Antibacterial effect of hyaluronan/chitosan nanofilm in the initial adhesion of Pseudomonas aeruginosa wild type, and IV pili and LPS mutant strains

2021 ◽  
pp. 101415
Author(s):  
Jacobo Hernandez-Montelongo ◽  
Gianlucca G. Nicastro ◽  
Thays de O. Pereira ◽  
Mariana Zavarize ◽  
Marisa M. Beppu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Effect ◽  
Wild Type ◽  
Initial Adhesion ◽  
Mutant Strains

scholarly journals Investigation of the physiological relationship between the cyanide-insensitive oxidase and cyanide production in Pseudomonas aeruginosa

Microbiology ◽  
2006 ◽  
Vol 152 (5) ◽  
pp. 1407-1415 ◽  
Author(s):  
James E. A. Zlosnik ◽  
Gholam Reza Tavankar ◽  
Jacob G. Bundy ◽  
Dimitris Mossialos ◽  
Ronan O'Toole ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Opportunistic Pathogen ◽  
Wild Type ◽  
Toxic Agent ◽  
Stationary Phase Culture ◽  
Prolonged Incubation ◽  
Mutant Strains ◽  
Electron Sink ◽  
Culture Supernatants

Pseudomonas aeruginosa is an opportunistic pathogen which demonstrates considerable respiratory versatility, possessing up to five terminal oxidases. One oxidase, the cyanide-insensitive oxidase (CIO), has been previously shown to be resistant to the potent respiratory inhibitor cyanide, a toxin that is synthesized by this bacterium. This study investigated the physiological relationship between hydrogen cyanide production and the CIO. It was found that cyanide is produced in P. aeruginosa at similar levels irrespective of its complement of CIO, indicating that the CIO is not an obligatory electron sink for cyanide synthesis. However, MICs for cyanide and growth in its presence demonstrated that the CIO provides P. aeruginosa with protection against the effects of exogenous cyanide. Nevertheless, the presence of cyanide did not affect the viability of cio mutant strains compared to the wild-type during prolonged incubation in stationary phase. The detection of the fermentation end products acetate and succinate in stationary-phase culture supernatants suggests that P. aeruginosa, irrespective of its CIO complement, may in part rely upon fermentation for energy generation in stationary phase. Furthermore, the decrease in cyanide levels during incubation in sealed flasks suggested that active breakdown of HCN by the culture was taking place. To investigate the possibility that the CIO may play a role in pathogenicity, wild-type and cio mutant strains were tested in the paralytic killing model of Caenorhabditis elegans, a model in which cyanide is the principal toxic agent leading to nematode death. The CIO mutant had delayed killing kinetics, demonstrating that the CIO is required for full pathogenicity of P. aeruginosa in this animal model.

scholarly journals fleN, a Gene That Regulates Flagellar Number in Pseudomonas aeruginosa

2000 ◽  
Vol 182 (2) ◽  
pp. 357-364 ◽  
Author(s):  
Nandini Dasgupta ◽  
Shiwani K. Arora ◽  
Reuben Ramphal
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Motif ◽  
Gene Promoters ◽  
Wild Type ◽  
Electron Microscopic ◽  
Genome Database ◽  
Reading Frame ◽  
Mutant Strains ◽  
In The Wild ◽  
Flagellar Genes

ABSTRACT The single polar flagellum of Pseudomonas aeruginosaplays an important role in the pathogenesis of infection by this organism. However, regulation of the assembly of this organelle has not been delineated. In analyzing the sequence available at thePseudomonas genome database, an open reading frame (ORF), flanked by flagellar genes flhF and fliA, that coded for a protein (280 amino acids) with an ATP-binding motif at its N terminus was found. The ORF was inactivated by inserting a gentamicin cassette in P. aeruginosa PAK and PAO1. The resulting mutants were nonmotile on motility agar plates, but under a light microscope they exhibited random movement and tumbling behavior. Electron microscopic studies of the wild-type and mutant strains revealed that the mutants were multiflagellate, with three to six polar flagella per bacterium as rather than one as in the wild type, indicating that this ORF was involved in regulating the number of flagella and chemotactic motility in P. aeruginosa. The ORF was named fleN. An intact copy of fleN on a plasmid complemented the mutant by restoring motility and monoflagellate status. The β-galactosidase activities of eight flagellar operon or gene promoters in the wild-type andfleN mutant strains revealed a direct correlation between six promoters that were upregulated in the fleN mutant (fliLMNOPQ, flgBCDE, fliEFG,fliDS orf126, fleSR, and fliC) and positive regulation by FleQ, an NtrC-like transcriptional regulator for flagellar genes. Based on these results, we propose a model where FleN influences FleQ activity (directly or indirectly) in regulating flagellar number in P. aeruginosa.

