Apoptosis Induction in Murine Melanoma (B16F10) Cells by Mannosylerythritol Lipids-B; a Glycolipid Biosurfactant with Antitumoral Activities.

Mannosylerythritol lipids have drawn attention to cosmetic and pharmaceutical industries due to their non-toxicity and excellent biological interactions with human skin, particularly with the deepest epidermal layer. Lamellar liquid crystal structure, formed by MEL-B, is an interesting feature due to its similarity to the stratum corneum molecular arrangement and cell signaling events involved in the deregulation of the cancerous cell membrane. Thus, this work aimed to evaluate the cytotoxicity of commercial mannosylerythritol lipids-B in murine melanoma, fibroblast, and human erythrocytes cells. Cytotoxic effect was more pronounced on the tumor cells from 20 µg/mL, reducing cell viability by 65%, whereas fibroblast and human erythrocytes cells were more resistant to glycolipid treatment. Fluorescence microscopy and flow cytometer proved that mannosylerythritol lipids-B is an apoptosis inducer in tumor cells related to reactive oxygen species generation.

Chromosome variations and diversity of Epidendrum ibaguense Lindl. (Orchidaceae) on the Tepequém's Tepuy, Roraima, Brazil.

Studies addressing chromosome variations have elucidated many points regarding the taxonomy of the Orchidaceae. Epidendrum L. besides being one the largest orchid genera, present remarkable morphological, and inter- and intraspecific chromosome variations. Thus, based on a previous report on flower color variation in individuals of E. ibaguense (magenta, pink, white, and red), our aim was to determine its chromosome number and test whether this trait is associated with flower color variation in natural populations on the Tepequém's Tepuy, Roraima. Root apices were pre-treated with 8-hydroxyquinoline at 4°C for 24 h and subsequently submitted to conventional cytogenetic procedures. Slides with the best spreading and contraction of chromosomes were photographed under light microscopy. Chromosome number was determined by counting at least 10 mitotic metaphase cells per individual. The types of interphase nuclei were determined for 30 nuclei per individual. E. ibaguense presented intra- and interpopulation variation in chromosome number, with 2n = 58, 72, and 76. The chromosome number 2n = 58 was most commonly found in individuals with magenta, pink, and white flowers, while the remaining two chromosome numbers occurred mostly in red-flowered individuals. The types of interphase nuclei were associated with the chromosome number. Individuals with 2n = 58 presented a predominance of semi-reticulated nuclei, while in those with 2n = 72 and 76 the nuclei were predominantly non-reticulated. The dominance of disploidy in E. ibaguense suggests that this cytotype provides this species with a territorial advantage and a higher reproductive success, possibly contradicting the polyploid hypothesis. Our results suggest that chromosome number may not represent a reproductive barrier in genus Epidendrum.

Acerola nectar with added microencapsulated probiotic

The aim of this study was to evaluate the survival of a probiotic microorganism microencapsulated in cellulose acetate phthalate, added to acerola nectar. The changes in pH, Brix, organic acid content and color of the product during its shelf-life were evaluated. A total of 3 processing runs were carried out on a semi-industrial scale, each consisting of a 15-liter batch of acerola nectar with added prebiotics and a microencapsulated probiotic culture. The physicochemical characteristics of the samples remained stable throughout storage. After 30 days storage the acerola nectar samples containing microencapsulated probiotic microorganisms exhibited counts above 8 log CFU per 200 mL, within the limits set by the Brazilian regulation for functional foods. On the other hand, the samples containing...(AU)

Cross-sectional analysis of the implant-abutment interface.

The purpose of this study was to develop a technique to evaluate the implant-abutment gap of an external hexagon implant system as a function of radius. Six implants of 3.75 mm in diameter (Conexao Sistema de Protese Ltda, Sao Paulo, Brazil) and their respective abutments were screw connected and torqued to 20 N cm(-1). The implants were mounted in epoxy assuring an implant long-axis position perpendicular to the vertical axis. Each implant was grounded through its thickness parallel to implant long-axis at six different distance interval. Implant-abutment gap distances were recorded along the implant-abutment region for each section. Individual measurements were related to their radial position through trigonometric inferences. A sixth degree polynomial line fit approach determined radial adaptation patterns for each implant. Micrographs along implant sections showed a approximately 300 mum length implant-abutment engagement region. All implants presented communication between external and internal regions through connection gaps and inaccurate implant-abutment alignment. Average gap distances were not significantly different between implants (P > 0.086). Polynomial lines showed implant-abutment gap values below 10 mum from 0 mum to approximately 250 mum of the implant-abutment engagement region. Gap distances significantly increased from approximately 250 mum to the outer radius of the implant-abutment engagement region. The technique described provided a broader scenario of the implant-abutment gap adaptation compared with previous work concerning implant-abutment gap determination, and should be considered for better understanding mechanical aspects or biological effects of implant-abutment adaptation on peri-implant tissues.

Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions

Extracellular matrix proteins and cell adhesion receptors (integrins) play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as focal adhesion kinase, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight, cysteine-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp) motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.

Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions.

Extracellular matrix proteins and cell adhesion receptors (integrins) play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as focal adhesion kinase, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight, cysteine-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp) motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.

The UASB reactor as an alternative for the septic tank for on-site sewage treatment.

