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The enchytraeid fauna of the Őrség National Park (Western Hungary), hitherto unknown, was investigated in this study. 14 enchytraeid genera including 47 species and one other annelid worm (Hrabeiella periglandulata) were identified. One enchytraeid species was found to be new to science and is described in this paper as Fridericia zicsii sp. nov. The new species is distinguishable based on both morphological characters and molecular data (mitochondrial cytochrome c oxidase subunit I, nuclear histone 3 genes and nuclear ribosomal ITS region sequences) from similar species. The enchytraeid fauna of Őrség NP indicated well the subalpine nature of this area. The most species-rich site was the hay meadow (32 species) and interestingly, the species number in the Sphagnum bog of Szőce was unusually high (19 species).

The enchytraeid fauna of Kőszeg Mountains (Western Hungary and Eastern Austria), hitherto unknown, was investigated in this study. Fifteen enchytraeid genera including 59 species and two other annelid worms (Hrabeiella periglandulata Pižl & Chalupský, 1984 and Parergodrilus heideri Reisinger, 1925) were identified. The latter is a new record for Hungary. One enchytraeid species, proved to be new to science, is described in this paper as Fridericia szoevenyii sp. nov. The new species is distinguished from similar species on the basis of both morphological characters and molecular data (mitochondrial cytochrome c oxidase subunit I and nuclear histone 3 gene sequences). Based on the presence of subalpinealpine species, the enchytraeid fauna of Kőszeg Mountains is similar to that of Rax Mountains (Northern Alps, Austria). The two most species-rich sites were the alder carr at a creekside near Paprét (33 species) and a mesophile montane hay meadow at Steirer Houses (27 species). Interestingly, a mixed forest with dense underwood of Vaccinium myrtillus harbored only a single species. [ABSTRACT FROM AUTHOR]

Growing human population and increasing urbanization call for the need for proper wastewater treatment to reduce environmental pollution and reduce the excess use of natural resources. During the collection of municipal wastewater, the rapid aerobic respiration often causes oxygen depletion and anaerobic conditions in the sewer system resulting in the production of malodorous compounds. The odor problems may lead to public complaints, or in the case of the sewage workers the released volatile compounds even cause serious health hazards. Therefore, microbes have a dual contribution in the urban water cycle, since they have a decisive role in wastewater treatment and the removal of pollutants, but they can also cause problems in the artificial environment. In this review, I would like to summarize the processes underlying the generation of the bad smell associated with sewage and wastewater or with the collection and treatment infrastructure, tracking the way from the households to the plants, including the discussion of processes and possible mitigation related to the released hydrogen sulfide, volatile organics and other compounds., (© 2024. The Author(s).)

Birch tar was added to polylactide (PLA) and polycaprolactone (PCL) to create films with antimicrobial properties. After incubating the films for seven days in lake water, the diversity of bacterial communities developed on the surfaces of PCL and PLA with embedded birch tar (1 %, 5 %, and 10 %, w/w) was assessed with amplicon sequencing of the 16S rRNA gene on a MiSeq platform (Illumina). Notably, Aquabacterium and Caulobacter were more abundant at the surface of PCL compared to PLA (13.4 % vs 0.2 %, p < 0.001 and 9.5 % vs 0.2 %, p < 0.001, respectively) while Hydrogenophaga was significantly more abundant at the surface of PLA compared to PCL (6.1 % vs 1.8 %, p < 0.01). Overall, lower birch tar concentrations (1 % and 5 % on both polymers) stimulated bacterial diversity in biofilms compared to the control. The number of reeds assigned to Flavobacterium and Aquabacterium showed a rising trend with the increase of birch tar concentration on the surface of both polymers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The physical and chemical characteristics of the bedrock, along with the geological and hydrological conditions of karst caves may influence the taxonomic and functional diversity of prokaryotes. Most studies so far have focused on microbial communities of caves including only a few samples and have ignored the chemical heterogeneity of different habitat types such as sampling sites, dripping water, carbonate precipitates, cave walls, cave sediment and surface soils connected to the caves. The aim of the present study was to compare the morphology, the composition and physiology of the microbiota in caves with similar environmental parameters (temperature, host rock, elemental and mineral composition of speleothems) but located in different epigenic karst systems. Csodabogyós Cave and Baradla Cave (Hungary) were selected for the analysis of bacterial and archaeal communities using electron microscopy, amplicon sequencing, X-ray diffraction, and mass spectroscopic techniques. The microbial communities belonged to the phyla Pseudomonadota, Acidobacteriota, Nitrospirota and Nitrososphaerota, and they showed site-specific variation in composition and diversity. The results indicate that morphological and physiological adaptations provide survival for microorganisms according to the environment. In epigenic karst caves, prokaryotes are prone to increase their adsorption surface, cooperate in biofilms, and implement chemolithoautotrophic growth with different electron-donors and acceptors available in the microhabitats., (© The Author(s) 2023. Published by Oxford University Press on behalf of FEMS.)

The important roles of bacterial outer membrane vesicles (OMVs) in various diseases and their emergence as a promising platform for vaccine development and targeted drug delivery necessitates the development of imaging techniques suitable for quantifying their biodistribution with high precision. To address this requirement, we aimed to develop an OMV specific radiolabeling technique for positron emission tomography (PET). A novel bacterial strain (E. coli BL21(DE3) ΔnlpI, ΔlpxM) was created for efficient OMV production, and OMVs were characterized using various methods. SpyCatcher was anchored to the OMV outer membrane using autotransporter-based surface display systems. Synthetic SpyTag-NODAGA conjugates were tested for OMV surface binding and 64 Cu labeling efficiency. The final labeling protocol shows a radiochemical purity of 100% with a ~ 29% radiolabeling efficiency and excellent serum stability. The in vivo biodistribution of OMVs labeled with 64 Cu was determined in mice using PET/MRI imaging which revealed that the biodistribution of radiolabeled OMVs in mice is characteristic of previously reported data with the highest organ uptakes corresponding to the liver and spleen 3, 6, and 12 h following intravenous administration. This novel method can serve as a basis for a general OMV radiolabeling scheme and could be used in vaccine- and drug-carrier development based on bioengineered OMVs., (© 2023. The Author(s).)

