Search

In this study, a Taguchi experimental design was used for optimzing the immobilization of the lipase Eversa® Transform 2.0 (EVS) onto a hybrid support consisting of chitosan (CHI) and agarose (AGA), with glutaraldehyde (GLU) used as the support activator. The biocatalyst obtained was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TGA), Energy Dispersive Spectroscopy (EDS), and Scanning Electron Microscopy (SEM). The optimized reaction conditions (60 min, 5 mM ionic strength, 1% GLU concentration, and 5 mg protein load per g of support) resulted in a highly active biocatalyst (74.39 ± 0.48 U/g) and delivered an immobilization yield of 74.20 ± 0.28%. The biocatalyst produced was observed to lose only 15.3% of its activity after 61 days of storage. The activity was also observed to increase by 96.70% ± 0.76, 27.34% ± 2.34, and 84.35% ± 1.68 in the presence of the organic solvents hexane, cyclohexane, and methanol, respectively. Additionally, the byocatalist showed more pronounced activity at temperatures above 50 °C and was still able to retain approximately 30% of it at 70 °C. These values were found to be higher at alkaline pHs, as the activity of Eversa® 2.0 Transform saw an increase of up to 140% at pH 9. The desorption tests performed did not reveal any enzymatic detachment from the support. The novel biocatalyst also showed promising ester-lubricating properties. Furthermore, the in silico study revealed a binding affinity of −5.1 kcal/mol between oleic acid and the enzyme, suggesting that the combination of the substrate and the lipase was more stable and therefore, suitable for esterification. [ABSTRACT FROM AUTHOR]

Kaolin is a mineral composed of hydrated aluminum silicates, clayey and with high bioavailability. The choice of this mineral as immobilization matrix took into account these aspects mentioned above and its high surface area conducive to enzymatic immobilization, containing many OH- binding groups on its surface. Subsequently, the kaolin was functionalized with carboxymethylcellulose and polyethyleneimine (K-CMC-BPEI) and activated with Glutaraldehyde (K-CMC-BPEI-GLU) as a support to immobilize CAL-A. The K-CMC-BPEI-GLU@CAL-A was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TGA), and Scanning Electron Microscopy (SEM). K-CMC-BPEI-GLU@CAL-A, in the temperature range of 50–80 ºC, has a half-life 2–3 times longer than soluble CAL-A, that is, the immobilization process conferred greater stability thermal to the biocatalyst. Furthermore, docking studies showed that the immobilization of CAL-A on the support surface was favorable, since CAL-A has binding affinity to the protein-anchored ligand, estimated at −4.3 to −3.7 kcal/mol. Experiments were performed to verify the catalytic potential of K-CMC-BPEI-GLU@CAL-A at a kinetic resolution of rac -1-(triisopropylsilyl) penta-1,4-diyn-3-ol (1) in an organic medium via an acylation reaction. All experiments yielded the product ((R)- 1 -Ac) with an excellent enantiomeric excess (ee >99%) and enantioselectivity (E > 200). [Display omitted] • Kaolin has been modified with carboxymethylcellulose and polyethyleneimine. • Taguchi method optimizes the immobilization of lipase A from Candida antarctica. • The half-life of CAL-A by 2–3 times over the temperature range 50 – 80 °C. • Molecular coupling was conducted to the interaction between glutaraldehyde /enzyme. • The kinetic resolution of rac-1-(triisopropylsilyl)penta-1,4-diyn-3-ol was studied. [ABSTRACT FROM AUTHOR]

Although several studies have been reported for Pt55 and Au55 nanoclusters, our atomistic understanding of the interplay between the adsorbate-surface interactions and the mechanisms that lead to the formation of the distorted reduced core (DRC) structures, instead of the icosahedron (ICO) structure in gas phase, is still far from satisfactory. Here, we report a density functional theory (DFT) investigation of the role of the adsorption effects of PH3 (one lone pair of electrons) and SH2 (two lone pairs) on the relative stability of the Pt55 and Au55 nanoclusters. In gas phase, we found that the DRC structures with 7 and 9 atoms in the core region are about 5.34 eV (Pt55) and 2.20 eV (Au55) lower in energy than the ICO model with Ih symmetry and 13 atoms in the core region. However, the stability of the ICO structure increases by increasing the number of adsorbed molecules from 1 to 18, in which both DRC and ICO structures are nearly degenerate in energy at the limit of 18 ligands, which can be explained as follows. In gas phase, there is a strong compression of the cationic core region by the anionic surface atoms induced by the attractive Coulomb interactions (core+-surface-), and hence, the strain release is obtained by reducing the number of atoms in the cationic core region, which leads to the 55 atoms distorted reduced core structures. Thus, the Coulomb interactions between the core+ and surface- contribute to break the symmetry in the ICO55 structure. On the other hand, the addition of ligands on the anionic surface reduces the charge transfer between the core and surface, which contributes to decrease the Coulomb interactions and the strain on the core region of the ICO structure, and hence, it stabilizes a compact ICO structure. The same conclusion is obtained by adding van der Waals corrections to the plain DFT calculations. Similar results are obtained by the addition of steric effects, which are considered through the adsorption of triphenylphosphine (PPh3) molecules on Au55, in which the relative stability between ICO and DRC is the same as for PH3 and SH2. However, for Pt55, we found an inversion of stability due to the PPh3 ligand effects, where ICO has higher stability than DRC by 2.40 eV. Our insights are supported by several structural, electronic, and energetic analyses. [ABSTRACT FROM AUTHOR]

