Comparative Genomics between Two Xenorhabdus bovienii Strains Highlights Differential Evolutionary Scenarios within an Entomopathogenic Bacterial Species.

Bacteria of the genus Xenorhabdus are symbionts of soil entomopathogenic nematodes of the genus Steinernema. This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Within Xenorhabdus bovienii species, the X. bovienii CS03 strain (Xb CS03) is nonvirulent when directly injected into lepidopteran insects, and displays a low virulence when associated with its Steinernema symbiont. The genome of Xb CS03 was sequenced and compared with the genome of a virulent strain, X. bovienii SS-2004 (Xb SS-2004). The genome size and content widely differed between the two strains. Indeed, Xb CS03 had a large genome containing several specific loci involved in the inhibition of competitors, including a few NRPS-PKS loci (nonribosomal peptide synthetases and polyketide synthases) producing antimicrobial molecules. Consistently, Xb CS03 had a greater antimicrobial activity than Xb SS-2004. The Xb CS03 strain contained more pseudogenes than Xb SS-2004. Decay of genes involved in the host invasion and exploitation (toxins, invasins, or extracellular enzymes) was particularly important in Xb CS03. This may provide an explanation for the nonvirulence of the strain when injected into an insect host. We suggest that Xb CS03 and Xb SS-2004 followed divergent evolutionary scenarios to cope with their peculiar life cycle. The fitness strategy of Xb CS03 would involve competitor inhibition, whereas Xb SS-2004 would quickly and efficiently kill the insect host. Hence, Xenorhabdus strains would have widely divergent host exploitation strategies, which impact their genome structure.

Pre- and postnatal depression and coping: a comparative approach.

BACKGROUND: The assessment of perinatal depressions and coping style. METHODS: With depression scales (EPDS, GHQ.12) and Carver's BriefCope, the authors compared the prevalence rates of pre and postnatal depression in a cohort of 277 French women. RESULTS: Their work revealed very high levels of prenatal depression (almost 20%) and less important but nonetheless sizeable rates (11%) of postnatal depression, making such perinatal depressions a major public health concern. The coping styles proposed in Carver's public health BriefCope questionnaire make it possible to significantly differentiate during these two periods between depressive women and their non-depressed counterparts. CONCLUSIONS: This enables us to underline factors of risk and protection suggesting the importance of setting up compensatory and preventive systems and evaluating their pertinence in the framework of future research.

Attenuated virulence and genomic reductive evolution in the entomopathogenic bacterial symbiont species, Xenorhabdus poinarii.

Bacteria of the genus Xenorhabdus are symbionts of soil entomopathogenic nematodes of the genus Steinernema. This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Unlike other Xenorhabdus species, Xenorhabdus poinarii is avirulent when injected into insects in the absence of its nematode host. We sequenced the genome of the X. poinarii strain G6 and the closely related but virulent X. doucetiae strain FRM16. G6 had a smaller genome (500-700 kb smaller) than virulent Xenorhabdus strains and lacked genes encoding potential virulence factors (hemolysins, type 5 secretion systems, enzymes involved in the synthesis of secondary metabolites, and toxin-antitoxin systems). The genomes of all the X. poinarii strains analyzed here had a similar small size. We did not observe the accumulation of pseudogenes, insertion sequences or decrease in coding density usually seen as a sign of genomic erosion driven by genetic drift in host-adapted bacteria. Instead, genome reduction of X. poinarii seems to have been mediated by the excision of genomic blocks from the flexible genome, as reported for the genomes of attenuated free pathogenic bacteria and some facultative mutualistic bacteria growing exclusively within hosts. This evolutionary pathway probably reflects the adaptation of X. poinarii to specific host.

Genome Sequence of Halomonas sp. Strain A3H3, Isolated from Arsenic-Rich Marine Sediments.

We report the genome sequence of Halomonas sp. strain A3H3, a bacterium with a high tolerance to arsenite, isolated from multicontaminated sediments of the l'Estaque harbor in Marseille, France. The genome is composed of a 5,489,893-bp chromosome and a 157,085-bp plasmid.

Quality of life, postnatal depression and baby gender.

AIMS AND OBJECTIVE: To study the impact of postnatal depression on the quality of life of young French mothers and to evaluate if the gender of their child influences this. BACKGROUND: Postnatal depression (PND) constitutes a major public health problem considering its high prevalence and consequences upon quality of life and parental skills. DESIGN: This research is a cross-sectional study during the postnatal period. METHODS: This study was carried out during a two-month period. Data were collected by interview and questionnaires. The authors compared the prevalence rate of PND and life quality in a cohort of 181 women and measured the short-term impact of the child's birth. RESULTS: Postnatal depression strongly negatively influences all dimensions of life quality explored through the SF36, e.g. physical functioning (PF), physical Role (RP), bodily pain (BP), mental health (MH), emotional role (RE), social functioning (SF), vitality (VT), general health (GH), standardized physical component (PCS) and standardized mental component (MCS). The baby's gender (having a boy) also significantly reduces quality of life, irrespective of depressive state. There is a relationship between baby gender and PND. CONCLUSION: This research is the first to show that the birth of a boy reduces several dimensions of the mothers' quality of life. RELEVANCE TO CLINICAL PRACTICE: The importance of the impairment of quality of life in case of PND, as well as its effects on mother-child interaction, could justify prevention programs and early psychotherapeutic care. Further research needs to explore the effectiveness of programmes targeting the construction of parenting skills as a preventative measure against PND, especially for parents of boys.

