João Pinto da Costa

(Nano)plastics in the environment - Sources, fates and effects.

Abstract There has been a considerable increase on research of the ecological consequences of microplastics released into the environment, but only a handful of works have focused on the nano-sized particles of polymer-based materials. Though their presence has been difficult to adequately ascertain, due to the inherent technical difficulties for isolating and quantifying them, there is an overall consensus that these are not only present in the environment – either directly released or as the result of weathering of larger fragments – but that they also pose a significant threat to the environment and human health, as well. The reduced size of these particulates ( In this review, we describe the most relevant sources of nanoplastics and offer some insights into their fate once released into the environment. Furthermore, we overview the most prominent effects of these small particulates, while identifying the key challenges scientists currently face in the research of nanoplastics in the environment. Lastly, we give a brief summary of the economic impacts of the pollution caused by plastic litter – a potential key source of nanoplastics – in the oceans, the most common destination of these contaminants.

Antimicrobial peptides: an alternative for innovative medicines?

Antimicrobial peptides are small molecules with activity against bacteria, yeasts, fungi, viruses, bacteria, and even tumor cells that make these molecules attractive as therapeutic agents. Due to the alarming increase of antimicrobial resistance, interest in alternative antimicrobial agents has led to the exploitation of antimicrobial peptides, both synthetic and from natural sources. Thus, many peptide-based drugs are currently commercially available for the treatment of numerous ailments, such as hepatitis C, myeloma, skin infections, and diabetes. Initial barriers are being increasingly overcome with the development of cost-effective, more stable peptides. Herein, we review the available strategies for their synthesis, bioinformatics tools for the rational design of antimicrobial peptides with enhanced therapeutic indices, hurdles and shortcomings limiting the large-scale production of AMPs, as well as the challenges that the pharmaceutical industry faces on their use as therapeutic agents.

Femtosecond control of electric currents in metallic ferromagnetic heterostructures

The idea to use not only the charge but also the spin of electrons in the operation of electronic devices has led to the development of spintronics, causing a revolution in how information is stored and processed. A novel advancement would be to develop ultrafast spintronics using femtosecond laser pulses. Employing terahertz (10(12) Hz) emission spectroscopy and exploiting the spin-orbit interaction, we demonstrate the optical generation of electric photocurrents in metallic ferromagnetic heterostructures at the femtosecond timescale. The direction of the photocurrent is controlled by the helicity of the circularly polarized light. These results open up new opportunities for realizing spintronics in the unprecedented terahertz regime and provide new insights in all-optical control of magnetism.

Identification of 1-palmitoyl-2-linoleoyl- phosphatidylethanolamine modifications under oxidative stress conditions by LC-MS/MS

Phosphatidylethanolamines are a major class of phospholipids found in cellular membranes. Identification of the alterations in these phospholipids, induced by free radicals, could provide new tools for in vivo diagnosis of oxidative stress. In this study, 1-palmitoyl-2-linoleoyl-phosphatidylethanolamine oxidation products, induced by the hydroxyl radical, were studied using LC-MS and LC-MS/MS. Data obtained allowed the identification and separation of isomeric oxidative products with modifications in the sn-2 acyl chain, attributed to long- and short-chain products. Among long-chain products keto, keto-hydroxy, hydroxy, poly-hydroxy, peroxy and hydroxy-peroxy derivatives were identified. Product ions formed by loss of two H2O molecules vs loss of HOOH, allowed the identification of, respectively, di- (or poli-) hydroxy vs peroxy derivatives. Location of functional groups was determined by the product ions formed by cleavage of C-C bonds, in the vicinity of the oxidation positions, allowing the identification of C9, C12 and C13 as the predominant substituted positions. Short-chain products identified comprised aldehydes, hydroxy-aldehydes and carboxylic derivatives, with modified sn-2 acyl lengths of C7-C9 and C11, C12. Among the short-chain products identified, C9 products showed higher relative abundance.

A synopsis on aging-Theories, mechanisms and future prospects.

Answering the question as to why we age is tantamount to answering the question of what is life itself. There are countless theories as to why and how we age, but, until recently, the very definition of aging - senescence - was still uncertain. Here, we summarize the main views of the different models of senescence, with a special emphasis on the biochemical processes that accompany aging. Though inherently complex, aging is characterized by numerous changes that take place at different levels of the biological hierarchy. We therefore explore some of the most relevant changes that take place during aging and, finally, we overview the current status of emergent aging therapies and what the future holds for this field of research. From this multi-dimensional approach, it becomes clear that an integrative approach that couples aging research with systems biology, capable of providing novel insights into how and why we age, is necessary.

