Bioremediation of organically enriched sediment deposited below fish farms with artificially mass-cultured colonies of a deposit-feeding polychaete <Emphasis Type="Italic">Capitella</Emphasis> sp. I     

Kyoko Kinoshita  Sayaka Tamaki  Miho Yoshioka  Sarawut Srithonguthai  Tadao Kunihiro  Daigo hama  Kouichi Ohwada  Hiroaki Tsutsumi 《Fisheries Science》2008,74(1):77-87

ABSTRACT:   For bioremediation of organically enriched sediment deposited below fish farms, the extremely high potential for population growth of a deposit-feeding polychaete, Capitella sp. I, in the organically enriched sediment, and the effect on decomposition of organic matter in the sediment, were examined. A mass-culturing technique was conducted for this species. Bioremediation experiments were conducted on the organically enriched sediment in a fish farm in Kusuura Bay, Japan in 2003–2006. Approximately 1.7 million individuals of the worms were placed on the sediment below one net pen in December 2003, 9.3 million individuals in November 2004, and 2.2 million individuals in November 2005. After the worms were spread on the sediment, they rapidly increased in number and reached the highest densities of approximately 134 000 inds/m² in February 2004, 527 000 inds/m² in March 2005 and 103 000 inds/m² in January 2006. In the process of rapid population growth, the decomposition of the organic matter of the sediment was enhanced markedly. Our results demonstrate that the promotion of population growth by spreading cultured colonies of Capitella can enhance the decomposition rate of organic matter markedly in organically enriched sediment below fish farms. This method is promising for minimization of the negative effects of fish farms.  相似文献   

Production of asexual and sexual offspring in the triploid sexual planarian Dugesia ryukyuensis     

Kazuya KOBAYASHI  Sachiko ARIOKA  Motonori HOSHI  Midori MATSUMOTO 《Integrative zoology》2009,4(3):265-271

Certain freshwater planarians reproduce asexually as well as sexually, and their chromosomal ploidies include polyploidy, aneuploidy and mixoploidy. Previously, we successfully performed an experiment in which a clonal population produced by asexual reproduction of the Dugesia ryukyuensis (OH strain) switched to the sexual mode of reproduction. Worms of this strain are triploid with a pericentric inversion on Chromosome 4. The worms were switched to sexual reproduction after being fed with sexually mature Bdellocephala brunnea, which is a sexually reproducing species. The resulting sexualized OH strain produced cocoons filled with several eggs. Two putative factors, Mendelian factor(s) and chromosomal control(s), have been proposed as determining the reproductive mode. The present study demonstrated that inbreeding of the resultant sexualized worms produced the following four types of offspring through sexual reproduction: diploid asexual worms, triploid asexual worms, diploid sexual worms and triploid sexual worms. The chromosomal mutation on Chromosome 4 was inherited by these offspring independent of their reproductive mode. These results provide two important pieces of information: (i) the putative genetic factor was not necessarily inherited in a Mendelian fashion; and (ii) the reproductive mode is not regulated by chromosomal changes such as polyploidy or chromosomal mutations. This suggests that asexuality in D. ryukyuensis is regulated by an unknown factor(s) other than a Mendelian factor or a chromosomal control.  相似文献   

Production of carbohydrates, lignins, and minor components from triticale straw by hydrothermal treatment     

Pronyk C  Mazza G  Tamaki Y 《Journal of agricultural and food chemistry》2011,59(8):3788-3796

The effects of temperature (116 °C, 150 °C, and 183 °C) and flow rate (66, 150, and 234 mL/min) on the fractionation of triticale straw into different products was determined using a flow-through pressurized low polarity water reactor. The greatest concentration of biomass was hydrolyzed and extracted in the first two of eight 600 mL fractions (1.2 L), after which dry matter yield decreased. Carbohydrate, lignin, acetyl group, and uronic acid yield increased with temperature, but there was no effect due to flow rate. Most dry matter extracted at 116 °C was probably associated with the extractives. Xylan yields decrease slightly at the highest flow rate due to a decrease in the residence time of the acids produced in situ. Carbohydrates were extracted mostly as oligosaccharides, and the highest processing temperature resulted in the production of furans from the xylose and arabinose in the liquid extracts.  相似文献   

Age,growth and maturation of the blackspot snapper <Emphasis Type="Italic">Lutjanus fulviflammus</Emphasis> around Okinawa Island,Japan     

Tamaki?Shimose  Katsunori?TachiharaEmail author 《Fisheries Science》2005,71(1):48-55

