Cartilaginous fish comprise two subclasses, the Holocephali (chimaeras) and Elasmobranchii (sharks, skates and rays). Little is known about osmoregulatory mechanisms in holocephalan fishes except that they conduct urea-based osmoregulation, as in elasmobranchs. In the present study, we examined the ornithine urea cycle (OUC) enzymes that play a role in urea biosynthesis in the holocephalan elephant fish, Callorhinchus milii (cm). We obtained a single mRNA encoding carbamoyl phosphate synthetase III (cmCPSIII) and ornithine transcarbamylase (cmOTC), and two mRNAs encoding glutamine synthetases (cmGSs) and two arginases (cmARGs), respectively. The two cmGSs were structurally and functionally separated into two types: brain/liver/kidney-type cinGS1 and muscle-type cmGS2. Furthermore, two alternatively spliced transcripts with different sizes were found for cmgs1 gene. The longer transcript has a putative mitochondrial targeting signal (MTS) and was predominantly expressed in the liver and kidney. MTS was not found in the short form of cmGS1 and cmGS2. A high mRNA expression and enzyme activities were found in the liver and muscle. Furthermore, in various tissues examined, mRNA levels of all the enzymes except cmCPSIII were significantly increased after hatching. The data show that the liver is the important organ for urea biosynthesis in elephant fish, but, extrahepatic tissues such as the kidney and muscle may also contribute to the urea production. In addition to the role of the extrahepatic tissues and nitrogen metabolism, the molecular and functional characteristics of multiple isoforms of GSs and ARGs are discussed. (C) 2011 Elsevier Inc. All rights reserved.

Dogfish sharks are opportunistic predators, eating large meals at irregular intervals. Here we present a synthesis of data from several previous studies on responses in plasma metabolites after natural feeding and during prolonged fasting (up to 56 days), together with new data on changes in plasma concentrations of amino acids and non-esterified fatty acids. Post-prandial and long-term fasting responses were compared to control sharks fasted for 7 days, a typical inter-meal interval. A feeding frenzy was created in which dogfish were allowed to feed naturally on dead teleosts at two consumed ration levels, 2.6% and 5.5% of body weight. Most responses were more pronounced at the higher ration level. These included increases in urea and TMAO concentrations at 20 h, followed by stability through to 56 days of fasting. Ammonia levels were low and exhibited little short-term response to feeding, but declined to very low values during the extended fast. Glucose and beta-hydroxybutyrate both fell after feeding, the latter to a greater and more prolonged extent (up to 60 h), whereas acetoacetate did not change. During prolonged fasting, glucose concentrations were well regulated, but beta-hydroxybutyrate increased to 2-3-fold control levels. Total plasma amino acid concentrations increased in a biphasic fashion, with peaks at 6-20 h, and 48-60 h after the meal, followed by homeostasis during the extended fast. Essential and non-essential amino acids generally followed this same pattern, though some exhibited different trends after feeding: taurine, beta-alanine, and glycine (decreases or stability), alanine and glutamine (modest prolonged increases), and threonine, serine, asparagine, and valine (much larger short-term increases). Plasma non-esterified fatty acid concentrations declined markedly through 48 h after the 2.6% meal. These data are interpreted in light of companion studies showing elevations in aerobic metabolic rate, urea production, rectal gland function, metabolic base excretion, and activation of ornithine-urea cycle and aerobic enzymes after the meal, and muscle N-depletion but maintenance of osmolality and urea production during long-term fasting. (c) 2009 Elsevier Inc. All rights reserved.

Mitochondrial respiration and activities of key metabolic enzymes from liver and white skeletal muscle were compared between control aquatic slender lungfish Protopterus dolloi, and those exposed to air for 5 months. Activities of citrate synthase, glycogen phosphorylase, phosphofructokinase and pyruvate kinase in liver were not affected by air-exposure. In muscle, air-exposure reduced citrate synthase and pyruvate kinase activities (relative to tissue wet mass) by 63 and 50%, respectively. Liver carnitine palmitoyl transferase activity (relative to mitochondrial protein) decreased by half following air-exposure, but there was no change in muscle. In mitochondria isolated from muscle, state 3 and state 4 respiration were reduced by 74 and 89%, respectively following air-exposure, but liver mitochondria were not affected. In liver, air-exposure increased activities of ornithine-urea cycle enzymes including glutamine synthase, carbamoyl-phosphate synthase III and arginase, by 1.9- to 4.2-fold. Carbamoyl-phosphate synthase III activity could not be detected in muscle, indicating that urea is not synthesized in this tissue. These data suggest that skeletal muscle metabolism is downregulated in air-exposure, conserving energy and protein during a period when the animals cannot forage. In contrast, ATP production capacities in the liver are maintained, and this may permit expensive urea biosynthesis to continue during aerial exposure. (C) 2008 The Authors Journal compilation (C) 2008 The Fisheries Society of the British Isles.

