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1.
Sensors (Basel) ; 23(24)2023 Dec 18.
Article in English | MEDLINE | ID: mdl-38139747

ABSTRACT

In recent decades, there have been significant research efforts focusing on wireless indoor localization systems, with fingerprinting techniques based on received signal strength leading the way. The majority of the suggested approaches require challenging and laborious Wi-Fi site surveys to construct a radio map, which is then utilized to match radio signatures with particular locations. In this paper, a novel next-generation cyber-physical wireless indoor positioning system is presented that addresses the challenges of fingerprinting techniques associated with data collection. The proposed approach not only facilitates an interactive digital representation that fosters informed decision-making through a digital twin interface but also ensures adaptability to new scenarios, scalability, and suitability for large environments and evolving conditions during the process of constructing the radio map. Additionally, it reduces the labor cost and laborious data collection process while helping to increase the efficiency of fingerprint-based positioning methods through accurate ground-truth data collection. This is also convenient for working in remote environments to improve human safety in locations where human access is limited or hazardous and to address issues related to radio map obsolescence. The feasibility of the cyber-physical system design is successfully verified and evaluated with real-world experiments in which a ground robot is utilized to obtain a radio map autonomously in real-time in a challenging environment through an informed decision process. With the proposed setup, the results demonstrate the success of RSSI-based indoor positioning using deep learning models, including MLP, LSTM Model 1, and LSTM Model 2, achieving an average localization error of ≤2.16 m in individual areas. Specifically, LSTM Model 2 achieves an average localization error as low as 1.55 m and 1.97 m with 83.33% and 81.05% of the errors within 2 m for individual and combined areas, respectively. These outcomes demonstrate that the proposed cyber-physical wireless indoor positioning approach, which is based on the application of dynamic Wi-Fi RSS surveying through human feedback using autonomous mobile robots, effectively leverages the precision of deep learning models, resulting in localization performance comparable to the literature. Furthermore, they highlight its potential for suitability for deployment in real-world scenarios and practical applicability.

2.
Proc Natl Acad Sci U S A ; 115(40): E9288-E9297, 2018 10 02.
Article in English | MEDLINE | ID: mdl-30237286

ABSTRACT

The formation of uniaxial fibrous tissues with defined viscoelastic properties implies the existence of an orchestrated mechanical interaction between the cytoskeleton and the extracellular matrix. This study addresses the nature of this interaction. The hypothesis is that this mechanical interplay underpins the mechanical development of the tissue. In embryonic tendon tissue, an early event in the development of a mechanically robust tissue is the interaction of the pointed tips of extracellular collagen fibrils with the fibroblast plasma membrane to form stable interface structures (fibripositors). Here, we used a fibroblast-generated tissue that is structurally and mechanically matched to embryonic tendon to demonstrate homeostasis of cell-derived and external strain-derived tension over repeated cycles of strain and relaxation. A cell-derived oscillatory tension component is evident in this matrix construct. This oscillatory tension involves synchronization of individual cell forces across the construct and is induced in each strain cycle by transient relaxation and transient tensioning of the tissue. The cell-derived tension along with the oscillatory component is absent in the presence of blebbistatin, which disrupts actinomyosin force generation of the cell. The time period of this oscillation (60-90 s) is well-defined in each tissue sample and matches a primary viscoelastic relaxation time. We hypothesize that this mechanical oscillation of fibroblasts with plasma membrane anchored collagen fibrils is a key factor in mechanical sensing and feedback regulation in the formation of tensile tissues.


Subject(s)
Cell Membrane/metabolism , Extracellular Matrix/metabolism , Fibroblasts/metabolism , Stress, Mechanical , Tensile Strength , Humans
3.
Sensors (Basel) ; 20(21)2020 Oct 30.
Article in English | MEDLINE | ID: mdl-33143242

ABSTRACT

The inspection of aquatic environments is a challenging activity, which is made more difficult if the environment is complex or confined, such as those that are found in nuclear storage facilities and accident sites, marinas and boatyards, liquid storage tanks, or flooded tunnels and sewers. Human inspections of these environments are often dangerous or infeasible, so remote inspection using unmanned underwater vehicles (UUVs) is used. Due to access restrictions and environmental limitations, such as low illumination levels, turbidity, and a lack of salient features, traditional localisation systems that have been developed for use in large bodies of water cannot be used. This means that UUV capabilities are severely restricted to manually controlled low-quality visual inspections, generating non-geospatially located data. The localisation of UUVs in these environments would enable the autonomous behaviour and the development of accurate maps. This article presents a review of the state-of-the-art in localisation technologies for these environments and identifies areas of future research to overcome the challenges posed.

