INTERNATIONALJOURNAL OF SYSTEMATICBACTERIOLOGY, July 1981, p. 353-360 Vol. 31, No. 3 0020-7713/81/030353-08$02.00/0

Nomenclature for “Micrococcus radiodurans” and Other Radiation-Resistant Cocci: Deinococcaceae fam. nov. and Deinococcus gen. nov., Including Five Species

B. W. BROOKST AND R. G. E. MURRAY Department of Microbiology and Immunology, University of Western Ontario, London, Ontario Canada, N6A 5Cl

The data assembled by Brooks et al. (Int. J. Syst. Bacteriol. 30:627-646, 1980) suggest that the radiation-resistant, red, gram-positive, tetrad-forming cocci ex- emplified by “Micrococcus radiodurans” (not on Approved Lists of Bacterial Names [Skerman et al., Int. J. System. Bacteriol. 30:225-420,19801) are a distinct natural group separate from Micrococcus. The nomenclature proposed here for these organisms utilizes specific epithets used in the original names of these organisms, which names were made illegitimate by omission from the Approved Lists. One species is added to those named before 1 January 1980. The proposals are as follows: Deinococcaceae fam. nov. Deinococcus gen. nov. (type ) D. radiodurans nom. nov. (type species) D. radiophilus nom. nov. D. proteolyticus nom. nov. D. radiopugnans sp. nov. Species incertae sedis D. erythromyxa nom. nov. Descriptions of the taxa are provided.

