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41.
Sho Morimoto Tomoko Uchida Hisaya Matsunami Hiroyuki Kobayashi 《Soil Science and Plant Nutrition》2013,59(5):545-553
Winter cover crops increase the amount of indigenous arbuscular mycorrhizal fungi (AMF) in the soil, providing beneficial effects such as enhancement of phosphorus uptake by the subsequent crop. However, its impact on the AMF community structure is not well understood. In the present study, we aimed to reveal the effect of winter wheat cover cropping with no-till cultivation on the AMF community structures in soil and roots of the subsequent soybean. For this purpose, we conducted a field experiment consisting of two treatments, no-till soybean cultivation after winter wheat cover cropping (NTWC) and conventional soybean cultivation after winter fallow management as a control (CONT). At the flowering stage of soybean, higher AMF colonization of soybean roots was observed in the NTWC plots compared with the CONT plots. Additionally, aboveground biomass and phosphorus uptake of soybean in the NTWC plots were significantly higher than those in the CONT plots. Molecular community analyses based on PCR-denaturing gradient gel electrophoresis (DGGE) of AMF 18S rRNA genes indicated that the AMF community structures in the soil and soybean root of the NTWC plots were clearly different from those of the CONT plots. The DGGE profiles showed that the wheat cover cropping preferentially increased some phylotypes belonging to Glomeraceae and Claroideoglomeraceae. In addition, most of the phylotypes were characteristically observed in the subsequent soybean root of the NTWC plots, strongly suggesting that these phylotypes colonizing the cover crop wheat were taken over by the subsequent soybean. Our study revealed the significant effect of winter cover cropping with no-till cultivation on the structure of AMF community colonizing the subsequent soybean. 相似文献
42.
This paper describes the features of binderless particleboard manufactured from sugarcane bagasse, under a high pressing temperature of 200–280 °C. Mechanical properties [i.e., modulus of rupture (MOR) and elasticity (MOE) in dry and wet conditions, internal bonding strength (IB)] and dimensional stability [i.e., thickness swelling (TS)] of the board were evaluated to investigate the effect of high pressing temperature. Recycled chip binderless particleboards were manufactured under the same conditions for comparison, and particleboards bonded with polymeric methylene diphenyl diisocyanate (PMDI) resin were manufactured as reference material. The target density was 0.8 g/cm3 for all of the boards. The results showed that the mechanical properties and dimensional stability of both types of binderless boards were improved by increasing the pressing temperature. Bagasse showed better performance than that of recycled chip as a raw material in all evaluations. Bagasse binderless particleboard manufactured at 260 °C had an MOE value of 3.5 GPa, which was equivalent to the PMDI particleboard, and a lower TS value of 3.7 % than that of PMDI particleboard. The MOR retention ratio under the dry and wet conditions was 87.0 %, while the ratio for the PMDI particleboard was only 54.6 %. The obtained results showed the possibility of manufacturing high-durability binderless particleboard, with good dimensional stability and water resistance, which previously were points of weakness for binderless boards. Manufacturing binderless boards under high temperature was effective even when using particles with poor contact area, and it was possible to express acceptable properties to allow the manufacture of particleboards. Further chemical analysis indicated a contribution of a saccharide in the bagasse to the improvement of the board properties. 相似文献
43.
Shinji Yamamoto Atsuhiko Fukushima Katsuya Ishimaru Sho Shirakashi 《Fisheries Science》2014,80(5):1021-1026
The skin fluke Neobenedenia girellae has become a serious problem in Japan since the 1990s. Present control methods focus on the removal of the attached parasite and these post-infection treatments are often labor intensive, time consuming, and/or stressful to fish. Chub mackerel Scomber japonicus are highly susceptible to N. girellae. However, because of their sensitive nature, bath treatments may cause mortality. In this study, we investigated the efficacy of cage shading to reduce skin fluke infection and the frequency of conventional post-infection treatments. Juvenile mackerel were reared in cages with or without shade for 3 months and their skin fluke infections were monitored. We performed either freshwater baths or oral administration of praziquantel if fluke intensity exceeded the given criteria. In unshaded cages, 3 total bath treatments or 6 total drug treatments were conducted. In contrast, no treatment was required for the shaded cage. The overall fluke intensity in the shaded cage was less than half that of the unshaded cages, despite the lack of treatments. This study demonstrated for the first time the practical use of shading in fish farms to reduce skin fluke infection. 相似文献
44.
