Ultrastructural studies of the mandibular glands of the minima, media and soldier ants of Atta sexdens rubropilosa (Forel 1908)

The mandibular glands of Hymenoptera are structures associated with the mandibles and constitute part of the salivary glands system. Histological studies in workers of Atta sexdens rubropilosa revealed that this gland contains two portions: a secretory and a storage portion or reservoir. Both portions are connected by means of canaliculi. The object of the present work was the study of the ultratructure of the mandibular glands of minima, media and soldier ant of A. s. rubropilosa by TEM techniques. The glands, in the three castes studied, possess a reservoir, constituted by a simple pavementous epithelium surrounded by the cuticular intima and the secretory portion is constituted by cells of rounded shape. The secretory cells, mainly of minima and soldier, were rich in smooth endoplasmic reticulum. The media worker and soldier presented a large number of mitochondria, of varying shape. Well-developed Golgi complexes were also present in the soldiers. The secretory cells in minima, media and soldier were provided with collecting intracellular canaliculi, which were linked to the reservoir through the extracellular portion. The cytoplasm of the canaliculi-forming cell was poor in organelles. In the individuals of the three castes of A. s. rubropilosa, the presence of lipid secretion granules suggested, beyond the other functions, also a possible pheromonal action. The different roles executed by the different insect castes are directly dependent on the glandular products and, consequently, on the secretory cellular characteristics. (c) 2005 Elsevier Ltd. All rights reserved.

Comparison of microbial numbers in soils by using various culture media and temperatures

The influence of different media and incubation temperatures on the quantification of microbial populations in sorghum, eucalyptus and forest soils was evaluated. Microbial growth was compared by using complex (tryptone soybean agar, TSA, casein-starch, CS, and Martin) and saline (Thorton, M3, Czapeck) media and incubation temperatures of 25 and 30° C. Higher numbers of total bacterial. and fungal colony-forming units (CFU) were observed in sorghum soils, and of spore-forming and Gram-negative bacteria in forest soils than other soils. Actinomycetes counts were highest in forest soil when using CS medium at 30° C and in sorghum soil at 25° C in M3 medium. Microorganism counts were dependent on the media and incubation temperatures. The counts at temperatures of 30° C were significantly higher than at 25° C. Microbial quantification was best when using TSA medium for total. and spore-forming bacteria, Thorton for Gram-negative bacteria, M3 for actinomycetes, and Martin for fungi. © 2005 Elsevier GmbH. All rights reserved.

Development of a bioassay to quantify the ricin toxin content of castor bean (Ricinus communis L.) seeds

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The effect of gastric dilatation in rats submitted to gasified water ingestion under the hepatic metabolic function

INTRODUÇÃO: O excesso de peso na população aumentou de forma significante nas últimas décadas e as bebidas gasosas tornaram-se um fator ambiental importante no comportamento alimentar das pessoas, sendo os EUA, México e Brasil, nesta ordem, os três maiores paises produtores e consumidores de refrigerantes. OBJETIVO: Investigar os efeitos da dilatação gástrica em ratos submetidos a ingestão de água gaseificada, veículo uniforme para todos os refrigerantes, sobre parâmetros metabólicos da função hepática. MÉTODOS: Foram constituídos dois grupos de 15 ratos acompanhados por 15 semanas. Ao Grupo-I, foram oferecidos 200 g/dia de ração ad libitum e 100 ml de água não gaseificada em 3 períodos diários, ao Grupo-II, foram oferecidos 200 g/dia de ração ad libitum e 100 ml de água gaseificada em 3 períodos diários; em cada grupo,foram calculados a média (x) e o desvio padrão (s); para todos os atributos estudados foi utilizado o método estatístico de teste t pareado, comparando-se GI com GII, testando-se o efeito dos tipos de água. RESULTADOS: Os resultados identificaram que os animais que foram submetidos ao tratamento com água gaseificada (Grupo-II), apresentaram um aumento de transaminase glutâmica pirúvica (TGP) e fosfatase alcalina p<0,01), tendência de aumento da transaminase glutâmica oxalacética (TGO) (0,10>p>0,05) e aumento da área gástrica com alterações morfológicas macroscópicas como o desaparecimento do pregueamento mucoso característico. CONCLUSÃO: A água gaseificada favoreceu o aumento da área gástrica com conseqüente desaparecimento macroscópico do pregueamento mucoso do órgão, que ocasionou alterações metabólicas da função hepática.

