Rheological behavior, zeta potential, and accelerated stability tests of Buriti oil (Mauritia flexuosa) emulsions containing lyotropic liquid crystals

Background: It is well known that the Amazon region presents a huge biodiversity; therefore, countless natural resources are being employed in the production of phytocosmetics and phytomedicines. Objective: The purpose of this work was to obtain emulsions produced with Buriti oil and nonionic surfactants. Methods: Two surfactant systems were employed (Steareth-2 associated to Ceteareth-5 and to Ceteareth-20) to produce the emulsions using phase diagram method. Emulsions were obtained by echo-planar imaging method at 75 degrees C. Rheological behavior and zeta potential were evaluated, and accelerated stability tests were performed. Results: All emulsions analyzed presented pseudoplastic behavior. Zeta potential values were obtained between -14.2 and -53.3 mV. The formulations did not show changes in either physical stability, pH, or rheological behavior after accelerated stability tests. Significant differences were observed only after temperature cycling test. Conclusion: Based on these results, the emulsions obtained could be considered as promising delivery systems.

The effects of dietary supplementation of methionine on genomic stability and p53 gene promoter methylation in rats

Methionine is a component of one-carbon metabolism and a precursor of S-adenosylmethionine (SAM), the methyl donor for DNA methylation. When methionine intake is high, an increase of S-adenosylmethionine (SAM) is expected. DNA methyltransferases convert SAM to S-adenosylhomocysteine (SAH). A high intracellular SAH concentration could inhibit the activity of DNA methyltransferases. Therefore, high methionine ingestion could induce DNA damage and change the methylation pattern of tumor suppressor genes. This study investigated the genotoxicity of a methionine-supplemented diet. It also investigated the diet`s effects on glutathione levels, SAM and SAH concentrations and the gene methylation pattern of p53. Wistar rats received either a methionine-supplemented diet (2% methionine) or a control diet (0.3% methionine) for six weeks. The methionine-supplemented diet was neither genotoxic nor antigenotoxic to kidney cells, as assessed by the comet assay. However, the methionine-supplemented diet restored the renal glutathione depletion induced by doxorubicin. This fact may be explained by the transsulfuration pathway, which converts methionine to glutathione in the kidney. Methionine supplementation increased the renal concentration of SAH without changing the SAM/SAH ratio. This unchanged profile was also observed for DNA methylation at the promoter region of the p53 gene. Further studies are necessary to elucidate this diet`s effects on genomic stability and DNA methylation. (C) 2011 Elsevier ay. All rights reserved.

Structure determination of the three disulfide bond isomers of alpha-conotoxin GI: A model for the role of disulfide bonds in structural stability

The three possible disulfide bonded isomers of alpha-conotoxin GI have been selectively synthesised and their structures determined by H-1 NMR spectroscopy. alpha-Conotoxin GI derives from the venom of Conus geographus and is a useful neuropharmacological tool as it selectively binds to the nicotinic acetylcholine receptor (nAChR), a ligand-gated ion channel involved in nerve signal transmission. The peptide has the sequence ECCNPACGRHYSC-NH2, and the three disulfide bonded isomers are referred to as GI(2-7;3-13), GI(2-13;3-7) and GI(2-3;7-13). The NMR structure for the native isomer GI(2-7;3-13) is of excellent quality, with a backbone pairwise RMSD of 0.16 Angstrom for a family of 35 structures, and comprises primarily a distorted 3(10),, helix between residues 5 to 11. The two non-native isomers exhibit multiple conformers in solution, with the major populated forms being different in structure both from each other and from the native form. Structure-activity relationships for the native GI(2-7;3-13) as well as the role of the disulfide bonds on folding and stability of the three isomers are examined. It is concluded that the disulfide bonds in alpha-conotoxin GI play a crucial part in determining both the structure and stability of the peptide. A trend for increased conformational heterogeneity was observed in the order of GI(2-7;3-13) < GI(2-13;3-7) < GI(2-3;7-13). It was found that the peptide bond joining Cys2 to Cys3 in GI(2-3;7-13) is predominantly trans, rather than cis as theoretically predicted. These structural data are used to interpret the varying nAChR binding of the non-native forms. A model for the binding of native GI(2-7;3-13) to the mammalian nAChR is proposed, with an alpha-subunit binding face made up of Cys2, Asn4, Pro5, Ala6 and Cys7 and a selectivity face, comprised of Arg9 and His10. These two faces orient the molecule between the alpha and delta subunits of the receptor. The structure of the CCNPAC sequence of the native GI(2-7;3-13) is compared to the structure of the identical sequence from the toxic domain of heat-stable enterotoxins, which forms part of the receptor binding region of the enterotoxins, but which has a different disulfide connectivity. (C) 1998 Academic Press Limited.

