In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 78, No. 9 ( 2012-05), p. 3145-3155
Abstract:
Aspergillus niger is an important organism for the production of industrial enzymes such as hemicellulases and pectinases. The xylan-backbone monomer, d -xylose, is an inducing substance for the coordinate expression of a large number of polysaccharide-degrading enzymes. In this study, the responses of 22 genes to low (1 mM) and high (50 mM) d -xylose concentrations were investigated. These 22 genes encode enzymes that function as xylan backbone-degrading enzymes, accessory enzymes, cellulose-degrading enzymes, or enzymes involved in the pentose catabolic pathway in A. niger . Notably, genes encoding enzymes that have a similar function (e.g., xylan backbone degradation) respond in a similar manner to different concentrations of d -xylose. Although low d -xylose concentrations provoke the greatest change in transcript levels, in particular, for hemicellulase-encoding genes, transcript formation in the presence of high concentrations of d -xylose was also observed. Interestingly, a high d -xylose concentration is favorable for certain groups of genes. Furthermore, the repressing influence of CreA on the transcription and transcript levels of a subset of these genes was observed regardless of whether a low or high concentration of d -xylose was used. Interestingly, the decrease in transcript levels of certain genes on high d -xylose concentrations is not reflected by the transcript level of their activator, XlnR. Regardless of the d -xylose concentration applied and whether CreA was functional, xlnR was constitutively expressed at a low level.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.07772-11
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2012
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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