Seed abortion of ‘Tosa-Buntan’ pummelo pollinated with soft-X-irradiated pollens     

Tsuneo Ogata  Tomoya Takeichi  Kazunori Matsunaga  Kojiro Hasegawa  Shinzo Yamane  Keita Sugiyama 《Scientia Horticulturae》2008

Cross-pollination was performed with soft-X-irradiated hyuga-natsu pollens (1000 Gy) for ‘Tosa-Buntan’ pummelo (Citrus grandis (L.) Osbeck). This resulted in the transformation of large and complete seeds into small and empty ones (practically seedless). Although fruit set, fruit retention, total soluble solids content (TSS) and titratable acidity of the juice were not affected, decrement in the fruit size was observed. Two weeks after the pollination, endosperm cell division with free nuclei began in both the non-irradiated and irradiated pollen treatment conditions. Seven weeks after pollination, endosperm division with the cell wall occurred in the non-irradiated pollen treatment conditions; however, the endosperm development ceased in most ovules that underwent the irradiated pollen treatment, and the ovules remained in their free nuclear stage. The delayed degeneration of the ovules, following successful fertilization and commencement of endosperm cell division, allow these seedless fruits to be categorized as pseudo-parthenocarpic.  相似文献   

Contributions of the lipopolysaccharide outer core oligosaccharide region on the cell surface properties of Pseudomonas aeruginosa     

Yokota S  Fujii N 《Comparative immunology, microbiology and infectious diseases》2007,30(2):97-109

We have characterized the cell surface properties of three mutant series of Pseudomonas aeruginosa that show various defects in their lipopolysaccharide (LPS) core region. The deepest rough mutants of each series used in this study lacked completely rhamnose and glucose, and contained only galactosamine and alanine as LPS outer core constituents. However, rough mutants other than the deepest rough mutants showed high cell surface hydrophobicity compared to the corresponding parental strains, the deepest rough mutants showed less hydrophobicity than other rough mutants. The reactivity of an anti-lipid A monoclonal antibody with the deepest rough mutants was markedly higher than that with other counterparts. The deepest rough mutants tended to be more susceptible to antibiotics, such as gentamicin and polymyxin B, than the corresponding parental strains and other rough mutants. The above evidence indicates that neutral sugar, namely rhamnose and glucose, residues of the LPS outer core region play a critical role in the cell surface properties of P. aeruginosa.  相似文献   

Study on sheet material made from zephyr strands V: Properties of zephyr strand board and zephyr strand lumber using the veneer of fast-growing species such as poplar   总被引：1，自引：0，他引：1  

Yu-Jung Kim  Motoaki Okuma  Toshimine Yokota 《Journal of Wood Science》1998,44(6):438-443

Zephyr strand board (ZSB) and zephyr strand lumber (ZSL) were produced using zephyr made from poplar veneer to investigate the greater utilization of low-density poplar as a structural material. These materials were then compared to ordinary plywood, laminated veneer lumber (LVL) from poplar veneer, lauan plywood, and particleboard. The bending properties (moduli of rupture and elasticity) of ZSB proved superior to those of poplar plywood: and ZSL produced from poplar veneer zephyr had bending properties greater than ordinary LVL from poplar veneer. Apparently, the conversion of the poplar veneer into zephyr material had a positive effect on bending properties. Additionally, poplar ZSB had bending properties superior to those of lauan particleboard and equal to those of lauan plywood. The internal bond strength of poplar veneer ZSB was nearly two times greater than that of lauan particleboard.Parts of this report were presented at the international symposium on the utilization of fast-growing trees, Nanjing, China, October 1994. Report IV appeared inMokuzai Kogyo 49:599, 1994  相似文献   

Quantitative loop-mediated isothermal amplification method for the detection of <Emphasis Type="Italic">Vibrio nigripulchritudo</Emphasis> in shrimp     

Jean Fall  Gunimala Chakraborty  Tomoya Kono  Minoru Maeda  Yoshihiro Suzuki  Toshiaki Itami  Masahiro Sakai 《Fisheries Science》2011,77(1):129-134

