Assessing estuarine quality under the ecosystem services scope: Ecological and socioeconomic aspects

An increasing need for integrative assessments that measure the contributions of the environment to human welfare has recently been recognised. In the present study, a preliminary assessment of the services provided by the Mondego Basin in terms of system ecological quality was carried out. The ecological, economic, and societal relations of the Mondego estuarine services were analysed. An inventory of the main ecosystem services provided by the Mondego system was performed. The conditions and trends of the main services (food production, recreation and water quality maintenance) were determined, and the scale dependence of this assessment was interpolated on three different scales: Mondego Basin, Lower Mondego, and Mondego Estuary. The interdependence among services was quantified; an ecological assessment regarding water quality and ecological conditions was performed, and a preliminary valuation of the food production, recreation and tourism in the region was undertaken. In the study system, from 1992 to 2006, there was an increase in recreation activities and water uses and a simultaneous decrease in services such as food production (i.e., strong interdependence among services). Ecological quality improvement is reflected in both local communities’ diversity and water quality. The market prices method was used to estimate the values for the three services considered; however, the Mondego catchment's full value cannot be calculated without estimating the real wetlands value because these are prone to underestimation. Uncertainties and shortcomings regarding the reliability of this kind of assessment for implementation on estuarine ecosystems are discussed.     

New dextrin-vinylacrylate hydrogel: Studies on protein diffusion and release

New dextrin hydrogels with degrees of substitution (DS) from ca. 10% (DS 10) to 70% (DS 70) were prepared by radical polymerization of aqueous solutions of vinylacrylate (VA)-derivatized dextrin. A preliminary analysis on the potential of these hydrogels for the controlled release of bioactive molecules was carried out. The protein (bovine serum albumin) diffusion coefficients on the hydrogels were calculated using the lag-time analysis. Values in range 10^?7 cm²/s were obtained for DS 20 and DS 40 and a smaller value of 10^?8 cm²/s arised upon DS increasing to 70%, revealing the dependence of the diffusivity on the crosslinking density. The release of BSA from dextrin-VA hydrogels, in the presence of amyloglucosidase was shown to be mainly dependent on the diffusion and, to a smaller extent, on the degradation kinetics. The protein release can be tailored from days to months by varying the DS.     

Laccase immobilization on enzymatically functionalized polyamide 6,6 fibres

Polyamide matrices, such as membranes, gels and non-wovens, have been applied as supports for enzyme immobilization, although in literature the enzyme immobilization on woven nylon matrices is rarely reported. In this work, a protocol for a Trametes hirsuta laccase immobilization using woven polyamide 6,6 (nylon) was developed. A 2⁴ full factorial design was used to study the influence of pH, spacer (1,6-hexanediamine), enzyme and crosslinker concentration on the efficiency of immobilization. The factors enzyme dosage and spacer seem to have played a critical role in the immobilization of laccase onto nylon support. Under optimized working conditions (29 U mL⁻¹ of laccase, 10% of glutaraldehyde, pH = 5.5, with the presence of the spacer), the half-life time attained was about 78 h (18% higher than that of free enzyme), the protein retention was 30% and the immobilization yield was 2%. The immobilized laccase has potential for application in the continuous decolourization of textile effluents, where it can be applied into a membrane reactor.     

Acclimation of photosynthesis and respiration is asynchronous in response to changes in temperature regardless of plant functional group

Gas exchange, fluorescence, western blot and chemical composition analyses were combined to assess if three functional groups (forbs, grasses and evergreen trees/shrubs) differed in acclimation of leaf respiration (R) and photosynthesis (A) to a range of growth temperatures (7, 14, 21 and 28 degrees C). When measured at a common temperature, acclimation was greater for R than for A and differed between leaves experiencing a 10-d change in growth temperature (PE) and leaves newly developed at each temperature (ND). As a result, the R : A ratio was temperature dependent, increasing in cold-acclimated plants. The balance was largely restored in ND leaves. Acclimation responses were similar among functional groups. Across the functional groups, cold acclimation was associated with increases in nonstructural carbohydrates and nitrogen. Cold acclimation of R was associated with an increase in abundance of alternative and/or cytochrome oxidases in a species-dependent manner. Cold acclimation of A was consistent with an initial decrease and subsequent recovery of thylakoid membrane proteins and increased abundance of proteins involved in the Calvin cycle. Overall, the results point to striking similarities in the extent and the biochemical underpinning of acclimation of R and A among contrasting functional groups differing in overall rates of metabolism, chemical composition and leaf structure.     

