Method for generation and use of isotopic patterns in mass spectral data of simple organisms

A method for identifying an analyte of a biological sample that is affected by a stressor comprising the steps of:

• (a) providing a composite biological organism sample that is comprised of two admixed substantially identical samples of biological organisms that are a control sample and an experimental sample, wherein said control sample organisms had been grown in a first nutrient medium containing predetermined amounts of first and second isotopes of a first atom within a nutrient, and said experimental sample was grown in a second nutrient medium substantially identical to said first nutrient medium but containing different predetermined amounts of said first and second isotopes of said first atom within said nutrient compared to said first nutrient medium, said first and second isotopes being other than H or D, said experimental sample being cultured with a stressing regimen containing a stressing agent for a time period sufficient for said sample to grow and said control sample being cultured for a time period sufficient for the control sample to grow with a regimen substantially identical to the stressing regimen but lacking the stressing agent and maintaining said regimen;
• (b) mass spectroscopically analyzing said composite biological organism sample for analyte peaks;
• (c) determining the ratio of first isotope to second isotope for each analyzed analyte peak;
• (d) determining the composite biological organism sample median isotopic ratio;
• and
• (e) comparing the ratio of first isotope to second isotope for each analyzed analyte peak with the composite biological sample median isotopic ratio, an analyte whose isotopic ratio significantly deviates from the composite biological sample median isotopic ratio being an analyte affected by the stressing agent.

A method for identifying an analyte of a biological sample that is affected by a stressor comprising the steps of:

• (a) providing a composite biological organism sample that is comprised of two substantially identical samples of biological organisms that are a control sample and an experimental sample and are admixed in substantially equal amounts, wherein said control sample organisms were grown in a first nutrient medium and said experimental sample was grown in a second nutrient medium, wherein said first and second nutrient media were substantially identical except that said second nutrient medium contains a nutrient that has different predetermined amounts of first and second isotopes of a first atom within said nutrient compared to amounts of first and second isotopes of a first atom within said first nutrient medium, wherein said predetermined first and second isotope amounts are present in inverted ratios of each other such that the number of the numerator of the first ratio is the number of the denominator of the second ratio, and the number of the denominator of the first ratio is the number of the numerator of the second ratio, said first and second isotopes being other than H or D, said experimental sample being cultured with stressing regimen containing a stressing agent for a time period sufficient for said sample to grow and said control sample being cultured for a time period sufficient for the control sample to grow with a regimen substantially identical to the stressing regimen but lacking the stressing agent;
• (b) mass spectroscopically analyzing said composite biological organism sample for analyte peaks;
• (c) determining the ratio of first isotope to second isotope for each analyzed analyte peak as well as for one or more of analyte peaks M+1, M+2, M−1, and M−2;
• (d) determining the composite biological organism sample median isotopic ratio;
• and
• (e) comparing the ratio of first isotope to second isotope for each analyzed analyte peak with the composite biological sample median isotopic ratio, an analyte whose isotopic ratio significantly deviates from the composite biological sample median isotopic ratio being an analyte affected by the stressing agent.

A method for identifying an analyte of a biological sample that is affected by a stressor comprising the steps of:

• (a) providing a composite biological organism sample that is comprised of two substantially identical samples of biological organisms that are a control sample and an experimental sample and are admixed in substantially equal amounts, wherein:
• (i) said control sample organisms were grown in a first nutrient medium and said experimental sample organisms were grown in a second nutrient medium,
• (ii) said first and second nutrient media were substantially identical except that said second nutrient medium contained a nutrient that contains 90% to 95% of 12C, and the other of said first and second nutrient media contains that nutrient having 90% to 95% of 13C, wherein said 12C and 13C isotope amounts are present in inverted ratios of each other such that the number of the numerator of the first ratio is the number of the denominator of the second ratio, and the number of the denominator of the first ratio is the number of the numerator of the second ratio, and
• (iii) said experimental sample was cultured with a stressing regimen containing a stressing agent for a time period sufficient for said sample to grow and said control sample was cultured for a time period sufficient for the control sample to grow with a regimen substantially identical to the stressing regimen but lacking the stressing agent;
• (b) mass spectroscopically analyzing said composite biological organism sample for analyte peaks;
• (c) determining the ratio of 12C to 13C for each analyzed analyte peak including one or more analyte peaks selected from the group consisting of M+1. M+2, M+3, M+4, M+5, M−1, M−2, M−3, M−4 and M−5;
• (d) determining the composite biological organism sample median isotopic ratio;
• and
• (e) comparing the ratio of 12C to 13C for each analyzed analyte peak with the composite biological sample median isotopic ratio, an analyte whose isotopic ratio significantly deviates from the composite biological sample median isotopic ratio being an analyte affected by the stressing agent.