1,720,987 research outputs found
Development of a sensitive cell culture system to assess prion infectivity and the efficacy of prion decontamination technologies
No full textCreutzfeldt-Jakob disease (CJD) can be iatrogenically transmitted during transplants, grafts and transfusions from CJD infected donors and also contaminated surgical instruments. A variety of methods to amplify and detect the presence of infectious prions as disease markers are available. However, these techniques do not measure the infectivity potentially associated with these markers. Currently, animal-bioassays are used to detect infectivity; however, they have limitations in detectable prion strains, cost, ethical considerations and assay length. Novel cell-based infectivity assays offer the potential to overcome these limitations, lower the requirements for animal use and the application of different cell lines could detect a wider range of prion strains. This project utilised murine neuroblastoma, N2a #58 cells infected with 22L-murine scrapie to develop a highly sensitive assay for the in situ detection of amyloid-rich prion (PrPSc) accumulation as an indication of prion infectivity. The autofluorescence quenching properties of Sudan black (SB) were incorporated into a novel Thioflavin T (ThT) based protocol for amyloid staining with improved specificity and sensitivity. Cell passages were incorporated into the assay to increase incubation time, improve cell viability and subsequently improve assay sensitivity; thus, demonstrating the detection of infectivity from a final 10-10 dilution of 22L-infected brain homogenate. Introduction of 22L-inoculated, surgical grade stainless steel wires to the N2a #58 cells demonstrated the SB/ThT detection of prion infectivity pre and post decontamination, which was comparable to animal bioassay data. Furthermore, preliminary work on the incorporation of the SB/ThT detection of prion infectivity within neural stem cells (NSC’s), for prion propagation within a cell line that did not require genetic manipulation for increased prion susceptibility, highlighted problems with unspecific fluorescence of dead cells during NSC differentiation. Improvements in culture conditions of the NSC’s regarding atmospheric conditions and trophic support were addressed in preparation for their use in future prion infectivity assays
A rapid dual staining procedure for the quantitative discrimination of prion amyloid from tissues reveals how interactions between amyloid and lipids in tissue homogenates may hinder the detection of prions
No full textTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases with no cure to this day, and are often associated with the accumulation of amyloid plaques in the brain and other tissues in affected individuals. The emergence of new variant Creutzfeldt-Jakob disease, an acquired TSE with a relatively long asymptomatic incubation period and unknown prevalence or incidence, which could potentially be iatrogenically transmitted, has prompted the need for sensitive and rapid methods of detection of the pathology indicator, the protease-resistant prion protein (PrP(Sc)), in tissues and on surgical instruments. To discriminate between common tissue proteins and amyloid-rich aggregates such as those formed by abnormal prion, we developed a quantitative thioflavin T/SYPRO Ruby dual staining procedure, used in combination with episcopic differential interference contrast/epifluorescence (EDIC/EF) microscopy for rapid scanning of samples. The detection limit of this direct observation technique applied to brain homogenates was greatly enhanced by the addition of Tween 20, as demonstrated in double-blind studies using various proportions of ME7-infected brain mixed with normal brain homogenate. The characteristic thioflavin T signal correlated with the relative amount of prion amyloid and proved at least 2-log more sensitive than the classic Western blot using the same prepared samples. This new sensitive microscopy procedure, which can be easily applied in instrument decontamination surveys, is likely to be more sensitive that Western blot in practice since it does not rely on the elution of resilient PrP(Sc) bound to the instrument surfaces. Our study also demonstrates how interactions between prion and lipid-rich tissue homogenates may reduce the sensitivity of such detection assays
The possibilities of using Ultrasonically Activated Streams to reduce the risk of foodborne infection from salad
No full textIn this study, we investigated the effects of an ultrasonically activated stream (UAS) on the removal of microbial contaminants from spinach leaves. The microbial loads on samples cleaned with and without UAS were enumerated using the cell culture method and compared against unwashed samples on day 0 and day 6 after cleaning. The effects of UAS cleaning on leaf quality were also examined through both macroscopic and microscopic inspection, as well as measurement of the electrolyte leakage rate. Results showed that the microbial load on samples cleaned with UAS for 2 min was significantly lower on day 6 after cleaning than on those treated without ultrasound. Comparison between the cleaning effects of UAS for 40 s versus 2 min indicated that a cleaning duration of 2 min allowed sufficient time for UAS to disaggregate and detach the microbial contamination more effectively. In this case, the induction of bacteria into a viable but non-culturable state does not affect the shelf-life test results as much as it does with a 40 s clean. UAS cleaning for 2 min did not produce significant surface damage, which can affect overall leaf quality. These findings highlight the potential of UAS systems in the salad industry to improve the microbiological quality and shelf life of salads.</p
Dataset supporting University of Southampton Doctoral thesis: Investigating ways to improve food safety: ultrasonic salad cleaning
No full textDataset supporting a PhD thesis "Investigating ways to improve food safety: ultrasonic salad cleaning".</span
Dataset for Bubbles vs biofilms: a novel method for the removal of marine biofilms attached on antifouling coatings using an ultrasonically activated water stream
No full textDataset to support:
Salta, M. et al (2016) Bubbles vs biofilms: a novel method for the removal of marine biofilms attached on antifouling coatings using an ultrasonically activated water stream. Surface Topography: Metrology and Properties.</span
Improving livestock feed safety and infection prevention: Removal of bacterial contaminants from hay using cold water, bubbles and ultrasound
No full textThe ingestion of contaminated hay is detrimental to livestock wellbeing. In this study, the feasibility of using an ultrasonically activated stream (UAS) to clean bacterial contamination from hay was investigated. Hay samples were stained with SYTO-9 nucleic acid stain for the in-situ visualization of microbes on the surface using an episcopic differential interference contrast microscope coupled with epi-fluorescence. The total microbial load per sample was calculated by measuring the mean percentage area of SYTO-9 positive staining. The cleaning efficacy was evaluated by comparing the total microbial coverage before and after cleaning. The cleaning performance between an UAS and a non UAS were compared and results have shown that an exposure of 60 s to an UAS demonstrated an 87.94 ± 2.22% removal of the bacterial contaminants, exceeding that of non UAS (21.85 ± 13.63% removal). UAS is capable of removing bacterial contaminants without the use of antimicrobial agents, therefore its cleaning mechanism can potentially prevent infection and reduce antimicrobial resistance. The cleaning mechanism of UAS can be adapted for the development of a new hay cleaning strategy for effective removal of bacterial contaminant to improve feed safety.</p
Dataset for: "A proof‐of‐concept study of the removal of early and late phase biofilm from skin wound models using a liquid acoustic stream"
No full textThis dataset contains: The raw data of the image analysis of the percentage coverage measurements in figures 3 and 4, and the measurements of re-epithelialisation in figures 6 and 7</span
Dataset for: The possibilities of using Ultrasonically Activated Streams to reduce the risk of foodborne infection from salad
No full textDataset supports: Chong, W.Y., Secker, T., Dolder, C., Keevil, C., & Leighton, T. (2021). The possibilities of using Ultrasonically Activated Streams to reduce the risk of foodborne infection from salad. Ultrasound in Medicine & Biology (in press)</span
Dataset for: Improving livestock feed safety and infection prevention: Removal of bacterial contaminants from hay using cold water, bubbles and ultrasound  
No full textDataset supports: Chong, W. Y., Cox, C., Secker, T., Keevil, C., & Leighton, T. (2021). Improving livestock feed safety and infection prevention: Removal of bacterial contaminants from hay using cold water, bubbles and ultrasound  . Ultrasonics Sonochemistry, 71, [105372]. </span
- …
