TY - JOUR
T1 - Possible mechanisms underlying the slow lactose fermentation phenotype in Shigella spp.
AU - Ito, H.
AU - Kido, N.
AU - Arakawa, Y.
AU - Ohta, M.
AU - Sugiyama, T.
AU - Kato, N.
PY - 1991
Y1 - 1991
N2 - A Southern hybridization analysis revealed that the region homologous to Escherichia coli lacZ was present on the chromosomal DNAs of β-galactosidase-positive Shigella strains, such as Shigella dysenteriae serovar 1 and Shigella sonnei strains, whereas this region was absent from chromosomal DNAs of β-galactosidase-negative strains of Shigella flexneri and Shigella boydii. We found that the lacY-A region was deficient in S. dysenteriae serovar 1 and believe that this is the reason for the slow fermentation of lactose by this strain. S. sonnei strains possessed the region which hybridized with E. coli lacY-A despite their slow hydrolysis of lactose. The whole lactose-fermenting region was cloned from S. sonnei and compared with the cloned lac operon of E. coli K-12. Both clones directed the synthesis of β-galactosidase in an E. coli K-12 strain lacking indigenous β-galactosidase activity (strain JM109-1), and we observed no difference in the expression of β-galactosidase activity in S. sonnei and E. coli. However, E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei exhibited the slow lactose fermentation phenotype like the parental strain. S. sonnei strains had no detectable lactose permease activities. E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei had a detectable permease activity, possibly because of the multicopy nature of the cloned genes, but this permease activity was much lower than that of strain JM109-1 harboring the lac operon of E. coli K-12. From these results we concluded that slow lactose fermentation by S. sonnei is due to weak lactose permease activity.
AB - A Southern hybridization analysis revealed that the region homologous to Escherichia coli lacZ was present on the chromosomal DNAs of β-galactosidase-positive Shigella strains, such as Shigella dysenteriae serovar 1 and Shigella sonnei strains, whereas this region was absent from chromosomal DNAs of β-galactosidase-negative strains of Shigella flexneri and Shigella boydii. We found that the lacY-A region was deficient in S. dysenteriae serovar 1 and believe that this is the reason for the slow fermentation of lactose by this strain. S. sonnei strains possessed the region which hybridized with E. coli lacY-A despite their slow hydrolysis of lactose. The whole lactose-fermenting region was cloned from S. sonnei and compared with the cloned lac operon of E. coli K-12. Both clones directed the synthesis of β-galactosidase in an E. coli K-12 strain lacking indigenous β-galactosidase activity (strain JM109-1), and we observed no difference in the expression of β-galactosidase activity in S. sonnei and E. coli. However, E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei exhibited the slow lactose fermentation phenotype like the parental strain. S. sonnei strains had no detectable lactose permease activities. E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei had a detectable permease activity, possibly because of the multicopy nature of the cloned genes, but this permease activity was much lower than that of strain JM109-1 harboring the lac operon of E. coli K-12. From these results we concluded that slow lactose fermentation by S. sonnei is due to weak lactose permease activity.
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U2 - 10.1128/aem.57.10.2912-2917.1991
DO - 10.1128/aem.57.10.2912-2917.1991
M3 - Article
C2 - 1746953
AN - SCOPUS:0025953959
SN - 0099-2240
VL - 57
SP - 2912
EP - 2917
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 10
ER -