[Show abstract][Hide abstract] ABSTRACT: Winter conditions in aquatic habitats of the temperate zone markedly differ from those
present in warmer seasons, nevertheless, relatively scarce information is available on
planktonic microbial composition, as sites are not easily accessible and it was supposed
traditionally that microbial activity is low during this cold period. Since microorganisms
could have great impact on the ecosystem even during winter, we explored various sites in
the Eastern Carpathians regarding the abundance and taxonomic composition of planktonic
microorganisms. Although many of the studied environments were extreme habitats,
planktonic microbial communities were abundant and mostly diverse with the presence of
previously unidentified taxa
[Show abstract][Hide abstract] ABSTRACT: Oyster mushroom (Pleurotus ostreatus) lignocellulolytic enzyme activity pattern and variation was investigated in a large-scale facility from spawning until the end of the second flush. In the first cultivation cycle laccase production reached its peak during vegetative growth stage, while manganese-peroxidase showed the highest activity during fruiting body induction. Cellulose and hemicellulose degrading enzymes had maximal activity at the beginning of flush and harvest stage. The enzyme activities showed similar tendencies among five different mushroom substrate blocks representing a production house. The spatial variability analysis of enzyme activities pointed out the within substrate block heterogeneity as the main source if variation. This result was confirmed by Combined Cluster and Discriminant Analysis (CCDA) method showing minimal among block heterogeneity considering the whole investigation period; furthermore in the first cultivation cycle all blocks were grouped into one cluster.
[Show abstract][Hide abstract] ABSTRACT: Many halophytes and halophilic microorganisms are capable to adapt to the extremities of saline habitats. This study reveals the taxonomic diversity and ecological tolerance of bacteria isolated from the rhizosphere of three different halophytes (Bolboschoenus maritimus, Puccinellia limosa and Aster tripolium) living in the vicinity of Kiskunság soda ponds. Following a sampling in September 2013, altogether 76 bacterial strains were isolated using two different media. The strains were identified on the basis of 16S rRNA gene sequencing following ARDRA grouping. Salt and pH tolerance of the strains were examined by measuring their growth in broths containing 0-15% NaCl (w/V) and characterized with pH 7-12 values. Among the strains genera of Anaerobacillus, Bacillus and Exiguobacterium (Firmicutes), Agromyces, Isoptericola, Microbacterium, Micrococcus, Nocardiopsis, Nesterenkonia and Streptomyces (Actinobacteria), Halomonas and Idiomarina (Proteobacteria) and Anditalea (Bacteroidetes) were identified. The Bolboschoenus and Puccinellia samples characterized with the highest pH and electric conductivity values were dominated by Bacillus, Halomonas and Nesterenkonia, respectively. The salt tolerance of the bacterial strains was strongly dependent on the sampling location and plant species. In contrast, growth of bacterial strains in broths with alkaline pH values was more balanced. The strains from the Puccinellia sample showed the widest salt and pH tolerance.
Full-text · Article · Jun 2015 · Acta Microbiologica et Immunologica Hungarica
[Show abstract][Hide abstract] ABSTRACT: In this study, scanning electron microscopy (SEM) and 16S rRNA gene-based phylogenetic approach were applied to reveal the morphological structure and genetic diversity of thermophilic prokaryotic communities of a thermal karst well located in Budapest (Hungary). Bacterial and archaeal diversity of the well water (73.7 °C) and the biofilm developed on the inner surface of an outflow pipeline of the well were studied by molecular cloning method. According to the SEM images calcium carbonate minerals serve as a surface for colonization of bacterial aggregates. The vast majority of the bacterial and archaeal clones showed the highest sequence similarities to chemolithoautotrophic species. The bacterial clone libraries were dominated by sulfur oxidizer Thiobacillus (Betaproteobacteria) in the water and Sulfurihydrogenibium (Aquificae) in the biofilm. A relatively high proportion of molecular clones represented genera Thermus and Bellilinea in the biofilm library. The most abundant phylotypes both in water and biofilm archaeal clone libraries were closely related to thermophilic ammonia oxidizer Nitrosocaldus and Nitrososphaera but phylotypes belonging to methanogens were also detected. The results show that in addition to the bacterial sulfur and hydrogen oxidation, mainly archaeal ammonia oxidation may play a decisive role in the studied thermal karst system.
