Facultad de Ciencias de la Vida

URI permanente para esta comunidad

http://repositorio.unab.cl//handle/ria/2068

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En 2018 se fusionan la Facultad de Ciencias Biológicas, con la Facultad de Ecología y Recursos Naturales y se crea la Facultad de Ciencias de la Vida (Fac.CV)

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Examinando Facultad de Ciencias de la Vida por Materia "6S RNA"

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  • Miniatura
    Ítem
    Motility modulation by the small non-coding RNA SroC in Salmonella Typhimurium
    (Oxford University Press, 2015-08) Fuentes, Danitza N.; Calderón, Paulina F.; Acuña, Lillian G.; Rodas, Paula I.; Paredes-Sabja, Daniel; Fuentes, Juan A.; Gil, Fernando; Calderón, Iván L.
    Bacterial regulatory networks of gene expression include the interaction of diverse types of molecules such as the small non-coding RNAs (sRNAs) and their cognate messenger RNAs (mRNAs). In this study, we demonstrated that the Salmonella Typhimurium sRNA SroC is significantly expressed between the late-exponential and stationary phase of growth in an rpoS-dependent manner. The expression of flagellar genes predicted as targets of this sRNA was quantitatively analyzed in both a ΔsroC mutant and a SroC-overexpressing (pSroC) strain. Deletion of sroC increased flagellar gene expression (i.e. flhBAE and fliE). Conversely, overexpression of SroC reduced flhBAE and fliE expression. These observations correlated with phenotypic evaluation of motility, where sroC deletion slightly increased motility, which in turn, was drastically reduced upon overexpression of SroC. The effects of deletion and overexpression of sroC in biofilm formation were also examined, where the ΔsroC and pSroC strains exhibited a reduced and increased ability to form biofilm, respectively. Furthermore, electron microscopy revealed that the wild-type strain overexpressing SroC had a non-flagellated phenotype. Taken together, our results showed that S. Typhimurium sRNA SroC modulates the flagellar synthesis by down-regulating the expression of flhBAE and fliE genes. © FEMS 2015. All rights reserved.
  • Miniatura
    Ítem
    The small rna ryhb homologs from salmonella typhimurium restrain the intracellular growth and modulate the spi-1 gene expression within raw264.7 macrophages
    (MDPI AG, 2021-03) Peñaloza, D.; Acuña, L.G.; Barros, M.J.; Núñez, P.; Montt, F.; Gil, F.; Fuentes, J.A.; Calderón, I.L.
    Growing evidence indicates that small noncoding RNAs (sRNAs) play important regulatory roles during bacterial infection. In Salmonella Typhimurium, several sRNAs are strongly up-regulated within macrophages, but little is known about their role during the infection process. Among these sRNAs, the well-characterized paralogs RyhB-1 and RyhB-2 are two regulators of gene expression mainly related with the response to iron availability. To investigate the role of the sRNAs RyhB-1 and RyhB-2 from S. Typhimurium in the infection of RAW264.7 macrophages, we analyzed several phenotypic traits from intracellular mutant strains lacking one and both sRNAs. Deletion of RyhB-1 and/or RyhB-2 resulted in increased intracellular survival and faster replication within macrophages. The bacterial metabolic status inside macrophages was also analyzed, reveal-ing that all the mutant strains exhibited higher intracellular levels of ATP and lower NAD+/NADH ratios than the wild type. Expression analyses from bacteria infecting macrophages showed that RyhB-1 and RyhB-2 affect the intra-macrophage expression of bacterial genes associated with the Salmonella pathogenicity island 1 (SPI-1) and the type III secretion system (T3SS). With a two-plas-mid system and compensatory mutations, we confirmed that RyhB-1 and RyhB-2 directly interact with the mRNAs of the invasion chaperone SicA and the regulatory protein RtsB. Altogether, these results indicate that the RyhB homologs contribute to the S. Typhimurium virulence modulation inside macrophages by reducing the intracellular growth and down-regulating the SPI-1 gene ex-pression. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.