Molecular modeling of the human eukaryotic translation initiation factor 5A (eIF5A) based on spectroscopic and computational analyses

The eukaryotic translation initiation factor 5A (eIF5A) is a protein ubiquitously present in archaea and eukarya, which undergoes a unique two-step post-translational modification called hypusination. Several studies have shown that hypusination is essential for a variety of functional roles for eIF5A, including cell proliferation and synthesis of proteins involved in cell cycle control. Up to now neither a totally selective inhibitor of hypusination nor an inhibitor capable of directly binding to eIF5A has been reported in the literature. The discovery of such an inhibitor might be achieved by computer-aided drug design based on the 3D structure of the human eIF5A. In this study, we present a molecular model for the human eIF5A protein based on the crystal structure of the eIF5A from Leishmania brasiliensis, and compare the modeled conformation of the loop bearing the hypusination site with circular dichroism data obtained with a synthetic peptide of this loop. Furthermore, analysis of amino acid variability between different human eIF5A isoforms revealed peculiar structural characteristics that are of functional relevance.     

Induction of Autophagy by Second-Fermentation Yeasts during Elaboration of Sparkling Wines

Autophagy is a transport system mediated by vesicles, ubiquitous in eukaryotic cells, by which bulk cytoplasm is targeted to a lysosome or vacuole for degradation. In the yeast Saccharomyces cerevisiae, autophagy is triggered by nutritional stress conditions (e.g., carbon- or nitrogen-depleted medium). In this study we showed that there is induction of autophagy in second-fermentation yeasts during sparkling wine making. Two methods were employed to detect autophagy: a biochemical approach based on depletion of the protein acetaldehyde dehydrogenase Ald6p and a morphological strategy consisting of visualization of autophagic bodies and autophagosomes, which are intermediate vesicles in the autophagic process, by transmission electron microscopy. This study provides the first demonstration of autophagy in second-fermentation yeasts under enological conditions. The correlation between autophagy and yeast autolysis during sparkling wine production is discussed, and genetic engineering of autophagy-related genes in order to accelerate the aging steps in wine making is proposed.     

Genetic and molecular characterization of the I locus of Phaseolus vulgaris

The I locus of the common bean, Phaseolus vulgaris, controls the development of four different phenotypes in response to inoculation with Bean common mosaic virus, Bean common mosaic necrosis virus, several other related potyviruses, and one comovirus. We have generated a high-resolution linkage map around this locus and have aligned it with a physical map constructed with BAC clones. These clones were obtained from a library of the cultivar "Sprite," which carries the dominant allele at the I locus. We have identified a large cluster of TIR-NBS-LRR sequences associated within this locus, which extends over a distance >425 kb. Bean cultivars from the Andean or Mesoamerican gene pool that contain the dominant allele share the same haplotypes as revealed by gel blot hybridizations with a TIR probe. In contrast, beans with a recessive allele display simpler and variable haplotypes. A survey of wild accessions from Argentina to Mexico showed that this multigene family has expanded significantly during evolution and domestication. RNA gel blot analysis indicated that the TIR family of genes plays a role in the response to inoculations with BCMV or BCMNV.     

Molecular systematics of the Hyaenidae: relationships of a relictual lineage resolved by a molecular supermatrix

