Biodegradation of Plastics and Formation of PHA Bioplastics—A Circular Bioeconomy Approach

This work is financed by national funds from FCT—Fundação para a Ciência e a Tecnologia, IP, in the scope of the project UIDP/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB, and UID/CTM/50025/2020-2023 of the Research Unit on Materials Science—CENIMAT–I3N. FCT/MCTES through project grants PTDC/QUIQUI/119116/2010, PTDC/GEO-FIQ/5162/2014, , and PTDC/EEI-EEE/0415/2021.Plastics are present in the majority of daily-use products worldwide. Due to society’s production and consumption patterns, plastics are accumulating in the environment, causing global pollution issues and intergenerational impacts. Our work aims to contribute to the development of solutions and sustainable methods to mitigate this pressing problem, focusing on the ability of marine-derived actinomycetes to accelerate plastics biodegradation and produce polyhydroxyalkanoates (PHAs), which are biodegradable bioplastics. The thin plastic films’ biodegradation was monitored by weight loss, changes in the surface chemical structure (Infra-Red spectroscopy FTIR-ATR), and by mechanical properties (tensile strength tests). Thirty-six marine-derived actinomycete strains were screened for their plastic biodegradability potential. Among these, Streptomyces gougerotti, Micromonospora matsumotoense, and Nocardiopsis prasina revealed ability to degrade plastic films—low-density polyethylene (LDPE), polystyrene (PS) and polylactic acid (PLA) in varying conditions, namely upon the addition of yeast extract to the culture media and the use of UV pre-treated thin plastic films. Enhanced biodegradation by these bacteria was observed in both cases. S. gougerotti degraded 0.56% of LDPE films treated with UV radiation and 0.67% of PS films when inoculated with yeast extract. Additionally, N. prasina degraded 1.27% of PLA films when these were treated with UV radiation, and yeast extract was added to the culture medium. The main and most frequent differences observed in FTIR-ATR spectra during biodegradation occurred at 1740 cm−1, indicating the formation of carbonyl groups and an increase in the intensity of the bands, which indicates oxidation. Young Modulus decreased by 30% on average. In addition, S. gougerotti and M. matsumotoense, besides biodegrading conventional plastics (LDPE and PS), were also able to use these as a carbon source to produce degradable PHA bioplastics in a circular economy conceptpublishersversionpublishe

Magnetic/plasmonic MnFe2O4/Au nanoparticles covered with lipid bilayers for applications in thermotherapy

In this work, three different types of magnetic/plasmonic nanoparticles were prepared: core-shell nanoparticles with a manganese ferrite core and a gold shell; plasmonic gold nanoparticles decorated with magnetic nanoparticles of manganese ferrite; and magnetic nanoparticles of manganese ferrite decorated with plasmonic gold nanoparticles. The structural, spectroscopic and magnetic properties of these nanoparticles were evaluated. In order to further develop applications in cancer therapy, the prepared mixed nanoparticles were covered with a lipid bilayer. The local heating capability of these nanosystems was tested through the quenching of rhodamine fluorescence incorporated in the lipid layer.Financial support by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. A.R.O Rodrigues thanks the FCT for SFRH/BD/90949/2012 PhD grant and funding to MAP-Fis Doctoral Program.info:eu-repo/semantics/publishedVersio

Chromosomal organization of the 18S and 5S rRNAs and histone H3 genes in Scarabaeinae coleopterans: insights into the evolutionary dynamics of multigene families and heterochromatin

