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1.
Blood stream forms of drug-resistant and sensitive Trypanosoma brucei brucei, Trypanosoma brucei evansi and Trypanosoma vivax were incubated in a liquid medium for 24 h at 37 degrees C in the presence of various concentrations of diminazene aceturate (Berenil) or isometamidium chloride (Samorin), and assayed for infectivity in mice. Whereas the infectivity to mice of all Samorin-sensitive trypanosomes was decreased after incubation with 1 ng Samorin ml-1, the Samorin-resistant stocks remained infective for mice. Two of the Samorin-resistant stocks remained infective after incubation with Samorin concentrations of up to 50 ng ml-1. The infectivity of Berenil-resistant trypanosome stocks were also retained after incubation with drug concentrations (0.5 or 1.0 micrograms ml-1) which otherwise inhibited the infectivity of Berenil-sensitive trypanosome stocks. In addition, differences in infectivity were observed when Berenil-resistant and sensitive trypanosome stocks were incubated in medium supplemented with serum from goats previously treated with Berenil. Thus, drug-resistant and sensitive trypanosomes can be clearly distinguished using the drug incubation infectivity test. 相似文献
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Chuma T Maeda T Niwa H Okamoto K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(2):155-160
A dramatic rise in the number of resistant Campylobacter to quinolones has been documented in human patients and domestic animals. In this study, the mechanism of acquisition of quinolone resistance was studied by detecting point mutations in the gyrA gene of Campylobacter strains obtained from broilers and strains with in vitro-induced resistance. The minimal inhibitory concentrations (MICs) of norfloxacin (NFLX) and ofloxacin (OFLX) for the strains that had no point mutation were slightly increased from the source strain (Campylobacter jejuni ATCC 33560). The MICs of nalidixic acid (NA), NFLX, and OFLX for the strains that had the point mutation at Thr-86 were 100 or 200 microg/ml, 50 microg/ml, and 25 microg/ml, respectively. The MIC of NA for the strain that had a point mutation at Asp-90 higher than those for the strains that had the point mutation at Thr-86, but the MICs of NFLX and OFLX were relatively lower than those for the strains that had point mutation at Thr-86. These findings suggest that the degree of antimicrobial resistance against NA, NFLX, and OFLX in the in vitro-induced C. jejuni strains was associated with the location of the point mutation in gyrA. On the other hand, a point mutation in all seven resistant strains isolated from broilers was located only at Thr-86, while the MICs of the three quinolones varied in each wild strain. This suggests that another mechanism might also be involved in the acquisition of quinolone resistance in C. jejuni wild strains. 相似文献
3.
Yamamoto T Kobayashi S Nishiguchi A Nonaka T Tsutsui T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(2):137-142
Scattered SRM residues from BSE-infected cattle are possible to contaminate sewage during the slaughtering process in slaughterhouses. A proportion of the sludge discharged from wastewater treatment facilities at slaughterhouses has historically been processed into fertilizer. We therefore investigated the associated risk of BSE infection to cattle via sludge-derived fertilizer. Each stage of the process associated with BSE exposure was qualitatively evaluated and quantitative evaluations were subsequently performed using infectious dose as a unit of concern. Results of these qualitative evaluations indicated that installation of filter(s) at the drains to the wastewater treatment facilities has been undertaken by many slaughterhouses and has decreased the likelihood of SRM contamination of sewage. The level of sludge-derived fertilizer ingested by cattle was considered to be very low since the fertilizer is mixed with the ground soil, and the amount of soil ingested by cattle is likely to be small. Results from the quantitative analysis indicated the total infectious dose ingested by cattle in Japan from an infected cow has been estimated to be 5.5 x 10(-3) ID(50). Preventing scattering of SRM during the slaughtering process, installing filters to the drains with the removal of residues from the drain water and preventing the application of sludge-derived fertilizer to pasturelands would be effective to reduce the risk. Although the limited extent of available information, this study should provide useful indication for the development of an inclusive risk assessment for slaughterhouse sludge in the future. 相似文献
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Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, 'Nigrate', as a common parent of genetic crosses. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome. 相似文献
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Watanabe M Hisasue M Souma T Ohshiro S Yamada T Tsuchiya R 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(10):1095-1099
Detection of hemotropic Mycoplasma spp. infection was attempted in cats by PCR using whole blood without DNA extraction. A total 46 of 54 (85%) cats with suspected Mycoplasma spp. infection showed a positive reaction, corresponding completely with the results of standard PCR testing. The direct PCR assay was sensitive enough to detect more than 0.0061% parasitemia for ;C. M. haemominutum' and 0.0075% parasitemia for M. haemofelis. These data indicate that the direct PCR assay might be sufficient for use as a tool in clinical examinations. 相似文献
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Seiji Shimoda Shohei Murayama Wenhong Mo Takehisa Oikawa 《Agricultural and Forest Meteorology》2009,149(3-4):603-613
Measurements of δ13C in atmospheric CO2 and plant samples were made in 2003, along with CO2 flux measurements, at a grassland site in Tsukuba in central Japan. The objective of the study was to obtain estimates of relative seasonal contributions of C3 and C4 plants to the net CO2 flux over a C3/C4 grassland area influenced by the Asian monsoon. C4 contribution to the ecosystem respiration (f4R) increased from June to September, and then became constant at 63–67% through October and November. The seasonal variation in f4R reflected the biomass composition of C3 and C4 plants at the measurement site. The seasonal C4 contribution to photosynthesis (f4P) was significantly different from its contribution to f4R in May (8%) while it showed similar values to f4R after June. The seasonal variations in f4R and f4P reflect the biomass composition ratio. Such seasonal transition from C3 to C4 of relative contribution to the carbon flux is similar to that observed in humid prairie ecosystems, while it is different from that in dry prairie ecosystems where the contribution of C3 plants is lower and the seasonal maximum of the C4-plant contribution occurs earlier compared to the humid prairie ecosystems. 相似文献
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Cytological characteristics of microconidia of <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis>
Izumi Chuma Takeshi Shinogi Naoki Hosogi Ken-ichi Ikeda Hitoshi Nakayashiki Pyoyun Park Yukio Tosa 《Journal of General Plant Pathology》2009,75(5):353-358
The inner cellular structure of microconidia of Magnaporthe oryzae was examined using fluorescent probes and electron microscopic techniques. The volume of the nucleus relative to the cell
was significantly larger in microconidia than in macroconidia or vegetative hyphae, similar to observations for spermatia
of other fungi. Selective fluorescent staining revealed that cytosolic RNA was less abundant in microconidia than in macroconidia
and germ tubes, suggesting that general metabolic activity in microconidia is low. Consistently, GFP expression driven by
the TrpC promoter was highly active during the formation of phialides and microconidia but gradually decreased as the microconidia
matured. Such data suggest that microconidia are in a quiescent or dormant state. 相似文献
10.
Hayama Yoko Yanase Tohru Suzuki Moemi Unten Kazuhiko Tomochi Hisayuki Kakehi Mayu Shono Yukina Yamamoto Takehisa Kobayashi Sota Murai Kiyokazu Tsutsui Toshiyuki 《Tropical animal health and production》2018,50(1):209-215
Tropical Animal Health and Production - Akabane virus, the pathogen-causing Akabane disease, is an arthropod-borne virus (arbovirus) transmitted by the Culicoides biting midge. A nationwide... 相似文献