‘‘Micrococcus radiodurans” (19) (names in (2, 3) suggested that these strains should be quotation marks were not included on the Ap- excluded from the genus Micrococcus because proved Lists of Bacterial Names [21]) was the of the nature of the (20, 27) and lipid name given to a remarkable radiation-resistant (12) constituents in addition to radiation resist- coccus isolated by Anderson et al. (1) from irra- ance. These strains, under the common name diated meat. Most of the detailed studies of this “Micrococcus radiodurans,” were placed in organism have used the R1 strain of Anderson et Bergey’s Manual (4) in the incertae sedis sec- al. or the Sark strain (R. G. E. Murray and C. F. tion appended to Micrococcus for determinative Robinow, Abstr. 7th Int. Congr. Microbiol., p. purposes. The recent taxonomic study by Fel- 427, 1958), which was later shown to be closely tham (9) also suggests that “M. radiodurans” related (5). Structural and biochemical analysis and its relatives are distinct from conventional of the cell walls of these two strains showed Micrococcus species. This distinction has been distinct differences from Micrococcus species: a confiied by Brooks et al. (5), with additional complex profile in sections (15, 22, 25) and L- evidence supporting and amplifying the earlier ornithine with di- or triglycine as the interpep- recognition by Davis et al. (8), Lewis (17), and tide bridge in the peptidoglycan (5,20, 26). Fur- Kobatake et al. (13) of distinctive organisms thermore, the predominant fatty acid in lipid within the radiation-resistant group. Recent extracts of these cells was a 16:l component (5, structural observations on these organisms (15, 10, 12), which is commonly associated with 22, 23) emphasize the unique features of their gram-negative . cell walls and membranes. The application of Hill (11) aligned the radiation-resistant, red- ribosomal ribonucleic acid oligonucleotide se- pigmented, -positive micrococci with quence catalog data provides the best evidence other similarly pigmented, gram-positive orga- in support of the thesis that these organisms are nisms such as and M. agilis. unrelated or are very distantly related to Micro- Subsequent taxonomic analysis by Baird-Parker coccus (5). The situation is made the more complex be- t Present address:Department of Veterinary Microbiology, cause the name “M. radiodurans,” as well as University of Guelph, Guelph, Ontario, Canada. “M. radiophilus” (17) and “M. radioproteolyti- 353 354 NOTES INT. J. SYST.BACTERIOL. cus” (13), which may be considered relatives, Resistant to 1.5 Mrad of gamma radiation and were omitted from the Approved Lists of Bac- exposure to 1,800 ergs/cm2 per s of ultraviolet terial Names (21). Therefore, it is the intent of radiation for 10 min. this paper to establish a nomenclature and ap- Guanine-plus-cytosine (G+C) content of the propriate descriptions of the taxa to provide a deoxyribonucleic acid (DNA) is 67 mol% (by legitimate basis for referring to these organisms Tm)* and to stimulate studies of this unique group. Type strain: ATCC (American Type Culture No disrespect is intended toward the original Collection) 13939 (=UWO [Collection in the De- authors of the specific epithets proposed in this partment of Microbiology and Immunology, paper; the provisions of the Bacteriological Code University of Western Ontario] 288). (1976 revision) do not allow their inclusion as Variations in cell wall structure, reduction of contributions to new combinations of names. nitrates, tolerance to sodium chloride, propor- The taxonomic treatment put forward in this tion of fatty acid components, and loss of pig- paper is based on the comparative data pub- mentation have been observed in strains in- lished by Brooks et al. (5) and on their more cluded in D.radiodurans. Some greater varia- detailed studies of representative strains of the tions among strains assigned to D. radiodurans apparent phenotypic clusters. It is clear that the e.g., strains 1083, G+C = 70 mol%; see Table 2) red-pigmented micrococci, M. roseus and M. will demand detailed study in the future in terms agilis, are species of Micrococcus Cohn 1872 of relatedness and species assignment of the (14) and are quite separate from the radiation- strains. resistant “M. radiodurans” (Table 1) and the Description of Deinococcus gen. nov. Dei organisms that resemble it. Therefore, we here- no.coc’cus. Gr. adj. deinos strange or unusual; by conserve the elegant and effective specific Gr. n. coccus a grain or berry; M.L. masc. n. epithet “radiodurans” associated with this or- Deinococcus unusual coccus. ganism (19) in the new name Deinococcus ra- Cells spherical, 0.5 to 3.5 pm in diameter, diodurans. The new generic name Deinococcus occurring singly and in pairs and dividing in two implies that these cocci have remarkable prop- planes to form tetrads or tablets of cells. Non- erties. The appropriate descriptions follow. motile. No resting stages known. Gram positive. Description of the type strain of D. m- Chemoorganotrophic; metabolism is respira- diodumns nom. nov. M.L. adj. ra.di.o. tory. Glucose may be metabolized, but acid is du’rans. L.n. radiatio radiation; L. part. adj. produced from only a limited number of carbo- durans enduring; radiodurans resisting radia- hydrate substrates, if at all. Catalase is pro- tion. duced. Carotenoid pigments usually are present, Spheres, 1.5 to 3 pm in diameter, occurring and colonies are usually pink to brick red, singly and in pairs and dividing in two planes to Aerobic. Optimal growth temperature is 25 to form tetrads or tablets of cells. Nonmotile. 35°C. The peptide subunit of the cell wall contains Several distinct cell wall layers are visible in L-alanine, D-glutamic acid, and L-ornithine. The thin sections, and the walls may contain lipopro- interpeptide bridge contains glycine. Teichoic tein, The interpeptide bridge of the peptidogly- acids are absent. The cell wall consists of at least can contains glycine, and the peptide subunit four layers and has a total thickness of 130 to contains L-alanine, D-glutamic acid, and L-orni- 140 nm. The peptidoglycan-containing layer is thine. Teichoic acids are absent. fenestrated. The outermost layer consists of hex- Many strains are resistant to 1.5 Mrad of agonally packed protein subunits. gamma radiation and to exposure to 1,800 ergs/ The predominant fatty acid component is pal- cm2 per s of ultraviolet radiation for 10 min. mitoleate. No branched-chain fatty acids are The fatty acid component palmitoleate ac- present. counts for at least 25% of the total fatty acid Colonies are red, smooth, and convex with a composition. regular edge. Multiple carotenoids are present. The G+C content of the DNA ranges from 62 Chem0 organotrop hic; met a bolism is strictly to 70 mol% (by Tm). respiratory. Acid production from some carbo- Type species: . hydrates (glucose and fructose) is variable. Fruc- Family relationship of the genus Deino- tose, glycerol, glucose, and mannose are utilized, coccus. Results of comparative cataloging of but no acid is produced in standard broth. 16s ribosomal ribonucleic acid taken together Strictly aerobic. Optimal growth temperature with the results of DNA homology, the analysis is 30°C. All strains grow in the presence of 1% of fatty acid composition, and the analysis of cell NaCl and most grow in 5% NaCl in media. wall structure and composition indicate a very Nitrates are not reduced to nitrites. distant relationship between D. radiodurans TABLE1. Characters useful in differentiatingM. roseus, M. agilis, and D. radiodurans Character