Vibrio nigripulchritudo is considered one of the major pathogens threatening shrimp aquaculture. In this study, we developed a novel and highly specific quantitative loop-mediated isothermal amplification (Q-LAMP) assay. A set of four specific primers were designed targeting the V. nigripulchritudo intergenic spacer region. The reaction time and temperature were optimized for 60 min at 63°C. Quantitative analysis was then performed by measuring the turbidity of the reaction solution using a real-time turbidimeter, allowing for quantification of the initial DNA concentration with a sensitivity of 10² copy numbers equivalent to 2.3 colony forming units/ml or 0.3 fg/μl. The LAMP assay was able to specifically detect two representative strains of V. nigripulchritudo, whereas other Vibrio and non-Vibrio species were not amplified. A standard curve was generated for V. nigripulchritudo by plotting the threshold time (T _t) versus the log of bacterial number. A high correlation coefficient (R ² = 0.9749) was observed for the Q-LAMP reaction. In conclusion, Q-LAMP assay is a sensitive, rapid, and simple tool that can be used for the detection and quantification of V. nigripulchritudo in shrimp, thereby facilitating surveillance of vibriosis infection.  相似文献   

How to determine the appropriate mortality in experimental larval rearing?     

Tomonari Kotani  Masashi Yokota  Hiroshi Fushimi  Seiichi Watanabe 《Fisheries Science》2011,77(2):255-261

Survival in larval rearing experiments is difficult to estimate due to accidental losses and periodic sampling. The number of sampled fish can be a large proportion of the stocked ones, making it difficult to calculate the overall survival rate and mortality coefficient as this is based on the initial number. Here, a new method of calculating survival is proposed using the mortality coefficient. When the initial stocking density and sampled and final numbers are known, and assuming that mortality coefficient is constant, the final number of fishes can be represented by the formula N _t = e^−mt (N ₀ − ΣN _Sne ^mdn), where t is rearing period (days), N ₀ indicates initial number, N _t indicates the survival number at t days of rearing, m is the natural mortality coefficient, N _Sn is the sampled number in the nth sampling, and dn is the rearing period until removal of the nth sample. The provisional mortality coefficient is calculated from initial and final stocking numbers. Then values for the natural mortality coefficient are substituted into the formula with successive approximation. The coefficient, which most closely approximates the actual survival, is determined as the best fit natural mortality coefficient. Examples of larval experiments are provided to demonstrate the method and show that survival is often underestimated using traditional methods.  相似文献   

Temperature characteristics in seed germination and growth of <Emphasis Type="Italic">Zostera japonica</Emphasis> Ascherson &; Graebner from Ago Bay,Mie Prefecture,central Japan     

Mahiko Abe  Keigo Yokota  Akira Kurashima  Miyuki Maegawa 《Fisheries Science》2009,75(4):921-927

The optimal water temperature in seed germination and the upper critical water temperature in seedling growth were determined for Zostera japonica collected from Ago Bay, Japan. The relationship between the seed germination rates and seed storage period (0, 30, and 60 days) at 0°C was also examined. The optimal water temperature in seed germination was in the range 15–20°C regardless of the storage period, in which germination rates were up to 14%. Seedlings, grown from seeds up to 10 cm in total length, were cultured for 1 week at various water temperatures to measure their relative growth rates. The optimal water temperature in early growth was in the range 20–25°C; relative growth rates ranged from 3.8 to 4.2%. Seedlings could survive up to a water temperature of 29°C, but most seedlings withered at 30 or 35°C. The optimal water temperatures for seed germination and seedling growth were related to the seasonal changes of water temperature in the sampling site. Although seedlings were hardly observed in Ago Bay in summer, Z. japonica might extend its distribution as far as where the summer water temperature is lower than 29°C.  相似文献   

Preliminary study on homing,site fidelity,and diel movement of black rockfish <Emphasis Type="Italic">Sebastes inermis</Emphasis> measured by acoustic telemetry   总被引：1，自引：0，他引：1  

Hiromichi Mitamura  Keiichi Uchida  Yoshinori Miyamoto  Nobuaki Arai  Toshiharu Kakihara  Takashi Yokota  Junichi Okuyama  Yuuki Kawabata  Tohya Yasuda 《Fisheries Science》2009,75(5):1133-1140