The highland endemic frog Bokermannohyla saxicola occurs within the Espinhaço Range, the most extensive and continuous orogenic belt of the Brazilian territory, located in southeastern Brazil. We used mitochondrial DNA markers to test for spatial structure, to investigate the likely influence of past vicariant events, to evaluate demographic dynamics along the species range, and to understand the role of habitat discontinuities in promoting connectivity and diversity along the range. We found four major monophyletic lineages, each one associated with distinct mountain tops. The divergence time found between the four main clades clearly pre-dated the Pleistocene, except for the most recent separation. We observed no signs of population expansion for most of the sampling sites along the range, and a higher genetic diversity in the most continuous and central highland plateau, compared to smaller marginal regions. The Espinhaço Range harbors four deeply divergent lineages of B. saxicola within areas restricted by barriers for millions of years. These relatively isolated populations were kept apart by discontinuities represented by lowland habitats between mountain tops. Most of the lineage divergences occurred earlier than the Pleistocene, thus they cannot be solely explained by climatic oscillations of this epoch. However, within-lineage divergence times were all dated from the Pleistocene, suggesting an important effect in population dynamics. We also suggest that some marginal populations like those from Serra Negra and Serra de Itacambira can be the result of recent colonization events. Finally, in the southern Espinhaço region, the most continuous central highland area shows greater genetic diversity than the marginal discontinuous areas, where we have also observed a significant correlation between genetic and geographic distances. Bokermannohyla saxicola is a good model to study the biogeography of the Espinhaço Range because its high genetic structure reflects ancient as well as recent geological/climatic events, with important implications for conservation. [ABSTRACT FROM AUTHOR]

Abstract: Two species of Suiriri (Aves: Tyrannidae) inhabit semi‐open habitats in South America: the polytypic Suiriri Flycatcher (S. suiriri) and the monotypic Chapada Flycatcher (S. affinis). The phylogenetic relationship between these congeneric species has never been investigated in detail. Here we used molecular tools—three nuclear introns and two mitochondrial genes—to investigate the systematic position of the Chapada Flycatcher, comparing the results found with morphological and behavioral data. We found that the polytypic Suiriri Flycatcher to be monophyletic and that it is included in a clade of Elaeniini flycatchers including Phyllomyias, Phaeomyias, and Capsiempis among other genera. The Chapada Flycatcher, on the other hand, is a member of the Fluvicolini, sister to Sublegatus, and should be allocated on its own monospecific genus, which we herein describe. We suggest that social mimicry is responsible for the remarkable convergence in size, shape, plumage coloration, and behavior in the adults of the Suiriri Flycatcher and the Chapada Flycatcher. [ABSTRACT FROM AUTHOR]

The article offers information on the new and reconfirmed birds from Bertioga, coastal São Paulo state in Brazil. It presents a catalogue of an overlooked and important bird collection prepared by Emílio Dente. The species discussed include Ferruginous Pygmy-Owl Glaucidium brasilianum, Hooded Berryeater Carpornis cucullata, and Sooty Tyrannulet Serpophaga nigricans.

We report a density functional theory investigation of the adsorption properties of CO, NO, and OH on the Cu13, Pt7Cu6, and Pt13 clusters in the cationic, neutral, and anionic states with the aim to improve our atomistic understanding of the adsorption properties on bimetallic clusters compared with monometallic clusters. The adsorption energy of CO and NO are substantially stronger on Pt13 than on Cu13, and hence, CO and NO bind preferentially on Pt sites on Pt7Cu6. Thus, it can contribute to drive the migration of the Pt atoms from the core to the surface region in large PtCu nanoalloys. The CO and NO adsorption energies on the bimetallic cluster are enhanced by a few percent compared with the energies of the monometallic clusters, which shows that the Pt-Cu interaction can contribute to an increase in the adsorption energy. In contrast with CO and NO trends, the OH adsorption energies on Cu13, Pt7Cu6, and Pt13 deviates only up to 0.31 eV, and hence, there is no clear preference for Cu or Pt sites on Pt7Cu6 or an enhancement of the adsorption energy on the bimetallic systems. We found a reduction of the CO and NO vibrational frequencies upon adsorption, which indicates a weakening of the CO and NO binding energies, and it is supported by a slight increase in the bond lengths. However, the OH vibrational frequency increases upon adsorption, which indicates an enhancement of the OH binding energy, which is supported by a slight decrease in the bond length by about 0.01 Å. It can be explained by the large charge transfer from the clusters to the O atom, which enhances the electrostatic interaction in the O-H bonding. [ABSTRACT FROM AUTHOR]

This article aspires to discuss the social democratic control present in the Public Policy for Social Assistance, an essential debate in Social Policies in Brazil. Furthermore, we approach the importance of highlighting the role of councils of Social Welfare and the process of constitution of the public sphere, emphasizing the role of social assistance entities and analyzing the concept of civil society within the framework of guaranteeing rights in a participatory democracy. We use as methodology a theoretical analysis literature review of authors who study and discuss such themes, from the theoretical Marxist and Gramscian perspectives. [ABSTRACT FROM AUTHOR]

