Structural modeling and mutational analysis of yeast eukaryotic translation initiation factor 5A reveal new critical residues and reinforce its involvement in protein synthesis

Eukaryotic translation initiation factor 5A (eIF5A) is a protein that is highly conserved and essential for cell viability. This factor is the only protein known to contain the unique and essential amino acid residue hypusine. This work focused on the structural and functional characterization of Saccharomyces cerevisiae eIF5A. The tertiary structure of yeast eIF5A was modeled based on the structure of its Leishmania mexicana homologue and this model was used to predict the structural localization of new site-directed and randomly generated mutations. Most of the 40 new mutants exhibited phenotypes that resulted from eIF-5A protein-folding defects. Our data provided evidence that the C-terminal alpha-helix present in yeast eIF5A is an essential structural element, whereas the eIF5A N-terminal 10 amino acid extension not present in archaeal eIF5A homologs, is not. Moreover, the mutants containing substitutions at or in the vicinity of the hypusine modification site displayed nonviable or temperature-sensitive phenotypes and were defective in hypusine modification. Interestingly, two of the temperature-sensitive strains produced stable mutant eIF5A proteins - eIF5A(K56A) and eIF5A(Q22H,L93F)- and showed defects in protein synthesis at the restrictive temperature. Our data revealed important structural features of eIF5A that are required for its vital role in cell viability and underscored an essential function of eIF5A in the translation step of gene expression.

Using of model updating considering damped frequency response function

The search for better performance in the structural systems has been taken to more refined models, involving the analysis of a growing number of details, which should be correctly formulated aiming at defining a representative model of the real system. Representative models demand a great detailing of the project and search for new techniques of evaluation and analysis. Model updating is one of this technologies, it can be used to improve the predictive capabilities of computer-based models. This paper presents a FRF-based finite element model updating procedure whose the updating variables are physical parameters of the model. It includes the damping effects in the updating procedure assuming proportional and none proportional damping mechanism. The updating parameters are defined at an element level or macro regions of the model. So, the parameters are adjusted locally, facilitating the physical interpretation of the adjusting of the model. Different tests for simulated and experimental data are discussed aiming at defining the characteristics and potentialities of the methodology.

Association Between Insulin Resistance, Glucose Intolerance, and Hypertension in Pregnancy

There is an association between insulin resistance, glucose intolerance, and essential hypertension, but the relation between insulin resistance, glucose intolerance, and hypertension diagnosed during pregnancy is not well understood. Transient hypertension of pregnancy, the new-onset nonproteinuric hypertension of late pregnancy, is associated with a high risk of later essential hypertension and glucose intolerance; thus, these conditions may have a similar pathophysiology. To assess the association between insulin resistance, glucose intolerance, essential hypertension, and subsequent development of proteinuric and nonproteinuric hypertension in pregnancy in women without underlying essential hypertension, we performed a prospective study comparing glucose (fasting, I and 2 hours postglucose load), insulin, glycosylated hemoglobin (HbA1c), high-density lipoprotein cholesterol (HDL-C), and triglycerides levels on routine screening for gestational diabetes mellitus. Women who developed hypertension in pregnancy (n = 37) had higher glycemic levels (fasting, 1 and 2 hours postglucose load) on a 100-gram oral glucose loading test, although only the fasting values showed a statistical significance (p < 0.05), and a significantly higher frequency of abnormal glucose loading tests, two hours after glucose load (>= 140 mg/dL) (p < 0.05) than women who remained normotensive (n = 180). Glucose intolerance was common in women who developed both subtypes of hypertension, particularly preeclampsia. Women who developed hypertension had greater prepregnancy body mass index (p < 0.0001), higher frequency and intensity of acanthosis nigricans (p < 0.0001), and higher baseline systolic and diastolic blood pressures (p <= 0.0001 for both), although all subjects were normotensive at baseline by study design; they also presented lower levels of HDL-C (p < 0.05). However, after adjustment for these and other potential confounders, an abnormal glucose loading test remained a significant predictor of development of hypertension (p < 0.05) and, specifically, preeclampsia (p < 0.01). There was a trend toward higher insulin and homeostasis model assessment-insulin resistance (HOMA-IR) levels in women developing any type of hypertension. When comparing women that remained normotensive to term with those with transient hypertension and preeclampsia, the preeclamptic women were born with lower weight (p < 0.05) and shorter length (p < 0.005); at screening they were older (p < 0.005), showed higher frequency and intensity of acanthosis nigricans (p < 0.0001), had higher prepregnancy BMI (p < 0.0005), as well as higher baseline systolic and diastolic blood pressures (p <= 0.0001 for both). They also showed higher HOMA-IR levels that did not show a statistical significance. When glucose tolerance status was taken in account, an association was found between increasing indexes of hypertension (p < 0.05) and of HOMA-IR (p < 0.05) with the worsening of glucose tolerance. These results suggest that insulin resistance and relative glucose intolerance are associated with an increased risk of new-onset hypertension in pregnancy, particularly preeclampsia, and support the hypothesis that insulin resistance may play a role in the pathogenesis of this disorder.

