Role of Membrane GM1 on Early Neuronal Membrane Actions of Aβ During Onset of Alzheimer\u27s Disease

The ability of beta-amyloid peptide (Aβ) to disrupt the plasma membrane through formation of pores and membrane breakage has been previously described. However, the molecular determinants for these effects are largely unknown. In this study, we examined if the association and subsequent membrane perforation induced by Aβ was dependent on GM1levels. Pretreatment of hippocampal neurons with D-PDMP decreased GM1 and Aβ clustering at the membrane (Aβ fluorescent-punctas/20 μm, control = 16.2 ± 1.1 vs. D-PDMP = 6.4 ± 0.4, p \u3c 0.001). Interestingly, membrane perforation with Aβ occurred with a slower time course when the GM1 content was diminished (time to establish perforated configuration (TEPC) (min): control = 7.8 ± 2 vs. low GM1 = 12.1 ± 0.5, p \u3c 0.01), suggesting that the presence of GM1 in the membrane can modulate the distribution and the membrane perforation by Aβ. On the other hand, increasing GM1 facilitated the membrane perforation (TEPC: control = 7.8 ± 2 vs. GM1 = 6.2 ± 1 min, p \u3c 0.05). Additionally, using Cholera Toxin Subunit-B (CTB) to block the interaction of Aβ with GM1 attenuated membrane perforation significantly. Furthermore, pretreatment with CTB decreased the membrane association of Aβ (fluorescent-punctas/20 μm, Aβ: control = 14.8 ± 2.5 vs. CTB = 8 ± 1.4, p \u3c 0.05), suggesting that GM1 also plays a role in both association of Aβ with the membrane and in perforation. In addition, blockade of the Aβ association with CTB inhibited synaptotoxicity. Taken together, our results strongly suggest that membrane lipid composition can affect the ability of Aβ to associate and subsequently perforate the plasma membrane thereby modulating its neurotoxicity in hippocampal neurons

Preferencias hacia carne de cordero en supermercados de Temuco, región de la Araucanía, Chile

Lobos, G (Lobos, German). Univ Talca, Escuela Ingn Comercial, Talca, ChileThe low levels of consumption of lamb meat in Chile suggest the need for studies on consumer preferences in order to orient production. A study with this object was carried out to evaluate preferences for various cuts, breeds, state (fresh or frozen) and price of lamb's meat among supermarket buyers in Temuco, Chile, and the existence of different market segments, through a survey of 400 persons. Using a fractional factorial design for conjoint analysis, it was determined that the state of the meat was more important than the cut, the price and the breed, with a preference for meat in half carcasses and quarters, Araucano lamb, fresh, at a medium price level. Four consumer segments were distinguished by analysis of hierarchic conglomerates. The majority group (47.7%) was sensitive to the state and the cut, with preference for meat in quarters, fresh, Texel breed. The second group (25.3%) was sensitive to the breed, presenting the strongest preferences for meat in whole carcass, fresh, Araucano lamb. The third group (14.3%) was sensitive to the price, preferred meat in quarters, fresh, Araucano lamb. The minority group (12.7%) was sensitive to the state and price, preferring meat in quarters, Texel breed, and was the only group which preferred frozen meat and would pay a higher price. The segments were distinguished by age, ethnic origin and satisfaction with food-related life. Thus the commercialisation strategy for lamb in supermarkets in Temuco should concentrate principally on the sale of fresh meat cut in quarter

Influência do tipo de levedura e do uso de enzima pectolítica sobre a qualidade de vinhos tintos tropicais cv. Petit verdot.

