Epidémiologie moléculaire du virus de l'hépatite B chez 1276 femmes enceintes au Cameroun

POITIERS-BU Médecine pharmacie (861942103) / SudocSudocFranceF

Regulation of shoot branching by light competition in WOSR: how to disentangle the respective effects of light intensity and light spectrum (Red:Far-red ratio) in dense crops?

International audienc

Validated Method for Strigolactone Quantification by Ultra High-Performance Liquid Chromatography - Electrospray Ionisation Tandem Mass Spectrometry Using Novel Deuterium Labelled Standards

International audienceIntroduction =Strigolactones (SLs) are important plant hormones. They are difficult to analyse because they occur in very small concentrations especially in comparison with other plant hormones and other substances can interfere with their detection.Objective =To develop a procedure for the extraction, purification and quantification of SLs from plant roots.Methodology =Samples were prepared by extraction of plant root tissues with ethyl acetate. Then the extracts were further purified with silica column chromatography. The natural SLs in the final extracts were quantified using novel deuterium labelled SLs. The results of the methodology were compared with those of the procedure of Yoneyama and coworkers.Results =This procedure required about 1‐g root samples to detect and quantify simultaneously the SLs (orobanchyl acetate and fabacyl acetate) concentration with high reliability.Conclusion =A method was developed for determining endogenous fabacyl acetate and orobanchyl acetate in plant tissue based on novel deuterium labelled standards. A method of orobanchol quantification using a synthetic SL GR24 as internal standard was proposed

High endemicity and low molecular diversity of hepatitis B virus infections in pregnant women in a rural district of North Cameroon.

BACKGROUND: A program, supported by the GEMHEP (Groupe d'étude Moléculaire des Hépatites), was established in 2007 in the sanitary district of Tokombéré, to prevent perinatal transmission of hepatitis B virus (HBV). It comprises screening for HBV surface antigen (HBsAg) in all pregnant women and vaccinating the newborn if tests are positive. METHODS/PRINCIPAL FINDINGS: 1276 women were enrolled in the study after providing informed consent. Demographic data and blood samples were available for 1267 of the enrolled patients. HBsAg was determined locally using a rapid test (Vikia HBsAg, Biomerieux). Tests for HBV and HDV virological markers (HBeAg, anti-HDV antibodies (Ab), HBV-DNA, HDV-RNA, HBV and HDV genotypes) were performed on the confirmed HBsAg-positive samples in the virology unit of the Angers University Hospital (France). HBsAg was found in 259 of the 1267 pregnant women (20.4%) between January 2009 and April 2010, of whom 59 were HBeAg-positive (22.7%) with high levels of HBV-DNA. Anti-HDV Ab were found in 19 (7.3%) of the HBsAg-positive women. The prevalence rates of HBsAg and HDV were not age-dependent whereas HBeAg carriers were statistically younger than non carriers. Basal core promoter (BCP) and precore (PC) mutations and genotypes were determined by sequencing. Of 120 amplified sequences, 119 belonged to HBV genotype E (HBV/E) and the 9 HDV strains belonged to HDV clade 1. In the PC region, 83/228 patients (36.4%) harbored a G1896A mutant or mixed phenotype virus. In the BCP region, the double mutation A1762T/G1764A and the G1757A substitution were detected respectively in 26/228 patients (11.4%) and 189/228 patients (82.8%). CONCLUSIONS: Our results confirm the high prevalence and low molecular diversity of HBV in Far Northern Cameroon; more than 20% of the infected women were highly viremic, suggesting a high rate of HBV perinatal transmission and supporting the WHO recommendation to vaccinate at birth against hepatitis B

Plots of Log IU/mL HBV-DNA according to the HBe status.

<p>Quantification of HBV DNA using the Abbott Real Time HBV PCR: the median of the log IU/mL HBV viral load (solid black bar in the figure) was significantly higher in HBeAg-positive pregnant women than HBeAg-negative ones (8.33 log IU/mL versus 2.05 log IU/mL respectively).</p

New strigolactone analogs as plant hormones with low activities in the rhizosphere

Strigolactones (SLs) are known not only as plant hormones, but also as rhizosphere signals for establishing symbiotic and parasitic interactions. The design of new specific SL analogs is a challenging goal in understanding the basic plant biology and is also useful to control plant architectures without favoring the development of parasitic plants. Two different molecules (23 (3′-methyl-GR24), 31 (thia-3′-methyl-debranone-like molecule)) already described, and a new one (AR36), for which the synthesis is presented, are biologically compared with the well-known GR24 and the recently identified CISA-1. These different structures emphasize the wide range of parts attached to the D-ring for the bioactivity as a plant hormone. These new compounds possess a common dimethylbutenolide motif but their structure varies in the ABC part of the molecules: 23 has the same ABC part as GR24, while 31 and AR36 carry, respectively, an aromatic ring and an acyclic carbon chain. Detailed information is given for the bioactivity of such derivatives in strigolactone synthesis or in perception mutant plants (pea rms1 and rms4, Arabidopsis max2 and, max4) for different hormonal functions along with their action in the rhizosphere on arbuscular mycorrhizal hyphal growth and parasitic weed germination

HBV DNA quantification.

<p>Serum HBV DNA levels were quantified in 72 consecutive samples with the Abbott Real Time HBV PCR (threshold at 1.7 log IU/mL). HBV target was not detected in 21 patients; viral load was detected in 51 patients, 16 of whom had a viral load greater than 7 log IU/mL.</p

Results of the polymerase gene HBV amplification.

<p>The HBV DNA was amplified using a qualitative PCR with a threshold at 3 log UI/mL and the results were correlated with the HBeAg profile in HBsAg-positive pregnant women.</p