title: 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.
authors.affiliation: Research Centre of the Slovenian Academy of Sciences and Arts, Karst Research Institute, Titov trg 2, 6230, Postojna, Slovenia, janez.mulec@guest.arnes.si.
authors.forename: Janez
authors.initials: J
authors.lastname: Mulec
authors.forename: Václav
authors.initials: V
authors.lastname: Krištůfek
authors.forename: Alica
authors.initials: A
authors.lastname: Chroňáková
authors.forename: Andreea
authors.initials: A
authors.lastname: Oarga
authors.forename: Josef
authors.initials: J
authors.lastname: Scharfen
authors.forename: Martina
authors.initials: M
authors.lastname: Šestauberová
mesh_terms: D002244:Carbon / Q000032:analysis; D017523:Croatia; D004269:DNA, Bacterial / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D017753:Ecosystem; D019015:Geologic Sediments / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000032:analysis; D009094:Mud Therapy; D058974:Phylogeography; D016133:Polymerase Chain Reaction; D020560:Proteobacteria / Q000145:classification* / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012988:Soil Microbiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013855:Thiobacillus / Q000145:classification* / Q000302:isolation & purification; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D019216:Metals, Heavy; D002244:Carbon