Journal UMinho Science

Exposure to cobalt metal (without tungsten carbide) and some cobalt compounds: a literature review

Amélia Paula Marinho Reis — Wed, 20 Mar 2024 00:00:00 +0000

Cobalt is a natural metallic element with extensive applications across multiple industries, and a critical metal for lithium-ion battery production. Cobalt's only known biological function is its role as a metal component of vitamin B12. Other cobalt compounds have been described as toxic to the environment and the human body following excessive exposure. The International Agency for Research on Cancer (IARC) has classified cobalt, including cobalt metal and soluble cobalt(II) salts, as Group 2A, meaning it is probably carcinogenic to humans. This review aims to present a comprehensive overview of historical and current sources of cobalt in diverse exposure settings, along with its various intake routes. An extensive literature search was conducted between September 2021 and January 2022, analysing over 300 publications. The primary goal of these studies was to identify cobalt sources, intake routes, and exposure pathways. Workers may be exposed to various cobalt compounds and metal powders primarily through inhalation, but exposure can also occur via skin contact or ingestion. For the general population, food typically arises as the predominant source of cobalt exposure. Furthermore, exposure may occur through ambient air, tobacco smoke, and medical implants.

Studying Floristic Composition for the Conservation of Parque das Camélias (Braga Municipality) Biodiversity

Barbara Lages, Ana Castro, Renato Henriques, António Teixeira, Hernâni Gerós — Mon, 25 Mar 2024 00:00:00 +0000

The conservation of biodiversity and the understanding of its distribution patterns play a crucial role in promoting effective land management. The present study aimed to identify herbaceous species in Parque Urbano das Camélias located in the city of Braga. The research was conducted as part of an ongoing collaboration between the School of Sciences at the University of Minho and the Municipal Council of Braga. The site was sampled using the quadrant method, employing a 1m² measurement, to encompass 12 strategically selected locations throughout the park. The findings encompassed 28 distinct specimens, with identification achieved at the genus level for 27 and at the species level for 25. The study area harbors both native species from mainland Portugal and exotic species, with the Poaceae family being predominant, accounting for 50% of the identified individuals. Some of the species identified in the park include Avena spp., Bromus madritensis, and Plantago lanceolata. The study discusses preservation strategies and biodiversity enhancement for the Parque Urbano das Camélias.

Cellular uptake, biodistribution and protection against oxidative damage by Withania somnifera leaf extract-loaded PCL and MPEG-PCL nanoparticles

Fri, 18 Oct 2024 00:00:00 +0000

Withania somnifera (WS) or Ashwagandha is a well-known medicinal plant, cultivated in dry areas of India and Pakistan, where it represents an important resource as a widely used medicinal crop. Because of its anti-inflammatory and immunomodulatory effects, its extract is used, alone or in combination with other herbal extracts, in the treatment of age-related and neurodegenerative disorders. For tapping on the important therapeutic potential of this resource for biomedicine, strategies for controlled delivery and biodistribution improvement are necessary to guarantee treatment efficacy. Pharmacological properties of WS leaf extract (WSE) are mainly attributed to the presence of withanolides. In the present study, WSE was encapsulated in nanoparticles composed of biodegradable polymers as poly-ε-caprolactone (PCL) and methoxy poly-ethylene glycol poly-ε-caprolactone (MPEG-PCL) di-block copolymer. Laser doppler anemometry (LDA), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) were used to analyze their size and shape. The particle size distribution of WSE-loaded PCL and MPEG-PCL nanoparticles was measured as 214-268 and 30-62 nm, respectively, presenting in both cases a spherical shape. U251 glioma cells, representative of the most common and lethal type of intracranial tumor which is glioblastoma, were exposed to these nanoparticles, demonstrating their efficient uptake. It was showed that MPEG-PCL nanoparticles containing WSE offered better protection to U251 cells against tert-butyl hydroperoxide (tBHP)-induced oxidative damage (95.1%), compared to PCL nanoparticles with WSE (56.4%) and free WSE (39.0%). In vivo distribution of these nanoparticles was further analyzed using zebrafish embryos to validate their biocompatibility in a relevant vertebrate neurodevelopment model.

Breaking Boundaries in Malaria Research: Design of a Genetic Tool for High-Throughput Gametocidal Drug Screening

Wed, 17 Apr 2024 00:00:00 +0000

Malaria, a devastating illness remains a global health concern with an estimated 249 million malaria cases in 85 malaria-endemic countries around the world. Malaria elimination, challenged by drug resistance, requires strategic interventions that could be the implementation of antimalarials with selective actions on the different phases of the parasite life cycle. Of particular relevance is gametocytocidal drugs that could be used to prevent transmission of malaria infection to the mosquito.

Finding drugs with gametocidal effect thus are limited by the technical challenges of large-scale production and quantification of parasite transmission stage, gametocytes. To surmount these obstacles, our study endeavors to design a genetic engineering strategy (a vector construct) to further deliver nucleic acid information through transfections-based systems in the form of a plasmid into Plasmodium falciparum. This approach will enable us to engineer a transgenic parasite line for multi-stage drug screening, targeting the symptomatic intra-erythrocyte parasite stage and gametocytes.

Genetic engineering tools such as selected linked integration system and attB-attP site-specific recombination will be used in our vector construct aiming the genetic integration process into the P. falciparum genome. These systems will accommodate strategies for easy and accurate stage-specific quantification such as RFP-luciferase fusion cloned downstream stage-specific promoters leading to reporter products with optical outputs and for efficient production of gametocytes at large scale using a riboswitch-based inducible gene expression system. Such technology is of major need and will pave the way for scaling up the capacity for high-throughput drug screening, leading to improved strategies to find drugs capable of blocking malaria transmission.