Lateral open bite: Treatment and stability

Because of their multifactorial etiologies, dental and skeletal open bites are among the most difficult malocclusions to treat to a successful and stable result. Etiologic factors include vertical maxillary excess, skeletal pattern, abnormalities in dental eruption, and tongue-thrust problems. The purpose of this article was to report the treatment of an adult patient with a lateral open bite and a unilateral posterior crossbite. The treatment involved nonextraction therapy, including intermaxillary elastics, to obtain dentoalveolar extrusion in the region of the lateral open bite. The treatment results were successful and remained stable 2 years later. (Am J Orthod Dentofacial Orthop 2010;137:701-11)

Dynamical Stability and Predictability of Football Players: The Study of One Match

The game of football demands new computational approaches to measure individual and collective performance. Understanding the phenomena involved in the game may foster the identification of strengths and weaknesses, not only of each player, but also of the whole team. The development of assertive quantitative methodologies constitutes a key element in sports training. In football, the predictability and stability inherent in the motion of a given player may be seen as one of the most important concepts to fully characterise the variability of the whole team. This paper characterises the predictability and stability levels of players during an official football match. A Fractional Calculus (FC) approach to define a player’s trajectory. By applying FC, one can benefit from newly considered modeling perspectives, such as the fractional coefficient, to estimate a player’s predictability and stability. This paper also formulates the concept of attraction domain, related to the tactical region of each player, inspired by stability theory principles. To compare the variability inherent in the player’s process variables (e.g., distance covered) and to assess his predictability and stability, entropy measures are considered. Experimental results suggest that the most predictable player is the goalkeeper while, conversely, the most unpredictable players are the midfielders. We also conclude that, despite his predictability, the goalkeeper is the most unstable player, while lateral defenders are the most stable during the match.

Color change using HSB color system of dental resin composites immersed in different common Amazon region beverages

The purpose of this study is to evaluate in vitro the color stability of composite resins when exposed to beverages with high coloring contents from the Amazon region. 240 samples from four different composite brands (Natural Look, Z350, 4Seasons and Opallis) of hue A3 were fabricated using an acrylic matrix. The samples were stored in distilled water at 37ºC for 24 hours. The initial color (T0) was registered using a Canon EOS Rebel XTi 10 mp camera, and then the samples were divided into four groups (n=15): G1 (coffee), G2 (açaí juice), G3 (energetic guaraná) and G4 (control - distilled water). The samples were exposed to solutions of DES (6hs) and RE (18hs) and placed in a double boiler under constant agitation, at 37ºC for 30 days. The samples were immersed in the coloring solutions for 15 minutes daily. After 7, 15 and 30 days, new photographic registers were made (T1, T2 and T3). The images were analyzed using Corel PHOTO-PAINT 12 software to identify the colors through the HSB system. The Kruskal-Wallis and t tests (p<0.05) demonstrated significant differences in color (hue, saturation and brightness). The results revealed that none of the tested composites showed color stability when exposed to coloring solutions, and that the Amazon region beverages (açaí juice and energetic guaraná) showed to be less coloring than coffee.

