共查询到20条相似文献，搜索用时 31 毫秒
1.
Significant alterations in serum protein of mice following Hymenolepis nana infection were observed. These changes were recorded as decrease in albumin, increase in gamma globulin and a temporary rise in alpha-1, alpha-2 and beta globulins. The decrease in albumin and increase in gamma globulin occurred as early as on 1st day after infection. The alpha-1 and alpha-2 globulins did not show definite profile during infection. The beta globulin predominantly increased till the day 20 post infection and thereafter generally decreased. Repeated infection did not enhance any further alterations in serum protein. There was no significant correlation between infection dose levels and serum protein changes. 相似文献
2.
Management of Cercospora leaf spot of groundnut (Arachis hypogaea L.) with a single fungicidal spray
Field trials were conducted during the rainy seasons of 1993/94 for chemical control of groundnut leaf spot using a single spray. A fungicide mixture ofcarbendazim 0.05%+mancozeb 0.2% was applied once in different treatments. Spray timings varied from 30 d.a.s. to 80 d.a.s. at 10-day intervals. Spray application reduced the percent disease index in all treatments. A statistically significant increase in pod yield was obtained in treatments sprayed up to 50 d.a.s. in 1993. The yield data were not significantly different in 1994. Sprays at 40 d.a.s. in 1993 and 50 d.a.s. in 1994 gave maximum returns. The cost of treatmentdid notvary significantly. The benefitto cost ratio oftreatments ranged from 1.1 to 8.1 in 1993 and 4.1 to 5.5 in 1994. 相似文献
3.
For the first time with a rust fungus, continuously growing axenic cultures have been obtained from single spores. This was achieved with aeciospore sources of the pine stem rust Peridermium pini (Pers.) Lev. from Thetford Forest, East Anglia, but not with sources from north-east Scotland. Approximately 30% of the single spores of two East Anglian sources out of the three tested developed into transferable and subculturable colonies on modified Harvey & Grasham's medium. 相似文献
4.
5.
6.
7.
单条线虫DNA提取方法 总被引：8，自引：0，他引：8
大量线虫DNA的提取可能因线虫不纯而受到污染,溶液多次转移造成DNA损失,并且在提取过程中加入过多的溶质离子也可能对PCR扩增有干扰,从而影响下一步的研究。本研究用液氮快速冷冻单条线虫,继以85℃快速变温,用温度的剧烈变化使线虫裂解,再以蛋白酶K降解蛋白质,提高了获得的DNA的纯度和数量。通过多种线虫的验证试验表明,该方法高效、快速、稳定。该试验方法有如下优点:(1)使用Taq酶附带的PCR Buffer代替WLB裂解液和SDS裂解液,减少了配置的不确定性和外来离子的影响。(2)整个提取过程在一个PCR管中完成,并可直接用于PCR扩增,没有溶液的转移和过多的溶质添加,减少污染和对后续PCR的影响。(3)使用变温处理代替其他手工破碎方法,减少了外界污染物的掺入,不需要手工操作技巧。与另外2种提取线虫DNA的蛋白酶K方法相比,本研究提取单条线虫DNA的时间短,效率高,PCR扩增结果稳定可靠,符合快速检测的需求;此外,本研究所使用的方法降解单条线虫蛋白质彻底,提取DNA数量多,稀释32倍仍能扩增出明显的条带,可进行多次分子试验研究。 相似文献
8.
Malandrakis Anastasios A. Apostolidou Zoi A. Markoglou Anastasios Flouri Fotini 《European journal of plant pathology / European Foundation for Plant Pathology》2015,142(3):489-499
European Journal of Plant Pathology - 42 field isolates of Alternaria alternata collected from infected tomato fruit of processing plants located in the region of Pelloponisos, South Greece, were... 相似文献
9.
手工挑取真菌单孢子显微操作技巧 总被引：4，自引：2，他引：2
介绍了采用简易挑孢针在普通显微镜下,手工直接挑取琼脂培养基表面上的真菌孢子的操作技巧。虽然有一定的操作难度、技巧性强,但具有工具简单、分离效率高以及可满足特殊操作需要等独特优点。 相似文献
10.
ABSTRACT The effect of mixed cropping on disease suppressiveness of soils was tested for two cropping systems, Brussels sprouts-barley and triticale-white clover. Disease suppressiveness of field soils was evaluated in bioassays for the soilborne pathogens Rhizoctonia solani, Fusarium oxysporum f. sp. lini, and Gaeumannomyces graminis var. tritici. For both cropping systems, mixed cropping did not enhance disease suppressiveness of the soils. In some cases, soil cropped to barley alone was significantly more suppressive to F. oxysporum f. sp. lini than soils cropped to Brussels sprouts or the mixture of Brussels sprouts and barley. Analyses of the diversity of the indigenous bacterial and fungal microflora by denaturing gradient gel electrophoresis of amplified 16S- and 18S-rDNA fragments, respectively, revealed, in most cases, no significant differences between mixed and mono-cropped soils. In conclusion, in this study, mixed cropping of soils with Brussels sprouts and barley or with triticale and white clover did not enhance microbial diversity or disease suppressiveness of soils to three different soilborne plant pathogens. 相似文献
11.
