Multi-residue analysis of eight anticoagulant rodenticides in animal plasma and liver using liquid chromatography combined with heated electrospray ionization tandem mass spectrometry

The determination of C-terminal peptide sequence is critical since the C-terminal peptide contains biologically relevant information and often undergoes post-translational processing. Another important application is in estimating purity of the biopharmaceuticals, especially for determining the presence of ragged processed ends and for N-terminally blocked polypeptides and proteins. In this paper, different isotope coding strategies in combination with reversed phase chromatography (RPC) coupled with electrospray ionization-mass spectrometry (ESI-MS) were evaluated to detect the C-terminal peptide from proteolytic digests. These were (i) O18 (ii) acylation and (iii) esterification based isotope coding strategies. Using reversed phase chromatography, the C-terminal peptide was resolved from other internal peptides. The isotope coding approaches specifically rendered a characteristic MS signature to the C-terminal peptide, thereby facilitating its detection. The unique MS signature, along with accurate mass data for the C-terminal peptide was found to be sufficient for its detection and identification. The advantages and limitations of the three approaches will be discussed.     

Brain responses to violet, blue, and green monochromatic light exposures in humans: prominent role of blue light and the brainstem

Background

Relatively long duration retinal light exposure elicits nonvisual responses in humans, including modulation of alertness and cognition. These responses are thought to be mediated in part by melanopsin-expressing retinal ganglion cells which are more sensitive to blue light than violet or green light. The contribution of the melanopsin system and the brain mechanisms involved in the establishment of such responses to light remain to be established.

Methodology/Principal Findings

We exposed 15 participants to short duration (50 s) monochromatic violet (430 nm), blue (473 nm), and green (527 nm) light exposures of equal photon flux (10¹³ph/cm²/s) while they were performing a working memory task in fMRI. At light onset, blue light, as compared to green light, increased activity in the left hippocampus, left thalamus, and right amygdala. During the task, blue light, as compared to violet light, increased activity in the left middle frontal gyrus, left thalamus and a bilateral area of the brainstem consistent with activation of the locus coeruleus.

Conclusion/Significance

These results support a prominent contribution of melanopsin-expressing retinal ganglion cells to brain responses to light within the very first seconds of an exposure. The results also demonstrate the implication of the brainstem in mediating these responses in humans and speak for a broad involvement of light in the regulation of brain function.     

Short-term long chain omega3 diet protects from neuroinflammatory processes and memory impairment in aged mice

Regular consumption of food enriched in omega3 polyunsaturated fatty acids (ω3 PUFAs) has been shown to reduce risk of cognitive decline in elderly, and possibly development of Alzheimer's disease. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are the most likely active components of ω3-rich PUFAs diets in the brain. We therefore hypothesized that exposing mice to a DHA and EPA enriched diet may reduce neuroinflammation and protect against memory impairment in aged mice. For this purpose, mice were exposed to a control diet throughout life and were further submitted to a diet enriched in EPA and DHA during 2 additional months. Cytokine expression together with a thorough analysis of astrocytes morphology assessed by a 3D reconstruction was measured in the hippocampus of young (3-month-old) and aged (22-month-old) mice. In addition, the effects of EPA and DHA on spatial memory and associated Fos activation in the hippocampus were assessed. We showed that a 2-month EPA/DHA treatment increased these long-chain ω3 PUFAs in the brain, prevented cytokines expression and astrocytes morphology changes in the hippocampus and restored spatial memory deficits and Fos-associated activation in the hippocampus of aged mice. Collectively, these data indicated that diet-induced accumulation of EPA and DHA in the brain protects against neuroinflammation and cognitive impairment linked to aging, further reinforcing the idea that increased EPA and DHA intake may provide protection to the brain of aged subjects.     

Identification and quantification of concentration-dependent biomarkers in MCF-7/BOS cells exposed to 17β-estradiol by 2-D DIGE and label-free proteomics

This paper reports the identification of biomarkers resulting from the exposure of MCF-7/BOS cells to 17β-estradiol (E(2)). The biomarkers were identified using 2 independent and complementary techniques, 2-D DIGE/MALDI-TOF peptide mass fingerprint, and 2-D UPLC-ESI MS/MS. They were identified from the cytosolic fractions of cells treated for 24h with mitogenic concentrations of 1, 30 and 500 pM of 17β-estradiol. Five biomarkers were up-regulated proteins, namely HSP 74, EF2, FKBP4, EF1 and GDIB and one was a down-regulated protein, namely K2C8. Three of these proteins, EF2, FKBP4 and K2C8 are implicated in a network centered on the estrogen receptors ESR1 and ESR2 as well as on AKT1. After the discovery phase, three biomarkers were selected to test the presence of estrogens using selected reaction monitoring (SRM). They were monitored using SRM after incubation of MCF-7/BOS in the presence of E(2) for confirmation or selected xenoestrogens. Daidzein, coumestrol and enterolactone induced an up-regulation of EF2 and FKPB4 proteins, while tamoxifen and resveratrol induced a down-regulation. The exposure of all phytoestrogens induced the down-regulation of K2C8. These markers form a preliminary molecular signature that can be used when testing the estrogenic activity of xenobiotics, either pure or in mixtures.     

