New liquid supports in the development of integrated platforms for the reuse of oxidative enzymes and polydopamine production.

Polydopamine (PDA), a bioinspired polymer from mussel adhesive proteins, has attracted impressive attention as a novel coating for (nano) materials with an adequate conformal layer and adjustable thickness. Currently, PDA is obtained from dopamine chemical oxidation under alkaline conditions, limiting its use in materials sensible to alkaline environments. Envisaging a widespread use of PDA, the polymerization of dopamine by enzymatic catalysis allows the dopamine polymerization in a large range of pHs, overcoming thus the limitations of conventional chemical oxidation. Moreover, the conventional method of polymerization is a time-consuming process and produces PDA films with poor stability, which restricts its applications. On the other hand, the main bottleneck of enzyme-based biocatalytic processes is the high cost of the single use of the enzyme. In this work, laccase was used to catalyse dopamine polymerization. To improve its performance, a liquid support for integrating the laccase and its reuse together with the PDA production and recovery was developed using aqueous biphasic systems (ABS). Firstly, dopamine polymerization by laccase was optimized in terms of pH, temperature and initial dopamine concentration. It was demonstrated that the highest enzymatic polymerization of dopamine was achieved at pH 5.5, 30°C and 2 mg ml-1 of dopamine. Then, ABS composed of polymers, salts and ionic liquids were evaluated to optimize the laccase confinement in one phase while PDA is recovered in the opposite phase. The most promising ABS allowing the separation of laccase from the reaction product is composed of polypropylene glycol (400 g mol-1) and K2HPO4. The polymerization of dopamine in ABS leads to a remarkable improvement of polymerization of 3.9-fold in comparison to the conventional chemical PDA polymerization. The phase containing the confined laccase was reused for four consecutive reaction cycles, with a relative polymerization of 68.9% in the last cycle. The results of this work proved that ABS are a promising approach to create a liquid support for enzyme reuse allowing the process intensification efforts. The use of biocatalysts in ABS emerges as sustainable and alternative platforms from environmental and techno-economic points of view.

Toxicological effects of the rare earth element neodymium in Mytilus galloprovincialis.

The wide range of applications of rare earth elements (REE) is leading to their occurrence in worldwide aquatic environments. Among the most popular REE is Neodymium (Nd), being widely used in permanent magnets, lasers, and glass additives. Neodymium-iron-boron (NdFeB) magnets is the main application of Nd since they are used in electric motors, hard disk drives, speakers and generators for wind turbines. Recent studies have already evaluated the toxic potential of different REE, but no information is available on the effects of Nd towards marine bivalves. Thus, the present study evaluated the biochemical alterations caused by Nd in the mussel Mytilus galloprovincialis exposed to this element for 28 days. The results obtained clearly demonstrated that Nd was accumulated by mussels, leading to mussel's metabolic capacity increase and GLY expenditure, in an attempt to fuel up defense mechanisms. Antioxidant and biotransformation defenses were insufficient in the elimination of ROS excess, resulting from the presence of Nd and increased electron transport system activity, which caused cellular damages (measured by lipid peroxidation) and loss of redox balance (assessed by the ratio between reduced and oxidized glutathione). The results obtained clearly highlight the potential toxicity of REEs and, in particular of Nd, with impacts at cellular level, which may have consequences in mussel's survival, growth and reproduction, affecting mussel's population.

Relationship between performance, dry-land power and kinematics in master swimmers.

The purpose of the study was to analyze the relationships between sprint swimming performance, dry-land power, and kinematics in master swimmers. Twenty-two male master swimmers were separated in two groups based on their chronological age: (i) 30-39 years and; (ii) 40-49 years. Maximum dry-land power was determined through counter movement jump and 3 kg medicine ball throwing (Hmax and Tmax, respectively). Kinematic determinants of performance were measured during a maximal bout of 15, 25 and 50 m front crawl (T15, T25, T50). Stroke frequency (SF), stroke length (SL) and stroke index (SI) were calculated as kinematical aspects of the stroke. In the 30-39 group, SI25 was correlated to T25 (r = -0.76, p < 0.01, η2 = 0.96), the same was observed between SI50 and T50 (r = -0.83, p < 0.01, η2 = 0.96). Only SI50 was significantly correlated to T50 (r = 0.86, p < 0.01, η2 = 0.97) in the 40-49 years age cohort. In dryland power variables, Hmax and Tmax were only correlated in the younger master swimmers group (r = -0.87, p < 0.01, η2 = 0.97). There were no significant differences (p < 0.05) between younger (30-39 years) and older (40-49 years) swimmers groups in dry-land tests (Hmax 28.5 ± 5.9 vs. 26.5 ± 3.9 cm and Tmax 4.2 ± 1.0 vs. 4.2 ± 1.1 m). Our results suggest that swimming performance in younger master swimmers (30-39 years) seem more dependent on kinematic swimming variables than on strength parameters, which were most related to swimming performance in the older master swimmers (40-49 years).

[Fetal growth and activity at 20 to 24 weeks of gestation (preliminary study)]. / Crescimento e actividade fetal às 20-24 semanas de gestação(estudo preliminar).

BACKGROUND: Recent researches show that psychological development begins much before birth and prenatal influences can explain a significant part of the future variability in infants' behaviour and development. AIMS: The aim of this study was to characterize the fetal development between 20 and 24 weeks of gestation, related to the measures of fetal growth-- iparietal diameter, abdominal circumference, head circumference, femur length and fetal weight-- and fetal activity--fetal heart rate and fetal movements. We also tried to establish if there are any differences in these measures related to the mothers' and fetus' sociodemographic features, obstetrical conditions and exposure to drugs. METHOD: The sample of this study involved 48 fetus (52.1% female and 47.9% male) with an estimated gestational age (GA) between 20-24 weeks (Mean = 21 weeks and 1 day), whose mothers had appointments at the Obstetric and Gynaecological medical consultation of Júlio Dinis Maternity Hospital (MJD, Oporto). A video tape of the fetal behaviour was made and ultrasound biometry measurements were collected from the morphological ultrasound report. RESULTS: A statistical analysis of fetal data, after gestational age control, showed differences in fetal growth measures related to mothers' occupational status [F(1,41) = 7.28; p = .000], marital status [F(1,41) = 2.61; p = .04], household arrangements [F(1,41) = 2.91; p = .03] and coffee consumption [F(1,40) = 2.55; p = .05]. Differences in fetal activity measures (fetal heart rate) associated to fetus gender [F(1,16) = 5.84; p = .009] were also found. CONCLUSIONS: We can conclude about the sensibility of fetal development to prenatal factors related to the mothers' and fetus' sociodemographic features and exposure to drugs.