<i>Campylobacter jejuni</i> motility is required for infection of the flagellotropic bacteriophage F341

Previous studies have identified a specific modification of the capsular polysaccharide as receptor for phages that infect Campylobacter jejuni. Using acapsular kpsM mutants of C. jejuni strains NCTC11168 and NCTC12658, we found that bacteriophage F341 infects C. jejuni independently of the capsule. In contrast, phage F341 does not infect C. jejuni NCTC11168 mutants that either lack the flagellar filaments (ΔflaAB) or that have paralyzed, i.e., nonrotating, flagella (ΔmotA and ΔflgP). Complementing flgP confirmed that phage F341 requires rotating flagella for successful infection. Furthermore, adsorption assays demonstrated that phage F341 does not adsorb to these nonmotile C. jejuni NCTC11168 mutants. Taken together, we propose that phage F341 uses the flagellum as a receptor. Phage-host interactions were investigated using fluorescence confocal and transmission electron microscopy. These data demonstrate that F341 binds to the flagellum by perpendicular attachment with visible phage tail fibers interacting directly with the flagellum. Our data are consistent with the movement of the C. jejuni flagellum being required for F341 to travel along the filament to reach the basal body of the bacterium. The initial binding to the flagellum may cause a conformational change of the phage tail that enables DNA injection after binding to a secondary receptor

Call-up people: Telephone uses in a historical perspective

The article presents a cultural-historical study of telephone uses in Sloveniain the twentieth century. Telephone is considered a cultural product, a social institution, and a technical apparatus. The article discusses broad consequences of the development of telephone, social context of the expansion of this communication technology, and different roles telephone had in the development from the first wire-line prototypes to the massive use of mobile phone. By presenting life-stories and recollections of phone uses in Slovenia,the author seeks to analyse the "telephone culture". She discusses the importance of telephone for the every-day life of people after the telephones have "invaded" private houses and individuals\u27 intimate worlds and thus re-defined the relationship between private and public communication, which echoed in the transformation of every-day habits, patterns of social interaction and sociability, and reorganisation of the society at large.Članek je kulturnozgodovinska študija razvoja in rab fiksne in mobilne telefonije v Sloveniji skozi dvajseto stoletje, pri čemer avtorica telefon obravnava kot kulturni produkt, družbeno institucijo in tehnični aparat. Zgodovina telefonije je tesno povezana z zgodovino tehnoloških inovacij, ki jih članek predstavi, predvsem pa se ukvarja z zgodovino telefonije kot kulturnega sredstva komuniciranja. V tem pogledu avtorico zanimajo širše posledice, ki jih je imel razvoj telefona, proučuje družbeni kontekst razširjanja te komunikacijske tehnologije ter različne vloge, ki jih je imel telefon na poti razvoja od prvih prototipov do množične rabe in mobilnega telefona kot široko razsejanega potrošniškega produkta. Prek nabora življenjskih zgodb in spominov na rabe telefonije v slovenskem prostoru članekobravnava tudi "telefonsko kulturo". Ugotavlja, kakšne pomene je imela telefonija za vsakdanja življenja ljudi, ko so telefoni vdrli tako v javni prostor kot tudi v domove in s tem v zasebne ter intimne svetove ljudi. Avtorico zanima, kako je telefonija redefi nirala javno in zasebno komuniciranje, kako je transformirala vsakdanje navade ljudi, vzorce in načine družbene interakcije in sociabilnosti, medsebojne stike in dojemanje sveta, kako je med seboj povezala oddaljene kraje in kako je reorganizirala družbo in številne družbene sfere

Motility of <i>C. jejuni</i> strains NCTC12658, NCTC12662 and RM1221 after 24 hours in low percentage agar.

<p>Motility was assessed as diameters, in centimetres, of growth zones after 24 and 48 h of incubation, only 24 h data is shown.</p

Electron micrographs of <i>C. jejuni</i> bacteriophages F362 (a and b) and F386 (c and d).

<p>a. Normal phage particle with extended tail and folded-up fibers. b. Phage particle with contracted tail sticking in small globular vesicles. Note the tail fibers are no longer visible. c. Normal phage particle with extended tail and flexible fibers with attached small terminal globular structures. d. Phage particle with contracted tail. Note tail fibers are still visible. Phages were stained with 2% uranyl acetate and examined on a Tecnai 10 transmission electron microscope. </p

Plaque assay of phage F380 on strain A. NCTC12662 and B. NCTC12662<i>∆kpsM</i>.

<p>Clearer lysis and plaque formation can be seen on the acapsular version of the <i>C. jejuni</i> strain. </p

Restriction patterns of digested phage genomes representing different profiles.

<p>A. HhaI profiles of group III (∼140 kb) phage genomes. Lane 1: Marker (New England Biolabs), lane 2: Phage F348 (Type IIIa), lane 3: Phage F360 (Type IIIb), lane 4: F362 (Type IIIc), lane 5: Phage F353 (Type IIId), lane 6: Phage F356 (Type IIIe), lane 7: Phage F371 (Type IIIf), lane 8: Phage F375 (Type IIIg), and lane 9: Marker (New England Biolabs). B. SmiI profiles of group II (∼190 kb) phage genomes. Lane 1: Marker (DNA marker λ Eco130I), lane 2: Phage F376 (Type IIa), lane 3: Phage F379 (Type IIb), lane 4: Phage F381 (Type IId), lane 5: Phage F388 (Type IIe). C. SmiI profile of phage F380 (Type IIc): Lane 1: Marker (DNA marker λ Eco130I), lane 2: phage F380.</p

Distribution of sampled farms indicated by number in circles located throughout Denmark.

<p>Black circles represent farms where phages could be isolated.</p