Enhanced stabilization of aerosol-OT surfactant monolayer upon interaction with small amounts of bovine serum albumin at the air-water interface

An investigation is made of the influence from small amounts of the protein bovine serum albumin (BSA) on the lateral organization of low molecular weight surfactant sodium bis-2-ethylhexyl sulfosuccinate (AOT) at the air-water interface. Surface pressure (pi - A), surface potential (DeltaV - A) and Brewster angle microscopy (BAM) experiments were carried out, with particular emphasis on the monolayer stability under successive compression-expansion cycles. AOT monolayer is not stable at the air-water interface, which means that the majority of AOT molecules go into the aqueous subphase as monomers and/or normal micelles. When a waiting time elapses between spreading and compression, the surfactant monolayer tends to reorganize partially at the air-water interface, with a monolayer expansion being observed for waiting times as large as 12 h. The incorporation of very small amount of BSA (10(-9) M) at the interface, also inferred from BAM, increases the monolayer stability as revealed by pi - A and DeltaV - A results. For a waiting time of circa 3 h, the mixed monolayer reaches its maximum stability. This must be related to protein (and/or protein-surfactant complexes) adsorbed onto the AOT monolayer, thus altering the BSA conformation to accommodate its hydrophobic/hydrophilic residues. Furthermore, the effects from such small amounts of BSA in the monolayer formation and stabilization mean that the AOT monolayer responds cooperatively to BSA. (C) 2004 Elsevier B.V. All rights reserved.

Interaction of small amounts of bovine serum albumin with phospholipid monolayers investigated by surface pressure and atomic force microscopy

The influence of small amounts of bovine serum albumin (BSA) (nM concentration) on the lateral organization of phospholipid monolayers at the air-water interface and transferred onto solid substrates as one-layer Langmuir-Blodgett (LB) films was investigated. The kinetics of adsorption of BSA onto the phospholipid monolayers was monitored with surface pressure isotherms in a Langmuir trough, for the zwitterionic dipalmitoylphosphatidyl ethanolamine (N,N-dimethyl-PE) and the anionic dimyristoylphosphatidic acid (DMPA). A monolayer of N,N-dimethyl-PE or DMPA incorporating BSA was transferred onto a solid substrate using the Langmuir-Blodgett technique. Atomic force microscopy (AFM) images of one-layer LB films displayed protein-phospholipid domains, whose morphology was characterized using dynamic scaling theories to calculate roughness exponents. For DMPA-BSA films the surface is characteristic of self-affine fractals, which may be described with the Kardar-Parisi-Zhang (KPZ) equation. on the other hand, for N,N-dimethyl-PE-BSA films, the results indicate a relatively flat surface within the globule. The height profile and the number and size of globules varied with the type of phospholipid. The overall results, from kinetics of adsorption on Langmuir monolayers and surface morphology in LB films, could be interpreted in terms of the higher affinity of BSA to the anionic DMPA than to the zwitterionic N,N-dimethyl-PE. Furthermore, the effects from such small amounts of BSA in the monolayer point to a cooperative response of DMPA and N,N-dimethyl-PE monolayers to the protein. (c) 2005 Elsevier B.V. All rights reserved.

Fermented soy product supplemented with isoflavones affects adipose tissue in a regional-specific manner and improves HDL-cholesterol in rats fed on a cholesterol-enriched diet

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

Effect of ingestion of soy yogurt on intestinal parameters of rats fed on a beef-based animal diet

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

Efficiency of intermittent exercise on adiposity and fatty liver in rats fed with high-fat diet

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

Effect of fermented soy product on the fecal microbiota of rats fed on a beef-based animal diet

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

Effects of probiotic bacteria, isoflavones and simvastatin on lipid profile and atherosclerosis in cholesterol-fed rabbits: a randomized double-blind study

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

Soy beta-Conglycinin (7S Globulin) Reduces Plasma and Liver Cholesterol in Rats Fed Hypercholesterolemic Diet

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

beta-Conglycinin (7S) and glycinin (11S) exert a hypocholesterolemic effect comparable to that of fenofibrate in rats fed a high-cholesterol diet

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mapping of quantitative trait loci controlling tick [Riphicephalus (Boophilus) microplus] resistance on bovine chromosomes 5, 7 and 14

