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The application of bacterial bio-inputs is a very attractive alternative to the use of mineral fertilisers. In ploughed soils including a crop rotation pea, we observed an enrichment of bacterial communities with Sphingomonas (S.) sediminicola. Inoculation experiments, cytological studies, and de novo sequencing were used to investigate the beneficial role of S. sediminicola in pea. S. sediminicola is able to colonise pea plants and establish a symbiotic association that promotes plant biomass production. Sequencing of the S. sediminicola genome revealed the existence of genes involved in secretion systems, Nod factor synthesis, and nitrogenase activity. Light and electron microscopic observations allowed us to refine the different steps involved in the establishment of the symbiotic association, including the formation of infection threads, the entry of the bacteria into the root cells, and the development of differentiated bacteroids in root nodules. These results, together with phylogenetic analysis, demonstrated that S. sediminicola is a non-rhizobia that has the potential to develop a beneficial symbiotic association with a legume. Such a symbiotic association could be a promising alternative for the development of more sustainable agricultural practices, especially under reduced N fertilisation conditions.

To monitor the prevalence of hepatitis B and hepatitis C a cross-sectional survey was conducted in 2004 among French metropolitan residents. A complex sampling design was used to enroll 14,416 adult participants aged 18-80 years. Data collected included demographic and social characteristics and risk factors. Sera were tested for anti-HCV, HCV-RNA, anti-HBc and HBsAg. Data were analyzed with SUDAAN software to provide weighted estimates for the French metropolitan resident population. The overall anti-HCV prevalence was 0.84% (95% CI: 0.65-1.10). Among anti-HCV positive individuals, 57.4% (95% CI: 43.2-70.5) knew their status. Factors associated independently with positive anti-HCV were drug use (intravenous and nasal), blood transfusion before 1992, a history of tattoos, low socioeconomic status, being born in a country where anti-HCV prevalence2.5%, and age29 years. The overall anti-HBc prevalence was 7.3% (95%: 6.5-8.2). Independent risk factors for anti-HBc were intravenous drug use, being a man who has sex with men, low socioeconomic status, a stay in a psychiatric facility or facility for the mentally disabled,12 years of education, being born in a country where HBsAg prevalence2%, age29 and male sex. The HCV RNA and HBsAg prevalence were 0.53% (95% CI: 0.40-0.70) and 0.65% (95% CI: 0.45-0.93), respectively. Among HBsAg positive individuals, 44.8% (95% CI: 22.8-69.1) knew their status. Anti-HCV prevalence was close to the 1990s estimates whereas HBsAg prevalence estimate was greater than expected. Screening of hepatitis B and C should be strengthened and should account for social vulnerability.