Prokaryotes
Microbes
Here
we
shall
consider
in
brief
prokaryotes
other
than
eubacteria.
These
are
chiefly
archaebacteria,
mollicutes,
(mycoplasmas
or
PPLO),
L-forms,
mycobacteria,
myxobacteria,
rickettsiae
and
chlamydiae.
Archaebacteria
These
bacteria
differ
from
true
bacteria
(eubacteria)
in
respect
of
organisation
and
chemical
composition
of
their
cell
wall
and
cell
membrane.
Their
16s
rRNA
molecules
also
differ
from
other
bacteria
and
ribosomes
are
insensitive
to
chloramphenicol.
They
are
also
unique
in
inhabiting
extreme
environments.
Such
physiological
features
coupled
with
morphological
and
structural
differences
make
them
distinct
from
true
bacteria.
They
appear
to
be
primitive
bacteria
and
erectcd
to
the
status
of
a
kingdom,
distantly
related
to
other
prokaryotes.
They
include
the
methanogens
of
anaerobic
muds;
the
extreme
red
halophiles;
the
salt
loving
bacteria
of
saturated
brine
and
salted
fish;
and
the
thermoacidophiles,
found
in
hot
sulphur
spring
or
smouldering
coal
wastes.
It
is
suggested
that
they
represent
a
very
ancient
lineage
whieh
diverged
from
the
eubacteria
very
early
in
evolutionary
process,
and
have
survived
only
in
these
specialised
ecological
niches.
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