Specific detection of potentially allergenic peach and apple in foods using polymerase chain reaction

Two PCR methods were developed for specific detection of the trnS-trnG intergenic spacer region of Prunus persica (peach) and the internal transcribed spacer region of Malus domestica (apple). The peach PCR amplified a target-size product from the DNA of 6 P. persica cultivars including 2 nectarine and 1 flat peach cultivar, but not from those of 36 nontarget species including 6 Prunus and 5 other Rosaceae species. The apple PCR amplified a target-size product from the DNA of 5 M. domestica cultivars, but not from those of 41 nontarget species including 7 Maloideae and 9 other Rosaceae species. Both methods detected the target DNA from strawberry jam and cookies spiked with peach and apple at a level equivalent to about 10 μg of total soluble proteins of peach or apple per gram of incurred food. The specificity and sensitivity were considered to be sufficient for the detection of trace amounts of peach or apple contamination in processed foods.     

Occurrence of glucosamine in higher plants

Occurrence of the unknown basic ninhydrin positive substance in young plant tissue supplied with a high level of ammonium nitrogen has been reported in the previous paper (1). This substance disappeared when the supply of ammonium nitrogen was stopped or the source of nitrogen was changed from ammonium nitrogen to nitrace nitrogen, and this substance was verg scarcely detected when the level of ammonium nitrogen in culture solution was as low as 3 ppm or the foren of nitrogen source was nitrace nitrogen. It is very interesting to identify this substance, as the occurrence of this substance is a distinctive character of the plant which han been supplied with a higher level of ammonium nitrogen and has developed the symptoms of ammonia toxicity.     

Responses to aluminium of suspension-cultured tobacco cells in a simple calcium solution

In a simple solution containing 3 mM CaCl₂ and 3% sucrose (pH 4.5), tobacco cells (Nicotiana tabacum L.) at the logarithmic phase of growth remained viable at least for 24 h. In this medium, the toxic effect of aluminium (Al) on the plasma membrane was investigated for up to 24 h. After the addition of Al to the cell suspension, Al started to accumulate immediately in the cells, and a maximum value was observed at 9 h. Al induced callose deposition, but did not enhance significantly the uptake of Evans blue (a nonpermeating dye), the per oxidation of lipids and the leakage of potassium (K) ions. Furthermore, the AI-treated cells were stained with fluorescein diacetate (FDA) as much as untreated control cells. These results suggest that the accumulation of Al does not damage the membrane. The addition of Fe(II) to the cells which had been exposed to Al for 12 h resulted in immediate lipid peroxidation and Evans blue uptake several hours later. A combination of Al and Fe(II) caused the K leakage, and enhanced the deposition of callose more than Al alone. These results suggest that the accumulation of Al sensitizes the membrane to the Fe(II)-mediated peroxidation of lipids, and that the Al-enhanced per oxidation of lipids is a direct cause of the loss of integrity of the plasma membrane (or cell death) in the Ca medium.     

Uptake of 15 trace elements in arbuscular mycorrhizal marigold: Measured by the multitracer technique

The effect of arbuscular mycorrhizal (AM) colonization on the uptake of trace elements in marigold (Tagetes patula L.) was studied using a multitracer consisting of radionuclides of ⁷Be, ²²Na, ⁴⁶Sc, ⁵¹Cr, ⁵⁴Mn, ⁵⁹Fe, ⁵⁶Co, ⁶⁵Zn, ⁷⁴As, ⁷⁵Se, ⁸³Rb, ⁸⁵Sr, ⁸⁸Y, ⁸⁸Zr, and ^95mTc. Marigold plants were grown under controlled environmental conditions in sand culture either without mycorrhizas or in association with an AM fungus, Glomus etunicatum. The multitracer was applied to the pot, and plants were harvested at 7 and 21 d after tracer application. We found that the uptake of ⁷Be, ²²Na, ⁵¹Cr, ⁵⁹Fe, ⁶⁵Zn, and ^95mTc was higher in the mycorrhizal marigolds than in the non-mycorrhizal ones, while that of ⁴⁶Sc, ⁵⁶Co, ⁸³Rb, and ⁸⁵Sr was lower in the mycorrhizal marigolds than in the non-mycorrhizal ones. Thus, the multitracer technique enabled to analyze the uptake of various elements by plant simultaneously. It is suggested that this technique could be used to analyze the effects of AM colonization on the uptake of trace elements by plant.     

