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61.
Akira Ōtakara 《Bioscience, biotechnology, and biochemistry》2013,77(1):50-60
It has been found that glycol chitin is a suitable substrate for the viscometric determination of chitinase activity, because the viscosity of its aqueous solution is not affected by the presence of added salt and the changes of pH, differing from chitosan acetate and carboxy-methyl chitin used by earlier workers. Using this substrate the viscometric activity is determined, basing on the observation that the time required to halve the viscosity of reaction mixture is inversely proportional to the amount of enzyme used. 相似文献
62.
J.F. Buyel 《Biotechnology advances》2018,36(2):506-520
Herbal remedies were the first medicines used by humans due to the many pharmacologically active secondary metabolites produced by plants. Some of these metabolites inhibit cell division and can therefore be used for the treatment of cancer, e.g. the mitostatic drug paclitaxel (Taxol). The ability of plants to produce medicines targeting cancer has expanded due to the advent of genetic engineering, particularly in recent years because of the development of gene editing systems such as the CRISPR/Cas9 platform. These technologies allow the introduction of genetic modifications that facilitate the accumulation of native pharmaceutically-active substances, and even the production heterologous recombinant proteins, including human antibodies, lectins and vaccine candidates. Here we discuss the anti-cancer agents that are produced by plants naturally or following genetic modification, and the potential of these products to supply modern healthcare systems. Special emphasis will be put on proteinaceous anti-cancer agents, which can exhibit an improved selectivity and reduced side effects compared to small molecule-based drugs. 相似文献
63.
Transient expression of the β-glucuronidase (GUS) gene introduced into Arabidopsis thaliana intact plants by T-DNA after vacuum
infiltration of Agrobacterium tumefaciens was followed. The first incidence of GUS activity was found 2 - 3 d after treatment
and a peak of activity one week after treatment in both A. thaliana races, Columbia and C24. GUS activity was sharply increased
by cultivation of Arabidopsis plants at elevated temperature (29 °C) compared to cultivation at 25 °C. The density of inocula
also influenced the GUS activity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
64.
A series of binary T-DNA vectors (pBECKS) has been created for use in theAgrobacterium-mediated genetic transformation of plants. The pBECKS series has corrected the undesirable features of the popular pBIN19
vector; the deleterious mutation within the coding sequence ofnptII has been amended and the cloning sites are now adjacent to the right border repeat in order to reduce the possibility of
producing truncated sequences of novel genes within transformants. One set of vectors incorporates various combiantions of
the marker genesgusA,C1/Lc,nptII,hph, andbar, for pursuit of early and stable transformation events. A set of constructs which contain deleted T-DNA borders in various
combinations and display predictably altered efficacies for gene transfer has also been created. A modular set of vectors
has been designed to facilitate the insertion and transfer of novel gene sequences by providing anptII-linked plant expression cassette orlacZ-multiple cloning site. A range of antibiotic resistance genes has been incorporated into the non-T-DNA part of the vectors
in order to facilitate their selection across the range ofAgrobacterium virulence strains. 相似文献
65.
L. Schauser K. Handberg N. Sandal J. Stiller T. Thykj?r E. Pajuelo A. Nielsen J. Stougaard 《Molecular & general genetics : MGG》1998,259(4):414-423
Nitrogen-fixing root nodules develop on legumes as a result of an interaction between host plants and soil bacteria collectively
referred to as rhizobia. The organogenic process resulting in nodule development is triggered by the bacterial microsymbiont,
but genetically controlled by the host plant genome. Using T-DNA insertion as a tool to identify novel plant genes that regulate
nodule ontogeny, we have identified two putatively tagged symbiotic loci, Ljsym8 and Ljsym13, in the diploid legume Lotus japonicus. The sym8 mutants are arrested during infection by the bacteria early in the developmental process. The sym13 mutants are arrested in the final stages of infection, and ineffective nodules are formed. These two plant mutant lines were
identified in progeny from 1112 primary transformants obtained after Agrobacterium tumefaciens T-DNA-mediated transformation of L. japonicus and subsequent screening for defects in the symbiosis with Mesorhizobium loti. Additional nontagged mutants arrested at different developmental stages were also identified and genetic complementation
tests assigned all the mutations to 16 monogenic symbiotic loci segregating recessive mutant alleles. In the screen reported
here independent symbiotic loci thus appeared with a frequency of ∼1.5%, suggesting that a relatively large set of genes is
required for the symbiotic interaction.
Received: 12 May 1998 / Accepted: 24 June 1998 相似文献
66.
Paul M. Sanders Anhthu Q. Bui Koen Weterings K. N. McIntire Yung-Chao Hsu Pei Yun Lee Mai Thy Truong T. P. Beals R. B. Goldberg 《Sexual plant reproduction》1999,11(6):297-322
We identified Arabidopsis thaliana sterility mutants by screening T-DNA and EMS-mutagenized lines and characterized several male-sterile mutants with defects
specific for different anther processes. Approximately 44 and 855 sterile mutants were uncovered from the T-DNA and EMS screens,
respectively. Several mutants were studied in detail with defects that included the establishment of anther morphology, microspore
production, pollen differentiation, and anther dehiscence. Both non-dehiscencing and late-dehiscencing mutants were identified.
