| promoter probe and shuttle plasmids for deinococcus radiodurans. | two improved deinococcus radiodurans-escherichia coli shuttle vectors have been constructed. pi3 is a 16-kb plasmid that confers chloramphenicol resistance in d. radiodurans (cmr, cat) and ampicillin resistance in e. coli (apr) and contains a multiple cloning site that does not interrupt sequences necessary for replication or drug resistance in either host. pi304 is a promoter-probe plasmid that is similar to pi3, but lacks the d. radiodurans promoting sequence for the cat gene, while retaining ... | 1992 | 1461940 |
| dna polymorphisms in new isolates of 'deinococcus radiopugnans'. | nineteen new deinococcus isolates from soil, 18 of which were from samples immediately adjacent to a lake in nottingham, uk, were characterized by conventional criteria, and found to be identical to each other and to conform most closely to the species d. radiopugnans. however, we detected three different restriction enzyme activities in three different isolates. because of this suggestion of heterogeneity, we examined the isolates for restriction fragment length polymorphisms (rflps). rflp anal ... | 1991 | 1683397 |
| atomic force microscopy of a hydrated bacterial surface protein. | the protein surface layer of the bacterium deinococcus radiodurans (hpi layer) was examined with an atomic force microscope (afm). the measurements on the air-dried, but still hydrated layer were performed in the attractive imaging mode in which the forces between tip and sample are much smaller than in afm in the repulsive mode or in scanning tunnelling microscopy (stm). the results are compared with stm and transmission electron microscopy (tem) data. | 1991 | 1688334 |
| ap endonuclease and uracil dna glycosylase activities in deinococcus radiodurans. | an endonuclease specific for apurinic/apyrimidinic (ap) sites was identified and purified from extracts of deinococcus radiodurans. the enzyme is 34.5 kd, has no activity towards normal, alkylated, uracil-containing, or uv-irradiated dna, and is active in the presence of edta. the addition of up to 10 mm mg2+ or mn2+ did not affect activity, but higher concentrations were inhibitory. there is no associated exonuclease activity, either in the presence or absence of divalent cation. optimal reacti ... | 1991 | 1711152 |
| influence of repeated lyophilization on the survival of deinococcus proteolyticus, micrococcus luteus and escherichia coli. | repeated lyophilization of deinococcus proteolyticus, micrococcus luteus and escherichia coli cells results in a successive decrease of their survival. the survival curve is exponential with e. coli and m. luteus, and sigmoidal with a broad shoulder with d. proteolyticus both after repeated lyophilization and after uv- or gamma-irradiation. when cells were subjected to gamma-irradiation after a 20-fold freeze-drying, the corresponding survival curve became exponential without the shoulder. hence ... | 1991 | 1841852 |
| phosphatidylglyceroylalkylamine, a novel phosphoglycolipid precursor in deinococcus radiodurans. | we report here the structure of a previously uncharacterized phospholipid in the radiation-resistant bacterium deinococcus radiodurans. this phospholipid, designated lipid 4, was shown by chemical analysis, hf hydrolysis, and nuclear magnetic resonance spectroscopy to be phosphatidylglyceroylalkylamine. lipid 4 thus contains the unusual lipid constituents glyceric acid and alkylamines, which have previously been identified in two complex phosphoglycolipids from this organism. by [32p]phosphate p ... | 1991 | 1987140 |
| radiation resistance of microorganisms on unsterilized infusion sets. | three different methods were used for detecting and isolating microorganisms with high radiation resistance from the microbial contamination on infusion sets prior to sterilization. by all three methods, microorganisms with a radiation resistance high enough to be a critical factor in a sterilization process (d-6 value greater than or equal to 30 kgy) were found with a frequency of approximately two colony forming units (cfu) per 100 product items, even though the product items in two of the ser ... | 1991 | 2069803 |
| [polyamines in representative taxa of coryneform and other bacteria]. | the composition of polyamines is studied for the first time in representatives of the genus micrococcus and taxon "conglomeratus", strains staphylococcus aureus ccm 209, deinococcus erythromyxa ccm 706 as well as of erwinia carotovora atcc 15713 polyamines, which are not extracted by perchloric acid. considerable amounts of spermine and rarely of spermidine are revealed in cells of gram positive microorganisms, that differs them from gram negative bacteria possessing high concentrations of putre ... | 1990 | 2115965 |
| 5s rrna sequences of myxobacteria and radioresistant bacteria and implications for eubacterial evolution. | 5s rrna sequences were determined for the myxobacteria cystobacter fuscus, myxococcus coralloides, sorangium cellulosum, and nannocystis exedens and for the radioresistant bacteria deinococcus radiodurans and deinococcus radiophilus. a dendrogram was constructed by using weighted pairwise grouping based on these and all other previously known eubacterial 5s rrna sequences, and this dendrogram showed differences as well as similarities compared with results derived from 16s rrna analyses. in the ... | 1990 | 2125831 |
| manganese(ii) induces cell division and increases in superoxide dismutase and catalase activities in an aging deinococcal culture. | addition of mn(ii) at 2.5 microm or higher to stationary-phase cultures of deinococcus radiodurans ir was found to trigger at least three rounds of cell division. this mn(ii)-induced cell division (mn-cd) did not occur when the culture was in the exponential or death phase. the mn-cd effect produced daughter cells proportionally reduced in size, pigmentation, and radioresistance but proportionally increased in activity and amount of the oxygen toxicity defense enzymes superoxide dismutase and ca ... | 1990 | 2318808 |
| drdi, a unique restriction endonuclease from deinococcus radiodurans which recognizes 5'gacn6gtc3'. | | 1989 | 2542897 |
| evidence for the cloning of deinococcus radiodurans dna fragments that render escherichia coli radiation resistant. | dna from the radiation-resistant bacterium deinococcus radiodurans was isolated and used to generate a cosmid library. this cosmid library was grown in escherichia coli and radiation-resistant e. coli were isolated. following exposure to 1000 gy the radiation-resistant transformants exhibited a survival of approximately 10(-1) instead of the 10(-11) exhibited by the nontransformed e. coli. smaller fragments of dna were subcloned from the radiation-resistant e. coli; these fragments bestow simila ... | 1989 | 2687935 |
| structure of a novel glucosamine-containing phosphoglycolipid from deinococcus radiodurans. | the structure of a major novel lipid from deinococcus radiodurans has been determined to be 2'-o-(1,2-diacyl-sn-glycero-3-phospho)-3'-o-(alpha-n-acetylglucosaminyl) -n- glyceroyl alkylamine. the lipid was shown to contain a phosphatidic acid backbone by digestion with phospholipase a2 and by hydrolysis with hydrofluoric acid. using a combination of chemical and nmr spectroscopic techniques, the structure of this lipid was elucidated and compared with that of a similar phosphoglycolipid reported ... | 1989 | 2808391 |
