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81.
Yuichi Iwasaki Takashi Kagaya Ken-ichi Miyamoto Hiroyuki Matsuda 《Water, air, and soil pollution》2012,223(1):145-158
We conducted a field survey in Japanese streams and rivers to generate useful information about whether the Japanese water
quality standard for zinc (Zn) in the freshwater environment (30 μg/L) is over- or underprotective of the populations and
communities of lotic benthic macroinvertebrates. Many macroinvertebrate populations were reduced and community characteristics
were altered at two polluted sites with Zn concentrations above 1,000 μg/L as compared with control sites with Zn concentrations
below 30 μg/L. In contrast, at least one site among three polluted sites with Zn concentrations of 80–126 μg/L experienced
noncritical effects (i.e., no significant difference was observed between the sample mean at a polluted site and that at the
control sites, and the sample mean was within the minimum–maximum range of those at the control sites) for most of the ten
community metrics for diversity and abundance. In addition, the abundances of 95% of the dominant taxa were not always significantly
lower at more than one polluted site (Zn concentrations, ≥80 μg/L). Our results suggest that Zn concentrations below approximately
100 μg/L are likely to protect most aspects of richness and abundance of the riverine macroinvertebrate communities in the
study areas. This study shows a case that the Japanese Zn standard is likely overprotective of the macroinvertebrate populations
and communities. 相似文献
82.
Kazutaka Kido Rie Adachi Masaru Hasegawa Kazutaka Yano Yasufumi Hikichi Shigeharu Takeuchi Tae Atsuchi Yuichi Takikawa 《Journal of General Plant Pathology》2008,74(4):302-312
An internal fruit rot with a malodor was found in netted melons (Cucumis melo L.) in commercial greenhouses in Kochi Prefecture, Japan, in 1998, despite their healthy appearance and lack of water-soaking
or brown spots on the surface. A yellow bacterium was consistently isolated from the affected fruits. To confirm the pathogenicity
of eight representative isolates of the yellow bacterium, we stub-inoculated ovaries (immature-fruits) 5–7 days after artificial
pollination, with a pin smeared with bacteria. After the melon fruits had grown for 60 more days, an internal fruit rot resembling
the natural infection appeared, and the inoculated bacterium was reisolated. The melon isolates had properties identical with
Pantoea ananatis, such as gram-negative staining, facultative anaerobic growth, indole production, phenylalanine deaminase absence, and acid
production from melibiose, sorbitol, glycerol, and inositol. Phylogenetic analysis based on 16S rDNA sequences showed that
the melon bacterium positioned closely with known P. ananatis strains. The melon bacterium had indole acetic acid (IAA) biosynthesis genes (iaaM and iaaH) and a cytokinin biosynthesis gene (etz). The bacterium could be distinguished from the other ‘Pantoea’ group strains by rep-PCR genomic fingerprinting. From these results, the causal agent of internal fruit rot was identified
as a strain of P.ananatis [Serrano in (Philipp J Sci 36:271–305, 1928); Mergaert et al. in (Int J Syst Bacteriol 43:162–173, 1993)].
The nucleotide sequence data reported are available in the DDBJ database under accessions AB297969, AB373739, AB373740, AB373741,
AB373742, AB373743 and AB373744. 相似文献
83.
Akira TAKEDA Hirofumi TSUKADA Yuichi TAKAKU Shun'ichi HISAMATSU 《Soil Science and Plant Nutrition》2009,55(3):349-357
To better understand the behavior of metals in soil–plant systems, their physicochemical forms in rhizosphere soil should be elucidated. The dissolved organic matter (DOM) in a soil solution influences the mobility and bioavailability of metals in soil. The present study examined the effects of plant growth on DOM–metal complexes in a rhizosphere soil solution using size exclusion chromatography combined with an inductively coupled plasma-mass spectrometer system (SEC–ICP-MS) and an ultrafiltration technique. Humus-rich volcanic ash soil from the surface of an agricultural field was used in a pot cultivation experiment. Brassica rapa nothovar. was cultivated in a pot in which rhizosphere soil (R) was separated by a nylon net screen from non-rhizosphere soil (NR). Soil solutions were collected using a high-speed centrifugation method 3 weeks after sowing and analyzed using SEC–ICP-MS. Some peaks of DOM with a high molecular size were detected in the ultraviolet-absorbing chromatograph (280 nm) of the soil solution samples. Their concentrations were much higher in the R solution than in the NR solution. Metals including Al, Fe, Cu, Zn, Pb, Y, La and U were detected at the ultraviolet peak positions of the DOM. The ultrafiltration experiment showed that the size distributions of the organic materials to which the metals were combined differed between the R and NR soil solutions. These results suggest that plant growth enhanced the dissolution of metals adsorbed with organic matter from the solid phase in rhizosphere soil. 相似文献
84.
Kirino Y Nakano N Hagio M Hidaka Y Nakamura-Uchiyama F Nawa Y Horii Y 《Veterinary parasitology》2008,158(4):376-379
A 5-year-old male mixed-bred boar-hunting dog with a Plott hound background weighing 23 kg was brought to the Veterinary Teaching Hospital, University of Miyazaki, in October 2002. The dog was diagnosed with active infection with the lung fluke Paragonimus westermani by serological testing and also by detection of parasite eggs in his feces. Subsequent examination of four other dogs working with this dog as a boar-hunting team revealed that all five dogs were infected with P. westermani. 相似文献
85.
