Changes in the expression of pituitary gonadotropin subunits during reproductive cycle of multiple spawning female chub mackerel Scomber japonicus     

Nyuji M  Selvaraj S  Kitano H  Ohga H  Yoneda M  Shimizu A  Kaneko K  Yamaguchi A  Matsuyama M 《Fish physiology and biochemistry》2012,38(3):883-897

The endocrine regulation of reproduction in a multiple spawning fish with an asynchronous-type ovary remains largely unknown. The objectives of this study were to monitor changes in the mRNA expression of three gonadotropin (GtH) subunits (GPα, FSHβ, and LHβ) during the reproductive cycle of the female chub mackerel Scomber japonicus. Cloning and subsequent sequence analysis revealed that the cDNAs of chub mackerel GPα, FSHβ, and LHβ were 658, 535, and 599 nucleotides in length and encoded 117, 115, and 147 amino acids, respectively. We applied a quantitative real-time PCR assay to quantify the mRNA expression levels of these GtH subunits. During the seasonal reproductive cycle, FSHβ mRNA levels remained high during the vitellogenic stages, while GPα and LHβ mRNA levels peaked at the end of vitellogenesis. The expression of all three GtH subunits decreased during the post-spawning period. These results suggest that follicle-stimulating hormone (FSH) is involved in vitellogenesis, while luteinizing hormone (LH) functions during final oocyte maturation (FOM). Both GPα and FSHβ mRNA levels remained high during the FOM stages of the spawning cycle and increased further just after spawning. Thus, FSH synthesis may be strongly activated just after spawning to accelerate vitellogenesis in preparation for the next spawning. Alternatively, LHβ mRNA levels declined during hydration and then increased after ovulation. This study demonstrates that chub mackerel are a good model for investigating GtH functions in multiple spawning fish.  相似文献   

A New Dibenz[b,e]oxepine Derivative, 1-Hydroxy-10-methoxy-dibenz[b,e]oxepin-6,11-dione,from a Marine-Derived Fungus,Beauveria bassiana TPU942     

Hiroyuki Yamazaki  Henki Rotinsulu  Tsuyoshi Kaneko  Kazuki Murakami  Hiromu Fujiwara  Kazuyo Ukai  Michio Namikoshi 《Marine drugs》2012,10(12):2691-2697

1-Hydroxy-10-methoxy-dibenz[b, e]oxepin-6,11-dione (1) was obtained from the culture broth of a marine-derived fungus, Beauveria bassiana TPU942, isolated from a marine sponge collected at Iriomote Island in Okinawa, together with two known compounds, chrysazin (2) and globosuxanthone A (3). The structure of 1 was elucidated on the basis of its spectroscopic data (HREIMS, 1D and 2D NMR experiments including ¹H–¹H COSY, HMQC and HMBC spectra). Dibenz[b, e]oxepines are rare in nature, and only six natural products have been reported. Therefore, compound 1 is the seventh natural product in this class. Compounds 2 and 3 showed an antifungal activity against Candida albicans, and 3 inhibited the cell growth against two human cancer cell lines, HCT-15 (colon) and Jurkat (T-cell lymphoma). Compound 1 did not show an apparent activity in the same bioassays.  相似文献   

Timing to promote initial swimbladder inflation by surface film removal in Pacific bluefin tuna,Thunnus orientalis (Temminck and Schlegel), larvae          下载免费PDF全文

Michio Kurata  Manabu Seoka  Yasunori Ishibashi  Tomoki Honryo  Shigeru Katayama  Kenji Takii  Hidemi Kumai  Shigeru Miyashita  Yoshifumi Sawada 《Aquaculture Research》2015,46(5):1222-1232

This study investigated the optimal timing of day to promote initial swimbladder inflation (ISI) for improved Pacific bluefin tuna (PBT), Thunnus orientalis, larval survival. Larval swimbladder inflation frequency was compared based on three experiments using different time schemes of surface film removal (SFR) from 3 to 9 days post hatch (dph). SFR was conducted from 05:00 to 19:00 hours (light period: S.5–19), 19:00 to 05:00 hours (dark period: S.19–5), 08:00 to 19:00 hours (S.8–19) and the entire day (S.24) in Experiment 1; from 08:00 to 19:00 hours (S.8–19‐E2), 08:00 to 13:00 hours (S.8–13), 13:00 to 19:00 hours (S.13–19) in Experiment 2; and from 13:00 to 16:00 hours (S.13–16), 16:00 to 19:00 hours (S.16–19), 18:00–19:00 hours (S.18–19) in Experiment 3. The swimbladder inflation frequency at the experiment termination (9 dph) was significantly higher (P < 0.001) in S.24 (91.1 ± 5.7%), S.5–19 (92.2 ± 5.1%) and S.8–19 (93.3 ± 3.4%) than in S.19–5 (11.1 ± 5.1%) in Experiment 1, and remarkably higher in S.8–19‐E2 (81.7%) and S.13–19 (88.3%) than in S.8–13 (0.0%) in Experiment 2, and significantly higher (P < 0.001) in S.16–19 (84.4 ± 5.1%) and S.18–19 (70.0 ± 12.0%) than in S.13–16 (7.8 ± 3.9%) in Experiment 3. These results suggest that the optimal timing to promote larval ISI by SFR is a few hours before the end of light period (16:00–19:00 hours) from 3 to 9 dph.  相似文献   

