Spatially and temporally resolved metabolome of the oral human cavity, negative ionization mode, batch 1

BACKGROUD: Saliva samples (#159) from 20 healthy volunteers, including ten males and ten females was analyzed using a semi-targeted LC-MS/MS platform.
SAMPLE NAMES:
Structure: [polarity]_[batch]_[sample type]_[subject id]_[time of collection]_[oral location]_[injection number].
explanation: Polarity (neg = negative, pos = positive), batch (1, 2), sample type (blank, QC, sample), time (M = morning, A = afternoon, E = evening), oral location (AT = above the tongue, BT = below the tongue, CK = cheek)
Note: When subject id, time of collection, and oral location for blank and QC sample type are equal to 0.
RESULTS: Many the metabolites that exhibit heterogeneous distribution, several important metabolites are linked to oral health, such as N-acetylated metabolites, L-ornithine, saccharides, and guanosine monophosphate. Next to the spatial distribution of metabolites, we identified known and novel time dependencies. Among the novel diurnal metabolites, N-acetyl methionine, N,N,N-trimethyl lysine, and N-acetyl tryptophan revealed diurnal patterns in all oral locations. Where the former two behave similarly to cortisol, and the latter has its nadir in the M. Moreover, a pool of amino acids and mono-phosphorylated nucleotides manifested a significant diurnal rhythm exclusively in BT.