Synthesis of o,p-EDDHA and its detection as the main impurity in o,o-EDDHA commercial iron chelates

Ethylenediamine-N,N'bis(o-hydroxyphenyl)acetic acid (o,o-EDDHA) is one of the most efficient iron chelates employed to relieve iron chlorosis in plants. However, the presence of positional isomers of EDDHA in commercial iron chelates has been recently demonstrated, and among them, it has been claimed that ethylenediamine-N(o-hydroxyphenylacetic)-N'(p-hydroxyphenylacetic) acid (o,p-EDDHA) is the main impurity present in EDDHA fertilizers. Here we report the preparation of o,p-EDDHA, a compound whose synthesis had not been previously reported. The synthetic o,p-EDDHA is able to form ferric complexes, and it has been used as a standard in the analysis of the impurities of commercial iron fertilizers. The presence of o,p-EDDHA/Fe(3+) in commercial samples has been unambiguously demonstrated by HPLC.     

Genetic variation and demographic contraction of the remnant populations of Mexican Caribbean pine (<Emphasis Type="Italic">Pinus caribaea</Emphasis> var. <Emphasis Type="Italic">hondurensis</Emphasis>: Pinaceae)

• Introduction   

The recognition of endangered species takes into account geographic isolation and small size of populations, as is the case of two populations of Pinus caribaea var. hondurensis distributed in México.     

Increased apoptosis of CD4 and CD8 T lymphocytes in the airways of horses with recurrent airway obstruction

Recurrent airway obstruction (RAO, also known as equine heaves) is an inflammatory condition similar to human asthma caused by exposure of susceptible horses to poorly ventilated stable environments. The disease is characterized by neutrophilic airway inflammation, mucus hypersecretion and reversible bronchoconstriction. This inflammatory process is mediated by several factors, including antibodies, cytokines, resident cells of the airway and inflammatory cellular components that arrive in the respiratory tract. An increasing body of evidence has lent support to the concept that a dysregulation of T cell apoptosis may play a central role in the development of airway inflammation and the associated asthma. Therefore, the aim of this study was to investigate early and late apoptosis of CD4 and CD8 T cell subpopulations obtained from the airways of acute RAO-positive animals after exposure to hay/straw. The percentages of CD4 and CD8 T cells and their associated frequencies of apoptosis were quantified using flow cytometry. Hay/straw exposure induced clinical airway obstruction, airway neutrophilia and increased airway mucus production in RAO-positive horses. In addition, allergen exposure increased the percentage of CD4 T cells in RAO-positive horses as well as the frequency of early and late apoptosis in both CD4 and CD8 lymphocyte subpopulations. These results suggest that the higher frequency of lymphocyte apoptosis may play a role in disease progression of horses afflicted with RAO and may partially explain the characteristic remission of this pathological condition once the allergen source is removed. However, further studies are needed to clarify the role of T cell apoptosis in RAO-affected horses.     

Soil Contamination in Dumps on the Karstic Areas from the Plateaus (Southeast of Madrid, Spain)

After over 10 years of accumulation of residues in the studied dumps near Madrid, it has been registered low or moderate heavy metals concentrations on the surrounding area. Only occasionally, some rubbish dumps contain significant quantities of Cu, Ni, Zn and Pb. The concentration levels of Pb, Ni, Zn and Cu are safe when they are compared with the surrounding areas levels of heavy metals. The aim of this paper is the analysis of pollutants existing around in the dumps located at the sides of the plateaus of the central valley of the Tajo River (provinces of Madrid and Toledo, Spain). The high karstification rate of the upper layer of these tablelands and the existence of numerous dumps on them (even on their slopes) make these areas vulnerable to heavy metal pollution. However, after several years of use, the concentration of pollutants only reaches moderate values in the studied areas. Dumping materials were collected at four rubbish dumps. The mineralogical composition of the materials were analysed by XRD. Sequential extraction procedure was applied for speciation of the metal forms in the collected samples. Concentrations of Zn, Pb, Ni, Cu, Cr and Cd in extracts were determined by AAS. The studied samples showed high carbonate concentration. Contamination processes are combined there with weathering processes. Heavy metals concentration in control samples (gypsum, limestones, red soils and colluviums) were compared with samples of the studied dump in order to evaluate the pollution level. Concentrations of Zn, Pb, Ni and Cu were variable. The contamination was elevated for samples in depth in relation with weathering process of heavy metals.     

