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教学活动的设计和使用成为英语课堂一个十分重要的环节,对最终的教学效果起不可或缺的作用.本文试从英语课堂教学活动的设计和活动方法两个方面,从教师的角度对该问题进行了初步探讨,对英语教师的课堂活动设计有一定参考作用. 相似文献
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新入侵害虫螺旋粉虱的田间药效试验及防效 总被引:8,自引:4,他引:8
螺旋粉虱(Aleurodicus disperses Russell)是新入侵我国海南省的l种外来有害生物,对农业生产和生态环境具有较大危害性.田间防治研究结果表明:10%(质量分数,以下各农药浓度均为质量分数)联苯菊酯乳油、10%高效灭百可乳油、4.5%高效氯氰菊酯乳油等3种菊酯类杀虫剂对螺旋粉虱均表现出良好的速效性和持效性,其中又以10%高效灭百可乳油防效最高,为98.32%~100%;40%乐果乳油、30%敌百虫乳油和40%乙酰甲胺磷乳油等3种有机磷类农药的防效以40%乙酰甲胺磷乳油较好,但都低于上述3种菊酯类农药的防效;98%巴丹粉剂速效性较好,持效性较低;18%杀虫双水剂的速效性和持效性均较差. 相似文献
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Ogawa K Sakakibara H Iwata R Ishii T Sato T Goda T Shimoi K Kumazawa S 《Journal of agricultural and food chemistry》2008,56(12):4457-4462
The anthocyanin composition and antioxidant activity of the crowberry ( Empetrum nigrum) were studied. High-performance liquid chromatography (HPLC) combined with a diode array detector and electrospray ionization mass spectrometry were used for identification and quantification of individual anthocyanins. Freeze-dried crowberry powder was extracted with 80% methanol containing 0.5% acetic acid and subjected to HPLC. Thirteen kinds of anthocyanins were identified. The major anthocyanins were cyanidin-3-galactoside and delphinidin-3-galactoside, at 8.04 and 8.62 mg/g extract, respectively. The HPLC profile of crowberry extract was similar to bilberry and blueberry. The total content of anthocyanins in crowberry was 41.8 mg/g extract, higher than the other nine major berry species (2.5-38.8 mg/g extract). The antioxidant activity was also evaluated using the 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis(3-ethybenzothiazoline-6-sulfonic acid) radical quenching assays and the ferric reducing activity power assy. Crowberry extract exerted the strongest antioxidant activity. In conclusion, individual anthocyanins in crowberry were identified and then quantified in this study. Additionally, crowberry is suggested to be associated with a reduction in the risk of developing chronic diseases because of its strong antioxidant activity. 相似文献
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HIDEHIRO INAGAKI YOSHIKI ISHIDA AKIRA UCHINO KIMIHIKO KATO CHIZUKO KAGEYAMA HIROYUKI IYOZUMI HIDEKI NUKUI 《Weed Biology and Management》2008,8(2):78-84
We examined the ultraweak photon emissions from a paddy weed, Scirpus juncoides , to assess the availability of photon emissions for the identification of weed biotypes resistant to sulfonylurea herbicides. The emission intensity from the plant organs increased when treated with a sulfonylurea herbicide in a concentration-dependent manner. The increment in emissions was higher in the sulfonylurea-resistant biotypes than in the sulfonylurea-susceptible biotypes. The difference between the biotypes was greater in the culms than in the roots and remained so through the vegetative growth stage to the flowering stage. This difference was independent of the seed source or mutations in the acetolactate synthase genes of the resistant biotypes. These results suggest that the determination of ultraweak photon emissions can be a useful method for identifying the sulfonylurea-resistant biotypes of S. juncoides. 相似文献
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Shyamal C MAHATA Ryoichi MITSUO Jun-Ya AOKI Hironori KATO Takao ITAKURA 《Fisheries Science》2003,69(3):615-624
ABSTRACT: The cytochrome P450 (CYP) represents a large group of microsomal monooxygenases that catalyze drugs as well as a host of lethal environmental contaminants such as dioxins, leading to either detoxification and excretion from the animal or generation of carcinogenic intermediates. In the present study two forms of cDNA were cloned (Eu MC1 and Eu MC2) for European eel CYP1A genes by polymerase chain reaction (PCR) techniques. The cDNA of Eu MC1 was 3368 bp long coding 521 amino acid residues, and that of Eu MC2 was 2464 bp long coding 517 amino acid residues. Identities of deduced amino acid sequences between Eu MC1 and Japanese eel CYP1A1 and that between Eu MC2 and the second form of Japanese eel CYP1A were 98% and 97%, respectively, showing decisively that Eu MC1 and Eu MC2 are orthologous to Japanese eel CYP1A1 and the second form of CYP1A, respectively. A striking difference between the two eel species was that the Eu MC1 peptide was two amino acid residues longer than that of the Japanese eel CYP1A1. Existence of two loci of CYP1A in Japanese and European eels may suggest that the two forms of CYP1A exist widely among the eel species, because the divergence between the two eel species has been shown to be close to the basal divergence among eels. The identities in CYP1A may help to estimate genetic distance between European and Japanese eels. 相似文献
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Yoshinori MATSUDA Hideyoshi TOYODA Yasunari KATO Koji KAKUTANI Takayuki NAKANISHI Miki BINGO Teruo NONOMURA Seiji OUCHI 《Journal of General Plant Pathology》2000,66(1):59-63
A nonpathogenic mutant of Ralstonia solanacearum was produced by the insertion of transposon Tn4431. The mutagenized gene was then cloned from a genomic DNA library by the
gene tagging method, using the labeled lux operon located on Tn4431 of pUCD623 as a hybridization probe. From nucleotide sequence analysis of the transposon-inserted
genomic clone, the hrpB gene was shown to be disrupted by the inserted transposon. Tomato plants were inoculated with the hrpB-disrupted mutant bacteria, for which multiplication and translocation were then monitored using the colony hybridization
method. In addition, the original pathogenic bacteria in which the lux operon had been functionally ligated with the genomic promoter were also used for inoculation and traced by their bioluminescence.
Multiplication of the hrpB-disrupted mutant was suppressed initially in the invaded root tissues and then in upper hypocotyl after translocation, suggesting
that the pathogenic strain of R. solanacearum overcomes at least two steps of host responses expressed in root and hypocotyl tissues. Thus, our approach for molecular
monitoring of the bacteria enabled us to precisely analyze the infection behavior of the pathogenic bacteria in planta.
Received 16 April 1999/ Accepted in revised form 10 August 1999 相似文献