Effect of Illuminance Transition Rate on Survival of Juvenile Pacific Bluefin Tuna,Thunnus orientalis     

Tomoki Honryo  Michio Kurata  Tokihiko Okada  Yoshifumi Sawada  Yasunori Ishibashi 《Journal of the World Aquaculture Society》2014,45(5):523-531

To investigate the reason for the high mortality of cultured juvenile Pacific bluefin tuna (PBT), especially during land‐based culture, we examined the effect of the rate of light‐intensity change during the dawn period. Juvenile PBT kept in a natural light environment (control) were compared with those exposed to an artificially slowed change in light intensity during the dawn period (test group). For the test group, lamps, which were connected to automatic timers and placed above the rearing tank, were switched on from 0345 to 0515 h at 15‐min intervals. After 9 d, the survival rate of the test and control group was identical. Between Day 1 and Day 6, whole‐body cortisol levels were not different between groups. However, whole‐body glucose levels in the test group were significantly higher than those in the control group. Both groups displayed a diel rhythm in plasma cortisol concentration that peaked at 0300–0600 h. These results suggest that slowing the increase in light intensity during the dawn period did not improve survival and that low light intensity itself induces high mortality in cultured PBT juveniles.  相似文献   

Gonadal morphogenesis and sex differentiation in cultured chub mackerel,Scomber japonicus     

Toru Kobayashi  Ryo Ishibashi  Shinji Yamamoto  Satoshi Otani  Koichi Ueno  Osamu Murata 《Aquaculture Research》2011,42(2):230-239

The timing of primordial germ‐cell (PGC) migration with regard to the gonadal anlagen, gonad formation and sex differentiation was examined histologically in the chub mackerel (Scomber japonicus) at 5–190 days post hatching (dph). At 5 dph, PGCs appeared on the peritoneal epithelium surface or in the mesentery, on the dorsal side of the abdominal cavity. By 10 dph, stromal cells around the PGCs proliferated. The gonadal primordium was formed by 15 dph. The gonadosomatic index was 0.01% at 30 dph and increased thereafter (0.32% in females and 0.04% in males at 160 dph). Ovarian differentiation occurred at 30–40 dph, indicated by ovarian cavity formation (elongation and fusion of the upper and lower ovarian edges). Meiosis was subsequently initiated. A few meiotic oocytes surrounded the cavity at 50 dph; most were in the perinucleolus stage at 60 dph and attained a diameter of 60–70 μm at 190 dph. Testicular differentiation occurred at 30 dph, indicated by the formation of the sperm duct primordium. Spermatogonia gradually proliferated, developing into spermatocytes at the chromatin–nucleolus stage (after 90 dph) and subsequently into spermatids and spermatozoa (160 dph). These data could aid the development of seeding and cell‐engineering technologies for scombrid fish.  相似文献   

Hypocholesterolemic effect of blue-green alga,ishikurage (Nostoc commune) in rats fed atherogenic diet     

Kohji Hori  Genji Ishibashi  Takuo Okita 《Plant foods for human nutrition (Dordrecht, Netherlands)》1994,45(1):63-70

Nutritional quality of the castor meal protein isolate detoxified using boiling and lime cum heat treatments was evaluated in experiments with rats. Chemical scores of both the treated isolates were similar, threonine being the first limiting amino acid. The calculated nutritional indices (essential amino acid index) and PER were higher for the boiled isolate (1.3) than that was for lime-cum-heat treated (0.86). Though, necropsy examination of organs did not reveal any abnormalities, histopathological changes were observed in the organs — liver, kidney, intestine that could be attributed to the deficiency of essential amino acids in the detoxified castor protein isolates.  相似文献   

Polymerase chain reaction (PCR) for the detection of herpesvirus in tortoises     

Une Y  Murakami M  Uemura K  Fujitani H  Ishibashi T  Nomura Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(8):905-907

A polymerase chain reaction (PCR)-based method using a herpesvirus consensus primer was assessed for the identification of herpesviral infections in tortoises. A single band of about 230 bp was detected in PCR products from two out of twenty swabs taken from the oral cavity, three out of three paraffin-embedded tissue sections from the liver (two cases) and oral mucosa (one case), and one out of two fresh tissue samples from the oral mucosa. Nucleotide sequencing of these PCR products indicated that the herpesvirus present in these tortoises might belong to the alphaherpesvirinae. PCR using swabs and biopsy tissues was a sensitive and highly specific method for the diagnosis of herpesviral infections in tortoises.  相似文献   