Although septic tanks are amply used for on site sewage treatment, these units have serious drawbacks: the removal efficiency of organic material and suspended solids is low, the units are costly and occupy a large area and operational cost is high due to the need for periodic desludging. In this paper an innovative variant of the UASB reactor is proposed as an alternative for the septic tank. This alternative has several important advantages in comparison with the conventional septic tank: (1) Although the volume of the UASB reactor was about 4 times smaller than the septic tank, its effluent quality was superior, even though small sludge particles were present, (2) desludging of the UASB reactor is unnecessary and even counterproductive, as the sludge mass guarantees proper performance, (3) the UASB reactor is easily transportable (compact and light) and therefore can be produced in series, strongly reducing construction costs and (4) since the concentration of colloids in the UASB effluent is much smaller than in the ST effluent, it is expected that the infiltration of the effluent will be much less problematic.

Virulence of Sporothrix schenckii conidia and yeast cells, and their susceptibility to nitric oxide.

The involvement of nitric oxide (NO) in macrophage (M phi) fungicidal activity against Sporothrix schenckii, and the relationship between NO susceptibility and the differential virulence of conidia and yeast cells, were investigated. Confirming a previously reported correlation between the length of time in culture and virulence of S. schenckii, conidia isolated from 12-day mycelial cultures (Ss-12) were less virulent to mice than conidia from 7-day cultures (Ss-7) or yeast cells. Indicative of NO production, infected animals showed a significant increase in serum levels of nitrite that was lower in mice infected with Ss-12 than in mice infected with Ss-7 or yeast. Stimulation of murine M phi with interferon-gamma (IFN-gamma) induced NO production and inhibition of fungal growth. The cytotoxic activity of M phi against Ss-12 was significantly greater than against Ss-7 or yeast cells, the highly virulent fungal forms. The addition of NO synthase inhibitors abrogated M phi cytotoxic activity against all fungal forms. The phagocytic activity of M phi against Ss-7 was significantly lower than against Ss-12 or yeast cells. Although the ingestion of fungal cells triggered the oxidative burst in M phi, the fungicidal activity was not altered in the presence of superoxide dismutase (SOD) and catalase. In addition, Ss-12 and yeast cells were more susceptible than Ss-7 to the direct fungicidal activity of the NO donors S-nitroso-N-acetyl-DL-penicillamine (SNAP), S-nitrosoglutathione (GSNO) and 3-morpholinosydnonimine (SIN-1). The results of this study indicate that NO is a key cytotoxic mediator involved in the murine M phi defence against S. schenckii, and that the virulence of Ss-7, Ss-12 and yeast cells may be related to a differential susceptibility to NO.

Effects of jarastatin, a novel snake venom disintegrin, on neutrophil migration and actin cytoskeleton dynamics.

A new disintegrin, an RGD-containing peptide of 6 kDa called jarastatin, was purified from Bothrops jararaca venom. It is a potent inhibitor of platelet aggregation induced by ADP, collagen, and thrombin. The effect of jarastatin on neutrophil migration in vivo and in vitro and on the actin cytoskeleton dynamics of these cells was investigated. Incubation in vitro with jarastatin significantly inhibited, in a concentration-dependent manner, the chemotaxis of human neutrophils toward fMLP, IL-8, and jarastatin itself. Despite this inhibitory effect, jarastatin induced neutrophil chemotaxis. A significant increase of F-actin content was observed in jarastatin-treated neutrophils. Furthermore, as demonstrated by confocal microscopy after FITC-phalloidin labeling, these cells accumulated F-actin at the plasmalemma, a distribution similar to that observed in fMLP-stimulated cells. Pretreatment of mice with jarastatin inhibited neutrophil migration into peritoneal cavities induced by carrageenan injection. The results suggest that binding of jarastatin to neutrophil integrins promotes cellular activation and triggers a dynamic alteration of the actin filament system and that this is one of the first event in integrin-mediated signaling.

Evaluation of temporal, seasonal and geographic stability of the molluscicidal property of Euphorbia splendens latex.

Laboratory tests with aqueous solutions of Euphorbia splendens var. hislopii latex have demonstrated seasonal stability of the molluscacidal principle, with LD90 values of 1.14 ppm (spring), 1.02 ppm (fall), 1.09 ppm (winter), and 1.07 ppm (summer) that have been determined against Biomphalaria tenagophila in the field. Assays on latex collected in Belo Horizonte and Recife yielded LD90 values similar to those obtained with the reference substance collected in Rio de Janeiro (Ilha do Governador), demonstrating geographic stability of the molluscacidal effect. The molluscacidal action of aqueous dilutions of the latex in natura, centrifuged (precipitate) and lyophilized, was stable for up to 124 days at room temperature (in natura) and for up to 736 days in a common refrigerator at 10 to 12 degrees C (lyophilized product). A 5.0 ppm solution is 100% lethal for snails up to 13 days after preparation, the effect being gradually lost to almost total inactivity by the 30th day. This observation indicated that the active principle is instable. These properties together with the wide distribution of the plant, its resistance and adaptation to the tropical climate, its easy cultivation and the easy obtention of latex and preparation of the molluscicidal solution, make this a promising material for large-scale use in the control of schistosomiasis.