Changes in interactions over ecological time scales influence single-cell growth dynamics in a metabolically coupled marine microbial community

Abstract

Microbial communities thrive in almost all habitats on earth. Within these communities, cells interact through the release and uptake of metabolites. These interactions can have synergistic or antagonistic effects on individual community members. The collective metabolic activity of microbial communities leads to changes in their local environment. As the environment changes over time, the nature of the interactions between cells can change. We currently lack understanding of how such dynamic feedbacks affect the growth dynamics of individual microbes and of the community as a whole. Here we study how interactions mediated by the exchange of metabolites through the environment change over time within a simple marine microbial community. We used a microfluidic-based approach that allows us to disentangle the effect cells have on their environment from how they respond to their environment. We found that the interactions between two species—a degrader of chitin and a cross-feeder that consumes metabolic by-products—changes dynamically over time as cells modify their environment. Cells initially interact positively and then start to compete at later stages of growth. Our results demonstrate that interactions between microorganisms are not static and depend on the state of the environment, emphasizing the importance of disentangling how modifications of the environment affects species interactions. This experimental approach can shed new light on how interspecies interactions scale up to community level processes in natural environments.

Interspecies interactions determine growth dynamics of biopolymer degrading populations in microbial communities

“…We found that ZF270 cells in coculture with 1F187 cells had higher alginate lyase activity than ZF270 cells in monoculture. A similar observation has been made in the case of increased expression of chitinases by Vibrio natrigens in response to crossfeeding by Alteromonas macleodii cells (27). We speculate that increased alginate lyase activity combined with competition for oligomeric breakdown products between ZF270 and 1F187 cells causes a shift in the growth dynamics of ZF270 cells (Figure 4).…”

“…A possible explanation for how cross-feeder cells influence the growth of degrader cells is through the production or consumption of secreted metabolites(11, 13, 23–27). Cross-feeders can decrease the growth of degraders by consuming metabolites that represent nutrients for degraders, thus reducing the availability of these for degraders, or by producing metabolites that inhibit the growth of degraders(26, 28).…”

“…A possible explanation for how cross-feeder cells influence the growth of degrader cells is through the production or consumption of secreted metabolites (11,13,(23)(24)(25)(26)(27).…”

Microfluidic approaches in microbial ecology

“…144 Microfluidics also allows the analysis of the interactions within communities composed of naturally occurring strains to explore the effects of these interactions on community dynamics. 156,157 For example, a recent study Fig. 4 Microfluidic approaches to quantify the interaction distance among microbial cells.…”

Microbial Gladiators: Unraveling the dynamics of carbon substrate competition among heterotrophic microbes

“…Microbial interactions are inherently dynamic, continuously shaped by their surrounding environment and the intricate interplay among microbes [14, 15]. The competitive exclusion principle of ecology, often referred to as Gause’s Law, asserts that in stable environmental conditions, when two species compete for the same resource, even a slight advantage will eventually result in the dominance of the better competitor, leading to the extinction of the inferior species or its adaptation to a new, non-competitive niche [16].…”