<p>Abstract</p> <p>Background</p> <p>Scarabaeinae beetles show a high level of macro-chromosomal variability, although the karyotypic organization of heterochromatin and multigene families (rDNAs and histone genes) is poorly understood in this group. To better understand the chromosomal organization and evolution in this group, we analyzed the karyotypes, heterochromatin distribution and chromosomal locations of the rRNAs and histone H3 genes in beetles belonging to eight tribes from the Scarabaeinae subfamily (Coleoptera, Scarabaeidae).</p> <p>Results</p> <p>The number of 18S rRNA gene (a member of the 45S rDNA unit) sites varied from one to 16 and were located on the autosomes, sex chromosomes or both, although two clusters were most common. Comparison of the 45S rDNA cluster number and the diploid numbers revealed a low correlation value. However, a comparison between the number of 45S rDNA sites per genome and the quantity of heterochromatin revealed (i) species presenting heterochromatin restricted to the centromeric/pericentromeric region that contained few rDNA sites and (ii) species with a high quantity of heterochromatin and a higher number of rDNA sites. In contrast to the high variability for heterochromatin and 45S rDNA cluster, the presence of two clusters (one bivalent cluster) co-located on autosomal chromosomes with the 5S rRNA and histone H3 genes was highly conserved.</p> <p>Conclusions</p> <p>Our results indicate that the variability of the 45S rDNA chromosomal clusters is not associated with macro-chromosomal rearrangements but are instead related to the spread of heterochromatin. The data obtained also indicate that both heterochromatin and the 45S rDNA loci could be constrained by similar evolutionary forces regulating spreading in the distinct Scarabaeinae subfamily lineages. For the 5S rRNA and the histone H3 genes, a similar chromosomal organization could be attributed to their association/co-localization in the Scarabaeinae karyotypes. These data provide evidence that different evolutionary forces act at the heterochromatin and the 45S rDNA loci compared to the 5S rRNA and histone H3 genes during the evolution of the Scarabainae karyotypes.</p

Magnetoliposomes based on NixCu1-xFe2O4 or NiFe2-yAlyO4 nanocrystals for applications in magnetic separation and classification

Ferrites are a broad class of compounds with general formula MFe2O4, where M stands for a divalent metallic cation. Among these, copper ferrite (CuFe2O4) presents a moderate saturation magnetization, while nickel ferrite (NiFe2O4) holds a large one. Mixed ferrites with composition NixCu1-xFe2O4 were then prepared by coprecipitation method, in order to control the saturation magnetization with the fraction of Ni. Another possibility is the partial substitution of iron atoms with aluminium, as NiAl2O4 nanocrystals show very low saturation magnetization. Thus, ferrites of NiFe2-yAlyO4 composition were also obtained. XRD spectra of the obtained nanoparticles show the spinel-type crystalline phase. Solid magnetoliposomes of the prepared mixed ferrites were obtained, and their bilayer structure was proven by the use lipophilic fluorescence probes.info:eu-repo/semantics/publishedVersio

Hydrophobic DES Based on Menthol and Natural Organic Acids for Use in Antifouling Marine Coatings

Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.Marine biofouling negatively impacts industries with off-shore infrastructures, such as naval, oil, and aquaculture. To date, there are no ideal sustainable, economic, and environmentally benign solutions to deal with this phenomenon. The advances achieved in green solvents, as well as its application in different industries, such as pharmaceutical and biotechnology, have promoted the emergence of deep eutectic systems (DES). These eutectic systems have applications in various fields and can be revolutionary in the marine-based industrial sector. In this study, the main objective was to investigate the potential use of hydrophobic DES (HDES) based on menthol and natural organic acids for their use as marine antifouling coatings. Our strategy encompassed the physicochemical characterization of different formulations, which allowed us to identify the most appropriate molar ratio and intermolecular interactions for HDES formations. The miscibility of the resulting HDES with the marine coating has been evaluated and proven to be successful. The Men/OL (1:1) system proved to be the most promising in terms of cost-production and thus was the one used in subsequent antifouling tests. The cytotoxicity of this HDES was evaluated using an in vitro cell model (HaCat cells) showing no significant toxicity. Furthermore, the application of this system incorporated into coatings that are used in marine structures was also studied using marine species (Mytilus edulis mussels and Patella vulgata limpets) to evaluate both their antifouling and ecotoxicity effects. HDES Men/OL (1:1) incorporated in marine coatings was promising in reducing marine macrofouling and also proved to be effective at the level of microfouling without viability impairment of the tested marine species. It was revealed to be more efficient than using copper oxide, metallic copper, or ivermectin as antifouling agents. Biochemical assays performed on marine species showed that this HDES does not induce oxidative stress in the tested species. These results are a strong indication of the potential of this HDES to be sustainable and efficiently used in marine fouling control technologies.publishersversionpublishe

