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The Vitamin Requirements of Kurthia zopfii and Kurthia gibsonii
System. Appl, Microbiol. 4, 439-443 (1983)
Depart ment of Microbiology, University of Reading, Readin g RG1 5AQ, England
The Vitamin Requirements of Kurthia zopjii and Kurthia
gibsonii STEVEN SHAWl and RONALD M . KEDDIE
Received April 19, 1983
Summary T he vitam in requirements of 17 K. gibsonii mains, 41 K. zopfii strains and 11 presumptive Kurthia isolates which could not be assigned to either species, were determin ed. When supplied with Casa mino acids and /or Casito ne the K. gibsonii strains required bio tin + th iamin e for grow th whereas the K. ~opfii strai ns required biotin + th iam ine + pa ntothenic acid . Th e difference in their requirements pr ovides support for the existence of the two species within th e genus. Eight of rhe 11 pr esu mptive Kurthia isolates had vita min requ irement s different fro m bot h K. zopfii and K. gibsonii; their taxon omic position remained unr esolved.
Key words: Kurthia - Kurtbia zopfii - Kurthia gibsonii - Vitamin requirements T axonomy
Introduction The genus Kurthia was d escrib ed as monospecific in Bergey's M anual (Keddie and Rogosa, 1974) but based on the re sults of a numerical taxonomic study Shaw an d Keddie (1983) proposed th at a second species, K. gibsonii, sho uld be recognized. N o information is ava ilable on th e nutritional requirements of Kurthia spp. other th an tha t growth occurs only in co mplex media (Keddie and Rogosa, 1974; Keddie, 1981). Therefore in the present study the vitamin requirement s of 17 K. gibsonii and 41 K. zopfii strains (Table 1) studie d by Shaw and Keddie (1983) were dete rm ined. The aim s we re to find out if eac h species was hom ogeneou s in vitamin requirements and whether o r not a study of th e vitamin requ irements wo uld reveal further differen ces between th e two species . Shaw and Keddie (1983) also described 11 Kurthia-like strai ns wh ich confo rmed in mo st or all respects to the definition of Kurthia in Bergey's Manua l (Keddie and Rogosa, 1974), but which were distinct
1
Present address: Watney Mann & T ruman Brewers Ltd ., London SW14 8]D, England.
29 Systematic and Applied Microb iology. Vol. 4
440
S.Shaw and R.M.Keddie
Table 1. Vitamin requirements of the strains studied when supplied with Casamino acids and/or Casitone Species etc. (Shaw and
Laboratory strain number
Name or source
Strain number
K1 K2 K3 K6, K8+, K9, K12, K30, K50 K27, K69 K29 K31 K57 K68 K75, K79
Kurthia sp. Kurthia sp. Kurthia sp.
NCIB 9756 NCIB 9757 NCIB 9758"
Vitamins required
Keddie, 1983) K. gibsonii
K. zopfii
K4++ K5 K7, Kll, K13, K14, K15, K16, K17, K18, K19, K26, K32, K33, K34+, K54, K56, K84, K85, K86, K88 K35 K36 K37, K40 K38 K39++ K41, K42 K43, K44, K61 K65, K66, K71 K58++ K72, K74, K76, K78, K80
Meat Hen faeces
K. zopfii K. zopfii K. zopfii
B+T NCIB 10495 NCIB 10499 NCIB 8603
River mud Cow faeces
K. zopfii Kurthia spp.
NCTC404 l NCIB 9878"
Meat
Garden soil Horse box straw Horse faeces Dung heap Pond water Calf pen soil Hen faeces
K. zopfii
B+T+P
NCTC 405
Pig faeces
Other
K22
Flavobacterium okeanokoites
strains
K24 K28 K45++, K47++ K48t-+, K49++ K60, K63 K70++ K81++
Antarctic peat Mince beef Antarctic peat
T+N B+T+P+N B+T+P+N
Hen faeces Cow faeces Pig faeces
B+T B+T+P+N B+T+P+N
Kurthia-like
B: T: N: P:
Biotin Thiamine Nicotinic acid Pantothenic acid
NCMB 1054
B+T
+ : When supplied with Casitone alone. + + : When supplied with Casitone + Casamino acids. All other strains required factors in Casamino acids alone. ". Type strain.