Seasonal environmental variation is a leading driver of microbial planktonic community assembly and interactions. However, departures from usual seasonal trends are often reported. To understand the role of local stressors in modifying seasonal succession, we sampled fortnightly, throughout three seasons, five nearby shallow soda lakes exposed to identical seasonal and meteorological changes. We characterised their microeukaryotic and bacterial communities by amplicon sequencing of the 16S and 18S rRNA gene, respectively. Biological interactions were inferred by analyses of synchronous and time-shifted interaction networks, and the keystone taxa of the communities were topologically identified. The lakes showed similar succession patterns during the study period with spring being characterised by the relevance of trophic interactions and a certain level of community stability followed by a more dynamic and variable summer-autumn period. Adaptation to general seasonal changes happened through shared core microbiome of the lakes. Stochastic events such as desiccation disrupted common network attributes and introduced shifts from the prevalent seasonal trajectory. Our results demonstrated that, despite being extreme and highly variable habitats, shallow soda lakes exhibit certain similarities in the seasonality of their planktonic communities, yet local stressors such as droughts instigate deviations from prevalent trends to a greater extent for microeukaryotic than for bacterial communities., (© The Author(s) 2023. Published by Oxford University Press on behalf of FEMS.)

Chemical fertilization has a negative impact on the natural environment. Plant growth-promoting (PGP) rhizobacterial biofertilizers can be a safer alternative to synthetic agrochemicals. In this research, a culture-based method was used to assess the population size of rhizobacteria at the vegetative, flowering, and maturity stages of canola. Rhizobacteria were then isolated from each of the canola growth stages, and their seven PGP traits were determined. The highest abundance of culturable bacteria was found at the vegetative stage of the plants. Furthermore, four out of seven PGP traits were produced by the highest % of isolates at the vegetative stage. In the greenhouse experiment that included six rhizobacterial strains with best PGP traits, the greatest canola growth promotion ability under sterile conditions was observed after the introduction of Bacillus paralicheniformis 2R5. Moreover, under nonsterile conditions, 2R5 significantly increased canola growth. The presence of the trpA, B, C, D, E, F and pstA, and S genes in the 2R5 genome could be associated with canola growth promotion abilities. The chiA and mbtH genes could contribute to 2R5 antifungal activity against fungal pathogens. Moreover, the introduction of 2R5 significantly increased the abundance of the narG, nosZ, nifH, and nirS genes, which can prove that the 2R5 strain may be an important member of the soil bacterial community., (© The Author(s) 2023. Published by Oxford University Press on behalf of FEMS.)

The genus Belliella belongs to the family Cyclobacteriaceae (order Cytophagales , phylum Bacteroidota ) and harbours aerobic chemoheterotrophic bacteria. Members of this genus were isolated from various aquatic habitats, and our analysis based on global amplicon sequencing data revealed that their relative abundance can reach up to 5-10 % of the bacterioplankton in soda lakes and pans. Although a remarkable fraction of the most frequent genotypes that we identified from continental aquatic habitats is still uncultured, five new alkaliphilic Belliella strains were characterized in detail in this study, which were isolated from three different soda lakes and pans of the Carpathian Basin (Hungary). Cells of all strains were Gram-stain-negative, obligate aerobic, rod-shaped, non-motile and non-spore-forming. The isolates were oxidase- and catalase-positive, red-coloured, but did not contain flexirubin-type pigments; they formed bright red colonies that were circular, smooth and convex. Their major isoprenoid quinone was MK-7 and the predominant fatty acids were iso-C 15 : 0 , iso-C 17 : 0 3-OH and summed feature 3 containing C 16 : 1  ω 6 c and/or C 16 : 1  ω 7 c . The polar lipid profiles contained phosphatidylethanolamine, an unidentified aminophospholipid, an unidentified glycolipid, and several unidentified lipids and aminolipids. Based on whole-genome sequences, the DNA G+C content was 37.0, 37.1 and 37.8 mol % for strains R4-6 T , DMA-N-10a T and U6F3 T , respectively. The distinction of three new species was confirmed by in silico genomic comparison. Orthologous average nucleotide identity (<85.4 %) and digital DNA-DNA hybridization values (<38.9 %) supported phenotypic, chemotaxonomic and 16S rRNA gene sequence data and, therefore, the following three novel species are proposed: Belliella alkalica sp. nov. (represented by strains R4-6 T =DSM 111903 T =JCM 34281 T =UCCCB122 T and S4-10), Belliella calami sp. nov. (DMA-N-10a T =DSM 107340 T =JCM 34280 T =UCCCB121 T ) and Belliella filtrata sp. nov. (U6F3 T =DSM 111904 T =JCM 34282 T =UCCCB123 T and U6F1). Emended descriptions of species Belliella aquatica , Belliella baltica , Belliella buryatensis , Belliella kenyensis and Belliella pelovolcani are also presented.

An important challenge in the study of ecosystem function is resolving how plant antiherbivore chemical defence expression may influence plant-associated microbes, and nutrient release. We report on a factorial experiment that explores a mechanism underlying this interplay using individuals of the perennial plant Tansy that vary genotypically in the chemical content of their antiherbivore defenses (chemotypes). We assessed to what extent soil and its associated microbial community versus chemotype-specific litter determined the composition of the soil microbial community. Microbial diversity profiles revealed sporadic effects of chemotype litter and soil combinations. Soil source and litter type both explained the microbial communities decomposing the litter with soil source having a more important effect. Some microbial taxa are related to particular chemotypes, and thus intra-specific chemical variation of a single plant chemotype can shape the litter microbial community. But we found that ultimately the effect of fresh litter inputs from a chemotype appeared to act secondary as a filter on the composition of the microbial community, with the primary factor being the existing microbial community in the soil., (© 2023. The Author(s).)