4.
PLoS Pathog ; 13(12): e1006749, 2017 Dec.
Article in English | MEDLINE | ID: mdl-29284042

ABSTRACT

The global-scale epidemiology and genome-wide evolutionary dynamics of influenza B remain poorly understood compared with influenza A viruses. We compiled a spatio-temporally comprehensive dataset of influenza B viruses, comprising over 2,500 genomes sampled worldwide between 1987 and 2015, including 382 newly-sequenced genomes that fill substantial gaps in previous molecular surveillance studies. Our contributed data increase the number of available influenza B virus genomes in Europe, Africa and Central Asia, improving the global context to study influenza B viruses. We reveal Yamagata-lineage diversity results from co-circulation of two antigenically-distinct groups that also segregate genetically across the entire genome, without evidence of intra-lineage reassortment. In contrast, Victoria-lineage diversity stems from geographic segregation of different genetic clades, with variability in the degree of geographic spread among clades. Differences between the lineages are reflected in their antigenic dynamics, as Yamagata-lineage viruses show alternating dominance between antigenic groups, while Victoria-lineage viruses show antigenic drift of a single lineage. Structural mapping of amino acid substitutions on trunk branches of influenza B gene phylogenies further supports these antigenic differences and highlights two potential mechanisms of adaptation for polymerase activity. Our study provides new insights into the epidemiological and molecular processes shaping influenza B virus evolution globally.


Subject(s)
Influenza B virus/genetics , Influenza, Human/epidemiology , Influenza, Human/virology , Amino Acid Substitution , Antigenic Variation , Antigens, Viral/genetics , Databases, Genetic , Evolution, Molecular , Genetic Variation , Genome, Viral , Global Health , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Humans , Influenza B virus/classification , Influenza B virus/immunology , Models, Molecular , Molecular Epidemiology , Phylogeny , RNA-Dependent RNA Polymerase/chemistry , RNA-Dependent RNA Polymerase/genetics , Reassortant Viruses/genetics , Viral Proteins/chemistry , Viral Proteins/genetics
5.
Ecol Appl ; 29(8): e01980, 2019 12.
Article in English | MEDLINE | ID: mdl-31330069

ABSTRACT

Conservation managers regularly burn vegetation to regenerate habitat for fire-dependent species. When determining the time since fire at which to burn, managers model change in a species' occurrence over time, post-fire (fire-response curve) and identify the time since fire associated with decline in occurrence. However, where species exhibit variability in their fire response across space, using a single fire-response curve to determine the timing of burns may lead to burning habitat at an inappropriate time since fire. We tested if elevation, local topography, soil properties, vegetation type or evapotranspiration affect the fire response of the endangered Mallee Emu-wren Stipiturus mallee and its hummock-grass habitat Triodia scariosa in southeastern Australia (n = 217). Previous work on the Mallee Emu-wren found a unimodal fire response with decline in occurrence at ~30-50 yr since fire and a time window of occurrence of ~30 yr. We found that time since fire and elevation interact to affect the Mallee Emu-wren fire response. At high elevations (55-98 m), Mallee Emu-wrens declined in occurrence at ~50 yr since fire, with a time window of occurrence of 20-40 yr. However, at low elevations (28-55 m), Mallee Emu-wrens showed no decline in occurrence with increasing time since fire with a time window of occurrence of up to 107 yr. Extent cover of Tall T. scariosa showed similar patterns to the Mallee Emu-wren, indicating that vegetation structure is a likely driver of variability in the Mallee Emu-wren fire response. We speculate that the effect of low elevation is mediated by increased soil nutrient and water availability for key plants. We used our findings to map the appropriate time since fire at which to burn to regenerate habitat for the Mallee Emu-wren across the study region. We recommend no burning for regeneration across one-third of potential habitat, because the Mallee Emu-wren showed no decline in occurrence in these areas. We recommend managers model variability in species' fire responses across space to improve the timing of burns for regeneration.


Subject(s)
Fires , Animals , Australia , Birds , Ecosystem , Soil
6.
Ecol Appl ; 29(8): e01997, 2019 12.
Article in English | MEDLINE | ID: mdl-31483902

ABSTRACT

In an era characterized by recurrent large wildfires in many parts of the globe, there is a critical need to understand how animal species respond to fires, the rates at which populations can recover, and the functional changes fires may cause. Using quantified changes in habitat parameters over a ~400-yr post-fire chronosequence in an obligate-seeding Australian eucalypt woodland, we build and test predictions of how birds, as individual species and aggregated into functional groups according to their use of specific habitat resources, respond to time since fire. Individual bird species exhibited four generalized response types to time since fire: incline, decline, delayed, and bell. All significant relationships between bird functional group richness or abundance and time since fire were consistent with predictions based on known time-since-fire-associated changes in habitat features putatively important for these bird groups. Consequently, we argue that the bird community is responding to post-fire successional changes in habitat as per the habitat accommodation model, rather than to time since fire per se, and that our functional framework will be of value in predicting bird responses to future disturbances in this and other obligate-seeder forest and woodland ecosystems. Most bird species and functional groups that were affected by time since fire were associated with long-unburned woodlands. In the context of recent large, stand-replacement wildfires that have affected a substantial proportion of obligate-seeder eucalypt woodlands, and the multi-century timescales over which post-fire succession occurs, it would appear preferable from a bird conservation perspective if fires initiating loss of currently long-unburned woodlands were minimized. Once long-unburned woodlands are transformed by fire into recently burned woodlands, there is limited scope for alternative management interventions to accelerate the rate of habitat development after fire, or supplement the resources formerly provided to birds by long-unburned woodlands, with the limited exception of augmenting hollow availability for key hollow-nesting species.


