1,721,023 research outputs found
Growth phase-dependent expression of an endoglucanase encoding gene (eglS) in Streptomyces rochei A2
No full textDifferent growth phases of Streptomyces rochei A2, a cellulolytic strain isolated from termite gut, were determined in liquid culture. The strain exhibited a multiphasic growth curve typical of streptomycetes. In S. rochei A2, the secreted endoglucanase EglS is coded by a TTA-containing gene, conserved in other Streptomyces. The onset of S. rochei A2 eglS gene expression was determined by RT-PCR using total RNA extracted at different growth phases. The eglS gene was expressed only during transition, second rapid growth and stationary phases, the timing of expression being transcriptionally regulated
A putative sigma factor from Streptomyces sp. strain A21 can activate the expression of the cryptic operon bgl in Escherichia coli K-12
No full textStreptomyces sp A21 is a cellulolytic strain isolated from soil which was assigned to the genus Streptomyces on the basis of distinctive morphological features. A genomic library of A21 DNA has been constructed and transformed into Escherichia coli K-12 using a high-copy-number vector. One of the recombinant plasmids activates the cryptic bgl operon when inserted into appropriate strains. The complete sequence of the 1629-bp A21 DNA fragment has been determined. The analysis revealed the presence of an ORF whose putative product shows a high degree of similarity to RNA polymerase sigma factors; we therefore designated the gene psfS ((P) under bar utative (s) under bar igma (f) under bar actor, (S) under bar treptomyces). Mapping of the 5' terminus of transcript by primer extension indicated that PsfS induces transcription initiation within the bgl promoter-silencer region
Characterization of bacterial pectinolytic strains involved in the water retting process
No full textClostridium felsineum and Clostridium acetobutylicum are two distinct species that are phylogenetically closely related
No full textA putative Streptomyces sigma factor can activate the expression of the cryptic operon bgl in Escherichia coli K-12.
No full textStreptomyces sp A21 is a cellulolytic strain isolated from soil which was assigned to the genus Streptomyces on the basis of distinctive morphological features. A genomic library of A21 DNA has been constructed and transformed into Escherichia coli K-12 using a high-copy-number vector. One of the recombinant plasmids activates the cryptic bgl operon when inserted into appropriate strains. The complete sequence of the 1629-bp A21 DNA fragment has been determined. The analysis revealed the presence of an ORF whose putative product shows a high degree of similarity to RNA polymerase sigma factors; we therefore designated the gene psfS (Putative sigma factor, Streptomyces). Mapping of the 5' terminus of transcript by primer extension indicated that PsfS induces transcription initiation within the bgl promoter-silencer region
Selezione e caratterizzazione di ceppi batterici per il miglioramento del processo di macerazione della canapa
No full textRestriction enzyme and DNA hybridization analysis of cellulolytic Streptomyces isolates of different origin
No full textStreptomyces rochei A2 endoglucanase (eglS) and β-glucosidase (bgs1) genes were used as probes to survey their distribution among 16 Streptomyces strains isolated from different sources and characterized for their cellulolytic activities. The eglS probe hybridized to the genomic DNA of 12 strains with a restriction pattern different from that of S. rochei A2. The DNA from all strains, except one, hybridized with the bgs1 probe and one strain showed the same restriction pattern as seen in S. rochei A2. The sequence localized by the eglS probe in S. thermoviolaceus and the one localized by the bgs1 probe in strain EC1 were cloned and expressed in E. coli in plasmids pTAE and pCSF203, respectively. The restriction maps showed that the cloned genes were identical to eglS and bgs1. The restriction enzyme analysis of genomic DNA from all the strains identified nine different groups, each characterized by a distinctive pattern and in agreement with the results of the hybridization experiments
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