The four extant species of hyenas (Hyaenidae; Carnivora) form a morphologically and ecologically heterogeneous group of feliform carnivorans that are remnants of a formerly diverse group of mammalian predators. They include the aardwolf (Proteles cristatus), a termite-feeding specialist, and three species with a craniodental morphology adapted to cracking the bones of prey and/or carcasses, the spotted hyena (Crocuta crocuta), brown hyena (Parahyaena brunnea), and striped hyena (Hyaena hyaena). Hyenas have been the subject of a number of systematic studies during the last two centuries, due in large part to the extensive fossil record of the group, with nearly 70 described fossil species. Morphological studies incorporating both fossil and living taxa have yielded different conclusions regarding the evolutionary relationships among living hyenas. We used a molecular supermatrix comprised of seven nuclear gene segments and the complete mitochondrial cytochrome b gene to evaluate phylogenetic relationships among the four extant hyaenid species. We also obtained sequence data from representative species of all the main families of the Feliformia (Felidae, Herpestidae, and Viverridae) to estimate the sister group of the Hyaenidae. Maximum parsimony and maximum likelihood analyses of the supermatrix recovered identical topologies. Furthermore, Bayesian phylogenetic analyses of the supermatrix, with among-site rate variation among data partitions parameterized in three different ways, also yielded the same topology. For each phylogeny reconstruction method, all but two nodes received 100% bootstrap or 1.00 posterior probability nodal support. Within the monophyletic Hyaenidae, Parahyaena and Hyaena were joined together, with Crocuta as the sister to this clade, and Proteles forming the most basal lineage. A clade containing two species of mongoose (core Herpestidae) plus Cryptoprocta ferox (currently classified in Viverridae) was resolved as the sister group of Hyaenidae. The pattern of relationships among the three bone-cracking hyaenids (Crocuta, Hyaena, and Parahyaena) is incongruent with recent cladistic assessments based on morphology and suggests the need to reevaluate some of the morphological characters that have been traditionally used to evaluate relationships among hyenas. Divergence time estimates based on a Bayesian relaxed molecular clock indicates that hyaenids diverged from their feliform sister group 29.2 MYA, in the Middle Oligocene. Molecular clock estimates also suggest that the origin of the aardwolf is much more recent (10.6 MYA) than that implied by a cladistic analysis of morphology ( approximately 20 MYA) and suggests that the aardwolf is possibly derived from a bone and meat eating lineage of hyaenids that were present in the Late Miocene. [Hyaenidae; phylogeny; cytochrome b; nuclear gene segments; Proteles; Crocuta; Hyaena; Parahyaena.].     

Overexpression of inducible nitric oxide synthase and cyclooxygenase-2 in rat zinc-deficient lung: Involvement of a NF-kappaB dependent pathway.

Reactive oxygen and nitrogen species have been implicated in the pathogenesis of pulmonary diseases. The goal of this study was to measure the response of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 enzymes (COX-2) in lung with moderate zinc deficiency. Adult male Wistar rats were divided into two groups receiving (1) a zinc-deficient diet (ZD) or (2) a zinc-adequate control diet. After 2 months of treatment, the zinc-deficient group showed a significant pulmonary edema. This was associated to a reduction of protein thiols and to a significant increase of metallothionein and glutathione disulfide levels. In addition, a higher serum and lung NO production in ZD group was positively related to the higher activity and expression of iNOS and COX-2 found in lungs. Western blot analysis revealed increased IkappaBalpha degradation, an indicator of NF-kappaB activation in ZD lungs. Anatomopathologic analysis of ZD lungs showed an increase of connective tissue fibers with an influx of polymorphonuclear cells. These cells and type II cells from the alveoli showed specific immunohistochemical signals for iNOS. The conclusion is that, during the development of zinc-deficiency, iNOS activity increases in lung and contributes to lung injury. Zinc deficiency implications must be taken into account to design therapies and public health interventions involving targeted zinc supplementation for high-risk subjects or certain diseases, such as asthma.     

Arachidonic acid induces an increase of β-1,4-galactosyltransferase I expression in MDA-MB-231 breast cancer cells

Arachidonic acid (AA) is a common dietary n‐6 cis polyunsaturated fatty acid that under physiological conditions is present in an esterified form in cell membrane phospholipids, and it might be present in the extracellular microenvironment. AA and its metabolites are implicated in FAK activation and cell migration in MDA‐MB‐231 breast cancer cells, and an epithelial‐to‐mesenchymal‐like transition process in mammary non‐tumorigenic epithelial cells MCF10A. During malignant transformation is present an altered expression of glycosiltransferases, which promote changes on the glycosilation of cell‐surface proteins. The β‐1,4‐galactosyltransferase I (GalT I) is an enzyme that participates in a variety of biological functions including cell growth, migration, and spreading. However, the participation of AA in the regulation of GalT I expression and the role of this enzyme in the cell adhesion process in breast cancer cells remains to be investigated. In the present study, we demonstrate that AA induces an increase of GalT I expression through a PLA2α, Src, ERK1/2, and LOXs activities‐dependent pathway in MDA‐MB‐231 breast cancer cells. Moreover, MDA‐MB‐231 cells adhere to laminin via GalT I expression and pretreatment of cells with AA induces an increase of cell adhesion to laminin. In conclusion, our findings demonstrate, for the first time, that AA promotes an increase of GalT I expression through an AA metabolism, Src and ERK1/2 activities‐dependent pathway, and that GalT I plays a pivotal role in cell adhesion to laminin in MDA‐MB‐231 breast cancer cells. J. Cell. Biochem. 113: 3330–3341, 2012. © 2012 Wiley Periodicals, Inc.     