Subject(s)
Ecosystem , Fires , Animals , Australia , Birds , Conservation of Natural Resources , Forests , Population Dynamics
7.
Sensors (Basel) ; 19(20)2019 Oct 22.
Article in English | MEDLINE | ID: mdl-31652658

ABSTRACT

The use of robotics in harsh environments, such as nuclear decommissioning, has increased in recent years. Environments such as the Fukushima Daiichi accident site from 2011 and the Sellafield legacy ponds highlight the need for robotic systems capable of deployment in hazardous environments unsafe for human workers. To characterise these environments, it is important to develop robust and accurate localization systems that can be combined with mapping techniques to create 3D reconstructions of the unknown environment. This paper describes the development and experimental verification of a localization system for an underwater robot, which enabled the collection of sonar data to create 3D images of submerged simulated fuel debris. The system was demonstrated at the Naraha test facility, Fukushima prefecture, Japan. Using a camera with a bird's-eye view of the simulated primary containment vessel, the 3D position and attitude of the robot was obtained using coloured LED markers (active markers) on the robot, landmarks on the test-rig (passive markers), and a depth sensor on the robot. The successful reconstruction of a 3D image has been created through use of a robot operating system (ROS) node in real-time.

8.
J Infect Dis ; 218(11): 1700-1710, 2018 10 20.
Article in English | MEDLINE | ID: mdl-30010810

ABSTRACT

Background: Kaposi sarcoma-associated herpesvirus (KSHV) establishes lifelong infection in the human host and has been associated with a variety of malignancies. KSHV displays striking geographic variation in prevalence, which is highest in sub-Saharan Africa. The current KSHV genome sequences available are all tumor cell line-derived or primary tumor-associated viruses, which have provided valuable insights into KSHV genetic diversity. Methods: Here, we sequenced 45 KSHV genomes from a Ugandan population cohort in which KSHV is endemic; these are the only genome sequences obtained from nondiseased individuals and of KSHV DNA isolated from saliva. Results: Population structure analysis, along with the 25 published genome sequences from other parts of the world, showed whole-genome variation, separating sequences and variation within the central genome contributing to clustering of genomes by geography. We reveal new evidence for the presence of intragenic recombination and multiple recombination events contributing to the divergence of genomes into at least 5 distinct types. Discussion: This study shows that large-scale genome-wide sequencing from clinical and epidemiological samples is necessary to capture the full extent of genetic diversity of KSHV, including recombination, and provides evidence to suggest a revision of KSHV genotype nomenclature.


Subject(s)
Genomics/methods , Herpesvirus 8, Human/genetics , Recombination, Genetic/genetics , Sarcoma, Kaposi/virology , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , DNA, Viral/genetics , Female , Genome-Wide Association Study , Humans , Male , Middle Aged , Sequence Analysis, DNA , Uganda , Young Adult
9.
Mol Pharmacol ; 89(5): 593-605, 2016 May.
Article in English | MEDLINE | ID: mdl-26916831

ABSTRACT

Here we describe the pharmacologic properties of a series of clinically relevant chemoattractant receptor-homologous molecules expressed on T-helper type 2 (CRTh2) receptor antagonists, including fevipiprant (NVP-QAW039 or QAW039), which is currently in development for the treatment of allergic diseases. [(3)H]-QAW039 displayed high affinity for the human CRTh2 receptor (1.14 ± 0.44 nM) expressed in Chinese hamster ovary cells, the binding being reversible and competitive with the native agonist prostaglandin D2(PGD2). The binding kinetics of QAW039 determined directly using [(3)H]-QAW039 revealed mean kinetic on (kon) and off (koff) values for QAW039 of 4.5 × 10(7)M(-1)min(-1)and 0.048 minute(-1), respectively. Importantly, thekoffof QAW039 (half-life = 14.4 minutes) was >7-fold slower than the slowest reference compound tested, AZD-1981. In functional studies, QAW039 behaved as an insurmountable antagonist of PGD2-stimulated [(35)S]-GTPγS activation, and its effects were not fully reversed by increasing concentrations of PGD2after an initial 15-minute incubation period. This behavior is consistent with its relatively slow dissociation from the human CRTh2 receptor. In contrast for the other ligands tested this time-dependent effect on maximal stimulation was fully reversed by the 15-minute time point, whereas QAW039's effects persisted for >180 minutes. All CRTh2 antagonists tested inhibited PGD2-stimulated human eosinophil shape change, but importantly QAW039 retained its potency in the whole-blood shape-change assay relative to the isolated shape change assay, potentially reflective of its relatively slower off rate from the CRTh2 receptor. QAW039 was also a potent inhibitor of PGD2-induced cytokine release in human Th2 cells. Slow CRTh2 antagonist dissociation could provide increased receptor coverage in the face of pathologic PGD2concentrations, which may be clinically relevant.