The objective of this study was to establish and to mathematically describe the phenol degrading properties of a new Acinetobacter towneri CFII-87 strain, isolated from a bioreactor treating landfill leachate. For this purpose, the biokinetic parameters of phenol biodegradation at various initial phenol concentrations of the A. towneri CFII-87 strain have been experimentally measured, and four different mathematical inhibition models (Haldane, Yano, Aiba and Edwards models) have been used to simulate the substrate-inhibited phenol degradation process. The results of the batch biodegradation experiments show that the new A. towneri CFII-87 strain grows on and metabolizes phenol up to 1000 mg/L concentration, manifests significant substrate inhibition and lag time only at concentrations above 800 mg/L phenol, and has a maximum growth rate at 300 mg/L initial phenol concentration. The comparison of the model predictions with the experimental phenol and biomass data revealed that the Haldane, Aiba and Edwards models can be used with success to describe the phenol biodegradation process by A. towneri CFII-87, while the Yano model, especially at higher initial phenol concentrations, fails to describe the process. The best performing inhibition model was the Edwards model, presenting correlation coefficients of R 2  > 0.98 and modelling efficiency of ME > 0.94 for the prediction of biomass and phenol concentrations on the validation datasets. The calculated biokinetic model parameters place this new strain among the bacteria with the highest tolerance towards phenol. The results suggest that the A. towneri CFII-87 strain can potentially be used in the treatment of phenolic wastewaters., (© 2023. The Author(s).)

Bacteria employ secondary metabolism to combat competitors, and xenobiotic metabolism to survive their chemical environment. This project has aimed to introduce a bacterial collection enabling comprehensive comparative investigations of those functions. The collection comprises 120 strains (Proteobacteria, Actinobacteria and Firmicutes), and was compiled on the basis of the broad taxonomic range of isolates and their postulated biosynthetic and/or xenobiotic detoxification capabilities. The utility of the collection was demonstrated in two ways: first, by performing 5144 co-cultures, recording inhibition between isolates and employing bioinformatics to predict biosynthetic gene clusters in sequenced genomes of species; second, by screening for xenobiotic sensitivity of isolates against 2-benzoxazolinone and 2-aminophenol. The co-culture medium of Bacillus siamensis D9 and Lysinibacillus sphaericus DSM 28T was further analysed for possible antimicrobial compounds, using liquid chromatography-mass spectrometry (LC-MS), and guided by computational predictions and the literature. Finally, LC-MS analysis demonstrated N-acetylation of 3,4-dichloroaniline (a toxic pesticide residue of concern) by the actinobacterium Tsukamurella paurometabola DSM 20162T which is highly tolerant of the xenobiotic. Microbial collections enable "pipeline" comparative screening of strains: on the one hand, bacterial co-culture is a promising approach for antibiotic discovery; on the other hand, bioremediation is effective in combating pollution, but requires knowledge of microbial xenobiotic metabolism. The presented outcomes are anticipated to pave the way for studies that may identify bacterial strains and/or metabolites of merit in biotechnological applications., Competing Interests: The authors have declared that no competing interests exist.

In this study, different maize fields cultivated under different management systems were sampled to test corn leaf aphid, Rhopalosiphum maidis , populations in terms of total and endosymbiotic bacterial diversity. Corn leaf aphid natural populations were collected from traditionally managed maize fields grown under high agricultural and natural landscape diversity as well as conventionally treated high-input agricultural fields grown in monoculture and with fertilizers use, hence with low natural landscape diversity. Total bacterial community assessment by DNA sequencing was performed using the Illumina MiSeq platform. In total, 365 bacterial genera were identified and 6 endosymbiont taxa. A high abundance of the primary endosymbiont Buchnera and secondary symbionts Serratia and Wolbachia were detected in all maize crops. Their frequency was found to be correlated with the maize management system used, probably with fertilizer input. Three other facultative endosymbionts (" Candidatus Hamiltonella ", an uncultured Rickettsiales genus, and Spiroplasma ) were also recorded at different frequencies under the two management regimes. Principal components analyses revealed that the relative contribution of the obligate and dominant symbiont Buchnera to the aphid endosymbiotic bacterial community was 72%, whereas for the managed system this was only 16.3%. When facultative symbionts alone were considered, the effect of management system revealed a DNA diversity of 23.3%.

The extreme environmental conditions of the diverse saline inland waters (soda lakes and pans, hypersaline lakes and ponds) of the Carpathian Basin are an advantage for picophytoplankton. The abundance of picophytoplankton in these waters can be up to several orders of magnitude higher than that in freshwater shallow lakes, but differences are also found within different saline water types: higher picophytoplankton abundances were observed in hypersaline lakes compared to humic soda lakes, and their highest numbers were detected in turbid soda lakes. Moreover, their contribution to phytoplankton biomass is higher than that in shallow freshwater lakes with similar trophic states. Based on long-term data, their ratio within the phytoplankton increased with turbidity in the case of turbid soda lakes, while, in hypersaline lakes, their proportion increased with salinity. Picocyanobacteria were only detected with high abundance (>106−107 cells/mL) in turbid soda lakes, while picoeukaryotes occurred in high numbers in both turbid and hypersaline lakes. Despite the extreme conditions of the lakes, the diversity of picophytoplankton is remarkable, with the dominance of non-marine Synechococcus/Cyanobium, Choricystis, Chloroparva and uncultured trebouxiophycean green algae in the soda lakes, and marine Synechococcus and Picochlorum in the hypersaline lakes.

Beside sodium chloride, inland saline aquatic systems often contain other anions than chloride such as hydrogen carbonate and sulfate. Our understanding of the biological effects of salt composition diversity is limited; therefore, the aim of this study was to examine the effect of different anions on the growth of halophilic bacteria. Accordingly, the salt composition and concentration preference of 172 strains isolated from saline and soda lakes that differed in ionic composition was tested using media containing either carbonate, chloride or sulfate as anion in concentration values ranging from 0 to 0.40 mol/L. Differences in salt-type preference among bacterial strains were observed in relationship to the salt composition of the natural habitat they were isolated from indicating specific salt-type adaptation. Sodium carbonate represented the strongest selective force, while majority of strains was well-adapted to growth even at high concentrations of sodium sulfate. Salt preference was to some extent associated with taxonomy, although variations even within the same bacterial species were also identified. Our results suggest that the extent of the effect of dissolved salts in saline lakes is not limited to their concentration but the type of anion also substantially impacts the growth and survival of individual microorganisms., (© 2022. The Author(s).)

