Karyotype variability in tropical maize sister inbred lines and hybrids compared with kys standard line.

Maize karyotype variability has been extensively investigated. The identification of maize somatic and pachytene chromosomes has improved with the development of fluorescence in situ hybridization (FISH) using tandemly repeated DNA sequences as probes. We identified the somatic chromosomes of sister inbred lines that were derived from a tropical flint maize population (Jac Duro [JD]), and hybrids between them, using FISH probes for the 180-bp knob repeat, centromeric satellite (CentC), centromeric satellite 4 (Cent4), subtelomeric clone 4-12-1, 5S ribosomal DNA and nucleolus organizing region DNA sequences. The observations were integrated with data based on C-banded mitotic metaphases and conventional analysis of pachytene chromosomes. Heterochromatic knobs visible at pachynema were coincident with C-bands and 180-bp FISH signals on somatic chromosomes, and most of them were large. Variation in the presence of some knobs was observed among lines. Small 180-bp knob signals were invariant on the short arms of chromosomes 1, 6, and 9. The subtelomeric 4-12-1 signal was also invariant and useful for identifying some chromosomes. The centromere location of chromosomes 2 and 4 differed from previous reports on standard maize lines. Somatic chromosomes of a JD line and the commonly used KYS line were compared by FISH in a hybrid of these lines. The pairing behavior of chromosomes 2 and 4 at pachytene stage in this hybrid was investigated using FISH with chromosome-specific probes. The homologues were fully synapsed, including the 5S rDNA and CentC sites on chromosome 2, and Cent4 and subtelomeric 4-12-1 sites on chromosome 4. This suggests that homologous chromosomes could pair through differential degrees of chromatin packaging in homologous arms differing in size. The results contribute to current knowledge of maize global diversity and also raise

Machine learning-assisted optimization of drug combinations in zeolite-based delivery systems for melanoma therapy

Two independent artificial neural network (ANN) models were used to determine the optimal drug combination of zeolite-based delivery systems (ZDS) for cancer therapy. The systems were based on the NaY zeolite using silver (Ag+) and 5-fluorouracil (5-FU) as antimicrobial and antineoplastic agents. Different ZDS samples were prepared, and their characterization indicates the successful incorporation of both pharmacologically active species without any relevant changes to the zeolite structure. Silver acts as a counterion of the negative framework, and 5-FU retains its molecular integrity. The data from the A375 cell viability assays, involving ZDS samples (solid phase), 5-FU, and Ag+ aqueous solutions (liquid phase), were used to train two independent machine learning (ML) models. Both models exhibited a high level of accuracy in predicting the experimental cell viability results, allowing the development of a novel protocol for virtual cell viability assays. The findings suggest that the incorporation of both Ag and 5-FU into the zeolite structure significantly potentiates their anticancer activity when compared to that of the liquid phase. Additionally, two optimal AgY/5-FU@Y ratios were proposed to achieve the best cell viability outcomes. The ZDS also exhibited significant efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus); the predicted combination ratio is also effective against S. aureus, underscoring the potential of this approach as a therapeutic option for cancer-associated bacterial infections.FCT - Fundação para a Ciência e a Tecnologia (UIDB/04469/2020).A.R.B. and V.I. express their gratitude to the Portuguese Foundation for Science and Technology (FCT) for providing funding through the Ph.D. Grants SFRH/BD/141058/2018 and UI/BD/152219/2021, respectively. This research work has received financial support from national funds provided by FCT/MCTES (PIDDAC) under the projects UID/QUI/0686/2020 (CQ-UM), UIDB/04469/2020 (CEB), and UIDP/50026/2020 (ICVS). Additionally, the projects of BioTecNorte (operation NORTE-01-0145-FEDER-000004 and NORTE-01-0145-FEDER-000055) are supported by the Northern Portugal Regional Operational Program (NORTE 2020) under the Portugal 2020 Partnership Agreement, cofunded by the European Regional Development Fund (ERDF). This work was also supported by the “Contrato Programa” UIDB/04050/2020 funded by national funds through the FCT I.P. The authors also thank Patrícia R. Correia for their contribution to cell viability studies

