Zsuzsa Kéki

Wohlfahrtiimonas chitiniclastica gen. nov., sp. nov., a new gammaproteobacterium isolated from Wohlfahrtia magnifica (Diptera: Sarcophagidae)

New Gammaproteobacteria were isolated from 3rd stage fly larvae of the parasitic fly Wohlfahrtia magnifica. Phylogenetic analysis of the new isolates showed that these bacteria belong to a distinct lineage close to Ignatzschineria larvae, which was originally isolated from the same species of fly. The low similarity values in 16S rRNA gene sequences (93.8-94.8 %), and differences in fatty acid profiles, RiboPrint patterns, MALDI-TOF mass spectra of cell extracts, and physiological and biochemical characteristics differentiate the isolates from the type strain of Ignatzschineria larvae (DSM 13226T), and indicate that our isolates represent a new genus within the Gammaproteobacteria. The major isoprenoid quinone of the strains is Q8, the major fatty acids are C18 : 1 and C14 : 0, and the predominant polar lipids are phosphatidylglycerol, phosphatidylethanolamine and phosphatidylserine. The G+C content of the DNA of the type strain is 44.3 mol%. The name Wohlfahrtiimonas chitiniclastica gen. nov., sp. nov., is proposed for this novel genus and species. The type strain is S5T (=DSM 18708T=CCM 7401T).

Bacillus aurantiacus sp. nov., an alkaliphilic and moderately halophilic bacterium isolated from Hungarian soda lakes

Three alkaliphilic and moderately halophilic strains designated K1-5T, K1-10 and B1-1, characterized by optimal growth at pH 9.0-10.0 and at 3-7 % (w/v) NaCl, were isolated from extremely shallow, alkaline soda lakes located in Hungary. Cells of the strains are Gram-positive, straight rods and form a central to subterminal, ellipsoidal endospore. The isolates are strictly aerobic, catalase-positive, oxidase-negative and contain a peptidoglycan of type A1 gamma based on meso-diaminopimelic acid. In strain K1-5T, menaquinone-7 (MK-7) is the predominant isoprenoid quinone and anteiso-C15 : 0 is the major cellular fatty acid. The DNA G+C content of strain K1-5T is 42.9 mol%. 16S rRNA gene-based phylogenetic analysis revealed that the strains exhibit levels of sequence similarity of less than 95.8 % to known Bacillus species. According to the polyphasic characterization, the strains represent a novel species, for which the name Bacillus aurantiacus sp. nov. is proposed. The type strain is K1-5T (=DSM 18675T =CCM 7447T =NCAIM B002265T).

Nocardioides daphniae sp. nov., isolated from Daphnia cucullata (Crustacea: Cladocera)

A Gram-positive, rod-shaped or coccoid, yellow-pigmented bacterial strain, D287(T), was isolated from the water flea Daphnia cucullata (Crustacea: Cladocera) collected from Lake Balaton in Hungary. Phylogenetic analysis on the basis of 16S rRNA gene sequence comparisons revealed that the strain represented a distinct lineage within the cluster of the genera Nocardioides and Marmoricola. The following characteristics were consistent with the affiliation of strain D287(T) to the genus Nocardioides: peptidoglycan based on LL-2,6-diaminopimelic acid, MK-8(H(4)) as the major menaquinone, iso-C(16:0) as the predominant cellular fatty acid, the presence of phosphatidylglycerol and diphosphatidylglycerol and a DNA G+C content of 69.9 mol%. Owing to characteristic differences in physiological traits and levels of 16S rRNA gene sequence similarity to its phylogenetically closest neighbours that were below 97%, strain D287(T) is considered to represent a novel species of the genus Nocardioides, for which the name Nocardioides daphniae sp. nov. is proposed. The type strain is D287(T) (=DSM 18664(T)=CCM 7403(T)).

Bacillus alkalisediminis sp. nov., an alkaliphilic and moderately halophilic bacterium isolated from sediment of extremely shallow soda ponds

Alkaliphilic strains characterized by optimal growth at pH 9.0 and 5 % (w/v) NaCl designated K1-25(T) and H3-93 were isolated from extremely shallow soda ponds located in Hungary. Cells of both strains were Gram-stain-positive, non-motile, straight rods and formed central, ellipsoidal endospores with swollen sporangia. The isolates were aerobic, catalase-positive, oxidase-negative and contained a peptidoglycan of type A1γ based on meso-diaminopimelic acid. In both strains, menaquinone-7 (MK-7) was the predominant isoprenoid quinone and the major cellular fatty acids were anteiso-C(15 : 0) and iso-C(15 : 0). The DNA G+C contents of strains K1-25(T) and H3-93 were 39.0 and 36.3 mol%, respectively. 16S rRNA gene sequence-based phylogenetic analysis revealed 99.2 % similarity between strains K1-25(T) and H3-93 and the novel isolates had the highest similarities to Bacillus akibai 1139(T) (97.8 and 98.3 %, respectively), Bacillus wakoensis N-1(T) (97.0 and 97.4 %), Bacillus okhensis Kh10-101(T) (97.1 and 97.4 %) and Bacillus krulwichiae AM31D(T) (96.9 and 97.1 %). DNA-DNA hybridization between our strains and the type strains of closely related Bacillus species was lower than 70 %. Although DNA-DNA hybridization between strains K1-25(T) and H3-93 was 27 %, the phenotypic and chemotaxonomic data did not support the differentiation of these two strains into separate species. Therefore, they represent genomovars of a novel species, for which the name Bacillus alkalisediminis sp. nov. is proposed. The type strain is K1-25(T) ( = DSM 21670(T)  = NCAIM B02301(T)).

