DNA sequences of the repressor gene and operator region of bacteriophage P2

The nucleotide sequence of the repressor gene C of the temperate phage P2 has been determined. It codes for a nonbasic polypeptide, 99 amino acids long. Twelve repressor-defective mutants have been mapped. All but one are located within the presumed coding part of the gene. There is a strong promoter sequence and an 8-base-pair inverted repeat preceding the gene. The P2 repressor protein shows structural similarity to other DNA-binding proteins. The operator region for the early replication functions was located by sequencing the DNA of three virulent mutants. The sequence indicates that there are two repressor-binding sites. In addition, one of the sites shows sequence homology with part of the operator region of the biotin operon of Escherichia coli

The P2 phage old gene: sequence, transcription and translational control

The old (overcoming lysogenization defect) gene product of bacteriophage P2 kills Escherichia coli recB and recC mutants and interferes with phage [lambda] growth [ Sironi et al., Virology 46 (1971) 387-396 ; Lindahl et al., Proc. Natl. Acad. Sci. USA 66 (1970) 587-594]. Specialized transducing [lambda] phages, which lack the recombination region, can be selected by plating [lambda] stocks on E. coli that carry the old gene on a prophage or plasmid [Finkel et al., Gene 46 (1986) 65-69]. Deletion and sequence analyses indicate that the old-encoded protein has an Mr of 65 373 and that its transcription is leftward. Primer extension analyses locate the transcription start point near the right end of the virion DNA. A bacterial mutant, named pin3 and able to suppress the effects of the old gene, has been isolated [Ghisotti et al., J. Virol. 48 (1983) 616-626]. In a pin3 mutant strain, carrying the old gene on a prophage or plasmid, the amount of old transcript is greatly reduced. The effect of the pin3 mutation is abolished by the wild-type allele of argU, an arginine tRNA that reads the rare Arg codons AGA and AGG, which are used for eight of the 14 Arg codons in the old gene. Thus the pin3 allele probably stalls translation of the old mRNA, causing this mRNA to be degraded. Isoelectric focusing and electrophoretic analysis identify the old gene product as a basic protein of approx. 65 kDa.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27631/1/0000007.pd

Crystal structure of the P2 C-repressor: a binder of non-palindromic direct DNA repeats

As opposed to the vast majority of prokaryotic repressors, the immunity repressor of temperate Escherichia coli phage P2 (C) recognizes non-palindromic direct repeats of DNA rather than inverted repeats. We have determined the crystal structure of P2 C at 1.8 Å. This constitutes the first structure solved from the family of C proteins from P2-like bacteriophages. The structure reveals that the P2 C protein forms a symmetric dimer oriented to bind the major groove of two consecutive turns of the DNA. Surprisingly, P2 C has great similarities to binders of palindromic sequences. Nevertheless, the two identical DNA-binding helixes of the symmetric P2 C dimer have to bind different DNA sequences. Helix 3 is identified as the DNA-recognition motif in P2 C by alanine scanning and the importance for the individual residues in DNA recognition is defined. A truncation mutant shows that the disordered C-terminus is dispensable for repressor function. The short distance between the DNA-binding helices together with a possible interaction between two P2 C dimers are proposed to be responsible for extensive bending of the DNA. The structure provides insight into the mechanisms behind the mutants of P2 C causing dimer disruption, temperature sensitivity and insensitivity to the P4 antirepressor

Nationwide, population-based observational study of the molecular epidemiology and temporal trend of carbapenemase-producing Enterobacterales in Norway, 2015 to 2021

National and regional carbapenemaseproducing Enterobacterales (CPE) surveillance is essential to understand the burden of antimicrobial resistance, elucidate outbreaks, and develop infection-control or antimicrobial-treatment recommendations. Aim: This study aimed to describe CPE and their epidemiology in Norway from 2015 to 2021. Methods: A nationwide, population-based observational study of all verified clinical and carriage CPE isolates submitted to the national reference laboratory was conducted. Isolates were characterised by antimicrobial susceptibility testing, whole genome sequencing (WGS) and basic metadata. Annual CPE incidences were also estimated. Results: A total of 389 CPE isolates were identified from 332 patients of 63years median age (range:0–98). These corresponded to 341 cases, 184 (54%) being male. Between 2015 and 2021, the annual incidence of CPE cases increased from 0.6 to 1.1per 100,000person-years. For CPEisolates with available data on colonisation/infection, 58% (226/389)were associated with colonisation and 38% (149/389) with clinical infections. WGS revealed a predominance of OXA-48-like (51%; 198/389) and NDM (34%; 134/389) carbapenemases in a diversified population of Escherichia coli and Klebsiella pneumoniae, including high-risk clones also detected globally. Most CPE isolates were travel-related (63%;245/389). Although local outbreaks and healthcare-associated transmission occurred, no interregional spread was detected. Nevertheless, 18% (70/389) of isolates not directly related to import points towards potentially unidentified transmission routes. A decline in travelassociated cases was observed during the COVID-19 pandemic. Conclusions: The close-to-doubling of CPE case incidence between 2015 and 2021 was associated with foreign travel and genomic diversity. To limit further transmission and outbreaks, continued screening and monitoring is essential

Time to kill : a psychological study of world of warcraft as a cultural phenomenon

In the last five years, online games have grown in popularity. Thus a growing trend of so called massively multiplayer online role- playing games (MMORPG’s) has developed. With over 11 million players worldwide, World of Warcraft is the largest MMORPG today. The media and past research have a heavy focus on the addictive qualities of this game and other MMORPG’s, at the same time there is limited research done on the player’s social relationships outside the game and players’ and non- players’ stereotypes and attitudes. This study looks at what happens with the WoW players’ social relationships, the motives for playing, and how players are affected by stereotypes and attitudes. The method we have used is a mixed methods design. We conducted an online survey (n=228) through two large forums in Norway and some of these participants volunteered to also participate in an interview where we talked to the players and a friend, partner or family member of their choice. We conducted a total of 26 interviews with 13 pairs. The survey data was analysed and then used as a background for the qualitative part of this research, and the interviews were analyzed using a thematic approach. Identifying several themes, most interesting is the time aspect, motivations for playing, attitudes and stereotypes and social relationships. The results suggest that players with friends outside the game tended to talk about the game as a hobby, rather than as something that was their life, a more common response by those with few social relations outside the game. This indicates that strong relationships to people outside the game are a key factor when it comes to playing for fun and it being a hobby. This is an important notion in the further discussion of the stereotypic player. Negative attitudes and media publicity also affects the player to some extent. Further the results suggest that most of the players play because they are bored and have too much time on their hands. This is quite interesting in a time where most people see themselves as having too little time

Identification of bases required for P2 integrase core binding and recombination

AbstractTemperate coliphage P2 integrates its genome into the host chromosome upon lysogenization via a site-specific recombination event mediated by an integrase belonging to the complex family of tyrosine recombinases. The host integration site attB (BOB′) is localized in the end of the cyaR gene and shares 27 nucleotides with the core of attP (COC′). In the present study we determine the minimal attB site using an in vivo recombination assay. Ten nt on the left side (B) are found to be nonessential for recombination. We show that the integrase has higher affinity for the right side (B′) compared to B and that artificial B′OB′ and an attP site with a matching core (C′OC′) are efficient substrates for recombination in vitro. We have analyzed single nucleotides in attB and find that sequence homology within a non-centrally located quadruplet in the hypothetical overlap region is essential for efficient recombination in vivo