Subject(s)
Anti-Allergic Agents/pharmacology , Drugs, Investigational/pharmacology , Indoleacetic Acids/pharmacology , Pyridines/pharmacology , Receptors, Immunologic/antagonists & inhibitors , Receptors, Prostaglandin/antagonists & inhibitors , Th2 Cells/drug effects , Acetates/chemistry , Acetates/metabolism , Acetates/pharmacology , Animals , Anti-Allergic Agents/chemistry , Anti-Allergic Agents/metabolism , Binding, Competitive , CHO Cells , Cell Shape/drug effects , Cells, Cultured , Cricetulus , Drugs, Investigational/chemistry , Drugs, Investigational/metabolism , Eosinophils/cytology , Eosinophils/drug effects , Eosinophils/immunology , Eosinophils/metabolism , Humans , Indoleacetic Acids/chemistry , Indoleacetic Acids/metabolism , Indoles/chemistry , Indoles/metabolism , Indoles/pharmacology , Kinetics , Ligands , Prostaglandin D2/antagonists & inhibitors , Prostaglandin D2/metabolism , Pyridines/chemistry , Pyridines/metabolism , Receptors, Immunologic/agonists , Receptors, Immunologic/genetics , Receptors, Immunologic/metabolism , Receptors, Prostaglandin/agonists , Receptors, Prostaglandin/genetics , Receptors, Prostaglandin/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Solubility , Th2 Cells/cytology , Th2 Cells/immunology , Th2 Cells/metabolism , Tritium
10.
N Engl J Med ; 369(5): 407-16, 2013 Aug 01.
Article in English | MEDLINE | ID: mdl-23782161

ABSTRACT

BACKGROUND: In September 2012, the World Health Organization reported the first cases of pneumonia caused by the novel Middle East respiratory syndrome coronavirus (MERS-CoV). We describe a cluster of health care-acquired MERS-CoV infections. METHODS: Medical records were reviewed for clinical and demographic information and determination of potential contacts and exposures. Case patients and contacts were interviewed. The incubation period and serial interval (the time between the successive onset of symptoms in a chain of transmission) were estimated. Viral RNA was sequenced. RESULTS: Between April 1 and May 23, 2013, a total of 23 cases of MERS-CoV infection were reported in the eastern province of Saudi Arabia. Symptoms included fever in 20 patients (87%), cough in 20 (87%), shortness of breath in 11 (48%), and gastrointestinal symptoms in 8 (35%); 20 patients (87%) presented with abnormal chest radiographs. As of June 12, a total of 15 patients (65%) had died, 6 (26%) had recovered, and 2 (9%) remained hospitalized. The median incubation period was 5.2 days (95% confidence interval [CI], 1.9 to 14.7), and the serial interval was 7.6 days (95% CI, 2.5 to 23.1). A total of 21 of the 23 cases were acquired by person-to-person transmission in hemodialysis units, intensive care units, or in-patient units in three different health care facilities. Sequencing data from four isolates revealed a single monophyletic clade. Among 217 household contacts and more than 200 health care worker contacts whom we identified, MERS-CoV infection developed in 5 family members (3 with laboratory-confirmed cases) and in 2 health care workers (both with laboratory-confirmed cases). CONCLUSIONS: Person-to-person transmission of MERS-CoV can occur in health care settings and may be associated with considerable morbidity. Surveillance and infection-control measures are critical to a global public health response.