[Show abstract][Hide abstract] ABSTRACT: A strain designated PYM3-14T was isolated from the drinking water network of Budapest (Hungary) and was studied by polyphasic taxonomic methods. The straight rod shaped cells stained Gram-negative, were aerobic and non-motile. Phylogenetic analysis of the 16S rRNA gene sequence of strain PYM3-14T revealed a clear affiliation with members of the family 'Xanthomonadaceae' within Gammaproteobacteria. The 16S rRNA gene sequence of strain PYM3-14T showed the closest sequence similarities to Arenimonas daechungensis CH15-1T (96.2 %), Arenimonas oryziterrae YC6267T (95.2 %) and Lysobacter brunescens UASM DT (94.4 %). The DNA G+C content of strain PYM3-14T was much lower than any members of the genus Arenimonas measured by two different methods (52.0 mol% and 55.9 mol%, respectively). The predominant fatty acids (> 8%) were iso-C16 : 0 and iso-C15 : 0, iso-C14 : 0, iso-C17 : 1 ω9c and C16 : 1 ω7c alcohol. Strain PYM3-14T contained Q-8 as the major ubiquinone and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylmonomethylethanolamine as the major polar lipids. According to phenotypic and genotypic data strain PYM3-14T represents a novel species for which the name Arenimonas subflava sp. nov. is proposed. The type strain is PYM3-14T (=NCAIM B 02508T=DSM 25526T). On the basis of new data obtained in this study, an emended description of the genus Arenimonas is also proposed.
No preview · Article · Mar 2015 · International Journal of Systematic and Evolutionary Microbiology
[Show abstract][Hide abstract] ABSTRACT: Effect of carrier texture and type on biofilm development and maturation were studied on an eight-reactors-containing pilot-scale cascade system which treated municipal wastewater under aerobic conditions and various system operational characteristics. Dissimilarities in the biofilm structures grown on four types of polymer fiber-based carriers placed in the reactors having different role during wastewater purification and compositional changes of bacterial communities during biofilm maturation were clearly observable. In the first 2-3 weeks, taxonomic diversity of biofilm bacterial communities increased and reached their maximum values. Carrier type and texture had comparable effect on the weight, activity and composition of biofilms as the wastewater matrix. Biofilm community grown on the carrier having the best colonization properties were dominated by Proteobacteria, Synergistetes, Bacteroidetes and Firmicutes. In the nascent 7-days-old biofilm, aerobic chemoorganotrophic genera, while in the mature 45-days-old biofilm anaerobes, such as sulfate-reducer and fermentative genera were the major members of the bacterial communities.
No preview · Article · Mar 2015 · The Chemical Engineering Journal
[Show abstract][Hide abstract] ABSTRACT: Geothermal wells characterized by thermal waters warmer than 30°C can be found in more than 65% of the area of Hungary. The examined thermal wells located nearby Szarvas are used for heating industrial and agricultural facilities because of their relatively high hydrocarbon content. The aim of this study was to reveal the prokaryotic community structure of the water of SZR18, K87 and SZR21 geothermal wells using molecular cloning methods and Denaturing Gradient Gel Electrophoresis (DGGE). Water samples from the outflow pipes were collected in 2012 and 2013. The phylogenetic distribution of archaeal molecular clones was very similar in each sample, the most abundant groups belonged to the genera Methanosaeta, Methanothermobacter and Thermofilum. In contrast, the distribution of bacterial molecular clones was very diverse. Many of them showed the closest sequence similarities to uncultured clone sequences from similar thermal environments. From the water of the SZR18 well, phylotypes closely related to genera Fictibacillus and Alicyclobacillus (Firmicutes) were only revealed, while the bacterial diversity of the K87 well water was much higher. Here, the members of the phyla Thermodesulfobacteria, Proteobacteria, Nitrospira, Chlorobi, OP1 and OPB7 were also detected besides Firmicutes.
[Show abstract][Hide abstract] ABSTRACT: A preliminary study was conducted to compare the community level physiological profile (CLPP) and genetic diversity of rhizosphere microbial communities of four plant species growing nearby Kiskunság soda ponds, namely Böddi-szék, Kelemen-szék and Zab-szék. CLPP was assessed by MicroResp method using 15 different substrates while Denaturing Gradient Gel Electrophoresis (DGGE) was used to analyse genetic diversity of bacterial communities. The soil physical and chemical properties were quite different at the three sampling sites. Multivariate statistics (PCA and UPGMA) revealed that Zab-szék samples could be separated according to their genetic profile from the two others which might be attributed to the geographical location and perhaps the differences in soil physical properties. Böddi-szék samples could be separated from the two others considering the metabolic activity which could be explained by their high salt and low humus contents. The number of bands in DGGE gels was related to the metabolic activity, and positively correlated with soil humus content, but negatively with soil salt content. The main finding was that geographical location, soil physical and chemical properties and the type of vegetation were all important factors influencing the metabolic activity and genetic diversity of rhizosphere microbial communities.