Thermus composti sp. nov., isolated from oyster mushroom compost

A Gram-stain-negative, rod-shaped bacterium (strain K-39(T)) was isolated from the thermophilic phase of the composting process for oyster mushroom substrate preparation. The strain grew at 40-80 °C (optimum, 65-75 °C), at pH 5-9 (optimum, pH 7), in media containing up to 1.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain K-39(T) formed a distinct lineage within the genus Thermus. Its closest cultivated relative was Thermus islandicus PRI 3838(T) (96.8% similarity). The DNA G+C content of strain K-39(T) was 71.3 mol%. The new strain could be differentiated from the related taxa by not being able to hydrolyse starch. The predominant fatty acids of strain K-39(T) were iso-C(17:0) and anteiso-C(17:0). Strain K-39(T) contained a lower amount of the fatty acid iso-C(15:0) as compared to related species of the genus Thermus. The predominant respiratory quinone of the new isolate was menaquinone MK-8. On the basis of a taxonomic study using a polyphasic approach, strain K-39(T) is considered to represent a novel species of the genus Thermus, for which the name Thermus composti sp. nov. is proposed. The type strain is K-39(T) (=DSM 21686(T)=NCAIM B 02340(T)).

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)).

Arenimonas subflava sp. nov., isolated from a drinking water network, and emended description of the genus arenimonas

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 the class 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, measured by two different methods (52.0 mol% and 55.9 mol%, respectively), was much lower than that of any member of the genus Arenimonas. The predominant fatty acids (>8 %) were iso-C16:0, iso-C15:0, iso-C14:0, iso-C17:1ω9c and C16:1ω7c 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 of the genus Arenimonas, 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.

Zoogloea oleivorans sp. nov., a floc-forming, petroleum hydrocarbon-degrading bacterium isolated from biofilm.

A floc-forming, Gram-stain-negative, petroleum hydrocarbon-degrading bacterial strain, designated Buc(T), was isolated from a petroleum hydrocarbon-contaminated site in Hungary. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Buc(T) formed a distinct phyletic lineage within the genus Zoogloea. Its closest relative was found to be Zoogloea caeni EMB43(T) (97.2% 16S rRNA gene sequence similarity) followed by Zoogloea oryzae A-7(T) (95.9%), Zoogloea ramigera ATCC 19544(T) (95.5%) and Zoogloea resiniphila DhA-35(T) (95.4%). The level of DNA-DNA relatedness between strain Buc(T) and Z. caeni EMB43(T) was 31.6%. Cells of strain Buc(T) are facultatively aerobic, rod-shaped, and motile by means of a polar flagellum. The strain grew at temperatures of 5-35 °C (optimum 25-28 °C), and at pH 6.0-9.0 (optimum 6.5-7.5). The predominant fatty acids were C16:0, C10 : 0 3-OH, C12:0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The major respiratory quinone was ubiquinone-8 (Q-8) and the predominant polar lipid was phosphatidylethanolamine. The genomic DNA G+C content was 63.2 mol%. On the basis of the chemotaxonomic, molecular and phenotypic data, isolate Buc(T) is considered to represent a novel species of the genus Zoogloea, for which the name Zoogloea oleivorans sp. nov. is proposed. The type strain is Buc(T) ( =DSM 28387(T) =NCAIM B 02570(T)).

Bacterial communities in the gut of the freshwater copepod Eudiaptomus gracilis

Eudiaptomus gracilis is the most abundant member of the zooplankton, plays a key role in the food web of Lake Balaton (Hungary). In the present study the composition of bacterial communities of this copepod was investigated based on cultivation and molecular cloning. The cultivated bacterial strains from the gut homogenate samples of Eudiaptomus gracilis belonged to four different clades: Firmicutes, Actinobacteria, Bacteriodetes and Proteobacteria. Clone library showed high species diversity, Firmicutes, Actinobacteria, Proteobacteria, representatives of Deinococcus‐Thermus lineage and Cyanobacteria were detected. The isolated strains were very effective in degradation of different biopolymers. Many of the detected bacteria are known as opportunistic human or fish pathogens (Pseudomonas spp., Aeromonas spp., Chryseobacterium sp. and Staphylococcus sp.). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Nocardioides hungaricus sp. nov., isolated from a drinking water supply system

Three Gram-positive, rod-shaped bacterial strains were isolated from the drinking water supply system of the Hungarian capital, Budapest. Phylogenetic analysis on the basis of 16S rRNA gene sequence comparison revealed that the isolates represented a distinct cluster within the clade of the genus Nocardioides and were most closely related to Nocardioides pyridinolyticus OS4(T), Nocardioides aquiterrae GW-9(T), Nocardioides sediminis MSL-01(T) and N. hankookensis DS-30(T). The peptidoglycan based on LL-2,6-diaminopimelic acid, the major menaquinone MK-8(H₄), the cellular fatty acid profile with iso-C₁₆:₀ and anteiso-C₁₇:₀ as predominating components and the DNA G+C content of 71.4 mol% (strain 1RaM5-12(T)) were consistent with the affiliation of the isolates to the genus Nocardioides. Because of differences in physiological characteristics, matrix-assisted laser-desorption/ionization time-of-flight mass spectra of protein extracts, PvuII RiboPrinter patterns and 96.1 % 16S rRNA gene sequence similarity between strain 1RaM5-12(T) and its closest phylogenetic neighbour, N. pyridinolyticus OS4(T), a novel species, Nocardioides hungaricus sp. nov., is proposed. The type strain is 1RaM5-12(T) (=DSM 21673(T) =NCAIM 02330(T)).