Deinococcus yunweiensis sp. nov., a gamma- and UV-radiation-resistant bacterium from China

Environmental distribution and genomic characteristics of Solirubrobacter, with proposal of two novel species

Solirubrobacter spp. were abundant in soil samples collected from deserts and other areas with high UV radiation. In addition, a novel Solirubrobacter species, with strain CPCC 204708T as the type, was isolated and identified from sandy soil sample collected from the Badain Jaran Desert of the Inner Mongolia autonomous region. Strain CPCC 204708T was Gram-stain positive, rod-shaped, non-motile, non-spore-forming, and grew optimally at 28-30°C, pH 7.0-8.0, and in the absence of NaCl. Analysis of the 16S rRNA gene sequence of strain CPCC 204708T showed its identity within the genus Solirubrobacter, with highest nucleotide similarities (97.4-98.2%) to other named Solirubrobacter species. Phylogenetic and genomic analyses indicated that the strain was most closely related to Solirubrobacter phytolaccae KCTC 29190T, while represented a distinct species, as confirmed from physiological properties and comparison. The name Solirubrobacter deserti sp. nov. was consequently proposed, with CPCC 204708T (= DSM 105495T = NBRC 112942T) as the type strain. Genomic analyses of the Solirubrobacter spp. also suggested that Solirubrobacter sp. URHD0082 represents a novel species, for which the name Candidatus "Solirubrobacter pratensis" sp. nov. was proposed. Genomic analysis of CPCC 204708T revealed the presence of genes related to its adaptation to the harsh environments of deserts and may also harbor genes functional in plant-microbe interactions. Pan-genomic analysis of available Solirubrobacter spp. confirmed the presence of many of the above genes as core components of Solirubrobacter genomes and suggests they may possess beneficial potential for their associate plant and may be important resources for bioactive compounds.

Deinococcus aestuarii sp. nov. and Deinococcus aquaedulcis sp. nov., two novel resistant bacteria isolated from pearl river estuary

Two novel species of the genus Deinococcus, designated SYSU M49105^T and SYSU M42101^T, were isolated from freshwater samples of the Pearl River estuary in Guangdong, China. Phylogenetic analysis using 16S rRNA gene sequence indicated that strains SYSU M49105^T and SYSU M42101^T showed the highest sequence similarities to Deinococcus aetherius JCM 11751 ^T (93.6%) and Deinococcus multiflagellatus NBRC 112888 ^T (97.3%), respectively. Cells of both strains were Gram-staining positive, aerobic, coccus-shaped, oxidase-negative and non-motile. The cell wall contained meso-diaminopimelic acid as their diagnostic diamino acid. MK-8 was the predominant respiratory quinone for both strains. The polar lipid profile of SYSU M49105^T contained two unidentified phosphoglycolipids, nine unidentified glycolipids, and five unidentified polar lipids. SYSU M42101^T had one unidentified phosphoglycolipid, nine unidentified glycolipids, one unidentified aminophospholipid and four unidentified polar lipids. The major fatty acids of strains SYSU M49105^T and SYSU M42101^T were summed feature 3 (C_16:1 ω7c and/ or C_16:1 ω6c) and C_16:0. The G + C contents of the novel isolates based on genomic DNAs were 69.6% and 67.4%, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strains SYSU M49105^T and SYSU M42101^T should be considered to represent two novel species in the genus Deinococcus, for which the names Deinococcus aestuarii sp. nov. and Deinococcus aquaedulcis sp. nov. were proposed with the type strains SYSU M49105^T (= KCTC 43258 ^T = CGMCC 1.18609 ^T) and SYSU M42101^T (= KCTC 43257 ^T = CGMCC 1.18614 ^T), respectively.

A new era of radiation resistance bacteria in bioremediation and production of bioactive compounds with therapeutic potential and other aspects: An in-perspective review

Microorganisms that survive in extreme environmental conditions are known as 'extremophiles'. Recently, extremophiles draw an impression in biotechnology/pharmaceutical researches/industries because of their novel molecules, known as 'extremolytes'. The intriguing phenomenon of microbial radiation resistance probably arose independently throughout their evolution of selective pressures (e.g. UV, X-ray, Gamma radiation etc.). Radiation produces multiple types of damage/oxidation to nucleic acids, proteins and other crucial cellular components. Most of the literature on microbial radiation resistance is based on acute γ-irradiation experiments performed in the laboratory, typically involving pure cultures isolation and their application on bioremediation/therapeutic field. There is much less information other than bioremediation and therapeutic application of such promising microbes we called as 'new era'. Here we discus origin and diversity of radiation resistance bacteria as well as selective mechanisms by which microorganisms can sustain in radiation rich environment. Potential uses of these radiations resistant microbes in the field of bioremediation, bioactive compounds and therapeutic industry. Last but not the least, which is the new aspect of radiation resistance microbes. Our review suggest that resistance to chronic radiation is not limited to rare specialized strains from extreme environments, but can occur among common microbial taxa, perhaps due to overlap molecular mechanisms of resistance to radiation and other stressors. These stress tolerance potential make them potential for radionuclides remediation, their extremolytes can be useful as anti-oxidant and anti-proliferative agents. In current scenario they can be useful in various fields from natural dye synthesis to nanoparticles production and anti-cancer treatment.

