Journals
2012 EN
Jayne Green · Dong Wang · Catherine J. Lilley
+2 more
Current and future global crop yields depend upon soil quality to which soil organisms make an important contribution. The European Union seeks to protect European soils and their biodiversity for instance by amending its Directive on pesticide usage. This poses a challenge for control of Globodera pallida (a potato cyst nematode) for which both natural resistance and rotational control are inadequate. One approach of high potential is transgenically based resistance. This work demonstrates the potential in the field of a new transgenic trait for control of G. pallida that suppresses root invasion. It also investigates its impact and that of a second transgenic trait on the non-target soil nematode community. We establish that a peptide that disrupts chemoreception of nematodes without a lethal effect provides resistance to G. pallida in both a containment and a field trial when precisely targeted under control of a root tip-specific promoter. In addition we combine DNA barcoding and quantitative PCR to recognise nematode genera from soil samples without microscope-based observation and use the method for nematode faunal analysis. This approach establishes that the peptide and a cysteine proteinase inhibitor that offer distinct bases for transgenic plant resistance to G. pallida do so without impact on the non-target nematode soil community.
Public Library of Science
Journals
2012 EN
Coralie Chevallier · Catherine Molesworth · Francesca Happé
Human beings are endowed with a unique motivation to be included in social interactions. This natural social motivation, in turn, is thought to encourage behaviours such as flattery or self-deprecation aimed to ease interaction and to enhance the reputation of the individual who produces them. If this is the case, diminished social interest should affect reputation management. Here, we use Autism Spectrum Disorders (ASDs) –primarily characterised by pervasive social disinterest– as a model to investigate the effect of social motivation on reputation management. Children first rated a set of pictures and were then given the opportunity to inflate their initial ratings in front of an experimenter who declared that she had drawn the picture. Contrary to the controls, children with ASD did not enhance their ratings in the drawer's presence. Moreover, participants' flattery behaviour correlated with self-reports of social enjoyment. Our findings point to a link between diminished social interest and reputation management.
Public Library of Science
Journals
2012 EN
Marie Pagès · Pascale Chevret · Muriel GrosBalthazard
+6 more
Background The lava mouse, Malpaisomys insularis , was endemic to the Eastern Canary islands and became extinct at the beginning of the 14 th century when the Europeans reached the archipelago. Studies to determine Malpaisomys' phylogenetic affinities, based on morphological characters, remained inconclusive because morphological changes experienced by this insular rodent make phylogenetic investigations a real challenge. Over 20 years since its first description, Malpaisomys' phylogenetic position remains enigmatic. Methodology/Principal Findings In this study, we resolved this issue using molecular characters. Mitochondrial and nuclear markers were successfully amplified from subfossils of three lava mouse samples. Molecular phylogenetic reconstructions revealed, without any ambiguity, unsuspected relationships between Malpaisomys and extant mice (genus Mus , Murinae). Moreover, through molecular dating we estimated the origin of the Malpaisomys /mouse clade at 6.9 Ma, corresponding to the maximal age at which the archipelago was colonised by the Malpaisomys ancestor via natural rafting. Conclusion/Significance This study reconsiders the derived morphological characters of Malpaisomys in light of this unexpected molecular finding. To reconcile molecular and morphological data, we propose to consider Malpaisomys insularis as an insular lineage of mouse.
Public Library of Science
Journals
2012 EN
Karen Edmond · Susana Scott · Viola Korczak
+7 more
Background The risks of long term sequelae from childhood pneumonia have not been systematically assessed. The aims of this study were to: (i) estimate the risks of respiratory sequelae after pneumonia in children under five years; (ii) estimate the distribution of the different types of respiratory sequelae; and (iii) compare sequelae risk by hospitalisation status and pathogen. Methods We systematically reviewed published papers from 1970 to 2011. Standard global burden of disease categories (restrictive lung disease, obstructive lung disease, bronchiectasis) were labelled as major sequelae. ‘Minor’ sequelae (chronic bronchitis, asthma, other abnormal pulmonary function, other respiratory disease), and multiple impairments were also included. Thirteen papers were selected for inclusion. Synthesis was by random effects meta-analysis and meta-regression. Results Risk of at least one major sequelae was 5.5% (95% confidence interval [95% CI] 2.8–8.3%) in non hospitalised children and 13.6% [6.2–21.1%]) in hospitalised children. Adenovirus pneumonia was associated with the highest sequelae risk (54.8% [39.2–70.5%]) but children hospitalised with no pathogen isolated also had high risk (17.6% [10.9–24.3%]). The most common type of major sequela was restrictive lung disease (5.4% [2.5–10.2%]) . Potential confounders such as loss to follow up and median age at infection were not associated with sequelae risk in the final models. Conclusions All children with pneumonia diagnosed by a health professional should be considered at risk of long term sequelae. Evaluation of childhood pneumonia interventions should include potential impact on long term respiratory sequelae.
