Corpuscles of Stannius of freshwater catfish, Clarias Batrachus

O presente artigo estuda o número, localização e estrutura citológica dos corpúsculos de Stannius do bagre de água doce Clarias batrachus. Ocorre apenas um tipo celular e as células são eosina +, AF + e PAS +

Ultimobranchial body of freshwater catfish Heteropneustes fossilis

0 presente estudo refere-se aos detalhes do corpo utimobranquial de Heteropneustes fossilis. A glândula está localizada no intersepto entre as cavidades pericárdicas e abdominais. A glândula geralmente consiste de um parênquimasólido o qual é composto de cordões celulares. Algumas vezes, foram vistos também folículos

Parathyroid gland of the frog Rana tigrina

A glândula paratiróide de Rana tigrina é composta por células epiteliais densamente agrupadas que são distribuídas em círculos. A diferença na densidade das células paratiroidais já foi registrada. As células no centro da glândula são compactamente agrupadas possuindo núcleos alongados e citoplasma denso. As células da periferia da glândula são dsitribuídas frouxamente, tendo citoplasma claramente corado e núcleos esféricos grandes

Increased prostaglandin e2 has a positive correlation with plasma calcium during goldfish reproduction

We recently demonstrated that prostaglandin E2 PG¿ increases osteoclastic activity and induces bone resorption in both in vitro and in vivo experiments using goldfish. In the fish reproductive period, the plasma calcium (Ca) level in female teleosts increases remarkably to make vitellogenin, which is a major component of egg protein and a Ca-binding protein. In this period, however, there is no reported relationship between PGE2 and Ca metabolism in fish. To clarify the Ca metabolism in fish reproduction, we examined plasma PGE2 and Ca levels and measured tartrate-resistant acid phosphatase (TRAP) activities as an indicator of osteoclastic activity in goldfish. Plasma PGE2 levels in the reproductive stage significantly increased as compared with those in non-reproductive stages. Also, both plasma Ca and TRAP increased in the reproductive stage. Significant positive correlations were recognized between plasma Ca and the gonad somatic index (r=0.81, p<0.001), plasma Ca and plasma PGE2 levels (r=0.635, p<0.05), and plasma Ca and plasma TRAP activities (r=0.584, p<0.05) from the analysis using samples of both reproductive and nonreproductive stages. Taking these data into consideration, we suggested that PGE, acts on osteoclasts and increases plasma Ca as a result of osteoclastic bone resorption, and we concluded that PGE, is an important hormone in Ca metabolism during fish reproduction

Monohydroxylated polycyclic aromatic hydrocarbons inhibit both osteoclastic and osteoblastic activities in teleost scales

金沢大学環日本海域環境研究センター生物多様性研究部門Aims: We previously demonstrated that monohydroxylated polycyclic aromatic hydrocarbons (OHPAHs) bound to a human estrogen receptor (ER) by a yeast two-hybrid assay, but polycyclic aromatic hydrocarbons did not have a binding activity. Therefore, the direct effect of 3-hydroxybenz[a]anthracene (3-OHBaA) and 4-hydroxybenz[a]anthracene (4-OHBaA) on osteoclasts and osteoblasts in teleosts was examined. As a negative control, 1-hydroxypyrene (1-OHPy), which has no binding activity to human ER, was used. Main methods: The effect of OHPAHs on osteoclasts and osteoblasts was examined by an assay system using teleost scale as each marker: tartrate-resistant acid phosphatase for osteoclasts and alkaline phosphatase for osteoblasts. Changes in cathepsin K (an osteoclastic marker) and insulin-like growth factor-I (IGF-I) (an osteoblastic marker) mRNA expressions in 4-OHBaA-treated goldfish scales were examined by using a reverse transcription-polymerase chain reaction. Key findings: In both goldfish (a freshwater teleost) and wrasse (a marine teleost), the osteoclastic activity in the scales was significantly suppressed by 3-OHBaA and 4-OHBaA, although 1-OHPy did not affect the osteoclastic activity. In reference to osteoblasts, the osteoblastic activity decreased with both 3-OHBaA and 4-OHBaA and did not change with the 1-OHPy treatment. However, 17β-estradiol (E2) significantly increased both the osteoclastic and osteoblastic activities in the scales of both goldfish and wrasse. The mRNA expressions of both cathepsin K and IGF-I decreased in the 4-OHBaA-treated scales but increased in the E2-treated scales. Significance: The current data are the first to demonstrate that 3-OHBaA and 4-OHBaA inhibited both osteoclasts and osteoblasts and disrupted the bone metabolism in teleosts. © 2009 Elsevier Inc. All rights reserved

Calcitonin-typical suppression of osteoclastic activity by amphioxus calcitonin superfamily peptides and insights into the evolutionary conservation and diversity of their structures

