94 research outputs found

    Double-scattering of 51 MeV deuterons on carbon

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    Diasporic Dreams, Middle Class Moralities and Migrant Domestic Workers among Muslim Filipinos in Saudi Arabia

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    This paper is about middle-class Muslim Filipinos in Saudi Arabia and their discourses about and relationships with migrant domestic workers. Saudi Arabia is not simply a temporary stopping point to a better future elsewhere, but is also a place where the middle-class aspirations of Muslim Filipinos may be realised and where their religious affiliations as Muslims may be seen as enhancing rather than detracting from those dreams and imaginings. As part of a large and diverse diasporic community, middle-class Filipinos routinely interact and socialise with working-class Filipinos. They often provide succour and support for their compatriots who labour under difficult and legally unprotected conditions. Some employ migrant domestic workers in their homes, many of whom are irregular or takas (escapees). At the same time, they reproduce and reinforce many of the gendered stereotypes of domestic workers that often suggest moral failings of one sort or another. The simultaneous embracing of and distancing from domestic workers reflects the anxieties of those, particularly women, whose tenuous hold of middle-class status is accomplished through, but also put at risk by, the precariousness of their sojourns abroad in the Kingdom

    Characterisation and genome sequence of the lytic Acinetobacter baumannii bacteriophage vB-AbaS-Loki

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    © 2017 Turner et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Acinetobacter baumannii has emerged as an important nosocomial pathogen in healthcare and community settings. While over 100 of Acinetobacter phages have been described in the literature, relatively few have been sequenced. This work describes the characterisation and genome annotation of a new lytic Acinetobacter siphovirus, vB-AbaS-Loki, isolated from activated sewage sludge. Sequencing revealed that Loki encapsulates a 41,308 bp genome, encoding 51 predicted open reading frames. Loki is most closely related to Acinetobacter phage IME-AB3 and more distantly related to Burkholderia phage KL1, Paracoccus phage vB-PmaS-IMEP1 and Pseudomonas phages vB-Pae-Kakheti25, vB-PaeS-SCH-Ab26 and PA73. Loki is characterised by a narrow host range, among the 40 Acinetobacter isolates tested, productive infection was only observed for the propagating host, A. baumannii ATCC 17978. Plaque formation was found to be dependent upon the presence of Ca2+ ions and adsorption to host cells was abolished upon incubation with a mutant of ATCC 17978 encoding a premature stop codon in lpxA. The complete genome sequence of vB-AbaS-Loki was deposited in the European Nucleotide Archive (ENA) under the accession number LN890663. Copyright

    Transcriptome dynamics of a broad host-range cyanophage and its hosts

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    Cyanobacteria are highly abundant in the oceans and are constantly exposed to lytic viruses. The T4-like cyanomyoviruses are abundant in the marine environment and have broad host-ranges relative to other cyanophages. It is currently unknown whether broad host-range phages specifically tailor their infection program for each host, or employ the same program irrespective of the host infected. Also unknown is how different hosts respond to infection by the same phage. Here we used microarray and RNA-seq analyses to investigate the interaction between the Syn9 T4-like cyanophage and three phylogenetically, ecologically and genomically distinct marine Synechococcus strains: WH7803, WH8102 and WH8109. Strikingly, Syn9 led a nearly identical infection and transcriptional program in all three hosts. Different to previous assumptions for T4-like cyanophages, three temporally regulated gene expression classes were observed. Furthermore, a novel regulatory element controlled early-gene transcription, and host-like promoters drove middle gene transcription, different to the regulatory paradigm for T4. Similar results were found for the P-TIM40 phage during infection of Prochlorococcus NATL2A. Moreover, genomic and metagenomic analyses indicate that these regulatory elements are abundant and conserved among T4-like cyanophages. In contrast to the near-identical transcriptional program employed by Syn9, host responses to infection involved host-specific genes primarily located in hypervariable genomic islands, substantiating islands as a major axis of phage-cyanobacteria interactions. Our findings suggest that the ability of broad host-range phages to infect multiple hosts is more likely dependent on the effectiveness of host defense strategies than on differential tailoring of the infection process by the phage

    Collagen-Like Proteins in Pathogenic E. coli Strains

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    The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages

    Genome sequence of Ostreococcus tauri virus OtV-2 enlightens the role of picoeukaryote niche separation in the ocean

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    Ostreococcus tauri, a unicellular marine green alga, is the smallest known free-living eukaryote and is ubiquitous in the surface oceans. The ecological success of this organism has been attributed to distinct low- and high-light adapted ecotypes existing in different niches at a range of depths in the ocean. Viruses have already been characterised that infect the high-light adapted strains. Ostreococcus tauri virus isolate OtV-2 is a large double stranded DNA algal virus that infects a low-light adapted strain of O. tauri and was assigned to the algal virus family Phycodnaviridae, genus Prasinovirus. Our working hypothesis for this study was that different viruses infecting high-light vs. low-light adapted O. tauri strains would provide clues to propagation strategies that would give them selective advantages within their particular light niche. Sequence analysis of the 184,409 base pair linear OtV-2 genome revealed a range of core functional genes exclusive to this low-light genotype and included a variety of unexpected genes, such as those encoding a RNA polymerase sigma factor, at least four DNA methyltransferases, a cytochrome b5 and a high affinity phosphate transporter. It is clear that OtV-2 has acquired a range of potentially functional genes from its host, other eukaryotes and even bacteria over evolutionary time. Such piecemeal accretion of genes is a trademark of large doublestranded DNA viruses that has allowed them to adapt their propagation strategies to keep up with host niche separation in the sunlit layers of the oceanic environment
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