Speakman AJ, Gourlay S, Inglis S, McCall G, Davie A, Boyd M, Tavares AAS, Doherty C, Roberts S, Aitken P, Mason M, Cummings S, Mullen A, Paterson G, Proudfoot M, Brady S, Kesterton S, Queen F, Fletcher S, Sherlock A, Dunn KE. Adaptive Manufacturing for Healthcare During the COVID-19 Emergency and Beyond. Front Med Technol 2021; 3:702526. [PMID: 35047941 PMCID: PMC8757720 DOI: 10.3389/fmedt.2021.702526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/06/2021] [Indexed: 01/25/2023] Open
Abstract
During the COVID-19 pandemic, global health services have faced unprecedented demands. Many key workers in health and social care have experienced crippling shortages of personal protective equipment, and clinical engineers in hospitals have been severely stretched due to insufficient supplies of medical devices and equipment. Many engineers who normally work in other sectors have been redeployed to address the crisis, and they have rapidly improvised solutions to some of the challenges that emerged, using a combination of low-tech and cutting-edge methods. Much publicity has been given to efforts to design new ventilator systems and the production of 3D-printed face shields, but many other devices and systems have been developed or explored. This paper presents a description of efforts to reverse engineer or redesign critical parts, specifically a manifold for an anaesthesia station, a leak port, plasticware for COVID-19 testing, and a syringe pump lock box. The insights obtained from these projects were used to develop a product lifecycle management system based on Aras Innovator, which could with further work be deployed to facilitate future rapid response manufacturing of bespoke hardware for healthcare. The lessons learned could inform plans to exploit distributed manufacturing to secure back-up supply chains for future emergency situations. If applied generally, the concept of distributed manufacturing could give rise to "21st century cottage industries" or "nanofactories," where high-tech goods are produced locally in small batches.
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Affiliation(s)
- Antoine Vallatos
- Centre for Clinical Brain Sciences, Chancellor's Building, University of Edinburgh, Edinburgh, United Kingdom
| | - James M. Maguire
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Nikolas Pilavakis
- School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | | | - Steve Gourlay
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Scott Inglis
- Department of Medical Physics, NHS Lothian, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Graham McCall
- AESSiS - Advanced Engineering Solutions, London, United Kingdom
| | - Andrew Davie
- Department of Medical Physics, NHS Lothian, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Mike Boyd
- uCreate Studio, Main Library, University of Edinburgh, George Square, Edinburgh, United Kingdom
| | - Adriana A. S. Tavares
- British Heart Foundation/University of Edinburgh Centre for Cardiovascular Science and Edinburgh Imaging, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Connor Doherty
- Department of Medical Physics, NHS Lothian, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Sharen Roberts
- Department of Medical Physics, NHS Lothian, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Paul Aitken
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Mark Mason
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Scott Cummings
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew Mullen
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Gordon Paterson
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew Proudfoot
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Sean Brady
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
| | - Steven Kesterton
- Department of Medical Physics, NHS Lothian, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Fraser Queen
- Lomond Process Engineering, Glasgow, United Kingdom
| | | | - Andrew Sherlock
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
- Shapespace, Edinburgh, United Kingdom
| | - Katherine E. Dunn
- School of Engineering, University of Edinburgh, Edinburgh, United Kingdom
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Binns SH, Dawson S, Speakman AJ, Cuevas LE, Hart CA, Gaskell CJ, Morgan KL, Gaskell RM. A study of feline upper respiratory tract disease with reference to prevalence and risk factors for infection with feline calicivirus and feline herpesvirus. J Feline Med Surg 2000; 2:123-33. [PMID: 11716607 DOI: 10.1053/jfms.2000.0084] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A cross-sectional survey of a convenience sample of cats was carried out to determine the prevalence of and risk factors for respiratory tract disease, feline calicivirus (FCV) infection and feline herpesvirus (FHV) infection. Seven hundred and forty cats were studied; samples for isolation of FCV and FHV were obtained from 622 (84%). Data on individual cat and household variables were obtained by questionnaire for each cat and analysed using univariable and logistic regression analysis. Thirty-eight percent (282/740) of cats surveyed had respiratory tract disease. Eighteen of 24 predictor variables were found to be significantly (P<0.05) associated with the presence of respiratory tract disease in a cat on univariable analysis. Following logistic regression, several factors retained significance including isolation of FCV and FHV, younger cats (4-11 months of age) and multiple cat households. A negative association was found with breeding catteries and other types of household in comparison with rescue catteries. Overall, feline calicivirus was isolated from 162/622 (26%) of cats sampled; 33% of the cats with respiratory tract disease were FCV positive compared to 21% of healthy cats. Variables significantly associated with FCV isolation on logistic regression were the presence of respiratory tract disease and contact with dogs with and without respiratory tract disease. Feline herpesvirus was isolated from 30/622 (5%) of all cats sampled; 11% of cats with respiratory tract disease were FHV positive compared to 1% of healthy cats. Variables significantly associated with FHV isolation on univariable analysis included age, gender, and the presence of respiratory tract disease. Vaccination showed a negative association. Logistic regression analysis of the data for FHV was limited by the sample size and the low prevalence of FHV.
