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171.
Nguyen ST Honma H Geurden T Ikarash M Fukuda Y Huynh VV Nguyen DT Nakai Y 《Research in veterinary science》2012,93(2):848-852
We investigated the prevalence and risk factors associated with Cryptosporidium oocysts shedding in pigs in Central Vietnam. A total of 740 single fecal samples collected from diarrheic and non-diarrheic pigs on 89 farms were screened by the modified Ziehl-Neelsen staining method. Prevalence at the animal and the farm levels were 18.1% (134/740) and 71.9% (64/89), respectively. Risk factors for the infection were identified using univariate and multivariate logistic regression analysis. The results revealed that age, sanitary condition and topography were significantly associated with oocyst shedding (P<0.05). Pre-weaned piglets were at the highest risk for infection, followed by post-weaners, sows and finishing pigs. Good sanitary conditions showed positive effects in decreasing oocysts shedding. Topographically, Cryptosporidium was more common in mountainous zone than that in coastal delta zone. There was an association between the occurrence of diarrhea and the level of Cryptosporidium oocyst excretion within infected pigs. This is the first epidemiological investigation of prevalence and risk factors of Cryptosporidium in pigs in Vietnam. 相似文献
172.
Sam Thi Nguyen Duc Tan Nguyen Thoai Van Nguyen Vu Vy Huynh Duc Quyet Le Yasuhiro Fukuda Yutaka Nakai 《Tropical animal health and production》2012,44(8):1847-1853
The aims of this study were to investigate the prevalence of natural Fasciola infections in both the definitive hosts (cattle) and the intermediate hosts (Lymnaea snails) in central Vietnam. A total of 1,075 fecal samples, randomly collected from cattle in Binh Dinh, Khanh Hoa, and Phu Yen provinces, were examined for Fasciola eggs by a sedimentation method. The overall prevalence of Fasciola was 45.3?%. A subset of the animals (235) was also screened for antibodies against Fasciola by an enzyme-linked immunosorbent assay. Overall, 46.3?% of these animals were shedding Fasciola eggs while 87.2?% were Fasciola seropositive. A lower prevalence of Fasciola was observed in calves ??2?years of age (37.6?%) compared to that in cattle >2?years of age (53.7?%) (p?<?0.05). The prevalence in the rainy season (50.8?%) was significantly different to that in the dry season (38.1?%) (p?<?0.05). Of the 3.269 Lymnaea viridis and 1.128 Lymnaea swinhoei examined, 31 (0.95?%) and seven (0.62?%), respectively, were found to be infected with Fasciola. This appears to be the first epidemiological survey of the prevalence of Fasciola in cattle and snails in these three provinces in central Vietnam. 相似文献
173.
Subtropical forests in the Ryukyu Islands have been degraded by silvicultural practices, and thus their structural attributes
are being shifted to other states dominated by a few tree species. This study clarified the mechanisms of the change, and
examined the effect of clear logging on the resilience of a subtropical forest. Sprouting regeneration and typhoon disturbance
were introduced into an individual-based model, SEIB-DGVM, for describing stand development and succession. The regeneration
dynamics from young secondary to old-growth stands were reproduced fairly well with the model. Sprouting recruitment produced
high stem density at the beginning of stand development, which caused a self-thinning trajectory following the −3/2 power
law. In the late development stage after 70 years, tree species diversity fluctuated because of the regenerative response
of sprouting species and the facilitatory effect of typhoon disturbance on the coexistence of subordinate species. The death
of canopy trees because of typhoon disturbances reduced the dominance of Castanopsis sieboldii, and depressed its dominance in the understory. Consequently, the understory species could establish by virtue of fallen
canopy trees, and tree species diversity increased at the stand level. Clear logging experiments in the model revealed that
species diversity deteriorated, especially in the stand dominated by sprouting species. Resilience of subtropical forests
was determined by initial species composition before clear logging. Our simulation results suggest that repeated logging drives
subtropical forests with high species diversity to a stand monopolized by C. sieboldii. 相似文献
174.
Masaharu Kubota Osamu Tamura Yasuhiro Nomura Noriko Orihara Norihito Yamauchi Kengo Yonemoto Kenichiro Chiba Nobutaka Someya 《Journal of General Plant Pathology》2017,83(2):117-120
Isolates of spinach downy mildew fungus, Peronospora farinosa f. sp. spinaciae, collected at seven sites in Japan from December 2013 to March 2016, were identified as belonging to races 8, 10, 12 and 13, and one was unauthorized. Races 10, 12, 13 and the unauthorized were first found in Japan. 相似文献
175.
176.
