scholarly journals 2-Deoxy-d-galactose, a substrate for the galactose-transport system of Escherichia coli

1977 ◽  
Vol 168 (1) ◽  
pp. 15-22 ◽  
Author(s):  
P J F Henderson ◽  
R A Giddens
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Transport Systems ◽  
Mutual Inhibition ◽  
E Coli ◽  
System 2 ◽  
Galactose Transport ◽  
Proton Uptake ◽  
Inhibition Studies ◽  
Lactose Transport

The following observations showed that 2-deoxy-D-galactose is a useful tool for the isolation and elucidation of the activity of one system for galactose uptake into Escherichia coli. 1. 2-Deoxygalactose, which is not a substrate for growth of E. coli, was transported into strains of the organism induced for galactose transport. 2. By using appropriate mutants it was shown that 2-deoxygalactose is a much better substrate for the galactose-transport system than for the methyl galactoside-transport system. This was confirmed by the results of mutual inhibition studies with substrates of each transport system. 3. The glucose-, arabinose- or lactose-transport systems did not effect significant transport of 2-deoxygalactose. 4. Like other substrates of the galactose-transport system, 2-deoxygalactose promoted effective proton uptake into de-energized suspensions of appropriate E. coli strains. 5. The S183 series of E. coli mutants were found to contain a constitutive galactose-transport system, if 2-deoxygalactose transport is used as one criterion for such activity.

scholarly journals The association of proton movement with galactose transport into subcellular membrane vesicles of Escherichia coli

1983 ◽  
Vol 210 (3) ◽  
pp. 699-705 ◽  
Author(s):  
P Horne ◽  
P J F Henderson
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Direct Evidence ◽  
Membrane Vesicles ◽  
Protonmotive Force ◽  
Ph Values ◽  
Subcellular Membrane ◽  
System 2 ◽  
Galactose Transport ◽  
Proton Movement

1. Subcellular membrane vesicles were prepared from a strain of Escherichia coli constitutive for the GalP galactose-transport system. 2. The addition of substrates of the GalP transport system to vesicle suspensions promoted alkaline pH changes, which provided direct evidence for the coupling of sugar and proton transport. 3. Respiration-energized galactose transport was progressively inhibited at pH values above 6.0, and was abolished by agents that render the membrane permeable to protons. 4. The combined effects of valinomycin, the nigericin-like compound A217 and pH on galactose transport suggested that both delta pH and delta psi components of the protonmotive force contributed to energization of galactose transport. 5. These results substantiate the conclusion that the GalP transport system operates by a chemiosmotic mechanism.

scholarly journals DNA Sequence of a ColV Plasmid and Prevalence of Selected Plasmid-Encoded Virulence Genes among Avian Escherichia coli Strains

2006 ◽  
Vol 188 (2) ◽  
pp. 745-758 ◽  
Author(s):  
Timothy J. Johnson ◽  
Kylie E. Siek ◽  
Sara J. Johnson ◽  
Lisa K. Nolan
Keyword(s):  
Escherichia Coli ◽  
Dna Sequence ◽  
Transport System ◽  
Iron Transport ◽  
Virulence Genes ◽  
Iron Acquisition ◽  
Transport Systems ◽  
E Coli ◽  
Virulence Traits ◽  
Associated Sequences

ABSTRACT ColV plasmids have long been associated with the virulence of Escherichia coli, despite the fact that their namesake trait, ColV production, does not appear to contribute to virulence. Such plasmids or their associated sequences appear to be quite common among avian pathogenic E. coli (APEC) and are strongly linked to the virulence of these organisms. In the present study, a 180-kb ColV plasmid was sequenced and analyzed. This plasmid, pAPEC-O2-ColV, possesses a 93-kb region containing several putative virulence traits, including iss, tsh, and four putative iron acquisition and transport systems. The iron acquisition and transport systems include those encoding aerobactin and salmochelin, the sit ABC iron transport system, and a putative iron transport system novel to APEC, eit. In order to determine the prevalence of the virulence-associated genes within this region among avian E. coli strains, 595 APEC and 199 avian commensal E. coli isolates were examined for genes of this region using PCR. Results indicate that genes contained within a portion of this putative virulence region are highly conserved among APEC and that the genes of this region occur significantly more often in APEC than in avian commensal E. coli. The region of pAPEC-O2-ColV containing genes that are highly prevalent among APEC appears to be a distinguishing trait of APEC strains.

