scholarly journals Further studies of the chemical composition of the lipopolysaccharide of Pseudomonas aeruginosa

1972 ◽  
Vol 126 (2) ◽  
pp. 395-407 ◽  
Author(s):  
I. R. Chester ◽  
G. W. Gray ◽  
S. G. Wilkinson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Large Scale ◽  
Lipid A ◽  
Thiobarbituric Acid ◽  
Molar Ratio ◽  
Positive Component ◽  
Qualitative And Quantitative ◽  
Alkaline Methanolysis ◽  
Molecular Weight Fractions ◽  
High Voltage Electrophoresis

1. Qualitative and quantitative analytical results for the lipopolysaccharide from acetone-dried cells of Pseudomonas aeruginosa (N.C.T.C. 1999) are presented and possible contamination of the material with nucleic acid was further examined. 2. Additional sugars detected (only in large-scale hydrolysates) were mannose and arabinose; traces of spermidine and putrescine were also found. 3. The heptose component is l-glycero-d-mannoheptose. 4. The thiobarbituric acid-positive component is a 3-deoxy-2-octulonic acid, of which only 35–40% links lipid A to the polysaccharide. This linkage is not broken by hydrolysis with acetic acid up to 0.08m. 5. Liberation of lipid A required hydrolysis with 0.1m-hydrochloric acid, which substantially degraded the polysaccharide moiety. 6. Fractions obtained from the degraded polysaccharide by high-voltage electrophoresis were examined; in these, the alanine/galactosamine molar ratio is approx. 1. 7. Hydrazinolysis of whole lipopolysaccharide showed that at least 40% of the alanine is in amide linkage, possibly with galactosamine. 8. Lipid A, solubilized by alkaline methanolysis was fractionated; most of the phosphorus of the higher-molecular-weight fractions was released as Pi by a phosphomonoesterase. 9. Hydrazinolysis of lipid A destroyed approx. 80% of the glucosamine, and glycosidically linked glucosamine oligosaccharides could not be isolated.

scholarly journals Studies of lipid A fractions from the lipopolysaccharides of Pseudomonas aeruginosa and Pseudomonas alcaligenes

1973 ◽  
Vol 133 (3) ◽  
pp. 563-572 ◽  
Author(s):  
David T. Drewry ◽  
James A. Lomax ◽  
George W. Gray ◽  
Stephen G. Wilkinson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Gel Filtration ◽  
Structural Features ◽  
Partial Hydrolysis ◽  
Hexadecanoic Acid ◽  
Alkaline Methanolysis ◽  
Pseudomonas Alcaligenes ◽  
Hydrolysis Of ◽  
Derivatives Of

Lipid A fractions from Pseudomonas aeruginosa and Pseudomonas alcaligenes have similar compositions and structural features. By means of hydrazinolysis of the parent lipopolysaccharides and partial hydrolysis of the deacylation products, it was established that both lipids are derived from the β-(1→6)-linked disaccharide of glucosamine. Phosphorylated derivatives of the disaccharide from Ps. aeruginosa were also characterized. The lipids differ mainly in the absence of hexadecanoic acid and 2-hydroxydodecanoic acid from the lipid from Ps. alcaligenes. Evidence that in Ps. aeruginosa these acids are ester-linked to residues of 3-hydroxyalkanoic acids (including 3-hydroxydecanoic acid) was obtained. Heterogeneity of lipid A fractions was indicated by t.l.c., and by gel filtration of de-O-acylation products from mild alkaline methanolysis of the lipids.

scholarly journals Resistance and Heteroresistance to Colistin in Pseudomonas aeruginosa Isolates from Wenzhou, China

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Jie Lin ◽  
Chunquan Xu ◽  
Renchi Fang ◽  
Jianming Cao ◽  
Xiucai Zhang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Population Analysis ◽  
Colistin Resistance ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Expression Levels ◽  
Maldi Tof ◽  
Broth Microdilution Method ◽  
Tof Ms

ABSTRACT The goal was to investigate the mechanisms of colistin resistance and heteroresistance in Pseudomonas aeruginosa clinical isolates. Colistin resistance was determined by the broth microdilution method. Colistin heteroresistance was evaluated by population analysis profiling. Time-kill assays were also conducted. PCR sequencing was performed to detect the resistance genes among (hetero)resistant isolates, and quantitative real-time PCR assays were performed to determine their expression levels. Pulsed-field gel electrophoresis and multilocus sequence typing were performed. Lipid A characteristics were determined via matrix-assisted laser desorption–ionization time of flight mass spectrometry (MALDI-TOF MS). Two resistant isolates and 9 heteroresistant isolates were selected in this study. Substitutions in PmrB were detected in 2 resistant isolates. Among heteroresistant isolates, 8 of 9 heteroresistant isolates had nonsynonymous PmrB substitutions, and 2 isolates, including 1 with a PmrB substitution, had PhoQ alterations. Correspondingly, the expression levels of pmrA or phoP were upregulated in PmrB- or PhoQ-substituted isolates. One isolate also found alterations in ParRS and CprRS. The transcript levels of the pmrH gene were observed to increase across all investigated isolates. MALDI-TOF MS showed additional 4-amino-4-deoxy-l-arabinose (l-Ara4N) moieties in lipid A profiles in (hetero)resistant isolates. In conclusion, both colistin resistance and heteroresistance in P. aeruginosa in this study mainly involved alterations of the PmrAB regulatory system. There were strong associations between mutations in specific genetic loci for lipid A synthesis and regulation of modifications to lipid A. The transition of colistin heteroresistance to resistance should be addressed in future clinical surveillance.