Genetic Variability and Microdistribution of Triatoma infestans Genotypes and Trypanosoma cruzi Clones in Arequipa Region (Peru)

The genetic variability of Triatoma infestans and Trypanosoma cruzi populations was studied by isoenzyme analysis in two distinct areas of Arequipa province (Peru); one, Santa Rita de Siguas, being an endemic area for Chagas' disease, the second, Arequipa, recently infected. Analysis of T. infestans genetic variability indicates, (i) temporal stability of genotypes found in Santa Rita de Siguas, (ii) high genetic differences between Arequipa and Santa Rita de Siguas populations suggesting minor contact between them, (iii) multiple origin of the T. infestans population in Arequipa, and (iv) poor dispersal capacity of T. infestans: the panmictic unit could be reduce to a house. Parasite isoenzyme analysis was performed in 29 Peruvian stocks of T. cruzi, mainly isolated from bugs taken in a single locality, Santa Rita de Siguas. The results show, (i) a high genetic polymorphism, (ii) nine different multilocus genotypes were detected and clustered in two different clades, (iii) most of the parasite isolates pertained to one of the clade and were genetically similar to those analyzed 12 years before. This sample allowed the study of the mating system of T. cruzi in strict sympatic conditions and gave more strength to the hypothesis of the clonal structure of T. cruzi populations

Catabolic ornithine carbamoyltransferase of Pseudomonas aeruginosa. Importance of the N-terminal region for dodecameric structure and homotropic carbamoylphosphate cooperativity.

Pseudomonas aeruginosa has an anabolic (ArgF) and a catabolic (ArcB) ornithine carbamoyltransferase (OTCase). Despite extensive sequence similarities, these enzymes function unidirectionally in vivo. In the dodecameric catabolic OTCase, homotropic cooperativity for carbamoylphosphate strongly depresses the anabolic reaction; the residue Glu1O5 and the C-terminus are known to be essential for this cooperativity. When Glu1O5 and nine C-terminal amino acids of the catabolic OTCase were introduced, by in vitro genetic manipulation, into the closely related, trimeric, anabolic (ArgF) OTCase of Escherichia coli, the enzyme displayed Michaelis-Menten kinetics and no cooperativity was observed. This indicates that additional amino acid residues are required to produce homotropic cooperativity and a dodecameric assembly. To localize these residues, we constructed several hybrid enzymes by fusing, in vivo or in vitro, the E. coli argF gene to the P. aeruginosa arcB gene. A hybrid enzyme consisting of 101 N-terminal ArgF amino acids fused to 233 C-terminal ArcB residues and the reciprocal ArcB-ArgF hybrid were both trimers with little or no cooperativity. Replacing the seven N-terminal residues of the ArcB enzyme by the corresponding six residues of E. coli ArgF enzyme produced a dodecameric enzyme which showed a reduced affinity for carbamoylphosphate and an increase in homotropic cooperativity. Thus, the N-terminal amino acids of catabolic OTCase are important for interaction with carbamoylphosphate, but do not alone determine dodecameric assembly. Hybrid enzymes consisting of either 26 or 42 N-terminal ArgF amino acids and the corresponding C-terminal ArcB residues were both trimeric, yet they retained some homotropic cooperativity. Within the N-terminal ArcB region, a replacement of motif 28-33 by the corresponding ArgF segment destabilized the dodecameric structure and the enzyme existed in trimeric and dodecameric states, indicating that this region is important for dodecameric assembly. These findings were interpreted in the light of the three-dimensional structure of catabolic OTCase, which allows predictions about trimer-trimer interactions. Dodecameric assembly appears to require at least three regions: the N- and C-termini (which are close to each other in a monomer), residues 28-33 and residues 147-154. Dodecameric structure correlates with high carbamoylphosphate cooperativity and thermal stability, but some trimeric hybrid enzymes retain cooperativity, and the dodecameric Glu1O5-->Ala mutant gives hyperbolic carbamoylphosphate saturation, indicating that dodecameric structure is neither necessary nor sufficient to ensure cooperativity.

