Time-based distribution of Staphylococcus saprophyticus pulsed field gel-electrophoresis clusters in community-acquired urinary tract infections

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.

Genetic polymorphisms in the glutamate-rich protein of Plasmodium falciparum field isolates from a malaria-endemic area of Brazil

The genetic diversity displayed by Plasmodium falciparum, the most deadly Plasmodium species, is a significant obstacle for effective malaria vaccine development. In this study, we identified genetic polymorphisms in P. falciparum glutamate-rich protein (GLURP), which is currently being tested in clinical trials as a malaria vaccine candidate, from isolates found circulating in the Brazilian Amazon at variable transmission levels. The study was performed using samples collected in 1993 and 2008 from rural villages situated near Porto Velho, in the state of Rondônia. DNA was extracted from 126 P. falciparum-positive thick blood smears using the phenol-chloroform method and subjected to a nested polymerase chain reaction protocol with specific primers against two immunodominant regions of GLURP, R0 and R2. Only one R0 fragment and four variants of the R2 fragment were detected. No differences were observed between the two time points with regard to the frequencies of the fragment variants. Mixed infections were uncommon. Our results demonstrate conservation of GLURP-R0 and limited polymorphic variation of GLURP-R2 in P. falciparum isolates from individuals living in Porto Velho. This is an important finding, as genetic polymorphisms in B and T-cell epitopes could have implications for the immunological properties of the antigen.

Lepidópteros visitantes florais de Stachytarpheta cayennensis (Rich.) Vahl (Verbenaceae) em remanescente de Mata Atlântica, Minas Gerais, Brasil

Foram analisadas a composição e sazonalidade da comunidade de lepidópteros visitantes florais de S. cayennensis na Estação Ambiental de Peti. Registrou-se a visita de 445 lepidópteros pertencentes a 98 espécies, distribuídos em 6 famílias: Hesperiidae (81,8%), Pieridae (10,8%), Lycaenidae (3,6%), Nymphalidae (2,2%), Papilionidae (1,3%) e Sesiidae (0,3%). Os hesperídeos também apresentaram a maior riqueza, com 70 espécies amostradas. Das espécies amostradas, apenas quatro tiveram abundância relativa acima de 5% (Pyrgus orcus (Stoll, 1780), Pompeius pompeius (Latreille, [1824]), Urbanus dorantes dorantes (Stoll, 1790) e Corticea corticea (Plötz, 1882)). De acordo com a classificação de Palma, duas espécies foram comuns, 12 intermediárias e 84 foram consideradas raras. Os valores de diversidade e uniformidade foram altos (H'= 3,98 e E = 0,87). Existe nítida diferença na composição e abundância das espécies ao longo do ano, onde foi observado que a maior riqueza de espécies e número de indivíduos estiveram concentrados na estação chuvosa. A similaridade entre as duas estações foi relativamente baixa, 25 ocorreram na estação seca, 93 na chuvosa e apenas 18 ocorreram nas duas estações. Os lepidópteros apresentaram maior atividade de forrageamento em temperaturas entre 23 e 32 ºC, sendo a maior abundância registradas por volta das 10:00 horas.

Compositional and structural variabilities of Mg-rich iron oxide spinels from tuffite

Maghemite (γFe2O3) from tuffite is exceptionally rich in Mg, relatively to most of those reportedly found in other mafic lithosystems. To investigate in detail the compositional and structural variabilities of this natural magnetic iron oxide, sets of crystals were isolated from samples collected at different positions in a tuffite weathering mantle. These sets of crystal were individually powdered and studied by X-ray diffractometry, Mössbauer spectroscopy, magnetization measurements and chemical analysis. Lattice parameter of the cubic cell (a0) was found to vary from 0.834(1) to 0.8412(1) nm. Lower a0-values are characteristic of maghemite whereas higher ones are related to a magnetite precursor. FeO content ranges up to 17 mass % and spontaneous magnetization ranges from 8 to 32 J T-1 kg-1. Zero-field room temperature Mössbauer spectra are rather complex, indicating that the hyperfine field distributions due to Fe3+ and mixed valence Fe3+/2+ overlap. The structural variabilities of the (Mg, Ti)-rich iron oxide spinels is essentially related to the range of chemical composition of its precursor (Mg, Ti)-rich magnetite, and probably to the extent to which it has been oxidized during transformation in soil.