Influence of initial swimbladder inflation failure on survival of Pacific bluefin tuna,Thunnus orientalis (Temminck and Schlegel), larvae     

Michio Kurata  Yasunori Ishibashi  Kenji Takii  Hidemi Kumai  Shigeru Miyashita  Yoshifumi Sawada 《Aquaculture Research》2014,45(5):882-892

This study investigated the influence of initial swimbladder inflation (ISI) failure on survival of Pacific bluefin tuna (PBT), Thunnus orientalis, larvae to prevent mass mortality due to sinking death. In Experiment 1, swimbladder inflation frequency and survival within an ISI promoted (PS) group, for which surface film of rearing water was removed, and a group without ISI promotion (NPS) were compared in 20 and 30 kL tanks. The PS group demonstrated significantly higher swimbladder inflation frequency and increased survival than the NPS group within 20 kL tanks at 9 days post hatching (dph). Similar tendencies were observed within 30 kL tanks. In Experiment 2, larval distribution and swimbladder inflation frequency in the night‐time were examined through larval sampling within the upper and middle layers of the water column and tank bottom within 1.6 and 30 kL tanks at 5 dph. Larvae at tank bottom had higher distributional density and significantly lower swimbladder inflation frequency than those distributed in the upper and middle layers within 1.6 kL tanks. Similar tendencies were observed within 30 kL tanks. Results of this study suggest the improvement of larval survival due to prevention of sinking death through ISI promotion in mass‐scale PBT larviculture.  相似文献   

Seasonal Deposition Fluxes of Polycyclic Aromatic Hydrocarbons (PAHs) in Lake Biwa,Japan     

Tamamura  Shuji  Sato  Tsutomu  Ota  Yukie  Aota  Yasuaki  Kashiwaya  Kenji  Kumagai  Michio 《Water, air, and soil pollution》2009,196(1-4):297-309

Water, Air, & Soil Pollution - The concentrations of Cd, Cu, Fe, Ni, Pb and Zn in the different parts of six bivalves species were determined. From the study conducted, it was found that the...  相似文献   

Effects of Culture Media and Light Intensity on in vitro Growth of Oncidium under CO2 Enrichment Condition     

HeSonglin PanHuitang YangQiusheng KongDezheng ZhangQixiang MichioTanaka 《中国林学(英文版)》2003,5(3):28-32

The effects of culture media and light intensity on in vitro growth of Oncidium ‘Aloha Iwanga‘ were investigated under CO2 enrichment condition. Height, fresh and dry weight of the Oncidium seedlings were measured, and the leaf number per plant, shoot number per plant, leaf width and leaf chlorophyll content were also investigated. The results were as follows: 1) The seedling height, fresh and dry weight, leaf number per plant, leaf width and leaf chlorophyll content of the shoots growing on MS complete culture medium were higher than those on 1/2MS, VW and 1/2VW media. The root number per plant and ratio of dry matter of the seedlings cultured on 1/2MS and 1/2VW media were higher than those on MS and VW; 2) The seedling height, flesh weight, dry weight, dry matter ratio and leaf chlorophyll content, leaf length, leaf width, root length, leaf number per plant, root number per plant of seedlings of Oncidium growing under 4 500 lx and 1 700 lx were higher than those under 750 lx. However, there was no significant difference in those growth parameters mentioned above while dealing with 4 500 lx and 1 700 lx except for the seedling height. Nevertheless, the leaf color of plants under 4 500 lx was lighter and the leaves of the lower parts became yellowish in comparison with those growing under 1 700 lx.  相似文献   

Stock structure and resource management of hairtail <Emphasis Type="Italic">Trichiurus japonicus</Emphasis> based on seasonal broods around the Bungo Channel,Japan     

Shingo Watari  Syunji Tokumitsu  Taro Hirose  Michio Ogawa  Mitsutaku Makino 《Fisheries Science》2017,83(6):865-878

