Contextual binding of p120ctn to E-cadherin at the basolateral plasma membrane in polarized epithelia

E-cadherin-catenin complexes mediate cell-cell adhesion on the basolateral membrane of epithelial cells. The cytoplasmic tail of E-cadherin supports multiple protein interactions, including binding of beta-catenin at the C terminus and of p120(ctn) to the juxtamembrane domain. The temporal assembly and polarized trafficking of the complex or its individual components to the basolateral membrane are not fully understood. In Madin-Darby canine kidney cells at steady state and after treatment with cycloheximide or temperature blocks, E-cadherin and beta-catenin localized to the Golgi complex, but p120ctn was found only at the basolateral plasma membrane. We previously identified a dileucine sorting motif (Leu(586)-Leu(587), termed S1) in the juxtamembrane domain of E-cadherin and now show that it is required to target full-length E-cadherin to the basolateral membrane. Removal of S1 resulted in missorting of E-cadherin mutants (EcadDeltaS1) to the apical membrane; beta-catenin was simultaneously missorted and appeared at the apical membrane. p120(ctn) was not mistargeted with EcadDeltaS1, but could be recruited to the E-cadherin-catenin complex only at the basolateral membrane. These findings help define the temporal assembly and sorting of the E-cadherin-catenin complex and show that membrane recruitment of p120(ctn) in polarized cells is contextual and confined to the basolateral membrane.

Dietary interactions influence the effects of bovine folate-binding protein on the bioavailability of tetrahydrofolates in rats

The newborns of mammals have a high folate demand, yet obtain adequate folate nutrition solely from their mothers' milk despite its low folate content. Milk folate is entirely bound by an excess of folate-binding protein (FBP), prompting speculation that FBP may affect the bioavailability of the limited folate supply. Previous research has shown that FBP-bound folic acid is more gradually absorbed, thereby reducing the peak plasma folate concentration and preventing loss into the urine. Natural folates are reduced derivatives of folic acid, with milk predominantly containing 5-methyltetrahydrofolate, yet little research has been carried out to determine the role of FBP in the bioavailability of reduced folates. We studied the effect of FBP on folate nutrition of rats in both single-dose and 4-wk feeding experiments. The effect of FBP was influenced by the presence of other milk components. FBP increased bioavailability of dietary folate when it was consumed with other whey proteins or with soluble casein. However, in the presence of acid-precipitated casein or a whey preparation enriched in lipids, bioavailability was decreased. These results highlight the difficulties of extrapolating from experimental results obtained using purified diets alone and of studying interactions among dietary components. They suggest that the addition of FBP-rich foods to folate-rich foods could enhance the bioavailability of natural folates, but that the outcome of such a combination would depend on interactions with other components of the diet.

Greater replication and differentiation of preadipocytes in inherited corticosteroid-binding globulin deficiency

Glucocorticoids are pivotal for adipose tissue development. Rodent studies suggest that corticosteroid-binding globulin (CBG) modulates glucocorticoid action in adipose tissue. In humans, both genetic CBG deficiency and suppressed CBG concentrations in hyperinsulinemic states are associated with obesity. We hypothesized that CBG deficiency in humans modulates the response of human preadipocytes to glucocorticoids, predisposing them to obesity. We compared normal preadipocytes with subcultured preadipocytes from an individual with the first ever described complete deficiency of CBG due to a homozygous null mutation. CBG-negative preadipocytes proliferated more rapidly and showed greater peroxisome proliferator-activated receptor-gamma-mediated differentiation than normal preadipocytes. CBG was not expressed in normal human preadipocytes. Glucocorticoid receptor number and binding characteristics and 11beta-hydroxysteroid dehydrogenase activity were similar for CBG-negative and normal preadipocytes. We propose that the increased proliferation and enhanced differentiation of CBG-negative preadipocytes may promote adipose tissue deposition and explain the obesity seen in individuals with genetic CBG deficiency. Furthermore, these observations may be relevant to obesity occurring with suppressed CBG concentrations associated with hyperinsulinemia.

χ-conopeptide MrIA partially overlaps desipramine and cocaine binding sites on the human norepinephrine transporter

The interactions of chi-conopeptide MrIA with the human norepinephrine transporter (hNET) were investigated by determining the effects of hNET point mutations on the inhibitory potency of MrIA. The mutants were produced by site-directed mutagenesis and expressed in COS-7 cells. The potency of MrIA was greater for inhibition of uptake by hNET of [H-3] norepinephrine (K-i 1.89 muM) than [H-3] dopamine (K-i 4.33 muM), and the human dopamine transporter and serotonin transporter were not inhibited by MrIA ( to 7 muM). Of 18 mutations where hNET amino acid residues were exchanged with those of the human dopamine transporter, MrIA had increased potency for inhibition of [H-3] norepinephrine uptake for three mutations ( in predicted extracellular loops 3 and 4 and transmembrane domain (TMD) 8) and decreased potency for one mutation (in TMD6 and intracellular loop (IL) 3). Of the 12 additional mutations in TMDs 2, 4, 5, and 11 and IL1, three mutations (in TMD2 and IL1) had reduced MrIA inhibitory potency. All of the other mutations tested had no influence on MrIA potency. A comparison of the results with previous data for desipramine and cocaine inhibition of norepinephrine uptake by the mutant hNETs reveals that MrIA binding to hNET occurs at a site that is distinct from but overlaps with the binding sites for tricyclic antidepressants and cocaine.