Public Library of Science
Journals
2012 EN
Li Liu · Valérie Drouet · Jessica Wu
+4 more
Tauopathy in the brain of patients with Alzheimer's disease starts in the entorhinal cortex (EC) and spreads anatomically in a defined pattern. To test whether pathology initiating in the EC spreads through the brain along synaptically connected circuits, we have generated a transgenic mouse model that differentially expresses pathological human tau in the EC and we have examined the distribution of tau pathology at different timepoints. In relatively young mice (10–11 months old), human tau was present in some cell bodies, but it was mostly observed in axons within the superficial layers of the medial and lateral EC, and at the terminal zones of the perforant pathway. In old mice (>22 months old), intense human tau immunoreactivity was readily detected not only in neurons in the superficial layers of the EC, but also in the subiculum, a substantial number of hippocampal pyramidal neurons especially in CA1, and in dentate gyrus granule cells. Scattered immunoreactive neurons were also seen in the deeper layers of the EC and in perirhinal and secondary somatosensory cortex. Immunoreactivity with the conformation-specific tau antibody MC1 correlated with the accumulation of argyrophilic material seen in old, but not young mice. In old mice, axonal human tau immunoreactivity, especially at the endzones of the perforant pathway, was greatly reduced. Relocalization of tau from axons to somatodendritic compartments and propagation of tauopathy to regions outside of the EC correlated with mature tangle formation in neurons in the EC as revealed by thioflavin-S staining. Our data demonstrate propagation of pathology from the EC and support a trans-synaptic mechanism of spread along anatomically connected networks, between connected and vulnerable neurons. In general, the mouse recapitulates the tauopathy that defines the early stages of AD and provides a model for testing mechanisms and functional outcomes associated with disease progression.
Public Library of Science
Journals
2012 EN
Catherine G. Sutcliffe · Tamaki Kobayashi · Harry Hamapumbu
+6 more
Background In regions of declining malaria transmission, new strategies for control are needed to reduce transmission and achieve elimination. Artemisinin-combination therapy (ACT) is active against immature gametocytes and can reduce the risk of transmission. We sought to determine whether household screening and treatment of infected individuals provides protection against infection for household members. Methodology/Principal Findings The study was conducted in two areas in Southern Province, Zambia in 2007 and 2008/2009. To determine the impact of proactive case detection, households were randomly selected either to join a longitudinal cohort, in which participants were repeatedly screened throughout the year and those infected treated with artemether-lumefantrine, or a cross-sectional survey, in which participants were visited only once. Cross-sectional surveys were conducted throughout the year. The prevalence of RDT positivity was compared between the longitudinal and cross-sectional households at baseline and during follow-up using multilevel logistic regression. In the 2007 study area, 174 and 156 participants enrolled in the cross-sectional and longitudinal groups, respectively. In the 2008/2009 study area, 917 and 234 participants enrolled in the cross-sectional and longitudinal groups, respectively. In both study areas, participants and households in the longitudinal and cross-sectional groups were similar on demographic characteristics and prevalence of RDT positivity at baseline (2007: OR = 0.97; 95% CI:0.46, 2.03 | 2008/2009: OR = 1.28; 95% CI:0.44, 3.79). After baseline, the prevalence of RDT positivity was significantly lower in longitudinal compared to cross-sectional households in both study areas (2007: OR = 0.44; 95% CI:0.20, 0.96 | 2008/2009: OR = 0.16; 95% CI:0.05, 0.55). Conclusions/Significance Proactive case detection, consisting of screening household members with an RDT and treating those positive with ACT, can reduce transmission and provide indirect protection to household members. A targeted test and treat strategy could contribute to the elimination of malaria in regions of low transmission.
Public Library of Science
Journals
2012 EN
Catherine E. Dana · Kristine M. Glauber · Titus Chan
+2 more
Genome sequencing has revealed examples of horizontally transferred genes, but we still know little about how such genes are incorporated into their host genomes. We have previously reported the identification of a gene ( flp ) that appears to have entered the Hydra genome through horizontal transfer. Here we provide additional evidence in support of our original hypothesis that the transfer was from a unicellular organism, and we show that the transfer occurred in an ancestor of two medusozoan cnidarian species. In addition we show that the gene is part of a bicistronic operon in the Hydra genome. These findings identify a new animal phylum in which trans-spliced leader addition has led to the formation of operons, and define the requirements for evolution of an operon in Hydra . The identification of operons in Hydra also provides a tool that can be exploited in the construction of transgenic Hydra strains.
