75 research outputs found
Quantitative multilevel analysis of central metabolism in developing oilseeds of oilseed rape during in vitro culture
Seeds provide the basis for many food, feed, and fuel products. Continued increases in seed yield, composition, and quality require an improved understanding of how the developing seed converts carbon and nitrogen supplies into storage. Current knowledge of this process is often based on the premise that transcriptional regulation directly translates via enzyme concentration into flux. In an attempt to highlight metabolic control, we explore genotypic differences in carbon partitioning for in vitro cultured developing embryos of oilseed rape (Brassica napus). We determined biomass composition as well as 79 net fluxes, the levels of 77 metabolites, and 26 enzyme activities with specific focus on central metabolism in nine selected germplasm accessions. Overall, we observed a tradeoff between the biomass component fractions of lipid and starch. With increasing lipid content over the spectrum of genotypes, plastidic fatty acid synthesis and glycolytic flux increased concomitantly, while glycolytic intermediates decreased. The lipid/starch tradeoff was not reflected at the proteome level, pointing to the significance of (posttranslational) metabolic control. Enzyme activity/flux and metabolite/flux correlations suggest that plastidic pyruvate kinase exerts flux control and that the lipid/starch tradeoff is most likely mediated by allosteric feedback regulation of phosphofructokinase and ADP-glucose pyrophosphorylase. Quantitative data were also used to calculate in vivo mass action ratios, reaction equilibria, and metabolite turnover times. Compounds like cyclic 39,59-AMP and sucrose-6-phosphate were identified to potentially be involved in so far unknown mechanisms of metabolic control. This study provides a rich source of quantitative data for those studying central metabolism
Blood cytokine, chemokine and growth factor profiling in a cohort of pregnant women from tropical countries
The immune status of women changes during and after pregnancy, differs between blood compartments at delivery and is affected by environmental factors particularly in tropical areas endemic for multiple infections. We quantified the plasma concentration of a set of thirty-one TH1, TH2, TH17 and regulatory cytokines, pro-inflammatory and anti-inflammatory cytokines and chemokines, and growth factors (altogether biomarkers), in a cohort of 540 pregnant women from five malaria-endemic tropical countries. Samples were collected at recruitment (first antenatal visit), delivery (periphery, cord and placenta) and postpartum, allowing a longitudinal analysis. We found the lowest concentration of biomarkers at recruitment and the highest at postpartum, with few exceptions. Among them, IL-6, HGF and TGF-β had the highest levels at delivery, and even higher concentrations in the placenta compared to peripheral blood. Placental concentrations were generally higher than peripheral, except for eotaxin that was lower. We also compared plasma biomarker concentrations between the tropical cohort and a control group from Spain at delivery, presenting overall higher biomarker levels the tropical cohort, particularly pro-inflammatory cytokines and growth factors. Only IL-6 presented lower levels in the tropical group. Moreover, a principal component analysis of biomarker concentrations at delivery showed that women from Spain grouped more homogenously, and that IL-6 and IL-8 clustered together in the tropical cohort but not in the Spanish one. Plasma cytokine concentrations correlated with Plasmodium antibody levels at postpartum but not during pregnancy. This basal profiling of immune mediators over gestation and in different compartments at delivery is important to subsequently understand response to infections and clinical outcomes in mothers and infants in tropical areas
Microsatellite Genotyping of Plasmodium vivax Isolates from Pregnant Women in Four Malaria Endemic Countries
Plasmodium vivax is the most widely distributed human parasite
and the main cause of human malaria outside the African
continent. However, the knowledge about the genetic variability
of P. vivax is limited when compared to the information
available for P. falciparum. We present the results of a study
aimed at characterizing the genetic structure of P. vivax
populations obtained from pregnant women from different malaria
endemic settings. Between June 2008 and October 2011 nearly 2000
pregnant women were recruited during routine antenatal care at
each site and followed up until delivery. A capillary blood
sample from the study participants was collected for genotyping
at different time points. Seven P. vivax microsatellite markers
were used for genotypic characterization on a total of 229 P.
