Promoter-like mutants with increased expression of the Escherichia coli uridine phosphorylase structural gene

Миронов, А.; Sukhodolets, V. V.

doi:10.1128/jb.137.2.802-810.1979

Cited by 9 publications

(1 citation statement)

References 21 publications

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“…F. succinogenes binds tightly to the surface of plant materials via adhesions leading to extensive plant cell wall degradation [148–151]. Three F. succinogenes enzymes, the endoglucanases EG2 and EGF and the chloride‐stimulated cellobiosidase, are likely to contain a CBM, and may be involved in bacterial adhesion to cellulose [152,153].…”

Section: Adherence To Cellulose and Evidence For The Cellulosomementioning

confidence: 99%

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

et al. 2003

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The degradation of plant cell walls by ruminants is of major economic importance in the developed as well as developing world. Rumen fermentation is unique in that efficient plant cell wall degradation relies on the cooperation between microorganisms that produce fibrolytic enzymes and the host animal that provides an anaerobic fermentation chamber. Increasing the efficiency with which the rumen microbiota degrades fiber has been the subject of extensive research for at least the last 100 years. Fiber digestion in the rumen is not optimal, as is supported by the fact that fiber recovered from feces is fermentable. This view is confirmed by the knowledge that mechanical and chemical pretreatments improve fiber degradation, as well as more recent research, which has demonstrated increased fiber digestion by rumen microorganisms when plant lignin composition is modified by genetic manipulation. Rumen microbiologists have sought to improve fiber digestion by genetic and ecological manipulation of rumen fermentation. This has been difficult and a number of constraints have limited progress, including: (a) a lack of reliable transformation systems for major fibrolytic rumen bacteria, (b) a poor understanding of ecological factors that govern persistence of fibrolytic bacteria and fungi in the rumen, (c) a poor understanding of which glycolyl hydrolases need to be manipulated, and (d) a lack of knowledge of the functional genomic framework within which fiber degradation operates. In this review the major fibrolytic organisms are briefly discussed. A more extensive discussion of the enzymes involved in fiber degradation is included. We also discuss the use of plant genetic manipulation, application of free-living lignolytic fungi and the use of exogenous enzymes. Lastly, we will discuss how newer technologies such as genomic and metagenomic approaches can be used to improve our knowledge of the functional genomic framework of plant cell wall degradation in the rumen.

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Section: Adherence To Cellulose and Evidence For The Cellulosomementioning

confidence: 99%

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

et al. 2003

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Chromosomal Rearrangements Affecting the Regulation of Uridine Phosphorylase Gene Expression in Escherichia Coli

Миронов

Kulakauskas

Sukhodolets

1988

Metabolism and Enzymology of Nucleic Acids

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Influence of the rho-15 temperature-sensitive (ts) mutation on the expression of the deo−operon in Escherichia coli

1982

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In the rho-15 temperature-sensitive (ts) mutant deo-operon enzymes show no sensitivity to catabolite repression and are not derepressed under the influence of a constitutive regulatory mutation, cytR. These data suggest that intact Rho-protein along with CRP protein is necessary for a catabolite sensitive deo-operon promoter cytP to work. In addition, there are data suggesting that Rho-factor and CRP-protein interact with each other in regulation of the deo-operon. Thus, in studies of the effect of the rho-15 (ts) and crp mutations, maximum deo-enzyme levels have been found in the double rho-15 (ts) crp mutant, and therefore intact Rho-protein in the crp genome or intact CRP-protein on the rho-15 (ts) background seems to be an obstacle for the deoP promoter in the deo-operon. In rho-15 (ts) a relative increase has been observed in the enzyme activity for a distal purine nucleoside phosphorylase gene with respect to a proximal thymidine phosphorylase gene. However in crp, the rho-15 (ts) mutation has no effect on the polarity gradient, that is on the background of impaired CRP protein Rho-factor does not seem to work as a transcription terminator within the operon.

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Promoter-like mutants with increased expression of the Escherichia coli uridine phosphorylase structural gene

Cited by 9 publications

References 21 publications

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

Opportunities to improve fiber degradation in the rumen: microbiology, ecology, and genomics

Chromosomal Rearrangements Affecting the Regulation of Uridine Phosphorylase Gene Expression in Escherichia Coli

Influence of the rho-15 temperature-sensitive (ts) mutation on the expression of the deo−operon in Escherichia coli

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