Existem leveduras com atividades metabólicas variáveis, que permitem a elaboração de vinhos com características sensoriais diferentes. A região do Vale do Submédio São Francisco vem produzindo vinhos há 20 anos, mas está ainda em busca de cultivares que sejam representativas e que possibilitem a obtenção de vinhos potenciais com qualidade e tipicidade. O objetivo deste trabalho foi avaliar a influência do tipo de levedura e do uso de enzima pectolítica, em três condições, sobre a qualidade de vinhos da cv. Petit Verdot. As plantas foram instaladas em fevereiro de 2005, enxertadas sobre o porta-enxerto R110, sistema de condução em espaldeira, solo arenoso, irrigadas por gotejamento. As uvas foram colhidas em julho/2007, apresentando sólidos solúveis totais de 24,5 (ºBrix), acidez total titulável (ATT) de 8 g.L-1 em ácido tartárico, pH 3,5 e peso médio de 100 bagas de 97,6 g. A vinificação foi realizada em frascos de vidro de 20 L, utilizando-se 15 Kg de uvas para cada tratamento. As cinco leveduras testadas foram PDM, Ever rouge e Ever cru, Fermol rouge e Fermol cru. Para cada levedura, foram realizados três tratamentos: sem adição de enzima pectolítica (25 ºC, a temperatura de fermentação), com enzima adicionada a frio (10 ºC durante 24 h) para a maceração pré-fermentação, e enzima adicionada a 25 ºC, totalizando quinze tratamentos. Após a fermentação malolática, os vinhos foram analisados, apresentando variações no teor de álcool (entre 14,2 e 15 % v/v), ATT (entre 4,4 e 7,7), pH (entre 3,9 e 4,3) e índice de polifenóis totais, IPT (entre 89,7 e 101,6). A escolha do tipo de levedura e o uso de enzimas é fundamental para a obtenção de vinhos com diferentes estilos, principalmente nas condições do Vale do São Francisco, onde se busca ainda conhecer o potencial de diferentes cultivares às condições edafo-climáticas locais

Late recurrence of myopic foveoschisis after successful repair with primary vitrectomy and incomplete membrane peeling

PURPOSE: To report three cases of late recurrence of myopic foveoschisis (MF) after initial successful repair with pars plana vitrectomy and membrane peeling to assess the importance of internal limiting membrane peeling. METHODS: A retrospective noncomparative case series was performed of patients who underwent a primary pars plana vitrectomy by a single surgeon with successful resolution of MF, but eventually underwent repeat pars plana vitrectomy for recurrent MF. Best-corrected visual acuity, fundus photography, and optical coherence tomography were obtained at each examination. RESULTS: Three eyes of three patients underwent pars plana vitrectomy for recurrent MF. Myopic foveoschisis recurrence occurred 6, 3.5, and 12 years after the primary vitrectomy, respectively. Repeat vitrectomy with staining and additional peeling of the internal limiting membrane resulted in good anatomical outcome and stabilization of visual acuity in all cases. CONCLUSION: Late recurrence of MF after successful primary vitrectomy is described. Fibrocellular proliferation on residual cortical vitreous or incomplete internal limiting membrane peeling during the initial vitrectomy may underlie recurrence

estMOI: estimating multiplicity of infection using parasite deep sequencing data.

Individuals living in endemic areas generally harbour multiple parasite strains. Multiplicity of infection (MOI) can be an indicator of immune status and transmission intensity. It has a potentially confounding effect on a number of population genetic analyses, which often assume isolates are clonal. Polymerase chain reaction-based approaches to estimate MOI can lack sensitivity. For example, in the human malaria parasite Plasmodium falciparum, genotyping of the merozoite surface protein (MSP1/2) genes is a standard method for assessing MOI, despite the apparent problem of underestimation. The availability of deep coverage data from massively parallizable sequencing technologies means that MOI can be detected genome wide by considering the abundance of heterozygous genotypes. Here, we present a method to estimate MOI, which considers unique combinations of polymorphisms from sequence reads. The method is implemented within the estMOI software. When applied to clinical P.falciparum isolates from three continents, we find that multiple infections are common, especially in regions with high transmission

