Biology subjects

Moreno-Gamez, S.

Publications and source records attributed to Moreno-Gamez, S..

4 recordsLinked to original sources

bioRxiv2026

Temporal resource variation promotes growth equalization through alternative plasticity strategies

Evolutionary theory predicts that fluctuating environments favor adaptations that maximize geometric-mean fitness by reducing variance in performance across conditions. We tested this prediction experimentally by evolving the lactic acid bacterium Lactococcus cremoris on the sugars fructose and galactose in density-controlled chemostats under four resource regimes: constant supply of fructose, constant supply of galactose, a constant mixture of both sugars, and a temporally alternating supply of the two. In the absence of temporal variation, trade-offs between fructose and galactose resulted in evolutionary divergence into a fructose specialist and a galactose specialist. In contrast, adaptation to temporal resource variation equalised growth performance on both sugars by increasing its growth rate on galactose and decreasing it on fructose. Interestingly, performance equalization emerged across replicate populations through distinct resource-transition strategies, indicated by differences in resource affinity and growth recovery on fructose and galactose among strains isolated from the evolved populations. Our results show that temporal resource variation selects for variance-minimizing resource adaptations while adopting multiple resource transition strategies, illustrating how distinct modes of metabolic plasticity can yield convergent fitness outcomes.

evolutionary biology↗

bioRxiv2025

Niche partitioning by resource size in the gut microbiome

Niche partitioning promotes diversity of the human gut microbiota. However, the molecular basis of resource specialization and niche separation in the gut remains poorly understood. Here we show that structural differences in glycan transporters drive members of the genus Bacteroides, common human gut commensals, to specialize on distinct chain lengths of the same fructan molecule. While species encoding canonical SusCD systems for glycan import -formed by a membrane-embedded barrel capped with a lipoprotein lid- specialized in long-chain fructans, species with smaller lidless transporters, not previously described in Bacteroides, specialized in short-chain fructans. Strikingly, we found that a [~]140-amino acid domain in the SusC barrel is a structural feature that governs substrate preference: deleting it does not impair transport but instead shifts uptake preferences from long-to short-chain fructans. These structural differences predict competitive outcomes in vivo on fructans of varying lengths, suggesting that glycan uptake mechanisms shape ecological niches in the gut and can inform fiber-based dietary interventions. Similar small lidless transporters exist across the Bacteroidota, expanding the paradigm of glycan utilization in this phylum beyond the canonical SusCD architecture.

microbiology↗

bioRxiv2025

A universal surface functionalization technique to chemically enhance live microbial cells

Microbial surface functionalization is a powerful strategy for endowing microbes with novel, non-genetic functions. However, existing methods are often species-specific, limited in scope, and compromise cell viability. Here, we present a universal and modular platform for high-density, reproducible surface functionalization across diverse microbial species--including Gram-positive, Gram-negative, aerobic, and anaerobic bacteria--using multiple molecular classes such as fluorophores, enzymes, and nucleic acids. Our method preserves cell viability, and achieves 50x higher functionalization efficiency than previous methods with a standardized protocol applicable to any azide-containing molecule. Applications of the method show reproducible and tunable phenotypic outcomes at the single-cell level: fluorophore labeling yielded adjustable fluorescence, {beta}-lactamase conferred scalable antibiotic resistance, and DNA coatings modulated adhesion and aggregation. This platform provides quantitative, non-genetic control over microbial phenotypes and complements genetic engineering approaches. It enables new possibilities for microbial design in biotechnology, medicine, and environmental applications where genetic modification is impractical or undesirable.

microbiology↗

bioRxiv2022

Quorum sensing as a mechanism to harness the wisdom of the crowds

Bacteria release and sense small molecules called autoinducers (AIs) in a process known as quorum sensing (QS). The prevailing interpretation of QS is that by sensing AI concentrations, bacteria estimate population density to regulate the expression of functions that are only beneficial when carried out by a sufficiently large number of cells. However, a major challenge to this interpretation is that the concentration of AIs strongly depends on the environment, often rendering AI-based estimates of cell density unreliable. Here we propose an alternative interpretation of QS, where bacteria, by releasing and sensing AIs, harness social interactions to sense the environment as a collective. As shown by a model, this functionality can explain the evolution of QS, and results from individuals improving their estimation accuracy by pooling many imperfect estimates - analogous to the wisdom of the crowds in decision theory. Importantly, our model reconciles the observed dependence of QS on both population density and the environment and explains why several QS systems regulate the production of private goods.

microbiology↗