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21.
Takashi Naito Minoru Tanaka Satoshi Taba Tesuya Toyosato Atsushi Oshiro Kazuko Takaesu Kazuo Hokama Tomio Usugi Shinji Kawano 《Journal of General Plant Pathology》2007,73(2):139-141
In 1999, a disease of chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitamura], characterized by virescence of flowers, occurred in Okinawa Prefecture. The causal agent was identified
as “Candidatus Phytoplasma aurantifolia” based on 16S rDNA sequencing.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB247462. 相似文献
22.
Taketo Ashizawa Masashi Sasahara Atsushi Ohba Takeshi Hori Kouji Ishikawa Yukio Sasaki Tomohisa Kuroda Ryoei Harasawa Kaoru Zenbayashi-Sawata Shinzo Koizumi 《Journal of General Plant Pathology》2007,73(1):15-21
Leaf blast suppression in multilines was evaluated based on the number of susceptible lesions observed in a pure stand of
susceptible rice cultivar Sasanishiki, and in 1 : 1 and 1 : 3 mixtures of Sasanishiki and a resistant near-isogenic line,
Sasanishiki BL4 or BL7, from 1998 to 2001. The number of lesions first observed in fields in the 1 : 1 and 1 : 3 mixtures
were close to theoretical numbers calculated using the number of lesions observed in the pure stands and the ratios of the
susceptible Sasanishiki in the mixtures. The ratio of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number
in the pure stand was 0.29 and 0.09, respectively. The relationship between these ratios and the ratios of susceptible Sasanishiki
in mixtures was defined in an equation to estimate the degree of leaf blast suppression. Validation studies for the ratios
of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand were conducted in two different locations
and showed that the ratios are almost acceptable. The calculated autoinfection to alloinfection ratio was 1.3 and 1.4 in the
1 : 1 and 1 : 3 mixtures, respectively, suggesting that the calculated ratio will affect the degree of leaf blast suppression.
Thus, predictors were obtained to estimate leaf blast suppression for effective blast control in multilines. 相似文献
23.
In the tropical canopy tree, Dryobalanops aromatica Gaertn. f., upper-canopy leaves (UL) develop under sunlit conditions but are subjected to self-shading within the crown as they age. In contrast, lower-canopy leaves (LL) are exposed to uniform dim light conditions throughout their life span. By comparing leaf morphology and physiology of UL and LL, variations in leaf characteristics were related to leaf age and self-shading. Mass-based chlorophyll (chl) concentration and the chlorophyll/nitrogen (chl/N) ratio were lower and the chl a/b ratio was higher in UL than in LL. In UL, the chl/N ratio gradually increased and the chl a/b ratio gradually decreased with leaf aging, whereas these ratios remained unchanged with leaf age in LL. The effective quantum yield of photosystem II (PSII) (DeltaF/F(m)') at a given irradiance remained unchanged with leaf age in LL, whereas DeltaF/F(m)' changed with leaf age in UL. These data indicate N reallocation within the leaves from carbon fixation components to light harvesting components and a dynamic regulation of photochemical processes of PSII in response to increased self-shading of UL. Despite the difference in light environment with leaf age between UL and LL, maximum photosynthetic rates and nitrogen-use efficiency decreased with leaf aging in both UL and LL. Constancy in the chl/N ratio with leaf age in LL indicated that the decrease in photosynthetic capacity was caused by effects other than shading, such as leaf aging. We conclude that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative. 相似文献
24.
Atsushi Yoshimoto 《Journal of Forest Research》2001,6(1):21-30
The objective of this paper is to investigate potential use of a spatially constrained harvest scheduling model for biodiversity
concerns. Change in the degree of biodiversity is represented only by spatial characteristics of harvesting patterns of forest
stands with different exclusion periods applied to adjacent forest stands. A spatially constrained harvest scheduling model
called SSMART (Scheduling System of Management Alternatives foR Timber-harvest) is used for the analysis. It is one of the
heuristics to solve a spatially constrained harvest scheduling problem by using the partitioning heuristic. The algorithm
incorporated into SSMART is designed to seek a solution for a multicriteria problem with present net value maximum, meeting
spatial feasibility and minimizing period-to-period harvest flow fluctuation, approximating even-flow constraints within the
0–1 integer programming framework. Our experimental analysis shows that the longer exclusion period, the less the harvest
flow level and the total present net value are derived and the more heterogeneous the forest structure becomes in terms of
the forest stand age distribution. It is also shown that the three exclusion period results in a stable forest stand age distribution
over the time horizon for our experimental forest.
This research supported by the Grants-in-Aid for Scientific Research (No. 09041071) from the Ministry of Education, Science,
Sports, and Culture of Japan. 相似文献
25.
Atsushi IKEDA 《中国林业科技(英文版)》2002,(4)
Chinese fir (Cunninghamia lanceolata) and poplar (Populus spp.) wood meal were phenolated in the presence of sulfuric acid used as a catalyst. The effects of reaction time and reaction temperature on the wood liquefaction were investigated. The results showed that the reaction temperature had the greater influence on the residue content than reaction time. Additionally, the liquefaction curve for the Chinese fir and Poplar were similar in general. 相似文献
26.
