Paternal behavior and testosterone plasma levels in the Volcano Mouse Neotomodon alstoni (Rodentia: Muridae)

Paternal behavior and testosterone plasma levels in the Volcano Mouse Neotomodon alstoni (Rodentia: Muridae). Although initially it was thought that testosterone inhibited the display of paternal behavior in males of rodents, it has been shown that in some species high testosterone levels are needed for exhibition of paternal care. In captivity, males of volcano Mouse (Neotomodon alstoni) provide pups the same care provided by the mother, with the exception of suckling. Here we measured plasmatic testosterone concentrations 10 days after mating, five and 20 days postpartum, and 10 days after males were isolated from their families in order to determine possible changes in this hormone, associated to the presence and age of pups. Males of volcano Mouse exhibited paternal behavior when their testosterone levels were relatively high. Although levels of this hormone did not change with the presence or pups age, males that invested more time in huddling showed higher testosterone levels. It is possible that in the volcano Mouse testosterone modulates paternal behavior indirectly, as in the California mouse. Rev. Biol. Trop. 57 (1-2): 433-439. Epub 2009 June 30.

Aunque inicialmente se pensaba que la testosterona inhibía el despliegue de conducta paterna en los machos de roedores, en algunas especies se ha demostrado que son necesarios niveles altos de testosterona para la exhibición de cuidados paternos. En cautiverio, los machos del ratón mexicano de los volcanes (Neotomodon alstoni), proporcionan a sus crías los mismos cuidados que la madre, con la excepción del amamantamiento. En este estudio se midieron los niveles plasmáticos de testosterona: en el día 10 del apareamiento, 5 y 20 días postparto, y 10 días después de aislar a los machos de sus familias, para establecer si los niveles de esta hormona cambian con relación a la presencia y edad de las crías. El ratón de los volcanes exhibió cuidados paternos cuando sus niveles de testosterona fueron relativamente altos, aunque los niveles de esta hormona no variaron significativamente con relación a la edad y presencia de las crías. Sin embargo, los machos que invirtieron más tiempo en abrigar a las crías, presentaron concentraciones relativamente más altas de testosterona. Es posible que en el ratón de los volcanes la testosterona regule la conducta paterna de manera indirecta, como ocurre con el ratón de California.

Protein-energy malnutrition alters the C3 complement factor in response to lipopolysaccharide in a murine model / A desnutrição proteico-energética altera a concentração do fator C3 do sistema complemento em resposta ao lipopolissacarídeo em um modelo murínico

Malnutrition modifies the hostfis resistance to infection, altering many physiological processes, including hematopoiesis and immunological functions. In this study, we evaluated the total complement system and its C3 component factor in animals subjected to a protein malnutrition model with lipopolysaccharide (LPS) stimulation. The cellularity of blood, bone marrow and spleen, as well as the production of C3 and CH50, were evaluated. Two-month old male Swiss mice were submitted to protein malnutrition with a low-protein diet containing 4% protein. A control group received a control diet containing 20% protein. When the experimental group had reached a loss of about 20% in their original body mass, they were intravenously inoculated with LPS. Cells in the blood, bone marrow and spleen were counted and the circulating levels of C3 and CH50 were evaluated in these animals. Malnourished animals presented anemia, leucopenia, and a severe reduction in bone marrow and spleen cellularity. The survival rate of the malnourished animals was lower, as well as the production of C3 and CH50, if compared to the control animals. These findings suggest that malnourished mice present a deficient response to LPS. The decrease in the complement synthesis may be partially responsible for the immunodeficiency observed. These data lead us to conclude that the nutritional status interferes in the immune response activation.

La desnutrición proteico-energética modifica la resistencia a la infección, alterando numerosos procesos fisiológicos, incluyendo la hematopoyesis y la función inmunológica. En este estudio medimos las concentraciones séricas del factor C3 y del Sistema Complemento Total (CH50) en ratos con desnutrición proteico-energética estimulados con lipopolisacárido (LPS). Fue evaluada la celularidad periférica, medular y esplénica. Ratos Swiss, machos, adultos, con dos meses de edad fueron sometidos a desnutrición proteica con una dieta de 4% de proteína .El grupo control consumía una dieta con 20% de proteínas. Cuando los animales desnutridos perdieron 20% de su peso inicial, fueron inoculados por vía endovenosa con LPS. Fueron determinadas las concentraciones de células sanguíneas, de la médula ósea, del bazo y los valores de C3 y CH50 circulantes en los animales estimulados. Los animales desnutridos presentaron anemia y leucopenia además de una reducción significativa de celularidad de la médula ósea y del bazo. La sobrevivencia de este grupo era menor y también eran más bajas las concentraciones del factor C3 del complemento y del complemento total, en relación a los animales del grupo control. Los resultados sugieren que animales desnutridos muestran una respuesta deficiente a LPS. La síntesis menor de complemento puede ser en parte responsable por la inmunodeficiencia observada. Estos resultados nos conducen a inferir que la desnutrición proteico-energética interfiere en la activación de la respuesta inmune.

A desnutrição proteico-energética modifica a resistência à infecção, modi? cando diversos processos fisiológicos, incluindo a hematopoiese e as funções imunológicas. Neste estudo, avaliamos as concentrações séricas do fator C3 e do Sistema Complemento total (CH50) em um modelo no qual camundongos submetidos à desnutrição proteico-energética são estimulados com lipopolissacarídeo (LPS), e avaliamos a celularidade periférica, medular e esplênica. Camundongos Swiss, machos, adultos, com dois meses de idade foram submetidos ao processo de desnutrição proteica com uma dieta contendo 4% de proteína em comparação aos animais controles com uma dieta contendo 20% de proteína. Quando os animais do grupo desnutrido alcançaram aproximadamente 20% de perda de peso, em relação ao inicial, foram inoculados endovenosamente com LPS. As células do sangue, da medula óssea e do baço foram quantificadas, bem como as concentrações circulantes de C3 e CH50 em animais estimulados com LPS. Os animais desnutridos apresentaram anemia e leucopenia, além de redução significativa da celularidade da medula óssea e do baço. Os animais desnutridos apresentaram menor taxa de sobrevivência, bem como das concentrações do fator C3 do complemento e do complemento total em relação aos animais controles. Estes resultados sugerem que animais desnutridos apresentam uma resposta deficiente aos LPS. A síntese menor do complemento pode ser em parte responsável pela imunodeficiência observada. Estes resultados conduzem-nos a inferir que a desnutrição proteico-energética interfere na ativação da resposta imune.

Characterization of third beta-chain variant in Rattus rattus rufescens.

Different molecular forms of hemoglobins of locally available murines, represented by Rattus rattus rufescens, have been investigated and the probable genetic mechanisms leading to the observed heterogenicity in the hemoglobin phenotypes are discussed. Each fraction was isolated in chromatographically pure form, identified and characterised structurally to establish their alpha- and non-alpha-chain constitution. Six molecular forms of component hemoglobins were identified from a wild population of R. rattus rufescens. The present study suggests five different globin chains in the hemoglobin of house rats (Rattus rattus rufescens). There are apparently two alpha-chains, namely alpha I and alpha II, and three different beta-chains, viz. beta I, beta II and beta III. The invariable presence, though at varying concentrations, of all these five globin chains implicates a gene duplication at the alpha-chain loci and a gene triplication at the beta-chain loci, the latter being a rather rare and unique genetic event.