vivax isolates obtained from Brazil, Colombia, India and Papua
New Guinea. In each population, the number of alleles per locus,
the expected heterozygosity and the levels of multilocus linkage
disequilibrium were assessed. The extent of genetic
differentiation among populations was also estimated. Six
microsatellite loci on 137 P. falciparum isolates from three
countries were screened for comparison. The mean value of
expected heterozygosity per country ranged from 0.839 to 0.874
for P. vivax and from 0.578 to 0.758 for P. falciparum. P. vivax
populations were more diverse than those of P. falciparum. In
some of the studied countries, the diversity of P. vivax
population was very high compared to the respective level of
endemicity. The level of inter-population differentiation was
moderate to high in all P. vivax and P. falciparum populations
studied
Prevalence of tick-borne encephalitis virus in questing Ixodes ricinus nymphs in southern Scandinavia and the possible influence of meteorological factors
publishedVersio
Naturally Acquired Binding-Inhibitory Antibodies to Plasmodium vivax Duffy Binding Protein in Pregnant Women Are Associated with Higher Birth Weight in a Multicenter Study
A vaccine to eliminate malaria would need a multi-stage and
multi-species composition to achieve robust protection, but the
lack of knowledge about antigen targets and mechanisms of
protection precludes the development of fully efficacious
malaria vaccines, especially for Plasmodium vivax (Pv). Pregnant
women constitute a risk population who would greatly benefit
from a vaccine preventing the adverse events of Plasmodium
infection during gestation. We hypothesized that functional
immune responses against putative targets of naturally acquired
immunity to malaria and vaccine candidates will be associated
with protection against malaria infection and/or poor outcomes
during pregnancy. We measured (i) IgG responses to a large panel
of Pv and Plasmodium falciparum (Pf) antigens, (ii) the capacity
of anti-Pv ligand Duffy binding protein (PvDBP) antibodies to
inhibit binding to Duffy antigen, and (iii) cellular immune
responses to two Pv antigens, in a subset of 1,056 pregnant
women from Brazil, Colombia, Guatemala, India, and Papua New
Guinea (PNG). There were significant intraspecies and
interspecies correlations for most antibody responses (e.g.,
PfMSP119 versus PfAMA1, Spearman's rho = 0.81). Women from PNG
and Colombia had the highest levels of IgG overall.
Submicroscopic infections seemed sufficient to boost antibody
responses in Guatemala but not antigen-specific cellular
responses in PNG. Brazil had the highest percentage of Duffy
binding inhibition (p-values versus Colombia: 0.040; Guatemala:
0.047; India: 0.003, and PNG: 0.153) despite having low
anti-PvDBP IgG levels. Almost all antibodies had a positive
association with present infection, and coinfection with the
other species increased this association. Anti-PvDBP,
anti-PfMSP1, and anti-PfAMA1 IgG levels at recruitment were
positively associated with infection at delivery (p-values:
0.010, 0.003, and 0.023, respectively), suggesting that they are
markers of malaria exposure. Peripheral blood mononuclear cells
from Pv-infected women presented fewer CD8+IFN-gamma+ T cells
and secreted more G-CSF and IL-4 independently of the stimulus
used in vitro. Functional anti-PvDBP levels at recruitment had a
positive association with birth weight (difference per doubling
antibody levels: 45 g, p-value: 0.046). Thus, naturally acquired
binding-inhibitory antibodies to PvDBP might confer protection
against poor outcomes of Pv malaria in pregnancy
Development of virus-like particles with inbuilt immunostimulatory properties as vaccine candidates
The development of virus-like particle (VLP) based vaccines for human papillomavirus, hepatitis B and hepatitis E viruses represented a breakthrough in vaccine development. However, for dengue and COVID-19, technical complications, such as an incomplete understanding of the requirements for protective immunity, but also limitations in processes to manufacture VLP vaccines for enveloped viruses to large scale, have hampered VLP vaccine development. Selecting the right adjuvant is also an important consideration to ensure that a VLP vaccine induces protective antibody and T cell responses. For diseases like COVID-19 and dengue fever caused by RNA viruses that exist as families of viral variants with the potential to escape vaccine-induced immunity, the development of more efficacious vaccines is also necessary. Here, we describe the development and characterisation of novel VLP vaccine candidates using SARS-CoV-2 and dengue virus (DENV), containing the major viral structural proteins, as protypes for a novel approach to produce VLP vaccines. The VLPs were characterised by Western immunoblot, enzyme immunoassay, electron and atomic force microscopy, and in vitro and in vivo immunogenicity studies. Microscopy techniques showed proteins self-assemble to form VLPs authentic to native viruses. The inclusion of the glycolipid adjuvant, α-galactosylceramide (α-GalCer) in the vaccine formulation led to high levels of natural killer T (NKT) cell stimulation in vitro, and strong antibody and memory CD8+ T cell responses in vivo, demonstrated with SARS-CoV-2, hepatitis C virus (HCV) and DEN VLPs. This study shows our unique vaccine formulation presents a promising, and much needed, new vaccine platform in the fight against infections caused by enveloped RNA viruses
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
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