PAP1 [poly(A) polymerase 1] homozygosity and hyperadenylation are major determinants of increased mRNA stability of CDR1 in azole-resistant clinical isolates of Candida albicans.

Using genetically matched azole-susceptible (AS) and azole-resistant (AR) clinical isolates of Candida albicans, we recently demonstrated that CDR1 overexpression in AR isolates is due to its enhanced transcriptional activation and mRNA stability. This study examines the molecular mechanisms underlying enhanced CDR1 mRNA stability in AR isolates. Mapping of the 3' untranslated region (3' UTR) of CDR1 revealed that it was rich in adenylate/uridylate (AU) elements, possessed heterogeneous polyadenylation sites, and had putative consensus sequences for RNA-binding proteins. Swapping of heterologous and chimeric lacZ-CDR1 3' UTR transcriptional reporter fusion constructs did not alter the reporter activity in AS and AR isolates, indicating that cis-acting sequences within the CDR1 3' UTR itself are not sufficient to confer the observed differential mRNA decay. Interestingly, the poly(A) tail of the CDR1 mRNA of AR isolates was approximately 35-50 % hyperadenylated as compared with AS isolates. C. albicans poly(A) polymerase (PAP1), responsible for mRNA adenylation, resides on chromosome 5 in close proximity to the mating type-like (MTL) locus. Two different PAP1 alleles, PAP1-a/PAP1-alpha, were recovered from AS (MTL-a/MTL-alpha), while a single type of PAP1 allele (PAP1-alpha) was recovered from AR isolates (MTL-alpha/MTL-alpha). Among the heterozygous deletions of PAP1-a (Deltapap1-a/PAP1-alpha) and PAP1-alpha (PAP1-a/Deltapap1-alpha), only the former led to relatively enhanced drug resistance, to polyadenylation and to transcript stability of CDR1 in the AS isolate. This suggests a dominant negative role of PAP1-a in CDR1 transcript polyadenylation and stability. Taken together, our study provides the first evidence, to our knowledge, that loss of heterozygosity at the PAP1 locus is linked to hyperadenylation and subsequent increased stability of CDR1 transcripts, thus contributing to enhanced drug resistance.

Entrained macrocryst minerals as a key to the source region of olivine nephelinites: Humberg, Kaiserstuhl, Germany

Olivine nephelinites commonly contain macrocrysts of olivine and clinopyroxene. Some of these macrocrysts might represent fragments of the source region of the host magma transported to the Earth surface. If this hypothesis is correct these fragments can be used to characterize the composition of the source region and to put constraints on the magma generation process. In this study, we investigate the origin of macrocrysts and mineral aggregates from an olivine nephelinite from the Kaiserstuhl, Germany. We focus on clinopyroxenes (Cpx), which can be divided into three groups. Cpx I is relict Cpx from aggregates with deformed olivine that is depleted in Ca and characterized by strong light rare earth element (LREE) fractionation, low Ti/Eu and negative high field strength element (HFSE) anomalies. Its geochemical signature is consistent with formation by carbonatite metasomatism and with equilibration in the Presence of orthopyroxene. Cpx II is Ca-rich Cpx, forming both aggregates with deformed olivine and individual macrocrysts. The LREE, as for Cpx I, are strongly fractionated. Convex REE patterns may be present. The depletion in HFSE is less pronounced. Cpx III is oscillatory zoned Cpx phenociysis showing enrichment in Ca, convex REE patterns and no HFSE anomalies. The transition in the trace element abundances between the Cpx of the three groups is gradual. However, Cpx I and H did not crystallize from the host magma, as demonstrated by the presence of kink-bands and undulose extinction in the associated olivine and by the composition of alkali aluminosilicate glass inclusions in Cpx H. Based on the Cpx relationships, we interpret the studied suite of macrocrysts and mineral aggregates as a mixture of disintegrated fragments of the source region of the host olivine nephelinite. The process of melt generation was multi-stage. A primary carbonatite melt ascending from deeper levels in the mantle, probably from the dolomite-garnet peridotite stability field, reacted with mantle peridotite along the solidus ledge in the system lherzolite-CO2 (< 20-22 kbar) and started to crystallize carbonate minerals. Because of its low solidus temperature, the resulting carbonate-wehrlite assemblage melted incongruently with the formation of additional clinopyroxene. The carbonatite melt evolved during crystallization of carbonate minerals and concomitant incongruent melting of the carbonate-wehrlite, accompanied by the segregation of incipient alkali aluminosilicate melts. As a consequence of fast reaction rates in the presence of a carbonatite melt, this process probably took place under disequilibrium conditions. Further melting of the assemblage wehrlite + alkali aluminosilicate melt led to the generation of the olivine nephelinite magma. It entrained fragments of the wehrlite and brought them to the surface.