ABSTRACT:   The blackspot snapper Lutjanus fulviflammus is one of the most common Lutjanus species landed and consumed on Okinawa Island, Japan. Using 901 fish (29.9–304.2 mm in standard length; SL) obtained from fish markets or caught by angling, the age, growth, maturation size and maturation age were estimated. Each opaque zone formed on the otolith every year correlated with their spawning and was thought to be an annual ring. The main spawning season was estimated to be from April to July, which peaked in May and June, with a few mature fish collected in August and September. Maximum ages were observed as 24 years for both sexes and L_∞ (mm SL), K and t₀ (years) of the von Bertalanffy growth formula were estimated to be 276, 0.144 and −5.22 for females and 247, 0.227 and −3.18 for males, respectively. First maturation size and age were estimated to be 175 mm SL and 2 years for both sexes. A faster growth rate up to 2 years will allow reproduction at a young age and provide many chances for spawning throughout their long life. Furthermore, the possibility exists that populations would easily recover if regulations were established.  相似文献   

Nocturnal isoprene emission from mature trees and diurnal acceleration of isoprene oxidation rates near Quercus serrata Thunb. leaves     

Takafumi Miyama  Motonori Okumura  Yuji Kominami  Kennichi Yoshimura  Mioko Ataka  Akira Tani 《Journal of Forest Research》2013,18(1):4-12

Quercus serrata Thunb. ex Murray is a widespread deciduous oak in China, the Korean Peninsula, and Japan, and a strong isoprene emitter. Establishing accurate inventories of this species and estimating net carbon budgets, including biogenic volatile organic compounds (BVOC), necessitates detailed evaluation of BVOC emission and oxidation characteristics. Emissions of isoprene, the most abundant BVOC, presumably contribute to atmospheric chemistry through the formation of photochemical oxidants and secondary organic aerosols. We built an isoprene flux monitoring system to simultaneously reveal characteristics of the flux and fate of isoprene at multiple locations in Q. serrata forests. We used proton transfer reaction mass spectrometry (PTR-MS) and an automated closed chamber to measure isoprene emissions from soil and leaves in a warm-temperate Q. serrata forest. We used a relaxed eddy accumulation system with PTR-MS to simultaneously measure the canopy flux. In continuous foliage chamber measurements, we observed daily variations of isoprene emissions and continuous nocturnal emissions from leaves. Nocturnal emissions exceeded 25 % of total daily leaf emissions and were relatively high at sunset and low at sunrise. These results suggest that nocturnal emissions from mature trees may not be negligible. When leaf emissions were high in the daytime, the canopy isoprene flux tended to plateau at an upper limit. Observations of isoprene concentrations and gradients suggest that the plateau was caused by acceleration of isoprene oxidation, and sequential formation of secondary organic aerosols may occur near the leaf just after emission. Elucidation of these linkages may require continuous field measurements with a simultaneous multi-flux monitoring system.  相似文献   

Differential expression of heat-shock proteins in F2 offspring from F1 hybrids produced between thermally selected and normal rainbow trout strains     

Nobuhiko Ojima  Miyuki Mekuchi  Toshinao Ineno  Koichi Tamaki  Akio Kera  Shigeharu Kinoshita  Shuichi Asakawa  Shugo Watabe 《Fisheries Science》2012,78(5):1051-1057

Rainbow trout Oncorhynchus mykiss is a cold-water aquaculture species, and a thermally selected strain has been developed by multigenerational high-temperature breeding in Japan. We examined the expression of heat-shock proteins as candidates responsible for thermotolerance in rainbow trout using F2 offspring from F1 hybrids produced between thermally selected and normal strains. From F2 offspring, two groups were selected for western blot analysis, namely, low- and high-thermotolerance groups (times to loss of equilibrium were <30 and ??60?min, respectively). We demonstrated that the expression levels of Hsp70, Hsp60, and Hsp40 in tail fin tissues were significantly higher in the individuals with high thermotolerance than in those with low thermotolerance under non-heat-shock conditions. In particular, Hsp70 was expressed only in the individuals with high thermotolerance. These results suggest that Hsp70 is a major protein responsible for conferring thermotolerance in rainbow trout.  相似文献   

Identification of Antiviral Agents Targeting Hepatitis B Virus Promoter from Extracts of Indonesian Marine Organisms by a Novel Cell-Based Screening Assay     

