Search results for "Proteobacteria"
showing 10 items of 152 documents
Relative Abundances of Proteobacterial Membrane-Bound and Periplasmic Nitrate Reductases in Selected Environments
2007
ABSTRACT Dissimilatory nitrate reduction is catalyzed by a membrane-bound and a periplasmic nitrate reductase. We set up a real-time PCR assay to quantify these two enzymes, using the narG and napA genes, encoding the catalytic subunits of the two types of nitrate reductases, as molecular markers. The narG and napA gene copy numbers in DNA extracted from 18 different environments showed high variations, with most numbers ranging from 2 × 10 2 to 6.8 × 10 4 copies per ng of DNA. This study provides evidence that, in soil samples, the number of proteobacteria carrying the napA gene is often as high as that of proteobacteria carrying the narG gene. The high correlation observed between narG an…
Hoeflea alexandrii sp. nov., isolated from the toxic dinoflagellate Alexandrium minutum AL1V
2006
A Gram-negative, aerobic, non-symbiotic bacterium (AM1V30(T)) was isolated from the toxic dinoflagellate Alexandrium minutum AL1V. On the basis of 16S rRNA gene sequence similarity, strain AM1V30(T) was most closely related (97.4 % similarity) to the type strain of Hoeflea marina, which belongs to the family Phyllobacteriaceae within the order Rhizobiales of the class Alphaproteobacteria. A polyphasic approach was used to clarify the taxonomic position of strain AM1V30(T). During the course of this study, a second species was described by others as belonging to the genus Hoeflea, namely Hoeflea phototrophica; it showed a somewhat higher level of 16S rRNA gene sequence similarity with respec…
Thalassobacter stenotrophicus gen. nov., sp. nov., a novel marine alpha-proteobacterium isolated from Mediterranean sea water.
2005
A Gram-negative, slightly halophilic, strictly aerobic, chemo-organotrophic bacterium was isolated from Mediterranean sea water near Valencia (Spain). 16S rRNA gene sequence comparisons showed that the isolate represented a separate branch within the α-3 subclass of the Proteobacteria, now included within the order ‘Rhodobacterales’. Jannaschia helgolandensis was the closest relative, but their low sequence similarity and other features indicated that they were not related at the genus level. Isolate 5SM22T produced bacteriochlorophyll a and grew on solid media as regular salmon-pink colonies. Cells are motile rods, with polar flagella. The DNA G+C content is 59·1 mol%. Morphological, physi…
Novosphingobium lentum sp. nov., a psychrotolerant bacterium from a polychlorophenol bioremediation process
2005
A polychlorophenol-degrading strain, designated MT1T, and three MT1-like strains, MT101, MT103 and MT104, were isolated from a cold (4–8 °C) fluidized-bed process treating chlorophenol-contaminated groundwater in southern Finland. The organisms were Gram-negative, rod-shaped, catalase-positive, non-spore-forming and non-motile. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strains belonged to the α-4 subclass of the Proteobacteria and were members of the genus Novosphingobium. The highest 16S rRNA gene sequence similarity observed for these strains was 96·5 % with the type strains of Novosphingobium hassiacum, Novosphingobium aromaticivorans and Novosphingobium s…
Neptuniibacter caesariensis gen. nov., sp. nov., a novel marine genome-sequenced gammaproteobacterium.
2007
7 pages, 1 figure, 1 table
Reinekea blandensis sp. nov., a marine, genome-sequenced gammaproteobacterium
2007
6 pages, 2 figures, 2 tables
How Does Tremblaya princeps Get Essential Proteins from Its Nested Partner Moranella endobia in the Mealybug Planoccocus citri?
2013
International audience; Many insects maintain intracellular mutualistic symbiosis with a wide range of bacteria which are considered essential for their survival (primary or P-endosymbiont) and typically suffer drastic genome degradation. Progressive loss of P-endosymbiont metabolic capabilities could lead to the recruitment of co-existent facultative endosymbiont (secondary or S-endosymbiont), thus adding more complexity to the symbiotic system. Planococcus citri, among other mealybug species, harbors an unconventional nested endosymbiotic system where every Tremblaya princeps cell (beta-proteobacterium) harbors many Moranella endobia cells (gamma-proteobacterium). In this system, T. princ…
Genetic diversity and phenotypic characterization of Iodobacter limnosediminis associated with skin lesions in freshwater fish
2021
The relatively unknown genus Iodobacter sp. has been repeatedly isolated from skin ulcers and saprolegniosis on freshwater fish in Finland, especially farmed salmonids. Genetic characterization verified that all 23 bacterial isolates studied here belonged to the species Iodobacter limnosediminis, previously undescribed from the fish microbiota. Whole-genome pulsed-field gel electrophoresis revealed variability between the I. limnosediminis strains, suggesting that they were most likely of environmental origin. Two I. limnosediminis strains caused lesions in 27%–53% of brown trout (Salmo trutta) injected intramuscularly (p ≤ .05). The lesions represented moderate to severe tissue damage, but…
Haliea mediterranea sp. nov., a marine gammaproteobacterium.
2010
Strain 7SM29T, an aerobic marine gammaproteobacterium isolated from seawater from Castellón, Spain, was characterized by classical phenotyping, chemotaxonomy and 16S rRNA gene sequence analysis. Strain 7SM29T was found to be closely related to strains in the genus Haliea and to Congregibacter litoralis KT71T, with which a genus-level cluster was formed within the NOR5/OM60 clade of the Gammaproteobacteria. Strain 7SM29T was a short, motile rod with a tuft of three polar flagella. The strain grew on marine agar and formed pale-yellow colonies. Strain 7SM29T required NaCl for growth, reduced nitrate to nitrite, degraded several polymers and showed a preference for organic acids and amino acid…
Development of a specific assay using RISA for detection of the bacterial agent of 'basses richesses' syndrome of sugar beet and confirmation of a Pe…
2007
International audience; A technique for the specific diagnosis in insects of SBRp (the γ-3 proteobacterium associated with the syndrome ‘basses richesses’ (SBR) of sugar beet crops in eastern France), using the RISA (rDNA intergenic spacer analysis) technique, was developed. PCR using the Alb1/Oliv1 primer pair specifically amplified a 16S-ITS region of SBRp and produced a characteristic DNA fingerprint. This PCR assay did not detect other closely related organisms, including the Arsenophonus endosymbiont of Diaphorina citri, the secondary endosymbiont of Glycaspis brimblecombei, or ‘Candidatus Phlomobacter fragariae’, a related phytopathogenic γ-3 proteobacterium. Six different ribosomal o…