Characterization of the liver cytochrome P450 in the marine fish Mugil cephalus and effects of some hydrocarbons on the mixed-function oxidase components

The marine fish Mugil cephalus was caught in the Bay of Marseilles (France) in 1985 and the liver microsomal cytochrome P₄₅₀ was identified at a concentration of about 0.230 nmol mg^-1 protein. Optimal assay conditions were established to measure two mixed-function cytochrome P₄₅₀-dependent oxidases: aniline hydroxylase and p-nitroanisole O-demethylase. Induction of cytochrome P₄₅₀ occurred after exposure of mullet to an aromatic hydrocarbon and a water-soluble petroleum fraction. The liver cytochrome P₄₅₀ was solubilized and purified. The monomer molecular weight of partially purified cytochrome P₄₅₀, determined by sodium dodecyl-sulfate-gel electrophoresis, was 51 000.     

Effects of ultraviolet light (315 nm), temperature and relative humidity on the degradation of polylactic acid plastic films

The influence of temperature (30, 45 and 60 degrees C) and relative humidity (RH) (30%, 50% and 100%) on the degradation of poly(l-lactic acid) (PLA) films were studied. In addition, the effects of ultraviolet (UV) light (315 nm) on the degradation of PLA films were also analyzed. Various analytical techniques were applied to observe changes in the properties of PLA polymer films. FTIR spectroscopy was used as semi-quantitative method to get information about the chemistry of the degradative process. The degradation rate of PLA was enhanced by increasing temperature and RH, factors responsible for a faster reduction of the weight-average molecular weight (M(W)), of the glass transition temperature (Tg) and of the percentage of elongation at break. Moreover, UV treatment accelerated these phenomena.     

Seamount endemism questioned by the geographic distribution and population genetic structure of marine invertebrates

Previous studies have suggested that the high diversity associated with the Norfolk seamounts (Southwest Pacific) could reflect endemism resulting from limited dispersal due to hydrological phenomena. Crustaceans of the family Galatheidae are thoroughly studied in the New Caledonia economic zone permitting the analysis of species distribution pattern between the New Caledonia slope and Norfolk ridge seamounts. This analysis has shown that, qualitatively, the same species are sampled on seamounts and on the New Caledonia slope. Local endemism was never detected. However, on each seamount, and therefore on a small surface, a very high number of species are usually sampled, suggesting that seamounts are biodiversity hot spots. Then, to evaluate whether the seamounts constitute patches of isolated habitat, we explore the pattern of genetic diversity within several species of crustaceans and gastropods. Analysis of the intra-specific genetic structure using the mitochondrial marker COI reveals that populations of two Galatheidae species (Munida thoe and Munida zebra), polymorphic for this marker, are genetically not structured, both among seamounts and between the seamounts and the island slope. The genetic structure over a similar sampling scheme of two Eumunida species (Chirostylidae, the sister family of Galatheidae) and a planktotrophic gastropod (Sassia remensa) reveals a similar pattern. Population structure is observed only in Nassaria problematica, a non-planktotrophic gastropod with limited larvae dispersal. Thus, the limitation of gene flow between seamounts appears to be observed only for species with limited dispersal abilities. Our results suggest that the Norfolk seamounts rather than functioning as areas of endemism, instead, may be highly productive zones that can support numerous species in small areas.     

Effects of petroleum hydrocarbons on the cytochrome P450 content of the mollusc bivalveMytilus galloprovincialis

The cytochrome P₄₅₀, identified by the characteristic 450 nm spectral peak of its carbon monoxide complex, was detected in the hepatopancreatic microsomes ofMytilus galloprovincialis, collected from Ponteau (Bay of Fos, France) in 1982 and 1983. When mussels were exposed to a variety of petroleum hydrocarbons, the cytochrome P₄₅₀ content increased. It is shown that aromatic hydrocarbons are more effective than alkanes in inducing a high level of cytochrome P₄₅₀. The possible use of this haemoprotein in hydrocarbon pollutant detection is discussed.     

Implementation of a medical command and control team in Switzerland

In case of a major incident or disaster, the advance medical rescue command needs to manage several essential tasks simultaneously. These include the rapid deployment of ambulance, police, fire and evacuation services, and their coordinated activity, as well as triage and emergency medical care on site. The structure of such a medical rescue command is crucial for the successful outcome of medical evacuation at major incidents. However, little data has been published on the nature and structure of the command itself. This study presents a flexible approach to command structure, with two command heads: one emergency physician and one experienced paramedic. This approach is especially suitable for Switzerland, whose federal system allows for different structures in each canton. This article examines the development of these structures and their efficiency, adaptability and limitations with respect to major incident response in the French‐speaking part of the country.     

Photodegradation of the organophosphorus pesticides chlorpyrifos,fenamiphos and vamidothion in water

The photodegradation of the pesticides chlorpyrifos, fenamiphos and vamidothion in water containing 2–4% methanol was examined. Acetone (5%) was added as photosensitizer in the photolysis of vamidothion. A suntest apparatus equipped with a xenon arc lamp which exhibits a radiation very close to natural sunlight was employed. Analyses were performed by direct injection of the water samples containing the photoproducts into a liquid chromatograph with diode array and thermospray mass spectrometric detection. The major photodegradation products were identified by matching their diode‐array spectra with the corresponding spectra of the authentic standards, their retention times and the spectra obtained using positive and/or negative thermospray mass spectrometry. 3,5,6‐trichloro‐2‐pyridinol, fenamiphos sulfoxide and vamidothion sulfoxide were the major photodegradation products from chlorpyrifos, fenamiphos and vamidothion, respectively.     

In-vitro study of interaction between photooxidation and biodegradation of 2-methylphenanthrene by Sphingomonas SP. 2MPII

This work reports a study of interactions between reactions of photooxidation and reactions of bacterial degradation of an alkylated polyaromatic hydrocarbon (2-methylphenanthrene). Bacterial growth was carried out using artificial sunlight as light source. Among the various products detected, the major product was identified as the 2-methylphenanthrene aldehyde. Sunlight allows accelerated elimination of the substrate. This enhancement of the biodegradation rate of 2 methylphenanthrene is due to the use of assimilable photoproducts by the bacterium.     

Inter-laboratory validation of an ISO test method for measuring enzyme activities in soil samples using colorimetric substrates

Environmental Science and Pollution Research - The evaluation of soil quality requires the use of robust methods to assess biologically based indicators. Among them, enzyme activities are used for...