Response of determinate- and semi-determinate-types of common bean to elevated CO2 concentration in the atmosphere

The growth of determinate-type and semi-determinate -type plants of common beam (Phaseolus vulgaris L.) was studied at elevated (700 μL L^-1) and ambient (350 μL L^p-1) CO, concentrations in an open-top chamber. Successive changes in dry matter production and in the number of stems and branches were investigated. To evaluate the sink-source balance at different CO₂ concentrations, ¹³CO₂ was introduced to the leaves during the pod filling stage and the ¹³C distribution profile was analyzed. In the elevated CO₂ treatment, no significant differences in dry matter production were observed for the determinate -type plants, unlike in the semi-determinate-type ones, where the volume was 1.3 times bigger than those in the ambient CO₂ treatment. This enhanced growth in the semi-determinatetype plants mainly involved the branches. Starch accumulation in leaves at elevated CO₂ concentratton was up to 200 and 300 mg glucose g DML^-1 for determinate- and semi-determinate-types, respectively. Though the increased accumulation of starch under elevated CO₂ treatment was more pronounced in the semi-determinate-type plants, it appeared that photosynthesis was not down-regulated. The net assimilation rate of the semi-determinate-type plants in the elevated CO₂ treatment was generally higher than that in the ambient CO₂ treatment. The semi-determinate-type plants could take advantage of the elevated CO₂ treatment for the distribution of photosynthates to branches, while in the determinate-type plants the growth of the branches could not be expanded, and consequently plant growth was not enhanced by elevated CO₂ treatment.     

Arbuscular mycorrhizal fungal communities associated with some pioneer plants in the lahar area of Mt. Pinatubo,Philippines

An extensive area has been buried due to the repeated occurrence of mud flows (lahars) derived from volcanic deposits during the eruption of Mt. Pinatubo in the Philippines. Most of the area was covered with sparse vegetation consisting of only a few gramineous pioneer plants such as Saccharum spontaneum (site SV). However dense vegetation consisting of wild leguminous plants such as Calpogonium mucunoides showed a patch distribution (site DV). In 1999, we investigated the community composition of AMF at these two sites. S. spontaneum at both sites was slightly colonized with AMF while the leguminous plants were highly colonized. Spores of AMF were collected from the rhizosphere of these plants. Eight spore morphotypes were identified; one each for Acaulospora and Entrophospora colombiana, two for Glomus, one for Paraglomus, and three for Scutellospora. Part of the 18S rRNA gene of AMF colonizing the plant roots was amplified with AMF-specific primers, NS31 and AM1, cloned and sequenced. Fifty-three AMF clones were phylogenetically classified into 8 phylotypes as follows: one each for Acaulospora and E. colombiana, five for Glomus, and one for Scutellospora. Both molecular and morphological examinations showed that the diversity of AMF was comparable to that in other temperate ecosystems with abundant vegetation and did not differ significantly between sites SV and DV, regardless of the vegetation cover. Furthermore, S. spontaneum supported diverse AMF species in spite of its scant growth at site SV. E. colombiana was mostly associated with C. mucunoides. Significance of AMF for the primary plant succession in the lahar area was analyzed.     

Exchangeable Cs/K ratio in soil is an index to estimate accumulation of radioactive and stable Cs in rice plant

Pot and field experiments were conducted to clarify the effect of soil exchangeable potassium (K) and cesium-137 (¹³⁷Cs) on ¹³⁷Cs accumulation and to establish soil index in rice (Oryza sativa L.). Four paddy soils in Fukushima Prefecture, Japan, showing different transfer factors for radioactive Cs derived from the accident of Fukushima Daiichi Nuclear Power Station in the field were compared in terms of ¹³⁷Cs accumulation in rice in a pot experiment. ¹³⁷Cs accumulation in shoots and brown rice widely varied among soils with the transfer factor ranging from 0.018 to 0.068 for shoots and 0.004 to 0.065 for brown rice. ¹³⁷Cs concentration in brown rice and shoots tended to decrease with higher levels of soil exchangeable K, and they were more closely related to the exchangeable Cs/K ratio. Similar relationships between the Cs/K ratio and Cs accumulation in plants were obtained for the stable isotope cesium-133 (¹³³Cs). The distributions of ¹³⁷Cs and ¹³³Cs in grains were also similar and variable among soils. The transfer factors obtained in pot experiments mostly agreed with field observations. The results imply that the exchangeable ¹³⁷Cs/K can be a potential soil index to estimate ¹³⁷Cs accumulation in rice.     