Synthesis and characterization of magnetoliposomes containing nickel ferrite nanoparticles covered with gold for applications in phototherapy

In this work, nanoparticles with magnetic/plasmonic properties of nickel ferrite decorated with gold nanoparticles and core/shell nickel ferrite/gold nanoparticles were prepared and characterized. The synthesized nanoparticles were used for the preparation of solid magnetoliposomes (SMLs), these systems being our target of study. The nanosystems were evaluated for the ability to cause local heating upon excitation in the gold plasmonic band. For that, fluorescence quenching of rhodamine B incorporated in SMLs lipid layer was measured. The developed multifunctional nanosystems have shown promising results for application in combined cancer therapy (chemo/phototherapy).UIDB/04650/2020; PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020

Organic versus conventional tomatoes: Influence on physicochemical parameters, bioactive compounds and sensorial attributes

The effect of organic and conventional agricultural systems on the physicochemical parameters, bioactive compounds content, and sensorial attributes of tomatoes (‘‘Redondo’’ cultivar) was studied. The influence on phytochemicals distribution among peel, pulp and seeds was also accessed. Organic tomatoes were richer in lycopene (+20%), vitamin C (+30%), total phenolics (+24%) and flavonoids (+21%) and had higher (+6%) in vitro antioxidant activity. In the conventional fruits, lycopene was mainly concentrated in the pulp, whereas in the organic ones, the peel and seeds contained high levels of bioactive compounds. Only the phenolic compounds had a similar distribution among the different fractions of both types of tomatoes. Furthermore, a sensorial analysis indicated that organic farming improved the gustative properties of this tomato cultivar

Magnetic nanoparticles covered by or entrapped in lipid bilayers: Advances towards dual cancer therapy

In this work, both aqueous magnetoliposomes (magnetic nanoparticles entrapped in liposomes) and solid magnetoliposomes (a cluster of particles covered by a lipid bilayer) have been developed, containing either nickel/silica core/shell nanoparticles, nickel ferrite or manganese ferrite nanoparticles, with diameters below 150 nm, suitable for biomedical applications. Moreover, both aqueous (AMLs) and solid (SMLs) magnetoliposomes show a superparamagnetic behavior, the SMLs exhibiting a high saturation magnetization.Financial support by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and UID/QUI/00686/2016 is acknowledged. A.R.O Rodrigues thanks the FCT for SFRH/BD/90949/2012 PhD grant and funding to MAP-Fis Doctoral Program.info:eu-repo/semantics/publishedVersio

Phenylketonuria: Protein content and amino acids profile of dishes for phenylketonuric patients. The relevance of phenylalanine

Phenylketonuria is an inborn error of metabolism, involving, in most cases, a deficient activity of phenylalanine hydroxylase. Neonatal diagnosis and a prompt special diet (low phenylalanine and natural-protein restricted diets) are essential to the treatment. The lack of data concerning phenylalanine contents of processed foodstuffs is an additional limitation for an already very restrictive diet. Our goals were to quantify protein (Kjeldahl method) and amino acid (18) content (HPLC/fluorescence) in 16 dishes specifically conceived for phenylketonuric patients, and compare the most relevant results with those of several international food composition databases. As might be expected, all the meals contained low protein levels (0.67–3.15 g/100 g) with the highest ones occurring in boiled rice and potatoes. These foods also contained the highest amounts of phenylalanine (158.51 and 62.65 mg/100 g, respectively). In contrast to the other amino acids, it was possible to predict phenylalanine content based on protein alone. Slight deviations were observed when comparing results with the different food composition databases