A family of Type VI secretion system effector proteins that form ion-selective pores

This work was supported by the Wellcome Trust (104556/Z/14/Z, Senior Fellowship in Basic Biomedical Science to S.J.C.; 097818/Z/11/B and 109118/Z/15/Z, PhD studentships to University of Dundee), the MRC (MR/K000111X/1, New Investigator Research Grant to S.J.C.) and the Royal Society of Edinburgh (Biomedical Personal Research Fellowship to S.J.P.). We thank Roland Freudl for the gift of anti-OmpA antibody; Adam Ostrowski for construction of strains AO07 and AO08; Gal Horesh, Amy Dorward and Gavin Robertson for expert assistance; the Flow Cytometry and Cell Sorting Facility at the University of Dundee; and the Dundee Imaging Facility (supported by Wellcome Trust [097945/B/11/Z] and MRC [MR/K015869/1]) awards).Type VI secretion systems (T6SSs) are nanomachines widely used by bacteria to deliver toxic effector proteins directly into neighbouring cells. However, the modes of action of many effectors remain unknown. Here we report that Ssp6, an anti-bacterial effector delivered by a T6SS of the opportunistic pathogen Serratia marcescens, is a toxin that forms ion-selective pores. Ssp6 inhibits bacterial growth by causing depolarisation of the inner membrane in intoxicated cells, together with increased outer membrane permeability. Reconstruction of Ssp6 activity in vitro demonstrates that it forms cation-selective pores. A survey of bacterial genomes reveals that genes encoding Ssp6-like effectors are widespread in Enterobacteriaceae and often linked with T6SS genes. We conclude that Ssp6 and similar proteins represent a new family of T6SS-delivered anti-bacterial effectors.Publisher PDFPeer reviewe

Wstępne badania antymikrobowej aktywności poliamidowego runa elektroprzędzionych nanowłókien zawierających mikrocząsteczki bałtyckiego bursztynu

Antimicrobial textile is a very important field for new investigations. The two aspects need be taken into account at the time of such investigations into the protection of the textile itself from damage caused by microorganisms, and that of the textile user against pathogenic or odour causing microorganisms. However, it is known that some materials which have really good antimicrobial activity are harmful or toxic and cannot be used for health care or medical application, due to which the necessity to find new natural and human friendly antimicrobial active materials and methods of how to increase the antimicrobial activity of textile is still open. One of the ways to solve this problem is usage of natural antimicrobial agents such as chitosan, plant extracts and others. Investigations on the usage of amber micro particles in the formation of a polyamide 6 nanoweb via electrospinning and on the antimicrobial activity thereof is analyzed in this paper. The results show the antimicrobial activity of the material with Baltic amber investigated and the possibility of developing functional antimicrobial textile with amber micro particles via electrospinning.Antymikrobowe tekstylia są bardzo ważnym przedmiotem nowych badań. Badając bierze się pod uwagę zarówno możliwości uszkodzenia samych tkanin przez mikroorganizmy, jak również działanie mikroorganizmów na użytkownika. Istotnym elementem, który należy brać pod uwagę jest to, że niektóre środki antymikrobowe są szkodliwe dla użytkownika dlatego poszukuje się nowych substancji antymikrobowych zwłaszcza pochodzenia naturalnego. W tym celu badano wpływ mikrocząstek bursztynu zawartych w runie z nanowłókien uzyskanych przez elektroprzędzenie. Wyniki okazały się obiecujące