Subject(s)
Coronavirus Infections/transmission , Coronavirus/genetics , Cross Infection/transmission , Disease Outbreaks , Pneumonia, Viral/epidemiology , Adult , Aged , Aged, 80 and over , Base Sequence , Coronavirus/isolation & purification , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Cross Infection/epidemiology , Cross Infection/virology , DNA, Viral/analysis , Disease Transmission, Infectious , Female , Humans , Infectious Disease Incubation Period , Infectious Disease Transmission, Patient-to-Professional , Intensive Care Units , Male , Middle Aged , Phylogeny , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Renal Dialysis , Saudi Arabia/epidemiology
11.
J Virol ; 89(10): 5222-37, 2015 May.
Article in English | MEDLINE | ID: mdl-25787276

ABSTRACT

UNLABELLED: Epstein-Barr virus (EBV) infects most of the world's population and is causally associated with several human cancers, but little is known about how EBV genetic variation might influence infection or EBV-associated disease. There are currently no published wild-type EBV genome sequences from a healthy individual and very few genomes from EBV-associated diseases. We have sequenced 71 geographically distinct EBV strains from cell lines, multiple types of primary tumor, and blood samples and the first EBV genome from the saliva of a healthy carrier. We show that the established genome map of EBV accurately represents all strains sequenced, but novel deletions are present in a few isolates. We have increased the number of type 2 EBV genomes sequenced from one to 12 and establish that the type 1/type 2 classification is a major feature of EBV genome variation, defined almost exclusively by variation of EBNA2 and EBNA3 genes, but geographic variation is also present. Single nucleotide polymorphism (SNP) density varies substantially across all known open reading frames and is highest in latency-associated genes. Some T-cell epitope sequences in EBNA3 genes show extensive variation across strains, and we identify codons under positive selection, both important considerations for the development of vaccines and T-cell therapy. We also provide new evidence for recombination between strains, which provides a further mechanism for the generation of diversity. Our results provide the first global view of EBV sequence variation and demonstrate an effective method for sequencing large numbers of genomes to further understand the genetics of EBV infection. IMPORTANCE: Most people in the world are infected by Epstein-Barr virus (EBV), and it causes several human diseases, which occur at very different rates in different parts of the world and are linked to host immune system variation. Natural variation in EBV DNA sequence may be important for normal infection and for causing disease. Here we used rapid, cost-effective sequencing to determine 71 new EBV sequences from different sample types and locations worldwide. We showed geographic variation in EBV genomes and identified the most variable parts of the genome. We identified protein sequences that seem to have been selected by the host immune system and detected variability in known immune epitopes. This gives the first overview of EBV genome variation, important for designing vaccines and immune therapy for EBV, and provides techniques to investigate relationships between viral sequence variation and EBV-associated diseases.


Subject(s)
Epstein-Barr Virus Infections/virology , Genetic Variation , Genome, Viral , Herpesvirus 4, Human/genetics , Amino Acid Sequence , Antigens, Viral/genetics , Carrier State/virology , Cell Line, Tumor , DNA, Viral/genetics , Epitopes, T-Lymphocyte/genetics , Epstein-Barr Virus Nuclear Antigens/genetics , Herpesvirus 4, Human/classification , Herpesvirus 4, Human/isolation & purification , Humans , Phylogeny , Polymorphism, Single Nucleotide , Recombination, Genetic , Viral Matrix Proteins/genetics
12.
J Virol ; 89(19): 9920-31, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26202246

ABSTRACT

UNLABELLED: The emergence in humans of the A(H1N1)pdm09 influenza virus, a complex reassortant virus of swine origin, highlighted the importance of worldwide influenza virus surveillance in swine. To date, large-scale surveillance studies have been reported for southern China and North America, but such data have not yet been described for Europe. We report the first large-scale genomic characterization of 290 swine influenza viruses collected from 14 European countries between 2009 and 2013. A total of 23 distinct genotypes were identified, with the 7 most common comprising 82% of the incidence. Contrasting epidemiological dynamics were observed for two of these genotypes, H1huN2 and H3N2, with the former showing multiple long-lived geographically isolated lineages, while the latter had short-lived geographically diffuse lineages. At least 32 human-swine transmission events have resulted in A(H1N1)pdm09 becoming established at a mean frequency of 8% across European countries. Notably, swine in the United Kingdom have largely had a replacement of the endemic Eurasian avian virus-like ("avian-like") genotypes with A(H1N1)pdm09-derived genotypes. The high number of reassortant genotypes observed in European swine, combined with the identification of a genotype similar to the A(H3N2)v genotype in North America, underlines the importance of continued swine surveillance in Europe for the purposes of maintaining public health. This report further reveals that the emergences and drivers of virus evolution in swine differ at the global level. IMPORTANCE: The influenza A(H1N1)pdm09 virus contains a reassortant genome with segments derived from separate virus lineages that evolved in different regions of the world. In particular, its neuraminidase and matrix segments were derived from the Eurasian avian virus-like ("avian-like") lineage that emerged in European swine in the 1970s. However, while large-scale genomic characterization of swine has been reported for southern China and North America, no equivalent study has yet been reported for Europe. Surveillance of swine herds across Europe between 2009 and 2013 revealed that the A(H1N1)pdm09 virus is established in European swine, increasing the number of circulating lineages in the region and increasing the possibility of the emergence of a genotype with human pandemic potential. It also has implications for veterinary health, making prevention through vaccination more challenging. The identification of a genotype similar to the A(H3N2)v genotype, causing zoonoses at North American agricultural fairs, underlines the importance of continued genomic characterization in European swine.


