193 research outputs found
Data report: logging while drilling data analysis of Leg 171A, a multivariate statistical approach
In the northern Barbados accretionary wedge, several Deep Sea Drilling
Project (DSDP) and Ocean Drilling Program (ODP) legs (DSDP Leg
78 and ODP Legs 110, 156, and 171A) targeted the décollement and the
seaward extension of the décollement, the proto-décollement. During
Leg 171A, the logging while drilling (LWD) technique was used to determine
the physical properties variations along a profile across the deformation
front. Because of the unstable borehole conditions in
accretionary wedges, LWD is the most effective method for the measurements
of physical properties in these poorly consolidated sediments.
LWD data are acquired just above the drill bit a few minutes
after the formation has been drilled, yielding measurements as close to
in situ conditions as possible.
The large amount of LWD data and the demand for a quick, objective,
and reliable evaluation calls for the application of multivariate statistical
methods. The multivariate factor analysis is a method of
reducing the amount of logging data while giving them a new integrated
meaning with no loss of important information, resulting in factor
logs that are helpful tools for further interpretation. The cluster
analysis of the two or three most significant factors proved to be a useful
and objective method to identify and confirm significant logging
units. The main objective of the application of multivariate statistical
methods in this study is twofold. First, Leg 171A was a stand-alone logging
leg, where no cores were retrieved. The factor analysis was used as
an objective tool for a classification of the drilled sequences based on
their physical and chemical properties. The new factor logs mirror the
basic processes behind the measured geophysical properties and make
them easier to interpret. Second, in the succeeding cluster analysis, similar
geophysical properties are grouped into one cluster, reflecting one
logging unit. These objectively defined logging units can be compared
to statistical electrofacies, which are helpful in differentiating lithologic
characterizations. In particular for LWD measurements, the multivariate
statistical methods of factor and cluster analysis are helpful tools for
a fast, reliable, and objective definition of logging units, which should
be considered for future legs
Environmental reporting through an ethical looking glass
This paper adopts the lens of environmental ethics to explore whether there is a disparity between the ethical approaches of a company in comparison to those expressed by stakeholders in relation to environmental issues, specifically those communicated through the corporate environmental report. Discourse analysis is adopted to explore the environmental section of the sustainability reports of the case study company as compared to the responses of a sample of the company's stakeholders, using the lens of three branches of environmental ethics: utilitarianism, deontology and virtue ethics. Results indicate that the ethical approaches expressed in the case study company's environmental reports were grounded in utilitarianism and deontology, in contrast to a virtue ethics approach expressed by external stakeholders. The disparity widened as the relationship between the company and the stakeholder became less direct. This disparity signals a failure to meet one of the primary purposes for preparing sustainability reports: to engage with stakeholders. As such this research contributes to the literature by identifying a disparity in the how this information is communicated compared with how it is perceived by stakeholders. This has important implications for the success of current stakeholder engagement practices
Disseminated cutaneous Herpes Simplex Virus-1 in a woman with rheumatoid arthritis receiving Infliximab: A case report
<p>Abstract</p> <p>Introduction</p> <p>We present the case of a 49-year-old woman with a seronegative rheumatoid arthritis who developed pustular psoriasis whilst on etanercept and subsequently developed disseminated herpes simplex on infliximab.</p> <p>Case presentation</p> <p>Our patient presented with an inflammatory arthritis which failed to respond to both methotrexate and leflunomide, and sulphasalazine treatment led to side effects. She was started on etanercept but after 8 months of treatment developed scaly pustular lesions on her palms and soles typical of pustular psoriasis. Following the discontinuation of etanercept, our patient required high doses of oral prednisolone to control her inflammatory arthritis. A second biologic agent, infliximab, was introduced in addition to low-dose methotrexate and 15 mg of oral prednisolone. However, after just 3 infusions of infliximab, she was admitted to hospital with a fever, widespread itchy vesicular rash and worsening inflammatory arthritis. Fluid from skin vesicles examined by polymerase chain reaction showed Herpes Simplex Virus type 1. Blood cultures were negative and her chest X-ray was normal. Her infliximab was discontinued and she was started on acyclovir, 800 mg five times daily for 2 weeks. She made a good recovery with improvement in her skin within 48 hours.</p> <p>She continued for 2 months on a prophylactic dose of 400 mg bd. Her rheumatoid arthritis became increasingly active and a decision was made to introduce adalimumab alongside acyclovir. Acyclovir prophylaxis has been continued but the dose tapered so that she is taking only 200 mg of acyclovir on alternate days. There has been no recurrence of Herpes Simplex Virus lesions despite increasing adalimumab to 40 mg weekly 3 months after starting treatment.</p> <p>Conclusion</p> <p>We believe this to be the first reported case of widespread cutaneous Herpes Simplex Virus type 1 infection following treatment with infliximab. We discuss the clinical manifestations of Herpes Simplex Virus infections with particular emphasis on the immunosuppressed patient and the use of prophylactic acyclovir. Pustular psoriasis is now a well recognised but uncommon side effect of antitumour necrosis factor therapy and can lead to cessation of therapy, as in our patient's case.</p