Declines in landings of the hairtail Trichiurus japonicas indicate the need for more effective management of this species. Hairtail spawning peaks occur twice yearly in the Bungo Channel, in spring and autumn. Relationships between hairtail stock and brood seasonality were examined to determine if an association between either and a decline in landings existed. Stock assessments show that the biomass of both spring and autumn hairtail broods from within and around the Bungo Channel are decreasing, with a rapid reduction in spring-brood stock abundance after 2007 largely responsible for decreased landings. Yield and spawning per recruitment analyses indicate current fishing pressure to be higher than several reference points. We suggest that fishing pressure needs to be reduced by at least 20% of the current level for this fishery to remain sustainable, as the projected stock abundance and catch demonstrate that the current fishing pressure is unsustainable. Analysis of time-series data of recruits per spawning revealed spring-brood recruitment to have been strong in year classes 2003 and 2005. Of various options available for improved management of this fishery, we propose that fishing pressure should be reduced in the years following the appearance of strong year classes to increase future biomasses and landings.  相似文献   

M. Ichinari,M. Masuko,H. Takenaka,R. Hasegawa,T. Ichiba,Y. Hayase and R. Takeda, ‘Structure and fungicidal activities of methoxyiminophenylacetamide derivatives’. Pesticide Science 55(3) 1999, 347–349     

Mitsuhiro Ichinari  Michio Masuko  Hideyuki Takenaka  Riichi Hasegawa  Tsuneo Ichiba  Yoshio Hayase  Reiji Takeda 《Pest management science》1999,55(9):962-962

The original article to which this Correction refers was published in Pesticide Science 55 (3) 1999, 347–349. © 1999 Society of Chemical Industry  相似文献   

Influence of Polyunsaturated Fatty Acid Intake on Kidney Functions of Rats with Chronic Renal Failure     

Hiroki Muramatsu  Naoe Akimoto  Michio Hashimoto  Kenji Sugibayashi  Masanori Katakura 《Marine drugs》2021,19(12)

Arachidonic acid (ARA), an omega-6 (ω-6) polyunsaturated fatty acid (PUFA), is involved in the development and maintenance of renal functions, whereas docosahexaenoic acid (DHA) is an omega-3 (ω-3) PUFA that has anti-inflammatory effects and attenuates nephropathy. However, their effects on the progression of chronic kidney disease (CKD) remain unknown. The aim of this study was to assess the effects of feeding ARA, DHA, and ARA and DHA-containing diets on rats with 5/6 nephrectomized kidneys. Urine and feces were collected every 4 weeks, and the kidneys were collected at 16 weeks after surgery. Urinary albumin (U-ALB) excretion increased gradually with nephrectomy, but the U-ALB excretion was attenuated by feeding the rats with an ARA + DHA-containing diet. Reactive oxygen species (ROS) levels in the kidneys were lower in the ARA + DHA group than in the other groups. At 4 weeks after surgery, the lipid peroxide (LPO) levels in the plasma of the ARA + DHA groups decreased significantly after surgery compared to the control CKD group, but this did not happen at 16 weeks post-surgery. There was a significant negative correlation between LPO levels in the plasma at 4 weeks and creatinine clearance, and a positive correlation with urinary albumin levels. These results suggest that the combination of ARA and DHA inhibit the progress of early stage CKD.  相似文献   

Isolation and characterization of an additional crustacean hyperglycemic hormone from the greasyback shrimp <Emphasis Type="Italic">Metapenaeus ensis</Emphasis>     

Tsuyoshi Ohira  Katsuyoshi Suitoh  Fumihiro Yamane  Chiaki Nagai  Michio Suzuki  Naoaki Tsutsui  Hiromichi Nagasawa  Susumu Izumi 《Fisheries Science》2010,76(4):605-611

Crustacean hyperglycemic hormone (CHH) is released from the X-organ/sinus gland complex located in the eyestalks. In this study, the most abundant CHH in the sinus gland of the greasyback shrimp Metapenaeus ensis was purified by reversed-phase HPLC and identified by N-terminal amino acid sequencing. Although two CHH molecules (Mee-CHH-A and Mee-CHH-B) have already been identified from M. ensis by cDNA cloning, this study revealed the presence of an additional CHH peptide based on differences in the N-terminal amino acid sequences of the CHH-A and CHH-B. Therefore, this novel CHH was designated as Mee-CHH-C. A cDNA encoding the Mee-CHH-C precursor was cloned by RT-PCR coupled with 5′- and 3′-RACE, and it was found that the mature Mee-CHH-C consisted of 72 amino acid residues containing 6 conserved cysteine residues and possessed an amidated C terminus. Mee-CHH-C had 62 and 68% identities with Mee-CHH-A and Mee-CHH-B, respectively, and was highly homologous to CHHs characterized from other penaeid shrimp species. The hyperglycemic activity of Mee-CHH-C was examined by an in vivo bioassay using the kuruma prawn Marsupenaeus japonicus. Injection of Mee-CHH-C increased hemolymph glucose levels significantly and dose-dependently. These results indicate that Mee-CHH-C is possibly one of the major molecules in M. ensis that regulate glucose levels in the hemolymph.  相似文献