Quaternary Structure Defines a Large Class of Amyloid-β Oligomers Neutralized by Sequestration

SummaryThe accumulation of amyloid-β (Aβ) as amyloid fibrils and toxic oligomers is an important step in the development of Alzheimer’s disease (AD). However, there are numerous potentially toxic oligomers and little is known about their neurological effects when generated in the living brain. Here we show that Aβ oligomers can be assigned to one of at least two classes (type 1 and type 2) based on their temporal, spatial, and structural relationships to amyloid fibrils. The type 2 oligomers are related to amyloid fibrils and represent the majority of oligomers generated in vivo, but they remain confined to the vicinity of amyloid plaques and do not impair cognition at levels relevant to AD. Type 1 oligomers are unrelated to amyloid fibrils and may have greater potential to cause global neural dysfunction in AD because they are dispersed. These results refine our understanding of the pathogenicity of Aβ oligomers in vivo

Respiratory syncytial, parainfluenza and influenza virus infection in young children with acute lower respiratory infection in rural Gambia.

Respiratory viral infections contribute significantly to morbidity and mortality worldwide, but representative data from sub-Saharan Africa are needed to inform vaccination strategies. We conducted population-based surveillance in rural Gambia using standardized criteria to identify and investigate children with acute lower respiratory infection (ALRI). Naso- and oropharyngeal swabs were collected. Each month from February through December 2015, specimens from 50 children aged 2-23 months were randomly selected to test for respiratory syncytial (RSV), parainfluenza (PIV) and influenza viruses. The expected number of viral-associated ALRI cases in the population was estimated using statistical simulation that accounted for the sampling design. RSV G and F proteins and influenza hemagglutinin genes were sequenced. 2385 children with ALRI were enrolled, 519 were randomly selected for viral testing. One or more viruses were detected in 303/519 children (58.4%). RSV-A was detected in 237 and RSV-B in seven. The expected incidence of ALRI associated with RSV, PIV or influenza was 140 cases (95% CI, 131-149) per 1000 person-years; RSV incidence was 112 cases (95% CI, 102-122) per 1000 person-years. Multiple strains of RSV and influenza circulated during the year. RSV circulated throughout most of the year and was associated with eight times the number of ALRI cases compared to PIV or IV. Gambian RSV viruses were closely related to viruses detected in other continents. An effective RSV vaccination strategy could have a major impact on the burden of ALRI in this setting

Organisational and student characteristics, fidelity, funding models, and unit costs of recovery colleges in 28 countries:a cross-sectional survey

Background: Recovery colleges were developed in England to support the recovery of individuals who have mental health symptoms or mental illness. They have been founded in many countries but there has been little international research on recovery colleges and no studies investigating their staffing, fidelity, or costs. We aimed to characterise recovery colleges internationally, to understand organisational and student characteristics, fidelity, and budget. Methods: In this cross-sectional study, we identified all countries in which recovery colleges exist. We repeated a cross-sectional survey done in England for recovery colleges in 28 countries. In both surveys, recovery colleges were defined as services that supported personal recovery, that were coproduced with students and staff, and where students learned collaboratively with trainers. Recovery college managers completed the survey. The survey included questions about organisational and student characteristics, fidelity to the RECOLLECT Fidelity Measure, funding models, and unit costs. Recovery colleges were grouped by country and continent and presented descriptively. We used regression models to explore continental differences in fidelity, using England as the reference group. Findings: We identified 221 recovery colleges operating across 28 countries, in five continents. Overall, 174 (79%) of 221 recovery colleges participated. Most recovery colleges scored highly on fidelity. Overall scores for fidelity (β=–2·88, 95% CI 4·44 to –1·32; p=0·0001), coproduction (odds ratio [OR] 0·10, 95% CI 0·03 to 0·33; p&lt;0·0001), and being tailored to the student (OR 0·10, 0·02 to 0·39; p=0·0010), were lower for recovery colleges in Asia than in England. No other significant differences were identified between recovery colleges in England, and those in other continents where recovery colleges were present. 133 recovery colleges provided data on annual budgets, which ranged from €0 to €2 550 000, varying extensively within and between continents. From included data, all annual budgets reported by the college added up to €30 million, providing 19 864 courses for 55 161 students. Interpretation: Recovery colleges exist in many countries. There is an international consensus on key operating principles, especially equality and a commitment to recovery, and most recovery colleges achieve moderate to high fidelity to the original model, irrespective of the income band of their country. Cultural differences need to be considered in assessing coproduction and approaches to individualising support. Funding: National Institute for Health and Care Research.</p