[Show abstract][Hide abstract] ABSTRACT: The Buda Thermal Karst System is an active hypogenic karst area that offers possibility for the analysis of biogenic cave formation. The aim of the present study was to gain information about morphological structure and genetic diversity of bacterial communities inhabiting the Diana-Hygieia Thermal Spring (DHTS). Using scanning electron microscopy, metal accumulating and unusual reticulated filaments were detected in large numbers in the DHTS biofilm samples. The phyla Actinobacteria, Firmicutes and Proteobacteria were represented by both bacterial strains and molecular clones but phyla Acidobacteria, Chlorobi, Chlorofexi, Gemmatimonadetes, Nitrospirae and Thermotogae only by molecular clones which showed the highest similarity to uncultured clone sequences originating from different environmental sources. The biofilm bacterial community proved to be somewhat more diverse than that of the water sample and the distribution of the dominant bacterial clones was different between biofilm and water samples. The majority of biofilm clones was affiliated with Deltaproteobacteria and Nitrospirae while the largest group of water clones was related to Betaproteobacteria. Considering the metabolic properties of known species related to the strains and molecular clones from DHTS, it can be assumed that these bacterial communities may participate in the local sulphur and iron cycles, and contribute to biogenic cave formation.
No preview · Article · Sep 2014 · Acta Microbiologica et Immunologica Hungarica
[Show abstract][Hide abstract] ABSTRACT: Bacterial communities of a bank-filtered drinking water system were investigated by aerobic cultivation and clone library analysis. Moreover, bacterial communities were compared using sequence-aided terminal restriction fragment length polymorphism (T-RFLP) fingerprinting at ten characteristic points located at both the collecting and the distributing part of the water supply system. Chemical characteristics of the samples were similar, except for the presence of chlorine residuals in the distribution system and increased total iron concentration in two of the samples. Assimilable organic carbon (AOC) concentration increased within the collection system, it was reduced by chlorination and it increased again in the distribution system. Neither fecal indicators nor pathogens were detected by standard cultivation techniques. Chlorination reduced bacterial diversity and heterotrophic plate counts. Community structures were found to be significantly different before and after chlorination: the diverse communities in wells and the collection system were dominated by chemolithotrophic (e.g., Gallionella and Nitrospira) and oligocarbophilic–heterotrophic bacteria (e.g., Sphingomonas, Sphingopyxis, and Bradyrhizobium). After chlorination in the distribution system, the most characteristic bacterium was related to the facultative methylotrophic Methylocella spp. Communities changed within the distribution system too, Mycobacterium spp. or Sphingopyxis spp. became predominant in certain samples.
No preview · Article · Jul 2014 · Journal of Basic Microbiology
[Show abstract][Hide abstract] ABSTRACT: A new bacterium, PB3-7BT, was isolated on phenol-supplemented inorganic growth medium from a laboratory-scale wastewater purification system that treated coke plant effluent. The 16S rRNA gene sequence analysis revealed that strain PB3-7BT belonged to the family Alcaligenaceae and possessed the highest pairwise similarity values to Parapusillimonas granuli LMG 24012T (97.5%), Candidimonas bauzanensis DSM 22805T (97.3%) and Pusillimonas noertemannii DSM 10065T (97.2%). Strain PB3-7BT was rod-shaped, motile, oxidase and catalase positive. The predominant fatty acids were C16:0 (38.8%), cycloC17:0 (20.7%), cycloC19:0ω8c (16.9%), and C14:0 3-OH (10.3%), and the major respiratory quinone was Q-8. The G + C content of the genomic DNA of strain PB3-7BT was 59.7 mol%. The new bacterium can be distinguished from the closely related type strains based on its positive urease activity and capability for the assimilation of glycerol and amygdalin. On the basis of the phenotypic, chemotaxonomic and molecular data, strain PB3-7BT is considered to represent a new genus and species, for which the name Eoetvoesia caeni gen. nov., sp. nov. is proposed. The type strain is PB3-7BT (=DSM 25520T=NCAIM B 02512T).