Effect of long-term water immersion on the fracture toughness of denture base and reline resins

doi: 10.1111/j.1741‐2358.2011.00573.x
Effect of long‐term water immersion on the fracture toughness of denture base and reline resins purpose: This study evaluated the fracture toughness (FT) of one denture base (Lucitone 550 – L) and four hard reline resins [Ufi Gel Hard (UH), Tokuyama Rebase II (TR), New Truliner (NT) and Kooliner (K)], and the effect of long‐term water storage on this property. Materials and methods: Forty specimens (40 × 8 × 4 mm) of each material were made, and FT was assessed after polymerisation (control of reliners), after 48 ± 2 h in water at 37°C (control of denture base resin) and after storage in water at 37°C for 7, 90 or 180 days (all materials). Data (MPa.m^1/2) were analysed by two‐way anova and Games–Howell test (p = 0.05). Results: Resin L exhibited the highest FT mean values. After 180 days of storage, FT mean values of L (3.37), UH (1.53) and K (1.20) were higher than those of the other periods. FT mean values of NT decreased from control (1.63) to 7 days (1.30) and then remained constant. FT mean values of TR (1.13) were similar in all periods of analysis. Conclusion: The denture base resin L showed higher FT mean values than the reline resins. Long‐term water storage increased the FT of L, UH and K, reduced the FT of NT and did not influence the FT of TR.     

Surface roughness of denture base and reline materials after disinfection by immersion in chlorhexidine or microwave irradiation

doi: 10.1111/j.1741‐2358.2011.00484.x
Surface roughness of denture base and reline materials after disinfection by immersion in chlorhexidine or microwave irradiation Background: This study evaluated the effect of disinfection by immersion and microwave irradiation on the roughness of one denture base resin (Lucitone‐L) and five relining materials, three hard (Tokuyama Rebase II‐TR, New Truliner‐NT, Ufigel Hard‐UH) and two resilient (Trusoft‐T, Sofreliner‐S). Methods: Fifty specimens were made and divided into groups: CL2 specimens were brushed with 4% chlorhexidine (1 min), immersed in the same solution (10 min) and immersed in water (3 min); MW2 specimens were immersed in water and microwave irradiated (650W; 6 min); CL2 and MW2 specimens were disinfected twice; CL7 and MW7 specimens were submitted to seven cycles using chlorhexidine or microwave irradiation, respectively; W specimens were not disinfected and remained in water (37°C; 7 days). Results: Results were statistically analysed (p = 0.05) and revealed that, at baseline, the highest mean value was observed for T (p < 0.001). Material NT showed increase in roughness after the first (p = 0.003), second (p = 0.001), seventh (p = 0.000) cycles of microwave disinfection and after 7 days of immersion in water (p = 0.033). Conclusions: Resilient liner S presented significant increase in roughness after the second cycle of disinfection with chlorhexidine (p = 0.003). Material T exhibited significantly decreased roughness in group W (p = 0.010), while microwaving produced severe alterations on its surface.     

Circadian preference is associated with emotional and affective temperaments

Chronotype has long been associated with mental disorders and temperamental features. This study aims to investigate the association of circadian preference with a new model for emotional and affective temperament. In this Web survey, 6436 subjects (27.2% males) answered the Affective and Emotional Composite Temperament Scale (AFECTS), the Circadian Energy Scale (CIRENS), and questions on subjective sleep parameters for a sleep-based chronotype measure. Temperament was more strongly correlated with daily energy score than with chronotype. For emotional dimensions, Volition, Coping, and Control positively correlated with high and stable daily energy, contrary to Sensitivity. Evening types showed a less adaptive emotional profile than morning and intermediate types, who showed a relatively similar emotional pattern. Focus and order (facets of Control), energy (facet of Volition), caution (facet of Inhibition), and problem facing (facet of Coping) were distinctive for the three circadian types, being particularly low in evening types and high in morning types. Differences between affective temperaments were more pronounced for morning and afternoon than for evening scores. Cyclothymic and euphoric temperaments, which relate to bipolar disorders, and apathetic, volatile, and disinhibited temperaments, which relate to attention-deficit/hyperactivity disorder (ADHD), showed the latest chronotype (i.e., evening preference). In conclusion, temperament was more associated with absolute energy levels than with chronotype. Evening types had less emotional control, coping, volition, and caution, and more affective instability and externalization. The circadian daily energy profile can be very informative about human temperament and vice versa, and their combined assessment may be useful in the evaluation of psychiatric patients.