Genetic and environmental factors that affect the best time of Thoroughbred horses in Brazil

On the basis of information provided by the Brazilian Association of Race Horse Breeders, we analysed the racing performance of 947 Thoroughbred horses in races held from 1985 to 1992. The performance was evaluated using the best, time of the animals. The variance component was obtained by the derivative-free restricted maximum likelihood method, and the model used contained fixed effects of the racing month and year, sex, race track, track condition, animal age, number of competitors in race, and distance, and the random animal effect. The low heritability estimate obtained (0.12) indicates that selection based on animal phenotypic value must induce small genetic changes in this trail.

Initiating structural studies of Lys49-PLA2 homologues complexed with an anionic detergent, a fatty acid and a natural lipid

Lys49-Phospholipase A(2) (Lys49-PLA(2) - EC 3.1.1.4) homologues damage membranes by a Ca2+-independent mechanism which does not involve catalytic activity. Both MjTX-II from Bothrops moojeni and BthTX-I from Bothrops jararacussu are dimeric in solution and in the crystalline states, and a model for the Ca2+-independent membrane damaging mechanism has been suggested in which flexibility at the dimer interface region pert-nits quaternary structural transitions between open and closed membrane bound dimer conformations which results in the perturbation of membrane phospholipids and disruption of the bilayer structure [1]. With the aim of gaining insights into the structural determinants involved in protein/lipid association, we report here the crystallization and preliminary X-ray analysis of the (i) MjTX-II/SDS complex at a resolution of 2.78Angstrom, (ii) MjTX-II/STE complex at a resolution of 1.8 Angstrom and (W) BthTX-I/DMPC complex at 2.72Angstrom. These complexes were crystallized by the hanging drop vapour-diffusion technique in (i) HEPES buffer (pH 7.5) 1.8M ammonium sulfate with 2% (w/v) polyethyleneglycol 400, in (ii) 0.6-0.8 M sodium citrate as the precipitant (pH 6.0-6.5) and in (iii) sodium citrate buffer (pH 5.8) and PEG 4000 and 20% isopropanol, respectively. Single crystals of these complexes have been obtained and X-ray diffraction data have been collected at room temperature using a R-AXIS IV imaging plate system and graphite monochromated Cu Kalpha X-ray radiation generated by a Rigaku RU300 rotating anode generator for (i) and (W) and using using a Synchrotron Radiation Source (Laboratorio Nacional de Luz Sincrotron, LNLS, Campinas, Brazil) for (ii).

Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol)/Sodium Polyacrylate/Salts

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

Search for physics beyond the standard model using multilepton signatures in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for B-s(0) -> mu(+)mu(-) and B-0 -> mu(+)mu(-) Decays in pp Collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for dark matter and large extra dimensions in monojet events in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Kinetic model of poly(3-hydroxybutyrate) thermal degradation from experimental non-isothermal data

The non-isothermal data given by TG curves for poly(3-hydroxybutyrate) (PHB) were studied in order to obtain a consistent kinetic model that better represents the PHB thermal decomposition. Thus, data obtained from the dynamic TG curves were suitably managed in order to obtain the Arrhenius kinetic parameter E according to the isoconversional F-W-O method. Once the E parameters is found, a suitable logA and kinetic model (f(alpha)) could be calculated. Hence, the kinetic triplet (E +/- SD, logA +/- SD and f(alpha)) obtained for the thermal decomposition of PHB under non-isothermal conditions was E=152 +/- 4 kJ mol(-1), logA=14.1 +/- 0.2 s(-1) for the kinetic model, and the autocatalytic model function was: f(alpha)=alpha(m)(1-alpha)(n)=alpha(0.42)(1-alpha)(0.56).

Experimental ischemia and reperfusion in equine small colon

Sob anestesia geral, com constante controle sobre a pressão arterial e a saturação de oxigênio da hemoglobina arterial, realizou-se celiotomia em 12 eqüinos. No cólon menor exposto foram demarcados três segmentos de 25cm, separados entre si por igual distância. Dois desses segmentos foram submetidos à isquemia arteriovenosa completa por 90 (grupo A) ou 180 minutos (grupo B). O terceiro segmento foi o grupo-controle. Amostras para histopatologia foram colhidas ao final dos períodos de isquemia e após 90 e 180 minutos de reperfusão no grupo A e após 90 minutos de reperfusão no grupo B. No controle, colheram-se amostras no início e final do procedimento. Avaliaram-se as lesões produzidas na mucosa e na submucosa pelos métodos semiquantitativos-escores para desprendimento de epitélio, edema, hemorragia e infiltrado de neutrófilos, e pelos quantitativos-porcentagem de perda de mucosa (PM) e razão cripta:interstício (C:I). As lesões isquêmicas foram mais intensas no grupo B do que no A para PM, C:I, desprendimento de epitélio e edema de mucosa. As amostras obtidas após a reperfusão revelaram que houve agravamento na PM, C:I, desprendimento de epitélio e edema de submucosa em ambos os grupos. Concluiu-se que a reperfusão agravou as lesões isquêmicas no cólon menor e que o modelo proposto é viável para produção dessas lesões.

