COMPARAÇÃO de Métodos de Conservação sobre Os Processos Fisiológicos E bioquímicos Relacionados Com características Essenciais à Qualidade E comercialização do Mamão Carica Papaya L.

RESUMO O mamão é um fruto climatérico de difícil manejo nas etapas entre a colheita e o mercado consumidor. Durante o amadurecimento os polissacarídeos da parede celular, responsáveis pela textura dos frutos, são degradados por enzimas hidrolíticas (pectinametilesterase (PME), b-galactosidase (b-gal) e celulase), o que acarreta perda da textura. Este trabalho comparou o efeito de três métodos de conservação sobre os processos bioquímicos/fisiológicos relacionados com características essenciais à qualidade e comercialização do mamão Carica papaya L. da cultivar Golden. Os frutos foram colhidos no estádio 1 de maturação e separados em 3 grupos: (C) controle - lavagem em água clorada; (TP) tratamento padrão - tipo exportação; (I) irradiado - radiação gama 0,8kGy. Os frutos foram mantidos em condições naturais de amadurecimento e as características organolépticas e as atividades de enzimas de parede celular foram avaliadas. Os frutos do grupo I apresentaram maior textura e menor atividade da PME, b-gal e celulase, o que sugere que a radiação gama retarda o amadurecimento dos frutos pela redução da atividade destas enzimas. O teor de carboidrato foi semelhante para todos os grupos (@11,57 g/100g polpa) quando estes atingiram textura ideal para o consumo, 4º, 6º e 10º dia pós-colheita para frutos dos grupos TP, C e I respectivamente. Esses resultados mostram que a radiação gama foi o tratamento mais eficiente entre os testados, uma vez que forneceu um ganho de 4 e 6 dias de conservação quando comparados aos frutos dos grupos C e TP respectivamente, sem o comprometimento de características sensoriais e nutricionais. Palavras-chave: Radiação gama, enzimas, pectina, mamão, tecnologia pós-colheita

TLR2, TLR4 and Protein kinase R (PKR) induced Type I Interferon sustains infection of Leishmania donovani in macrophages

Leishmania donovani is a protozoan parasite that causes visceral leishmaniasis, provoking liver and spleen tissue destruction that is lethal unless treated. The parasite replicates in macrophages and modulates host microbicidal responses. We have previously reported that neutrophil elastase (NE) is required to sustain L. donovani intracellular growth in macrophages through the induction of interferon beta (IFN-β). Here, we show that the gene expression of IFN-β by infected macrophages was reduced by half when TLR4 was blocked by pre-treatment with neutralizing antibodies or in macrophages from tlr2 (-/-) mice, while the levels in macrophages from myd88(-/-) mice were comparable to those from wild-type C57BL/6 mice. The neutralization of TLR4 in tlr2 (-/-) macrophages completely abolished induction of IFN-β gene expression upon parasite infection, indicating an additive role for both TLRs. Induction of type I interferon (IFN-I), OASL2, SOD1, and IL10 gene expression by L. donovani was completely abolished in macrophages from NE knock-out mice (ela2 (-/-)) or from protein kinase R (PKR) knock-out mice (pkr (-/-)), and in C57BL/6 macrophages infected with transgenic L. donovani expressing the inhibitor of serine peptidase 2 (ISP2). Parasite intracellular growth was impaired in pkr (-/-) macrophages but was fully restored by the addition of exogenous IFN-β, and parasite burdens were reduced in the spleen of pkr (-/-) mice at 7 days, as compared to the 129Sv/Ev background mice. Furthermore, parasites were unable to grow in macrophages lacking TLR3, which correlated with lack of IFN-I gene expression. Thus, L. donovani engages innate responses in infected macrophages via TLR2, TLR4, and TLR3, via downstream PKR, to induce the expression of pro-survival genes in the host cell, and guarantee parasite intracellular development

Synthesis, characterization, antibacterial and antitumoral activities of mononuclear zinc complexes containing tridentate amine based ligands with N3 or N2O donor groups

