1,721,172 research outputs found
Optimization of nitric oxide donors for investigating biofilm dispersal response in Pseudomonas aeruginosa clinical isolates
No full textPseudomonas aeruginosa biofilms contribute heavily to chronic lung infection in cystic fibrosis patients, leading to morbidity and mortality. Nitric oxide (NO) has been shown to disperse P. aeruginosa biofilms in vitro, ex vivo and in clinical trials as a promising anti-biofilm agent. Traditional NO donors such as sodium nitroprusside (SNP) have been extensively employed in different studies. However, the dosage of SNP in different studies was not consistent, ranging from 500 nM to 500 μM. SNP is light sensitive and produces cyanide, which may lead to data misinterpretation and inaccurate predictions of dispersal responses in clinical settings. New NO donors and NO delivery methods have therefore been explored. Here we assessed 7 NO donors using P. aeruginosa PAO1 and determined that SNP and Spermine NONOate (S150) successfully reduced > 60% biomass within 24 and 2 h, respectively. While neither dosage posed toxicity towards bacterial cells, chemiluminescence assays showed that SNP only released NO upon light exposure in M9 media and S150 delivered much higher performance spontaneously. S150 was then tested on 13 different cystic fibrosis P. aeruginosa (CF-PA) isolates; most CF-PA biofilms were significantly dispersed by 250 μM S150. Our work therefore discovered a commercially available NO donor S150, which disperses CF-PA biofilms efficiently within a short period of time and without releasing cyanide, as an alternative of SNP in clinical trials in the future
Dataset supporting the University of Southampton Doctoral Thesis "Exploring the effects of redox within the bacterial biofilm lifecycle of pseudomonas aeruginosa – the importance of sensory domains"
No full textDataset supporting the University of Southampton Doctoral Thesis "Exploring the effects of redox within the bacterial biofilm lifecycle of pseudomonas aeruginosa – the importance of sensory domains".
The data is organised into projects:
Chapter3
Chapter4 - BdlA
Chapter5 - PipA
Chapter6 - RbdA
With some generalised prism files
Within each folder holds data collected for each project which led to the outputs shown in this thesis.
Please contact the author or the supervisors on the project for access to raw data which is stored at the synchrotron facilities.
Further, some data is available under PDB code 8PPS: DOI: https://doi.org/10.2210/pdb8PPS/pdb
Data available under a CC BY licence</span
Nitric Oxide-Mediated Dispersal as an Adjunctive Strategy for the Control of Biofilm-Associated Infection
No full textStructured biofilm aggregates offer an increased tolerance to antimicrobials, providing either a physical barrier to antimicrobial penetration or leading to physiological adaptations amongst biofilm bacteria that may impact on antibiotic efficacy. Consequently, biofilms are causative of a range of chronic infections where the use of antimicrobials rarely eradicates the underlying infection. One feature of the development of microbial biofilm communities is that they often undergo lifecycle changes between aggregated and planktonic modes of growth. This transition between sessile and motile growth modes is referred to as biofilm dispersal. Understanding and controlling the dispersal process is leading to novel adjunctive strategies to disrupt clinically important biofilms. Exogenous nitric oxide (NO) has been shown to regulate, in a dose-dependent manner, biofilm lifecycle dynamics and can induce the disruption of biofilm aggregates. The use of NO therefore offers a potential therapeutic approach to address the challenge of biofilm-associated antimicrobial tolerance. This chapter explores the current and prospective NO therapies and the underpinning mechanisms of NO-mediated biofilm regulation. It also reviews NO-releasing chemistries, prodrugs, and materials for clinical use
Dataset for the thesis titled 'Microbiologically influenced corrosion (MIC): Development of a model system to investigate the role of biofilm communities within MIC and their control using industrial biocides'
No full textComplete dataset for thesis:
Each separate zip folder, 28_Day_Experiment, Valhall_Langstone_Experiments, and Langstone+Glut_Experiment, contains datasets for my Thesis
28_Day_Experiment contains data for research chapter 3 (ASW+YE) and 4 (MB media) within subsequent folders for each different type of method
Valhall_Langstone_Experiments contains data for research chapter 5
Langstone+Glut_Experiment contains data for research chapter 6
Graphpad Prism and Excel software needed to view the data.
This dataset contains:
16s rRNA amplicon sequencing, ATP assay, confocal fluorescence microscopy (Live/Dead), electrochemistry (LPR, EIS, potentiodynamic polarisation), environmental data, gravimetric analysis, sulphide microsensor data, and surface profilometry data.
</span
Competitive interactions in mixed-species biofilms containing the marine bacterium pseudoalteromonas tunicata
No full textInvestigating alternative materials to EPDM for automatic taps in the context of Pseudomonas aeruginosa and biofilm control
No full textBackground
Automatic taps use solenoid valves (SVs) which incorporate a rubber (typically EPDM) diaphragm to control water flow. Contaminated SVs can be reservoirs of opportunistic pathogens such as Pseudomonas aeruginosa; an important cause of healthcare-associated infection.