Terrane transfer during the Grenville orogeny: tracing the Amazonian ancestry of southern Appalachian basement through Pb and Nd isotopes

Whole rock Pb isotope data can be used to determine the provenance of different blocks within the Rodinia supercontinent, providing a test for paleogeographic reconstructions. Calculated isotopic values for the source region of the Grenville-deformed SW Amazon craton (Rondonia, Brazil), anchored by published U-Pb zircon ages, are compared to those from the Grenville belt of North America and Grenvillian basement inliers in the southern Appalachians. Both the SW Amazon craton and the allochthonous Blue Ridge/Mars Hill terrane are defined by a similar Pb isotopic signature, indicating derivation from an ancient source region with an elevated U/Pb ratio. In contrast, the Grenville Province of Laurentia (extending from Labrador to the Llano Uplift of Texas) is characterized by a source region with a distinctly lower, time-integrated U/Pb ratio. Published U-Pb zircon ages (ca. 1.8 Ga) and Nd model ages (1.4-2.2 Ga) for the Blue Ridge/Mars Hill terrane also suggest an ancient provenance very different from the rest of the adjacent Grenville belt, which is dominated by juvenile 1.3-1.5 Ga rocks. The presence of mature continental material in rocks older than 1.15 Ga in the Blue Ridge/ Mars Hill terrane is consistent with characteristics of basement rocks from the SW Amazon craton. High-grade metamorphism of the Blue Ridge/Mars Hill basement resulted in purging of U, consistent with observations of the rest of the North American Grenville province. In contrast, the Grenvillian metamorphic history of the Amazon appears to have been much more heterogeneous, with both U enrichment and U depletion recorded locally. We propose that the Blue Ridge/ Mars Hill portion of the Appalachian basement is of Amazonian provenance and was transferred to Laurentia during Grenvillian orogenesis after similar to1.15 Ga. The presence of these Amazonian rocks in southeastern Laurentia records the northward passage of the Amazon craton along the Laurentian margin, following the original collision with southernmost Laurentia at ca. 1.2 Ga. (C) 2004 Elsevier B.V. All rights reserved.

Staphylococcus aureus: Resistance patterns to antimicrobials and Penicillinase among strains isolated from apparently healthy lactating cows

Ninety-two strains of Staphylococcus aureus isolated from the nasal fossa and udder skin of apparently healthy lactating cows were analyzed for resistance to antibiotics and production of penicillinase.The results showed a greater frequency of resistance patterns to penicillin and ampicillin.All strains were sensitive to oxacyllin and gentamicin.The most frequent Barber and Burston model was SSSS (60.90%), followed by RSSS (18.50%).With respect to the production of penicillinase although the Lucas method indicated a larger number of positive samples, we suggest the use of the Haight and Finland method due to a greater consistency of data obtained with it.

Product development process: Using real options for assessments and to support the decision-making at decision gates

Enterprises need continuous product development activities to remain competitive in the marketplace. Their product development process (PDP) must manage stakeholders' needs - technical, financial, legal, and environmental aspects, customer requirements, Corporate strategy, etc. -, being a multidisciplinary and strategic issue. An approach to use real option to support the decision-making process at PDP phases in taken. The real option valuation method is often presented as an alternative to the conventional net present value (NPV) approach. It is based on the same principals of financial options: the right to buy or sell financial values (mostly stocks) at a predetermined price, with no obligation to do so. In PDP, a multi-period approach that takes into account the flexibility of, for instance, being able to postpone prototyping and design decisions, waiting for more information about technologies, customer acceptance, funding, etc. In the present article, the state of the art of real options theory is prospected and a model to use the real options in PDP is proposed, so that financial aspects can be properly considered at each project phase of the product development. Conclusion is that such model can provide more robustness to the decisions processes within PDP.

On the equivalence of the mechanisms governing switching and hysteresis phenomena

The nucleation and growth model, which is usually applied to switching phenomena, is adapted for explaining surface potential measurements on the P(VDF-TrFE) (polyvinylidene fluoride-trifluoroethylene) copolymer obtained in a constant current corona triode. It is shown that the growth is one-dimensional and that the nucleation rate is unimportant, probably because surface potential measurements take much longer than the switching ones. The surface potential data can therefore be accounted for by a growth model in which the velocity of growth varies exponentially with the electric field. Since hysteresis loops can be obtained from surface potential measurements, it is suggested that similar mechanisms can be used when treating switching and hysteresis phenomena, provided that account is taken of the difference in the time scale of the measurements.