Comparison of In Vitro PBET and Phosphoric Acid Extraction as an Approach to Estimate Selenite and Selenate Bioaccessibility from Soil

Several approaches have been used to estimate the bioaccessibility of trace metals from soils. Here, we applied phosphoric acid extraction and the in vitro test physiologically based extraction (PBET) to soils containing selenium (Se) and compared their performance in estimating the bioaccessibility of Se. For this purpose, we used two soil samples and two Certified Reference Material soil samples with a range of Se concentrations. The total Se contents were measured in the samples and in the extracts by hydride generation–atomic fluorescence spectroscopy. Moreover, we also measured selenite and selenate in the soil extracts (from phosphoric acid and from the PBET) using the coupled techniques liquid chromatography–UV photooxidation–atomic fluorescence spectroscopy and liquid chromatography–mass spectrometry with inductively coupled plasma. From the results obtained in the present study, the PBET showed that the selenium bioaccessible fraction was mainly attributed to the gastrointestinal step. When comparing the results from PBET with those of the phosphoric acid extraction, similar values of Se (IV) and Se (VI) were obtained for both extraction systems. An estimation of the bioaccessibility percentage of Se is also reported.     

Changes in fruit maturity indices along the harvest season in ‘Algerie’ loquat

Loquat is a subtropical fruit tree that presents an annual cycle reverse to that of the well-known temperate fruit crops. Loquat rests during summer, blooms in autumn, develops its fruit through winter and ripens them in early spring. Its unusual phenology allows growers to obtain high prices for its fruits, especially for early harvests. Although loquat is harvested based on skin colour, a minimum soluble solid content (TSS) of 10° Brix is often required for commercialization. However, we have noticed that the relationship between skin colour and eating quality seems to change along the season leading costumers to complain for the high acidity of the earliest fruits. In order to establish a reliable maturity index, we have evaluated the changes in different fruit maturation parameters along the harvest period in four consecutive seasons for ‘Algerie’ loquat. The results show that in samples collected with similar skin colour, TSS and, especially, fruit titratable acidity (TA) tend to decline as harvest season progresses. This makes fruit skin colour on its own not suitable as a harvest index to assure an adequate fruit quality under all circumstances. We propose instead to monitor continuously TSS and TSS/TA ratio along the season in order to fulfill consumer's expectations.     

The land use–climate change–energy nexus

Landscape ecology focuses on the spatial patterns and processes of ecological and human interactions. These patterns and processes are being altered by both changing resource-management practices of humans and changing climate conditions associated, in part, with increases in atmospheric concentrations of greenhouse gases. Dominant resource-extraction and land-management activities involve energy, and the use of fossil energy is one of the key drivers behind increasing greenhouse gas emissions as well as land-use changes. Alternative energy sources (such as wind, solar, nuclear, and bioenergy) are being explored to reduce greenhouse gas emission rates. Yet, energy production, including alternative-energy options, can have a wide range of effects on land productivity, surface cover, albedo, and other factors that affect carbon, water, and energy fluxes and, in turn, climate. Meanwhile, climate influences the potential output, relative efficiencies, and sustainability of alternative energy sources. Thus, land use, climate change, and energy choices are linked, and any comprehensive analysis in landscape ecology that considers one of these factors should be cognizant of these interactions. This analysis explores the implications of linkages between land use, climate hange, and energy and points out ecological patterns and processes that may be affected by their interactions.