Carnitine palmitoyltransferase (CPT) I is regulated by several genetic and non-genetic factors including allosteric inhibition, mitochondrial membrane composition and/or fluidity and transcriptional regulation of enzyme content. To determine the intrinsic differences in these regulating factors that may result in differences between tissues in fatty acid oxidation ability, mitochondria were isolated from red, white and heart muscles and liver tissue from rainbow trout. Maximal activity (V-max) for beta-oxidation enzymes and citrate synthase per mg tissue protein as well as CPT I in isolated mitochondria followed a pattern across tissues of red muscle> heart> white muscle liver suggesting both quantitative and qualitative differences in mitochondria. CPT I inhibition showed a similar pattern with the highest malonyl-CoA concentration to inhibit activity by 50% (IC50) found in red muscle while liver had the lowest. Tissue malonyl-CoA content was highest in white muscle with no differences between the other tissues. Interestingly, the gene expression profiles did not follow the same pattern as the tissue enzyme activity. CPT I mRNA expression was greatest in heart> red muscle>white muscle>liver. In contrast, PPAR alpha mRNA was greatest in the liver>red muscle> heart> white muscle. There were no significant differences in the mRNA expression of PPAR between tissues. As well, no significant differences were found in the mitochondrial membrane composition between tissues, however, there was a tendency for red muscle to exhibit higher proportions of PUFAs as well as a decreased PC:PE ratio, both of which would indicate increased membrane fluidity. In fact, there were significant correlations between IC50 of CPT I for malonyl-CoA and indicators of membrane fluidity across tissues. This supports the notion that sensitivity of CPT I to its allosteric regulator could be modulated by changes in mitochondrial membrane composition and/or fluidity. (C) 2008 Elsevier B.V. All rights reserved.

Experimental metabolic alkalosis is known to stimulate whole-animal urea production and active ion secretion by the rectal gland in the dogfish shark. Furthermore, recent evidence indicates that a marked alkaline tide (systemic metabolic alkalosis) follows feeding in this species and that the activities of the enzymes of the ornithine-urea cycle (OUC) for urea synthesis in skeletal muscle and liver and of energy metabolism and ion transport in the rectal gland are increased at this time. We therefore evaluated whether alkalosis and/or NaCl/volume loading (which also occurs with feeding) could serve as a signal for activation of these enzymes independent of nutrient loading. Fasted dogfish were infused for 20 h with either 500 mmol L(-1) NaHCO(3) (alkalosis + volume expansion) or 500 mmol L(-1) NaCl (volume expansion alone), both isosmotic to dogfish plasma, at a rate of 3 mL kg(-1) h(-1). NaHCO3 infusion progressively raised arterial pH to 8.28 (control = 7.85) and plasma [HCO(3)(-)] to 20.8 mmol L(-1) (control = 4.5 mmol L(-1)) at 20 h, with unchanged arterial Pco(2), whereas NaCl/volume loading had no effect on blood acid-base status. Rectal gland Na(+),K(+)-ATPase activity was increased 50% by NaCl loading and more than 100% by NaHCO(3) loading, indicating stimulatory effects of both volume expansion and alkalosis. Rectal gland lactate dehydrogenase activity was elevated 25% by both treatments, indicating volume expansion effects only, whereas neither treatment increased the activities of the aerobic enzymes citrate synthase, NADP-isocitrate dehydrogenase, or the ketone body-utilizing enzyme beta-hydroxybutyrate dehydrogenase in the rectal gland or liver. The activity of ornithine-citrulline transcarbamoylase in skeletal muscle was doubled by NaHCO(3) infusion, but neither treatment altered the activities of other OUC-related enzymes (glutamine synthetase, carbamoylphosphate synthetase III). We conclude that both the alkaline tide and salt loading/volume expansion act as signals to activate some but not all of the elevated metabolic pathways and iono-regulatory mechanisms needed during processing of a meal.

