Glycoprotein hormone in the pituitary of hagfish and its evolutionary implications     

Katsuhisa Uchida  Shunsuke Moriyama  Stacia A. Sower  Masumi Nozaki 《Fish physiology and biochemistry》2013,39(1):75-83

The pituitary gland is present in all vertebrates, from agnathans (jawless vertebrates) to mammals, but not in invertebrates. Reproduction in gnathostomes (jawed vertebrates) is controlled by two pituitary gonadotropins (GTHs), luteinizing hormone and follicle-stimulating hormone, which are part of the pituitary glycoprotein hormone (GPH) family. Hagfishes, which lack both jaws and vertebrae, are considered the most primitive vertebrate known, living or extinct. Accordingly, they are of particular importance in understanding the evolution of the pituitary GPHs and their functions related to vertebrate reproduction. Nevertheless, key elements of the reproductive endocrine system in hagfish have yet to be elucidated. Our current report has revealed the first identification of a functional GPH composed of two subunits that possess gonadotropic action at the pituitary of brown hagfish. It seems most likely that an ancestral GPH gave rise to only one GTH in hagfish pituitary and that multiplicity of GPHs arose later during the early evolution of gnathostomes. This paper briefly summarizes the latest findings on the hagfish GPH from an evolutionary point of view.  相似文献   

Control of Colletotrichum fructicola on strawberry with a foliar spray of neutral electrolyzed water through an overhead irrigation system     

Yoshihiko Hirayama  Shunsuke Asano  Keiichiroh Watanabe  Yasuhiro Sakamoto  Masaaki Ozaki  Ken’o Okayama  Satoshi T. Ohki  Motoaki Tojo 《Journal of General Plant Pathology》2016,82(4):186-189

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Biomass allocation and nitrogen limitation in a Cryptomeria japonica plantation chronosequence     

Ryunosuke Tateno  Keitaro Fukushima  Reiji Fujimaki  Tetsuya Shimamura  Masami Ohgi  Hirotsugu Arai  Nobuhito Ohte  Naoko Tokuchi  Takahito Yoshioka 《Journal of Forest Research》2009,14(5):276-285

We investigated soil net nitrogen mineralization rate, above- and belowground biomass allocation, and nitrogen use in a Cryptomeria japonica plantation chronosequence. Total biomass accumulation showed an asymptotic accretion pattern, and the peak total biomass accumulation rate occurred approximately 30 years after afforestation. Soil net nitrogen mineralization rate was lowest 30 years after afforestation. Between years 30 and 88, net nitrogen mineralization increased again. These results indicate that an imbalance in soil nitrogen supply and plant nitrogen demand occurred approximately 30 years after afforestation. Furthermore, leaf nitrogen concentration, which was used as an index of plant nitrogen status, was lower in mature forest than in young forest, suggesting that mature stands did not take up nitrogen as successfully. If soil resources such as nitrogen limit plant growth, plants may increase biomass allocation to fine root structure; however, fine root biomass was not higher in 30- and 88-year-old stands than in younger stands, suggesting that changes in biomass allocation may not be effective against nitrogen deficiency in a C. japonica plantation chronosequence.  相似文献   

Oocyte maturation and active motility of spermatozoa are triggered by retinoic acid in pen shell <Emphasis Type="Italic">Atrina pectinata</Emphasis>     

Masahiko Awaji  Toshie Matsumoto  Daisuke Ojima  Shunsuke Inoue  Michio Suzuki  Masaei Kanematsu 《Fisheries Science》2018,84(3):535-551

For recovery of the declining population of pen shells in the wild, the production of pen shell juveniles for transplantation or aquaculture is underway in Japan. For more stable juvenile production, artificial fertilization methods for pen shells are needed, but methods to induce oocyte maturation (meiosis resumption) used in other bivalves, which make oocytes fertilizable, were ineffective for pen shells. Here, we report evidence showing that retinoic acid (RA) has strong activity in inducing oocyte maturation and activating sperm motility in pen shells. Treatment of fully developed oocytes with 1.0 μM all-trans-RA (at-RA) induced germinal vesicle breakdown, a typical morphological sign of oocyte maturation, but 1.0 μM at-retinol and at-retinal, 2 mM ammonia, and 1.0 μM serotonin were ineffective. Treatment with at-RA for 30 min was sufficient for oocyte maturation and was more potent than its isomers, 9-cis- and 13-cis-RA. Parallel results were obtained for sperm motility activation. Oocyte responsiveness to at-RA increased during the final stage of ovary development. Artificial fertilization was successful only with the oocytes treated with at-RA, and fertilized eggs developed to D-shaped (veliger) larvae without apparent morphological abnormalities. These results indicate the possible application of RA for the artificial fertilization of pen shells.  相似文献   

A hydro-environmental watershed model improved in canal-aquifer water exchange process     

