Plasma selenium levels in healthy blood bank donors in the central-eastern part of Belgium

Graphite furnace atomic absorption spectrometry, with Zeeman background correction and after improved matrix modification, was used to measure the plasma selenium content of healthy blood bank donors in the central part of Belgium.

The mean plasma selenium concentration of 80 men and 80 women was 79.7±4.4 ng/mL with a range of 55.0–117.4 ng/mL.

There was no gender difference observed. Plasma selenium level was significantly highest for the adult group, aged 45–64 years, compared to the others, except the young adults (18–24 years).

The mean plasma selenium concentration measured corresponded well with literature data for Belgium. The obtained values were found to be in the medium range, compared with recent literature values for the European countries.     

Population structuring in the monogonont rotifer Synchaeta pectinata: high genetic divergence on a small geographical scale

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The phenotype and genotype of rheumatoid arthritis in the Democratic Republic of Congo

Introduction

Little is known about rheumatoid arthritis in the black, particularly in Congolese, populations. Our objective was to describe the phenotype and genotype of rheumatoid arthritis (RA) in Congolese.

Methods

All consecutive rheumatoid arthritis (RA) patients attending Kinshasa University Hospital in a three-year time period were included. Demographics, clinical features and tobacco consumption were noted. Disease Activity Score (DAS)-28 based on the erythrocyte sedimentation rate (ESR), Health Assessment Questionnaire (HAQ), anti-citrullinated peptide antibodies (CCP) antibodies and rheumatoid factor (RF) were determined. Radiographs were scored according to Sharp-van der Heijde. On a subset of patients and controls HLA-DRB1 typing was performed.

Results

A total of 114 females and 14 males aged 51.2 ± 14.9 were included. Mean duration of symptoms was four years. Moderate tobacco consumption was reported in a minority of patients. DAS-28 at first visit was >5.1 and HAQ ≥0.5 in all patients. X-rays showed joint erosions and/or joint space narrowing, mostly of a moderate grade in 55.8% of patients. Anti-CCP and/or RF were present in 48.6% of patients with available data (n = 72) and in 3.0% of controls (n = 67). Radiographic changes and nodules were more frequent in RF or anti-CCP positive patients. One copy of the shared epitope was found in 13 patients (35.1%) and 3 controls (12.5%). Two copies were found in one patient (2.7%) and in one control (4.2%).

Conclusion

Congolese patients with RA consult long after disease onset. Despite this delay, the majority presents without major damage and is RF, anti-CCP and SE negative. We put forward the hypothesis that besides different environmental factors there is probably also a particular genetic risk profile in Congolese patients, different from the HLA-DRB1 shared epitope.     

Phylogeographical analysis of Ligia oceanica (Crustacea: Isopoda) reveals two deeply divergent mitochondrial lineages

Isopods of the species Ligia oceanica are typical inhabitants of the rocky intertidal of the northern European coastline. The aim of this study was to assess the genetic structure of this species using mitochondrial and nuclear sequence data. We analysed partial mitochondrial cytochrome c oxidase subunit I (CO1) and 16S rRNA gene sequence data of 161 specimens collected from ten sites ranging from Spain to Norway. For selected specimens, we also sequenced the hypervariable V7 expansion segment of the nuclear 18S rRNA gene as a supplementary marker. Furthermore, we studied the infection rate of all analysed specimens by the alphaproteobacterium Wolbachia. Our analyses revealed two deeply divergent mitochondrial lineages for Ligia oceanica that probably diverged in the late Pliocene to mid Pleistocene. One lineage comprised specimens from northern populations (‘lineage N’) and one primarily those from France and Spain (‘lineage S’). Distribution patterns of the haplotypes and the genetic distances between both lineages revealed two populations that diverged before the Last Glacial Maximum. Given that we found no homogenization of mitochondrial haplotypes, our present results also reject any influence of Wolbachia on the observed mtDNA variability. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 16–30.     

