Development of modular expression across phylogenetically distinct diazotrophs.

Unlabelled: Diazotrophic bacteria can reduce atmospheric nitrogen into ammonia enabling bioavailability of the essential element. Many diazotrophs closely associate with plant roots increasing nitrogen availability, acting as plant growth promoters. These associations have the potential to reduce the need for costly synthetic fertilizers if they could be engineered for agricultural applications.

Emergence of an Orphan Nitrogenase Protein Following Atmospheric Oxygenation.

Molecular innovations within key metabolisms can have profound impacts on element cycling and ecological distribution. Yet, much of the molecular foundations of early evolved enzymes and metabolisms are unknown. Here, we bring one such mystery to relief by probing the birth and evolution of the G-subunit protein, an integral component of certain members of the nitrogenase family, the only enzymes capable of biological nitrogen fixation.

Regulatory response to a hybrid ancestral nitrogenase in .

Biological nitrogen fixation, the microbial reduction of atmospheric nitrogen to bioavailable ammonia, represents both a major limitation on biological productivity and a highly desirable engineering target for synthetic biology. However, the engineering of nitrogen fixation requires an integrated understanding of how the gene regulatory dynamics of host diazotrophs respond across sequence-function space of its central catalytic metalloenzyme, nitrogenase. Here, we interrogate this relationship by analyzing the transcriptome of engineered with a phylogenetically inferred ancestral nitrogenase protein variant.

Nitrogenase resurrection and the evolution of a singular enzymatic mechanism.

The planetary biosphere is powered by a suite of key metabolic innovations that emerged early in the history of life. However, it is unknown whether life has always followed the same set of strategies for performing these critical tasks. Today, microbes access atmospheric sources of bioessential nitrogen through the activities of just one family of enzymes, nitrogenases.

Automated Laboratory Growth Assessment and Maintenance of Azotobacter vinelandii.

Azotobacter vinelandii (A. vinelandii) is a commonly used model organism for the study of aerobic respiration, the bacterial production of several industrially relevant compounds, and, perhaps most significantly, the genetics and biochemistry of biological nitrogen fixation. Laboratory growth assessments of A.

Metabolism and genotoxicity of polycyclic aromatic hydrocarbons in human skin explants: mixture effects and modulation by sunlight.

Cutaneous exposure to carcinogenic polycyclic aromatic hydrocarbons (PAH) occurs frequently in the industrialized workplace. In the present study, we addressed this topic in a series of experiments using human skin explants and organic extracts of relevant industrial products. PAH mixtures were applied topically in volumes containing either 10 or 1 nmol B[a]P.

Influence of exposure dose, complex mixture, and ultraviolet radiation on skin absorption and bioactivation of polycyclic aromatic hydrocarbons ex vivo.

Combined exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAHs) and ultraviolet radiation (UVR) is suspected to enhance PAH skin permeability and skin cancer risk depending on PAH bioactivation. The impact of PAH mixtures (exposure dose, composition, and complexity) and UVR was assessed for PAH cutaneous absorption and metabolism using realistic exposure conditions and human skin explants. PAH complex mixtures were extracted from the industrial products coal tar pitch (CTP-I) and petroleum coke (PC-I).

Indoor air quality in two French hospitals: Measurement of chemical and microbiological contaminants.

In addition to being influenced by the environment, the indoor air pollution in hospitals may be associated with specific compounds emitted from various products used, health care activities and building materials. This study has enabled assessment of the chemical and microbiological concentrations of indoor air in two French hospitals. Based on an integrated approach, the methodology defined aims to measure concentrations of a wide range of chemical compounds (>50 volatile and semi-volatile organic compounds), particle concentrations (PM and PM), microorganisms (fungi, bacteria and viruses) and ambient parameters (temperature, relative humidity, pressure and carbon dioxide).

Update on Actinomucor elegans, a mucormycete infrequently detected in human specimens: how combined microbiological tools contribute efficiently to a more accurate medical care.

Actinomucor elegans is a fungus belonging to mucormycetes and is still probably underdiagnosed due to misidentification. Based on a recent first case of Actinomucor elegans sinusitis in Europe, in an immunocompromised patient under voriconazole treatment, this paper aims to summarize knowledge about A. elegans mucormycoses.

Water and surface microbiologic quality of point-of-use water filters: A comparative study.

Waterborne pathogens, such Legionella pneumophila and Pseudomonas aeruginosa, are major contributors to hospital-associated infection. Point-of-use water filtration has demonstrated benefits to prevent infection implicating waterborne pathogens. Despite the quality of the filters, misuse may expose patients to these pathogens.

Microbial control of dental unit water: Feedback on different disinfection methods experience.