Biomass production and secretion of hydrolytic enzymes are influenced by the structural complexity of the nitrogen source in Fusarium oxysporum and Aspergillus nidulans

The structural complexity of the nitrogen sources strongly affects biomass production and secretion of hydrolytic enzymes in filamentous fungi. Fusarium oxysporum and Aspergillus nidulans were grown in media containing glucose or starch, and supplemented with a nitrogen source varying from a single ammonium salt (ammonium sulfate) to free amino acids (casamino acids), peptides (peptone) and protein (gelatin). In glucose, when the initial pH was adjusted to 5.0, for both microorganisms, higher biomass production occurred upon supplementation with a nitrogen source in the peptide form (peptone and gelatin). With a close to neutrality pH, biomass accumulation was lower only in the presence of the ammonium salt. When grown in starch, biomass accumulation and secretion of hydrolytic enzymes (amylolytic and proteolytic) by Fusarium also depended on the nature of the nitrogen supplement and the pH. When the initial pH was adjusted to 5.0, higher growth and higher amylolytic activities were detected in the media supplemented with peptone, gelatin and casamino acids. However, at pH 7.0, higher biomass accumulation and higher amylolytic activities were observed upon supplementation with peptone or gelatin. Ammonium sulfate and casamino acids induced a lower production of biomass, and a different level of amylolytic enzyme secretion: high in ammonium sulfate and low in casamino acids. Secretion of proteolytic activity was always higher in the media supplemented with peptone and gelatin. Aspergillus, when grown in starch, was not as dependent as Fusarium on the nature of nitrogen source or the pH. The results described in this work indicate that the metabolism of fungi is regulated not only by pH, but also by the level of structural complexity of the nitrogen source in correlation to the carbon source.

Interactions of indole acetic acid with EGF and FSH in the culture of ovine preantral follicles

The mechanisms that regulate the gradual exit of ovarian follicles from the non-growing, primordial pool are very poorly understood. The objective of this study was to evaluate the effects of adding indole acetic acid (IAA), epidermal growth factor (EGF) and follicle stimulating hormone (FSH) to the media for in vitro culture of ovine ovarian fragments and determine their effects on growth activation and viability of preantral follicles. The ovarian cortex was divided into small fragments; one fragment was immediately fixed in Bouin (control). The other fragments were cultured for 2 or 6 days in culture plates with: minimum essential medium (MEM) supplemented with insulin-transferrin-selenium (ITS), pyruvate, glutamine, hypoxantine, bovine serum albumine and antibiotics (MEM+); MEM+ plus IAA (40 ng/mL); MEM+ plus EGF (100 ng/mL); MEM+ plus FSH (100 ng/mL); MEM+ plus IAA + EGF; MEM+ plus IAA + FSH; MEM+ plus EGF + FSH; or MEM+ plus IAA + EGF + FSH. After 2 or 6 days of culture in each treatment, the pieces of ovarian cortex were fixed in Bonin for histological examination. Follicles were classified as primordial or developing (primary and secondary) follicles. Compared to the control, in all media tested, the percentages of primordial follicles were reduced (P < 0.05) and the percentages of developing follicles were increased (P < 0.05) after 2 or 6 days of culture. Furthermore, culture of ovarian cortex for 6 days reduced the percentages of healthy, viable follicles when compared with the control (P < 0.05), except for cultures supplemented with IAA + EGF and EGF + FSH. In conclusion, the addition of IAA and EGF or EGF and FSH to the culture media were the most effective treatments to sustain the health and viability of activated ovine primordial follicles during in vitro culture. (c) 2005 Elsevier B.V. All rights reserved.

