Long‐term changes in recruitment of age‐0 Pacific bluefin tuna (Thunnus orientalis) and environmental conditions around Japan          下载免费PDF全文

Yukimasa Ishida  Hiromu Fukuda  Ko Fujioka  Osamu Sakai  Yuko Hiraoka  Kazuhiro Oshima  Shuya Nakatsuka  Nobuaki Suzuki  Hiroyuki Shimada 《Fisheries Oceanography》2018,27(1):41-48

Recruitment of age‐0 Pacific bluefin tuna (Thunnus orientalis) from 1952 to 2014 was examined by a sequential regime shift detection method. The regime shifts in recruitment were detected in 1957, 1972, 1980, 1994 and 2009. The durations of regime shift ranged from 8–15 years and averaged 13.0 years. In both the total (1952–2014) and data rich (1980–2014) periods, negative relationships were found between recruitment and the Pacific Decadal Oscillation in autumn, and positive relationships were found between recruitment and sea surface temperature (SST) anomalies in the northern part of the East China Sea, in the southwestern part of the Sea of Japan, and in the waters off Shikoku and Tokai in summer and autumn. The 1994 and 2009 regime shifts in recruitment occurred in the same years as shifts in SST anomalies in the northern part of the East China Sea in summer. These results suggest that the ocean conditions in the northern part of the East China Sea are closely related to recruitment of Pacific bluefin tuna, and that the warmer conditions result in higher recruitment of the species.  相似文献   

Species and lineage identification for yellowfin <Emphasis Type="Italic">Thunnus albacares</Emphasis> and bigeye <Emphasis Type="Italic">T. obesus</Emphasis> tunas using two independent multiplex PCR assays     

Ryouichi Higashi  Kay Sakuma  Satoru N. Chiba  Nobuaki Suzuki  Seinen Chow  Yasuko Semba  Hiroaki Okamoto  Kenji Nohara 《Fisheries Science》2016,82(6):897-904

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Root and crown rot of strawberry caused by Pythium helicoides and its distribution in strawberry production areas of Japan     

Yasushi Ishiguro  Kayoko Otsubo  Hideki Watanabe  Mikihiko Suzuki  Kiichi Nakayama  Takashi Fukuda  Masashi Fujinaga  Haruhisa Suga  Koji Kageyama 《Journal of General Plant Pathology》2014,80(5):423-429

Pythium species were isolated from seedlings of strawberry with root and crown rot. The isolates were identified as P. helicoides on the basis of morphological characteristics and sequences of the ribosomal DNA internal transcribed spacer regions. In pathogenicity tests, the isolates caused root and crown rot similar to the original disease symptoms. Multiplex PCR was used to survey pathogen occurrence in strawberry production areas of Japan. Pythium helicoides was detected in 11 of 82 fields. The pathogen is distributed over six prefectures.  相似文献   

Mercury distribution in tephra soil layers in Hokkaido, Japan, with reference to 34,000-year stratification     

Satoru HOBARA  Naoharu MIZUNO  Yoji AMANO  Hiroshi YOKOTA  Hiroyuki TANIYAMA 《Soil Science and Plant Nutrition》2009,55(4):582-589

Tephra from volcanic eruptions contains only small amounts of mercury (Hg) right after the eruption because the high temperature at eruption evaporates Hg in volcanic ash. Thus, accumulation of Hg in tephra soil layers during the dormant periods of the volcano may reflect Hg deposition while the layer was exposed to the atmosphere. To estimate sequential changes in Hg deposition, we measured the Hg content and accumulation in tephra layers from 6 sites in Hokkaido known to have many tephra layers derived from volcanic eruptions over a 34,000-year period. Mercury content and accumulation rate in the soil profiles varied widely depending on the tephra. In each tephra layer, the Hg content and accumulation rates increased principally at the upper soil horizons and decreased at the lower depths. The Hg deposition rates calculated from the amount of Hg accumulated in the tephra layers were similar within the same tephra. These characteristics of Hg distribution indicate that Hg deposition accumulated on the surface of each tephra layer during the period the tephra layer was exposed to the atmosphere. Although physicochemical processes such as leaching out, wind erosion, and volatilization might lead to over- and/or underestimation of the deposition rates, our estimated amounts of Hg were markedly higher in the tephra soils after 1,600 year BP than before that time. The results of this study suggest that tephra layers in Hokkaido offer important implications for understanding of the historical changes in atmospheric Hg deposition.  相似文献   

A new method for evaluating symplastic cadmium absorption in the roots of Solanum melongena using enriched isotopes ¹¹³Cd and ¹¹⁴Cd     

Shinsuke MORI  Akira KAWASAKI  Satoru ISHIKAWA  Tomohito ARAO 《Soil Science and Plant Nutrition》2009,55(2):294-299

