Helicobacter pylori cag pathogenicity island-positive strains induce syndecan-4 expression in gastric epithelial cells

Helicobacter pylori is recognized as the main cause of gastritis and is associated with gastric carcinogenesis. Syndecan-4 represents the major source of heparan sulfate (HS) in the gastric cells. HS proteoglycans expressed on the cell surface constitute targets for H. pylori at the early stage of infection. The aim of this study was to determine whether H. pylori induction of syndecan-4 expression is affected by the virulence characteristics of the infecting strain, namely the cytotoxic-associated gene ( cag ) pathogenicity island (PAI). We observed that individuals infected with highly pathogenic H. pylori strains express syndecan-4 in the foveolar epithelium of the gastric mucosa. The association between the cag PAI status of the infecting strain and syndecan-4 expression was further demonstrated by infection of gastric epithelial cell lines with a panel of cag PAI⁺ and cag PAI⁻ H. pylori strains, showing that expression of syndecan-4 was significantly increased in response to infection with the highly pathogenic strains. Moreover, infection of gastric cells with cag A and cag E mutant strains further confirmed that syndecan-4 induction is dependent on an intact cag PAI. The present study shows that highly pathogenic H. pylori strains induce syndecan-4 expression, both in human gastric mucosa and in gastric cell lines, in a cag PAI-dependent manner.     

Evaluation of childhood acute leukemia incidence and underreporting in Brazil by capture–recapture methodology

Background: Population-based cancer registries (PBCR) are important in cancer epidemiology as they provide the basis for monitoring cancer incidence. Childhood acute lymphoblastic leukemia (ALL) is said to have lower incidence in developing countries, which has implications for its pathogenesis, but there are few studies concerning the completeness of cancer registries in developing countries. This study analyzes the number of cases and incidence of childhood acute lymphoblastic leukemia in three different cities in Brazil and estimates underreporting cases and possible PBCR failures. Methods: We evaluated the completeness of PBCR and the incidence rates of childhood ALL from three different Brazilian cities using the two-source capture–recapture method. The sources used were a population-based registry and databases from a diagnosis reference laboratory in 2001 and the Chapman's formula was used to calculate the estimates. Results: The estimated incidence was 5.76, 6.32 and 5.48 per 100,000 inhabitants for Salvador, Recife and Belo Horizonte, respectively. The estimated completeness of childhood ALL in PBCRs was 15.5%, 35.4% and 29.2%, respectively, for Salvador, Recife and Belo Horizonte. Conclusions: There was a high estimated underreporting of childhood leukemia cases in some Brazilian cities. The relationship between information systems and the capture–recapture method application improved epidemiological estimates. Childhood acute lymphoblastic leukemia incidence rates are similar to those of developed countries.     

Antioxidant Activity of Vitamin E and Trolox: Understanding of the Factors that Govern Lipid Peroxidation Studies In Vitro

Peroxidation of lipids is of significant interest owing to the evidence that peroxyl radicals and products of lipid peroxidation may be involved in the toxicity of compounds initiating a deteriorative reaction in the processing and storage of lipid-containing foods. In view of the significance of the antioxidant role of the dietary compound vitamin E and its water-soluble analogue Trolox in research of lipid-containing foods, it is desirable to determine more specifically how and where they operate its antioxidant activity in lipid membranes. In this study, unilamellar liposomes of phosphatidylcholine were used as membrane mimetic systems to estimate the antioxidant properties of vitamin E and Trolox and establish a relationship between their interactions with the membrane and their consequent antioxidant activity. Lipid peroxidation was initiated by the peroxyl radical (ROO^•) in lipid and aqueous media by the thermal decomposition of azocompounds and was assessed by the fluorescence intensity decay of the fluorescent probe diphenylhexatriene propionic acid. Results obtained showed that membrane lipoperoxidation is related not only to the scavenging characteristics of the compounds studied but also to their ability to interact with the lipid bilayers, and consequently liposomes provide additional information to that obtained currently from assays performed in aqueous buffer media.     

