Search results for "pseudomonas"
showing 10 items of 364 documents
Daļēji ar stronciju aizvietotu hidroksil-peroksiapatītu analītiska raksturošana un antibakteriālo īpašību izpēte
2018
Daļēji ar stronciju aizvietotu hidroksil-peroksiapatītu analītiska raksturošana un antibakteriālo īpašību izpēte. Valkovska V., darba vadītāja docente, Dr. chem. Osīte A. Maģistra darbs, 72 lappuses, 26 attēli, 15 tabulas, 126 literatūras avoti, 8 pielikumi. Latviešu valodā. Darbā ir apkopota informācija par hidroksilapatītu un hidroksil-peroksiapatītu iegūšanu, fizikālajām un ķīmiskajām īpašībām, izmantošanu, analīzes metodēm, kalcija fosfātu biomateriālu mikrobioloģiskajām īpašībām, to antibakteriālās aktivitātes un toksicitātes novērtēšanu, stabilo izotopu sastāvu bioloģiskajā apatītā. Eksperimentālajā daļā veiktas kalcija hidroksilapatīta un daļēji ar stronciju aizvietotu hidroksilapatī…
Novel Paraoxonase 2-Dependent Mechanism Mediating the Biological Effects of the Pseudomonas aeruginosa Quorum-Sensing Molecule N-(3-Oxo-Dodecanoyl)-l…
2015
ABSTRACT Pseudomonas aeruginosa produces N -(3-oxo-dodecanoyl)- l -homoserine lactone (3OC12), a crucial signaling molecule that elicits diverse biological responses in host cells thought to subvert immune defenses. The mechanism mediating many of these responses remains unknown. The intracellular lactonase paraoxonase 2 (PON2) hydrolyzes and inactivates 3OC12 and is therefore considered a component of host cells that attenuates 3OC12-mediated responses. Here, we demonstrate in cell lines and in primary human bronchial epithelial cells that 3OC12 is rapidly hydrolyzed intracellularly by PON2 to 3OC12 acid, which becomes trapped and accumulates within the cells. Subcellularly, 3OC12 acid acc…
1,2,4-Oxadiazole topsentin analogs as staphylococcal biofilm inhibitors targeting the bacterial transpeptidase sortase A
2020
The inhibition or prevention of biofilm formation represents an emerging strategy in the war against antibiotic resistance, interfering with key players in bacterial virulence. This approach includes the inhibition of the catalytic activity of transpeptidase sortase A (Srt A), a membrane enzyme responsible for covalently attaching a wide variety of adhesive matrix molecules to the peptidoglycan cell wall in Gram-positive strains. A new series of seventeen 1,2,4-oxadiazole derivatives was efficiently synthesized and screened as potential new anti-virulence agents. The ability of inhibiting biofilm formation was evaluated against both Gram-positive and Gram-negative pathogens. Remarkably, all…
2,6-Disubstituted imidazo[2,1-b][1,3,4]thiadiazole derivatives as potent staphylococcal biofilm inhibitors.
2019
Abstract A class of 36 new 2-(6-phenylimidazo[2,-1-b][1,3,4]thiadiazol-2-yl)-1H-indoles was efficiently synthesized and evaluated for their anti-biofilm properties against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923, S. aureus ATCC 6538 and Staphylococcus epidermidis ATCC 12228, and the Gram-negative strains Pseudomonas aeruginosa ATCC 15442 and Escherichia coli ATCC 25922. Many of these new compounds, were able to inhibit biofilm formation of the tested staphylococcal strains showing BIC50 lower than 10 μg/ml. In particular, derivatives 9c and 9h showed remarkable anti-biofilm activity against S. aureus ATCC 25923 with BIC50 values of 0.5 and 0.8 μg/ml, r…
Echinoderm Antimicrobial Peptides to Contrast Human Pathogens
2013
Increased attention has been focused in marine invertebrates as a source of bioactive molecules for biomedical applications. Many bioactive molecules are part of the innate immune system. Some more recently isolated compounds, mainly from sea urchin and sea cucumber are antimicrobial peptides (AMP) active against Gram positive, Gram negative and fungi. In this review we described the most recent studies on AMP isolated from echinoderms. The AMP are little peptides <10 kDa with cationic charge and amphipathic structure. Recently, it was demonstrated that in the coelomocyte lysates of Paracentrotus. lividus and Holothuria tubulosa AMP are present with activity against staphylococcal and Pseud…
Antimicrobial peptides from echinoderms as antibiofilm agents: a natural strategy to combat bacterial infections
2014
AbstractIncreased attention has been focused on marine invertebrates as a source of bioactive molecules for biomedical applications. Many bioactive molecules are part of the innate immune system. Some more recently isolated compounds, mainly from the sea urchin and the sea cucumber, are antimicrobial peptides (AMPs) active against Gram-positive and Gram-negative bacteria, and fungi. In this review we described the most recent studies on AMPs isolated from echinoderms. AMPs are small peptides (< 10 kDa) with cationic charge and amphipathic structure. Recently, it was demonstrated that in the coelomocyte lysates of Paracentrotus lividus and Holothuria tubulosa, AMPs possess activity against s…
Immune mediators of sea-cucumber Holothuria tubulosa (Echinodermata) as source of novel antimicrobial and anti-staphylococcal biofilm agents
2013
The present study aims to investigate coelomocytes, immune mediators cells in the echinoderm Holothuria tubulosa, as an unusual source of antimicrobial and antibiofilm agents. The activity of the 5kDa peptide fraction of the cytosol from H. tubulosa coelomocytes (5-HCC) was tested against a reference group of Gram-negative and Gram-positive human pathogens. Minimal inhibitory concentrations (MICs) ranging from 125 to 500 mg/ml were determined against tested strains. The observed biological activity of 5-HCC could be due to two novel peptides, identified by capillary RP-HPLC/nESI-MS/MS, which present the common chemical-physical characteristics of antimicrobial peptides. Such peptides were c…
Encapsulation of the Bacillus thuringiensis secretable toxins Vip3Aa and Cry1Ia in Pseudomonas fluorescens
2013
Vip3A and Cry1I toxins are secreted during the vegetative growth of Bacillus thuringiensis. Vip3A toxins do not share homology to the crystal (Cry) proteins and are active against a different spectrum of lepidopteran species. Cry1I toxins share similarity with the Cry1 protein group but do not accumulate in the parasporal crystal. Since Vip3A and Cry1I toxins are released from the cell, they are excluded from biological formulates based on spores and crystals of B. thuringiensis. As an approach to obtain novel sprayable insecticides containing Vip3 or Cry1I toxins, Vip3Aa and Cry1Ia proteins were expressed in Pseudomonas fluorescens. This bacterium, non-pathogenic to animals or plants, can …
Siderophore typing, a powerful tool for the identification of fluorescent and nonfluorescent Pseudomonas
2002
ABSTRACT A total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through siderotyping, i.e., by the isoelectrophoretic characterization of their main siderophores and pyoverdines and determination of the pyoverdine-mediated iron uptake specificity of the strains. As a general rule, strains within a well-circumscribed taxonomic group, namely the species Pseudomonas brassicacearum , Pseudomonas fuscovaginae , Pseudomonas jessenii , Pseudomonas mandelii , Pseudomonas monteilii , “ Pseudomonas mosselii ,” “ Pseudomonas palleronii ,” Pseudomonas rhodesiae , “ Pseudomonas salomonii ,” Pseudomonas syringa…