Yolk: albumen ratio in eggs from laying hens of three genotypes for semi-intensive systems

Se estudió el comportamiento dinámico de la relación yema:albumen en huevos del cruzamiento de tres vías Campero Casilda en comparación con Negra INTA y Rhode Island Red. Se trabajó con muestras aleatorias de 15 huevos de cada grupo genético, extraídas cada cuatro semanas entre las 26 y las 70 semanas de edad. Se calcularon las proporciones de yema y albumen y la relación entre ambas. Los datos de la proporción de yema y de la relación yema:albumen en función de la edad se ajustaron con la función de Brody mientras que para el análisis de los datos correspondientes a la proporción de albumen se utilizó un modelo exponencial decreciente. Los huevos Campero Casilda presentaron similar proporción de yema que Negra INTA en el inicio del ciclo y mayor al finalizar el mismo. Rhode Island Red presentó la menor proporción de yema, la mayor de albumen y la menor relación yema:albumen. La menor proporción de albumen y la mayor relación yema:albumen correspondió a Campero Casilda mientras que Negra INTA presentó valores intermedios de ambos. El mayor contenido de sólidos totales de los huevos de Campero Casilda constituye una ventaja comparativa en términos del valor nutricional, característica de particular trascendencia para la población con necesidades básicas insatisfechas que representa su principal destinataria.The dynamic behaviour of the yolk: albumen ratio was studied in eggs from hens of the three-way cross Campero Casilda compared to Negra INTA and Rhode Island Red. Eggs (n=15) were randomly collected from each genetic group every four weeks between 26 and 70 weeks of age. The proportions of yolk and albumen and the relationship between them were calculated. Yolk proportion and yolk albumen ratio data as a function of age were adjusted with the Brody function and albumen proportion was analyzed using an exponential decay model. Campero Casilda eggs showed a similar proportion of yolk to Negra INTA at the beginning and a higher one at the end of the productive cycle. Rhode Island Red presented the lowest proportion of yolk, the highest proportion of albumen and the lowest yolk: albumen ratio. The lowest albumen proportion and the highest yolk albumen ratio corresponded to Campero Casilda while Negra INTA showed intermediate values of both traits. The higher content of total solids in Campero Casilda eggs constitutes a comparative advantage in terms of nutritional value, a relevant feature when considering the human population with unsatisfied basic needs to which this genotype is particularly destined.Estación Experimental Agropecuaria PergaminoFil: Romera, Bernardo Martín. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Genética; ArgentinaFil: Romera, Bernardo Martín. Programa Estratégico de Formación de Recursos Humanos en Investigación y Desarrollo (PERHID). Becario; ArgentinaFil: Perrotta, Cristian H. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Aves y Pilíferos; ArgentinaFil: Savoy, Juan Pablo. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Aves y Pilíferos; ArgentinaFil: Antruejo, Alejandra E. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra de Aves y Pilíferos; ArgentinaFil: Canet, Zulma Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Sección Avicultura; Argentina.Fil: Canet, Zulma Edith. Universidad Nacional de Rosario. Facultad de Ciencias Veterinaria. Cátedra de Genética; ArgentinaFil: Dottavio, Ana María. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias. Cátedra Genética; Argentina.Fil: Di Masso, Ricardo José. Universidad Nacional de Rosario. Facultad de Ciencias Veterinaria. Cátedra de Genética; Argentina

The interaction of mammalian mitochondrial translational initiation factor 3 with ribosomes: evolution of terminal extensions in IF3mt

Mammalian mitochondrial initiation factor 3 (IF3mt) has a central region with homology to bacterial IF3. This homology region is preceded by an N-terminal extension and followed by a C-terminal extension. The role of these extensions on the binding of IF3mt to mitochondrial small ribosomal subunits (28S) was studied using derivatives in which the extensions had been deleted. The Kd for the binding of IF3mt to 28S subunits is ∼30 nM. Removal of either the N- or C-terminal extension has almost no effect on this value. IF3mt has very weak interactions with the large subunit of the mitochondrial ribosome (39S) (Kd = 1.5 μM). However, deletion of the extensions results in derivatives with significant affinity for 39S subunits (Kd = 0.12−0.25 μM). IF3mt does not bind 55S monosomes, while the deletion derivative binds slightly to these particles. IF3mt is very effective in dissociating 55S ribosomes. Removal of the N-terminal extension has little effect on this activity. However, removal of the C-terminal extension leads to a complex dissociation pattern due to the high affinity of this derivative for 39S subunits. These data suggest that the extensions have evolved to ensure the proper dissociation of IF3mt from the 28S subunits upon 39S subunit joining

New insight in the uranium valence state determination in Uy_yNd1−y_{1−y}O2±x_{2 \pm x}

International audienceThe charge compensation mechanisms in U$_y$Nd$_{1−y}$O$_{2 \pm x}$ and its consequence on the overall O stoichi-ometry (or O/M ratio where M = Nd + U) have been studied through the uranium valence state mixture evolution as a function of Nd content up to y = 0.62 by means of high energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD-XAS) at the U M$_4$-edge. Our results clearly demonstrate the formation of U$^{5+}$ at low Nd content (y < 0.15). Upon increasing the Nd content, oxygen vacancies and the formation of U$^{6+}$ appear as competing mechanisms for intermediate Nd concentrations, leading to the coexistence of U$^{4+}$/U$^{5+}$/U$^{6+}$ mixed valence and an overall hypostoichiometry (O/M < 2.00). Finally, the formation of U 6þ associated with strongly distorted U local environment is observed for high Nd concentrations (y = 0.62), leading to an overall hyperstoichiometry (O/M < 2.00)