Chie Imagawa  Junichiro Takeuchi  Toshihiko Kawachi  Kei Ishida  Shunsuke Chono  Natsuki Buma 《Paddy and Water Environment》2011,9(4):425-439

Long-term simulation using the distributed hydro-environmental watershed model is efficacious for assessing irrigation impacts on hydrological cycle in detail and for implementing watershed management successfully. In this article, the previously developed hydro-environmental watershed model (HEWM-1) is improved in the water exchange process caused by surface water-groundwater interaction via drainage canals and/or underdrains. The time-varying stream flow in canals is described by the complete one-dimensional shallow water equations in a newly introduced submodel, the open channel flow submodel. This submodel coordinates with the other submodels: the tank, soil moisture and groundwater flow submodels which are interlinked in a cascade manner. The improved model (HEWM-2) is applied to an agricultural watershed covering an area from an alluvial fan onto a nearly level alluvial plain, to be validated. The simulation by HEWM-2 is informative for identifying whether any drainage canal is gaining or losing water in relation to groundwater level. It could thus provide useful information for conserving a complex network of drainage canals which also functions as a passage for aquatic animals like fishes.  相似文献   

Growth performance of juvenile kuruma shrimp,Marsupenaeus japonicus (Bate) fed diets replacing fishmeal with soybean meal          下载免费PDF全文

Mahbuba Bulbul  Shunsuke Koshio  Manabu Ishikawa  Saichiro Yokoyama  Md. Abdul Kader 《Aquaculture Research》2015,46(3):572-580

A feeding trail was conducted to evaluate the effect of lowering dietary fishmeal (FM) levels while increasing levels of dehulled soybean meal (SBM) on growth, nutrient utilization and body composition of juvenile kuruma shrimp, Marsupenaeus japonicas. Five experimental diets were formulated to be isoenergetic, isolipidic and isonitrogenous with decreasing FM levels from 40 to 16% while increasing SBM from 0 to 33% respectively. Quadruplicate groups of shrimp (initial wt = 1.5 g) were fed the test diets for 56 days under the flow‐through system. There were no significant differences in final weight (g) and specific growth rate (SGR, % day) among shrimp fed FM40, FM34, FM28 and FM22 diets respectively. Growth parameters significantly decreased in shrimp when fed FM16 diet, which was the lowest level of FM. Feed intake was positively correlated with the SGR of shrimp, and the lowest one was found in shrimp fed FM16 diet. Protein gain and retention, whole body lipid, arginine and methionine significantly decreased in FM16 fed group. Thus, it is concluded that dietary FM could be reduced down to 22% with SBM without compromising growth, nutrient utilization and retention, and whole body composition of kuruma shrimp.  相似文献   

Assessment of species specificity of moulting accelerating compounds in Lepidoptera: comparison of activity between Bombyx mori and Spodoptera littoralis by in vitro reporter and in vivo toxicity assays     

Thomas Soin  Ellen De Geyter  Hadi Mosallanejad  Masatoshi Iga  David Martín  Shunsuke Ozaki  Shigeki Kitsuda  Toshiyuki Harada  Hisashi Miyagawa  Dimitra Stefanou  Georgia Kotzia  Rodica Efrose  Vassiliki Labropoulou  Danny Geelen  Kostas Iatrou  Yoshiaki Nakagawa  Colin R Janssen  Guy Smagghe  Luc Swevers 《Pest management science》2010,66(5):526-535

BACKGROUND: Dibenzoylhydrazine analogues have been developed successfully as a new group of insect growth regulators, called ecdysone agonists or moulting accelerating compounds. A notable feature is their high activity against lepidopteran insects, raising the question as to whether species‐specific analogues can be isolated. In this study, the specificity of ecdysone agonists was addressed through a comparative analysis in two important lepidopterans, the silkworm Bombyx mori L. and the cotton leafworm Spodoptera littoralis (Boisd.). RESULTS: When collections of non‐steroidal ecdysone agonists containing different mother structures (dibenzoylhydrazine, acylaminoketone, tetrahydroquinoline) were tested, in vitro reporter assays showed minor differences using cell lines derived from both species. However, when compounds with high ecdysone agonist activity were examined in toxicity assays, larvicidal activity differed considerably. Of note was the identification of three dibenzoylhydrazine analogues with > 100‐fold higher activity against Bombyx than against Spodoptera larvae. CONCLUSION: The present study demonstrated that species‐specific ecdysone‐agonist‐based insecticides can be developed, but their species specificity is not based on differences in the activation of the ecdysone receptor but rather on unidentified in vivo parameters such as permeability of the cuticle, uptake/excretion by the gut or metabolic detoxification. Copyright © 2010 Society of Chemical Industry  相似文献   

Moscatilin from Dendrobium nobile, a naturally occurring bibenzyl compound with potential antimutagenic activity.   总被引：4，自引：0，他引：4  

M Miyazawa  H Shimamura  S Nakamura  W Sugiura  H Kosaka  H Kameoka 《Journal of agricultural and food chemistry》1999,47(5):2163-2167