Identification of slow and fast-acting toxins in a highly ciguatoxic barracuda (Sphyraena barracuda) by HPLC/MS and radiolabelled ligand binding

A barracuda implicated in ciguatera fish poisoning in Guadeloupe was estimated to have an overall flesh toxicity of 15 MUg/g using mouse bioassay. A lipid soluble extract was separated into two toxic fractions, FrA and FrB, on a LH20 Sephadex column eluted with dichloromethane/methanol (1:1). When intraperitoneal injected into mice, FrA provoked symptoms characteristic of slow-acting ciguatoxins, whereas FrB produced symptoms indicative of fast-acting toxins (FAT). High performance liquid chromatography/mass spectrometry/radio-ligand binding (HPLC/MS/RLB) analysis confirmed the two fractions were distinct, because only a weak overlap of some compounds was observed. HPLC/MS/RLB analysis revealed C-CTX-1 as the potent toxin present in FrA, and two coeluting active compounds at m/z 809.43 and 857.42 in FrB, all displaying the characteristic pattern of ion formation for hydroxy-polyethers. Other C-CTX congeners and putative hydroxy-polyether-like compounds were detected in both fractions, however, the RLB found them inactive. C-CTX-1 accounted for >90% of total toxicity in this barracuda and was confirmed to be a competitive inhibitor of brevetoxin binding to voltage-sensitive sodium channels (VSSCs) with a potency two-times lower than P-CTX-1. However, FAT active on VSSCs and

O mar não está para peixe : uma etnografia dos conflitos socioambientais em torno da Zona de Proteção Marinha e da comunidade pesqueira do Bugigão – RESEXMAR do Corumbau/Bahia.

A Reserva Extrativista Marinha (RESEXMAR) do Corumbau foi criada no ano de 2000, a partir de uma ação coletiva, iniciada em 1997 por meio das lideranças de pescadores locais, na busca de instrumento jurídico que garantisse o acesso exclusivo dos recursos pesqueiros contra a atividade da pesca comercial de camarão sete-barbas que se instalou na década de 1980. Durante o processo de criação da RESEXMAR do Corumbau, os pescadores obtiveram apoio de órgãos governamentais, como a Coordenação Nacional de Populações Tradicionais (CNPT) e de entidades ambientalistas do terceiro setor – Associação Pradense de Proteção Ambiental (APPA), e posteriormente a Conservation International do Brasil (CI-Brasil). Entretanto, após a criação da RESEXMAR do Corumbau – entre os anos 2000 e 2002 – foi elaborado o Plano de Manejo que orientaria a gestão da Unidade de Conservação (UC). O documento foi capitaneado pela equipe técnica e científica vinculada à CI-Brasil, tendo como ponto de destaque a criação de áreas de exclusão total da atividade da pesca, por meio da Zona de Proteção Marinha (ZPM). A ideia de uma ZPM, para a CI-Brasil, era que de forma indireta e em médio e longo prazo, os pescadores se beneficiariam com o possível aumento de produção de pescado, contanto que 30% de cobertura de recifes tivesse algum tipo de proteção dos processos ecológicos, tais como reprodução e crescimento de espécies. Durante as discussões do Plano de Manejo e atualmente uma parcela de pescadores locais contestaram os limites da ZPM, pois iria restringir o acesso aos recursos pesqueiros. No entanto, tal contestação foi suprimida pelas relações não formais que os membros da CI-Brasil possuíam com o núcleo familiar principal da Vila do Corumbau, forçando os demais em um acordo formal temporário. Tal questionamento evidenciou um conflito de conjunto de normas distintas entre pescadores artesanais em relação à CI-Brasil e IBAMA: a pesca artesanal ‒ um tipo de ação que segue normas específicas das quais elementos humanos e não humanos interagem conjuntamente, evidenciando um conhecimento prático e corporizado constituindo um modelo compreensivo de mundo e de natureza; conceitos modernos e globalizantes de uma natureza totalmente desvinculada das práticas locais artesanais, com forte articulação de uma entidade ambientalista de alcance internacional, guiada pela emergência das questões ambientais, imprimindo no local (o lugar da prática da pesca tradicional) a ideia de um espaço (Áreas Marinhas Protegidas), desencaixado de formas específicas de natureza/culturas.

