Salt induced asymmetry in membrane simulations by partial restriction of ionic motion

The specific ionic composition differs considerably at both sides of biological membranes and specific lipid/electrolyte interactions may be essential for their structure, stability and function. Hence, explicit consideration of the ionic asymmetry is important to achieve an accurate description of lipid bilayers. Molecular dynamics simulations have proven to be a reliable tool to study biomembranes at atomic detail. Nevertheless, the use of periodic boundary conditions allows ions to diffuse rapidly and reach both sides of the bilayer. Therefore, ad hoc simulation schemes have to be applied to take into account ionic asymmetry. In this work we present a simple implementation to overcome this problem. A more realistic description of the biomembranes can be achieved by partially restricting the ionic motion in the direction normal to the membrane within a region of the space near to only one of the leaflets. This creates two different situations: one leaflet is highly exposed to ions while the second one can be completely or partially depleted of them. Comparison between this new method and control simulations performed using a previously proposed approach consisting of a double-membrane setup yielded an excellent agreement with a speed-up of nearly 60%. The performance of the method with different ionic species is explored and remaining limitations are examined.Fil: Herrera, Fernando Enrique. Universidad Nacional del Litoral; ArgentinaFil: Pantano Gutierrez, Sergio Fabian. Universidad Nacional de San Luis; Argentin

Augmentative releases of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) for Ceratitis capitata (Diptera: Tephritidae) control in a fruit-growing region of Argentina

Field-open augmentative releases were conducted to assess the efficacy of Diachasmimorpha longicaudata (Ashmead) for the regulation of Ceratitis capitata (Weidemann) infesting Ficus carica (L.) in a commercial area located in a fruit-producing irrigated-valley of San Juan, central-western Argentina. Parasitoids were reared on Sensitive Lethal Temperature Vienna-8 strain of C. capitata at the BioPlanta San Juan facilities, and were weekly released throughout 9 weeks over two experimental plots of ca. 2.3 ha each with a density of 5200 wasps/plot. Host mortality and medfly emergence at the release plots were significantly 1.9-times higher and 1.5-times lower, respectively, than those recorded in the control plots. D. longicaudata females increase their effectiveness on medfly at both higher temperature (22–23 °C) and relative humidity (54–62%) values. Parasitoid females used in the study showed a good ability to spread once released in open-field. Between 16 and 75% of host mortality during the parasitoid release period was due to D. longicaudata, which appears to be promising for the control of medfly in San Juan as well as in other similar Argentinean fruit-growing semi-arid regions.Fil: Sánchez, Guillermo. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Murúa, Fernando. Universidad Nacional de San Juan; Argentina. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Suárez, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Van Nieuwenhove, Guido Alejandro. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Taret, Gustavo Abelardo Ariel. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Pantano, Valeria. Provincia de San Juan. Dirección de Sanidad Vegetal, Animal y Alimentos; ArgentinaFil: Bilbao, Mariana. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Schliserman, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentin

Criopreservação de mórulas de camundongos em glicerol, sacarose e geléia real

Compacted mouse morulae were frozen at 0.3ºC/min. or 0.5ºC/min. from -6ºC to -24ºC or -32ºC in 10% of glycerol plus different sucrose concentrations with or without 0.1% of honeybee royal jelly. Embryos were thawed in water bath at 22ºC for 20 seconds and cryoprotectant dilution was done in three steps. Embryos were cultured in Whittens medium for 24, 48 and 72 hours at 37ºC, 5% of CO2 and 100% of humidity. The in vitro development ranged from 56.6% to 100% after 72 hours. Expanded blastocysts were transferred to pseudopregnant recipients on the third day of the estrous cycle. Viable fetuses rates for embryos frozen to -24 or -32ºC at 0.3ºC/minute in 10% glycerol + 10% sucrose, 10% glycerol + 10% sucrose + 0.1% honeybee royal jelly, 10% glycerol + 0.1% honeybee royal jelly or 10% glycerol were respectively: 28.1% and 13.6%, 48.7% and 31.9%, 28.6% and 13.2%, 20.0% and 42.4%. Viable fetuses for embryos frozen to -24ºC or -32ºC at 0.5ºC/minute in 10% glycerol + 10% sucrose or 10% glycerol + 10% sucrose + 0.1% honeybee royal jelly were respectively 29.0% and 15.3%, 48.8% and 32.0%. We can conclude that addition of 10% sucrose to 10% glycerol was efficient for embryo freezing at 0.3 or 0.5ºC/minute and plunged in liquid nitrogen at -24ºC. The honeybee royal jelly addition provided higher viable fetuses rates when embryos were cooled at 0.3 or 0.5ºC/minute and plunged in liquid nitrogen at -24ºC.Embriões de camundongos foram congelados em 10% de glicerol adicionado de várias concentrações de sacarose e/ou 0,1% de geléia real, nas velocidades de 0,3ºC ou 0,5ºC/minuto até -24ºC ou -32ºC e descongelados em água a 22ºC durante 20 segundos. A diluição dos crioprotetores foi realizada em três etapas e o cultivo dos embriões no meio de Whitten em estufa com 5% de CO2, 100% de umidade e 37ºC por 72 horas. O desenvolvimento in vitro até blastocisto variou entre 56,6% e 93,4%, mostrando que 10% de sacarose + 10% de glicerol foi eficiente na congelação. Blastocistos expandidos oriundos de embriões congelados até -24 ou -32ºC à velocidade de 0,3ºC/minuto em soluções contendo 10% de glicerol + 10% de sacarose; 10% de glicerol + 10% de sacarose + 0,1% de geléia real; 10% de glicerol + 0,1% de geléia real ou 10% de glicerol, transferidos para receptoras pseudoprenhes, apresentaram, respectivamente, taxas de fetos viáveis de 28,1% e 13,6%, 48,7% e 31,9%, 28,6% e 13,2%, 20,0% e 42,4%. Embriões congelados até -24ºC ou -32ºC a 0,5ºC/minuto nas soluções de 10% de glicerol + 10% de sacarose ou 10% de glicerol + 10% de sacarose + 0,1% de geléia real apresentaram, respectivamente, taxas de fetos viáveis de 29,0% e 15,3%, 48,8% e 32,0%. Adição de sacarose e de geléia real ao meio de congelação contendo 10% de glicerol proporcionou maiores taxas de fetos viáveis a 0,3ºC e 0,5ºC/minuto e imersão em nitrogênio líquido a -24ºC