| duplication insertion of drug resistance determinants in the radioresistant bacterium deinococcus radiodurans. | escherichia coli drug resistance plasmids were introduced into deinococcus radiodurans by cloning d. radiodurans dna into the plasmids prior to transformation. the plasmids were integrated into the chromosome of the transformants and flanked by a direct repeat of the cloned d. radiodurans segment. the plasmid and one copy of the flanking chromosomal segment constituted a unit ("amplification unit") which was found repeated in tandem at the site of chromosomal integration. up to 50 copies of the ... | 1988 | 2834326 |
| the plasmids of deinococcus spp. and the cloning and restriction mapping of the d. radiophilus plasmid pue1. | plasmids were found in strains representing all four species of the genus deinococcus viz. d. radiodurans, d. radiopugnans, d. radiophilus and d. proteolyticus but were not found in the most intensively-investigated strain of the genus, d. radiodurans r1. their sizes were calculated from electron micrographs. d. radiophilus yielded three size classes of plasmid while d. radiodurans sark, d. proteolyticus and d. radiopugnans each yielded two. attempts to cure d. radiophilus and d. radiodurans sar ... | 1985 | 2986569 |
| two new restriction endonucleases draii and draiii from deinococcus radiophilus. | in addition to recently characterized drai (1), two new type ii restriction endonucleases, draii and draiii, with novel site-specificities were isolated and purified from deinococcus radiophilus atcc 27603. draii and draiii recognize the hepta- and nonanucleotide sequences (sequence in text) the cleavage sites within both strands are indicated by arrows. the recognition sequences were established by mapping of the cleavage sites on pbr322 (draii) and fd109 rf dna (draiii). the sequence specifiti ... | 1985 | 2987827 |
| lipid composition, lipid fluidity and radioresistance of deinococcus radiodurans and two mutant strains. | the lipid composition of d. radiodurans strain r1 and of two mutant strains has been studied in relation to membrane fluidity and sensitivity to x-ray radiation. no significant difference in the unsaturation degree of fatty acids was found between parental and mutant strains. an important decrease of carbohydrate-containing lipids was observed in the radiosensitive mutant strain. we also observed a higher fluidity in both mutant strains than in the parental one. modification of membrane lipid fl ... | 1987 | 3129029 |
| nucleotide sequence analysis of the gene encoding the deinococcus radiodurans surface protein, derived amino acid sequence, and complementary protein chemical studies. | the complete nucleotide sequence of the gene encoding the surface (hexagonally packed intermediate [hpi])-layer polypeptide of deinococcus radiodurans sark was determined and found to encode a polypeptide of 1,036 amino acids. amino acid sequence analysis of about 30% of the residues revealed that the mature polypeptide consists of at least 978 amino acids. the n terminus was blocked to edman degradation. the results of proteolytic modification of the hpi layer in situ and mr estimations of the ... | 1987 | 3667529 |
| the cytotoxic and photodynamic inactivation of micro-organisms by rose bengal. | rose bengal was cytotoxic to the following bacteria at the concentrations given in parentheses (highest concentrations of dye in mol/l at which growth occurred on nutrient medium): brochothrix thermosphacta and deinococcus radiodurans (1 x 10(-6) or less); streptococcus, micrococcus, staphylococcus, bacillus, arthrobacter and kurthia spp. (1 x 10(-5)-1 x 10(-4], and pseudomonas spp. and enterobacteriaceae (5 x 10(-3)-1 x 10(-2) or greater). these organisms were killed rapidly when suspended in i ... | 1985 | 3997691 |
| molecular cloning, expression, and characterization of the gene for the surface (hpi)-layer protein of deinococcus radiodurans in escherichia coli. | the hpi protein of deinococcus radiodurans belongs to the class of surface layer proteins which form crystalline two-dimensional arrays on bacterial cell envelopes. we have cloned and expressed the gene for this protein of mr about 100,000 by using plasmid puc8 in escherichia coli. as judged by immunoreaction with monospecific antibodies, apparent mr, and limited proteolysis, a single clone contained the gene encoding the complete polypeptide on an 8.9-kilobase (kb) insert. the insert was reduce ... | 1986 | 3528123 |
| deinococcus radiodurans uv endonuclease beta dna incisions do not generate photoreversible thymine residues. | the ability of uv endonuclease beta of deinococcus radiodurans to act as a pyrimidine dimer dna glycosylase was investigated. cell-free extracts of d. radiodurans exhibiting uv endonuclease beta activity failed to generate incisions in irradiated dna that liberated free-thymine residues upon photoreversal with 254-nm light. this is in marked contrast to the pyrimidine dimer uv glycosylase of micrococcus luteus that does liberate such residues. the result suggests that uv endonuclease beta incise ... | 1988 | 3357488 |
| scanning tunnelling microscopy of biomacromolecules. | when imaging biomacromolecules with a stm, coating of specimens with a conductive layer is a convenient preparation method which provides a good rate of success. utilizing evaporated platinum/carbon as a coating film we have investigated two biomacromolecules of very different appearance. the first of these is the hpi-layer, a natural two-dimensional protein crystal with a period of 18 nm, which is found on the surface of the bacterium deinococcus radiodurans. the second specimen is type iv coll ... | 1988 | 3254999 |
| isolation of a dna-binding protein from deinococcus radiodurans having an affinity for a z-form polynucleotide. | a protein which preferentially binds z-form duplex dna has been purified from the cells of deinococcus radiodurans. the molecular weight of the protein was estimated to be approximately 68,000 by gel filtration and sds-polyacrylamide gel electrophoresis. amino acid analysis of the protein indicates that it is not so basic since it contains a lower mole percent of lysine and higher mole percent of aspartic acid than those in histone-like dna binding protein ii (hu) of escherichia coli. the first ... | 1988 | 3065334 |
| dna double-strand breakage and removal of cross-links in deinococcus radiodurans. | mitomycin c-sensitive mutants of deinococcus radiodurans were isolated which were either resistant to or only moderately sensitive to far uv (254 nm) or gamma rays. they were also sensitive to irradiation at 365 nm in the presence of 4,5',8-trimethylpsoralen. they were classified into seven complementary groups (mtca through mtcg) by transformation experiments. interstrand cross-links in the dna duplex induced by mitomycin c were removed in the cells of two mutants (mtcd and mtce) as in the wild ... | 1983 | 6411683 |
| isolation and properties of strains of micrococcus (deinococcus) radiodurans unable to excise ultraviolet light-induced pyrimidine dimers from dna: evidence for two excision pathways. | a mutant of deinococcus (formerly micrococcus) radiodurans (strain 302, mutant in mtca) sensitive to both the lethal effect of mitomycin c and the mutagenic effect of simple alkylating agents, but having wild-type resistance to uv light, was treated with the mutagen n-methyl-n'-nitro-n-nitrosoguanidine in an attempt to isolate strains deficient in the ability to excise uv-induced pyrimidine dimers. three strains were isolated that were uv-sensitive, but had wild-type resistance to the lethal eff ... | 1983 | 6415229 |