Evaluation of water resources by snow storage using water balance and tank model method in the Tedori River basin of Japan

We evaluate water resources as the difference between the observed and virtual discharges, defined as discharge without snow storage during the snowfall and snowmelt season, in the Tedori River basin of Ishikawa Prefecture, Japan. The virtual discharge was estimated using the Tank model, in which parameters of calculated discharge were determined when the predictions were consistent with the observed discharges except for those during snowfall and snowmelt periods. Precipitation increase factors, i.e., the ratio of precipitation in the basin to that of a Kanazawa site, ranged from 1.46 to 2.00 with an average of 1.68. Water resources by snow storage (WRSS) during 31 years from July 1976 to June 2006 were estimated to be 400–1,500 mm in depth, which could be considered a significant amount. WRSS gradually decreased over time from 1976 to 2006. We propose the water balance method to estimate WRSS and water resources by snowmelt (WRSM), which easily estimates these parameters without the need for any detailed analysis of hydrograph as that of the Tank model. If snowfall decreases due to global warming, we suggest this area would suffer an irrigation water shortage under the water right, especially in the early spring.     

Effect of imidacloprid and fipronil pesticide application on Sympetrum infuscatum (Libellulidae: Odonata) larvae and adults

The effect of imidacloprid and fipronil on Sympetrum infuscatum larvae and adults during the rice cultivation period was monitored using an experimental micro-paddy lysimeter (MPL) system. Twenty-two hatched larvae were laid on the soil surface of each MPL. MPLs were treated with imidacloprid, fipronil, and the control MPL was left untreated. The pesticide concentration, S. infuscatum larval and adult populations, and larval emergence time were monitored in each MPL. The maximum imidacloprid and fipronil concentration in paddy water was 52.8 μg/l at 1 day, and 1.3 μg/l at 6 h, respectively, after the pesticide application. Both pesticides dissipated quickly in paddy water, with half-lives of 8.8 and 5.4 days for imidacloprid and fipronil, respectively. The absence of S. infuscatum larvae and exuviae in the fipronil-treated MPL was remarkable. The larval survival decreased to 63.6 ± 18.2, 15.2 ± 2.6, and 0% in the control, imidacloprid-treated, and fipronil-treated MPLs, respectively, by 9 days after pesticide application. Emergence in the imidacloprid-treated MPL was also significantly lower than that in the control MPL. The observed decrease in the abundances of S. infuscatum larvae and adults in MPLs seems to be both directly and indirectly associated with nursery-box application of fipronil and imidacloprid.     

Effect of synchronization of donor cells in early G1‐phase using shake‐off method on developmental potential of somatic cell nuclear transfer embryos in cattle

In this study, we compared the developmental ability of somatic cell nuclear transfer (SCNT) embryos reconstructed with three bovine somatic cells that had been synchronized in G0‐phase (G0‐SCNT group) or early G1‐phase (eG1‐SCNT group). Furthermore, we investigated the production efficiency of cloned offspring for NT embryos derived from these donor cells. The G0‐phase and eG1‐phase cells were synchronized, respectively, using serum starvation and antimitotic reagent treatment combined with shaking of the plate containing the cells (shake‐off method). The fusion rate in the G0‐SCNT groups (64.2 ± 1.8%) was significantly higher than that of eG1‐SCNT groups (39.2 ± 1.9%) (P < 0.05), but the developmental rates to the blastocyst stage of SCNT embryos per fused oocytes were similar for all groups. The overall production efficiency of the clone offspring in eG1‐SCNT groups (12.7%) per recipient cow was higher than that in G0‐SCNT groups (3%) (P < 0.05). The mean birth weight of cloned calves and the average calving score in the G0‐SCNT groups (48.1 ± 3.4 kg and 3.3 ± 0.3, respectively) was significantly higher (P < 0.05) than those of eG1‐SCNT groups (37.2 ± 2.1 kg and 2.3 ± 0.2, respectively). Results of this study indicate that synchronization of donor cells in eG1‐phase using the shake‐off method improved the overall production efficiency of the clone offspring per transferred embryo.