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Even when Pseudomonas aeruginosa pathogenicity has been well recognized by clinic medicine and vet literature, few it is known regarding to strains isolated from archaeological materials. Recent studies have demonstrated that strains of P. aeruginosa with a high adaptive ability to colonize and develop biofilm in inorganic surfaces of archaeological ceramics exist. The potsherds samples from which P. aeruginosa was isolated are of Rustic pottery, usually for domestic, 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 inorganic materials, experimental assays were performed with samples of the same ceramic type from which they were identify. Firstly, the strain was seeded on solid mineral medium and then in contact with archaeological ceramics samples. The bioadhesion and biofilm formation was assessed after an incubation 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 by scanning electron microscopy, a part of the samples were cleaned by utrasonic to evaluate biodeterioration processes in its surface, while the other were metalized with Au to increase image resolution to observe bioadhesion and biofilm formation. Potsherds without treatment were used as control samples and were analysed by stereomicroscopy (Olympus BH2, INIFTA-CONICET) and SEM. Cyanolichens colonized weakened ceramics surfaces by weathering and erosion processes. The results proved that cyanolichens left biopits of subcircular shapes of approximated 0,5-1,5 mm that later are used, along with surface irregularities, by P. aeruginosa to develop. Even though archaeological potsherds did not have clearly defined biofilms such as those obtained by experimentation, 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., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Veterinarias

Background: Metal surface immersed in natural or industrial waters undergo a sequence of processes in time and space that lead to the formation of biological and inorganic (scaling) deposit adhesion of different microorganisms (bacteria, microalgae, fungi) on the metal surface through extracellular polymeric substances, causing microbiologically influenced corrosion. The biofilm formation and microbiologically influenced corrosion impact on economic interests and after inorganic corrosion they are the most important problems affecting different industries. The eradication of biofilm in the industry is difficult and costly. Technological importance in the thermoelectric industry by biofilm and biofouling formation lies in energy losses in heat exchanger systems. In the oil industry, problems derived from the presence of biofilms as filter plugging, corrosion in structures storage and distribution of fuel are presented. The aim of this work is to show the different industry cases of microbiologically influenced corrosion: jet aircraft fuel storage tanks and distribution plant, steel plant, thermoelectric industry. The evaluation of microbiologically influenced corrosion and the biofilm formation are investigated. Methods: Microbial counts were performed by conventional techniques. The formation of the biofilm and the attack on the metal surface were studied through scanning electron microscopic techniques. Results: Different results were obtained for each of the industrial environments studied. Conclusion:Strategies to evaluate corrosion problems systems are proposed through microbiological and physical-chemical studies., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

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

Fungi produce pigments and acids, generating particular local conditions which modify the physicochemical properties of materials. The aims of this work are (i) to investigate bioadhesion, foxing production and biofilm formation by Scopulariopsis sp. and Fusarium sp. isolated from document collections under laboratory conditions; (ii) to verify attack on cellulose fibres and (iii) to study the possibility of reducing fungal growth using natural products. Biofilm formation and extracellular polymeric substance (EPS) production by fungi were demonstrated in laboratory assays and by scanning electron microscopy (SEM) observations. The biocidal activity of two essential oils of Origanum vulgare L. and Thymus vulgaris L. was evaluated using the microatmosphere method. SEM observations showed that these strains were able to attach to paper and form biofilms, causing damage on them, which demonstrates the biodeterioration ability of these microorganisms. Scopulariopsis sp. and Fusarium sp. isolated from paper books showed the formation of fox-like reddish-brown colour spots, attack to the paper structure and pigment production on aged paper samples. The strains tested produced a decrease in the pH of one unit. This would substantiate the effect of the strains in paper biodeterioration. The microatmosphere method showed that volatile compounds of the essential oils have antifungal activity., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Veterinarias, Facultad de Ciencias Naturales y Museo