Fatty acids regulate Thy-1 antigen mRNA stability in T lymphocyte precursors.

In this study, we report the effect of fatty acids on the Thy-1 antigen mRNA decay. Low serum and synthetic medium culture conditions were used to demonstrate that fatty acids, which are important metabolites involved as second messengers in signal transduction, also influence the steady-state mRNA level. Detailed analysis demonstrated that polyunsaturated lipids attached to bovine serum albumin, such as linoleic, linolenic, and arachidonic acids, modulate gene expression specifically in the S1A T lymphoma cell line by inducing a 3-5-fold increase in the steady-state Thy-1 mRNA level, concomitant with a twofold increase in cell surface expression. A similar modulation was observed in the immature CD4-CD8- T cell precursors but not in mature thymocytes. Nuclear run-on and transfection experiments indicated that the observed Thy-1 mRNA level is post-transcriptionally regulated and that the presence of the coding region is sufficient for this adaptive response. A mechanism without a requirement for protein kinase C activation, but involving Ca2+ entry, could account for this difference in Thy-1 mRNA stability.

PCAF regulates the stability of the transcriptional regulator and cyclin-dependent kinase inhibitor p27Kip1

P27(Kip1) (p27) is a member of the Cip/Kip family of cyclin-dependent kinase inhibitors. Recently, a new function of p27 as transcriptional regulator has been reported. It has been shown that p27 regulates the expression of target genes mostly involved in splicing, cell cycle, respiration and translation. We report here that p27 directly binds to the transcriptional coactivator PCAF by a region including amino acids 91-120. PCAF associates with p27 through its catalytic domain and acetylates p27 at lysine 100. Our data showed that overexpression of PCAF induces the degradation of p27 whereas in contrast, the knockdown of PCAF stabilizes the protein. A p27 mutant in which K100 was substituted by arginine (p27-K100R) cannot be acetylated by PCAF and has a half-life much higher than that of p27WT. Moreover, p27-K100R remains stable along cell-cycle progression. Ubiquitylation assays and the use of proteasome inhibitors indicate that PCAF induces p27 degradation via proteasome. We also observed that knockdown of skp2 did not affect the PCAF induced degradation of p27. In conclusion, our data suggest that the p27 acetylation by PCAF regulates its stability.

Donor site morbidity of the posterior conchal region.

BACKGROUND: The perichondral cutaneous graft (PCCG) from the posterior conchal region is an elegant solution for the coverage of facial defects with particular stability requirements. The donor defect can easily be covered with a transposition flap from the postauricular region. Although this region is a common donor site for skin grafts and has an important supporting function for glasses or hearing aids, little is known about long-term morbidity after graft harvest. OBJECTIVE: To assess the morbidity of the posterior concha and the postauricular region in terms of pain, scar formation, and patient satisfaction. MATERIALS AND METHODS: A retrospective study of 16 patients who had a PCCG harvested from the posterior concha. RESULTS: Two patients presented with a postoperative wound dehiscence on the postauricular region and one with a keloid scar on the posterior concha. One case of transitory hyperesthesia and pain when sleeping on the operated site was observed. None had complaints related to wearing glasses or hearing aids. CONCLUSION: Donor site morbidity of the postauricular and posterior conchal region is minimal and associated with high patient satisfaction, excellent aesthetic results, and emotional detachment from the hidden donor site.