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Affiliation(s)
- S H Binns
- Department of Clinical Veterinary Science, University of Bristol, Langford, UK
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Abstract
The antimicrobial sensitivities of 78 recent (1995-1998) canine isolates of Bordetella bronchiseptica from 13 separate sources were determined. Minimum inhibitory concentrations were assessed using the E-test method or by agar dilution. All 78 isolates were sensitive to tetracycline, doxycycline, enrofloxacin, and amoxycillin/clavulanic acid; the majority were sensitive to ampicillin (63/78; 81%), trimethoprim (57/78; 73%), and sulphadiazine (63/78; 81%). Plasmids were detected in 14 out of the 24 isolates tested. There was no correlation between the presence of plasmids and antibiotic resistance, but there was some correlation between the presence of plasmids and the origin of the isolates. Three sizes of plasmid were found: 20, 14, and 5.5 kb. Eight of the isolates contained all three plasmids, the remainder one or two, Thirteen isolates demonstrated beta-haemolysis, of which six produced a soluble haemolysin. Except for one isolate, haemolysin production correlated with plasmid carriage. Pulsed-field gel electrophoresis showed that all except one isolate could be grouped in the same genotype. Within this genotype isolates could be divided into three subtypes, generally corresponding to their place of origin.
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Affiliation(s)
- A J Speakman
- Department of Veterinary Pathology, University of Liverpool, UK
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Binns SH, Dawson S, Speakman AJ, Cuevas LE, Gaskell CJ, Hart CA, Morgan KL, Gaskell RM. Prevalence and risk factors for feline Bordetella bronchiseptica infection. Vet Rec 1999; 144:575-80. [PMID: 10378288 DOI: 10.1136/vr.144.21.575] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A cross-sectional survey of a convenience-sample of 740 cats was undertaken to obtain an estimate of the prevalence of Bordetella bronchiseptica infection, and to identify risk factors that might predispose them to the infection. Data on individual cats and household variables, including disease status and animal contacts were obtained by questionnaire. B bronchiseptica was isolated from 82 (11 per cent) of the cats sampled. The prevalence of B bronchiseptica varied with the type of household sampled, being 19.5 per cent in rescue catteries, 9 per cent in breeding catteries, 13.5 per cent in research colonies, and 0 per cent in household pets. On the basis of a univariable analysis, 19 of 29 predictor variables were found to be significantly associated with the isolation of B bronchiseptica, including an association with cats in rescue catteries, and with cats from premises with larger numbers of animals. Separate analysis of the rescue cattery subpopulation showed a highly significant association on multivariable analysis with current respiratory disease, suggesting that different risk factors may operate in this type of environment. In the whole sample there was also strong association with cats from households containing a dog with recent respiratory tract disease. The clinical signs observed in the B bronchiseptica-positive cats included sneezing, ocular and nasal discharges and coughing, although only the association with sneezing was statistically significant. There was no significant association between the isolation of B bronchiseptica and the isolation of respiratory viruses, suggesting that in some circumstances B bronchiseptica may be able to cause disease independently.