Subject(s)
Influenza A virus/genetics , Orthomyxoviridae Infections/veterinary , Sus scrofa/virology , Swine Diseases/epidemiology , Swine Diseases/virology , Animals , Epidemiological Monitoring/veterinary , Europe/epidemiology , Evolution, Molecular , Genotype , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H1N2 Subtype/genetics , Influenza A Virus, H1N2 Subtype/isolation & purification , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza A virus/isolation & purification , Influenza, Human/epidemiology , Influenza, Human/virology , Molecular Epidemiology , Orthomyxoviridae Infections/epidemiology , Orthomyxoviridae Infections/virology , Phylogeny , Reassortant Viruses/genetics , Swine
13.
Proc Biol Sci ; 282(1808): 20150418, 2015 Jun 07.
Article in English | MEDLINE | ID: mdl-25994675

ABSTRACT

Many studies have focused on the impacts of climate change on biological assemblages, yet little is known about how climate interacts with other major anthropogenic influences on biodiversity, such as habitat disturbance. Using a unique global database of 1128 local ant assemblages, we examined whether climate mediates the effects of habitat disturbance on assemblage structure at a global scale. Species richness and evenness were associated positively with temperature, and negatively with disturbance. However, the interaction among temperature, precipitation and disturbance shaped species richness and evenness. The effect was manifested through a failure of species richness to increase substantially with temperature in transformed habitats at low precipitation. At low precipitation levels, evenness increased with temperature in undisturbed sites, peaked at medium temperatures in disturbed sites and remained low in transformed sites. In warmer climates with lower rainfall, the effects of increasing disturbance on species richness and evenness were akin to decreases in temperature of up to 9°C. Anthropogenic disturbance and ongoing climate change may interact in complicated ways to shape the structure of assemblages, with hot, arid environments likely to be at greatest risk.


Subject(s)
Ants/physiology , Biodiversity , Climate , Animals , Climate Change , Temperature
14.
J Virol ; 88(19): 11056-69, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25056894

ABSTRACT

UNLABELLED: Norovirus is a highly transmissible infectious agent that causes epidemic gastroenteritis in susceptible children and adults. Norovirus infections can be severe and can be initiated from an exceptionally small number of viral particles. Detailed genome sequence data are useful for tracking norovirus transmission and evolution. To address this need, we have developed a whole-genome deep-sequencing method that generates entire genome sequences from small amounts of clinical specimens. This novel approach employs an algorithm for reverse transcription and PCR amplification primer design using all of the publically available norovirus sequence data. Deep sequencing and de novo assembly were used to generate norovirus genomes from a large set of diarrheal patients attending three hospitals in Ho Chi Minh City, Vietnam, over a 2.5-year period. Positive-selection analysis and direct examination of protein changes in the virus over time identified codons in the regions encoding proteins VP1, p48 (NS1-2), and p22 (NS4) under positive selection and expands the known targets of norovirus evolutionary pressure. IMPORTANCE: The high transmissibility and rapid evolutionary rate of norovirus, combined with a short-lived host immune responses, are thought to be the reasons why the virus causes the majority of pediatric viral diarrhea cases. The evolutionary patterns of this RNA virus have been described in detail for only a portion of the virus genome and never for a virus from a detailed urban tropical setting. We provide a detailed sequence description of the noroviruses circulating in three Ho Chi Minh City hospitals over a 2.5-year period. This study identified patterns of virus change in known sites of host immune response and identified three additional regions of the virus genome under selection that were not previously recognized. In addition, the method described here provides a robust full-genome sequencing platform for community-based virus surveillance.


Subject(s)
Genome, Viral , High-Throughput Nucleotide Sequencing/methods , Norovirus/genetics , Phylogeny , RNA, Viral/genetics , Biological Evolution , Caliciviridae Infections/virology , Child , Child, Preschool , Cities , Codon , Diarrhea/virology , Gastroenteritis/virology , Gene Expression , Humans , Infant , Norovirus/classification , Norovirus/isolation & purification , Vietnam , Viral Nonstructural Proteins/genetics
15.
J Virol ; 88(22): 13269-83, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25210166