Calcitonin (CT) is a hormone that decreases serum calcium level by suppressing osteoclastic activity in the vertebrate bone. In vertebrates, the structure-function relationship of CTs has been studied extensively. We recently identified three CT superfamily peptides, Bf-CTFP1 to 3, and clarified the molecular and functional characteristics of their receptor and receptor activity-modifying protein in amphioxus, Branchiostoma floridae. However, the CT activity of Bf-CTFPs has yet to be investigated. In the present study, a functional analysis of Bf-CTFPs was performed using goldfish scales having both osteoclasts and osteoblasts. All Bf-CTFPs suppressed osteoclastic activity via a goldfish CT receptor. Although the primary amino acid sequences of the Bf-CTFPs showed low sequence similarity to vertebrate CTs, Bf-CTFP1 to 3 share three amino acids, Thr25, Thr27, and Pro32-NH2, that are required for receptor binding, with salmon CT. Moreover, homology model analysis revealed that the Bf-CTFPs form alpha-helical structures. The alpha-helical position and length of Bf-CTFP1 and 2 were conserved with those of a highly potent ligand, teleost CT. Interestingly, the composition of the alpha-helix of Bf-CTFP3 differed from those of teleost CT, despite that the action of Bf-CTFP3 on goldfish scales was the same as that of Bf-CTFP1 and 2. Collectively, the present study provides new insights into the structure-function relationship of CT and its functional evolution in chordates. © 2017 Elsevier Inc.Embargo Period 12 month

Effects of inorganic mercury and methylmercury on osteoclasts and osteoblasts in the scales of the marine teleost as a model system of bone

To evaluate the effects of inorganic mercury (InHg) and methylmercury (MeHg) on bone metabolism in a marine teleost, the activity of tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) as indicators of such activity in osteoclasts and osteoblasts, respectively, were examined in scales of nibbler fish (Girella punctata). We found several lines of scales with nearly the same TRAP and ALP activity levels. Using these scales, we evaluated the influence of InHg and MeHg. TRAP activity in the scales treated with InHg (10-5 and 10-4 M) and MeHg (10-6 to 10-4 M) during 6 hrs of incubation decreased significantly. In contrast, ALP activity decreased after exposure to InHg (10-5 and 10-4 M) and MeHg (10-6 to 10-4 M) for 18 and 36 hrs, although its activity did not change after 6 hrs of incubation. As in enzyme activity 6 hrs after incubation, mRNA expression of TRAP (osteoclastic marker) decreased significantly with InHg and MeHg treatment, while that of collagen (osteoblastic marker) did not change significantly. At 6 hrs after incubation, the mRNA expression of metallothionein, which is a metal-binding protein in osteoblasts, was significantly increased following treatment with InHg or MeHg, suggesting that it may be involved in the protection of osteoblasts against mercury exposure up to 6 hrs after incubation. To our knowledge, this is the first report of the effects of mercury on osteoclasts and osteoblasts using marine teleost scale as a model system of bone. © 2014 Zoological Society of Japan

Parathyroid hormone 1 (1-34) acts on the scales and involves calcium metabolism in goldfish

金沢大学環日本海域環境研究センターThe effect of fugu parathyroid hormone 1 (fugu PTH1) on osteoblasts and osteoclasts in teleosts was examined with an assay system using teleost scale and the following markers: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Synthetic fugu PTH1 (1-34) (100 pg/ml-10 ng/ml) significantly increased ALP activity at 6 h of incubation. High-dose (10 ng/ml) fugu PTH1 significantly increased ALP activity even after 18 h of incubation. In the case of TRAP activity, fugu PTH1 did not change at 6 h of incubation, but fugu PTH1 (100 pg/ml-10 ng/ml) significantly increased TRAP activity at 18 h. Similar results were obtained for human PTH (1-34), but there was an even greater response with fugu PTH1 than with human PTH. In vitro, we demonstrated that both the receptor activator of the NF-κB ligand in osteoblasts and the receptor activator NF-κB mRNA expression in osteoclasts increased significantly by fugu PTH1 treatment. In an in vivo experiment, fugu PTH1 induced hypercalcemia resulted from the increase of both osteoblastic and osteoclastic activities in the scale as well as the decrease of scale calcium contents after fugu PTH1 injection. In addition, an in vitro experiment with intramuscular autotransplanted scale indicated that the ratio of multinucleated osteoclasts/mononucleated osteoclasts in PTH-treated scales was significantly higher than that in the control scales. Thus, we concluded that PTH acts on osteoblasts and osteoclasts in the scales and regulates calcium metabolism in goldfish. © 2011 Elsevier Inc. All rights reserved