Fenestrated Resist- Strain ~~i~ Growth on Growth at Nitrate re- Esculin hy- ONP~b Peptidoglycan type Lipoprotein Predominant peptidogly- 5%NaCl 37OC duction drolysis in cell wall" in cell wall' fatty acid can-con- '5 Mrad taining of radia- laver tion M. roseus 74 + (100%) + (100%) + (100%) Variable - (0%) L-Lys-L-Alaa_*" - (0%) Not 15:O Absent No (+ 71%) sought branched

M. agilis 64' - (0%) - (0%) - (0%) - (0%) - (0%) L-Lys-L-Thr- - (OW)' Not 15:O Absent No L-Ala3' sought branched

D. radio- 67 Variable + (+ 96%) Variable - (+ 8%) - (0%) L-Om, di- or - (0%) Present 16:l Present Yes durans (+ 25%) (+ 25%) triglycineP Determined on type strain. o-Nitrophenyl-P-D-galactosidase.These results do not support those of Kocur and Schliefer (14). This is a potentially useful character. Work and Griffiths (27) and Lancy and Murray (15) have detected lipoprotein in the cell wall of "M. radiodurans." Cell walls of M. roseus have not been analyzed specifically for lipoprotein. 'Schliefer and Kandler (20). Kocur and Schliefer (14). All strains were nonmotile but were previously reported as motile (14). Work (26).

w cn 01 356 NOTES INT. J. SYST.BACTERIOL.

TABLE2. Differential characters of miscellaneous strains of red-pigmented cocci Character

Acid from Growth in Predomi- Strain Nitrate glucose mol% G Resist- Branched- reduc- in + in ance to Cell size Peptidoglycan presence gamma (pm) type in cell wall of 5% nant fatty acid fatty tion stand- DNA radiation NaCl acid ard me- dium D.radiophilus - - 62 Yes” 1.0-2.0 L-Orn-Glyz* + 16:1 Not de- UWO 1055 tected D.proteolyticus - + 65 Yes“ 1.0-2.0 L-o~-G~Y~* - 161 Not de- UWO 1056 tected D.radiopugnans + - 70 Yesd 1.0-2.0 Om-Gly, - 16:1, 1710 15:O UWO293 D.erythromyxa + - 71 Yese 1.0-2.5 L-Lys-L-Ala3-4f + 16:0, 18:l Not pres- UWO 1045 ent D.radiodurans + - 70 YesR 1.5-3.0 Om-Gly, - 15:1, 16:l Not pres- UWO 1083 ent

~ Lewis (17). * Sleytr et al. (23). Kobatake et al. (13). Davis et al. (8). Dl0= 0.127 to 0.254 Mrad (R. G. E. Murray, D. G. Storey, and J. L. Whitby, unpublished data). Schliefer and Kandler (20). E. A. Christensen, Statens Seruminstitut, Copenhagen, Denmark, personal communication.