Copper resistance of biofilm cells of the plant pathogen Xylella fastidiosa

Xylella fastidiosa is a phytopathogen that causes diseases in different plant species. The development of disease symptoms is associated to the blockage of the xylem vessels caused by biofilm formation. In this study, we evaluated the sensitivity of biofilm and planktonic cells to copper, one of the most important antimicrobial agents used in agriculture. We measured the exopolysaccharides (EPS) content in biofilm and planktonic cells and used real-time reverse transcription polymerase chain reaction to evaluate the expression of the genes encoding proteins involved in cation/multidrug extrusion (acrA/B, mexE/czcA, and metI) and others associated with different copper resistance mechanisms (copB, cutA1, cutA2, and cutC) in the X. fastidiosa biofilm formed in two different media. We confirmed that biofilms are less susceptible to copper than planktonic cells. The amount of EPS seems to be directly related to the resistance and it varies according to the media where the cells are grown. The same was observed for gene expression. Nevertheless, some genes seem to have a greater importance in biofilm cells resistance to copper. Our results suggest a synergistic effect between diffusion barriers and other mechanisms associated with bacterial resistance in this phytopathogen. These mechanisms are important for a bacterium that is constantly under stress conditions in the host.

Ligand Exchange Inducing Efficient Incorporation of CisPt Derivatives into Ureasil-PPO Hybrid and Their Interactions with the Multifunctional Hybrid Network

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of lecithin and soy oil on the fermentative performance of Saccharomyces uvarum I Z 1904

The proposal of this work was to study the effects of lecithin and soy oil on the fermentative performance of Saccharomyces uvarum I Z 1904, a yeast used in the industrial production of ethanol. High Test Molasses (HTM) was chosen as the fermentation media because it is a substratum that is poor in nutrients, and because it permits one to distinguish the action of lipids from other nutritional factors. The study of the optimization of the concentration of lipids by surface response analysis showed that the lipids favor the performance of the yeast principally when applied separately. Maximum concentrations of the two sources of lipids in the media stimulated the budding rate but did not constitute a protection against cell death. Considering the action of lipids on the cellular parameters studied, the supplementation of the media with 3.0 g/l of soy oil permitted the obtention of maximum responses of cellular viability, budding rate and viability of the buds after 6 successive cycles. In relation to the fermentative parameters, the use of 1.5 g/l of soy oil provided high yields and an equilibrium between the mass of ethanol produced (EM) and the alcoholic yield (Y p/s) , whereas the cellular viability after 6 cycles did not differ statistically from that observed with 3g/l of oil.

Recovery of mutans streptococci on MSB, SB-20 and SB-20M agar media

Objective: The recovery of mutans streptococci in saliva and dental biofilm samples depends, in part, on the culture medium used. In this study, we compared (i) the culture media Sucrose-Bacitracin agar (SB-20), Modified SB-20 (SB-20M) and Mitis Salivarius Bacitracin agar (MSB) in the count of colony forming units (cfu) of mutans streptococci and (ii) in the morphological and biochemical differentiation between Streptococcus mutans and Streptococcus sobrinus. Design: Samples of non-stimulated saliva from 20 children were plated on SB-20, SB-20M and MSB, and incubated in microaerophilia at 37 °C for 72 h. Identification of microorganisms was based on analysis of colony morphology under stereomicroscopy. The biochemical identification of colonies was done by biochemical tests using sugar fermentation, resistance to bacitracin and hydrogen peroxide production. Results: There was no significant difference (p > 0.05) in the number of cfu of mutans streptococci recovered on SB-20 and SB-20M agar. Comparing the media, SB-20 and SB-20M yielded a larger number of mutans streptococci colonies (p < 0.05) and were more effective than MSB in the identification of S. sobrinus (p < 0.05), but not of S. mutans (p > 0.05). Conclusion: There was no significant difference between SB-20 and SB-20M culture media in the count of mutans streptococci, demonstrating that the replacement of sucrose by coarse granular cane sugar did not alter the efficacy of the medium. Compared with MSB, SB-20 and SB-20M allowed counting a larger number of mutans streptococci colonies and a more effective morphological identification of S. sobrinus. © 2012 Elsevier Ltd.

