19 resultados para Suspension-cultures
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo
Resumo:
The effects of aluminum (Al) on the activities of antioxidant enzymes and ferritin expression were studied in cell suspension cultures of two varieties of Coffea arabica, Mundo Novo and Icatu, in medium with pH at 5.8. The cells were incubated with 300 µM Al3+, and the Al speciation as Al3+ was 1.45% of the mole fraction. The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) were increased in Mundo Novo, whereas glutathione reductase (GR) and guaiacol peroxidase (GPOX) activities remained unchanged. SOD, GR, and GST activities were increased in Icatu, while CAT activity was not changed, and GPOX activity decreased. The expression of two ferritin genes (CaFer1 and CaFer2) were analyzed by Real-Time PCR. Al caused a downregulation of CaFER1 expression and no changes of CaFER2 expression in both varieties. The Western blot showed no alteration in ferritin protein levels in Mundo Novo and a decrease in Icatu. The differential enzymes responses indicate that the response to Al is variety-dependent.
Resumo:
Sewage sludge has been used to fertilize coffee, increasing the risk of metal contamination in this crop. The aim of this work was to study the effects of Cd, Zn and Ni in adult coffee plants growing under field conditions. Seven-year-old coffee plants growing in the field received one of three;loses of Cd, Zn or Ni: 15,45 and 90 g Cd plant(-1); 35, 105 and 210 g Ni plant(-1); and 100, 300 and 600 g Zn plant(-1), with all three metals in the form of sulphate salts. After three months, we noticed good penetration of the three metals into the soil, especially in the first 50 cm, which is the region where most coffee plant roots are concentrated. Leaf concentrations of K, Ca, Mg, S, B, Cu, Fe and Mn were nor affected. N levels did not change with the application of Ni or Zn but were reduced with either 45 or 90 g Cd plant(-1). Foliar P concentrations decreased with the addition of 45 and 90 g Cd plant(-1) and 600 g Zn plant(-1). Zn levels in leaves were not affected by the application of Cd or Ni. The highest concentrations. of Zn were found in branches (30-230 mg kg(-1)), leaves (7-35 mg kg(-1)) and beam (4-6.5 mg kg(-1)); Ni was found in leaves (4-45 mg kg(-1)), branches (3-18 mg kg(-1)) and beans (1-5 mg kg(-1)); and Cd was found in branches (0-6.2 mg kg(-1)) and beans (0-1.5 mg kg(-1)) but was absent in leaves. The mean yield of two harvests was not affected by Ni, but it decreased at the highest dose of Zn (600 g plant(-1)) and the two higher doses of Cd (45 and 90 g plant(-1)). Plants died when treated with the highest dose of Cd and showed symptoms of toxicity with the highest dose of Zn. Nevertheless, based on the amounts of metal used and the results obtained, we conclude that coffee plants are highly tolerant to the three metals tested. Moreover, even at high doses, there was very little transport to the beans, which is the part consumed by humans. (C) 2011 Elsevier B.V. All rights reserved.
Resumo:
In this work, it was observed a straight relationship between the manipulation of the reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio, nitric oxide emission and quality and number of early somatic embryos in Araucaria angustifolia, a Brazilian endangered native conifer. In low concentrations GSH (0.01 and 0.1 mM) is a potential NO scavenger in the culture medium. Furthermore, it can increase the number of early SE formed in cell suspension culture media in a few days. However, the maintenance in this low redox state lead to a loss of early somatic embryos polarization. In gelled culture medium, high levels of GSH (5 mM) allows the development of globular embryos presenting a high NO emission on embryo apex, stressing its importance in the differentiation and cell division. Taken together these results indicate that the modification of the embryogenic cultures redox state might be an effective strategy to develop more efficient embryogenic systems in A. angustifolia. (c) 2012 Elsevier Ireland Ltd. All rights reserved.
Resumo:
Plant secondary metabolites are a group of naturally occurring compound classes biosynthesized by differing biochemical pathways whose plant content and regulation is strongly susceptible to environmental influences and to potential herbal predators. Such abiotic and biotic factors might be specifically induced by means of various mechanisms, which create variation in the accumulation or biogenesis of secondary metabolites. Hence the dynamic aspect of bioactive compound synthesis and accumulation enables plants to communicate and react in order to overcome imminent threats. This contribution aims to review the most important mechanisms of various abiotic and biotic interactions, such as pathogenic microorganisms and herbivory, by which plants respond to exogenous influences, and will also report on time-scale variable influences on secondary metabolite profiles. Transmission of signals in plants commonly occurs by 'semiochemicals', which are comprised of terpenes, phenylpropanoids, benzenoids and other volatile compounds. Due to the important functions of volatile terpenes in communication processes of living organisms, as well as its emission susceptibility relative to exogenous influences, we also present different scenarios of concentration and emission variations. Toxic effects of plants vary depending on the level and type of secondary metabolites. In farming and cattle raising scenarios, the toxicity of plant secondary metabolites and respective concentration shifts may have severe consequences on livestock production and health, culminating in adverse effects on crop yields and/or their human consumers, or have an adverse economic impact. From a wider perspective, herbal medicines, agrochemicals or other natural products are also associated with variability in plant metabolite levels, which can impact the safety and reliable efficacy of these products. We also present typical examples of toxic plants which influence livestock production using Brazilian examples of toxicity of sapogenins and alkaloids on livestock to highlight the problem. (c) 2012 Elsevier B.V. All rights reserved.