WanXue Bao Takuya Nagasaka Shin Inagaki Sho Tatebayashi Iori Imazaki Shin-ichi Fuji Takashi Tsuge Masafumi Shimizu Koji Kageyama Haruhisa Suga 《Plant pathology》2020,69(5):901-910
Fusarium fujikuroi, the causative agent of bakanae disease in rice, produces many kinds of secondary metabolites. Recently, two phylogenetic subgroups (F and G groups) of Japanese F. fujikuroi have been identified and found to have differences in their gibberellin (GA) and fumonisin production. G-group F. fujikuroi produces large amounts of GA, but is a fumonisin nonproducer. F-group produces large amounts of fumonisin, but is a GA low or nonproducer. We investigated the cause of low GA production in the F-group. Genetic mapping suggests that low GA production in the F-group strain Gfc0825009 is due to a GA gene cluster for GA biosynthesis. Analysis of the nucleotide and amino acid sequences of the genes in the GA gene cluster showed >98.4% homology between the F-group strain Gfc0825009 and the G-group strain Gfc0801001. Following a 7-day culture under low nitrogen conditions, we found that expression of P450-1, P450-4, and P450-2 in the cluster increased in the G-group strain and not in the F-group strain. We hypothesized that complementation by GA genes in the G-group strain would be required to increase GA production in the F-group strain. However, we found that this occurred with a single gene complementation of DES, P450-1, P450-4, or P450-2. Simultaneous increase in the expression of P450-1, P450-4, and P450-2 were detected in the complementary transformants. Moreover, the same phenomenon was observed by reintegration of its own P450-1. Our results suggest the presence of unknown regulatory mechanisms of the GA gene cluster in F. fujikuroi. 相似文献
12.
Soil solarization (SoSol) with a single layer of transparent polyethylene (PE) film, traps considerable heat and moisture in soil. Solarization of field soil with two layers of 1 mil (25 μm thick) PE film, separated by a 6-cm air layer, caused soil temperatures at 15 cm depth to rise by 12.7°C and 3.6°C over those in noncovered soil or soil covered by one layer of film, respectively; at 30 cm depth the respective differences in temperature were 11.2°C and 2.7°C. Viability of propagules (mainly chlamydospores) ofFusarium oxysporum f. sp.vasinfectum that had been buried at 30 cm depth, was reduced after 31 days of solarization by 97.5%, 58%, and 0% under a double film layer, a single layer, and in non-covered soil, respectively. The insulating effect of a double layer of PE film improved heat retention in soil and the solarization effect. 相似文献
13.
剪股颖粒线虫(Anguina agrostis)是牧草、草坪上的重要线虫,该线虫在进口草籽中常以幼虫形态出现,与其它粒线虫属幼虫形态相似,很难快速鉴定到种.本实验通过对单条幼虫DNA进行提取和PCR扩增,获得其rDNA的ITS区域,测序后与基因库中的剪股颖粒线虫的rDNA的ITS区域序列进行比较,其结果与基因库中编码为AF396343.1的核酸序列吻合,从而鉴定为剪股颖粒线虫.此外,还使用5种限制性内切酶对PCR产物进行了酶切,获得了剪股颖粒线虫的ITS-RFLP指纹图谱. 相似文献
14.
膜孔灌溉条件下入渗规律的研究 总被引：10，自引：2，他引：10
对重粉质粘土进行了4种孔径的膜孔灌水及垂直一维入渗试验，观测了膜孔点源入渗过程中的累积入渗水量、水平湿润范围及速度、点源下渗速度等。结果表明，膜孔点源累积入渗水量符合考斯加可夫模型，并且得出了膜孔直径与入渗系数、入渗指数的关系。膜孔直径与湿润深度及膜孔直径与湿润半径间的关系。 相似文献
15.
芸薹根肿菌（Plasmodiophora brassicae）单孢分离接种及生理小种的鉴定 总被引：2，自引：0，他引：2
芸薹根肿菌(Plasmodiophora brassicae)单孢分离接种方法曾有报道,本试验改进了国外单孢分离技术.将休眠孢子悬浮液稀释到1个/0.5 μL,滴在一块消过毒的载玻片上,放置在显微镜下反复检查,以确保它精确只含有一个孢子.用微管将孢子吸入接种在2日龄白菜幼苗根毛上,营养液培养3周.为使其更接近田间发病环境条件,后期将疑似发病根在无菌土中继续进行病菌增繁.该方法能够有效地加快病菌繁殖感染,提高单孢分离接种成功率.对不同地区病菌进行大量单孢分离接种.本试验对3个地区的病菌单孢接种共950株,接种成功27株,使用Williams根肿病菌鉴别寄主鉴定,共9个生理小种. 相似文献
16.
