317 research outputs found
Biofouling of crypts of historical and architectural interest at la Plata Cemetery (Argentina)
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
XPS characterization of (copper-based) coloured stains formed on limestone surfaces of outdoor Roman monuments
Limestone basements holding bronzes or other copper alloys artefacts such as sculptures, decorations and dedicatory inscriptions are frequently met both in modern and ancient monuments. In outdoor conditions, such a combination implies the corrosion products of the copper based alloy, directly exposed to rainwater, will be drained off and migrate through the porous surfaces, forming stains of different colours and intensities, finally causing the limestone structures to deteriorate
Chemical composition of Desulfovibrio desulfuricans lipid A
Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica
Characterization of the wood mycobiome of Vitis vinifera in a vineyard affected by Esca. Spatial distribution of fungal communities and their putative relation with leaf symptoms
Original ResearchEsca is a disease complex belonging to the grapevine trunk diseases cluster. It
comprises five syndromes, three main fungal pathogenic agents and several symptoms,
both internal (i.e., affecting woody tissue) and external (e.g., affecting leaves and
bunches). The etiology and epidemiology of this disease complex remain, in part,
unclear. Some of the points that are still under discussion concern the sudden
rise in disease incidence, the simultaneous presence of multiple wood pathogens in
affected grapevines, the causal agents and the discontinuity in time of leaf symptoms
manifestation. The standard approach to the study of esca has been mostly through
culture-dependent studies, yet, leaving many questions unanswered. In this study, we
used Illumina R
next-generation amplicon sequencing to investigate the mycobiome
of grapevines wood in a vineyard with history of esca. We characterized the wood
mycobiome composition, investigated the spatial dynamics of the fungal communities
in different areas of the stem and in canes, and assessed the putative link between
mycobiome and leaf symptoms. An unprecedented diversity of fungi is presented (289
taxa), including five genera reported for the first time in association with grapevines
wood (Debaryomyces, Trematosphaeria, Biatriospora, Lopadostoma, and Malassezia)
and numerous hitherto unreported species. Esca-associated fungi Phaeomoniella
chlamydospora and Fomitiporia sp. dominate the fungal community, and numerous
other fungi associated with wood syndromes are also encountered (e.g., Eutypa spp.,
Inonotus hispidus). The spatial analysis revealed differences in diversity, evenness
and taxa abundances, the unique presence of certain fungi in specific areas of
the plants, and tissue specificity. Lastly, the mycobiome composition of the woody
tissue in proximity to leaves manifesting ‘tiger stripes’ symptoms of esca, as well
as in leaf-symptomatic canes, was highly similar to that of plants not exhibiting any leaf symptomatology. This observation supports the current understanding that leaf
symptoms are not directly linked with the fungal communities in the wood. This work
builds to the understanding of the microbial ecology of the grapevines wood, offering
insights and a critical view on the current knowledge of the etiology of escainfo:eu-repo/semantics/publishedVersio
Geoscience of the built environment: pollutants and materials surfaces
An overview of issues with environmental relevance that arise from the
interaction between pollutants and surfaces of the built environment is presented in this
paper. Two broad perspectives are considered: decay of materials and recording of
pollution characteristics. In relation to the former, we consider the possible implications on
human activities restrictions, materials and morphological options, consumption of
resources and release of pollutants resulting from the alteration of materials, conservation
and restoration procedures. In terms of pollution recording, the interest of the stony
materials as passive monitors of pollution, the question of heterogeneous conditions on
buildings and the interest of qualitative and quantitative studies are highlighted. The
importance of longitudinal studies on new and cleaned surfaces is considered, both for the
understanding of materials decay and for the assessment of pollution conditions. The use of
tracers to record the characteristics of pollution sources, interaction with materials and
pathways of pollutants is also discussed. Finally, some recommendations are presented,
based on the issues discussed on this paper that might be relevant for environmental
management programs, including environmental education.Fundação para a Ciência e Tecnologia (Portugal)
(programa plurianual das unidades de investigação; PEst-OE/CTE/UI0697/2011)Fundação das Universidades PortuguesaMinisterio de Ciencia e Innovación - Acción Integrada PT2009-007
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