Abstract Cryptococcus neoformans and Cryptococcus gattii are the etiological agents of cryptococcosis, a high mortality disease. The development of such disease depends on the interaction of fungal cells with macrophages, in which they can reside and replicate. In order to dissect the molecular mechanisms by which cryptococcal cells modulate the activity of macrophages, a genome-scale comparative analysis of transcriptional changes in macrophages exposed to Cryptococcus spp. was conducted. Altered expression of nearly 40 genes was detected in macrophages exposed to cryptococcal cells. The major processes were associated with the mTOR pathway, whose associated genes exhibited decreased expression in macrophages incubated with cryptococcal cells. Phosphorylation of p70S6K and GSK-3β was also decreased in macrophages incubated with fungal cells. In this way, Cryptococci presence could drive the modulation of mTOR pathway in macrophages possibly to increase the survival of the pathogen.

Abstract: Background: Seaweeds must survive in highly competitive environments and thus develop defense strategies that may produce highly diversified antioxidant compounds. Goals: The main objective of this work was to assess the antioxidant activity of green seaweeds. Methods: Six species of ulvophycean chlorophytes were collected during spring/summer, between the Antarctic (Monostroma hariotii, Protomonostroma rosulatum and Ulva hookeriana - formerly as U. bulbosa) and the southwestern Atlantic Ocean (Gayralia brasiliensis, Protomonostroma undulatum and Ulva fasciata). They were then tested for their antioxidant activities using the 2.2-diphenyl-picrylhydrazyl (DPPH) radical scavenging method and by quantification of their phenolic (expressed as gallic acid equivalent - GAE - and carotenoid contents. Results: Among the evaluated species, P. rosulatum and U. hookeriana showed high antioxidant potential (77.9±2.8 and 53.1±15.0%, respectively) and high phenolic content (176±6.0 and 144.7±8.9 µg GAE g-1, respectively). These species were collected on King George Island (South Shetland archipelago, around the Antarctic Peninsula) and their higher antioxidant potential may be associated with adaptation to the high incidence of UV rays in this region during summer. In general, tested seaweeds, mainly the samples collected in the Antarctic and Chilean Patagonia, showed higher values of phenolic (from 58.3±2.0 to 144.7±8.9 µg GAE g-1) and carote noid contents (from 23.4±0.2 to 51.5±0.1 µg β-carotene g-1). Conclusions: The presence and levels of these compounds suggest that the target seaweeds may have high antioxidant potential. Also the antioxidant activity could be associated with the occurrence area of the species instead of the order or taxonomic group to which they belong.

Resumen: Antecedentes: Las algas marinas tienen que sobrevivir en entornos altamente competitivos, lo que hace que desarrollan estrategias de defensa que pueden dar lugar a una gran diversidad de compuestos antioxidantes. Objetivos: El principal objetivo de este trabajo fue evaluar la actividad antioxidante de algas verdes. Métodos: Seis especies de clorófitos (Ulvophyceae) recogidos durante el primavera/verano entre la Antártida (Monostroma hariotii, Protomonostroma rosulatum y Ulva hookeriana - antes como U. bulbosa) y el Atlántico Sur (Gayralia brasiliensis, Protomonostroma undulatum y Ulva fasciata) fueron probados por su actividad antioxidante usando el método de secuestro de radicales libres con 2,2-diphenil-picrylhidrazil (DPPH) y pela cuantificación de contenidos fenólicos (expreso como equivalente de ácido gálico (GAE)) y contenidos de carotenoides. Resultados: Entre las especies evaluadas, P. rosulatum y U. hookeriana mostraron alto potencial antioxidante (77,9±2,8 y 53,1±15%, respectivamente) y alto contenido fenólico (176±6,0 y 144,7±8,9 µg GAE g-1, respectivamente). Estas especies fueron recolectadas en la Isla Rey Jorge (cerca de la Península Antártida) y su mayor potencial antioxidante puede estar asociado con la adaptación a la alta incidencia de los rayos UV en esta región. En general, las algas marinas probadas, principalmente las muestras recogidas en la Patagonia Antártida y chilena, mostraron valores más altos de fenólico (de 58,3 ± 2,0 a 144,7 ± 8,9 mg GAE g-1) y el contenido de carotenoides (de 23,4 ± 0,2 a 51,5 ± 0,1 mg g-1 β-caroteno). Conclusiones: La presencia y los niveles de estos compuestos sugieren que las algas marinas diana pueden tener un alto potencial antioxidante. También la actividad antioxidante podría estar asociada con el área de ocurrencia de las especies en lugar de la orden o grupo taxonómico a la que pertenecen.

Currently, the most successful predictive models for activity coefficients are those based on functional groups such as UNIFAC. In contrast, these models require a large amount of experimental data for the determination of their parameter matrix. A more recent alternative is the models based on COSMO, for which only a small set of universal parameters must be calibrated. In this work, a recalibrated COSMO-SAC model was compared with the UNIFAC (Do) model employing experimental infinite dilution activity coefficient data for 2236 non-hydrogen-bonding binary mixtures at different temperatures. As expected, UNIFAC (Do) presented better overall performance, with a mean absolute error of 0.12 ln-units against 0.22 for our COSMO-SAC implementation. However, in cases involving molecules with several functional groups or when functional groups appear in an unusual way, the deviation for UNIFAC was 0.44 as opposed to 0.20 for COSMO-SAC. These results show that COSMO-SAC provides more reliable predictions for multi-functional or more complex molecules, reaffirming its future prospects.