Morse basis expansion applied to diatomic molecules

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

Efeitos tóxicos de surfactantes fitossanitários para o peixe mato grosso (Hyphessobrycon eques)

Toxic effects of phytosanitary surfactants for jewel tetra (Hyphessobrycon eques). Surfactants are amphipatic molecules that reduce the surface tension of water and make up the inert components of pesticide formulations. Thus, the objectives of this study were: to estimate the lethal concentration (LC(I)50;96h); classify and evaluate water quality during testing of the following surfactants: Agral[registered trademark], Aterbane[registered trademark]BR, Ag-bem[registered trademark], Energic[registered trademark], Fixade[registered trademark] and Gotafix[registered trademark] for jewel tetra (Hyphessobrycon eques); and the signs of intoxication in the animals. For this, the fish were acclimated for ten days in the bioassay room. The animals were exposed to the surfactants in an entirely randomized design with three replications. The LC(I)(50;96h) of surfactant Agral[registered trademark] was 3.29 mg L-1; Aterbane[registered trademark] BR 8.21 mg L-1; Energic[registered trademark] 2.34 mg L-1; Gotafix[registered trademark] 4.37 mg L-1; Fixade[registered trademark] 3.38 mg L-1; and Ag-bem[registered trademark] 34.95 mg L-1. The variables of water quality were unchanged. The fish showed an increase in the opercular beating after exposure; 4 and 24 hours, loss of gasping ability; 48 hours, slow opercular beating; and 72 and 96 hours later, recovery. The surfactants Energic[registered trademark], Agral[registered trademark], Gotafix[registered trademark], Aterbane[registered trademark] BR and Fixade[registered trademark] can be classified as moderately toxics, and Ag-Bem[registered trademark] as slightly toxic for H. eques; this organism shows similar intoxication signs for all surfactants.

On the interaction of small molecules with hemoproteins: Sperm whale myoglobin

The spin label TEMPO does not show a binding to myoglobin molecule in solution. This is probably due to the fact that this protein does not have a hydrophobic pocket large enough to accommodate the TEMPO molecule. In the crystal the spin label is bound and two kinds of spectra are observed: one isotropic and the other anisotropic. The anisotropic site is probably an intermolecular one. The correlation time for the label in the crystal is very sensitive to temperature showing a transition near 30 °C. This change can be explained as a result of the conformational change observed for myoglobin near this temperature: the motion of the spin label becomes more restricted below this temperature. Change in hydration is the probable cause of this structural change. The changes in the EPR spectra of the anisotropic label suggest that it is bound near the first layers of protein in the crystal. © 1985 Societá Italiana di Fisica.

Interaction between Li+ and C60 molecules

MNDO calculations with complete geometry optimization were used to calculate the interaction between Li+ and C60, C- 60 and C2- 60 molecules. In order to determine the more stable configuration, Li+ was approximated to the C60 molecule or to their reduced forms from 10 Å up to the geometric center of the molecule. From the simulations we determine that Li+ remains close to the surface at 5 Å from the geometric center of the C60 molecules. © 1995.

Interaction of the nonionic surfactant C12E8 with high molar mass poly(ethylene oxide) studied by dynamic light scattering and fluorescence quenching methods

Dynamic light scattering has been used to investigate ternary aqueous solutions of n-dodecyl octaoxyethylene glycol monoetber (C12E8) with high molar mass poly(ethylene oxide) (PEO). The measurements were made at 20 °C, always below the cloud point temperature (Tc) of the mixed solutions. The relaxation time distributions are bimodal at higher PEO and surfactant concentrations, owing to the preacute of free surfactant micelles, which coexist with the slower component, representing the polymer coil/micellar cluster comptex. As the surfactant concentration is increased, the apparent hydrodynamic radius (RH) of the coil becomes progressively larger. It is suggested that the complex structure consists of clusters of micelles sited within the polymer coil, as previously concluded for the PEO-C12E8-water system. However. C12E8 interacts less strongly than C12E8 with PEO; at low concentrations of surfactant the complex does not contribute significantly to the total scattered intensity. The perturbation of the PEO coil radius with C12E8 is also smaller than that in the C12E8 system. The addition of PEO strongly decreases the clouding temperature of the system, as previously observed for C12E8/PEO mixtures in solution Addition of PEO up to 0.2% to C12E8 (10 wt %) solutions doss not alter the aggregation number (Nagg) of the micelles probably because the surfactant monomers are equally partitioned as bound and unbound micelles. The critical micelle concentration (cmc), obtained from the I1/I3 ratio (a measure of the dependence of the vibronic band intensities on the pyrene probe environment), does not change when PEO is added, suggesting that for neutral polymer/surfactant systems the trends in Nagg and the cmc do not unambiguously reflect the strength of interaction.

