MATRIX: rapid quantification of total and active microbial cells with single-cell phenotypes for environmental...

Area of Science:

• Microbiology and Systems Biology
• Environmental Science and Ecology

Background:

• Current methods for quantifying bacterial populations (e.g., optical density, marker-gene quantification) are indirect, labor-intensive, and cannot differentiate between active and inactive cells.
• Reliance on indirect proxies obscures ecological interpretation and limits mechanistic understanding of microbiome dynamics.

Purpose of the Study:

• To introduce a novel, efficient workflow called microbial activity and total cell quantification via rapid imaging and extraction (MATRIX) for direct quantification of total and redox-active bacterial cells.
• To enable accurate single-cell measurements for environmental bacterial populations and communities, anchoring microbiome data in direct ecological accounting.

Main Methods:

• MATRIX integrates sample extraction, fluorescence staining, automated microscopy and image analysis, and Bayesian statistical inference.
• The workflow quantifies both total bacterial cell counts and redox-active (metabolically active) cells from environmental samples.

Main Results:

• Demonstrated reproducibility and versatility of MATRIX using cultured bacterial isolates and high-diversity soil microbial communities.
• Generated quantitative, phenotypic single-cell data sets providing direct measurements of bacterial population and community size and activity.

Conclusions:

• MATRIX offers a rapid and efficient method to incorporate quantitative ecology into systems microbiology and microbiome studies.
• The workflow strengthens mechanistic insight into microbial responses to environmental changes and improves the ecological grounding of microbiome research.