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Frontiers in Cellular and Infection... 2022Antagonistic coevolution between hosts and parasites, the reciprocal evolution of host resistance and parasite infectivity, has important implications in ecology and...
Antagonistic coevolution between hosts and parasites, the reciprocal evolution of host resistance and parasite infectivity, has important implications in ecology and evolution. The dynamics of coevolution-notably whether host or parasite has an evolutionary advantage-is greatly affected by the relative amount of genetic variation in host resistance and parasite infectivity traits. While studies have manipulated genetic diversity during coevolution, such as by increasing mutation rates, it is unclear how starting genetic diversity affects host-parasite coevolution. Here, we (co)evolved the bacterium SBW25 and two bacteriophage genotypes of its lytic phage SBW25ɸ2 in isolation (one phage genotype) and together (two phage genotypes). Bacterial populations rapidly evolved phage resistance, and phage reciprocally increased their infectivity in response. When phage populations were evolved with bacteria in isolation, bacterial resistance and phage infectivity increased through time, indicative of arms-race coevolution. In contrast, when both phage genotypes were together, bacteria did not increase their resistance in response to increasing phage infectivity. This was likely due to bacteria being unable to evolve resistance to both phage the same mutations. These results suggest that increasing initial parasite genotypic diversity can give parasites an evolutionary advantage that arrests long-term coevolution. This study has important implications for the applied use of phage in phage therapy and in understanding host-parasite dynamics in broader ecological and evolutionary theory.
Topics: Bacteriophages; Biological Evolution; Genotype; Host-Parasite Interactions; Pseudomonas Phages; Pseudomonas fluorescens
PubMed: 35310856
DOI: 10.3389/fcimb.2022.834406 -
Food Research International (Ottawa,... May 2022This study investigated the synergistic efficacy of ultrasound (US, 50 kHz, 400 W) in combination with chlorogenic acid (CA; 0, 0.5, 1, and 2%) to inactivate...
This study investigated the synergistic efficacy of ultrasound (US, 50 kHz, 400 W) in combination with chlorogenic acid (CA; 0, 0.5, 1, and 2%) to inactivate Pseudomonas fluorescens planktonic and biofilm cells. The P. fluorescens planktonic and biofilm cells were treated with CA with and without US for 5, 10, 20, 30, or 60 min. Results showed that US enhanced the efficacy of CA for inactivation of both P. fluorescens planktonic and biofilm cells. Treatment with 2% CA and US could completely inactivate P. fluorescens planktonic cells within 10 min and the biofilm cells within 30 min. Confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), ATP, and nucleic acid release assays indicated that the combination of US and CA could quickly damage the integrity of P. fluorescens planktonic and biofilm cell membranes. The combined treatment effectively inactivates P. fluorescens planktonic and biofilm cells via the synergetic destruction of the biofilm structure and bacterial cell integrity.
Topics: Biofilms; Chlorogenic Acid; Microscopy, Electron, Scanning; Plankton; Pseudomonas fluorescens
PubMed: 35400420
DOI: 10.1016/j.foodres.2022.111009 -
Journal of Agricultural and Food... Nov 2021Preharvest application of biocontrol agents is a promising strategy for promoting biosynthesis and accumulation of functional ingredients in fruit crops. In this study,...
Preharvest application of biocontrol agents is a promising strategy for promoting biosynthesis and accumulation of functional ingredients in fruit crops. In this study, we sought to evaluate the potential of ZX in stimulating the primary and secondary metabolism of citrus fruit peel. Pretreatment with ZX was found to significantly affect the concentrations and profiles of both primary and secondary metabolites. More importantly, using ZX suspension to increase inoculation numbers during fruit development typically elicited stronger stimulus effects, and multiple applications of ZX significantly improved the biosynthesis process of beneficial compounds, resulting in their abundant accumulation in the peel. In fruit pretreated four times with ZX, hesperidin, sinensetin, nobiletin, synephrine, and pectin were increased by approximately 26.0, 31.3, 44.8, 19.7, and 23.1%, respectively, compared to the untreated control. Collectively, these results indicated that, as a biostimulant, preharvest application of ZX is an effective, affordable, ecological, and ecofriendly alternative agricultural technique for exploiting citrus crops. This approach is also promising for increasing the value of citrus fruit peel (currently regarded primarily as processing waste), thereby allowing industrial agricultural practices to move one step closer toward a circular economy.
