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Vance L Trudeau
Genetic manipulation of teleost endocrine systems started with transgenic overexpression of pituitary growth hormone. Such strategies enhance growth and reduce fertility, but the fish still breed. Genome editing using transcription activator-like effector nuclease in zebrafish and medaka has established the role of follicle stimulating hormone for gonadal development and luteinizing hormone for ovulation. Attempts to genetically manipulate the hypophysiotropic neuropeptidergic systems have been less successful...
2018: Frontiers in Neuroscience
Hiromi Sakata-Haga, Maimi Uchishiba, Hiroki Shimada, Tsuyoshi Tsukada, Mayumi Mitani, Tomohiro Arikawa, Hiroki Shoji, Toshihisa Hatta
Here we propose a new protocol for whole-mount bone staining, which allows the rapid preparation of highly cleared and nondestructive specimens. It only takes 3 days to complete whole procedure for small vertebrates, such as medaka, zebrafish, and Xenopus frogs. In this procedure, we used a newly developed fixative containing formalin, Triton X-100, and potassium hydroxide, which allows the fixation, decolorization, and transparentization of specimens at the same time. A bone staining solution containing alizarin red S with ethylene glycol and a clearing solution containing Tween 20 and potassium hydroxide also contributed the specificity and swiftness of this new system...
May 10, 2018: Scientific Reports
Salvador Sastre, Carlos Fernández Torija, Irene Atiénzar Pertusa, Eulalia María Beltrán, María Victoria Pablos, Miguel González-Doncel
By considering chlorpyrifos (CPF), an organophosphorus pesticide with known mechanisms of action that affect neurobehavioral development, we assessed the validity and sensitivity of a miniaturized swim flume by investigating the effects of the insecticide on swimming behavior in medaka (Oryzias latipes) fish growing stages. Medaka in three developmental periods, namely 0, 20 and 40 day-old post-hatch (i.e. time points 0, 20 and 40, respectively), were exposed to CPF (12.5, 25, 50 and 100 μg/L) for 48 h under semi-static conditions...
April 21, 2018: Aquatic Toxicology
Wenjing Cai, Shan He, Xu-Fang Liang, Xiaochen Yuan
Although previous studies have indicated importance of taste receptors in food habits formation in mammals, little is known about those in fish. Grass carp is an excellent model for studying vegetarian adaptation, as it shows food habit transition from carnivore to herbivore. In the present study, pseudogenization or frameshift mutations of the umami receptors that hypothesized related to dietary switch in vertebrates, were not found in grass carp, suggesting other mechanisms for vegetarian adaptation in grass carp...
May 2, 2018: Scientific Reports
Joanna Dodzian, Sam Kean, Jens Seidel, Dario Riccardo Valenzano
The development of husbandry practices in non-model laboratory fish used for experimental purposes has greatly benefited from the establishment of reference fish model systems, such as zebrafish and medaka. In recent years, an emerging fish - the turquoise killifish (Nothobranchius furzeri) - has been adopted by a growing number of research groups in the fields of biology of aging and ecology. With a captive life span of 4 - 8 months, this species is the shortest-lived vertebrate raised in captivity and allows the scientific community to test - in a short time - experimental interventions that can lead to alterations of the aging rate and life expectancy...
April 11, 2018: Journal of Visualized Experiments: JoVE
Manabu Yonekura, Nami Kondoh, Chong Han, Yuichi Toyama, Takayoshi Ohba, Kyoichi Ono, Shirou Itagaki, Hirofumi Tomita, Manabu Murakami
The heart of the medaka, a small fish native to East Asia, has electrophysiological aspects similar to mammalian hearts. We found that the heart rates of medaka were more similar to humans than mice or rats. Medaka exhibited similar electrocardiogram patterns to those of humans, suggesting a similarity in cardiac impulse formation and propagation. Their hearts also exhibited similar responsiveness to verapamil, a calcium channel antagonist; atropine, a parasympathetic nerve blocker; propranolol, a sympathetic β-adrenergic blocker; and isoproterenol, a sympathetic β-adrenergic agonist...
April 12, 2018: Journal of Pharmacological Sciences
Richard A Brain, Suzanne Z Schneider, Julie C Anderson, Loren D Knopper, Jeffrey C Wolf, Mark L Hanson
Short-term reproduction assays were conducted with fathead minnow (Pimephales promelas) and Japanese medaka (Oryzias latipes) to evaluate responses from atrazine exposure at environmentally relevant concentrations and above. Breeding groups of fish with multiple males and females were exposed to atrazine under flow-through conditions. Fathead minnows were exposed to mean measured concentrations of 1.0, 10, 26, 52, and 105 μg atrazine/L for 28 days. Medaka were exposed to mean measured concentrations of 9...
