Hypoxic conditions induce centrum defects in red sea bream Pagrus major (Temminck and Schlegel)     

Yoshifumi Sawada  Manabu Hattori  Naoko Sudo  Keitaro Kato  Yasuaki Takagi  Kazuhiro Ura  Michio Kurata  Tokihiko Okada  & Hidemi Kumai 《Aquaculture Research》2006,37(8):805-812

A previous study elucidated that an extreme hypoxia during somitogenesis induced the most frequent skeletal malformation centrum defects in red sea bream (RSB), Pagrus major. In this study, details of the hypoxic conditions to induce them in RSB, dissolved oxygen (DO) concentration and exposure time to hypoxia, were investigated. Fertilized eggs were exposed to seawater of six DO concentrations (0%, 10%, 25%, 50%, 75% and 100% of saturation) for seven different periods (5, 10, 30, 60, 120, 240 and 360 min) during somitogenesis. Somitic disturbances in newly hatched larvae were induced by exposure to 0% and 10% DO concentration for 10 and 120 min and longer respectively. Rearing eggs exposed to hypoxic condition of 10% DO for 240 min for 40 days post‐hatch showed that the location and the frequency of somitic disturbances in larvae and centrum defects in juveniles were significantly correlated (P<0.01). Dissolved oxygen concentration of the interstitial water in the egg high density layer formed at the water surface in a stationary state abruptly decreased to 3.7% within 7 min. Centrum defect induction by exposure of eggs to extreme low DO concentrations for a short period, which is the probable situation in the practical juvenile production, suggests that careful maintenance of DO concentration is important in the incubating water of fertilized eggs during egg sorting and transportation, where eggs are made into a pile and undergo hypoxia, for the prevention of centrum defects.  相似文献   

Changes in the scotopic vision of juvenile Pacific bluefin tuna (Thunnus orientalis) with growth     

Matsumoto T  Okada T  Sawada Y  Ishibashi Y 《Fish physiology and biochemistry》2011,37(3):693-700

In cultured juvenile Pacific bluefin tuna (Thunnus orientalis), reducing the mass deaths caused by collision or contact with tank or net walls at night is a priority for seedling production. Pacific bluefin tuna is a visually dependant species, although its scotopic vision is poor. We recorded electroretinograms to investigate the visual function with growth in the dark-adapted eyes of juvenile Pacific bluefin tuna. Peak wavelengths of spectral sensitivity [38–62 days posthatch (dph), 77–167 mm standard length (SL)] were observed between 474 and 494 nm. Visual light sensitivity has a tendency to increase slightly with growth at 28–64 dph in individuals that measured 29–175 mm SL. However, visual temporal resolution did not significantly increase with growth at 38–62 days dph in individuals that measured 77–167 mm SL. These results suggest that the mass death continues between 28 and 64 dph because of low visual function and increasing swimming speed with growth.  相似文献   

Oxygen deficiency during somitogenesis causes centrum defects in red sea bream, Pagrus major (Temminck et Schlegel)     

Manabu Hattori  Yoshifumi Sawada  Michio Kurata  Shinji Yamamoto  Keitaro Kato  & Hidemi Kumai 《Aquaculture Research》2004,35(9):850-858

Vertebral deformities in red sea bream, Pagrus major, remain serious obstacles to the improvement of seedling quality for its aquaculture. However, the causalities of the deformities remain unclear and prevention methods have not yet been established. In this paper, oxygen deficiency during somitogenesis was demonstrated to cause centrum defects (formerly called fused vertebrae in many cases), which are the major vertebral deformity in cultured red sea bream. An induction experiment of centrum defects was conducted by placing fertilized red sea bream eggs under low dissolved oxygen conditions (10.3–16.6%). The low oxygen treatment was carried out for five different developmental stages of embryo: two‐cell stage to blastula stage; gastrula stage; three to 10 somites stage; 11–17 somites stage and 18–24 somites stage. Oxygen deficiency during somitogenesis induced a high incidence of centrum defects. In contrast, it hardly induced centrum defects during the other stages. The dissolved oxygen concentration in the rearing water should be carefully regulated for fertilized eggs, especially during somitogenesis to reduce the incidence of vertebral deformities in the red sea bream.  相似文献   

