Influence of hydrostatic pressure on l-glutamate dehydrogenase from the Antarctic fish Chaenocephalus aceratus

The influence of hydrostatic pressure on the stability and activity of glutamate dehydrogenase (GDH) from the liver of the Antarctic fish Chaenocephalus aceratus (Notothenioidei: Channichthyidae) has been investigated using the homologous bovine enzyme for comparison. At gradually increasing pressure, the fish GDH retains all activity up to 140 MPa, whereas in the same pressure range the bovine enzyme is slightly inactivated. The kinetics of pressure-induced inactivation of Antarctic GDH displays an exponentially decreasing residual activity as a function of the incubation time, whereas the bovine enzyme shows a complex pattern of behaviour in the first 20 min of incubation, attributable to the transient formation of aggregates. The coenzyme NAD increases the stability of both enzymes. The activation volume calculated for the reaction catalysed under pressure by fish GDH is higher than that of the bovine enzyme. These results indicate that the molecular properties of fish and bovine GDH are affected differently by hydrostatic pressure. A common mode of inactivation under extreme conditions of pressure and temperature of the cold-adapted Antarctic fish and mesophilic bovine GDH is deduced and discussed. Received: 20 October 1998 / Accepted: 7 May 1999     

Rapid ethnobotanical diagnosis of the Fulni-? Indigenous lands (NE Brazil): floristic survey and local conservation priorities for medicinal plants

This study was developed as part of the project ??Studies for Environmental and Cultural Sustainability of the Fulni-ô Medical System: Office on handling medicinal plants??. The Fulni-ô people are located in Pernambuco State, Northeastern Brazil. One of the components of this project was an ethnobotanical diagnosis of the indigenous land, where a phytosociological survey was performed in an area of Caatinga vegetation, located at Ouricuri settlement. Based on these ethnobotanical data, we calculated a conservation priority index aiming to rank species that should receive immediate attention from the Fulni-ô people. We identified 44 woody plants, 50% of which have a medicinal use. Among these, six plants were considered highly vulnerable and in need of immediate conservationist attention, in order to ensure the perpetuation of these species and the sustainability of traditional therapeutic practices of the Fulni-ô: Anadenanthera colubrina, Myracrodruon urundeuva, Lippia sp., Spondias tuberosa, Maytenus rigida, and Sideroxylon obtusifolium. We recommend the direct involvement of the Fulni-ô people in the conservation and the management of local resources by implementing a management plan and monitoring strategies for the populations of plants considered most important by the indigenous group.     

Pesticide pressure and fish farming in barrage pond in Northeastern France Part I: site characterization and water quality

Purpose

Fish farming in barrage pond is a rearing system commonly used worldwide. Obtaining good water quality is essential to improve sustainability of these ecosystems, both for health of fish consumers and environmental considerations. However, ponds are often located in agricultural landscape, but few study reports impact of pesticide pressure on these ecosystems. This study characterizes five sites in Northeastern France. This work establishes an initial framework for pesticide monitoring with the aim to improve understanding of the fate of pesticides in ponds.

Methods

This framework is based on surveys indicating managements and Geographical Information System (GIS) for five ponds and their watersheds (sites: C-0, C-25, C-45, C-75 and C-85) and completes with some analysis of a large spectrum of pesticide residues in surface waters.

Results

Watersheds show a gradient of crop proportion ranging from 0% to 82% of the watershed area, mainly rapeseed, wheat, barley and maize. Ponds were representative of local Northeastern France management. Many pesticides, and also nutrients, were measured in water with concentrations varying between sites and seasons. The sum of quantified molecules ranged from 0.17 ??g/l for site C-0 (March) to 8.81 ??g/l for site C-25 (October). Concentrations of metaldehyde, quinmerac, isoproturon and bentazon were sometimes above 1 ??g/l.

Conclusions

There is a strong connection between pond and watershed, due to water supply throughout the fish production cycle. Sites with small pond/big watershed are the most exposed to acute contamination a few days after spraying because water discharges are not diluted.     

Assessment of DDT, DDE, and 1-hydroxypyrene levels in blood and urine samples in children from Chiapas Mexico

Purpose

The aim of this study was assess co-exposure to DDT, DDE (main DDT metabolite), and PAHs (1-hydroxypyrene) in areas where biomass is used to cook and to heat homes and where DDT was used to combat malaria transmission.

Methods

During 2009, we analyzed a total of 190 blood and urine samples from children living in six communities in Mexico. Quantitative analyses of DDT and DDE were performed using gas chromatography coupled with mass spectrometry. Analyses of 1-hydroxypyrene were performed by HPLC using a fluorescence detector.

Results

In this work, we found high levels of DDT and its principal metabolite (DDE) in the blood of children living in four communities in Chiapas located in the southeastern region of Mexico (range, Conclusion This study demonstrates that children in these communities were exposed to DDT and its metabolites, and to other contaminants generated by the combustion of firewood. Therefore, the complex mixture studied in this study (PAHs and DDT/DDE) requires further research.     

