Unravelling the Mechanistic Understanding of Metal Nanoparticle-Induced Reactive Oxygen Species Formation: Insights from a Cu Nanoparticle Study.

Humans can be exposed to engineered and nonintentionally formed metal and metal oxide nanoparticles (Me NPs) in occupational settings, in public transportation areas, or by means of contact with different consumer products. A critical factor in the toxic potency of Me NPs is their ability to induce oxidative stress. It is thus essential to assess the potential reactive oxygen species (ROS) formation properties of Me NPs. A common way to assess the relative extent of ROS formation in vitro is to use fluorescence spectroscopy with the DCFH-DA (2',7'-dichlorofluorescein diacetate) probe, with and without HRP (horseradish peroxidase). However, this method does not provide any information about specific ROS species or reaction mechanisms. This study investigated the possibility of using complementary techniques to obtain more specific information about formed ROS species, both the type and reaction mechanisms. Cu NPs in PBS (phosphate buffered saline) were chosen as a test system to have the simplest (least interference from other components) aqueous solution with a physiologically relevant pH. ROS formation was assessed using fluorescence by means of the DCFH-DA method (information on relative amounts of oxygen radicals without selectivity), the Ghormley's triiodide method using UV-vis spectrophotometry (concentrations of H2O2), and electron paramagnetic resonance with DMPO as the spin-trap agent (information on specific oxygen radicals). This approach elucidates that Cu NPs undergo ROS-generating corrosion reactions, which previously have not been assessed in situ. In the presence of H2O2, and based on the type of oxygen radical formed, it was concluded that released copper participates in Haber-Weiss and/or Fenton reactions rather than in Fenton-like reactions. The new combination of techniques used to determine ROS induced by Me NPs provides a way forward to gain a mechanistic understanding of Me NP-induced ROS formation, which is important for gaining crucial insight into their ability to induce oxidative stress.

Genomic evidence for homoploid hybrid speciation in a marine mammal apex predator.

Hybridization is widespread and constitutes an important source of genetic variability and evolution. In animals, its role in generating novel and independent lineages (hybrid speciation) has been strongly debated, with only a few cases supported by genomic data. The South American fur seal (SAfs) Arctocephalus australis is a marine apex predator of Pacific and Atlantic waters, with a disjunct set of populations in Peru and Northern Chile [Peruvian fur seal (Pfs)] with controversial taxonomic status. We demonstrate, using complete genome and reduced representation sequencing, that the Pfs is a genetically distinct species with an admixed genome that originated from hybridization between the SAfs and the Galapagos fur seal (Arctocephalus galapagoensis) ~400,000 years ago. Our results strongly support the origin of Pfs by homoploid hybrid speciation over alternative introgression scenarios. This study highlights the role of hybridization in promoting species-level biodiversity in large vertebrates.

As trajetórias assistenciais de usuários com obesidade na rede de atenção à saúde de Porto Alegre / The assistential trajectories of users with obesity in the health care network of Porto Alegre

Introdução:Partindo de toda a complexidade envolvida no enfrentamento da obesidade, o objetivo deste estudo foi analisar as trajetórias assistenciais de usuários com obesidade pela Rede de Atenção à Saúde do município de Porto Alegre-RS. Objetivo: analisar as trajetórias assistenciais de usuários com obesidade pela Rede de Atenção à Saúde do município de Porto Alegre-RS. Métodos:Estudo qualitativo e exploratório, com indivíduos que realizaram cirurgia bariátrica pela rede pública e profissionais de saúde, por meio de entrevista semiestruturada. Resultados: A partir da análise de conteúdo, foi possível traçar as trajetórias, destacando todos os pontos de atenção à saúde e profissionais acessados pelos usuários. Evidenciou-se que o cuidado àpessoa com obesidade se encontra fragilizado, ocorrendo em sua maioria em serviços especializados. A cirurgia bariátrica apareceu como uma opção central para o tratamento da obesidade, mesmo antes de se esgotarem outras tentativas de cuidado. Algumas das dificuldades apontadas foram a quase inexistência de equipe multiprofissional e a escassez de outras formas de cuidados. Como potencialidade,destacaram-se a facilidade de acessoe vínculos construídos na AB. Conclusão: Apesar dos avanços, o sistema de saúde brasileiro, em especial a Atenção Primária, ainda carece de melhorias, devendo ser vista não somente como primeiro local de acesso e encaminhamento, mas como ponto principal da rede, onde o usuário tenha suas necessidades reconhecidas.

Introduction: Starting from all the complexity involved in coping with obesity, the objective of this study was to analyze the care trajectories of users with obesity through the Health Care Network in the city of Porto Alegre.Objectives: to analyze the care trajectories of users with obesity through the Health Care Network in the city of Porto Alegre. Methods: Qualitative and exploratory study, with individuals who underwent bariatric surgery through the public network and with a health professional, through semi-structured interview. Results:From the content analysis it was possible to trace the trajectories, highlighting all the points of health care and professionals accessed by the users. It became evident that obesity care is weakened, mostly occurring in specialized services. Bariatric surgery appeared as a central option for the treatment of obesity, even before other attempts at care were exhausted. Some of the difficulties pointed out were the almost inexistence of a multidisciplinary team and the scarcity of other forms of care. As a potentiality, ease of access, service, and connection stood out. Conclusion:Despite the advances, the Brazilian health system, especially Primary Care, still needs improvement, and should be seen not only as the first place of access and referral, but as the main point of the network, where the user has their needs recognized.

Reactive Oxygen Species Formed by Metal and Metal Oxide Nanoparticles in Physiological Media-A Review of Reactions of Importance to Nanotoxicity and Proposal for Categorization.

Diffusely dispersed metal and metal oxide nanoparticles (NPs) can adversely affect living organisms through various mechanisms and exposure routes. One mechanism behind their toxic potency is their ability to generate reactive oxygen species (ROS) directly or indirectly to an extent that depends on the dose, metal speciation, and exposure route. This review provides an overview of the mechanisms of ROS formation associated with metal and metal oxide NPs and proposes a possible way forward for their future categorization. Metal and metal oxide NPs can form ROS via processes related to corrosion, photochemistry, and surface defects, as well as via Fenton, Fenton-like, and Haber-Weiss reactions. Regular ligands such as biomolecules can interact with metallic NP surfaces and influence their properties and thus their capabilities of generating ROS by changing characteristics such as surface charge, surface composition, dissolution behavior, and colloidal stability. Interactions between metallic NPs and cells and their organelles can indirectly induce ROS formation via different biological responses. H2O2 can also be generated by a cell due to inflammation, induced by interactions with metallic NPs or released metal species that can initiate Fenton(-like) and Haber-Weiss reactions forming various radicals. This review discusses these different pathways and, in addition, nano-specific aspects such as shifts in the band gaps of metal oxides and how these shifts at biologically relevant energies (similar to activation energies of biological reactions) can be linked to ROS production and indicate which radical species forms. The influences of kinetic aspects, interactions with biomolecules, solution chemistry (e.g., Cl- and pH), and NP characteristics (e.g., size and surface defects) on ROS mechanisms and formation are discussed. Categorization via four tiers is suggested as a way forward to group metal and metal oxide NPs based on the ROS reaction pathways that they may undergo, an approach that does not include kinetics or environmental variations. The criteria for the four tiers are based on the ability of the metallic NPs to induce Fenton(-like) and Haber-Weiss reactions, corrode, and interact with biomolecules and their surface catalytic properties. The importance of considering kinetic data to improve the proposed categorization is highlighted.

Adsorption of Horseradish Peroxidase on Metallic Nanoparticles: Effects on Reactive Oxygen Species Detection Using 2',7'-Dichlorofluorescin Diacetate.

The fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA) together with the enzyme horseradish peroxidase (HRP) is widely used in nanotoxicology to study acellular reactive oxygen species (ROS) production from nanoparticles (NPs). This study examined whether HRP adsorbs onto NPs of Mn, Ni, and Cu and if this surface process influences the extent of metal release and hence the ROS production measurements using the DCFH assay in phosphate buffered saline (PBS), saline, or Dulbecco's modified Eagle's medium (DMEM). Adsorption of HRP was evident onto all NPs and conditions, except for Mn NPs in PBS. The presence of HRP resulted in an increased release of copper from the Cu NPs in PBS and reduced levels of nickel from the Ni NPs in saline. Both metal ions in solution and the adsorption of HRP onto the NPs can change the activity of HRP and thus influence the ROS results. The effect of HRP on the NP reactivity was shown to be solution chemistry dependent. Most notable was the evident affinity/adsorption of phosphate toward the metal NPs, followed by a reduced adsorption of HRP, the concomitant reduction in released manganese from the Mn NPs, and increased levels of released metals from the Cu NPs in PBS. Minor effects were observed for the Ni NPs. The solution pH should be monitored since the release of metals can change the solution pH and the activity of HRP is known to be pH-dependent. It is furthermore essential that solution pH adjustments are made following the addition of NaOH during diacetyl removal of DCFH-DA. Even though not observed for the given exposure conditions of this study, released metal ions could possibly induce agglomeration or partial denaturation of HRP, which in turn could result in steric hindrance for H2O2 to reach the active site of HRP. This study further emphasizes the influence of HRP on the background kinetics, its solution dependence, and effects on measured ROS signals. Different ways of correcting for the background are highlighted, as this can result in different interpretations of generated results. The results show that adsorption of HRP onto the metal NPs influenced the extent of metal release and may, depending on the investigated system, result in either under- or overestimated ROS signals if used together with the DCFH assay. HRP should hence be used with caution when measuring ROS in the presence of reactive metallic NPs.

Phylogenomic Discordance in the Eared Seals is best explained by Incomplete Lineage Sorting following Explosive Radiation in the Southern Hemisphere.

The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance because of strong gene-tree species tree discordance. Divergence times estimates in the group also vary largely between studies. These uncertainties impeded the understanding of the biogeographical history of the group, such as when and how trans-equatorial dispersal and subsequent speciation events occurred. Here, we used high-coverage genome-wide sequencing for 14 of the 15 species of Otariidae to elucidate the phylogeny of the family and its bearing on the taxonomy and biogeographical history. Despite extreme topological discordance among gene trees, we found a fully supported species tree that agrees with the few well-accepted relationships and establishes monophyly of the genus Arctocephalus. Our data support a relatively recent trans-hemispheric dispersal at the base of a southern clade, which rapidly diversified into six major lineages between 3 and 2.5 Ma. Otaria diverged first, followed by Phocarctos and then four major lineages within Arctocephalus. However, we found Zalophus to be nonmonophyletic, with California (Zalophus californianus) and Steller sea lions (Eumetopias jubatus) grouping closer than the Galapagos sea lion (Zalophus wollebaeki) with evidence for introgression between the two genera. Overall, the high degree of genealogical discordance was best explained by incomplete lineage sorting resulting from quasi-simultaneous speciation within the southern clade with introgresssion playing a subordinate role in explaining the incongruence among and within prior phylogenetic studies of the family. [Hybridization; ILS; phylogenomics; Pleistocene; Pliocene; monophyly.].

ToxTracker Reporter Cell Lines as a Tool for Mechanism-Based (geno)Toxicity Screening of Nanoparticles-Metals, Oxides and Quantum Dots.

The increased use of nanoparticles (NPs) requires efficient testing of their potential toxic effects. A promising approach is to use reporter cell lines to quickly assess the activation of cellular stress response pathways. This study aimed to use the ToxTracker reporter cell lines to investigate (geno)toxicity of various metal- or metal oxide NPs and draw general conclusions on NP-induced effects, in combination with our previous findings. The NPs tested in this study (n = 18) also included quantum dots (QDs) in different sizes. The results showed a large variation in cytotoxicity of the NPs tested. Furthermore, whereas many induced oxidative stress only few activated reporters related to DNA damage. NPs of manganese (Mn and Mn3O4) induced the most remarkable ToxTracker response with activation of reporters for oxidative stress, DNA damage, protein unfolding and p53-related stress. The QDs (CdTe) were highly toxic showing clearly size-dependent effects and calculations suggest surface area as the most relevant dose metric. Of all NPs investigated in this and previous studies the following induce the DNA damage reporter; CuO, Co, CoO, CdTe QDs, Mn, Mn3O4, V2O5, and welding NPs. We suggest that these NPs are of particular concern when considering genotoxicity induced by metal- and metal oxide NPs.

Relação entre imagem corporal, atitudes para transtornos alimentares e estado nutricional em universitárias da área da saúde / Relationship between body image, attitudes towards eating disorders and nutritional status in university students in the health area

RESUMO Objetivo Avaliar a relação entre a insatisfação da imagem corporal, atitudes para transtornos alimentares e o estado nutricional em universitárias da área da saúde. Métodos Estudo descritivo, transversal e quantitativo com 225 universitárias matriculadas em oito cursos da área da saúde. Para obtenção dos dados, utilizaram-se três instrumentos autoaplicáveis: o Body Shape Questionnaire (BSQ), o Eating Attitudes Test (EAT-26) e um questionário construído pelas pesquisadoras contendo os dados autorreferidos de altura, peso atual e peso desejado, curso e idade. O estado nutricional foi estabelecido segundo o cálculo do índice de massa corporal. Para análise dos dados, aplicou-se o teste qui-quadrado de Pearson, adotando-se o nível de significância de 5%. Resultados A média de idade foi de 22,65 anos e a de IMC, de 23,05 kg/m2, estando a maioria das universitárias em eutrofia (69,8%). Quanto ao peso desejado, 74,7% gostariam de pesar menos; dessas, 64,9% eram eutróficas. Conforme o BSQ, 51,1% das universitárias tiveram algum grau de insatisfação corporal, e a prevalência de atitudes indicativas de transtornos alimentares, de acordo com o EAT-26, foi de 21,8%. Houve associação estatisticamente significativa entre: IMC e BSQ (p < 0,001); IMC e EAT-26 (p < 0,005); BSQ e EAT-26 (p < 0,001). Ao relacionar a insatisfação da imagem corporal e atitudes de risco para transtornos alimentares, percebeu-se que 87,75% das universitárias com EAT positivo também apresentaram algum grau de insatisfação corporal. Conclusão Evidenciou-se a existência de relação entre a insatisfação com a imagem corporal, atitudes de risco para transtornos alimentares e estado nutricional de universitárias da área da saúde.

ABSTRACT Objective To evaluate the relationship between body image dissatisfaction, attitudes towards eating disorders and nutritional status in university students of health area. Methods Descriptive, transversal and quantitative study with 225 university students registered in eight health courses. To obtain the data, three self-administered instruments were used: the Body Shape Questionnaire (BSQ), the Eating Attitudes Test (EAT-26), and a questionnaire built by the researchers, containing the self-reported data of height, current and desired weight, course and age. The nutritional status was established according to the calculation of body mass index (BMI). For the data analysis, the Pearson chi-square test was applied, adopting the significance level of 5%. Results The mean age was 22.65 years and the BMI was 23.05 kg/m2, with the majority of university students in eutrophy (69.8%). Regarding the desired weight, 74.7% would like to weigh less, of which 64.9% were eutrophic. According to the BSQ, 51.1% of university students had some degree of body dissatisfaction and the prevalence of attitudes indicative of eating disorders, according to the EAT-26, it was 21.8%. There was a statistically significant association between: BMI and BSQ (p < 0.001); BMI and EAT-26 (p < 0.005); BSQ and EAT-26 (p < 0.001). When correlating the dissatisfaction of body image and attitudes of risk for eating disorders, it is noticed that 87.75% of university students with positive EAT also presented some degree of body dissatisfaction. Conclusion It was evidenced the existence of relation between the body image dissatisfaction, attitudes of risk for eating disorders and nutritional status of university students of health area.