基于Lefkovitch矩阵模型的山酢浆草种群动态分析     

尤海梅  小池文人 《浙江林学院学报》2011,28(1):66-71

依据林下多年生草本植物山酢浆草Oxalis griffithii的形态学特征,将其生活史划分为4个阶段,并根据3种生境下山酢浆草种群的野外调查资料建立了不同种群的Lefkovitch结构矩阵模型,在此基础上预测了山酢浆草种群的动态及其阶段结构的变化;同时,运用敏感度、贡献率指标分析了影响种群动态的关键生活史阶段。结果表明：不同生境下山酢浆草种群的动态发展趋势不尽相同,常绿阔叶林下的种群（MD）呈稳定发展状态,其他2种生境下种群表现出衰退的发展趋势;种群的动态变化过程受个体的生长、残存、萎缩和繁殖等的综合影响;不同生活史阶段对种群动态的影响差异显著,种群动态过程及其发展趋势主要受种群内较大阶段个体的影响。图2表5参19  相似文献   

Changes in the retinal cone density distribution and the retinal resolution during growth of juvenile Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>     

Shinsuke Torisawa  Tsutomu Takagi  Yasunori Ishibashi  Yoshifumi Sawada  Takeshi Yamane 《Fisheries Science》2007,73(5):1202-1204

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Biosynthesis of agr-Ecdysone by Prothoracic Glands in vitro     

Chino H  Sakurai S  Ohtaki T  Ikekawa N  Miyazaki H  Ishibashi M  Abuki H 《Science (New York, N.Y.)》1974,183(4124):529-530

An in vitro study in which isolated prothoracic glands of the Bombyx silkworm were cultured has provided definite evidence that the prothoracic gland is the site where molting hormone is synthesized. The hormone behaved very similarly to free ecdysone on thin-layer chromatography. Analysis by liquid chromatography and mass fragmentography revealed that the hormone is identical with alpha-ecdysone.  相似文献   

Diet-induced hypercholesterolemia in mice: prevention by overexpression of LDL receptors   总被引：22，自引：0，他引：22  

M Yokode  R E Hammer  S Ishibashi  M S Brown  J L Goldstein 《Science (New York, N.Y.)》1990,250(4985):1273-1275

The current studies were designed to determine whether chronic overexpression of low density lipoprotein (LDL) receptors in the liver would protect mice from the increase in plasma LDL-cholesterol that is induced by high-fat diets. A line of transgenic mice was studied that express the human LDL receptor gene in the liver under control of the transferrin promoter. When fed a diet containing cholesterol, saturated fat, and bile acids for 3 weeks, the transgenic mice, in contrast to normal mice, did not develop a detectable increase in plasma LDL. The current data indicate that unregulated overexpression of LDL receptors can protect against diet-induced hypercholesterolemia in mice.  相似文献   

Incipient space weathering observed on the surface of Itokawa dust particles     

Noguchi T  Nakamura T  Kimura M  Zolensky ME  Tanaka M  Hashimoto T  Konno M  Nakato A  Ogami T  Fujimura A  Abe M  Yada T  Mukai T  Ueno M  Okada T  Shirai K  Ishibashi Y  Okazaki R 《Science (New York, N.Y.)》2011,333(6046):1121-1125

The reflectance spectra of the most abundant meteorites, ordinary chondrites, are different from those of the abundant S-type (mnemonic for siliceous) asteroids. This discrepancy has been thought to be due to space weathering, which is an alteration of the surfaces of airless bodies exposed to the space environment. Here we report evidence of space weathering on particles returned from the S-type asteroid 25143 Itokawa by the Hayabusa spacecraft. Surface modification was found in 5 out of 10 particles, which varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles exist in a thin (5 to 15 nanometers) surface layer on olivine, low-Ca pyroxene, and plagioclase, which is suggestive of vapor deposition. Sulfur-free Fe-rich nanoparticles exist deeper inside (<60 nanometers) ferromagnesian silicates. Their texture suggests formation by metamictization and in situ reduction of Fe(2+).  相似文献   

Chemical aspects of mutagen formation by sorbic acid-sodium nitrite reaction     

M Namiki  T Osawa  H Ishibashi  K Namiki  K Tsuji 《Journal of agricultural and food chemistry》1981,29(2):407-411

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