Development and characterization of microsatellite markers for the Brazil nut tree Bertholletia excelsa Humb. & Bonpl. (Lecythidaceae)

Twelve polymorphic microsatellite markers were developed for the Brazil nut (Bertholletia excelsa), one of the most valuable non‐timber forest products from the Amazon, based on enrichment protocol. Six to 18 (mean 10.4) alleles per locus were identified and the expected heterozygosity ranged from 0.663 to 0.923 based on a screen of 40 individuals from one population of B. excelsa. The combined probabilities of genetic identity (8.39 × 10^?17) and paternity exclusion (0.999999) indicated that multilocus genotypes are likely to be unique allowing precise analyses of genetic structure, gene flow, and mating system of this economically important species.     

Weight Change in Monozygotic Twins Treated with Valproate

Objective: To evaluate whether genetic factors contribute to weight gain associated with valproate (VPA) therapy. Research Methods and Procedures: We retrospectively and prospectively evaluated five pairs of monozygotic twins concordant for epilepsy and treated with VPA regarding weight course. Results: In all twin pairs, both twins showed similar weight courses under therapy with VPA. Discussion: These results suggest that genetic factors may have an influence on the weight change induced by VPA. Further studies are necessary to obtain heritability estimates regarding this effect of VPA therapy and to identify the relevant genes.     

Evaluation of rhizobacteria in upland rice in Brazil: growth promotion and interaction of induced defense responses against leaf blast (<Emphasis Type="Italic">Magnaporthe oryzae</Emphasis>)

Blast and the initial vigor of upland rice plants are the main challenges facing rice crops in Brazilian no-tillage systems. The aim of this study was to evaluate the growth promotion and interactions of defense responses against Magnaporthe oryzae in rice plants treated with rhizobacteria Bacillus sp. (BRM 32110) and Serratia sp. (BRM 32114). The seeds of the rice were microbiolized, and 14 days after the plants emerged, the soil was drenched with rhizobacterial suspensions. Growth promotion was evaluated by root and shoot biomass, root and shoot length, foliar area, and nitrate reductase (NR) activity. The defense response was evaluated by quantification of the rice blast severity (RBS), disease progress, pathogenesis-related protein (PRP) activity, and salicylic acid content (SA). The length and biomass of the roots and shoots and the foliar area of the plants treated with BRM 32114 isolate increased; however, the NR activity was 43% lower compared to the control. Both isolates reduced the severity and progress of the disease. Principal component analysis showed that RBS, β-1,3-glucanase (GLU), peroxidase (POX), and phenylalanine ammonia lyase (PAL) were the main sources of the first components of variance, whereas lipoxygenase (LOX) and SA were the main sources of the second components and were negatively correlated. Serratia sp. isolate BRM 32114 can be used as a growth-promoting agent and has potential for inducing resistance in rice plants. The results suggest that the interaction among the levels and timing of the PRP activity and the levels of SA play important roles in the defense responses against M. oryzae.     

Putrescine promotes changes in the endogenous polyamine levels and proteomic profiles to regulate organogenesis in <Emphasis Type="Italic">Cedrela fissilis</Emphasis> Vellozo (Meliaceae)

Improvements to in vitro organogenesis are essential for optimizing shoot development and understanding basic physiological processes. The addition of polyamines (PAs) to the culture medium has been used to modulate organogenesis in plants, and this work evaluated the effects of exogenous PAs on direct organogenesis from apical and cotyledonary nodal Cedrela fissilis explants as well as the effects of putrescine (Put) on endogenous PA levels and variations in protein abundance. The effects of exogenous Put, spermidine, and spermine at 0, 0.5, 1, 2.5, or 5 mM on shoot development were tested. The comparison of the tested PAs to the control treatment revealed that 2.5 mM Put significantly increased the length of shoots from cotyledonary nodal explants, which are more sensitive than apical nodal explants, and treatment with 2.5 mM Put significantly increased the endogenous total free-PA and free-Put levels in shoots compared with the control (no Put). A comparative proteomic analysis of shoots indicated that 2.5 mM Put significantly changed the abundance of proteins, primarily metabolic and cellular proteins associated with stress and energy processes such as cell division. These results show that Put functions in endogenous PA metabolism and alters protein abundance, thereby contributing to shoot development in C. fissilis.     