Arylamines constitute a large group of industrial chemicals detoxified by certain bacteria through conjugation reactions catalyzed by N -acetyltransferase (NAT) enzymes. NAT homologs, mostly from pathogenic bacteria, have been the subject of individual studies that do not lend themselves to direct comparisons. By implementing a practicable pipeline, we carried out a comparative investigation of 15 NAT homologs from 10 bacteria, mainly bacilli, streptomycetes, and one alphaproteobacterium. The new homologs were characterized for their sequence, phylogeny, predicted structural features, substrate specificity, thermal stability, and interaction with components of the enzymatic reaction. Bacillus NATs demonstrated the characteristics of xenobiotic metabolizing N -acetyltransferases, with the majority of homologs generating high activities. Nonpathogenic bacilli are thus proposed as suitable mediators of arylamine bioremediation. Of the Streptomyces homologs, the NAT2 isoenzyme of S. venezuelae efficiently transformed highly toxic arylamines, while the remaining homologs were inactive or generated low activities, suggesting that xenobiotic metabolism may not be their primary role. The functional divergence of Streptomyces NATs was consistent with their observed sequence, phylogenetic, and structural variability. These and previous findings support classification of microbial NATs into three groups. The first includes xenobiotic metabolizing enzymes with dual acetyl/propionyl coenzyme A (CoA) selectivity. Homologs of the second group are more rarely encountered, acting as malonyltransferases mediating specialized ecological interactions. Homologs of the third group effectively lack acyltransferase activity, and their study may represent an interesting research area. Comparative NAT enzyme screens from a broad microbial spectrum may guide rational selection of homologs likely to share similar biological functions, allowing their combined investigation and use in biotechnological applications. IMPORTANCE Arylamines are encountered as industrial chemicals or by-products of agrochemicals that may constitute highly toxic contaminants of soils and groundwaters. Although such chemicals may be recalcitrant to biotransformation, they can be enzymatically converted into less toxic forms by some bacteria. Therefore, exploitation of the arylamine detoxification capabilities of microorganisms is investigated as an effective approach for bioremediation. Among microbial biotransformations of arylamines, enzymatic conjugation reactions have been reported, including NAT-mediated N- acetylation. Comparative investigations of NAT enzymes across a range of microorganisms can be laborious and expensive, so here we present a streamlined methodology for implementing such work. We compared 15 NAT homologs from nonpathogenic, free-living bacteria of potential biotechnological utility, mainly Terrabacteria , which are known for their rich secondary and xenobiotic metabolism. The analysis allowed insights into the evolutionary and functional divergence of bacterial NAT homologs, combined with assessment of their fundamental structural and enzymatic differences and similarities.

In this study, we examined the effect of salinity and alkalinity on the metabolic potential and taxonomic composition of microbiota inhabiting the sodic soils in different plant communities. The soil samples were collected in the Pannonian steppe (Hungary, Central Europe) under extreme dry and wet weather conditions. The metabolic profiles of microorganisms were analyzed using the MicroResp method, the bacterial diversity was assessed by cultivation and next-generation amplicon sequencing based on the 16S rRNA gene. Catabolic profiles of microbial communities varied primarily according to the alkali vegetation types. Most members of the strain collection were identified as plant associated and halophilic/alkaliphilic species of Micrococcus , Nesterenkonia , Nocardiopsis , Streptomyces (Actinobacteria) and Bacillus , Paenibacillus (Firmicutes) genera. Based on the pyrosequencing data, the relative abundance of the phyla Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes and Bacteroidetes also changed mainly with the sample types, indicating distinctions within the compositions of bacterial communities according to the sodic soil alkalinity-salinity gradient. The effect of weather extremes was the most pronounced in the relative abundance of the phyla Actinobacteria and Acidobacteria. The type of alkali vegetation caused greater shifts in both the diversity and activity of sodic soil microbial communities than the extreme aridity and moisture.

In this paper, three new enchytraeid species (Enchytraeidae, Clitellata) are described from different mountains of Korea: Cognettia koreana sp. n., Henlea bidiverticulata sp. n. and Mesenchytraeus longidiverticulatus sp. n. Validity of these new species was confirmed by comparative morphological and molecular taxonomic analyses (based on ITS, CO1 and H3 sequences). In addition, ten enchytraeid species never recorded before from Korea were found in the studied soil samples: Bryodrilus diverticulatus Černosvitov, 1929, Cernosvitoviella atrata Bretscher, 1903, Cernosvitoviella minor Dózsa-Farkas, 1990, Cognettia lapponica Nurminen, 1965, Cognettia varisetosa (Martinsson, Rota Erséus, 2015), Fridericia cf. sohlenii Rota, Healy Erséus, 1998, Henlea nasuta Eisen, 1878, Marionina clavata Nielsen Christensen, 1961, Marionina communis Nielsen Christensen, 1959, Marionina seminuda Xie Rota, 2001. Morphological observations and new reference DNA sequences are also provided for the above-mentioned species.

Attachment of microorganisms to natural or artificial surfaces and the development of biofilms are complex processes which can be influenced by several factors. Nevertheless, our knowledge on biofilm formation in karstic environment is quite incomplete. The present study aimed to examine biofilm development for a year under controlled conditions in quasi-stagnant water of a hydrothermal spring cave located in the Buda Thermal Karst System (Hungary). Using a model system, we investigated how the structure of the biofilm is formed from the water and also how the growth rate of biofilm development takes place in this environment. Besides scanning electron microscopy, next-generation DNA sequencing was used to reveal the characteristic taxa and major shifts in the composition of the bacterial communities. Dynamic temporal changes were observed in the structure of bacterial communities. Bacterial richness and diversity increased during the biofilm formation, and 9-12 weeks were needed for the maturation. Increasing EPS production was also observed from the 9-12 weeks. The biofilm was different from the water that filled the cave pool, in terms of the taxonomic composition and metabolic potential of microorganisms. In these karstic environments, the formation of mature biofilm appears to take place relatively quickly, in a few months.

