Ecosystem processes: litter breakdown patterns in Mediterranean and Black Sea transitional waters

1 - Leaf litter decomposition rates, in aquatic ecosystems, are known to be related to many different abiotic and biotic factors. 2 - Here, we focus on the influence of abiotic factors, searching for patterns of reed litter decay rates on gradient of physiographic, hydrological and physico-chemical components of transitional water ecosystems. 3 - Field experiments were carried out in 16 water ecosystems in the Eastern Mediterranean and Black Sea in spring 2005. 4 - Significant differences of leaf litter decomposition were observed among ecosystems along univariate gradient of tidal range, index of sinuosity, water temperature and salinity. At least 71% of variance in the litter breakdown rate was explained by the considered abiotic factors. 5 - It is concluded that, at the macro-ecological scale of study, some key abiotic factors, such as tidal range and salinity, are suggested to play a major role as drivers of plant detritus decomposition processes. 6 - The relevance of the described abiotic drivers as descriptor of the most commonly used classification schemes for transitional water ecosystems (i.e., Confinement and Venice System classifications), is a further support to their role as environmental forcing factors

The relationship between resting energy expenditure and thyroid hormones in response to short-term weight loss in severe obesity

Background Regulating thermogenesis is a major task of thyroid hormones (THs), and involves THresponsive energetic processes at the central and peripheral level. In severe obesity, little is known on the relationship between THs and resting energy expenditure (REE) before and after weight loss. Methods We enrolled 100 euthyroid subjects with severe obesity who were equally distributed between genders. Each was examined before and after completion of a 4-wk inpatient multidisciplinary dieting program and subjected to measurement of thyroid function, REE, fatfree mass (FFM, kg) and percent fat mass (FM). Results Baseline REE was lower than predicted in 70 obese patients, and overall associated with BMI, FFM and FM but not thyroid-related parameters. By the study end, both BMI and REE decreased (5.5% and 4.1%, p<0.001 vs. baseline) and their percent changes were significantly associated (p<0.05), while no association related percent changes of REE and FFM or FM. Individually, REE decreased in 66 and increased in 34 patients irrespective of gender, BMI and body composition. Weight loss significantly impacted TSH (-6.3%), FT3 (-3.3%) and FT4 levels (3.9%; p<0.001 for all). By the study end, a significant correlation became evident between REE and FT4 (r = 0.42, p<0.001) as well as FT3 (r = 0.24, p<0.05). In stepwise multivariable regression analysis, however, neither THs nor body composition entered the regression equation for REE response to weight loss. Conclusions In severe obesity, short-term weight loss discloses a positive relationship between REE and THs

Rabphilin 3A: A novel target for the treatment of levodopa-induced dyskinesias

N-methyl-d-aspartate receptor (NMDAR) subunit composition strictly commands receptor function and pharmacological responses. Changes in NMDAR subunit composition have been documented in brain disorders such as Parkinson's disease (PD) and levodopa (L-DOPA)-induced dyskinesias (LIDs), where an increase of NMDAR GluN2A/GluN2B subunit ratio at striatal synapses has been observed. A therapeutic approach aimed at rebalancing NMDAR synaptic composition represents a valuable strategy for PD and LIDs. To this, the comprehension of the molecular mechanisms regulating the synaptic localization of different NMDAR subtypes is required. We have recently demonstrated that Rabphilin 3A (Rph3A) is a new binding partner of NMDARs containing the GluN2A subunit and that it plays a crucial function in the synaptic stabilization of these receptors. Considering that protein-protein interactions govern the synaptic retention of NMDARs, the purpose of this work was to analyse the role of Rph3A and Rph3A/NMDAR complex in PD and LIDs, and to modulate Rph3A/GluN2A interaction to counteract the aberrant motor behaviour associated to chronic L-DOPA administration. Thus, an array of biochemical, immunohistochemical and pharmacological tools together with electron microscopy were applied in this study. Here we found that Rph3A is localized at the striatal postsynaptic density where it interacts with GluN2A. Notably, Rph3A expression at the synapse and its interaction with GluN2A-containing NMDARs were increased in parkinsonian rats displaying a dyskinetic profile. Acute treatment of dyskinetic animals with a cell-permeable peptide able to interfere with Rph3A/GluN2A binding significantly reduced their abnormal motor behaviour. Altogether, our findings indicate that Rph3A activity is linked to the aberrant synaptic localization of GluN2A-expressing NMDARs characterizing LIDs. Thus, we suggest that Rph3A/GluN2A complex could represent an innovative therapeutic target for those pathological conditions where NMDAR composition is significantly altered