Octopus: a platform for the virtual high-throughput screening of a pool of compounds against a set of molecular targets

Octopus is an automated workflow management tool that is scalable for virtual high-throughput screening (vHTS). It integrates MOPAC2016, MGLTools, PyMOL, and AutoDock Vina. In contrast to other platforms, Octopus can perform docking simulations of an unlimited number of compounds into a set of molecular targets. After generating the ligands in a drawing package in the Protein Data Bank (PDB) format, Octopus can carry out geometry refinement using the semi-empirical method PM7 implemented in MOPAC2016. Docking simulations can be performed using AutoDock Vina and can utilize the Our Own Molecular Targets (OOMT) databank. Finally, the proposed software compiles the best binding energies into a standard table. Here, we describe two successful case studies that were verified by biological assay. In the first case study, the vHTS process was carried out for 22 (phenylamino)urea derivatives. The vHTS process identified a metalloprotease with the PDB code 1GKC as a molecular target for derivative LE&007. In a biological assay, compound LE&007 was found to inhibit 80% of the activity of this enzyme. In the second case study, compound Tx001 was submitted to the Octopus routine, and the results suggested that Plasmodium falciparum ATP6 (PfATP6) as a molecular target for this compound. Following an antimalarial assay, Tx001 was found to have an inhibitory concentration (IC₅₀) of 8.2 μM against PfATP6. These successful examples illustrate the utility of this software for finding appropriate molecular targets for compounds. Hits can then be identified and optimized as new antineoplastic and antimalarial drugs. Finally, Octopus has a friendly Linux-based user interface, and is available at www.drugdiscovery.com.br.

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Graphical Abstract Octopus: A platform for inverse virtual screening (IVS) to search new molecular targets for drugs.

     

<Emphasis Type="Italic">Azospirillum</Emphasis> spp. from native forage grasses in Brazilian Pantanal floodplain: biodiversity and plant growth promotion potential

A sustainable alternative to improve yield and the nutritive value of forage is the use of plant growth-promoting bacteria (PGPB) that release nutrients, synthesize plant hormones and protect against phytopathogens (among other mechanisms). Azospirillum genus is considered an important PGPB, due to the beneficial effects observed when inoculated in several plants. The aim of this study was to evaluate the diversity of new Azospirillum isolates and select bacteria according to the plant growth promotion ability in three forage species from the Brazilian Pantanal floodplain: Axonopus purpusii, Hymenachne amplexicaulis and Mesosetum chaseae. The identification of bacterial isolates was performed using specific primers for Azospirillum in PCR reactions and partial sequencing of the 16S rRNA and nifH genes. The isolates were evaluated in vitro considering biological nitrogen fixation (BNF) and indole-3-acetic acid (IAA) production. Based on the results of BNF and IAA, selected isolates and two reference strains were tested by inoculation. At 31 days after planting the plant height, shoot dry matter, shoot protein content and root volume were evaluated. All isolates were able to fix nitrogen and produce IAA, with values ranging from 25.86 to 51.26 mg N mL^?1 and 107–1038 µmol L^?1, respectively. The inoculation of H. amplexicaulis and A. purpusii increased root volume and shoot dry matter. There were positive effects of Azospirillum inoculation on Mesosetum chaseae regarding plant height, shoot dry matter and root volume. Isolates MAY1, MAY3 and MAY12 were considered promising for subsequent inoculation studies in field conditions.