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1.  Dehalogenimonas spp. can Reductively Dehalogenate High Concentrations of 1,2-Dichloroethane, 1,2-Dichloropropane, and 1,1,2-Trichloroethane 
AMB Express  2012;2:54.
The contaminant concentrations over which type strains of the species Dehalogenimonas alkenigignens and Dehalogenimonas lykanthroporepellens were able to reductively dechlorinate 1,2-dichloroethane (1,2-DCA), 1,2-dichloropropane (1,2-DCP), and 1,1,2-trichloroethane (1,1,2-TCA) were evaluated. Although initially isolated from an environment with much lower halogenated solvent concentrations, D. alkenigignens IP3-3T was found to reductively dehalogenate chlorinated alkanes at concentrations comparable to D. lykanthroporepellens BL-DC-9T. Both species dechlorinated 1,2-DCA, 1,2-DCP, and 1,1,2-TCA present at initial concentrations at least as high as 8.7, 4.0, and 3.5 mM, respectively. The ability of Dehalogenimonas spp. to carry out anaerobic reductive dechlorination even in the presence of high concentrations of chlorinated aliphatic alkanes has important implications for remediation of contaminated soil and groundwater.
PMCID: PMC3492069  PMID: 23046725
Bioremediation; Chlorinated alkanes; Dehalogenimonas; Reductive dechlorination; Dehalogenation
2.  Complete genome sequence of Dehalogenimonas lykanthroporepellens type strain (BL-DC-9T) and comparison to “Dehalococcoides” strains 
Standards in Genomic Sciences  2012;6(2):251-264.
Dehalogenimonas lykanthroporepellens is the type species of the genus Dehalogenimonas, which belongs to a deeply branching lineage within the phylum Chloroflexi. This strictly anaerobic, mesophilic, non spore-forming, Gram-negative staining bacterium was first isolated from chlorinated solvent contaminated groundwater at a Superfund site located near Baton Rouge, Louisiana, USA. D. lykanthroporepellens was of interest for genome sequencing for two reasons: (a) an unusual ability to couple growth with reductive dechlorination of environmentally important polychlorinated aliphatic alkanes and (b) a phylogenetic position that is distant from previously sequenced bacteria. The 1,686,510 bp circular chromosome of strain BL-DC-9T contains 1,720 predicted protein coding genes, 47 tRNA genes, a single large subunit rRNA (23S-5S) locus, and a single, orphan, small subunit rRNA (16S) locus.
PMCID: PMC3387798  PMID: 22768368
reductive dechlorination; groundwater; strictly anaerobic; hydrogen utilization; contamination; Chloroflexi
3.  Detection and Quantification of Dehalogenimonas and “Dehalococcoides” Populations via PCR-Based Protocols Targeting 16S rRNA Genes▿ †  
Applied and Environmental Microbiology  2009;75(23):7560-7564.
Members of the haloalkane dechlorinating genus Dehalogenimonas are distantly related to “Dehalococcoides” but share high homology in some variable regions of their 16S rRNA gene sequences. In this study, primers and PCR protocols intended to uniquely target Dehalococcoides were reevaluated, and primers and PCR protocols intended to uniquely target Dehalogenimonas were developed and tested. Use of the genus-specific primers revealed the presence of both bacterial groups in groundwater at a Louisiana Superfund site.
PMCID: PMC2786429  PMID: 19820163
4.  A New Lineage of Halophilic, Wall-Less, Contractile Bacteria from a Brine-Filled Deep of the Red Sea▿  
Journal of Bacteriology  2008;190(10):3580-3587.
A novel strictly anaerobic bacterium designated strain SSD-17BT was isolated from the hypersaline brine-sediment interface of the Shaban Deep, Red Sea. Cells were pleomorphic but usually consisted of a central coccoid body with one or two “tentacle-like” protrusions. These protrusions actively alternated between a straight, relaxed form and a contracted, corkscrew-like one. A peptidoglycan layer was not detected by electron microscopy. The organism forms “fried-egg”-like colonies on MM-X medium. The organism is strictly anaerobic and halophilic and has an optimum temperature for growth of about 30 to 37°C and an optimum pH of about 7. Nitrate and nitrite are reduced; lactate is a fermentation product. The fatty acid profile is dominated by straight saturated and unsaturated chain compounds. Menaquinone 4 is the major respiratory quinone. Phylogenetic analysis demonstrated strain SSD-17BT represents a novel and distinct lineage within the radiation of the domain Bacteria. The branching position of strain SSD-17BT was equidistant to the taxa considered to be representative lineages of the phyla Firmicutes and Tenericutes (with its sole class Mollicutes). The phenotypic and phylogenetic data clearly show the distinctiveness of this unusual bacterium, and we therefore propose that strain SSD-17BT (= DSM 18853 = JCM 14575) represents a new genus and a new species, for which we recommend the name Haloplasma contractile gen. nov., sp. nov. We are also of the opinion that the organism represents a new order-level taxon, for which we propose the name Haloplasmatales.