scholarly journals Archaeal Binding Protein-Dependent ABC Transporter: Molecular and Biochemical Analysis of the Trehalose/Maltose Transport System of the Hyperthermophilic Archaeon Thermococcus litoralis

1998 ◽  
Vol 180 (3) ◽  
pp. 680-689 ◽  
Author(s):  
Reinhold Horlacher ◽  
Karina B. Xavier ◽  
Helena Santos ◽  
Jocelyne DiRuggiero ◽  
Marina Kossmann ◽  
...  
Keyword(s):  
Transport System ◽  
Signal Sequence ◽  
Binding Protein ◽  
Inducible Promoter ◽  
Transport Systems ◽  
Thermococcus Litoralis ◽  
Hyperthermophilic Archaeon ◽  
E Coli ◽  
Transmembrane Segments ◽  
Maltose Transport

ABSTRACT We report the cloning and sequencing of a gene cluster encoding a maltose/trehalose transport system of the hyperthermophilic archaeonThermococcus litoralis that is homologous to themalEFG cluster encoding the Escherichia colimaltose transport system. The deduced amino acid sequence of themalE product, the trehalose/maltose-binding protein (TMBP), shows at its N terminus a signal sequence typical for bacterial secreted proteins containing a glyceride lipid modification at the N-terminal cysteine. The T. litoralis malE gene was expressed in E. coli under control of an inducible promoter with and without its natural signal sequence. In addition, in one construct the endogenous signal sequence was replaced by the E. coli MalE signal sequence. The secreted, soluble recombinant protein was analyzed for its binding activity towards trehalose and maltose. The protein bound both sugars at 85°C with aKd of 0.16 μM. Antibodies raised against the recombinant soluble TMBP recognized the detergent-soluble TMBP isolated from T. litoralis membranes as well as the products from all other DNA constructs expressed in E. coli. Transmembrane segments 1 and 2 as well as the N-terminal portion of the large periplasmic loop of the E. coli MalF protein are missing in the T. litoralis MalF. MalG is homologous throughout the entire sequence, including the six transmembrane segments. The conserved EAA loop is present in both proteins. The strong homology found between the components of this archaeal transport system and the bacterial systems is evidence for the evolutionary conservation of the binding protein-dependent ABC transport systems in these two phylogenetic branches.

scholarly journals Escherichia coli type III secretion system 2 (ETT2) is widely distributed in avian pathogenic Escherichia coli isolates from Eastern China

2016 ◽  
Vol 144 (13) ◽  
pp. 2824-2830 ◽  
Author(s):  
S. WANG ◽  
X. LIU ◽  
X. XU ◽  
Y. ZHAO ◽  
D. YANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Bacterial Infections ◽  
Eastern China ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Secretion Systems ◽  
E Coli ◽  
Type Iii ◽  
System 2

SUMMARYPathogens utilize type III secretion systems to deliver effector proteins, which facilitate bacterial infections. The Escherichia coli type III secretion system 2 (ETT2) which plays a crucial role in bacterial virulence, is present in the majority of E. coli strains, although ETT2 has undergone widespread mutational attrition. We investigated the distribution and characteristics of ETT2 in avian pathogenic E. coli (APEC) isolates and identified five different ETT2 isoforms, including intact ETT2, in 57·6% (141/245) of the isolates. The ETT2 locus was present in the predominant APEC serotypes O78, O2 and O1. All of the ETT2 loci in the serotype O78 isolates were degenerate, whereas an intact ETT2 locus was mostly present in O1 and O2 serotype strains, which belong to phylogenetic groups B2 and D, respectively. Interestingly, a putative second type III secretion-associated locus (eip locus) was present only in the isolates with an intact ETT2. Moreover, ETT2 was more widely distributed in APEC isolates and exhibited more isoforms compared to ETT2 in human extraintestinal pathogenic E. coli, suggesting that APEC might be a potential risk to human health. However, there was no distinct correlation between ETT2 and other virulence factors in APEC.