Preview · Article · Feb 2014 · International Journal of Systematic and Evolutionary Microbiology
[Show abstract][Hide abstract] ABSTRACT: The effect of vertical physico-chemical stratification on the planktonic microbial community composition of the deep, hypersaline and heliothermal Lake Ursu (Sovata, Romania) was examined in this study. On site and laboratory measurements were performed to determine the physical and chemical variables of the lake water, and culture-based and cultivation-independent techniques were applied to identify the members of microbial communities. The surface of the lake was characterized by a low salinity water layer while the deepest region was extremely saline (up to 300 g/L salinity). Many parameters (e.g. photosynthetically active radiation, dissolved oxygen concentration, pH, redox potential) changed dramatically from 2 to 4 m below the water surface in conjunction with the increasing salinity values. The water temperature reached a maximum at this depth. At around 3 m depth, there was a water layer with high (bacterio) chlorophyll content dominated by Prosthecochloris vibrioformis, a phototrophic green sulfur bacterium. Characteristic microbial communities with various prokaryotic taxa were identified along the different environmental parameters present in the different water layers. Some of these bacteria were known to be heterotrophic and therefore may be involved in the decomposition of lake organic material (e.g. Halomonas, Idiomarina and Pseudoalteromonas) while others in the transformation of sulfur compounds (e.g. Prosthecochloris). Eukaryotic microorganisms identified by molecular methods in the lake water belonged to genera of green algae (Mantionella and Picochlorum), and were restricted mainly to the upper layers.
[Show abstract][Hide abstract] ABSTRACT: The results of 16S rRNA, catA and gyrB gene sequence comparisons and reasserted DNA-DNA hybridization clearly indicated that Rhodococcus jialingiae Wang et al. 2010 (Wang, Z., Xu, J., Li, Y., Wang, K., Wang, Y., Hong, Q., Li, W.J. & Li, S.P. Int. J. Syst. Evol. Microbiol. 60:378-381, 2010) and Rhodococcus qingshengii Xu et al. 2007 (Xu, J.L., He, J., Wang, Z.C., Wang, K., Li, W.J., Tang, S.K. & Li, S.P. Int. J. Syst. Evol. Microbiol. 57:2754-2757, 2007) represent a single species. On the basis of priority R. jialingiae must be considered a later synonym of R. qingshengii.
No preview · Article · Jan 2014 · International Journal of Systematic and Evolutionary Microbiology
[Show abstract][Hide abstract] ABSTRACT: Winter phytoplankton communities in the shallow alkaline pans of Hungary are frequently dominated by picoeukaryotes, sometimes in particularly high abundance. In winter 2012, the ice-covered alkaline Zab-szék pan was found to be extraordinarily rich in picoeukaryotic green algae (42–82 × 106 cells ml−1) despite the simultaneous presence of multiple stressors (low temperature and light intensity with high pH and salinity). The maximum photosynthetic rate of the picoeukaryote community was 1.4 μg C μg chlorophyll a
−1 h−1 at 125 μmol m−2 s−1. The assimilation rates compared with the available light intensity measured on the field show that the community was considerably light-limited. Estimated areal primary production was 180 mg C m−2 d−1. On the basis of the 18S rRNA gene analysis (cloning and DGGE), the community was phylogenetically heterogeneous with several previously undescribed chlorophyte lineages, which indicates the ability of picoeukaryotic communities to maintain high genetic diversity under extreme conditions.
[Show abstract][Hide abstract] ABSTRACT: Strains of a novel Alphaproteobacterium were isolated from the ultrapure water of a Hungarian power plant on a newly developed medium. Phylogenetic analysis of the new strains showed that these bacteria belong to a distinct lineage far from any known taxa. Based on the 16S rRNA gene sequences, strains PI_31, PI_25 and PI_21T exhibit the highest sequence similarity values to Bosea minatitlanensis AMX51T (93.43%) and to Bosea thiooxidans DSM 9653T(93.36%), similarity to all other taxa is less than 93.23%. Fatty acid profiles, MALDI-TOF mass spectra of cell extracts as well as physiological and biochemical characteristics indicate that our strains represent a novel genus and species within the Alphaproteobacteria. The major isoprenoid quinone of the strains is Q-10, the major cellular fatty acids are C18:1w7c and 11Me18:1w7c, the polar lipid profile of strains contains phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and several unknown phospholipids and other lipids. The characteristic diamino acid in their cell wall is meso-diaminopimelic acid. The G+C content of DNA of the type strain is 68.9 mol%. PI_21T (=DSM 25521T =NCAIM B 02510T) is proposed as type strain of the new genus and species, Phreatobacter oligotrophus.
