共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
木质素生物合成途径及调控的研究进展 总被引:50,自引:0,他引:50
木质素是植物体中仅次于纤维素的一种重要大分子有机物质,具重要生物学功能。木质素填充于纤维素构架中增强植物体的机械强度,利于疏导组织的水分运输和抵抗不良外界环境的侵袭。陆生植物的木质素合成是适应陆地环境的重要进化特征之一。然而,制浆造纸的中心环节是用大量化学品将原料中的木质素与纤维素分离,纤维素用于造纸,分离的木质素等成为造纸工业的主要废弃物,对江河湖海的污染触目惊心。脱木质素的化学品投入及废液的碱回收处理需大量耗能并增加造纸成本。饲草的木质素还影响牲畜的消化与营养吸收,木质素含量的高低是饲草优劣… 相似文献
3.
木质素生物合成及其基因工程研究进展 总被引:29,自引:0,他引:29
木质素是维管植物的一种主要组成成分,是植物适应陆地环境的重要特征之一.然而,它的存在严重影响植物材料在造纸工业与畜牧业生产中的应用,因此其生物合成调控的研究引起人们极大关注.随着各种分析技术和手段的提高,该领域研究取得了突破性的进展.该文重点阐述这些新进展,同时较系统地介绍利用基因工程技术调控木质素生物合成的研究成果,并提出一些关于更有效地利用生物技术手段改良造纸资源植物品质的建议. 相似文献
4.
5.
一、引言乙烯(C_2H_4)是植物五大内源激素之一,化学结构简单,通常以气体状态存在.它对植物的生长、发育、衰老、器官脱落和果实成熟等起着调节作用.早在本世纪初,俄国科学家Neljubow(1902)首先证实乙烯是影响植物生长发育的照明气中起作用的成分.三十年代,发现了乙烯对果实、蔬菜的成熟衰老具有强有力的促进作用,从而提出了乙烯是成熟激素的概念.直到六十年代初,由于分析技术的发展,特别是气相色谱技术的应 相似文献
6.
7.
8.
9.
林可霉素(lincomycin)是由林可链霉菌(Streptomyces lincolnensis)产生的酰胺类抗生素,在临床上主要用于治疗革兰氏阳性菌引起的感染。鉴于其具有高药用价值和经济价值,林可霉素生物合成和分子调控备受关注,并取得了较好的研究进展。本文综述了林可霉素的特征结构和生物合成,并重点介绍了林可链霉菌中林可霉素的分子调控机制等方面的研究进展,有利于深入认识林可链霉菌次级代谢调控网络,为在林可霉素高产菌中改造调控因子或其靶点元件提高产量提供理论指导。 相似文献
10.
11.
Mistletoe lignin was a typical angiosperm one based on the spectral (UV, IR, 13C-NMR) and functional group analyses, and on degradation products (nitrobenzene oxidation and acidolysis), the analytical results of which were compared with those of the host lignin. l-Phenylalanine-[U-14C] was efficiently incorporated into mistletoe lignin. Phenylalanine ammonia-lyase and cinnamate-4-hydroxylase were detected by incubation of the tissue slices under illumination. It was also found that O-methyltransferase activity of the crude homogenate catalysed the methylation of 5-hydroxyferulic but not the methylation of caffeic acid. However, the latter methylation activity could be recovered by purification. These results indicate that mistletoe lignin is synthesized independently from that of its host. 相似文献
12.
p-Hydroxycinnamate:CoA ligases were extracted from the xylems of angiosperms and gymnosperms, and the substrate specificities toward ferulate and sinapate were examined. Most of angiosperm and gymnosperm CoA ligases examined were active with ferulate but not with sinapate; however, the enzymes of Erythrina crista-galli, Robinia pseudoacacia and bamboo showed considerable activity with sinapate. The other enzymes, although inactive with sinapate, showed no inhibitory effect on the Erythrina CoA ligase reaction with sinapate. The Kms for sinapate and ferulate of the Erythrina enzyme were 1.0 and 2.1 μM, respectively, and p-hydroxycinnamate was the best substrate among cinnamates examined. The MW of the CoA ligase was 40 000 and the pH optimum was between 7.2 and 7.6. The possible roles of p-hydroxycinnamate:CoA ligase in lignin biosynthesis are discussed. 相似文献
13.
14.
15.
木质素代谢的生理意义及其遗传控制研究进展 总被引:26,自引:1,他引:26
木质素含量及其相关酶系活性与植物的生长发育、抗病性、抗逆性密切相关.在造纸工业中,木质素处理是造成环境污染的重要来源。本文对木质素代谢在植物生长发育过程中的生理意义及近年来通过控制PAL、4CL、CAD、POD等酶的活性调节木质素含量或改变其组分方面的研究进展进行了综合评述,并对今后的林木育种工作进行了展望。 相似文献
16.
Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material. It is degraded and
modified by bacteria in the natural world, and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.
Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling, erosion, and cavitation. With the advantages
of immense environmental adaptability and biochemical versatility, bacteria deserve to be studied for their ligninolytic potential. 相似文献
17.
Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential. 相似文献
18.
19.
Experiments using 14C-phenylalanine have shown that ethylene treatment of swede root tissue promotes the utilization of phenylalanine as a precurso 相似文献
20.
Altered lignin biosynthesis using biotechnology to improve lignocellulosic biofuel feedstocks 总被引:1,自引:0,他引:1
Charleson R. Poovaiah Madhugiri Nageswara‐Rao Jaya R. Soneji Holly L. Baxter Charles N. Stewart Jr 《Plant biotechnology journal》2014,12(9):1163-1173
Lignocellulosic feedstocks can be converted to biofuels, which can conceivably replace a large fraction of fossil fuels currently used for transformation. However, lignin, a prominent constituent of secondary cell walls, is an impediment to the conversion of cell walls to fuel: the recalcitrance problem. Biomass pretreatment for removing lignin is the most expensive step in the production of lignocellulosic biofuels. Even though we have learned a great deal about the biosynthesis of lignin, we do not fully understand its role in plant biology, which is needed for the rational design of engineered cell walls for lignocellulosic feedstocks. This review will recapitulate our knowledge of lignin biosynthesis and discuss how lignin has been modified and the consequences for the host plant. 相似文献