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排序方式: 共有625条查询结果,搜索用时 15 毫秒
61.
O. Mendelsohn T. Dayan S. Aidlin‐Harari M. Silberstein V. Orlov L. Blank 《Journal of Applied Entomology》2018,142(4):371-379
The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is a major pest, infesting hundreds of crop types. Since current field monitoring is mostly manual, understanding the spatiotemporal patterns of pest emergence at the fine scale can optimize precise trap placement and site‐specific treatment activities, also within area wide integrated pest management projects. We carried out a three‐year study in deciduous orchards in Israel, testing for the existence of subplot hot spots in which medfly populations display small‐scale aggregations over consecutive seasons, beyond the expected spatial variability resulting from host type and ripening sequence. medfly population increase in these locations often preceded or was parallel to infestations in surrounding orchards, suggesting that hot spots can provide an important tool for effective prediction and control of pest emergence. We also examined the use of expert knowledge to predict hot spot locations and suggest a methodology for verifying them. 相似文献
62.
J. Casas Solis† A. Santerre M. I. Girón Pérez‡ R. Reynoso Orozco G. Zaitseva 《Journal of fish biology》2007,71(5):1541-1545
The immunological status of three native species of tilapia Oreochromis spp. and two hybrids were compared, showing a greater potential of the hybrid strain O. niloticus Rocky Mountain for aquaculture and a better capacity to resist the stressful conditions of a fish farm. 相似文献
63.
The leaf phenolics of a number of Pyrus interspecific hybrids (from controlled hand-crosses) and the parental individuals have been examined. In most instances it was found that the presence of certain phenolics in the hybrids is of diagnostic value in predicting the identities of one or both of the original parents. The flavone and flavonol glycosides appear to be inherited as simple dominant characters (whether inherited from male or female parents) but phenolics such as epicatechin, catechin, caffeoylcalleryanin and p-hydroxybenzoic acid did not always appear to show such simple dominance. 相似文献
64.
Studying polyglutamine aggregation in Caenorhabditis elegans using an analytical ultracentrifuge equipped with fluorescence detection
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Bashkim Kokona Carrie A. May Nicole R. Cunningham Lynn Richmond F. Jay Garcia Julia C. Durante Kathleen M. Ulrich Christine M. Roberts Christopher D. Link Walter F. Stafford Thomas M. Laue Robert Fairman 《Protein science : a publication of the Protein Society》2016,25(3):605-617
This work explores the heterogeneity of aggregation of polyglutamine fusion constructs in crude extracts of transgenic Caenorhabditis elegans animals. The work takes advantage of the recent technical advances in fluorescence detection for the analytical ultracentrifuge. Further, new sedimentation velocity methods, such as the multi‐speed method for data capture and wide distribution analysis for data analysis, are applied to improve the resolution of the measures of heterogeneity over a wide range of sizes. The focus here is to test the ability to measure sedimentation of polyglutamine aggregates in complex mixtures as a prelude to future studies that will explore the effects of genetic manipulation and environment on aggregation and toxicity. Using sedimentation velocity methods, we can detect a wide range of aggregates, ranging from robust analysis of the monomer species through an intermediate and quite heterogeneous population of oligomeric species, and all the way up to detecting species that likely represent intact inclusion bodies based on comparison to an analysis of fluorescent puncta in living worms by confocal microscopy. Our results support the hypothesis that misfolding of expanded polyglutamine tracts into insoluble aggregates involves transitions through a number of stable intermediate structures, a model that accounts for how an aggregation pathway can lead to intermediates that can have varying toxic or protective attributes. An understanding of the details of intermediate and large‐scale aggregation for polyglutamine sequences, as found in neurodegenerative diseases such as Huntington's Disease, will help to more precisely identify which aggregated species may be involved in toxicity and disease. 相似文献
65.
Mariko L. Frame 《Journal of Industrial Ecology》2016,20(5):1083-1093
This article assesses the impact of economic integration on Tanzania's sociometabolic profile for the years 1970–2011, which witnessed an opening and further integration of Tanzania's economy through increased trade and foreign investment, through a time‐series economy‐wide material flows analysis (EW‐MFA). The EW‐MFA results show that contrary to the trade patterns of many developing countries, increased economic integration has resulted in Tanzania becoming a net importer of resources across all material categories when measured by the physical trade balance indicator. Additionally, the article discusses the conceptual and empirical challenges of measuring ecologically unequal exchange with EW‐MFAs for developing countries whose export profiles are dominated by lightweight, high‐value precious stones and metals. It also assesses the degree to which the Tanzanian economy has undergone dematerialization over the past 40 years of economic integration. 相似文献
66.
Para‐allopatry in hybridizing fire‐bellied toads (Bombina bombina and B. variegata): Inference from transcriptome‐wide coalescence analyses
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67.