Biocorrosion and biofouling processes are mediated by microorganisms adhered to the metal surfaces or embedded in a gelatinous matrix called biofilm. Biofilms affect the interaction between metals and the environment not only in deleterious processes like corrosion but also in several biological processes applied to materials recovery and handling. The growth of the microorganisms capable to induce biocorrosion is conditioned by favorable environmental conditions. However, the chemical agents generally used to prevent or protect metallic structures from biocorrosion are highly toxic and after use can have a negative impact on the environment. Four different approaches developed in our laboratory to prevent and control biocorrosion but minimizing the environmental impact, are successively presented in this paper: a) the use of ozone as an environmentally friend biocide for cooling water systems; b) the assay of the effectiveness of natural biocides on planktonic and sessile bacteria; c) the potential use of film forming corrosion inhibitors; d) the use of innovative preventing substances., Los procesos de biocorrosión y biofouling están mediados por microorganismos que adhieren a las superficies metálicas embebidos en una matriz gelatinosa llamada biofilm. Los biofilms afectan a la interacción entre metales y el medio ambiente, no solo a través de procesos deletéreos tales como la corrosión sino, también, en el manipuleo de diversos materiales. El crecimiento de los microorganismos capaces de inducir biocorrosión esta condicionado por un medio ambiente favorable. Sin embargo, generalmente, los agentes químicos usados para prevenir o proteger las estructuras metálicas de la biocorrosión son altamente tóxicos y su uso puede tener un impacto negativo para el ambiente. En este trabajo se presentan cuatro vías diferentes, desarrolladas en nuestro laboratorio, para prevenir y controlar la biocorrosión minimizando el impacto ambiental: a) uso del ozono en sistemas de enfriamiento de agua; b) ensayos de efectividad de biocidas naturales sobre bacterias sésiles y planctónicas; c) uso de inhibidores de corrosión formadores de film; d) uso de nuevas sustancias preventivas., Facultad de Ciencias Exactas

The aim of this paper was the control of aerobic and anaerobic bacterial biofilms formation on metal surfaces of industrial interest such as stainless steel and mild steel. A natural biocida obtained of an aqueous extract of seeds of black mustard (Brassica nigra) and mixtures of immunoglobulins IgA, IgG, and IgM were used. Microscopic techniques like scanning electron microscopy (SEM) and epifluorescens microscopy were used for observing bacterial adhesion of the metal surfaces. A marked inhibition of bacterial adherence was observed when an immunoglobulin film was formed on the metal surface. When the natural biocide was used, an important decrease in the number of microorganisms in the biofilms was observed.El objetivo del presente trabajo fue controlar la formación de películas bacterianas, constituidas por bacterias aeróbicas y anaeróbicas sobre superficies de interés industrial, tales como aceros inoxidables y acero al carbono. Se utilizó un biocida natural obtenido de un extracto acuoso de semillas de mostaza negra, Brassica nigra, y sustancias de origen biológico (mezcla de inmunoglobulinas: IgA, IgG e IgM). Para observar la adherencia bacteriana a las superficies metálicas se empleó el microscopio electrónico de barrido (MEB) y el microscopio de epifluorescencia. Se observó una marcada inhibición de la adherencia bacteriana en las diferentes condiciones experimentales ensayadas, utilizando la solución de inmunoglobulinas. Se advirtió una disminución importante en el número de microorganismos formadores de las biopelículas cuando se utilizó el biocida natural.

Cooling water treatment requires effective, environmentally-safe biocides compatible with system operation. The unique combination of high biocidal activity during use with no toxic discharge, could render dissolved ozone a safe biocide for cooling water treatment. Planktonic and sessile cells of Pseudomonas fluorescens (a frequent microbial contaminant of industrial systems) were used in this work to assess the biocidal effectiveness of ozone. Dissolved ozone showed to be effective at concentrations between 0.1 and 0.3 ppm, to eliminate completely the levels of planktonic cells used in this paper (10 7 –10 8 cell/ml) within a range of contact times between 10 and 30 min. However, ozone at 0.15 ppm was only able to diminish sessile cell population by two or three orders of magnitude. This minor biocidal effectiveness of ozone against bacterial biofilms is discussed in this paper, taking into account recent concepts on structure and dynamics of biofilms. Different metallic substrata were assayed to verify if there was any effect of metal nature on the biocidal action. Open circuit potentials vs. time experiments and potentiodynamic polarization curves were made for assessing the effect of dissolved ozone on the corrosion behavior of the metals tested.

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.

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

Documentary heritage is permanently subject to suffering from physical, chemical, and/or biological alterations. Biological deterioration by microorganisms (bacteria and fungi) causes undesirable changes on material properties. Microorganisms affect different organic, natural or synthetic substrates (cellulose, polycarbonates), metals, and compounds of optical and magnetic devices (CD, VHS). Paper made by vegetal fibers, functional additives (glue, optical polishers, consolidating agents), and inks with organic bindings are used as sources of nutrients. The environmental microorganisms that formthe microbial charge of indoor air at repositories (archives, libraries) storing cultural heritage can deteriorate the different supports of heritage importance and affect human health as allergies and skin affections. The aims of this research were to study microbial contamination of the environment and its influence on biodeterioration by the biofilm formation and to analyze the relationship between environment microbiota and biofilm formation in materials stored at three archives in Argentina and in two repositories of the National Archive of the Republic of Cuba., Facultad de Ciencias Exactas

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%.