Papers by Svetlana Fridman
International journal of systematic and evolutionary microbiology, 2012
Pseudomonas flectens (Johnson 1956), a plant pathogenic bacterium on the pods of the French bean,... more Pseudomonas flectens (Johnson 1956), a plant pathogenic bacterium on the pods of the French bean, is not considered to be a member of the genus Pseudomonas sensu stricto. A polyphasic approach that included phenotypic properties and phylogenetic analysis based on 16S rRNA, rpoB and atpD gene sequences supported the transfer of Pseudomonas flectens, Johnson 1956 to a novel genus in the Enterobacteriaceae family as Phaseolibacter flectens comb. nov. Two strains of Phaseolibacter flectens were studied (ATCC 12775T and LMG 2186). The strains shared 99.8% sequence similarities in their 16SrRNA gene and the housekeeping genes were identical. Phaseolibacter flectens shared 96.6% sequence similarities, or less, with species from different genera in the Enterobacteriaceae family and only 84.7% sequence similarities with Pseudomonas aeruginosa LMG 1242T, demonstrating that it is not related to the genus Pseudomonas. As Phaseolibacter flectens formed an independent phyletic lineage in all the ...
Environmental Microbiology Reports, 2012
Floral nectar is regarded as the most important reward available to animal-pollinated plants to a... more Floral nectar is regarded as the most important reward available to animal-pollinated plants to attract pollinators. Despite the vast amount of publications on nectar properties, the role of nectar as a natural bacterial habitat is yet unexplored. To gain a better understanding of bacterial communities inhabiting floral nectar, culture-dependent and -independent (454-pyrosequencing) methods were used. Our findings demonstrate that bacterial communities in nectar are abundant and diverse. Using culturedependent method we showed that bacterial communities of nectar displayed significant variation among three plant species: Amygdalus communis, Citrus paradisi and Nicotiana glauca. The dominant class in the nectar bacterial communities was Gammaproteobacteria. About half of the isolates were novel species (< 97% similarities of the 16S rRNA gene with known species). Using 454-pyrosequencing we demonstrated that nectar microbial community are distinct for each of the plant species while there are no significant differences between nectar microbial communities within nectars taken from different plants of the same species. Primary selection of the nectar bacteria is unclear; it may be affected by variations in the chemical composition of the nectar in each plant. The role of the rich and diverse nectar microflora in the attraction-repulsion relationships between the plant and its nectar consumers has yet to be explored.
Current Microbiology, 2013
The phyllosphere is one of the largest habitats for terrestrial microorganisms. To gain a better ... more The phyllosphere is one of the largest habitats for terrestrial microorganisms. To gain a better insight into the factors underlying the composition of bacterial communities inhabiting leaf surfaces we performed culturedependent and independent (Denaturing Gradient Gel Electrophoresis) analyses on the bacteria associated with the leaves of three plant species: Amygdalus communis, Citrus paradisi, and Nicotiana glauca. We found that the culturable classes Bacilli and Actinobacteria were the predominant classes on the phyllosphere of all three plant species. In contrast to this consistency on the bacterial class level, we found a significant variation on the bacterial species-level based on the culturable methods. Although some variation was detected among individual plants within one plant species, the inter-specific variability exceeded the intra-specific variability. C. paradisi leaf surface had the highest predicted total species richness (Chao 2 and ICE) and the highest species diversity (bw) among the three plant species. Our findings demonstrate that environmental conditions, mainly the plant species within a site, govern the bacterial community composition on leaf surfaces.
Summary Floral nectar is regarded as the most important reward available to animal-pollinated pla... more Summary Floral nectar is regarded as the most important reward available to animal-pollinated plants to attract pollinators. Despite the vast amount of publications on nectar properties, the role of nectar as a natural bacterial habitat is yet unexplored. To gain a better understanding of bacterial communities inhabiting floral nectar, culture-dependent and-independent (454-pyrosequencing) methods were used. Our findings demonstrate that bacterial communities in nectar are abundant and diverse. Using culturedependent ...
Rosenbergiella nectarea gen. nov., sp. nov., in the family Enterobacteriaceae, isolated from flor... more Rosenbergiella nectarea gen. nov., sp. nov., in the family Enterobacteriaceae, isolated from floral nectar Gram-negative, rod-shaped, oxidase-negative, facultatively anaerobic, yellow-orange-pigmented and motile bacterial strains, designated 8N4 T , 9N2 and 10N3, were isolated from flower nectar of Amygdalus communis (almond) and Citrus paradisi (grapefruit). The 16S rRNA gene sequences of the strains shared highest sequence similarity of 97.0 % with that of Phaseolibacter flectens ATCC 12775 T and lower similarity with sequences from other type strains of genera of the Enterobacteriaceae. A polyphasic approach that included determination of phenotypic properties and phylogenetic analysis based on 16S rRNA, gyrB, rpoB and atpD gene sequences supported the classification of strains 8N4 T , 9N2 and 10N3 within a novel species in a novel genus in the family Enterobacteriaceae. Strain 8N4 T , and the reference strains of the novel species, grew at 4-35 6C (optimum, 28-30 6C), with 0-5.0 % NaCl (optimum, 3 % NaCl) and with 0-60 % sucrose (optimum, 10-25 % sucrose). Their major cellular fatty acids were C 16 : 0 , C 17 : 0 cyclo, C 18 : 1 v7c and summed feature 3 (C 16 : 1 v7c and/or iso-C 15 : 0 2-OH). The DNA G+C content of strain 8N4 T was 46.8 mol%. On the basis of phenotypic properties and phylogenetic distinctiveness, the floral nectar isolates are classified within a novel species in a new genus in the family Enterobacteriaceae, for which the name Rosenbergiella nectarea gen. nov., sp. nov. is proposed. The type strain of Rosenbergiella nectarea is 8N4 T (5LMG 26121 T 5DSM 24150 T ).
The ISME Journal, 2012
Cyanobacteria have a key role in marine photosynthesis, which contributes to the global carbon cy... more Cyanobacteria have a key role in marine photosynthesis, which contributes to the global carbon cycle and to the world oxygen supply. Genes encoding for photosystem-II (PSII) and photosystem-I (PSI) reaction centers are found in different cyanophage genomes, and it was suggested that the horizontal transfer of these genes might be involved in increasing phage fitness. We have further analyzed a rare viral Global Ocean Sampling (GOS) clone containing PSI genes. This clone contains the unusual PSI gene organization psaD-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;C-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;A, as opposed to the more frequently observed viral psaJF-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;C-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;A-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;B-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;K-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;E-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;D organization, and was detected only once in the GOS metagenome. Our analyses identified more occurrences with similar arrangement and indicate that this PSI viral gene organization (now psaD-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;C-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;A-&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;B), although rare, is authentic and represents a new PSI gene arrangement.
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Papers by Svetlana Fridman