scholarly journals Repeated isolation of an antibiotic-dependent and temperature-sensitive mutant of Pseudomonas aeruginosa from a cystic fibrosis patient

2020 ◽  
Author(s):  
Daniel J Wolter ◽  
Alison Scott ◽  
Catherine R Armbruster ◽  
Dale Whittington ◽  
John S Edgar ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Lipid A ◽  
Clinical Laboratory ◽  
Membrane Phospholipid ◽  
Growth Defect ◽  
Genetic Mutations ◽  
Temperature Sensitive ◽  
Isolation And Characterization

Abstract Background Bacteria adapt to survive and grow in different environments. Genetic mutations that promote bacterial survival under harsh conditions can also restrict growth. The causes and consequences of these adaptations have important implications for diagnosis, pathogenesis, and therapy. Objectives We describe the isolation and characterization of an antibiotic-dependent, temperature-sensitive Pseudomonas aeruginosa mutant chronically infecting the respiratory tract of a cystic fibrosis (CF) patient, underscoring the clinical challenges bacterial adaptations can present. Methods Respiratory samples collected from a CF patient during routine care were cultured for standard pathogens. P. aeruginosa isolates recovered from samples were analysed for in vitro growth characteristics, antibiotic susceptibility, clonality, and membrane phospholipid and lipid A composition. Genetic mutations were identified by whole genome sequencing. Results P. aeruginosa isolates collected over 5 years from respiratory samples of a CF patient frequently harboured a mutation in phosphatidylserine decarboxylase (psd), encoding an enzyme responsible for phospholipid synthesis. This mutant could only grow at 37°C when in the presence of supplemented magnesium, glycerol, or, surprisingly, the antibiotic sulfamethoxazole, which the source patient had repeatedly received. Of concern, this mutant was not detectable on standard selective medium at 37°C. This growth defect correlated with alterations in membrane phospholipid and lipid A content. Conclusions A P. aeruginosa mutant chronically infecting a CF patient exhibited dependence on sulphonamides and would likely evade detection using standard clinical laboratory methods. The diagnostic and therapeutic challenges presented by this mutant highlight the complex interplay between bacterial adaptation, antibiotics, and laboratory practices, during chronic bacterial infections.

scholarly journals Lipid A precursor from Pseudomonas aeruginosa is completely acylated prior to addition of 3-deoxy-D-manno-octulosonate.

1988 ◽  
Vol 263 (11) ◽  
pp. 5217-5223
Author(s):  
R C Goldman ◽  
C C Doran ◽  
S K Kadam ◽  
J O Capobianco
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Lipid A

scholarly journals The extraction of cell walls of Pseudomonas aeruginosa with aqueous phenol. The insoluble residue and material from the aqueous layers

1967 ◽  
Vol 105 (2) ◽  
pp. 759-765 ◽  
Author(s):  
K. Clarke ◽  
G. W. Gray ◽  
D. A. Reaveley
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Cell Walls ◽  
Lipid A ◽  
Diaminopimelic Acid ◽  
Insoluble Residue ◽  
Muramic Acid ◽  
Gram Negative ◽  
Gram Negative Organisms ◽  
Residue Fraction

1. The insoluble residue and material present in the aqueous layers resulting from treatment of cell walls of Pseudomonas aeruginosa with aqueous phenol were examined. 2. The products (fractions AqI and AqII) isolated from the aqueous layers from the first and second extractions respectively account for approx. 25% and 12% of the cell wall and consist of both lipopolysaccharide and muropeptide. 3. The lipid part of the lipopolysaccharide is qualitatively similar to the corresponding material (lipid A) from other Gram-negative organisms, as is the polysaccharide part. 4. The insoluble residue (fraction R) contains sacculi, which also occur in fraction AqII. On hydrolysis, the sacculi yield glucosamine, muramic acid, alanine, glutamic acid and 2,6-diaminopimelic acid, together with small amounts of lysine, and they are therefore similar to the murein sacculi of other Gram-negative organisms. Fraction R also contains substantial amounts of protein, which differs from that obtained from the phenol layer. 5. The possible association or aggregation of lipopolysaccharide, murein and murein sacculi is discussed.