A concordância nominal de número no português falado na zona rural de Santa Leopoldina/ES

Esta pesquisa dedica-se a analisar o processo de concordância nominal no português falado na zona rural de Santa Leopoldina/ES. Para isso, utilizaremos, como base para nossas ponderações, os pressupostos da Sociolinguística Variacionista. Nossa análise foi constituída a partir de entrevistas, tipicamente labovianas, com duração de 50 a 60 minutos. Sabendo que a Teoria da Variação considera preponderante o estudo da língua associado ao meio em que essa se encontra inserida, nos termos de Labov (2008 [1972], p. 291), estratificamos nossos informantes da seguinte maneira: faixa etária – 7-14 anos; 15-25 anos; 26-49 anos; e maiores de 49 anos; sexo/gênero – feminino e masculino; escolaridade – um a cinco anos (antigo primário, atual fundamental 1); seis a nove anos (antigo ginasial, atual fundamental 2). Para um controle do ambiente linguístico em que nossas variantes operam, selecionamos cinco variáveis linguísticas: saliência fônica, posição linear e relativa aliada à classe gramatical, marcas precedentes, animacidade dos substantivos, grau e formalidade dos substantivos e dos adjetivos. Além disso, elaboramos um estudo comparativo entre rural vs urbano, haja vista que comparamos nossos resultados aos obtidos por: Scherre (1988) – com o português falado no Rio de Janeiro (RJ), na década de 1980; Scherre e Naro (2006) – com o português falado no Rio de Janeiro (RJ), na década de 2000; e, por fim, Silva (2011) – com o português falado em Vitória (ES), na década de 2000. Esperamos, dessa forma, colaborar para o mapeamento da fala capixaba.

Desempenho de genótipos de feijão-mungo-verde semeados no inverno na Zona da Mata de Minas Gerais

Avaliou-se o desempenho do feijão-mungo-verde, semeado no inverno, na Zona da Mata de Minas Gerais, a 400 (Oratórios) e 720 m (Coimbra) de altitude. Dez genótipos foram semeados no final de julho, ou no início de agosto, no delineamento em blocos ao acaso, com quatro repetições. Irrigações por aspersão complementaram as chuvas. A primeira vagem amadureceu aos 73,3 (Oratórios) e aos 79,9 dias após a emergência (DAE) (Coimbra). A altura das plantas foi maior em Oratórios (62,4 cm) do que em Coimbra (37,1 cm). Em Coimbra, doenças causadas por Erysiphe polygoni e Ascochita sp. foram moderadas. Em Oratórios, foram feitas três colheitas entre 81 e 94 DAE; em Coimbra, duas: 88 e 100 DAE. As produtividades médias foram de 1093 (Oratórios) e 801 kg/ha (Coimbra). As sementes colhidas em Oratórios apresentaram aspecto ótimo ou bom; em Coimbra, bom ou regular. Concluímos que o plantio do feijão-mungo-verde no inverno, em altitudes entre 400 e 720 m, proporciona produtividades relativamente modestas, especialmente a 720 m, onde as condições climáticas favorecem algumas doenças.

Cold storage of peaches cv. Aurora grown in the Zona da Mata Mineira, Minas Gerais State, Brazil

This study aimed to evaluate the postharvest behavior of peach cv. Aurora 1 harvested in the Zona da Mata region of Minas Gerais in two ripening stages and kept under different storage temperatures. Fruits on mid-ripe and fully ripe stages were stored at three temperatures: 5.6 ± 1.57 °C and 72.8 ± 3.8% RH; 10.4 ± 0.5 °C and 95.8 ± 5.5% RH; 21.04 ± 1.63 °C and 96.9 ± 2.6% RH up to 28 storage days (SD) . During storage, fruits stored at 21.04 ± 1.63 °C were evaluated every two days until 8 SD, and every four days for fruits stored at other temperatures. The harvest day was assigned as day zero. The variables evaluated were CO2 production, color of the pericarp and pulp, fresh mass loss, flesh firmness, total soluble solids, titratable acidity, contents of ascorbic acid and carotenoids. The fresh mass loss increased during storage, peaking at 5.6 °C. The reduction in ascorbic acid content was higher in fully ripe fruits at all temperatures. Mid-ripe fruits reached the end of the storage period with better quality. The temperature of 10.4 °C was the most efficient in keeping postharvest quality of peach cv. Aurora 1 harvested in the Zona da Mata region.

Decomposition of ground biomass of secondary forest and yield of annual crops in no tillage

ABSTRACT The objective of this work was to evaluate the dynamics of decomposition process of chopped secondary forest system, previously enriched with legumes Inga velutina Willd. and Stryphnodendron pulcherrimum (Willd.) Hochr. and the contribution of this process to the nutrient input to the cultivation of corn and bean under no-tillage. The experimental design was a randomized block, split plot with four replications. The plots were two species (I. velutina and S. pulcherrimum) and the subplots were seven times of evaluation (0, 7, 28, 63, 189, 252, 294 days after experiment installation). There was no difference (p ≥ 0.05) between the secondary forest systems enriched and no interaction with times for biomass waste, decomposition constant and half-life time. The waste of S. pulcherrimum trees had higher (p < 0.05) C/N ratio than that I. velutina. However, this one was higher (p < 0.05) in lignin content. Nevertheless, the dynamics of residue decomposition was similar. The corn yield was higher (p < 0.05) in cultivation under I.velutina waste. Meanwhile, the beans planted after corn, shows similar (p > 0.05) yield in both areas, regardless of the waste origin.