ABSTRACT

UNLABELLED: The influenza pandemic that emerged in 2009 provided an unprecedented opportunity to study adaptation of a virus recently acquired from an animal source during human transmission. In the United Kingdom, the novel virus spread in three temporally distinct waves between 2009 and 2011. Phylogenetic analysis of complete viral genomes showed that mutations accumulated over time. Second- and third-wave viruses replicated more rapidly in human airway epithelial (HAE) cells than did the first-wave virus. In infected mice, weight loss varied between viral isolates from the same wave but showed no distinct pattern with wave and did not correlate with viral load in the mouse lungs or severity of disease in the human donor. However, second- and third-wave viruses induced less alpha interferon in the infected mouse lungs. NS1 protein, an interferon antagonist, had accumulated several mutations in second- and third-wave viruses. Recombinant viruses with the third-wave NS gene induced less interferon in human cells, but this alone did not account for increased virus fitness in HAE cells. Mutations in HA and NA genes in third-wave viruses caused increased binding to α-2,6-sialic acid and enhanced infectivity in human mucus. A recombinant virus with these two segments replicated more efficiently in HAE cells. A mutation in PA (N321K) enhanced polymerase activity of third-wave viruses and also provided a replicative advantage in HAE cells. Therefore, multiple mutations allowed incremental changes in viral fitness, which together may have contributed to the apparent increase in severity of A(H1N1)pdm09 influenza virus during successive waves. IMPORTANCE: Although most people infected with the 2009 pandemic influenza virus had mild or unapparent symptoms, some suffered severe and devastating disease. The reasons for this variability were unknown, but the numbers of severe cases increased during successive waves of human infection in the United Kingdom. To determine the causes of this variation, we studied genetic changes in virus isolates from individual hospitalized patients. There were no consistent differences between these viruses and those circulating in the community, but we found multiple evolutionary changes that in combination over time increased the virus's ability to infect human cells. These adaptations may explain the remarkable ability of A(H1N1)pdm09 virus to continue to circulate despite widespread immunity and the apparent increase in severity of influenza over successive waves of infection.


Subject(s)
Adaptation, Biological , Influenza A Virus, H1N1 Subtype/genetics , Influenza, Human/virology , Mutation , Adolescent , Adult , Animals , Child , Child, Preschool , Disease Models, Animal , Female , Genome, Viral , Humans , Infant , Infant, Newborn , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza, Human/epidemiology , Interferons/metabolism , Lung/immunology , Lung/pathology , Lung/virology , Male , Mice, Inbred BALB C , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/pathology , Orthomyxoviridae Infections/virology , Phylogeny , RNA, Viral , Sequence Analysis, DNA , United Kingdom/epidemiology , Virus Attachment , Virus Replication , Young Adult
16.
J Infect Dis ; 210(10): 1590-4, 2014 Nov 15.
Article in English | MEDLINE | ID: mdl-24837403

ABSTRACT

BACKGROUND: Analysis of clinical samples from patients with new viral infections is critical to confirm the diagnosis, to specify the viral load, and to sequence data necessary for characterizing the viral kinetics, transmission, and evolution. We analyzed samples from 112 patients infected with the recently discovered Middle East respiratory syndrome coronavirus (MERS-CoV). METHODS: Respiratory tract samples from cases of MERS-CoV infection confirmed by polymerase chain reaction (PCR) were investigated to determine the MERS-CoV load and fraction of the MERS-CoV genome. These values were analyzed to determine associations with clinical sample type. RESULTS: Samples from 112 individuals in which MERS-CoV was detected by PCR were analyzed, of which 13 were sputum samples, 64 were nasopharyngeal swab specimens, 30 were tracheal aspirates, and 3 were bronchoalveolar lavage specimens; 2 samples were of unknown origin. Tracheal aspirates yielded significantly higher MERS-CoV loads, compared with nasopharyngeal swab specimens (P = .005) and sputum specimens (P = .0001). Tracheal aspirates had viral loads similar to those in bronchoalveolar lavage samples (P = .3079). Bronchoalveolar lavage samples and tracheal aspirates had significantly higher genome fraction than nasopharyngeal swab specimens (P = .0095 and P = .0002, respectively) and sputum samples (P = .0009 and P = .0001, respectively). The genome yield from tracheal aspirates and bronchoalveolar lavage samples were similar (P = .1174). CONCLUSIONS: Lower respiratory tract samples yield significantly higher MERS-CoV loads and genome fractions than upper respiratory tract samples.


Subject(s)
Coronavirus Infections/pathology , Coronavirus Infections/virology , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Respiratory System/virology , Viral Load , Humans , Polymerase Chain Reaction
17.
Emerg Infect Dis ; 20(6): 1012-5, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24857749

ABSTRACT

We investigated a case of human infection with Middle East respiratory syndrome coronavirus (MERS-CoV) after exposure to infected camels. Analysis of the whole human-derived virus and 15% of the camel-derived virus sequence yielded nucleotide polymorphism signatures suggestive of cross-species transmission. Camels may act as a direct source of human MERS-CoV infection.


