Phreatobacter oligotrophus gen. nov., sp. nov., an alphaproteobacterium isolated from ultrapure water of the water purification system of a power plant.

Strains of a novel alphaproteobacterium were isolated from ultrapure water of a Hungarian power plant on a newly developed medium. Phylogenetic analysis of the 16S rRNA gene sequences of the novel 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_21(T) exhibited the highest sequence similarity to Bosea minatitlanensis AMX51(T) (93.43 %) and Bosea thiooxidans DSM 9653(T) (93.36 %); similarity to all other taxa was less than 93.23 %. Fatty acid profiles, matrix-assisted laser-desorption/ionization time-of-flight mass spectra of cell extracts as well as physiological and biochemical characteristics indicated that our strains represent a novel genus and species within the class Alphaproteobacteria. The major isoprenoid quinone of the strains was Q-10, the major cellular fatty acids were C18 : 1ω7c and 11-methyl C18 : 1ω7c and the polar lipid profiles of the strains contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and several unknown phospholipids and other lipids. The characteristic diamino acid in their cell wall was meso-diaminopimelic acid. The G+C content of DNA of the proposed type strain PI_21(T) was 68.9 mol%. A new genus and species, Phreatobacter oligotrophus gen. nov., sp. nov., is proposed to accommodate the strains. Strain PI_21(T) ( = DSM 25521(T) = NCAIM B 02510(T)) is the type strain of Phreatobacter oligotrophus.

Aquipuribacter hungaricus gen. nov., sp. nov., an actinobacterium isolated from the ultrapure water system of a power plant.

A Gram-positive actinobacterium, strain IV-75(T), was isolated by using R2A agar from the ultrapure water system of a power plant in Hungary. The strain exhibited a rod-coccus cell cycle, and was strictly aerobic, non-motile, catalase-positive and oxidase-negative. 16S rRNA gene sequence analysis revealed that strain IV-75(T) belonged to the suborder Micrococcineae and clustered with members of the family Intrasporangiaceae. Its closest phylogenetic neighbour was Arsenicicoccus bolidensis CCUG 47306(T) (94.3% 16S rRNA gene sequence similarity). The peptidoglycan of strain IV-75(T) contained meso-diaminopimelic acid and MK-10(H(4)) was the major menaquinone. The polar lipid pattern contained phosphatidylglycerol, two unidentified phospholipids, one glycolipid and several other lipid components. The major fatty acids were anteiso-C(15:0), C(18:1)ω9c and C(16:0). Based on the moderate levels of 16S rRNA gene sequence similarity to all members of the family Intrasporangiaceae and the unique combination of chemotaxonomic characteristics, strain IV-75(T) is considered to represent a novel species of a new genus, for which the name Aquipuribacter hungaricus gen. nov., sp. nov. is proposed. The type strain of Aquipuribacter hungaricus is IV-75(T) (=DSM 21674(T)=NCAIM B 02333(T)).

Diversity and activity of cultivable aerobic planktonic bacteria of a saline Lake located in Sovata, Romania.

Aerobic bacterial strains from the salt water of Lake Red (Sovata, Romania) were cultivated. More than half of the 80 strains were G(-) and formed motile straight rods. Only a few strains produced acid from D-glucose and reduced nitrate to nitrite. Optimum NaCl concentration for growth varied between 5 and 15 % in the majority of the strains, so the isolates were regarded moderately halophilic. On the basis of the 16S rRNA gene sequence similarity almost half of the strains were identified as members of genus Halomonas. Other strains belonged to genera Marinobacter, Psychrobacter, Serratia, Morganella (γ-Proteobacteria), Bacillus, Exiguobacterium, Planococcus (Firmicutes), and Arthrobacter, Micrococcus, Microbacterium, and Nesterenkonia (Actinobacteria).

Bacteria isolated from the different developmental stages and larval organs of the obligate parasitic fly, Wohlfahrtia magnifica (Diptera: Sarcophagidae).

