Habitat and prey selection of common minke,sei, and Bryde’s whales in mesoscale during summer in the subarctic and transition regions of the western North Pacific     

Hikaru Watanabe  Makoto Okazaki  Tsutomu Tamura  Kenji Konishi  Denzo Inagake  Takeharu Bando  Hiroshi Kiwada  Tomio Miyashita 《Fisheries Science》2012,78(3):557-567

This study represents the first quantitative analysis of the characteristics of the distribution areas and stomach contents of common minke whale Balaenoptera acutorostrata, sei whale B. borealis, and Bryde’s whale B. edeni in relation to oceanographic and prey environments in mid summer in the western North Pacific. Common minke whales were distributed within subarctic regions and the northernmost region of the transitional domain, coinciding with the main habitat of their preferred prey, Pacific saury Cololabis saira. Sei whales were mainly found in the northernmost part of the transition zone and showed prey preference for Japanese anchovy Engraulis japonica, which was significantly more abundant in the main distribution area of the whale than in its adjacent areas. “Hot spots” of Bryde’s whales were found in several regions of the transition zone between the subarctic boundary and the Kuroshio front. This whale species preferred Japanese anchovy as prey, for which the distribution density was significantly higher in the main distribution area of the whale than in the adjacent areas. These results indicate that the summer distributions of Pacific saury and Japanese anchovy greatly influence the distributions of these whale species, suggesting that the whales’ habitat selection is closely related to their prey selection.  相似文献   

Seed formation in triploid loquat (Eriobotrya japonica) through cross-hybridization with pollen of diploid cultivars     

Shinji Kikuchi  Miwako Iwasuna  Aya Kobori  Yasunori Tsutaki  Akihiro Yoshida  Yuri Murota  Eisho Nishino  Hidenori Sassa  Takato Koba 《Breeding Science》2014,64(2):176-182

As the fruits of loquat (Eriobotrya japonica, 2n = 2x = 34) carry large seeds, the breeding of seedless loquat has long been a goal. The recent creation of triploid cultivars (2n = 3x = 51) and the application of gibberellins allow commercial production of seedless loquat, but the possibility of seed formation in triploid loquats has not been carefully investigated. Through crossing experiments and cytological observations of meiosis and pollen tube growth, we found that the triploid line 3N-N28 was essentially self-sterile, but developed seeds on pollination with pollen from diploid cultivars at rates of up to 5.5%. Almost half of the seedlings survived to 5 months, and carried diploid (2n = 34), tetraploid (2n = 68), or aneuploid chromosome numbers. Our results suggest that triploid loquat cultivars might retain the risk of seed formation. Protection from pollination by diploid cultivars or the development of new triploid cultivars will be necessary to ensure the production of seedless loquat fruits.  相似文献   

Studies on cytopathogenic viruses isolated from cats with respiratory infections. I   总被引：1，自引：0，他引：1  

M Kamizono  S Konishi  M Ogata  S Kobori 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1968,30(4):197-206

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Seasonal changes of azimuthal,radial, and tree-to-tree variations in sap flux affect stand transpiration estimates in a <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> forest,central Taiwan     

Chen-Wei Chiu  Tomonori Kume  Hikaru Komatsu  Han Tseng  Tsong-Huei Wey  Kyoichi Otsuki 《Journal of Forest Research》2016,21(4):151-160

Stand transpiration (E) estimated using the sap flux methods is affected by the azimuthal, radial, and tree-to-tree variations of sap flux. Although several studies have examined the relative importance of the three variations in estimating E, the seasonality of the three variations remains unknown. In the current study, we attempted to clarify whether the relative importance of these three variations could show seasonal changes. Using sap flux data measured in a subtropical cloud forest from August 2010 to July 2011, we calculated the differences resulting from omitting the three variations in estimating E. The effects of the three variations in estimating E showed seasonality. The azimuthal and tree-to-tree variations were more pronounced during winter, whereas the radial variation was more pronounced during summer. However, the effect of tree-to-tree variation was consistently much larger than the other two variations throughout the study period. The tree-to-tree variation is more important in estimating E monthly, seasonally and annually than both the azimuthal and radial variations, although all three variations have shown seasonality. In addition, the sensor allocation for summer would be acceptable for the practical estimation of E if aiming at the long time scale.  相似文献   

Effects of wet–dry cycling on the mechanical properties of Arundo donax L. used for the vibrating reed in woodwind instruments     

Akahoshi  Hikaru  Obataya  Eiichi 《Wood Science and Technology》2015,49(6):1171-1183

Wood Science and Technology - The effects of wet–dry and moist–dry cycling on the mechanical properties of reed (Arundo donax L.) were investigated. Because water-soluble extractives...  相似文献   

Kid depletion in mouse oocytes associated with multinucleated blastomere formation and inferior embryo development          下载免费PDF全文

Akiyoshi Egashira  Nobuhiko Yamauchi  Md. Rashedul Islam  Kazuki Yamagami  Asami Tanaka  Hikaru Suyama  El‐Sharawy Mohamed El‐Sayed  Shoji Tabata  Takashi Kuramoto 《Animal Science Journal》2016,87(8):1048-1054