Topics: Citrus; Fruit; Hesperidin; Pseudomonas fluorescens; Secondary Metabolism
PubMed: 34751564
DOI: 10.1021/acs.jafc.1c05709 -
ACS ES&T Water Nov 2023This study assesses the efficacy of ultraviolet light-emitting diodes (UV LEDs) for deactivating (pure culture) and (pure culture and biofilms) on relevant drinking...
This study assesses the efficacy of ultraviolet light-emitting diodes (UV LEDs) for deactivating (pure culture) and (pure culture and biofilms) on relevant drinking water distribution system surfaces (cast iron and stainless steel). UV LED treatment at 280 nm demonstrated superior performance compared to that at 365 nm, achieving a 4.8 log reduction value (LRV) for pure cultures and, for biofilms, 4.02 LRV for stainless steel and 2.96 LRV for cast iron at 280 nm. Conversely, the results were less effective at 365 nm, with suspected photolytic reactions on cast iron. Quantification of yielded varying results: 4 LRV using standard plate counts, 1.8 LRV with Legiolert, and 1 LRV with quantitative polymerase chain reaction at 280 nm, while the results were less than 1.5 LRV at 365 nm. This study provides insights into managing opportunistic pathogens and biofilms, emphasizing the need for improved quantification tools to better assess treatment efficacy.
PubMed: 37970541
DOI: 10.1021/acsestwater.3c00428 -
Journal of Applied Microbiology Jun 2023The aim of this study was to determine the biofilm-forming ability of a strain belonging to the Pseudomonas fluorescens group isolated from the dairy environment under...
AIMS
The aim of this study was to determine the biofilm-forming ability of a strain belonging to the Pseudomonas fluorescens group isolated from the dairy environment under food-relevant conditions. Moreover, the effects of commercial sanitizers against preformed biofilms were assessed both in terms of viability and structure.
METHODS AND RESULTS
The biofilms were formed on polystyrene, stainless steel (SS), and polytetrafluoroethylene (PTFE) in a wide range of temperatures (4-25°C) and were subjected to the action of 10 different sanitizers. The strain under study showed to be a strong biofilm-former regardless of temperature, particularly on polystyrene. The biofilms were mostly sensitive to chlorine and peracetic acid-based sanitizers. For some sanitizers (e.g. amphoteric), a relationship was observed between the material and the tolerance, while the temperature was not statistically significant. The formation of long-term biofilms on SS was also structurally affected by the temperature, showing microcolonies more irregular in shape and with lower cellularity at 4°C compared to 15°C, where the biofilm was more compact and with a high presence of EPS.
CONCLUSIONS
The strain belonging to the P. fluorescens group was shown to quickly adhere and form mature biofilm at temperatures and on materials relevant to the food sector; however, biofilms formed under different conditions were differently tolerant to disinfectants.
SIGNIFICANCE AND IMPACT OF THE STUDY
Findings from this study could provide a basis for developing targeted sanitation protocols in food plants.
Topics: Bacterial Adhesion; Pseudomonas fluorescens; Pseudomonas; Polystyrenes; Biofilms; Disinfectants; Stainless Steel
PubMed: 37279902
DOI: 10.1093/jambio/lxad117 -
MBio Feb 2021Plants form commensal associations with soil microorganisms, creating a root microbiome that provides benefits, including protection against pathogens. While bacteria...
