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PacBio assembly of a Plasmodium knowlesi genome sequence with Hi-C correction and manual annotation of the SICAvar gene family.
Plasmodium knowlesi has risen in importance as a zoonotic parasite that has been causing regular episodes of malaria throughout South East Asia. The P. knowlesi genome sequence generated in 2008 highlighted and confirmed many similarities and differences in Plasmodium species, including a global view of several multigene families, such as the large SICAvar multigene family encoding the variant antigens known as the schizont-infected cell agglutination proteins. However, repetitive DNA sequences are the bane of any genome project, and this and other Plasmodium genome projects have not been immune to the gaps, rearrangements and other pitfalls created by these genomic features. Today, long-read PacBio and chromatin conformation technologies are overcoming such obstacles. Here, based on the use of these technologies, we present a highly refined de novo P. knowlesi genome sequence of the Pk1(A+) clone. This sequence and annotation, referred to as the 'MaHPIC Pk genome sequence', includes manual annotation of the SICAvar gene family with 136 full-length members categorized as type I or II. This sequence provides a framework that will permit a better understanding of the SICAvar repertoire, selective pressures acting on this gene family and mechanisms of antigenic variation in this species and other pathogens
A Linear Epitope in the N-Terminal Domain of CCR5 and Its Interaction with Antibody.
The CCR5 receptor plays a role in several key physiological and pathological processes and is an important therapeutic target. Inhibition of the CCR5 axis by passive or active immunisation offers one very selective strategy for intervention. In this study we define a new linear epitope within the extracellular domain of CCR5 recognised by two independently produced monoclonal antibodies. A short peptide encoding the linear epitope can induce antibodies which recognise the intact receptor when administered colinear with a tetanus toxoid helper T cell epitope. The monoclonal antibody RoAb 13 is shown to bind to both cells and peptide with moderate to high affinity (6x10^8 and 1.2x107 M-1 respectively), and binding to the peptide is enhanced by sulfation of tyrosines at positions 10 and 14. RoAb13, which has previously been shown to block HIV infection, also blocks migration of monocytes in response to CCR5 binding chemokines and to inflammatory macrophage conditioned medium. A Fab fragment of RoAb13 has been crystallised and a structure of the antibody is reported to 2.1 angstrom resolution
Identification of Therapeutic Targets of Inflammatory Monocyte Recruitment to Modulate the Allogeneic Injury to Donor Cornea
Purpose: We sought to test the hypothesis that monocytes contribute to the immunopathogenesis of corneal allograft rejection and identify therapeutic targets to inhibit monocyte recruitment.
Methods: Monocytes and proinflammatory mediators within anterior chamber samples during corneal graft rejection were quantified by flow cytometry and multiplex protein assays. Lipopolysaccharide or IFN-γ stimulation of monocyte-derived macrophages (MDMs) was used to generate inflammatory conditioned media (CoM). Corneal endothelial viability was tested by nuclear counting, connexin 43, and propidium iodide staining. Chemokine and chemokine receptor expression in monocytes and MDMs was assessed in microarray transcriptomic data. The role of chemokine pathways in monocyte migration across microvascular endothelium was tested in vitro by chemokine depletion or chemokine receptor inhibitors.
Results: Inflammatory monocytes were significantly enriched in anterior chamber samples within 1 week of the onset of symptoms of corneal graft rejection. The MDM inflammatory CoM was cytopathic to transformed human corneal endothelia. This effect was also evident in endothelium of excised human cornea and increased in the presence of monocytes. Gene expression microarrays identified monocyte chemokine receptors and cognate chemokines in MDM inflammatory responses, which were also enriched in anterior chamber samples. Depletion of selected chemokines in MDM inflammatory CoM had no effect on monocyte transmigration across an endothelial blood–eye barrier, but selective chemokine receptor inhibition reduced monocyte recruitment significantly.
Conclusions: We propose a role for inflammatory monocytes in endothelial cytotoxicity in corneal graft rejection. Therefore, targeting monocyte recruitment offers a putative novel strategy to reduce donor endothelial cell injury in survival of human corneal allografts
apex: phylogenetics with multiple genes.
Genetic sequences of multiple genes are becoming increasingly common for a wide range of organisms including viruses, bacteria and eukaryotes. While such data may sometimes be treated as a single locus, in practice, a number of biological and statistical phenomena can lead to phylogenetic incongruence. In such cases, different loci should, at least as a preliminary step, be examined and analysed separately. The r software has become a popular platform for phylogenetics, with several packages implementing distance-based, parsimony and likelihood-based phylogenetic reconstruction, and an even greater number of packages implementing phylogenetic comparative methods. Unfortunately, basic data structures and tools for analysing multiple genes have so far been lacking, thereby limiting potential for investigating phylogenetic incongruence. In this study, we introduce the new r package apex to fill this gap. apex implements new object classes, which extend existing standards for storing DNA and amino acid sequences, and provides a number of convenient tools for handling, visualizing and analysing these data. In this study, we introduce the main features of the package and illustrate its functionalities through the analysis of a simple data set
Summary of the First Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE1)
Challenges related to development, deployment, and maintenance of reusable software for science are becoming a growing concern. Many scientists’ research increasingly depends on the quality and availability of software upon which their works are built. To highlight some of these issues and share experiences, the First Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE1) was held in November 2013 in conjunction with the SC13 Conference. The workshop featured keynote presentations and a large number (54) of solicited extended abstracts that were grouped into three themes and presented via panels. A set of collaborative notes of the presentations and discussion was taken during the workshop.
Unique perspectives were captured about issues such as comprehensive documentation, development and deployment practices, software licenses and career paths for developers. Attribution systems that account for evidence of software contribution and impact were also discussed. These include mechanisms such as Digital Object Identifiers, publication of “software papers”, and the use of online systems, for example source code repositories like GitHub. This paper summarizes the issues and shared experiences that were discussed, including cross-cutting issues and use cases. It joins a nascent literature seeking to understand what drives software work in science, and how it is impacted by the reward systems of science. These incentives can determine the extent to which developers are motivated to build software for the long-term, for the use of others, and whether to work collaboratively or separately. It also explores community building, leadership, and dynamics in relation to successful scientific software
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