CRISPR Inhibition of Prophage Acquisition in Streptococcus pyogenes

Streptococcus pyogenes, one of the major human pathogens, is a unique species since it has acquired diverse strain-specific virulence properties mainly through the acquisition of streptococcal prophages. In addition, S. pyogenes possesses clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems that can restrict horizontal gene transfer (HGT) including phage insertion. Therefore, it was of interest to examine the relationship between CRISPR and acquisition of prophages in S. pyogenes. Although two distinct CRISPR loci were found in S. pyogenes, some strains lacked CRISPR and these strains possess significantly more prophages than CRISPR harboring strains. We also found that the number of spacers of S. pyogenes CRISPR was less than for other streptococci. The demonstrated spacer contents, however, suggested that the CRISPR appear to limit phage insertions. In addition, we found a significant inverse correlation between the number of spacers and prophages in S. pyogenes. It was therefore suggested that S. pyogenes CRISPR have permitted phage insertion by lacking its own spacers. Interestingly, in two closely related S. pyogenes strains (SSI-1 and MGAS315), CRISPR activity appeared to be impaired following the insertion of phage genomes into the repeat sequences. Detailed analysis of this prophage insertion site suggested that MGAS315 is the ancestral strain of SSI-1. As a result of analysis of 35 additional streptococcal genomes, it was suggested that the influences of the CRISPR on the phage insertion vary among species even within the same genus. Our results suggested that limitations in CRISPR content could explain the characteristic acquisition of prophages and might contribute to strain-specific pathogenesis in S. pyogenes

Get real: how to see through the hype, spin and lies of modern life

Book synopsis: Oil companies advertise their green credentials. Long-hours employees play table football at work. Billionaires organise ‘grassroots’ political movements. Cuts that target the poor are billed as progressive. To Eliane Glaser, these are all signs of the maddeningly surreal gap between appearance and reality in modern life. With the melting away of conflicts between East and West in the Cold War and Right and Left in our politics, the big ideologies were consigned to history. But ‘Get Real’ argues that agendas never really disappeared. They just went undercover, creating a looking-glass world in which reality is spun and vested interests appear in disguise. ‘Get Real’ is a passionate yet entertaining guide to spotting and decoding the delusions we live by – from plus-size models to home-grown veg; from natural childbirth to iphone apps. Only then can we improve our world for real

'A parallel made with the Jewish Sanhedrin': tolerating Jews and Jewish precedents in the early modern Church and state

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Book synopsis: Multinational oil corporations trumpet their green credentials. Shadowy billionaires orchestrate ‘grassroots’ political movements. Public-spending cuts that target the poor are billed as ‘giving power to the people’. Casually dressed employees play table football in airy open-plan offices, but work longer hours than ever before. These are just a few examples of the growing gap between appearance and reality in modern life. With the melting away of the conflicts between East and West and Right and Left, the old ideologies were supposedly consigned to history. But Eliane Glaser argues that they never really went away – they just went undercover, creating a looking-glass world in which reality is spun and crude vested interests appear in seductive new disguises. A world of illusion, persuasion and coercion which aims to conceal the truth and beguile us all. It’s time to radically alter the way we perceive the world, to raise a sceptical yet optimistic eyebrow. Time to get real. Get Real is a passionate and entertaining guide to spotting and decoding the delusions we live under – from ‘revolutionary’ plus-size models to ‘world-saving’ organic vegetables; from heavily scripted and edited ‘reality’ TV to ‘life-changing’ iPhone apps. Busting the jargon and unravelling the spin, Get Real reveals the secrets about modern life that we were never supposed to know. It’s an insider’s guide to understanding the present which puts the truth and the power to choose firmly in our hands. Only by telling it like it is can we improve – and maybe even save – our world for real

Reseña del libro

La autora elabora una reseña al libro escrito por Steven Levitsky y Daniel Ziblatt, profesores de la Universidad de Harvard, titulado: How Democracies Die: What History Reveals about Our Future.El libro fue publicado el 25 de enero de 201