No abstract

Maintenance of the energy balance is indispensable for cell survival and function. Adenylate kinase (Ak) is a ubiquitous enzyme highly conserved among many organisms. Ak plays an essential role in energy regulation by maintaining adenine nucleotide homeostasis in cells. However, its role at the whole organism level, especially in animal behavior, remains unclear. Here, we established a model using medaka fish (Oryzias latipes) to examine the function of Ak in environmental adaptation. Medaka overexpressing the major Ak isoform Ak1 exhibited increased locomotor activity compared to that of the wild type. Interestingly, this increase was temperature dependent. Our findings suggest that cellular energy balance can modulate locomotor activity.

We report here an unusual case of fibrous histiocytoma in which an area of xanthogranuloma was observed histologically. Our case suggests that adult xanthogranuloma is a variant of fibrous histiocytoma.

Maintenance of the energy balance is indispensable for cell survival and function. Adenylate kinase (Ak) is a ubiquitous enzyme highly conserved among many organisms. Ak plays an essential role in energy regulation by maintaining adenine nucleotide homeostasis in cells. However, its role at the whole organism level, especially in animal behavior, remains unclear. Here, we established a model using medaka fish (Oryzias latipes) to examine the function of Ak in environmental adaptation. Medaka overexpressing the major Ak isoform Ak1 exhibited increased locomotor activity compared to that of the wild type. Interestingly, this increase was temperature dependent. Our findings suggest that cellular energy balance can modulate locomotor activity.

Animals living outside the tropics show dynamic seasonal changes in their physiology and behavior. Japanese quail is an excellent model for photoperiodic studies and has been used by our group to reveal the molecular mechanism of seasonal reproduction. Molecular analysis of the quail mediobasal hypothalamus (MBH) helped us to identify several genes critical for seasonal reproduction. Furthermore, comparative studies have uncovered universality and diversity of photoperiodic mechanisms in birds, mammals and fish. We are also interested in seasonal changes in animal behavior. Medaka is an excellent model for these studies on seasonal adaptation because of its clear seasonality. Our recent studies demonstrated that dynamic plasticity in phototransduction regulates seasonal changes in color perception in medaka. Here, we discuss the underlying mechanism of seasonal adaptation in animals.