Subject(s)
Camelus/virology , Coronavirus Infections/diagnosis , Coronavirus Infections/transmission , Middle East Respiratory Syndrome Coronavirus/genetics , Adult , Animals , Coronavirus Infections/virology , High-Throughput Nucleotide Sequencing , Humans , Male , Middle East Respiratory Syndrome Coronavirus/classification , Middle East Respiratory Syndrome Coronavirus/isolation & purification
18.
Lancet ; 382(9909): 1993-2002, 2013 Dec 14.
Article in English | MEDLINE | ID: mdl-24055451

ABSTRACT

BACKGROUND: Since June, 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) has, worldwide, caused 104 infections in people including 49 deaths, with 82 cases and 41 deaths reported from Saudi Arabia. In addition to confirming diagnosis, we generated the MERS-CoV genomic sequences obtained directly from patient samples to provide important information on MERS-CoV transmission, evolution, and origin. METHODS: Full genome deep sequencing was done on nucleic acid extracted directly from PCR-confirmed clinical samples. Viral genomes were obtained from 21 MERS cases of which 13 had 100%, four 85-95%, and four 30-50% genome coverage. Phylogenetic analysis of the 21 sequences, combined with nine published MERS-CoV genomes, was done. FINDINGS: Three distinct MERS-CoV genotypes were identified in Riyadh. Phylogeographic analyses suggest the MERS-CoV zoonotic reservoir is geographically disperse. Selection analysis of the MERS-CoV genomes reveals the expected accumulation of genetic diversity including changes in the S protein. The genetic diversity in the Al-Hasa cluster suggests that the hospital outbreak might have had more than one virus introduction. INTERPRETATION: We present the largest number of MERS-CoV genomes (21) described so far. MERS-CoV full genome sequences provide greater detail in tracking transmission. Multiple introductions of MERS-CoV are identified and suggest lower R0 values. Transmission within Saudi Arabia is consistent with either movement of an animal reservoir, animal products, or movement of infected people. Further definition of the exposures responsible for the sporadic introductions of MERS-CoV into human populations is urgently needed. FUNDING: Saudi Arabian Ministry of Health, Wellcome Trust, European Community, and National Institute of Health Research University College London Hospitals Biomedical Research Centre.


Subject(s)
Coronavirus Infections/genetics , Coronavirus/genetics , Disease Outbreaks , Evolution, Molecular , Genome, Viral , Respiratory Tract Infections/genetics , Base Sequence , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Gene Amplification , Humans , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/transmission , Saudi Arabia/epidemiology , Syndrome
19.
Bioorg Med Chem Lett ; 24(1): 72-6, 2014 Jan 01.
Article in English | MEDLINE | ID: mdl-24332493

ABSTRACT

A hit-to-lead optimisation programme was carried out on the Novartis archive screening hit, pyrazolopyrimidine 2-methyl-5-((phenylthio)methyl)pyrazolo[1,5-a]pyrimidin-7-ol 1, resulting in the discovery of CXCR2 receptor antagonist 2-benzyl-5-(((2,3-difluorophenyl)thio)methyl)-[1,2,4]triazolo[1,5-a]pyrimidin-7-ol 14. The SAR was investigated by systematic variation of the pendant thiol, alkyl and pyrimidinol groups. Replacement of the pyrazolopyrimidine core with a triazolo alternative led to a dual series of antagonists with favourable biological and pharmacokinetic properties.


Subject(s)
Drug Discovery , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Receptors, CCR2/antagonists & inhibitors , Administration, Oral , Biological Availability , Dose-Response Relationship, Drug , Humans , Molecular Structure , Pyrazoles/chemical synthesis , Pyrazoles/chemistry , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Structure-Activity Relationship
20.
J R Coll Physicians Edinb ; 54(1): 55-58, 2024 03.
Article in English | MEDLINE | ID: mdl-38499459

ABSTRACT

Digoxin toxicity can be life-threatening. Digoxin-specific antibody (DSA) fragments are used in severe digoxin toxicity, binding to serum-free digoxin and enabling increased renal excretion. In severe renal impairment, clearance of these complexes is prolonged, leading to rebound toxicity. Digoxin and DSA complexes are not dialysable. We present a case of a gentleman with severe digoxin toxicity and acute kidney injury (AKI). Despite receiving DSA doses, his digoxin levels rebounded and symptoms persisted. Based on published case reports, plasma exchange (PEX) after further dosing was arranged. PEX facilitated the removal of digoxin-DSA complexes, bypassing renal excretion. During PEX, clinical signs improved and were sustained. He did not require further dialysis or PEX, renal function recovered and he was discharged. This case highlights challenges in the management of severe digoxin toxicity in patients with a concurrent AKI. The use of PEX enabled digoxin-DSA complex removal and should be considered in these circumstances.


Subject(s)
Acute Kidney Injury , Plasma Exchange , Humans , Male , Acute Kidney Injury/chemically induced , Acute Kidney Injury/therapy , Digoxin/adverse effects , Renal Dialysis , Aged, 80 and over
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