Effects <Emphasis Type="Italic">per se</Emphasis> of Organic Solvents in the Cerebral Acetylcholinesterase of Rats

Acetylcholinesterase (AChE) was studied in different rat brain regions (cerebellum, hypothalamus, striatum, hippocampus and cortex) in the presence of different organic solvents normally used in the in vitro assay. The organic solvents used were acetone (C₃H₆O), acetonitrile (C₂H₃N), ethyl alcohol (C₂H₆O), isopropyl alcohol (C₃H₈O), methyl alcohol (CH₄O), tert-butyl alcohol (C₄H₁₀O) and dimethyl sulfoxide (DMSO, C₂H₆OS) ranging from 0.6 to 10%. Ethyl and methyl alcohol presented no effect on AChE activity at any of the concentrations and brain structures tested. In the hippocampus, isopropyl alcohol did not demonstrate a significant inhibitory effect, even at high concentrations. Tert-butyl alcohol presented an interesting result, increased AChE activity (P < .05) in the hypothalamus (1.8%), cortex (1.8 and 2.5) and striatum (1.2, 1.8 and 2.5%) and decreased activity at a concentration of 10% in the cortex (P < .05) and striatum (P < .01). Acetone and acetonitrile presented similar results, both significantly inhibiting AChE in all structures (5%, P < .05 and 10%, P < .01). DMSO exhibited a highly inhibitory effect at practically all concentrations tested (P < .01). In conclusion, for testing new compounds on AChE activity in vitro, methyl and ethyl alcohol may be the best organic solvent choice.     

Ascorbic acid and flavonoid-peroxidase reaction as a detoxifying system of H(2)O(2) in grapevine leaves

Biosynthesis of both ascorbic acid (AsA) and peroxidase activity were induced by light in cv. Sultana grapevine leaves. Induced peroxidase activity mainly involved basic isoenzymes of pI 9.8 and 9.6 and catalyzed the oxidation of flavonoids like quercetin and kaempferol and derivatives of hydroxycinnamic acids such as ferulic and p-coumaric acids, but not AsA. However, the peroxidase-dependent oxidation of ferulic acid and quercetin was temporarily suppressed by AsA as long as it remained in the reaction medium. Kinetics and spectroscopic results indicated that AsA was oxidized to dehydroascorbic acid only in the presence of phenols or flavonoids, and did not interfere with the catalytic activity of the peroxidase. Ascorbate peroxidase isoenzymes (APx), whose activities are widely considered central for detoxification of H(2)O(2) in most plant cells, were not detected in grape leaves extracts. The significance of light stimulus on peroxidase activity and leaf AsA content is discussed in terms of a flavonoid-redox cycle proposed as an alternative system to detoxify H(2)O(2) in grapevine leaves.     

Continuous gametogenesis in the neotropical freshwater teleost, Bryconops affinis (Pisces:Characidae)

The gametogenesis of Bryconops affinis was studied by light, transmission and scanning electron microscopy. The spermatogenesis is semi-cystic and spermatids are released into the lumen of seminiferous tubules, where spermiogenesis is completed. Spermatozoa have an ovoid head, a rudimentary middle piece with a small number of mitochondria and long flagellum (primitive spermatozoa). The Sertoli and Leydig cells show secretory activity during spermatogenesis. By the end of this phenomenon, the Sertoli cells phagocytize the residual spermatozoa, while the Leydig cells show involuted characteristics. With regard to the oogenesis process, the oocyte development was divided into four stages based on the cytological characteristics of the oocyte and its surrounding layers. Ultrastructural analysis revealed that the zona pellucida is formed during the previtellogenic stage. Specializations associated to the outer layer of the zona pellucida may be related to the egg's adherence to the substrata.     

Mesenchymal stem cell cultivation in electrospun scaffolds: mechanistic modeling for tissue engineering

Tissue engineering is a multidisciplinary field of research in which the cells, biomaterials, and processes can be optimized to develop a tissue substitute. Three-dimensional (3D) architectural features from electrospun scaffolds, such as porosity, tortuosity, fiber diameter, pore size, and interconnectivity have a great impact on cell behavior. Regarding tissue development in vitro, culture conditions such as pH, osmolality, temperature, nutrient, and metabolite concentrations dictate cell viability inside the constructs. The effect of different electrospun scaffold properties, bioreactor designs, mesenchymal stem cell culture parameters, and seeding techniques on cell behavior can be studied individually or combined with phenomenological modeling techniques. This work reviews the main culture and scaffold factors that affect tissue development in vitro regarding the culture of cells inside 3D matrices. The mathematical modeling of the relationship between these factors and cell behavior inside 3D constructs has also been critically reviewed, focusing on mesenchymal stem cell culture in electrospun scaffolds.     