Shogo Higaki Takaaki Todo Reiko Teshima Ikuo Tooyama Yasuhiro Fujioka Noriyoshi Sakai Tatsuyuki Takada 《Fish physiology and biochemistry》2018,44(2):503-513
We investigated the feasibility of cryopreservation of spermatogonia and oogonia in the critically endangered cyprinid honmoroko Gnathopogon caerulescens using slow-cooling (freezing) and rapid-cooling (vitrification) methods. Initially, we examined the testicular cell toxicities and glass-forming properties of the five cryoprotectants: ethylene glycol (EG), glycerol (GC), dimethyl sulfoxide (DMSO), propylene glycol (PG), and 1,3-butylene glycol (BG), and we determined cryoprotectant concentrations that are suitable for freezing and vitrification solutions, respectively. Subsequently, we prepared the freezing solutions of EG, GC, DMSO, PG, and BG at 3, 2, 3, 2, and 2 M and vitrification solutions at 7, 6, 5, 5, and 4 M, respectively. Following the cryopreservation of the testicular cells mainly containing early-stage spermatogenic cells (e.g., spermatogonia and primary spermatocytes), cells were cultured for 7 days and immunochemically stained against germ cell marker protein Vasa. Areas occupied by Vasa-positive cells indicated that vitrification led to better survival of germ cells than the freezing method, and the best result was obtained with 5 M PG, about 50% recovery of germ cells following vitrification. In the case of ovarian cells containing oogonia and stage I, II, and IIIa oocytes, vitrification with 5 M DMSO resulted the best survival of oogonia, with equivalent cell numbers to those cultured without vitrification. The present data suggest that male and female gonial cells of the endangered species G. caerulescens can be efficiently cryopreserved using suitable cryoprotectants for spermatogonia and oogonia, respectively. 相似文献
177.
Defining the spatial arrangement and length of the cutting cycle in a logged area is crucial for reconciling potential conflicts
between timber yields and maintenance of ecosystem services in natural forests. In this study, we investigated long-term impacts
of clear-fell logging on timber production and tree species diversity in a subtropical forest on the Ryukyu Islands, using
an individual-based simulation model. We assumed six logging scenarios defined by combinations of forest type and regeneration
processes, which acted as surrogates for spatial scales of clear-fell logging. These scenarios were simulated under cutting
cycles ranging from 20 to 150 years. Short-cutting cycles resulted in dominance by the sprouting species Castanopsis sieboldii. The compositional shift was accelerated by the lack of seed dispersal from surrounding forest areas. The simulations demonstrated
that a sustainable logging regime maintaining both yield and tree species diversity requires a cutting cycle longer than 50 years.
The simulation results also suggest that the trade-off between the recovery of tree species diversity and timber production
is favored more in stands surrounded by mature forest than in isolated stands or stands surrounded by immature forest. Ecological
risk assessments based on model simulations provide an alternative to current forest management practices that rely on empirical
knowledge. 相似文献
178.
179.
Kodama R Yang X Araki T Sato M Iwashige S Tanigawa Y Uchimura M Ishimaru K Sasaki Y Kamimura Y Maeda H 《Journal of toxicologic pathology》2010,23(1):53-58
In a seven-year-old male cynomolgus monkey, erythema of the upper eyelid and forehead and corneal opacity, edema and conical protrusion in the eye were observed. At necropsy, ophthalmological and serological examinations revealed binocular corneal opacity and conical protrusion and a high IgE level, respectively. Thinning of the epithelium and stroma of the cornea were noted histopathologically. At the center of the corneal epithelium, the number of epithelial cells was reduced, their cytoplasm was poorer and the basal cells were flatter than at the periphery. Bowman's membrane was folded with partial loss or breakage. Collagen fibers were compacted or disarranged, and the keratocytes were increased in the stroma, with focal pyknosis or loss of the endothelium and folding of Descemet's membrane. Electron microscopical examination revealed atrophy of the corneal epithelial basal cells. This is the first report of a case of keratoconus in a cynomolgus monkey. 相似文献
180.
Mitsuo Horita Yasuhiro Suga Atsushi Ooshiro Kenichi Tsuchiya 《Journal of General Plant Pathology》2010,76(3):196-207
We assessed the geographic distribution, biovar, phylotype, DNA fingerprints (rep-PCR), and/or endoglucanase sequence of potato
bacterial wilt pathogen, Ralstonia solanacearum (Rs), in Japan. Rs has been isolated from potato fields in southwestern, warm, temperate regions. Of the 188 isolates, 74
belonged to biovar N2 (39%), 44 to biovar 3 (24%), and 70 to biovar 4 (37%). Biovars N2 and 4 strains were widely distributed,
from northern (Hokkaido) to southern (Okinawa) Japan. Based on the results of multiplex-PCR analysis, every potato strains
belonged to either phylotype I or IV. Phylotype I comprised both biovars 3 and 4 strains. On the other hand, phylotype IV
included biovar N2 strains. None of the strains belonged to phylotype II or III or biovar 1 or 2. Phylogenetic analysis based
on DNA fingerprints and endoglucanase gene sequences clarified the genetic diversity of the Japanese potato strains and the
close genetic relationship between the Japanese strains and the Asian strains in phylotypes I and IV. 相似文献