Japanese star anise ringspot-associated virus is a distinct emaravirus transmitted by the eriophyid mite (the family Diptilomiopidae)     

Shimomoto  Yoshifumi  Okada  Tomoyuki  Ikeda  Kenichi  Tatara  Akio  Hasegawa  Yusuke  Yanagisawa  Hironobu  Takeyama  Sawana  Hayashi  Kazusa  Yano  Kazutaka  Morita  Yasuaki  Kubota  Kenji 《Journal of General Plant Pathology》2022,88(1):69-80

Japanese star anise (Illicium anisatum L., JSA) is seriously damaged by a ringspot disease in Japan. Herein, to determine the causal agent using high-throughput sequencing, we discovered viral RNAs associated with JSA ringspot disease. We then determined the complete or near-complete nucleotide sequences of these RNAs using Sanger sequencing and RACE. The complementary strand of viral RNAs 1, 2, 3, 4, and 5 encoded a single protein, which shared sequence identity with P1 (RNA-dependent RNA polymerase), P2 (glycoprotein precursor), P3 (nucleocapsid protein), P4 (movement protein), and a protein with unknown function of emaraviruses (genus Emaravirus), respectively; however, the highest amino acid sequence identity for the P1–P5 proteins between JSARaV and known emaraviruses was 41.9%, 30.0%, 30.1%, 52.2%, and 38.0%, respectively, all of which were lower than the species demarcation criterion. Furthermore, RNA segments harbored conserved 12-nt terminal sequences at the 5′- and 3′-termini, and a high complementarity of approximately 20 nt in 5′- and 3′-terminal sequences. Transmission electron microscopy confirmed the presence of virus-like particles. JSA ringspot disease was found to be transmitted by an eriophyid mite (subclass Acari, superfamily Eriophyoidea) that belongs to the family Diptilomiopidae. Taken together, these results identified the virus responsible for the ringspot disease of JSA as a new member of the genus, Emaravirus, which we named as the Japanese star anise ringspot-associated virus (JSARaV). Moreover, this is the first report noting that eriophyid mites of the family Diptilomiopidae are capable of transmitting emaravirus.

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Effect of hinoki (Chamaecyparis obtusa) wood-wool in tatami mat on the activity of house dust mite Dermatophagoides pteronyssinus     

Yasushi Hiramatsu  Naoyuki Matsui  Tatsuro Ohira  Yasunori Imai  Yoshifumi Miyazaki 《Journal of Wood Science》2006,52(4):353-357

To suppress the activity of house dust mites in tatami mats, where they tend to breed, a tatami mat consisting of hinoki (Chamaecyparis obtuse) wood-wool was prepared. The suppressive effect of hinoki wood-wool on house dust mites (Dermatophagoides pteronyssinus) was then measured. To investigate the effective period of the wood-wool on the mites, 5-day exposure tests were conducted every few weeks for a total of 52 weeks. In the tests of the first and sixth weeks, the activity of the mites was strongly suppressed, and no walking or moving mite was found after 5 days of exposure. The suppressive effect on mites was maintained for 52 weeks. It was concluded that using hinoki wood-wool to produce tatami mats is an effective method of suppressing the activity of mites for about 1 year.  相似文献   

Effect of softwood thin veneers in tatami on the activity of the house dust mite Dermatophagoides pteronyssinus     

Takahiro Mori  Yoshifumi Miyazaki 《Journal of Wood Science》2002,48(2):163-164

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A practical and convenient synthesis of hotrienol,an excellent fruity smelling compound     

Yuasa Y  Kato Y 《Journal of agricultural and food chemistry》2003,51(14):4036-4039

The practical and convenient synthesis of hotrienol, which is an excellent fruity smelling compound, has been performed by the ene-type chlorination of linalyl acetate and then dehydrochlorinated by lithium bromide and lithium carbonate in DMF, followed by hydrolysis in three steps with an overall yield of 55%.  相似文献   