Globular-shaped variable lymphocyte receptors B antibody multimerized by a hydrophobic clustering in hagfish
In hagfish and lampreys, two representative jawless vertebrates, the humoral immunity is directly mediated by variable lymphocyte receptors B (VLRBs). Both monomeric VLRBs are structurally and functionally similar, but their C-terminal tails differ: lamprey VLRB has a Cys-rich tail that forms disulfide-linked pentamers of dimers, contributing to its multivalency, whereas hagfish VLRB has a superhydrophobic tail of unknown structure. Here, we reveal that VLRBs obtained from hagfish plasma have a globular-shaped multimerized form (approximately 0.6 to 1.7 MDa) that is generated by hydrophobic clustering instead of covalent linkage. Electron microscopy (EM) and single-particle analysis showed that the multimerized VLRBs form globular-shaped clusters with an average diameter of 28.7 ± 2.2 nm. The presence of VLRBs in the complex was confirmed by immune-EM analysis using an anti-VLRB antibody. Furthermore, the hydrophobic hagfish C-terminus (HC) was capable of triggering multimerization and directing the cellular surface localization via a glycophosphatidylinositol linkage. Our results strongly suggest that the hagfish VLRB forms a previously unknown globular-shaped antibody. This novel identification of a structurally unusual VLRB complex may suggest that the adaptive immune system of hagfish differs from that of lamprey
Identification of vertebra-like elements and their possible differentiation from sclerotomes in the hagfish
The hagfish, a group of extant jawless fish, are known to lack true vertebrae and, for this reason, have often been excluded from the group Vertebrata. However, it has yet to be conclusively shown whether hagfish lack all vertebra-like structures, and whether their somites follow developmental processes and patterning distinct from those in lampreys and gnathostomes. Here we report the presence of vertebra-like cartilages in the in-shore hagfish, Eptatretus burgeri. These elements arise as small nodules occupying anatomical positions comparable to those of gnathostome vertebrae. Examination of hagfish embryos suggests that the ventromedial portion of a somite transforms into mesenchymal cells that express cognates of Pax1/9 and Twist, strikingly similar to the pattern of sclerotome development in gnathostomes. We conclude that the vertebra-like elements in the hagfish are homologous to gnathostome vertebrae, implying that this animal underwent secondary reduction of vertebrae in most of the trunk
Evolution of a Core Gene Network for Skeletogenesis in Chordates
The skeleton is one of the most important features for the reconstruction of vertebrate phylogeny but few data are available to understand its molecular origin. In mammals the Runt genes are central regulators of skeletogenesis. Runx2 was shown to be essential for osteoblast differentiation, tooth development, and bone formation. Both Runx2 and Runx3 are essential for chondrocyte maturation. Furthermore, Runx2 directly regulates Indian hedgehog expression, a master coordinator of skeletal development. To clarify the correlation of Runt gene evolution and the emergence of cartilage and bone in vertebrates, we cloned the Runt genes from hagfish as representative of jawless fish (MgRunxA, MgRunxB) and from dogfish as representative of jawed cartilaginous fish (ScRunx1–3). According to our phylogenetic reconstruction the stem species of chordates harboured a single Runt gene and thereafter Runt locus duplications occurred during early vertebrate evolution. All newly isolated Runt genes were expressed in cartilage according to quantitative PCR. In situ hybridisation confirmed high MgRunxA expression in hard cartilage of hagfish. In dogfish ScRunx2 and ScRunx3 were expressed in embryonal cartilage whereas all three Runt genes were detected in teeth and placoid scales. In cephalochordates (lancelets) Runt, Hedgehog and SoxE were strongly expressed in the gill bars and expression of Runt and Hedgehog was found in endo- as well as ectodermal cells. Furthermore we demonstrate that the lancelet Runt protein binds to Runt binding sites in the lancelet Hedgehog promoter and regulates its activity. Together, these results suggest that Runt and Hedgehog were part of a core gene network for cartilage formation, which was already active in the gill bars of the common ancestor of cephalochordates and vertebrates and diversified after Runt duplications had occurred during vertebrate evolution. The similarities in expression patterns of Runt genes support the view that teeth and placoid scales evolved from a homologous developmental module
Mechanism of the Very Efficient Quenching of Tryptophan Fluorescence in Human γD- and γS-Crystallins: The γ-Crystallin Fold May Have Evolved To Protect Tryptophan Residues from Ultraviolet Photodamage†