Sho FUKUI Yoshifumi ENDO Kazuko HIRAYAMA Hiroyuki TANIYAMA Tsuyoshi KADOSAWA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(6):747-751
Simultaneous removal of bilateral thyroid tumors was performed while preserving the
parathyroid gland in six dogs. At least one external parathyroid gland was identified in
all dogs. In five cases, the external parathyroid gland and its blood supply were
preserved intact. In one dog, the vessels supplying the external parathyroid gland had
been invaded by the tumor, and the gland was thus removed and reimplanted into the
sternohyoid muscle. That dog required postoperative treatment with oral calcium gluconate
and vitamin D3. Local tumor recurrence was not observed in any of the cases.
The mean survival time was 920 days. We found that the external parathyroid gland could be
identified and preserved in most dogs undergoing total thyroidectomy. 相似文献
45.
Evaluation of ABCG2 and p63 expression in canine cornea and cultivated corneal epithelial cells 下载免费PDF全文
46.
Spatial distribution analysis of the North Pacific spiny dogfish,Squalus suckleyi,in the North Pacific using generalized additive models 下载免费PDF全文
Toshikazu Yano Seiji Ohshimo Minoru Kanaiwa Tsutomu Hattori Masa‐aki Fukuwaka Toru Nagasawa Sho Tanaka 《Fisheries Oceanography》2017,26(6):668-679
The North Pacific spiny dogfish (SPD), Squalus suckleyi, is a commercially exploited shark species that plays an important role in the ecosystem. To elucidate the distribution of the SPD in the North Pacific and to evaluate the effects of sea surface temperature (SST) and prey availability on its distribution, we estimated the probability of SPD presence using a generalized additive model with a binomial error distribution from SPD presence/absence data on 14,824 operations in fishery‐independent gillnet surveys between 1972 and 2011. The habitat model was structured in the east and west to reflect differences in the North Pacific oceanic environments. In the east, a higher probability of SPD presence was identified along the coast from the eastern Gulf of Alaska to Queen Charlotte Sound. In the west, it was identified around northern Japan. The estimated distribution was continuous between the two areas, whereas the probability of SPD presence was relatively low. Although the probability of SPD presence was higher at SSTs between 6°C and 12°C, the SST at the peak probability of SPD presence differed between the west and east. The prey species, Japanese sardine, Sardinops melanostictus, and walleye pollock, Gadus chalcogrammus, in the west and boreal clubhook squid, Onychoteuthis borealijaponica, in the east significantly affected the probability of SPD presence, which was higher if the prey species co‐existed with SPD. Therefore, SPD might adapt their distribution to that of available prey species. SPD stock assessment and management in these two important areas are required for its sustainable utilization. 相似文献
47.
We monitored feeding behavior and survival of starved juvenile olive flounder experimentally infected with the gill monogenean
Neoheterobothrium hirame. Infected flounder increased amount of the time spent in the water column by 117% when trying to capture live mysids, Neomysis sp. They also showed different feeding patterns from those of uninfected fish and made fewer attacks towards prey during
one feeding attempt. Although the average numbers of mysids captured by individuals were similar between infected and uninfected
fish, heavily infected fish tended to catch less prey. These results indicate that N. hirame reduces the feeding efficiency of the host for capturing live prey and possibly makes them more vulnerable to predation during
feeding. We could not detect any obvious difference in survival rates between uninfected, lightly and heavily infected fish
during 3 months of starvation. There was no evidence that starvation makes fish more susceptible to N. hirame. The present study provides first experimental evidence that N. hirame affects feeding behavior of juvenile olive flounder and supports the idea that this parasite indirectly reducing the host’s
survival and may be responsible for the recent reduction of the flounder population in Japan. 相似文献
48.