April 16, 2018: Chemosphere
A H Sayed, Rania F Ismail, Hiroshi Mitani
The negative effects of ambient ultraviolet (UVA) on the water environment have been recently highlighted; UVA can create deleterious effects by stimulating stress on pelagic organisms. Little is known about UVA effects on oocyte characteristics of female fish. In the present study we explored the effects of exposure to ecologically relevant levels of simulated UVA radiation on ovaries of two major strains WT (HdrR) and P53 (-/-) of medaka (Oryzias latipes) mature female. Fish were assigned to control and three UVA-exposed groups as (15 min, 30 min, and 60 min/day) for three days and sample selection was 24 h and 14 days after exposure...
April 12, 2018: Journal of Photochemistry and Photobiology. B, Biology
Erika Ishihara, Hiroshi Nishina
The vertebrate body shape is formed by the specific sizes and shapes of its resident tissues and organs, whose alignments are essential for proper functioning. To maintain tissue and organ shape, and thereby function, it is necessary to remove senescent, transformed, and/or damaged cells, which impair function and can lead to tumorigenesis. However, the molecular mechanisms underlying three-dimensional (3D) organ formation and homeostasis are not fully clear. Yes-associated protein (YAP) is a transcriptional co-activator that is involved in organ size control and tumorigenesis...
April 17, 2018: Cancers
Vladimir Soukup, Simona Mrstakova, Zbynek Kozmik
The epithalamic region of fishes shows prominent left-right asymmetries that are executed by nodal signaling upstream of the asymmetry-determining transcription factor pitx2. Previous reports have identified that nodal controls the left-sided pitx2 expression in the lateral plate mesoderm through an enhancer present in the last intron of this gene. However, whether similar regulation occurs also in the case of epithalamic asymmetry is currently unresolved. Here, we address some of the cis-regulatory information that control asymmetric pitx2 expression in epithalamus by presenting a Tg(pitx2:EGFP) 116-17 transgenic medaka model, which expresses enhanced green fluorescent protein (EGFP) under control of an intronic enhancer...
April 16, 2018: Development Genes and Evolution
Hiroshi Ishibashi, Masaya Uchida, Keisuke Yoshimoto, Yuta Imamura, Ryoko Yamamoto, Yoshinori Ikenaka, Masahito Kawai, Nobuhiro Ichikawa, Yuji Takao, Nobuaki Tominaga, Yasuhiro Ishibashi, Koji Arizono
In this study, we determined the concentration of equine estrogens, such as equilin (Eq) and equilenin (Eqn), in the river water collected from nine research stations in Hokkaido, Japan. The LC-MS/MS analysis revealed that Eq concentrations were 2.7 ± 6.7, 0.22 ± 0.12, and 1.2 ± 0.64 ng/L in Sep 2015, Feb 2016, and Jul 2016, respectively. Eqn had concentration levels similar to those of Eq. Comparison of the concentrations at nine research stations showed that seasonal variation was observed in the detected Eq and Eqn concentration levels...
April 13, 2018: Environmental Pollution
Yusuke Nagao, Hiroyuki Takada, Motohiro Miyadai, Tomoko Adachi, Ryoko Seki, Yasuhiro Kamei, Ikuyo Hara, Yoshihito Taniguchi, Kiyoshi Naruse, Masahiko Hibi, Robert N Kelsh, Hisashi Hashimoto
Mechanisms generating diverse cell types from multipotent progenitors are fundamental for normal development. Pigment cells are derived from multipotent neural crest cells and their diversity in teleosts provides an excellent model for studying mechanisms controlling fate specification of distinct cell types. Zebrafish have three types of pigment cells (melanocytes, iridophores and xanthophores) while medaka have four (three shared with zebrafish, plus leucophores), raising questions about how conserved mechanisms of fate specification of each pigment cell type are in these fish...
April 2018: PLoS Genetics
Florencia Cavodeassi
Over the last thirty years, fish models, such as the zebrafish and medaka, have become essential to pursue developmental studies and model human disease. Community efforts have led to the generation of wide collections of mutants, a complete sequence of their genomes, and the development of sophisticated genetic tools, enabling the manipulation of gene activity and labelling and tracking of specific groups of cells during embryonic development. When combined with the accessibility and optical clarity of fish embryos, these approaches have made of them an unbeatable model to monitor developmental processes in vivo and in real time...
February 28, 2018: Journal of Developmental Biology
Euiyeon Lee, Hyunjin Jeon, Chungwon Kang, Seonock Woo, Seungshic Yum, Youngeun Kwon
Environmental pollution by various industrial chemicals and biological agents poses serious risks to human health. Especially, marine contamination by potentially toxic elements (PTEs) has become a global concern in recent years. Many efforts have been undertaken to monitor the PTE contamination of the aquatic environment. However, there are few approaches available to assess the PTE exposure of aquatic organisms. In this research, we developed a strategy to evaluate the heavy metal exposure of marine organisms, by measuring the expression levels of metallothionein protein derived from Oryzias javanicus (OjaMT)...
