# Leveraging Dissolved Organic Matter Collections as a Natural Chemical Library to Link Molecular Traits with Cellular Morphological Responses

## TL;DR

This study explores how dissolved organic matter affects cell shape, linking chemical traits to biological effects using advanced analysis methods.

## Contribution

The novel integration of FT-ICR MS and Cell Painting assays to connect DOM molecular traits with cellular morphological responses.

## Key findings

- Humic acids show stronger aliphatic and aromatic traits, while fulvic acids and NOM are more oxidized.
- Hydrophobic humic substances induce significant morphological changes in cells.
- Lipid-like and nitrogen-rich aromatic compounds are likely responsible for observed cellular effects.

## Abstract

Dissolved organic
matter (DOM) exhibits a highly complex molecular
composition and maintains ecosystem stability, acting as a crucial
interface between biotic and abiotic processes. Although DOM’s
molecular complexity and biological effects are widely studied, most
investigations use targeted bioassays, examining specific responses
and linking molecular features only to predefined biological outcomes
when assessing potential bioactive components. Here, we analyzed International
Humic Substances Society (IHSS) reference standards of natural organic
matter (NOM) and humic fractions, including humic acids (HAs) and
fulvic acids (FAs), using ultrahigh resolution Fourier- transform
ion cyclotron resonance mass spectrometry (FT-ICR MS) alongside the
Cell Painting (CP) assay, a multiplexed, image-based morphological
profiling method. The chemical composition of IHSS samples was influenced
by fractionation methods and environmental sources. HAs exhibited
stronger aliphatic and aromatic characteristics, whereas FAs and NOM
extracted by reverse osmosis were more oxidized. Distinct molecular
patterns were observed among terrestrial HAs, Pony Lake FAs, terrestrial
FAs, and other fractions. In the CP assay, the most hydrophobic humic
substances induced the most pronounced morphological changes. Linking
chemical features with morphological outcomes suggested lipid-like
compounds and nitrogen-rich aromatic species as likely contributors.
This integrative approach provides preliminary molecular leads for
further isolation, structural characterization, and mechanistic studies
of DOM bioactivity.