Production of pectolytic enzymes from Erwinia grown on different carbon sources

International audienc

Biosynthetic features and properties of xylose isomerases from Arthrobacter nicotianae, Escherichia coli, and Erwinia carotovora subsp

Abstract -The characteristics of xylose isomerase biosynthesis in the bacteria Arthrobacter nicotianae BIM B-5, Erwinia carotovora subsp atroseptica jn42xylA , and Escherichia coli HB101 xylA have been studied. The bacteria produced the enzyme constitutively. Out of the carbon sources studied, D -glucose and D -xylose were most favorable for the biosynthesis of xylose isomerase in E. carotovora subsp. atroseptica , but the least appropriate in terms of the enzyme production efficiency in E. coli . Minimum and maximum levels of xylose isomerase formation in A. nicotianae were noted, respectively, during D -xylose and sucrose utilization. An addition to the D -xylose-containing nutrient medium of 0.1-1.5% D -glucose did not affect the enzyme synthesis in A. nicotianae , but suppressed it in Erwinia carotovora subsp. atroseptica (by 7% at the highest concentration) and Escherichia coli (by 63 and 75% at concentrations of 0.1 and 1.0%, respectively). The enzyme proteins produced by the bacteria exhibited the same substrate specificity and electrophoretic mobility (PAGE) as xylose isomerase A. nicotianae , although insignificant differences in the major physicochemical properties were noted

Properties of Mutants of Bacteria Belonging the Genus Erwinia Devoid of Common Components of the Phosphoenolpyruvate-Dependent Phosphotransferase System

Abstract -Biochemical consequences of mutational damage to common components of the Erwinia phosphoenolpyruvate-dependent phosphotransferase system (the HPr protein and enzyme I) were studied. The transport of glucose, mannose, fructose, and mannitol in Erwinia was shown to require a preliminary induction of proteins of the phosphotransferase system. A drastic decrease in the rate of the transport of these carbohydrates was observed in ptsI and ptsH mutants. A disturbance in the common components suppresses the synthesis of inducible enzymes ( β -galactosidase, complexes of pectolate lyases and cellulases) and renders it resistant to catabolite repression by glucose, but mutants were shown to retain intracellular cAMP content. Erwinia mutants devoid of common components of the system lack phytopathogenic features. The appearance of an intact ptsI allele in the cell completely repaired pleiotropic disturbances in these mutants