Rapid identification of species, sex and maturity by mass spectrometric analysis of animal faeces

Abstract

Background We describe a new approach to the recovery of information from faecal samples, based on the analysis of the molecular signature generated by rapid evaporative ionisation mass spectrometry (REIMS). Results Faecal pellets from five different rodent species were analysed by REIMS, and complex mass spectra were acquired rapidly (typically a few seconds per sample). The uninterpreted mass spectra (signatures) were then used to seed linear discriminant analysis and classification models based on random forests. It was possible to classify each species of origin with a high rate of accuracy, whether faeces were from animals maintained under standard laboratory conditions or wild-caught. REIMS signatures were stable to prior storage of the faecal material under a range of different conditions and were not altered rapidly or radically by changes in diet. Further, within species, REIMS signatures could be used to discriminate faeces from adult versus juvenile mice, male versus female mice and those from three different laboratory strains. Conclusions REIMS offers a completely novel method for the rapid analysis of faecal samples, extending faecal analysis (previously focused on DNA) to an assessment of phenotype, and has considerable potential as a new tool in the armamentarium of the field biologist. Electronic supplementary material The online version of this article (10.1186/s12915-019-0686-9) contains supplementary material, which is available to authorized users.

The application of rapid evaporative ionization mass spectrometry in the analysis of Drosophila species—a potential new tool in entomology

“…Identification of single molecules from the acquired mass spectra is rarely the objective; instead pattern recognition is applied to identify unique mass patterns that facilitate classification and consequently sample identification. REIMS is a novel ionization technique, which has been developed to distinguish cancerous from healthy tissue during cancer surgery (iKnife) [37,38], but has found application in a variety of fields from food security and adulteration detection [39,40] to identification and characterization of bacterial strains [41][42][43] and, most recently, to recover information from rodent and human faecal matter [44,45].…”

Rapid identification of mosquito species, sex and age by mass spectrometric analysis

“…First, because there is zero sample preparation, the generation of the aerosol can be applied to a broad range of biological material, including tissues, [27][28][29], foodstuffs [30][31][32]47], faecal pellets [37],…”

Rapid evaporative ionisation mass spectrometry (REIMS): A potential and rapid tool for the identification of insecticide resistance in mosquito larvae

“…We also compared two different classification model types, linear discriminant analysis (LDA) and random forest (RF) both of which are commonly applied to classification of samples using REIMS data (Cameron et al 2016, St John et al 2017, Davidson et al 2019, Gredell et al 2019, Wagner et al 2020, Sarsby et al 2021). LDA is often the classification method of choice for spectrometry-based phenotyping, including REIMS (Bonetti 2018, D’Hue et al 2018, Gredell et al 2019, Kenar et al 2019, Liu et al 2021, Wang et al 2021).…”

“…The spectra are then are discretised by binning, creating a data matrix that is further processed by dimension reduction and classification (Balog et al 2010). The potential applications of REIMS are vast with its previous successful applications including distinguishing cancerous tissue from healthy tissue (Alexander et al 2017, St John et al 2017, Phelps et al 2018), authentication of food products (Balog et al 2016, Black et al 2017, Verplanken et al 2017, Guitton et al 2018, Rigano et al 2019), microbial species identification (Strittmatter et al 2013, 2014), monitoring of bacterial growth and recombinant protein expression (Sarsby et al 2021), and the identification of rodent species and sex from faecal matter (Davidson et al 2019). REIMS has also been shown to be a highly effective method for species and sex determination in Drosophila adults and larvae (Wagner et al 2020).…”