@entity20423 produces an extracellular multienzyme complex, termed cellulosome, that allows efficient solubilization of crystalline cellulose. One of the major enzymes in this complex is the CelS (Cel48A) exoglucanase. The regulation of CelS at the protein and transcriptional levels was studied using batch and continuous cultures. The results of @entity3208 - @entity2975 gel electrophoresis and Western blot analyses indicated that the amount of CelS in the supernatant fluids of @entity8692 -grown cultures is lower than that of cellulose-grown cultures. The transcriptional level of celS mRNA was determined quantitatively by RNase protection assays with batch and continuous cultures under @entity505 and @entity1568 limitation. The amount of celS mRNA transcripts per cell was about 180 for cells grown under @entity505 limitation at growth rates of 0.04 to 0.21 h(-1) and 80 and 30 transcripts per cell for batch cultures at growth rates of 0.23 and 0.35 h(-1), respectively. Under @entity1568 limitation, the corresponding levels were 110, 40, and 30 transcripts/cell for growth rates of 0.07, 0.11, and 0.14 h(-1), respectively. Two major transcriptional start sites were detected at positions -140 and -145 bp, upstream of the translational start site of the celS gene. The potential promoters exhibited homology to known sigma factors (i.e., sigma(A) and sigma(B)) of @entity3881 . The relative activity of the two promoters remained constant under the conditions studied and was in agreement with the results of the RNase protection assay, in which the observed transcriptional activity was inversely proportional to the growth rate.

Regulation of the cellulosomal CelS (cel48A) gene of XXXX is growth rate dependent.

@entity1568 :: ('MESH:D009584', 'Chemical') :: ['nitrogen'] @entity3208 :: ('MESH:D012967', 'Chemical') :: ['sodium dodecyl sulfate'] @entity20423 :: ('1515', 'Species') :: ['Clostridium thermocellum'] @entity8692 :: ('MESH:D002475', 'Chemical') :: ['cellobiose'] @entity2975 :: ('CHEBI:51135', 'Chemical') :: ['polyacrylamide'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity3881 :: ('1423', 'Species') :: ['Bacillus subtilis']
@entity20423 :: (1515,Species) :: ['Clostridium thermocellum']
