Full spectral fitting of Milky Way and M31 globular clusters: ages and metallicities

Context: The formation and evolution of disk galaxies are long standing questions in Astronomy. Understanding the properties of globular cluster systems can lead to important insights on the evolution of its host galaxy. Aims: We aim to obtain the stellar population parameters - age and metallicity - of a sample of M31 and Galactic globular clusters. Studying their globular cluster systems is an important step towards understanding their formation and evolution in a complete way. Methods: Our analysis employs a modern pixel-to-pixel spectral fitting technique to fit observed integrated spectra to updated stellar population models. By comparing observations to models we obtain the ages and metallicities of their stellar populations. We apply this technique to a sample of 38 globular clusters in M31 and to 41 Galactic globular clusters, used as a control sample. Results: Our sample of M31 globular clusters spans ages from 150 Myr to the age of the Universe. Metallicities [Fe/H] range from -2.2 dex to the solar value. The age-metallicity relation obtained can be described as having two components: an old population with a flat age-[Fe/H] relation, possibly associated with the halo and/or bulge, and a second one with a roughly linear relation between age and metallicity, higher metallicities corresponding to younger ages, possibly associated with the M31 disk. While we recover the very well known Galactic GC metallicity bimodality, our own analysis of M31's metallicity distribution function (MDF) suggests that both GC systems cover basically the same [Fe/H] range yet M31's MDF is not clearly bimodal. These results suggest that both galaxies experienced different star formation and accretion histories.Comment: A&A, in pres

Antileishmanial activity and evaluation of the mechanism of action of strychnobiflavone flavonoid isolated from Strychnos pseudoquina against Leishmania infantum

© 2015, Springer-Verlag Berlin Heidelberg. The present study aimed to investigate the in vitro antileishmanial activity of strychnobiflavone flavonoid against Leishmania infantum, as well as its mechanism of action, and evaluate the ex vivo biodistribution profile of the flavonoid in naive BALB/c mice. The antileishmanial activity (IC50 value) of strychnobiflavone against stationary promastigote and amastigote-like stages of the parasites was of 5.4 and 18.9 μM, respectively; with a 50% cytotoxic concentration (CC50) value of 125.0 μM on murine macrophages, resulting in selectivity index (SI) of 23.2 and 6.6, respectively. Amphotericin B, used as a positive control, presented SI values of 7.6 and 3.3 for promastigote and amastigote-like stages of L. infantum, respectively. The strychnobiflavone was also effective in reducing in significant levels the percentage of infected macrophages, as well as the number of amastigotes per macrophage, after the treatment of infected macrophages using the flavonoid. By using different fluorescent probes, we investigated the bioenergetics metabolism of L. infantum promastigotes and demonstrated that the flavonoid caused the depolarization of the mitochondrial membrane potential, without affecting the production of reactive oxygen species. In addition, using SYTOX® green as a fluorescent probe, the strychnobiflavone demonstrated no interference in plasma membrane permeability. For the ex vivo biodistribution assays, the flavonoid was labeled with technetium-99m and studied in a mouse model by intraperitoneal route. After a single dose administration, the scintigraphic images demonstrated a highest uptake by the liver and spleen of the animals within 60 min, resulting in low concentrations after 24 h. The present study therefore demonstrated, for the first time, the antileishmanial activity of the strychnobiflavone against L. infantum, and suggests that the mitochondria of the parasites may be the possible target organelle. The preferential distribution of this compound into the liver and spleen of the animals could warrant its employ in the treatment of visceral leishmaniasis.This work was supported by grants from Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica (INCT-Nanobiofar), FAPEMIG (CBB-APQ-00819-12), CNPq (APQ-472090/2011-9, APQ- 482976/2012-8, and APQ-488237/2013-0) and São Paulo State Research Fundation (FAPESP 2012/18756-1). MACF is a grant recipient of FAPEMIG/CAPES. EAFC, VNC and AGT are grant recipient of CNPqPeer Reviewe

Stepwise functional evolution in a fungal sugar transporter family

This is a pre-copyedited, author-produced version of an article accepted for publication in Molecular Biology and Evolution following peer review. The version of record Mol Biol Evol (2016) 33 (2): 352-366 is available online at: http://mbe.oxfordjournals.org/content/33/2/352 DOI 10.1093/molbev/msv220."Sugar transport is of the utmost importance for most cells and is important to a wide range of applied fields. However, despite the straightforward in silico assignment of many novel transporters, including sugar porters, to existing families, their exact biological role and evolutionary trajectory often remain unclear, mainly because biochemical characterization of membrane proteins is inherently challenging, but also owing to their uncommonly turbulent evolutionary histories. In addition, many important shifts in membrane carrier function are apparently ancient, which further limits our ability to reconstruct evolutionary trajectories in a reliable manner.Here we circumvented some of these obstacles by examining the relatively recent emergence of a unique family of fungal sugar facilitators, related to drug antiporters. The former transporters, named Ffz, were previously shown to be required for fructophilic metabolism in yeasts. We first exploited the wealth of fungal genomic data available to define a comprehensive but well-delimited family of Ffz-like transporters, showing that they are only present in Dikarya. Subsequently, a combination of phylogenetic analyses and in vivo functional characterization was used to retrace important changes in function, while highlighting the evolutionary events that are most likely to have determined extant distribution of the gene, such as horizontal gene transfers (HGTs). One such HGT event is proposed to have set the stage for the onset of fructophilic metabolism in yeasts, a trait that according to our results may be the metabolic hallmark of approximately one hundred yeast species that thrive in sugar rich environments."info:eu-repo/semantics/publishedVersio

