1,761 research outputs found
Molecular Epidemiology of Ascariasis: A Global Perspective on the Transmission Dynamics of Ascaris in People and Pigs
Background
The roundworm Ascaris lumbricoides infects 0.8 billion people worldwide, and Ascaris suum infects innumerable pigs across the globe. The extent of natural cross-transmission of Ascaris between pig and human hosts in different geographical settings is unknown, warranting investigation.
Methods
Adult Ascaris organisms were obtained from humans and pigs in Europe, Africa, Asia, and Latin America. Barcodes were assigned to 536 parasites on the basis of sequence analysis of the mitochondrial cytochrome c oxidase I gene. Genotyping of 410 worms was also conducted using a panel of microsatellite markers. Phylogenetic, population genetic, and Bayesian assignment methods were used for analysis.
Results
There was marked genetic segregation between worms originating from human hosts and those originating from pig hosts. However, human Ascaris infections in Europe were of pig origin, and there was evidence of cross-transmission between humans and pigs in Africa. Significant genetic differentiation exists between parasite populations from different countries, villages, and hosts.
Conclusions
In conducting an analysis of variation within Ascaris populations from pig and human hosts across the globe, we demonstrate that cross-transmission takes place in developing and developed countries, contingent upon epidemiological potential and local phylogeography. Our results provide novel insights into the transmission dynamics and speciation of Ascaris worms from humans and pigs that are of importance for control program
Site of action of a halogenated 4-hydroxypyridine on ferredoxin-catalysed cyclic photophosphorylation
AbstractTetrabromo-4-hydroxypyridine (J820) inhibited ferredoxin-catalysed cyclic photophosphorylation at micromolar concentrations but did not inhibit or uncouple the AQS-catalysed system. At 2 μM it did not abolish the slow phase of the electrochromic shift or affect the turnover of cytochromes b-563 and f. At higher concentrations (10 μM) it decreased the rate of re-reduction of cytochrome f, whilst inhibiting the reduction of cytochrome b-563. It is concluded that tetrabromo-4-hydroxpyridine does not bind to the quinone reduction site of the cytochrome bf complex, but inhibits the putative ferredoxin-plastoquinone reductase
An investigation into the feasibility of myoglobin-based single-electron transistors
Myoglobin single-electron transistors were investigated using nanometer- gap
platinum electrodes fabricated by electromigration at cryogenic temperatures.
Apomyoglobin (myoglobin without heme group) was used as a reference. The
results suggest single electron transport is mediated by resonant tunneling
with the electronic and vibrational levels of the heme group in a single
protein. They also represent a proof-of-principle that proteins with redox
centers across nanometer-gap electrodes can be utilized to fabricate
single-electron transistors. The protein orientation and conformation may
significantly affect the conductance of these devices. Future improvements in
device reproducibility and yield will require control of these factors
Force and energy dissipation variations in non-contact atomic force spectroscopy on composite carbon nanotube systems
UHV dynamic force and energy dissipation spectroscopy in non-contact atomic
force microscopy were used to probe specific interactions with composite
systems formed by encapsulating inorganic compounds inside single-walled carbon
nanotubes. It is found that forces due to nano-scale van der Waals interaction
can be made to decrease by combining an Ag core and a carbon nanotube shell in
the Ag@SWNT system. This specific behaviour was attributed to a significantly
different effective dielectric function compared to the individual
constituents, evaluated using a simple core-shell optical model. Energy
dissipation measurements showed that by filling dissipation increases,
explained here by softening of C-C bonds resulting in a more deformable
nanotube cage. Thus, filled and unfilled nanotubes can be discriminated based
on force and dissipation measurements. These findings have two different
implications for potential applications: tuning the effective optical
properties and tuning the interaction force for molecular absorption by
appropriately choosing the filling with respect to the nanotube.Comment: 22 pages, 6 figure
Online, social media and mobile technologies for psychosis treatment: a systematic review on novel user-led interventions
Internet and mobile-based interventions provide a unique opportunity to deliver cost-effective, accessible, time-unlimited support to people with psychosis. The aims of this study were to systematically compile and analyze the evidence on the acceptability, feasibility, safety and benefits of online and mobile-based interventio is
for psychosis. Methods: Systematic review of peer-reviewed studies examining the usability, acceptability, feasibility, safety or efficacy of user-led, Internet or mobile-based interventions, with at least 80% of participants diagnosed with schizophrenia-spectrum disorders. Results: Of 38 potentially relevant articles, 12 were eligible for inclusion. Interventions included web-based psycho-education; web-based psycho-education plus moderated forums for patients and supporters; integrated web-based therapy, social networking and peer and expert moderation; web-based CBT; personalized advice
based on clinical monitoring; and text messaging interventions. Results showed that 74–86% of patients used the web-based interventions efficiently, 75–92% perceived them as positive and useful, and 70–86% completed or were engaged with the interventions over the follow-up. Preliminary evidence indicated that online and mobile-based interventions show promise in improving positive psychotic symptoms, hospital admissions, socialization, social connectedness, depression and medication adherence.
Conclusions: Internet and mobile-based interventions for psychosis seem to be acceptable and feasible and have the potential to improve clinical and social outcomes. The heterogeneity, poor quality and early state of current research precludes any definite conclusions. Future research should investigate the efficacy of online and mobile
interventions through controlled, well-powered studies, which investigate intervention and patient factors associated with take-up and intervention effects
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Comprehensive Immune Monitoring of Clinical Trials to Advance Human Immunotherapy.
The success of immunotherapy has led to a myriad of clinical trials accompanied by efforts to gain mechanistic insight and identify predictive signatures for personalization. However, many immune monitoring technologies face investigator bias, missing unanticipated cellular responses in limited clinical material. We present here a mass cytometry (CyTOF) workflow for standardized, systems-level biomarker discovery in immunotherapy trials. To broadly enumerate immune cell identity and activity, we established and extensively assessed a reference panel of 33 antibodies to cover major cell subsets, simultaneously quantifying activation and immune checkpoint molecules in a single assay. This assay enumerates ≥98% of peripheral immune cells with ≥4 positively identifying antigens. Robustness and reproducibility are demonstrated on multiple samples types, across two research centers and by orthogonal measurements. Using automated analysis, we identify stratifying immune signatures in bone marrow transplantation-associated graft-versus-host disease. Together, this validated workflow ensures comprehensive immunophenotypic analysis and data comparability and will accelerate biomarker discovery
Teleost and elasmobranch eye lenses as a target for life-history stable isotope analyses
Incrementally grown, metabolically inert tissues such as fish otoliths provide biochemical records that can used to infer behavior and physiology throughout the lifetime of the individual. Organic tissues are particularly useful as the stable isotope composition of the organic component can provide information about diet, trophic level and location. Unfortunately, inert, incrementally grown organic tissues are relatively uncommon. The vertebrate eye lens, however, is formed via sequential deposition of protein-filled fiber cells, which are subsequently metabolically inert. Lenses therefore have the potential to serve as biochemical data recorders capturing life-long variations in dietary and spatial ecology. Here we review the state of knowledge regarding the structure and formation of fish eye lenses in the context of using lens tissue for retrospective isotopic analysis. We discuss the relationship between eye lens diameter and body size, describe the successful recovery of expected isotopic gradients throughout ontogeny and between species, and quantify the isotopic offset between lens protein and white muscle tissue. We show that fish eye lens protein is an attractive host for recovery of stable isotope life histories, particularly for juvenile life stages, and especially in elasmobranchs lacking otoliths, but interpretation of lens-based records is complicated by species-specific uncertainties associated with lens growth rates
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