Seminario: Stable isotopes in Microbiology: from activity to function.

Seminario organizato nell'ambito dei Corsi di Dottorato in Molecular and Cell Biology, e Earth, Life and Environmental Sciences.

ABSTRACT
Microbial communities are extraordinarily diverse, but identifying which microorganisms are active 
and determining what they are actually doing remains a major challenge in microbiology. Stable 
isotopes provide a powerful set of tools to move beyond measurements of microbial presence or 
abundance and directly trace biological processes. In this seminar, I will introduce the principles of 
stable isotope tracing and illustrate how different isotopes can be used to investigate microbial 
activity, growth and metabolism. Examples will include the use of 13C and 15N to follow substrate 
utilization and elemental transformations, 18O incorporation into DNA to quantify microbial growth, 
and deuterated water as a tracer of microbial biosynthesis. I will also discuss stable isotope probing 
approaches that combine isotope incorporation with biomarkers or molecular techniques to identify 
the organisms responsible for particular processes. Most examples will come from soil microbial 
ecology, where complex and highly diverse communities provide an ideal testing ground for these 
approaches, but the underlying concepts are broadly applicable across microbial systems. 
Particular attention will be given to how isotope approaches can complement sequencing and other 
omics techniques, allowing microbial identity to be linked to activity and function. Finally, I will 
discuss some of the methodological challenges, assumptions and opportunities associated with 
these approaches.
BIOGRAPHICAL SKETCH
Alberto Canarini is Associate Professor at the Department of Biological, Geological and 
Environmental Sciences of the University of Bologna. His research focuses on microbial ecology and 
biogeochemistry, with particular interest in understanding how microorganisms regulate carbon and 
nutrient cycling and respond to environmental change. A major component of his work is the 
development and application of stable isotope approaches to quantify microbial activity and growth. 
He has worked extensively with 13C, 15N, 18O and 2H tracers, combining isotope measurements 
with microbial biomarkers and molecular approaches. His research has particularly explored 
microbial responses to drought and other environmental perturbations, using soils as model 
complex microbial ecosystems. He is currently Principal Investigator of the ERC Starting Grant 
EcoMEMO, which investigates how recurrent drought shapes microbial ecological memory and 
ecosystem functioning. His broader research interests include microbial physiology, stable isotope 
probing, biogeochemical cycling and the integration of process-based measurements with microbial 
community analyses.