Importance of shingle beaches as habitat for Manila clam Ruditapes philippinarum     

Ichimi  Kazuhiko  Honda  Miyuki  Okada  Yuka  Tsuzuki  Kana  Yamaguchi  Hitomi 《Fisheries Science》2019,85(3):417-427

Fisheries Science - We carried out surveys to clarify how the density (no. of individuals/m2) and condition factor (CF) of Manila clam Ruditapes philippinarum differ between estuarine tidal flats...  相似文献   

Pathological characteristics of thyroid glands from Japanese Black Cattle living in the restricted area of the Fukushima Daiichi Nuclear Power Plant accident     

Jun Sasaki  Megumi Uehara  Itaru Sato  Hiroshi Satoh  Yoshitaka Deguchi  Hiroyuki Chida  Masahiro Natsuhori  Takahisa Murata  Kenji Ochiai  Kumiko Otani  Keiji Okada  Nobuhiko Ito 《Animal Science Journal》2019,90(9):1333-1339

To study the effect of ionizing radiation on thyroid glands, 66 Japanese Black cattle residing in the restricted area of the Fukushima Daiichi Nuclear Power Plant in 2013–2017 were pathologically examined. There were no clinical symptoms of thyroid disease in these cattle. Three cases of goiter and seven of atrophy were found in two among the four farms examined. Cases of goiter exhibited normal morphological structure without mass or nodule formation in thyroid glands. Cellular atypia or capsular invasion of the follicular epithelium was absent. The estimated integrated dose of external radiation in goiter cases ranged from maximum 797 mSv to minimum 24 mSv. All lobules in the seven atrophic thyroid glands were affected, but pathological findings, such as inflammatory cell infiltration or stromal fibrosis, were not observed. The estimated integrated dose of external radiation in atrophic thyroids ranged from maximum 589 mSv to minimum 8 mSv. Immunohistochemical analysis of anti‐nitroguanosine and the TUNEL method in goiter and atrophic thyroid glands did not reveal any positive findings. The present study indicates that there was no significant relationship between a radiation effect and pathological findings in any thyroid glands.  相似文献   

Comparison of urine and blood as a convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium     

Itaru Sato  Jun Sasaki  Hiroshi Satoh  Masahiro Natsuhori  Takahisa Murata  Keiji Okada 《Animal Science Journal》2019,90(8):1090-1095

Blood and urine were compared to clarify which is a better sample for estimating the concentration of radioactive cesium in muscles of live cattle. The most probable concentration of ¹³⁷Cs in muscles was 21.0 times that in blood, and the error of this estimation was 28%. The concentration of ¹³⁷Cs in blood was estimated accurately using urine samples. The estimation error did not increase so much (33%), even when the concentration of ¹³⁷Cs in muscles was estimated using urine samples. On the other hand, the maximum volume of blood that can be collected with one syringe is 50 ml, whereas it is easy to collect 1,000 ml of urine. It took at least 360 min to confirm that a cow meets the legal standard by inspecting 50 ml of blood. However, with 1,000 ml of urine, a 20 min measurement time was sufficient for this purpose. This difference in the required measurement time is critically important for practical use. In addition, urine can be collected by farmers themselves, whereas the blood collection requires a veterinarian. Therefore, urine is a more convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium.  相似文献   

Decreased blood cell counts were not observed in cattle living in the “difficult‐to‐return zone” of the Fukushima nuclear accident     

Itaru Sato  Jun Sasaki  Hiroshi Satoh  Yoshitaka Deguchi  Hiroyuki Chida  Masahiro Natsuhori  Kumiko Otani  Keiji Okada 《Animal Science Journal》2019,90(1):128-134

White blood cells, especially lymphocytes, are susceptible to radiation exposure. In the present study, red blood cell, total white blood cell, and lymphocyte counts were repeatedly measured in cattle living on three farms located in the “difficult‐to‐return zone” of the Fukushima nuclear accident, and compared with two control groups from unaffected areas. Blood cell counts differed significantly between the two control groups, although almost all the values fell within the normal range. The blood cell counts of the cattle in the “difficult‐to‐return zone” varied across sampling times even on the same farms, being sometimes higher or lower than either of the two control groups. However, neither a statistically significant decrease in blood cell counts nor an increase in the rate of cattle with extremely low blood cell counts was observed overall. The estimated cumulative exposure dose for the cattle on the most contaminated farm was within a range of 500–1000 mSv, exceeding the threshold for the lymphopenia. Because of the low dose rate on these farms, potential radiation damages would have been repaired and have not accumulated enough to cause deterministic effects.  相似文献   