In addition, pollenless mutants were observed with either apparent meiotic defects and/or abnormalities in cell layers surrounding
the locules. Two mutant alleles were identified for the POLLENLESS3 locus which have defects in functional microspore production that lead to the degeneration of cells within the anther locules.
pollenless3–1 contains a T-DNA insertion that co-segregates with the mutant phenotype and pollenless3–2 has a large deletion in the POLLENLESS3 gene. The POLLENLESS3 gene has no known counterparts in the GenBank, but encodes a protein containing putative nuclear localization and protein-protein
interaction motifs. The POLLENLESS3 gene was shown recently to be the same as MS5, a previously described Arabidopsis
thaliana male-sterility mutant. Three genes were identified in the POLLENLESS3 genomic region: GENEY, POLLENLESS3, and β9-TUBULIN. The segment of the Arabidopsis
thaliana genome containing the POLLENLESS3 and β9-TUBULIN genes is duplicated and present on a different chromosome. Analysis of the POLLENLESS3 expression pattern determined that the 1.3-kb POLLENLESS3 mRNA is localized specifically within meiotic cells in the anther
locules and that POLLENLESS3 mRNA is present only during late meiosis.
Received: 15 October 1998 / Revision accepted: 19 November 1998 相似文献
67.
Todd R Steck 《FEMS microbiology letters》1997,147(1):121-125
Agrobacterium tumefaciens can transfer the T-DNA region of a Ti plasmid to a recipient plant cell. An accepted model that describes the T-DNA transfer mechanism proposes that single-stranded T-complexes are transferred to a recipient plant via a conjugation-like mechanism. This model has been based on examination of a limited number of Ti plasmids. In this study, the type of processed T-DNA molecule created from multiple Ti plasmids was determined. The form of the processed T-DNA was found to vary and was correlated with whether the T-DNA region was organized as a single continuous region or two adjacent regions. 相似文献
68.
T-DNA插入位点的获得对于植物功能基因组学研究及转基因植物的筛选鉴定非常重要,但是目前常用的方法如反向PCR、半随机引物PCR等,除了操作复杂、消耗时间长外,特异性较差,效率也很低。本研究利用全基因组重测序技术,将3份转基因材料基因组DNA打包后进行重测序,利用转基因载体序列作为参考序列进行比对分析,得到4个T-DNA插入位点。对3份转基因材料进行PCR和Southern blot验证分析,成功获得了3份转基因材料全部T-DNA插入位点,其中1份材料为2拷贝插入。本文利用重测序技术建立了一种简单、可靠、高效的获取转基因植物T-DNA插入位点的方法,以期为植物功能基因组学及转基因研究奠定基础。 相似文献
69.
根癌土壤杆菌介导的丝状真菌转化* 总被引:4,自引:1,他引:3
最近研究表明,Agrobacteriumtumefaciens介导转化(ATMT)的方法,可以应用到丝状真菌中。本文将从ATMT的转化原理、转化特点、转化方法以及其在丝状真菌中的主要转化实例四个方面来着重介绍A.tumefaciens介导的丝状真菌转化的最新研究进展。并对其今后的应用前景提出了展望。 相似文献
70.
Annelies De Paepe Sylvie De Buck Katleen Hoorelbeke Jonah Nolf Ingrid Peck Anna Depicker 《The Plant journal : for cell and molecular biology》2009,59(4):517-527
For genetic transformation of plants, floral dip with Agrobacterium often results in integration of multiple T-DNA copies at a single locus and frequently in low and unstable transgene expression. To obtain efficient single-copy T-DNA transformants, two CRE/ loxP recombinase-based simplifying strategies for complex T-DNA loci were compared. A T-DNA vector with oppositely oriented loxP sites was transformed into CRE -expressing and wild-type control Arabidopsis thaliana plants. Of the primary CRE -expressing transformants, 55% harboured a single copy of the introduced T-DNA, but only 15% in the wild-type plants. However, 73% of the single-copy transformants in the CRE background showed continuous somatic inversion of the DNA segment between the two loxP sites. To avoid inversion of the loxP -flanked T-DNA segment, two T-DNA vectors harbouring only one loxP site were investigated for their suitability for CRE/ loxP recombinase-mediated resolution upon floral-dip transformation into CRE -expressing plants. On average, 70% of the transformants in the CRE background were single-copy transformants, whereas the single-copy T-DNA frequency was only 11% for both vectors in the wild-type background. Both resolution strategies yielded mostly Cre transformants in which the 35S-driven transgene expression was stable and uniform in the progeny and remarkably, also in Cre transformants with multiple T-DNA copies. Therefore, a role is proposed for the CRE recombinase in preventing inverted T-DNA repeat formation or modifying the locus chromatin structure, resulting in a reduced sensitivity for silencing. 相似文献