Radioisotope techniques are well known as methods for evaluating symplastic ion absorption in roots. In the present study, a new method for evaluating symplastic cadmium (Cd) absorption in plant roots was developed using the enriched isotopes ¹¹³Cd and ¹¹⁴Cd. Seedlings of Solanum melongena were exposed to an enriched isotope solution of ¹¹³Cd at 25°C for 30 min. The roots were excised from each seedling and were then immersed in a cold buffer solution without Cd at 2°C for 120 min to suppress the metabolic activity of the roots. Finally, the roots were treated with a cold buffer solution containing enriched stable isotope ¹¹⁴Cd at 2°C for 120 min, whereby the apoplastically bound ¹¹³Cd was desorbed. We tested the validity of our method for evaluating symplastic Cd in roots compared with the conventional method based on differences in the amount of Cd absorbed at 2°C and 25°C using unlabeled Cd. There was no difference in the symplastic Cd content of the roots between the two methods. These results indicate that it is possible to evaluate the symplastic Cd content in roots using the enriched isotopes ¹¹³Cd and ¹¹⁴Cd.  相似文献   

Greater contribution of low-nutrient tolerance to sorghum and maize growth under combined stress conditions with high aluminum and low nutrients in solution culture simulating the nutrient status of tropical acid soils     

Afrin AKHTER  Md. Shahadat Hossain KHAN  Egashira HIROAKI  Keitarou TAWARAYA  Idupulapati M. RAO  Peter WENZL  Satoru ISHIKAWA  Tadao WAGATSUMA 《Soil Science and Plant Nutrition》2009,55(3):394-406

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Identification of a resistant protein from scallop shell extract and its bile acid-binding activity     

Manabu Fukuda  Kohji Takahashi  Chiharu Ohkawa  Yuya Sasaki  Yasushi Hasegawa 《Fisheries Science》2013,79(6):1017-1025

In this study, we showed that feeding rats the organic extract of scallop shells (scallop shell extract) caused a decrease in the weights of white adipose tissues in rats fed a high-fat diet. In addition, the cholesterol concentration in the serum of rats that received a diet containing scallop shell extract was significantly lower than that in the serum of rats on the control diet. Feeding this scallop shell extract to rats increased the fecal weight as well as the fecal excretion of bile acids. The amino acid composition of the feces from rats fed the scallop shell extract was different from that of feces from rats fed the control diet, and treatment of the extract with pepsin and pancreatin identified a protein with a molecular weight of 90 kDa (90-kDa protein) as one of the indigestible proteins. Interestingly the 90-kDa protein was found to be identical to a free radical-scavenging protein we previously identified and showed the ability to bind bile acids. These results suggest that indigestible proteins (resistant proteins) in the scallop shell extract, including the 90-kDa protein, inhibit the absorption of bile acid by binding to it and cause increased excretion of fecal bile acid, which subsequently may decrease the serum cholesterol level.  相似文献   

Free radical scavenging ability and structure of a 90-kDa protein from the scallop shell     

Takuya Mitsuhashi  Kohji Ono  Manabu Fukuda  Yasushi Hasegawa 《Fisheries Science》2013,79(3):495-502

We have previously reported that the scallop shell extract possesses free radical scavenging activity. In this study, we isolated a glycoprotein with a molecular weight of approximately 90 kDa (named 90-kDa protein) which showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion radical scavenging, reducing, and ferrous ion-chelating activities. Amino acid composition analysis showed that the 90-kDa protein was rich in Asx (Asp or Asn), Ser and Gly residues. A BLAST search of partial amino acid sequences determined by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry revealed that the 90-kDa protein is a novel protein. The 90-kDa protein is a yellow protein that contains fluorescent substances. To the best of our knowledge, this is the first report of a radical scavenging protein from the scallop shell.  相似文献   

Modelling the distribution of the pan‐continental invasive fish Pseudorasbora parva based on landscape features in the northern Kyushu Island,Japan     

Shinji Fukuda  Bernard De Baets  Norio Onikura  Jun Nakajima  Takahiko Mukai  ANS M. Mouton 《水产资源保护:海洋与淡水生态系统》2013,23(6):901-910

A phylogeographic study of the Japanese earthworm,Metaphire sieboldi (Horst, 1883) (Oligochaeta: Megascolecidae): Inferences from mitochondrial DNA sequences     

Yukio Minamiya  Jun Yokoyama  Tatsuya Fukuda 《European Journal of Soil Biology》2009,45(5-6):423-430

To clarify the historical phylogeography of a Japanese earthworm, nucleotide sequence variations of Metaphaire sieboldi were investigated with respect to its geographic distribution. Sequencing of mitochondrial DNA (mtDNA), including the cytochrome oxidase subunit I (COI) region and the 16S rDNA region, of 72 samples including 4 outgroup taxa, and phylogenetic analyses using neighbour-joining (NJ) and Bayesian inference (BI) methods indicated that M. sieboldi forms a monophyletic group. This monophyletic group was divided into seven subgroups; most subgroups comprised individuals from several areas, except for southern Shikoku and southern Kyushu. The phylogenetic tree demonstrated that the Shikoku and Kinki populations were paraphyletic at the basal node, and individuals from Kyushu and western Shikoku were positioned at the advanced group. Estimated phylogeographic events based on mtDNA analyses include (1) M. sieboldi originated in Shikoku and/or Kinki, (2) individuals from Chugoku and Kyushu have a common ancestor from Shikoku, and (3) individuals from western Shikoku originated from Kyushu progenitors (about 0.4–0.5 mya) after separation by rising sea levels.  相似文献