scholarly journals Haemophilus influenzae Rd Lacks a Stringently Conserved Fatty Acid Biosynthetic Enzyme and Thermal Control of Membrane Lipid Composition

2003 ◽  
Vol 185 (16) ◽  
pp. 4930-4937 ◽  
Author(s):  
Haihong Wang ◽  
John E. Cronan
Keyword(s):  
Fatty Acid ◽  
Haemophilus Influenzae ◽  
Growth Temperature ◽  
Acyl Carrier Protein ◽  
Thermal Control ◽  
Membrane Lipid ◽  
Membrane Phospholipids ◽  
E Coli ◽  
K 12

ABSTRACT The organization of the fatty acid synthetic genes of Haemophilus influenzae Rd is remarkably similar to that of the paradigm organism, Escherichia coli K-12, except that no homologue of the E. coli fabF gene is present. This finding is unexpected, since fabF is very widely distributed among bacteria and is thought to be the generic 3-ketoacyl-acyl carrier protein (ACP) synthase active on long-chain-length substrates. However, H. influenzae Rd contains a homologue of the E. coli fabB gene, which encodes a 3-ketoacyl-ACP synthase required for unsaturated fatty acid synthesis, and it seemed possible that the H. influenzae FabB homologue might have acquired the functions of FabF. E. coli mutants lacking fabF function are unable to regulate the compositions of membrane phospholipids in response to growth temperature. We report in vivo evidence that the enzyme encoded by the H. influenzae fabB gene has properties essentially identical to those of E. coli FabB and lacks FabF activity. Therefore, H. influenzae grows without FabF function. Moreover, as predicted from studies of the E. coli fabF mutants, H. influenzae is unable to change the fatty acid compositions of its membrane phospholipids with growth temperature. We also demonstrate that the fabB gene of Vibrio cholerae El Tor N16961 does not contain a frameshift mutation as was previously reported.

scholarly journals Structure of a SLC26 Anion Transporter STAS Domain in Complex with Acyl Carrier Protein: Implications for E. coli YchM in Fatty Acid Metabolism

Structure ◽  
2010 ◽  
Vol 18 (11) ◽  
pp. 1450-1462 ◽  
Author(s):  
Mohan Babu ◽  
Jack F. Greenblatt ◽  
Andrew Emili ◽  
Natalie C.J. Strynadka ◽  
Reinhart A.F. Reithmeier ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
E Coli ◽  
Anion Transporter ◽  
Stas Domain

scholarly journals Dynamic modulation of mitochondrial membrane physical properties and ATPase activity by diet lipid

1981 ◽  
Vol 198 (1) ◽  
pp. 167-175 ◽  
Author(s):  
S M Innis ◽  
M T Clandinin
Keyword(s):  
Fatty Acid ◽  
Rapeseed Oil ◽  
Membrane Lipid ◽  
Dietary Lipid ◽  
Soya Bean ◽  
The Body ◽  
Kinetic Properties ◽  
Mitochondrial Atpase ◽  
Lipid Environment

A longitudinal cross-over feeding design was used to investigate the relationship of dietary lipid composition to the membrane lipid environment and activity of mitochondrial ATPase in vivo. Rats were fed a polyunsaturated fatty-acid-rich oil (soya-bean oil) for 12 days, crossed-over to a monounsaturated fatty-acid-rich oil (rapeseed oil) for the next 11 days, then returned to soya-bean oil for 11 more days. Additional rats were fed either soya-bean oil or rapeseed oil throughout. Rats fed rapeseed oil had lower rates of ATPase-catalysed ATP/[32P]Pi exchange than rats fed soya-bean oil. Arrhenius plots showed higher transition temperature (Tt) and activation energy (Ea) for rats fed rapeseed oil. Switching from soya-bean oil to rapeseed oil was dynamically followed by changes in the thermotropic and kinetic properties of the mitochondrial ATPase exchange reaction. Returning to soya-bean oil reversed these changes. The rapid and reversible modulation of Tt caused by a change of the type of fat ingested suggests that membrane physicochemical properties are not under rigid intrinsic control but are continually modified by the profile of exogenously derived fatty acids. The studies suggest that in vivo the activity of mitochondrial ATPase is in part determined by dietary lipid via its influence on the microenvironment of the enzyme. The rapidity and ready reversibility of changes observed for this subcellular-membrane-bound enzyme suggest that dietary fatty-acid balance may be an important determinant of other membrane functions in the body.

