Characterisation of DNA probes for the analysis of metallothionein gene expression in the bank vole (Clethrionomys glareolus)

DNA probes have been developed for subsequent use in monitoring the exposure of animals to heavy metal pollution in terrestrial environments using metallothionein (MT) gene expression in the bank vole (Clethrionomys glareolus). Three different bank vole sequences were characterised corresponding to the cDNA and the genomic DNA for MT-I and the genomic DNA for MT-II. Nucleotide sequence analysis indicates that the coding sequences of the bank vole MT-I and MT-II genes exhibit a very high degree of similarity (greater than 92%) to the corresponding genes of the Chinese hamster, the mouse and the rat. In common with other mammalian MT genes, both the MT-I and MT-II genes in the bank vole are interrupted by two introns, which are at identical positions as those in other rodent MT genes; furthermore, the sizes of these introns are similar to those in other rodents with the first intron being larger than the second and those in the MT-I gene being larger than those in the MT-II gene. The predicted amino acid sequence for the proteins shows that both proteins contain 20 cysteine residues at positions identical to those in other known mammalian MTs. The availability of these DNA sequences now provides a good opportunity to investigate MT gene expression and possible gene amplification in bank voles exposed to metal pollution.     

An Ecological Integrity Index for Littoral Wetlands in Agricultural Catchments of Semiarid Mediterranean Regions

The main goal of the present study was to develop an ecological integrity index for littoral wetland management and conservation in semiarid Mediterranean areas that have been highly impacted by agriculture, including the selection of pressure and state indicators at landscape and wetlands scales that reflect the status, condition, and trends of wetlands ecosystems. We used a causality framework based on the relationship between pressure of anthropogenic activities and the ecological state of wetlands and their catchments, integrating environmental, biologic, economic, and social issues. From the application of 51 indicators in 7 littoral wetlands in the southeastern Iberian Peninsula, we selected 12 indicators (5 at catchment scale and 7 at wetland scale) to constitute the ecological integrity index proposed. The potential nitrogen export per area at catchment scale and the potential relative nitrogen export from the area surrounding the wetlands were the best pressure single predictors of state indicators with a causal relationship with environmental meaning. Wetlands in catchments with more agriculture had less ecological integrity than those in less impacted areas. A wide riparian zone in some wetlands acts as a buffer area, diminishing the effects of intensive agriculture. The index of ecological integrity developed here has a number of essential characteristics that make it a useful tool for ecosystem managers and decision-makers. The index can be used to (1) assess and control ecological integrity, (2) diagnose probable causes of ecological impairment, (3) establish criteria for protecting and restoring wetland ecosystems, and (4) integrate catchment management. Published online     

Vitellogenin induction in Cyprinus carpio treated with 17beta-estradiol and 4-nonylphenol

The aim of the present study was to demonstrate induction ofvitellogenin in the common carp (Cyprinus carpio) as abiomarker for monitoring freshwater ecosystems. Sexually undifferentiated specimens of common carp were treated experimentally with 17-estradiol and increasing doses of 4-nonylphenol and levels of plasma Vtg were measured in orderto: 1) validate an ELISA assay for plasma Vtg in the common carpusing the polyclonal rabbit anti-salmon Vtg antibody AA1 (Biosense, Norway); 2) check the sensitivity of carp juvenilesin producing Vtg in response to estrogen stimulation. The grouptreated with 17-estradiol showed high induction (156%)with respect to controls, also groups treated with 4-nonylphenolshowed induction of Vtg. The group treated with 100 mg kg^-1b.wt showed an induction of 61%. A statistically significantcorrelation was found between dose and response. This preliminary study demonstrate a response to the ELISA assay for Vtg in the common carp using rabbit anti-salmon antibody AA1. With further evidence the tested biomarker might be proposed for large scale monitoring of estrogenic effects caused by pollution in urban and industrial effluents.     

Partial neutralization of rain by seaspray: the case of Recôncavo, Bahia-Brazil

In the Recôncavo of Bahia (located between 12°33′ and 13°10′S and 38°00′and 39°00′W), there are significant discharges of SO₂ and NO_x due to local, industrial and urban activities. The incoming air masses from the Atlantic Ocean are enriched with seaspray, which neutralizes part of the rain acidity. The extent of seaspray neutralization of rain acidity was quantified in four sites of the region, each with different loads of seaspray. Rain samples were obtained daily at the same time, integrating the precipitation of the previous 24 h, using wet-only collectors and analyzed for pH by potentiometry and for sodium by flame photometry. The amount of rain acidity in Recôncavo neutralized by seaspray ranged from <1% up to 88% and depended on the site. On average, neutralization ranged from 5% to 18%.