Estilos de vida en relación a la alimentación y hábitos alimentarios dentro y

Lobos, G (Lobos, German). Univ Talca, Fac Ciencias Empresariales, Escuela Ingn Comercial, Talca, ChileResumen Objetivo: Distinguir tipologías de consumidores en base a su estilo de vida en relación a la alimentación en las principales comunas de la Región Metropolitana de Santiago, Chile, y caracterizarlas según sus hábitos de consumo de alimentos dentro y fuera del hogar, características sociodemográficas y su nivel de satisfacción con su alimentación. Material y método: Se aplicó un cuestionario estructurado a una muestra de 951 personas en las principales comunas de la Región Metropolitana de Santiago (más de 100.000 habitantes). El instrumento de recogida de información incluyó una adaptación del cuestionario de estilos de vida en relación a la alimentación (FRL) y la escala SWFL (Satisfaction with Food-related Life). Se consultaron los hábitos de consumo de alimentos dentro y fuera del hogar y variables de clasificación sociodemográfica de los encuestados. Resultados: Mediante análisis cluster se distinguieron cinco tipologías con diferencias significativas en los cinco componentes obtenidos del FRL, con análisis factorial de componentes principales. Las tipologías presentaron distinto perfil de género, edad y nivel socioeconómico y difirieron en los puntajes obtenidos en la SWFL. Se diferenciaron en la frecuencia en que la persona almuerza, toma once y cena en su hogar. Respecto a las comidas fuera del hogar, las tipologías se distinguieron según la frecuencia de comidas en restaurantes, locales de comida rápida y en la compra de comida preparada. Conclusiones: Un estilo de vida en relación a la alimentación con baja implicación y disfrute de los alimentos se asocia con un mayor nivel socioeconómico y menor edad de las personas. Adicionalmente, se asocia con comportamientos alimentarios poco saludables y no beneficiosos para las personas, como una mayor frecuencia de comidas en restaurantes y de compra de comida preparada, junto a una menor frecuencia de comidas en el hogar, lo que estaría influyendo en un nivel inferior de satisfacción con la alimentación

Synaptotoxicity of Alzheimer Beta Amyloid Can Be Explained by Its Membrane Perforating Property

The mechanisms that induce Alzheimer's disease (AD) are largely unknown thereby deterring the development of disease-modifying therapies. One working hypothesis of AD is that Aβ excess disrupts membranes causing pore formation leading to alterations in ionic homeostasis. However, it is largely unknown if this also occurs in native brain neuronal membranes. Here we show that similar to other pore forming toxins, Aβ induces perforation of neuronal membranes causing an increase in membrane conductance, intracellular calcium and ethidium bromide influx. These data reveal that the target of Aβ is not another membrane protein, but that Aβ itself is the cellular target thereby explaining the failure of current therapies to interfere with the course of AD. We propose that this novel effect of Aβ could be useful for the discovery of anti AD drugs capable of blocking these “Aβ perforates”. In addition, we demonstrate that peptides that block Aβ neurotoxicity also slow or prevent the membrane-perforating action of Aβ

Surface plasmon resonance biosensors for highly sensitive detection in real samples

In this work we summarize the main results obtained with the portable surface plasmon resonance (SPR) device developed in our group (commercialised by SENSIA, SL, Spain), highlighting its applicability for the real-time detection of extremely low concentrations of toxic pesticides in environmental water samples. In addition, we show applications in clinical diagnosis as, on the one hand, the real-time and label-free detection of DNA hybridization and single point mutations at the gene BRCA-1, related to the predisposition in women to develop an inherited breast cancer and, on the other hand, the analysis of protein biomarkers in biological samples (urine, serum) for early detection of diseases. Despite the large number of applications already proven, the SPR technology has two main drawbacks: (i) not enough sensitivity for some specific applications (where pM-fM or single-molecule detection are needed) (ii) low multiplexing capabilities. In order solve such drawbacks, we work in several alternative configurations as the Magneto-optical Surface Plasmon Resonance sensor (MOSPR) based on a combination of magnetooptical and ferromagnetic materials, to improve the SPR sensitivity, or the Localized Surface Plasmon Resonance (LSPR) based on nanostructures (nanoparticles, nanoholes,...), for higher multiplexing capabilities