Chromosomal Integration of Heterologous DNA in Escherichia coli with Precise Removal of Markers and Replicons Used during Construction

1999 ◽  
Vol 181 (22) ◽  
pp. 7143-7148 ◽  
Author(s):  
F. Martinez-Morales ◽  
A. C. Borges ◽  
A. Martinez ◽  
K. T. Shanmugam ◽  
L. O. Ingram
Keyword(s):  
Escherichia Coli ◽  
Helper Plasmid ◽  
Flp Recombinase ◽  
E Coli ◽  
Homologous Fragment ◽  
Genes Encoding ◽  
Dna Insertion ◽  
K 12 ◽  
Multiple Cloning Sites

ABSTRACT A set of vectors which facilitates the sequential integration of new functions into the Escherichia coli chromosome by homologous recombination has been developed. These vectors are based on plasmids described by Posfai et al. (J. Bacteriol. 179:4426–4428, 1997) which contain conditional replicons (pSC101 or R6K), a choice of three selectable markers (ampicillin, chloramphenicol, or kanamycin), and a single FRT site. The modified vectors contain twoFRT sites which bracket a modified multiple cloning region for DNA insertion. After integration, a helper plasmid expressing the flippase (FLP) recombinase allows precise in vivo excision of the replicon and the marker used for selection. Sites are also available for temporary insertion of additional functions which can be subsequently deleted with the replicon. Only the DNA inserted into the multiple cloning sites (passenger genes and homologous fragment for targeting) and a single FRT site (68 bp) remain in the chromosome after excision. The utility of these vectors was demonstrated by integrating Zymomonas mobilis genes encoding the ethanol pathway behind the native chromosomaladhE gene in strains of E. coli K-12 andE. coli B. With these vectors, a single antibiotic selection system can be used repeatedly for the successive improvement of E. coli strains with precise deletion of extraneous genes used during construction.

Phosphorylierung von Methylthio-β.ᴅ-galaktosid in E. coli

1968 ◽  
Vol 23 (9) ◽  
pp. 1219-1221 ◽  
Author(s):  
E. Lodemann ◽  
S. Iskrić ◽  
C. Altaner ◽  
A. Wacker
Keyword(s):  
E Coli ◽  
K 12

Methylthio-β.ᴅ-galaktosid wird in E. coli K 12, sowie in den Mutanten ML 3 und ML 308 in vivo zu einem geringen Teil in einen Phosphorsäureester, wahrscheinlich das 6-Phosphat (TMG-P) umgewandelt. TMG-P wird von E. coli K 12 aufgenommen, wirkt jedoch nicht als Induktor des Lactose-Operons. Zellfreie Extrakte aus E. coli K 12 geben die gleiche Reaktion, wobei die in vitro-Reaktion durch anorganisches Phosphat und Phosphoenolpyruvat stimuliert wird.

scholarly journals Regulatory Role of PlaR (YiaJ) for Plant Utilization in Escherichia coli K-12

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tomohiro Shimada ◽  
Yui Yokoyama ◽  
Takumi Anzai ◽  
Kaneyoshi Yamamoto ◽  
Akira Ishihama
Keyword(s):  
Escherichia Coli ◽  
Genetic System ◽  
Regulatory Role ◽  
E Coli ◽  
Warm Blooded Animal ◽  
Plant Utilization ◽  
K 12

AbstractOutside a warm-blooded animal host, the enterobacterium Escherichia coli K-12 is also able to grow and survive in stressful nature. The major organic substance in nature is plant, but the genetic system of E. coli how to utilize plant-derived materials as nutrients is poorly understood. Here we describe the set of regulatory targets for uncharacterized IclR-family transcription factor YiaJ on the E. coli genome, using gSELEX screening system. Among a total of 18 high-affinity binding targets of YiaJ, the major regulatory target was identified to be the yiaLMNOPQRS operon for utilization of ascorbate from fruits and galacturonate from plant pectin. The targets of YiaJ also include the genes involved in the utilization for other plant-derived materials as nutrients such as fructose, sorbitol, glycerol and fructoselysine. Detailed in vitro and in vivo analyses suggest that L-ascorbate and α-D-galacturonate are the effector ligands for regulation of YiaJ function. These findings altogether indicate that YiaJ plays a major regulatory role in expression of a set of the genes for the utilization of plant-derived materials as nutrients for survival. PlaR was also suggested to play protecting roles of E. coli under stressful environments in nature, including the formation of biofilm. We then propose renaming YiaJ to PlaR (regulator of plant utilization).

