scholarly journals Participation of Acyl-Coenzyme A Synthetase FadD4 of Pseudomonas aeruginosa PAO1 in Acyclic Terpene/Fatty Acid Assimilation and Virulence by Lipid A Modification

2021 ◽  
Vol 12 ◽  
Author(s):  
Lorena Martínez-Alcantar ◽  
Gabriela Orozco ◽  
Alma Laura Díaz-Pérez ◽  
Javier Villegas ◽  
Homero Reyes-De la Cruz ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fatty Acid ◽  
Lipid A ◽  
Acid Methyl Ester ◽  
Genetic Redundancy ◽  
Single Mutant ◽  
Fame Analysis ◽  
Metabolic Versatility ◽  
Acyl Coenzyme A

The pathogenic bacterium Pseudomonas aeruginosa possesses high metabolic versatility, with its effectiveness to cause infections likely due to its well-regulated genetic content. P. aeruginosa PAO1 has at least six fadD paralogous genes, which have been implicated in fatty acid (FA) degradation and pathogenicity. In this study, we used mutagenesis and a functional approach in P. aeruginosa PAO1 to determine the roles of the fadD4 gene in acyclic terpene (AT) and FA assimilation and on pathogenicity. The results indicate that fadD4 encodes a terpenoyl-CoA synthetase utilized for AT and FA assimilation. Additionally, mutations in fadD paralogs led to the modification of the quorum-sensing las/rhl systems, as well as the content of virulence factors pyocyanin, biofilm, rhamnolipids, lipopolysaccharides (LPS), and polyhydroxyalkanoates. In a Caenorhabditis elegans in vivo pathogenicity model, culture supernatants from the 24-h-grown fadD4 single mutant increased lethality compared to the PAO1 wild-type (WT) strain; however, the double mutants fadD1/fadD2, fadD1/fadD4, and fadD2/fadD4 and single mutant fadD2 increased worm survival. A correlation analysis indicated an interaction between worm death by the PAO1 strain, the fadD4 mutation, and the virulence factor LPS. Fatty acid methyl ester (FAME) analysis of LPS revealed that a proportion of the LPS and FA on lipid A were modified by the fadD4 mutation, suggesting that FadD4 is also involved in the synthesis/degradation and modification of the lipid A component of LPS. LPS isolated from the fadD4 mutant and double mutants fadD1/fadD4 and fadD2/fadD4 showed a differential behavior to induce an increase in body temperature in rats injected with LPS compared to the WT strain or from the fadD1 and fadD2 mutants. In agreement, LPS isolated from the fadD4 mutant and double mutants fadD1/fadD2 and fadD2/fadD4 increased the induction of IL-8 in rat sera, but IL1-β cytokine levels decreased in the double mutants fadD1/fadD2 and fadD1/fadD4. The results indicate that the fadD genes are implicated in the degree of pathogenicity of P. aeruginosa PAO1 induced by LPS-lipid A, suggesting that FadD4 contributes to the removal of acyl-linked FA from LPS, rendering modification in its immunogenic response associated to Toll-like receptor TLR4. The genetic redundancy of fadD is important for bacterial adaptability and pathogenicity over the host.

Differentiation between Candida dubliniensis andCandida albicans by Fatty Acid Methyl Ester Analysis Using Gas-Liquid Chromatography

2000 ◽  
Vol 38 (10) ◽  
pp. 3696-3704 ◽  
Author(s):  
Heidrun Peltroche-Llacsahuanga ◽  
Silke Schmidt ◽  
Michael Seibold ◽  
Rudolf Lütticken ◽  
Gerhard Haase
Keyword(s):  
Liquid Chromatography ◽  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Acid Methyl Ester ◽  
Candida Dubliniensis ◽  
Identification System ◽  
Gas Liquid Chromatography ◽  
Fame Analysis ◽  
Acid Methyl