Several species of fish exhibit strong homing ability and distinct site fidelity to their original habitats and spawning sites. We have studied the homing ability, site fidelity, and diel movement patterns of three nocturnal black rockfish Sebastes inermis. The patterns were studied by radio-linked acoustic positioning system (VRAP) and fixed monitoring receivers (VR2) in Maizuru Bay, Japan from June to July 2004. All tagged fish were displaced by 80–120 m, but they returned to their respective captured sites at dusk, regardless of the time of release. The fish tagged with a depth sensor transmitter displayed active vertical movement just after the release, and subsequently swam near the bottom depth around the captured site. After homing, they displayed small home ranges [average 815 ± 265 m² (SD)] around a single rocky area with one or two core areas (average 64 ± 30 m²). One core area was utilized during the daylight and dark periods, whereas the other was used primarily during the dark period. The depth-tagged fish primarily used the depth of the rock crevice during the daylight, and it spent its dark period between the surface and the deeper bottom depth.  相似文献   

Mechanism of the rice hull‐induced germination of Monochoria vaginalis seeds in darkness     

Takao Yokota  Hiromi Handa  Yumiko Yamada  Koichi Yoneyama  Yasutomo Takeuchi 《Weed Biology and Management》2014,14(2):138-144

The seeds of Monochoria vaginalis require light to germinate. However, they are able to germinate in darkness in the presence of rice hulls. The mechanism of this phenomenon was investigated in this study, in which only the unsterilized seeds of Monochoria were induced to germinate by the presence of a rice hull extract. The rice hull extract was able to be replaced by either a mixture of amino acids and phosphate or a yeast extract. The culture media in which germination was observed always showed turbidity, indicating the propagation of bacteria, which were identified as Bacillus sp., Pedobacter sp., Pantoea sp. and Sphingomonas sp. Treatment with the individual bacterial species or combinations of these bacteria induced Monochoria seed germination when added to the media containing the rice hull extract. It was concluded that the rice hull extract accelerates the propagation of bacteria, which in turn digest the seed coat of Monochoria, facilitating its germination.  相似文献   

Keratometry in normal cats: a cross-sectional study in Japan using an automated handheld keratometer     

Minae KAWASAKI  Tomoya FURUJO  Kazuo AZUMA  Yoshiharu OKAMOTO  Norihiko ITO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(8):1256

Keratometry was performed in 73 domestic cats of varied signalment in Japan using an automated handheld keratometer. The mean corneal curvature radius was significantly lower for cats younger than 1 year than for those older than 2 years (8.04 mm vs. 8.80−8.99 mm, P<0.01). The radius was significantly greater in males than in females among the cats older than 11 years (9.22 mm vs. 8.84 mm, P=0.01), while the age distributions of the males and females were similar. Corneal astigmatism did not significantly differ across the gender and age groups. The predictability of the corneal curvature and astigmatism was approximately 41−43% and less than 3%, respectively, as a function of age and bodyweight. The results highlighted some age- and sex-related keratometric variations in domestic cats in Japan.  相似文献   

Immunostimulatory effects of natural human interferon-alpha (huIFN-α) on carps Cyprinus carpio L.     

Hironobu Watanuki  Gunimala Chakraborty  Hiroki Korenaga  Tomoya Kono  R.B. Shivappa  Masahiro Sakai   《Veterinary immunology and immunopathology》2009,131(3-4):273-277

Human interferon-α (huIFN-α) is an important immunomodulatory substance used in the treatment and prevention of numerous infectious and immune-related diseases in animals. However, the immunostimulatory effects of huIFN-α in fish remain to be investigated. In the current study, the immune responses of the carp species Cyprinus carpio L. to treatment with huIFN-α were analyzed via measurement of superoxide anion production, phagocytic activity and the expression of cytokine genes including interleukin-1β, tumor necrosis factor-α and interleukin 10. Low doses of huIFN-α were administered orally once a day for 3 days, and sampling was carried out at 1, 3 and 5 days post-treatment. Our results indicate that a low dose of huIFN-α significantly increased phagocytic activity and superoxide anion production in the carp kidney. The huIFN-α-treated fish also displayed a significant upregulation in cytokine gene expression. The current study demonstrates the stimulatory effects of huIFN-α on the carp immune system and highlights the immunomodulatory role of huIFN-α in fish.  相似文献