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91.
The development of Wilms' tumor, a pediatric nephroblastoma, has been associated with a deletion in the p13 region of chromosome 11. The structure and function or functions of this deleted genetic material are unknown. The role of this deletion in the process of malignant transformation was investigated by introducing a normal human chromosome 11 into a Wilms' tumor cell line by means of the microcell transfer technique. These variant cells, derived by microcell hybridization, expressed similar transformed traits in culture as the parental cell line. Furthermore, expression of several proto-oncogenes by the parental cells was unaffected by the introduction of this chromosome. However, the ability of these cells to form tumors in nude mice was completely suppressed. Transfer of other chromosomes, namely X and 13, had no effect on the tumorigenicity of the Wilms' tumor cells. These studies provide support for the existence of genetic information on chromosome 11 which can control the malignant expression of Wilms' tumor cells.  相似文献   
92.
Advances in the use of pheromones for stored-product protection   总被引:1,自引:1,他引:0  
Considerable progress has been made in the monitoring and control of stored-product pests, mainly Lepidoptera and Coleoptera, by pheromones, which are used in mass trapping, attracticide and mating disruption methods. In integrated pest management programmes of stored-product protection, the use of pheromones can lead to a reduction in chemical treatments, with economic advantages and the improvement of food-product quality. In this article, I report some promising results offering efficient detection and control of stored-product pests based on pheromones and line up a number of remaining questions to be answered to improve the reliability and competitiveness of the methods used.  相似文献   
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‘Tonda di Giffoni’ is among the most highly appreciated Italian hazelnut (Corylus avellana L.) cultivars. Due to its round kernels and excellent processing quality, it was awarded a Protected Geographical Indication (PGI) from the European Union. To identify clones expressing improved nut and production qualities, a ‘Tonda di Giffoni’ clonal selection programme was conducted across hazelnut orchards in the Irno valley of Italy from 1995 to 2006. One hundred different clones were selected and propagated in a replicated trial under similar climate, soil, and cultural conditions. From this work, the 29 best clones were identified and from 2006 to 2008 their agronomic and pomological characteristics were observed. Microsatellite or simple sequence repeat (SSR) markers were used to successfully confirm true-to-type identity of the clones. Traits evaluated included flowering time (anthesis), bud break, suckering, trunk diameter, nut and kernel characteristics and productivity (yield). Best linear unbiased predictions for clone means and estimates of intraclass correlation coefficient were obtained using R environment, lme4 and ggplot2 packages. Five clones superior to that of the standard of ‘Tonda di Giffoni’ were identified in this study. Furthermore, yield and number of suckers produced showed sufficient variability to likely be exploited for breeding. The selected clones express features useful for both growers and the processing industry and will be propagated and planted in hazelnut orchards for further study and commercial production.  相似文献   
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The exceptional efficiency of the iron chelate of ethylenediaminedi(o-hydroxyphenyl)acetic acid (o,o-EDDHA) in correcting iron chlorosis in plants and the medical applications of various metallic chelates of this compound have long been recognized. As commercial preparations of o,o-EDDHA usually contain impurities, a method for their detection is proposed. By using one- and two-dimensional nuclear magnetic resonance two impurities were identified. The structure of one of these compounds was assigned to an isomer of EDDHA containing at least one p-hydroxyphenyl moiety. The structure of the other impurity was tentatively assigned to a byproduct of the EDDHA synthesis: 2,6-di[CH(COOH)NHCH(2)CH(2)NHCH(COOH)Ar]phenol (Ar = hydroxyphenyl). Both compounds were also detected in the EDDHA extracted from a commercial iron fertilizer.  相似文献   
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On the conservative behavior of biomass water productivity   总被引:7,自引:0,他引:7  
The ever-increasing demand and competition for the finite water resource worldwide call for more efficient use of water in all sectors, including firstly agricultural food production. One important consideration is the existence of a limit to the amount of biomass a crop can produce per unit of water consumed. This article analyzes the theoretical background and the experimental evidence for the conservative behavior of the efficiency in water use by crops to produce biomass, i.e., biomass water productivity (WPb), under variable environmental conditions. Particularly, WPb is approximately constant for a given crop species after normalization for evaporative demand of the atmosphere and air carbon dioxide concentration. A stepwise scaling up approach, from leaf to canopy, is undertaken to underline the processes involved at the different hierarchical levels of biological organization that lead to the conservative behavior of WPb. Starting at the leaf level, the basic gas exchange equations are outlined to demonstrate that the normalized photosynthetic WPb at the leaf scale is proportional to the ambient CO2 concentration. New experimental evidence in support of that conclusion is presented for several C3 and a C4 crops. Additional factors are introduced to assess photosynthetic WPb at the canopy scale, including the extent of radiation capture and the role of respiration. The composition of biomass was then considered in the analysis of WPb over a season. The paper highlights the need to normalize WPb for differences in climate, specifically, in evaporative demand of the atmosphere to extrapolate WPb values between climatic zones, and in atmospheric CO2 concentration to account for changes in CO2 with time, when looking at the past and into the future. Two procedures for normalization for differences in evaporative demand are presented, and a procedure for normalization for changes in CO2 concentration is derived for the leaf scale and shown to be applicable to canopy scale. Some knowledge gaps and research needs are pointed out and the potential offered by the near constancy of normalized WPb in crop simulation modeling is emphasized.  相似文献   
100.
Mass production of the rotifer Brachionus plicatilis Müller is carried out in a set of 50-liter polyethylene bags in which first the microalga Tetraselmis suecica Butcher is cultured and then the rotifer is grown till most of the algae are grazed.This novel procedure based on a monoxenic production technique, has been conceived with a number of aims in view among which the following should be mentioned: shortest time elapsing between the start and the end of the culture (1 week); minimal care of the cultures; light energy saving for indoor invertebrate mass production systems; unified culture vessel for growing algae and rotifers; accuracy and timing of planned rotifer production. Each bag maintained in the best reported conditions gives over 400 rotifers per ml as final production. Rotifer mass production in plastic bags is better achieved when operated in conjunction with a system of continuous monoxenic cultures of microalgae and of rotifers which provide the inocula.  相似文献   
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