Dora Martins Teixeira

Study on the use of Typha spp. for the phytotreatment of water contaminated with ibuprofen

Several studies on phytotoxic effects caused by organic xenobiotics and their removal from water by macrophytes have already been performed to evaluate the usefulness of these plants for phytoremediation technologies. In this context, a study was conducted to assess Typha spp.s ability to withstand and remove, from water, the non-steroidal anti-inflammatory drug ibuprofen. For an initial ibuprofen concentration of 20 µg L−1, Typha removed nearly 60% of it within the first 24 h, attaining over 99% removal by the end of the assay (21 days). Exposure to higher ibuprofen concentrations did affect Typhas growth but, by the end of the assays, plants’ growth as well as photosynthetic pigments approached normal values. An alteration in antioxidant enzymes activities (superoxide dismutase, catalase, guaiacol peroxidase) indicated that both roots and leaves were affected by the xenobiotic. Eventually, Typha seemed able to cope with ibuprofens induced oxidative damage suggesting its ability for phytotreatment of waters contaminated with ibuprofen.

Ultra-sensitive voltammetric sensor for trace analysis of carbamazepine

A multi-walled carbon nanotubes (MWCNTs) film-coated glassy carbon electrode (GCE) was used for the voltammetric determination of carbamazepine (CBZ). The results showed that this simple modified electrode exhibited excellent electrocatalytic activity towards the oxidation of CBZ. The voltammetric response of CBZ at this film-modified electrode increased significantly when compared with that at a bare glassy carbon electrode and the sensor response was reproducible. The proposed method was applied to the quantification of CBZ in wastewater samples, collected in a municipal wastewater treatment plant, and in pharmaceutical formulations. The developed methodology yields results in accord with those obtained by chromatographic techniques commonly used in the quantification of pharmaceutical compounds in real samples. Good recoveries have been obtained and the limits of detection and quantification (40 and 140 nM, respectively) are among the lowest that have been reported to date for this pharmaceutical compound using voltammetric techniques.

Atenolol removal in microcosm constructed wetlands

Microcosm constructed wetland systems established with a matrix of light expanded clay aggregates (LECA) and Typha spp. or Phragmites australis were used to evaluate their ability to remove atenolol from wastewater. Combined with an efficient SPE concentration step, the use of HPLC-DAD yielded an analytical method for atenolol quantification with very low LOQ (9 ng mL−1) and high reproducibility (RSD < 4%). Overall removal efficiencies of 92.5% and 94.5% were achieved after a retention time of only 4 days with the microcosm systems planted with Phragmites australis and Typha spp., respectively. The removal kinetics was characterised by an initial fast step (removal of about 75% after just 24 h) which is mainly attributable to adsorption on the LECA matrix. Atenolol removal in LECA beds continues to increase in a steady pace up to the end of the assay (8 days) being nevertheless about 5–10% lower than those observed in the planted beds after the first 4 days. For the retention time of 4 days most of the atenolol is removed by the LECA matrix but an additional 12–14% of the overall removal efficiency can be attributed to the Typha and Phragmites plants, which is in agreement with other published reports. Despite the fact that further tests using larger-scale flowing systems are required to evaluate fully the atenolol behaviour in constructed wetlands, this study points to the possible application of these low-cost wastewater treatment systems to treat atenolol contaminated wastewater.

Exploring the potential of novel biomixtures and Lentinula edodes fungus for the degradation of selected pesticides. Evaluation for use in biobed systems

An approach to reduce the contamination of water sources with pesticides is the use of biopurificaction systems. The active core of these systems is the biomixture. The composition of biomixtures depends on the availability of local agro-industrial wastes and design should be adapted to every region. In Portugal, cork processing is generally regarded as environmentally friendly and would be interesting to find applications for its industry residues. In this work the potential use of different substrates in biomixtures, as cork (CBX); cork and straw, coat pine and LECA (Light Expanded Clay Aggregates), was tested on the degradation of terbuthylazine, difenoconazole, diflufenican and pendimethalin pesticides. Bioaugmentation strategies using the white-rot fungus Lentinula edodes inoculated into the CBX, was also assessed. The results obtained from this study clearly demonstrated the relevance of using natural biosorbents as cork residues to increase the capacity of pesticide dissipation in biomixtures for establishing biobeds. Furthermore, higher degradation of all the pesticides was achieved by use of bioaugmented biomixtures. Indeed, the biomixtures inoculated with L. edodes EL1 were able to mineralize the selected xenobiotics, revelling that these white-rot fungi might be a suitable fungus for being used as inoculum sources in on-farm sustainable biopurification system, in order to increase its degradation efficiency. After 120 days, maximum degradation of terbuthylazine, difenoconazole, diflufenican and pendimethalin, of bioaugmented CBX, was 89.9%, 75.0%, 65.0% and 99.4%, respectively.. The dominant metabolic route of terbuthylazine in biomixtures inoculated with L. edodes EL1 proceeded mainly via hydroxylation, towards production of terbuthylazine-hydroxy-2 metabolite. Finally, sorption process to cork by pesticides proved to be a reversible process, working cork as a mitigating factor reducing the toxicity to microorganisms in the biomixture, especially in the early stages.