Public Library of Science
Journals
2012 EN
Catherine Linard · Marius Gilbert · Robert W. Snow
+2 more
The spatial distribution of populations and settlements across a country and their interconnectivity and accessibility from urban areas are important for delivering healthcare, distributing resources and economic development. However, existing spatially explicit population data across Africa are generally based on outdated, low resolution input demographic data, and provide insufficient detail to quantify rural settlement patterns and, thus, accurately measure population concentration and accessibility. Here we outline approaches to developing a new high resolution population distribution dataset for Africa and analyse rural accessibility to population centers. Contemporary population count data were combined with detailed satellite-derived settlement extents to map population distributions across Africa at a finer spatial resolution than ever before. Substantial heterogeneity in settlement patterns, population concentration and spatial accessibility to major population centres is exhibited across the continent. In Africa, 90% of the population is concentrated in less than 21% of the land surface and the average per-person travel time to settlements of more than 50,000 inhabitants is around 3.5 hours, with Central and East Africa displaying the longest average travel times. The analyses highlight large inequities in access, the isolation of many rural populations and the challenges that exist between countries and regions in providing access to services. The datasets presented are freely available as part of the AfriPop project, providing an evidence base for guiding strategic decisions.
Public Library of Science
Journals
2012 EN
Mamadou Ousmane Ndiath · Seynabou Sougoufara · Abdoulaye Gaye
+5 more
The aim of this study was to evaluate the susceptibility to insecticides of An. gambiae mosquitoes sampled in Dielmo (Senegal), in 2010, 2 years after the implementation of Long Lasting Insecticide-treated Nets (LLINs) and to report the evolution of kdr mutation frequency from 2006 to 2010. Methods WHO bioassay susceptibility tests to 6 insecticides were performed on adults F0, issuing from immature stages of An. gambiae s.l., sampled in August 2010. Species and molecular forms as well as the presence of L1014F and L1014S kdr mutations were assessed by PCR. Longitudinal study of kdr mutations was performed on adult mosquitoes sampled monthly by night landing catches from 2006 to 2010. Findings No specimen studied presented the L1014S mutation. During the longitudinal study, L1014F allelic frequency rose from 2.4% in year before the implementation of LLINs to 4.6% 0–12 months after and 18.7% 13–30 months after. In 2010, An. gambiae were resistant to DDT, Lambda-cyhalothrin, Deltamethrin and Permethrin (mortality rates ranging from 46 to 63%) but highly susceptible to Fenitrothion and Bendiocarb (100% mortality). There was significantly more RR genotype among An. gambiae surviving exposure to DDT or Pyrethroids. An. arabiensis represented 3.7% of the sampled mosquitoes (11/300) with no kdr resistance allele detected. An. gambiae molecular form M represented 29.7% of the mosquitoes with, among them, kdr genotypes SR (18%) and SS (82%). An. gambiae molecular form S represented 66% of the population with, among them, kdr genotype SS (33.3%), SR (55.6%) and RR (11.1%). Only 2 MS hybrid mosquitoes were sampled and presented SS kdr genotype. Conclusion Biological evidence of resistance to DDT and pyrethroids was detected among An. gambiae mosquitoes in Dielmo (Senegal) within 24 months of community use of LLINs. Molecular identification of L1014F mutation indicated that target site resistance increased after the implementation of LLINs.
Public Library of Science
Journals
2012 EN
Haifeng Yin · Catherine O. Copley · Lisa V. Goodrich
+1 more
Experiments utilizing the Looptail mutant mouse, which harbors a missense mutation in the vangl2 gene, have been essential for studies of planar polarity and linking the function of the core planar cell polarity proteins to other developmental signals. Originally described as having dominant phenotypic traits, the molecular interactions underlying the Looptail mutant phenotype are unclear because Vangl2 protein levels are significantly reduced or absent from mutant tissues. Here we introduce a vangl2 knockout mouse and directly compare the severity of the knockout and Looptail mutant phenotypes by intercrossing the two lines and assaying the planar polarity of inner ear hair cells. Overall the vangl2 knockout phenotype is milder than the phenotype of compound mutants carrying both the Looptail and vangl2 knockout alleles. In compound mutants a greater number of hair cells are affected and changes in the orientation of individual hair cells are greater when quantified. We further demonstrate in a heterologous cell system that the protein encoded by the Looptail mutation (Vangl2 S464N ) disrupts delivery of Vangl1 and Vangl2 proteins to the cell surface as a result of oligomer formation between Vangl1 and Vangl2 S464N , or Vangl2 and Vangl2 S464N , coupled to the intracellular retention of Vangl2 S464N . As a result, Vangl1 protein is missing from the apical cell surface of vestibular hair cells in Looptail mutants, but is retained at the apical cell surface of hair cells in vangl2 knockouts. Similarly the distribution of Prickle-like2, a putative Vangl2 interacting protein, is differentially affected in the two mutant lines. In summary, we provide evidence for a direct physical interaction between Vangl1 and Vangl2 through a combination of in vitro and in vivo approaches and propose that this interaction underlies the dominant phenotypic traits associated with the Looptail mutation.
Public Library of Science