Scaling predictions for radii of weakly bound triatomic molecules

The mean-square radii of the triatomic molecules 4He 3, 4He 2- 6Li, 4He 2- 7Li, and 4He 2- 23Na were calculated using a renormalized three-body model with a pairwise Dirac-δ interaction, having as physical inputs only the values of the binding energies of the diatomic and triatomic molecules. Molecular three-body systems with bound subsystems were considered. The resultant data were analyzed in detail.

Different doses of exogenous surfactant for treatment of meconium aspiration syndrome in newborn rabbits.

OBJECTIVE: To evaluate the effects of 2 different doses of exogenous surfactant on pulmonary mechanics and on the regularity of pulmonary parenchyma inflation in newborn rabbits. METHOD: Newborn rabbits were submitted to tracheostomy and randomized into 4 study groups: the Control group did not receive any material inside the trachea; the MEC group was instilled with meconium, without surfactant treatment; the S100 and S200 groups were instilled with meconium and were treated with 100 and 200 mg/kg of exogenous surfactant (produced by Instituto Butantan) respectively. Animals from the 4 groups were mechanically ventilated during a 25-minute period. Dynamic compliance, ventilatory pressure, tidal volume, and maximum lung volume (P-V curve) were evaluated. Histological analysis was conducted using the mean linear intercept (Lm), and the lung tissue distortion index (SDI) was derived from the standard deviation of the means of the Lm. One-way analysis of variance was used with a = 0.05. RESULTS: After 25 minutes of ventilation, dynamic compliance (mL/cm H2O.kg) was 0.87 +/- 0.07 (Control); 0.49 +/- 0.04 (MEC*); 0.67 +/- 0.06 (S100); and 0.67 +/- 0.08 (S200), and ventilatory pressure (cm H2O) was 9.0 +/- 0.9 (Control); 16.5 +/- 1.7 (MEC*); 12.4 +/- 1.1 (S100); and 12.1 +/- 1.5 (S200). Both treated groups had lower Lm values and more homogeneity in the lung parenchyma compared to the MEC group: SDI = 7.5 +/- 1.9 (Control); 11.3 +/- 2.5 (MEC*), 5.8 +/- 1.9 (S100); and 6.7 +/- 1.7 (S200) (*P < 0.05 versus all the other groups). CONCLUSIONS: Animals treated with surfactant showed significant improvement in pulmonary mechanics and more regularity of the lung parenchyma in comparison to untreated animals. There was no difference in results after treatment with either of the doses used.

Expression of the nonclassical HLA-G and HLA-E molecules in laryngeal lesions as biomarkers of tumor invasiveness

Introduction: HLA-G and HLA-E are two nonclassical class I molecules, which have been well recognized as modulators of innate and adaptive immune responses, and the expression of these molecules in virus infected cells has been associated with subversion of the immune response. Objective: In this study we performed a cross-sectional study, systematically comparing the expression of HLA-G and HLA-E in benign, premalignant and malignant laryngeal lesions, correlating with demographic and clinical variables and with the presence of high-risk and low-risk HPV types. Materials and methods: Laryngeal lesions were collected from 109 patients and stratified into 27 laryngeal papillomas, 17 dysplasias, 10 in situ laryngeal carcinomas, 27 laryngeal carcinomas without metastases, 28 laryngeal carcinomas with metastasis along with their respective draining cervical lymph nodes, and 10 normal larynx specimens. The expression of HLA-G and HLA-E molecules was determined by immunohistochemistry. HPV DNA detection and typing was performed using generic and specific primers. Results: HLA nonclassical molecules showed a distinct distribution pattern, according to the larynx lesion grade. HLA-G expression increased in benign and premalignant lesions, and gradually decreased in invasive carcinomas and in respective draining cervical lymph nodes. Conversely, HLA-E expression increased as far as lesion grade increased, including increased molecule expression in the draining lymph nodes of malignant lesions. Only 17 (15.6%) patients were HPV DNA positive. Conclusions: Overexpression of HLA-E and underexpression of HLAG appear to be good markers for malignant larynx lesion.

