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51.
Natsumi Kanzaki Takuya Aikawa Noritoshi Maehara Yu Ichihara 《Journal of Forest Research》2011,16(4):325-330
The pinewood nematode (PWN) Bursaphelenchus xylophilus is an invasive pathogen that was introduced from North America to Asian countries and Portugal and is devastating native
pine forests. Some native European and Asian Bursaphelenchus nematodes also have weak to moderate pathogenicity to native pine species. To evaluate the potential risk of native Bursaphelenchus species, we inoculated ten Japanese Bursaphelenchus species into native pine species (the dominant forest species) in Japan, and evaluated their pathogenicity using mortality
and tracheal tissue damage as indices. Inoculation was conducted on August 3, 2007, and the symptoms were observed every 2 weeks
until February 1, 2008. None of the inoculated trees, excluding the pathogenic PWN inoculated control, showed external disease
symptoms; however, four species [a less pathogenic PWN isolate, B. luxuriosae, Bursaphelenchus sp. NK215 (undescribed), and NK224 (undescribed)] caused tracheal tissue damage in inoculated seedlings and showed weak pathogenicity.
Therefore, we conclude that there are some potentially pathogenic native species of nematodes distributed in Japan. Interestingly,
two of these weakly pathogenic species, B. luxuriosae and NK215, are not associated with Pinaceae trees, suggesting that nematode pathogenicity may be a pre-adaptive character.
More experimental studies under different conditions are necessary to accurately evaluate the potential risk of these pathogens. 相似文献
52.
To clarify the pathogenicity of Bursaphelenchus nematodes to adult pine trees, inoculation experiments using six species of B. xylophilus group nematodes and ca. 10‐year‐old trees of Pinus thunbergii were conducted. Trees inoculated with an avirulent isolate (C14‐5) of B. xylophilus did not die during the survey, but showed a decline in oleoresin exudation compared with the controls. Fifteen months after the inoculation, a small number of B. xylophilus survived in a tree inoculated with B. xylophilus C14‐5. Trees inoculated with B. mucronatus, B. doui, B. luxuriosae, B. conicaudatus and Bursaphelenchus sp. NK224 (undescribed) showed no decline in oleoresin exudation and no external symptoms of wilt. However, 9 months after the inoculation, a small number of B. luxuriosae survived in a tree inoculated with the nematodes, although four other nematode species were not isolated from trees inoculated with them. These results were approximately consistent with our previous results (Kanzaki, N.; Aikawa, T.; Maehara, N.; Ichihara, Y., 2010, J. For. Res.; in press), in which an avirulent isolate (OKD‐1) of B. xylophilus and B. luxuriosae caused water flow inhibition without external symptoms in 3‐year‐old seedlings. Therefore, to examine the pathogenicity of the nematodes to pines, it is useful to use 3‐year‐old seedlings in inoculation experiments when adult trees cannot be used. 相似文献
53.
Yoshikawa T Moriyama A Kodama R Sasaki Y Sunagawa T Okazaki T Urashima A Nishida Y Arima A Inoue A Negishi T Yoshikawa Y Ihara T Maeda H 《Journal of toxicologic pathology》2011,24(4):215-222
To evaluate morphologic alterations in the thyroid gland in the second generation in cynomolgus monkeys, pregnant dams were exposed to high doses of thiamazole. In Experiment A, dams received thiamazole intragastrically via a nasogastric catheter from gestation day (GD) 50 to GD 150 or on the day before delivery. Initially, the dose level was 20 mg/kg/day (10 mg/kg twice daily); however, the dose level was subsequently decreased to 5 mg/kg/day (2.5 mg/kg twice daily), since deteriorated general conditions were observed in two dams. Six out of seven neonates died on the day of birth. The cause of neonatal death was tracheal compression and suffocation from goiter. The transplacental exposure to thiamazole affected the fetal thyroid glands and induced goiter in all neonates. The surviving neonate was necropsied 767 days after discontinuation of thiamazole exposure and showed reversibility of the induced changes. In Experiment B, dams were intragastrically administered thiamazole at 5 mg/kg/day (2.5 mg/kg twice daily) for treatment periods from GDs 51 to 70, 71 to 90, 91 to 110, 111 to 130 and 131 to 150. All fetuses showed enlarged thyroid glands but were viable. Histopathologically, hypertrophy and/or hyperplastic appearance of the follicular epithelium of the thyroid gland was observed at the end of each treatment period. The most active appearance of the follicular epithelium, consisting of crowded pedunculated structure, was demonstrated at end of the treatment period from GD 131 to 150. This is the first report on the morphology of fetal and neonatal goiter in the cynomolgus monkey. 相似文献
54.
