Browsing by Author "Giussani, Barbara"

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Efficacy of zosteric acid sodium salt on the yeast biofilm model Candida albicans
(2011-05) Villa, Federica; Stewart, Philip S.; Giussani, Barbara; Roncoroni, S.; Albanese, Domenico; Giordano, C.; Tunesi, M.; Cappitelli, Francesca
Candida albicans is the most notorious and the most widely studied yeast biofilm former. Design of experiments (DoE) showed that 10 mg/L zosteric acid sodium salt reduced C. albicans adhesion and the subsequent biofilm formation by at least 70%, on both hydrophilic and hydrophobic surfaces of 96-well plates. Indeed, biofilm imaging revealed the dramatic impact of zosteric acid sodium salt on biofilm thickness and morphology, due to the inability of the cells to form filamentous structures while remaining metabolically active. In the same way, 10 mg/L zosteric acid sodium salt inhibited C. albicans biofilm formation when added after the adhesion phase. Contrary to zosteric acid sodium salt, methyl zosterate did not affect yeast biofilm. In addition, zosteric acid sodium salt enhanced sensitivity to chlorhexidine, chlorine, hydrogen peroxide, and cis-2-decenoic acid, with a reduction of 0.5 to 8 log units. Preliminary in vitro studies using suitable primary cell based models revealed that zosteric acid sodium salt did not compromise the cellular activity, adhesion, proliferation or morphology of either the murine fibroblast line L929 or the human osteosarcoma line MG-63. Thus the use of zosteric acid sodium salt could provide a suitable, innovative, preventive, and integrative approach to preventing yeast biofilm formation.
Hindering biofilm formation with zosteric acid
(2010-07) Villa, Federica; Albanese, Domenico; Giussani, Barbara; Stewart, Philip S.; Daffonchio, Daniele; Cappitelli, Francesca
The antifoulant, zosteric acid, was synthesized using a non-patented process. Zosteric acid at 500 mg l-1 caused a reduction of bacterial (Escherichia coli, Bacillus cereus) and fungal (Aspergillus niger, Penicillium citrinum) coverage by 90% and 57%, respectively. Calculated models allowed its antifouling activity to be predicted at different concentrations. Zosteric acid counteracted the effects of some colonization-promoting factors. Bacterial and fungal wettability was not affected, but the agent increased bacterial motility by 40%. A capillary accumulation test showed that zosteric acid did not act as a chemoeffector for E. coli, but stimulated a chemotactic response. Along with enhanced swimming migration of E. coli in the presence of zosteric acid, staining showed an increased production of flagella. Reverse transcriptase-PCR revealed an increased transcriptional level of the fliC gene and isolation and quantification of flagellar proteins demonstrated a higher flagellin amount. Biofilm experiments confirmed that zosteric acid caused a significant decrease in biomass (-92%) and thickness (-54%).