| cloning of the dna repair genes mtca, mtcb, uvsc, uvsd, uvse and the leub gene from deinococcus radiodurans. | a gene library from deinococcus radiodurans has been constructed in the cosmid pjbfh. a 51.5-kb hybrid cosmid, pue40, that transduced escherichia coli hb101 from leucine dependence to independence was selected, and a 6.9-kb fragment which carried the leub gene from d. radiodurans was subcloned into the ecori site of pat153. the dna repair genes mtca, mtcb, uvsc, uvsd and uvse, which code for two d. radiodurans uv endonucleases were identified by transforming appropriate repair-deficient mutants ... | 1985 | 2989093 |
| the action of free radicals on deinococcus radiodurans carotenoids. | the possible role of carotenoids as free radical scavengers has not been completely elucidated. to gain further insight into the quenching of oh radicals by carotenoids, we used a feasible bacterial model, deinococcus radiodurans, a red pigmented bacterium. we compared the action of h2o2 which produces in vivo oh radicals by a fenton-type reaction on the parental and two mutant strains, i.e., a red pigmented and a colorless one. while the red pigmented bacteria were resistant to h2o2 action, the ... | 1989 | 2817898 |
| lack of ultraviolet mutagenesis in radiation-resistant bacteria. | ultraviolet (uv) radiation did not induce rifampicin-resistant mutants in populations of the taxonomically-related radiation-resistant bacteria deinococcus radiodurans, d. radiopugnans, d. radiophilus and d. proteolyticus, although such mutants arose spontaneously at a low frequency and at a high frequency after treatment of cultures with n-nitroso compounds. the radiation-resistant bacteria arthrobacter radiotolerans and p-30-a were also uv-immutable whereas the more radiation-sensitive pseudom ... | 1982 | 7110166 |
| shuttle plasmids constructed by the transformation of an escherichia coli cloning vector into two deinococcus radiodurans plasmids. | an escherichia coli plasmid that confers kanamycin resistance (kmr) was inserted into the large deinococcus radiodurans cryptic plasmids pue10 and pue11, yielding ps28 and ps19. the method of insertion involved both in vitro splicing and the natural transformation of d. radiodurans and yielded full-length clones in e. coli of pue10 and pue11. both ps28 and ps19 replicated and expressed kmr in e. coli and d. radiodurans. in both ps28 and ps19, d. radiodurans plasmid sequences were immediately ups ... | 1989 | 2695951 |
| deinococcus radiodurans dna increases the radiation resistance of escherichia coli. | a genomic dna library of deinococcus radiodurans dna has been prepared using the plasmid vector pbr322. the recombinant plasmid was used to transform a more radiation-sensitive organism, escherichia coli rr1. following selection of transformed organisms by their ability to grow on ampicillin, radiation-resistant organisms were selected by irradiation with 137cs gamma radiation. increased radiation resistance correlates with the presence of a 3-kb fragment of dna in these cells which is derived f ... | 1989 | 2687934 |
| pcr primers and probes for the 16s rrna gene of most species of pathogenic bacteria, including bacteria found in cerebrospinal fluid. | a set of broad-range pcr primers for the 16s rrna gene in bacteria were tested, along with three series of oligonucleotide probes to detect the pcr product. the first series of probes is broad in range and consists of a universal bacterial probe, a gram-positive probe, a bacteroides-flavobacterium probe, and two probes for other gram-negative species. the second series was designed to detect pcr products from seven major bacterial species or groups frequently causing meningitis: neisseria mening ... | 1994 | 7512093 |
| thickness determination of biological samples with a zeta-calibrated scanning tunneling microscope. | a single-tube scanning tunneling microscope has been zeta-calibrated by using atomic steps of crystalline gold and was used for measuring the thickness of two biological samples, metal-coated as well as uncoated. the hexagonal surface layer of the bacterium deinococcus radiodurans with an open network-type structure shows thickness values that are strongly influenced by the substrate and the preparation method. in contrast, the thickness of the purple membrane of halobacterium halobium with its ... | 1990 | 2251276 |
| gene fusions with lacz by duplication insertion in the radioresistant bacterium deinococcus radiodurans. | deinococcus radiodurans is the most-studied species of a eubacterial family characterized by extreme resistance to dna damage. we have focused on developing molecular biological techniques to investigate the genetics of this organism. we report construction of lacz gene fusions by a method involving both in vitro splicing and the natural transformation of d. radiodurans. numerous fusion strains were identified by expression of beta-galactosidase. among these fusion strains, several were inducibl ... | 1990 | 2160933 |
| genetic characterization of forty ionizing radiation-sensitive strains of deinococcus radiodurans: linkage information from transformation. | natural transformation was used to help define a collection of ionizing radiation-sensitive strains of deinococcus radiodurans. three putative rec mutations were identified, as were three pol alleles. forty of the ionizing radiation-sensitive strains were placed into 16 linkage groups, and evidence obtained indicates that each linkage group consists of a cluster of mutations not more than 1,000 bp apart. in addition, a new class of d. radiodurans mutant was described that, although radioresistan ... | 1995 | 7665511 |
| salt-mediated multicell formation in deinococcus radiodurans. | the highly radiation-resistant tetracoccal bacterium deinococcus radiodurans exhibited a reversible multi-cell-form transition which depended on the nacl concentration in the medium. in response to 0.8% nacl addition into the medium, the pair/tetrad (designated 2/4) cells in a young culture grew and divided but did not separate and became 8-, 16-, and 32-cell units successively. in exponential growth phase, the cells divided in a 16/32 pattern. potassium ions were equally effective as na+ in med ... | 1991 | 2022617 |
| induction of resistance to hydrogen peroxide and radiation in deinococcus radiodurans. | though bacteria of the radiation-resistant genus deinococcus have a high resistance to the lethal and mutagenic effects of many dna-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. to investigate antioxidant enzyme responses in deinococcus spp., the catalase activity produced by these bacteria was measured and the sensitivity of these bacteria to hydrogen peroxide was tested. deinococcus spp. had higher levels of catalase and w ... | 1995 | 7720013 |
| platinum/iridium/carbon: a high-resolution shadowing material for tem, stm and sem of biological macromolecular structures. | thin pt/ir/c coating films (1.5 nm) show a fine granularity and provide a high structural resolution in the transmission electron microscope (tem) when applied to freeze-dried biological macromolecules. they keep their structure when exposed to atmospheric conditions, without the need of an additional stabilizing carbon layer, in contrast to conventional high-resolution shadowing materials such as ta/w and pt/c. however, the correct ratio of the components has turned out to be crucial. when evap ... | 1991 | 1920395 |
| reconstitution of the deinococcus radiodurans aposuperoxide dismutase. | deinococcus radiodurans, a radiation-resistant aerobe, synthesized a 43,000 mr dimeric superoxide dismutase. the holoenzyme, sp act 3300 u/mg, contained 1.5 g-atoms mn, 0.6 g-atom fe, and 0.1 g-atom zn per mole dimer. apoprotein, prepared by dialysis of the holoenzyme in denaturant plus chelator and then renatured in chelex-treated tris chloride buffer, rapidly regained superoxide dismuting activity upon incubation in 1 mm mncl2. reconstitution was dependent on mn concentration and ph. the mn-re ... | 1991 | 1897953 |
