Translocation of soils to simulate climate change: CO2 emissions and modifications to soil organic matter.

The effect of climate change on CO2 emissions was studied on undisturbed soil monoliths (40-cm diameter, 25-cm high), which were translocated to warmer zones than their place of origin. Thirty-two months after the translocation, a climatic factor deduced from the moisture content of the soil and from the effective mean temperature (temperatures in excess of 5 ºC) revealed that translocation increased the potential of the climate to enhance the biological processes by between 73% and 26% compared with what the soil would support in its place of origin. At the end of the study, the transported soils had lost a large proportion of both total carbon and nitrogen (between 20 and 45%). During the experiment, the CO2 emissions from the soils, measured under field conditions, were quite variable, but were usually greater than from soils in situ. The variation in labile C in the soil throughout the experiment was calculated from a first-order kinetic equation for organic matter decay. The relative CO2 emissions, expressed in terms of the labile carbon fraction in the soils, were clearly greater in those translocated soils that underwent the most intensive climate change, which indicates that the variations in emissions over time are basically a function of the size of the labile organic matter pool.Peer reviewe

Evaluation of various tests for the diagnosis of soil contamination by 2,4,5 trichlorophenol (2,4,5-TCP).

The response of different types of soils to contamination with 2,4,5-triclorophenol was studied to test the validity of the concept of generic reference levels (GRL), the main criterion used to define soil contamination. Soil samples were artificially contaminated with doses of between 0 and 5000 mg kg-1of 2,4,5-triclorophenol, and analysed by various tests. Where possible, the response of soils to the contaminant was modelled by a sigmoidal dose-response curve in order to estimate the ED50 values. The tests provided different responses, but only microbial biomass-C and dehydrogenase and urease activities demonstrated soil deterioration in response to contamination. The results suggest that the diagnosis of soil contamination has been greatly simplified in the legislation by the provision of a single figure for each compound, and that the GRL concept could perhaps be substituted by measurement of ED50 values, which better reflect the alteration of a soil due to the presence of a xenobiotic substance.Peer reviewe

Modification of enzymatic activity in soils of contrasting pH contaminated with 2,4-dichlorophenol and 2,4,5-trichlorophenol.

According to previous studies, acidic soils may receive larger quantities of 2,4-dichlorophenol (2,4-DCP) and of 2,4,5-trichlorophenol (2,4,5-TCP) than the concentrations indicated in the prevailing legislation for defining a soil as contaminated, without any important changes in their biochemical properties. In this study, we investigated whether neutral or slightly alkaline soils behave in the same way as acidic soils in response to contamination by these compounds. For this purpose, a large number of acidic soils (pH between 4.2 and 5.9) and calcareous soils (pH between 6.5 and 8.0 ) were contaminated in the laboratory with different doses of 2,4-DCP (up to 10000 times the GRL) and of 2,4,5-TCP (up to 500 times the GRL). After an incubation period of three days, the activities of several enzymes (dehydrogenase, catalase, ß-glucosidase and phosphomonoesterase) were measured in the soils. The effects of 2,4,5-TCP were much greater than those of 2,4-DCP in both the acidic and calcareous soils, regardless of the dose applied. Phosphomonoesterase and ß-glucosidase activities were scarcely affected by either of the contaminants in any of the soils, whereas the catalase activity decreased slightly. The dehydrogenase and urease activities were strongly affected in all soils and in some cases even disappeared, particularly after the application of 2,4,5-TCP. Multiple regression analysis of the percentage reductions in dehydrogenase and urease activities in relation to contaminant dose and different soil properties indicated that the reduction in enzyme activity depended, in decreasing order, on the dose of contaminant applied, total carbon content and soil pH. We suggest that the processes that regulate the toxicity of these compounds in soils are their adsorption by soil organic matter and the dissociation of the non-adsorbed compound into phenolate ions (which are toxic to microorganisms). In fact, the chlorophenols scarcely affected the biochemical properties of the soils under study because of their high organic matter contents (A horizons with total carbon contents of up to 11%). Moreover, both chlorophenols had slightly stronger effects on the calcareous soils than on the acidic soils, probably because the dissociation process was favoured at higher pH. On the other hand, the 2,4,5-TCP had stronger effects on soil biochemical properties than 2,4-DCP, which may be explained by the lower pKa value of 2,4,5- 2 TCP (6.9) than that of 2,4-DCP (7.9). The results show that the GRL values established by the legislation are not appropriate for either of these chlorophenol compounds.Peer reviewe

Labile carbon in biological soil crusts in the Tabernas desert, SE Spain.