Propriedades e aplicações de clusters trinucleares de carboxilatos de rutênio

A review with 94 references focusing on mu3-oxo-triruthenium carboxylate clusters is presented. The electronic, magnetic, electrochemical, and catalytic properties of these compounds are discussed. Main synthetic routes and structural characteristics, including their use as building blocks in supramolecular systems are described.

Amphotericin B associated with triglyceride-rich nanoemulsion: stability studies and in vitro antifungal activity

Amphotericin B (AB) is the standard drug for invasive fungal infection therapy. It has a broad spectrum of activity and it is the best antifungal available against most yeasts and molds. Its therapeutic use, however, is limited by significant side effects, leading to a low therapeutic index when it is used as the traditional formulation (Fungizone®). Due to self-association, AB can form pores in cholesterol-containing membranes. We propose a triglyceride-rich nanoemulsion as a delivery system for AB in low levels of aggregation to reduce the toxicity against host cells.

Singlet oxygen reactivity in water-rich solvent mixtures

The 3-methylindole (3MI) oxygenation sensitized by psoralen (PSO) has been investigated in 100%, 20% and 5% O2-saturated water/dioxane (H2O/Dx) mixtures. The lowering of the ¹O2* chemical rate when water (k chem∆3MI = 1.4 × 109 M-1 s-1) is replaced by deuterated water (k chem∆3MI = 1.9 × 108 M-1 s-1) suggests that hydrogen abstraction is involved in the rate determining step. A high dependence of the chemical rate constant on water concentration in H2O/Dx mixtures was found showing that water molecules are absolutely essential for the success of the 3MI substrate oxidation by ¹O2* in water-rich solvent mixtures.

Metodologia AGOA: a modelagem de clusters de hidratação no complexo aziridina···ácido fluorídrico

We present a theoretical study of solvent effect on C2H5N···HF hydrogen-bonded complex through the application of the AGOA methodology. By using the TIP4P model to orientate the configuration of water molecules, the hydration clusters generated by AGOA were obtained through the analysis of the molecular electrostatic potential (MEP) of solute (C2H5N···HF). Thereby, it was calculated the hydration energies on positive and negative MEP fields, which are maxima (PEMmax) and minima (PEMmin) when represent the -CH2- methylene groups and hydrofluoric acid, respectively. By taking into account the higher and lower hydration energy values of -370.6 kJ mol-1 and -74.3 kJ mol-1 for PEMmax and PEMmin of the C2H5N···HF, our analysis shows that these results corroborate the open ring reaction of aziridine, in which the preferential attack of water molecules occurs at the methylene groups of this heterocyclic.

Interação de átomos leves com clusters de metais de transição

Density Functional Theory (DFT) calculations on the interactions of small atoms (H, C, O, and S) on first-row transition metal clusters were performed. The results show that the adsorption site may vary between the metal surface and the edge of the cluster. The adsorption energies, adatom-nearest neighbor and adatom-metal plane distances were also determined. Finally, the authors present a discussion about the performance of these metals as anodes on solid oxide fuel cells. The results obtained agree with empirical data, indicating that the theoretical model used is adequate

The use of Rich and Suter diagrams to explain the electron configurations of transition elements

Rich and Suter diagrams are a very useful tool to explain the electron configurations of all transition elements, and in particular, the s¹ and s0 configurations of the elements Cr, Cu, Nb, Mo, Ru, Rh, Pd, Ag, and Pt. The application of these diagrams to the inner transition elements also explains the electron configurations of lanthanoids and actinoids, except for Ce, Pa, U, Np, and Cm, whose electron configurations are indeed very special because they are a mixture of several configurations.