PMCID: PMC2394993  PMID: 18326567
6.  Extensive Diversity of Ionizing-Radiation-Resistant Bacteria Recovered from Sonoran Desert Soil and Description of Nine New Species of the Genus Deinococcus Obtained from a Single Soil Sample†  
The ionizing-radiation-resistant fractions of two soil bacterial communities were investigated by exposing an arid soil from the Sonoran Desert and a nonarid soil from a Louisiana forest to various doses of ionizing radiation using a 60Co source. The numbers of surviving bacteria decreased as the dose of gamma radiation to which the soils were exposed increased. Bacterial isolates surviving doses of 30 kGy were recovered from the Sonoran Desert soil, while no isolates were recovered from the nonarid forest soil after exposure to doses greater than 13 kGy. The phylogenetic diversities of the surviving culturable bacteria were compared for the two soils using 16S rRNA gene sequence analysis. In addition to a bacterial population that was more resistant to higher doses of ionizing radiation, the diversity of the isolates was greater in the arid soil. The taxonomic diversity of the isolates recovered was found to decrease as the level of ionizing-radiation exposure increased. Bacterial isolates of the genera Deinococcus, Geodermatophilus, and Hymenobacter were still recovered from the arid soil after exposure to doses of 17 to 30 kGy. The recovery of large numbers of extremely ionizing-radiation-resistant bacteria from an arid soil and not from a nonarid soil provides further ecological support for the hypothesis that the ionizing-radiation resistance phenotype is a consequence of the evolution of other DNA repair systems that protect cells against commonly encountered environmental stressors, such as desiccation. The diverse group of bacterial strains isolated from the arid soil sample included 60 Deinococcus strains, the characterization of which revealed nine novel species of this genus.
PMCID: PMC1214641  PMID: 16151108
7.  Gamma-Proteobacteria Aquicella lusitana gen. nov., sp. nov., and Aquicella siphonis sp. nov. Infect Protozoa and Require Activated Charcoal for Growth in Laboratory Media 
Applied and Environmental Microbiology  2003;69(11):6533-6540.
Several isolates, belonging to two new species of the same novel genus of gamma-proteobacteria, were recovered from drilled well (borehole) and spa water at São Gemil in central Portugal. These organisms are phylogenetically most closely related to the strictly intracellular uncultured species of the genus Rickettsiella, which cause disease in arthropods, and to the facultatively intracellular species of the genus Legionella, some of which cause Legionnaires' disease and Pontiac fever. The São Gemil strains grew only on media containing charcoal, as is also true of the species of the genus Legionella. Unlike the vast majority of Legionella isolates, the new isolates did not require l-cysteine or ferric pyrophosphate for growth but like the legionellae had an absolute requirement for α-ketoglutarate. Strains SGT-39T and SGT-56 grew consistently between 30 and 43°C, while strains SGT-108T and SGT-109 grew between 30 and 40°C. The pH ranges for growth of these organisms were surprisingly narrow: strains SGT-39T and SGT-56 grew between pH 6.3 and 7.3, while strains SGT-108T and SGT-109 grew between pH 6.3 and 7.0. Both organisms proliferated in the amoeba Hartmannella vermiformis but did not grow in U937 human cells. Based on 16S rRNA gene sequence analysis and physiological, biochemical, and chemical analysis we describe two new species of one novel genus; one species is represented by strain SGT-39T, for which we propose the name Aquicella lusitana, while strain SGT-108T represents a second species of the same genus, for which we propose the name Aquicella siphonis.
PMCID: PMC262295  PMID: 14602611
9.  Albidovulum inexpectatum gen. nov., sp. nov., a Nonphotosynthetic and Slightly Thermophilic Bacterium from a Marine Hot Spring That Is Very Closely Related to Members of the Photosynthetic Genus Rhodovulum 
Several bacterial isolates, with an optimum growth temperature of about 50°C, were recovered from the marine hot spring at Ferraria on the island of São Miguel in the Azores. The geothermal water emerged from a porous lava flow and rapidly cooled in contact with seawater except at low tide. The bacterial species represented by strains FRR-10T and FRR-11 was nonpigmented, strictly aerobic, and organotrophic. Several genes, bchZ, pufB, pufA, pufL, or pufM, encoding the photosynthetic reaction center proteins and the core light-harvesting complexes were not detected in these strains. The organism oxidized thiosulfate to sulfate with enhancement of growth. The organism did not require additional NaCl in the culture medium for growth, but NaCl at 1.0% enhanced growth. Phylogenetic analyses using the 16S rRNA gene sequence of strain FRR-10T indicated that the new organism represented a new species of the α-3 subclass of the Proteobacteria and that it branches within the species of the genus Rhodovulum. The contradiction of classifying an organism which branches within the radiation of the genus Rhodovulum but does not possess the hallmark characteristics of this genus is discussed. However, the absence of several of these characteristics, namely, the lack of photosynthesis and pigmentation, which could be related to colonization of dark environments, and growth at high temperatures, leads to our proposal that strains FRR-10T and FRR-11 should be classified as a new species of a novel genus, Albidovulum inexpectatum, representing, at present, the most thermophilic organism within the α-3 subclass of the Proteobacteria.
PMCID: PMC124098  PMID: 12200275

Results 1-9 (9)