Exposure of ruminants to persistent organic pollutants and potential of decontamination

Human activities are emitting persistent organic pollutants (POPs) to the environment. These compounds have raised concerns about the risk of transfer through the food chain via animal products. They are characterized by a strong persistence in environmental matrices and a lipophilicity which may lead to their accumulation in fat tissues. In EU Regulations (no. 1881/2006, 1259/2011), maximum acceptable levels for polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs), and dioxin-like or nondioxin-like polychlorinated biphenyls (PCBs) in food of animal origin have been set. Transfer rates from contaminated fodder to milk have been established: for PCBs, the rate of transfer varies from 5 to 90 % and for PCDD/Fs from 1 to 40 %. The differential transfer of the compounds towards milk is related to the hydrophobicity of the pollutants and to their metabolic susceptibility. According to numerous authors, soil is the major reservoir for POPs, and its involuntary ingestion by farm animals reared outdoors may be the main cause of animal product contamination (meat, milk, or eggs). Recent studies seem to indicate that soil is a real risk matrix in terms of transfer of pollutants to the food chain. A POP crisis management is extremely difficult, since it impacts many farmers located in the contaminated area. The question arising is to know if livestock contaminated by POPs may be decontaminated and further used for their initial purpose. Recent data demonstrate that the decontamination process appear feasible and depends on initial level of contamination or the physiological status of the animals.     

The enzymes involved in synthesis and utilization of carbamylphosphate in the deep-sea tube worm Riftia pachyptila

 The obligate symbiosis of the deep-sea tube worm Riftia pachyptila with a sulphur-oxidizing bacterium raises important questions concerning its metabolism and metabolic exchanges. In this study, the presence and properties of the enzymes synthesizing and utilizing carbamylphosphate in the arginine and pyrimidine nucleotide pathways were investigated in this worm. The results show that the ammonium-dependent carbamylphosphate synthetase and ornithine transcarbamylase, enzymes involved in the arginine pathway, are present in all body parts of the worm. In contrast, the glutamine-dependent carbamylphosphate synthetase and aspartate transcarbamylase, enzymes involved in the de novo pathway for pyrimidine nucleotides biosynthesis, are present only in the trophosome, the symbiont-harbouring tissue. Although the bacterial nature of these enzymes is not unambigously established, these results strongly suggest that the de novo biosynthesis of pyrimidine nucleotides is limited to the trophosome, the organ where the production of metabolic energy takes place, while the other parts of the worm's body rely on the salvage pathway for the production of the pyrimidine triphosphate nucleotides. Received: 22 June 1998 / Accepted: 26 October 1999     

Are motorway wildlife passages worth building? Vertebrate use of road-crossing structures on a Spanish motorway

Numerous road and railway construction projects include costly mitigation measures to offset the barrier effect produced on local fauna, despite the scarcity of data on the effectiveness of such mitigation measures. In this study, we evaluate the utility of different types of crossing structures. Vertebrate use of 43 transverse crossing structures along the A-52 motorway (north-western Spain) was studied during spring 2001. Research centered on wildlife passages (9), wildlife-adapted box culverts (7), functional passages (6 overpasses, 7 underpasses) and culverts (14), with marble dust being used to record animal tracks. A total of 424 track-days were recorded, with most of the larger vertebrate groups present in the area being detected. All crossing structure types were used by animals, although the intensity of use varied significantly among them (Kruskal-Wallis test, p<0.05); culverts were used less frequently than other structures. Crossing structure type and width were identified as the most important factors in their selection for use. Wildlife passages and adapted culverts allowed crossing by certain species (wild boar, roe deer, Eurasian badger), which do not tend to cross elsewhere. These results highlight the importance of using both mixed-type structures and wildlife passages in reducing the barrier effect of roads.     

Populations of the Sydney rock oyster, Saccostrea glomerata, vary in response to ocean acidification

Acidifying oceans are predicted to fundamentally alter marine ecosystems. Over the next century, acute studies suggest that the impacts of climate change on marine organisms and ecosystems may be catastrophic. To date, however, little is known about whether the response of marine organisms varies within a species and whether this provides a potential ??adaptive capacity??. Here, we show that selectively bred lines of the ecologically and economically important estuarine mollusc, the Sydney rock oyster Saccostrea glomerata, are more resilient to ocean acidification than the wild populations. When reared at elevated pCO₂, we found a 25% reduction in shell growth of the selectively bred population of the Sydney rock oyster, Saccostrea glomerata, compared to a 64% reduction in shell growth of wild populations. This study shows that there are significantly different sensitivities to ocean acidification even within the same species, providing preliminary evidence that selective breeding may be a solution for important aquaculture industries to overcome the future effects of ocean acidification.     

Laser-induced fluorescence of polycyclic aromatic hydrocarbons: an approach to gas standards

Rapid methods are needed to analyse air pollutants such as polycyclic aromatic hydrocarbons (PAHs). Reliable semi-quantitative gas standards were required for the development of a laser-induced fluorescence (LIF) method for polycyclic aromatic hydrocarbon analysis, based on sampling of air onto multi-channel polydimethylsiloxane rubber traps. Easily constructed diffusion tubes provided naphthalene vapour at ~2 ng s⁻¹. A gas chromatographic fraction collection method for loading less volatile PAHs onto the traps from a flame ionization detector outlet was developed and optimized. The accuracy of the method, which can be further optimized, was sufficient for initial LIF screening tests to flag samples exceeding threshold PAH levels for subsequent quantitative GC–MS analysis.