The stem water conducting system of an evergreen broad-leaved oak, Lithocarpus edulis (Mak.) Nakai, was investigated. Evergreen broad-leaved oaks (Lithocarpus, Castanopsis, Cyclobalanopsis, Quercus) belonging to the Quercoideae are a major component of Asian monsoon forests, and are characterized by the possession of radial-porous wood. A characteristic of radial-porous wood is the development of aggregate rays between radially oriented files of vessels. We measured the distribution of vessel lumen diameters in a stem cross section and calculated the theoretical water conductivity of the wood. The radial profile of the heat pulse velocity (HPV) was measured for an intact whole tree under field conditions and compared with the theoretical distribution of water conductivity. Soft X-ray photographs of frozen stem sections indicated that most of the vessel lumina were filled with water, including those of vessels more than 20 years old. Even when vessels were relatively wide (lumen diameters > 100 microm), cavitation was negligible. The rate of water uptake from the cut stem base correlated closely with HPV (r = 0.96), and HPV closely reflected the mean volume flow per stem sectional area (SFVS) around the sensor probes. However, the ray tissue sharply inhibited heat transfer, and the positioning of the probes strongly affected the absolute value of HPV. It was also found that HPV more closely reflected the mean sap flow velocity in the vessels than did SFVS. 相似文献
27.
We investigated how shoot gross morphology and leaf properties are determined in Fagus japonica Maxim., a deciduous species with flush-type shoot phenology, in which all leaves are produced in a single flush at the start of each season. We examined relationships between current-year shoot properties and local light environment in a 14-m tall beech tree growing in a deciduous forest. Leaf number (LN), total leaf area (TLA), and total leaf length (SL) of the current-year shoot increased with increasing photosynthetic photon flux density (PPFD). Leaf thickness, dry mass per leaf area and nitrogen content on a leaf area basis increased, whereas the chlorophyll/N ratio decreased with increasing PPFD. To separate the effects of current-year PPFD from those of previous year(s), we artificially shaded a part of the uppermost leaf tier. Reciprocal transfers of beech seedlings between controlled PPFD regimes were also made. Characteristics of shoot gross morphology such as LN, TLA and SL were largely determined by the PPFD of the previous year. The exception was the length of the longest "long shoots" with many leaves, in which elongation appeared to be influenced by both previous-year and current-year PPFD. In contrast, leaf properties were determined by current-year PPFD. The ecological implications of our findings are discussed. 相似文献
28.
Jiro Sonoda Yuki Seki Atsushi Hakura Satoru Hosokawa 《Journal of toxicologic pathology》2015,28(2):109-120
Benzo[a]pyrene (BP) is mutagenic but noncarcinogenic in the murine colon. Recently, we reported rapid induction of colonic tumors by treatment of CD2F1 mice with BP (125 mg/kg for 5 days) followed by a colitis inducer, dextran sulfate sodium (DSS) (4% in drinking water for 1 or 2 weeks). However, there are no reports on detailed time course and histopathological features of colonic proliferative lesions in this model. Here, we show the detailed time course of colonic dysplasia, adenoma and adenocarcinoma induced by treatment with BP, DSS, and a combination of the two (BP/DSS). In the colon of mice exposed to BP/DSS, 14.6 dysplastic foci per mouse were present one week after DSS treatment (week 4). The number of dysplastic foci decreased with time to 3.1 at week 9 and thereafter remained almost constant. At week 4, 1.5 adenocarcinomas were also observed, with a marked increase in numbers with time, reaching 29.3 at week 14. In contrast, the number of dysplastic foci induced by DSS alone showed a time course similar to that following BP/DSS treatment; however, only a few tumors appeared. Neither dysplastic foci nor neoplastic lesions were induced by BP only. In mice exposed to BP/DSS, β-catenin was demonstrated immunohistochemically in the nucleus and/or cytoplasm of the tumor cells, and this translocation from the cell membrane was evident in subsets of dysplastic foci. In dysplastic foci induced by DSS alone, β-catenin was absent in the nucleus/cytoplasm. These finding suggest that aberrant β-catenin accumulation in dysplastic foci is associated with tumor progression in this BP/DSS model. 相似文献
29.
M. Shamim Hasan ZAHID Sharda Prasad AWASTHI Atsushi HINENOYA Shinji YAMASAKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(5):535-540
To search natural compounds having inhibitory effect on bacterial growth is important,
particularly in view of growing multidrug resistant (MDR) strains of bacterial pathogens.
Like other bacterial pathogens, MDR Vibrio cholerae, the causative agent
of diarrheal disease cholera, is becoming a great concern. As an approach of searching new
antimicrobial agents, here, we show that anethole, a well-studied natural component of
sweet fennel and star anise seeds, could potentially inhibit the growth of MDR O1 El Tor
biotype, the ongoing 7th cholera pandemic variant strains of toxigenic V.
cholerae. The minimum inhibitory concentration (MIC) of anethole against
diverse O1 El Tor biotype strains is evaluated as 200
µg/ml. Moreover, the effect of anethole is
bactericidal and exerts rapid-killing action on V.
cholerae cells. This study is the first report which demonstrates
that anethole, purified from natural compound, is a potent inhibitor of growth of
toxigenic V. cholerae. Our data suggest that anethole could be a
potential antimicrobial drug candidate, particularly against MDR V.
cholerae mediated infections. 相似文献
30.
Bhuminad DEVKOTA Masahiro TAKAHASHI Saori SATO Kouya SASAKI Atsushi UEKI Takeshi OSAWA Masahiro TAKAHASHI Norio YAMAGISHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(7):875-878
Blood samples were obtained sequentially from 10 dairy cows around the time of
parturition to assess plasma fluctuations in estradiol-17β (E2) levels in
association with those of several bone resorption markers. Plasma E2
concentration increased sharply a few days prepartum and decreased quickly after
parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant
acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and
was maintained at this level to a few days postpartum. The plasma concentration of
carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly
after parturition. These observations suggest that osteoclast-mediated bone resorption was
activated after parturition when plasma E2 concentrations decreased. 相似文献