Domenico Carputo 《Sexual plant reproduction》1999,12(1):27-31
Crosses between triploid and diploid genotypes are usually the best sources of trisomics in potato as well as in several
other crop species. However, 3×× 2× crosses between triploid (2n=3×=36; 2EBN) Solanum commersonii-S. tuberosum hybrids and diploid (2n= 2×=24; 2EBN) genotypes gave progenies with a high number of extra chromosomes, 29–36, suggesting
that only eggs with 17–24 chromosomes produced embryos that reached full development. Our hypothesis is that although triploids
produce eggs with a range of chromosome numbers, 3×× 2× crosses involving a 2×(2EBN) parent favor eggs with a high chromosome
number. These eggs have higher probabilities of possessing the same endosperm balance number (EBN) value (i.e. 1) of gametes
produced by the 2EBN diploid parent to give the required 2:1 maternal to paternal EBN ratio in the hybrid endosperm. Under
this model, trisomics are produced only if the diploid parent has an EBN of 1. Based on our results and those reported in
the literature, it is proposed that in 3×(2EBN) × 2×(2EBN) crosses the endosperm balance number exercises negative selection
for gametes with a low chromosome number, and a corresponding low EBN, and positive selection for gametes with a high chromosome
number and EBN.
Received: 2 April 1998 / Revision accepted: 27 October 1998 相似文献
68.
由小麦×玉米获得的普通小麦加倍单倍体后代的RFLP变异 总被引:3,自引:0,他引:3
用小麦(Triticum aestivumL.)的rDNA克隆pTa71和与小麦基因组有部分同源性的玉米(ZeamaysL.)DNA克隆作探针,对由小麦x玉米获得的普通小麦加倍单倍体(DH)后代群体进行RFLP分析。结果发现,不但用pTa71在这些DH后代中检测到rDNA所发生的明显的减少和扩增及非转录间隔区的限制性片段长度的变化,而且用与小麦基因组部分同源的玉米克隆MR13和MR50在一些DH后代中检测到缺失变异,特别是用MR13在普通小麦DH系的18号株的基因组中检测到大幅度的限制性片段长度的变化,即原来的4.3kb的强信号带消失,取而代之的是40.0kb、2.5kb和2.0kb三条杂交带。这可能与小麦基因组DNA较大的重排事件有关,也可能是由外源的玉米DNA插入造成的。 相似文献
69.
Haijiang Liu Jingchi Wang Bingbing Zhang Xinyu Yang John P Hammond Guangda Ding Sheliang Wang Hongmei Cai Chuang Wang Fangsen Xu Lei Shi 《Annals of botany》2021,128(7):919
Background and AimsOilseed rape (Brassica napus) is one of the most important oil crops worldwide. Phosphorus (P) deficiency severely decreases the plant height and branch number of B. napus. However, the genetic bases controlling plant height and branch number in B. napus under P deficiency remain largely unknown. This study aims to mine candidate genes for plant height and branch number by genome-wide association study (GWAS) and determine low-P-tolerance haplotypes.MethodsAn association panel of B. napus was grown in the field with a low P supply (P, 0 kg ha−1) and a sufficient P supply (P, 40 kg ha−1) across 2 years and plant height and branch number were investigated. More than five million single-nucleotide polymorphisms (SNPs) were used to conduct GWAS of plant height and branch number at two contrasting P supplies.Key ResultsA total of 2127 SNPs were strongly associated (P < 6·25 × 10−07) with plant height and branch number at two P supplies. There was significant correlation between phenotypic variation and the number of favourable alleles of associated loci on chromosomes A10 (chrA10_821671) and C08 (chrC08_27999846), which will contribute to breeding improvement by aggregating these SNPs. BnaA10g09290D and BnaC08g26640D were identified to be associated with chrA10_821671 and chrC08_27999846, respectively. Candidate gene association analysis and haplotype analysis showed that the inbred lines carrying ATT at BnaA10g09290Hap1 and AAT at BnaC08g26640Hap1 had greater plant height than lines carrying other haplotype alleles at low P supply.ConclusionOur results demonstrate the power of GWAS in identifying genes of interest in B. napus and provided insights into the genetic basis of plant height and branch number at low P supply in B. napus. Candidate genes and favourable haplotypes may facilitate marker-based breeding efforts aimed at improving P use efficiency in B. napus. 相似文献
70.
J. Philip Anderson 《Biopolymers》1998,45(4):307-321
Morphology and crystal structure of a recombinant silk-like molecule, SLP4, were studied. Wide angle x-ray scattering (WAXS) and electron diffraction revealed that SLP4 lyophilized powder and thin films were isomorphic with the silk I crystal structure. Transmission electron microscopy of SLP4 thin films demonstrated a morphology of flat, variable width, crystallites that may aggregate in an epitaxial manner. Theoretical diffraction patterns from silk I crystal structure models were critically compared with SLP4 WAXS data. The analysis concluded that while the crankshaft model is capable of describing details of the SLP4 structural data well, the out-of-register model does not explain the experimental results. In particular, the predicted intensities of the crystallographic reflections for the out-of-register model are inconsistent with the SLP4 WAXS data. © 1998 John Wiley & Sons, Inc. Biopoly 45: 307–321, 1998 相似文献