Comparative genomics of wild-type and laboratory-evolved biofilm-overproducing Deinococcus metallilatus strains

Deinococcus metallilatus MA1002 was exposed to ultraviolet radiation to generate mutants with enhanced biofilm production. Two strains (nos 5 and 6) were then selected based on their high biofilm formation, as well as their possession of higher concentrations of extracellular matrix components (eDNA, protein and saccharides) than the wild-type (WT). Genomic sequencing revealed the presence of large genome deletions in a secondary chromosome in the mutants. Expression analyses of the WT and mutant strains indicated the upregulation of genes associated with exopolysaccharide synthesis and stress response. The mutant strains showed high mortality in glucose-supplemented (TYG) medium; however, cell death and biofilm formation were not increased in mutant cells grown under acetate- or glyoxylate-added media, suggesting that metabolic toxicity during glucose metabolism induced a high rate of cell death but improved biofilm formation in mutant strains. In damaged cells, eDNAs contributed to the enhanced biofilm formation of D. metallilatus.

Deinococcus terrestris sp. nov., a gamma ray- and ultraviolet-resistant bacterium isolated from soil

Strain SDU3-2^T was isolated from a soil sample collected in Shandong Province, PR China. Cells of SDU3-2^T were spherical, Gram-stain-positive, aerobic and non-motile. Cellular growth of the strain occurred at 25-45 °C, pH 5.5-8.5 and with 0-1.5 % (w/v) of NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain SDU3-2^T was closest to the type strain Deinococcus murrayi ALT-1b^T with a similarity of 95.2 %. The draft genome was 3.49 Mbp long with 69.2 mol% G+C content. Strain SDU3-2^T exhibited high resistance to gamma radiation (D₁₀ >12 kGy) and UV (D₁₀ >900 J m^-2). The strain encoded many genes for resistance to radiation and oxidative stress, which were highly conserved with other Deinococcus species, but possessed interspecific properties. The major fatty acids of SDU3-2^T cells were C_15 : 1  ω6c, C_16 : 1  ω7c/C_16 : 1  ω6c, and C_17 : 1  ω8c, the major menaquinone was menaquinone-8, and the major polar lipids were an unidentified phosphoglycolipid, four unidentified glycolipids and an unidentified phospholipid. The average nucleotide identity and DNA-DNA hybridization results further indicated that strain SDU3-2^T represents a new species in the genus Deinococcus, for which the name Deinococcus terrestris sp. nov. is proposed. The type strain is SDU3-2^T (=CGMCC 1.17147^T=KCTC 43098^T).

Deinococcus detaillensis sp. nov., isolated from humus soil in Antarctica

A Gram-staining-positive, non-motile, coccus or short-rod-shaped bacterium, designated H1^T, was isolated from a humus soil sample in the Detaille Island of Antarctica. The 16S rRNA gene sequence result indicated that strain H1^T shared the highest 16S rRNA gene sequence identity with the type strain of Deinococcus alpinitundrae (96.2%). Growth of strain H1^T occurred at 4-25 °C, pH 6.0-8.0 and in the presence of 0-1.0% NaCl (w/v). The respiratory quinone was MK-8. The major fatty acids were C_16:0, C_17:0 cyclo and summed feature 3 (C_16:1 ω7c/C_16:1 ω6c). The polar lipids were aminoglycophospholipid, aminophospholipid, glycolipid and glycophospholipid. The cell wall peptidoglycan type was A3β. The genomic DNA G + C content was 61.3 mol%. The average nucleotide identity (ANI) between strain H1^T and the closely related Deinococcus members was below the cut-off level (95-96%) for species identification. Based on the above results, strain H1^T represents a novel species of the genus Deinococcus, for which the name Deinococcus detaillensis sp. nov. is proposed. Type strain is H1^T (= CGMCC 1.13938^T = JCM 33291^T).

Deinococcus psychrotolerans sp. nov., isolated from soil on the South Shetland Islands, Antarctica

A Gram-stain-negative, non-motile, strictly aerobic, coccus-shaped bacterium, designated S14-83^T, was isolated from a soil sample collected from the South Shetland Islands of Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain is a novel member of the genus Deinococcus, with Deinococcus alpinitundrae as its closest relative (96.1 % similarity). The DNA G+C content of the strain was 61.1 mol% and the major respiratory quinone was MK-8. Major cellular fatty acids were summed feature 3 (C_16 : 1ω7c/C_16 : 1ω6c) and C_16 : 0. As well as containing glycophospholipid, aminophospholipids and glycolipid as major polar lipids, there were also some unknown polar lipids. The diagnostic diamino acid in the cell-wall peptidoglycan was ornithine, corroborating the assignment of the strain to the genus Deinococcus. Strain S14-83^T was shown to be extremely resistant to gamma radiation (>10 kGy) and UV light (460 Jm^-2). On the basis of phylogenetic, chemotaxonomic and phenotypic data presented here, strain S14-83^T represents a novel species of the genus Deinococcus, for which the name Deinococcus psychrotolerans sp. nov. is proposed. The type strain is S14-83^T (=CCTCC AB 2015449^T= DSM 105285 ^T).

