Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: KEGG:D03434 (
Cellulase
)
512
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The commonly used laboratory bacterium
Escherichia coli
normally does not produce and secrete cellulases due to its complex bilayer membrane structure and poor secretory apparatus. In our previous study, the cellulolytic
E. coli
strain ZH-4 with extracellular cellulase activity was found in the bovine rumen. In this study, we demonstrate that the secretion of cellulase is a common feature of
E. coli
isolates from the rumen of animals such as sheep and cattle. Physiological phenotype characterization of these
E. coli
isolates, together with genome, transcriptome, and comparative genomics analysis, suggests their adaption to the rumen niche. The higher growth rate of the isolated strains under aerobic conditions meets the competitive requirements of the strains in rumen microecosystem, while anaerobic accumulation of reduced H
2
and succinate is hypothesized to be the results of adaptation to the rumen environment.
Cellulase
secretion increased significantly when the molecular chaperone genes
ibpA
and
ibpB
were overexpressed. This was also revealed by the transcriptomic data. A possible mechanism for cellulase secretion by
E. coli
isolates was proposed based on the transcriptomic data and molecular experiments.
IMPORTANCE
As an important intestinal microorganism,
E. coli
is present in the intestinal tract of animals and in many other environments. However, it normally does not produce and secret cellulases due to its complex bilayer membrane structure and poor secretory apparatus. Here, we proved that
E. coli
is widely present in the rumen of sheep and cattle. Systematic analysis of the isolates indicated that they have adapted to the rumen niche, with phenotypes that include secretion of cellulase and fermentative accumulation of succinate and H
2
The finding that overexpression of small
heat shock protein
genes
ibpA
and
ibpB
could facilitate cellulase BcsZ secretion, which provides a possible insight into the protein secretion mechanism of rumen-colonizing
E. coli
.
...
PMID:Systematic Analysis of Escherichia coli Isolates from Sheep and Cattle Suggests Adaption to the Rumen Niche. 3280 Nov 87
