A. Quentmeier et Cg. Friedrich, TRANSFER AND EXPRESSION OF DEGRADATIVE AND ANTIBIOTIC-RESISTANCE PLASMIDS IN ACIDOPHILIC BACTERIA, Applied and environmental microbiology, 60(3), 1994, pp. 973-978
The genetic accessibility of selected acidophilic bacteria was investi
gated to evaluate their applicability to degrading pollutants in acidi
c environments. The IncP1 antibiotic resistance plasmids RP4 and pVK10
1 and the phenol degradation-encoding plasmid pPGH11 were transferred
from neutrophilic bacteria into the extreme acidophilic eubacterium Ac
idiphilium cryptum at frequencies of 1.8 x 10(-2) to 9.8 x 10(-4) tran
sconjugants per recipient cell. The IncQ antibiotic resistance plasmid
pSUP106 was mobilizable to A. cryptum by triparental matings at a fre
quency of 10(-5) transconjugants per recipient cell. In the transconju
gants, antibiotic resistances and the ability to degrade phenol were e
xpressed. A. cryptum AC6 (pPGH11) grew with 2.5 mM phenol at a doublin
g time of 12 h and a yield of 0.52 g (dry cell weight) per g of phenol
. A. cryptum harbored five native plasmids of 255 to 6.3 kb in size. P
lasmids RP4 and pVK101 were transferred from Escherichia coli into Aci
dobacterium capsulatum at frequencies of 10(-3) and 2.3 X 10(-4) and t
o the facultative autotroph Thiobacillus acidophilus at frequencies of
1.1 x 10(-5) and 2.9 x 10(-6) transconjugants per recipient cell, res
pectively. Plasmid pPGH11 could not be transferred into the latter str
ains. T. acidophilus wild type contained six so far cryptic plasmids o
f 220 to 5 kb.