Ecosystem Services and Economic Assessment of Land Uses in Urban and Periurban Areas

Environmental Management - This work quantified ecosystem services (ES) and the geographic gross product (GGP) at municipal level in the Metropolitan Region of Buenos Aires (MRBA), Argentina. The...     

New contributions to the study of common double mutants in the human <Emphasis Type="Italic">LDL</Emphasis> receptor gene

Variations in the gene encoding the low-density lipoprotein receptor (LDLR) can cause familial hypercholesterolemia (FH), one of the most common inherited metabolic disorders in humans. The functional effects of the p.Gln92Glu and p.Asn564His alterations are predicted as benign, but the c.313 + 1G>C and p.Lys799_Phe801del changes are believed to cause disease. Although p.Gln92Glu and c.313 + 1G>C have been observed only in Spain, p.Asn564His and p.Lys799_Phe801del are widespread in Western Europe. In order to estimate the ages (t generations) of these four variants of the gene, to determine their possible origin and to consider the influence of age and selective pressure on their spread, we analyzed 86 healthy individuals and 126 FH patients in Spain. Most of the FH patients investigated carried two of these four LDLR variants simultaneously, while only one patient carried three of them simultaneously. Haplotype analyses were based on five LDLR SNPs: c.81T>C, c.1413G>A, c.1725C>T, c.1959T>C and c.2232G>A. The results suggest that p.Gln92Glu and c.313 + 1G>C arose at about the same time (99 and 103 generations ago, respectively) in the CACTG haplotype and that p.Asn564His and p.Lys799_Phe801del appeared in the CGCCG haplotype and might be slightly more recent variations (92 and 95 generations ago, respectively). Low selective pressures could explain the maintenance of these variants in spite of their ages. The origin of p.Gln92Glu and c.313 + 1G>C appears to be in Spain whereas p.Asn564His and p.Lys799_Phe801del could have been introduced in Spain by Celtic migrations in the seventh to fifth centuries BC.     

Nitrate losses, nutrients and heavy metal accumulation from substrates assembled for urban soils reconstruction

Urban soils may suffer mild to severe degradation as a result of physical and chemical alterations. To reconstruct these soils, a new upper horizon must be created, usually through the application of organic matter, one source of which is biosolids. Different soil mixtures were evaluated with regard to loss of nitrates in percolates and the uptake and incorporation of nutrients and heavy metals into plant tissues. The experiment was conducted in trays; treatments were mixtures of biosolids and a coarse material (e.g., sand or pine wood sawdust), combined in different proportions. Randomized trays were seeded with a mix of tall fescue (Festuca arundinacea L.) and perennial ryegrass (Lolium perenne L.). Plant biomass was quantified. Nitrates in percolates were measured, as were nutrients and heavy metals in mixtures and plant tissues. Plants accumulated substantially more N, and biomass was 40% higher, in the treatments with higher levels of biosolids. The same treatments released more nitrogen and resulted in higher percolate nitrate levels. Plants had normal concentrations of all nutrients, except nitrogen, which was low. Heavy metal concentrations were not significantly different among treatments. Based on the analysis of these data, the proportion of biosolids appears to be the most important factor affecting the quality of reconstructed soil and the rate of improvement. The type of coarse material used did not significantly affect the outcome.