In this study, we verified the power of DNA barcodes to discriminate Neotropical birds using Bayesian tree reconstructions of a total of 7404 COI sequences from 1521 species, including 55 Brazilian species with no previous barcode data. We found that 10.4% of species were nonmonophyletic, most likely due to inaccurate taxonomy, incomplete lineage sorting or hybridization. At least 0.5% of the sequences (2.5% of the sampled species) retrieved from GenBank were associated with database errors (poor-quality sequences, Nu MTs, misidentification or unnoticed hybridization). Paraphyletic species (5.8% of the total) can be related to rapid speciation events leading to nonreciprocal monophyly between recently diverged sister species, or to absence of synapomorphies in the small COI region analysed. We also performed two series of genetic distance calculations under the K2P model for intraspecific and interspecific comparisons: the first included all COI sequences, and the second included only monophyletic taxa observed in the Bayesian trees. As expected, the mean and median pairwise distances were smaller for intraspecific than for interspecific comparisons. However, there was no precise 'barcode gap', which was shown to be larger in the monophyletic taxon data set than for the data from all species, as expected. Our results indicated that although database errors may explain some of the difficulties in the species discrimination of Neotropical birds, distance-based barcode assignment may also be compromised because of the high diversity of bird species and more complex speciation events in the Neotropics. [ABSTRACT FROM AUTHOR]

Knowledge of the role of Neotropical montane landscapes in shaping genetic connectivity and local adaptation is essential for understanding the evolutionary processes that have shaped the extraordinary species diversity in these regions. In the present study, we examined the landscape genetics, estimated genetic diversity, and explored genetic relationships with morphological variability and reproductive strategies in seven natural populations of Cattleya liliputana (Orchidaceae). Nuclear microsatellite markers were used for genetic analyses. Spatial Bayesian clustering and population-based analyses revealed significant genetic structuring and high genetic diversity (He = 0.733 ± 0.03). Strong differentiation was found between populations over short spatial scales (FST = 0.138, p < 0.001), reflecting the landscape discontinuity and isolation. Monmonier´s maximum difference algorithm, Bayesian analysis on STRUCTURE and principal component analysis identified one major genetic discontinuity between populations. Divergent genetic groups showed phenotypic divergence in flower traits and reproductive strategies. Increased sexual reproductive effort was associated with rock outcrop type and may be a response to adverse conditions for growth and vegetative reproduction. Here we discuss the effect of restricted gene flow, local adaptation and phenotypic plasticity as drivers of population differentiation in Neotropical montane rock outcrops. [ABSTRACT FROM AUTHOR]

Binary transition-metal clusters have attracted great attention and a large number of studies have been reported, however, our atomistic understanding of the structural formation mechanisms of those clusters is still far from satisfactory. In this paper, we report a systematic study of the Pt n Cu m − n clusters ( m = 2 , 3 , … , 14 , n = 0 , 1 , … , m ) employing Ab-Initio density functional theory calculations within the Perdew–Burke–Ernzerhof functional. Using a set of structural design principles, we obtained a hierarchical set of atomic configurations from which the structural formation mechanisms are discussed in details. We found a negative excess energy for m > 2 , providing strong evidence favouring the formation of binary PtCu clusters. In general, the Cu atoms tend to form agglomerates located near the center of gravity of the clusters while the Pt atoms tend to lie further away from the center of gravity and separated from each other. Therefore, this behaviour tends to reduce the number of Pt–Pt bonds whereas the number of Cu–Cu and Pt–Cu bonds tends to be maximized. These mechanisms help to release strain energy by means of relaxation of the gas-phase clusters, and the locations of the Cu and Pt atoms suggest that the formation of core–shell like structures starts already in this small size regime. Furthermore, the formation of the PtCu alloy does not lead to changes in the magnetic properties of the clusters in comparison with the parent Pt and Cu clusters. The systematic work presented here provides a basis to understand and tailor the properties of binary cluster. [ABSTRACT FROM AUTHOR]

We review the main biogeographic and phylogenetic hypotheses about the origin and distribution of the endemic birds from Brazilian mountaintops, a heterogeneous group composed of hummingbirds and passerines living in high-altitude open habitats ofcampos rupestres,campos de altitudeandcampos sulinosfrom southern to north-eastern Brazilian mountaintops (Espinhaço Range, Serra do Mar, Serra da Mantiqueira and Serra Geral). Some authors consider that these birds are probably closely related to other species distributed in cooler areas of South America. We used ranges of these birds, spatial pattern and discontinuities in the distribution of phytophysiognomies to determine potential geographic barriers to dispersal and centres of origin and speciation. We reanalysed biogeographical hypotheses regarding the evolution of the endemic birds from Brazilian mountaintops and their habitats in the light of recent phylogenetic reconstructions that included some of these species. The evolutionary histories of the speciesAugastes scutatus,Augastes lumachella,Formicivora grantsaui,Polystictus superciliarisandEmbernagra longicaudaare difficult to assess due to lack of phylogenies that establish their systematic position. ForAsthenes luizae,Asthenes moreirae,Cinclodes pabstiandC. espinhacensis, the phylogenies estimate also their lineage divergence times, which allows for inferences concerning connections between the biota of eastern Brazil, southern South America and the Andean mountains. We also identified 26 lowland regions between the mountains that were potentially barriers to dispersal. Phylogenetic relationships strongly highlight the importance of connecting paths and speciation through the south, especially in the cooler areas in South America. These patterns show that eastern Brazil, southern South America and the central and northern Andes are four important centres of origin and radiation for the endemic birds from the eastern Brazilian mountains. [ABSTRACT FROM PUBLISHER]

