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.     

Have the cake and eat it: Optimizing nondestructive DNA metabarcoding of macroinvertebrate samples for freshwater biomonitoring

DNA metabarcoding can contribute to improving cost‐effectiveness and accuracy of biological assessments of aquatic ecosystems, but significant optimization and standardization efforts are still required to mainstream its application into biomonitoring programmes. In assessments based on freshwater macroinvertebrates, a key challenge is that DNA is often extracted from cleaned, sorted and homogenized bulk samples, which is time‐consuming and may be incompatible with sample preservation requirements of regulatory agencies. Here, we optimize and evaluate metabarcoding procedures based on DNA recovered from 96% ethanol used to preserve field samples and thus including potential PCR inhibitors and nontarget organisms. We sampled macroinvertebrates at five sites and subsampled the preservative ethanol at 1 to 14 days thereafter. DNA was extracted using column‐based enzymatic (TISSUE) or mechanic (SOIL) protocols, or with a new magnetic‐based enzymatic protocol (BEAD), and a 313‐bp COI fragment was amplified. Metabarcoding detected at least 200 macroinvertebrate taxa, including most taxa detected through morphology and for which there was a reference barcode. Better results were obtained with BEAD than SOIL or TISSUE, and with subsamples taken 7–14 than 1–7 days after sampling, in terms of DNA concentration and integrity, taxa diversity and matching between metabarcoding and morphology. Most variation in community composition was explained by differences among sites, with small but significant contributions of subsampling day and extraction method, and negligible contributions of extraction and PCR replication. Our methods enhance reliability of preservative ethanol as a potential source of DNA for macroinvertebrate metabarcoding, with a strong potential application in freshwater biomonitoring.     

Carbon and Water Footprints and Energy Use of Greenhouse Tomato Production in Northern Italy

This study reports on the carbon, water, and energy footprints of tomatoes grown in a greenhouse in Northern Italy and two possible future variations of heating and carbon dioxide (CO₂) fertilization on the current setup. The heat supply in place, consisting of natural gas (NG) and canola oil combustion, is compared to cogeneration and incineration of municipal solid waste for heating and CO₂ from industrial exhaust for fertilization. As a benchmark, the current system is also compared to a conventional system, in which heat is delivered solely based on NG. Each kilogram (kg) of fresh tomatoes (“Cuore di Bue” variety) produced in the current greenhouse emits 2.28 kg CO₂ equivalents (eq) and uses 95.5 megajoules (MJ) eq energy and 122 liters (L) of water. Relative to the system in place, the carbon footprint (CF) is 57.5% and 18% higher with conventional NG heating and cogeneration and is 40% lower with waste valorization. Further, 33%, 55%, and 63% less energy and 9%, 96%, and 14% less water are used in the conventional, cogeneration, and waste valorization scenarios, respectively. This confirms that there are multiple strategies to reduce the impact of the tomato production under consideration.     

Successional patterns of key genes and processes involved in the microbial nitrogen cycle in a salt marsh chronosequence

Here, we investigated the patterns of microbial nitrogen cycling communities along a chronosequence of soil development in a salt marsh. The focus was on the abundance and structure of genes involved in N fixation (nifH), bacterial and archaeal ammonium oxidation (amoA; AOB and AOA), and the abundances of genes involved in denitrification (nirS, nirK, nosZ). Potential nitrification and denitrification activities were also measured, and increases in nitrification were found in soils towards the end of succession, whereas denitrification became maximal in soils at the intermediate stages. The nifH, nirK and nirS gene markers revealed increases in the sizes of the respective functional groups towards the intermediate stage (35 years), remaining either constant (for nifH) or slightly declining towards the latest stage of succession (for nirK and nirS). Moreover, whereas the AOB abundance peaked in soils at the intermediate stage, that of AOA increased linearly along the chronosequence. The abundance of nosZ was roughly constant, with no significant regression. The drivers of changes in abundance and structure were identified using path analysis; whereas the ammonia oxidizers (AOA and AOB) showed patterns that followed mainly N availability, those of the nitrogen fixers followed plant diversity and soil structure. The patterns of denitrifiers were group-dependent, following the patterns of plant diversity (nirK and nirS) and belowground shifts (nosZ). The variation observed for the microbial groups associated with the same function highlights their differential contribution at different stages of soil development, revealing an interplay of changes in terms of niche complementarity and adaptation to the local environment.     

Intermodal transfer from a visual to an auditory discrimination using an errorless learning procedure

Errorless learning is a technique developed by Terrace [Terrace, H.S., 1963a. Discrimination training with and without “errors”. J. Exp. Anal. Behav. 6, 1-27] to train stimulus discriminations with few or no errors. In the first replication of the original findings, errorless learning was also shown to transfer successfully between two visual discriminations without errors [Terrace, H.S., 1963b. Errorless transfer of a discrimination across two continua. J. Exp. Anal. Behav. 6, 223-232]. In the present experiment, we extended the errorless learning procedure to an intermodal transfer, from a discrimination between red and green colors to a discrimination between high and low tones. The pigeons were divided into two groups: an Experimental Group, which learned both discriminations through errorless learning, and a Control Group, which learned them through trial-and-error. Results showed that pigeons from the Experimental Group learned the red-green discrimination with significantly fewer errors than the Control Group and that errorless learning is effective in transferring from a visual to an auditory discrimination.     

Biomonitoring of a population of Portuguese workers exposed to lead

Lead is a heavy metal that has been used for many centuries and it is still used for various industrial purposes thanks to its physical and chemical characteristics. Human exposure to lead can result in a wide range of biological effects depending upon the level and duration of exposure. Despite the fact that lead has been found capable of eliciting genotoxic responses in a wide range of tests, not all studies have been conclusive. Although several experimental studies have shown that lead may modulate immune responses, data in exposed humans are still preliminary. The purpose of our study was to evaluate the genotoxic and immunotoxic effects of lead exposure in a group of 70 male workers from two Portuguese factories. The control group comprised 38 healthy males. The exposed individuals showed significantly higher levels of lead in blood and zinc protoporphyrin, and significantly lower δ-aminolevulinic acid dehydratase activity than the controls, suggesting a relatively high lead exposure. Nevertheless, the limit of 70 μg/dl for lead in blood established by the Portuguese regulation was never reached. Results of the comet assay were not modified by the exposure, but a significant increase in the mutation frequency in the exposed workers was obtained in the T-cell receptor mutation assay. Furthermore, data obtained in the analysis of the different lymphocyte subsets showed a significant decrease in %CD8+ cells and a significant increase in the %CD4+/%CD8+ ratio in exposed individuals with regard to the controls. No clear effect was observed for vitamin D receptor genetic polymorphism on the parameters evaluated. In view of our results showing mutagenic and immunotoxic effects related to lead exposure in occupational settings, it seems that the Portuguese biological exposure limit for lead needs to be revised in order to increase the safety of exposed workers.     

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.