Candida dubliniensis is often found in mixed culture with C. albicans, but its recognition is hampered as the color of its colonies in primary culture on CHROMagar Candida varies. Furthermore, definite identification of C. dubliniensis is difficult to achieve, time-consuming, and expensive. Therefore, a method to discriminate between these two closely related yeast species by fatty acid methyl ester (FAME) analysis using gas-liquid chromatography (Sherlock Microbial Identification System [MIS]; MIDI, Inc., Newark, Del.) was developed. Although the chromatograms of these two species revealed no obvious differences when applying FAME analysis, a new library (CADLIB) was successfully created using Sherlock Library Generation Software (MIDI). The amount and frequency of FAME was analyzed using library training files (n = 10 for each species), preferentially those comprising reference strains. For testing the performance of the CADLIB, clinical isolates genetically assigned to the respective species (C. albicans, n = 32; C. dubliniensis, n = 28) were chromatographically analyzed. For each isolate tested, MIS computed a similarity index (SI) indicating a hierarchy of possible strain fits. When using the newly created library CADLIB, the SIs for C. albicans andC. dubliniensis ranged from 0.11 to 0.96 and 0.53 to 0.93 (for all but one), respectively. Only three isolates of C. albicans (9.4%) were misidentified as C. dubliniensis, whereas all isolates of C. dubliniensiswere correctly identified. Resulting differentiation accuracy was 90.6% for C. albicans and 100% for C. dubliniensis. Cluster analysis and principal component analysis of the resulting FAME profiles showed two clearly distinguishable clusters matching up with two assigned species for the strains tested. Thus, the created library proved to be well suited to discriminate between these two species.

scholarly journals Pseudomonas aeruginosa PqsA Is an Anthranilate-Coenzyme A Ligase

2007 ◽  
Vol 190 (4) ◽  
pp. 1247-1255 ◽  
Author(s):  
James P. Coleman ◽  
L. Lynn Hudson ◽  
Susan L. McKnight ◽  
John M. Farrow ◽  
M. Worth Calfee ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Coenzyme A ◽  
Intercellular Signaling ◽  
Signaling Systems ◽  
Coa Ligase ◽  
Coenzyme A Ligase ◽  
Opportunistic Human Pathogen ◽  
Acyl Coenzyme A

ABSTRACT Pseudomonas aeruginosa is an opportunistic human pathogen which relies on several intercellular signaling systems for optimum population density-dependent regulation of virulence genes. The Pseudomonas quinolone signal (PQS) is a 3-hydroxy-4-quinolone with a 2-alkyl substitution which is synthesized by the condensation of anthranilic acid with a 3-keto-fatty acid. The pqsABCDE operon has been identified as being necessary for PQS production, and the pqsA gene encodes a predicted protein with homology to acyl coenzyme A (acyl-CoA) ligases. In order to elucidate the first step of the 4-quinolone synthesis pathway in P. aeruginosa, we have characterized the function of the pqsA gene product. Extracts prepared from Escherichia coli expressing PqsA were shown to catalyze the formation of anthraniloyl-CoA from anthranilate, ATP, and CoA. The PqsA protein was purified as a recombinant His-tagged polypeptide, and this protein was shown to have anthranilate-CoA ligase activity. The enzyme was active on a variety of aromatic substrates, including benzoate and chloro and fluoro derivatives of anthranilate. Inhibition of PQS formation in vivo was observed for the chloro- and fluoroanthranilate derivatives, as well as for several analogs which were not PqsA enzymatic substrates. These results indicate that the PqsA protein is responsible for priming anthranilate for entry into the PQS biosynthetic pathway and that this enzyme may serve as a useful in vitro indicator for potential agents to disrupt quinolone signaling in P. aeruginosa.

scholarly journals Biological Characterization of Endotoxins Released from Antibiotic-Treated Pseudomonas aeruginosa and Escherichia coli

1998 ◽  
Vol 42 (5) ◽  
pp. 1015-1021 ◽  
Author(s):  
Teruo Kirikae ◽  
Fumiko Kirikae ◽  
Shinji Saito ◽  
Kaoru Tominaga ◽  
Hirohi Tamura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Biological Activities ◽  
Polymyxin B ◽  
Mitogen Activated Protein Kinase ◽  
No Production ◽  
Endotoxic Activity