| a model for repair of radiation-induced dna double-strand breaks in the extreme radiophile deinococcus radiodurans. | the bacterium deinococcus (formerly micrococcus) radiodurans and other members of the eubacterial family deinococaceae are extremely resistant to ionizing radiation and many other agents that damage dna. stationary phase d. radiodurans exposed to 1.0-1.5 mrad gamma-irradiation sustains > 120 dna double-strand breaks (dsbs) per chromosome; these dsbs are mended over a period of hours with 100% survival and virtually no mutagenesis. this contrasts with nearly all other organisms in which just a fe ... | 1995 | 7786292 |
| evidence against enhancement of the radioresistance of escherichia coli by cloned deinococcus radiodurans dna. | deinococcus radiodurans genomic dna, introduced to escherichia coli in cloning vectors, has been reported to produce radioresistant e. coli that can be selected by gamma irradiation. in this report prior results are reassessed experimentally, and additional studies are presented. results to date suggest that the acquired radioresistance of e. coli selected by gamma irradiation does not stem from expression of stable plasmid-encoded d. radiodurans sequences, and that acquired radioresistance is n ... | 1991 | 1886991 |
| gene expression in deinococcus radiodurans. | we previously reported that the escherichia coli drug-resistance determinants apha (kanamycin-resistance) and cat (chloramphenicol-resistance) could be introduced to deinococcus radiodurans by transformation methods that produce duplication insertion. however, both determinants appeared to require dramatic chromosomal amplification for expression of resistance. additional studies described here, confirming this requirement for extensive amplification, led us to the use of promoter-probe plasmids ... | 1991 | 1849496 |
| dna-strand breaks limit survival in extreme dryness. | the inactivation of the anhydrobiotic organisms bacillus subtilis (spores) and deinococcus radiodurans during long-term exposure (up to several weeks) to extreme dryness (especially vacuum) is correlated with an increase in the number of dna-strand breaks and other dna lesions. survival finally depends on the repair of dna damages. exposure of anhydrobiotic organisms to extreme dryness (e.g. on mars or in space) for geological times will lead to so extended dna lesions that recovery is extremely ... | 1991 | 1795919 |
| plasmids in several strains of deinococcus radiodurans. | deinococcus radiodurans is known as a radioresistant bacterium. for the construction of the shuttle vector, plasmids of this bacterium were isolated and investigated. at least two new plasmids in the cells of d. radiodurans mr1, kr1 and sark were found in this experiment. however, a common plasmid among mr1, kr1 and sark strains could not be found. these plasmids would be useful for the construction of the shuttle vector for cloning radioresistant genes of this bacterium. | 1994 | 8016301 |
| partial complementation of the uv sensitivity of deinococcus radiodurans excision repair mutants by the cloned denv gene of bacteriophage t4. | deinococcus radiodurans has 2 endonucleases that incise uv-irradiated dna. uv endonuclease-alpha and uv endonuclease-beta, that are believed to functionally overlap. both endonucleases must be mutationally inactivated to yield an incisionless, markedly uv-sensitive phenotype. denv, the bacteriophage t4 gene encoding pyrimidine dimer-dna glycosylase (pd-glycosylase), was introduced and expressed via duplication insertion in d. radiodurans wild-type, and single and double uv endonuclease mutants. ... | 1991 | 1711150 |
| a highly conserved repeated chromosomal sequence in the radioresistant bacterium deinococcus radiodurans sark. | a dna fragment containing a portion of a dna damage-inducible gene from deinococcus radiodurans sark hybridized to numerous fragments of sark genomic dna because of a highly conserved repetitive chromosomal element. the element is of variable length, ranging from 150 to 192 bp, depending on the absence or presence of one or two 21-bp sequences located internally. a putative translational start site of the damage-inducible gene is within the reiterated element. the element contains dyad symmetrie ... | 1991 | 1705931 |
| analysis by pulsed-field gel electrophoresis of dna double-strand breakage and repair in deinococcus radiodurans and a radiosensitive mutant. | double-strand break (dsb) induction and rejoining after ionizing radiation was analysed in deinococcus radiodurans and a radiosensitive mutant by pulsed-field gel electrophoresis. following 2 kgy, migration of genomic dna (not restriction cleaved) from the plug into the gel was extensive, but was not observed after 90 min postirradiation recovery. by this time d. radiodurans chromosomes were intact, as demonstrated by restoration of the not i restriction cleavage pattern of 11 bands, which we fo ... | 1991 | 1680142 |
| heterozygosity and instability of amplified chromosomal insertions in the radioresistant bacterium deinococcus radiodurans. | natural transformation, duplication insertion, and plasmid transformation in deinococcus radiodurans, a bacterium that contains 4 to 10 chromosomes per cell, were studied. duplication insertions were often heterozygous, with some chromosomes containing highly amplified insertions and others containing no insertions. large amplified regions were apparently deleted by intrachromosomal recombination, generating as by-products extrachromosomal circles consisting of multiple tandem repeats of the amp ... | 1991 | 1655698 |
| fatty acids are precursors of alkylamines in deinococcus radiodurans. | deinococcus radiodurans contains novel phospholipids of which the structures of three have been previously described. these three lipids contain both fatty acids and alkylamines. both the fatty acid and alkylamine constituents were found to be composed of a mixture of species, of which c15, c16, and c17 saturated and monounsaturated alkyl chains predominated. alkylamines contained a relatively higher proportion of saturated species. progression of bacterial growth through the mid-log to stationa ... | 1992 | 1429439 |
| structure of a novel phosphoglycolipid from deinococcus radiodurans. | the chemical structure of a major phosphoglycolipid from deinococcus radiodurans has been shown to be 2'-o-(1,2-diacyl-sn-glycero-3-phospho)-3'-o-(alpha-galactosyl)-n-d-gl yceroyl alkylamine. by infrared spectroscopy, the lipid was shown to contain both carbonyl ester and amide linkages. chemical analysis demonstrated a molar ratio of fatty acid, carbohydrate, and phosphorus of 2:1:1. the lipid was shown to contain an sn-3-phosphatidic acid backbone by digestion with phospholipase a2. phosphodie ... | 1985 | 4044593 |
| identification and initial characterisation of a pyrimidine dimer uv endonuclease (uv endonuclease beta) from deinococcus radiodurans; a dna-repair enzyme that requires manganese ions. | an endonuclease that incises lightly ultraviolet-irradiated supercoiled plasmid dna was identified in cell-free extracts of deinococcus radiodurans r1 wild-type. the endonuclease was absent from strains mutant in the uvsc, uvsd or uvse genes identifying it as 'uv endonuclease beta' responsible for the initial incision step of one excision-repair pathway for the removal of pyrimidine dimers from d. radiodurans dna in vivo. the enzyme was purified free from contaminating nuclease activities and wa ... | 1985 | 3838572 |