This study investigated the knockdown (KD) of Kid on maturation developmental competence and multinucleation of mouse germinal vesicle (GV) oocytes after parthenogenetic activation. Data revealed that Kid messenger RNA (mRNA) was expressed in GV and MII stage oocyte and 1‐ and 2‐cell embryos. Additionally, Kid mRNA expression in the Kid KD group decreased by nearly 46% compared to the control small interfering RNA (siRNA) groups. The rate of multinucleated embryos in the Kid KD group (52.4%) was significantly higher (P < 0.05) than the control siRNA group (4.7%). Finally, the developmental rates were significantly lower in the Kid siRNA group at > 4‐cell stage (28.6% vs. 53.5%) and the blastocyst stage (2.4% vs. 23.3%) compared to the control siRNA groups. Suppression of Kid using siRNA caused multinucleation in early embryos with high frequency and it may increase 2‐ to 4‐cell arrested embryos and reduce the developmental competence to blastocyst.  相似文献   

Effect of interleukin‐1β on occludin mRNA expression in the duodenal and colonic mucosa of dogs with inflammatory bowel disease          下载免费PDF全文

Misato Ogawa  Hironari Osada  Ayana Hasegawa  Hikaru Ohno  Nanako Yanuma  Kazuaki Sasaki  Minoru Shimoda  Junsuke Shirai  Hirotaka Kondo  Keitaro Ohmori 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2018,32(3):1019-1025

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Rainfall interception in a moso bamboo (Phyllostachys pubescens) forest   总被引：1，自引：0，他引：1  

Yuka Onozawa  Masaaki Chiwa  Hikaru Komatsu  Kyoichi Otsuki 《Journal of Forest Research》2009,14(2):111-116

In recent years, moso bamboo (Phyllostachys pubescens) forest areas in Japan have rapidly expanded, and bamboo is now invading nearby natural or plantation forests. To date, only one study has examined the rainfall interception of a moso bamboo forest. In that study, it was reported that the interception ratio (interception/rainfall) of the bamboo forest did not exceed the interception ratios of other natural and plantation forests (n = 4) in Japan. To expand the current state of knowledge about rainfall interception of bamboo forests, we measured throughfall and stemflow at another bamboo forest site. Annual rainfall (Rf), throughfall (Tf), and stemflow (Sf) during the measurement period were 2,105, 1,556, and 322 mm, respectively. Annual rainfall interception at the plot (I) was 228 mm. Tf/Rf, Sf/Rf, and I/Rf were 73.9, 15.3, 10.8%, respectively. I/Rf was less than 20% throughout the year except in October, the month with lowest rainfall. We also summarized rainfall interception data from 19 other natural and plantation forests. The I/Rf value of our site did not exceed the I/Rf values of these natural and plantation forests (n = 19). Our data will be useful for assessing changes in water resources that result from replacement of natural or plantation forests by bamboo forests.  相似文献   

SSR-tagged breeding scheme for allogamous crops: a trial in bunching onion (<Emphasis Type="Italic">Allium fistulosum</Emphasis>)     

Hikaru Tsukazaki  Ken-Ichiro Yamashita  Akio Kojima  Tadayuki Wako 《Euphytica》2009,169(3):327-334

In several autogamous and vegetatively propagated crops, DNA markers have been used for cultivar identification. However, allogamous crops such as bunching onion (Allium fistulosum L.) are recalcitrant to marker-aided cultivar identification, as well as hybrid seed purity tests, due to the high degree of genetic heterogeneity within each cultivar. To aid cultivar identification and ensure its accuracy in bunching onion, we proposed the “SSR-tagged breeding” scheme in our previous study. The feasibility of this scheme was investigated here using a landrace of bunching onion with two populations tagged with two or four selected SSR markers. Compared with a control population, no significant differences were detected in the agronomic traits of the SSR-tagged populations. The targeted SSR loci were genetically uniform within each population whereas other loci maintained high heterogeneity. These results demonstrate that the SSR-tagged breeding scheme, even with a very small number of markers, is efficient for the identification of newly bred cultivars, and consequently for F₁ purity tests, in allogamous crops in which inbreeding depression is as severe as in bunching onion.  相似文献   

Genetic identification and morphology of naturally spawned eggs of the Japanese eel Anguilla japonica collected in the western North Pacific     

Tatsuki Yoshinaga  Michael J. Miller  Kazuki Yokouchi  Tsuguo Otake  Shingo Kimura  Jun Aoyama  Shun Watanabe  Akira Shinoda  Machiko Oya  Sachie Miyazaki  Kei Zenimoto  Ryusuke Sudo  Tetsuya Takahashi  Hyojin Ahn  Ryotaro Manabe  Seishi Hagihara  Hiroshi Morioka  Hikaru Itakura  Masamichi Machida  Kazuyuki Ban  Mayu Shiozaki  Bunpei Ai  Katsumi Tsukamoto 《Fisheries Science》2011,77(6):983-992

Eggs of the Japanese eel Anguilla japonica collected in the western North Pacific were identified by onboard species-specific polymerase chain reaction (PCR) and DNA nucleotide sequencing after the cruise. Fish eggs of various species were collected by large plankton net tows at 12 stations along the southern part of the West Mariana Ridge on 19–25 May 2009. A total of 43 fish eggs were distinguished morphologically as possibly being of A. japonica. Thirty-one of those were analyzed by PCR, which included 15 eggs collected at 12°50–55′N, 141°15–20′E (in 5 tows) that showed positive results. The 16S ribosomal RNA (rRNA) gene sequences of eggs determined after the cruise indicated that 31 A. japonica eggs had been collected. The remaining eggs were of mesopelagic eel species (Serrivomeridae and Derichthyidae), or unidentified species. The morphological characteristics of the A. japonica eggs were consistent with those of artificially spawned eggs, except they had a slightly larger diameter. The egg diameter range did not overlap with those of mesopelagic eels of the Serrivomeridae, which often spawn in the same area as A. japonica. These results suggest that egg diameter and embryo shape can be used to morphologically identify naturally spawned A. japonica eggs.  相似文献