Aims
To investigate the attachment and biofilm formation of P. aeruginosa on EPDM and relevant alternative rubbers to assess the impact on water hygiene in a laboratory model.
Methods
Biofilm formation on EPDM, silicone and nitrile rubber coupons was investigated using a CDC biofilm reactor. SVs incorporating EPDM or nitrile rubber diaphragms were installed on to an experimental water distribution system (EWDS) and inoculated with P. aeruginosa. P. aeruginosa water levels were monitored for 12-weeks. SVs incorporating diaphragms (EPDM, silicone or silver ion-impregnated silicone rubber), pre-colonized with P. aeruginosa, were installed and the effect of flushing as a control measure was investigated. The concentration of P. aeruginosa in the water was assessed by culture and biofilm assessed by culture and microscopy.
Findings
Bacterial attachment was significantly higher on nitrile (6.2 × 105 cfu/coupon) and silicone (5.4 × 105 cfu/coupon) rubber than on EPDM (2.9 ×105 cfu/coupon) (P<0.05, N = 17). Results obtained in vitro did not translate to the EWDS where, after 12-weeks in situ, there was no significant difference in P. aeruginosa water levels or biofilm levels. Flushing caused a superficial reduction in bacterial counts after <5 min of stagnation.
Conclusion
This study did not provide evidence to support replacement of EPDM with (currently available) alternative rubbers and indicated the first sample of water dispensed from a tap should be avoided for use in healthcare settings
Systems Aikido: a novel approach to managing natural systems
No full textThe potential of new technologies which emulate or exploit the unique properties of living systems is widely lauded. Such technologies however, create new engineering challenges which must be addressed before they can become broadly utilised (see for example, Braha et al. (2006); Bedau et al. (2010); Penn (2008)). Additionally, many pressing challenges for society today are inherently concerned with gaining a better ability to understand and manage interacting living or life-like systems upon which we rely. Well-documented examples include climate change, agricultural sustainability, city dynamics, demographic change and chronic infections. Problems in all these areas demand a better ability to manage complex biological systems than is currently available.Conventional approaches to working with biological systems are, for the most part, brute force, attempting to effect control in an input and effort intensive manner and are often insufficient when dealing with the inherent non-linearity and complexity of living systems. Biological systems, by their very nature, are dynamic, adaptive and resilient and require management tools that interact with dynamic processes rather than inert artifacts. Our novel engineering approach which aims to exploit rather than fight those properties, presents a more efficient and robust alternative. Its essence is what I will call systems aikido, the basic principle of aikido being to interact with the momentum of an attacker and redirect it with minimal energy expenditure, using the opponents energy rather than ones own. In more conventional terms, this translates to a philosophy of equilibrium engineering, manipulating systems own self-organisation and evolution so thatthe evolutionarily or dynamically stable state corresponds to a function which we require.I will discuss how we might move from this philosophy to a practical methodology for management of living systems and technologies, covering a variety of approaches: Designing-in of tools for adaptive management given unexpected indirect effects and continuous adaptation of living components; identification of appropriate points of intervention in particular systems; and methods for steering adaptive systems by altering either the fitness landscape which they experience or the attractor structure of their dynamics. Filling fitness valleys to escape local optima; expansion of basins of attraction of difficult to access, but favourable attractors and manipulating the effective level of selection within the system.Detailed illustration is provided by a practical application: Manipulating the level of selection within bacterial biofilms, such that stable community species and genetic composition corresponds to a community function which we require (Penn et al. (2008b,a)). Different levels of selection produce particular types of community composition. Higher-level selection promotes co-operation and synergy useful for efficient bioremediation and bioproduction, whereas encouraging lowerlevel selection might allow us to engineer a tragedy of the commons in problematic bacterial communities. I will present methodology and results from ongoing experimental work with Psuedomonas aeruginosa biofilms in which direct or indirect manipulation of parameters affecting group structure and dispersal mechanisms modify the effective level of and hence response to selection. And will describe approaches to increase the robustness of the engineered communityFinally I will contrast this methodology with a spectrum of more or less brute-force interventions, from traditional biofilm engineering approaches to imposition of higher-level selection( Swenson et al. (2000b,a); Penn (2006))
Application of denaturing gradient gel electrophoresis (DGGE) in microbial ecology
No full textBecause of the difficulty associated with isolating and culturing bacteria from environmental samples, alternative methods based on molecular techniques have been developed to describe and identmicrobial communities. Recent years have witnessed a rapid development of DNA-based methods for community analysis such as PCR amplification, clone libraries, fluorescent in-situ hybridisation,restriction fragment length polymorphism，denaturing and temperature gradient gel electrophoresis. DGGE has been widely used in analyzing the biodiversity of bacterial, cyanobacterial, archaeal,picoeukaryotic, eukaryotic and viral communities in natural habitats. This technique can provide information on the predominant species in a community and analyze multiple samples simultaneously. The reproducibility and ease-of use of this technique perm it investigation of the spatial and temporal variability of the population and identification of community m em hers by sequencing of excised bands or by hybridization analysis with specific probes
- …