Sonographic assessment of abdominal fat distribution in infancy

There is growing evidence that not only the total amount of fat, but also the distribution of body fat determines risks for metabolic and cardiovascular disease. Developmental studies on factors influencing body fat distribution have been hampered by a lack of appropriate techniques for measuring intraabdominal fat in early life. Sonography, which is an established method for assessing abdominal fat distribution in adults, has not yet been evaluated in infants. To adapt the sonographic measurement of abdominal fat distribution to infants and study its reliability. The Generation R study, a population-based prospective cohort study. We included 212 one- and 227 two-year old Dutch infants in the present analysis. Sixty-two infants underwent replicate measurements to assess reproducibility. We developed a standardized protocol to measure the thickness of (1) subcutaneous and (2) preperitoneal fat in the upper abdomen of infants. To this end we defined infancy specific measurement areas to quantify fat thickness. Reproducibility of fat measurements was good to excellent with intraclass correlation coefficients of 0.93–0.97 for intra-observer agreement and of 0.89–0.95 for inter-observer agreement. We observed a pronounced increase in preperitoneal fat thickness in the second year of life while subcutaneous fat thickness increased only slightly, resulting in an altered body fat distribution. Gender did not significantly influence fat distribution in the first two years of life. Our age specific protocol for the sonographic measurement of central subcutaneous and preperitoneal fat is a reproducible method that can be instrumental for investigating fat distribution in early life

Influence of the water treatment on the xylem anatomy and functionality of current year shoots of olive tree.

6 páginas, 3 figuras, 1 tabla, 19 referencias.-- XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on CLIMWATER 2010: Horticultural Use of Water in a Changing Climate. Lisboa, Portugal.From May to October 2006 we applied two water treatments in an olive orchard in south Spain with 38-year-old "`Manzanilla" trees at 7×5 m spacing: a) rainfed, with rainfall as the only source of water supply; b) FAO, in which the trees were drip-irrigated daily from May to September, to replace the crop water needs. The aim of this work was to evaluate the influence of the water treatments on both the anatomical characteristics and the hydraulic performance of the xylem of current-year shoots. In November, 3 cm long segments were taken at 5 cm from the base of current-year shoots of each treatment. Part of these samples was used for hydraulic conductivity (Kh, g m MPa-1 s-1) measurements with a hydraulic conductivity meter designed and built in our group. The rest was cryo-fixed in liquid nitrogen for observation by cryo-scanning electron microscopy (cryo-SEM), which allowed us to determine vessel density (vessels mm-2) and vessel distribution per diameter classes, at 2 µm diameter intervals. The xylem water potential (¿xylem) of each sample was also measured, at shoot sampling. The anatomical analysis showed no differences between treatments in vessel density. From the amount of vessel, rainfed trees showed narrower vessels than FAO trees. This may explain the lack of differences in Kh found between the two studied treatments. In fact, the incidence of cavitation is smaller in vessels of reduced diameter. In addition, any reduction in diameter implies a reduced collective pit area between vessels, which reduces the incidence of embolism due to air-seeding. Therefore, the greater number of vessels with reduced diameter induced by the greater water stress suffered by the rainfed trees may have been the major reason for maintaining similar hydraulic conductivities in those trees than in drip-irrigated olive trees.This work has been funded by the research project CICYT/FEDER AGL2004- 0794-CO3-02/AGR, and by the IFAPA, Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía, research project ref. CO3-056.Peer Reviewe

Cannabinoid receptor gene detection by electrochemical genosensor

This paper describes the investigation of two aspects which play a fundamental role in the development of an enzyme-linked electrochemical genosensor: the labelling step and the electrode surface. Biotinylated locked nucleic acid (LNA) signalling probes were investigated in order to design a sandwich hybridisation format able to detect PCR amplified samples with high specificity. After labelling the biotinylated hybrid with a streptavidin-enzyme conjugate, the electrochemical detection of the enzymatic product was performed onto the surface of disposable carbon nanotube-modified electrode. In this way, the sensor coupled the high stability and specificity of LNA with the unique electrical properties of carbon nanotubes (high surface area, fast heterogeneous electron transfer, chemical stability, and ease of miniaturisation). After characterisation, the sensor was applied to the detection of PCR amplicons related to a region of the CB2 cannabinoid receptor gene (CNR2), which is relevant for the study of a mutation suspected to account for altered receptor activity. To our knowledge, this is the first example of recognition of this particular gene in real samples, using a LNA-based electrochemical genosensor. A linear response was obtained over a wide concentration range (0-100 nmol/L) and a detection limit of 0.4 nmol/L was achieved (RDS = 9%)