Examinando por Autor "Urrutia, Homero"

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    Antagonistic activity of endophytic actinobacteria from native potatoes (Solanum tuberosum subsp. tuberosum L.) against Pectobacterium carotovorum subsp. carotovorum and Pectobacterium atrosepticum
    (BioMed Central Ltd, 2021-12) Padilla-Gálvez, Natalia; Luengo-Uribe, Paola; Mancilla, Sandra; Maurin, Amandine; Torres, Claudia; Ruiz, Pamela; France, Andrés; Acuña, Ivette; Urrutia, Homero
    Background: The native potatoes (Solanum tuberosum subsp. tuberosum L.) grown in Chile (Chiloé) represent a new, unexplored source of endophytes to fnd potential biological control agents for the prevention of bacterial diseases, like blackleg and soft rot, in potato crops. Result: The objective of this study was the selection of endophytic actinobacteria from native potatoes for antago‑ nistic activity against Pectobacterium carotovorum subsp. carotovorum and Pectobacterium atrosepticum, and their potential to suppress tissue maceration symptoms in potato tubers. This potential was determined through the quorum quenching activity using a Chromobacterium violaceaum ATCC 12472 Wild type (WT) bioassay and its colo‑ nization behavior of the potato plant root system (S. tuberosum) by means of the Double labeling of oligonucleotide probes for fuorescence in situ hybridization (DOPE-FISH) targeting technique. The results showed that although Strep tomyces sp. TP199 and Streptomyces sp. A2R31 were able to inhibit the growth of the pathogens, only the Streptomyces sp. TP199 isolate inhibited Pectobacterium sp. growth and diminished tissue maceration in tubers (p≤0.05). Streptomy ces sp. TP199 had metal-dependent acyl homoserine lactones (AHL) quorum quenching activity in vitro and was able to colonize the root endosphere 10 days after inoculation. Conclusions: We concluded that native potatoes from southern Chile possess endophyte actinobacteria that are potential agents for the disease management of soft rot and blackleg.
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    Effect of florfenicol on Piscirickettsia salmonis biofilm formed in materials used in salmonid nets, nylon and high-density polyethylene
    (John Wiley and Sons Inc, 2023) Oliver, Cristian; Ruiz, Pamela; Vidal, José Miguel; Carrasco, Carlos; Escalona, Carla Estefanía; Barros, Javier; Sepúlveda, Daniela; Urrutia, Homero; Romero, Alex
    Piscirickettsiosis is the most prevalent bacterial disease affecting seawater salmon in Chilean salmon industry. Antibiotic therapy is the first alternative to counteract infections caused by Piscirickettsia salmonis. The presence of bacterial biofilms on materials commonly used in salmon farming may be critical for understanding the bacterial persistence in the environment. In the present study, the CDC Biofilm Reactor® was used to investigate the effect of sub- and over-MIC of florfenicol on both the pre-formed biofilm and the biofilm formation by P. salmonis under the antibiotic stimuli on Nylon and high-density polyethylene (HDPE) surfaces. This study demonstrated that FLO, at sub- and over-MIC doses, decreases biofilm-embedded live bacteria in the P. salmonis isolates evaluated. However, it was shown that in the P. salmonis Ps007 strain the presence of sub-MIC of FLO reduced its biofilm formation on HDPE surfaces; however, biofilm persists on Nylon surfaces. These results demonstrated that P. salmonis isolates behave differently against FLO and also, depending on the surface materials. Therefore, it remains a challenge to find an effective strategy to control the biofilm formation of P. salmonis, and certainly other marine pathogens that affect the sustainability of the Chilean salmon industry. © 2023 John Wiley & Sons Ltd.
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    Piscirickettsia salmonis Produces a N-Acetyl-L-Homoserine Lactone as a Bacterial Quorum Sensing System-Related Molecule
    (Frontiers Media S.A., 2021-10-25) Ruiz, Pamela; Sepulveda, Daniela; Vidal, José Miguel; Romero, Romina; Contreras, David; Barros, Javier; Carrasco, Carlos; Ruiz-Tagle, Nathaly; Romero, Alex; Urrutia, Homero; Oliver, Cristian
    Piscirickettsia salmonis is the etiological agent of piscirickettsiosis, the most prevalent disease in salmonid species in Chilean salmonids farms. Many bacteria produce N-acyl-homoserine lactones (AHLs) as a quorum-sensing signal molecule to regulate gene expression in a cell density-dependent manner, and thus modulate physiological characteristics and several bacterial mechanisms. In this study, a fluorescent biosensor system method and gas chromatography-tandem mass spectrometry (GC/MS) were combined to detect AHLs produced by P. salmonis. These analyses revealed an emitted fluorescence signal when the biosensor P. putida EL106 (RPL4cep) was co-cultured with both, P. salmonis LF-89 type strain and an EM-90-like strain Ps007, respectively. Furthermore, the production of an AHL-type molecule was confirmed by GC/MS by both P. salmonis strains, which identified the presence of a N-acetyl-L-homoserine Lactone in the supernatant extract. However, It is suggested that an alternate pathway could synthesizes AHLs, which should be address in future experiments in order to elucidate this important bacterial process. To the best of our knowledge, the present report is the first to describe the type of AHLs produced by P. salmonis. Copyright © 2021 Ruiz, Sepulveda, Vidal, Romero, Contreras, Barros, Carrasco, Ruiz-Tagle, Romero, Urrutia and Oliver.