Vitamin Requirements of Kurthia
441
from K. zopfii and K. gibsonii in the numerical taxonomic study. The vitamin requirements of these 11 strains (Table 1) were also determined in an attempt to resolve further their taxonomic position. Materials and Methods All glassware and polypropylene containers were cleaned by techniques similar to those described by Owens and Keddie (1968). Nutritional test media were based on mineral base E (Min E, Owens and Keddie, 1969). Appropriate Bacto-yeast extract (Difco) or Bacto-vitarnin-free Cas amino acids (Difco) was added to give a final concentration of 1 gil. These media were sterilized by autoclaving at 121 DC for 20 min. All other components were filter-sterilized and added aseptically to the sterile media. Acetate (1 gil) was incorporated as carbon and energy source in all test media and Bacto-vitamin-frec Casitone (Difco, 1 gil) was added to some media. Vitamin mixtures were added as appropriate to give the following final concentrations: biotin, 2 flg/l; thiamine, 500 flg/l; pantothenic acid, 500 fIg/!; nicotinic acid, 500 flg/l. Previous studies in this laboratory have shown that these vitamins are the ones most commonly required by aerobic, asporogenous Gram-positive rods. Each complete medium was dispensed in 3 ml amounts into sterile, stainless steel-capped test tubes. The strains were maintained on yeast nutrient agar slopes (YNA) as described by Shaw and Keddie (1983). For each strain the first growth of a second subculture on a 5 ml YNA slope, usually after 18-24 h incubation at 25 DC, was used to prepare a just visibly turbid suspension in a 3 ml quantity of mineral base E with no nitrogen source (Min E-N, Owens and Keddie, 1969). Each tube of test medium was inoculated with one drop by Pasteur pipette of the suspension and then the tubes were incubated at 25°C in a sloped position on a reciprocating shaker set at ca. 130 cycles/min. Throughout the study, strains of known nutritional requirements were included to ensure that particular vitamin requirements were being demonstrated. Uninoculated tubes of nutritional test media were included to check for contamination. Inoculum viability was assessed from the amount of growth in the most complex medium investigated (medium 5 below). The following media were inoculated to divide the strains into broad nutritional groups: (1) Min E + acetate; (2) Min E + acetate + vitamin-free Casamino acids; (3) Min E + acetate + 4 vitamins mixture; (4) Min E + acetate + vitamin-free Cas amino acids + 4 vitamins mixture; (5) Min E + acetate + yeast extract. Growth was assessed visually each day until maximum turbidity was reached, or after 7 days incubation. The least complex medium which supported good growth gave the broad nutritional requirements of each strain tested. For strains which grew in medium 4 but not in media 1, 2 or 3 the specific vitamins required were determined by the single deletion technique. Three serial subcultures were made for each strain and when maximum growth was reached in the third subculture, it was diluted with an equal volume of glass distilled water and the absorbance measured in an EEL absorptiometer (Evans Electroselenium Ltd., Halstead, Essex) using a 604 filter. A vitamin was considered to be required when its omission from an otherwise nutritionally adequate, defined medium resulted in the absence of growth or only slight growth (giving an absorptiometer reading of 2.5 or less) compared with that in the complete, defined medium (giving an absorptiometer reading of 10.0 or more). The individual vitamin requirements of each strain were then checked by inoculation into the least complex medium which supported growth and into a series of media from which each of the vitamins in this medium was omitted in turn. Other experimental details are given above. Strains which grew only in medium 5 were inoculated into four further test media: medium 4 described above; medium 3 described above + vitamin-free Casitone; medium 4 + vitamin-free Casitone; medium 5 described above. Serial subcultures and absorptiometer readings were done as described above. The vitamin requirements of strains
442
S.Shaw and R. M. Keddie
which grew in medium 4 + vitamin-free Casitone were determined by the single deletion technique described above but with the addition of vitamin-free Casitone to each nutritional test medium. Results and Discussion Broad nutritional groups