ABSTRACT The supernatants taken from Pseudomonas aeruginosa andEscherichia coli cultures in human sera or chemically defined M9 medium in the presence of ceftazidime (CAZ) contained high levels of endotoxin, while those taken from the same cultures in the presence of imipenem (IPM) yielded a very low level of endotoxin. The biological activities of endotoxin in the supernatants were compared with those of phenol water-extracted lipopolysaccharide (LPS). The endotoxin released from the organisms as a result of CAZ treatment (CAZ-released endotoxin) contained a large amount of protein. The protein, however, lacked endotoxic activity, since the endotoxin did not show any in vivo toxic effects in LPS-hyporesponsive C3H/HeJ mice sensitized with d-(+)-galactosamine (GalN) or any activation of C3H/HeJ mouse macrophages in vitro. The activities of CAZ- and IPM-released endotoxin (as assessed by a chromogenicLimulus test) were fundamentally the same as those ofP. aeruginosa LPS, since their regression lines were parallel. The CAZ-released endotoxin was similar to purified LPS with respect to the following biological activities in LPS-responsive C3H/HeN mice and LPS-hyporesponsive C3H/HeJ mice: lethal toxicity in GalN-sensitized mice, in vitro induction of tumor necrosis factor- and NO production by macrophages, and mitogen-activated protein kinase activation in macrophages. The macrophage activation by CAZ-released endotoxin as well as LPS was mainly dependent on the presence of serum factor and CD14 antigen. Polymyxin B blocked the activity. These findings indicate that the endotoxic activity of CAZ-released endotoxin is due primarily to LPS (lipid A).

scholarly journals Involvement of the Escherichia coli O157:H7(pO157) ecf Operon and Lipid A Myristoyl Transferase Activity in Bacterial Survival in the Bovine Gastrointestinal Tract and Bacterial Persistence in Farm Water Troughs

2005 ◽  
Vol 73 (4) ◽  
pp. 2367-2378 ◽  
Author(s):  
Jang W. Yoon ◽  
Ji Youn Lim ◽  
Yong H. Park ◽  
Carolyn J. Hovde
Keyword(s):  
Escherichia Coli ◽  
Membrane Structure ◽  
Lipid A ◽  
Transferase Activity ◽  
Bacterial Membrane ◽  
Dna Curvature ◽  
Bacterial Survival ◽  
Genetic Redundancy ◽  
E Coli

ABSTRACT Escherichia coli O157:H7 is an important food-borne pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome in humans. Recently, we reported that the pO157 ecf (E. coli attaching and effacing gene-positive conserved fragments) operon is thermoregulated by an intrinsically curved DNA and contains the genes for bacterial surface-associated proteins, including a second copy of lipid A myristoyl transferase, whose chromosomal copy is the lpxM gene product. E. coli O157:H7 survives and persists well in diverse environments from the human and bovine gastrointestinal tracts (GIT) to nutrient-dilute farm water troughs. Transcriptional regulation of the ecf operon by intrinsic DNA curvature and the genetic redundancy of lpxM that is associated with lipid A modification led us to hypothesize that the pO157 ecf operon and lpxM are associated with bacterial survival and persistence in various in vivo and ex vivo environments by optimizing bacterial membrane structure and/or integrity. To test this hypothesis, three isogenic ecf operon and/or lpxM deletion mutants of E. coli O157:H7 ATCC 43894 were constructed and analyzed in vitro and in vivo. The results showed that a double mutant carrying deletions in the ecf and lpxM genes had an altered lipid A structure and membrane fatty acid composition, did not survive passage through the bovine GIT, did not persist well in farm water troughs, had increased susceptibility to a broad spectrum of antibiotics and detergents, and had impaired motility. Electron microscopic analyses showed gross changes in bacterial membrane structure.

scholarly journals Reduction of Detrimental Effect of Soybean Oil in-vivo Using Watermelon White Rind Extract

2019 ◽  
pp. 1-6
Author(s):  
Hanan M. El-Ghandour
Keyword(s):  
Fatty Acid ◽  
Linoleic Acid ◽  
Methyl Ester ◽  
Soybean Oil ◽  
Aqueous Extract ◽  
Calcium Level ◽  
Acid Methyl Ester ◽  
Negative Control ◽  
Acid Methyl

Aim: To study the effect of white rind extract on decreasing soybean oil impact on calcium and phosphorous blood levels in vivo. Method: Dried watermelon white rind was directed to mycotoxin and elemental determinations to assure its safe usage. Soybean oil was subjected to fatty acid and GC-MS analysis. Biological experiment was conducted using male albino rats fed diet prepared by soybean oil and supplied with aqueous watermelon white rind extract for two months’ interval period. At the end of the experiment, the calcium and phosphorus in blood were determined. Results: The rind was free from aflatoxin and ochratoxin. Watermelon white rind aqueous extract contained iron, copper, potassium, chromium and selenium at concentration ranges of 3.4, 0.53, 45.51, 0.0142 and 0.0985 ppm, respectively. Soybean oil had free fatty acid, peroxide value, iodine number and anisidine value of 0.43%, 13.62 meq O2/Kg, 132 and 0.7, respectively. GC-MS analysis of soy oil ascertained the presence of twenty-four compounds: linoleic acid, methyl ester (25.27%), monensin (15.75%), elaidic acid (9.24%), nonadecanoic acid, methyl ester (7.04%), cis-13-eicosenoic acid (4.92%), cis-vaccenic acid (4.68%), linoleic acid (4.67%), palmitoleic acid (4.46%), 9-tetradecenal (4.42%) and cysteine (4.18%)were the most predominant. Fatty acid profile of the oil showed that the ratio of saturated fatty acid to unsaturated fatty acids was 1:5. Conclusion: Rats fed diet prepared by soybean oil had a decreased calcium level in comparison with negative control (p<0.05). Supplementation with watermelon white rind aqueous extract rendered calcium level to normal status as negative control. Phosphorus level wasn’t affected by soya oil.  

