诱启学生思维 引发学生解决问题的兴趣——阐释我的“五步诱导”教学法

要提高小学低段数学教学中学生解决问题的能力，其关键就是教师要善于诱发学生的思维活动和解决问题的兴趣，增强学生的自信心。“五步诱导”法的核心就是对学生思维和兴趣的“诱”和“引”。在教学中采用“五步诱导”法教学，能很好的达成教学目标。

Functional genomics: Gene identification via T-DNA mediated gene trap tagging in plants

The fully sequenced genomes of Arabidopsis, rice, tomato, potato, ma ize, wheat, and soybean offer large amounts of information about cellular and de velopmental biology. It is a central challenge of genomics to use this informati on in discovering the function of proteins and identifying developmentally impor tant genes. Although classical genetic approaches to gene identification which r ely on disruption of a gene leading to a recognizable phenotype continues to be an extremely successful one, T-DNA mediated gene trap tagging which has been dev eloped that utilize random integration of reporter gene constructs has also prov en to be an extremely powerful tool in plant cellular developmental biology. In this review, how gene trap tagging, promoter trap tagging, and enhancer trap tag ging detection systems have been applied to plant biology is described and these gene identification techniques could be useful to the plant molecular biology a nd plant biotechnology community.

Characterization of promoters in Escherichia coli and application for xylitol synthesis

Promoters are the most important tools to control and regulate the gene expression in synthetic biology and metabolic engineering. The expression of target genes in Escherichia coli is usually controlled by the high-strength inducible promoter with the result that the abnormally high transcription of these genes creates excessive metabolic load on the host, which decreases product formation. The constitutive expression systems are capable of avoiding these defects. In this study, to enrich the application of constitutive promoters in metabolic engineering, four promoters from the glycolytic pathway of E. coli were cloned and characterized using the enhanced green fluorescent protein as reporter. Among these promoters, Pgap Awas determined as the strongest one, the strength of which was about 8.92% of that of the widely used inducible promoter PT7. This promoter was used to control the expression of heterologous xylose reductase in E. coli for xylitol synthesis so as to verify its function in pathway engineering. The maximum xylitol titer(40.6 g·L-1) produced by engineered E. coli under the control of the constitutive promoter Pgap Awas obviously higher than that under the control of the inducible promoter PT7,indicating the feasibility and superiority of promoter Pgap Ain the metabolic engineering of E. coli.

Regulated Gene Expression with Promoters Responding to Inducers

Genetically engineered transgenic animals and plants have proven to be extremely useful for analyzing biochemical and developmental processes.Promoters responding to chemical inducers will be powerful tools for basic research in molecular biology and biotechnological applications.Various chemical inducible systems based on activation and inactivation of the target gene had been described.The transfer of regulatory elements from prokaryotes,insects,and mammals has opened new avenues to construct chemically inducible promoters that differ in their ability to regulate the temporal and spatial expression patterns,and this will dramatically increase the application of transgenic technology.This review provides an overview on regulation of gene expression,promoter activating systems,promoter inactivation systems,inducible gene over expression,and inducible anti suppression.

Evaluation on Inducible Effect of pOp6 Promoter in Transgenic Rice

In order to analyze the Oslbglu4 phenotype, the inducible promoter of the transgenic rice which knock-down the Oslbglu4 expression was assessed. The result showed that 30 μM dexamethasone（DEX） had the stronger induction effect than 10 μM DEX by β-Glucuronidase （GUS） staining, qRT-PCR further verified the Oslbglu4 gene deletion. The effect of DEX and its solvent absolute ethanol on seed development was measured, and no significant effect was observed. The conclusion is that final concentration of DEX at 30 μM is suitable for pOp6 promoter induction.

Metabolomics Study in Methylotrophic Yeast： A Minireview

Methylotrophic yeast has been used as a cost-effective and valuable host for expression of recombinant protein due to its unique methanol utilisation pathway. It has an AOX （alcohol oxidase） protein which has been characterised to be a strong and tightly methanol-inducible dependent promoter. Metabolomics is the systematic study and inclusive analysis of small molecules called metabolites in a biological system. Metabolomics plays an important part in connecting the phenotype and genotype gap because it magnifies the modifications in the proteome and provides a better phenotype representation of an organism. This quantitative study has provided a new perception on the metabolic burden derived from the overexpression of recombinant protein in methylotrophic yeast. In this review, we discuss the fundamental aspect of metabolomics in methylotrophic yeast followed by their latest developments.