The rectal gland is the principal salt-secreting organ in elasmobranchs, yet its functional response to normal physiological variation (e.g., due to feeding, stress) has only recently been examined. To complement studies on acid-base, digestive, and osmoregulatory physiology in response to natural feeding, we investigated protein-level responses in the rectal gland of spiny dogfish (Squalus acanthias) 6 h, 20 h, and 5 days (reference control) after a meal. Our objective was to identify proteins involved in regulation of osmoregulatory and metabolic processes in response to feeding. Proteins were separated by two-dimensional gel electrophoresis, and protein spots that were significantly up- or down-regulated >2 fold (i.e., abundance increased more than 100% or decreased more than 50%) were detected using gel image analysis software. Of 684 proteins analyzed on 2D gels, 16 proteins changed significantly 6 h after feeding vs. 5 day controls (5 decreased; 11 increased), and 12 proteins changed > 2 fold 20 h after feeding vs. 5 day controls (2 decreased; 10 increased). Thirteen of these proteins were identified using mass spectrometry and classified into functional pathways using the PANTHER bioinformatics database. Rectal gland proteins that were regulated following feeding fell into three main categories: cytoskeletal/muscular (e.g., tropomyosin alpha chain, transgelin), energy metabolism (e.g., malate dehydrogenase, ATP synthase), and nucleotide metabolism (nucleoside diphosphate kinase). The data also revealed that previously documented increases in the activity of isocitrate dehydrogenase after feeding are at least partially due to increased abundance of a cytosolic, NADP-dependent isoform of this enzyme. One of the primary components of the rectal gland's response to feeding appears to be maintenance of the cellular supply of energy, which would be necessary to fuel increased activities of enzymes involved in salt secretion and oxidative metabolism in the rectal gland following a meal. (C) 2007 Elsevier Inc. All rights reserved.

Over 56 days of starvation, spiny dogfish Squalus acanthias lost c. 0.3% body mass per day and condition factor and hepato-somatic index declined, but plasma osmolality levels remained higher than seawater levels for the entire period; major osmolytes in the plasma, such as urea, trimethylamine oxide and inorganic ions did not change appreciably. Urea was always the dominant nitrogen waste and was excreted at a constant rate over the 56 day starvation period, suggesting that a minimum rate of urea loss to the environment is unavoidable. Significant amounts of unknown-nitrogen compounds were also excreted at rates higher than that of ammonia. The dogfish can maintain its osmolytes constant despite losing large amounts of nitrogen-rich urea, and therefore maintains plasma hyperosmotic regulation over long-term starvation. (c) 2008 The Authors Journal compilation (c) 2008 The Fisheries Society of the British Isles.

Interspecific differences in the ability to excrete urea in four gobiid fishes, Mugilogobius abei, M. chulae, M. sp. 1 and M. sp. 2, in response to elevated external ammonia, were compared and set against the phylogenetic relationships of species, following molecular phylogenetic analyses using a portion of mitochondrially-encoded 12S ribosomal RNA and tRNA-Val genes, which were sequenced from five species of Mugilogobius. The resulting tree, based on 710 base pairs of aligned sequences, was statistically robust and indicated two major clades, (M. abei, M. sp. 1 and M. chulae) and (M. parvus and M. sp. 2), respectively. High ureagenic ability was demonstrated in M. abei and M. sp. 1, being sister species according to the phylogenetic analysis, while the remaining species having a low level of ability. The two former species are restricted to temperate and subtropical Japan, whereas the others are widely distributed throughout tropical Asia. The most parsimonious reconstruction of these features suggested that ancestral Mugilogobius, probably widely distributed in tropical Asia, may had low ureagenic ability. The high ureagenic ability of the temperate species may have evolved concurrently with the northward spread of Mugilogobius from the tropical zone.

