Periodic Reporting for period 1 - a-Sign (Cyclic nucleotide signalling in the human pathogen Listeria monocytogenes)
Reporting period: 2016-05-01 to 2018-04-30
The bacterium used in this study was Listeria monocytogenes, one of the most virulent foodborne pathogens, causing febrile gastroenteritis and listeriosis, and affecting pregnant women, newborns, immunocompromised individuals, and the elderly.
To understand how L. monocytogenes survives to the environment is important because the population of the Western countries is ageing and the elderly are a risk group. Since 2012, the number of listeriosis cases has been in constant increase.
In this project, the cyclic nucleotides (cAMP, cGMP, c-di-AMP and c-di-GMP) and their regulatory function (including virulence and antimicrobial resistance), were investigated.
It was observed that L. monocytogenes extracts have cAMP levels similar to those in Escherichia coli extracts. The cAMP molecule was detected in bacteria grown aerobically in rich or chemically defined medium, and levels were higher in exponential phase than in stationary phase. The cGMP molecule was detected but levels were considered residual.
In the screen, four deletion mutants were found to have an altered cyclic nucleotide profile. One of them displayed low levels of c-di-GMP and was associated with a higher tolerance to ethanol, higher sensitivity to ampicillin and hypervirulent phenotype.
The results of this project were presented at a Gordon Conference in the USA (as oral and poster presentations), the i3S post-doc seminar, and the i3S annual meting. My topic of research was also presented in 3 schools, to a total of 150 pupils aged 13-17. A manuscript for publication in a peer-reviewed international journal is in preparation.
By bringing expertise acquired at other institutions/countries to i3S and designing my own project, I introduced a new line of research in the group of Dr Didier Cabanes and I set up a new technique in the lab. Peers in the lab and from a neighbouring group were able to take advantage of this technique and, reciprocally, I was able to gain new expertise from them.
I supervised three BSc students who developed their final year reports based on work from this project, and therefore concluded their first higher education degree. I continued managing and promoting school visits implemented by Native Scientist and I attended two international conferences.
Finally, during the time of this project I was elected Post-doc representative of the host institution, which meant that I have actively engaged with my peers, participated in executive meetings, organised three events on career development and designed a strategy to raise funds for science in society.