The objective was to synthesize halloysite nanotubes loaded with chlorhexidine (HNT/CHX) and evaluate the antimicrobial activity, microhardness, color change, and surface characteristics of an experimental self-curing acrylic resin containing varying concentrations of the synthesized nanomaterial. The characterization of HNT/CHX was carried out by calculating incorporation efficiency, morphological and compositional, chemical and thermal evaluations. SAR disks were made containing 0 %, 3 %, 5 %, and 10 % of HNT/CHX. Specimens (n = 3) were immersed in distilled water and spectral measurements were carried out using UV/Vis spectroscopy to evaluate the release of CHX for up to 50 days. The antimicrobial activity of the composite against Candida albicans and Streptococcus mutans was evaluated by disk-diffusion test. Microhardness, color analyses (ΔE), and surface roughness (Ra) (n = 9) were performed before and after 30 days of immersion. Data were analyzed using ANOVA/Bonferroni. {Results.} The incorporation efficiency of CHX into HNT was of 8.15 %. All test groups showed controlled and cumulative CHX release up to 30 or 50 days. Significant antimicrobial activity was verified against both microorganisms (p < 0.001). After the 30-day immersion period, the 10 % HNT/CHX group showed a significant increase in hardness (p < 0.05) and a progressive color change (p < 0.001). At T0, the 5 % and 10 % groups exhibited Ra values similar to the control group (p > 0.05), while at T30, all groups showed similar roughness values (p > 0.05). {Significance.} The modification of a SAR with HNT/CHX provides antimicrobial effect and controlled release of CHX, however, the immediate surface roughness in the 3 % group was compromised when compared to the control group. • Halloysite nanotubes represent a promising drug release system in Dentistry. • The synthetized HNT/CHX based nanocomposite shows sustained CHX release. • The HNT/CHX based nanocomposite inhibits C. albicans and S. mutans growth. [ABSTRACT FROM AUTHOR]

Several studies have found that the Pt55 nanocluster adopts a distorted reduced core structure, DRC55, in which there are 8-11 atoms in the core and 47-44 atoms in the surface, instead of the compact and high-symmetry icosahedron structure, ICO55, with 13 and 42 atoms in the core and surface, respectively. The DRC structure has also been obtained as the putative global minimum configuration (GMC) for the Zn55 (3d), Cd55 (4d), and Au55 (5d) systems. Thus, the DRC55 structure has been reported only for systems with a large occupation of the d-states, where the effects of the occupation of the valence anti-bonding d-states might play an important role. Can we observe the DRC structure for 55-atom transition-metal systems with non-occupation of the anti-bonding d-states? To address this question, we performed a theoretical investigation of the Y55, Zr55, Nb55, Mo55, Tc55, and Pt55 nanoclusters, employing density functional theory calculations. For the putative GMCs, we found that the Y55 adopts the ICO55 structure, while Nb55 and Mo55 adopt a bulk-like fragment based on the hexagonal close-packed structure and Tc55 adopts a face-centered cubic fragment; however, Zr55 adopts a DRC55 structure, like Zn55, Cd55, Pt55, and Au55. Thus we can conclude that the preference for DRC55 structure is not related to the occupation of the anti-bonding d-states, but to a different effect, in fact, a combination of structural and electronic effects. Furthermore, we obtained that the binding energy per atom follows the occupation of the bonding and anti-bonding model, i.e., the stability of the studied systems increases from Y to Tc with a small oscillation for Mo, which also explains the equilibrium bond lengths. We obtained a larger magnetic moment for Y55 (31 μB) which can be explained by the localization of the d-states in Y at nanoscale, which is not observed for the remaining systems (0-1 μB). [ABSTRACT FROM AUTHOR]

Several studies have found that the Pt55 nanocluster adopts a distorted reduced core structure, DRC55, in which there are 8-11 atoms in the core and 47-44 atoms in the surface, instead of the compact and high-symmetry icosahedron structure, ICO55, with 13 and 42 atoms in the core and surface, respectively. The DRC structure has also been obtained as the putative global minimum configuration (GMC) for the Zn55 (3d), Cd55 (4d), and Au55 (5d) systems. Thus, the DRC55 structure has been reported only for systems with a large occupation of the d-states, where the effects of the occupation of the valence anti-bonding d-states might play an important role. Can we observe the DRC structure for 55-atom transition-metal systems with non-occupation of the anti-bonding d-states ? To address this question, we performed a theoretical investigation of the Y55, Zr55, Nb55, Mo55, Tc55, and Pt55 nanoclusters, employing density functional theory calculations. For the putative GMCs, we found that the Y55 adopts the ICO55 structure, while Nb55 and Mo55 adopt a bulk-like fragment based on the hexagonal close-packed structure and Tc55 adopts a face-centered cubic fragment; however, Zr55 adopts a DRC55 structure, like Zn55, Cd55, Pt55, and Au55. Thus we can conclude that the preference for DRC55 structure is not related to the occupation of the anti-bonding d-states, but to a different effect, in fact, a combination of structural and electronic effects. Furthermore, we obtained that the binding energy per atom follows the occupation of the bonding and anti-bonding model, i.e., the stability of the studied systems increases from Y to Tc with a small oscillation for Mo, which also explains the equilibrium bond lengths. We obtained a larger magnetic moment for Y55 (31 μB) which can be explained by the localization of the d-states in Y at nanoscale, which is not observed for the remaining systems (0-1 μB). [ABSTRACT FROM AUTHOR]