Intracellular signaling mechanisms mediating catecholamine release upon activation of NPY Y1 receptors in mouse chromaffin cells

The adrenal chromaffin cells synthesize and release catecholamine (mostly epinephrine and norepinephrine) and different peptides, such as the neuropeptide Y (NPY). NPY stimulates catecholamine release through NPY Y1 receptor in mouse chromaffin cells. The aim of our study was to determine the intracellular signaling events coupled to NPY Y1 receptor activation that lead to stimulation of catecholamine release from mouse chromaffin cells. The stimulatory effect of NPY mediated by NPY Y1 receptor activation was lost in the absence of extracellular Ca2+. On the other hand, inhibition of nitric oxide synthase and guanylyl cyclase also decreased the stimulatory effect of NPY. Moreover, catecholamine release stimulated by NPY or by the nitric oxide donor (NOC-18) was inhibited by mitogen-activated protein kinase (MAPK) and protein kinase C inhibitors. In summary, in mouse chromaffin cells, NPY evokes catecholamine release by the activation the NPY Y1 receptor, in a Ca2+-dependent manner, by activating mitogen-activated protein kinase and promoting nitric oxide production, which in turn regulates protein kinase C and guanylyl cyclase activation.     

Final height in patients with idiopathic short stature and high growth hormone responses to stimulation tests

Children with idiopathic short stature (ISS) may have normal or increased growth hormone (GH) responses to provocation tests and achieve a final height (FH) below -2.0 standard deviation score (SDS) if untreated. FH of subjects with high stimulated GH levels has not been studied in detail. AIM: It was the aim of this study to analyse FH in ISS patients with high GH peak responses to the provocation test. PATIENTS AND METHODS: We studied 16 patients (9 pre-pubertal) with ISS and a GH peak >or=40 mU/l to insulin-induced hypoglycaemia. The patients were recalled at age 19.7 +/- 2.5 years for measurement of FH when blood samples were obtained for serum insulin-like growth factor (IGF)-I, IGF binding protein 3, acid-labile subunit and GH binding protein measurements. GH bioactivity was determined using the Nb2 bioassay. RESULTS: FH was -3.1 +/- 1.0 SDS, being significantly lower than target height (TH). At FH, IGF-I levels were within -1.5 and +1.5 SDS for age and sex in 10 patients and higher than +1.5 SDS in 6 patients. IGF binding protein 3, acid-labile subunit, GH binding protein levels and GH bioactivity values were normal. SUMMARY: These data suggest that patients with ISS and high GH levels during a GH stimulation test may have a more compromised FH. The association of severe ISS with a peak GH >40 mU/l might suggest a degree of insensitivity for the GH-IGF-I axis.     

Viruses and dendritic cells: enemy mine

Dendritic cells (DCs) act not only as sentinels for detection of, but also as target cells for viruses, and this can be important for viral transport and spread. All subsets of DCs are equipped with a battery of receptors recognizing virus-associated molecular signatures, and recognition of those launches a maturation programme that results in substantial alterations of morphology, motility and the DCs' interactive properties with the extracellular matrix and scanning T cells. In addition to being sensed, viruses are internalized into DCs and, for the major proportion, processed into peptides that are subsequently presented by major histocompatibility complex (MHC) molecules. Transmission of virus to T cells can occur after completion of their replication cycle if the intracellular milieu of the DC permits that. Alternatively, viruses can remain protected from degradation following entrapment by pattern recognition receptors in intracellular compartments, also referred to as virosomes, which translocate towards the DC/T cell interface. Most likely, transfer of virus to T cells occurs in these junctions, referred to as infectious synapses. In addition to promoting DC maturation, many viruses are able to downmodulate DC development and functions in order to evade immune recognition or to induce a generalized immunosuppression.     

Eradication of rabbits from islets is essential for conservation of microinsular vegetation and narrow endangered flora: the case of Medicago citrina (Fabaceae) in s’Espartar islet (Balearic Islands,Western Mediterranean Basin)

Biodiversity and Conservation - The introduction of exotic herbivores to islands is one of the most harmful challenges to the conservation of insular biodiversity, causing the extinction or...     

Cape mountain zebra in the Baviaanskloof Nature Reserve,South Africa: resource use reveals limitations to zebra performance in a dystrophic mountainous ecosystem

Resource use of Cape mountain zebra was studied in the Baviaanskloof Nature Reserve (BNR) over concerns of the poor performance in population growth. We assessed the seasonal diet, habitat suitability and forage quality of the Bergplaas area in BNR for mountain zebra. Grasses contributed 95.2% to the annual diet of mountain zebra, Tristachya leucothrix contributing the most (39.4%), followed by Themeda triandra (27.6%). Seasonally, T. triandra contributed most to the diet in winter, while T. leucothrix became more important in the summer and also was the only species preferred in all seasons. Mountain zebra concentrated their feeding in Kouga Grassy Fynbos and from our assessment this was the only habitat suitable for mountain zebra. Our analysis of mountain zebra dung indicated that the seasonal nitrogen and phosphorus content was below the threshold values prescribed for grazers, and our study suggests that mountain zebra at Bergplaas are severely resource limited. We emphasize the importance of fire and access to nutrient‐rich lowlands in influencing the nutritional ecology of mountain zebra and provide conservation management recommendations.