| expression of reca in deinococcus radiodurans. | deinococcus (formerly micrococcus) radiodurans is remarkable for its extraordinary resistance to ionizing and uv irradiation and many other agents that damage dna. this organism can repair > 100 double-strand breaks per chromosome induced by ionizing radiation without lethality or mutagenesis. we have previously observed that expression of d. radiodurans reca in escherichia coli appears lethal. we now find that the reca protein of d. radiodurans is ot detectable in d. radiodurans except in the s ... | 1996 | 8550406 |
| sensitivity of deinococcus radiodurans to near-ultraviolet radiation. | although dienococcus radiodurans is notoriously resistant to far-ultraviolet radiation (fuv; 254 nm), it is highly sensitive to near-ultraviolet radiation (nuv; 300-400 nm), thus demonstrating that the mechanisms of damage (and/or recovery) by the two types of irradiation are different. this observed difference between fuv and nuv effects in d. radiodurans agrees with previous studies with escherichia coli. near-ultraviolet radiation produces dna damage which is presumed to be single-strand brea ... | 1986 | 3748048 |
| scanning probe microscopy in microbiology. | scanning probe microscopy (spm) is emerging as an important alternative to electron microscopy as a technique for analyzing submicron details on biological surfaces. microbiological specimens such as viruses, bacteriophages, and ordered bacterial surface layers and membranes have played an important role in the development of scanning tunnelling microscopy (stm) and atomic force microscopy (afm) in cellular and molecular biology. early stm studies involving metal-coated bacteriophage t4 polyhead ... | 1995 | 8574524 |
| the reca protein as a model molecule for molecular systematic studies of bacteria: comparison of trees of recas and 16s rrnas from the same species. | the evolution of the reca protein was analyzed using molecular phylogenetic techniques. phylogenetic trees of all currently available complete reca proteins were inferred using multiple maximum parsimony and distance matrix methods. comparison and analysis of the trees reveal that the inferred relationships among these proteins are highly robust. the reca trees show consistent subdivisions corresponding to many of the major bacterial groups found in trees of other molecules including the alpha, ... | 1995 | 8587109 |
| three-dimensional structure of the regular surface layer (hpi layer) of deinococcus radiodurans. | the low-resolution structure of the regular surface layer of deinococcus radiodurans has been determined from negatively stained specimens by three-dimensional electron microscopy. the layer has p6 symmetry, a lattice constant of 18 nm and a thickness of 6.5 nm. three-dimensional reconstruction was performed by a hybrid real space/fourier space approach that incorporates partial compensation of lattice distortions: the model obtained is discussed in the light of independent information about the ... | 1986 | 3701865 |
| repair of ionizing-radiation damage in the radiation resistant bacterium deinococcus radiodurans. | deinococcus radiodurans is extremely resistant to the lethal and mutagenic effects of ionizing-radiation and many other physical and chemical agents that damage dna. this resistance is known to be due to d. radiodurans' extremely proficient dna repair processes. however, little is known about the precise mechanisms employed by this organism to achieve its efficient repair. in the past two years there has been substantial progress in studies on the repair and tolerance of ionizing radiation damag ... | 1996 | 8632774 |
| sequence analysis of the l-lactate dehydrogenase-encoding gene of deinococcus radiodurans, a suitable mesophilic counterpart for thermus. | a gene encoding l-lactate dehydrogenase (ldh; ec 1.1.1.27) from deinococcus radiodurans (dr) was cloned and sequenced. the deduced amino acid (aa) sequence was compared to those of the thermus aquaticus (ta) and t. caldophilus (tc) ldh. the similarity of the g + c contents between the dr and thermus genes permits the comparison of the aa sequences of ldh without considering the difference in the g + c contents. compared to the mesophilic dr ldh, increased numbers of hydrophobic aa, together with ... | 1996 | 8654970 |
| isolation and characterisation of drai, a type ii restriction endonuclease recognising a sequence containing only a:t basepairs, and inhibition of its activity by uv irradiation of substrate dna. | a type ii restriction endonuclease, drai, isolated from deinococcus radiophilus atcc 27603 recognises the palindromic hexanucleotide sequence (formula; see text) and cleaves it, as indicated by the arrows, to produce blunt-ended fragments. the yield of enzyme is 100 to 1000 times that of the only other known type ii restriction endonuclease that recognises a sequence composed solely of a:t basepairs, the isoschizomer ahaiii (1). ultraviolet irradiation of the dna substrate at relatively low dose ... | 1983 | 6310500 |
| roles of the uvsc, uvsd, uvse, and mtca genes in the two pyrimidine dimer excision repair pathways of deinococcus radiodurans. | in deinococcus radiodurans, the genes uvsc, uvsd, uvse, and mtca are all involved in the single-strand incision of uv-irradiated dna, and mutations in at least two of them were required to produce an incisionless strain. one mutation must be in mtca and one in uvsc, uvsd, or uvse. strains carrying single mutations in any one of the genes can incise dna to the same extent as the wild-type strain. neither the presence of edta nor the absence of protein synthesis affected the incision step. strains ... | 1983 | 6313608 |
| a reappraisal of the diversity and class distribution of aspartate transcarbamoylases in gram-negative bacteria. | recently, the subunit composition of class a aspartate transcarbamoylases (atcases) in fluorescent pseudomonads has been clarified. we present evidence that distribution of this type of atcase may be more widespread than at first suspected. bacterial atcases exist in three forms: class a (molecular mass approximately 450-500 kda); class b, typified by escherichia coli atcase (approximately 300 kda); and class c, typified by bacillus subtilis atcase (approximately 100 kda). using gradient gel ele ... | 1996 | 8757751 |
| polar lipids from the radiation resistant bacterium deinococcus radiodurans: structural investigations on glucosaminyl and n-acetyl glucosaminyl lipids. | deinococcus radiodurans, although a gram-positive bacterium, has a complex cell wall with multiple layers and associates to this structural particularity, a quite unusual lipid composition for gram-positive bacteria. the conventional phospholipids (phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl glycerol...) are absent. among the nine polar lipids detected in the r1 anderson strain, three are glycolipids only one is a phospholipid, the other ones are glycophospholipids. one of the ... | 1984 | 6331531 |
| changes in cellular proteins of deinococcus radiodurans following gamma-irradiation. | in order to examine radiation-induced proteins in an extremely radioresistant bacterium, deinococcus radiodurans r1, changes in cellular proteins after gamma-irradiation were analysed by two-dimensional gel electrophoresis and silver staining. nine proteins (190, 120, 87,60, 58, 52, 46, 41 and 41 kda) were increased (or appeared) and more than 13 proteins diminished after gamma-irradiation at 6 kgy. increase of eight proteins (except for 190-kda protein) was prevented when the cells were irradia ... | 1996 | 8792456 |
