Doctoral Dissertation: MSc Sami Pietilä

    MSc Sami Pietilä presents his thesis “Data-independent acquisition mass spectrometry is a feasible method for the human gut microbiota analysis” for public examination in the University of Turku on Thursday January 13th, 2022 at 12.00. Audience can follow the defence remotely:

    Professor Lennart Martens (Ghent University, Belgium) has been nominated as the opponent, and Professor Laura Elo (University of Turku) as the custos. The language of the dissertation will be English. The field of study is medical microbiology and immunology.

    The functions carried out by human gut microbiota can be studied by identifying microbiota originated proteins. Such protein samples can be analysed with mass spectrometry methods. The doctoral thesis of M.Sc. Sami Pietilä studies the feasibility of Data-Independent Acquisition (DIA) mass spectrometry method for the analysis of samples with a large number of different microbes. According to the study, DIA-method is suitable for the analysis of human gut microbiota and it improves the reproducibility of the analysis results compared to the currently used DDA-method.

    In the thesis, DIA-data analysis was demonstrated with a laboratory-assembled mixture of 12 bacterial species as well as with human fecal samples. Two different DIA-data analysis approaches were presented. The first approach used DDA-data to assist the analysis, while the second approach used solely DIA-data. Finally, DIA-data analysis was applied to analyse bacteria originated carbohydrate-active enzymes from gut microbiota.

    As a part of the research project, a data-analysis software for DIA-data was developed and published under an open source licence.

    The thesis has been published online: