227 research outputs found
Disease Localization in Multilayer Networks
We present a continuous formulation of epidemic spreading on multilayer
networks using a tensorial representation, extending the models of monoplex
networks to this context. We derive analytical expressions for the epidemic
threshold of the SIS and SIR dynamics, as well as upper and lower bounds for
the disease prevalence in the steady state for the SIS scenario. Using the
quasi-stationary state method we numerically show the existence of disease
localization and the emergence of two or more susceptibility peaks, which are
characterized analytically and numerically through the inverse participation
ratio. Furthermore, when mapping the critical dynamics to an eigenvalue
problem, we observe a characteristic transition in the eigenvalue spectra of
the supra-contact tensor as a function of the ratio of two spreading rates: if
the rate at which the disease spreads within a layer is comparable to the
spreading rate across layers, the individual spectra of each layer merge with
the coupling between layers. Finally, we verified the barrier effect, i.e., for
three-layer configuration, when the layer with the largest eigenvalue is
located at the center of the line, it can effectively act as a barrier to the
disease. The formalism introduced here provides a unifying mathematical
approach to disease contagion in multiplex systems opening new possibilities
for the study of spreading processes.Comment: Revised version. 25 pages and 18 figure
Oxidative stress enzymes and mitochondrial bioenergetics in wild Liza saliens exposed to heavy metals
The Esmoriz-Paramos coastal lagoon represents an ecosystem of great physical and ecological
significance. However, as a result of industrial, agricultural and antropogenic activities this habitat
has been progressively degrading over the last decades. The heavy metal contamination is an
important factor to the decline of sediments quality and may adversely affect fish health. In the
present work the leaping grey mullet Liza saliens was studied because it is the dominant endemic
species in the lagoon. It is a filter feeder and also being a detritus-mud feeder, it is therefore
exposed to contaminated sediments
Fatty acid characterization of cyanobacterial strains isolated from vela lake and mondego river rice fields (central-western, Portugal)
It is know that cyanobacterial taxonomic groups are characterized by particular lipid patterns that can be used as their biological markers.
The present study examined the fatty acid composition of nostocacean heterocystous cyanobacterial strains isolated from Central-western Portuguese
freshwater shallow water bodies, namely Vela Lake and rice fields from Mondego River Basin. Morphological characterization showed that strains from
Vela Lake belonged to Aphanizomenon gracile (strains UADFA16 and UADFA18), Aphanizomenon flos-aquae (strain UADFA15) and Anabaena cf.
solitaria (strain UADFA14) species, whereas rice field strains belonged to Anabaena cylindrica (strain UTAD_A212) and Nostoc muscorum (strain
UTAD_N213). Biochemical characterization inferred from lipid analysis showed that predominant fatty acid methyl esters (FAMEs) in the lipids of the
strains were palmitic, oleic and α-linolenic, with trace amounts of myristic and C20 polyunsaturated FAMEs. To our knowledge, there is almost no
information about lipid composition in freshwater cyanobacterial species living in different habitats in Portugal. Therefore, this limnological study is a
contribution to our investigation on freshwater diazotrophic cyanobacteria
Oxidative stress responses and histological hepatic alterations in barbel, Barbus bocagei, from Vizela river, Portugal
Barbel (Barbus bocagei) a common species in Portuguese rivers was studied to assess the impact of water contamination on hepatic oxidative stress response, lipid peroxidation and histology. The Vizela River is a tributary of the Ave River, located in one of the most industrialized areas of Portugal. The oxidative stress biomarkers analyzed included superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, glucose 6‑phosphate dehydrogenase and xanthine oxidase activities. Levels of reduced glutathione and lipid peroxidation were also evaluated. Except xanthine oxidase activity, that did not show any alteration, all the other enzymatic activities were increased in the liver of barbel captured in the Vizela River when compared with reference barbel. While, no differences were observed for glutathione reductase content, lipid peroxidation was higher in barbel from the Vizela River. Liver histological alterations were determined and their severity scored. Though lymphocyte foci were only observed in Vizela River barbel, macrophage aggregates were also present in reference barbel, although the severity score was higher in Vizela fish. The results of this study show that barbel liver oxidative stress responses, lipid peroxidation and histology are sensitive to the contaminants present in Vizela River water and are valuable biomarkers for monitoring purposes.Barbos (Barbus bocagei), una especie común en los ríos portugueses, se utilizó para evaluar el impacto de la contaminación del agua en la respuesta hepática al estrés oxidativo, en la peroxidación lipídica y en la histología del órgano. El río Vizela es un
afluente del río Ave, situado en una de las regiones más industrializadas de Portugal.
Los biomarcadores de estrés oxidativo analizados fueron la actividad de las enzimas
superóxido dismutasa, catalasa, glutatión S-transferasa, glutation reductasa, glucosa
6 fosfato deshidrogenasa y de la xantina oxidasa. Los niveles de glutatión reducido
y de la peroxidación lipídica también fueron evaluados. Excepto la xantina oxidasa,
que no mostró ninguna alteración, todas las otras actividades enzimáticas han sufrido
incrementos en el hígado de los barbos capturados en el río Vizela, cuando se comparan
con los barbos de referencia. No se observaron diferencias para el contenido
de glutatión reductasa, pero la peroxidación lipídica fue mayor en los barbos del río
Vizela. Las alteraciones en la histología hepática fueron identificadas y clasificadas
de acuerdo con su gravedad. Mientras que los linfocitos de focos se observaron sólo
en barbos del Río Vizela, los agregados de macrófagos también estuvieron presentes
en barbos locales de referencia, aunque la gravedad de las alteraciones fue mayor en
los peces del río Vizela. Los resultados de este estudio muestran que las respuestas de
estrés oxidativo, la peroxidación lipídica y la histología hepática son sensibles a los
contaminantes presentes en el agua del Río Vizela, demonstrando ser biomarcadores
valiosos para propósitos de monitoreo
Occupational pesticide exposure and the risk of death in patients with Parkinson’s disease : an observational study in southern Brazil
Background: Multiple studies have suggested that various pesticides are associated with a higher risk of developing Parkinson’s disease (PD) and may influence the progression of the disease. However, the evidence regarding the impact of pesticide exposure on mortality among patients with PD is equivocal. This study examines whether pesticide exposure influences the risk of mortality among patients with PD in Southern Brazil. Methods: A total of 150 patients with idiopathic PD were enrolled from 2008 to 2013 and followed until 2019. In addition to undergoing a detailed neurologic evaluation, patients completed surveys regarding socioeconomic status and environmental exposures. Results: Twenty patients (13.3%) reported a history of occupational pesticide exposure with a median duration of exposure of 10 years (mean = 13.1, SD = 11.2). Patients with a history of occupational pesticide exposure had higher UPDRS-III scores, though there were no significant differences in regards to age, sex, disease duration, Charlson Comorbidity Index, and age at symptom onset. Patients with occupational pesticide exposure were more than twice as likely to die than their unexposed PD counterparts (HR = 2.32, 95% CI [1.15, 4.66], p = 0.018). Occupational pesticide exposure was also a significant predictor of death in a cox-proportional hazards model which included smoking and caffeine intake history (HR = 2.23, 95% CI [1.09, 4.59], p = 0.03)) and another which included several measures of socioeconomic status (HR = 3.91, 95% CI [1.32, 11.58], p = 0.01). Conclusion: In this prospective cohort study, we found an increased all-cause mortality risk in PD patients with occupational exposure to pesticides. More studies are needed to further analyze this topic with longer follow-up periods, more detailed exposure information, and more specific causes of mortality
Toxicological evaluation of pterospartum tridentatum flower water
Pterospartum tridentatum Willk. (prickled broom) is an autochthonous
plant, common in Portuguese territory.
The yellow flowers are widely used in traditional medicine, as a potential cure for all
body illnesses, mainly for throat irritation treatment or for diabetes, hypertension and
hypercholesterolemia therapy.