Decomposition processes are extremely important in biological soil crusts (BSCs). Although the effects of temperature and moisture on such processes have been widely studied, little is known about the influence of the readily metabolizable substrate (labile C) and how this substrate varies in different types of BSCs. In the present study, BSCs formed by cyanobacteria (CYANO) and by lichens (DIPLOS and LEPRA) were incubated at 25 °C (optimum temperature) and different moisture levels, for evaluation of the pool of labile C in the crust layers. Labile C was estimated as the sum of CO2-C emitted and the C extracted with hot water (80 °C) at the end of the incubation period. In all crusts, the relationship between emission and moisture fitted a quadratic model. For the different moisture contents, the sum of CO2-C emitted and C extracted with hot water converged to a constant value for each type of crust. This value, considered as the maximum content of labile C in the crust, was extremely high in DIPLOS, reaching up to 40% of the total organic C (TOC) initially present. In all crusts, and independently of the consumption of labile C, simple sugars (sucrose, glucose) remained at the end of the incubation period, which suggests that these sugars may play a protective role in BSCs. The presence of mannitol suggests that the fructose released during hydrolysis of sucrose was reduced to mannitol, thus enabling electron transport during moments of intense respiratory stress. The intense respiration in DIPLOS is partly due to the metabolism of polyphenols, which are possibly derived from the growth and death of free-living fungi that proliferate during incubation of the crusts. These results demonstrate that the metabolic processes in BSCs differ depending on the type of organisms that form the crusts and that there is a high risk of C loss from Diploschistes BSCs after heavy rainfall events.Peer reviewe

Associations Between Body Composition and Movements During Gait in Women.

El objetivo de este trabajo es explorar las relaciones entre los parámetros acelerométricos de la marcha y la composición corporal en mujeres sanas. Para conseguirlo se realice un estudio transversal con una muestra de 112 mujeres adultas sanas (64,1 ± 8,6 años). Las participantes caminaron una distancia de 20 metros con un acelerómetro triaxial situado a la altura de la cuarta vértebra lumbar. La prueba se repitió tres veces y se utilizó la media de los tres ensayos para el análisis. También se evaluaron indicadores clínicos (Timed Up and Go Test, prueba de los seis minutos marcha y perímetro de cintura) y la composición corporal (bioimpedancia). Los porcentajes de grasa corporal total y en miembros inferiores se correlacionaron fuertemente con la aceleración media en eje vertical y el valor mínimo de módulo vector de las aceleraciones. En mujeres mayores de 71 años, la proporción de grasa corporal total y de miembros inferiores determina los movimientos del cuerpo durante la marcha. Por tanto, la cantidad de masa grasa está relacionada con la estabilidad en la marcha de las personas mayoresThe aim of this paper is to explore the relationships between gait parameters and body composition in healthy women. A cross-sectional study with a sample composed of 112 healthy adult women (64.1 ± 8.6 years). The subjects walked a distance of 20 meters with a triaxial accelerometer attached at the fourth lumbar vertebra. The test was repeated three times and the mean of the three trials was used for the analysis. Clinical indicators (Timed Up and Go Test, 6-Minute Walk Test and waist perimeter) and body composition (bioimpedance) were also evaluated. Total body and lower limb fat mass percentages were strongly correlated with the average acceleration in vertical axis and the minimum value of module vector of the accelerations. In women over the age of 71, the percentage of total body fat and lower limbs determines body movements during gait. Therefore, the amount of fat mass is related to the stability in the gait of the elderl

Spongionella secondary metabolites protect mitochondrial function in cortical neurons against oxidative stress

Accepted: 8 January 2014 This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Acknowledgments The research leading to these results has received funding from the following FEDER cofunded-grants: From Ministerio de Ciencia y Tecnología, Spain: AGL2009-13581-CO2-01, AGL2012-40485-CO2-01. From Xunta de Galicia, Spain: 10PXIB261254 PR. From the European Union’s Seventh Framework Programme managed by REA—Research Executive Agency (FP7/2007–2013) under grant agreement Nos. 265896 BAMMBO, 265409 µAQUA, and 262649 BEADS, 315285 CIGUATOOLS and 312184 PHARMASEA. From the Atlantic Area Programme (Interreg IVB Trans-national): 2009-1/117 Pharmatlantic. MER thanks the Government of the Arab Republic of Egypt for a PhD Scholarship. MJ thanks the Scottish University Life Science Alliance which provided funding to set up the compound library.Peer reviewedPublisher PD

Hydrolase enzyme activities in a successional gradient of biological soil crusts in arid and semi-arid zones.