April 2, 2018: Sensors
Toshiya Nishimura, Kazuki Yamada, Chika Fujimori, Mariko Kikuchi, Toshihiro Kawasaki, Kellee R Siegfried, Noriyoshi Sakai, Minoru Tanaka
Germ cells are the only cells that can transfer genetic materials to the next generation via the sperm or egg. However, recent analyses in teleosts revealed another essential role of germ cells: feminizing the gonads. In our study, medaka mutants in which gametogenesis was blocked at specific stages provides the novel view that the feminizing effect of germ cells occurs in parallel with other reproductive elements, such as meiosis, the sexual fate decision of germ cells, and gametogenesis. Germ cells in medaka may have a potential to feminize gonads at the moment they have developed...
March 2018: PLoS Genetics
Monia Porpora, Simona Sauchella, Laura Rinaldi, Rossella Delle Donne, Maria Sepe, Omar Torres-Quesada, Daniela Intartaglia, Corrado Garbi, Luigi Insabato, Margherita Santoriello, Verena A Bachmann, Matthis Synofzik, Herbert H Lindner, Ivan Conte, Eduard Stefan, Antonio Feliciello
The primary cilium emanates from the cell surface of growth-arrested cells and plays a central role in vertebrate development and tissue homeostasis. The mechanisms that control ciliogenesis have been extensively explored. However, the intersection between GPCR signaling and the ubiquitin pathway in the control of cilium stability are unknown. Here we observe that cAMP elevation promotes cilia resorption. At centriolar satellites, we identify a multimeric complex nucleated by PCM1 that includes two kinases, NEK10 and PKA, and the E3 ubiquitin ligase CHIP...
March 26, 2018: Nature Communications
Yawen Liu, Xinhong Wang, Yongyu Li, Xixi Chen
Toxicological effects of sulfamethazine (SM2 ) have garnered increasing concern due to its wide applications in aquaculture and persistence in the aquatic environment. Most studies have main focused on freshwater fish (i.e. zebrafish), while information regarding effects of SM2 on marine species is still scarce. Here, the hepatotoxicities in marine medaka (Oryzias melastigma) with an increasing SM2 concentration exposures (0.01 mg/L, 0.1 mg/L and 1 mg/L) were assessed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF/MS) based metabolomics...
March 8, 2018: Aquatic Toxicology
Eitaro Sawayama, Daiki Noguchi, Kei Nakayama, Motohiro Takagi
We previously reported a body color deformity in juvenile red sea bream, which shows transparency in the juvenile stage because of delayed chromatophore development compared with normal individuals, and this finding suggested a genetic cause based on parentage assessments. To conduct marker-assisted selection to eliminate broodstock inheriting the causative gene, developing DNA markers associated with the phenotype was needed. We first conducted SNP mining based on AFLP analysis using bulked-DNA from normal and transparent individuals...
March 23, 2018: Marine Biotechnology
Yuko Watanabe, Eri Furukawa, Hideki Tatsukawa, Hisashi Hashimoto, Yasuhiro Kamei, Yoshihito Taniguchi, Kiyotaka Hitomi
Transglutaminase (TG) is an essential enzyme to catalyze cross-linking reactions of epidermal proteins. Recently, we biochemically characterized human skin TG orthologues for medaka (Oryzias latipes), a model fish. By genome editing, gene-modified fishes for the two orthologues were obtained, both of which lack the ordinal enzymes. These fish appeared to exhibit higher susceptibility to osmolality at the period of larvae.
March 23, 2018: Bioscience, Biotechnology, and Biochemistry
Yasuhiro Tonoyama, Minori Shinya, Atsushi Toyoda, Takeshi Kitano, Atsunori Oga, Toshiyuki Nishimaki, Takafumi Katsumura, Hiroki Oota, Miles T Wan, Bill W P Yip, Mok O L Helen, Shinichi Chisada, Tomonori Deguchi, Doris W T Au, Kiyoshi Naruse, Yasuhiro Kamei, Yoshihito Taniguchi
Lamin is an intermediate protein underlying the nuclear envelope and it plays a key role in maintaining the integrity of the nucleus. A defect in the processing of its precursor by a metalloprotease, ZMPSTE24, results in the accumulation of farnesylated prelamin in the nucleus and causes various diseases, including Hutchinson-Gilford progeria syndrome (HGPS). However, the role of lamin processing is unclear in fish species. Here, we generated zmpste24-deficient medaka and evaluated their phenotype. Unlike humans and mice, homozygous mutants did not show growth defects or lifespan shortening, despite lamin precursor accumulation...
March 19, 2018: Comparative Biochemistry and Physiology. Toxicology & Pharmacology: CBP
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