Humic Haplustox under different land uses in a high altitude environment in the Agreste region of Pernambuco, Brazil

The Garanhuns Plateau in the Agreste region of the State of Pernambuco, Brazil is characterized by humid climatic conditions due to orographic rains, unlike the surrounding semiarid region. These soils are subjected to intense agricultural use and are extremely important for the regional economy. This study was carried out in the municipality of Brejão in the Agreste region with the aim of assessing changes in humic Haplustox soils subjected to different land uses. Four plots with different vegetation covers (native forest, secondary shrubby vegetation (capoeira), traditional cropping system, and planted pasture) were selected, and samples were taken from a soil profile and four small pits surrounding it at each site. Physical and chemical properties were assessed, including aggregate stability, humic organic fractions, and a microbiological evaluation through determination of basal respiration, microbial biomass carbon, and metabolic quotient. The soils under study showed physical and chemical properties typical of a Haplustox, such as low nutrient content, low cation exchange capacity, and high levels of acidity and Al saturation. The total organic carbon (TOC) contents were high regardless of the type of land use. Aggregates < 2 mm were dominant in all the conditions under study. The TOC content was higher in the soil under capoeira, 43.91 g kg-1 on the surface, while 34.36 and 33.43 g kg-1 of TOC were observed in the first layer of forest and pasture soils, respectively. While the microbial biomass C (MBC) was greater than 700 mg kg-1 in the forest and pasture areas (in the 0-5 cm layer), and 588 mg kg-1 in the soil under capoeira, these numbers were not statistically different. In the cultivated soil area, there was a reduction of around 28 % in TOC and MBC contents. Agricultural activity contributed to degradation of the humic horizon, as can be seen from a significant decrease in the TOC and changes in the relative distribution of the humic fractions. In contrast, aggregate stability was not altered as a function of the different land uses; the soil under planted pasture and capoeira were similar to the soil under native forest. Humin was the most important humified fraction for C reserves, contributing over 40 % of the TOC in these soils.

Aggregate stability by the "high energy moisture characteristic" method in an oxisol under differentiated management

Studies testing the High Energy Moisture Characteristic (HEMC) technique in tropical soils are still incipient. By this method, the effects of different management systems can be evaluated. This study investigated the aggregation state of an Oxisol under coffee with Brachiaria between crop rows and surface-applied gypsum rates using HEMC. Soil in an experimental area in the Upper São Francisco region, Minas Gerais, was studied at depths of 0.05 and 0.20 m in coffee rows. The treatments consisted of 0, 7, and 28 Mg ha-1 of agricultural gypsum rates distributed on the soil surface of the coffee rows, between which Brachiaria was grown and periodically cut, and compared with a treatment without Brachiaria between coffee rows and no gypsum application. To determine the aggregation state using the HEMC method, soil aggregates were placed in a Büchner funnel (500 mL) and wetted using a peristaltic pump with a volumetric syringe. The wetting was applied increasingly at two pre-set speeds: slow (2 mm h-1) and fast (100 mm h-1). Once saturated, the aggregates were exposed to a gradually increasing tension by the displacement of a water column (varying from 0 to 30 cm) to obtain the moisture retention curve [M = f (Ψ) ], underlying the calculation of the stability parameters: modal suction, volume of drainable pores (VDP), stability index (slow and fast), VDP ratio, and stability ratio. The HEMC method conferred sensitivity in quantifying the aggregate stability parameters, and independent of whether gypsum was used, the soil managed with Brachiaria between the coffee rows, with regular cuts discharged in the crop row direction, exhibited a decreased susceptibility to disaggregation.