Commentary: p31-43 Gliadin Peptide Forms Oligomers and Induces NLRP3 Inflammasome/Caspase 1- Dependent Mucosal Damage in Small Intestine

In our recent publication p31-43 Gliadin Peptide Forms Oligomers and Induces NLRP3 Inflammasome/Caspase 1- Dependent Mucosal Damage in Small Intestine” (1) we showed by a combination of experimental and simulation techniques that the peptide p31-43 Gliadin has an intrinsic propensity to form oligomers, which trigger the NLRP3 inflammasome, resulting in intestinal inflammation and pathology. In particular, molecular simulations performed with the SIRAH force field (2), showed that isolated p31-43 peptides exhibit a broad conformational dynamic with some PPII component, mostly related to the presence of Pro36 and Pro42. Simulation of multiple replicas showed a spontaneous tendency to aggregation with a concomitant increase in the PPII content for Pro38 and Pro 39.Comentario al artículo p31-43 Gliadin Peptide Forms Oligomers and Induces NLRP3 Inflammasome/Caspase 1- Dependent Mucosal Damage in Small Intestinepor Gómez Castro, M. F., Miculán, E., Herrera, M. G., Ruera, C., Perez, F., Prieto, E. D., et al. (2019). Front. Immunol. 10:31. doi: 10.3389/fimmu.2019.00031Instituto de Estudios Inmunológicos y Fisiopatológico

Efeitos do crioprotetor e da temperatura de imersão em nitrogênio líquido sobre o desenvolvimento in vivo e in vitro de mórulas de camundongos