Dft theoretical study of energetic nitrogen-rich C4N6H8-n(NO2)n derivatives

Density functional theory (DFT) calculations at the B3LYP/6-31G** theoretical level were performed for a series of guanidine-fused bicyclic skeleton derivatives C4N6H8-n(NO2)n (n = 1 - 6). The heats of formation (HOFs) were calculated by isodesmic reactions, and the detonation properties were evaluated using the Kamlet - Jacobs equations. The bond dissociation energies were also analyzed to investigate the thermal stability and sensitivity of the compounds. The results show that all of the derivatives have high positive HOFs, compound G has the highest theoretical density, and compound F1 has the highest detonation velocity and detonation pressure. Considering both the detonation properties and thermal stabilities, compounds D1 and D4 (3 nitro substituents), E1 - E6 (4 nitro substituents), and G (6 nitro substituents) can be regarded as potential candidates for high-energy density materials.

A regra de Bent contextualiza a força da ligação de hidrogênio em clusters trimoleculares

This article presents a theoretical study of the molecular properties of trimolecular clusters of CnHm∙∙∙HCN∙∙∙HX formed by the ϖ∙∙∙H and n∙∙∙H hydrogen bonds. The interaction strengths of these interactions are in line with the variations in s-character, and independently, the red-shift rise whether stronger or weaker bound systems are carried out. This behavior was justified via NBO analysis and supported by Bent´s rule, wherein the greater variations in s-character of X are in good agreement with larger red-shifts and vice-versa. To conclude, the refinement of the supermolecule approach and NBO binding energies also corroborate in this regard.

Volatile constituents of Aristolochia trilobata L. (Aristolochiaceae): a rich source of sulcatyl acetate

Analysis of the volatile fraction of Aristolochia trilobata stem led to the identification of 6-methyl-5-hepten-2-yl acetate (23.31 ± 0.28%), limonene (15.43 ± 0.030%), linalool (8.70 ± 0.29%), p-cymene (7.81 ± 0.12%), bicyclogermacrene (4.21 ± 0.11%), and spathulenol (4.17 ± 0.14%) as the major constituents of the essential oil. Linalool (29.51 ± 0.49%), 6-methyl-5-hepten-2-ol (19.54 ± 0.82%), 6-methyl-5-hepten-2-yl acetate (8.92 ± 0.16%), and a-terpineol (4.62 ± 0.05%) were identified as major constituents of the hydrolate. The compound 6-methyl-5-hepten-2-yl acetate was isolated for the first time from this plant and was identified as the major component of the volatile fraction.

PYRENE MORPHOLOGY OF THREE SPECIES OF Byrsonima Rich. ex Kunth (Malpighiaceae)1

ABSTRACT The species of the genus Byrsonima Rich. ex Kunth are of great medicinal and economic importance, but they are still poorly studied with respect to their propagules. This study describes, illustrates and comparse morphological aspects of the pyrenes of Byrsonima crassifolia (L.) Kunth, Byrsonima verbascifolia (L.) DC. and Byrsonima coccolobifolia Kunth occurring in areas of savannah of Boa Vista, Roraima. The pyrenes are globoid, obovoid to ovoid, with endocarp dark brown in color, with a corrugated and reticulate surface and corneous consistency. They possess distinctly septate locules with or without seeds, the outer wall of which are dark brown in color with corneous consistency and thin black inner walls also with corneous consistency. The number of locules and seeds per pyrene among the species varies. The seeds are exalbuminous, globoid, obovoid to ovoid, with a thin, smooth integument and are light-brown in color. They have radicular lobes and hypostasis. The embryo is continuous and axial with cylindrical spirally rolled cotyledons. The diameter of pyrenes of Byrsonima crassifolia is greater than in the other two species. The pyrenes of B. coccolobifolia are longer and heavier, while those of B. verbascifolia are lighter and the seeds have greater lengths, widths and thickness compared to the other two species studied. The three species have similar morphologies, differing in the size and weight of pyrenes and seeds.