Effects of Deinococcus spp. supplement on egg quality traits in laying hens

To counter the ill effects of synthetic dyes, bacterial pigment production as an alternative is now one of the promising and emerging fields of research. This study was conducted to evaluate the applicability of Deinococcus genus on the egg quality traits in laying hens. In study I, 24 single comb White Leghorn layers were fed with various 1 wt % Deinococcus bacterial strains for 10 d. In study II, 84 brown Hendrix layers were fed with one of 4 diets containing 0, 0.2, 1, or 5 wt % Deinococcus sp. GKB-Aid 1995 powder for 12 wk. In study III, 60 White Leghorn laying hens were fed either with or without 1 wt % Deinococcus sp. GKB-Aid 1995 powder, 1 wt % Deinococcus sp. GKB-Aid 1995 granules, or 1 wt % Deinococcus sp. GKB-Aid 1995 oily granules for 10 successive d. In all of the experiments, feeding Deinococcus powder did not affect egg quality traits except for the yolk color. In particular, supplementation with all Deinococcus powder treatments changed the yolk color (P < 0.05) in study I, with the best pigmentation score obtained by D. grandis and Deinococcus sp. GKB-Aid 1995. Moreover, longer supplementation of Deinococcus sp. GKB-Aid 1995 in study II had a significant effect on feed conversion ratio. With these findings under consideration, the present study suggests that the Deinococcus species, especially Deinococcus sp. GKB-Aid 1995, can be an excellent candidate for improving egg yolk color in laying hens.

Deinococcus koreensis sp. nov., a gamma radiation-resistant bacterium isolated from river water

A gamma radiation-resistant, Gram-stain-negative, rod-shaped bacterial strain, designated SJW1-2^T, was isolated from freshwater samples collected from the Seomjin River, Republic of Korea. The 16S rRNA gene sequence analyses showed that strain SJW1-2^T was most closely related to Deinococcus metalli 1PNM-19^T (94.3 % sequence similarity) and formed a robust phylogenetic clade with other species of the genus Deinococcus. The optimum growth pH and temperature for the isolate were pH 7.0-7.5 and 25 °C, respectively. Strain SJW1-2^T exhibited high resistance to gamma radiation. The predominant respiratory quinone was MK-8. The polar lipid profile consisted of different unidentified glycolipids, two unidentified lipids, two unidentified phospholipids and an unidentified phosphoglycolipid. The major peptidoglycan amino acids were alanine, d-glutamic acid, glycine and l-ornithine. The predominant fatty acids (>10 %) were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) (25.2 %) and C16 : 0 (21.2 %), and the DNA G+C content was 69.5 mol%. On the basis of phenotypic, genotypic and phylogenetic analyses, strain SJW1-2^T (=KACC 19332^T=NBRC 112908^T) represents a novel species of the genus Deinococcus, for which the name Deinococcus koreensis sp. nov. is proposed.

Deinococcus rufus sp. nov., isolated from soil near an iron factory

A Gram-stain-negative, non-motile, rod-shaped, red-pigmented strain, designated W37^T, was isolated from soil near an iron factory in Busan (Republic of Korea). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain W37^T was most closely related to Deinococcus yunweiensis YIM 007^T (98.3 %) and Deinococcus radioresistens 8A^T (96.3 %). The DNA-DNA relatedness between strain W37^T and D. yunweiensis YIM 007^T was 50.5 %. The predominant respiratory quinone was MK-8. The major polar lipids were an unidentified phosphoglycolipid, an unidentified aminophospholipid, four unidentified glycolipids, two unidentified phospholipids and an unidentified lipid. The major fatty acids (>5 %) of strain W37^T were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0, C17 : 1ω8c and iso-C17 : 1ω9c. The DNA G+C content was 69.0 mol%. Moreover, the chemo-physical characteristics of strain W37^T clearly differed from those of related species, including ranges of growth temperature and pH, positive activity for 4-hydroxybenzoate and negative activity for cystine arylamidase. Phenotypic, chemotaxonomic and genotypic analyses indicated that strain W37^T represents a novel species of the genus Deinococcus, for which the name Deinococcus rufus sp. nov., is proposed. The type strain is W37^T (=KCTC 33913^T=CCTCC AB 2017081^T).

Deinococcus aluminii sp. nov., isolated from an automobile air conditioning system

A Gram-stain-positive and pale pink-pigmented bacterial strain, designated ID0501^T, was isolated from an automobile evaporator core collected in the Republic of Korea. The cells were aerobic and coccoidal. The strain grew at 15-40 ˚C (optimum, 37 ˚C), at pH 6.0-7.0 (optimum, pH 6.5), and in the presence of 0-1.5 % (w/v) NaCl. Phylogenetically, the strain was related to members of the genus Deinococcus and showed the highest sequence similarity, of 96.9 %, with Deinococcus metallilatus MA1002^T. The major fatty acids of the strain were iso-C_17 : 0, iso-C_15 : 0 and iso-C_13 : 0. The predominant respiratory quinone was MK-8. The polar lipids profile revealed the presence of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, unidentified phospholipids, an unidentified aminolipid and unidentified glycolipids. The DNA G+C content of the strain was 68.3 mol%. On the basis of phenotypic, genotypic and chemotaxonomic data, strain ID0501^T represents a novel species of the genus Deinococcus, for which the name Deinococcusaluminii sp. nov. (=KACC 19286^T=NBRC 112889^T) is proposed.