Cardanol, principal constituent of the technical cashew nut shell liquid, has applications as antioxidant and antibacterial, and these properties may be enhanced through encapsulation. In the present study, we isolated and purified cardanol, and nanoparticles (NPs) were produced by polyelectrolyte complexation using polysaccharide systems with chitosan, sodium alginate, and non-toxic Arabic gum, because they are biocompatible, biodegradable, and stable. We characterized the NPs for morphological, physicochemical, and antioxidant activity. The micrographs obtained revealed spherical and nanometric morphology, with 70% of the distribution ranging from 34 to 300 nm, presenting a bimodal distribution. The study of the spectra in the infrared region suggested the existence of physicochemical interactions and cross-links between the biopolymers involved in the encapsulated NPs. Furthermore, the NPs showed better antioxidant potential when compared to pure cardanol. Thus, the encapsulation of cardanol may be an effective method to maintain its properties, promote better protection of the active ingredient, minimize side effects, and can target its activities in specific locations, by inhibiting free radicals in various sectors such as pharmaceutical, nutraceutical, and biomedical. [ABSTRACT FROM AUTHOR]

Transition-metal (TM) nanoparticles supported on oxides or carbon black have attracted much attention as potential catalysts for ethanol steam reforming reactions for hydrogen production. To improve the performance of nanocatalysts, a fundamental understanding of the interaction mechanism between water and ethanol with finite TM particles is required. In this article, we employed first-principles density functional theory with van der Waals (vdW) corrections to investigate the interaction of ethanol and water with TM13 clusters, where TM = Ni, Cu, Pd, Ag, Pt, and Au. We found that both water and ethanol bind via the anionic O atom to onefold TM sites, while at higher-energy structures, ethanol binds also via the H atom from the CH2 group to the TM sites, which can play an important role at real catalysts. The putative global minimum TM13 configurations are only slightly affected upon the adsorption of water or ethanol; however, for few systems, the compact higher-energy icosahedron structure changes its configuration upon ethanol or water adsorption. That is, those configurations are only shallow local minimums in the phase space. Except few deviations, we found similar trends for the magnitude of the adsorption energies of water and ethanol, that is, Ni13 > Pt13 > Pd13 and Cu13 > Au13 > Ag13, which is enhanced by the addition of the vdW correction (i.e., from 4% to 62%); however, the trend is the same. We found that the magnitude of the adsorption energy increases by shifting the center of gravity of the d-states toward the highest occupied molecular orbital. On the basis of the Mulliken and Hirshfeld charge analysis, as well as electron density differences, we identified the location of the charge redistribution and a tiny charge transfer (from 0.01 e to 0.19 e) from the molecules to the TM13 clusters. Our vibrational analysis indicates the red shifts in the OH modes upon binding of both water and ethanol molecules to the TM13 clusters, suggesting a weakening of the O-H bonding. [ABSTRACT FROM AUTHOR]

One of the unresolved issues in the ecology of parasites is the relationship between host specificity and performance. Previous studies tested this relationship in different systems and obtained all possible outcomes. This led to the proposal of two hypotheses to explain conflicting results: the trade-off and resource breadth hypotheses, which are treated as mutually exclusive in the literature and were corroborated by different studies. In the present study, we used an extensive database on avian malaria from Brazil and combined analyses based on specificity indices and network theory, in order to test which of those hypotheses might best explain our model system. Contrary to our expectations, there was no correlation between specificity and prevalence, which contradicts both hypotheses. In addition, we detected a strong modular structure in our host–parasite network and found that its modules were not composed of geographically close, but of phylogenetically close, host species. Based on our results, we reached the conclusion that trade-off and resource breadth hypotheses are not really mutually exclusive. As a conceptual solution we propose “The Integrative Hypothesis of Parasite Specialization”, a novel theoretical model that explains the contradictory results found in our study and reported to date in the literature. [ABSTRACT FROM AUTHOR]