In Hungary, which is famous for its thermal baths, according to the regulations, waters are investigated in hygienic aspects with standard cultivation methods. In the present study, two thermal baths were investigated (the well and three different pool waters in both) using cultivation methods, taxon-specific polymerase chain reactions (PCRs), multiplex PCRs and next-generation amplicon sequencing. Mainly members of the natural microbial community of the well waters and bacteria originating from the environment were detected but several opportunistic pathogenic taxa, e.g., Pseudomonas aeruginosa, P. stutzeri, Acinetobacter johnsoni, Acinetobacter baumanni, Moraxella osloensis, Microbacterium paraoxydans, Legionella spp., Stenotrophomonas maltophilia and Staphylococcus aureus were revealed by the applied methods. Pools with charging-unloading operation had higher microscopic cell counts, colony-forming unit (CFU) counts, number of cocci, P. aeruginosa and S. aureus compared to the recirculation systems. Bacteria originating from human sources (e.g., skin) were identified in the pool waters with less than 1% relative abundance, and their presence was sporadic in the pools. Comparing the microbiological quality of the pools based on the first sampling time and the following four months' period it was revealed that recirculation operation type has better water quality than the charging-unloading pool operation from a hygienic point of view.

In this review, I would like to summarize the current knowledge on the microbiology of soda lakes and pans of the Carpathian Basin. First, the characteristic physical and chemical features of these sites are described. Most of the microbiological information presented deals with prokaryotes and algae, but protists and viruses are also mentioned. Planktonic bacterial communities are dominated by members of the phyla Actinobacteria, Bacteroidetes and Proteobacteria; small-sized trebouxiophycean green algae and Synechococcus/Cyanobium picocyanobacteria are the most important components of phytoplankton. Based on the current knowledge, it seems that mainly temperature, salinity, turbidity and grazing pressure regulate community composition and the abundance of individual microbial groups, but the external nutrient load from birds also has a significant impact on the ecological processes., (© 2020. The Author(s).)

During coke production, large volume of effluent is generated, which has a very complex chemical composition and contains several toxic and carcinogenic substances, mainly aromatic compounds, cyanide, thiocyanate and ammonium. The composition of these high-strength effluents is very diverse and depends on the quality of coals used and the operating and technological parameters of coke ovens. In general, after initial physicochemical treatment, biological purification steps are applied in activated sludge bioreactors. This review summarizes the current knowledge on the anaerobic and aerobic transformation processes and describes key microorganisms, such as phenol- and thiocyanate-degrading, floc-forming, nitrifying and denitrifying bacteria, which contribute to the removal of pollutants from coke plant effluents. Providing the theoretical basis for technical issues (in this case the microbiology of coke plant effluent treatment) aids the optimization of existing technologies and the design of new management techniques., (© 2020. The Author(s).)

Occurrence of the smallest phototrophic microorganisms (photoautotrophic picoplankton, APP) in Lake Balaton was discovered in the early 1980s. This triggered a series of systematic studies on APP and resulted in the setting of a unique long-term picoplankton dataset. In this review, we intend to summarize the obtained results and to give a new insight on APP ecology and diversity in Lake Balaton. According to the results, APP dynamics depends on trophic state, temperature, nutrient, and light availability, as well as grazing pressure. APP abundance in Lake Balaton decreased to a low level (1-2 × 10 5  cells mL -1 ) as a consequence of decreasing nutrient supply (oligotrophication) during the past more than two decades, and followed a characteristic seasonal dynamics with higher abundance values from spring to autumn than in winter. Concomitantly, however, the APP contribution to both phytoplankton biomass and primary production increased (up to 70% and 40-50%, respectively) during oligotrophication. Regarding annual pattern, picocyanobacteria are dominant from spring to autumn, while in winter, picoeukaryotes are the most abundant, most likely due to the different light and temperature optima of these groups. Within picocyanobacteria, single cells and microcolonies were both observed with mid-summer dominance of the latter which correlated well with the density of cladocerans. Community-level chromatic adaptation (i.e., dominance of phycoerythrin- or phycocyanin-rich forms) of planktonic picocyanobacteria was also found as a function of underwater light quality. Sequence analysis studies of APP in Lake Balaton revealed that both picocyanobacteria and picoeukaryotes represent a diverse and dynamic community consisting several freshwater genotypes (picocyanobacteria: Synechococcus, Cyanobium; picoeukaryotes: Choricystis, Stichococcus, Mychonastes, Nannochloris, and Nannochloropsis)., (© 2020. The Author(s).)

Astatic soda pans of the Pannonian Steppe are unique environments with respect to their multiple extreme physical and chemical characteristics (high daily water temperature fluctuation, high turbidity, alkaline pH, salinity, polyhumic organic carbon concentration, hypertrophic state and special ionic composition). However, little is known about the seasonal dynamics of the bacterial communities inhabiting these lakes and the role of environmental factors that have the main impact on their structure. Therefore, two soda pans were sampled monthly between April 2013 and July 2014 to reveal changes in the planktonic community. By late spring in both years, a sudden shift in the community structure was observed, the previous algae-associated bacterial communities had collapsed, resulting the highest ratio of Actinobacteria within the bacterioplankton (89%, with the dominance of acIII-A1 lineage) ever reported in the literature. Before these peaks, an extremely high abundance (> 10,000 individuum l -1 ) of microcrustaceans (Moina brachiata and Arctodiaptomus spinosus) was observed. OTU-based statistical approaches showed that in addition to algal blooms and water-level fluctuations, zooplankton densities had the strongest effect on the composition of bacterial communities. In these extreme environments, this implies a surprisingly strong, community-shaping top-down role of microcrustacean grazers.

