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The aims of this work were to: (i) microscopically analyse the pre- and post-Columbian archaeological textiles using Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM-EDX); (ii) microbiologically analyse the archaeological textiles (from the Southern Andean Area, La Plata Museum); (iii) determine the ability of Pseudomonas sp. isolates from archaeological textiles to biofilm formation by SEM; (iv) assess the anti-biofilm properties of AgNPs protecting cotton against Pseudomonas sp. Results showed the presence of bacteria with proteolytic and lipolytic activities on archaeological textiles, including Clostridium sp. and Pseudomonas aeruginosa. Two nucleotide sequences of 16S ribosomal RNA gene of P. aeruginosa strains were deposited in GeneBank NCBI database with accession numbers: KP842564 (strain 1) and KP842565 (strain 2). Those strains exhibited different morphological and growth characteristics: strain 1 with ability to form biofilms on archaeological textiles was rod-shaped, produced bluish-green pigment, and smaller than strain 2; and strain 2 was pleomorphic and produced brown pigment. The use of silver nanoparticles (90 ppm, φ 10–80 nm) allowed to protecting textiles against P. aeruginosa growth by 63%–97%, depending on the strain and exposition time., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

The objectives of the paper were to evaluate the microbial prevalence inside the buildings of the Photographic Library of the National Archive of the Republic of Cuba (PLNARC) and of the Historical Archive of the Museum of La Plata (HAMP) and to estimate the levels of microbial contamination on photos stored in these repositories. We have also examined some of the physiological features of fungal and bacterial isolates in order to evaluate their potential for biodeterioration. A sedimentation method was used for the microbiological sampling of air, while sterile cotton swabs were used for sampling documents. Petri dishes with appropriate selective culture media were used to isolate fungi and bacteria. The cellulolytic, proteolytic, and amylolytic activities and the production of acids and pigments of the fungal isolates were qualitatively determined. The predominant fungal genera in the air of both institutions were Cladosporium and Penicillium, respectively, for PLNARC and HAMP. At both places, the prevalent bacterial isolates were Gram positive. Among the microbial isolates from photos, various fungal and bacterial isolates were capable of degrading starch and protein and also to excrete acids and pigments, which constitute a high potential risk for the biodeterioration of these documents.

The efficacy of ozone biocidal action against planktonic and sessile Pseudomonas fluorescens was studied using different contact times and biocide concentrations. Bacterial biofilms were formed on different metallic substrata frequently used as structural materials in industrial installations. The results showed that the biocidal action of ozone against planktonic cells can be represented by a dose‐response relationship in which the contact time factor was more significant than the concentration. The efficacy of ozone against sessile bacteria was lower than that found for planktonic cells. Turbulent flow significantly improved the inactivation rate, suggesting that a diffusional impediment was involved in the mass transfer process. However, diffusional resistance alone cannot explain the observed decrease in biocidal efficacy. Ozone penetration into the biofilm appeared to be a function of simultaneous diffusion and a reaction of the biocide in the biofilm matrix; the latter may be the result of microscal...

An immunonoglobulin solution containing IgA, IgG and IgM was used to prevent theformation of Pseudomonas fluorescens ( P. fluorescens ) biofilms on carbonsteel and two different types of stainless steel (SS) of industrial grade. A marked inhibition ofbacterial adhesion was found when an immunoglobulin film was formed on the metal surface priorto the immersion of the sample in bacterial cultures. Microscopic techniques like scanning electronmicroscopy (SEM) and environmental scanning electron microscopy (ESEM) were used forassessing adhesion inhibition. The electrochemical behavior of the steels was evaluated by meansof potentiodynamic runs, corrosion potential vs. time evolution and linear polarization resistancetechniques applied in the presence and the absence of the immunoglobulins.