Despite its wide traditional use, no toxicological assessment of this plant has been
performed, as far as we know. The major goal of this work was the P. tridentatum water
extracts safety assessment.
Methodology: Chemical characterization of MS analysis of P. tridentatum flower
extract was performed by ESI-MS spectroscopy; phenols and quercetins content were
also determined. Antioxidant activity was evaluated through -carotene bleaching test
and ABTS radical-scavenging activity. Oxygen consumption of isolated mitochondria
was determined polarographically with a Clark oxygen electrode and mitochondrial
respiratory rates evaluated accordingly to Chance and Williams (1956) and
mitochondrial swelling was evaluated the apparent absorbance changes at 520 nm.
Results and discussion: A high antioxidant activity of P. tridentatum flower water
extract was assessed in good agreement with its ESI-MS spectrum that revealed the
presence of several flavonoids, as luteolin-O-(O-acetyl)-glucuronide, luteolin-Oglucuronide
or isorhamnetin-O-hexoside.
Mitocondrial respiratory rates (state 4, state 3 and FCCP-stimulated respiration) and
respiratory indexes (respiratory control and P/O ratios) showed no consistent decrease
of respiratory and phosphorylative efficiencies for the concentrations tested (up to 500
μg.mL-1). In conclusion, for the concentration range commonly used P. tridentatum
flowers usage can be regarded as harmless and trustworthy and due to its great
antioxidant properties it is useful to counteract diabetes mellitus associated diseases
Polyphenols characterization and toxicological evaluation of pterospartum tridentatum leaf water extracts
Pterospartum tridentatum Willk. (prickled broom) is an autochthonous and common plant in Portugal. Leaves and stems are normally used in cooking, to flavour rice, roast meat or hunting animals. Leaves are also used as a condiment in fresh salads and, despite of its traditional use, no toxicological evaluation has been performed.
P. tridentatum leaves aqueous extract ESI-MS spectrum revealed the presence of several luteolin and isorhamnetin derived phenolic compounds, which can be associated to the health benefits claimed for this plant species. Still, P. tridentatum leaves extract (up to 100 µg plant extract.mg-1 protein) stimulated state 4 and FCCP-stimulated liver mitochondria respiratory rates and inhibited the state 3 respiratory rate. Respiratory control ratio was diminished, indicating a decrease in phosphorylative efficiency due to inner mitochondrial membrane induced by P. tridentatum leaves extract. Nevertheless, previous results, cytotoxicity evaluation by MTT assay (50 and 125 µg plant extract) showed no significant decrease on HepG2 cell viability. Overall, the present study suggests that the consumption of P. tridentatum leaves should be regarded as safe
Response, Tolerance and Adaptation to Abiotic Stress of Olive, Grapevine and Chestnut in the Mediterranean Region: Role of Abscisic Acid, Nitric Oxide and MicroRNAs
Polyphenols characterization and toxicological evaluation of pterospartum tridentatum leaf water extracts
Pterospartum tridentatum Willk. (prickled broom) is an autochthonous and common plant in Portugal. Leaves and stems are normally used in cooking, to flavour rice, roast meat or hunting animals. Leaves are also used as a condiment in fresh salads and, despite of its traditional use, no toxicological evaluation has been performed.
P. tridentatum leaves aqueous extract ESI-MS spectrum revealed the presence of several luteolin and isorhamnetin derived phenolic compounds, which can be associated to the health benefits claimed for this plant species. Still, P. tridentatum leaves extract (up to 100 µg plant extract.mg-1 protein) stimulated state 4 and FCCP-stimulated liver mitochondria respiratory rates and inhibited the state 3 respiratory rate. Respiratory control ratio was diminished, indicating a decrease in phosphorylative efficiency due to inner mitochondrial membrane induced by P. tridentatum leaves extract. Nevertheless, previous results, cytotoxicity evaluation by MTT assay (50 and 125 µg plant extract) showed no significant decrease on HepG2 cell viability. Overall, the present study suggests that the consumption of P. tridentatum leaves should be regarded as safe
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