Oxidative stress and bovine liver diseases: role of glutathione peroxidase and glucose 6-phosphate dehydrogenase   总被引：1，自引：0，他引：1  

Abd Ellah MR  Okada K  Yasuda J 《The Japanese journal of veterinary research》2007,54(4):163-173

This article summarizes the different types of free radicals, antioxidants and the effect of oxidative stress on the activities of glutathione peroxidase and glucose 6-phosphate dehydrogenase in bovine liver diseases. A growing body of evidence suggests that the formation of reactive oxygen species is a common occurrence associated with most if not all disease processes. The overall importance of reactive oxygen species to the progression and severity of various disease states varies greatly depending on the conditions and whether the disease is acute or chronic. Free radical researches in animals are in progress and further investigations are needed to establish the involvement of reactive oxygen species in diseases affecting different animal species and the pathology they produce.  相似文献   

Interspecific differences in the post-settlement survival of <Emphasis Type="Italic">Acropora</Emphasis> corals under a common garden experiment     

Go Suzuki  Wataru Okada  Youko Yasutake  Sayaka Kai  Yuji Fujikura  Iwao Tanita  Hiroshi Yamashita  Takeshi Hayashibara  Wataru Ando  Koichi Nogami  Masayuki Fudo 《Fisheries Science》2018,84(5):849-856

Extremely low post-settlement survival is one of the largest barriers for artificial rehabilitation of Acropora corals. However, little data have been found for interspecific difference of the post-settlement survival probably because the observation of coral juvenile is difficult in the field. Here, we analyzed the survival of three dominant species of Acropora corals (A. digitifera, A. tenuis, A. yongei), with different colony morphologies and habitat preferences, for 2 years after settlement under the same environmental conditions. The post-settlement survival was significantly higher for A. tenuis than for A. digitifera 3 months after settlement. Two years later, the survival rate of A. tenuis was approximately 15 times higher than A. digitifera. In a separate analysis of three bottle-brush species (A. awi, A. echinata, A. subglabra) and A. tenuis, post-settlement survival was always higher for A. awi than for other two bottle-brush species, suggesting that the initial survival was different among morphologically sister species. Low survival was possibly associated with slow growth rates during the first 7 months. Thus, species selection is important for successful artificial coral rehabilitation, with A. tenuis being the most viable option. Alternatively, new techniques are required to improve post-settlement survival of slow growing coral species.  相似文献   

First feeding of diploid and triploid yellowtail tetra Astyanax altiparanae: An initial stage for application in laboratory studies          下载免费PDF全文

Rafaela Manchin Bertolini  José Augusto Senhorini  Nivaldo Ferreira do Nascimento  Matheus Pereira‐Santos  Laura Satiko Okada Nakaghi  Wellington Adriano Moreira Peres  Regiane Cristina da Silva  George Shigueki Yasui 《Aquaculture Research》2018,49(1):68-74

In this study, the aim was to establish a protocol for first feeding of diploid and triploid yellowtail tetra Astyanax altiparanae in laboratory conditions. The fry were fed with five different diets: (i) Artemia franciscana nauplii, (ii) plankton, (iii) dry food, (iv) Artemia franciscana nauplii + plankton, and (v) Artemia nauplii + plankton + dry food. Additionally, the growth and survival rates of diploid and triploid individuals were also evaluated. On day 10, the length of the fish between the treatments differed significantly (p = .0001) and ranged from 4.07 ± 0.06 mm (dry food) to 8.50 ± 0.64 mm (plankton + Artemia). The sizes of the fish increased with time, except for the fish fed with dry food. The survival rates were similar for the fish fed with the four diets and ranged from 80.7 ± 5.4% (dry food + plankton + Artemia to 92.0 ± 1.6% (plankton + Artemia), but differed from the fish fed with dry food (17.7 ± 5.8%, p = .0017). Diploids and triploids did not present differences on day 0 (p = .2252) and on day 10 (p = .4844) when the fish presented 6.77 ± 0.25 mm and 6.54 ± 0.15 mm respectively. Survival of diploids (87.3 ± 5.13%) and triploids (74.67 ± 2.30%) were also similar (p = .0285). These data are innovative and useful for establishing protocols for this species in both academic and applied sciences.  相似文献   