Resumo:
Abstract Background Hemophilia A is a bleeding disorder caused by deficiency in coagulation factor VIII. Recombinant factor VIII (rFVIII) is an alternative to plasma-derived FVIII for the treatment of hemophilia A. However, commercial manufacturing of rFVIII products is inefficient and costly and is associated to high prices and product shortage, even in economically privileged countries. This situation may be solved by adopting more efficient production methods. Here, we evaluated the potential of transient transfection in producing rFVIII in serum-free suspension HEK 293 cell cultures and investigated the effects of different DNA concentration (0.4, 0.6 and 0.8 μg/106 cells) and repeated transfections done at 34° and 37°C. Results We observed a decrease in cell growth when high DNA concentrations were used, but no significant differences in transfection efficiency and in the biological activity of the rFVIII were noticed. The best condition for rFVIII production was obtained with repeated transfections at 34°C using 0.4 μg DNA/106 cells through which almost 50 IU of active rFVIII was produced six days post-transfection. Conclusion Serum-free suspension transient transfection is thus a viable option for high-yield-rFVIII production. Work is in progress to further optimize the process and validate its scalability.
Resumo:
In this joint article we test the common assumption that a measure of culture developed for the national level can also be used for comparing regions within a country. Three different research projects independently measured culture differences within the Federal Republic of Brazil, all three using a version of Hofstede`s Values Survey Module (VSM). The largest provided separate scores for all of Brazil`s 27 states, the next largest for 17 of the more populous states. Factor analyses of VSM item scores across states in both cases only very partly replicated Hofstede`s cross-national dimension structure; only Individualism versus Collectivism reappeared clearly. We attribute this lack of fit to a restriction of range of VSM item scores among states within a common Brazilian national culture. The item scores did show a cultural clustering of states that fairly closely followed the administrative division of the country into five regions. The culture profiles for these regions show remarkable differences between the Northeast with its Afro-Brazilian roots and the North with its native Indian roots. On the issue of comparing regional cultures, we found the VSM, based on global differences, too coarse a net for catching the finer cultural nuances between Brazilian states. Adding locally defined items would have made the studies more meaningful to Brazilians.
Resumo:
Wet impregnation of pre-synthesized surfactant-stabilized aqueous rhodium (0) colloidal suspension on silica was employed in order to prepare supported Rh-0 nanoparticles of well-defined composition, morphology and size. A magnetic core-shell support of silica (Fe(3)O4@SiO2) was used to increase the handling properties of the obtained nanoheterogeneous catalyst. The nanocomposite catalyst Fe3O4@SiO2-Rh-0 NPs was highly active in the solventless hydrogenation of model olefins and aromatic substrates under mild conditions with turnover frequencies up to 143,000 h(-1). The catalyst was characterized by various transmission electron microscopy techniques showing well-dispersed rhodium nanoparticles (similar to 3 nm) mainly located at the periphery of the silica coating. The heterogeneous magnetite-supported nanocatalyst was investigated in the hydrogenation of cyclohexene and compared to the previous surfactant-stabilized aqueous Rh-0 colloidal suspension and various silica-supported Rh-0 nanoparticles. Finally, the composite catalyst could be reused in several runs after magnetic separation. (C) 2011 Elsevier B. V. All rights reserved.
