6533b82cfe1ef96bd128ffbc
RESEARCH PRODUCT
Polysaccharide-based silver nanoparticles synthesized by Klebsiella oxytoca DSM 29614 cause DNA fragmentation in E-coli cells
Giuseppe GalloAnna Maria PugliaDario BattistelMichele GalloSalvatore DanieleFranco BaldiOreste PiccoloClaudia FaleriStefano Paganellisubject
0301 basic medicineSilverLysisCell lysisAntimicrobial activity Cell lysis Silver exopolysaccharide nanoparticles Silver in DNA Silver releaseMetal NanoparticlesDNA FragmentationMicrobial Sensitivity Tests02 engineering and technologyAntimicrobial activityCell morphologymedicine.disease_causeSettore BIO/19 - Microbiologia GeneraleCell lysiKocuria rhizophilaGeneral Biochemistry Genetics and Molecular BiologySilver nanoparticleMicrobiologyBiomaterials03 medical and health sciencesBioreactorsEscherichia colimedicineEscherichia coliBiochemistry Genetics and Molecular Biology (all)biologySilver exopolysaccharide nanoparticlesSilver in DNAPolysaccharides BacterialKlebsiella oxytocaMetals and AlloysKlebsiella oxytoca021001 nanoscience & nanotechnologybiology.organism_classificationSilver exopolysaccharide nanoparticleBiomaterialAnti-Bacterial Agents030104 developmental biologyAgricultural and Biological Sciences (all)Silver releaseDNA fragmentation25060210 nano-technologyGeneral Agricultural and Biological SciencesMicrococcus luteusNuclear chemistrydescription
Silver nanoparticles (AgNPs), embedded into a specific exopolysaccharide (EPS), were produced by Klebsiella oxytoca DSM 29614 by adding AgNO3 to the cultures during exponential growth phase. In particular, under aerobic or anaerobic conditions, two types of silver nanoparticles, named AgNPs-EPS(aer) and the AgNPs-EPS(anaer), were produced respectively. The effects on bacterial cells was demonstrated by using Escherichia coli K12 and Kocuria rhizophila ATCC 9341 (ex Micrococcus luteus) as Gram-negative and Gram-positive tester strains, respectively. The best antimicrobial activity was observed for AgNPs-EPS(aer), in terms of minimum inhibitory concentrations and minimum bactericidal concentrations. Observations by transmission electron microscopy showed that the cell morphology of both tester strains changed during the exposition to AgNPs-EPS(aer). In particular, an electron-dense wrapped filament was observed in E. coli cytoplasm after 3 h of AgNPs-EPS(aer) exposition, apparently due to silver accumulation in DNA, and both E. coli and K. rhizophila cells were lysed after 18 h of exposure to AgNPs-EPS(aer). The DNA breakage in E. coli cells was confirmed by the comparison of 3-D fluorescence spectra fingerprints of DNA. Finally the accumulation of silver on DNA of E. coli was confirmed directly by a significant Ag(+) release from DNA, using the scanning electrochemical microscopy and the voltammetric determinations.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-01-01 |