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Affiliation(s)
- S H Binns
- Department of Veterinary Pathology, University of Liverpool
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Binns SH, Speakman AJ, Dawson S, Bennett M, Gaskell RM, Hart CA. The use of pulsed-field gel electrophoresis to examine the epidemiology of Bordetella bronchiseptica isolated from cats and other species. Epidemiol Infect 1998; 120:201-8. [PMID: 9593491 PMCID: PMC2809391 DOI: 10.1017/s0950268897008613] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A collection (164) of isolates of Bordetella bronchiseptica made predominantly from cats (132) but also from dogs (15), pigs (12) and other species was examined by pulsed field gel electrophoresis following macrorestriction digestion with XbaI. Each isolate was analysed twice and the patterns were entirely reproducible. The isolates fell into 17 different strains (> 3 bands different) and within strains there were numerous subtypes. Feline isolates fell into 12 of the 17 strains. In general, cats housed together had similar or identical strains and subtypes of B. bronchiseptica. There was no difference in the PFGE patterns of isolates made from carrier cats and those from cats with respiratory disease. Isolates from pigs and dogs were in general similar to the feline isolates and there was no great evidence for species specificity. The PFGE pattern of feline and canine isolates were more related to whether the animals were housed together rather than whether they came from dogs or cats.
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Affiliation(s)
- S H Binns
- Department of Veterinary Pathology, Centre for Comparative Infectious Diseases, University of Liverpool, UK
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Speakman AJ, Binns SH, Osborn AM, Corkill JE, Kariuki S, Saunders JR, Dawson S, Gaskell RM, Hart CA. Characterization of antibiotic resistance plasmids from Bordetella bronchiseptica. J Antimicrob Chemother 1997; 40:811-6. [PMID: 9462432 DOI: 10.1093/jac/40.6.811] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Of 52 antibiotic-resistant Bordetella bronchiseptica isolates from cats, ten carried plasmids. Only two of these plasmids, pLV1400 and pLV1401, were self-transmissible to Escherichia coli K12; both plasmids encoded resistance to ampicillin, tetracycline, sulphonamides, streptomycin and mercuric chloride, and were of incompatibility group P (IncP). Transferable tetracycline resistance has not been reported in B. bronchiseptica previously. The plasmids were identical in size (c.51 kb), restriction endonuclease digestion pattern and gene sequences (trfA and korA) within the IncP replicon. The trfA and korA sequences differed from those of the archetypal IncP plasmids RP4 and R751. Although the two B. bronchiseptica isolates were from epidemiologically and geographically separated cats, pulsed-field gel electrophoresis of their XbaI- or DraI-digested chromosomal DNA indicated that they were genotypically identical. The plasmid-encoded ampicillin resistance was mediated by a penicillinase of molecular weight 49,000, and pI 8.45 which was inhibited by clavulanate (IC50 = 0.1 mg/L) and tazobactam (IC50 = 0.42 mg/L) but not by parachloromercuribenzoate or EDTA. The high-level tetracycline resistance was mediated by a class C efflux mechanism that has not been described previously in this genus. The presence of transferable multi-drug resistance on a promiscuous plasmid may limit options for therapy of respiratory tract infection in companion and farm animals.
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Affiliation(s)
- A J Speakman
- Department of Veterinary Pathology, University of Liverpool, UK
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Speakman AJ, Binns SH, Dawson S, Hart CA, Gaskell RM. Antimicrobial susceptibility of Bordetella bronchiseptica isolates from cats and a comparison of the agar dilution and E-test methods. Vet Microbiol 1997; 54:63-72. [PMID: 9050171 DOI: 10.1016/s0378-1135(96)01256-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
One hundred and fifty-two predominantly feline isolates of Bordetella bronchiseptica were tested for their susceptibility to seven antimicrobial agents using an agar dilution method. The majority of isolates tested by the agar dilution method were resistant to trimethoprim (MIC90 500 micrograms/ml) and ampicillin (MIC90 > 32 micrograms/ml) but sensitive to tetracycline, doxycycline and enrofloxacin (MIC90 2 micrograms/ml for all three agents). The isolates showed a spectrum of susceptibility to sulphadiazine and clavulanate potentiated amoxycillin. The MIC's of twenty-nine of the 152 isolates were then compared for five of the antimicrobial agents using the E-test (AB Biodisk, Sweden), a recently introduced method for measuring the MIC's of antimicrobial agents based on the diffusion of a pre-defined antibiotic gradient from a plastic strip. Comparisons with the E-test demonstrated an overall agreement (+/- 1 log2 dilution) with the agar dilution method of 79.4% and an agreement within +/- 2 log2 dilutions of 96.2%.
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Affiliation(s)
- A J Speakman
- Department of Veterinary Pathology, University of Liverpool, UK.
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