Resumo:
Biofilms represent a great concern for food industry, since they can be a source of persistent contamination leading to food spoilage and to the transmission of diseases. To avoid the adhesion of bacteria and the formation of biofilms, an alternative is the pre-conditioning of surfaces using biosurfactants, microbial compounds that can modify the physicochemical properties of surfaces changing bacterial interactions and consequently adhesion. Different concentrations of the biosurfactants, surfactin from Bacillus subtilis and rhamnolipids from Pseudomonas aeruginosa, were evaluated to reduce the adhesion and to disrupt biofilms of food-borne pathogenic bacteria. Individual cultures and mixed cultures of Staphylococcus aureus, Listeria monocytogenes and Salmonella Enteritidis were studied using polystyrene as the model surface. The pre-conditioning with surfactin 0.25% reduced by 42.0% the adhesion of L monocytogenes and S. Enteritidis, whereas the treatment using rhamnolipids 1.0% reduced by 57.8% adhesion of L monocytogenes and by 67.8% adhesion of S. aureus to polystyrene.Biosurfactants were less effective to avoid adhesion of mixed cultures of the bacteria when compared with individual cultures. After 2 h contact with surfactin at 0.1% concentration, the pre-formed biofilms of S. aureus were reduced by 63.7%, L. monocytogenesby 95.9%, S. Enteritidis by 35.5% and the mixed culture biofilm by 58.5%. The rhamnolipids at 0.25% concentration removed 58.5% the biofilm of S. aureus, 26.5% of L monocytogenes, 23.0% of S. Enteritidis and 24.0% the mixed culture after 2 h contact. In general, the increase in concentration of biosurfactants and in the time of contact decreased biofilm removal percentage. These results suggest that surfactin and rhamnolipids can be explored to control the attachment and to disrupt biofilms of individual and mixed cultures of the food-borne pathogens. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
Goat breeding in Sardinia constitutes an important source of income for farming and shepherding activities. In this study 170 LAB strains were isolated from Sardinian goat's milk and tested for bacteriocins production against several food-borne pathogenic microorganisms. Four isolates (SD1, SD2, SD3 and SD4) were selected for their effective inhibition on Listeria monocytogenes. The strains were classified as members of Enterococcus genus, according to their biochemical and physiological characteristics, and then genetically identified as Enterococcus faecium. In MRS broth at 37 degrees C, bacteriocins SD1 and SD2 were produced at much higher levels (51200 AU/ml) compared to bacteriocin SD3 (3200 AU/ml) and bacteriocin SD4 (800 AU/ml). Their peptides were inactivated by proteolytic enzymes, but not when treated with alpha-amylase, catalase and lipase. The four bacteriocins remained stable at pH from 2.0 to 12.0, after exposure to 100 degrees C for 120 min and were not affected by the presence of surfactants and salts (N-Laourylsarcosine, NaCl, SDS, Triton X-100, Tween 20, Tween 80 and urea). Their molecular size was determined to be approximately 5 kDa by tricine-SDS-PAGE. Since the strains exhibited a strong antimicrobial activity against 21 L monocytogenes strains and 6 Salmonella spp. isolates, they should be considered as potential bio-preservatives cultures for fermented food productions. Moreover, due to their technological features, the four strains could be taken in account for using as adjunct NSLAB (non-starter lactic acid bacteria) rather than as starter culture. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
This work evaluates the spatial distribution of normalised rates of droplet breakage and droplet coalescence in liquidliquid dispersions maintained in agitated tanks at operation conditions normally used to perform suspension polymerisation reactions. Particularly, simulations are performed with multiphase computational fluid dynamics (CFD) models to represent the flow field in liquidliquid styrene suspension polymerisation reactors for the first time. CFD tools are used first to compute the spatial distribution of the turbulent energy dissipation rates (e) inside the reaction vessel; afterwards, normalised rates of droplet breakage and particle coalescence are computed as functions of e. Surprisingly, multiphase simulations showed that the rates of energy dissipation can be very high near the free vortex surfaces, which has been completely neglected in previous works. The obtained results indicate the existence of extremely large energy dissipation gradients inside the vessel, so that particle breakage occurs primarily in very small regions that surround the impeller and the free vortex surface, while particle coalescence takes place in the liquid bulk. As a consequence, particle breakage should be regarded as an independent source term or a boundary phenomenon. Based on the obtained results, it can be very difficult to justify the use of isotropic assumptions to formulate particle population balances in similar systems, even when multiple compartment models are used to describe the fluid dynamic behaviour of the agitated vessel. (C) 2011 Canadian Society for Chemical Engineering
Resumo:
FALCAI MJ, LOUZADA MJQ, DE PAULA FJA, OKUBO R, VOLPON JB. A modified technique of rat tail suspension for longer periods of observation. Aviat Space Environ Med 2012; 83:1176-80. Background: Rat tail suspension is an accepted method to create experimental osteopenia. However, suspension periods longer than 3 wk may cause tail skin sloughing or rat slippage. The hypothesis was that a traction system with skeletal anchorage through one tail vertebra would prolong the suspension time without significant complications. Methods: There were 80 young adult female Wistar rats that were submitted to one of the following interventions: skeletal tail suspension (N = 20), skin tail suspension (N = 20), no intervention (N = 20), and a baseline control (N = 20). All animals were followed up either for 3 (N = 10) or 6 (N = 10) wk. Animals were assessed for clinical signs of stress and tolerance to suspension. The femur evaluation was in terms of mineral density content, mechanical resistance, and histomorphometry. Results/Discussion: All animals reached the 3-wk end point. However, for the 6-wk period, seven animals suspended by the skin traction method were discarded (70%) because of signs of stress and skin sloughing. In contrast, there was one loss in the skeletal suspension group (10%). All suspended animals developed similar osteopenia at 3 wk characterized by decreased bone mineral content, weakened bone resistance, and loss of femoral mass. At 6 wk, all suspended animals had similar osteopenic parameters, but they were not statistically different from those of the rats in the 3-wk groups. Therefore, suspension longer than 3 wk did not increase the bone deterioration in the femur.
