Publications by authors named "Diliana D Simeonova"

Graphene oxide (GO) and graphene-based materials (GBMs) have gained over the last two decades considerable attention due to their intrinsic physicochemical properties and their applications. Besides, a lot of concern regarding the potential toxicity of GBMs has emerged. One of the aspects of concern is the interactions between GBMs and different environmental compartments, especially indigenous microbial and, in particular, bacterial communities.

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We present here the 5.561-Mbp assembled draft genome sequence of subsp. ATCC 9621, a phosphite- and organophosphonate-assimilating Gammaproteobacterium.

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We present the first 3.315-Mbp assembled draft genome sequence of Flavobacterium succinicans strain DD5b. This bacterium is a phosphite-assimilating representative of the genus Flavobacterium isolated from guts of the zooplankton Daphnia magna.

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Shinella sp. strain DD12, a novel phosphite assimilating bacterium, has been isolated from homogenized guts of 4 days starved zooplankton Daphnia magna. Here we report the draft genome of this bacterium, which comprises 7,677,812 bp and 7505 predicted protein-coding genes.

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The phosphite assimilating bacterium, P. glucosidilyticus DD6b, was isolated from the gut of the zooplankton Daphnia magna. Its 3,872,381 bp high-quality draft genome is arranged into 93 contigs containing 3311 predicted protein-coding and 41 RNA-encoding genes.

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We report the draft genome sequence of Serratia sp. strain DD3, a gammaproteobacterium from the family Enterobacteriaceae. It was isolated from homogenized guts of Daphnia magna.

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Here, we report the draft genome sequence of the methanotrophic gammaproteobacterium Methyloglobulus morosus DSM 22980 strain KoM1, which is proposed to be the type species for the novel genus Methyloglobulus. The genome (4.143 Mb) consists of a single circular chromosome and harbors genes for 2-aminoethylphosphonate (ciliatine) biosynthesis.

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Background: The Delta-Proteobacterium Desulfotignum phosphitoxidans is a type strain of the genus Desulfotignum, which comprises to date only three species together with D. balticum and D. toluenicum.

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We report the 5.008-Mbp assembled draft genome sequence of Desulfotignum phosphitoxidans strain FiPS-3 (DSM 13687), which gains metabolic energy from the oxidation of phosphite to phosphate. Its genome provides insights into the composition and architecture of the phosphite-utilizing and energy-transducing systems required to live with phosphite as electron donor.

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Desulfotignum phosphitoxidans is a strictly anaerobic, Gram-negative bacterium that utilizes phosphite as the sole electron source for homoacetogenic CO2 reduction or sulfate reduction. A genomic library of D. phosphitoxidans, constructed using the fosmid vector pJK050, was screened for clones harboring the genes involved in phosphite oxidation via PCR using primers developed based on the amino acid sequences of phosphite-induced proteins.

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We present here a new approach that enabled the identification of a new protein from a bacterial strain with unknown genomic background using a combination of inverted PCR with degenerate primers derived from N-terminal protein sequences and high resolution peptide mass determination of proteolytic digests from two-dimensional electrophoretic separation. Proteins of the sulfate-reducing bacterium Desulfotignum phosphitoxidans specifically induced in the presence of phosphite were separated by two-dimensional gel electrophoresis as a series of apparent soluble and membrane-bound isoforms with molecular masses of approximately 35 kDa. Inverted PCR based on N-terminal sequences and high resolution peptide mass fingerprinting by Fourier transform-ion cyclotron resonance mass spectrometry provided the identification of a new NAD(P) epimerase/dehydratase by specific assignment of peptide masses to a single ORF, excluding other possible ORF candidates.

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Microbial biotransformations have a major impact on contamination by toxic elements, which threatens public health in developing and industrial countries. Finding a means of preserving natural environments-including ground and surface waters-from arsenic constitutes a major challenge facing modern society. Although this metalloid is ubiquitous on Earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized.

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An arsenite-oxidizing bacterium, designated strain ULPAs1(T), was isolated from industrial sludge heavily contaminated with arsenic. Cells of this isolate were Gram-negative, curved rods, motile by means of a polar flagellum. The strain was positive for oxidase and catalase activities, was able to reduce nitrate to nitrite, used acetate, lactate and peptone as organic carbon sources under aerobic conditions and was able to oxidize arsenite (As[III]) to arsenate (As[V]).

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Arsenic is one of the major groundwater contaminants worldwide. It was previously demonstrated that the beta-proteobacterium Cenibacterium arsenoxidans has an efficient As[III] oxidation ability. The present study was conducted to evaluate the performance of alginate-immobilized ULPAs1 in the oxidation of As[III] to As[V] in batch reactors.

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An efficient, inexpensive microplate colorimetric assay for screening of bacteria which can be used in bioremediation of arsenic was developed. The assay is based on the colorimetric analysis of the precipitates formed upon reaction of silver nitrate with arsenic. The method proved reliable and sensitive for the detection of As[III] oxidizers and As[V] reducers and can be used over a large pH range (5.

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The beta-proteobacterial strain ULPAs1, isolated from an arsenic-contaminated environment, is able to efficiently oxidize arsenite [As(III)] to arsenate [As(V)]. Mutagenesis with a lacZ-based reporter transposon yielded two knockout derivatives deficient in arsenite oxidation. Sequence analysis of the DNA flanking the transposon insertions in the two mutants identified two adjacent open reading frames, named aoxA and aoxB, as well as a putative promoter upstream of the aoxA gene.

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