Reliable determination of the growth and hydrogen production parameters of the photosynthetic bacterium in fed batch culture using a combination of the Gompertz function and the Luedeking-Piret model.

In this study, experimental results of hydrogen producing process based on anaerobic photosynthesis using the purple non-sulfur bacterium are scrutinized. The bacterial culture was carried out in a photo-bioreactor operated in a quasi-continuous mode, using lactate as a carbon source. The method is based on the continuous stirred tank reactors (CSTR) technique to access kinetic parameters.

H production by photofermentation in an innovative plate-type photobioreactor with meandering channels.

Hydrogen production by Rhodobacter capsulatus is an anaerobic, photobiological process requiring specific mixing conditions. In this study, an innovative design of a photobioreactor is proposed. The design is based on a plate-type photobioreactor with an interconnected meandering channel to allow culture mixing and H degassing.

Graduates' affective transfer of research skills and evidence based practice from university to employment in clinics.

Background: This research sought to determine the impact of explicit program-based development of skills associated with research and Evidence Based Practice (EBP) on the attitudes and sustained behaviours of graduates subsequently employed in clinics. Systematic reviews have shown that university teaching of EBP and research skills rarely result in transfer of commensurate attitudes and sustained behaviours of students to their subsequent studies or to employment. Studies have therefore called for detailed exploration of what may enable this transfer of knowledge and skills to attitudes and behaviours.

Mechanistic Details of Early Steps in Coenzyme Q Biosynthesis Pathway in Yeast.

Coenzyme Q (Q) is a redox lipid that is central for the energetic metabolism of eukaryotes. The biosynthesis of Q from the aromatic precursor 4-hydroxybenzoic acid (4-HB) is understood fairly well. However, biosynthetic details of how 4-HB is produced from tyrosine remain elusive.

Metabolic modelling in a dynamic evolutionary framework predicts adaptive diversification of bacteria in a long-term evolution experiment.

Background: Predicting adaptive trajectories is a major goal of evolutionary biology and useful for practical applications. Systems biology has enabled the development of genome-scale metabolic models. However, analysing these models via flux balance analysis (FBA) cannot predict many evolutionary outcomes including adaptive diversification, whereby an ancestral lineage diverges to fill multiple niches.

Metabolic and immune impairments induced by the endocrine disruptors benzo[a]pyrene and triclosan in Xenopus tropicalis.

Despite numerous studies suggesting that amphibians are highly sensitive to cumulative anthropogenic stresses, the role played by endocrine disruptors (EDs) in the decline of amphibian populations remains unclear. EDs have been extensively studied in adult amphibians for their capacity to disturb reproduction by interfering with the sexual hormone axis. Here, we studied the in vivo responses of Xenopus tropicalis males exposed to environmentally relevant concentrations of each ED, benzo[a]pyrene (BaP) and triclosan (TCS) alone (10 μg L(-1)) or a mixture of the two (10 μg L(-1) each) over a 24 h exposure period by following the modulation of the transcription of key genes involved in metabolic, sexual and immunity processes and the cellular changes in liver, spleen and testis.

Zinc biosorption by the purple non-sulfur bacterium Rhodobacter capsulatus.

This paper presents the first report providing information on the zinc (Zn) biosorption potentialities of the purple non-sulfur bacterium Rhodobacter capsulatus. The effects of various biological, physical, and chemical parameters on Zn biosorption were studied in both the wild-type strain B10 and a strain, RC220, lacking the endogenous plasmid. At an initial Zn concentration of 10 mg·L(-1), the Zn biosorption capacity at pH 7 for bacterial biomass grown in synthetic medium containing lactate as carbon source was 17 and 16 mg Zn·(g dry mass)(-1) for strains B10 and RC220, respectively.

Zinc and lead leaching from contaminated industrial waste sludges using coupled processes.

Metal pollution of solid matrices, like soils, sediments and sludge, is widespread across the globe, and the clean-up of these matrices presents many difficulties. The aim of this study was to develop an efficient leaching technique for metal removal from an industrial carbon sludge contaminated with Zn (8600 mg kg(-1)) and Pb (389 mg kg(-1)). To this end, the possibility of coupling processes, such as extraction with mineral acids, EDTA addition, ultrasound and bioleaching, was investigated.

Effectiveness of ultrasound for the destruction of Mycobacterium sp. strain (6PY1).

Ultrasound is widely used to disinfect drinking water and wastewater due to its strong physical and chemical effects on microorganisms. The aim of this study was to investigate the effect of ultrasound on the destruction of Mycobacterium strain 6PY1. Ultrasound waves (20 kHz or 612 kHz) were used to treat aqueous suspensions of Mycobacterium at different volumes, initial bacterial concentrations, and power densities.

Ubiquitous water-soluble molecules in aquatic plant exudates determine specific insect attraction.

Plants produce semio-chemicals that directly influence insect attraction and/or repulsion. Generally, this attraction is closely associated with herbivory and has been studied mainly under atmospheric conditions. On the other hand, the relationship between aquatic plants and insects has been little studied.

Adaptation of a Mycobacterium strain to phenanthrene degradation in a biphasic culture system: influence on interfacial area and droplet size.

A phenanthrene-degrading Mycobacterium sp. strain 6PY1 was grown in an aqueous/organic biphasic culture system with phenanthrene as sole carbon source. Its capacity of degradation was studied during sequential inoculum enrichments, reaching complete phenanthrene degradation at a maximim rate of 7 mg l(-1) h(-1).