This study revealed the potential of magnesium whitlockite [WH: Ca 18 Mg 2 (HPO 4) 2 (PO 4) 12 ] nanoparticles (WH NPs) for anti-inflammatory and anti-cancer therapies. Although magnesium whitlockite possesses promising biological properties, its effects on inflammation and cancer remain unexplored. In this study, we address this gap by synthesizing WH NPs and demonstrating their multifaceted functionalities. Through detailed characterization, we revealed the synthesis pathway involving brushite as a precursor, with magnesium ions incorporated during hydrothermal treatment. WH NPs exhibited anti-inflammatory properties by significantly reducing the production of key inflammatory markers (NO, TNF-α, and IL-6). Furthermore, they display promising anti-cancer activity by inhibiting the proliferation of MDA-MB-231 breast cancer cells. Our findings not only establish a deeper understanding of WH NP synthesis but also highlight their potential for the development of innovative cancer and inflammatory treatments. [Display omitted] • Whithlockite nanoparticles (nWH) were synthesized using a hydrothermal method in 4.5 hours. • nWH reduced the production of inflammatory markers (NO, TNF-α, and IL-6). • nWH inhibits the proliferation of MDA-MB-231 breast cancer cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Taguchi design-assisted Co-immobilization of Lipase. • Co-immobilization of Lipase A and B from Candida antarctica onto Chitosan (CALA-CALB-CHI). • CALA-CALB-CHI derivative evaluated in the kinetic resolution of halohydrins acetates. • (S)-chlorohydrin 3b produced with 98% ee, conversion of 46% and E > 200. • Molecular docking was performed to elucidate the hydrolysis interaction reaction. In the present communication, the simultaneous co-immobilization by covalent binding of lipase A from Candida antarctica (CALA) and lipase B from Candida antarctica (CALB) in glutaraldehyde (GLU) activated chitosan (CHI) was optimized using the Taguchi method. Under optimized conditions (pH 9, 5 mM, 6:1 (protein load/g of support and 1 h), it was possible to reach 80.00 ± 0.01% for the immobilization yield (IY) and 46.01 ± 0.35 U/g for the activity of the derivative (AtD); in this case, load protein and ionic strength were the only statistically significant parameters and, therefore, those that most influenced the immobilization process. Furthermore, at pH 7, CALA-CALB-CHI had a half-life 2–6 times longer than the mixture of CALA and CALB for a temperature range of 50−80 °C. CALA-CALB showed the highest activity at pH 7, whereas CALA-CALB-CHI, except at pH 7, was more active than the soluble lipase mixture in the pH range (5–9), especially at pH 9. CHI, CHI-GLU, and CALA-CALB-CHI were characterized by X-ray powder diffraction (XRPD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetry (TGA), and Energy Dispersive Spectroscopy (EDS), proving the immobilization of CALA and CALB in chitosan. CALA-CALB-CHI derivative evaluated in the kinetic resolution of halohydrins acetates rac -2-bromo-1-(2-chlorophenyl) ethyl acetate (2a) and rac -2-chloro-1-(2,4-dichlorophenyl) ethyl acetate (2b), to produce the corresponding halohydrins 3a-b , which are intermediates in the synthesis of the drugs chlorprelanine (antiarrhythmic) and luliconazol (antifungal), respectively. (S)-bromohydrin 3a was obtained with 79% enantiomeric excess (ee), whereas (S)-chlorohydrin 3b produced with 98% ee , conversion of 46% and E > 200. Additionally, molecular docking was performed to elucidate the hydrolysis interaction reaction between β-halohydrin acetates and lipases CALA-CALB. [ABSTRACT FROM AUTHOR]

Background: One of the most important drawbacks in visceral leishmaniasis (VL) population studies is the difficulty of diagnosing asymptomatic carriers. The aim of this study, conducted in an urban area in the Southeast of Brazil, was to evaluate the performance of serology to identify asymptomatic VL infection in participants selected from a cohort with a two-year follow-up period. Methodology: Blood samples were collected in 2001 from 136 cohort participants (97 positive and 39 negatives, PCR/hybridization carried out in 1999). They were clinically evaluated and none had progressed to disease from their asymptomatic state. As controls, blood samples from 22 control individuals and 8 patients with kala-azar were collected. Two molecular biology techniques (reference tests) were performed: PCR with Leishmania-generic primer followed by hybridization using L. infantum probe, and PCR with specific primer to L. donovani complex. Plasma samples were tested by ELISA using three different antigens: L. infantum and L. amazonensis crude antigens, and rK39 recombinant protein. Accuracy of the serological tests was evaluated using sensitivity, specificity, likelihood ratio and ROC curve. Findings: The presence of Leishmania was confirmed, by molecular techniques, in all kala-azar patients and in 117 (86%) of the 136 cohort participants. Kala-azar patients showed high reactivity in ELISAs, whereas asymptomatic individuals presented low reactivity against the antigens tested. When compared to molecular techniques, the L. amazonensis and L. infantum antigens showed higher sensitivity (49.6% and 41.0%, respectively) than rK39 (26.5%); however, the specificity of rK39 was higher (73.7%) than L. amazonensis (52.6%) and L. infantum antigens (36.8%). Moreover, there was low agreement among the different antigens used (kappa<0.10). Conclusions: Serological tests were inaccurate for diagnosing asymptomatic infections compared to molecular methods; this could lead to misclassification bias in population studies. Therefore, studies which have used serological assays to estimate prevalence, to evaluate intervention programs or to identify risk factors for Leishmania infection, may have had their results compromised. Author Summary: Visceral leishmaniasis or kala-azar in Brazil, caused by a parasite protozoon, is transmitted to humans by sandflies and has wild and domestic dogs as reservoirs. The disease can become chronic, characterized by fever, weight loss, and enlargement of the liver and spleen. However, the infection in humans can be asymptomatic, and the importance of this phase is unknown. The low levels of immune response and the small number of circulating parasites in the blood are the main problems in identifying the asymptomatic phase. In this study we evaluated the performance of the serology tests compared with molecular tests to identify asymptomatic infection in individuals identified in an urban area of Brazil. Also included were non-infected individuals (healthy controls) and patients (diseased controls). Blood was collected and examined by different serological methods and compared with molecular techniques. The presence of the parasite was confirmed by all molecular techniques and should be the method used to identify true infection. The serology methods showed low sensitivity in detecting the infection. We concluded that the serologic methods are inaccurate in identifying asymptomatic infection when compared to molecular techniques and could underestimate the infection in population studies. [ABSTRACT FROM AUTHOR]

