Tamás Felföldi

Polyphasic bacterial community analysis of an aerobic activated sludge removing phenols and thiocyanate from coke plant effluent

Biological purification processes are effective tools in the treatment of hazardous wastes such as toxic compounds produced in coal coking. In this study, the microbial community of a lab-scale activated sludge system treating coking effluent was assessed by cultivation-based (strain isolation and identification, biodegradation tests) and culture-independent techniques (sequence-aided T-RFLP, taxon-specific PCR). The results of the applied polyphasic approach showed a simple microbial community dominated by easily culturable heterotrophic bacteria. Comamonas badia was identified as the key microbe of the system, since it was the predominant member of the bacterial community, and its phenol degradation capacity was also proved. Metabolism of phenol, even at elevated concentrations (up to 1500mg/L), was also presented for many other dominant (Pseudomonas, Rhodanobacter, Oligella) and minor (Alcaligenes, Castellaniella, Microbacterium) groups, while some activated sludge bacteria (Sphingomonas, Rhodopseudomonas) did not tolerate it even in lower concentrations (250mg/L). In some cases, closely related strains showed different tolerance and degradation properties. Members of the genus Thiobacillus were detected in the activated sludge, and were supposedly responsible for the intensive thiocyanate biodegradation observed in the system. Additionally, some identified bacteria (e.g. C. badia and the Ottowia-related strains) might also have had a significant impact on the structure of the activated sludge due to their floc-forming abilities.

Detection of potentially pathogenic bacteria in the drinking water distribution system of a hospital in Hungary

The drinking water distribution system of a hospital was investigated using standard cultivation techniques, taxon-specific PCRs targeting pathogenic bacteria, denaturing gradient gel electrophoresis, cloning and sequencing. The results obtained verify the higher sensitivity of PCR compared to cultivation for detecting Legionella and Pseudomonas aeruginosa. Moreover, several other opportunistic pathogenic bacteria, such as Escherichia albertii, Acinetobacter lwoffi and Corynebacterium tuberculostrearicum, were detected, emphasizing that drinking water systems, especially those with stagnant water sections, could be the source of nosocomial infections.

Ferrate treatment for inactivation of bacterial community in municipal secondary effluent

This paper demonstrates the effect of ferrate [Fe(VI)-compound], an environmental friendly multi-purpose reagent, in municipal secondary effluent treatment. The purpose was to study the inactivation capability of ferrate and for the first time to compare the effect and efficiency of Fe(VI) with the widely used disinfectant, chlorine gas on the indigenous bacterial community in the case of secondary effluents. The most probable number technique (MPN) was applied for the determination of cultivable heterotrophic bacterial abundance and terminal restriction fragment length polymorphism (T-RFLP) analysis for comparing bacterial communities. The study demonstrated that (i) ferrate and chlorine had different effect on the total bacterial community of secondary effluents, (ii) low ferrate dose [5 mg L(-1) Fe(VI)] was sufficient for >99.9% reduction of indigenous bacteria, and (iii) a similar dosage was also effective in the inactivation of chlorine-resistant bacteria.

Development of a 16S rRNA gene-based prototype microarray for the detection of selected actinomycetes genera

Actinomycetes are known for their secondary metabolites, which have been successfully used as drugs in human and veterinary medicines. However, information on the distribution of this group of Gram-positive bacteria in diverse ecosystems and a comprehension of their activities in ecosystem processes are still scarce. We have developed a 16S rRNA-based taxonomic microarray that targets key actinomycetes at the genus level. In total, 113 actinomycete 16S rRNA probes, corresponding to 55 of the 202 described genera, were designed. The microarray accuracy was evaluated by comparing signal intensities with probe/target-weighted mismatch values and the Gibbs energy of the probe/target duplex formation by hybridizing 17 non-actinomycete and 29 actinomycete strains/clones with the probe set. The validation proved that the probe set was specific, with only 1.3% of false results. The incomplete coverage of actinomycetes by a genus-specific probe was caused by the limited number of 16S rRNA gene sequences in databases or insufficient 16S rRNA gene polymorphism. The microarray enabled discrimination between actinomycete communities from three forest soil samples collected at one site. Cloning and sequencing of 16S rRNA genes from one of the soil samples confirmed the microarray results. We propose that this newly constructed microarray will be a valuable tool for genus-level comparisons of actinomycete communities in various ecological conditions.

Chloroparva pannonica gen. et sp. nov. (Trebouxiophyceae, Chlorophyta) - a new picoplanktonic green alga from a turbid, shallow soda pan

Somogyi B., Felföldi T., Solymosi K., Makk J., Homonnay Z.G., Horváth G., Turcsi E., Böddi B., Márialigeti K. and Vörös L. 2011. Chloroparva pannonica gen. et sp. nov. (Trebouxiophyceae, Chlorophyta) – a new picoplanktonic green alga from a turbid, shallow soda pan. Phycologia 50: 1–10. DOI: 10.2216/10-08.1 We describe Chloroparva pannonica Somogyi, Felföldi & Vörös gen. et sp. nov., a new trebouxiophycean picoplanktonic alga isolated from a turbid, shallow soda pan in Hungary. The cells are spherical to oval, less than 2 µm in diameter, with simple ultrastructure typical to small green algae. Cells divide by autosporulation, forming two daughter cells per autosporangium. Cell wall structure consists of an outer trilaminar layer, an inner microfibrillar layer and an electron-transparent layer covering the plasma membrane. The trilaminar layer of the mother cell wall often persists around the autospores. Typical chlorophyte pigments have been found, including chlorophyll a and b and lutein as the dominant carotenoid. The main fatty acid was oleic acid. The phylogenetic position of the new chlorophyte confirms the proposal of a new genus within the Trebouxiophyceae. Based on its 18S rRNA gene sequence, this isolate is distantly related to Nannochloris eucaryotum UTEX 2502, Chlorella minutissima C-1.1.9 and C. minutissima SAG 1.80 (≤ 97.6% 18S rRNA gene pairwise similarities).

Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

Blooms of toxic cyanobacteria are well-known phenomena in many regions of the world. Microcystin (MC), the most frequent cyanobacterial toxin, is produced by entirely different cyanobacteria, including unicellular, multicellular filamentous, heterocytic, and non-heterocytic bloom-forming species. Planktothrix is one of the most important MC-producing genera in temperate lakes. The reddish color of cyanobacterial blooms viewed in a gravel pit pond with the appearance of a dense 3 cm thick layer (biovolume: 28.4 mm3 L−1) was an unexpected observation in the shallow lake-dominated alluvial region of the Carpathian Basin. [d-Asp3, Mdha7]MC–RR was identified from the blooms sample by MALDI-TOF and NMR. Concentrations of [d-Asp3, Mdha7]MC–RR were measured by capillary electrophoresis to compare the microcystin content of the field samples and the isolated, laboratory-maintained P. rubescens strain. In analyzing the MC gene cluster of the isolated P. rubescens strain, a deletion in the spacer region between mcyE and mcyG and an insertion were located in the spacer region between mcyT and mcyD. The insertion elements were sequenced and partly identified. Although some invasive tropical cyanobacterial species have been given a great deal of attention in many recent studies, our results draw attention to the spread of the alpine organism P. rubescens as a MC-producing, bloom-forming species.

Ottowia pentelensis sp. nov., a floc-forming betaproteobacterium isolated from an activated sludge system treating coke plant effluent

A Gram-negative-staining, short-rod-shaped, floc-forming bacterium, designated strain RB3-7(T), was isolated from a laboratory-scale activated sludge system treating coke plant effluent. Comparative analysis of the 16S rRNA gene sequence demonstrated that the novel isolate was distantly related (≤ 95.8 % similarity) to Ottowia thiooxydans K11(T) within the family Comamonadaceae. Strain RB3-7(T) was catalase- and oxidase-positive and non-motile. The predominant fatty acids were C₁₆:₀, cyclo C₁₇:₀, C₁₈:₁ω7c and C₁₆:₁ω7c, and the major respiratory quinone was Q-8. The G+C content of the genomic DNA of strain RB3-7(T) was 68.5 mol%. On the basis of phenotypic, chemotaxonomic and molecular data, strain RB3-7(T) is considered to represent a novel species of the genus Ottowia, for which the name Ottowia pentelensis sp. nov. is proposed. The type strain is RB3-7(T) ( = DSM 21699(T) = NCAIM B 02336(T)).

Agriotes proximus and A. lineatus (Coleoptera: Elateridae): a comparative study on the pheromone composition and cytochrome c oxidase subunit I gene sequence

The presence of geranyl octanoate, previously found in pheromone gland extracts of Agriotes lineatus females, was also demonstrated in gland extracts of A. proximus females. Similar to A. lineatus, geranyl butanoate was present only in trace amounts in A. proximus female gland extracts. In air entrainment samples of female A. lineatus and A. proximus beetles, the relative ratio of geranyl butanoate and geranyl octanoate was higher than that in gland extracts. In addition, comparison of a segment of the mitochondrial cytochrome c oxidase subunit I gene of feral specimens of A. lineatus and A. proximus showed >99% similarity. Both pheromone profile and nucleotide sequence analysis delineate close relationship between the investigated taxa and postulate taxonomic revision. Further studies on sympatric populations of A. lineatus and A. proximus are underway to investigate and better understand possible processes of species diversification.

One step closer to eliminating the nomenclatural problems of minute coccoid green algae: Pseudochloris wilhelmii, gen. et sp. nov. (Trebouxiophyceae, Chlorophyta)

‘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.

Morphometric and molecular studies on the populations of the damselflies Chalcolestes viridis and C. parvidens (Odonata, Lestidae)

Morphometric and genetic differences were analysed for two closely related damselflies, Chalcolestes viridis and C. parvidens. A total of 305 male individuals were collected from six European countries (Austria, Croatia, Germany, Greece, Hungary and Portugal). Measurements from a total of 28 populations of C. viridis and C. parvidens and several intermediate forms were collected to determine if they can be definitely distinguished using simple morphometric characters. DNA sequences from two independent loci (nuclear ribosomal ITS region and mitochondrial cytochrome oxidase I gene) were analysed to test whether these taxa represent separate monophyletic groups as well as to compare the genetic distance with those found between well-accepted European Lestes species. Discriminant analysis revealed that C. viridis and C. parvidens are differentiated in morphometric space. Individuals with intermediate anal appendage traits overlapped with both C. viridis and C. parvidens which raised the possibility that they are merely subspecies of a single species. However, genetic analysis of both investigated DNA regions showed that the two Chalcolestes taxa did not share haplotypes, indicating their status as true species. Furthermore, they formed a monophyletic group separated from the investigated Lestes species, supporting the recognition of the genus Chalcolestes. The two Chalcolestes species are very closely related compared with European Lestes species, suggesting that their divergence occurred relatively recently.