WanXue Bao Takuya Nagasaka Shin Inagaki Sho Tatebayashi Iori Imazaki Shin-ichi Fuji Takashi Tsuge Masafumi Shimizu Koji Kageyama Haruhisa Suga 《Plant pathology》2020,69(5):901-910
Fusarium fujikuroi, the causative agent of bakanae disease in rice, produces many kinds of secondary metabolites. Recently, two phylogenetic subgroups (F and G groups) of Japanese F. fujikuroi have been identified and found to have differences in their gibberellin (GA) and fumonisin production. G-group F. fujikuroi produces large amounts of GA, but is a fumonisin nonproducer. F-group produces large amounts of fumonisin, but is a GA low or nonproducer. We investigated the cause of low GA production in the F-group. Genetic mapping suggests that low GA production in the F-group strain Gfc0825009 is due to a GA gene cluster for GA biosynthesis. Analysis of the nucleotide and amino acid sequences of the genes in the GA gene cluster showed >98.4% homology between the F-group strain Gfc0825009 and the G-group strain Gfc0801001. Following a 7-day culture under low nitrogen conditions, we found that expression of P450-1, P450-4, and P450-2 in the cluster increased in the G-group strain and not in the F-group strain. We hypothesized that complementation by GA genes in the G-group strain would be required to increase GA production in the F-group strain. However, we found that this occurred with a single gene complementation of DES, P450-1, P450-4, or P450-2. Simultaneous increase in the expression of P450-1, P450-4, and P450-2 were detected in the complementary transformants. Moreover, the same phenomenon was observed by reintegration of its own P450-1. Our results suggest the presence of unknown regulatory mechanisms of the GA gene cluster in F. fujikuroi. 相似文献
49.
Hiroko Akiyama Sho Morimoto Masahito Hayatsu Atsushi Hayakawa Shigeto Sudo Kazuyuki Yagi 《Biology and Fertility of Soils》2013,49(2):213-223
Agricultural soil is a major source of nitrous oxide (N2O), and the application of nitrogen and soil drainage are important factors affecting N2O emissions. This study tested the use of polymer-coated urea (PCU) and polymer-coated urea with the nitrification inhibitor dicyandiamide (PCUD) as potential mitigation options for N2O emissions in an imperfectly drained, upland converted paddy field. Fluxes of N2O and methane (CH4), ammonia oxidation potential, and ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) abundances were monitored after the application of PCU, PCUD, and urea to upland soil. The results showed that urea application increased the ammonia oxidation potential and AOB and AOA abundances; however, the increase rate of AOB (4.6 times) was much greater than that of AOA (1.8 times). These results suggested that both AOB and AOA contributed to ammonia oxidation after fertilizer application, but the response of AOB was greater than AOA. Although PCU and PCUD had lower ammonia oxidation potential compared to urea treatment, they were not effective in reducing N2O emissions. Large episodic N2O emissions (up to 1.59 kg N ha?1 day?1) were observed following heavy rainfall 2 months after basal fertilizer application. The episodic N2O emissions accounted for 55–80 % of total N2O emissions over the entire monitoring period. The episodic N2O emissions following heavy rainfall would be a major source of N2O in poorly drained agricultural fields. Cumulative CH4 emissions ranged from ?0.017 to ?0.07 kg CH4 ha?1, and fertilizer and nitrification inhibitor application did not affect CH4 oxidation. 相似文献
50.
Hiroshi Ashida Toshiyuki Tanabe Keisuke Satoh Atsushi Fukui Sho Tanaka Nobuhiro Suzuki 《Fisheries Science》2010,76(5):785-793
The reproductive biology of male skipjack tuna Katsuwonus pelamis was examined from May 2005 to December 2007 in the tropical western and central Pacific Ocean. Testis maturity was classified
into five stages (i.e., immature, early maturation, mid maturation, late maturation, and regression) on the basis of morphological
changes in the germinal epithelium. The testis duct system (TS), which was characterized by lobules that lack spermatocysts,
store only sperm, and form an anastomosing network, was located under the main sperm duct. The TS was observed at all stages
of maturity except the immature stage, and first appeared in individuals with a fork length (FL) of 38–40 cm. The estimated
minimum size at first maturity was 35.5 cm FL and the size at 0.5 maturity was 40.7 cm in FL. It was difficult to clearly
differentiate the testis maturity stage based solely on the gonad index (GI) class because each GI class contained mature
fish. Monthly changes in testis height index and GI did not follow a seasonal cycle. Mature individuals dominated throughout
the year. These results imply that male skipjack tuna in this area showed evidence of spawning activity throughout the year
without a clear seasonal pattern. 相似文献