Article Abstract:
Alpha-amylase expressed in Escherichia coli from the alpha-amylase gene of Xanthomonas campestris K-11151 has properties similar to that of the original enzyme. The gene is cloned into E. coli using pUC19 as a vector. The enzyme is expressed in E. coli from the lac promoter of the vector and transported to the periplasmic region. The thermal stability, substrate preferences and optimal temperature are the same as that of the X. campestris enzyme. The enzyme hydrolyzes maltotetraose and higher maltooligosaccharides to synthesize glucose from maltose.
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Article Abstract:
An extrachromosal DNA, EcOYW1, from onion yellows phytoplasma (OY-W) is reported. The complete nucleotide sequence of EcOYW1 was found. The replicon was shown to encode a homologue of geminivirus replication protein Rep, but not found in OY-M, a mild symptom line derived from OY-W. It appears it may be related to the pathogenicity of OY-W. Plant pathogenic phytoplasmas are prokaryotes lacking cell walls and associated with various plant diseases including some in garland chrysanthemums.
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Article Abstract:
Strains carrying a chromsomal lrp::lacZ fusion were used to determine the factors which affects the metabolic regulation of lrp gene expression in Escherichia coli K-12. Results reveal that expression of the lrp gene is regulated in part by the nutrients available to the cell. Furthermore, it was found that expression of target genes increases when lrp production is increased in a given medium.
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