Background: One of the most important drawbacks in visceral leishmaniasis (VL) population studies is the difficulty of diagnosing asymptomatic carriers. The aim of this study, conducted in an urban area in the Southeast of Brazil, was to evaluate the performance of serology to identify asymptomatic VL infection in participants selected from a cohort with a two-year follow-up period. Methodology: Blood samples were collected in 2001 from 136 cohort participants (97 positive and 39 negatives, PCR/ hybridization carried out in 1999). They were clinically evaluated and nonehad progressed to disease from their asymptomatic state. As controls, blood samples from 22 control individuals and 8 patients with kala-azar were collected. Two molecular biology techniques (reference tests) were performed: PCR with Leishmania-generic primer followed by hybridization using L. infantum probe, and PCR with specific primer to L. donovani complex. Plasma samples were tested by ELISA using three different antigens: L. infantum and L. amazonensis crude antigens, and rK39 recombinant protein. Accuracy of the serological tests was evaluated using sensitivity, specificity, likelihood ratio and ROC curve. Findings: The presence of Leishmania was confirmed, by molecular techniques, in all kala-azar patients and in 117 (86%) of the 136 cohort participants. Kala-azar patients showed high reactivity in ELISAs, whereas asymptomatic individuals presented low reactivity against the antigens tested. When compared to molecular techniques, the L. amazonensis and L. infantum antigens showed higher sensitivity (49.6% and 41.0%, respectively) than rK39 (26.5%); however, the specificity of rK39 was higher (73.7%) than L. amazonensis (52.6%) and L. infantum antigens (36.8%). Moreover, there was low agreement among the different antigens used (kappa,0.10). Conclusions: Serological tests were inaccurate for diagnosing asymptomatic infections compared to molecular methods;this could lead to misclassification bias in population studies. Therefore, studies which have used serological assays to estimate prevalence, to evaluate intervention programs or to identify risk factors for Leishmania infection, may have had their results compromised. [ABSTRACT FROM AUTHOR]

Abstract In this work we compare solutions of two distinct algorithms that try to increase the value of the algebraic connectivity of a given graph by choosing, with different strategies, edges to be included. Eccentricity and Perturbation Heuristics were considered, as well as random graphs and special families of trees being inputs of those algorithms. As conclusions of the reported experiments, the Eccentricity Heuristic obtains good results when compared with Perturbation Heuristic and a conjecture about broom trees is presented. [ABSTRACT FROM AUTHOR]

An atom-level ab initio understanding of the structural, energetic, and electronic properties of nanoclusters with diameter size from 1 to 2 nm figures as a prerequisite to foster their potential technological applications. However, because of several challenges such as the identification of ground-state structures by experimental and theoretical techniques, our understanding is still far from satisfactory, and further studies are required. We report a systematic ab initio investigation of the 55-atom metal nanoclusters, (M55), including alkaline, transitional, and post-transitional metals, that is, a total of 42 systems. Our calculations are based on all-electron density functional theory within the Perdew-Burke-Ernzerhof (PBE) functional combined with van der Waals (vdW) correction, spin-orbit coupling (SOC) for the valence states. Furthermore, we also investigated the role of the localization of the d states by using the PBE+U functional. We found a strong preference for the putative PBE global-minimum configurations for the compact Mackay icosahedron structure, namely, 16 systems (Na, Mg, K, Sc, Ti, Co, Ni, Cu, Rb, Y, Ag, Cs, Lu, Hf, Re, Hg), while several systems adopt alternative compact structures such as 6 polytetrahedron (Ca, Mn, Fe, Sr, Ba, Tl) and 10 structures derived from crystalline face-centered cubic and hexagonal close-packed (HCP) fragments (Cr, Nb, Mo, Tc, Ru, Rh, Pd, Ta, W, Os). However, the 10 remaining systems adopt less compact structures based on the distorted reduced-core structure (V, Zn, Zr, Cd, In, Pt, Au), tetrahedral-like (Al, Ga), and one HCP wheel-type (Ir) structure. The binding energy shows a quasi-parabolic behavior as a function of the atomic number, and hence the occupation of the bonding and antibonding states defines the main trends (binding energy, equilibrium bond lengths, etc.). On average, the binding energy of the M55 systems represents 79% of the cohesive energy of the respective bulk systems. The addition of the vdW correction changes the putative global-minimum configurations (pGMCs) for selected cases, in particular, for post-transitional metal systems. As expected, the PBE+U functional increases the total magnetic moment, which can be explained by the increased localization of the d states, which also contributed to increase the number of atoms in the core region (increase coordination) of the pGMCs. In contrast with the effects induced by the vdW correction and localization of the d states, the addition of the SOC coupling cannot change the lowest energy configurations, but it affects the electronic properties, as expected from previous calculations for 13-atom clusters. [ABSTRACT FROM AUTHOR]

