Metadata is information about data. Making a metadata file is a standard and repetitive step in a bioinformatician’s day-to-day workflow who deals with metabolomics data. While performing the mass spectrometry experiment in a metabolomics lab, the bioinformatician inputs samples’ relative concentration in the machine. Its output is fed to tools like El-MAVEN or Multiquant which are responsible for mapping out intensities for those samples.
But to perform some downstream analyses like Kinetic Flux Analysis, they need absolute concentrations of unknown samples/biosamples. That’s where Polly QuantFit comes in handy.
Polly QuantFit is a cloud-based app which helps in absolute quantification of metabolites. Standard/known samples are mapped as Intensities to concentrations to get the best curve fit. Unknown samples are then mapped to this curve to obtain their concentrations.
Standard Metadata helps us understand two things-
a. Among all samples, which samples are the standard samples?
b. What is the concentration of all the metabolites in all standard samples?
For a typical metabolomic dataset, the number of samples and metabolites is as given in Fig 4.
Once the user has identified the standard samples, the next step is to fill their concentrations in an excel file.
Now, let’s do some maths to understand what it means for a user in two scenarios:
a. Best Case — 5 standard samples and 100 metabolites
Number of cells to be filled — 5 * 100 = 500
b. Worst case — 10 standard samples and 500 metabolites
Number of cells to be filled — 10 * 500 = 5000
Clearly, the problem here is the time, complexity and possibility of error in manually filling 5000 cells in an excel sheet for one dataset.
a. Select and move standard samples
Polly autodetects the samples which have the general nomenclature of std/STD prepended in the name as standard samples. Also, it lets user select and move the samples to either of the lists if some sample is missed or if a user follows a different naming convention.
b. Fill ConcentrationThe next step is to fill the concentration for all the metabolites.
This step is different from filling concentrations in excel file in three ways –
Polly has reduced the time and UX complexity of filling 5000 cells in an excel sheet to just a few clicks.
b. The work is being done to implement the interface for MS/MS data as well.
c. We will continue to work on some critical insights gained from our users on further user experience enhancement.
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