Rot diseases of carrot and rapeseed caused by Typhula species under snow in Hokkaido,Japan     

Sachiko Ikeda  Tamotsu Hoshino  Naoyuki Matsumoto  Norio Kondo 《Journal of General Plant Pathology》2016,82(5):286-291

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Evolution and spread of glyphosate resistance in Conyza bonariensis in California and a comparison with closely related Conyza canadensis          下载免费PDF全文

M Okada  B D Hanson  K J Hembree  Y Peng  A Shrestha  C N Stewart Jr  S D Wright  M Jasieniuk 《Weed Research》2015,55(2):173-184

Glyphosate‐resistant weeds are an increasing problem in perennial cropping systems in the Central Valley of California, USA. To elucidate the evolutionary origins and spatial spread of resistance, we investigated the geographical distribution of glyphosate resistance and the population genetic diversity and structure of Conyza bonariensis and compared the results with previously studied C. canadensis. Thirty‐five populations from orchards and vineyards across the Central Valley were sampled. Population genetic structure was assessed using microsatellite markers. Population‐level resistance was assessed in glasshouse screening of plants grown from field‐collected seed. Bayesian clustering and analyses of multilocus genotypes indicated multiple origins of resistance, as observed in C. canadensis. Pairwise F_ST analysis detected spatial spread of resistance in the south of the Central Valley, also similar to C. canadensis. The results strongly indicate that the southern valley was an environment markedly more suitable than the northern valley for resistance spread and that spread in Conyza species was driven by increased uniformity of strong selection in the southern valley, due to recent regulation on herbicides other than glyphosate. Accordingly, resistant C. canadensis individuals occurred at high frequencies only in the southern valley, but interestingly resistant C. bonariensis occurred at high frequencies throughout the valley. Expression of resistance showed varying degrees of plasticity in C. bonariensis. The lower selfing rate and substantially greater genotypic diversity in C. bonariensis, relative to C. canadensis, indicate greater evolutionary potential over shorter time periods. Interspecific hybridisation was detected, but its role in resistance evolution remains unclear.  相似文献   

Effects of sika deer (Cervus nippon) and dwarf bamboo (Sasamorpha borealis) on seedling emergence and survival in cool-temperate mixed forests in the Kyushu Mountains     

Ikue Murata  Sigefumi Saruki  Katsuyoshi Kubota  Sachiko Inoue  Naoaki Tashiro  Tsutomu Enoki  Yasuhiro Utsumi  Susumu Inoue 《Journal of Forest Research》2009,14(5):296-301

Effects of sika deer (Cervus nippon) and dwarf bamboo (“sasa;” Sasamorpha borealis) on seedling emergence and survival were investigated in cool-temperate mixed forests in the Kyushu mountain range, Japan. We compared the effects of sika deer between two sites with different sika deer densities. One site (no-sasa forest) has sparse cover of S. borealis and a high density of sika deer, and the other site (sasa forest) has dense cover of S. borealis with a low density of sika deer. In the no-sasa forest, more seedlings emerged and the survival rate of the seedlings was higher compared with the sasa forest. Compared with the sasa forest, the canopy in the no-sasa forest was more open, the organic layer was shallower and drier, the mean daily soil temperature was higher, and soil temperature fluctuated more widely. Those environmental parameters did not differ between unfenced and fenced plots. The comparison between the sasa and no-sasa forests suggested that removal of S. borealis by sika deer had an indirect positive effect on seedling emergence and survival. However, the fenced-plot experiments indicated that sika deer inhibited seedling emergence and survival. These contradictory conclusions could result from the much larger negative effects of S. borealis on seedling emergence and survival compared with the effects of sika deer browsing.  相似文献