A phylogenetic supertree of the fowls (Galloanserae, Aves)

The fowls (Anseriformes and Galliformes) comprise one of the major lineages of birds and occupy almost all biogeographical regions of the world. The group contains the most economically important of all bird species, each with a long history of domestication, and is an ideal model for studying ecological and evolutionary patterns. Yet, despite the relatively large amount of systematic attention fowls have attracted because of their socio‐economic and biological importance, the species‐level relationships within this clade remain controversial. Here we used the supertree method matrix representation with parsimony to generate a robust estimate of species‐level relationships of fowls. The supertree represents one of the most comprehensive estimates for the group to date, including 376 species (83.2% of all species; all 162 Anseriformes and 214 Galliformes) and all but one genera. The supertree was well‐resolved (81.1%) and supported the monophyly of both Anseriformes and Galliformes. The supertree supported the partitioning of Anseriformes into the three traditional families Anhimidae, Anseranatidae, and Anatidae, although it provided relatively poor resolution within Anatidae. For Galliformes, the majority‐rule supertree was largely consistent with the hypothesis of sequential sister‐group relationships between Megapodiidae, Cracidae, and the remaining Galliformes. However, our species‐level supertree indicated that more than 30% of the polytypic genera examined were not monophyletic, suggesting that results from genus‐level comparative studies using the average of the constituent species’ traits should be interpreted with caution until analogous species‐level comparative studies are available. Poorly resolved areas of the supertree reflect gaps or outstanding conflict within the existing phylogenetic database, highlighting areas in need of more study in addition to those species not present on the tree at all due to insufficient information. Even so, our supertree will provide a valuable foundation for understanding the diverse biology of fowls in a robust phylogenetic framework.     

Analysis of methotrexate by isotachophoresis

This paper shows that the anion of methotrexate (MTX) can be readily separated and quantified by isotachophoresis. An extraction method for MTX is also presented, appropriate for isotachophoretic studies. The extraction of MTX is based on the complexation and precipitation of MTX with metal ions. The recovery of MTX from plasma is about 75%.     

Isolation and characterization of mutants corresponding to the MENA,MENB, MENC and MENE enzymatic steps of 5′‐monohydroxyphylloquinone biosynthesis in Chlamydomonas reinhardtii

Phylloquinone (PhQ), or vitamin K₁, is an essential electron carrier (A₁) in photosystem I (PSI). In the green alga Chlamydomonas reinhardtii, which is a model organism for the study of photosynthesis, a detailed characterization of the pathway is missing with only one mutant deficient for MEND having been analyzed. We took advantage of the fact that a double reduction of plastoquinone occurs in anoxia in the A₁ site in the mend mutant, interrupting photosynthetic electron transfer, to isolate four new phylloquinone‐deficient mutants impaired in MENA, MENB, MENC (PHYLLO) and MENE. Compared with the wild type and complemented strains for MENB and MENE, the four men mutants grow slowly in low light and are sensitive to high light. When grown in low light they show a reduced photosynthetic electron transfer due to a specific decrease of PSI. Upon exposure to high light for a few hours, PSI becomes almost completely inactive, which leads in turn to lack of phototrophic growth. Loss of PhQ also fully prevents reactivation of photosynthesis after dark anoxia acclimation. In silico analyses allowed us to propose a PhQ biosynthesis pathway in Chlamydomonas that involves 11 enzymatic steps from chorismate located in the chloroplast and in the peroxisome.     

Lack of isocitrate lyase in Chlamydomonas leads to changes in carbon metabolism and in the response to oxidative stress under mixotrophic growth

Isocitrate lyase is a key enzyme of the glyoxylate cycle. This cycle plays an essential role in cell growth on acetate, and is important for gluconeogenesis as it bypasses the two oxidative steps of the tricarboxylic acid (TCA) cycle in which CO₂ is evolved. In this paper, a null icl mutant of the green microalga Chlamydomonas reinhardtii is described. Our data show that isocitrate lyase is required for growth in darkness on acetate (heterotrophic conditions), as well as for efficient growth in the light when acetate is supplied (mixotrophic conditions). Under these latter conditions, reduced acetate assimilation and concomitant reduced respiration occur, and biomass composition analysis reveals an increase in total fatty acid content, including neutral lipids and free fatty acids. Quantitative proteomic analysis by ¹⁴N/¹⁵N labelling was performed, and more than 1600 proteins were identified. These analyses reveal a strong decrease in the amounts of enzymes of the glyoxylate cycle and gluconeogenesis in parallel with a shift of the TCA cycle towards amino acid synthesis, accompanied by an increase in free amino acids. The decrease of the glyoxylate cycle and gluconeogenesis, as well as the decrease in enzymes involved in β–oxidation of fatty acids in the icl mutant are probably major factors that contribute to remodelling of lipids in the icl mutant. These modifications are probably responsible for the elevation of the response to oxidative stress, with significantly augmented levels and activities of superoxide dismutase and ascorbate peroxidase, and increased resistance to paraquat.