and M. roseus (5). For these multiple reasons, Several distinct cell waU layers are visible in we believe that these organisms should not be thin section, and the cell wall contains lipopro- assigned to the same family. tein. L-Ornithine is present in the peptide sub- In the eighth edition of Bergey’s Manual (6), unit of the peptidoglycan; exceptions may occur. three families (, Streptococca- Many strains are resistant to high levels of ceae, and Peptococcaceae) are included in part gamma and ultraviolet radiation. 14, Gram-Positive Cocci. The inclusion of D. The G+C content of the DNA ranges from 62 radiodurans in any of these three families is not to 70 mol% (by Tm). appropriate. Therefore, Deinococcaceae fam. Type genus: Deinococcus. nov. is proposed with Deinococcus as the type Taxonomic status of other radiation-re- genus. For determinative reasons (“gram-posi- sistant, red-pigmented strains. On the basis tive cocci” being a convenient assembly) and of fatty acid composition, in terms of both com- until strong phylogenetic or other data demand ponents detected and relative percentage of in- some other alignments, this new family should dividual components, Brooks et al. (5) distin- remain in Part 14 of Bergey’s Manual, or its guished eight strains (formerly known as M. equivalent. roseus UWO 293, M. roseus UWO 294, “M. Description of the family Deinococcuceae radiophilus” UWO 1055, “M. radioproteolyti- fam. nov. Dei * no COC ca’ce ae. M.L. masc. n. cus” UWO 1056, M. roseus UWO 1045, M. ro- Deinococcus type genus of the family; -aceae seus UWO 1088, “M. radiodurans” UWO 1083, ending to denote family; M.L. fem. pl. n. Dei- and “M. radiodurans” UWO 1085) from M. nococcaceae the Deinococcus family. roseus, M. agilis, and “M. radiodurans” (now Cells spherical, 0.5 to 3.5 pm in diameter, D. radiodurans). At the same time, the fatty characteristically dividing in more than one acid compositions and the analyses of the cell plane to form tetrads or tablets. Nonmotile. wall profiles of these eight strains indicate that Resting stages are not produced. Gram positive. these organisms can be divided into five clusters Chemoorganotrophic; metabolism is respira- (Table 2). The strains formerly known as “M. tory. Acid without gas is produced from glucose, radiophilus” (UWO 1055) and “M. radioproteo- when attacked. Zyticus” (UWO 1056) were distinct from each Nutritional requirements are variable. other and from the other six strains. M. roseus Catalase positive, strains UWO 293 and 294 were similar to each Aerobic. other, as were M. roseus strains UWO 1045 and The fatty acid component palmitoleate ac- UWO 1088 and “M.radiodurans” strains UWO counts for at least 25%of the fatty acid compo- 1083 and UWO 1085. sition. Determination of cell wall profiles and of fatty VOL. 31, 1981 NOTES 357 acid composition has provided differential char- that this organism was more active in digesting acters for taxonomic purposes at the level of proteins (milk, soya, and gelatin) than was “M. family or genus, but these are of limited value radiodurans” and expressed this in forming the for species identification. Unfortunately, the epithet. We retain this approach. chemistry of the cell walls of the eight strains, Brooks et al. (5) and Sleytr et al. (23) reported beyond establishing the peptidoglycan type, has additional characters for this organism: the fatty not been studied in detail. acid composition of this strain and the cell wall Taxonomic status of the organism for- profile are similar to those of D. radiodurans merly known as “M. diophilus.” The or- and D. radiophilus. Acid production from glu- ganism formerly known as “M. radiophilus” cose and fructose in the standard medium, non- UWO 1055 was isolated by Lewis (17), who specific esterase banding patterns, and results described it as a new species which differed from from