scholarly journals Pseudomonas aeruginosa Cell-to-Cell Signaling Is Required for Virulence in a Model of Acute Pulmonary Infection

2000 ◽  
Vol 68 (7) ◽  
pp. 4331-4334 ◽  
Author(s):  
James P. Pearson ◽  
Matthew Feldman ◽  
Barbara H. Iglewski ◽  
Alice Prince
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Cell Signaling ◽  
Type Strain ◽  
Pulmonary Infection ◽  
Virulence Genes ◽  
Wild Type Strain ◽  
Wild Type ◽  
Neonatal Mice ◽  
Mutant Strains

ABSTRACT Cell-to-cell signaling controls many virulence genes inPseudomonas aeruginosa. We tested the virulence oflas and rhl quorum-sensing mutants in neonatal mice. A lasI rhlI double mutant was nearly avirulent, and the respective single mutant strains were reduced in virulence compared with the wild-type strain. Quorum sensing plays a role in P. aeruginosa pneumonia in neonatal mice.

scholarly journals Importance of the Exopolysaccharide Matrix in Antimicrobial Tolerance of Pseudomonas aeruginosa Aggregates

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Lise Goltermann ◽  
Tim Tolker-Nielsen
Keyword(s):  
Extracellular Matrix ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Treatment ◽  
Antibiotic Tolerance ◽  
Wild Type ◽  
Content Type ◽  
Extracellular Matrix Components ◽  
Mutant Strains ◽  
Matrix Components ◽  
Biofilm Matrix

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that can infect the lungs of cystic fibrosis (CF) patients and persist in the form of antibiotic-tolerant aggregates in the mucus. It has recently been suggested that such aggregates are formed due to restricted bacterial motility independent of the production of extracellular matrix components, and that they do not rely on an extracellular matrix for antimicrobial tolerance. However, we show here that biofilm matrix overexpression, as displayed by various clinical isolates, significantly protects P. aeruginosa aggregates against antimicrobial treatment. Alginate-overproducing mucA mutant bacteria growing in aggregates showed highly increased antibiotic tolerance compared to wild-type bacteria in aggregates. Deletion of algD in the mucA mutant strain abrogated alginate production and reversed the antibiotic tolerance displayed by the aggregates to a level similar to that observed for aggregates formed by the wild type. The P. aeruginosa ΔwspF and ΔyfiR mutant strains both overproduce Pel and Psl exopolysaccharide, and when these bacteria grew in aggregates, they showed highly increased antibiotic tolerance compared to wild-type bacteria growing in aggregates. However, the ΔwspF and ΔyfiR mutant strains, deficient in Pel/Psl production due to additional ΔpelA ΔpslBCD deletions, formed aggregates that displayed antibiotic tolerance levels close to those of wild-type aggregates. These results suggest that biofilm matrix components, such as alginate, Pel, and Psl, do play a role in the tolerance toward antimicrobials when bacteria grow as aggregates.

scholarly journals The hobo Transposable Element Excises and Has Related Elements in Tephritid Species

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1339-1347
Author(s):  
Alfred M Handler ◽  
Sheilachu P Gomez
Keyword(s):  
Drosophila Melanogaster ◽  
Ceratitis Capitata ◽  
Bactrocera Dorsalis ◽  
Parsimony Analysis ◽  
Wild Type ◽  
Anastrepha Suspensa ◽  
Tephritid Species ◽  
Mutant Strains ◽  
Almost All ◽  
Horizontal Transfers

Abstract Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays. Wild-type and mutant strains of Anastrepha suspensa, Bactrocera dorsalis, B. cucurbitae, Ceratitis capitata, and Toxotrypana curvicauda all supported hobo excision or deletion both in the presence and absence of co-injected hobo transposase, indicating a permissive state for hobo mobility and the existence of endogenous systems capable of mobilizing hobo. In several strains hobo helper reduced excision. Excision depended on hobo sequences in the indicator plasmid, though almost all excisions were imprecise and the mobilizing systems appear mechanistically different from hobo. hobe-related sequences were identified in all species except T. curvicauda. Parsimony analysis yielded a subgroup including the B. cucurbitae and C. capitata sequences along with hobo and Hermes, and a separate, more divergent subgroup including the A. suspensa and B. dorsalis sequences. All of the sequences exist as multiple genomic elements, and a deleted form of the B. cucurbitae element exists in B. dorsalis. The hobo-related sequences are probably members of the hAT transposon family with some evolving from distant ancestor elements, while others may have originated from more recent horizontal transfers.

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