共查询到19条相似文献,搜索用时 62 毫秒
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代谢工程分为推理性代谢工程和逆代谢工程,逆代谢工程是避开对代谢网络充分认识的一种全新的遗传工程。本简要介绍了逆代谢工程的策略,并以实例详细分析了逆代谢工程的具体应用,最后,分析了逆代谢工程的问题和发展前景。 相似文献
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植物代谢工程是一个很有发展前景的新兴学科。它可通过多种方法对植物的代谢流进行改造,如加速限制步骤的反应,改变分叉代谢途径的流向,构建代谢旁路,引入转录调节因子、信号因子、植物激素合成基因,扩展和构建新的代谢途径等方法进行。并取得了一些有意义的研究结果。 相似文献
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维生素C生物转化的代谢工程研究 总被引:1,自引:2,他引:1
本从代谢工程角度出发,综述维生素C(Vc)生物转化代谢研究进展。分别论述了3条产生Vc重要前体2-酮基-L-古龙酸(2-KLG)反应路线的代谢机制、反应酶系及代谢工程菌构建等方面的问题;并对Vc生物转化应用前景作了展望。 相似文献
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紫杉醇生物合成途径及调控研究进展 总被引:8,自引:0,他引:8
本文综述了紫杉醇的生物合成途径、代谢调控及基因工程方面的研究进展,总结了代谢调控与基因工程方法提高红豆杉属植物细胞培养紫杉醇合成量的研究状况,并在探讨生物合成途径理论的基础上,对紫杉醇生物合成的限速步骤进行了阐述,指出解决侧链合成的根速步骤问题会显著提高紫杉醇的生物合成量。 相似文献
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生态工程中食物链组合的环分析 总被引:1,自引:0,他引:1
本文研究了一个用于治理水体生态系统富营养化的生态工程,应用环分析方法对工程中的食物链的组合进行了分析。在这里,贝类被用于清除过量的藻类;种植水生植物改变营养的流转途径并且放养食植性鱼类,通过捕捞鱼和贝,使水体中的有机物和无机盐沿着从藻类到贝类和从水生植物到食植性鱼类两条途径由水体生态系统中输出,应用环分析的手段,可以调整生态工程中食物链的组合结构,使整个生态工程具有某种特定的功能。 相似文献
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Alexander E. Vinogradov 《Evolution; international journal of organic evolution》1995,49(6):1249-1259
The body-mass-corrected rate of basal metabolism in mammals is found to be negatively correlated with genome size, which is possibly linked to average cell size. The correlation, already significant at the species level (rsp = –0.61, P < 0.0002), gradually strengthens as mean values for higher taxonomic levels (genera, families, and orders) are substituted in place of the species points (rgen = –0.65, P < 0.0002; rfam = –0.71, P < 0.0004; rord = –0.81, P < 0.008). This finding suggests that a sizeable part of the mammalian (above 25% of human) genome can be used for evolutionary adjustment of metabolic rate resulting from nucleotypic effect independently of body size. The total variance of mammalian genome-size values is found to be divided into two parts: within genera (43%) and taxonomic levels higher than order (57%), with no tangible variance being added between these taxonomic levels; whereas the body-mass-corrected rate of basal metabolism varies mainly at family (42%) and order (53%) levels. The only order for which there seems to be a necessary minimum of data for intraorder analysis (rodents) shows a not statistically significant correlation at the species level (rsp = –0.47; P < 0.09), significant at the genus level (rgen = –0.74; P < 0.04), and very high at the family level (rfam = –0.98; P < 0.03). The concept of ultimate (distant) characters consolidation is proposed. In birds, with average genome sizes 40% of those of mammals, and similarly narrower ranges both of genome sizes and of body-mass-corrected metabolic rates, the correlation was not significant. 相似文献
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Richard G. Harrison Steven M. Bogdanowicz 《Evolution; international journal of organic evolution》1997,51(2):493-505
The distribution of multilocus genotypes found within a natural hybrid zone is determined by the sample of genotypes present when the hybrid zone first formed, by subsequent patterns of genetic exchange between the hybridizing taxa, and by drift and selection within each of the hybrid zone populations. We have used anonymous nuclear DNA restriction fragment polymorphisms (RFLPs) to characterize the array of multilocus genotypes present within a well-studied hybrid zone between two eastern North American field crickets, Gryllus pennsylvanicus and Gryllus firmus. These crickets hybridize along a zone of contact that extends from New England to Virginia. Previous studies have shown that both premating and postmating barriers exist between the two cricket species, but the absence of diagnostic morphological and allozyme markers has made it difficult to assess the consequences of these barriers for genetic exchange. Analyses based on four diagnostic anonymous nuclear markers indicate that hybrid zone populations in Connecticut contain few F1 hybrids, and that nonrandom associations persist among nuclear gene markers, between nuclear and cytoplasmic markers, and between molecular markers and morphology. Field cricket populations within the hybrid zone are not “hybrid swarms” but consist primarily of crickets that are very much like one or the other of the parental species. Despite ample opportunity for genetic exchange and evidence for introgression at some loci, the two species remain quite distinct. Such a pattern appears to be characteristic of many natural hybrid zones. 相似文献