Rivers shape population genetic structure in Mauritia flexuosa (Arecaceae)

The Mauritia flexuosa L.f. palm is known as the “tree of life” given its importance as fundamental food and construction resources for humans. The species is broadly distributed in wet habitats of Amazonia and dry habitats of the Amazon and Orinoco river basins and in the Cerrado savanna. We collected 179 individuals from eight different localities throughout these habitats and used microsatellites to characterize their population structure and patterns of gene flow. Overall, we found high genetic variation, except in one savanna locality. Gene flow between populations is largely congruent with river basins and the direction of water flow within and among them, suggesting their importance for seed dispersal. Further, rivers have had a higher frequency of human settlements than forested sites, contributing to population diversity and structure through increased human use and consumption of M. flexuosa along rivers. Gene flow patterns revealed that migrants are sourced primarily from within the same river basin, such as those from Madeira and Tapajós basins. Our work suggests that rivers and their inhabitants are a critical element of the landscape in Amazonia and have impacted the dispersal and subsequent distribution of tropical palm species, as shown by the patterns of genetic variation in M. flexuosa.     

SWITCH in Belo Horizonte,Brazil: infiltration and detention systems for more sustainable stormwater control in Belo Horizonte

Belo Horizonte, Brazil, is one of the demonstration cities of the SWITCH project. Flooding and wet weather pollution are major issues for the city. Because of this SWITCH in Belo Horizonte has focussed on more sustainable urban drainage systems (SUDS). Demonstrations are being conducted of infiltration and detention devices, artificial wetlands, and rainfall harvesting. This paper focuses on the use of detention and infiltration trenches to control runoff and abate wet weather pollution. Preliminary results indicate that use of these devices have potential for significantly mitigating suspended matter such as heavy metals originating from road surfaces.     

Morphological and quantitative evaluation of the ovarian recrudescence in Nile tilapia (Oreochromis niloticus) after spawning in captivity

The Nile tilapia is one of the most important fish species for aquaculture worldwide. Understanding their reproductive biology is essential for improving their aquaculture methods. The morphological and quantitative dynamics of ovarian recrudescence of Oreochromis niloticus was studied for 21 days postspawning. To accomplish this, breeding females were kept in controlled conditions and ovarian samples were collected weekly for histological, ultrastructural and morphometric analyses. Ovarian follicle morphology revealed an intense synthesis activity of the follicular cells, which actively contributed to formation of the zona radiata and oocyte development following spawning. Recently spawned ovaries contained follicles at all developmental stages, but they were predominantly early primary growth (～42%) and full‐grown follicles (～20%). Remnants of spawning, postovulatory follicle complexes represented approximately 5% of the former ovarian follicles immediately after spawning, and less than 1% after 7 days. Atretic follicles accounted for approximately 2% of the follicles studied during the period. The stock of primary growth follicles was stable during ovarian recrudescence, indicating their availability for continuous recruitment. Only the frequency of full‐grown follicles significantly increased in the ovaries during recrudescence, representing approximately 35% of the follicles 21 days postspawning. The diameters of all follicles were significantly different between the periods analyzed. The ovaries' morphological characteristics, the maintenance of young follicles stocks and the gradual and significant increase in the proportion and diameter of full‐grown follicles showed a rapid ovarian recovery and follicular growth of O. niloticus, in 21 days at 29.5°C, necessary for the next spawning. J. Morphol. 275:348–356, 2014. © 2013 Wiley Periodicals, Inc.     

Oseltamivir-resistant influenza A(H1N1)pdm09 virus in southern Brazil

The neuraminidase (NA) genes of A(H1N1)pdm09 influenza virus isolates from 306 infected patients were analysed. The circulation of oseltamivir-resistant viruses in Brazil has not been reported previously. Clinical samples were collected in the state of Rio Grande do Sul (RS) from 2009-2011 and two NA inhibitor-resistant mutants were identified, one in 2009 (H275Y) and the other in 2011 (S247N). This study revealed a low prevalence of resistant viruses (0.8%) with no spread of the resistant mutants throughout RS.