2 research outputs found
Dietary dopamine causes ovary activation in queenless Apis mellifera workers
Groups of young honey bee workers were fed a diet containing dopamine while confined in
small cages at 34 °C and 80% RH in absence of a queen for 8 to 13 days. The bees in
eight pairs of cages, each pair containing an equal number of workers, received a
pollen-rich diet supplemented with dopamine (10 g/g of diet) (DOP groups), or not
supplemented (controls). The rate of consumption of the diet was monitored continuously
during the confinement period, after which the workers were dissected to assess
follicle development in the ovaries. The results showed a significantly higher
proportion () of workers with activated ovaries in the DOP groups than in
control groups. The number of bees surviving confinement was significantly higher
in the control groups than in the DOP groups (), possibly reflecting a
deleterious effect of dopamine. The surviving bees from both groups consumed equivalent
amounts of diet (), showing that ovary activation was not due to differential
diet consumption. The results suggest a role of dopamine in the chain of events
mediating changes in the reproductive status of orphan honey bee workers
Myosin Va is developmentally regulated and expressed in the human cerebellum from birth to old age
Myosin Va functions as a processive, actin-based motor molecule highly enriched in the nervous system, which transports and/or tethers organelles, vesicles, and mRNA and protein translation machinery. Mutation of myosin Va leads to Griscelli disease that is associated with severe neurological deficits and a short life span. Despite playing a critical role in development, the expression of myosin Va in the central nervous system throughout the human life span has not been reported. To address this issue, the cerebellar expression of myosin Va from newborns to elderly humans was studied by immunohistochemistry using an affinity-purified anti-myosin Va antibody. Myosin Va was expressed at all ages from the 10th postnatal day to the 98th year of life, in molecular, Purkinje and granular cerebellar layers. Cerebellar myosin Va expression did not differ essentially in localization or intensity from childhood to old age, except during the postnatal developmental period. Structures resembling granules and climbing fibers in Purkinje cells were deeply stained. In dentate neurons, long processes were deeply stained by anti-myosin Va, as were punctate nuclear structures. During the first postnatal year, myosin Va was differentially expressed in the external granular layer (EGL). In the EGL, proliferating prospective granule cells were not stained by anti-myosin Va antibody. In contrast, premigratory granule cells in the EGL stained moderately. Granule cells exhibiting a migratory profile in the molecular layer were also moderately stained. In conclusion, neuronal myosin Va is developmentally regulated, and appears to be required for cerebellar function from early postnatal life to senescence