Plants form commensal associations with soil microorganisms, creating a root microbiome that provides benefits, including protection against pathogens. While bacteria can inhibit pathogens through the production of antimicrobial compounds , it is largely unknown how microbiota contribute to pathogen protection . We developed a gnotobiotic model consisting of Arabidopsis thaliana and the opportunistic pathogen Pseudomonas sp. N2C3, to identify mechanisms that determine the outcome of plant-pathogen-microbiome interactions in the rhizosphere. We screened 25 phylogenetically diverse Pseudomonas strains for their ability to protect against N2C3 and found that commensal strains closely related to N2C3, including Pseudomonas sp. WCS365, were more likely to protect against pathogenesis. We used comparative genomics to identify genes unique to the protective strains and found no genes that correlate with protection, suggesting that variable regulation of components of the core Pseudomonas genome may contribute to pathogen protection. We found that commensal colonization level was highly predictive of protection, so we tested deletions in genes required for rhizosphere colonization. We identified a response regulator , and two ColR-dependent genes with predicted roles in membrane modifications ( and ), that are required for Pseudomonas-mediated protection from N2C3. We found that WCS365 also protects against the agricultural pathogen Pseudomonas fuscovaginae SE-1, the causal agent of bacterial sheath brown rot of rice, in a ColR-dependent manner. This work establishes a gnotobiotic model to uncover mechanisms by which members of the microbiome can protect hosts from pathogens and informs our understanding of the use of beneficial strains for microbiome engineering in dysbiotic soil systems. Microbiota can protect diverse hosts from pathogens, and microbiome dysbiosis can result in increased vulnerability to opportunistic pathogens. Here, we developed a rhizosphere commensal-pathogen model to identify bacterial strains and mechanisms that can protect plants from an opportunistic Pseudomonas pathogen. Our finding that protective strains are closely related to the pathogen suggests that the presence of specific microbial taxa may help protect plants from disease. We found that commensal colonization level was highly correlated with protection, suggesting that competition with pathogens may play a role in protection. As we found that commensal Pseudomonas were also able to protect against an agricultural pathogen, this system may be broadly relevant for identifying strains and mechanisms to control agriculturally important pathogens. This work also suggests that beneficial plant-associated microbes may be useful for engineering soils where microbial complexity is low, such as hydroponic, or disturbed agricultural soils.
Topics: Arabidopsis; Pseudomonas fluorescens; Pseudomonas; Soil; Plant Roots; Transcription Factors
PubMed: 35100865
DOI: 10.1128/mbio.02892-21 -
Food Microbiology Oct 2020Biofilm formation is a frequent source of contamination of food products, which results in significant economic losses through microbial spoilage and poses serious...
Biofilm formation is a frequent source of contamination of food products, which results in significant economic losses through microbial spoilage and poses serious health concerns. Little is known about the fate of Staphylococcus aureus in the dual-species biofilms with Pseudomonas fluorescens an important spoiler commonly found in aquatic products. This study evaluates the interactions between mono- or dual-species biofilms formed by P. fluorescens and S. aureus, as well as the sensitivity of the two tested strains to carvacrol. The biofilm cell population, expolysaccharide production, biofilm structures of P. fluorescens as mono- and dual-species with S. aureus at ratios of 1:1 and 1:0.01 were investigated with different concentrations of carvacrol (0, 0.4, 0.8 and 1.6 mM) in fish juice at 30 °C. The results show that the biofilm cell population of S. aureus in the dual-species was significantly lower (p < 0.05) than that in the mono-species, compared to no difference for P. fluorescens. In the co-culture the dominance of P. fluorescens inhibited the growing population of S. aureus in both planktonic and biofilm cells, however, two strains were stimulated to produce the large expolysaccharides and coaggregation, forming the complex spatial multibiofilm structures. The large increase in the dual-species biofilms was positively correlated with high quorum sensing autoinductor-2 (AI-2), and exogenous 4,5-dihydroxy-2,3-pentanedione (the AI-2 precursor, DPD), rather than C-HSL, greatly stimulated the dual-species biofilm formation. In addition, carvacrol significantly reduced the tested biofilms and expolysaccharide secretion without affecting cell viability in a concentration-dependent manner, especially for S. aureus. Furthermore, the two strains as the dual-species biofilms exhibited lower sensitivity to carvacrol than the mono-culture, regardless of the level of inoculum of S. aureus, which was consistent with the decrease of AI-2 activity. The present study highlights that the interactions between P. fluorescens and S. aureus in dual-species biofilms promoted the large production of expolysaccharides and complex biofilm structures modulated by AI-2 signal, which results in the community-level resistance to carvacrol.
Topics: Animals; Biofilms; Cymenes; Drug Resistance, Bacterial; Extracellular Polymeric Substance Matrix; Fishes; Homoserine; Lactones; Microbial Interactions; Pseudomonas fluorescens; Quorum Sensing; Seafood; Staphylococcus aureus
PubMed: 32539951
DOI: 10.1016/j.fm.2020.103506 -
Vaccines Sep 2020Plants harbor various beneficial bacteria that modulate their innate immunity, resulting in induced systemic resistance (ISR) against various pathogens. However, the...