Deinococcus multiflagellatus sp. nov., isolated from a car air-conditioning system

A gamma radiation-resistant and pink-to-red pigmented bacterial strain, designated ID1504^T, was isolated from a car air-conditioning system sampled in Korea. The cells were observed to be Gram-stain negative, aerobic, motile with peritrichous flagella and short rod-shaped. Phylogenetically, the strain groups with the members of the genus Deinococcus and exhibits high 16S rRNA gene sequence similarities with Deinococcus arenae SA1^T (94.0%), Deinococcus actinosclerus BM2^T (93.9%) and Deinococcus soli N5^T (93.5%). The predominant fatty acids were identified as C_17:0, C_16:0, summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and iso-C_17:0. The major respiratory quinone was identified as MK-8. The polar lipids were found to be comprised of unidentified phospholipids, unidentified glycolipids, an unidentified aminophospholipid and an unidentified lipid. The DNA G+C content of the strain was determined to be 68.3 mol%. On the basis of the phenotypic, genotypic and chemotaxonomic characteristics, strain ID1504^T should be classified in a novel species in the genus Deinococcus, for which the name Deinococcus multiflagellatus sp. nov. (= KACC 19287^T = NBRC 112888^T) is proposed.

Description of Deinococcus populi sp. nov. from the trunk surface of a Japanese aspen tree

A bacterial strain designated PtRA-8^T was isolated from the trunk surface of a Japanese aspen tree (Populus tremula var. sieboldii). Cells of strain PtRA-8^T were aerobic, non-motile, non-spore forming, Gram-stain-negative rods, 1.0‒2.0 µm in width and 3.0‒10.0 µm in length. The pH range for growth was between 5.5 and 7.5, with an optimum at 6.5. The temperature range for growth was between 10 and 37 °C, with an optimum at around 25‒30 °C. Strain PtRA-8^T was highly resistant to UV irradiation, similar to its Deinococcus relatives. The respiratory quinone was menaquinone MK-8. The major cellular fatty acids (> 10% of the total fatty acid content) were iso-C_15:0 (17.8%), C_16:0 (15.0%), iso-C_17:0 (10.4%), and iso-C_17:1 ω9c/C_16:010-methyl (22.2%). The polar lipids consisted of four unidentified glycolipids, two unidentified aminolipids, two unidentified phospholipids, and three unidentified polar lipids. The peptidoglycan was A3β-type containing glutamic acid, glycine, alanine, and ornithine. The DNA G + C content of strain PtRA-8^T was 68.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain PtRA-8^T was closely related to "Deinococcus radioresistens" 8A^T (97.4%), Deinococcus metalli DSM 27521^T (95.7%), and Deinococcus yunweiensis YIM 007^T (94.5%). The DNA-DNA hybridization experiments between strain PtRA-8^T and its relatives yielded relatedness values below 70%. Based on the polyphasic evidence, we concluded that strain PtRA-8^T represents a novel species within the genus Deinococcus, for which the name Deinococcus populi is proposed. The type strain of D. populi is PtRA-8^T (= DSM 29820^T= NBRC 110763^T; DPD TaxonNumber TA00271).

Deinococcus planocerae sp. nov., isolated from a marine flatworm

A Gram-positive, non-motile and coccoid strain, designated XY-FW106^T, was isolated from a marine flatworm identified to be Planocera sp. The 16S rRNA gene sequence of this pink organism was consistent with membership of the genus Deinococcus, with high sequence similarity to Deinococcus aetherius ST0316^T (94.7%). The optimum growth temperature range of the strain XY-FW106^T was found to be 25-30 °C and optimum growth occurs at pH 7.2-7.4 without NaCl. The strain XY-FW106^T was found to contain unidentified glycolipids, unidentified phosphoglycolipids, unidentified phospholipids and unidentified lipids, which differed from those of closely related species. Menaquinone MK-8 was identified as the major respiratory quinone and the predominant cellular fatty acids were found to be Summed Feature 3 (C_16:1 ω7c/C_16:1 ω6c), C_16:0, iso-C_15:0, and Summed Feature 8 (C_18:1 ω7c/C_18:1 ω6c). The DNA G+C content was determined to be 70.2 mol%. The biochemical and chemotaxonomic data together suggest that the strain represents a new species for which the name Deinococcus planocerae sp. nov. is proposed. The type strain is XY-FW106^T (=MCCC 1K01499^T=KCTC 33809^T).

Deinococcus saudiensis sp. nov., isolated from desert

Two gamma- and UV-radiation-resistant, pink-coloured bacterial strains, designated YIM F302T and YIM F235, were isolated from the desert of Yanbu' al Bahr located in west of Saudi Arabia. Taxonomic positions of the two isolates were investigated by polyphasic taxonomic approaches. Cells of the two strains were Gram-stain-negative, aerobic and rod-shaped. They were able to grow at 15-45 °C and pH 6.0-8.0 and had a NaCl tolerance limit of 1 % (w/v). Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains YIM F302T and YIM F235 represent members of the genus Deinococcus, sharing highest sequence similarities of 98.3 and 98.4 %, respectively, with Deinococcus grandis DSM 3963T. The strains were found to contain MK-8 as the respiratory menaquinone. Major fatty acids (>10 %) of the two strains were C15 : 1ω6c, C16 : 0 and C16 : 1ω7c. DNA-DNA hybridization values of the two isolates against the closely related type strains were significantly below the 70 % limit for species delineation. Genomic DNA G+C contents of strains YIM F302T and YIM F235 were 69.3 and 69.0 mol%, respectively. Based on the phenotypic and genotypic characteristics recorded, it is determined that the two isolates represent a novel species of the genus Deinococcus, for which the name Deinococcus saudiensis sp. nov. is proposed. The type strain is YIM F302T (=CGMCC 1.15089T=DSM 29933T).