Atsuya Yamashita  Yuusuke Fujimoto  Mayumi Tamaki  Andi Setiawan  Tomohisa Tanaka  Kaori Okuyama-Dobashi  Hirotake Kasai  Koichi Watashi  Takaji Wakita  Masaaki Toyama  Masanori Baba  Nicole J. de Voogd  Shinya Maekawa  Nobuyuki Enomoto  Junichi Tanaka  Kohji Moriishi 《Marine drugs》2015,13(11):6759-6773

The current treatments of chronic hepatitis B (CHB) face a limited choice of vaccine, antibody and antiviral agents. The development of additional antiviral agents is still needed for improvement of CHB therapy. In this study, we established a screening system in order to identify compounds inhibiting the core promoter activity of hepatitis B virus (HBV). We prepared 80 extracts of marine organisms from the coral reefs of Indonesia and screened them by using this system. Eventually, two extracts showed high inhibitory activity (>95%) and low cytotoxicity (66% to 77%). Solvent fractionation, column chromatography and NMR analysis revealed that 3,5-dibromo-2-(2,4-dibromophenoxy)-phenol (compound 1) and 3,4,5-tribromo-2-(2,4-dibromophenoxy)-phenol (compound 2), which are classified as polybrominated diphenyl ethers (PBDEs), were identified as anti-HBV agents in the extracts. Compounds 1 and 2 inhibited HBV core promoter activity as well as HBV production from HepG2.2.15.7 cells in a dose-dependent manner. The EC₅₀ values of compounds 1 and 2 were 0.23 and 0.80 µM, respectively, while selectivity indexes of compound 1 and 2 were 18.2 and 12.8, respectively. These results suggest that our cell-based HBV core promoter assay system is useful to determine anti-HBV compounds, and that two PBDE compounds are expected to be candidates of lead compounds for the development of anti-HBV drugs.  相似文献   

Genetic variation and population demography of the landrace population of Camellia sinensis in Kasuga,Gifu Prefecture,Japan     

Ichiro Tamaki  Tatsunori Kuze  Keiko Hirota  Mizuo Mizuno 《Genetic Resources and Crop Evolution》2016,63(5):823-831

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Solar and lunar influences on the spawning activity of Pacific bluefin tuna (Thunnus orientalis) in the south‐western North Pacific spawning ground          下载免费PDF全文

Tamaki Shimose  Yoshimasa Aonuma  Toshiyuki Tanabe  Nobuaki Suzuki  Minoru Kanaiwa 《Fisheries Oceanography》2018,27(1):76-84

Pacific bluefin tuna (Thunnus orientalis) migrate to the south‐western North Pacific spawning grounds (area off Taiwan and the Ryukyu Islands) from mid‐April to early July. Reproductive traits of the species in this area have been studied for some time; however, temporal changes in spawning activity during this season are not well understood. In this study, the spawning fraction (proportion of females with post‐ovulatory follicles to total mature females) in relation to solar calendar date and lunar day was investigated using a generalized linear model. Sampling was conducted almost every day throughout the fishing season at Ishigaki Fishing Port (24°21′N, 124°09′E), southern Japan between 2012 and 2014, and a total of 212 ovaries were histologically observed. Spawning fraction continued to increase from the beginning to the end of the season. This indicates that the peak season of occurrence in the area and the peak of spawning activity did not co‐occur. Spawning fraction also changed with the lunar day and significantly increased around the new moon. Eggs and early larvae hatched around the new moon may have reduced the predation risk during night‐time. These findings improve the current knowledge of reproductive biology and resource evaluation of Pacific bluefin tuna and indicate that spawning activity is not constant, and has two or three peaks in each season.  相似文献   

Detection of Babesia microti-like parasite in filter paper-absorbed blood of wild rodents     

Okabayashi T  Hagiya J  Tsuji M  Ishihara C  Satoh H  Morita C 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(2):145-147

The first case of human babesiosis was reported in Japan. The epidemiology of this disease in Japanese nature remains unclear. In this study, 97 common field mice captured in Hokkaido, Japan, were examined. Blood specimens absorbed onto filter papers were eluted and tested by nested PCR using specific primers for the B. microti nuclear small subunit rRNA genome. Twenty-three percent (11/47) of Apodemus speciosus and four percent (2/50) of Clethrionomys rufocanus were positive. The 159-bp primary sequences of PCR products tested exhibited 97.5% and 96.8% homology with those of the human isolate in Japan and of U.S. strains of B. microti, respectively.  相似文献