Search results for "mna"
showing 10 items of 1167 documents
Higher resource level promotes virulence in an environmentally transmitted bacterial fish pathogen
2017
Diseases have become a primary constraint to sustainable aquaculture, but remarkably little attention has been paid to a broad class of pathogens: the opportunists. Opportunists often persist in the environment outside the host, and their pathogenic features are influenced by changes in the environment. To test how environmental nutrient levels influence virulence, we used strains of Flavobacterium columnare, an environmentally transmitted fish pathogen, to infect rainbow trout and zebra fish in two different nutrient concentrations. To separate the effects of dose and nutrients, we used three infective doses and studied the growth of bacteria in vitro. High nutrient concentration promoted …
Cooperation between CRISPR-Cas types enables adaptation in an RNA-targeting system
2020
AbstractCRISPR-Cas immune systems adapt to new threats by acquiring spacers from invading nucleic acids such as phage genomes. However, some CRISPR-Cas loci lack genes necessary for spacer acquisition, despite apparent variation in spacer content between strains. It has been suggested that such loci may use acquisition machinery from co-occurring CRISPR-Cas systems. Here, using a lytic dsDNA phage, we observe spacer acquisition in the native host Flavobacterium columnare that carries an acquisition-deficient subtype VI-B locus and a complete subtype II-C locus. We characterize acquisition events in both loci and show that the RNA-targeting VI-B locus acquires spacers in trans using acquisit…
Mucin induces CRISPR-Cas defence in an opportunistic pathogen
2021
AbstractParasitism by bacteriophages has led to the evolution of a variety of defense mechanisms in their host bacteria. However, it is unclear what factors lead to specific defenses being deployed upon phage infection. To explore this question, we exposed the bacterial fish pathogenFlavobacterium columnareto its virulent phage V156 in the presence of a eukaryotic host signal (mucin). All tested conditions led to some level of innate immunity, but the presence of mucin led to a dramatic increase in CRISPR spacer acquisition, especially in low nutrient conditions where over 60% of colonies had obtained at least one new spacer. Additionally, we show that the presence of a competitor bacterium…
Furcocercous cercariae (Trematoda) from freshwater snails in Central Finland
2007
AbstractA total of eight species of furcocercous cercariae of four families (Strigeidae, Diplostomidae, Schistosomatidae and Sanguinicolidae), were found in 2005 in Lake Konnevesi in Central Finland in four snail species (Valvata macrostoma, Lymnaea stagnalis, Bathyomphalus contortus and Planorbarius corneus). Australapatemon burti (Miller, 1923), Australapatemon sp., Cotylurus brevis Dubois et Rausch, 1950, Cercaria spinulosa Ginetsinskaya, 1959 and Sanguinicola sp. are new species records for Finland. Ichthyocotylurus variegatus (Creplin, 1825) and Bilharziella polonica (Kowalewski, 1895) were first recorded as cercariae in Finland. The most common cercariae were A. burti (prevalence 13.3…
Bush, Sharon y los suyos
2004
Se trata de la versión mecanografiada del artículo publicado en "El País" el 16 de abril de 2004, pero debe aclararse que el texto es exactamente igual al publicado, únicamente cambia el título: "Los terminator de la democracia".
La implosión de Occidente
2005
Crecimiento económico, regresión social, crispación política
2004
Otra versión del artículo "Balance de la era Aznar" (En: Le monde diplomatique - Edición Cono Sur, nº 58, abril de 2004).
Le lourd héritage de l’ère Aznar
2004
La versión no publicada se titula "Un bilan convenu (sans surprise): croissance économique, crispation politique, régréssion sociale"
Balance de la era Aznar
2004
Versión española de "Le lourd héritage de l’ère Aznar" (En: Le monde diplomatique, abril de 2004).