Generation and use of isotopic patterns in phenotypic comparison of mass spectra of organisms

摘要

A method for testing phenotypic similarity or dissimilarity of a tested organism compared to that of a standard organism of the same species comprising the steps of: (a) providing a composite sample comprising a mixture of substantially equal amounts of the first and second samples, said first sample being a standard sample comprising average concentrations of a majority of constituent compounds having a molecular mass of less than 1000 amu (Da) that are present in a representative sample of the organism species whose phenotype is to be tested. , said constituent compounds (i) being dissolved or dispersed in a first liquid medium and (ii) each constituent compound comprising the same first predetermined amounts of the first and second stable isotopes of a first atom, said second sample being a test sample comprising constituent compounds that have a molecular mass less than 1000 uma that are present in a representative sample of the organism whose phenotype is to be tested, said constituent compounds (i) being dissolved or dispersed in a second liquid medium and (ii) each constituent compound being comprised of the same second quantities predetermined of the first and second stable isotopes of said first atom, said first and second predetermined amounts of the first and second isotopes being different from each other, and said first and second isotopes other than H or D; (b) analyze by mass spectroscopy said composite sample for analytes; (c) determine the ratio of the first isotope to the second isotope for each analyte analyzed; (d) determine the isotopic ratio of the median of the composite sample; and (e) compare the ratio of the first isotope with respect to the second isotope for each analyte analyzed with the isotopic ratio of the median of the composite sample, being a tested organism whose analyzed isotopic ratios deviate statistically significantly from the analyzed isotopic ratios. of the median of the sample of phenotypically different composite material of the standard organism, and being a tested organism whose analyzed isotopic ratios do not deviate statistically significantly from the analyzed ionic isotopic ratios of the median of the sample of phenotypically similar composite material to the standard organism.