Wohlfahrtia magnifica (Diptera: Sarcophagidae) is the major myiasis-causing fly species in the whole of Eurasia for most important domestic animals. The aim of the present work was to obtain data on the culturable bacteria isolated under aerobic conditions from this fly: bacteria were isolated from all developmental stages (larvae, pupa, and imago) of Wohlfahrtia magnifica, and the third-stage larval organs were also sampled. To determine the possible antagonistic effects between the dominant bacterial groups, an antibiosis assay was carried out. Plating and isolation of bacteria was performed by classical microbiological methods. Characterization of the isolated strains was carried out via a polyphasic approach; classical phenotypic tests, chemotaxonomical examinations, and 16S rDNA sequence analyses were also applied. In the case of maggot macerate samples, members of the family Enterobacteriaceae were characteristic. Members of a new genus (Schineria) belonging to the gamma subdivision of proteobacteria were also isolated. According to our data, the shifts in the Schineria and Proteus populations within the larvae are strongly influenced by their interactions with each other and among the members of the family Enterobacteriaceae. The pupa and imago samples contained several other Gram-negative bacteria (Stenotrophomonas, Brevundimonas, etc.). Among Gram-positive bacteria, in all maggot macerate samples, members of the genus Bacillus and the Arthrobacter-Micrococcus group of actinobacteria were dominant (neither of them was a producer or sensitive to the compounds of other microorganisms), and bacteria related to the genus Corynebacterium were also found. From the larvae Aureobacterium liquefaciens and Enterococcus faecalis were isolated, and from the pupae Dietzia maris and Enterococcus faecalis. In the samples of third-stage larval organs, the dominant groups were the same as in the third-stage larval macerate sample; however, several additional genera/species were observed (Rhodococcus fascians, Streptomyces sp., Rathayibacter sp., Bacillus thuringiensis/cereus).

Diversity of alkaliphilic and alkalitolerant bacteria cultivated from decomposing reed rhizomes in a Hungarian soda lake.

Bacterial communities associated with decomposing rhizomes of Phragmites australis were investigated in Lake Ferto (Neusiedlersee, Hungary). Alkaliphilic and alkalitolerant strains were isolated on cellulose-containing alkaline medium spread with dilutions of scrapings taken from the surface of the decaying plant material. Fifty-one strains were grouped by numerical analysis based on physiological tests and BIOLOG sole carbon source utilization data. The strains identified by 16S rDNA sequence comparisons included members of low G+C Gram positives (Marinibacillus marinus, Bacillus cereus, and Exiguobacterium aurantiacum), high G+C Gram positives (Nesterenkonia halobia and Dietzia natronolimnea), alpha-proteobacteria (Pannonibacter phragmitetus), and gamma-proteobacteria (Pseudomonas pseudoalcaligenes and Halomonas venusta). Most of the strains were characterized by aerobic chemoorganotrophic respiratory metabolism and utilized several different carbon sources, although no direct cellulolytic activity was observed. Results of the pH and salt tolerance tests revealed optimuma in most cases at pH 11 and at the presence of 2.5-5% NaCl. These bacteria probably occupy niches in the aerobic, alkaline, water-influenced environments on the decomposing reed surfaces.

Comparative studies on Aeromonas strains isolated from Lakes Balaton (Hungary) and Fertó/Neusiedlersee (Hungary).

Ecological and comparative taxonomic investigations were carried out on 49 Aeromonas strains isolated from water samples of two moderately alkaline lakes of Hungary, Lake Balaton and Lake Fertó/Neusiedlersee together with 3 authentic strains of Aeromonas hydrophila. Five phena were created at greater than 92% similarity value using the UPGMA method with the Jaccard coefficient. Strains isolated from Lake Balaton were determined as A. hydrophila, while strains originated from Lake Fertó were identified as A. hydrophila and A. sobria. The Fertó isolates of A. hydrophila grew only at higher salt concentration (5% NaCl). This might be an adaptation to the higher salt contents in the water of Lake Fertó. However, no specific differences were detected in their behaviour against alkaline pH values. The wide range of their degradative enzymes indicate that aeromonads can play an important role in nutrient cycling.