ABSTRACT Tobacco cultivar Virgin A Mutant (VAM) is reported to have the recessive potyvirus resistance gene va. Varied levels of resistance were observed in VAM plants inoculated with Japanese potato virus Y (PVY) isolates. VAM was highly resistant to most of the PVY isolates tested and tolerant to three necrotic strain isolates of PVY-T. Based on data obtained from tissue printing and press blotting, the resistance appeared to be mainly at the level of cell-to-cell movement. PVY replicated in VAM proto-plasts, but the replication was 30% lower than in susceptible tobacco, suggesting that impairment of replication also contributes to resistance. To identify the viral gene product or products involved in VAM resistance, we isolated spontaneous resistance-breaking mutants by passing vein-banding (O strain) isolates several times through VAM plants. By comparing the amino acid sequences of the mutants with their original isolates, we identified a single amino acid substitution in the viral genome-associated protein (VPg) domain that is correlated with VAM resistance breaking. Together, these results suggest that, in addition to its role in replication, VPg plays an important role in the cell-to-cell movement of PVY. 相似文献
17.
Experimental infection of rainbow trout Oncorhynchus mykiss (Walbaum) with the monogenean Discocotyle sagittata (Leuckart, 1842) allowed comparison between trickle and single exposure, two infection modes demonstrated to occur in the wild. Both types of infection resulted in mean larval attachment success around 50%, which was significantly dependent on dose of infective larvae used (P < 0.0001), but was not affected by mode of infection (P = 0.244). Worms recovered from fish exposed to the same number of oncomiracidia but different mode of infection differed in their rate of development. The developmental stage attained by parasites was significantly affected by number of infective larvae used (P = 0.005), and by the interaction between dose and mode of infection (P = 0.026), suggesting competition among attached larvae. Statistical analysis demonstrated that in the early stages of infestation, worm distribution over the gill arches can be explained by the relative amount of water flowing over them. One, two and three months post-infection parasite numbers were comparable (P = 0.805), but their observed distribution gradually decreased in gill arches III and IV and increased in gill arch I, suggesting that parasites migrate after initial attachment. These results reproduce phenomena observed in the field, indicating that the experimental infection system could be employed to study infection dynamics and host-parasite interactions under controlled conditions. 相似文献
18.
Weng J Liu X Wang Z Wang J Zhang L Hao Z Xie C Li M Zhang D Bai L Liu C Zhang S Li X 《Phytopathology》2012,102(7):692-699
The major quantitative trait locus (QTL) qHS2.09 plays an important role in resistance to head smut during maize breeding and production. In this study, a near-isogenic line (NIL), L34, which harbors the major QTL qHS2.09 in bin 2.09, was developed using a resistant donor 'Mo17' in a susceptible genetic background 'Huangzao4'. Using 18,683 genome-wide polymorphic loci, this major QTL was finely mapped into an interval of ≈1.10 Mb, flanked by single nucleotide polymorphism (SNP) markers PZE-102187307 and PZE-102188421. Moreover, the favorable allele from 'Mo17' for SNP PZE-102187611 in this interval that was most significantly associated with resistance to head smut (P = 1.88 E-10) and accounted for 39.7 to 44.4% of the phenotypic variance in an association panel consisting of 80 inbred lines. With combined linkage and association mapping, this major QTL was finally located between SNP PZE-102187486 and PZE-102188421 with an interval of ≈1.00 Mb. Based on the pedigrees of 'Mo17' and its derivatives widely used in temperate maize breeding programs, the favorable haplotype from 'Mo17' is shown to be the main source of resistance to head smut in these lines. Therefore, the SNPs closely linked to the major QTL qHS2.09, detected in both linkage and association mapping, and could be useful for marker-assisted selection in maize breeding programs. 相似文献
19.
根据果树生理特性与土壤水动力学理论,建立了非恒定水位复杂边界条件下的蓄水单坑均质土入渗运动的数学模型,并采用交替方向隐式差分法进行求解。经试验验证,模拟结果与实测结果吻合较好,表明利用该方法模拟蓄水单坑的水分入渗问题是可行的。用本模型模拟了不同条件下的单坑入渗过程,根据模拟结果分析了不同因素对入渗规律的影响,为蓄水坑灌理论与灌水技术要素的深入研究奠定了基础。 相似文献
20.
小麦条锈病单片病叶特征光谱的初步研究 总被引：17，自引：0，他引：17
以健康小麦植株叶片为对照,把小麦条锈病病叶按照严重度分成8个级别,应用高光谱遥感(Hyperspectral Remote Sensing)技术,采用ASD Field-Spec Pro FR 2500型光谱仪和LI-Cor1800-12外置积分球,测定各级别单片病叶上发病区域的反射光谱。结果表明,随着病害严重度的增加,反射率随之增强。在350～1 600 nm波段范围内反射率与严重度基本成正相关,535 nm以后反射率与严重度相关达显著水平。选择相关性最高的波段(670～690 nm),利用SAS软件进行逐步回归分析,建立了小麦条锈病严重度和光谱反射率之间的回归模型,即y=-0.576 8+0.7953R685-0.603 6R690。 相似文献