Description of Deinococcus oregonensis sp. nov., from biological soil crusts in the Southwestern arid lands of the United States of America

Biological soil crusts are distinct habitats, harbor unique prokaryotic diversity and gave an impetus to isolate novel species. In the present study, a pink-pigmented bacterium, (OR316-6^T), was isolated from biological soil crusts using oligotrophic BG11-PGY medium. Strain OR316-6^T was Gram-positive, short rods, non-motile and non-spore forming. Cells were positive for catalase, oxidase and β-galactosidase and negative for most of the enzymatic activities. The major fatty acids present were C_16:0, C_17:0, and C_16:1ω7c and contained MK-8 and MK-10 as the predominant menaquinones. The cell wall peptidoglycan was of A3β variant with L-ornithine as the diamino acid. Based on the above characteristics, strain OR316-6^T was assigned to the genus Deinococcus. The phylogenetic analysis indicated that strain OR316-6^T was closely related to D. aquatilis DSM 23025^T with a 16S rRNA gene similarity of 99.3 % and clustered with a bootstrap value of 100 %. DNA-DNA similarity between strain OR316-6^T and D. aquatilis DSM 23025^T was 37.0 % indicating that strain OR316-6^T was a novel species. Further, DNA fingerprinting of stains OR316-6^T and D. aquatilis DSM 23035^T demonstrated that both strains were related to each other with a similarity coefficient of only 0.32 and supported the species status to strain OR316-6^T. In addition, phenotypic characteristics distinguished strain OR316-6^T from D. aquatilis DSM 23025^T. Based on the cumulative differences, strain OR316-16^T exhibited with its closely related species, it was identified as a novel species and proposed the name Deinococcus oregonensis sp. nov. The type strain is D. oregonensis sp. nov. (OR316-6^T = JCM 13503^T = DSM 17762^T).

EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils

The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils.

Characterization and safety evaluation of a Deinococcus member as feed additive for hens

As previous studies mainly focus on understanding the mechanisms of radioresistance in Deinococcus bacteria, the present study aimed at characterizing and verifying the safety use of the GKB-Aid 1995 strain, a member of the radiation-resistant bacterial genus Deinococcus, as an ingredient in feed supplements. Using Vitek 2 system and 16S rRNA gene sequencing, GKB-Aid 1995 most resembles Deinococcus grandis. The Ames test, in vitro chromosomal test, in vivo micronucleus test and acute toxicity test were performed subsequently for its safety evaluation. As there is a possibility that the pigment of GKB-Aid 1995 can pass from feed to eggs intended for human consumption, an acute toxicity test was also carried out in pigmented egg yolk. The results confirmed that GKB-Aid 1995 was non-genotoxic in three genotoxicity experiments, and the LD50 of GKB-Aid 1995 and the pigmented egg yolk in ICR mice was greater than 10 and 12 g kg(-1) body weight, respectively. Overall, these data indicate that GKB-Aid 1995 is a non-toxic substance with no genotoxicity and is therefore safe to be used as a feed supplement or feed additive. This study suggests there is potential in developing GKB-Aid 1995 as an animal feed additive intended to enhance yolk coloration to meet the demand of consumers.

Deinococcus metalli sp. nov., isolated from an abandoned lead-zinc mine

An aerobic, non-motile and Gram-staining-positive bacterial strain (1PNM-19T) was isolated from a lead-zinc ore in an abandoned mine and was investigated in a taxonomic study using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 1PNM-19T was affiliated to the genus Deinococcus and most closely related to Deinococcus aquatilis DSM 23025T and Deinococcus ficus DSM 19119T. The major respiratory quinone was determined to be menaquinone 8 (MK-8) and the major fatty acids contained summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. A complex polar lipid profile consisted of different unidentified glycolipids and polar lipids, two unidentified aminolipids, an unidentified phosphoglycolipid, phospholipid and aminophospholipid. The genomic DNA G+C content of strain 1PNM-19T was 71.7 ± 0.1 mol%. Based on data from this taxonomic study, strain 1PNM-19T represents a novel species of the genus Deinococcus, for which the name Deinococcus metalli sp. nov. is proposed. The type strain is 1PNM-19T ( = GIMCC 1.654T = CCTCC AB 2014198T = DSM 27521T).