Proteins exposed to UV radiation are subject to irreversible photodamage through covalent modification of tryptophans (Trps) and other UV-absorbing amino acids. Crystallins, the major protein components of the vertebrate eye lens that maintain lens transparency, are exposed to ambient UV radiation throughout life. The duplicated β-sheet Greek key domains of β- and γ-crystallins in humans and all other vertebrates each have two conserved buried Trps. Experiments and computation showed that the fluorescence of these Trps in human γD-crystallin is very efficiently quenched in the native state by electrostatically enabled electron transfer to a backbone amide [Chen et al. (2006) Biochemistry 45, 11552−11563]. This dispersal of the excited state energy would be expected to minimize protein damage from covalent scission of the excited Trp ring. We report here both experiments and computation showing that the same fast electron transfer mechanism is operating in a different crystallin, human γS-crystallin. Examination of solved structures of other crystallins reveals that the Trp conformation, as well as favorably oriented bound waters, and the proximity of the backbone carbonyl oxygen of the n − 3 residues before the quenched Trps (residue n), are conserved in most crystallins. These results indicate that fast charge transfer quenching is an evolved property of this protein fold, probably protecting it from UV-induced photodamage. This UV resistance may have contributed to the selection of the Greek key fold as the major lens protein in all vertebrates.National Eye Institute (Grant EY 015834
An Amphioxus Gli Gene Reveals Conservation of Midline Patterning and the Evolution of Hedgehog Signalling Diversity in Chordates
Background. Hedgehog signalling, interpreted in receiving cells by Gli transcription factors, plays a central role in the development of vertebrate and Drosphila embryos. Many aspects of the signalling pathway are conserved between these lineages, however vertebrates have diverged in at least one key aspect: they have evolved multiple Gli genes encoding functionally-distinct proteins, increasing the complexity of the hedgehog-dependent transcriptional response. Amphioxus is one of the closest living relatives of the vertebrates, having split from the vertebrate lineage prior to the widespread gene duplication prominent in early vertebrate evolution. Principal findings. We show that amphioxus has a single Gli gene, which is deployed in tissues adjacent to sources of hedgehog signalling derived from the midline and anterior endoderm. This shows the duplication and divergence of the Gli family, and hence the origin of vertebrate Gli functional diversity, was specific to the vertebrate lineage. However we also show that the single amphioxus Gli gene produces two distinct transcripts encoding different proteins. We utilise three tests of Gli function to examine the transcription regulatory capacities of these different proteins, demonstrating one has activating activity similar to Gli2, while the other acts as a weak repressor, similar to Gli3. Conclusions. These data show that the vertebrates and amphioxus have evolved functionally-similar repertoires of Gli proteins using parallel molecular routes; vertebrates via gene duplication and divergence, and amphioxus via alternate splicing of a single gene. Our results demonstrate that similar functional complexity of intercellular signalling can be achieved via different evolutionary pathways
Framework for a Protein Ontology
Biomedical ontologies are emerging as critical tools in genomic and proteomic research, where complex data in disparate resources need to be integrated. A number of ontologies describe properties that can be attributed to proteins. For example, protein functions are described by the Gene Ontology (GO) and human diseases by SNOMED CT or ICD10. There is, however, a gap in the current set of ontologies – one that describes the protein entities themselves and their relationships. We have designed the PRotein Ontology (PRO) to facilitate protein annotation and to guide new experiments. The components of PRO extend from the classification of proteins on the basis of evolutionary relationships to the representation of the multiple protein forms of a gene (products generated by genetic variation, alternative splicing, proteolytic cleavage, and other post-translational modifications). PRO will allow the specification of relationships between PRO, GO and other ontologies in the OBO Foundry. Here we describe the initial development of PRO, illustrated using human and mouse proteins involved in the transforming growth factor-beta and bone morphogenetic protein signaling pathways
A Novel Cre Recombinase Imaging System for Tracking Lymphotropic Virus Infection In Vivo
BACKGROUND:Detection, isolation, and identification of individual virus infected cells during long term infection are critical to advance our understanding of mechanisms of pathogenesis for latent/persistent viruses. However, current approaches to study these viruses in vivo have been hampered by low sensitivity and effects of cell-type on expression of viral encoded reporter genes. We have designed a novel Cre recombinase (Cre)-based murine system to overcome these problems, and thereby enable tracking and isolation of individual in vivo infected cells. METHODOLOGY/PRINCIPAL FINDINGS:Murine gammaherpesvirus 68 (MHV-68) was used as a prototypic persistent model virus. A Cre expressing recombinant virus was constructed and characterised. The virus is attenuated both in lytic virus replication, producing ten-fold lower lung virus titres than wild type virus, and in the establishment of latency. However, despite this limitation, when the sEGFP7 mouse line containing a Cre-activated enhanced green fluorescent protein (EGFP) was infected with the Cre expressing virus, sites of latent and persistent virus infection could be identified within B cells and macrophages of the lymphoid system on the basis of EGFP expression. Importantly, the use of the sEGFP7 mouse line which expresses high levels of EGFP allowed individual virus positive cells to be purified by FACSorting. Virus gene expression could be detected in these cells. Low numbers of EGFP positive cells could also be detected in the bone marrow. CONCLUSIONS/SIGNIFICANCE:The use of this novel Cre-based virus/mouse system allowed identification of individual latently infected cells in vivo and may be useful for the study and long-term monitoring of other latent/persistent virus infections
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