HPLC-DAD Quantification of Phenolic Compounds Contributing to the Antioxidant Activity of Maclura pomifera, Ficus carica and Ficus elastica Extracts

Abstract The concentration and antioxidant activity of the known phenolics macluraxanthone, rutin, chlorogenic acid, and psoralen present in M. pomifera, F. carica, and F. elastica extracts were determined to evaluate the plant extracts potency as new antioxidant suppliers. The quantification of the compounds was obtained by HPLC-DAD. The antioxidant activity of plant extracts and compounds was evaluated using DPPH and ABTS methods. The results seem to indicate that these extracts can be promising as new antioxidant suppliers, particularly F. carica and F. elastica leaves because only about 30% and about 50%, respectively, of the total activity was due to the phenolics determined.

Antioxidant activity and cholinesterase inhibition studies of four flavouring herbs from Alentejo

Abstract Essential oils (EOs) and aqueous extracts of aerial parts of four aromatic species, Calamintha nepeta, Foeniculum vulgare, Mentha spicata and Thymus mastichina, from southwest of Portugal were characterised chemically and analysed in order to evaluate their antioxidant potential and cholinesterase inhibitory activities. The main components of EOs were oxygenated monoterpenes, and aqueous extracts were rich in phenol and flavonoid compounds. EOs and aqueous extracts presented a high antioxidant potential, with ability to protect the lipid substrate, free radical scavenging and iron reducing power. Furthermore, EOs and extracts showed AChE and BChE inhibitory activities higher than rivastigmine, the standard drug. Results suggested the potential use of EOs and aqueous extracts of these flavouring herbs as nutraceutical or pharmaceutical preparations to minimise the oxidative stress and the progression of degenerative diseases.

O-coumaric acid ester, a potential early signaling molecule in Pinus pinea and Pisolithus arhizus symbiosis established in vitro

During ectomycorrhizal (ECM) establishment, biochemical signals lead to the development of complex structures in both the plant and the fungus that ultimately result in the formation of an ectomycorrhiza. The cross-talk between partners begins before physical contact. Our objective was to investigate the chemical nature of the signals during the first stages of in vitro mycorrhization of Pinus pinea with Pisolithus arhizus. For this purpose a double-phase solid–liquid medium was expressly developed for the co-culture in order to simplify the extraction and further molecules analysis. O-coumaric acid ester was identified using HPLC–UV and LC–DAD–MS on the second day of co-culture and its presence was detected for up to 10 days. These results contribute to the characterization of biochemical signals during pre-colonization involving conifer species and an ECM fungus, and demonstrate the suitability of the double-phase medium developed for the growth of both organisms and for the analysis of released chemical mediators.

On the Chemical Signature and Origin of Dicoppertrihydroxyformate (Cu2(OH)3HCOO) Formed on Copper Miniatures of 17th and 18th centuries.

A corrosion product rarely reported in the literature has been found on the copper support of three miniature paintings of the 17th and 18th centuries. This product, which has been identified as dicoppertrihydroxyformate (Cu2(OH)3HCOO), is an unusual basic copper formate found on copper artifacts. The identification and characterization of dicoppertrihydroxyformate was carried out directly over the corroded surface of the objects, using a nondestructive approach, which combines the integrated use of various microanalytical techniques. Using this approach, it was possible to obtain a set of new reference data about the natural form of Cu2(OH)3HCOO, that will enable its unambiguous identification in other similar objects. In this work, the probable causes that may have contributed to its formation are also discussed.

Green mitigation strategy for cultural heritage: bacterial potential for biocide production

Several biosurfactants with antagonistic activity are produced by a variety of microorganisms. Lipopeptides (LPPs) produced by some Bacillus strains, including surfactin, fengycin and iturin are synthesized nonribosomally by mega-peptide synthetase (NRPS) units and they are particularly relevant as antifungal agents. Characterisation, identification and evaluation of the potentials of several bacterial isolates were undertaken in order to establish the production of active lipopeptides against biodeteriogenic fungi from heritage assets. Analysis of the iturin operon revealed four open reading frames (ORFs) with the structural organisation of the peptide synthetases. Therefore, this work adopted a molecular procedure to access antifungal potential of LPP production by Bacillus strains in order to exploit the bioactive compounds synthesis as a green natural approach to be applied in biodegraded cultural heritage context. The results reveal that the bacterial strains with higher antifungal potential exhibit the same morphological and biochemical characteristics, belonging to the genera Bacillus. On the other hand, the higher iturinic genetic expression, for Bacillus sp. 3 and Bacillus sp. 4, is in accordance with the culture antifungal spectra. Accordingly, the adopted methodology combining antifungal screening and molecular data is represent a valuable tool for quick identification of iturin-producing strains, constituting an effective approach for confirming the selection of lipopeptides producer strains.