The strains were divided into two groups by the initial screening method. Fiftyeight of the 69 strains grew in medium 4 which contained Min E + acetate + vitamin-free Casamino acids + 4 vitamins mixture, whereas the remaining 11 strains required additional factors supplied by yeast extract, later found to be satisfied by vitamin-free Casitone. Of these 11 strains, two (K8, K34) grew in a medium containing Min E + acetate + Casitone + 4 vitamins mixture while the remaining 9 strains (K4,K39, K45, K47, K48, K49, K58, K70, K81) grew only when the medium also contained Casamino acids. The requirements for factors in Casamino acids or Casitone were not investigated further but presumably they provided one or more of the following: (1) amino acids which would substitute for one or more vitamins required for their synthesis, or which would satisfy a requirement for one or more specific amino acids; (2) a carbon + energy source if acetate was not utilized; (3) a nitrogen source if ammonium sulphate was not utilized. In addition to the above factors, Casitone could also have satisfied a requirement for peptides (Habeeb, 1959a, b), or for amino acids such as tryptophan destroyed in the preparation of Casamino acids (Owens and Keddie, 1968). The requirement by some Kurthia strains for factors in Casamino acids in addition to Casitone is less easily explained. Perhaps for these strains certain amino acids are not freely available in Casitone or are supplied in too Iowa concentration. Individual vitamin requirements
The individual vitamin requirements (when supplied with vitamin-free Casamino acids and/or Casitone) of the 69 strains studied are listed in Table 1. Four patterns of requirements occurred; biotin + thiamine were required by 20 strains, biotin + thiamine + pantothenic acid by 41 strains, thiamine + nicotinic acid by one strain, and all 4 vitamins tested were required by seven strains. Taxonomic considerations The genus Kurthia. Both K. zopfii and K. gibsonii (Shaw and Keddie, 1983) were homogeneous with respect to their vitamin requirements. Thus, when supplied with vitamin-free Casamino acids and/or Casitone, all K. zopfii strains required biotin + thiamine + pantothenic acid while all K. gibsonii strains required biotin + thiamine only. The uniformity of the vitamin requirements within each of the two taxa and the difference in requirements between the two, supports the view that each represents a species. K. zopfii strains NCTC 404 and NCTC 405, and K. gibsonii NCIB 8603 (labelled K. zopfii) were only loosely attached to their respective clusters in the numerical taxonomic study of Shaw and Keddie (1983). However, the vitamin requirements of these strains did not differ from those of the other strains in their respective clusters thus providing additional evidence that they are members of the species
Vitamin Requirements of Kurthia
443
to which they were allocated. K. zop{ii strains NCTC 404 and NCTC 405 required factors both in Casitone and in Casamino acids for growth whereas most K. zopfii strains required factors in Casamino acids alone. However, strain K39, a K. zopfii strain whose position was not in question in the numerical taxonomic study, exhibited a similar requirement suggesting that this difference may not be very significant. The species descriptions given by Shaw and Keddie (1983) may now include the statements that when supplied with a suitable source of amino acids K. zopfi: requires biotin, thiamine and pantothenic acid and K. gibsonii requires biotin and thiamine. Kurthia-like strains. Eleven strains which conformed in most or all respects to the definition of Kurthia in Bergey's Manual (Keddie and Rogosa, 1974) were separated from the main Kurthia area in the numerical taxonomic study of Shaw and Keddie (1983). Studies of their vitamin requirements showed that most had requirements different from K. gibsonii and K. zopfii but otherwise contributed little to determining their taxonomic position. One feature of interest which emerged is that three strains (K45, K47, K48) isolated from Antarctic peat (Baker and Smith, 1972) which formed a tight cluster in the numerical taxonomic study also had the same vitamin requirements: all required biotin + thiamine + nicotinic acid + pantothenic acid when supplied with vitamin-free Cas amino acids and Casitone.