Deinococcus antarcticus sp. nov., isolated from soil

A pink-pigmented, non-motile, coccoid bacterial strain, designated G3-6-20T, was isolated from a soil sample collected in the Grove Mountains, East Antarctica. This strain was resistant to UV irradiation (810 J m−2) and slightly more sensitive to desiccation as compared with Deinococcus radiodurans . Phylogenetic analyses based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus . Highest sequence similarities were with Deinococcus ficus CC-FR2-10T (93.5 %), Deinococcus xinjiangensis X-82T (92.8 %), Deinococcus indicus Wt/1aT (92.5 %), Deinococcus daejeonensis MJ27T (92.3 %), Deinococcus wulumuqiensis R-12T (92.3 %), Deinococcus aquaticus PB314T (92.2 %) and Deinococcus radiodurans DSM 20539T (92.2 %). Major fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), anteiso-C15 : 0 and C16 : 0. The G+C content of the genomic DNA of strain G3-6-20T was 63.1 mol%. Menaquinone 8 (MK-8) was the predominant respiratory quinone. Based on its phylogenetic position, and chemotaxonomic and phenotypic characteristics, strain G3-6-20T represents a novel species of the genus Deinococcus , for which the name Deinococcus antarcticus sp. nov. is proposed. The type strain is G3-6-20T ( = DSM 27864T = CCTCC AB 2013263T).

Deinococcus citri sp. nov., isolated from citrus leaf canker lesions

A Gram-stain-positive, strictly aerobic, non-motile, coccoid bacterium, designated NCCP-154(T), was isolated from citrus leaf canker lesions and was subjected to a polyphasic taxonomic study. Strain NCCP-154(T) grew at 10-37 °C (optimum 30 °C) and at pH 7.0-8.0 (optimum pH 7.0). The novel strain exhibited tolerance of UV irradiation (>1000 J m(-2)). Based on 16S rRNA gene sequence analysis, strain NCCP-154(T) showed the highest similarity to Deinococcus gobiensis CGMCC 1.7299(T) (98.8 %), and less than 94 % similarity to other closely related taxa. The chemotaxonomic data [major menaquinone, MK-8; cell-wall peptidoglycan type, A3β (Orn-Gly2); major fatty acids, summed feature 3 (C16 : 1ω7c/iso-C15 : 0 2-OH; 35.3 %) followed by C16 : 0 (12.7 %), iso-C17 : 1ω9c (9.2 %), C17 : 1ω8c (7.4 %) and iso-C17 : 0 (6.9 %); major polar lipids made up of several unidentified phosphoglycolipids and glycolipids and an aminophospholipid, and mannose as the predominant whole-cell sugar] also supported the affiliation of strain NCCP-154(T) to the genus Deinococcus. The level of DNA-DNA relatedness between strain NCCP-154(T) and D. gobiensis JCM 16679(T) was 63.3±3.7 %. The DNA G+C content of strain NCCP-154(T) was 70.0 mol%. Based on the phylogenetic analyses, DNA-DNA hybridization and physiological and biochemical characteristics, strain NCCP-154(T) can be differentiated from species with validly published names. Therefore, it represents a novel species of the genus Deinococcus. The name Deinococcus citri sp. nov. is proposed, with the type strain NCCP-154(T) ( = JCM 19024(T) = DSM 24791(T) = KCTC 13793(T)).

Radiation-resistant extremophiles and their potential in biotechnology and therapeutics

Extremophiles are organisms able to thrive in extreme environmental conditions. Microorganisms with the ability to survive high doses of radiation are known as radioresistant or radiation-resistant extremophiles. Excessive or intense exposure to radiation (i.e., gamma rays, X-rays, and particularly UV radiation) can induce a variety of mutagenic and cytotoxic DNA lesions, which can lead to different forms of cancer. However, some populations of microorganisms thrive under different types of radiation due to defensive mechanisms provided by primary and secondary metabolic products, i.e., extremolytes and extremozymes. Extremolytes (including scytonemin, mycosporine-like amino acids, shinorine, porphyra-334, palythine, biopterin, and phlorotannin, among others) are able to absorb a wide spectrum of radiation while protecting the organism's DNA from being damaged. The possible commercial applications of extremolytes include anticancer drugs, antioxidants, cell-cycle-blocking agents, and sunscreens, among others. This article aims to review the strategies by which microorganisms thrive in extreme radiation environments and discuss their potential uses in biotechnology and the therapeutic industry. The major challenges that lie ahead are also discussed.

Characterization of Deinococcus sahariens sp. nov., a radiation-resistant bacterium isolated from a Saharan hot spring

An ultraviolet-radiation-resistant, Gram-positive, orange-pigmented, thermophilic and strictly aerobic cocci was isolated from Saharan water hot spring in Tunisia. The newly isolated bacterium, designated HAN-23(T), was identified based on polyphasic taxonomy including genotypic, phenotypic and chemotaxonomic characterization. Phylogenetic analysis based on 16S rRNA gene sequences placed this strain within Deinococcus genus. However, strain HAN-23(T) is different from recognized species of the genus Deinococcus, showing less than 94.0% similarity values to its closest relatives. The predominant cellular fatty acids determined by gas chromatography were iso-C(15:0), iso-C(17:0) and iso C(17:1) ω9c. The major respiratory quinone was MK-8. The DNA G + C content was 66.9 mol%. DNA-DNA hybridization measurements revealed low DNA relatedness (6%) between the novel isolate and its closest neighbor, the type strain Deinococcus geothermalis DSM 11300. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain HAN-23(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus sahariens sp. nov. is proposed, the type strain being HAN-23(T) (=DSM 18496(T); LMG 23756(T)).