Plants harbor various beneficial bacteria that modulate their innate immunity, resulting in induced systemic resistance (ISR) against various pathogens. However, the immune mechanisms underlying ISR triggered by Bacillus spp. and Pseudomonas spp. against pathogens with different lifestyles are not yet clearly elucidated. Here, we show that root drenching of Arabidopsis plants with PTA-CT2 and PTA-271 can induce ISR against the necrotrophic fungus and the hemibiotrophic bacterium DC3000. In the absence of pathogen infection, both beneficial bacteria do not induce any consistent change in systemic immune responses. However, ISR relies on priming faster and robust expression of marker genes for the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways upon pathogen challenge. These responses are also associated with increased levels of SA, JA, and abscisic acid (ABA) in the leaves of bacterized plants after infection. The functional study also points at priming of the JA/ET and NPR1-dependent defenses as prioritized immune pathways in ISR induced by both beneficial bacteria against . However, -triggered ISR against DC3000 is dependent on SA, JA/ET, and NPR1 pathways, whereas -induced ISR requires JA/ET and NPR1 signaling pathways. The use of ABA-insensitive mutants also pointed out the crucial role of ABA signaling, but not ABA concentration, along with JA/ET signaling in primed systemic immunity by beneficial bacteria against DC3000, but not against . These results clearly indicate that ISR is linked to priming plants for enhanced common and distinct immune pathways depending on the beneficial strain and the pathogen lifestyle.
PubMed: 32899695
DOI: 10.3390/vaccines8030503 -
Letters in Applied Microbiology Apr 2023This study aimed to examine the inhibition of chlorogenic acid-grafted chitosan (CS-g-CA) on Pseudomonas fluorescens (P. fluorescens) and its biofilm. The minimum...
This study aimed to examine the inhibition of chlorogenic acid-grafted chitosan (CS-g-CA) on Pseudomonas fluorescens (P. fluorescens) and its biofilm. The minimum inhibitory concentration (MIC) of CS-g-CA against P. fluorescens was 1.25 mg/mL. Alkaline phosphatase (AKPase) leakage assay and scanning electron microscopy (SEM) observation showed that CS-g-CA causes structural damage to cell walls and membranes, resulting in the loss of function. In addition, CS-g-CA was able to disrupt the antioxidant system of P. fluorescens, interfere with energy metabolism, and interact with genomic DNA, affecting the normal physiological function of bacteria. It was also found that CS-g-CA inhibited the flagellar motility of P. fluorescens, which may be responsible for the inhibition of its biofilm formation. CS-g-CA at 2MIC was able to remove 71.64% of the mature biofilm and reduce the production of extracellular polysaccharides (EPS) by 60.72%. This was further confirmed by confocal laser scanning microscopy (CLSM), which showed a significant reduction in the amount of biofilm. In summary, CS-g-CA has strong antibacterial and anti-biofilm activities against P. fluorescens, and it can be applied as a potential seafood bacteriostatic agent.
Topics: Chitosan; Pseudomonas fluorescens; Chlorogenic Acid; Biofilms; Anti-Bacterial Agents; Seafood
PubMed: 37081770
DOI: 10.1093/lambio/ovad050 -
Proceedings. Biological Sciences Jan 2020Disturbances can play a major role in biological invasions: by destroying biomass, they alter habitat and resource abundances. Previous field studies suggest that...
Disturbances can play a major role in biological invasions: by destroying biomass, they alter habitat and resource abundances. Previous field studies suggest that disturbance-mediated invader success is a consequence of resource influxes, but the importance of other potential covarying causes, notably the opening up of habitats, have yet to be directly tested. Using experimental populations of the bacterium , we determined the relative importance of disturbance-mediated habitat opening and resource influxes, plus any interaction between them, for invader success of two ecologically distinct morphotypes. Resource addition increased invasibility, while habitat opening had little impact and did not interact with resource addition. Both invaders behaved similarly, despite occupying different ecological niches in the microcosms. Treatment also affected the composition of the resident population, which further affected invader success. Our results provide experimental support for the observation that resource input is a key mechanism through which disturbance increases invasibility.
Topics: Biomass; Ecology; Ecosystem; Introduced Species; Pseudomonas fluorescens
PubMed: 31992171
DOI: 10.1098/rspb.2019.2415