Mutations Affecting the Dissimilation of Mannitol by Escherichia coli K-12

Abstract

Mutants of Escherichia coli K-12 defective in the mannitol-specific enzyme II complex of the phosphoenolpyruvate phosphotransferase system (PTS) or lacking mannitol-1-phosphate dehydrogenase have been isolated. These mutants fail only to grow on mannitol. Growth of the dehydrogenase-negative mutant on casein hydrolysate can be abruptly inhibited by exposure to mannitol. A mutant with constitutive expression of both of these enzymes has also been isolated. All three mutations are clustered in a region represented at min 71 of the Taylor map. In a mutant with less than 5% of the activity of enzyme I of the PTS, both the enzyme II complex and the dehydrogenase remain inducible by mannitol. In the mutant defective in the enzyme II complex, mannitol is able to induce the dehydrogenase. Thus, mannitol, rather than its phosphorylated product, seems to be the inducer.

Isolation, characterization, and nucleotide sequence of the Streptococcus mutans mannitol-phosphate dehydrogenase gene and the mannitol-specific factor III gene of the phosphoenolpyruvate phosphotransferase system

“…Isolation of the S. mutans mannitol PTS genes. In mtlD mutants, growth in the presence of mannitol results in accumulation within the cell of mannitol-1-phosphate, which is growth inhibitory (36). This provided a strong selective mechanism to isolate the streptococcal genes involved with mannitol utilization.…”

“…Fructose-6-phosphate is then metabolized by the glycolytic pathway. Strong selective pressure for isolation of the streptococcal gene was possible because of accumulation of toxic mannitol-1-phosphate, which is formed when an mtlD mutant is placed in the presence of mannitol (36). This selective pressure is evident by the isolation of plasmids containing the same 2.3-kb PstI fragment from S. mutans in two separate cloning experiments using this selection procedure.…”

“…X6224 is a CC118 derivative that contains transposon TnSseql (28) inserted into the chromosome at an unknown position. A derivative of L239 (19,36) was used for mannitol complementation assays. L239 is an mtlD mutant and was transduced to an hsdR mutant by using a P1L4 lysate (6) propagated on MOB145 hsdR (39) by selection for tetracycline resistance.…”

FIS is a regulator of metabolism in Escherichia coli

“…CSH50 (ara A(lac pro) strA thi), Miller 1972; JC7326 (recB27 recC22 sbcB75), Winans et a/., 1985;mc4100 (rbsR), Silhavy eta/., 1984. The following strains were kindly provided by €3. Bachmann: Lin7 (glpR2), Hayashi eta/., 1964; Lin238 (mt/R72), Solomon and Lin, 1972;S0303 (deoR 201), Hammer-Jespersen and Munch-Petersen, 1975;S0664 (cytRS), Hammer-Jespersen and Nygaard, 1976; S0744 (deoff208 cytRB), Hammer-Jespersen and Nygaard, 1976. CSH50 A f i s was constructed as follows: the fis gene in plasmid pCF221 (Koch eta/., 1988) was deleted by restriction at Hind1 and Bglll sites and replaced by a 1.3 kb Haell fragment from pACYCl84 encoding the cat gene.…”

The mtl genes and the mannitol-1-phosphate dehydrogenase from Klebsiella pneumoniae KAY2026

“…This phosphate is converted by an NAD-dependent dehydrogenase (MtlD) into D-fructose 6-phosphate (Fru6P) as has been shown for Escherichia coli, Klebsiella pneumoniae (Aerobacter aerogenes) and Salmonella typhimurium [1^4]. The genes for the transporter and the dehydrogenase, mtlA and mtlD, respectively, are clustered in the mtl operon together with gene mtlR for a putative repressor [3^5] and the system is inducible by Mtl in the medium [4]. The mtl genes from E. coli K-12 [6,7] and from four Gram-positive species have been sequenced [8^11].…”