Silver and hydrogen peroxide as potential drinking water disinfectants: their bactericidal effects and possible modes of action

1997 ◽  
Vol 35 (11-12) ◽  
pp. 87-93 ◽  
Author(s):  
R. Pedahzur ◽  
H. I. Shuval ◽  
S. Ulitzur
Keyword(s):  
Hydrogen Peroxide ◽  
Synergistic Effect ◽  
Vibrio Fischeri ◽  
E Coli ◽  
Bactericidal Effects ◽  
Synergistic Induction ◽  
Response Systems ◽  
K 12 ◽  
Consequent Increase

Silver and hydrogen peroxide (HP) acted synergistically on the viability of E. coli K-12. In certain concentration ranges the synergistic effect amounted to about 3 logs. Toxicity process kinetics were determined by following the decrease in luminescence of a highly luminescent recombinant E. coli harbouring a plasmid carrying the whole lux system of Vibrio fischeri. As in the viability studies, silver and HP also showed a synergistic effect on in vivo luminescence, which amounted to a 2 log increase in toxicity. A similar phenomenon was found for silver and certain metal ions, including Cu2+, Ni2+, Zn2+ and Cd2+, where toxicity increased by a factor of 10 in the presence of sub-inhibitory concentrations of silver. To monitor the expression of different stress response systems in treated cells, we have used E. coli carrying fusions of the lux system to promoters of different stress-controlling genes. Of the fusions tested, HP substantially increased the activity of recA, katG, micF, grpE, lon, and dnaK. Silver exerted a mild effect acting only on grpE and lon promoters. When in combination, a synergistic induction of the dnaK fusion and a slightly additive effect on grpE fusion were recorded. It appears that the combined toxic effect of silver and HP may be related with damage to cellular proteins. Nevertheless, the involvement of other cellular moieties can not be ruled out. The possibility that the synergistic effect is related to chemical interactions between silver and HP and the consequent increase in their toxicity is discussed.

scholarly journals Adaptation in a Mouse Colony Monoassociated with Escherichia coli K-12 for More than 1,000 Days

2010 ◽  
Vol 76 (14) ◽  
pp. 4655-4663 ◽  
Author(s):  
Sean M. Lee ◽  
Aaron Wyse ◽  
Aaron Lesher ◽  
Mary Lou Everett ◽  
Linda Lou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rates ◽  
Bacterial Species ◽  
Intestinal Flora ◽  
Average Density ◽  
Host Bacterium ◽  
E Coli ◽  
K 12

ABSTRACT Although mice associated with a single bacterial species have been used to provide a simple model for analysis of host-bacteria relationships, bacteria have been shown to display adaptability when grown in a variety of novel environments. In this study, changes associated with the host-bacterium relationship in mice monoassociated with Escherichia coli K-12 over a period of 1,031 days were evaluated. After 80 days, phenotypic diversification of E. coli was observed, with the colonizing bacteria having a broader distribution of growth rates in the laboratory than the parent E. coli. After 1,031 days, which included three generations of mice and an estimated 20,000 generations of E. coli, the initially homogeneous bacteria colonizing the mice had evolved to have widely different growth rates on agar, a potential decrease in tendency for spontaneous lysis in vivo, and an increased tendency for spontaneous lysis in vitro. Importantly, mice at the end of the experiment were colonized at an average density of bacteria that was more than 3-fold greater than mice colonized on day 80. Evaluation of selected isolates on day 1,031 revealed unique restriction endonuclease patterns and differences between isolates in expression of more than 10% of the proteins identified by two-dimensional electrophoresis, suggesting complex changes underlying the evolution of diversity during the experiment. These results suggest that monoassociated mice might be used as a tool for characterizing niches occupied by the intestinal flora and potentially as a method of targeting the evolution of bacteria for applications in biotechnology.

Triclosan Resistance in Francisella tularensis: A Site-Directed Mutagenesis Study of the FabI Enzyme

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
N. Silas ◽  
R. Demissie ◽  
L.W.M. Fung
Keyword(s):  
Fatty Acid ◽  
Francisella Tularensis ◽  
Bacterial Resistance ◽  
Fatty Acid Biosynthesis ◽  
Acyl Carrier Protein ◽  
Enzymatic Reaction ◽  
Site Directed Mutagenesis ◽  
E Coli ◽  
Bacterial Fatty Acid ◽  
Triclosan Resistance

An NADH-dependent enoyl-acyl carrier protein reductase, FabI, catalyzes the final step of bacterial fatty acid biosynthesis, reducing the double bond of trans-2-enoyl-ACP to a single bond forming acyl-ACP. Given its importance in bacterial fatty acid synthesis, FabI has become a recognized drug target. Triclosan, a diphenyl ether, targets the FabI, inhibits its activity, and stops bacterial growth. However, as a consequence of triclosan's popularity, and thus its overuse, bacterial resistance to triclosan has been reported. The mutation G93V in Escherichia coli (E. coli) FabI allows E. coli to resist the action of triclosan. We have identified the equivalent residue of G93 in Francisella tularensis FabI (ftFabI) as A92, and prepared a mutant A92V. E. coli cells, transformed with a plasmid containing the ftFabI-A92V gene, were grown, and the gene was overexpressed. From two growths (6 G of cells), 62 mG of protein, with a histidine tag, at a purity of 85% were obtained. Enzymatic activity was assayed by monitoring the absorbance of NADH at 340 nm. In the presence of triclosan, the wild-type protein was almost completely inhibited after NADH was converted to NAD$^+$ in the enzymatic reaction; however the A92V mutant exhibited similar activity with and without triclosan, demonstrating that triclosan resistance may also develop in Francisella tularensis.