References Baker, ]. H., Smith, D. G.: The bacteria in Antarctic peat. J. appl, Bact. 35, 589-596 (1972) Habeeb, A.F.S.A.: A study of bacteriological media: the examination of Bacto-casitone.
J. Pharm. Pharmacol. 11, 157-162 (1959a)
Habeeb, A. F. S. A.: A study of bacteriological media: the examination of peptides in Bacto-
casitone. J. Pharm. Pharmacol. 11, 376-382 (1959b)
Keddie, R. M.: The genus Kurthia. In: The Prokaryotes (M. P. Starr, H. Stolp, H. G. Triiper, A. Ballouis, H. G. Schlegel, eds.) New York- Heidelberg- Berlin, Springer-Verlag 1981 Keddie, R. M., Rogosa, M.: Genus Kurthia. In: Bergey's manual of determinative bacteriology (R. E. Buchanan, N. E. Gibbons, eds.), 8th ed. Baltimore, Williams and Wilkins
1974
Owens, ]. D., Keddie, R. M.: A note on the vitamin requirements of some coryneform bac-
teria from soil and herbage. J. appl. Bact. 31, 344-348 (1968)
Owens, ]. D., Keddie, R. M.: The nitrogen nutrition of soil and herbage coryneform bac-
teria.
J. appl. Bact. 32, 338-347 (1969)
Shaw, S., Keddie, R. M.: A numerical taxonomic study of the genus Kurthia with a revised description of Kurthia zopfii and a description of Kurthia gibsonii sp. nov. System. Appl, Microbiol. 4, 253-276 (1983)
Dr. R. M. Keddie, Department of Microbiology, University of Reading, London Road, Reading, RG1 5AQ, England
Depart ment of Microbiology, University of Reading, Readin g RG1 5AQ, England
The Vitamin Requirements of Kurthia zopjii and Kurthia
gibsonii STEVEN SHAWl and RONALD M . KEDDIE
Received April 19, 1983
Summary T he vitam in requirements of 17 K. gibsonii mains, 41 K. zopfii strains and 11 presumptive Kurthia isolates which could not be assigned to either species, were determin ed. When supplied with Casa mino acids and /or Casito ne the K. gibsonii strains required bio tin + th iamin e for grow th whereas the K. ~opfii strai ns required biotin + th iam ine + pa ntothenic acid . Th e difference in their requirements pr ovides support for the existence of the two species within th e genus. Eight of rhe 11 pr esu mptive Kurthia isolates had vita min requ irement s different fro m bot h K. zopfii and K. gibsonii; their taxon omic position remained unr esolved.
Key words: Kurthia - Kurtbia zopfii - Kurthia gibsonii - Vitamin requirements T axonomy
Introduction The genus Kurthia was d escrib ed as monospecific in Bergey's M anual (Keddie and Rogosa, 1974) but based on the re sults of a numerical taxonomic study Shaw an d Keddie (1983) proposed th at a second species, K. gibsonii, sho uld be recognized. N o information is ava ilable on th e nutritional requirements of Kurthia spp. other th an tha t growth occurs only in co mplex media (Keddie and Rogosa, 1974; Keddie, 1981). Therefore in the present study the vitamin requirement s of 17 K. gibsonii and 41 K. zopfii strains (Table 1) studie d by Shaw and Keddie (1983) were dete rm ined. The aim s we re to find out if eac h species was hom ogeneou s in vitamin requirements and whether o r not a study of th e vitamin requ irements wo uld reveal further differen ces between th e two species . Shaw and Keddie (1983) also described 11 Kurthia-like strai ns wh ich confo rmed in mo st or all respects to the definition of Kurthia in Bergey's Manua l (Keddie and Rogosa, 1974), but which were distinct
1
Present address: Watney Mann & T ruman Brewers Ltd ., London SW14 8]D, England.