Little is known about the detailed community composition of heterotrophic bacterioplankton in macrophyte-dominated littoral systems, where a considerable amount of dissolved organic carbon originates from aquatic macrophytes instead of phytoplankton. The aim of the present study was to reveal the effect of macrophytes on the microbial community and to elucidate their role in a macrophyte-dominated shallow soda lake, which can be characterised by a mosaic of open waters and reed marsh. Therefore, 16S rRNA gene amplicon sequencing, the most probable number method, cultivation of bacterial strains, EcoPlate and cultivation-based substrate utilisation techniques were applied. Differences in the structures of microbial communities were detected between the water and the sediment samples and between vegetated and unvegetated water samples. Planktonic bacterial communities of an inner pond and a reed-covered area showed significant similarities to each other. Woesearchaeia was the dominant archaeal taxon in the water samples, while Bathyarchaeia, 'Marine Benthic Group D' and 'DHVEG-1' were abundant in the sediment samples. The most probable number of heterotrophic bacteria was lower in the open water than in the reed-associated areas. The vast majority (83%) of the isolated bacterial strains from the water samples of the reed-covered area were able to grow on a medium containing reed extract as the sole source of carbon., (© FEMS 2020.)

Gut microbiota can crucially influence behavior and neurodevelopment. Dogs show unique similarities to humans in their physiology and may naturally develop dementia-like cognitive decline. We assessed 29 pet dogs' cognitive performance in a memory test and analyzed the bacterial 16S rRNA gene from fecal samples collected right after the behavioral tests. The major phyla identified in the dog microbiomes were Bacteroidetes, Firmicutes, and Fusobacteria, each represented by >20% of the total bacterial community. Fewer Fusobacteria were found in older dogs and better memory performance was associated with a lower proportion of Actinobacteria. Our preliminary findings support the existence of links between gut microbiota, age, and cognitive performance in pet dogs.

Periglacial and volcanic environments are considered terrestrial analogs of Mars with regard to astrobiological characteristics due to their specific set of extreme features. Ojos del Salado, the highest volcano on Earth (6893 m a.s.l.), is surrounded by several craters, one of which harbors the highest known altitude lake (6480 m a.s.l.), which is influenced by a rare combination of extreme environmental factors, that is, low mean temperature, permafrost, fumarolic activity, acidity, and extreme low organic matter content. To assess the genetic diversity and ecological tolerance of bacteria, samples were taken in February 2016 from the sediments covered with acidic cold (pH 4.88, 3.8°C) and warm (pH 2.08, 40.8°C) water. As a control, a nonvolcanic high-altitude lake (at 5900 m a.s.l.) was also studied by both cultivation-based and next-generation DNA sequencing methods. Isolates from the crater lake showed tolerance toward acidic pH values, unlike isolates from the nonvolcanic lake. Illumina MiSeq sequencing of the 16S rRNA gene exposed simplified, although characteristically different, bacterial communities in the warm and cold water-saturated sediments. In the fumarolic creek sediments, acidophilic iron oxidizers ( Ferrithrix , Gallionella ) and iron reducers ( Acidiphilium ) were abundant, and bacteria involved in the sulfur oxidation ( Hydrogenobaculum, Thiomonas ) and reduction ( Desulfosporosinus ) were also detected. Therefore, we propose an integrated model that addresses the potential role of bacteria in the sulfur and iron geomicrobiological cycles.

A new aerobic betaproteobacterium, strain SA-152 T , was isolated from the water of a crater lake. 16S rRNA gene sequence analysis revealed that strain SA-152 T belonged to the family Oxalobacteraceae (order Burkholderiales ) and was phylogenetically related to Solimicrobium silvestre S20-91 T with 97.09 % and to Herminiimonas arsenicoxydans ULPAs1 T with 96.00 % 16S rRNA gene pairwise sequence similarity. Cells of strain SA-152 T were rod-shaped, non-motile, oxidase-negative and catalase-positive. Its fatty acid profile was dominated by two fatty acids, C 16 : 1 ω 7 c and C 16 : 0 , the major respiratory quinones were Q-8 and Q-7, and the main polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The G+C content of the genomic DNA of strain SA-152 T was 48.3 mol%. The new bacterium can be distinguished from closely related genera Solimicrobium , Herminiimonas , Rugamonas and Undibacterium based on its non-motile and oxidase-negative cells. On the basis of the phenotypic, chemotaxonomic and genomic data, strain SA-152 T is considered to represent a novel species of a new genus, for which the name Sapientia aquatica gen. nov., sp. nov. is proposed. The type strain of Sapientia aquatica is SA-152 T (=DSM 29805 T =NCAIM B.02613 T ).

Actinobacteria in the Tsukamurella genus are aerobic, high-GC, Gram-positive mycolata, considered as opportunistic pathogens and isolated from various environmental sources, including sites contaminated with oil, urban or industrial waste and pesticides. Although studies look into xenobiotic biotransformation by Tsukamurella isolates, the relevant enzymes remain uncharacterized. We investigated the arylamine N-acetyltransferase (NAT) enzyme family, known for its role in the xenobiotic metabolism of prokaryotes and eukaryotes. Xenobiotic sensitivity of Tsukamurella paurometabola type strain DSM 20162 T was assessed, followed by cloning, recombinant expression and functional characterization of its single NAT homolog (TSUPD)NAT1. The bacterium appeared quite robust against chloroanilines, but more sensitive to 4-anisidine and 2-aminophenol. However, metabolic activity was not evident towards those compounds, presumably due to mechanisms protecting cells from xenobiotic entry. Of the pharmaceutical arylhydrazines tested, hydralazine was toxic, but the bacterium was less sensitive to isoniazid, a drug targeting mycolic acid biosynthesis in mycobacteria. Although (TSUPD)NAT1 protein has an atypical Cys-His-Glu (instead of the expected Cys-His-Asp) catalytic triad, it is enzymatically active, suggesting that this deviation is likely due to evolutionary adaptation potentially serving a different function. The protein was indeed found to use malonyl-CoA, instead of the archetypal acetyl-CoA, as its preferred donor substrate. Malonyl-CoA is important for microbial biosynthesis of fatty acids (including mycolic acids) and polyketide chains, and the corresponding enzymatic systems have common evolutionary histories, also linked to xenobiotic metabolism. This study adds to accummulating evidence suggesting broad phylogenetic and functional divergence of microbial NAT enzymes that goes beyond xenobiotic metabolism and merits investigation.