scholarly journals In Vitro Inhibition of the Mycobacterium tuberculosis β-Ketoacyl-Acyl Carrier Protein Reductase MabA by Isoniazid

2004 ◽  
Vol 48 (1) ◽  
pp. 242-249 ◽  
Author(s):  
Stéphanie Ducasse-Cabanot ◽  
Martin Cohen-Gonsaud ◽  
Hedia Marrakchi ◽  
Michel Nguyen ◽  
Didier Zerbib ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Dynamic Equilibrium ◽  
Acyl Carrier Protein ◽  
Multidrug Resistant ◽  
Carrier Protein ◽  
Ligand Complex ◽  
Fas Ii

ABSTRACT The first-line specific antituberculous drug isoniazid inhibits the fatty acid elongation system (FAS) FAS-II involved in the biosynthesis of mycolic acids, which are major lipids of the mycobacterial envelope. The MabA protein that catalyzes the second step of the FAS-II elongation cycle is structurally and functionally related to the in vivo target of isoniazid, InhA, an NADH-dependent enoyl-acyl carrier protein reductase. The present work shows that the NADPH-dependent β-ketoacyl reduction activity of MabA is efficiently inhibited by isoniazid in vitro by a mechanism similar to that by which isoniazid inhibits InhA activity. It involves the formation of a covalent adduct between MnIII-activated isoniazid and the MabA cofactor. Liquid chromatography-mass spectrometry analyses revealed that the isonicotinoyl-NADP adduct has multiple chemical forms in dynamic equilibrium. Both kinetic experiments with isolated forms and purification of the enzyme-ligand complex strongly suggested that the molecules active against MabA activity are the oxidized derivative and a major cyclic form. Spectrofluorimetry showed that the adduct binds to the MabA active site. Modeling of the MabA-adduct complex predicted an interaction between the isonicotinoyl moiety of the inhibitor and Tyr185. This hypothesis was supported by the fact that a higher 50% inhibitory concentration of the adduct was measured for MabA Y185L than for the wild-type enzyme, while both proteins presented similar affinities for NADP+. The crystal structure of MabA Y185L that was solved showed that the substitution of Tyr185 induced no significant conformational change. The description of the first inhibitor of the β-ketoacyl reduction step of fatty acid biosynthesis should help in the design of new antituberculous drugs efficient against multidrug-resistant tubercle bacilli.

scholarly journals Monounsaturated Fatty Acids Are Substrates for Aldehyde Generation in Tellurite-ExposedEscherichia coli

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Gonzalo A. Pradenas ◽  
Waldo A. Díaz-Vásquez ◽  
José M. Pérez-Donoso ◽  
Claudio C. Vásquez
Keyword(s):  
Oxidative Stress ◽  
Fatty Acid ◽  
Bacterial Resistance ◽  
Monounsaturated Fatty Acids ◽  
Membrane Lipid ◽  
Fatty Acid Profiles ◽  
Wild Type ◽  
E Coli ◽  
Membrane Oxidation ◽  
Cellular Components

Reactive oxygen species (ROS) damage macromolecules and cellular components in nearly all kinds of cells and often generate toxic intracellular byproducts. In this work, aldehyde generation derived from theEscherichia colimembrane oxidation as well as membrane fatty acid profiles, protein oxidation, and bacterial resistance to oxidative stress elicitors was evaluated. Studies included wild-type cells as well as cells exhibiting a modulated monounsaturated fatty acid (MUFA) ratio. The hydroxyaldehyde 4-hydroxy 2-nonenal was found to be most likely produced byE. coli, whose levels are dependent upon exposure to oxidative stress elicitors. Aldehyde amounts and markers of oxidative damage decreased upon exposure toE. colicontaining low MUFA ratios, which was paralleled by a concomitant increase in resistance to ROS-generating compounds. MUFAs ratio, lipid peroxidation, and aldehyde generation were found to be directly related; that is, the lower the MUFAs ratio, the lower the peroxide and aldehyde generation levels. These results provide additional evidence about MUFAs being targets for membrane lipid oxidation and their relevance in aldehyde generation.

Sign in / Sign up

Export Citation Format

Share Document