Characterization of natural hybrids of Saccharomyces cerevisiae and Saccharomyces bayanus var. uvarum

Nine yeast strains were isolated from spontaneous fermentations in the Alsace area of France, during the 1997, 1998 and 1999 grape harvests. Strains were characterized by pulsed-field gel electrophoresis, PCR-restriction fragment length polymorphism (RFLP) of the MET2 gene, delta-PCR, and microsatellite patterns. Karyotypes and MET2 fragments of the nine strains corresponded to mixed chromosomal bands and restriction patterns for both Saccharomyces cerevisiae and Saccharomyces bayanus var. uvarum. They also responded positively to amplification with microsatellite primers specific to both species and were demonstrated to be diploid. However, meiosis led to absolute nonviability of their spores on complete medium. All the results demonstrated that the nine yeast strains isolated were S. cerevisiaexS. bayanus var. uvarum diploid hybrids. Moreover, microsatellite DNA analysis identified strains isolated in the same cellar as potential parents belonging to S. bayanus var. uvarum and S. cerevisiae.     

Irreversible inhibition of aldolase by a phosphorylated alpha-dicarbonyl compound

The preparation of a phosphorylated alpha-dicarbonyl compound designed to specifically react with arginine residues of enzymes accepting phosphorylated compounds as effectors is reported, and shown to inhibit rabbit muscle aldolase in a time-dependent and irreversible manner. This irreversible inhibition occured in a buffer devoid of borate ions, suggesting that the presence of the phosphate moiety contributes in the stabilization of the adduct formed with arginine residues. Under the same conditions, the metalloenzyme iron superoxide dismutase, in which an arginine is known to be critical for the catalytic function, is not significantly inhibited.     

Genetic snapshots of the Rhizobium species NGR234 genome

Background  

In nitrate-poor soils, many leguminous plants form nitrogen-fixing symbioses with members of the bacterial family Rhizobiaceae. We selected Rhizobium sp. NGR234 for its exceptionally broad host range, which includes more than 112 genera of legumes. Unlike the genome of Bradyrhizobium japonicum, which is composed of a single 8.7 Mb chromosome, that of NGR234 is partitioned into three replicons: a chromosome of about 3.5 Mb, a megaplasmid of more than 2 Mb (pNGR234b) and pNGR234a, a 536,165 bp plasmid that carries most of the genes required for symbioses with legumes. Symbiotic loci represent only a small portion of all the genes coded by rhizobial genomes, however. To rapidly characterize the two largest replicons of NGR234, the genome of strain ANU265 (a derivative strain cured of pNGR234a) was analyzed by shotgun sequencing.     

Temporal Trends in Treatment Outcomes for HIV-1 and HIV-2-Infected Adults Enrolled in C?te d'Ivoire's National Antiretroviral Therapy Program

Background

In Côte d''Ivoire during 2004–2007, numbers of ART enrollees increased from <5,000 to 36,943. Trends in nationally representative ART program outcomes have not yet been reported.

Methodology/Principal Findings

We conducted a retrospective chart review to assess trends in patient characteristics and attrition [death or loss to follow-up (LTFU)] over time, among a nationally representative sample of 3,682 adults (≥15 years) initiating ART during 2004–2007 at 34 health facilities. Among ART enrollees during 2004–2007, median age was 36, the proportion female was 67%, the proportion HIV-2-infected or dually HIV-1&2 reactive was 5%, and median baseline CD4⁺ T-cell (CD4) count was 135 cells/µL. Comparing cohorts initiating ART in 2004 with cohorts initiating ART in 2007, median baseline weight declined from 55 kg to 52 kg (p = 0.008) and the proportion weighing <45 kg increased from 17% to 22% (p = 0.014). During 2004–2007, pharmacy-based estimates of the percentage of new ART enrollees ≥95% adherent to ART declined from 74% to 60% (p = 0.026), and twelve-month retention declined from 86% to 69%, due to increases in 12-month mortality from 2%–4% and LTFU from 12%–28%. In univariate analysis, year of ART initiation was associated with increasing rates of both LTFU and mortality. Controlling for baseline CD4, weight, adherence, and other risk factors, year of ART initiation was still strongly associated with LTFU but not mortality. In multivariate analysis, weight <45 kg and adherence <95% remained strong predictors of LTFU and mortality.

Conclusions

During 2004–2007, increasing prevalence among ART enrollees of measured mortality risk factors, including weight <45 kg and ART adherence <95%, might explain increases in mortality over time. However, the association between later calendar year and increasing LTFU is not explained by risk factors evaluated in this analysis. Undocumented transfers, political instability, and patient dissatisfaction with crowded facilities might explain increasing LTFU.