studies on DNA homology support the “M. radiodurans” in size, tolerance to sodium recognition of this organism as a separate spe- chloride, and degree of resistance to gamma cies. The name Deinococcus proteolyticus nom. radiation. No type strain was designated, but nov. is proposed for this organism. Lewis described only a single strain (ATCC Description of the type strain of D. pro- 27603); according to Rule 18c of the Bacteriolog- teolyticus nom. nov. Pro. te - o - ly’ti - cus. M.L. ical Code (16), this strain must be accepted as m. adj. proteolyticus proteolytic. the type. The name Deinococcus radiophilus Spheres, 1.0 to 2.0 pm in diameter, occurring nom. nov. is proposed for this organism. singly and in pairs and dividing in two planes to Description of the type strain of D. di- form tetrads. Nonmotile. ophilus nom. nov. Ra-di-o’phil-us. M.L. n. The peptide subunit of the cell wall contains radiatio radiation; Gr. adj. philos loving; M.L. L-ornithine, and the interpeptide bridge contains adj. radiophilus radiation loving. glycine. The cell wall consists of at least three Spheres, 1.0 to 2.0 pm in diameter, occurring distinct layers. singly and in pairs and dividing in two planes to The predominant fatty acid component is pal- form tetrads. Nonmotile. mitoleate. No branched-chain fatty acids are The peptide subunit of the cell wall contains present. L-ornithine, and the interpeptide bridge contains Colonies are orange-red, smooth, and convex glycine. The cell wall consists of at least three with a regular edge. Multiple carotenoids are distinct layers. present. The predominant fatty acid component is pal- Chemoorganotrophic; metabolism is respira- mitoleate. No branched-chain fatty acids are tory. Acid but no gas is produced from glucose present. and fructose in standard broth. Milk is pepto- Colonies are orange-red, smooth, and convex nized and gelatin is liquefied. with a regular edge. Multiple carotenoids are Strictly aerobic. Optimal growth temperature present. is 30°C. Grows in the presence of 1% NaCl. Chemoorganotrophic; metabolism is strictly Nitrates are not reduced to nitrates. Catalase respiratory. No acid is produced in standard positive. broth containing glucose or fructose. Resistant to 1.5 Mrad of gamma radiation. Strictly aerobic. Optimal growth temperature G+C content of the DNA is 65 mol% (by Tm). is 30°C. Grows in the presence of 5% NaCl. Type strain: CCM 2703 (= UWO 1056). Nitrates are not reduced to nitrates. Catalase Taxonomic status of the organism for- positive. merly known as the “Davis” or “haddock” Resistant to 1.5 Mrad of gamma radiation. strain of M. roseus. In 1964, Davis et al. (8) G+C content of the DNA is 62 mol% (by Tm). reported the isolation of a radiation-resistant Type strain: ATCC 27603 (= UWO 1055). coccus from haddock tissue (UWO 293). It was Taxonomic status of the organism for- distinguished from “M. radiodurans” by size, merly known as “M. diopmteolyticus.” nitrate reduction, and gelatin hydrolysis. Davis “M. radioproteolyticus” was isolated by Koba- et al. did not identify their isolate, but Girard take et al. (13) and was described as a new (10) studied it and included it with M. roseus species. No type strain was designated, but be- despite the findings of Davis et al. It is evident cause only a single strain was described (Czech- from the study of Brooks et al. (5) that the Davis oslovak Collection of Microorganisms [CCM] strain is a member of neither M. roseus nor the strain 2703), it is the type strain by monotypy genus Micrococcus. (Rule 18c). The specific epithet is illegitimate The fatty acid composition of the Davis isolate (Rule 12a) because it expresses more than a is distinct from that of D. radiodurans in terms single concept. Kobatake et al. (13) recognized of the components and, in particular, their rela- 358 NOTES INT. J. SYST.BACTERIOL.

