Extraction and physicochemical characterization of Sargassum vulgare alginate from Brazil

Alginate fractions from Sargassum vulgare brown seaweed were characterized by (1)H NMR and fluorescence spectroscopy and by rheological measurements. The alginate extraction conditions were investigated. In order to carry out the structural and physicochemical characterization, samples extracted for 1 and 5h at 60 degrees C were further purified by re-precipitation with ethanol and denoted as SVLV (S. vulgare low viscosity) and SVHV (S. vulgare high viscosity), respectively. The M/G ratio values for SVLV and SVHV were 1.56 and 1.27, respectively, higher than the ratio for most Sargassum spp. alginates (0.19-0.82). The homopolymeric blocks F(GG) and F(MM) of these fractions characterized by (1)H NMR spectroscopy were 0.43 and 0.55 for SVHV and 0.36 and 0.58 for SVLV samples, respectively, these values typically being within 0.28-0.77 and 0.07-0.41, respectively. Therefore, the alginate samples from S. vulgare are much richer in mannuronic block structures than those from other Sargassum species. Values of M(w) for alginate samples were also calculated using intrinsic viscosity data. The M(w) value for SVLV (1.94 x 10(5)g/mol) was lower than that for SVHV (3.3 x 10(5)g/mol). Newtonian behavior was observed for a solution concentration as high as 0.7% for SVLV, while for SVHV the solutions behaved as a Newtonian fluid up to 0.5%. The optimal conditions for obtaining the alginates from S. vulgare were 60 degrees C and 5h extraction. Under these conditions, a more viscous alginate in higher yield was extracted from the seaweed biomass.     

Influence of Socioeconomic Factors on the Knowledge and Consumption of Firewood in the Atlantic Forest of Northeast Brazil

Economic Botany - We aim to evaluate whether socioeconomic factors influence the knowledge, use, preference, and consumption of firewood in a rural community in Northeast Brazil. We conducted...     

Genetic Diversity of the Cryptococcus gattii Species Complex in Mato Grosso State,Brazil

Mycopathologia - Cryptococcosis is caused by fungi of the genus Cryptococcus. Owing to its importance, this study aimed to analyze the genetic diversity of C. gattii isolates from animals, humans,...     

Synthesis and larvicidal activity of indole derivatives against Aedes aegypti (Diptera: Culicidae)

In light of the challenges to control Aedes aegypti and the critical role that it plays as arbovirus vector, it is imperative to adopt strategies that provide fast, efficient and environmentally safe control of the insect population. In the present study, we synthesized six indole derivatives (C1‐C6) and examined their larvicidal activity and persistence against Ae. aegypti larvae, as well as their toxicity towards Raw 264.7 macrophages, Vero cells, Chlorella vulgaris BR017, Scenedesmus obliquus BR003, Caenorhabditis elegans N2 and Galleria mellonella. Among the bioactive compounds (C1, C2, C4 and C5), C2 exerted the strongest larvicidal activity against Ae. aegypti, with LC50 = 1.5 μg/ml (5.88 µM) and LC90 = 2.4 μg/ml (9.50 µM), indicating that the presence of chlorine or bromine groups in the aromatic ring improved the larvicidal activity of the indole derivatives. C1, C2, C4 and C5 did not reduce viability of RAW 264.7 macrophages, Vero cells, C. elegans N2 and G. mellonella. Compounds C1, C2 and C5 did not affect the growth of C. vulgaris BR017 and S. obliquus BR003. Analysis of larvicidal persistence under laboratory conditions revealed that the effect of compounds C1, C2, C4 and C5 lasted for 30 days and caused 100% of larvae mortality within few hours. Altogether, our findings demonstrate that the indole derivatives C1, C2, C4 and C5 effectively control Ae. aegypti larvae population, without clear signs of toxicity to mammalian cells, algae, C. elegans and G. mellonella.     

Personalized pathology test for Cardio-vascular disease: Approximate Bayesian computation with discriminative summary statistics learning

Cardio/cerebrovascular diseases (CVD) have become one of the major health issue in our societies. But recent studies show that the present pathology tests to detect CVD are ineffectual as they do not consider different stages of platelet activation or the molecular dynamics involved in platelet interactions and are incapable to consider inter-individual variability. Here we propose a stochastic platelet deposition model and an inferential scheme to estimate the biologically meaningful model parameters using approximate Bayesian computation with a summary statistic that maximally discriminates between different types of patients. Inferred parameters from data collected on healthy volunteers and different patient types help us to identify specific biological parameters and hence biological reasoning behind the dysfunction for each type of patients. This work opens up an unprecedented opportunity of personalized pathology test for CVD detection and medical treatment.     

