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61.
A simple and rapid analytical method for strigolactones, germination stimulants for the root parasitic weeds witchweed (Striga spp.) and broomrape (Orobanche spp.), has been developed using high-performance liquid chromatography connected to tandem mass spectrometry (LC/MS/MS). The natural strigolactones (strigol, sorgolactone, orobanchol, and alectrol) were clearly separated and identified by LC/MS/MS. As low as 0.1 pg/microL of strigol and 0.5 pg/microL of sorgolactone could be quantified, whereas 1 pg/microL was needed for the quantification of orobanchol (S/N > 10). Using this method, it was found that red clover produces orobanchol and alectrol but not strigol. The roots of red clover seedlings were found to produce 13, 70, 58, and 65 pg of orobanchol/plant 1, 2, 3, and 4 weeks after germination, respectively.  相似文献   
62.
Supercritical carbon dioxide extraction of turmeric (Curcuma longa)   总被引:7,自引:0,他引:7  
Turmeric oil was extracted from turmeric (Curcuma longa) with supercritical carbon dioxide in a semicontinuous-flow extractor. Extraction rate was measured as a function of pressure, temperature, flow rate, and particle size. The extraction rate increased with an increase in CO(2) flow rate and with a reduction of particle size. The effect of pressure and temperature on turmeric extraction suggested the use of higher pressure and lower temperature at which solvent density is greater and thus the solubility of the oil in the solvent is greater in the range of 313-333 K and 20-40 MPa. The major components ( approximately 60%) of the extracted oil were identified as turmerone and ar-turmerone by GC-MS.  相似文献   
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Sequential isolation of rotavirus from individual calves   总被引:1,自引:0,他引:1  
An outbreak of neonatal calf diarrhea was studied on a breeding farm of Japanese indigenous beef cattle. During the breeding season of 1982, 43 calves were born over the period 27 February-28 April. All but one of the calves suffered from neonatal diarrhea and 5 died. Bovine rotavirus was isolated in cell cultures from fecal specimens of 39 (90.7%) of the 43 calves during the outbreak, strongly suggesting that this was the causative agent; the virus was readily isolated from 81 (83.5%) of 97 specimens of diarrhea. Rotavirus was subsequently isolated from the feces of 7 of the calves in early May, more than one month after the initial virus isolation in early March. Two of these calves were again rotavirus-positive in early June, 41 days after the second virus isolation. Diarrhea had ceased in all 7 calves in March. Some antigenic differences were shown by the neutralization test between the early and later isolates from one of these calves, suggesting either re-infection with a serologically different virus, or persistent infection with the original virus following antigenic modulation.  相似文献   
65.
Coding assignments of genome segments 1 and 2 of Chuzan virus strain K-47 were studied in vitro by using rabbit reticulocyte lysates. The double-stranded RNA segment was extracted from sodium dodecyl sulfate (SDS)-polyacrylamide gels by a modified crushing and eluting technique. Translation products labeled with [35S]methionine were resolved by SDS-polyacrylamide gel electrophoresis. The molecular weights of the products from RNA segments 1 and 2 were estimated to be 98 and 95 kilodaltons, respectively.  相似文献   
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