Two new species of the new genus Decimodrilus gen. n. are described in this paper from oak forests of South Korea using a combination of classical morphology and DNA-based molecular taxonomy. A characteristic trait of the new genus is the occurrence of the intestinal diverticula in segments IX-X. The main morphological features of the new genus are: 4-5(6) straight chaetae per bundle, origin of dorsal vessel in clitellar region, anteseptale of nephridia consisting of funnel only, coelomocytes only mucocytes, oesophageal appendages absent, spermathecae united proximally and connected jointly with the oesophagus. Decimodrilus diverticulatus sp. n. has spermathecae with two diverticula-like protrusions and two globular sperm masses. D. globulatus sp. n. has spermathecae with two or three sperm rolls. Molecular taxonomic analysis based on a concatenated phylogenetic tree supports the status of the new genus and that of the two new species.

In April 2014, dual bloom of green algae and purple bacteria occurred in a shallow, alkaline soda pan (Kiskunság National Park, Hungary). The water was only 5 cm deep, in which an upper green layer was clearly separated from a near-sediment purple one. Based on microscopy and DNA-based identification, the upper was inhabited by a dense population of the planktonic green alga, Oocystis submarina Lagerheim, while the deeper layer was formed by purple, bacteriochlorophyll-containing bacteria, predominated by Thiorhodospira and Rhodobaca. Additional bacterial taxa with a presumed capability of anoxygenic phototrophic growth belonged to the genera Loktanella and Porphyrobacter. Comparing the bacterial community of the purple layer with a former blooming event in a nearby soda pan, similar functional but different taxonomic composition was revealed. Members from many dominant bacterial groups were successfully cultivated including potentially new species, which could be the result of the application of newly designed media.

A new aerobic alphaproteobacterium, strain SA-279 T , was isolated from a water sample of a crater lake. The 16S rRNA gene sequence analysis revealed that strain SA-279 T formed a distinct lineage within the family Ancalomicrobiaceae and shared the highest pairwise similarity values with Pinisolibacterravus E9 T (96.4 %) and Ancalomicrobiumadetum NBRC 102456 T (94.2 %). Cells of strain SA-279 T were rod-shaped, motile, oxidase and catalase positive, and capable of forming rosettes. Its predominant fatty acids were C18 : 1ω7c (69.0 %) and C16 : 1ω7c (22.7 %), the major respiratory quinone was Q-10, and the main polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, an unidentified aminophospholipid and an unidentified lipid. The G+C content of the genomic DNA of strain SA-279 T was 69.2 mol%. On the basis of the phenotypic, chemotaxonomic and molecular data, strain SA-279 T is considered to represent a new genus and species within the family Ancalomicrobiaceae, for which the name Siculibacillus lacustris gen. nov., sp. nov. is proposed. The type strain is SA-279 T (=DSM 29840 T =JCM 31761 T ).

A Gram-stain-negative, aerobic, non-motile and coccus-shaped bacterium, designated strain FeSDHB5-19 T , was isolated from a biofilm sample collected from a radioactive thermal spring (Budapest, Hungary), after exposure to 5 kGy gamma radiation. A polyphasic approach was used to study the taxonomic properties of strain FeSDHB5-19 T , which had highest 16S rRNA gene sequence similarity to Deinococcus antarcticus G3-6-20 T (96.5 %). The 16S rRNA gene sequence similarity to type strains of other Deinococcus species were 93.0 % or lower. The DNA G+C content of the draft genome sequence, consisting of 3.9 Mb, was 63.9 mol%. Strain FeSHDB5-19 T was found to grow at temperatures of 10-32 °C (optimum, 28 °C) and pH 5-10 (pH 6.5-7.5) and tolerated up to 1.5 % NaCl (w/v) with optimum growth at 0-0.5 % NaCl. The predominant fatty acids (>10 %) were C16 : 0 and C16 : 1ω7c. The cell-wall peptidoglycan type was A3β l-Orn-Gly1-2. The whole-cell sugars were glucose and low amounts of galactose. Strain FeSDHB5-19 T possessed MK-8 as the predominant respiratory quinone, typical of the genus Deinococcus. The polar lipid profile contained unidentified phosphoglycolipids and unidentified glycolipids. The isolate was found to be highly resistant to gamma (D10<8 kGy) and UV (D10~800 J m -2 ) radiation. According to its genotypic, phenotypic and chemotaxonomic characteristics, strain FeSDHB5-19 T represents a novel species in the genus Deinococcus, for which the name Deinococcusfonticola sp. nov. is proposed. The type strain is FeSDHB5-19 T (=NCAIM B.02639 T =DSM 106917 T ).

This paper presents study on the microbiome of a unique extreme environment - saline and alkaline lime, a by-product of soda ash and table salt production in Janikowo, central Poland. High-throughput 16S rDNA amplicon sequencing was used to reveal the structure of bacterial and archaeal communities in the lime samples, taken from repository ponds differing in salinity (2.3-25.5% NaCl). Surprisingly abundant and diverse bacterial communities were discovered in this extreme environment. The most important geochemical drivers of the observed microbial diversity were salinity, calcium ions, nutrients, and water content. The bacterial and archaeal communities in saline, alkaline lime were similar to those found in natural haloalkaline environments. Although the archaeal contribution to the whole microbial community was lower than 4%, the four archaeal genera Natronomonas, Halorubrum, Halobellus, and Halapricum constituted the core microbiome of saline, alkaline lime - a set of OTUs (> 0.1% of total archaeal relative abundance) present in all samples under study. The high proportion of novel, unclassified archaeal and bacterial sequences (not identified at 97% similarity level) in the 16S rRNA gene libraries indicated that potentially new genera, especially within the class of Thermoplasmata inhabit this unique environment., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The enchytraeid fauna of three areas in Jeju Island (Korea) was studied, and comparative morphological and molecular taxonomic examinations (based on CO1, ITS and H3 sequences) were performed on nine samples collected in 2016. Twenty-two enchytraeid species were recorded and identified. The descriptions of two new species ( Achaetamultisacculata sp. n. and Fridericiafloriformis sp. n. ) are presented in this paper. The main diagnostic features of A.multisacculata sp. n. are: three pairs of pyriform glands per segment, clitellum with two "baguette-like" packages of glands, dorsal blood vessel from VII, secondary pharyngeal glands absent, oesophageal appendages well developed, two pairs of preclitellar nephridia, the reproductive organs (except the spermathecae in V) shifted one segment forward. The main features of F.floriformis sp. n. are that they are large worms, have up to 2-4 chaetae in bundles, strong body wall, thick cuticle, five pairs of preclitellar nephridia, c-type coelomo-mucocytes sometimes with some refractile vesicles, chylus cells in XII-XV, sperm funnels approximately twice as long than wide, spermathecae with long ectal duct without glands, ampullae surrounded distally by about 9-12 sessile diverticula of varying size. Molecular phylogenetic analyses supported the morphological results and confirmed the status of the two new species.