A bibenzyl compound that possesses antimutagenic activity was isolated from the storage stem of Dendrobium nobile. The isolated compound suppressed the expression of the umu gene following the induction of SOS response in Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compound was mainly localized in the n-hexane extract fraction of the processed D. nobile. This n-hexane fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compound. EI-MS and (1)H and (13)C NMR spectroscopy were then used to delineate the structure of the compound that confers the observed antimutagenic activity. Comparison of the obtained spectrum with that found in the literature indicated that moscatilin is the secondary suppressive compound. When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, moscatilin suppressed 85% of the umu gene expression compared to the controls at <0.73 micromol/mL, with an ID(50) value of 0.41 micromol/mL. Additionally, moscatilin was tested for its ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinoline-1-oxide (4NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), UV irradiation, 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), benzo[a]pyrene (B[a]P), and aflatoxin B(1) (AFB(1)). With all of the aforementioned chemicals or treatments, moscatilin showed a dramatic reduction in their mutagenic potential. Interestingly, moscatilin almost completely suppressed (97%) the AFB(1)-induced SOS response at concentrations <0.73 micromol/mL, with an ID(50) of 0.08 micromol/mL. Finally, the antimutagenic activities of moscatilin against furylfuramide and Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain. The results those experiments indicated that moscatilin demonstrated a dramatic suppression of the mutagenicity of only Trp-P-1 but not furylfuramide.  相似文献   

Effects of dietary Nannochloropsis sp. powder and lipids on the growth performance and fatty acid composition of larval and postlarval kuruma shrimp,Marsupenaeus japonicus     

T. O. Oswald Adissin  Ishikawa Manabu  Koshio Shunsuke  Yokoyama Saichiro  Amina S. Moss  Serge Dossou 《Aquaculture Nutrition》2020,26(1):186-200

The current study evaluated the effects of fish oil replacement with eicosapentaenoic acid‐enriched single‐cell microalgae in the diets of larval and postlarval kuruma shrimp. Experimental diets containing different level of Nannochloropsis sp. powder (10, 40, 70 g/kg) and lipids (2, 8, 10, 14, 35, 58 g/kg) were evaluated. The substitution of fish oil with algal powder significantly improved shrimp growth compared to that in the control group, with the highest final body weight recorded at 70 g/kg in larvae and 40 g/kg in postlarvae. Larvae fed algal lipids with a dry weight percentage in the diet of greater than 10 g/kg showed significantly lower performance than those in the control group. The neutral lipids in the tissue of the postlarvae that had been fed algal lipids had an improved fatty acid profile, as the content of highly unsaturated fatty acids increased compared to that in the other groups. The content of docosahexaenoic acid increased in the tissue, indicating the possible occurrence of the metabolism and accumulation of Nannochloropsis sp. essential fatty acids. Algal powder could replace FO up to 140 g/kg in shrimp diets without compromising growth and FA profiles.  相似文献   

氧化鱼油与棕榈油对花鲈肝脏抗氧化酶及组织结构的影响   总被引：7，自引：1，他引：6  

韩雨哲  姜志强  任同军  越盐俊介  高坚  石洪玥 《中国水产科学》2010,17(4)

在21个200 L圆形流水水槽中各放养花鲈(Lateolabrax maculatus)幼鱼,初始体质量为(1.73±0.01)g.在相同的环境条件下投喂以棕榈油(P)与新鲜鱼油(F)或氧化鱼油(OF)不同比例混合的7组饲料(10P,10F,6F4P,4F6P,100F,60F4P和40F6P),每个实验组设3个重复.60d饲养实验结束后,通过测定花鲈肝脏部分抗氧化酶(超氧化物歧化酶SOD,过氧化氢酶CAT和谷胱甘肽过氧化物酶GSH-Px)活力和总抗氧化能力(T-AOC),并对肝脏,肠以及肌肉进行组织学观察,研究在配合饲料中添加棕榈油替代氧化鱼油对花鲈肝脏抗氧化酶活力及其对组织结构的影响.结果表明,在含有氧化鱼油的实验组中,添加40%的棕榈油对花鲈肝脏的CAT活力以及GSH-Px活力有显著提高作用(P<0.05),对SOD活力有一定的提高效果(P>0.05),各组间总抗氧化能力差异不显著(P>0.05).新鲜鱼油组(10F,6F4P,4F6P)间抗氧化酶活力差异不显著(P>0.05).非氧化组花鲈肝脏和肌肉组织结构完整,100F组花鲈肝脏和肌肉组织呈现氧化脂肪中毒症状,添加棕榈油后(60F4P和40F6P)症状减轻,各组花鲈肠结构无明显差异.由此认为,棕榈油在花鲈饲料中部分替代鱼油是可行的,另外,在贮存不当的饲料中,后喷涂一定比例的棕榈油能对其毒性产生缓解作用.  相似文献