The synthesis and characterization of the four zinc(II) complexes [Zn(HL1)Cl-2] (1), [Zn(H2L2)Cl-2](2), [Zn(H2L3)Cl-2] (3) and[Zn(H2L4)Cl-2] (4), where HL1 = (bis-2-pyridylmethyl)amine, H2L2 = (2-hydroxybenzyl- 2-pyridylmethyl) amine, H2L3 = N-2[(pyridine-2-ylmethyl)amino)ethanol, H2L4 = 1-[(pyridine-2-ylmethyl)- amino]-propan-2-ol are reported; (3) and (4) are new while (2) was reported previously but its structure had not been determined. The complexes were characterized by elemental analysis, IR, UV-Vis and NMR spectroscopic, electrospray ionization mass spectrometry (ESI(+)-MS) and tandem mass spectrometry ESI(+)-MS/MS). X-ray diffraction studies were performed for complexes (1)-(3) revealing the presence of mononuclear structures in the solid state. The X-ray analyses of (1) and (3) demonstrate that HL1 and HL2 act as tridentate ligands, while the ligand H2L2 in (2) is bidentate. The cytotoxic properties of the ligands and of all the complexes were examined using human leukemia THP-1, U937 and Molt-4 cells. Complex (4) exhibited the highest cytotoxicity in this series with an IC50 value of 75 +/- 1 mu mol L (1) against U937 cells. Transmission electron microscopy (TEM) reveals ultrastructural changes typical of apoptotic cells. The induction of apoptosis was confirmed by the annexin V assay. The antimicrobial activity of complexes (1)-(4) was also investigated in vitro against four Gram-positive bacteria (ATCC10832, ATCC25923, COL) and the clinical Staphylococcus aureus isolate LSA88 (SEC/SEF/ TSST-1+). Complex (2) showed the most potent inhibitory activity, reaching almost 100% of inhibition against all strains tested. Morphological investigations using TEM indicate that the antibacterial activity of complex (2) may be associated with the inhibition of cell wall and therefore cell division. (C) 2014 Elsevier B. V. All rights reserved

Regulation of Stress-Inducible Phosphoprotein 1 Nuclear Retention by Protein Inhibitor of Activated STAT PIAS1

Stress-inducible phosphoprotein 1 (STI1), a cochaperone for Hsp90, has been shown to regulate multiple pathways in astrocytes, but its contributions to cellular stress responses are not fully understood. We show that in response to irradiation-mediated DNA damage stress STI1 accumulates in the nucleus of astrocytes. Also, STI1 haploinsufficiency decreases astrocyte survival after irradiation. Using yeast two-hybrid screenings we identified several nuclear proteins as STI1 interactors. Overexpression of one of these interactors, PIAS1, seems to be specifically involved in STI1 nuclear retention and in directing STI1 and Hsp90 to specific sub-nuclear regions. PIAS1 and STI1 co-immunoprecipitate and PIAS1 can function as an E3 SUMO ligase for STI. Using mass spectrometry we identified five SUMOylation sites in STI1. A STI1 mutant lacking these five sites is not SUMOylated, but still accumulates in the nucleus in response to increased expression of PIAS1, suggesting the possibility that a direct interaction with PIAS1 could be responsible for STI1 nuclear retention. To test this possibility, we mapped the interaction sites between PIAS1 and STI1 using yeast-two hybrid assays and surface plasmon resonance and found that a large domain in the N-terminal region of STI1 interacts with high affinity with amino acids 450-480 of PIAS1. Knockdown of PIAS1 in astrocytes impairs the accumulation of nuclear STI1 in response to irradiation. Moreover, a PIAS1 mutant lacking the STI1 binding site is unable to increase STI1 nuclear retention. Interestingly, in human glioblastoma multiforme PIAS1 expression is increased and we found a significant correlation between increased PIAS1 expression and STI1 nuclear localization. These experiments provide evidence that direct interaction between STI1 and PIAS1 is involved in the accumulation of nuclear STI1. This retention mechanism could facilitate nuclear chaperone activity. Molecular & Cellular Proteomics 12: 10.1074/mcp.M113.031005, 3253-3270, 2013

The European Union and United Kingdom's deforestation-free supply chains regulations : implications for Brazil

This paper analyses the potential implications of the proposed European Union Deforestation Regulation (EUDR) and the recently adopted United Kingdom (UK) legislation on deforestation-free supply chains (henceforth ‘the legislation’) for different stakeholders in Brazil. These regulations intend to address global commodity-driven deforestation and forest degradation by ensuring that targeted commodities and products placed on (or exported from) markets are of minimal risk of being associated with - in the EU - deforestation and forest degradation or - in the UK - illegal deforestation. The paper examines potential compliance readiness in cattle, cocoa, coffee, palm oil, soybean and tropical timber supply chains in Brazil, indicating specific challenges that may arise. Through the construction of a “Compliance Likelihood Index”, our research provides comparable indications to policymakers on sectors and stakeholders that may need stronger support to meet the requirements, in order to maintain Brazil's access to EU and UK markets. The paper indicates that coffee is the sector with the highest level of incentivization and smallest hurdles for compliance, while the cattle sector may face stronger challenges to rapidly adjust its production system towards a deforestation-free value chain and prove compliance. Results of our analysis also highlight the need for collaboration between the EU/UK and Brazil in order to promote alignment between domestic and demand-side legislations so that they are mutually reinforcing. Results of this exercise, which has a focus on the producer-country view of demand-side legislation, will contribute to discussions on the merits of different approaches to strengthen the governance of deforestation-risk commodity trade

Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl groups via interaction with death receptors

