Identification and characterisation of anti - Pseudomonas aeruginosa proteins in mucus of the brown garden snail, Cornu aspersum

ABSTRACT

Background: Novel antimicrobial treatments are urgently needed. Previous work has shown that the mucus of the brown garden snail (Cornu aspersum) has antimicrobial properties, in particular against type culture collection strains of Pseudomonas aeruginosa. We hypothesised that it would also be effective against clinical isolates of the bacterium and that investigation of fractions of the mucus would identify one or more proteins with anti-pseudomonal properties, which could be further characterised.

Materials and methods: Mucus was extracted from snails collected from the wild. Antimicrobial activity against laboratory and clinical isolates of Ps. aeruginosa was determined in disc diffusion assays. Mucus was purified using size exclusion chromatography and fractions containing anti-pseudomonal activity identified. Mass spectroscopy and high performance liquid chromatography analysis of these fractions yielded partial peptide sequences. These were used to interrogate an RNA transcriptome generated from whole snails.

Results: Mucus from C. aspersum inhibited growth of type collection strains and clinical isolates of Ps. aeruginosa. Four novel C. aspersum proteins were identified; at least three are likely to have antimicrobial properties. The most interesting is a 37.4 kDa protein whilst smaller proteins, one 17.5 kDa and one 18.6 kDa also appear to have activity against Ps. aeruginosa.

Conclusions: The study has identified novel proteins with antimicrobial properties which could be used to develop treatments for use in human medicine.

KEYWORDS:

• Antimicrobial
• transcriptome
• lectin
• mucus
• Cornu aspersum
• Pseudomonas aeruginosa
• transcriptome

Acknowledgements

We would like to thank Mrs C Dedi and Ms R Berterelli and Mrs H Catty at Brighton University for technical assistance. We would also like to thank Prof Eshwar Mahenthiralingam of Cardiff University and Dr Brian Jones at Brighton University for supplying the clinical isolates of Pseudomonas aeruginosa and Dr Steve Lynham and Dr Malcolm Ward of King’s College London, Dr Chris Taron of New England Biolabs and Dr Luca Lenzi of Liverpool University for providing scientific and technical expertise. We are grateful to Prof D Timson and Dr L Bowler at Brighton University and Dr G Weedall at Liverpool John Moores University for discussions of the results.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

JAH was supported by a Research Development Grant from the Society for Applied Microbiology; SJP received support from a University of Brighton Rising Stars Award and an Output Enhancement Fund. AG received funding from the SCSTD voucher scheme at Liverpool John Moores University.