Genome Fragmentation Is Not Confined to the Peridinin Plastid in Dinoflagellates

When plastids are transferred between eukaryote lineages through series of endosymbiosis, their environment changes dramatically. Comparison of dinoflagellate plastids that originated from different algal groups has revealed convergent evolution, suggesting that the host environment mainly influences the evolution of the newly acquired organelle. Recently the genome from the anomalously pigmented dinoflagellate Karlodinium veneficum plastid was uncovered as a conventional chromosome. To determine if this haptophyte-derived plastid contains additional chromosomal fragments that resemble the mini-circles of the peridin-containing plastids, we have investigated its genome by in-depth sequencing using 454 pyrosequencing technology, PCR and clone library analysis. Sequence analyses show several genes with significantly higher copy numbers than present in the chromosome. These genes are most likely extrachromosomal fragments, and the ones with highest copy numbers include genes encoding the chaperone DnaK(Hsp70), the rubisco large subunit (rbcL), and two tRNAs (trnE and trnM). In addition, some photosystem genes such as psaB, psaA, psbB and psbD are overrepresented. Most of the dnaK and rbcL sequences are found as shortened or fragmented gene sequences, typically missing the 3′-terminal portion. Both dnaK and rbcL are associated with a common sequence element consisting of about 120 bp of highly conserved AT-rich sequence followed by a trnE gene, possibly serving as a control region. Decatenation assays and Southern blot analysis indicate that the extrachromosomal plastid sequences do not have the same organization or lengths as the minicircles of the peridinin dinoflagellates. The fragmentation of the haptophyte-derived plastid genome K. veneficum suggests that it is likely a sign of a host-driven process shaping the plastid genomes of dinoflagellates

A framework for ensemble modelling of climate change impacts on lakes worldwide : the ISIMIP Lake Sector

Empirical evidence demonstrates that lakes and reservoirs are warming across the globe. Consequently, there is an increased need to project future changes in lake thermal structure and resulting changes in lake biogeochemistry in order to plan for the likely impacts. Previous studies of the impacts of climate change on lakes have often relied on a single model forced with limited scenario-driven projections of future climate for a relatively small number of lakes. As a result, our understanding of the effects of climate change on lakes is fragmentary, based on scattered studies using different data sources and modelling protocols, and mainly focused on individual lakes or lake regions. This has precluded identification of the main impacts of climate change on lakes at global and regional scales and has likely contributed to the lack of lake water quality considerations in policy-relevant documents, such as the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Here, we describe a simulation protocol developed by the Lake Sector of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) for simulating climate change impacts on lakes using an ensemble of lake models and climate change scenarios for ISIMIP phases 2 and 3. The protocol prescribes lake simulations driven by climate forcing from gridded observations and different Earth system models under various representative greenhouse gas concentration pathways (RCPs), all consistently bias-corrected on a 0.5 degrees x 0.5 degrees global grid. In ISIMIP phase 2, 11 lake models were forced with these data to project the thermal structure of 62 well-studied lakes where data were available for calibration under historical conditions, and using uncalibrated models for 17 500 lakes defined for all global grid cells containing lakes. In ISIMIP phase 3, this approach was expanded to consider more lakes, more models, and more processes. The ISIMIP Lake Sector is the largest international effort to project future water temperature, thermal structure, and ice phenology of lakes at local and global scales and paves the way for future simulations of the impacts of climate change on water quality and biogeochemistry in lakes.Peer reviewe