Pre and post-Columbian archeological textiles from the Southern Andean area, sheltered in Deposit 25 at La Plata Museum (Fig. 1), were analyzed by Olympus BX51optical microscopy (OM), FEI Quanta 200 scanning electron microscopy (SEM) and Leica SP5 confocal laser scanning microscopy (CLSM) with the aim of studying their biodeterioration3 . For over 120 years, these textiles have provided information to archeologists around the world, and it was through the study of many pieces that we now know in detail the characteristics of the material culture of the various groups that inhabited the territory during the national Holocene period., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Exactas, Facultad de Ciencias Veterinarias

Stone materials exposed to weathering are subject to biological colonization and consequently to biofilm formation, causing biodeterioration. The color changes on the stone substrates caused by biogenic pigments, mechanical stress on the mineral structure due to extracellular polymeric substances (EPS) and the accumulation of atmospheric pollutants by the biofilm are some of the deteriogenic effects, which modify esthetic and functional aspects of the work. The aim of this study was to determine biodeterioration and biofilm formation on marble tombstones from La Recoleta Cemetery, Buenos Aires, Argentina. The effect of the biocide benzalkonium chloride on biofilm formation was studied, and a chart produced of the treated tombstones. Pre- and post-intervention microbiological studies, scanning electron microscopy and X-ray dispersion analysis showed a significant decrease of the biofilm flora after treatment. However, algae of the genus Trentepohlia were difficult to eradicate. These studies are a valuable contribution to determine restoration criteria against biofilm formation, to characterize chromatic variations of biological origin on the stone and to formulate conservation and restoration policies. Fil: Guiamet, Patricia Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentina Fil: Crespo, Miguel. Ciudad de Buenos Aires. Ministerio de Cultura. Subsecretaría de Patrimonio; Argentina Fil: Lavin, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Ponce, Beatriz. Secretaría de Industria y Minería. Servicio Geologico Minero Argentino; Argentina Fil: Gaylarde, Christine. University of Portsmouth; Reino Unido Fil: Gómez de Saravia, Sandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentina

The aims of this paper were to study the biofouling and biodeterioration of photos and maps stored at Historical Archive of the Museum of La Plata (HAMP), Argentine, and two repositories of the National Archive of Cuba Republic (NARC) and to carry out the physiological characterization of the isolated fungi and bacteria. The role of the environmental microbiota in the biofouling formation was also studied. Microbial assemblages in the air were sampled by sedimentation technique while those on documents were sampled by swabbering. Biofilm formation and biofouling were monitored by scanning electron microscope (SEM). Large microbial assemblages were found at NARC archives with the prevalence of genera Aspergillus, Cladosporium and Penicillium, whereas at HAMP these values were lower, Penicillium was the only fungal genus detected. Most of the fungi degraded cellulose and produced pigments and acids, and all of the isolated bacteria had proteolytic and/or cellulolytic activity. In all cases, a higher concentration of viable bacteria than of fungi was isolated from documents. These results correlated with bacterial values detected in air at NARC repositories. However, this correlation cannot be observed at HAMP where Aspergillus, Penicillium and Talaromyces helicus (teleomorph of Penicillium) were isolated. It is the first time that the last genus is reported in documents.

SAE 1020 carbon steel samples were tested in laboratory experiments using two different microbial strains isolated from cutting-oil emulsions: Pseudomonas fluorescens and Desulfovibrio vul...

Biofilms containing single or mixed cultures of the fungus Hormoconis resinae and anaerobic sulphate-reducing bacteria (SRB) on stainless steel were incubated with an isothiazolone biocide (Kathon FP) at 28°C for 24 h. H. resinae within the biofilm was enumerated by immunofluorescence microscopy using specific antiserum, and SRB were assayed by culture. Fungal numbers in mixed biofilms were considerably reduced in comparison with those in pure biofilms. The biocide was shown to be effective against H. resinae in pure biofilms at 50 and 100 ppm, but in mixed biofilms only at the higher concentration. This concentration also reduced the sessile SRB numbers by 99%.