Deinococcus depolymerans sp. nov., a gamma- and UV-radiation-resistant bacterium, isolated from a naturally radioactive site

Four gamma- and UV-radiation-resistant bacterial strains, designated TDMA-24T, TDMA-24-2, TDMA-24-3 and TDMA-24-4, were isolated from a fresh-water sample collected at Misasa, Tottori, Japan. Cells of these strains were Gram-reaction-positive, non-motile, non-spore-forming, rod-shaped and formed red colonies. The genomic DNA G+C contents ranged from 70.5 to 70.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel isolates belong to the genus Deinococcus, the highest sequence similarities being with Deinococcus aquaticus PB314T (98 %) and Deinococcus caeni Ho-08T (97 %). The polar lipid profile of strain TDMA-24T comprised three unidentified phosphoglycolipids, five unidentified glycolipids and seven unidentified polar lipids. MK-8 was the predominant respiratory quinone. Major fatty acids were iso-C15 : 0, C15 : 1ω6c, C15 : 0, C16 : 0 and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). On the basis of their phylogenetic positions and chemotaxonomic and phenotypic characteristics, the novel isolates represent a novel species of the genus Deinococcus, for which the name Deinococcus depolymerans sp. nov. is proposed. The type strain is TDMA-24T ( = JCM 14369T  = NBRC 102115T  = CCUG 53609T).

Deinobacterium chartae gen. nov., sp. nov., an extremely radiation-resistant, biofilm-forming bacterium isolated from a Finnish paper mill

A rod-shaped, non-spore-forming, non-motile, aerobic, oxidase and catalase-positive and radiation-resistant bacterium (designated strain K4.1(T)) was isolated from biofilm collected from a Finnish paper mill. The bacterium grew as pale pink colonies on oligotrophic medium at 12 to 50 °C (optimum 37 to 45 °C) and at pH 6 to 10.3. The DNA G+C content of the strain was 66.8 l%. According to 16S rRNA gene sequence analysis, strain K4.1(T) was distantly related to the genus Deinococcus, sharing highest similarity with Deinococcus pimensis (90.0  %). In the phylogenetic tree, strain K4.1(T) formed a separate branch in the vicinity of the genus Deinococcus. The peptidoglycan type was A3β with L-Orn-Gly-Gly and the quinone system was determined to be MK-8. The polar lipid profile of strain K4.1(T) differed markedly from that of the genus Deinococcus. The predominant lipid of strain K4.1(T) was an unknown aminophospholipid and it did not contain the unknown phosphoglycolipid predominant in the polar lipid profiles of deinococci analysed to date. Two of the predominant fatty acids of the strain, 15 : 0 anteiso and 17 : 0 anteiso, were lacking or present in small amounts in species of the genus Deinococcus. Phylogenetic distinctness and significant differences in the polar lipid and fatty acid profiles suggest classification of strain K4.1(T) as a novel genus and species in the family Deinococcaceae, for which we propose the name Deinobacterium chartae gen. nov., sp. nov. The type strain is K4.1(T) (=DSM 21458(T) =HAMBI 2721(T)).

Deinococcus gobiensis sp. nov., an extremely radiation-resistant bacterium

A Gram-positive, non-motile, spherical, red-pigmented and facultatively anaerobic bacterium, designated strain I-0(T), was isolated from a sand sample of the Gobi desert in Xinjiang Autonomous Region, China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that this isolate represents a novel member of the genus Deinococcus, with low sequence similarities (<94 %) to recognized Deinococcus species. The major cellular fatty acids were C(16 : 1)omega7c and C(16 : 0). Its polar lipid profile contained several unidentified glycolipids, phosphoglycolipids, phospholipids, pigments and an aminophospholipid. The peptidoglycan type was Orn-Gly(2) (A3beta) and the predominant respiratory quinone was MK-8. The DNA G+C content was 65.4 mol%. DNA-DNA relatedness between strain I-0(T) and Deinococcus radiodurans ACCC 10492(T) was 37 %. The strain was shown to be extremely resistant to gamma radiation (>15 kGy) and UV light (>600 J m(-2)). On the basis of the phylogenetic, chemotaxonomic and phenotypic data presented, strain I-0(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus gobiensis sp. nov. is proposed. The type strain is I-0(T) (=DSM 21396(T) =CGMCC 1.7299(T)).

Iso-superoxide dismutase in Deinococcus grandis, a UV resistant bacterium

Deinococcus grandis possesses two types of superoxide dismutase (SOD, E. C. 1.15.1.1.) that show distinct electrophoretic behavior, one that migrates slowly and the other that migrates rapidly (SOD-1 and SOD-2, respectively). In this study, SOD-1 was uniformly and abundantly detected, regardless of growth phase, whereas SOD-2 was not detected during early growth, but was detectable from the exponential growth phase. In addition, a substantial increase in SOD-2 was observed in cells that were treated with potassium superoxide or UV, which suggests that SOD-2 is an inducible protein produced in response to stressful environments. Insensitivity of SOD-1 to both H(2)O(2) and cyanide treatment suggests that SOD-1 is MnSOD. However, SOD-2 would be FeSOD, since it lost activity in response to H(2)O(2) treatment, but not to cyanide. Localization studies of D. grandis iso-SODs in sucrose-shocked cells suggest that SOD-1 is a membrane-associated enzyme, whereas SOD-2 is a cytosolic enzyme. In conclusion, SOD-1 seems to be an essential constitutive enzyme for viability and SOD-2 appears to be an inducible enzyme that is probably critical for survival upon UV irradiation and oxidative stress.

