Publications by authors named "Motoko Iwashita"

Background: Social affinity and collective behavior are nearly ubiquitous in the animal kingdom, but many lineages feature evolutionarily asocial species. These solitary species may have evolved to conserve energy in food-sparse environments. However, the mechanism by which metabolic shifts regulate social affinity is not well investigated.

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Background: Laterality in relation to behavior and sensory systems is found commonly in a variety of animal taxa. Despite the advantages conferred by laterality (e.g.

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Social behavior is a hallmark of complex animal systems; however, some species appear to have secondarily lost this social ability. In these non-social species, whether social abilities are permanently lost or suppressed is unclear. The blind cavefish is known to be asocial.

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Cave-dwelling animals have evolved a series of morphological and behavioral traits to adapt to their perpetually dark and food-sparse environments. Among these traits, foraging behavior is one of the useful windows into functional advantages of behavioral trait evolution. Presented herein are updated methods for analyzing vibration attraction behavior (VAB: an adaptive foraging behavior) and imaging of associated mechanosensors of cave-adapted tetra, Astyanax mexicanus.

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Dopamine is critical for higher neural processes and modifying the activity of the prefrontal cortex (PFC). However, the mechanism of dopamine contribution to the modification of neural representation is unclear. Using in vivo two-photon population Ca(2+) imaging in awake mice, this study investigated how neural representation of visual input to PFC neurons is regulated by dopamine.

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It is more than fifty years since Alan Turing first presented the reaction-diffusion (RD) model, to account for the mechanism of biological pattern formation. In the paper entitled "The chemical basis of morphogenesis", Turing concluded that spatial patterns autonomously made in the embryo are generated as the stationary wave of the chemical (cellular) reactions. Although this novel idea was paid little attention by experimental biologists, recent experimental data are suggesting that the RD mechanism really functions in some of the course of animal development.

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Many animals have a variety of pigment patterns, even within a species, and these patterns may be one of the driving forces of speciation. Recent molecular genetic studies on zebrafish have revealed that interaction among pigment cells plays a key role in pattern formation, but the mechanism of pattern formation is unclear. The zebrafish jaguar/obelix mutant has broader stripes than wild-type fish.

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Leopard, a well-known zebrafish mutant that has a spotted skin pattern instead of stripes, is a model for the study of pigment patterning. To understand the mechanisms underlying stripe formation, as well as the spot variation observed in leopard, we sought to identify the gene responsible for this phenotype. Using positional cloning, we identified the leopard gene as an orthologue of the mammalian connexin 40 gene.

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Article Synopsis
  • The Polo-like kinase, Plk1, plays a crucial role in regulating mitosis by coordinating the activation of cyclin B-Cdc2 through its interactions with other kinases during meiosis and early embryonic stages in starfish.
  • Contrary to previous beliefs, Plk1 does not serve as the immediate trigger kinase for cyclin B-Cdc2 activation during meiotic reinitiation; rather, it is regulated by distinct upstream kinases specific to each stage of meiosis and early development.
  • Plk1's primary function in activating cyclin B-Cdc2 is linked to its suppression of Myt1, suggesting that Plk1 can be activated by either cyclin A- or cyclin B-Cdc
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