ORIGINAL ARTICLE     

Tomoko NAKANO  Wataru TAKEUCHI  Gen INOUE  Masami FUKUDA  Yoshifumi YASUOKA 《Soil Science and Plant Nutrition》2006,52(1):77-88

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Changes in the concentrations of bioactive compounds in plantain leaves     

Tamura Y  Nishibe S 《Journal of agricultural and food chemistry》2002,50(9):2514-2518

The plantain is used in herbal medicines and for pasturage. Two cultivars of plantain (Plantago lanceolata L.), Grasslands Lancelot and Ceres Tonic, were sown in spring. Changes in catalpol, aucubin, and acteoside concentrations in the leaves during the growing season and by drying after harvesting were quantitatively determined by high-performance liquid chromatography. The concentration of catalpol was relatively low, fluctuating between 1 and 2% of dry matter during the growing season, and there was no clear-cut seasonal change. From spring to midfall, the aucubin concentration increased from 2.1 to 4.8% in Grasslands Lancelot and from 1.0 to 2.7% in Ceres Tonic. These increases were gradual over the season, except for during midsummer, when aucubin concentrations were relatively constant. The acteoside concentration increased from 3.4 to 7.1% in Grasslands Lancelot and from 1.5 to 4.1% in Ceres Tonic over the course of the growing season, although in the summer it declined steadily to lows of 2.5% in Grasslands Lancelot and 1.9% in Ceres Tonic. Our data suggested that midfall was the appropriate time for harvesting plantain for medicinal use. The concentrations of the bioactive compounds steadily decreased in the initial stages of drying both under natural climatic conditions and at 60 degrees C. The development of processing methods to minimize the loss of bioactive compounds is imperative.  相似文献   

Mortality of Northern Bluefin Tuna Thunnus thynnus Due to Trauma Caused by Collision During Growout Culture     

Shigeru  Miyashita Yoshifumi  Sawada Nobuhiro  Hattori Hiromu  Nakatsukasa Tokihiko  Okada Osamu  Murata Hidemi  Kumai 《Journal of the World Aquaculture Society》2000,31(4):632-639

Abstract.— Indoor and outdoor experiments were conducted to improve the rearing techniques for artificially hatched northern bluefin tuna Thunnus thynnus during growout culture. Collisions with the walls of tanks or nets caused mass mortality that occurs during growout. The period when collisions frequently occur and the types of injury caused by collision were examined in this study. Juveniles were reared in indoor tanks from 30 to 120 d after hatching, and in an open sea net cage from 42 to 150 d after hatching. Dead fish were collected and counted daily in both of the experiments. In the indoor experiment, the sampled fish were preserved in 10% formalin solution, and each of 10 specimens of about 30, 50, 70, 85, 100, 130, 160 and 225 mm in body length (BL) were examined using x‐rays to detect injury of the bones. Juvenile and young adult bluefin tuna showed a reduction in numbers caused by collision with the tank or the net wall during the experiments. In the indoor tank, there were 1,200 fish on day 30 but only eight on day 120. The daily mortality increased from day 30 after hatching, when juveniles reached 50‐mm BL and remained over 4%/d until day 60 when juveniles grew to 300‐mm BL. The proportion of dead fish with injuries of bone, especially of the vertebral column and the parasphenoid, increased after fish reached 50‐mm BL, and exceeded 60% in fish with BL 85 mm or greater. In the open sea net cage, there were 3,841 fish at the start of the experiment on day 42 and only 65 on day 150. In this experiment, the reduction was greatest from the start of the experiment until day 80, when fish grew to approximately 25 cm in total length. Significant bacterial, viral or parasitic diseases were not observed in these fish; the only findings were dislocations of the vertebral column and injuries to the upper and lower jaws. These results show that the loss of juvenile and young adult bluefin tuna was caused by collision with the tank or net wall that fatally damaged the bones of the vertebral columns and the parasphenoid.  相似文献