scholarly journals The Hydantoin Transport Protein from Microbacterium liquefaciens

2006 ◽  
Vol 188 (9) ◽  
pp. 3329-3336 ◽  
Author(s):  
Shun'ichi Suzuki ◽  
Peter J. F. Henderson
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Membrane Fraction ◽  
Transport Protein ◽  
Host Strain ◽  
Expression Plasmid ◽  
Ph Optimum ◽  
Inner Membrane ◽  
E Coli ◽  
Micromolar Range

ABSTRACT The gene hyuP from Microbacterium liquefaciens AJ 3912 with an added His6 tag was cloned into the expression plasmid pTTQ18 in an Escherichia coli host strain. The transformed E. coli showed transport of radioisotope-labeled 5-substituted hydantoins with apparent Km values in the micromolar range. This activity exhibited a pH optimum of 6.6 and was inhibited by dinitrophenol, indicating the requirement of energy for the transport system. 5-Indolyl methyl hydantoin and 5-benzyl hydantoin were the preferred substrates, with selectivity for a hydrophobic substituent in position 5 of hydantoin and for the l isomer over the d isomer. Hydantoins with less hydrophobic substituents, cytosine, thiamine, uracil, allantoin, adenine, and guanine, were not effective ligands. The His-tagged hydantoin transport protein was located in the inner membrane fraction, from which it was solubilized and purified and its identity was authenticated.

scholarly journals Specific Secretion of Active Single-Chain Fv Antibodies into the Supernatants of Escherichia coliCultures by Use of the Hemolysin System

2000 ◽  
Vol 66 (11) ◽  
pp. 5024-5029 ◽  
Author(s):  
Luis A. Fernández ◽  
Isabel Sola ◽  
Luis Enjuanes ◽  
Víctor de Lorenzo
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Culture Media ◽  
Single Chain ◽  
Extracellular Medium ◽  
Simple Method ◽  
E Coli ◽  
Single Chain Fv ◽  
Bacterial Cytoplasm ◽  
Culture Supernatants

ABSTRACT A simple method for the nontoxic, specific, and efficient secretion of active single-chain Fv antibodies (scFvs) into the supernatants ofEscherichia coli cultures is reported. The method is based on the well-characterized hemolysin transport system (Hly) of E. coli that specifically secretes the target protein from the bacterial cytoplasm into the extracellular medium without a periplasmic intermediate. The culture media that accumulate these Hly-secreted scFv's can be used in a variety of immunoassays without purification. In addition, these culture supernatants are stable over long periods of time and can be handled basically as immune sera.

scholarly journals Transport of galactose, glucose and their molecular analogues by Escherichia coli K12

1977 ◽  
Vol 162 (2) ◽  
pp. 309-320 ◽  
Author(s):  
P J F Henderson ◽  
R A Giddens ◽  
M C Jones-Mortimer
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Proton Transport ◽  
Regulatory Mechanism ◽  
Transport Systems ◽  
British Library ◽  
Transport Activity ◽  
Phosphotransferase System ◽  
Escherichia Coli K12 ◽  
Specific Transport System

1. Strains of Escherichia coli K12 were made that are unable to assimilate glucose by the phosphotransferase system, since they lack the glucose-specific components specified by the genes ptsG and ptsM. 2. Derivative organisms lacking the methyl galactoside or galactose-specific transport system were examined for their ability to transport galactose, d-fucose, methyl beta-D-galactoside, glucose, 2-deoxy-D-glucose and methyl alpha-D-glucoside. 3. Galactose, glucose and to a lesser extent fucose are substrates for both transport systems. 4. 2-Deoxyglucose is transported on the galactose-specific but not the methyl galactoside system. 5. The ability of sugars to elicit anaerobic proton transport is associated with the galactose-specific, but not with the methyl galactoside transport activity. Hence a chemiosmotic mechanism of energization is likely to apply to the former but not to the latter. Alternatively the methyl galactoside system may be switched off under certain conditions, which would indicate a novel regulatory mechanism. 6. Details of the procedure for the derivation of strains may be obtained from the authors, and have been deposited as Supplementary Publication SUP 50074 (8 pages at the) British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977), 161,1.

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