Monitoring Bioadhesion and Biofim Formation Within Biopits in Archaeological Potsherds by Microscopic Techniques

SOTO, DAIANA; GUTAROWSKA, BEATA; OTLEWSKA, ANNA; GUIAMET, PATRICIA; RAJKOWSKA, KATARZYNA

MICROSCOPY & MICROANALYSIS

CAMBRIDGE UNIV PRESS

Año: 2020 vol. 26 p. 109 - 110

1431-9276

Even when Pseudomonas aeruginosa pathogenicity has been well recognized by clinic medicine and vetliterature, few it is known regarding to strains isolated from archaeological materials. Recent studieshave demonstrated that strains of P. aeruginosa with a high adaptive ability to colonize and developbiofilm in inorganic surfaces of archaeological ceramics exist [1].The potsherds samples from which P. aeruginosa was isolated are of Rustic pottery (Fig. 1), usually fordomestic, and they came from the archaeological site La Cuestecilla, Northern of La Rioja province,Argentina. To assess the bioadhesión and biofilm formation ability of this strain adapted to inorganicmaterials, experimental assays were performed with samples of the same ceramic type from which theywere identify. Firstly, the strain was seeded on solid mineral medium [2] and then in contact witharchaeological ceramics samples. The bioadhesion and biofilm formation was assessed after anincubation time by scanning electron miscroscopy (SEM-EDAX Fem Quanta 200 TM ? LIMF, UNLP).The samples were kept in a closed chamber with ethanol (100%) for 24 h. Previously to observation byscanning electron microscopy, a part of the samples were cleaned by utrasonic to evaluatebiodeterioration processes in its surface, while the other were metalized with Au to increase imageresolution to observe bioadhesion and biofilm formation. Potsherds without treatment were used ascontrol samples and were analysed by stereomicroscopy (Olympus BH2, INIFTA-CONICET) and SEM.Cyanolichens colonized weakened ceramics surfaces by weathering and erosion processes (Fig. 1). Theresults proved that cyanolichens left biopits of subcircular shapes of approximated 0,5-1,5 mm (Fig. 2a)that later are used, along with surface irregularities, by P. aeruginosa to develop (Fig. 2b). Even thougharchaeological potsherds did not have clearly defined biofilms such as those obtained byexperimentation, the production of exopolimeric substances (EPS) and biofilm formation by P.aeruginosa it is corroborate, such as its pathogenicity and risk in the handling of such cultural objects