Genetic information improves the prediction of major adverse cardiovascular events in the GENEMACOR population

The inclusion of a genetic risk score (GRS) can modify the risk prediction of coronary artery disease (CAD), providing an advantage over the use of traditional models. The predictive value of the genetic information on the recurrence of major adverse cardiovascular events (MACE) remains controversial. A total of 33 genetic variants previously associated with CAD were genotyped in 1587 CAD patients from the GENEMACOR study. Of these, 18 variants presented an hazard ratio >1, so they were selected to construct a weighted GRS (wGRS). MACE discrimination and reclassification were evaluated by C-Statistic, Net Reclassification Index and Integrated Discrimination Improvement methodologies. After the addition of wGRS to traditional predictors, the C-index increased from 0.566 to 0.572 (p=0.0003). Subsequently, adding wGRS to traditional plus clinical risk factors, this model slightly improved from 0.620 to 0.622 but with statistical significance (p=0.004). NRI showed that 17.9% of the cohort was better reclassified when the primary model was associated with wGRS. The Kaplan-Meier estimator showed that, at 15-year follow-up, the group with a higher number of risk alleles had a significantly higher MACE occurrence (p=0.011). In CAD patients, wGRS improved MACE risk prediction, discrimination and reclassification over the conventional factors, providing better cost-effective therapeutic strategies.     

Fine structure of the branchial epithelium in the teleost Oreochromis niloticus

We have studied the gill epithelium of Oreochromis niloticus using transmission electron microscopy with the particular interested relationship between cell morphology and osmotic, immunoregulatory, or other non‐regulatory functions of the gill. Pavement cells covered the filament epithelium and lamellae of gills, with filament pavement cells showing distinct features from lamellar pavement cells. The superficial layer of the filament epithelium was formed by osmoregulatory elements, the columnar mitochondria‐rich, mucous and support cells, as well as by their precursors. Light mitochondria‐rich cells were located next to lamellae. They exhibited an apical crypt with microvilli and horizontal small dense rod‐like vesicles, sealed by tight junctions to pavement cells. Dark mitochondria‐rich cells had long dense rod‐like vesicles and a small apical opening sealed by tight junctions to pavement cells. The deep layer of the filament epithelium was formed by a network of undifferentiated cells, containing neuroepithelial and myoepithelial cells, macrophage and eosinophil‐like cells and their precursors, as well as precursors of mucous cells. The lateral‐basal surface was coated by myoepithelial cells and a basal lamina. The lamellar blood lacunae was lined by pillar cells and surrounded by a basal lamina and pericytes. The data presented here support the existence of two distinct types of pavement cells, mitochondria‐rich cells, and mitochondria‐rich cells precursors, a structural role for support cells, a common origin for pavement cells and support cells, a paracrine function for neuroepithelial cells in the superficial layer, and the control of the lamellar capillary base by endocrine and contractile cells. Data further suggest that the filament superficial layer is involved in gill osmoregulation, that may interact, through pale mitochondria‐rich cells, with the deep layer and lamellae, whereas the deep layer, through immune and neuroendocrine systems, acts in the regeneration and defense of the tissue. J. Morphol. 2010. © 2010 Wiley‐Liss, Inc.     

Oral exfoliative cytology in the diagnosis of paracoccidioidomycosis

OBJECTIVE: To assess the efficacy of conventional oral exfoliative cytology as a diagnostic tool in paracoccidioidomycosis. STUDY DESIGN: Cytologic smears and incisional biopsies were obtained from 10 patients with a clinical suspicion and oral manifestations of paracoccidioidomycosis. Cytologic smears and sections of the incisional biopsy underwent methenamine silver staining for fungi according to the Gomori-Grocott method. The dry glass slides were examined at 400 or 1,000 x magnification, and the presence and shape of yeasts of Paracoccidioides brasiliensis were investigated. RESULTS: Yeasts of the fungus P brasiliensis were clearly identified in cytologic smears and sections from incisional biopsies in all cases analyzed (100.0%). CONCLUSION: Cytology of oral samples proved an effective diagnostic method for the detection of paracoccidioidomycosis in humans.     

Characterisation of the last Fe-S cluster-binding subunit of Neurospora crassa complex I

We have cloned cDNAs encoding the last iron-sulphur protein of complex I from Neurospora crassa. The cDNA sequence contains an open reading frame that codes for a precursor polypeptide of 226 amino acid residues with a molecular mass of 24972 Da. Our results indicate that the mature protein belongs probably to the peripheral arm of complex I and is rather unstable when not assembled into the enzyme. The protein is highly homologous to the PSST subunit of bovine complex I, the most likely candidate to bind iron-sulphur cluster N-2. All the amino acid residues proposed to bind such a cluster are conserved in the fungal protein.