Os efeitos das temperaturas de imersão em nitrogênio líquido e dos métodos de remoção dos crioprotetores foram avaliados em mórulas de camundongos congeladas em etilenoglicol (E), propilenoglicol (P) e glicerol (G). Os embriões foram equilibrados em E (1,5M), P (1,5M) ou G (1,4M) por 10 minutos e envasados em palhetas de 0,25 ml com crioprotetor nas três colunas (E1, P1 G1) ou PBS nas colunas das extremidades (E2, P2). As palhetas foram resfriadas a 0,5ºC/minuto até -25 ou -30ºC e imersas em nitrogênio líquido. A descongelação dos embriões foi feita em água a 22ºC por 20 segundos. O crioprotetor dos embriões congelados em glicerol (Gl) foi removido em 3 etapas, dos congelados em etilenoglicol e propilenoglicol com crioprotetor nas 3 colunas (El e Pl) removido diretamente em PBS e dos congelados em etilenoglicol e propilenoglicol com PBS nas colunas das extremidades (E2, P2), após mistura das três colunas dentro da palheta, em PBS. Não houve influência da temperatura de imersão sobre o desenvolvimento embrionário in vitro, observando maior taxa (p < 0,0001) para El (69,2%) que para E2 (60,3%), Gl (51,9%) e a combinação P1 e P2 (46,9%). Para o desenvolvimento in vivo, a taxa de fetos foi menor (p < 0,07) para o grupo E1-25 do que para o Controle; Gl-30ºC; El-30ºC e E2-25ºC. Pode-se concluir que in vitro o melhor crioprotetor foi o etilenoglicol com remoção direta em PBS e que in vivo o etilenoglicol e o glicerol foram semelhantes a -30ºC.The effects of plunging temperature in liquid nitrogen and cryoprotectant dilution methods were evaluated for compacted mouse morulae frozen in 1.5 M ethylene-glycol (E), 1.5M propylene-glycol (P) or 1.4M glycerol (G). Morulae were equilibrated for 10 minutes in cryoprotectant solution and loaded into 0.25 ml straws with cryoprotectant solution in 3 columns (groups E1, P1, G1) or cryoprotectant in the center and PBS in the lateral columns (E2, P2). Straws were cooled at 0.5ºC/min to -25 or -30ºC and plunged into liquid nitrogen. Straws were thawed in water at 22ºC for 20 seconds. Cryoprotectant was diluted in 3 steps for group G1 and in one step for groups E1 and P1 (direct transfer to PBS + 10% FCS) and E2 and P2 (shaken to mix the 3 columns before transferring to PBS+ 10% FCS). Plunging temperature had no significant effect on the proportion of morulae developed to blastocysts in vitro; this proportion was higher (p < 0.0001) in E1 (69.2%) than in E2 (60.3%), G1 (51.9%) and combined for P1 and P2 (46.9%). In second experiment, the proportion of transferred morulae that developed to viable fetuses was lower (p < 0.07) for E1-25 than for E1-30, G1-30, E2-25 or unfrozen (control) embryos (8.7, 20.0, 20.0, 17.4 and 19.8%, respectively). In conclusion, the ethylene glycol diluted directly in PBS (E1) exhibit the highest rate of in vitro embryos development, but based on in vivo embryos development was more efficacious in plunging temperature at -30ºC (E1-30)

Structural conformation and self‐assembly process of p31‐43 gliadin peptide in aqueous solution. Implications for celiac disease

Celiac Disease (CeD) is a highly prevalent chronic immune-mediated enteropathy developed in genetically predisposed individuals after ingestion of a group of wheat proteins (called gliadins and glutenins). The 13mer α-gliadin peptide, p31-43, induces proinflammatory responses, observed by in vitro assays and animal models, that may contribute to innate immune mechanisms of CeD pathogenesis. Since a cellular receptor for p31-43 has not been identified, this raises the question of whether this peptide could mediate different biological effects. In this work, we aimed to characterize the p31-43 secondary structure by different biophysical and in silico techniques. By Dynamic Light Scattering (DLS) and using an oligomer/fibril-sensitive fluorescent probe, we showed the presence of oligomers of this peptide in solution. Furthermore, Atomic Force Microscopy (AFM) analysis showed p31-43 oligomers with different height distribution. Also, peptide concentration had a very strong influence on peptide self-organization process. Oligomers gradually increased their size at lower concentration. Whereas, at higher ones, oligomers increased their complexity, forming branched structures. By Circular Dichroism, we observed that p31-43 self-organized in a poly-proline II conformation in equilibrium with βsheets-like structures, whose pH remained stable in the range of 3 to 8. In addition, these findings were supported by Molecular Dynamics Simulation. The formation of p31-43 nanostructures with increased β-sheet structure may help to explain the molecular etiopathogenesis in the induction of pro-inflammatory effects and subsequent damage at the intestinal mucosa in CeD.Fil: Herrera, Maria Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Gomez Castro, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Estudios Inmunológicos y Fisiopatológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios Inmunológicos y Fisiopatológicos; ArgentinaFil: Prieto, Eduardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Barrera Guisasola, Exequiel Ernesto. Instituto Pasteur de Montevideo; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dodero, Veronica Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universitat Bielefeld; AlemaniaFil: Pantano Gutierrez, Sergio Fabian. Instituto Pasteur de Montevideo; UruguayFil: Chirdo, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Estudios Inmunológicos y Fisiopatológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios Inmunológicos y Fisiopatológicos; Argentin

p31-43 Gliadin Peptide Forms Oligomers and Induces NLRP3 Inflammasome/Caspase 1- Dependent Mucosal Damage in Small Intestine