Differences in domestication and selection processes have contributed to considerable phenotypic and genotypic differences between Bos taurus and Bos indicus cattle breeds. of particular interest in tropical and subtropical production environments are those genetic differences between subspecies that underlie the phenotypic extremes in tolerance and susceptibility to parasite infection. In general, B. taurus cattle are more susceptible to ectoparasites than B. indicus cattle in tropical environments, and much of this difference is under genetic control. To identify genomic regions involved in tick resistance, we developed a B. taurus x B. indicus F-2 experimental population to map quantitative trait loci (QTL) for resistance to the Riphicephalus (Boophilus) microplus tick. About 300 individuals were measured for parasite load in two seasons (rainy and dry) and genotyped for 23 microsatellite markers covering chromosomes 5, 7 and 14. We mapped a suggestive chromosome-wide QTL for tick load in the rainy season (P < 0.05) on chromosome 5. For the dry season, suggestive (P < 0.10) chromosome-wide QTL were mapped on chromosomes 7 and 14. The additive effect of the QTL on chromosome 14 corresponds to 3.18% of the total observed phenotypic variance. Our QTL-mapping study has identified different genomic regions controlling tick resistance; these QTL were dependent upon the season in which the ticks were counted, suggesting that the QTL in question may depend on environmental factors.

Antiviral effect of Guazuma ulmifolia and Stryphnodendron adstringens on poliovirus and bovine herpesvirus

Crude extract (CE) and aqueous (AqF) and ethyl acetate (EtOAcF) fractions of Guazuma ulmifolia LAM., Sterculiaceae and the corresponding AqF, EtOAcF of Stryphnodendron adstringens (MART.) COVILLE, Leguminosae were tested for their antiviral activity against poliovirus 1 (P-1) and bovine herpesvirus 1 (BHV-1) in HEp2 cultured cells. The antiviral activity was monitored by plaque assay and immunolluorescence assay (IFA) under virucidal and therapeutic protocols. The therapeutic protocol demonstrated statistically significant positive results with both plants and for both virus strains. The highest percentages of viral inhibition were found for G. ulmifolia EtOAcF which inhibited BHV-1 and P-1 replication by 100% and 99%, respectively (p < 0.05, Student's t-test). For S. adstringens, AqF was the most efficient, inhibiting BHV-1 and P-1 by 97% and 93%, respectively (p < 0.05). In the virucidal protocol, G. ulmifolia CE inhibited the replication of BHV-1 and P-1 by 60% and 26%, respectively (p < 0.05), while, for S. adstringens, inhibition of 62% (p < 0.05) was demonstrated only with EtOAcF for P-1. IFA demonstrated that the greatest reduction in fluorescent cell number occurred with G. ulmifolia, under the therapeutic protocol for both virus strains. However, AqF and EtOAcF of S. adstringens were most efficient with the virucidal protocol for P-1 In conclusion, we demonstrated that G. ulmifolia and S. adstringens inhibited BHV-1 and P-1 replication, as well as, blocked the synthesis of viral antigens in infected cell cultures.

Effectiveness of Photogem (R) activated by LED on the decontamination of artificial carious bovine dentin

The aim of this study was the evaluation of the effectiveness of photodynamic therapy on the decontamination of artificially induced carious bovine dentin, using Photoge(R) as the photosensitizer agent and an LED device as a light source. Dentin samples obtained from bovine incisors were immersed in sterile broth supplemented by Lactobacillus acidophillus 10(8) colony formation units (CFU) and Streptococcus mutans 10 8 CFU. Different concentrations of photosensitizer, PA = 1 mg/ml, PB = 2 mg/ml, and PC = 3 mg/ml, and two fluences, D = 24 J/cm(2) and D = 48 J/cm(2), were investigated. After CFU counting per milligram of carious dentin and statistical analysis, we observed that the photodynamic therapy (PDT) parameters used were effective for bacterial reduction in the in vitro model under study. The best result was achieved with the application of Photoge(R) at 2 mg/ml and photoactivated under 24 J/cm(2) showing a survival factor of 0.14. At higher photosensitizer concentrations, a higher dark toxicity was observed. We propose a simple mathematical expression for the determination of PDT parameters of photosensitizer concentration and light fluence for different survival factor values. Since LED devices are simpler and cheaper compared to laser systems, it would be interesting to verify their efficacy as a light source in photodynamic therapy for the decontamination of carious dentin.

Bovine pericardium retail preserved in glutaraldehyde and used as a vascular patch

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

Effects of swim training on liver carcinogenesis in male Wistar rats fed a low-fat or high-fat diet

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