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An entire class of organisms has been all but forgotten in the global
discussions on preserving biodiversity, grumble those who work with them.
This month, an international group of microbiologists will set out their
strategy for identifying and culturing rare and elusive bacteria, and preserving
environments where unique bacteria flourish

The group is calling for more funding to expand collections of cultured
microorganisms and databases, develop new techniques for culturing ‘finicky’
strains, and launch massive screening programmes for bacteria with medicinal
properties or other useful characteristics

‘The problem with bacteria is that they are not warm and fuzzy,’ says
David Boone, an environmental microbiologist from the Oregon Graduate Institute
of Science and Technology.

Between 1 and 10 per cent of the world’s bacteria have been identified.
So little is known about most of the microbial world that no one has ever
documented the extinction of a bacterium. ‘The consensus is that it seems
likely that there have been extinctions of bacterial species caused by the
activity of man,’ says Boone

One strategy for saving unique strains of bacteria may be to preserve
the extreme habitats where some of the most highly specialised types of
microbes have evolved, such as hot springs, brine lakes and frozen tundra.
‘If any organism is adapted to live at these extremes it is likely to be
a microorganism,’ says Jim Tiedje, director of the Center for Microbial
Ecology at Michigan State University. But he also points out that there
are unidentified bacteria in common habitats such as soil and water that
have simply eluded microbe hunters, and which may be just as interesting.
‘The microorganisms we know about are simply the ones that are easy to
isolate and culture,’ he says

Boone studies the methane-producing bacteria known as methanogens that
live in hypersaline lakes such as Oregon’s Alkali Lake. ‘A given lake could
be home to a species of methanogen not found any-where else in the world,’
he says. ‘If we can foresee that an environment like that is going to be
altered significantly, it could be that we should get the bacteria into
culture so that we can make use of them in the future.’

The most celebrated case of a highly specialised bacterium that proved
extremely useful is Thermus aquaticus, or taq, a bacterium that thrives
in the boiling water of hot springs. An enzyme from taq is the catalyst
for the polymerase chain reaction, a method of producing millions of copies
of any DNA sequence. The reaction requires high temperatures

‘There’s a tremendous gene pool out there that can be utilised in biotechnology
and other industries,’ says Robert Gherna, a bacteriologist at the American
Type Culture Collection in Rockville, Maryland, which houses the world’s
most comprehensive collection of bacteria

Another category of bacteria that could quietly disappear are those
living in association with endangered plants or animals. For instance, many
animals harbour symbiotic bacteria in their intestines. Some of these bac-teria
may exist only in one species, and if that becomes extinct, so do the bacteria

With plants and animals, a biologist armed only with a camera and notebook
can identify new species. But microbiologists now rely on molecular techniques
such as gene probes in their quest to document the diversity of bacteria.
They have begun to sequence and catalogue portions of ribosomal RNA in order
to identify new strains

‘Since many of the bacteria look the same to us, we know far less about
them than we do about more complex organisms,’ says Tiedje.