Supra-operonic clustering of genes specifying glucose dissimilation in Pseudomonas putida

Abstract

The linkage arrangements of genes governing glucolysis in Pseudomonas putida have been determined by transductional analysis. Five genes (gdh, kgtA, kgtB, edd and eda), comprising at least three operons, are contransducible with each other, but not with ggu (glucose and gluconate uptake) nor with genes of a known supra-operonic cluster of genes specifying enzymes of other dissimilatory pathways, nor with a biochemically uncharacterized his marker. It thus appears that P. putida may have more than one chromosomal region in which genes with dissimilatory function are clustered in a supro-operonic fashion.

Mutants in Glucose Metabolism

“…Glucose dehydrogenase mutants may (188) or may not (181,190) grow on glucose, but problems with induction complicate interpretation (77). Mutants lacking 2-ketogluconokinase or 2-ketogluconate-6-P reductase were cited as growing very slowly on glucose or gluconate (181). These results generally support the primacy, in aerobic growth, of the route via gluconate.…”

“…Thus, phosphoglucose isomerase mutants in Rhizobium and Pseudomonas (178)(179)(180), grow normally on glucose and glu con ate but not on substances catabolized via fructose-6-P, such as mannitol. Mutants blocked in the Entner-Doudoroff pathway are blocked in growth on gIuconate and glucose as well (180)(181)(182)(183)(184)(185)(186). Even when present, 6-phosphogluconate dehydrogenase and the nonoxidative pentose-phosphate pathway are generally insufficient for growth of the latter mutants (177,183).…”

“…Accordingly, Pseudomonas aeruginosa mutants lacking glucose-6-P de hydrogenase did not grow on glucose anaerobically with nitrate (189) but did grow aerobically on glucose (179,180) although a lag was noted (179). Glucose dehydrogenase mutants may (188) or may not (181,190) grow on glucose, but problems with induction complicate interpretation (77). Mutants lacking 2-ketogluconokinase or 2-ketogluconate-6-P reductase were cited as growing very slowly on glucose or gluconate (181).…”

Galactose catabolism in Caulobacter crescentus

“…In addition to the basic enzymatic differences in hexose catabolism exhibited by the enterics and Pseudomonas, the sole use of the Entner-Doudoroff enzymes requires independent pathways for utilization of different hexoses (1,3). Moreover, regulation of gene expression for catabolic enzymes in Pseudomonas, as well as gene organization, also differs from that observed in the enteric bacteria (2,4,7,10,16). The genes for glucose catabolism in Pseudomonas putida are independently regulated although they map in a chromosomal cluster (2).…”

“…Moreover, regulation of gene expression for catabolic enzymes in Pseudomonas, as well as gene organization, also differs from that observed in the enteric bacteria (2,4,7,10,16). The genes for glucose catabolism in Pseudomonas putida are independently regulated although they map in a chromosomal cluster (2). Furthermore, other catabolic pathways in both P. putida (2,7,16) and P. aeruginosa (4,10) appear to be similarly regulated.…”