The tetrodotoxin‐resistant (TTX‐R) voltage‐gated sodium channel Nav1.8 is predominantly expressed in peripheral afferent neurons, but in case of neuronal injury an ectopic and detrimental expression of Nav1.8 occurs in neurons of the CNS. In CNS neurons, Nav1.2 and Nav1.6 channels accumulate at the axon initial segment, the site of the generation of the action potential, through a direct interaction with the scaffolding protein ankyrin G (ankG). This interaction is regulated by protein kinase CK2 phosphorylation. In this study, we quantitatively analyzed the interaction between Nav1.8 and ankG. GST pull‐down assay and surface plasmon resonance technology revealed that Nav1.8 strongly and constitutively interacts with ankG, in comparison to what observed for Nav1.2. An ion channel bearing the ankyrin‐binding motif of Nav1.8 displaced the endogenous Nav1 accumulation at the axon initial segment of hippocampal neurons. Finally, Nav1.8 and ankG co‐localized in skin nerves fibers. Altogether, these results indicate that Nav1.8 carries all the information required for its localization at ankG micro‐domains. The constitutive binding of Nav1.8 with ankG could contribute to the pathological aspects of illnesses where Nav1.8 is ectopically expressed in CNS neurons.
In mountain gorillas (Gorilla g. beringei), male immigration in bi-sexual units is rare. This paper presents the case of a nearly weaned male infant gorilla who followed
his mother in her transfer. This case was recorded in the study population at the Kariske Research Center in 1988. The data
come from observation in Group B (on 12 days just prior to the transfer and on 54 days after the transfer over a period of
6 months). The situation of the infant did match the conditions in which infanticide occurs in gorillas, but he was not killed,
despite receiving male aggression and being wounded twice. In fact, both the mother and the infant received male aggression
more frequently than the long term residents in the group. The aggression received by the mother decreased after she mated
with the males and after she weaned the infant. The aggression received by the infant, however, did not decrease after his
mother mated with the males, and increased in intensity. The infant reacted fearfully to male aggression, in marked contrast
to his mother, who reacted either with indifference, or by simply avoiding the males. The aggression eventually stopped, and
the infant became a blackback in Group B. Evolutionarily, the death of the infant would not have markedly accelerated the
mother's return to estrus, but the death of the infant could still have benefitted the males, by decreasing the reproductive
output of a competitor. Adult male gorillas are also presumably selected to resist male immigration. Proximately, the aggression
directed towards the infant was not related to mating access to the mother. The sex of the infant may contribute to explain
the post-transfer male aggression, but data on the integration of old female infants in a new group is needed to test whether
the sex of the infant has an effect on their vulnerability to infanticide. Also, the intense fear displayed by the infant
may have played a role in prompting male aggression. 相似文献
MacArthur and Wilson’s equilibrium theory revolutionized the field of island biogeography and, to a large degree, ecology as well. The theory, which quickly became the ruling paradigm of island biogeography, has changed little over the past three decades. It has not kept pace with relevant theory and our growing appreciation for the complexity of nature, especially with empirical findings that species diversity on many islands: 1) is not in equilibrium; 2) is influenced by differences in speciation, colonization, and extinction among taxa; and 3) is influenced by differences among islands in characteristics other than area and isolation. The discipline of biogeography, itself, is in a state of disequilibrium. We may again be about to witness another paradigm shift, which will see the replacement of MacArthur and Wilson’s theory. Wherever this shift may take us, we are confident that the next generation of biogeographers will still look to islands for insights into the forces that shape biological diversity. 相似文献
MacArthur and Wilson’s equilibrium theory of island biogeography quickly became the paradigm of the field in the 1960s and has strongly influenced this and other disciplines of ecology and conservation biology for the past three decades. Recently, however, a growing number of ecologists have begun to question whether the theory remains a useful paradigm for modern ecology. We now have a much better appreciation for the complexity of nature and we study patterns that span a very broad range in spatial, temporal and ecological scales. At such scales, assumptions that communities are in equilibrium, that species, islands and intervening landscapes or seascapes are equivalent or homogeneous with respect to factors influencing immigration and extinction, and that in situ speciation can be overlooked become very tenuous. With this in mind, this and other papers of this special feature discuss the principal, conceptual shortcomings of the equilibrium theory and offer some modifications or alternatives to the theory that we hope will eventually lead to a more comprehensive understanding of the forces structuring insular communities. 相似文献