Metal ion-zeolite nanomaterials for chemodynamic therapy

A new therapeutic approach called chemodynamic therapy (CDT), which can be defined as specific OH generation in cancer cells via Fenton reactions, was recently proposed.1 The advantages of CDT can be ascribed to the higher specificity, no external field penetration depth restriction, lower side effects in normal tissues, higher-level ROS generation, lack of equipment restrictions, and non-multidrug resistance, showing the promising future of CDT for clinical translation. The varied and highly controlled structural along with the chemical properties of inorganic nanomaterials, like zeolites, make them suitable for this type of CDT. Zeolites already proved to be interesting candidates for medical and healthcare applications, and also as Fenton heterogeneous catalysts for organic degradation. The aim of this study was to assess the dual activity (antibacterial and anticancer) of metal ion-zeolite nanomaterials. The prepared metal ion-zeolite nanomaterials were tested in vitro using a human skin cancer cell line, A375, and the anti-bacterial activity was evaluated against Escherichia coli, Staphylococcus aureus and MRSA. Results obtained so far suggest that metal ion-zeolite nanomaterials could be explored as antibacterial and/or anticancer agents.info:eu-repo/semantics/publishedVersio

Optimization of iron-ZIF-8 catalysts for degradation of tartrazine in water by Fenton-like reaction

Optimization of iron zeolitic imidazole framework-8 (FeZIF-8) nanoparticles, as heterogeneous catalysts, were synthesized and evaluated by the Fenton-like reaction for to degrade tartrazine (Tar) in aqueous environment. To achieve this, ZIF-8 nanoparticles were modified with different iron species (Fe2+ or Fe3O4), and subsequently assessed through the Fenton-like oxidation. The effect of different parameters such as the concentration of hydrogen peroxide, the mass of catalyst and the contact time of reaction on the degradation of Tar by Fenton-like oxidation was studied by using the Box-Behnken design (BBD). The BBD model indicated that the optimum catalytic conditions for Fenton-like reaction with an initial pollutant concentration of 30ppm at pH 3.0 were T=40°C and 12mM of H2O2, 2g/L of catalyst and 4h of reaction. The maximum Tar conversion value achieved with the best catalyst, Fe1ZIF-8, was 66.5% with high mineralization (in terms of decrease of total organic carbon TOC), 44.2%. To assess phytotoxicity, the germination success of corn kernels was used as an indicator in the laboratory. The results show that the catalytic oxidation by Fenton-like reaction using heterogeneous iron ZIF-8 catalysts is a viable alternative for treating contaminated effluents with organic pollutants and highlighted the importance of the validation of the optimized experimental conditions by mathematical models.O.A. thanks to ERASMUS + Program for the mobility Ph.D. grant and A.R.B. thanks to Fundação para Ciência e Tecnologia, FCT (Portugal) for her Ph.D. grant (SFRH/BD/141058/2018). This research work has been funded by national funds funded through FCT/MCTES (PIDDAC) over the projects: LA/P/0045/2020 (ALiCE), UIDB/50020/2020 and UIDP/50020/2020 (LSRE-LCM), Centre of Chemistry (UID/QUI/0686/2020), CEB (UIDB/04469/2020) and project BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by the Northern Portugal Regional Operational Program (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

Sindrome de X frágil: pessoas, contextos & percursos

Projeto financiado pela FCT (PTDC/CPE/115276/2009)

Sustainable fluorescent dye-faujasite zeolite systems as tools for cancer bioimaging

The use of fluorescent nanoparticles for biological and medical applications has attracted great attention due to their several advantages compared to conventional fluorescent dyes. However, there is also a need for sustainable and versatile alternatives, alongside the streamlining of complex synthesis or preparations. In this work, we study the potential of the faujasite zeolite structure to encapsulate dye molecules and be applied as a bioimaging agent for cancer cells. The commercial zeolites NaY, USY, and NaX were used to encapsulate Rhodamine B (RhB) or Fluorescein (F) dyes, which present a similar tetracycle core structure. Different characterization techniques confirmed the encapsulation of the dyes and their stability. The photophysical characterization of the encapsulated RhB and F dyes was also elucidated by UV–visible and fluorescence spectroscopy. Biocompatibility was tested in different cancer cell lines and confocal laser scanning electron microscopy (CLSM) was used to track the fluorescent dye-containing zeolites. Remarkably, the dye-containing zeolite RhB@USY showed interesting multiluminescent labeling properties that make it a suitable agent for bioimaging applications. The economic feasibility of the developed fluorescent dye-zeolite probes was also examined through a detailed cost analysis, which further highlights their commercial potential.A.R.B. thanks to Foundation for Science and Technology (FCT, Portugal) for her Ph.D. grant (SFRH/BD/141058/ 2018). This research work has been funded by national funds funded through FCT/MCTES (PIDDAC) over the projects: project UIDB/50026/2020 and UIDP/50026/2020, the project NORTE-01-0145-FEDER-000055, Centre of Chemistry (UID/QUI/0686/2020), CEB (UIDB/04469/2020) and LABBELS (LA/P/0029/2020), and project BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by the Norte Portugal Regional Operational Program (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The authors thank Professor Mikhail Vasilevskiy for critical discussions.info:eu-repo/semantics/publishedVersio