Biodegradation of polyethylene microplastics by the marine fungus Zalerion maritimum

Plastic yearly production has surpassed the 300milliontons mark and recycling has all but failed in constituting a viable solution for the disposal of plastic waste. As these materials continue to accumulate in the environment, namely, in rivers and oceans, in the form of macro-, meso-, micro- and nanoplastics, it becomes of the utmost urgency to find new ways to curtail this environmental threat. Multiple efforts have been made to identify and isolate microorganisms capable of utilizing synthetic polymers and recent results point towards the viability of a solution for this problem based on the biodegradation of plastics resorting to selected microbial strains. Herein, the response of the fungus Zalerion maritimum to different times of exposition to polyethylene (PE) pellets, in a minimum growth medium, was evaluated, based on the quantified mass differences in both the fungus and the microplastic pellets used. Additionally, molecular changes were assessed through attenuated total reflectance Fourier transform Infrared Spectroscopy (FTIR-ATR) and Nuclear Magnetic Resonance (NMR). Results showed that, under the tested conditions, Z. maritimum is capable of utilizing PE, resulting in the decrease, in both mass and size, of the pellets. These results indicate that this naturally occurring fungus may actively contribute to the biodegradation of microplastics, requiring minimum nutrients.

Magnetic chelating nanoprobes for enrichment and selective recovery of metalloproteases from human saliva

New magnetic nanoprobes based on surface-functionalized magnetite particles were synthesized and used to selectively capture metalloproteases from human saliva samples. In addition to their high specific surface area, these nanoparticles have metal ion chelating moieties grafted on their surface by the reaction with the organosilane EDTA-TMS ((N-(trimethoxysilylpropyl)-ethylenediaminetriacetate trisodium salt). The most distinct feature of these particles is their capability to selectively recover metalloproteases even in highly diluted saliva samples. The high affinity of these materials for metalloproteases was attributed to the formation of chelates between the chelating moieties and the metal ions of metalloproteases. These magnetic particles exhibited high colloidal stability in the biological standard buffers MES, HEPES, TEAB and Tris-HCl, within a significant pH range (pH 5-9) and, due to their magnetic features, enabled a fast separation of the metalloproteases from the medium by simply applying an external magnetic field. Thus, these materials were proven to be valuable probes for the selective enrichment and rapid recovery of metalloproteases from human saliva, particularly when dealing with trace amounts of material.

Bionanoconjugation for proteomics applications - An overview.

Formed as an interdisciplinary domain on the basis of Human Genome Project, Proteomics aims at the large-scale study of proteins. The enthusiasm that resulted from obtaining the complete human genetic information has, however, been chastened by the realization that this information contributes little to the comprehension and knowledge of the expressed proteins. In the wake of this realization, the Human Proteome Project (HUPO) was founded, which is a global, collaborative initiative, aiming at the complete characterization of the proteins of all protein-coding genes. Nonetheless, the rapid detection of these molecules in complex biological samples under conditions considered to be of clinical relevance is extremely difficult, requiring the development of very sensitive, robust, reproducible and high throughput platforms. Nanoproteomics has emerged as a feasible, promising option, offering short assay times, low sample consumption, ultralow detection and high throughput capacity. Additionally, the successful synthesis of biomolecules and nanoparticle hybrids yields systems which often exhibit new or improved features. Herein, we overview the recent advances in bioconjugation at the nanolevel and, specifically, their application in Proteomics, discussing not only the merits and prospects of Proteomics, but also present day limitations.

Chemical and structural characterization of Pholiota nameko extracts with biological properties

Edible mushrooms including Pholiota nameko are excellent sources of extractable bioactive compounds with much to explore. Enzymatic extractions with Cellulase and Viscozyme were responsible for highest extraction yields (67-77%). No strong antioxidant activity was observed although extracts were able to scavenge ABTS(+) and OH(+). Potential prebiotic activity was observed in all extracts, some increasing 1.4-2 Log cycles of Lactobacillus acidophilus La-5 and Bifidobacterium animalis BB12. 30-50% α-glucosidase inhibition was observed in ultrasound, Flavourzyme and Cellulase extracts. Flavourzyme and Cellulase extracts are richer in macro (Mg, K and P) and micro elements (Zn, Mn and Fe) in comparison to mushroom. Monosaccharides content and profile varied slightly among both extracts with predominance of glucose, galactose and mannose with no uronic acids detection; Flavourzyme extract reported higher free amino acids content. Presence of α and β-glycosidic structures such as glucans and glucan-protein complexes are among the polysaccharides found in both extracts.

Microplastics in the environment: Challenges in analytical chemistry - A review

Microplastics can be present in the environment as manufactured microplastics (known as primary microplastics) or resulting from the continuous weathering of plastic litter, which yields progressively smaller plastic fragments (known as secondary microplastics). Herein, we discuss the numerous issues associated with the analysis of microplastics, and to a less extent of nanoplastics, in environmental samples (water, sediments, and biological tissues), from their sampling and sample handling to their identification and quantification. The analytical quality control and quality assurance associated with the validation of analytical methods and use of reference materials for the quantification of microplastics are also discussed, as well as the current challenges within this field of research and possible routes to overcome such limitations.