29 Systematic and Applied Microb iology. Vol. 4
440
S.Shaw and R.M.Keddie
Table 1. Vitamin requirements of the strains studied when supplied with Casamino acids and/or Casitone Species etc. (Shaw and
Laboratory strain number
Name or source
Strain number
K1 K2 K3 K6, K8+, K9, K12, K30, K50 K27, K69 K29 K31 K57 K68 K75, K79
Kurthia sp. Kurthia sp. Kurthia sp.
NCIB 9756 NCIB 9757 NCIB 9758"
Vitamins required
Keddie, 1983) K. gibsonii
K. zopfii
K4++ K5 K7, Kll, K13, K14, K15, K16, K17, K18, K19, K26, K32, K33, K34+, K54, K56, K84, K85, K86, K88 K35 K36 K37, K40 K38 K39++ K41, K42 K43, K44, K61 K65, K66, K71 K58++ K72, K74, K76, K78, K80
Meat Hen faeces
K. zopfii K. zopfii K. zopfii
B+T NCIB 10495 NCIB 10499 NCIB 8603
River mud Cow faeces
K. zopfii Kurthia spp.
NCTC404 l NCIB 9878"
Meat
Garden soil Horse box straw Horse faeces Dung heap Pond water Calf pen soil Hen faeces
K. zopfii
B+T+P
NCTC 405
Pig faeces
Other
K22
Flavobacterium okeanokoites
strains
K24 K28 K45++, K47++ K48t-+, K49++ K60, K63 K70++ K81++
Antarctic peat Mince beef Antarctic peat
T+N B+T+P+N B+T+P+N
Hen faeces Cow faeces Pig faeces
B+T B+T+P+N B+T+P+N
Kurthia-like
B: T: N: P:
Biotin Thiamine Nicotinic acid Pantothenic acid
NCMB 1054
B+T
+ : When supplied with Casitone alone. + + : When supplied with Casitone + Casamino acids. All other strains required factors in Casamino acids alone. ". Type strain.
Vitamin Requirements of Kurthia
441
from K. zopfii and K. gibsonii in the numerical taxonomic study. The vitamin requirements of these 11 strains (Table 1) were also determined in an attempt to resolve further their taxonomic position. Materials and Methods All glassware and polypropylene containers were cleaned by techniques similar to those described by Owens and Keddie (1968). Nutritional test media were based on mineral base E (Min E, Owens and Keddie, 1969). Appropriate Bacto-yeast extract (Difco) or Bacto-vitarnin-free Cas amino acids (Difco) was added to give a final concentration of 1 gil. These media were sterilized by autoclaving at 121 DC for 20 min. All other components were filter-sterilized and added aseptically to the sterile media. Acetate (1 gil) was incorporated as carbon and energy source in all test media and Bacto-vitamin-frec Casitone (Difco, 1 gil) was added to some media. Vitamin mixtures were added as appropriate to give the following final concentrations: biotin, 2 flg/l; thiamine, 500 flg/l; pantothenic acid, 500 fIg/!; nicotinic acid, 500 flg/l. Previous studies in this laboratory have shown that these vitamins are the ones most commonly required by aerobic, asporogenous Gram-positive rods. Each complete medium was dispensed in 3 ml amounts into sterile, stainless steel-capped test tubes. The strains were maintained on yeast nutrient agar slopes (YNA) as described by Shaw and Keddie (1983). For each strain the first growth of a second subculture on a 5 ml YNA slope, usually after 18-24 h incubation at 25 DC, was used to prepare a just visibly turbid suspension in a 3 ml quantity of mineral base E with no nitrogen source (Min E-N, Owens and Keddie, 1969). Each tube of test medium was inoculated with one drop by Pasteur pipette of the suspension and then the tubes were incubated at 25°C in a sloped position on a reciprocating shaker set at ca. 130 cycles/min. Throughout the study, strains of known nutritional requirements were included to ensure that particular vitamin requirements were being demonstrated. Uninoculated tubes of nutritional test media were included to check for contamination. Inoculum viability was assessed from the amount of growth in the most complex medium investigated (medium 5 below). The following media were inoculated to divide the strains into broad nutritional groups: (1) Min E + acetate; (2) Min E + acetate + vitamin-free Casamino acids; (3) Min E + acetate + 4 vitamins mixture; (4) Min E + acetate + vitamin-free Cas amino acids + 4 vitamins mixture; (5) Min E + acetate + yeast extract. Growth was assessed visually each day until maximum turbidity was reached, or after 7 days incubation. The least complex medium which supported good growth gave the broad nutritional requirements of each strain tested. For strains which grew in medium 4 but not in media 1, 2 or 3 the specific vitamins required were determined by the single deletion technique. Three serial subcultures were made for each strain and when maximum growth was reached in the third subculture, it was diluted with an equal volume of glass distilled water and the absorbance measured in an EEL absorptiometer (Evans Electroselenium Ltd., Halstead, Essex) using a 604 filter. A vitamin was considered to be required when its omission from an otherwise nutritionally adequate, defined medium resulted in the absence of growth or only slight growth (giving an absorptiometer reading of 2.5 or less) compared with that in the complete, defined medium (giving an absorptiometer reading of 10.0 or more). The individual vitamin requirements of each strain were then checked by inoculation into the least complex medium which supported growth and into a series of media from which each of the vitamins in this medium was omitted in turn. Other experimental details are given above. Strains which grew only in medium 5 were inoculated into four further test media: medium 4 described above; medium 3 described above + vitamin-free Casitone; medium 4 + vitamin-free Casitone; medium 5 described above. Serial subcultures and absorptiometer readings were done as described above. The vitamin requirements of strains
442
S.Shaw and R. M. Keddie
which grew in medium 4 + vitamin-free Casitone were determined by the single deletion technique described above but with the addition of vitamin-free Casitone to each nutritional test medium. Results and Discussion Broad nutritional groups
The strains were divided into two groups by the initial screening method. Fiftyeight of the 69 strains grew in medium 4 which contained Min E + acetate + vitamin-free Casamino acids + 4 vitamins mixture, whereas the remaining 11 strains required additional factors supplied by yeast extract, later found to be satisfied by vitamin-free Casitone. Of these 11 strains, two (K8, K34) grew in a medium containing Min E + acetate + Casitone + 4 vitamins mixture while the remaining 9 strains (K4,K39, K45, K47, K48, K49, K58, K70, K81) grew only when the medium also contained Casamino acids. The requirements for factors in Casamino acids or Casitone were not investigated further but presumably they provided one or more of the following: (1) amino acids which would substitute for one or more vitamins required for their synthesis, or which would satisfy a requirement for one or more specific amino acids; (2) a carbon + energy source if acetate was not utilized; (3) a nitrogen source if ammonium sulphate was not utilized. In addition to the above factors, Casitone could also have satisfied a requirement for peptides (Habeeb, 1959a, b), or for amino acids such as tryptophan destroyed in the preparation of Casamino acids (Owens and Keddie, 1968). The requirement by some Kurthia strains for factors in Casamino acids in addition to Casitone is less easily explained. Perhaps for these strains certain amino acids are not freely available in Casitone or are supplied in too Iowa concentration. Individual vitamin requirements