Exposure to primaquine for 48 hours caused lesions in the exoerythrocytic stages of Plasmodium fallax grown in cultivated cells derived from embryonic turkey brain. The lesions appeared in the form of cytoplasmic vacuoles when viewed under the light microscope. The electron microscope revealed these vacuoles as swollen mitochondria readily identifiable by their typical protozoan cristae. Mitochondria of the host cell were unaffected. 相似文献
55.
56.
Takeshi Yamamoto Nobuhiro Suzuki Hirofumi Furuita Tsuyoshi Sugita Natsumi Tanaka Takanobu Goto 《Fisheries Science》2007,73(1):123-131
A feeding experiment was conducted to evaluate the supplemental effect of bile salts to a defatted soybean meal-based non-fish
meal diet for rainbow trout Oncorhynchus mykiss. A fish meal-based diet (FM) and two non-fish meal diets with and without bovine bile salts (SC+B and SC, respectively) were
fed to fish (13 g initial weight) for 10 weeks. Fish fed diet SC showed inferior growth and feed efficiency, while bile salt
supplementation improved the parameters to the same levels as fish fed diet FM. Crude fat and starch digestibility of diet
SC-fed fish decreased after the 10-week feeding trial compared to the data obtained with fish that had no experience of the
diet. Total biliary bile salt content and intestinal maltase activity of fish fed diet SC were the lowest among treatments,
while these parameters were improved by bile salt supplementation. Morphological changes occurred in the distal intestine
and liver of the diet SC group, although the histological features of fish fed diet SC+B were similar to those of fish fed
diet FM. These results suggest that bile salt supplementation to a soybean meal-based diet improves the nutrient utilization
by normalizing digestive processes in rainbow trout. 相似文献
57.
58.
The shear strength of dowel-type timber connections with multiple slotted-in steel plates was estimated based on European
yield theory. The values calculated based on the yield theory were compared with experimentally obtained results. An experiment
was performed on dowel-type timber connections with two and three slottedin steel plates under lateral loads parallel to the
grain. The yield mode of the dowel-type connection assumed in this study corresponds approximately to the failure mode of
the connection obtained from the experiment. The shear strength of the dowel-type connections calculated based on the yield
theory showed good agreement with the results for shear strength obtained in the experiment. The yield theory was useful for
estimating the shear strength of the doweltype connection with multiple slotted-in steel plates. The shear strength of the
dowel-type connection was greatly affected by the spacing of the steel plates, the number of steel plates, and the timber
thickness. The values of these parameters that showed the proper shear strength of the dowel-type connection could be estimated
based on the yield theory.
Part of this paper was presented at the 9th Timber Engineering Forum of the Japan Timber Engineering Society, December 2005 相似文献
59.
Masahide Aikawa Motoharu Suzuki Takatoshi Hiraki Motonori Tamaki Akira Kondo Hitoshi Mukai Kentato Murano 《Water, air, and soil pollution》2007,182(1-4):91-105
We intensively surveyed the concentrations of chemical species in aerosols and gases using a four-stage filter-pack method at a site in Japan facing the Sea of Japan in winter with 6-h sample intervals. A few chloride species emitted anthropogenically were detected, and the HCl (g) concentration was quite low. The number of chloride species artifacts was also low. The HNO3 (g) concentration was significantly higher when the monitored air mass passed over the Korean Peninsula compared to when it did not pass over the Korean Peninsula. In addition, the HNO3 (g) concentration was significantly higher when the air mass arrived at the monitoring site by passing the route at lower latitude than the latitude of the monitoring site. On the other hand, the SO2 (g) concentration showed no change between various trajectories of the air mass. The $ {\text{NH}}^{ + }_{4} $ (p)/non-seasalt- (nss-) $ {\text{SO}}^{{2 - }}_{4} $ (p) ratio was intermediate between the compositions of (NH4)2SO4 and NH4HSO4 when the air mass passed over the Korean Peninsula, whereas it was intermediate between NH4HSO4 and H2SO4 when the air mass did not pass over the Korean Peninsula. We detected the transboundary transport of sulfur dioxide with high time-resolution monitoring at two separate monitoring points: the current monitoring site and Oki Island. 相似文献
60.
Shuhei?Takemoto Hitoshi?Nakamura Masanobu?TabataEmail author Atsuko?Sasaki Yu?Ichihara Takuya?Aikawa Toshiyuki?Koiwa 《Journal of General Plant Pathology》2012,78(1):77-79
In early August 2010, lacquer trees (Toxicodendron vernicifluum) severely damaged by a root rot disease were found on plantations in Iwate, Japan. The causal agent was a fungus identified
as Rosellinia necatrix, based on morphology and the sequence of the ribosomal DNA internal transcribed spacer region. The fungus was clearly pathogenic
on T. vernicifluum root plantings. This report is the first of white root rot on T. vernicifluum. 相似文献