Resumo:
Leaf extract of Centella asiatica has been used as an alternative medicine for memory improvement in the Indian Ayurvedic system of medicine for a long time. Although several studies have revealed its effect in ameliorating the cognitive impairment in rat models of Alzheimer's disease, the molecular mechanism of C. asiatica on neuroprotection still remains unexplained. In this study, we investigated the effects of C. asiatica water extract on activity of subtypes of phospholipase A(2) (PLA(2)) in primary cultures of rat cortical neurons and quantified by HPLC a possible molecule responsible for the activity. The cPLA(2) and sPLA(2) activities were inhibited in vitro by asiaticoside present in the water extract of C. asiatica. This extract may be a candidate for the treatment of neurodegenerative processes because of its pharmacological activity in the brain and its low toxicity, as attested by its long popular use as a natural product.
Resumo:
This study focuses on comparison of perceptions of ethical business cultures in large business organizations from four largest emerging economies, commonly referred to as the BRICs (Brazil, Russia, India, and China), and from the US. The data were collected from more than 13,000 managers and employees of business organizations in five countries. The study found significant differences among BRIC countries, with respondents from India and Brazil providing more favorable assessments of ethical cultures of their organizations than respondents from China and Russia. Overall, highest mean scores were provided by respondents from India, the US, and Brazil. There were significant similarities in ratings between the US and Brazil.
Resumo:
Context: Sapindus saponaria L. (Sapindaceae) bark, root, and fruits are used as sedatives and to treat gastric ulcer and also demonstrate diuretic and expectorant effects. Objective: The anti-snake venom properties of callus of S. saponaria are investigated here for the first time. Materials and methods: In vitro cultivated callus of Sapindus saponaria were lyophilized, and the extracts were prepared with different solvents, before submitting to phytochemical studies and evaluation of the anti-ophidian activity. Crude extracts were fractionated by liquid-liquid partition and the fractions were monitored by thin layer chromatography (TLC). Subsequently, anti-ophidian activities were analyzed toward Bothrops jararacussu Lacerda (Viperidae), B. moojeni Hoge (Viperidae), B. alternates Dumeril (Viperidea) and Crotalus durissus terrificus Lineu (Viperidae) venoms and isolated myotoxins and phospholipase A(2) (PLA(2)). Results: Fractions A1, A2 and the extract in MeOH:H2O (9:1) significantly inhibited the toxic and pharmacological activities induced by snake venoms and toxins, when compared to other extracts and fractions. The lethal, clotting, phospholipase, edema-inducing, hemorrhagic and myotoxic activities were partially inhibited by the different extracts and fractions. TLC profiles of the crude extracts (B and C) and fractions (A1 and A2) showed beta-sitosterol and stigmasterol as their main compounds. Stigmasterol exhibited inhibitory effects on enzymatic and myotoxic activities of PLA(2). Discussion and conclusion: Sapindus saponaria extracts and fractions presented anti-ophidian activity and could be used as an adjuvant to serum therapy or for its supplementation, and in addition, as a rich source of potential inhibitors of enzymes involved in several pathophysiological human and animal diseases.
Resumo:
The objective was to evaluate the performance of surveillance cultures at various body sites for Staphylococcus aureus colonization in pregnant women and newborns (NB) and the factors associated with nasal colonization. For NB, 4 sites were evaluated: nares, oropharynx, perineum, and umbilical stump (birth, third day, and weekly). For pregnant women, 4 sites during labor: anterior nares, anus, perineum, and oropharynx. Nasally colonized patients were compared with colonized only extranasally. Colonization was 53% of 392 pregnant women (methicillin-resistant S. aureus [MRSA]: 4%) and 47% of 382 NB (MRSA: 9%). For newborn patients, the best body site was the umbilical stump (methicillin-susceptible S. aureus [MSSA]: 64%; MRSA: 68%) and the combination of nares + umbilical (MSSA: 86%; MRSA: 91%). Among pregnant women, the best body site was the anterior nares (MSSA: 59%; MRSA: 67%) and the combination of nares + oropharynx (MSSA: 83%; MRSA: 80%). A smaller number of household members were associated with MRSA carriage in pregnant women (2.2 +/- 0.6 versus 3.6 +/- 1.8; P = 0.04). In conclusion, multiple culture sites are needed. Control programs based on surveillance cultures may be compromised. (C) 2012 Elsevier Inc. All rights reserved.