A History of Iron Metabolism in the Mycobacteria - Iron Acquisition by the Genus Mycobacterium - page 21

Table 2.2 Occurrence of mycobactins in Mycobacterium and related species a
Species in which mycobactin
has been found in all strains
examined

Mycobacterium : M. aurum, M. avium b , M. bovis BCG,
M.chelonae, M. chitae, M. diernhoferi, M. duvali, M.
farcinogenes, M. flavescens, M. fortuitum, M. gadium,
M. gordonae, M. gallinarum, M. intracellulare, M.
kansasii, M. marinum, M. neoaurum, M. nonchromog-
enicum, M. peregrinum, M. phlei, M. scrofulaceum, M.
senegalense, M. smegmatis, M. szulgai, M. terrae, M.
trivale, M. tuberculosis, plus unspeciated species termed
“Armadillo-derived mycobacteria (ADM)”.
Nocardia : N. asteroides, N. brasilienses, N. caviae, N.
farcinica
Rhodococcus : R. bronchialis, R. rubropertinctus, R. terrae

Species in which mycobactin
has been found in low
(<0.1 %) concentration or is
absent in some strains

M. parafortuitum, M. thermoresistible, M. vaccae

Mycobacterium : “M. kanazawa” c , “ M. komossense ” c , M.
paratuberculosis d
Rhodococcus : R. coprophilus, R. equi, R. erythropolis, R.
Luteus, R. maris, R. rhodnii, R. rhodochrous, R. ruber

Species in which mycobactin
has not been found

a Data from [ 26 , 54 - 57 , 59 , 60 , 71 ]
b A few strains are dependent upon mycobactin for growth
c May not be a true Mycobacterium
d One strain (adapted to laboratory growth) produces mycobactin J [ 64 , 66 ]

paratuberculosis of that had lost their original dependency on mycobactin and
could now produce it themselves. This suggested a taxonomic similarity between
M. paratuberculosis and the MIAS complex of mycobacteria and this indeed has
now been confirmed by more conventional taxonomic methods [ 65 ]. M. para-
tuberculosis , having started life as Mycobacterium enteriditis chronicae pseu-
dotuberculosae bovis , Johne, or Johne's bacillus for short, and then becoming
M. johnei , is now re-named as M. avium subsp. paratuberculosis .
Barclay et al. [ 64 ] found that mycobactin Av differed from the other mycobac-
tins in having two long lipophilic side-chains (Fig. 2.4 ), one at the usual R 1 posi-
tion and the second one of about 10 carbons in length at the R 4 position. They also
showed that the mycobactins from M. tuberculosis, M. bovis and M. africanum ,
were identical molecules and therefore could all be named as mycobactin T.
A mycobactin from M . paratuberculosis , but of slightly different structure to
that isolated by Barclay et al. [ 64 ], had been isolated and identified 2 years earlier
by Richard Merkal [ 66 , 67 ]. Again this was being produced by a strain that was
initially mycobactin-dependent for growth but had subsequently reverted. This was
named as mycobactin J (Fig. 2.4 ) but it was more like the conventional mycobac-
tins in having just a single alkyl chain at the R1 position. The absolute configura-
tion of the structure of mycobactin J was subsequently confirmed by Schwartz and
De Voss [ 68 ]. Barclay et al. [ 64 ], having kindly been sent a sample of mycobactin
J and also the production organism, M. paratuberculosis strain NADC 18 (now