tive proportions. A 15:O branched-chain fatty thromyxa is ATCC 187 (= UWO 1045). Strain acid, not detected in D. radiodurans, is present UWO 1088 will have to be left out of considera- in the Davis isolate. The profile of the cell wall tion for this taxon because repeated assessment of the Davis isolate consists of at least three of its peptidoglycan constitution reveals the distinct layers and is thus similar to that ob- presence of m-diaminopimelic acid and no trace served in D. radiophilus and D. proteolyticus. of either ornithine or lysine (E. Stackebrandt, This information as well as DNA homology data Technische Universitat, Munich, West Ger- (5) supports the recognition of this isolate as a many, personal communication). However, in distinct species. Deinococcus radiopugnans is other respects the phenotypes of these two or- suggested as an appropriate name for this organ- ganisms, including the fatty acid constituents, ism, and UWO 293 is proposed as the type strain. are remarkably similar (5). Description of the type strain of D. radi- Description of the type strain of D. ery- opugnans sp. nov. Ra-di-o-pug’nans. L. n. thromyxa nom. nov. E - ry .thro - my’xa. Gr. radiatio radiation; L. part. adj. pugnans fighting adj. erythros red; Gr. n. myxa slime or mucus; or resisting; M.L. adj. radiopugnans radiation M.L. n. erythromyxa red slime. resisting. Spheres, 1.0 to 2.0 pm in diameter, occurring Spheres, 1.0 to 2.0 pm in diameter, occurring singly and in pairs and dividing in two planes to singly and in pairs and dividing in two planes to form tetrads. Nonmotile. form tetrads or tablets of cells. Nonmotile. The cell wall consists of two layers. The pep- The cell wall consists of at least three layers, tidoglycan is of the L-Lys-L-A1a3-4 type. The and the peptidoglycan-containing layer is fen- peptidoglycan-containing layer is not fenes- estrated. trated. Two fatty acid components, palmitoleate and Two fatty acid components, palmitate and heptadecanoate, present in approximately equal oleate, are present in approximately equal pro- proportion, together account for at least 50% of portion and together account for at least 60% of the total fatty acid composition. A 15-carbon, the total fatty acid composition. No branched- branched-chain, saturated fatty acid component chain fatty acids are present. is present. Colonies are red, smooth, and convex with a Colonies are orange-red, smooth, and convex regular edge. Multiple carotenoids are present. with a regular edge. Multiple carotenoids are Chemoorganotrophic; metabolism is strictly present. respiratory. No acid is produced from glucose in Chemoorganotrophic; metabolism is strictly standard medium. Catalase positive. respiratory. No acid is produced from glucose in Aerobic. Optimal growth temperature is 30°C. standard medium. Catalase positive. Grows in the presence of 5% NaC1. Nitrates are Strictly aerobic. Optimal growth temperature reduced to nitrites. is 30°C. Resistant to gamma radiation; the level is Grows in the presence of 1%NaCl. Nitrate is uncertain, but it is in the region of 1 Mrad. reduced to nitrite. G+C content of the DNA is 71 mol% (by Tm). Resistant to 1.5 Mrad of gamma radiation. Type strain: ATCC (= UWO 1045). G+C content of the DNA is mol% (by Tm). Intrageneric relationship of D. radiophi- Type strain: ATCC 19172 (= UWO 293). lus, D. proteolyticus, D. radiopugnans, and Smooth and rough variants, as well as variants D. erythmmyxa D. radiophilus, D. proteo- with less pigment, may occur. The 15-carbon, lyticus, and D. radiopugnans have complex cell saturated, branched-chain fatty acid component walls with several obvious layers and a fatty acid may be absent. component, palmitoleate, which accounts for at Taxonomic status of strains formerly least 25% of the total fatty acid composition. All identified as members of M. mseus (UWO three strains have features characteristic of the 1045 and UWO 1088). M. roseus strains UWO genus Deinococcus; they are resistant to 1.5 1045 and 1088 have similar cell wall profiles and Mrad of gamma radiation and have a peptido- fatty acid compositions but differ in both re- glycan of the L-Om-Glya type. spects from the type strain of M. roseus, ATCC However, results of DNA homology studies 186. On the basis of these two complex charac- (5) between D. radiodurans UWO 298 and D. ters and DNA homology (5), M. roseus strain radiophilus, D. proteolyticus, and D. radiopug- UWO 1045 is recognized as belonging to a species nans indicate only low homologies (4, 10, and separate from M. roseus. Because M. roseus 12%, respectively). Similarly, results of DNA UWO 1045 was formerly called “Sarcina ery- homology studies between D. radiopugnans and thromyxa” (7), the name Deinococcus erythro- D. radiodurans UWO 298, D. radiophilis, and myxa is suggested. The type strain of D. ery- D. proteolyticus also indicate low homologies VOL. 31, 1981 NOTES 359