To examine the transition to ureogenesis, the gobiid fish Mugilogobius abei was immersed in 2 mmoll-1 NH4HCO3 or a 15N-labelled ammonia solution [1 mmoll-1 (15NH4)2SO4, pH 8.0] for 4-8 days. When exposed to 2 mmoll-1 NH4HCO3 or 15N-labelled ammonia solution for 4 days, the rate of urea excretion increased to seven times that of the control (in 20 % synthetic sea water) and remained at this level for 4 days. The proportion of nitrogen excreted as urea reached 62 % of total nitrogen excretion (ammonia-N + urea-N). 15N-enrichment of the amide-N in glutamine in the tissues of fish exposed to 15N-labelled ammonia was virtually the same as that of ammonia-N: i.e. approximately twice that of urea-N in the excreta and the tissues. Glutamine contents and glutamine synthetase activities in the liver and muscle increased greatly following exposure to ammonia. Urea and citrulline contents in the muscle and whole body of the exposed fish increased significantly, whereas uric acid contents remained unchanged. Carbamoyl phosphate synthetase III (CPSase III) mRNA expression and CPSase III activity were detected in the muscle, skin and gill, but levels were negligible in the liver. Furthermore, all other ornithine-urea cycle (O-UC) enzymes were also detected in muscle, skin and gill. Thus, M. abei clearly shows the transition from ammoniotely to ureotely under ammonia-loading condition and is able to produce urea mainly via the O-UC operating in multiple non-hepatic tissues as a means for ammonia detoxification.

出張講座

プログラミング教育、海南市立五月山保育園,日付:26日

出張講座

ボトルアクアリウムで生き物観察、海南市立五月山保育園,日付:17日

プログラミング、理科

プログラミングアプリの一つであるプログラミングゼミを使って、児童が描いた海の生き物を画面上で動かすプログラミング指導を行った。

出張講座

セミの抜け殻観察、海南市立五月山保育園,日付:22日

講演講師

和歌山県教育委員会教育職員免許法認定講習（理科）に係る講義

出張講座

種と実の観察、海南市立五月山保育園,日付:30日

プログラミング、理科

プログラミングアプリの一つであるscratchを使って、児童が描いた海の生き物を画面上で動かすプログラミング指導を行った。

出張講座

プログラミング、海南市立五月山保育園,日付:4日

講演講師等

講師

出張講座

昆虫の観察、海南市立五月山保育園,日付:4日

出張講座

種と実の観察、海南市立五月山保育園,日付:26日

講演講師等

講師,任期:2019年12月～

小・中・高校生を対象とした学部体験入学・出張講座等

まちかど土曜楽交

小・中・高校生を対象とした学部体験入学・出張講座等

和歌山大学附属中学校

公開講座・講演会の企画・講師等

小学生がサポートの大学生と一緒に，半年かけて一つのサイエンスプロジェクトを行い，おもしろ科学まつりで発表する

小・中・高校生を対象とした学部体験入学・出張講座等

海南高校

小・中・高校生を対象とした学部体験入学・出張講座等

和歌山大学附属中学校

公開講座・講演会の企画・講師等

県内のこどもたちに科学を体験させる

小・中・高校生を対象とした学部体験入学・出張講座等

向陽高校，Dartford Grammar School ,日付:29 10 2012

小・中・高校生を対象とした学部体験入学・出張講座等

海南高校,日付:11 12 2012

小・中・高校生を対象とした学部体験入学・出張講座等

和歌山大学附属中学校,日付:9 21 2012

公開講座・講演会の企画・講師等

県内のこどもたちに科学を体験させる

小・中・高校生を対象とした学部体験入学・出張講座等

海南高校,日付:6 12 2011

小・中・高校生を対象とした学部体験入学・出張講座等

向陽高校，Dartford Grammar School ,日付:18 10 2011

小・中・高校生を対象とした学部体験入学・出張講座等

和歌山大学附属中学校,日付:6 17 2010

小・中・高校生を対象とした学部体験入学・出張講座等

海南高校,日付:9 12 2010

公開講座・講演会の企画・講師等

県内のこどもたちに科学を体験させる

公開講座・講演会の企画・講師等

観察・実験による苦手科目の力量向上

公開講座・講演会の企画・講師等

県内のこどもたちに科学を体験させる