An overview of techniques for the characterization and quantification of microbial colonization on stone monuments

Abstract

Biodeterioration can be defined as any undesired change of the properties of a material caused by biological activity of living organisms. The biodeterioration of stone materials is related to the production of pigments (aesthetic action), to cell metabolism (biochemical action) and to the mechanical action of the biomass colonizing the material during its growth (physical action). Quantification of the sessile biomass and characterization of microbial communities colonizing stone are essential first steps to ensure the diagnosis of biodeterioration processes and to implement control strategies and appropriate treatment. Different destructive and non-destructive approaches can be used to sample stone specimens from monuments: scraping, swab using, and cutting. Different analytical methods can be used depending on the type of microorganism sought: determination of chlorophyll content and color analysis for pigmented microorganisms; measurement of in situ physiological activity of surface microcolonies by applying fluorogenic substrate analogues or confocal laser scanning microscopy observations after CTC staining for active biomass; scanning or transmission electron microscopy observation for biofilm visualization; enzymelinked immunosorbent assay for the investigation of both microorganisms that can and cannot be cultured; classical microbiological methods, which consist in cultivation of microorganisms on synthetic media; and molecular methods for the study of microbial biodiversity based on the polymorphism of molecular markers using PCR, hybridization, classical or high throughput sequencing. The aim of this review is to present basics of the different biodeterioration mechanisms and to focus on the main techniques that can be used to characterize and quantify the biodeterioration biomass.

Cambios en la composición de la comunidad fúngica de biopelículas sobre roca calcárea a través de una cronosecuencia en Campeche, México

“…Meanwhile, the young biofilm was located at an approximate distance of 10.5 kilometers from the other biofilms and had a visible although incipient colonization of microorganisms. Microclimatic differences present at each site may contribute towards the formation of a unique and particular mycobiota (Mihajlovski et al, 2014). Our results differed from those reported for sandstone, in which no differences in eukaryotic composition were found between fresh and young biofilms (Lan et al, 2010).…”

“…Although the intrinsic characteristics of rock, such as its mineral composition, porosity and roughness, have been reported to influence the colonization of microbial communities (Guillitte, 1995;Burford et al, 2003;Lan et al, 2010), the study of Tomaselli et al (2000) did not find a relationship among existing organisms and the petrographic characteristics of rock. In this study, the high values of species richness and diversity may be attributed to favorable environmental factors in the subtropics (Table 1) and time elapsed since initial colonization (Gaylarde and Gaylarde, 2005;Mihajlovski et al, 2014).…”

“…The colonization of lithic substrates by microbial communities is influenced by the properties of the substrate, such as porosity, surface roughness and mineralogical composition -bioreceptivity-(see review in Miller et al, 2012), in addition to climate and microclimatic conditions (Guillitte, 1995;Ortega-Morales et al, 1999;Gaylarde and Gaylarde, 2005;Barberousse et al, 2006). Furthermore, communities of microorganisms growing on lithic substrates, including fungi, may respond differentially to environmental conditions over time based on their ecophysiological requirements (Scheerer et al, 2009;Mihajlovski et al, 2014).…”

The influence of structural organization of epilithic and endolithic lichens on limestone weathering

“…Biogeophysical and biogeochemical processes at the rock surface have been ascribed to the attachment and penetration of epilithic and endolithic lichens, and their release of primary and secondary metabolites with acidic and chelating functions, respectively (Adamo and Violante, 2000;Chen et al, 2000;Favero-Longo et al, 2011;Salvadori and Casanova Municchia, 2016). Advances in microscopic techniques have progressively supported a deeper characterization of lichen structures and associated microbes at the rock interface and their spatial interactions with microstructural features of the substrate and its mineral constituents (De los Ríos and Ascaso, 2005;Favero-Longo et al, 2005;McIlroy de la Rosa et al, 2012;Casanova Municchia et al, 2014;Mihajlovski et al, 2015). Advanced spectroscopies have allowed the localization and characterization of chemical changes in minerals affected by lichen metabolites (Wierzchos and Ascaso, 1994;Barker and Banfield, 1996) and the detection at the interface of secondary minerals, including clays and biomineralization products (Wierzchos and Ascaso, 1998;Edwards et al, 2003;Villar et al, 2004).…”

Biodeterioration of Stone Monuments a Worldwide Issue

“…These are very simple and provide information only on organisms capable of growth under artificial laboratory conditions. However, in order to carry out proper conservation actions, it is necessary to know the complete composition of microbial communities and their activity, as well explained in the review recently published [1]. Researcher's abilities to elucidate the biogeophysical and biogeochemical mechanisms of complex biodeterioration processes occurring at monumental sites have been greatly revolutionized by the use of molecular, physical and highly sophisticated so called high throughput next generation sequencing techniques.…”