Optimization and modeling of phenanthrene degradation by Mycobacterium sp. 6PY1 in a biphasic medium using response-surface methodology.

In the present paper, the degradation of phenanthrene, a model polycyclic aromatic hydrocarbon compound, by the Mycobacterium strain 6PY1 was optimized in a biphasic culture medium. The optimization and modeling were performed using the design of experiments methodology. The temperature, the silicone oil/mineral salts medium volume ratio, and the initial cell concentration, were used as the central composite design parameters.

Soil distribution of fipronil and its metabolites originating from a seed-coated formulation.

Seed-coating with the insecticide fipronil has been intensively used in sunflower cultivation to control soil pests such as wireworms. A research project was undertaken to determine the soil distribution of fipronil and of its main phenylpyrazole metabolites. Under agronomic conditions, the quantity of fipronil in the seed-coat (437 microg/seed) decreased continuously during the cultivation period (3.

Phototransformation of the insecticide fipronil: identification of novel photoproducts and evidence for an alternative pathway of photodegradation.

Fipronil is a recently discovered insecticide of the phenylpyrazole series. It has a highly selective biochemical mode of action, which has led to its use in a large number of important agronomical, household, and veterinary applications. Previous studies have shown that, during exposure to light, fipronil is converted into a desulfurated derivative (desulfinyl-fipronil), which has slightly reduced insecticidal activity.

Stimulation of pyrene mineralization in freshwater sediments by bacterial and plant bioaugmentation.

As a means to study the fate of polycyclic aromatic hydrocarbons (PAHs) in freshwater sediments, pyrene mineralization was examined in microcosms spiked with [14C]pyrene. Some microcosms were planted with reeds (Phragmites australis) and/or inoculated with a pyrene-degrading strain, Mycobacterium sp. 6PY1.

Isolation and characterization of a novel sphingomonad capable of growth with chrysene as sole carbon and energy source.

A bacterial strain able to grow in pure culture with chrysene as sole added carbon and energy source was isolated from PAH-contaminated soil after successive enrichment cultures in a biphasic growth medium. Initially, growth occurred in the form of a biofilm at the interface between the aqueous and non-aqueous liquid phases. However, after a certain time, a transition occurred in the enrichment cultures, with growth occurring in suspension and a concomitant increase in the rate of chrysene degradation.

Identification and functional analysis of two aromatic-ring-hydroxylating dioxygenases from a sphingomonas strain that degrades various polycyclic aromatic hydrocarbons.

In this study, the enzymes involved in polycyclic aromatic hydrocarbon (PAH) degradation in the chrysene-degrading organism Sphingomonas sp. strain CHY-1 were investigated. [14C]chrysene mineralization experiments showed that PAH-grown bacteria produced high levels of chrysene-catabolic activity.

Identification of pyrene-induced proteins in Mycobacterium sp. strain 6PY1: evidence for two ring-hydroxylating dioxygenases.

In this study, the enzymes involved in polycyclic aromatic hydrocarbon (PAH) degradation were investigated in the pyrene-degrading Mycobacterium sp. strain 6PY1. [(14)C]pyrene mineralization experiments showed that bacteria grown with either pyrene or phenanthrene produced high levels of pyrene-catabolic activity but that acetate-grown cells had no activity.

Molecular sequence analysis of prokaryotic diversity in the anoxic sediments underlying cyanobacterial mats of two hypersaline ponds in Mediterranean salterns.

Abstract Small-subunit (16S) ribosomal DNA clone libraries were constructed using DNA isolated from the anoxic sediments underlying the cyanobacterial mats from two sampling stations of different salinity (Station A, 150-200 per thousand salinity; Station B, 250-320 per thousand salinity) located in the Mediterranean salterns of Salin-de-Giraud (France). Previous studies have shown that the mats at these two sites differ greatly in physicochemical and microbial composition. Sequence analysis of the clone libraries indicated that prokaryotic diversity was high in the sediments from both stations, in both the Bacteria and Archaea domains.

Isolation and characterization of spirilloid purple phototrophic bacteria forming red layers in microbial mats of Mediterranean salterns: description of Halorhodospira neutriphila sp. nov. and emendation of the genus Halorhodospira.

Microbial mats developing in the hypersaline lagoons of a commercial saltern in the Salin-de-Giraud (Rhône delta) were found to contain a red layer fully dominated by spirilloid phototrophic purple bacteria underlying a cyanobacterial layer. From this layer four strains of spirilloid purple bacteria were isolated, all of which were extremely halophilic. All strains were isolated by using the same medium under halophilic photolithoheterotrophic conditions.

Characterization of three spiral-shaped purple nonsulfur bacteria isolated from coastal lagoon sediments, saline sulfur springs, and microbial mats: emended description of the genus Roseospira and description of Roseospira marina sp. nov., Roseospira navarrensis sp. nov., and Roseospira thiosulfatophila sp. nov.

Three new spirilloid phototrophic purple nonsulfur bacteria were isolated in pure culture from three different environments: strain CE2105 from a brackish lagoon in the Arcachon Bay (Atlantic coast, France), strain SE3104 from a saline sulfur spring in the Pyrenees (Navarra, Spain), and strain AT2115 a microbial mat (Tetiaroa Atoll, Society Islands). Single cells of the three strains were spiral-shaped and highly motile. Their intracellular photosynthetic membranes were of the vesicular type.