Genetic polymorphisms and lipoprotein responses to diets.

While human diets have markedly evolved since their origin, the human genome has only marginally changed. Nevertheless, polymorphisms of common genes are widespread. It has been substantiated that most major diseases (including cardiovascular disease, diabetes, obesity and cancers) result from the interaction between genetic susceptibility and environmental factors, including diet. In the field of lipoprotein metabolism and cardiovascular disease several gene polymorphisms for key proteins, such as apoproteins (apo) E, B, A-IV and C-III, LDL receptor, microsomal transfer protein (MTP), fatty acid-binding protein (FABP), cholesteryl ester transfer protein (CETP), lipoprotein lipase and hepatic lipase, have been identified and linked to variable responses to diets. We are carrying out an intervention study (RIVAGE) in Marseille dedicated to investigating the interactions between diets (Mediterranean or low-fat types v. standard Western type), risk factors for cardiovascular disease and gene polymorphisms in about 300 patients randomized into two groups over periods of 3 and 12 months. Some data obtained in about 100 patients after 3 months of dietary change are available. Among single nucleotide polymorphisms (SNP) already studied (apoE (epsilon2, epsilon3, epsilon4), apoB (-516C/T), apoC-III (SstI), apoA-IV (Ser347Thr), MTP (-493G/T), intestinal FABP (Ala54Thr), CETP (TaqIB) and hepatic lipase (-480C/T)), some SNP showed interactions with diets in relation to changes in particular variables after 3 months on the dietary regimens. This was the case for apoE and LDL-cholesterol and triacylglycerols, apoA-IV and LDL-cholesterol, MTP and LDL-cholesterol, intestinal FABP and triacylglycerols. These data provide evidence of the interaction between some SNP and the metabolic response to diets.

Nelfinavir induces necrosis of 3T3F44-2A adipocytes by oxidative stress.

Protease inhibitor treatment strongly diminishes mortality in HIV-infected patients. This treatment has also been associated with lipodystrophy and has been shown to alter adipocyte differentiation. The protease inhibitor nelfinavir has been indirectly implicated in the appearance and development of lipodystrophic syndrome, as well as in adipocyte cell death. The aim of this study was to evaluate the effects of nelfinavir on the 3T3-F442A adipocyte cell line. Nelfinavir (30 microM) induced cell death of 3T3-F442A adipocytes by a necrotic process that was not mediated by TNF-alpha. Treatment of cells with this protease inhibitor led to a significant increase in expression of the heme oxygenase-1 gene that could be reduced by 100 microM of the antioxidant ascorbate. Moreover, ascorbate had a protective effect on nelfinavir-induced necrosis, decreasing the percentage of necrotic cells by 70%. Our results show that nelfinavir induces necrosis of adipocytes mediated by a cellular increase of reactive oxygen species. This deleterious effect could be counterbalanced by ascorbate.

Dietary fibre intake and clinical indices in the French Supplementation en Vitamines et Minéraux AntioXydants (SU.VI.MAX) adult cohort.

The aim of our study was to investigate the relationship between dietary fibre intake and some clinical indices, blood biochemical variables and the incidence of cardiovascular disease and cancers in France, taking advantage of an ongoing cohort, the Supplementation en Vitamines et Minéraux AntioXydants (SU.VI.MAX) intervention study. This preliminary report provides data on dietary fibre intake in this French adult population group of 4080 subjects (2168 men and 1912 women) aged 45-65 years at inclusion. The data obtained for fibre intake indicate that most men and women have low to moderate intakes of total dietary fibre (mean 21.0 and 17.1 g/d respectively), with only 21 % of the men and 7 % of the women having total dietary fibre intakes at the recommended level (i.e. > 25 g/d) and soluble fibre accounting for 19 % of the total dietary fibre intake for both genders. The main food sources of dietary fibre are cereals (30-35 % total), vegetables (20-24 % total) and fruit (19-22 % total). No marked regional differences were observed within France. The highest dietary fibre intakes have been found to be associated with a lower BMI, blood systolic pressure, plasma triacylglycerols and plasma glucose in men and lower BMI in women. Overall, these data support the concept of a beneficial effect of a high dietary fibre intake on cardiovascular disease risk.