47 research outputs found

    Complete Genome Sequence of the Multiresistant Taxonomic Outlier Pseudomonas aeruginosa PA7

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    Pseudomonas aeruginosa PA7 is a non-respiratory human isolate from Argentina that is multiresistant to antibiotics. We first sequenced gyrA, gyrB, parC, parE, ampC, ampR, and several housekeeping genes and found that PA7 is a taxonomic outlier. We report here the complete sequence of the 6,588,339 bp genome, which has only about 95% overall identity to other strains. PA7 has multiple novel genomic islands and a total of 51 occupied regions of genomic plasticity. These islands include antibiotic resistance genes, parts of transposons, prophages, and a pKLC102-related island. Several PA7 genes not present in PAO1 or PA14 are putative orthologues of other Pseudomonas spp. and Ralstonia spp. genes. PA7 appears to be closely related to the known taxonomic outlier DSM1128 (ATCC9027). PA7 lacks several virulence factors, notably the entire TTSS region corresponding to PA1690-PA1725 of PAO1. It has neither exoS nor exoU and lacks toxA, exoT, and exoY. PA7 is serotype O12 and pyoverdin type II. Preliminary proteomic studies indicate numerous differences with PAO1, some of which are probably a consequence of a frameshift mutation in the mvfR quorum sensing regulatory gene

    The TolC Protein of Legionella pneumophila Plays a Major Role in Multi-Drug Resistance and the Early Steps of Host Invasion

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    Pneumonia associated with Iegionnaires's disease is initiated in humans after inhalation of contaminated aerosols. In the environment, Legionella pneumophila is thought to survive and multiply as an intracellular parasite within free-living amoeba. In the genome of L. pneumophila Lens, we identified a unique gene, tolC, encoding a protein that is highly homologous to the outer membrane protein TolC of Escherichia coli. Deletion of tolC by allelic exchange in L. pneumophila caused increased sensitivity to various drugs. The complementation of the tolC mutation in trans restored drug resistance, indicating that TolC is involved in multi-drug efflux machinery. In addition, deletion of tolC caused a significant attenuation of virulence towards both amoebae and macrophages. Thus, the TolC protein appears to play a crucial role in virulence which could be mediated by its involvement in efflux pump mechanisms. These findings will be helpful in unraveling the pathogenic mechanisms of L. pneumophila as well as in developing new therapeutic agents affecting the efflux of toxic compounds

    Microsatellite diversity of the Nordic type of goats in relation to breed conservation: how relevant is pure ancestry?

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    In the last decades, several endangered breeds of livestock species have been re-established effectively. However, the successful revival of the Dutch and Danish Landrace goats involved crossing with exotic breeds and the ancestry of the current populations is therefore not clear. We have generated genotypes for 27 FAO-recommended microsatellites of these landraces and three phenotypically similar Nordic-type landraces and compared these breeds with central European, Mediterranean and south-west Asian goats. We found decreasing levels of genetic diversity with increasing distance from the south-west Asian domestication site with a south-east-to-north-west cline that is clearly steeper than the Mediterranean east-to-west cline. In terms of genetic diversity, the Dutch Landrace comes next to the isolated Icelandic breed, which has an extremely low diversity. The Norwegian coastal goat and the Finnish and Icelandic landraces are clearly related. It appears that by a combination of mixed origin and a population bottleneck, the Dutch and Danish Land-races are separated from the other breeds. However, the current Dutch and Danish populations with the multicoloured and long-horned appearance effectively substitute for the original breed, illustrating that for conservation of cultural heritage, the phenotype of a breed is more relevant than pure ancestry and the genetic diversity of the original breed. More in general, we propose that for conservation, the retention of genetic diversity of an original breed and of the visual phenotype by which the breed is recognized and defined needs to be considered separately

    The Lake CHAd Deep DRILLing project (CHADRILL) - targeting ~ 10 million years of environmental and climate change in Africa

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    At present, Lake Chad ( ~13°0 N, ~14° E) is a shallow freshwater lake located in the Sahel/Sahara region of central northern Africa. The lake is primarily fed by the Chari-Logone river system draining a ~600 000 km2 watershed in tropical Africa. Discharge is strongly controlled by the annual passage of the intertropical convergence zone (ITCZ) and monsoon circulation leading to a peak in rainfall during boreal summer. During recent decades, a large number of studies have been carried out in the Lake Chad Basin (LCB). They have mostly focused on a patchwork of exposed lake sediments and outcrops once inhabited by early hominids. A dataset generated from a 673m long geotechnical borehole drilled in 1973, along with outcrop and seismic reflection studies, reveal several hundred metres of Miocene-Pleistocene lacustrine deposits. CHADRILL aims to recover a sedimentary core spanning the Miocene-Pleistocene sediment succession of Lake Chad through deep drilling. This record will provide significant insights into the modulation of orbitally forced changes in northern African hydroclimate under different climate boundary conditions such as high CO2 and absence of Northern Hemisphere ice sheets. These investigations will also help unravel both the age and the origin of the lake and its current desert surrounding. The LCB is very rich in early hominid fossils (Australopithecus bahrelghazali; Sahelanthropus tchadensis) of Late Miocene age. Thus, retrieving a sediment core from this basin will provide the most continuous climatic and environmental record with which to compare hominid migrations across northern Africa and has major implications for understanding human evolution. Furthermore, due to its dramatic and episodically changing water levels and associated depositional modes, Lake Chad's sediments resemble maybe an analogue for lake systems that were once present on Mars. Consequently, the study of the subsurface biosphere contained in these sediments has the potential to shed light on microbial biodiversity present in this type of depositional environment. We propose to drill a total of ~1800m of poorly to semi-consolidated lacustrine, fluvial, and eolian sediments down to bedrock at a single on-shore site close to the shoreline of present-day Lake Chad. We propose to locate our drilling operations on-shore close to the site where the geotechnical Bol borehole (13°280 N, 14°440 E) was drilled in 1973. This is for two main reasons: (1) nowhere else in the Chad Basin do we have such detailed information about the lithologies to be drilled; and (2) the Bol site is close to the depocentre of the Chad Basin and therefore likely to provide the stratigraphically most continuous sequence

