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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

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.

Comparative assessment of atmospheric and microbiological deterioration of constructional material of a church, which is part of the Colombian cultural heritage was made using different microbiological and surface analytical techniques complemented by electron microscopy. The main constructional material of the church of Veracruz in the urban area of the city of Medellin is peridotite, an ultramafic igneous rock containing >90% of iron and magnesium minerals such as olivine and pyroxene. Assessment showed that the atmospheric characteristics in the city of Medellin are only slightly aggressive, suggesting that weathering would not be the main cause of decay of the structural material. The main microorganisms isolated from the facade of the church were heterotrophic bacteria and fungi, and phototrophic microalgae and cyanobacteria. Lichens and mosses were also found colonizing the rock. Experimental evidence suggests that deterioration of the peridotite is mainly due to acidifying bacteria and other microbial contaminants and that atmospheric factors would only play a secondary role in the decay.

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.

Many of the monuments of the Mayan civilization are suffering deterioration caused by environmental factors (high temperatures and relative humidities), increasing contamination from natural and anthropogenic sources, and by the action of micro- and macro-biological communities. Archaeological sites and historical monuments in the Mayan area were constructed with different limestones which offer different resistances to degradation by the various types of contamination. Two different sampling sites were chosen at the archaeological site of Uxmal in the Yucatan Peninsula, Mexico. Heterotrophic bacteria, cyanobacteria and different fungi were isolated and classified taxonomically. The other archaeological site chosen for this study was the fortress of Tulum, located at the side of the Caribbean Sea and exposed to chloride of marine spray and sand erosion. In this case, heterotrophic aerobic and anaerobic bacteria, cyanobacteria and fungi were isolated from the four sampling areas selected. In both archaeological sites crust deposits were observed by using light microscopy, SEM and ESEM. Surface analyses were made by means of EDAX and electron microprobe. Possible mechanisms of stone decay, based on the type of microorganisms isolated, the physico-chemical characteristics of the constructional materials and environmental factors are discussed.

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.

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

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

Natural products obtained from plants with biocidal activity represent an alternative and useful source in the control of biodeterioration of documentary heritage, without negative environmental and human impacts. In this work, we studied the antimicrobial activity of seven essential oils against microorganisms associated with the biodeterioration of documentary heritage. The essential oils were obtained by steam distillation. The antimicrobial activity was analyzed using the agar diffusion method against 4 strains of fungi and 6 bacterial strains isolated fromrepositories air and documents of theNational Archive of the Republic of Cuba and theHistorical Archive of theMuseum of La Plata, Argentina. Anise and garlic oils showed the best antifungal activity at all concentrations studied, while oregano oil not only was effective against fungi tested but also prevented sporulation of them all. Orange sweet and laurel oils were ineffective against fungi. Clove, garlic, and oregano oils showed the highest antibacterial activity at 25% against Enterobacter agglomerans and Streptomyces sp., while only clove and oregano oils were effective against Bacillus sp. at all concentrations studied. This study has an important implication for the possible use of the natural products from plants in the control of biodeterioration of documentary heritage., Facultad de Ciencias Exactas

Cemeteries are part of the cultural heritage of urban communities, containing funerary crypts and monuments of historical and architectural interest. Efforts aimed at the conservation of these structures must target not only the abiotic stresses that cause their destruction, such as light and humidity, but also biofouling by biotic agents. The purpose of this study was to assess the development of biofouling of several historically and architecturally valuable crypts at La Plata Cemetery (Argentina). Samples obtained from the biofilms, lichens, and fungal colonies that had developed on the marble surfaces and cement mortar of these crypts were analyzed by conventional microbiological techniques and by scanning electron microscopy. The lichens were identified as Caloplaca austrocitrina, Lecanora albescens, Xanthoparmelia farinosa and Xanthoria candelaria, the fungi as Aspergillus sp., Penicillium sp., Fusarium sp., Candida sp. and Rhodotorula sp., and the bacteria as Bacillus sp. and Pseudomonas sp. The mechanisms by which these microorganisms cause the aesthetic and biochemical deterioration of the crypts are discussed. © 2011 Elsevier Masson SAS. Fil: Guiamet, Patricia Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina Fil: Rosato, Vilma Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica, La Plata; Argentina. Universidad Tecnológica Nacional; Argentina Fil: Gómez de Saravia, Sandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Coto García, Ana María. Universidad Politécnica de Madrid; España Fil: Moreno, Diego A.. Universidad Politécnica de Madrid; España

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.

Biofouling is the colonization of man-made substrata by sessile organisms. The aim of this paper is to evaluate the performance of two antifouling saturated copper coating. Bioassays were can-ied out at a harbor in Argentine (38°02'S-57°32'W). During six months, one series of pipes and panels were removed monthly to estimate the recruitment of macro and microfouling species and immediately replaced by clean ones. Another series was removed from the beginning of exposure to monitor the development of the established community (accumulative pipes and panels along six months). Data obtained from control (without a saturated copper coating) and saturated-copper coated pipes and panels were compared in order to estimate performance of the coating. One of two saturated copper coating demonstrated a good effect antifouling., El biofouling es la colonización por organismos sésiles en sistemas de sustratos hechos por el hombre. El objetivo fue evaluar el efecto antifouling de dos cubiertas saturadas de cobre. Los estudios se llevaron a cabo en un puerto de la Argentina (38°02’S-57°32’W). Durante seis meses, una serie de caños y paneles fueron removidos mensualmente para estimar el reclutamiento de las especies del macro y microfouling, y fueron sustituidos inmediatamente por caños y paneles limpios. La otra serie de caños y paneles fueron removidas desde el inicio de la exposición en forma acumulativa durante los seis meses, para seguir el desarrollo de la comunidad. Los datos obtenidos de los controles sin cubierta y de los caños y paneles con las cubiertas saturadas de cobre fueron comparados para estimar el comportamiento antifouling de las mismas. Una de las dos cubiertas saturadas de cobre demostró un buen efecto antifouling., Facultad de Ciencias Naturales y Museo