The bacterial community and genes involved in geobiocycling of arsenic (As) from sediment impacted by long-term gold mining were characterized through culture-based analysis of As-transforming bacteria and metagenomic studies of the arsC, arrA, and aioA genes. Sediment was collected from the historically gold mining impacted Mina stream, located in one of the world’s largest mining regions known as the “Iron Quadrangle”. A total of 123 As-resistant bacteria were recovered from the enrichment cultures, which were phenotypically and genotypically characterized for As-transformation. A diverse As-resistant bacteria community was found through phylogenetic analyses of the 16S rRNA gene. Bacterial isolates were affiliated with Proteobacteria, Firmicutes, and Actinobacteria and were represented by 20 genera. Most were AsV-reducing (72%), whereas AsIII-oxidizing accounted for 20%. Bacteria harboring the arsC gene predominated (85%), followed by aioA (20%) and arrA (7%). Additionally, we identified two novel As-transforming genera, Thermomonas and Pannonibacter. Metagenomic analysis of arsC, aioA, and arrA sequences confirmed the presence of these genes, with arrA sequences being more closely related to uncultured organisms. Evolutionary analyses revealed high genetic similarity between some arsC and aioA sequences obtained from isolates and clone libraries, suggesting that those isolates may represent environmentally important bacteria acting in As speciation. In addition, our findings show that the diversity of arrA genes is wider than earlier described, once none arrA-OTUs were affiliated with known reference strains. Therefore, the molecular diversity of arrA genes is far from being fully explored deserving further attention. [ABSTRACT FROM AUTHOR]

Southeast Brazil is a neotropical region composed of a mosaic of different tropical habitats and mountain chains, which allowed for the formation of bird-rich communities with distinct ecological niches. Although this region has the potential to harbor a remarkable variety of avian parasites, there is a lack of information about the diversity of malarial parasites. We used molecular approaches to characterize the lineage diversity of Plasmodium and Haemoproteus in bird communities from three different habitats in southeast Brazil based on the prevalence, richness and composition of lineages. We observed an overall prevalence of 35.3%, with a local prevalence ranging from 17.2% to 54.8%. Moreover, no significant association between prevalence and habitat type could be verified (p>0.05). We identified 89 Plasmodium and 22 Haemoproteus lineages, with 86% of them described for the first time here, including an unusual infection of a non-columbiform host by a Haemoproteus (Haemoproteus) parasite. The composition analyses of the parasite communities showed that the lineage composition from Brazilian savannah and tropical dry forest was similar, but it was different from the lineage composition of Atlantic rainforest, reflecting the greater likeness of the former habitats with respect to seasonality and forest density. No significant effects of habitat type on lineage richness were observed based on GLM analyses. We also found that sites whose samples had a greater diversity of bird species showed a greater diversity of parasite lineages, providing evidence that areas with high bird richness also have high parasite richness. Our findings point to the importance of the neotropical region (southeast Brazil) as a major reservoir of new haemosporidian lineages. [ABSTRACT FROM AUTHOR]

Premise of the study: Microsatellite primers were developed for the first time in Velloziaceae, in the endangered species Vellozia gigantea. Methods and Results: Using two different protocols, seven primer sets were characterized in three populations of V. gigantea. The primers amplified di- and trinucleotide repeats with six to 12 alleles per locus. These revealed high levels of genetic variation, presenting an average observed heterozygosity of 0.508 in V. gigantea. The seven primers were tested for cross-amplification in three Vellozia species. All primers successfully amplified in V. auriculata. Six primers amplified in V. compacta and three in V. hirsuta. Conclusions: The new marker set described here will be useful for studies of population genetics of V. gigantea. The cross-amplification results indicate the utility of primers for studies in other Vellozia species. [ABSTRACT FROM AUTHOR]

Summary Parrots are one of the most distinct and intriguing groups of birds, with highly expanded brains [ 1 ], highly developed cognitive [ 2 ] and vocal communication [ 3 ] skills, and a long lifespan compared to other similar-sized birds [ 4 ]. Yet the genetic basis of these traits remains largely unidentified. To address this question, we have generated a high-coverage, annotated assembly of the genome of the blue-fronted Amazon (Amazona aestiva) and carried out extensive comparative analyses with 30 other avian species, including 4 additional parrots. We identified several genomic features unique to parrots, including parrot-specific novel genes and parrot-specific modifications to coding and regulatory sequences of existing genes. We also discovered genomic features under strong selection in parrots and other long-lived birds, including genes previously associated with lifespan determination as well as several hundred new candidate genes. These genes support a range of cellular functions, including telomerase activity; DNA damage repair; control of cell proliferation, cancer, and immunity; and anti-oxidative mechanisms. We also identified brain-expressed, parrot-specific paralogs with known functions in neural development or vocal-learning brain circuits. Intriguingly, parrot-specific changes in conserved regulatory sequences were overwhelmingly associated with genes that are linked to cognitive abilities and have undergone similar selection in the human lineage, suggesting convergent evolution. These findings bring novel insights into the genetics and evolution of longevity and cognition, as well as provide novel targets for exploring the mechanistic basis of these traits. Highlights • The blue-fronted Amazon, Amazona aestiva, and other parrots share unique novel genes • Convergent selection in long-lived birds suggests new lifespan-influencing genes • Parrot genomes share genetic changes related to genes critical for brain function • Similar changes in parrot and human genomes suggest convergent evolution of cognition The genetic basis for the complex traits that characterize parrots, including extreme longevity and advanced cognition, remains unknown. Wirthlin et al. present the genome of the blue-fronted Amazon, Amazona aestiva. Comparisons with other birds and humans reveal genomic similarities, suggesting convergent mechanisms in the evolution of these traits. [ABSTRACT FROM AUTHOR]