|Opis:||The object of this work was the industrial wastewater from the artificial lake situated in the urban environment, where the population is concerned, especially during the summer, by frequent foaming and opacity of the lake water. With the purpose of investigating microbial community of the lake, we have taken water and sediment samples from five sampling points representing different geographical areas of the lake. The sampling was performed in summer of 2013. Selected physicochemical characteristics have been also analyzed. On nutrient agar, we have isolated 71 morphologically different isolates. We have described all the isolates with phenotypic and molecular-biological approaches. After analysis of 16S rRNA gene sequences, we have identified 20 different bacterial genera from 16 families. The 16S rRNA gene sequence of one isolate had only 96.2 % identity to its closest reference species, which is why we have further investigated this isolate with phenotypic approaches and by analysis of the entire genome sequence. Based on the results, the strain was described and published as a novel bacterial species Paenibacillus aquistagni 11T. By analyzing resistance to clinically important antibiotics among isolates from Enterobacteriaceae family, and genera Acinetobacter and Pseudomonas, we have uncovered resistance to ampicillin, with 14.3 % of the Enterobacteriaceae strains also being resistant to chloramphenicol. Isolates obtained from the most foam-prone sampling site and identified as Acinetobacter sp., Pseudomonas otitidis or Bacillus sp. have also created a stable foam on the surface of a complex medium under laboratory conditions. After the analysis of physico-chemical properties of water, we have concluded that the highest metal concentration is present in sampling site 5. The analysis identified the capability of isolates from this point for growing in medium with 300 mg/L Fe, for 73 % of them for growing in the presence of 900 mg/L Fe and for one of them even with the presence of 1500 mg/L Fe. Tolerance to 300 mg/L Mn was confirmed for 91 % of strains and to 1500 mg/L Mn for 37 % of tested strains. Using the Ion Torrent technology and analysis based on seven variable regions of 16S rRNA gene sequences, we have also directly analyzed the composition of microbial community from the same five sampling points of the lake as we performed the growing and isolation of strains. In water samples 1, 3 and 4 operational taxonomic units (OTU) from the Prochlorococcacea family represented the highest number, in sample 2 from Sphingomonadaceae and in sample 5 from Gallionellacea. In sediment 1, OTU from the Rhodobacteraceae had the highest number, in sediment 2 from Sphingomonadaceae, in sediment 3 from Desulfobacteraceae, in sediment 4 from Pseudomonadaceae, and in sample sediment 5 from Nostocaceae. A comparison of identified bacterial families by indirect approach and next generation sequencing technology showed the highest coverage for water sample 2 (57.2 %), a bit lower for water sample 1 (21.8 %), water 3 (20.0 %) and water 4 (14.5 %) and the lowest for water sample 5 (1.2 %). The same type of comparison showed the highest coverage for samples sediment 4 (74.0 %) and sediment 2 (57.4 %), substantially lower for samples sediment 3 (10.2 %) and sediment 1 (14.0 %) and the lowest as in the case of water samples for the samples from sampling point 5 (2.4 %).
Using the analysis of principal components, we have analyzed in the structure of reduced space of three principal factors the influence of physicochemical properties on the presence of bacterial families in samples. We have detected an important link between the pH, the content of Mg, Na, Cu, Fe, Mn, Zn in the water and families Gallionellaceae, Burkholderiaceae, Eubacteriaceae, Methylophilaceae, Ferrovaceae. In sediments, the prevailing link was between As, Cd, Co, Cu, Fe, Mn, Ni, Zn, and families Nostocaceae, Ferrovaceae, Gallionellaceae, Acetobacteraceae, Acidobacteriaceae.|