Biology subjects

Avignone Rossa, C.

Publications and source records attributed to Avignone Rossa, C..

3 recordsLinked to original sources

bioRxiv2022

Microbial electrochemical systems for enhanced degradation of glyphosate: Electrochemical performance, degradation efficiency, and analysis of the anodic microbial community

Glyphosate, one of the most used herbicides worldwide, is known as an aquatic contaminant of concern, and can present adverse impacts in agroecosystems. In this study, we investigated the degradation of glyphosate in microbial electrochemical systems (MESs), and analysed the microbial composition of enriched anodic biofilms, and comparing them with microbial communities of non-MESs enriched cultures. MESs supported higher glyphosate degradation (68.41 {+/-} 1.21 % to 73.90 {+/-} 0.79 %) compared to non-MESs cultures (48.88 {+/-} 0.51 %). The Linear Sweep Voltammetry (LSV) analysis showed that MESs operated at +300 mV, produced a maximum current of 611.95 A, which was the highest among all the applied voltages. 16S amplicon sequencing revealed a significant difference in microbial community composition of MESs anodic biofilms and non-MESs enriched communities. The anodic biofilms were dominated by Rhodococcus (51.26 %), Pseudomonas (10.77 %), and Geobacter (8.67 %) while in non-MESs cultures, methanogens including Methanobrevibacter (51.18 %), and Methanobacterium (10.32 %), were the dominant genera. The present study suggested that MESs could be considered as a promising system for glyphosate degradation.

microbiology↗

bioRxiv2020

The loss of the pyoverdine secondary receptor in Pseudomonas aeruginosa results in a fitter strain suitable for population invasion

The rapid emergence of antibiotic resistant bacterial pathogens constitutes a critical problem in healthcare and requires the development of novel treatments. Potential strategies include the exploitation of microbial social interactions based on public goods, which are produced at a fitness cost by cooperative microorganisms, but can be exploited by cheaters that do not produce these goods. Cheater invasion has been proposed as a Trojan horse approach to infiltrate pathogen populations with strains deploying built-in weaknesses (e.g. sensitiveness to antibiotics). However, previous attempts have been often unsuccessful because population invasion by cheaters was prevented by various mechanisms including the presence of spatial structure (e.g. growth in biofilms), which limits the diffusion and exploitation of public goods. Here we followed an alternative approach and examined whether the manipulation of public good uptake and not its production could result in potential Trojan horses suitable for population invasion. We focused on the siderophore pyoverdine produced by the human pathogen Pseudomonas aeruginosa MPAO1 and manipulated its uptake by deleting and/or overexpressing the pyoverdine primary (FpvA) and secondary (FpvB) receptors. We found that receptor synthesis feeds back on pyoverdine production and uptake rates, which led to strains with altered pyoverdine-associated costs and benefits. Moreover, we found that the receptor FpvB was advantageous under iron-limited conditions but revealed hidden costs in the presence of an antibiotic stressor (gentamicin). As a consequence, FpvB mutants became the fittest strain under gentamicin exposure, displacing the wildtype in liquid cultures, and in biofilms and during infections of the wax moth larvae Galleria mellonella, which both represent structured environments. Our findings reveal that an evolutionary trade-off associated with the costs and benefits of a versatile pyoverdine uptake strategy can be harnessed for devising a Trojan horse candidate for medical interventions.

microbiology↗

bioRxiv2018

Disturbance During Biofilm Community Succession Promotes Cooperation and Diversity

Diversity-disturbance relationships have found widespread application in ecology, conservation and biodiversity management. In spite of their explanatory power, these conceptual frameworks have yet to be systematically applied to understanding succession in diverse microbial biofilms. Here we investigate community assembly in biofilms formed in replicate microbial bioelectrochemical systems using time-course sequencing of community 16S rRNA genes, corresponding to hundreds of operational taxonomic units (OTUs). For the first time we present a statistical model showing that a simple diversity-disturbance relationship can be used to explain dynamic changes in high diversity biofilm communities. This simple model reveals that succession in these systems is guided towards either a low diversity, generalist-dominated biofilm or a high diversity, cooperative-specialist biofilm, depending on the level of endogenous disturbance measured within the community. The pattern observed shows remarkable symmetry with findings from macro-scale communities such as grasslands, forests and coral reefs.

ecology↗