The synthesis, physico-chemical characterization and cytotoxicity of four new ligands and their respective copper(II) complexes toward two human leukemia cell lines (THP-1 and U937) are reported (i.e. [(HL1) Cu(mu-Cl)(2)Cu(HL1)]Cl-2 center dot H2O (1), [(H2L2)Cu(mu-Cl)(2)Cu(H2L2)]Cl-2 center dot 5H(2)O (2), [(HL3)Cu(mu-Cl)(2)Cu(HL3)]Cl-2 center dot 4H(2) (3), [(H2L4)Cu(mu-Cl)(2)Cu(H2L4)]Cl-2 center dot 6H(2)O (4)). Ligands HL1 and HL3 contain two pyridines, amine and alcohol moieties with a naphthyl pendant unit yielding a N3O coordination metal environment Ligands H2L2 and H2L4 have pyridine, phenol, amine and alcohol groups with a naphthyl pendant unit providing a N2O2 coordination metal environment These compounds are likely to be dinuclear in the solid state but form mononuclear species in solution. The complexes have an antiproliferative effect against both leukemia cell lines; complex (2) exhibits higher activity than cisplatin against U937 (8.20 vs 16.25 mu mol dm(-3)) and a comparable one against THP-1. These human neoplastic cells are also more susceptible than peripheral blood mononuclear cells (PBMCs) toward the tested compounds. Using C57BL/6 mice an LD50 of 55 mg kg(-1) was determined for complex (2), suggesting that this compound is almost four times less toxic than cisplatin (LD50 = 14.5 mg kg(-1)). The mechanism of cell death promoted by ligand H2L2 and by complexes (2) and (4) was investigated by a range of techniques demonstrating that the apoptosis signal triggered at least by complex (2) starts from an extrinsic pathway involving the activation of caspases 4 and 8. This signal is amplified by mitochondria with the concomitant release of cytochrome c and the activation of caspase 9. (C) 2015 Elsevier Inc. All rights reserved

Dynamics of the Leaf-Litter Arthropod Fauna Following Fire in a Neotropical Woodland Savanna

Fire is an important agent of disturbance in tropical savannas, but relatively few studies have analyzed how soil-and-litter dwelling arthropods respond to fire disturbance despite the critical role these organisms play in nutrient cycling and other biogeochemical processes. Following the incursion of a fire into a woodland savanna ecological reserve in Central Brazil, we monitored the dynamics of litter-arthropod populations for nearly two years in one burned and one unburned area of the reserve. We also performed a reciprocal transplant experiment to determine the effects of fire and litter type on the dynamics of litter colonization by arthropods. Overall arthropod abundance, the abundance of individual taxa, the richness of taxonomic groups, and the species richness of individual taxa (Formiciade) were lower in the burned site. However, both the ordinal-level composition of the litter arthropod fauna and the species-level composition of the litter ant fauna were not dramatically different in the burned and unburned sites. There is evidence that seasonality of rainfall interacts with fire, as differences in arthropod abundance and diversity were more pronounced in the dry than in the wet season. For many taxa the differences in abundance between burned and unburned sites were maintained even when controlling for litter availability and quality. In contrast, differences in abundance for Collembola, Formicidae, and Thysanoptera were only detected in the unmanipulated samples, which had a lower amount of litter in the burned than in the unburned site throughout most of our study period. Together these results suggest that arthropod density declines in fire-disturbed areas as a result of direct mortality, diminished resources (i.e., reduced litter cover) and less favorable microclimate (i.e., increased litter desiccation due to reduction in tree cover). Although these effects were transitory, there is evidence that the increasingly prevalent fire return interval of only 1–2 years may jeopardize the long-term conservation of litter arthropod communities

Pathogen-Induced Proapoptotic Phenotype and High CD95 (Fas) Expression Accompany a Suboptimal CD8+ T-Cell Response: Reversal by Adenoviral Vaccine

MHC class Ia-restricted CD8+ T cells are important mediators of the adaptive immune response against infections caused by intracellular microorganisms. Whereas antigen-specific effector CD8+ T cells can clear infection caused by intracellular pathogens, in some circumstances, the immune response is suboptimal and the microorganisms survive, causing host death or chronic infection. Here, we explored the cellular and molecular mechanisms that could explain why CD8+ T cell-mediated immunity during infection with the human protozoan parasite Trypanosoma cruzi is not optimal. For that purpose, we compared the CD8+ T-cell mediated immune responses in mice infected with T. cruzi or vaccinated with a recombinant adenovirus expressing an immunodominant parasite antigen. Several functional and phenotypic characteristics of specific CD8+ T cells overlapped. Among few exceptions was an accelerated expansion of the immune response in adenoviral vaccinated mice when compared to infected ones. Also, there was an upregulated expression of the apoptotic-signaling receptor CD95 on the surface of specific T cells from infected mice, which was not observed in the case of adenoviral-vaccinated mice. Most importantly, adenoviral vaccine provided at the time of infection significantly reduced the upregulation of CD95 expression and the proapoptotic phenotype of pathogen-specific CD8+ cells expanded during infection. In parallel, infected adenovirus-vaccinated mice had a stronger CD8 T-cell mediated immune response and survived an otherwise lethal infection. We concluded that a suboptimal CD8+ T-cell response is associated with an upregulation of CD95 expression and a proapoptotic phenotype. Both can be blocked by adenoviral vaccination