Deinococcus aquatilis sp. nov., isolated from water

A pale-pink strain (CCUG 53370(T)) from water was investigated by a polyphasic taxonomic approach. The cells stained Gram-positive and were rod-shaped and non-spore-forming. Analyses using the 16S rRNA gene sequence of the isolate showed that the organism belongs to the genus Deinococcus, with the highest sequence similarities to the type strains of Deinococcus ficus (94.4 %), Deinococcus navajonensis (94.3 %) and Deinococcus mumbaiensis (94.3 %). Chemotaxonomic data revealed that CCUG 53370(T) contains exclusively menaquinone MK-8 as the respiratory quinone and a complex polar lipid profile consisting of different unidentified glycolipids and polar lipids, two unknown phospholipids and three unknown phosphoglycolipids. As in other deinococci, one of these phosphoglycolipids was predominant in the profile, and it was identified in Deinococcus radiodurans as 2'-O-(1,2-diacyl-sn-glycero-3-phospho)-3'-O-(alpha-galactosyl)-N-D-glyceroyl alkylamine. Predominant fatty acids were C(16 : 1)omega7c, C(17 : 1)omega8c and C(17 : 1)omega9c. Biochemical and chemotaxonomic properties demonstrate that strain CCUG 53370(T) represents a novel species, for which the name Deinococcus aquatilis sp. nov. is proposed. The type strain is CCUG 53370(T) (=CCM 7524(T)).

Description of four novel psychrophilic, ionizing radiation-sensitive Deinococcus species from alpine environments

Five psychrophilic bacterial strains were isolated from soil samples collected above the treeline of alpine environments. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these organisms represent four novel species of the genus Deinococcus; levels of sequence similarity to the type strains of recognized Deinococcus species were in the range 89.3-94.7 %. Strains PO-04-20-132T, PO-04-20-144, PO-04-19-125T, ME-04-01-32T and ME-04-04-52T grew aerobically, with optimum growth at 10 degrees C and at pH 6-9. The major respiratory menaquinone was MK-8. The fatty acid profiles of strains PO-04-20-132T, PO-04-20-144, PO-04-19-125T and ME-04-01-32T were dominated by 16 : 1omega7c, 17 : 0 iso and 15 : 1omega6c, whereas 16 : 1omega7c, 17 : 0 cyclo and 16 : 0 predominated in strain ME-04-04-52T. The DNA G+C contents of strains PO-04-20-132T, PO-04-19-125T, ME-04-01-32T and ME-04-04-52T were 63.2, 63.1, 65.9 and 62.6 mol%, respectively. Strains PO-04-20-132T, PO-04-19-125T, ME-04-01-32T and ME-04-04-52T had gamma radiation D10 (dose required to reduce the bacterial population by 10-fold) values of < or =4 kGy. These four strains showed sensitivity to UV radiation and extended desiccation as compared with Deinococcus radiodurans. On the basis of the phylogenetic analyses, and chemotaxonomic and phenotypic data, it is proposed that strains PO-04-20-132T (=LMG 24019T=NRRL B-41950T; Deinococcus radiomollis sp. nov.), PO-04-19-125T (=LMG 24282T=NRRL B-41949T; Deinococcus claudionis sp. nov.), ME-04-01-32T (=LMG 24022T=NRRL B-41947T; Deinococcus altitudinis sp. nov.) and ME-04-04-52T (=LMG 24283T=NRRL B-41948T; Deinococcus alpinitundrae sp. nov.) represent the type strains of four novel species of the genus Deinococcus.

Deinococcus peraridilitoris sp. nov., isolated from a coastal desert

Three ionizing-radiation-resistant bacterial strains (designated KR-196, KR-198 and KR-200(T)) were isolated from a sample of arid soil collected from a coastal desert in Chile. The soil sample was irradiated before serial dilution plating was performed using one-tenth-strength plate count agar. Phylogenetic analysis of the 16S rRNA gene sequences showed these organisms to represent a novel species of the genus Deinococcus, having sequence similarities of 87.3-90.8 % with respect to recognized Deinococcus species. Strains KR-196, KR-198 and KR-200(T) were aerobic and showed optimum growth at 30 degrees C and pH 6.5-8.0. The major respiratory menaquinone was MK-8. The predominant fatty acids in these strains were 16 : 1 omega 7c, 16 : 0, 15 : 1 omega 6c, 17 : 0 and 18 : 0. The DNA G+C content of strain KR-200(T) was 63.9 mol%. Strains KR-196, KR-198 and KR-200(T) were found to be resistant to >10 kGy gamma radiation. On the basis of the phylogenetic, chemotaxonomic and phenotypic data, strain KR-200(T) represents a novel species of the genus Deinococcus, for which the name Deinococcus peraridilitoris sp. nov. is proposed. The type strain is KR-200(T) (=LMG 22246(T)=CIP 109416(T)).