Wei Wang Yuichi Hanai Chisato Takenaka Rie Tomioka Kazuya Iizuka Hajime Ozawa 《Journal of Forest Research》2016,21(5):251-258
Absorption of radiocesium (137Cs and 134Cs) through bark, and its subsequent translocation into wood and needles, has been suggested as a potential source of tree contamination, but the process is not well understood. Field experiments were conducted to confirm whether Cs could enter a Japanese cedar tree through the bark and how Cs moves within a tree. Stable Cs (133Cs) was applied to the bark at 1.2-m height on 10- and 26-year-old Japanese cedars. The 133Cs concentrations were determined in the bark, sapwood, and heartwood (for 26-year-old cedar only) of stem disks from several heights, as well as in current-year needles from the canopy. The 133Cs concentrations were considerably higher in the sapwood and heartwood of stem disks from 1.2-m height in treated trees than in untreated trees, suggesting that 133Cs penetrated the bark to enter the wood. The average 133Cs concentrations were higher in the heartwood than the sapwood, indicating 133Cs accumulation in the heartwood. High 133Cs concentrations in the needles of treated trees implied acropetal movement of 133Cs to actively growing organs. Our results demonstrate that Cs can enter Japanese cedar trees through the bark and that Cs is transported radially to the heartwood and vertically to the apex. 相似文献
86.
Fuminori Kobayashi Tsuyoshi Tanaka Hiroyuki Kanamori Jianzhong Wu Yuichi Katayose Hirokazu Handa 《Breeding Science》2016,66(2):213-225
A core collection of Japanese wheat varieties (JWC) consisting of 96 accessions was established based on their passport data and breeding pedigrees. To clarify the molecular basis of the JWC collection, genome-wide single-nucleotide polymorphism (SNP) genotyping was performed using the genotyping-by-sequencing (GBS) approach. Phylogenetic tree and population structure analyses using these SNP data revealed the genetic diversity and relationships among the JWC accessions, classifying them into four groups; “varieties in the Hokkaido area”, “modern varieties in the northeast part of Japan”, “modern varieties in the southwest part of Japan” and “classical varieties including landraces”. This clustering closely reflected the history of wheat breeding in Japan. Furthermore, to demonstrate the utility of the JWC collection, we performed a genome-wide association study (GWAS) for three traits, namely, “days to heading in autumn sowing”, “days to heading in spring sowing” and “culm length”. We found significantly associated SNP markers with each trait, and some of these were closely linked to known major genes for heading date or culm length on the genetic map. Our study indicates that this JWC collection is a useful set of germplasm for basic and applied research aimed at understanding and utilizing the genetic diversity among Japanese wheat varieties. 相似文献
87.
Yuichi Yamaoka Naoki Yamanaka Hajime Akamatsu Kazuhiro Suenaga 《Journal of General Plant Pathology》2014,80(2):184-188
Six races were identified among 26 single-lesion isolates of Phakopsora pachyrhizi from rust-infected leaves of nine samples of cultivated soybean and one sample of the wild host plant kudzu (Pueraria lobata) collected in Tsukuba and vicinity in Ibaraki, Central Honshu, Japan. Six races were detected on soybean cultivars and four races on kudzu. When two or more isolates obtained from the same samples were examined, the isolates were different races except from two samples. These results indicate that two or more races may be distributed on the same soybean cultivar and that the same races share soybean and kudzu hosts. 相似文献
88.
Kyoko Suzuki Tsutomu Suzuki Yukio Takahashi Mitsuhiro Okimoto Tetsuo Yamada Noriyasu Okazaki Yuichi Shimizu Masashi Fujiwara 《Journal of Wood Science》2009,55(1):60-68
The yields and properties of oil and gas fractions coproduced during carbonization of larch wood loaded with Ni 2%, Ni 2%+Ca
1%, and Ni 4% and without catalyst (None) at 700°–900°C were examined to clarify the catalytic effect in terms of conversion
into fluid fuels. The net calorific value of oil occurred mainly below 500°C and increased in the order None < Ni 2% < Ni
4% < Ni 2%+Ca 1%, while the yield decreased in this order. The same order held for the production of gases enriched with hydrogen
at 500°–700°C. Even above 800°C, markedly promoted evolution of hydrogen took place for all catalyst systems. These observations
confirmed the effectiveness of nickel-catalyzed carbonization at 900°C, particularly Ni 2%+Ca 1%, for both upgrading of oil
and gaseous fractions, although the quality of oil was not satisfactory. The catalysis of nickel with and without calcium
is discussed on the basis of the modified Broid-Shafizadeh scheme, and the scheme was altered to adapt to the high temperature
region where oil was no longer produced.
Part of this study was presented at the 14th Annual Meeting of the Japan Institute of Energy, Suita, August 2005, and at the
18th Symposium, Session D, of the Materials Research Society of Japan, Tokyo, December 2007 相似文献
89.
Yamada K Hirotsu T Matsuki M Butcher RA Tomioka M Ishihara T Clardy J Kunitomo H Iino Y 《Science (New York, N.Y.)》2010,329(5999):1647-1650
Population density-dependent dispersal is a well-characterized strategy of animal behavior in which dispersal rate increases when population density is higher. Caenorhabditis elegans shows positive chemotaxis to a set of odorants, but the chemotaxis switches from attraction to dispersal after prolonged exposure to the odorants. We show here that this plasticity of olfactory behavior is dependent on population density and that this regulation is mediated by pheromonal signaling. We show that a peptide, suppressor of NEP-2 (SNET-1), negatively regulates olfactory plasticity and that its expression is down-regulated by the pheromone. NEP-2, a homolog of the extracellular peptidase neprilysin, antagonizes SNET-1, and this function is essential for olfactory plasticity. These results suggest that population density information is transmitted through the external pheromone and endogenous peptide signaling to modulate chemotactic behavior. 相似文献