Integrated mass spectrometry-based multi-omics for elucidating mechanisms of bacterial virulence

2021 ◽  
Author(s):  
Lok Man ◽  
William P. Klare ◽  
Ashleigh L. Dale ◽  
Joel A. Cain ◽  
Stuart J. Cordwell
Keyword(s):  
Mass Spectrometry ◽  
Protein Interactions ◽  
Large Scale ◽  
Lipid A ◽  
Phenotypic Characterization ◽  
Post Translational Modification ◽  
Form Of Life ◽  
Antimicrobial Interventions

Despite being considered the simplest form of life, bacteria remain enigmatic, particularly in light of pathogenesis and evolving antimicrobial resistance. After three decades of genomics, we remain some way from understanding these organisms, and a substantial proportion of genes remain functionally unknown. Methodological advances, principally mass spectrometry (MS), are paving the way for parallel analysis of the proteome, metabolome and lipidome. Each provides a global, complementary assay, in addition to genomics, and the ability to better comprehend how pathogens respond to changes in their internal (e.g. mutation) and external environments consistent with infection-like conditions. Such responses include accessing necessary nutrients for survival in a hostile environment where co-colonizing bacteria and normal flora are acclimated to the prevailing conditions. Multi-omics can be harnessed across temporal and spatial (sub-cellular) dimensions to understand adaptation at the molecular level. Gene deletion libraries, in conjunction with large-scale approaches and evolving bioinformatics integration, will greatly facilitate next-generation vaccines and antimicrobial interventions by highlighting novel targets and pathogen-specific pathways. MS is also central in phenotypic characterization of surface biomolecules such as lipid A, as well as aiding in the determination of protein interactions and complexes. There is increasing evidence that bacteria are capable of widespread post-translational modification, including phosphorylation, glycosylation and acetylation; with each contributing to virulence. This review focuses on the bacterial genotype to phenotype transition and surveys the recent literature showing how the genome can be validated at the proteome, metabolome and lipidome levels to provide an integrated view of organism response to host conditions.

Assessing Triangulation Across Methodologies, Methods, and Stakeholder Groups: The Joys, Woes, and Politics of Interpreting Convergent and Divergent Data

2018 ◽  
Vol 41 (1) ◽  
pp. 125-144 ◽  
Author(s):  
Rebecca Campbell ◽  
Rachael Goodman-Williams ◽  
Hannah Feeney ◽  
Giannina Fehler-Cabral
Keyword(s):  
Large Scale ◽  
Contextual Information ◽  
Policy Makers ◽  
Specific Data ◽  
Qualitative And Quantitative ◽  
Stakeholder Groups ◽  
Data Points ◽  
Evaluation Project ◽  
Collection Methods

The purpose of this study was to develop triangulation coding methods for a large-scale action research and evaluation project and to examine how practitioners and policy makers interpreted both convergent and divergent data. We created a color-coded system that evaluated the extent of triangulation across methodologies (qualitative and quantitative), data collection methods (observations, interviews, and archival records), and stakeholder groups (five distinct disciplines/organizations). Triangulation was assessed for both specific data points (e.g., a piece of historical/contextual information or qualitative theme) and substantive findings that emanated from further analysis of those data points (e.g., a statistical model or a mechanistic qualitative assertion that links themes). We present five case study examples that explore the complexities of interpreting triangulation data and determining whether data are deemed credible and actionable if not convergent.

scholarly journals LABORATE TEST FOR FE LEVELS IN KELAKAI BISCUITS

2020 ◽  
Vol 6 (2) ◽  
pp. 76-80
Author(s):  
Febby Siharina ◽  
Fitri Yuliana ◽  
Agustinus Hermino S. Putra
Keyword(s):  
Iron Deficiency ◽  
Pregnant Women ◽  
Adolescent Girls ◽  
Large Scale ◽  
Food Sources ◽  
Research Results ◽  
Qualitative And Quantitative ◽  
Quantitative Test

As one of the causes of anemia, iron deficiency must be overcome immediately, one of which is by finding taste-friendly food sources that can be consumed easily by anyone who is prone to anemia. This research was conducted in laboratory to determine the levels of iron in Kelakai biscuits which are assumed to be a source of food to treat anemia in adolescent girls or pregnant women. Qualitative and quantitative test were used to obtain the desired results. Based on the research results, it was found that each Kelakai biscuit contained an Fe level of 245 mg/g, which means that the formulation of the Kelakai biscuit could meet the daily needs of iron when consumed 3-4 chips per day based on the absorption of Fe in adults. Therefore, to further prove the effectiveness of these biscuits in preventing anemia, studies involving samples, either small or large scale, are highly recommended.

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