    Designing a Family Concept Model in Divorce Applicant Couples Based on Grounded Theory

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    The present study tries to identify the concept of family in the lived experiences of divorced applicants, using a qualitative method of Foundation data. The aim of this study was to gain an understanding of the life experience of divorce applicants and to discover and extract models from these experiences and to map the relevant paradigms, including the interrelationships between conditions (structure), action (process), and consequences. Data obtained through in-depth and semi-structured interviews with divorce applicants of the Karaj Family Court. The study reached theoretical saturation through the purposive sampling method with a sample size of 9 spouses (n = 18). The data were analyzed through the Strauss & Corbin method in three stages of open, axial and selective coding. The findings show that the causal conditions are the family ideological and structural tyans formation, the family evolution, the cultural problems, and economic problems. The basis conditions include family disorder, the lack of the state interactions, having the tool interaction and neglect to the religion outcome dimension. Intervention conditions are composed of the lack of life skill, the incorrect culture of the modern technology use and the lack of the separation of the family public and private scope. The consequences are of three main categories: the inevitability of divorce, the consequences of divorce, and the loss of family support. The results of the research showed that the phenomenon or category of the family concept in the living experience of divorce applicants is the unbalanced development of the family. As a result, unbalanced family development is largely eliminated by life skills training and social support

    Short-term outcomes of transcatheter closure of secundum atrial septal defect in children and adolescents: An experience of two centers in Upper Egypt

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    Background: The aim of this study was to evaluate the acute and short-term outcomes of transcatheter closure of secundum atrial septal defect (ASD) in children and adolescents in the first 4-year experience in two institutional centers in Upper Egypt. Methods: This was a retrospective cohort study including 135 children and adolescents who underwent ASD closure between April 2012 and May 2016. A review of the acute and short-term outcomes and adverse events was performed. Results: The patients had a median age of 5 years (interquartile range: 3–9 years), 71% of patients were ≤5 years, and median weight was 17 kg (interquartile range: 13–30 kg). Single defects were observed in 113 patients (84%). The remainder had multiple or multifenestrated defects that were closed by a single device. The mean defect size of single defects and the mean interatrial septum length were 15.24 ± 5.16 mm and 38.13 ± 6.3 mm, respectively. The ratio of device to TEE (Transoesophageal echocardiography) size of ASD was 1.19 ± 0.12. The devices were implanted successfully in 98.5% of patients. Six cases had concordant PS (Pulmonary stenosis), patent ductus arteriosus or perimembranous ventricular septal defect and were treated with balloon dilation, or closure. No residual flow was seen after device placement except in one patient with multiple fenestrations. There were five high-severity adverse events (3.7%) with no mortality. Device erosion was confirmed in one of two patients with massive haemopericardium; embolization of the device with retrieval in one patient; and heart block was detected in two cases. No cardiac perforation, device erosion, embolization, thrombus formation, or clinical evidence of bacterial endocarditis was observed during follow-up. Conclusions: Transcatheter closure of ASDs in children and adolescents was feasible and safe in the first 4 years experience in our centers, with good short-term outcome. Balloon sizing is not necessary for transcatheter closure of secundum ASD. Multiple defects can be safety closed by a single device

    A bacterial endosymbiont of the fungus Rhizopus microsporus drives phagocyte evasion and opportunistic virulence

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    This is the final version. Available on open access from Elsevier via the DOI in this recordData and code availability: Genomic sequencing data is available through the Sequence Read Archive (SRA) on NCBI and accession codes for sequences referenced in this work are: R. pickettii: SRA: SRR16523121 and R. microsporus: SRA: SRR16610381. This work did not lead to the generation of any new code.Opportunistic infections by environmental fungi are a growing clinical problem, driven by an increasing population of people with immunocompromising conditions. Spores of the Mucorales order are ubiquitous in the environment but can also cause acute invasive infections in humans through germination and evasion of the mammalian host immune system. How they achieve this and the evolutionary drivers underlying the acquisition of virulence mechanisms are poorly understood. Here, we show that a clinical isolate of Rhizopus microsporus contains a Ralstonia pickettii bacterial endosymbiont required for virulence in both zebrafish and mice and that this endosymbiosis enables the secretion of factors that potently suppress growth of the soil amoeba Dictyostelium discoideum, as well as their ability to engulf and kill other microbes. As amoebas are natural environmental predators of both bacteria and fungi, we propose that this tri-kingdom interaction contributes to establishing endosymbiosis and the acquisition of anti-phagocyte activity. Importantly, we show that this activity also protects fungal spores from phagocytosis and clearance by human macrophages, and endosymbiont removal renders the fungal spores avirulent in vivo. Together, these findings describe a new role for a bacterial endosymbiont in Rhizopus microsporus pathogenesis in animals and suggest a mechanism of virulence acquisition through environmental interactions with amoebas.Wellcome TrustBiotechnology and Biological Sciences Research Council (BBSRC)Darwin Trust of EdinburghNational Institutes of Allergy and ImmunologyMedical Research Council (MRC)Royal Societ
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