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Davey, Hazel M.

doi:10.1023/a:1024106317540

Cited by 44 publications

(7 citation statements)

References 36 publications

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“…Total cell counts could be used as an early indication of total viable counts and provide a more accurate enumeration of bacilli in the BCG vaccine as it counts bacilli that are present in the culture but cannot be cultured on agar. Flow cytometry has been used previously to enumerate bacteria, with an accurate reflection of viable bacterial load [30][31][32]. This is the first time that flow cytometry has been used for population-wide analyses of the metabolic status of fermented M. bovis BCG.…”

Section: Discussionmentioning

confidence: 99%

Optimisation of Mycobacterium bovis BCG Fermentation and Storage Survival

et al. 2020

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Mycobacterium bovis Bacillus Calmette–Guérin (M. bovis BCG) was generated over a century ago for protection against Mycobacterium tuberculosis (Mtb) and is one the oldest vaccines still in use. The BCG vaccine is currently produced using a pellicle growth method, which is a complex and lengthy process that has been challenging to standardise. Fermentation for BCG vaccine production would reduce the complexity associated with pellicle growth and increase batch to batch reproducibility. This more standardised growth lends itself to quantification of the total number of bacilli in the BCG vaccine by alternative approaches, such as flow cytometry, which can also provide information about the metabolic status of the bacterial population. The aim of the work reported here was to determine which batch fermentation conditions and storage conditions give the most favourable outcomes in terms of the yield and stability of live M. bovis BCG Danish bacilli. We compared different media and assessed growth over time in culture, using total viable counts, total bacterial counts, and turbidity throughout culture. We applied fluorescent viability dyes and flow cytometry to measure real-time within-culture viability. Culture samples were stored in different cryoprotectants at different temperatures to assess the effect of these combined conditions on bacterial titres. Roisin’s minimal medium and Middlebrook 7H9 medium gave comparable, high titres in fermenters. Flow cytometry proved to be a useful tool for enumeration of total bacterial counts and in the assessment of within-culture cell viability and cell death. Of the cryoprotectants evaluated, 5% (v/v) DMSO showed the most significant positive effect on survival and reduced the negative effects of low temperature storage on M. bovis BCG Danish viability. In conclusion, we have shown a reproducible, more standardised approach for the production, evaluation, and storage of high titre, viable, BCG vaccine.

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Section: Discussionmentioning

confidence: 99%

Optimisation of Mycobacterium bovis BCG Fermentation and Storage Survival

et al. 2020

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“…Typically, immunologists use high-throughput methods of analysis and integrate the experimental data with clinical and epidemiological evidence. 29 − 31 The current progress of the omics platforms enables a deeper level of knowledge resulting in a huge amount of data, for which the management and fruitful integration with past findings requires a steadily growing computational effort. 28 , 32 In light of this, immunoinformatics has emerged as a new discipline placed in between the traditional wet-lab based investigations and the computational analysis of the biological data.…”

Section: Computational Immune Proteomicsmentioning

confidence: 99%

Computational Immune Proteomics Approach to Target COVID-19

et al. 2020

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Progress of the omics platforms widens their application to diverse fields, including immunology. This enables a deeper level of knowledge and the provision of a huge amount of data for which management and fruitful integration with the past evidence requires a steadily growing computational effort. In light of this, immunoinformatics emerges as a new discipline placed in between the traditional lab-based investigations and the computational analysis of the biological data. Immunoinformatics make use of tailored bioinformatics tools and data repositories to facilitate the analysis of data from a plurality of disciplines and help drive novel research hypotheses and in silico screening investigations in a fast, reliable, and cost-effective manner. Such computational immunoproteomics studies may as well prepare and guide lab-based investigations, representing valuable technology for the investigation of novel pathogens, to tentatively evaluate specificity of diagnostic products, to forecast on potential adverse effects of vaccines and to reduce the use of animal models. The present manuscript provides an overview of the COVID-19 pandemic and reviews the state of the art of the omics technologies employed in fighting SARS-CoV-2 infections. A comprehensive description of the immunoinformatics approaches and its potential role in contrasting COVID-19 pandemics is provided.

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“…Plate counting has the advantage of allowing the measurement of viable cell numbers. FCM is a fast and precise method to count cells [29]. Furthermore, this method is able to directly count hundreds of thousands of cells in a single sample, thereby facilitating the generation of statistically meaningful results.…”

Section: Introductionmentioning

confidence: 99%

Effect of spaceflight on Pseudomonas aeruginosa final cell density is modulated by nutrient and oxygen availability

et al. 2013

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BackgroundAbundant populations of bacteria have been observed on Mir and the International Space Station. While some experiments have shown that bacteria cultured during spaceflight exhibit a range of potentially troublesome characteristics, including increases in growth, antibiotic resistance and virulence, other studies have shown minimal differences when cells were cultured during spaceflight or on Earth. Although the final cell density of bacteria grown during spaceflight has been reported for several species, we are not yet able to predict how different microorganisms will respond to the microgravity environment. In order to build our understanding of how spaceflight affects bacterial final cell densities, additional studies are needed to determine whether the observed differences are due to varied methods, experimental conditions, or organism specific responses.ResultsHere, we have explored how phosphate concentration, carbon source, oxygen availability, and motility affect the growth of Pseudomonas aeruginosa in modified artificial urine media during spaceflight. We observed that P. aeruginosa grown during spaceflight exhibited increased final cell density relative to normal gravity controls when low concentrations of phosphate in the media were combined with decreased oxygen availability. In contrast, when the availability of either phosphate or oxygen was increased, no difference in final cell density was observed between spaceflight and normal gravity. Because motility has been suggested to affect how microbes respond to microgravity, we compared the growth of wild-type P. aeruginosa to a ΔmotABCD mutant deficient in swimming motility. However, the final cell densities observed with the motility mutant were consistent with those observed with wild type for all conditions tested.ConclusionsThese results indicate that differences in bacterial final cell densities observed between spaceflight and normal gravity are due to an interplay between microgravity conditions and the availability of substrates essential for growth. Further, our results suggest that microbes grown under nutrient-limiting conditions are likely to reach higher cell densities under microgravity conditions than they would on Earth. Considering that the majority of bacteria inhabiting spacecrafts and space stations are likely to live under nutrient limitations, our findings highlight the need to explore the impact microgravity and other aspects of the spaceflight environment have on microbial growth and physiology.

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Untitled

Cited by 44 publications

References 36 publications

Optimisation of Mycobacterium bovis BCG Fermentation and Storage Survival

Optimisation of Mycobacterium bovis BCG Fermentation and Storage Survival

Computational Immune Proteomics Approach to Target COVID-19

Effect of spaceflight on Pseudomonas aeruginosa final cell density is modulated by nutrient and oxygen availability

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