Celiac disease (CD) is a chronic enteropathy elicited by a Th1 response to gluten peptides in the small intestine of genetically susceptible individuals. However, it remains unclear what drives the induction of inflammatory responses of this kind against harmless antigens in food. In a recent work, we have shown that the p31-43 peptide (p31-43) from α-gliadin can induce an innate immune response in the intestine and that this may initiate pathological adaptive immunity. The receptors and mechanisms responsible for the induction of innate immunity by p31-43 are unknown and here we present evidence that this may reflect conformational changes in the peptide that allow it to activate the NLRP3 inflammasome. Administration of p31-43, but not scrambled or inverted peptides, to normal mice induced enteropathy in the proximal small intestine, associated with increased production of type I interferon and mature IL-1β. P31-43 showed a sequence-specific spontaneous ability to form structured oligomers and aggregates in vitro and induced activation of the ASC speck complex. In parallel, the enteropathy induced by p31-43 in vivo did not occur in the absence of NLRP3 or caspase 1 and was inhibited by administration of the caspase 1 inhibitor Ac-YVAD-cmk. Collectively, these findings show that p31-43 gliadin has an intrinsic propensity to form oligomers which trigger the NLRP3 inflammasome and that this pathway is required for intestinal inflammation and pathology when p31-43 is administered orally to mice. This innate activation of the inflammasome may have important implications in the initial stages of CD pathogenesis.Instituto de Estudios Inmunológicos y Fisiopatológico

Control Biológico de Moscas de la Fruta en Argentina: Experiencias de Evaluación de Parasitoides contra Ceratitis capitata y Anastrepha fraterculus (Diptera: Tephritidae) en Distintas Regiones Frutihortícolas

Anastrepha fraterculus y Ceratitis capitata son actualmente importantes plagas de la frutihorticultura argentina. En consecuencia, el control biológico está siendo considerado como un componente clave en las estrategias de manejo de estas dos especies de tefrítidos plagas en distintas regiones agrícolas. Por tal motivo, se realizaron evaluaciones de parasitoides como agentes de biocontrol en la región citrícola del noroeste (subtrópico) y en la región vitivinícola del centro-oeste argentino (desértico continental). El bracónido exótico Diachasmimorpha longicaudata, un endoparasitoide de larvas, y el diaprido nativo Coptera haywardi, un endoparasitoide de pupas, fueron evaluados en condiciones ambientales naturales usando jaulas de campo en la provincia de Tucumán (noroeste). Se partió de la premisa que el uso combinado de ambos parasitoides sería más eficiente para suprimir a A. fraterculus que el uso individual de las especies. Mientras se utilizaron individualmente, la efectividad de D. longicaudata y C. haywardi fue de 75% y 56%, respectivamente. Sin embargo, la eficacia total se incrementó en un 93% cuando se usaron secuencialmente. Asimismo, la eficacia de D. longicaudata para suprimir a C. capitata fue evaluada mediante liberaciones aumentativas del parasitoide en un área productora de higos localizada en un valle frutícola de la provincia de San Juan (centro oeste). Los parasitoides fueron criados masivamente en la BioPlanta San Juan usando larvas de C. capitata de la cepa tsl Vienna-8. Las liberaciones se realizaron durante 9 semanas a una densidad aproximada de 1.200 adultos/ha. La mortalidad de la plaga y la emergencia de C. capitata en las parcelas de liberación fue 3 veces más alta y 2 veces más baja, respectivamente, que aquellas registradas en las parcelas testigos. Según los resultados, el control biológico sería una herramienta válida y complementaria dentro de las estrategias bioracionales de control de moscas de la fruta en Argentina.Fil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Van Nieuwenhove, Guido Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Bezdjian, Laura Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Sánchez, Guillermo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Murúa, Fernando. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Suárez, Lorena. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Schliserman, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Bilbao, Mariana. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Pantano, Valeria. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Taret, Gustavo. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaXXVI Congresso Brasileiro de Entomología y IX Congreso Latinoamericano de EntomologíaMaceio, AlagoasBrasilSociedade Brasilera de Entomologi

Structure and dynamics of nano-sized raft-like domains on the plasma membrane

Cell membranes are constitutively composed of thousands of different lipidic species, whose specific organization leads to functional heterogeneities. In particular, sphingolipids, cholesterol and some proteins associate among them to form stable nanoscale domains involved in recognition, signaling, membrane trafficking, etc. Atomic-detail information in the nanometersecond scale is still elusive to experimental techniques. In this context, molecular simulations on membrane systems have provided useful insights contributing to bridge this gap. Here we present the results of a series of simulations of biomembranes representing non-raft and raft-like nano-sized domains in order to analyze the particular structural and dynamical properties of these domains. Our results indicate that the smallest (5 nm) raft domains are able to preserve their distinctive structural and dynamical features, such as an increased thickness, higher ordering, lower lateral diffusion, and specific lipid-ion interactions. The insertion of a transmembrane protein helix into non-raft, extended raft-like, and raft-like nanodomain environments result in markedly different protein orientations, highlighting the interplay between the lipid-lipid and lipid-protein interactions. © 2012 American Institute of Physics.Fil: Herrera, Fernando Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Institut Pasteur de Montevideo; Uruguay. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; ArgentinaFil: Pantano Gutierrez, Sergio Fabian. Institut Pasteur de Montevideo; Urugua