Preview · Article · Nov 2013 · International Journal of Systematic and Evolutionary Microbiology
[Show abstract][Hide abstract] ABSTRACT: A Gram-negative, rod-shaped bacterium, designated strain ERB1-3T, was isolated from a laboratory-scale activated sludge system treating coke plant effluent using thiocyanate-supplemented growth medium. Strain ERB1-3T was oxidase positive, weakly catalase positive and motile. The predominant fatty acids were C18:1ω7c and C17:1ω6c, and the major respiratory quinone was Q-10. Polar lipids were dominated by sphingoglycolipid and phosphatidylglycerol. The G + C content of the genomic DNA of strain ERB1-3T was 66.4 mol%. Based on the 16S rRNA gene, strain ERB1-3T exhibited the highest sequence similarity values to Sphingomonas sanxanigenens DSM 19645T (96.1%), Sphingobium scionense DSM 19371T (95.1%) and Stakelama pacifica LMG 24686T (94.8%) within the family Sphingomonadaceae (Alphaproteobacteria). The new isolate had some unique chemotaxonomic features that differentiated it from these closely related strains, contained the fatty acid cycloC19:0ω8c and possessed diphosphatidylglycerol only in trace amounts. On the basis of the phenotypic, chemotaxonomic and molecular data, strain ERB1-3T is considered to represent a novel genus and species, for which the name Hephaestia caeni gen. nov., sp. nov. is proposed. The type strain is ERB1-3T (=DSM 25527T=NCAIM B 02511T).
Preview · Article · Nov 2013 · International Journal of Systematic and Evolutionary Microbiology
[Show abstract][Hide abstract] ABSTRACT: ‘Chlorella’ and ‘Nannochloris’ were traditional genera of minute coccoid green algae with numerous species described in the past century, including isolates used as experimental test organisms. In the last few years, the introduction of DNA-based phylogenetic analyses resulted in a large number of taxonomic revisions. We investigated and reclassified a taxonomically problematic group within the Trebouxiophyceae (comprising ‘Nannochloris eucaryotum’ UTEX 2502, ‘N. eucaryotum’ SAG 55.87 and ‘Chlorella minutissima’ SAG 1.80), distantly related to the recently described Chloroparva isolates (97.5–97.9 % 18S rRNA gene pairwise similarity). Cryopreserved material of SAG 55.87 was selected as holotype for a novel species – Pseudochloris wilhelmii Somogyi, Felföldi & Vörös – whose phylogenetic position confirmed the proposal of a new genus. Pseudochloris wilhelmii had spherical to oval cells with an average diameter of 2.6 × 2.8 µm and a simple ultrastructure characteristic of small green algae. Vegetative cells sometimes contained several lipid droplets occupying a large portion of the cells. The cell wall consisted of an outer trilaminar layer and an inner microfibrillar sheet. Cells divided by autosporulation, forming two or four daughter cells per autosporangium. The pigment composition was typical of green algae, with chlorophylls a and b, and lutein as the dominant carotenoid.
No preview · Article · Nov 2013 · European Journal of Phycology
[Show abstract][Hide abstract] ABSTRACT: In Hungary, the replacement of geothermal waters previously utilized for industrial purposes is still not resolved. As a workaround, they are usually released to natural surface waters after being stored in reservoirs. Our investigation focused on the Barex Reservoir System near Szarvas which consists of four separate, but interconnected artificial water bodies. According to the water chemical analysis, the utilized thermal water was anaerobic, alkaline, rich in phenol derivatives and was of high salinity. Since little is known about the microbiological properties of these types of environments, the aim of this study was to gain insight to the structure and composition of microbial communities and the influence of changing parameters. The first step of this long-term investigation was to reveal the phylogenetic diversity of microbial communities inhabiting the first lake water, sediment and biofilm developed on the reed surface. The spatial and temporal changes were tracked by DGGE, using primers 27fGC and 519r. Exploration of the phylogenetic diversity of bacteria and archaea was carried out by the construction of three clone libraries respectively, and sequencing 16S rRNA coding regions of DNA. Archaeal diversity was examined by the cloning of ribosomal sequences from the community DNA using primers A109f and A958r. Analyses have shown that bacterial communities of the sediment formed separate groups which showed little similarity to the communities of the lake water during the whole year. Both clone library analyses and DGGE patterns have shown that the influent water differed from every other sample. In the case of water samples, representatives of the Phylum Cyanobacteria were present in large proportions. Arthrospira platensis proved to be a constant member of the lake water community. In both biofilm and sediment samples members of the Genus Hydrogenophaga (Proteobacteria), the Ordines Rhodocyclales and Rhodobacterales and purple non-sulfur bacteria were found to be dominant. Archaeal communities were less diverse than bacterial ones based on the processing of three clone libraries and the similarity was more pronounced between the sample types. The archaeal diversity of the sediment was the most diverse among the sample types. The most common archaeal genera were Metanosaeta and Metanocalculus. The majority of bacteria identified from the Barex Reservoir-System was haloalkalophilic, and might be capable of utilizing a wide range of carbon compounds.