In arid and semi-arid regions, pioneer organisms form complex communities that penetrate the upper millimetres of the bare substrate, creating biological soil crusts (BSC). These thin crusts play a vital role in whole ecosystem functioning because they enrich bare surfaces with organic matter, initiate biogeochemical cycling of elements, modify hydrological cycles, etc., thus enabling the ground to be colonized by vascular plants. Various hydrolase enzymes involved in the carbon (cellulase, ß-glucosidase and invertase activities), nitrogen (casein-protease and BAA- protease activities) and phosphorus (alkaline phosphomonoesterase activity) cycles were studied at three levels (crust, middle and deep layers) of three types of BSCs from the Tabernas Desert (SE Spain), representing an ecological gradient ranging from crusts predominated by cyanobacteria to crusts predominated by lichens (Diploschistes diacapsis, Lepraria crassissima). All enzyme activities were higher in all layers of all BSCs than in the bare substrate. The enzymes that hydrolyze low molecular weight substrates were more active than those that hydrolyze high molecular weight substrates (cellulase, casein-protease), highlighting the pioneering characteristics of the BSCs. The hydrolytic capacity developed in parallel to that of ecological succession, and the BSCs in which enzyme activity was highest were those under Lepraria crassissima. The enzyme activity per unit of total organic C was extremely high; the highest values occurred in the BSCs formed by cyanobacteria and the lowest in those formed by lichens, which 2 indicates the fundamental role that the primary colonizers (cyanobacteria) play in enriching the geological substrate with enzymes that enable degradation of organic remains and the establishment of more developed BSCs. The results of the study combine information on different enzyme activities and provide a clear vision of how biogeochemical cycles are established in BSCs, thus confirming the usefulness of enzyme assays as key tools for examining the relationship between biodiversity and ecosystem function in biological soil crusts.Peer reviewe

Biological and microbial activity in biological soil crusts from the Tabernas desert, a sub-arid zone in SE Spain.

The ecology and functional role of biological soil crusts (BSCs) in arid and semi-arid zones have been extremely well studied. However, little is known about the biochemical properties related to the number and activity of the microbiota that form the crusts, even though information about these properties is very important for understanding many of the processes that affect the formations. In this study, several properties related to the activity and number of microorganisms (biomass-C, basal respiration, dehydrogenase activity and nitrogen mineralization potential) were determined at different depths (crusts, 0-0.5 cm; middle, 0.5-3 cm and deep, 3-5 cm layers) in two types of crusts (predominated by cyanobacteria and by lichens) in the Tabernas desert (Almeria, SE Spain). The absolute values of the above-mentioned properties and the values expressed relative to the total organic carbon (TOC) content were both much higher in the crust layers than in the surface horizons of soils under Mediterranean or Atlantic climates. A large part of the TOC in the BSCs was contained in the microbiota and another large part was readily metabolized during incubation of the crusts for 10 days at 25 °C. The net nitrogen mineralization rate was also high, and ammonification predominated in the crust layers, whereas nitrification predominated in the middle and deep layers. In all types of BSCs, the microbiota colonized the deep layers, although with greater intensity in the lichen-dominated BSCs than in the cyanobacterial BSCs. The results also indicate that hydrolytic enzymes are not stabilized on soil colloids and their activity depends only on the active microbiota.Peer reviewe

The endoplasmic reticulum protein HSPA5/BiP is essential for decidual transformation of human endometrial stromal cells

Decidualization denotes the process of inflammatory reprogramming of endometrial stromal cells (EnSC) into specialized decidual cells (DC). During this process, EnSC are subjected to endoplasmic reticulum (ER) stress as well as acute cellular senescence. Both processes contribute to the proinflammatory mid-luteal implantation window and their dysregulation has been implicated in reproductive failure. Here, we evaluated the link between ER stress, decidual differentiation and senescence. In-silico analysis identified HSPA5 gene, codifying the ER chaperone BiP, as a potentially critical regulator of cell fate divergence of decidualizing EnSC into anti-inflammatory DC and pro-inflammatory senescent decidual cells (snDC). Knockdown of HSPA5 in primary EnSC resulted both in decreased expression of DC marker genes and attenuated induction of senescence associated β-galactosidase activity, a marker of snDC. Stalling of the decidual reaction upon HSPA5 knockdown was apparent at 8 days of differentiation and was preceded by the upregulation of ER stress associated proteins IRE1α and PERK. Further, HSPA5 knockdown impaired colony-forming unit activity of primary EnSC, indicative of loss of cellular plasticity. Together, our results point to a key role for HSPA5/BiP in decidual transformation of EnSCs and highlight the importance of constraining ER stress levels during this process