scholarly journals New locus (ttr) in Escherichia coli K-12 affecting sensitivity to bacteriophage T2 and growth on oleate as the sole carbon source.

1986 ◽  
Vol 168 (2) ◽  
pp. 534-540 ◽  
Author(s):  
R Morona ◽  
U Henning
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
K 12 ◽  
Bacteriophage T2

scholarly journals DsdX Is the Second d-Serine Transporter in Uropathogenic Escherichia coli Clinical Isolate CFT073

2006 ◽  
Vol 188 (18) ◽  
pp. 6622-6628 ◽  
Author(s):  
Andrew T. Anfora ◽  
Rodney A. Welch
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Carbon Source ◽  
Clinical Isolate ◽  
Sole Carbon Source ◽  
Minimal Medium ◽  
Amino Acid Sequence Similarity ◽  
Predicted Amino Acid Sequence ◽  
E Coli ◽  
K 12

ABSTRACTd-Serine is an amino acid present in mammalian urine that is inhibitory toEscherichia colistrains lacking a functionaldsdAgene. Counterintuitively, adsdAstrain ofE. coliclinical isolate CFT073 hypercolonizes the bladder and kidneys of mice relative to wild type during a coinfection in the murine model of urinary tract infection. We are interested in the mechanisms for uptake ofd-serine in CFT073.d-Serine entersE. coliK-12 via CycA, thed-alanine transporter andd-cycloserine sensitivity locus. CFT073cycAcan grow on minimal medium withd-serine as a sole carbon source. ThedsdXgene of thedsdCXAlocus is a likely candidate for an additionald-serine transporter based on its predicted amino acid sequence similarity to gluconate transporters. In minimal medium, CFT073dsdXcan grow ond-serine as a sole carbon source; however, CFT073dsdX cycAcannot. Additionally, CFT073dsdXA cycAis not sensitive to inhibitory concentrations ofd-serine during growth on glycerol andd-serine minimal medium.d-[14C]serine uptake experiments with CFT073dsdX cycAharboringdsdXorcycArecombinant plasmids confirm thatd-serine is able to enterE. colicells via CycA or DsdX. In whole-celld-[14C]serine uptake experiments, DsdX has an apparentKmof 58.75 μM and aVmaxof 75.96 nmol/min/mg, and CycA has an apparentKmof 82.40 μM and aVmaxof 58.90 nmol/min/mg. Onlyd-threonine marginally inhibits DsdX-mediatedd-serine transport, whereasd-alanine, glycine, andd-cycloserine inhibit CycA-mediatedd-serine transport. DsdX or CycA is sufficient to transport physiological quantities ofd-serine, but DsdX is ad-serine-specific permease.

Mannose utilization in Escherichia coli requires cyclic AMP but not an exogenous inducer

1980 ◽  
Vol 26 (12) ◽  
pp. 1508-1511 ◽  
Author(s):  
Ann D. E. Fraser ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Cyclic Amp ◽  
Adenylyl Cyclase ◽  
Sole Carbon Source ◽  
Receptor Protein ◽  
Deficient Mutant ◽  
Phosphotransferase System ◽  
Cyclic Amp Receptor Protein ◽  
Cyclic Monophosphate

It has not been clarified whether the utilization of mannose by Escherichia coli requires adenosine 3′,5′-cyclic monophosphate (cyclic AMP). Using an adenylyl cyclase deficient mutant (CA8306B) and a cyclic AMP receptor protein (CRP) deficient mutant (5333B) we have shown that the utilization of mannose is dependent on the cyclic AMP–CRP complex. 2-Deoxyglucose (DG) is a nonmetabolizable glucose analog specific for the phosphotransferase system (PTS) which transports mannose (termed here PTSM). Growth of CA8306B on glycerol is unaffected by addition of the analog, whereas growth of the strain on glycerol plus cyclic AMP ceases im mediately upon addition of DG. These results suggest that the formation of PTSM is dependent on cyclic AMP. In addition, CA8306B grown on glycerol plus cyclic AMP can immediately utilize mannose when transferred to a medium containing mannose as a sole carbon source, whereas the same strain grown on glycerol without cyclic AMP cannot utilize mannose when so transferred. These results suggest that the formation of PTSM does not require an exogenous inducer.

scholarly journals Heterologous Production of 6-Deoxyerythronolide B in Escherichia coli through the Wood Werkman Cycle

Metabolites ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 228
Author(s):  
R. Axayacatl Gonzalez-Garcia ◽  
Lars K. Nielsen ◽  
Esteban Marcellin
Keyword(s):  
Escherichia Coli ◽  
Natural Products ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Structural Diversity ◽  
Heterologous Production ◽  
E Coli ◽  
Anticancer Properties ◽  
Defined Media ◽  
Extender Unit

Polyketides are a remarkable class of natural products with diverse functional and structural diversity. The class includes many medicinally important molecules with antiviral, antimicrobial, antifungal and anticancer properties. Native bacterial, fungal and plant hosts are often difficult to cultivate and coax into producing the desired product. As a result, Escherichia coli has been used for the heterologous production of polyketides, with the production of 6-deoxyerythronolide B (6-dEB) being the first example. Current strategies for production in E. coli require feeding of exogenous propionate as a source for the precursors propionyl-CoA and S-methylmalonyl-CoA. Here, we show that heterologous polyketide production is possible from glucose as the sole carbon source. The heterologous expression of eight genes from the Wood-Werkman cycle found in Propionibacteria, in combination with expression of the 6-dEB synthases DEBS1, DEBS2 and DEBS3 resulted in 6-dEB formation from glucose as the sole carbon source. Our results show that the Wood-Werkman cycle provides the required propionyl-CoA and the extender unit S-methylmalonyl-CoA to produce up to 0.81 mg/L of 6-dEB in a chemically defined media.

Evidence against the involvement of adenosine 3′,5′-cyclic monophosphate in glucose inhibition of β-galactosidase induction in Bacillus megaterium

1976 ◽  
Vol 54 (10) ◽  
pp. 854-865 ◽  
Author(s):  
Kwok-Him Yeung ◽  
Gillian Chaloner-Larssgn ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Bacillus Megaterium ◽  
Sole Carbon Source ◽  
The Other ◽  
Cyclic Monophosphate ◽  
Glucose Inhibition ◽  
Significant Rate ◽  
Phosphorylated Compounds ◽  
Grown Culture

When Bacillus megaterium cells are grown on D-galactose as the sole carbon source, the cells actively synthesize β-galactosidase (β-D-galactoside galactohydroIase, EC 3.2.1.23). However, D-galactose, when added to a glucose-grown culture, did not induce β-galactosidase, apparently because of the glucose inhibition of the transport of galactose. On the other hand, when glucose was added to a galactose-grown culture, the transport of galactose continued at a reduced but significant rate, whereas further synthesis of β-galactosidase was halted. Adenosine 3′,5′-cyclic monophosphate (cAMP) or guanosine 3′,5′-cyclic monophosphate (cGMP) did not relieve the glucose inhibition of β-galactosidase synthesis in the preinduced culture. A method which gave a reproducible assay of c[32P]AMP in Escherichia coli did not detect cAMP or cGMP in a B. megaterium culture undergoing β-galactosidase induction, but revealed the extracellular accumulation of two unknown phosphorylated compounds. Cell-free extracts prepared from galactose-grown cells did not catalyze the degradation of cAMP or cGMP.

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