| cell division in deinococcus radiodurans and a method for displaying septa. | the study of sections, freeze-cleaved, and whole-cell preparations of deinococcus radiodurans supported the contention that septa close assymmetrically and originate from discrete opposing locations on the cell surface. tetrads and the larger associations (sheets) of cells in some strains were formed by alternate and synchronized divisions in two planes. the polarity initiating the second division in cells of the sark strain, in particular, was often expressed in slower growing cells before comp ... | 1983 | 6661703 |
| sequencing of heat shock protein 70 (dnak) homologs from deinococcus proteolyticus and thermomicrobium roseum and their integration in a protein-based phylogeny of prokaryotes. | the 70-kda heat shock protein (hsp70) sequences define one of the most conserved proteins known to date. the hsp70 genes from deinococcus proteolyticus and thermomicrobium roseum, which were chosen as representatives of two of the most deeply branching divisions in the 16s rrna trees, were cloned and sequenced. hsp70 from both these species as well as thermus aquaticus contained a large insert in the n-terminal quadrant, which has been observed before as a unique characteristic of gram-negative ... | 1997 | 8990285 |
| recombination between a resident plasmid and the chromosome following irradiation of the radioresistant bacterium deinococcus radiodurans. | interplasmidic and intrachromosomal recombination in deinococcus radiodurans has been studied recently and has been found to occur at high frequency following exposure to ionizing radiation. in the current work, we document plasmid-chromosome recombination following exposure of d. radiodurans to 1.75 mrad (17.5 kgy) 60co, when the plasmid is present in the cell at the time of irradiation. recombination is assayed using both physical and allelic polymorphisms of homologous genes in the plasmid an ... | 1997 | 9099885 |
| phylogenetic diversity of the deinococci as determined by 16s ribosomal dna sequence comparison. | 16s ribosomal dna (rdna) sequences were determined for the five species of the genus deinococcus (deinococcus erythromyxa, deinococcus proteolyticus, deinococcus radiodurans, deinococcus radiophilus, and deinococcus radiopugnans) and the single species of the genus. deinobacter (deinobacter grandis). with the exception of deinococcus erythromyxa, the deinococci form a coherent phylogenetic cluster which is related to the thermus-meiothermus lineage. an analysis of the 16s rdna sequence of deinoc ... | 1997 | 9103641 |
| na+-induced structural change of a soil bacterium, s34, and ca2+ requirement for preserving its original structure. | a drastic change in the outer membrane structure of a salt-sensitive soil bacterium, s34, related to the genus deinococcus was induced by 0.2 to 0.4% (wt/vol) nacl. the change was relieved by 6 mm cacl2 and induced by 1 mm egta. the results indicate the strong dependence of the organism on calcium. | 1997 | 9150234 |
| the sequences of heat shock protein 40 (dnaj) homologs provide evidence for a close evolutionary relationship between the deinococcus-thermus group and cyanobacteria. | the genes encoding for heat shock protein 40 (hsp40 or dnaj) homologs were cloned and sequenced from the archaebacterium halobacterium cutirubrum and the eubacterium deinococcus proteolyticus to add to sequences from the gene banks. these genes were identified downstream of the hsp70 (or dnak) genes in genomic fragments spanning this region and, as in other prokaryotic species, hsp70-hsp40 genes are likely part of the same operon. the hsp40 homolog from d. proteolyticus was found to be lacking a ... | 1997 | 9236279 |
| mutation induction by cross-links in dna of deinococcus radiodurans. | reversion of adenine auxotrophic strains of d. radiodurans by cross-links in dna was studied. mutation was induced in a wild-type but not in a mitomycin c sensitive mutant after irradiation with near uv (approximately 365nm) in the presence of 4,5',8-trimethylpsoralen (tmp). to get information on implication of cross-links in the observed mutation, cells containing monoadducts in dna were exposed to near uv in the absence of tmp. the mutation frequency of the wild-type increased with increasing ... | 1983 | 6847660 |
| against all odds: the survival strategies of deinococcus radiodurans. | bacteria of the genus deinococcus exhibit an extraordinary ability to withstand the lethal and mutagenic effects of dna damaging agents-particularly the effects of ionizing radiation. these bacteria are the most dna damage-tolerant organisms ever identified. relatively little is known about the biochemical basis for this phenomenon; however, available evidence indicates that efficient repair of dna damage is, in large part, responsible for the deinococci's radioresistance. obviously, an explanat ... | 1997 | 9343349 |
| isolation and characterization of the plasma membrane and the outer membrane of deinococcus radiodurans strain sark. | deinococcus radiodurans strain sark, although gram-positive, has a complex cell wall profile that includes an outer membrane-like structure. the outer cell envelope layers formed blebs throughout the growth cycle, which were shed as large vesicles (0.5-3.5 micron m in diameter) from approximately 5% of the cell population. instability was accentuated by treatment with 10% nacl, which released the outer membrane from all cells without disrupting the peptidoglycan layer, and provided an outer memb ... | 1981 | 7296407 |
| b12-dependent ribonucleotide reductases from deeply rooted eubacteria are structurally related to the aerobic enzyme from escherichia coli. | the ribonucleotide reductases from three ancient eubacteria, the hyperthermophilic thermotoga maritima (tm), the radioresistant deinococcus radiodurans (dr), and the thermophilic photosynthetic chloroflexus aurantiacus, were found to be coenzyme-b12 (class ii) enzymes, similar to the earlier described reductases from the archaebacteria thermoplasma acidophila and pyrococcus furiosus. reduction of cdp by the purified tm and dr enzymes requires adenosylcobalamin and dtt. datp is a positive alloste ... | 1997 | 9391052 |
| mutation of d. radiodurans in a gene homologous to ruvb of e. coli. | following the digestion of chromosomal dna of deinococcus radiodurans with a restriction enzyme a partial genomic library was constructed using lambda phage as a vector. a phage clone whose dna can complement the deficiency in a radiation-sensitive mutant of d. radiodurans was isolated. following the subcloning using phasmid vector, a hybrid plasmid containing 1.2 kb inserted dna was obtained. after the determination of nucleotide sequence, the deduced amino acid sequence showed close homology t ... | 1997 | 9447236 |
| evolution and horizontal transfer of an entire biosynthetic pathway for cytochrome c biogenesis: helicobacter, deinococcus, archae and more. | | 1998 | 9515711 |
| signature sequences in diverse proteins provide evidence of a close evolutionary relationship between the deinococcus-thermus group and cyanobacteria. | a number of proteins have been identified that contain prominent sequence signatures that are uniquely shared by the members of the deinococcus-thermus genera and the cyanobacterial species but which are not found in any of the other eubacterial or archaebacterial homologs. the proteins containing such sequence signatures include (1) the dnaj/hsp40 family of proteins, (2) dna polymerase i, (3) the protein synthesis elongation factor ef-tu, and (4) the elongation factor ef-ts. a strong affinity o ... | 1998 | 9608054 |