Comparative Studies of Bacillus thuringiensis var. israelensis Metabolism in Different Concentrations of Cassava Flour Processing Waste Based Media

Techniques of production of enthomopatogenic bacteria are developed aiming to increase the productivity and to reduce the costs of the fermentative process. Like this, it has been using agroindustrial wastes or by-products as nutrient sources in culture medium, having been used, in this study, the manipueira, a by-product of the processing of the cassava flour. Fermentations were performed in flasks of Erlenmeyer of 500 mL containing 250 mL of culture media, conditioned in shaker at 180 r.p.m. and 28°C, and the media were composed by manipueira, in concentrations that varied between 400 and 1000 mL/L. The time of the process varied between 48 and 120 hours. They appraised the following parameters: cellular growth, the production of spores, the reduction of organic matter (COD analysis) and the variation of reduction sugar. Although there was a proportional cellular growth to the manipueira concentration, the production of spores was similar in all the cases, at the end of the process, in spite of the smallest speed of production of the same ones in the highest concentrations. In relation to the variation of COD, it has, also, a percentile minor of reduction in the highest concentrations. In the analysis of variation of reduction sugars, the higher concentrations are the ones that they present larger slowness in the reduction of this.

Use of HEPG2 cells to assay the safety of cosmetic active substances

The importance of this study is based on the need to obtain simple and efficient in vitro models to predict the in vivo toxicity of cosmetics, aiming not to use animals as experimental model. Here, we proposed the use of HepG2 cells, which are widely applied to simulate the hepatic function of the human organism in vitro. This cell line was chose since recent studies have shown that the liver is potentially the most frequently targeted organ by cosmetic ingredients, and beyond that, considering the widely application of in vitro assays to test the cutaneous permeation of cosmetic products, including the assays applying modified Franz cells, this technique becomes indispensable. Three different cosmetic active substances were used, and the toxicity to HepG2 cells was assessed by the MTT method. The treatment with hyaluronic acid showed no toxicity to HepG2 cells. Treating the cells with P. guajava L. extract were verified that increasing the amount of the extract in the media, the cellular viability decreased, and finally, the treatment of alpha-lipoic acid showed a cytoprotective effect in relation to the treatment with propylene glycol. The study demonstrated the suitability in using HepG2 cells to assess the safety of cosmetic active substances, helping in the prediction of if the substance could be hepatotoxic if could reach the bloodstream

The horn of plenty de McQueen: uma conjunção paródica entre o design, a moda e a arte no contemporâneo

Pós-graduação em Design - FAAC

In search of the autonomous and critical individual: a philosophical and pedagogical analysis of the physical education curriculum of São Paulo (Brazil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

New readers, new reading skills and meaning: challenges for media and information literacy

Recognizing the importance of developing the information and media literacy in contemporary society, this article discusses the scenario of hybrid languages born on cyberspace, hypertext and the new types of readers who interact with information, now disseminated by digital media. As theoretical references authors such as Lucia Santaella, we develop arguments that present the headquarters of language and thought within a semiotic support. Matrices help to understand the phenomenon of hybrid language in hypertext. Therefore, we emphasize that the development of skills associated with the new reading environments propitiated by the virtual environment requires the understanding of language, which is one of the concepts used within the media and information literacy (MIL) proposal of Unesco, which combines the two concepts and skills of information and media literacy. It is hoped that this article motivate scholars and practitioners of education and information to take responsibility to educate for information environments that arise with new media and technologies, emphasizing the issue of reading and language.