scholarly journals Quorum Sensing Is Accompanied by Global Metabolic Changes in the Opportunistic Human Pathogen Pseudomonas aeruginosa

2015 ◽  
Vol 197 (12) ◽  
pp. 2072-2082 ◽  
Author(s):  
Peter W. Davenport ◽  
Julian L. Griffin ◽  
Martin Welch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fatty Acid ◽  
Quorum Sensing ◽  
Acid Methyl Ester ◽  
Metabolic Changes ◽  
Human Pathogen ◽  
Wild Type ◽  
Content Type ◽  
Ecological Fitness ◽  
Opportunistic Human Pathogen

ABSTRACTPseudomonas aeruginosausesN-acyl-homoserine lactone (AHL)-dependent quorum sensing (QS) systems to control the expression of secreted effectors. These effectors can be crucial to the ecological fitness of the bacterium, playing roles in nutrient acquisition, microbial competition, and virulence. In this study, we investigated the metabolic consequences of AHL-dependent QS by monitoring the metabolic profile(s) of alasI rhlIdouble mutant (unable to make QS signaling molecules) and its wild-type progenitor as they progressed through the growth curve. Analysis of culture supernatants by1H-nuclear magnetic resonance (1H-NMR) spectroscopy revealed that at the point where AHL concentrations peaked in the wild type, the metabolic footprints (i.e., extracellular metabolites) of the wild-type andlasI rhlImutant diverged. Subsequent gas chromatography-mass spectrometry (GC-MS)-based analysis of the intracellular metabolome revealed QS-dependent perturbations in around one-third of all identified metabolites, including altered concentrations of tricarboxylic acid (TCA) cycle intermediates, amino acids, and fatty acids. Further targeted fatty acid methyl ester (FAME) GC-MS-based profiling of the cellular total fatty acid pools revealed that QS leads to changes associated with decreased membrane fluidity and higher chemical stability. However, not all of the changes we observed were necessarily a direct consequence of QS; liquid chromatography (LC)-MS analyses revealed that polyamine levels were elevated in thelasI rhlImutant, perhaps a response to the absence of QS-dependent adaptations. Our data suggest that QS leads to a global readjustment in central metabolism and provide new insight into the metabolic changes associated with QS during stationary-phase adaptation.IMPORTANCEQuorum sensing (QS) is a transcriptional regulatory mechanism that allows bacteria to coordinate their gene expression profile with the population cell density. The opportunistic human pathogenPseudomonas aeruginosauses QS to control the production of secreted virulence factors. In this study, we show that QS elicits a global “metabolic rewiring” inP. aeruginosa. This metabolic rerouting of fluxes is consistent with a variety of drivers, ranging from altered QS-dependent transcription of “metabolic genes” through to the effect(s) of global “metabolic readjustment” as a consequence of QS-dependent exoproduct synthesis, as well as a general stress response, among others. To our knowledge, this is the first study of its kind to assess the global impact of QS on the metabolome.

FATTY ACID METHYL ESTER (FAME) ANALYSIS FOR MONITORING NOCARDIA LEVELS IN ACTIVATED SLUDGE

2001 ◽  
Vol 2001 (15) ◽  
pp. 780-788
Author(s):  
Il-Kyu Kim ◽  
Daniel K. Cha ◽  
Jeffry J. Fuhrmann ◽  
Ik-Tae Yeom ◽  
Kyu-Hong Ahn
Keyword(s):  
Fatty Acid ◽  
Methyl Ester ◽  
Activated Sludge ◽  
Fatty Acid Methyl Ester ◽  
Acid Methyl Ester ◽  
Fame Analysis ◽  
Acid Methyl
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