(17,4, and 8%, respectively). Results of compar- However, the values vary by as much as 20 to ative cataloging of 16s ribosomal ribonucleic 100% according to the method used, notably acid (5) indicate that there are 320 common cells dried on glass versus cells dried on a paper bases between D. radiodurans UWO 298 and D. strip. radiopugnans, which indicates that these two Radiation resistance is an attractive and selec- strains are related. tive character but, as discussed in the previous This information indicates that D. radiophi- publication (3,it is mutable (13) and may not lus, D. proteolyticus, and D. radiopugnans serve to distinguish all the near or distant rela- should be aligned with the genus Deinococcus. tives of this unusual family of bacteria. However, the low DNA homology values and (This paper derives in part from a thesis sub- the small number of positive characters used for mitted by B. W. B. to the University of Western description make it likely that some or all of Ontario in partial fulfillment of the requirements these will have to be reassessed as members of for the MSc. degree.) the genus Deinococcus at some time in the fu- We are grateful for continuing support by the Medical ture. Research Council of Canada. The generic relationship of D. erythromyxa is We acknowledge the advice of D. E. Gerber, Department difficult to assess, because there is limited infor- of Classical Studies, University of Western Ontario concerning an appropriate generic name. We are particularly appreciative mation suggesting distinction from both Micro- of the assistance of J. L. Whitby and D. G. Storey in deter- coccus and Deinococcus. The cell wall profile is mining radiation sensitivity, E. Stackebrandt for the typifica- distinct from those of strains included in M. tion of peptidoglycan, and E. Lessel for nomenclatural advice. roseus, but the cell wall of D. erythromyxa does REPRINT REQUESTS not have as many obvious layers as are seen in Address reprint requests to : Dr. R. G. E. Murray, Depart- other species included in the genus Deinococcus. ment of Microbiology and Immunology, University of Western The peptidoglycan of D. erythromyxa is of the Ontario, London, Ontario, N6A 5C1, Canada. L-Lys-L-Ala3-4type found in M. roseus strains. LITERATURE CITED However, the fatty acid profiles of M. roseus 1. Anderson, A. W., H. C. Nordan, R. F. Cain, G. Par- (type strain) and D. erythromyxa are distinctly rish, and D. Duggan. 1956. Studies on a radio-resist- different. We find that the resistance of strains ant micrococcus. I. The isolation, morphology, cultural to gamma radiation is different but overlapping characteristics and resistance to gamma radiation. Food (M. roseus UWO 1057, type strain, DlO = 0.075 Technol. 10575-577. to 0.157 Mrad; D. erythromyxa UWO 1045, Dl0 2. Baird-Parker, A. C. 1963. A classification of micrococci and staphylococci based on physiological and biochem- = 0.127 to 0.254 Mrad, according to unpublished ical tests. J. Gen. Microbiol. 38:363-387. data of R. G. E. Murray, D. G. Storey, and J. L. 3. Baird-Parker, A. C. 1970. The relationship of cell wall Whitby). Unfortunately, there are no homology composition to the current classification of staphylo- cocci and micrococci. Int. J. Syst. Bacteriol. 20:483-490. data or comparative cataloging of 16s ribosomal 4. Baird-Parker, A. C. 1974. Part 14, Gram-positive cocci, ribonucleic acid of M. roseus and D. erythro- family I Micrococcaceae, p. 478-489. In R. E. Buchanan myxa strains available. So, in the absence of a and N. E. Gibbons (ed.), Bergey's manual of determi- more appropriate niche, the species D. erythro- native bacteriology, 8th ed. The Williams & Wilkins myxa is included in the genus Deinococcus as a Co., Baltimore. 5. Brooks, B. W., R. G. E. Murray, J. L. Johnson, E. species incertae sedis awaiting further study and Stackebrandt, C. R. Woese, and G. E. Fox. 1980. a more informed assignment. We can hope for a Red-pigmented micrococci: a basis for . Int. bigger collection of anomalous strains for a com- J. Syst. Bacteriol. 30:627-646. parative study. 6. Buchanan, R. E., and N. E. Gibbons (ed.). 1974. Ber- gey's manual of determinative bacteriology, 8th ed. The Regarding radiation resistance. It is worth WiUiams & Wilkins Co., Baltimore. noting that there is little consistency in the 7. Chester, F. D. 1901. A manual of determinative bacteri- methods applied to determining radiation resist- ology. The MacMillan Co., New York. ance and providing an effective comparison of 8. Davis, N. S., G. J. Silverman, and E. B. Masurovsky. 1963. Radiation-resistant, pigmented coccus isolated organisms in this regard. Until some effective from haddock tissue. J. Bacteriol. 86:294-298. approach to comparable data is agreed upon, we 9. Feltham, R. K. A. 1979. A taxonomic study of the Micro- are not prepared to provide figures that are coccaceae. J. Appl. Bacteriol. 47:243-254. different from those expressed in the literature. 10. Girard, A. E. 1971. A comparative study of the fatty acids of some micrococci. Can. J. Microbiol. 17: 1503-1508. Our preliminary data (unpublished) confirm 11. Hill, L. R. 1959. The Adansonian classification of the that all of the organisms selected as representa- staphylococci. J. Gen. Microbiol. 20:277-283. tive strains of Deinococcus species are remark- 12. Knivett, V. A., J. Cullen, and M. J. Jackson. 1965. ably resistant to gamma radiation and show a Odd numbered fatty acids in Micrococcus radiodurans. Biochem. J. 96:2c-3c. range of Dlo values of 0.100 to 0.547 Mrad, which 13. Kobatake, M., S. Tamabe, and S. Hasegawa. 1973. probably corresponds to a sterilizing dose (60Co; Nouveau micrococcus radioresistant a pigment rouge, in air) approximating six times those values. isole de feces de Lama glama, et son utilisation come 360 NOTES INT. J. SYST.BACTERIOL.

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