The individual vitamin requirements (when supplied with vitamin-free Casamino acids and/or Casitone) of the 69 strains studied are listed in Table 1. Four patterns of requirements occurred; biotin + thiamine were required by 20 strains, biotin + thiamine + pantothenic acid by 41 strains, thiamine + nicotinic acid by one strain, and all 4 vitamins tested were required by seven strains. Taxonomic considerations The genus Kurthia. Both K. zopfii and K. gibsonii (Shaw and Keddie, 1983) were homogeneous with respect to their vitamin requirements. Thus, when supplied with vitamin-free Casamino acids and/or Casitone, all K. zopfii strains required biotin + thiamine + pantothenic acid while all K. gibsonii strains required biotin + thiamine only. The uniformity of the vitamin requirements within each of the two taxa and the difference in requirements between the two, supports the view that each represents a species. K. zopfii strains NCTC 404 and NCTC 405, and K. gibsonii NCIB 8603 (labelled K. zopfii) were only loosely attached to their respective clusters in the numerical taxonomic study of Shaw and Keddie (1983). However, the vitamin requirements of these strains did not differ from those of the other strains in their respective clusters thus providing additional evidence that they are members of the species
Vitamin Requirements of Kurthia
443
to which they were allocated. K. zop{ii strains NCTC 404 and NCTC 405 required factors both in Casitone and in Casamino acids for growth whereas most K. zopfii strains required factors in Casamino acids alone. However, strain K39, a K. zopfii strain whose position was not in question in the numerical taxonomic study, exhibited a similar requirement suggesting that this difference may not be very significant. The species descriptions given by Shaw and Keddie (1983) may now include the statements that when supplied with a suitable source of amino acids K. zopfi: requires biotin, thiamine and pantothenic acid and K. gibsonii requires biotin and thiamine. Kurthia-like strains. Eleven strains which conformed in most or all respects to the definition of Kurthia in Bergey's Manual (Keddie and Rogosa, 1974) were separated from the main Kurthia area in the numerical taxonomic study of Shaw and Keddie (1983). Studies of their vitamin requirements showed that most had requirements different from K. gibsonii and K. zopfii but otherwise contributed little to determining their taxonomic position. One feature of interest which emerged is that three strains (K45, K47, K48) isolated from Antarctic peat (Baker and Smith, 1972) which formed a tight cluster in the numerical taxonomic study also had the same vitamin requirements: all required biotin + thiamine + nicotinic acid + pantothenic acid when supplied with vitamin-free Cas amino acids and Casitone.
References Baker, ]. H., Smith, D. G.: The bacteria in Antarctic peat. J. appl, Bact. 35, 589-596 (1972) Habeeb, A.F.S.A.: A study of bacteriological media: the examination of Bacto-casitone.
J. Pharm. Pharmacol. 11, 157-162 (1959a)
Habeeb, A. F. S. A.: A study of bacteriological media: the examination of peptides in Bacto-
casitone. J. Pharm. Pharmacol. 11, 376-382 (1959b)
Keddie, R. M.: The genus Kurthia. In: The Prokaryotes (M. P. Starr, H. Stolp, H. G. Triiper, A. Ballouis, H. G. Schlegel, eds.) New York- Heidelberg- Berlin, Springer-Verlag 1981 Keddie, R. M., Rogosa, M.: Genus Kurthia. In: Bergey's manual of determinative bacteriology (R. E. Buchanan, N. E. Gibbons, eds.), 8th ed. Baltimore, Williams and Wilkins
1974
Owens, ]. D., Keddie, R. M.: A note on the vitamin requirements of some coryneform bac-
teria from soil and herbage. J. appl. Bact. 31, 344-348 (1968)
Owens, ]. D., Keddie, R. M.: The nitrogen nutrition of soil and herbage coryneform bac-
teria.
J. appl. Bact. 32, 338-347 (1969)
Shaw, S., Keddie, R. M.: A numerical taxonomic study of the genus Kurthia with a revised description of Kurthia zopfii and a description of Kurthia gibsonii sp. nov. System. Appl, Microbiol. 4, 253-276 (1983)
Dr. R. M. Keddie, Department of Microbiology, University of Reading, London Road, Reading, RG1 5AQ, England