Biology subjects

Erdos, Z.

Publications and source records attributed to Erdos, Z..

4 recordsLinked to original sources

bioRxiv2026

Antimicrobial resistance in a warmer world: selection and transfer of kanamycin resistance is temperature dependent in E. coli.

Climate warming consistently correlates with increased antimicrobial resistance (AMR). Understanding the biological mechanisms underpinning this relationship is important for both prediction and mitigation of the future burden of antibiotic resistance in a warmer world, especially given AMR can spread through both selection and horizontal gene transfer. Here, we experimentally measure how temperature alters susceptibility to kanamycin, selection and spread of resistance in Escherichia coli MG1655 carrying the natural plasmids R1 and RP4. We predict that susceptibility should be lowest - and plasmid transfer highest - at maximal growth rate. Thermal performance of bacterial growth peaked at 40{degrees}C and we detected a small plasmid cost - for RP4, but not R1 - in the absence of kanamycin. The thermal performance of plasmid transfer did not mirror that of bacterial growth, instead, R1 transfer peaked at 35{degrees}C with a much narrower thermal tolerance. Susceptibility to kanamycin decreased with increasing growth rate until 31{degrees}C, before increasing again as temperatures approached and exceeded optimal growth temperature. Increasing susceptibility coupled with high growth rates meant that selection was strongest at the highest measured temperature, but the shape of the relationship changed with kanamycin concentration. In mixed populations of resistant and susceptible bacteria, we found that AMR spread most where selection was strongest, irrespective of plasmid transfer. Our findings suggest increased AMR at higher temperatures is predominantly driven by higher growth rates and increased susceptibility, resulting in stronger selection. Our study provides a framework to uncover generalities across antibiotic classes, strains, species, and plasmids, laying the foundation for improved prediction of AMR selection in the environment.

microbiology↗

bioRxiv2025

Community complexity does not weaken pairwise coevolution in a soil bacterial community

Exploitative interactions, such as predator-prey and host-parasite interactions, are ubiquitous in microbial communities. These interactions shape community density and composition, imposing strong selection on members to evolve countermeasures reducing the negative impacts of exploitation. Exploitative coevolution is often studied between species pairs in isolation, which may over-estimate the strength and relevance of pairwise coevolution. Here we studied how community context influences coevolution between Pseudomonas fluorescens (exploited) and Variovorax sp. (exploiter). We evolved these species in pairwise coculture and embedded within a five-species community to investigate evolved changes in pairwise interactions. We found evidence for asymmetrical coevolution: Variovorax evolved more rapidly than Pseudomonas, leading to increased exploitation through time, while Pseudomonas evolved increased tolerance to Variovorax with time lag. The pairwise coevolutionary dynamics were not affected by the presence of other community members. Understanding how coevolutionary patterns change with increasing community complexity can have important implications for community persistence and function.

evolutionary biology↗

bioRxiv2023

Manipulating multi-level selection in a fungal entomopathogen reveals social conflicts and a method for improving biocontrol traits

Changes in parasite virulence are commonly expected to lead to trade-offs in other life history traits that can affect fitness. Understanding these trade-offs is particularly important if we want to manipulate the virulence of microbial biological control agents. Theoretically, selection across different spatial scales, i.e. between- and within-hosts, shapes these trade- offs. However, trade-offs are also dependent on parasite biology. Despite their applied importance the evolution of virulence in fungal parasites is poorly understood: virulence can be unstable in culture and commonly fails to increase in simple passage experiments. We hypothesized that manipulating selection intensity at different scales would reveal virulence trade-offs in a fungal pathogen of aphids, Akanthomyces muscarius. Starting with a genetically diverse stock we selected for infectivity, parasite yield or speed of kill by manipulating competition within and between hosts and between groups of hosts over 7 rounds of infection. We characterized ancestral and evolved lineages by whole genome sequencing and by measuring virulence, growth rate, sporulation and fitness. While several lineages showed increases in virulence, we saw none of the trade-offs commonly found in obligately-killing parasites. Phenotypically similar lineages within treatments often shared multiple single-nucleotide variants, indicating strong convergent evolution. The most dramatic phenotypic changes were in timing of sporulation and spore production in vitro. We found that early sporulation led to reduced competitive fitness but could increase yield of spores on media, a trade-off characteristic of social conflict. Notably, the selection regime with strongest between-group competition and lowest genetic diversity produced the most consistent shift to early sporulation, as predicted by social evolution theory. Mutli-level selection therefore revealed social interactions novel to fungi and showed that these biocontrol agents have the genomic flexibility to improve multiple traits -virulence and spore production - that are often in conflict in other parasites. Author summaryUnderstanding the ecological forces that shape virulence is a key challenge in evolutionary biology. Here we investigated how competition at different levels of selection (within-hosts, between-hosts, between populations) could alter investment in virulence in a fungal entomopathogen. We predicted that cooperative investment in virulence would increase at higher scales of competition and aimed to further our understanding of potential trade-offs shaping life-history of a fungal insect pathogens. We found moderate increases in virulence in different selection regimes but importantly, none of the commonly expected trade-offs, such as that between spore production and virulence or a relationship between virulence and growth rate, which is consistent with cooperation. However, we found convergent genetic changes and significant differences in timing and production of spores, dependent how we manipulated scales of selection. Our data suggests that this is driven by social conflict regarding the timing of sporulation. This carries fundamental importance for understanding how varying selection pressure at different scales shape pathogen life history. In addition, these results also have applied importance for understanding how to improve and select for beneficial traits in biocontrol agents.

evolutionary biology↗

bioRxiv2020

Laboratory sprayer for testing of microbial biocontrol agents: design and calibration

The lack of commercially available low-cost laboratory spraying equipment for testing microbial control agents can hinder advancement in the field of biocontrol. This study presents an inexpensive, portable sprayer that is calibrated utilizing laboratory consumables. The computer aided design files are made available so that it is freely modifiable and can be used for machine routing or 3D printing. Bioassay data was obtained by spraying Myzus persicae with spores of entomopathogenic fungi. Observed variation in droplet deposition within tested pressure and volume settings, and spore deposition within sprayed concentrations were low. Bioassay results show reproducible mortality for the tested doses.

microbiology↗