Microbiology of Healing Mud (Fango) from Roman Thermae Aquae Iasae Archaeological Site (Varaždinske Toplice, Croatia)

Abstract

We found well-preserved, rocky artefacts that had been buried in the healing mud (fango) for more than 1,500 years at the Roman archaeological site at Varaždinske Toplice. This Roman pool with fango sediments and artefacts is fed from hot sulphidic springs. The fango exhibited nearly neutral pH, a high level of organic C, an elevated concentration of heavy metals and a high total microbial biomass, greater than 10(8) cells per gram of dry weight. The dominant microbes, assessed by molecular profiling (denaturing gradient gel electrophoresis), were affiliated with Thiobacillus, Sulfuricurvum, Polaromonas, and Bdellovibrio. Polymerase chain reaction screening for microbial functional guilds revealed the presence of sulphur oxidizers and methanogens but no sulphate reducers. The dominance of four Proteobacterial classes (α-, β-, δ- and ε-Proteobacteria) was confirmed by fluorescence in situ hybridisation; Actinobacteria were less abundant. Cultivable bacteria represented up to 23.4 % of the total bacterial counts when cultivation media was enriched with fango. These bacteria represented the genera Acinetobacter, Aeromonas, Arthrobacter, Comamonas, Ewingella, Flavobacterium, Pseudomonas, Rahnella and Staphylococcus. This study showed that the heterogeneous nature of fango at neutral pH created various microniches, which largely supported microbial life based on sulphur-driven, autotrophic denitrification.

Characterization of soil bacterial, archaeal and fungal communities inhabiting archaeological human-impacted layers at Monte Iato settlement (Sicily, Italy)

“…Our data, along with those of other surveys of soil bacterial communities at archaeological sites using high-throughput sequencing techniques 6 , demonstrate that the taxonomic composition of soil bacterial communities concurs with that described as common in the soil environment 24 , 25 and evidence that bacterial diversity in these environments is not dominated by “rare” microbial taxa. However, archaeological sites have been described as potential sources of novel microbial species 5 , 9 . In the present study, OTUs affiliated to genus Pseudomonas were shown to be the most abundant ones and the main responsible for dissimilarity in soil bacterial community structure among the three layers.…”

“…Previous studies have confirmed the presence of Pseudomonas in archaeological remains. In a culture-dependent study of the mud from a Roman thermae, strains classified as Pseudomonas were reported 9 . Xu, et al .…”

“…The coming together of archaeology and microbiology promises to revolutionize the analysis and interpretation of archaeological deposits 1 . In this way, the few existing works studying the microbial communities associated with archaeological samples such as dental calculi 2 , bones 3 , different kinds of organic remains 4 , anthropogenically-impacted soils 5 – 8 and mud 6 , 9 have confirmed the efficacy of this new direction of analysis in archaeology that may impact on the formulation of theories and our understanding of past events 1 .…”

Evaluation of MALDI-TOF mass spectrometry and MALDI BioTyper in comparison to 16S rDNA sequencing for the identification of bacteria isolated from Arctic sea water

“…Uhlik et al [23] isolated 54 cultured biphenyl-metabolizing bacteria from contaminated soil and obtained high concordance between MB and 16S rDNA analysis at the genus level only. Even if Mulec et al [47] did not compare MB identification with other methods, their work indicated that only 40% of the bacterial strains isolated from a thermal mud were identified by MB.…”

Microbiology Meets Archaeology: Soil Microbial Communities Reveal Different Human Activities at Archaic Monte Iato (Sixth Century BC)

“…For example, on a geological scale, microbiological data can contribute to the understanding and reconstruction of past climatological, environmental, and sedimentary conditions. Moreover, on the time scales of human history and archaeology, microbiological data can contribute to unraveling human cultural habits, microbe-related human diseases, and alterations in cultural artifacts due to biochemical reactions [5]. For example, microbiological studies in archaeological contexts focused on pathogens and on the abundance of microbial spores or coprophilous microorganisms ([3] and references therein).…”