A water quality study of dental units showed biofilm and opportunistic microorganisms. We report the steps that ultimately allowed us to obtain water quality as water for standard care with no pathogens throughout all dental units. In summary, treatment with continuous disinfection associated with use of sterile water allowed us to restore the water quality at the output of dental care units while ensuring the safety of care.

[Hepatic alveolar echinococcosis: a rare cause of recurrent, surgically curable abdominal pain in children].

Hepatic alveolar echinococcosis is a rare parasitic zoonosis, potentially lethal in childhood. It is due to Echinococcosis multilocularis whose larva insidiously develops in the liver. We report the case of a 13-year-old girl, living in the Vosges Mountains, followed for recurrent abdominal pain, with recent worsening.

Focus on invasive mucormycosis in paediatric haematology oncology patients: a series of 11 cases.

Mucormycosis has emerged as an increasingly important infection in oncology centres with high mortality, especially in severely immunocompromised patients. We carried out a retrospective study of 11 children with mucormycosis treated in seven French oncology-haematology paediatric wards during the period from 1991 to 2011. Lichtheimia corymbifera and Mucor spp.

Emergence of disseminated infections due to Geosmithia argillacea in patients with chronic granulomatous disease receiving long-term azole antifungal prophylaxis.

We report two cases of invasive infections due to Geosmithia argillacea, an emerging mold, in patients with chronic granulomatous disease receiving prolonged azole antifungal prophylaxis. One patient died despite receiving a combination of four antifungals, and the other developed cerebral and medullary lesions under a combination of caspofungin, posaconazole, terbinafine, and gamma interferon.

Exit of GPI-anchored proteins from the ER differs in yeast and mammalian cells.

Previous studies have shown that yeast glycosylphosphatidylinositol-anchored proteins (GPI-APs) and other secretory proteins are preferentially incorporated into distinct coat protein II (COPII) vesicle populations for their transport from the endoplasmic reticulum (ER) to the Golgi apparatus, and that incorporation of yeast GPI-APs into COPII vesicles requires specific lipid interactions. We compared the ER exit mechanism and segregation of GPI-APs from other secretory proteins in mammalian and yeast cells. We find that, unlike yeast, ER-to-Golgi transport of GPI-APs in mammalian cells does not depend on sphingolipid synthesis.

[Initiation and duration of breastfeeding in obstetrical hospitals of Aix-Chambery (France)].

Unlabelled: Our objectives were to estimate duration of breastfeeding and to identify factors associated with initiation and weaning.

Methods: A prospective study was carried out among 353 mothers delivering in three obstetric hospitals at Aix-Chambery (Savoie, France). Breastfeeding was considered as survival data with censored observations.

Endothelial cell activation by myeloblasts: molecular mechanisms of leukostasis and leukemic cell dissemination.

Leukostasis and tissue infiltration by leukemic cells are poorly understood life-threatening complications of acute leukemia. This study has tested the hypothesis that adhesion receptors and cytokines secreted by blast cells play central roles in these reactions. Immunophenotypic studies showed that acute myeloid leukemia (AML) cells (n = 78) of the M0 to M5 subtypes of the French-American-British Cooperative Group expressed various amounts of adhesion receptors, including CD11a, b, c/CD18, CD49d, e, f/CD29, CD54, sCD15, and L-selectin.

Inhibition of selectin-mediated cell adhesion and prevention of acute inflammation by nonanticoagulant sulfated saccharides. Studies with carboxyl-reduced and sulfated heparin and with trestatin a sulfate.

Selectins play a major role in the inflammatory reaction by initiating neutrophil attachment to activated vascular endothelium. Some heparin preparations can interact with L- and P-selectin; however, the determinants required for inhibiting selectin-mediated cell adhesion have not yet been characterized. We now report that carboxyl-reduced and sulfated heparin (prepared by chemical modifications of porcine intestinal mucosal heparin leading to the replacement of carboxylates by O-sulfate groups) and trestatin A sulfate (obtained by sulfation of trestatin A, a non-uronic pseudo-nonasaccharide extracted from Streptomyces dimorphogenes) exhibit strong anti-P-selectin and anti-L-selectin activity while lacking antithrombin-mediated anticoagulant activity.

Seasonal variations of interleukin-4 and interferon-gamma release by peripheral blood mononuclear cells from atopic subjects stimulated by polyclonal activators.

IgE synthesis is controlled by interleukin (IL)-4 and interferon (IFN)-gamma, but there is heterogeneity in the IL-4 response depending on the sensitization of patients and natural allergen exposure. In patients sensitized to various allergens, we studied the synthesis of IL-4, IFN-gamma, and IgE to determine to what extent their in vitro immune response may be influenced by pollen season, depending on their sensitization. We studied 12 nonallergic individuals, seven patients sensitized to cypress pollen, 12 sensitized to grass pollen, 14 sensitized to several pollens, and 42 patients with polysensitization.