| restoration of the dna damage resistance of deinococcus radiodurans dna polymerase mutants by escherichia coli dna polymerase i and klenow fragment. | deinococcus radiodurans and other species of this genus share extreme resistance to ionizing radiation and many other agents that damage dna. d. radiodurans mutant strains defective in a deinococcal dna polymerase that is homologous with e. coli dna polymerase i are highly sensitive to dna damage. in the current work we have inquired whether e. coli dna pol i can substitute for d. radiodurans pol in partially or fully restoring to pol- d. radiodurans mutants the extreme dna damage-resistance typ ... | 1994 | 7504195 |
| high sensitivity of deinococcus radiodurans to photodynamically-produced singlet oxygen. | to study the sensitivity of two bacterial cell systems to photodynamic treatment and x-ray irradiation as part of a project to establish efficient procedures for waste water disinfection. | 1998 | 9712554 |
| defective transformation of chromosomal markers in dna polymerase i mutants of the radioresistant bacterium deinococcus radiodurans. | the transformation efficiency of six independently selected chromosomal markers (four for rifampicin resistance and two for acriflavine resistance) was found to be reduced by about 3 logs in a deinococcus radiodurans strain that was isogenic with wild type except for an insertional mutation in the pol gene that eliminated dna polymerase i activity (strain 6r1a). d. radiodurans strains uv17 and 303, previously obtained by chemical mutagenesis, were determined to be partially deficient in dna pol ... | 1994 | 7520974 |
| microbial communities of printing paper machines. | the microbial content of printing paper machines, running at a temperature of 45-50 degrees c and at ph 4.5-5, was studied. bacteria were prevalent colonizers of the machine wet end and the raw materials. a total of 390 strains of aerobic bacteria were isolated and 86% of these were identified to genus and species by biochemical, chemotaxonomic and phylogenetic methods. the most common bacteria found at the machine wet end were bacillus coagulans and other bacillus species, burkholderia cepacia, ... | 1998 | 9717292 |
| interchromosomal recombination in the extremely radioresistant bacterium deinococcus radiodurans. | deinococcus radiodurans and other members of the genus deinococcus are remarkable for their extreme resistance to ionizing radiation and many other agents that damage dna. we have recently shown that recombinational processes participate in interplasmidic repair following in vivo irradiation. we now present direct studies on interchromosomal recombination among chromosomes irradiated in vivo during stationary phase (four chromosomes per cell). following an exposure to 1.75 mrad (the dose require ... | 1995 | 7559335 |
| characterization of ribonuclease p rnas from thermophilic bacteria. | the catalytic rna component of bacterial rnase p is responsible for the removal of 5' leader sequences from precursor trnas. as part of an on-going phylogenetic comparative characterization of bacterial rnase p, the genes encoding rnase p rna from the thermophiles thermotoga maritima, thermotoga neapolitana, thermus aquaticus, and a mesophilic relative of the latter, deinococcus radiodurans, have been cloned and sequenced. rnas transcribed from these genes in vitro are catalytically active in th ... | 1993 | 7680125 |
| protein phylogenies and signature sequences: a reappraisal of evolutionary relationships among archaebacteria, eubacteria, and eukaryotes. | the presence of shared conserved insertion or deletions (indels) in protein sequences is a special type of signature sequence that shows considerable promise for phylogenetic inference. an alternative model of microbial evolution based on the use of indels of conserved proteins and the morphological features of prokaryotic organisms is proposed. in this model, extant archaebacteria and gram-positive bacteria, which have a simple, single-layered cell wall structure, are termed monoderm prokaryote ... | 1998 | 9841678 |
| glucosyl diglyceride lipid structures in deinococcus radiodurans. | the structures of two lipids from the radiation-resistant bacterium deinococcus radiodurans are reported here: 1,2-diacyl-3-alpha-glucopyranosyl-glycerol and 3-o-[6'-o-(1",2"-diacyl- 3"-phosphoglycerol)-alpha-glucopyranosyl]-1,2-diacylglycerol. these lipids are strikingly different from previously characterized polar lipids from this organism, in that they are not unique to the genus deinococcus and indeed have counterparts in both gram-negative and gram-positive bacteria. moreover, as examples ... | 1995 | 7730293 |
| repair of oxidized bases in the extremely radiation-resistant bacterium deinococcus radiodurans. | deinococcus radiodurans is able to resist and survive extreme dna damage induced by ionizing radiation and many other dna-damaging agents. it is believed that it possesses highly efficient dna repair mechanisms. to characterize the repair pathway of oxidized purines in this bacteria, we have purified, from crude extracts, proteins that recognize these oxidized bases. we report here that d. radiodurans possesses two proteins excising the oxidized purines (formamidopyrimidine and 8-oxoguanine) by ... | 1999 | 9864339 |
| peptidoglycan fine structure of the radiotolerant bacterium deinococcus radiodurans sark. | peptidoglycan from deinococcus radiodurans was analyzed by high-performance liquid chromatography and mass spectrometry. the monomeric subunit was: n-acetylglucosamine-n-acetylmuramic acid-l-ala-d-glu-(gamma)-l-orn-[(delta)gly-gly]-d-ala-d-ala. cross-linkage was mediated by (gly)2 bridges, and glycan strands were terminated in (1-->6)anhydro-muramic acid residues. structural relations with the phylogenetically close thermus thermophilus are discussed. | 1999 | 9864347 |
| targeted mutagenesis by duplication insertion in the radioresistant bacterium deinococcus radiodurans: radiation sensitivities of catalase (kata) and superoxide dismutase (soda) mutants. | deinococcus radiodurans r1 is extremely resistant to both oxidative stress and ionizing radiation. a simple and general targeted mutagenesis method was developed to generate catalase (kata) and superoxide dismutase (soda) mutants. both mutants were shown to be more sensitive to ionizing radiation than the wild type. | 1999 | 9882685 |
| isolation of deinococcus species from commercial oyster extract. | deinococci with radiation resistance greater than that of deinococcus radiophilus (atcc 27603) were isolated from three commercial oyster extracts stored at 4, 20, and 30 degreesc. during storage the number of other bacteria declined and deinococci became the predominant group in the microflora, particularly at 20 degreesc, although at 30 degreesc the number of deinococci as well rapidly declined. the results suggest that the natural habitat of deinococci is an aerobic environment containing a s ... | 1999 | 9925627 |
| bactericidal action of 308 nm excimer-laser radiation: an in vitro investigation. | the aim of the present study was to investigate the influence of 308 nm excimer-laser radiation on bacterial growth. six different bacterial strains (staphylococcus aureus, escherichia coli, streptococcus faecalis, lactococcis lactis, salmonella typhimurium, and deinococcus radiodurans) were exposed in vitro to various doses and energy densities of laser radiation. to exclude bacterial killing by supraphysiological heating, the temperature change in the samples during irradiation was measured. e ... | 1998 | 10023253 |