Development and characterization of b-carotene microcapsules composed of starch and protein extract from Amaranth

The 19th Gums & Stabilisers for the Food Industry Conference: Hydrocolloid multifunctionalityStudies that have explored the use of biopolymers of Amaranth as encapsulating materials for bioactive compounds1,2,3 demonstrate that it is possible to isolate and encapsulate bioactive compounds with Amaranth biopolymers. Therefore, the added value of Amaranth can be increased, evidenced and studied through the extraction of its compounds and the formation of microcapsules. The objective of this study was the evaluation of the ability of Amaranth biopolymers to microencapsulate a bioactive compound - -carotene. The microencapsulation was performed by spray drying4, and -carotene was added to the Amaranth (Amaranthus cruentus) starch or protein through a solution prepared at the ratio of 1:10 (polymer:-carotene) in corn oil (1 %). The microcapsules were characterized by mean diameter (volume%), particle size distribution, microcapsules morphology by epifluorescence microscopy, microstructure by scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and by measuring encapsulation efficiency. Microcapsules exhibited an average size of 2.22 ± 1.84 m and 1.55 ± 1.12 m for microcapsules composed of Amaranth protein and Amaranth starch, respectively. The microscopy images of both microcapsules showed good sphericity and presence of fluorescence, which indicates good encapsulation capacity of -carotene. FT-IR results showed no differences between spectra of all samples, which indicates that there was no chemical bonding between the capsules and -carotene, but rather an entrapment of -carotene into starch and protein microparticles. The encapsulation efficiency was 71.29 % and 69.32 % for Amaranth starch and protein microcapsules, respectively. Therefore, it can be concluded that the biopolymers extracted from Amaranth can be considered good encapsulating agents for bioactive compounds, thus valorising their use in food formulations.This study was funded by the CNPQ-Brazil; FCT – Portugal (SFRH/BPD/89992/2012, SFRH/BPD/101181/2014, SFRH/BPD/104712/2014 and IF/00300/2015 fellowships); Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER- 027462); Project UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER- 006684) and Project CICECO-Aveiro Institute of Materials POCI-01-0145-FEDER-007679 (FCT UID/CTM/50011/2013).info:eu-repo/semantics/publishedVersio

Characterization and bioaccessibility of β-carotene encapsulated on microcapsules produced with starch and protein from amaranth grain

Laylla Coelho acknowledges the CNPQ-Brazil for her fellowship (IF/00300/2015). Pedro Silva acknowledges the Foundation for Science and Technology (FCT) for his fellowship (SFRD/BD/130247/2017). FCT is also thanked for the Investigator FCT program (PF) and for the grant ref. SFRH/BPD/104712/2014 (IG). This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of the UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Functionality of the paracoccidioides mating α-pheromone-receptor system

Recent evidence suggests that Paracoccidioides species have the potential to undergo sexual reproduction, although no sexual cycle has been identified either in nature or under laboratory conditions. In the present work we detected low expression levels of the heterothallic MAT loci genes MAT1-1 and MAT1-2, the a-pheromone (PBa) gene, and the a- and apheromone receptor (PREB and PREA) genes in yeast and mycelia forms of several Paracoccidioides isolates. None of the genes were expressed in a mating type dependent manner. Stimulation of P. brasiliensis MAT1-2 strains with the synthetic a pheromone peptide failed to elicit transcriptional activation of MAT1-2, PREB or STE12, suggesting that the strains tested are insensitive to a-pheromone. In order to further evaluate the biological functionality of the pair a-pheromone and its receptor, we took advantage of the heterologous expression of these Paracoccidioides genes in the corresponding S. cerevisiae null mutants. We show that S. cerevisiae strains heterologously expressing PREB respond to Pba pheromone either isolated from Paracoccidioides culture supernatants or in its synthetic form, both by shmoo formation and by growth and cell cycle arrests. This allowed us to conclude that Paracoccidioides species secrete an active a-pheromone into the culture medium that is able to activate its cognate receptor. Moreover, expression of PREB or PBa in the corresponding null mutants of S. cerevisiae restored mating in these non-fertile strains. Taken together, our data demonstrate pheromone signaling activation by the Paracoccidioides a-pheromone through its receptor in this yeast model, which provides novel evidence for the existence of a functional mating signaling system in Paracoccidioides.MHJS and JFM were supported by Fundacão para a Ciência e Tecnologia (FCT) grants. This work was supported by a grant from FCT (PTDC/BIA-MIC/ 108309/2008)

Honey Bee (Apis mellifera L.) Broods: Composition, Technology and Gastronomic Applicability

Honey bee broods (larvae and pupae) can be consumed as human food, offering a rich nutritional value. Therefore, the objective of this work was to present an overview of the nutritional value of the honey bee brood and its gastronomic potential. The results indicated that honey bee broods are rich in protein (including essential amino acids), fat (essentially saturated and monounsaturated fatty acids), carbohydrates, vitamin C and those of the B complex, and minerals such as potassium, magnesium, calcium, and phosphorous. The results further highlight some variability according to the stage of development, with increasing content of fat and protein and decreasing carbohydrates from the larval to the pupal stages. The production of the honey bee brood in the hive, as well as its removal, can impact the wellbeing of the hive. This limits the production potential of the brood aimed at application for gastronomic purposes. The consumption and purchase of honey bee broods as food may be accessible in specialised markets where, for example, ethnic communities consume this type of food. However, in some markets, insects or products produced from insects are not readily accepted because of neophobia and disgust. The role of culinary chefs allied to traditional ways of preparing culinary dishes that include honey bee broods are relevant to motivate more people in western societies to consume of these types of food products.info:eu-repo/semantics/publishedVersio