Engineering modular and orthogonal genetic logic gates for robust digital-like synthetic biology

Modular and orthogonal genetic logic gates are essential for building robust biologically based digital devices to customize cell signalling in synthetic biology. Here we constructed an orthogonal AND gate in Escherichia coli using a novel hetero-regulation module from Pseudomonas syringae. The device comprises two co-activating genes hrpR and hrpS controlled by separate promoter inputs, and a σ54-dependent hrpL promoter driving the output. The hrpL promoter is activated only when both genes are expressed, generating digital-like AND integration behaviour. The AND gate is demonstrated to be modular by applying new regulated promoters to the inputs, and connecting the output to a NOT gate module to produce a combinatorial NAND gate. The circuits were assembled using a parts-based engineering approach of quantitative characterization, modelling, followed by construction and testing. The results show that new genetic logic devices can be engineered predictably from novel native orthogonal biological control elements using quantitatively in-context characterized parts

Complete Genomic Characterization of a Pathogenic A.II Strain of Francisella tularensis Subspecies tularensis

Francisella tularensis is the causative agent of tularemia, which is a highly lethal disease from nature and potentially from a biological weapon. This species contains four recognized subspecies including the North American endemic F. tularensis subsp. tularensis (type A), whose genetic diversity is correlated with its geographic distribution including a major population subdivision referred to as A.I and A.II. The biological significance of the A.I – A.II genetic differentiation is unknown, though there are suggestive ecological and epidemiological correlations. In order to understand the differentiation at the genomic level, we have determined the complete sequence of an A.II strain (WY96-3418) and compared it to the genome of Schu S4 from the A.I population. We find that this A.II genome is 1,898,476 bp in size with 1,820 genes, 1,303 of which code for proteins. While extensive genomic variation exists between “WY96” and Schu S4, there is only one whole gene difference. This one gene difference is a hypothetical protein of unknown function. In contrast, there are numerous SNPs (3,367), small indels (1,015), IS element differences (7) and large chromosomal rearrangements (31), including both inversions and translocations. The rearrangement borders are frequently associated with IS elements, which would facilitate intragenomic recombination events. The pathogenicity island duplicated regions (DR1 and DR2) are essentially identical in WY96 but vary relative to Schu S4 at 60 nucleotide positions. Other potential virulence-associated genes (231) varied at 559 nucleotide positions, including 357 non-synonymous changes. Molecular clock estimates for the divergence time between A.I and A.II genomes for different chromosomal regions ranged from 866 to 2131 years before present. This paper is the first complete genomic characterization of a member of the A.II clade of Francisella tularensis subsp. tularensis

Liver transplantation for patients with human immunodeficiency virus and hepatitis C virus coinfection with special reference to hemophiliac recipients in Japan.

Liver transplantation for patients with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) remains challenging. The advent of highly active antiretroviral therapy (HAART) for HIV has reduced mortality from opportunistic infection related to acquired immunodeficiency syndrome dramatically, while about 50% of patients die of end-stage liver cirrhosis resulting from HCV. In Japan, liver cirrhosis frequently develops after HCV-HIV coinfection resulting from previously transfused infected blood products for hemophilia. The problems of liver transplantation for those patients arise from the need to control calcineurin inhibitor with HAART drugs, the difficulty of using interferon after liver transplantation with HAART, and the need to control intraoperative coagulopathy associated with hemophilia. We review published reports of liver transplantation for these patients in the updated world literature

Infections de prothèse ostéo-articulaire traitées par débridement : facteurs prédictifs d’échec [Predictors of failure for prosthetic joint infections treated with debridement]

International audienceOBJECTIVE: Prosthetic joint infections (PJI) may be cured in selected patients with debridement and prosthesis retention. We aimed to identify predictors of failure to better target patients most likely to benefit from this conservative strategy. METHODS: Observational study of patients presenting with PJI initially treated at our hospital with debridement between 2008 and 2011, with\textgreater6 months of post-treatment follow-up. RESULTS: Sixty consecutive patients presenting with PJI (hip, n=34; knee, n=26) fulfilled the inclusion criteria. Failures (n=20, 33%), predefined as persistence of PJI signs or relapses, were managed with additional surgery (n=17) and/or lifelong suppressive antibiotic treatment (n=6). Variables independently associated with failure: previous surgery on the prosthetic joint (OR: 6.3 [1.8-22.3]), Staphylococcus aureus PJI (OR: 9.4 [1.6-53.9]), post-debridement antibiotic treatment for \textless3 months (OR: 20.0 [2.2-200]). CONCLUSION: Previous surgery, S. aureus PJI, and short duration antibiotic treatment are associated with an increased risk of failure after debridemen

L’ingénierie écologique appliquée aux zones de rejet végétalisées : élimination de micropolluants, biodiversité et intégration socio-territoriale

International audienc