Phototrophic Biofilms on Ancient Mayan Buildings in Yucatan, Mexico

Abstract

Buildings at the important archaeological sites of Uxmal and Kabah, Mexico, are being degraded by microbial biofilms. Phospholipid fatty acid (PLFA) and chlorophyll a analyses indicated that phototrophs were the major epilithic microorganisms and were more prevalent on interior walls than exterior walls. Culture and microscopical techniques showed that Xenococcus formed the major biomass on interior surfaces, but the stone-degrading genera Gloeocapsa and Synechocystis were also present in high numbers. Relatively few filamentous algae and cyanobacteria were detected. The fatty acid analysis also showed that complex biofilms colonize these buildings. Circular depressions observed by scanning electron microscopy (SEM) on stone and stucco surfaces beneath the biofilm corresponded in shape and size to coccoid cyanobacteria. SEM images also demonstrated the presence of calcareous deposits on some coccoid cells in the biofilm. Phototrophic biofilms may contribute to biodegradation by (1) providing nutrients that support growth of acid-producing fungi and bacteria and (2) active "boring" behavior, the solubilized calcium being reprecipitated as calcium carbonate.

Quorum sensing in Cyanobacteria: N-octanoyl-homoserine lactone release and response, by the epilithic colonial cyanobacterium Gloeothece PCC6909

“…Studies of intra-and intercellular signal systems of epilithic colonial cyanobacteria, such as Gloeothece, may prove to be important in understanding various adaptive capabilities of cyanobacteria to stressful conditions, such as nutrient deficiency (Schwarz and Forchhammer, 2005). Furthermore, such information may be significant to an understanding of biofilm formation involving Gloeothece and its interaction with other microorganisms that leads to the deterioration of buildings and monuments, a current issue concerned in the preservation of important archaeological sites (Ortega-Morales et al, 2000;Crispim et al, 2003). 'Quorum sensing', a cell density-dependent mechanism of intercellular communication generally associated with physiological changes that occur at high cell densities (Fuqua et al, 2001), occurs in a number of organisms (Kleerebezem et al, 1997;Whitehead et al, 2001;Nickerson et al, 2006;Sprague and Winans, 2006).…”

Heterotrophic Pioneers Facilitate Phototrophic Biofilm Development

“…Phototrophic biofilms are formed on surfaces in a range of terrestrial and aquatic environments (e.g., [7,15,20]). The major energy source in these biofilms is photosynthesis.…”

Biofilm Formation by the Fungal Pathogen Candida albicans : Development, Architecture, and Drug Resistance

“…Biofilms are studied in a wide range of scientific disciplines including biomedicine, water engineering, and evolutionary biology (3,10,14,15,22,23,33). Biofilms are the most common mode of bacterial growth in nature and are also important in clinical infections, especially due to the high antibiotic resistance associated with them (4,11,46).…”