A picrotoxin-specific conformational change in the glycine receptor M2-M3 loop.

The external loop linking the M2 and M3 transmembrane domains is crucial for coupling agonist binding to channel gating in the glycine receptor chloride channel (GlyR). A substituted cysteine accessibility scan previously showed that glycine activation increased the surface accessibility of 6 contiguous residues (Arg(271) Lys(276)) toward the N-terminal end of the homomeric alpha 1 GlyR M2 - M3 loop. In the present study we used a similar approach to determine whether the allosteric antagonist, picrotoxin, could impose conformational changes to this domain that cannot be induced by varying agonist concentrations alone. Picrotoxin slowed the reaction rate of a sulfhydryl-containing compound ( MTSET) with A272C, S273C, and L274C. Before interpreting this as a picrotoxin-specific conformational change, it was necessary to eliminate the possibility of steric competition between picrotoxin and MTSET. Accordingly, we showed that picrotoxin and the structurally unrelated blocker, bilobalide, were both trapped in the R271C GlyR in the closed state and that a point mutation to the pore-lining Thr(6') residue abolished inhibition by both compounds. We also demonstrated that the picrotoxin dissociation rate was linearly related to the channel open probability. These observations constitute a strong case for picrotoxin binding in the pore. We thus conclude that the picrotoxin-specific effects on the M2 - M3 loop are mediated allosterically. This suggests that the M2 - M3 loop responds differently to the occupation of different binding sites.

On strongly regular graphs with m2 = qm3 and m3 = qm2

2010 Mathematics Subject Classification: 05C50.

Stomach content records for pelagic fish (herring, mackerel, blue whiting, albacore and bluefin tuna) in the northeast Atlantic

Fish stomach content records extracted from the DAPSTOM 4.5 database (held at the UK Centre for Environment, Fisheries and Aquaculture Science - CEFAS). Data collated as part of the EU Euro-Basin project and specifically concerning herring (Clupea harengus), mackerel (Scomber scombrus), blue whiting (Micromesistius poutassou), albacore (Thunnus alalunga) and bluefin tuna (Thunnus thynnus). The data set consist of 20720 records - collected throughout the northeast Atlantic, between 1906 and 2011 - mostly during routine fisheries monitoring research cruises.

Les expositions agricoles et industrielles à Montréal entre 1880 et 1884

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Les expositions agricoles et industrielles à Montréal entre 1880 et 1884

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Queen's College Journal (1883-1884)

The Journal has been Queen's main student newspaper since it was founded in 1873. It appears twice a week on campus with a mix of news, sports, and entertainment stories, editorials, letters to the editor, and photographs. The paper is students' most important source of news and general information and has been a training ground for scores of Canadian journalists.

Queen's College Journal (1884-1885)

The Journal has been Queen's main student newspaper since it was founded in 1873. It appears twice a week on campus with a mix of news, sports, and entertainment stories, editorials, letters to the editor, and photographs. The paper is students' most important source of news and general information and has been a training ground for scores of Canadian journalists.

Peruanos y bolivianos en la sátira chilena de la Guerra del Pacífico (1879 - 1884)

A partir de los grabados publicados en las páginas de los periódicos que incluyeron humor gráfico en sus ediciones durante la Guerra del Pacífico (1879 - 1883), los caricaturistas chilenos desplegaron un discurso visual agresivo en clave patriótica y belicista, donde presentaron a sus lectores una imagen crítica y despectiva respecto de los adversarios de Chile. Recalcaron la supuesta falta de ánimo y valor combativo, ante la sola presencia de los efectivos militares chilenos tanto en el mar como en tierra. Así, la tinta y el papel, se transformaron en otra de las armas que intervinieron en el conflicto de Chile contra el Perú y Bolivia por la posesión de los ricos territorios salitreros de Tarapacá y Antofagasta. Las imágenes fueron interpretadas a partir de los postulados de la Escuela de Warburg, en especial los de Erwin Panofsky, que propone tres niveles de estudio del significado de cada obra, a saber, la “descripción preiconográfica”, luego el “estudio iconográfico” en cuanto tal y, finalmente, la “interpretación iconológica”.