| sensitivity of selected bacterial species to uv radiation. | the effect of exposure of bacterial suspensions to uv radiation by means of the dose-response curves was assessed. the d37 and d10 values were used for subsequent statistical analysis of the results. the aim of this article is to evaluate the sensitivity to uv radiation of several microorganisms of different habitats (rhizobium meliloti, rhodobacter sphaeroides, escherichia coli, and deinococcus radiodurans), two mutants with nonfunctional sos dna repair system (r. meliloti reca- and e. coli rec ... | 1995 | 7765851 |
| dna repair in the extremely radioresistant bacterium deinococcus radiodurans. | deinococcus radiodurans and other members of the same genus share extraordinary resistance to the lethal and mutagenic effects of ionizing and u.v. radiation and to many other agents that damage dna. while it is known that this resistance is due to exceedingly efficient dna repair, the molecular mechanisms responsible remain poorly understood. following very high exposures to u.v. irradiation (e.g. 500 j m-2, which is non-lethal to d. radiodurans), this organism carries out extremely efficient e ... | 1994 | 7984097 |
| dust-borne bacteria in animal sheds, schools and children's day care centres. | a total of 316 bacterial strains, including psychrophiles, mesophiles and thermophiles, were isolated and identified from indoor dusts in schools, children's day care centres and animal sheds. several species which had not previously been reported from indoor environments were found: sphingomonas, brevibacterium, nocardiopsis, deinococcus and rhodococcus/gordona. a new psychrophilic actinomycete genus was also found in animal sheds, representing a new undescribed peptidoglycan type and an unusua ... | 1999 | 10212408 |
| dna polymerase c of the thermophilic bacterium thermus aquaticus: classification and phylogenetic analysis of the family c dna polymerases. | bacterial family c dna polymerases (dna pol iiis), the major chromosomal replicative enzymes, have been provisionally classified based on primary sequences and domain structures into three classes: class i (escherichia coli dna pol c-type), class ii (bacillus subtilis dna pol c-type), and class iii (cyanobacterial dna pol c-type), respectively. we have sequenced the structural gene encoding the dna pol c catalytic subunit of the thermophilic bacterium thermus aquaticus. this gene, designated the ... | 1999 | 10229580 |
| novel ionizing radiation-sensitive mutants of deinococcus radiodurans. | two new loci, irrb and irri, have been identified in deinococcus radiodurans. inactivation of either locus results in a partial loss of resistance to ionizing radiation. the magnitude of this loss is locus specific and differentially affected by inactivation of the uvra gene product. an irrb uvra double mutant is more sensitive to ionizing radiation than is an irrb mutant. in contrast, the irri uvra double mutant and the irri mutant are equally sensitive to ionizing radiation. the irrb and irri ... | 1994 | 8002565 |
| evolutionary relationships among photosynthetic prokaryotes (heliobacterium chlorum, chloroflexus aurantiacus, cyanobacteria, chlorobium tepidum and proteobacteria): implications regarding the origin of photosynthesis. | the presence of shared conserved insertions or deletions in proteins (referred to as signature sequences) provides a powerful means to deduce the evolutionary relationships among prokaryotic organisms. this approach was used in the present work to deduce the branching orders of various eubacterial taxa consisting of photosynthetic organisms. for this purpose, portions of the hsp60 and hsp70 genes, covering known signature sequence regions, were pcr-amplified and sequenced from heliobacterium chl ... | 1999 | 10361294 |
| interplasmidic recombination following irradiation of the radioresistant bacterium deinococcus radiodurans. | deinococcus radiodurans r1 and other members of the eubacterial family deinococcaceae are extremely resistant to ionizing radiation and many other agents that damage dna. for example, after irradiation, d. radiodurans can repair > 100 dna double-strand breaks per chromosome without lethality or mutagenesis, while most other organisms can survive no more than 2 or 3 double-strand breaks. the unusual resistance of d. radiodurans is reca dependent, but the repair pathway(s) is not understood. recen ... | 1994 | 8002574 |
| phylogenetic analysis of sequences from diverse bacteria with homology to the escherichia coli rho gene. | genes from pseudomonas fluorescens, chromatium vinosum, micrococcus luteus, deinococcus radiodurans, and thermotoga maritima with homology to the escherichia coli rho gene were cloned and sequenced, and their sequences were compared with other available sequences. the species for all of the compared sequences are members of five bacterial phyla, including thermotogales, the most deeply diverged phylum. this suggests that a rho-like gene is ubiquitous in the bacteria and was present in their comm ... | 1994 | 8051015 |
| [high resistance of some oligotrophic bacteria to ionizing radiation]. | the resistance against ionizing radiation of seven cultures of oligotrophic and eutrophic bacteria was investigated in the interval 0-360 gr/h. it is determine that all of tested bacteria are distributed into three groups according to the lever of their resistance. most resistant were: methylobacterium organophilum, pedodermatophilus halotolerans (ld50 = 270 cr/h). these organisms are close to deinococcus radiodurans in the survival. middle resistance shown water-born ring-forming bacteria flect ... | 1993 | 8114644 |
| whole-genome shotgun optical mapping of deinococcus radiodurans. | a whole-genome restriction map of deinococcus radiodurans, a radiation-resistant bacterium able to survive up to 15,000 grays of ionizing radiation, was constructed without using dna libraries, the polymerase chain reaction, or electrophoresis. very large, randomly sheared, genomic dna fragments were used to construct maps from individual dna molecules that were assembled into two circular overlapping maps (2.6 and 0.415 megabases), without gaps. a third smaller chromosome (176 kilobases) was id ... | 1999 | 10477518 |
| sequencing, targeted mutagenesis and expression of a reca gene required for the extreme radioresistance of deinococcus radiodurans. | deinococcus radiodurans and other members of the same genus share extreme resistance to ionizing radiation and many other agents that damage dna. a dna damage-sensitive and natural transformation-deficient strain generated by chemical mutagenesis (strain rec30) was found to be defective in a gene that has extended homology with reca of escherichia coli. upon transformation with a chromosomal dna fragment that contained this deinococcal reca gene from wild-type (wt) d. radiodurans both dna damage ... | 1994 | 8163172 |
| dna deoxyribophosphodiesterase and an activity that cleaves dna containing thymine glycol adducts in deinococcus radiodurans. | deinococcus radiodurans is the most radioresistant bacterium discovered to date. recently it has been demonstrated that this organism contains the dna repair enzyme uracil-dna glycosylase and an apurinic/apyrimidinic (ap) endonuclease that may function as part of a dna base excision repair pathway. we demonstrate here that a dna deoxyribophosphodiesterase activity that acts on incised ap sites in dna to remove deoxyribose-phosphate groups is found in lysates prepared from d. radiodurans cells. t ... | 1994 | 8183999 |