Cooperative RNA Polymerase Molecules Behavior on a Stochastic Sequence-Dependent Model for Transcription Elongation

The transcription process is crucial to life and the enzyme RNA polymerase (RNAP) is the major component of the transcription machinery. The development of single-molecule techniques, such as magnetic and optical tweezers, atomic-force microscopy and single-molecule fluorescence, increased our understanding of the transcription process and complements traditional biochemical studies. Based on these studies, theoretical models have been proposed to explain and predict the kinetics of the RNAP during the polymerization, highlighting the results achieved by models based on the thermodynamic stability of the transcription elongation complex. However, experiments showed that if more than one RNAP initiates from the same promoter, the transcription behavior slightly changes and new phenomenona are observed. We proposed and implemented a theoretical model that considers collisions between RNAPs and predicts their cooperative behavior during multi-round transcription generalizing the Bai et al. stochastic sequence-dependent model. In our approach, collisions between elongating enzymes modify their transcription rate values. We performed the simulations in Mathematica® and compared the results of the single and the multiple-molecule transcription with experimental results and other theoretical models. Our multi-round approach can recover several expected behaviors, showing that the transcription process for the studied sequences can be accelerated up to 48% when collisions are allowed: the dwell times on pause sites are reduced as well as the distance that the RNAPs backtracked from backtracking sites. © 2013 Costa et al.

Role of adhesion molecules and proliferation hyperplasic, pre neoplastic and neoplastic lesions in canine prostate

E-cadherin and beta-catenin are component of adherens junctions in epithelial cells. Loss of these proteins have been associated with progression of prostatic diseases. We performed immunohistochemistry for E-cadherin, beta-catenin and Ki-67 on canine prostatic lesions. We analyzed the expression of these antibodies in benign prostatic hyperplasia (BPH, n = 22), in pre neoplastic lesions Prostatic Intra-epithelial Neoplasia (PIN), n = 3 and Prostatic Inflammatory Atrophy (PIA), n = 7 and prostate carcinoma (PC, n = 10). In this study, a membranous expression of E-cadherin and beta-catenin and nuclear expression of Ki-67 antigen were demonstrated. The proliferative index was statistically different between carcinomas and BPH and carcinomas and pre-neoplastic lesions. Like in men, the reduction of E-cadherin and increase of Ki-67 expression in neoplastic lesions in dog prostate may be related to the carcinogenic process in this gland. © 2013 Asian Network for Scientific Information.

The effects of water molecules on the electronic and structural properties of peptide nanotubes

The self-assembly of short amino acid chains appears to be one of the most promising strategies for the fabrication of nanostructures. Their solubility in water and the possibility of chemical modification by targeting the amino or carboxyl terminus give peptide-based nanostructures several advantages over carbon nanotube nanostructures. However, because these systems are synthesized in aqueous solution, a deeper understanding is needed on the effects of water especially with respect to the electronic, structural and transport properties. In this work, the electronic properties of l-diphenylalanine nanotubes (FF-NTs) have been studied using the Self-Consistent Charge Density-Functional-based Tight-Binding method augmented with dispersion interaction. The presence of water molecules in the central hydrophilic channel and their interaction with the nanostructures are addressed. We demonstrate that the presence of water leads to significant changes in the electronic properties of these systems decreasing the band gap which can lead to an increase in the hopping probability and the conductivity. © the Owner Societies 2013.

