Molecular detection of Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' Infection in cats by direct PCR using whole blood without DNA extraction

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.     

Seasonal contribution of C3 and C4 species to ecosystem respiration and photosynthesis estimated from isotopic measurements of atmospheric CO2 at a grassland in Japan

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 (f_4R) increased from June to September, and then became constant at 63–67% through October and November. The seasonal variation in f_4R reflected the biomass composition of C₃ and C₄ plants at the measurement site. The seasonal C₄ contribution to photosynthesis (f_4P) was significantly different from its contribution to f_4R in May (8%) while it showed similar values to f_4R after June. The seasonal variations in f_4R and f_4P 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.     

Evaluation of bovine spongiform encephalopathy (BSE) infection risk of cattle via sewage sludge from wastewater treatment facilities in slaughterhouses in Japan

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.     

Acquisition of quinolone resistance and point mutation of the gyrA gene in Campylobacter jejuni isolated from broilers and in vitro-induced resistant strains

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.     

Use of soil nonexchangeable potassium by paddy rice with clay structural changes under long-term fertilizer management

To prove the hypothesis that paddy rice utilizes soil nonexchangeable potassium (neK) and causes associated structural changes in clay minerals, K status and clay mineralogy of 22 surface soils from three paddy fields under long-term fertilizer management for 51–93 years were investigated. Soil neK content was determined as the difference between 1 mol L⁻¹ hot HNO₃ extractable K and 1 mol L⁻¹ ammonium acetate exchangeable K. Clay mineralogy was identified by X-ray diffraction (XRD). The radiocesium interception potential (RIP), an index of frayed edge sites in the interlayer sites of 2:1 type clay minerals, was also determined. The neK contents under the -K and NPK treatments were considerably lower than those under the unfertilized treatment in all the fields, indicating the exploitation of soil neK by rice. XRD analysis of the clay samples revealed 7% shift from the 1.0 peak to 1.4 nm one under the -K treatment compared with the unfertilized one, and the amounts of neK were negatively correlated with those of RIP (p < .01), suggesting the expansion of interlayer spaces of the 2:1 type phyllosilicates such as mica due to the release of neK. In addition, the neK content positively correlated with K balance of the long-term experiments (p < .05). The differences of neK between unfertilized K and -K treatments corresponded to 22–157 kg K ha⁻¹, or 0.42–1.68 kg K ha⁻¹ year⁻¹. In conclusion, utilization of considerable amount of soil neK under K depleted conditions should be considered to establish sustainable K management for paddy rice.     

Development and evaluation of an enzyme-linked immunosorbent assay based on recombinant TgSRS2 for serodiagnosis of Toxoplasma gondii infection in cats

An enzyme-linked immunosorbent assay (ELISA) based on recombinant SAG1-related sequence 2 of Toxoplasma gondii (rTgSRS2) was developed to detect toxoplasmosis in cats. The specificity and sensitivity of rTgSRS2 ELISA were confirmed using a series of serum samples from T. gondii-experimentally infected mice. A total of 76 field samples from cats were examined by the developed ELISA. The rTgSRS2 ELISA showed a good diagnostic performance characterized by high concordance (88.16) and kappa value (0.76) with latex agglutination test (LAT). The sensitivity and specificity of the test were 92.68% and 82.86%, respectively. These results suggest that the ELISA based on rTgSRS2 could be a useful tool for serodiagnosis of T. gondii infection in cats.     

Modeling the effects of N application on growth,yield and plant properties associated with the occurrence of chalky grains of rice

The objective of this study was to propose a model for explaining rice responses to a wide range of N application rates in various growth attributes associated with the occurrence of chalky grains. We improved the sub-model for N uptake process of a previous rice model which was originally developed for explaining genotypic and environmental variations in the whole growth processes, considering the difference in the rate of N loss from the plant-soil system between indigenously supplied soil mineral N and fertilizer N. A total of 80 growth datasets of cultivar ‘Koshihikari’ grown at Shiga prefecture, Japan, in 2010 was utilized for the calibration and validation of the model. The rice growth model well explained the above-ground biomass growth (RMSD = 78.7 g m^?2) and rough dry grain yield (RMSD = 83.2 g m^?2) for the validation data-set, simultaneously. The simulated carbohydrate content available per single spikelet was negatively correlated with the observed percentage of the milky-white grain which includes white-cored grain (r = ?.77, p < .001) for all the data-sets of calibration and validation. On the other hand, the observed percentage of the sum of white-back and white-base grains was closely correlated with the simulated plant N content available per single spikelet (r = ?.59, p < .001). It was suggested that the present rice growth model would rationally explain the effects of N application on the occurrence of the chalky grains through the dynamic change of the carbohydrate content and plant N content available per single spikelet.     

Meteorological factors affecting seroconversion of Akabane disease in sentinel calves in the subtropical Okinawa Islands of Japan

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...     

Effect of activation treatments on actin filament distribution and in vitro development of miniature pig somatic cell nuclear transfer embryos

In the present study, we investigated the effect of activation treatments on the actin filament distribution and in vitro development of somatic cell nuclear transfer (SCNT) embryos in miniature pigs. We combined three activation methods, ionomycin (ION), electrical stimulation (ES), and cycloheximide treatment (CH), to prepare seven activation treatments (ION, ES, CH, ION + CH, ION + ES, ES + CH and ION + ES + CH). First, we investigated the activation rate of oocytes and in vitro development of parthenotes. The activation rates of the oocytes in the ION, ES, CH, ION + CH, ION + ES, ES + CH, and ION + ES + CH groups were 42.9, 51.3, 0.0, 82.1, 80.6, 78.1 and 78.6%, respectively, showing that the rates of the combined treatment groups were significantly higher (P<0.05) than those of the single treatment groups. Although there were no significant differences in the activation rates of the combined treatment groups, the developmental rate to blastocysts in the ION + CH treatment group (36.1%) was significantly higher (P<0.05) than the other combined treatment groups (14.6-24.7%). Subsequently, we investigated the in vitro development and distribution of microfilaments in SCNT embryos. The developmental rate to blastcysts of the SCNT embryos in the ION + CH treatment group (11.3%) was significantly higher (P<0.05) than in the ES and ION + ES + CH treatment groups (4.5 and 5.2%, respectively). The rate of normal actin filament distribution in the SCNT embryos activated with ION + CH was significantly higher (P<0.05) than those activated with ES or ION + ES + CH treatment (63.3 vs. 46.8 or 46.4%). In addition, the fragmentation rate of the SCNT embryos activated with ION + CH was significantly lower (P<0.05) than those activated with ION + ES + CH (14.9 vs. 26.1%). The present results suggest that an activation treatment of ionomycin combined with cycloheximide may avoid physical damage to microfilaments and result in improved subsequent development of miniature pig SCNT embryos.