Reconstruction of the migratory history of the catadromous fourspine sculpin Cottus kazika from the Monobe and Shimanto River, Kochi prefecture in southern Shikoku, using otolith Sr/Ca concentration ratios

カマキリ当歳魚の遡上履歴を推定する目的で，耳石輪紋の日周性ならびに耳石Sr/Ca比と塩分濃度との関係について調べた。その結果，本種の耳石輪紋は日周輪であること，および耳石Sr/Ca比は海水中で顕著に上昇することを確認した。これらの結果をもとに，高知県四万十川および物部川で採集したカマキリ当歳魚の遡上時期を推定したところ，海水から淡水への移行期は，いずれの河川においても3月上旬と推定された。The fourspine sculpin (Cottus kazika) is a catadromous member of the family Cottidae that is endemic to Japan. Our objective was to evaluate the utility of using sagittal otolith Sr/Ca concentration ratios to document the movement of juvenile sculpin between the estuarine areas and freshwater of the Shimanto and Monobe Rivers in southern Shikoku. We confirmed the daily periodicity of increment formation and the correlation between the otolith Sr/Ca ratio and ambient salinity at laboratory condition. Otolith profiles suggested that juveniles tended to move from seawater to freshwater at the beginning of March in both river systems

Study of Togo -Matsuzaki Hot Springs, Tottori Prefecture

1. Layers containing thermal water in this district are thin, and lie at different depths (about 35, 55, and 60 meters) from the ground surface. There are evidences to show that these layers are intimately connected with one another. 2. The authors may suppose the existence of a structurally weak zone, along the line from Matsuzaki to Asozu, within which the issuing spots of thermal springs are located. 3. The head water levels of the thermal springs in this district are closely related with that of Lake Togo. Keeping pace with the variations of the water levels of Lake Togo and of artesian wells in its vicinity, the rate of flow of thermal springs vary; and the correlation between these variations is apparent. 4. The pumping suction of thermal water at one spring affects the flow of water at other springs within distances of 150 to 200 meters therefrom, though the direct sources of thermal water supply for the latter springs may be different from that of the former. 5. The spring water in this district is considered to be a mixture of hot water, containing sodium, calcium, chloride, and sulfate ions, and cold water, containing bicarbonate ion. The diversity of chemical constitutions of different spring waters is explained as due to the difference in proportion in which the hot and cold waters are mixed

An Angiotensin II Type 1 Receptor Blocker Prevents Renal Injury via Inhibition of the Notch Pathway in Ins2 Akita Diabetic Mice

Recently, it has been reported that the Notch pathway is involved in the pathogenesis of diabetic nephropathy. In this study, we investigated the activation of the Notch pathway in Ins2 Akita diabetic mouse (Akita mouse) and the effects of telmisartan, an angiotensin II type1 receptor blocker, on the Notch pathway. The intracellular domain of Notch1 (ICN1) is proteolytically cleaved from the cell plasma membrane in the course of Notch activation. The expression of ICN1 and its ligand, Jagged1, were increased in the glomeruli of Akita mice, especially in the podocytes. Administration of telmisartan significantly ameliorated the expression of ICN1 and Jagged1. Telmisartan inhibited the angiotensin II-induced increased expression of transforming growth factor β and vascular endothelial growth factor A which could directly activate the Notch signaling pathway in cultured podocytes. Our results indicate that the telmisartan prevents diabetic nephropathy through the inhibition of the Notch pathway

Role of PERK in mitochondrial function

Mitochondria play a central role in the function of brown adipocytes (BAs). Although mitochondrial biogenesis, which is indispensable for thermogenesis, is regulated by coordination between nuclear DNA transcription and mitochondrial DNA transcription, the molecular mechanisms of mitochondrial development during BA differentiation are largely unknown. Here, we show the importance of the ER-resident sensor PKR-like ER kinase (PERK) in the mitochondrial thermogenesis of brown adipose tissue. During BA differentiation, PERK is physiologically phosphorylated independently of the ER stress. This PERK phosphorylation induces transcriptional activation by GA-binding protein transcription factor α subunit (GABPα), which is required for mitochondrial inner membrane protein biogenesis, and this novel role of PERK is involved in maintaining the body temperatures of mice during cold exposure. Our findings demonstrate that mitochondrial development regulated by the PERK–GABPα axis is indispensable for thermogenesis in brown adipose tissue