No evidence for association of the CD40, CD40L and BLYS polymorphisms, B-cell co-stimulatory molecules, with Brazilian endemic Plasmodium vivax malaria

Background: Plasmodium vivax is the most prevalent malaria species in Brazil. The parasite-host coevolutionary process can be viewed as an 'arms race', in which adaptive genetic changes in one are eventually matched by alterations in the other. Methods: Following the candidate gene approach we analyzed the CD40, CD40L and BLYS genes that participate in B-cell co-stimulation, for associations with P. vivax malaria. The study sample included 97 patients and 103 controls. We extracted DNA using the extraction and purification commercial kit and identified the following SNPs: 21C.T in the CD40 gene, 2726T.C in the CD40L gene and the 2871C.T in the BLyS gene using PCR-RFLP. We analyzed the genotype and allele frequencies by direct counting. We also compared the observed with the expected genotype frequencies using the Hardy-Weinberg equilibrium. Results: The allele and genotype frequencies for these SNPs did not differ statistically between patient and control groups. Gene-gene interactions were not observed between the CD40 and BLYS and between the CD40L and BLYS genes. Overall, the genes were in Hardy-Weinberg equilibrium. Significant differences were not observed among the frequencies of antibody responses against P. vivax sporozoite and erythrocytic antigens and the CD40 and BLYS genotypes. Conclusions: The results of this study show that, although the investigated CD40, CD40L and BLYS alleles differ functionally, this variation does not alter the functionality of the molecules in a way that would interfere in susceptibility to the disease. The variants of these genes may influence the clinical course rather than simply increase or decrease susceptibility. © Royal Society of Tropical Medicine and Hygiene 2013. All rights reserved.

A novel function for CUGBP2 in controlling the pro-inflammatory stimulus in H9c2 cells: Subcellular trafficking of messenger molecules

Accumulating evidence demonstrates that chronic inflammation plays an important role in heart hypertrophy and cardiac diseases. However, the fine-tuning of cellular and molecular mechanisms that connect inflammatory process and cardiac diseases is still under investigation. Many reports have demonstrated that the overexpression of the cyclooxygenase-2 (COX-2), a key enzyme in the conversion of arachidonic acid to prostaglandins and other prostanoids, is correlated with inflammatory processes. Increased level of prostaglandin E2 was also found in animal model of left ventricle of hypertrophy. Based on previous observations that demonstrated a regulatory loop between COX-2 and the RNA-binding protein CUGBP2, we studied cellular and molecular mechanisms of a pro-inflammatory stimulus in a cardiac cell to verify if the above two molecules could be correlated with the inflammatory process in the heart. A cellular model of investigation was established and H9c2 was used.We also demonstrated a regulatory connection between COX-2 and CUGBP2 in the cardiac cells. Based on a set of different assays including gene silencing and fluorescence microscopy, we describe a novel function for the RNA-binding protein CUGBP2 in controlling the pro-inflammatory stimulus: subcellular trafficking of messenger molecules to specific cytoplasmic stress granules to maintain homeostasis. © 2013 International Federation for Cell Biology.

Sustainable production of biologically active molecules of marine based origin

The marine environment offers both economic and scientific potential which are relatively untapped from a biotechnological point of view. These environments whilst harsh are ironically fragile and dependent on a harmonious life form balance. Exploitation of natural resources by exhaustive wild harvesting has obvious negative environmental consequences. From a European industry perspective marine organisms are a largely underutilised resource. This is not due to lack of interest but due to a lack of choice the industry faces for cost competitive, sustainable and environmentally conscientious product alternatives. Knowledge of the biotechnological potential of marine organisms together with the development of sustainable systems for their cultivation, processing and utilisation are essential. In 2010, the European Commission recognised this need and funded a collaborative RTD/SME project under the Framework 7-Knowledge Based Bio-Economy (KBBE) Theme 2 Programme 'Sustainable culture of marine microorganisms, algae and/or invertebrates for high value added products'. The scope of that project entitled 'Sustainable Production of Biologically Active Molecules of Marine Based Origin' (BAMMBO) is outlined. Although the Union is a global leader in many technologies, it faces increasing competition from traditional rivals and emerging economies alike and must therefore improve its innovation performance. For this reason innovation is placed at the heart of a European Horizon 2020 Strategy wherein the challenge is to connect economic performance to eco performance. This article provides a synopsis of the research activities of the BAMMBO project as they fit within the wider scope of sustainable environmentally conscientious marine resource exploitation for high-value biomolecules. © 2013 Elsevier B.V.

Síntese de nanopartículas de sílica mesoporosa e aplicações como biomaterial

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