The Carpathian Basin is a lowland plain located mainly in Hungary. Due to the nature of the bedrock, alluvial deposits, and a bowl shape, many lakes and ponds of the area are characterized by high alkalinity. In this study, we characterized temporal changes in eukaryal and bacterial community dynamics with high throughput sequencing and relate the changes to environmental conditions in Lake Velence located in Fejér county, Hungary. The sampled Lake Velence microbial populations (algal and bacterial) were analyzed to identify potential correlations with other community members and environmental parameters at six timepoints over 6 weeks in the Spring of 2012. Correlations between community members suggest a positive relationship between certain algal and bacterial populations (e.g. Chlamydomondaceae with Actinobacteria and Acidobacteria), while other correlations allude to changes in these relationships over time. During the study, high nitrogen availability may have favored non-nitrogen fixing cyanobacteria, such as the toxin-producing Microcystis aeruginosa, and the eutrophic effect may have been exacerbated by high phosphorus availability as well as the high calcium and magnesium content of the Carpathian Basin bedrock, potentially fostering exopolymer production and cell aggregation. Cyanobacterial bloom formation could have a negative environmental impact on other community members and potentially affect overall water quality as well as recreational activities. To our knowledge, this is the first prediction for relationships between photoautotrophic eukaryotes and bacteria from an alkaline, Hungarian lake.

This paper presents the results of the study on the production of protease by Bacillus luteus H11 isolated from an alkaline soda lime. B. luteus H11 was identified as an alkalohalophilic bacterium, and its extracellular serine endoprotease also showed an extreme alkali- and halotolerance. It was remarkably stable in the presence of NaCl up to 5 M. The enzyme was active in a broad range of pH values and temperatures, with an optimum pH of 10.5 and a temperature of 45 °C. It had a molecular mass of about 37 kDa and showed activity against azocasein and a synthetic substrate for the subtilisin-like protease, N-succinyl-l-phenylalanine- p -nitroanilide. The halo-alkaline protease produced by B. luteus H11 seems to be significant from an industrial perspective because of its tolerance towards high salinity and alkalinity as well as its stability against some organic solvents, surfactants and oxidants. These properties make the protease suitable for applications in food, detergent and pharmaceutical industries, and also in environmental bioremediation., Competing Interests: CONFLICT OF INTEREST: The authors declare no conflict of interest.

A novel isolate, strain SA-276 T , was isolated from the water of Lake St. Ana, a crater lake which is located in Romania. Phylogenetic analysis based on the 16S rRNA gene revealed that the new strain is a member of the family Rhizobiaceae, showing a high pairwise similarity value (97.65%) to Rhizobium tubonense CCBAU 85046 T (= DSM 25379 T ), Rhizobium leguminosarum USDA 2370 T (= LMG 14904 T ), Rhizobium anhuiense CCBAU 23252 T and Rhizobium laguerreae FB206 T . Cells of strain SA-276 T were rod-shaped, motile, oxidase negative and weakly catalase positive. The predominant fatty acids were C 18:1 ω7c and cyclo C 19:0 ω8c, the major respiratory quinones were Q-10 and Q-9, and the main polar lipids were phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine. The G + C content of the genomic DNA of strain SA-276 T was 60.8 mol%. The novel isolate can be distinguished from the closest related type strain R. tubonense DSM 25379 T based on its broader substrate specificity and positive trypsin enzyme activity. On the basis of the phenotypic, chemotaxonomic and molecular data, strain SA-276 T is considered to represent a new species, for which the name Rhizobium aquaticum sp. nov. is proposed. The type strain is SA-276 T (= DSM 29780 T  = JCM 31760 T ).

One enchytraeid species, proved to be new to science, is described in this paper as Fridericia ventrochaetosa sp. nov. The new species is distinguished from similar species, especially from F. galba (Hoffmeister, 1843), which has almost the same type of spermatheca, on the basis of morphological characters and molecular data (nuclear ribosomal ITS region, mitochondrial cytochrome c oxidase subunit I and nuclear histone 3 gene sequences). Apart form the new species, GenBank reference sequences are provided for the first time for F. hegemon and F. regularis. The results show that, although the shape of the spermatheca is a very important marker in the case of Fridericia species, other characters can be equally important for their taxonomic identification.

The enchytraeid fauna of Mt. Hallasan (Jeju Island, Korea) was studied in 2016, and 21 enchytraeid species were recorded and identified in total. A combination of morphological and molecular analyses (based on CO1, ITS and H3 sequences) was applied. Here we give descriptions of eight new species of Enchytraeidae (Clitellata): Achaeta koreana sp. n., Achaeta macroampullacea sp. n., Bryodrilus hallasanensis sp. n., Chamaedrilus baekrokdamensis sp. n., Enchytronia seongpanakiensis sp. n., Mesenchytraeus jungsaihoi sp. n., Xetadrilus jejuensis sp. n. and Xetadrilus aphanoides sp. n. Additionally, two species were found to be new for the Korean fauna in Mt. Hallasan: Fridericia cf. paroniana Issel, 1904 and F. perrieri (Vejdovský, 1878); three potentially new Fridericia species require further studies. Furthermore, two terrestrial polychaetes, Hrabeiella periglandulata Pižl Chalupský, 1984 and Parergodrilus heideri Resisinger, 1925, were recorded. For 12 enchytraeid species, DNA sequences are presented for the first time: these include, apart from the new species, further taxa such as species of Xetadrilus, a genus of which no sequences were previously available.