Biology subjects

Sierocinski, P.

Publications and source records attributed to Sierocinski, P..

3 recordsLinked to original sources

bioRxiv2021

Parallel evolution of phage resistance - virulence trade - offs during in vitro and nasal Pseudomonas aeruginosa phage treatment

With rising antibiotic resistance, there has been increasing interest in treating pathogenic bacteria with bacteriophages (phage therapy). One limitation of phage therapy is the ease at which bacteria can evolve resistance. Negative effects of resistance may be mitigated when resistance results in reduced bacterial growth and virulence, or when phage coevolve to overcome resistance. Resistance evolution and its consequences are contingent on the bacteria-phage combination and their environmental context, making therapeutic outcomes hard to predict. One solution might be to conduct "in vitro evolutionary simulations" using bacteria-phage combinations from the therapeutic context. Overall, our aim was to investigate parallels between in vitro experiments and in vivo dynamics in a human participant. Evolutionary dynamics were similar, with high levels of resistance evolving quickly with limited evidence of phage evolution. Resistant bacteria - evolved in vitro and in vivo - had lower virulence. In vivo, this was linked to lower growth rates of resistant isolates, whereas in vitro phage resistant isolates evolved greater biofilm production. Population sequencing suggests resistance resulted from selection on de novo mutations rather than sorting of existing variants. These results highlight the speed at which phage resistance can evolve in vivo, and in vitro experiments may give useful insights for clinical evolutionary outcomes.

evolutionary biology↗

bioRxiv2021

The impact of invader number on whole community invasions in biomethane-producing communities

Microbes can invade as whole communities, but the ecology of whole community invasions are poorly understood. Here, we investigate how invader frequency affects the composition and function of invaded laboratory methanogenic communities. An invading community was equally successful at establishing itself in a resident community regardless of initial invader frequency, which varied between 0.01 and 10%. Invasion resulted in enhanced biogas production (to the level of the pure invading community), but only when invader frequency was 1% or greater. This inconsistency between invasion success and changes in function can be explained by a lower number of invading taxa (but not individuals) at lower initial invader frequencies, and an important functional role of the taxa that were absent. Our results highlight that whole community invasion ecology cannot simply be extrapolated from our understanding of single species invasions. Moreover, we show that methane production can be enhanced by invading poorly performing reactors with a better performing community at levels that may be practical in industrial settings.

ecology↗

bioRxiv2017

The most efficient microbial community dominates during community coalescence

Microbial communities commonly coalesce in nature, but the consequences for resultant community structure and function is unclear. Consistent with recent theory, we demonstrate using methanogenic communities that the most productive communities in isolation dominated when communities were mixed. As a corollary of this dynamic, total methane production increased with the number of inoculated communities. The cohesion and dominance of single communities was explained by more \"niche-packed\" communities being both more efficient at exploiting resources and resistant to invasion, rather than a function of the average performance of component species. These results are likely to be relevant to the ecological dynamics of natural microbial communities, as well as demonstrating a simple method to predictably enhance microbial community function in biotechnology, health and agriculture.

microbiology↗