-
- Posted Wednesday November 26, 2014
TGen-Luxembourg team conducts unprecedented analysis of microbial ecosystem
Research published in Nature Communications has implications for protecting environment, energy and human health
FLAGSTAFF, Ariz. - Nov. 26, 2014 - An
international team of scientists from the Translational
Genomics Research Institute (TGen) and The Luxembourg Centre
for Systems Biomedicine (LCSB) have completed a first-of-its-kind
microbial analysis of a biological wastewater treatment plant that
has broad implications for protecting the environment, energy
recovery and human health.
The study, published Nov. 26 in the scientific journal Nature
Communications (DOI: 10.1038/ncomm6603), describes in unprecedented
detail the complex relationships within a model ecosystem.
The study focused on biofuel molecules, lipids, which are
naturally accumulated by microbial mats and floated on top of
wastewater. This is "free energy" as lipids can be converted into
diesel fuel.
"Bacterial communities are everywhere, and understanding how they
interact is critical to industry, agriculture, the environment and
human health," said Dr. Paul Keim, Director of TGen's Pathogen
Genomics Division, noting both the academic achievement and the
applied implications of these research efforts.
"Basic principles of microbial community function can be
established in one setting and then used to generate hypotheses and
models applicable to all," said Dr. Keim, who also is a Regents
Professor of Microbiology at Northern Arizona University
(NAU).
The study's findings corroborate and unify various ecological
concepts that have been primarily formulated based on observations
in macrobiotic systems such as forests, rivers and oceans, which
cannot be experimentally investigated in depth because of the sheer
size of these biotopes.
For their analyses of the treatment plant ecosystem, the
researchers employed Systems Biology methods. Wastewater destined
for treatment comprises energy-rich substrates including fats,
proteins, carbohydrates and many other substances that serve as
nutrients for the resident bacteria. Every wastewater treatment
plant is therefore a complex ecosystem. Countless bacterial species
adapt to the living conditions in the water, compete for resources
and each find a niche in which they can best survive.
"The techniques developed at LCSB allow us now to unravel these
processes very precisely at the molecular level," says Dr. Emilie
Muller of LCSB and the study's first author.
The basis for this are the so-called "omics" - genomics,
transcriptomics, proteomics and metabolomics - combined with new
bioinformatic methods for integrated data analysis.
"With these, we can determine from samples which organisms are
living in the treatment plant, and what their population sizes,
genetic make-up, activities and material turnovers are like.
Therefore, there is no longer any need to study bacteria separately
in pure cultures," Muller said. "Based on this, we can ultimately
model the material flows in the 'treatment plant' ecosystem and
describe, for example, which bacterial species will use and consume
which substrate and to what degree."
The TGen-LCSB team wants to go further than simply modeling the
wastewater treatment plant ecology. Their study aimed to understand
what factors determine the species composition and accordingly the
balance in the ecosystem.
One species of bacteria grabbed the researchers' attention:
Microthrix parvicella, whose genome sequence they first decrypted
two years ago. This bacterium can absorb and store an especially
large amount of lipids. In winter, up to 50 percent of all bacteria
on the surface of treatment tanks belong to this species. This is
rather astonishing, given that the amount of lipids in the
wastewater is rather low in winter, and Microthrix actually has
unfavorable living conditions during that season.
The study found that Microthrix possesses 28 copies of the gene
that is chiefly responsible for lipid uptake. The amplification of
this gene illustrates how important lipid accumulation is for this
organism and its associated community.
"Microthrix is what ecologists call a generalist. The organism can
adapt to very many living conditions and thereby dominate the
highly fluctuating wastewater treatment plant ecosystem," said Dr.
Paul Wilmes, head of the LCSB group "Ecosystems Biology" and the
study's senior author.
This is helped, among other things, by the 28 genes for lipid
uptake, Wilmes said: "Each copy of the gene is a little different
from the others. If the living conditions change, say when the
temperature drops or the lipid composition changes, then a
different lipid uptake gene adapted to that condition sets in. That
way, Microthrix can survive in many different environments."
The study team's translational aim is to boost the activity of
Microthrix to remove as many lipids from the wastewater as
possible. The lipids from wastewater stored in the bacteria are a
renewable energy source because they can be easily converted into
biodiesel.
Dr. Lance Price, a TGen team member and study co-author, said such
ecosystems research has important medical implications, as well:
"The human microbiome is a similar community of microbes. It
dominates many tissues and organ systems through microbiome
metabolism, interaction with human cells, and its ability to
protect us against pathogens. The systematic analysis of the waste
water communities will lead to insights for human health as well as
translational applications in sustainable energy."
# # #
About TGen
Translational Genomics Research Institute (TGen) is a Phoenix,
Arizona-based non-profit organization dedicated to conducting
groundbreaking research with life changing results. TGen is focused
on helping patients with cancer, neurological disorders and
diabetes, through cutting edge translational research (the process
of rapidly moving research towards patient benefit). TGen
physicians and scientists work to unravel the genetic components of
both common and rare complex diseases in adults and children.
Working with collaborators in the scientific and medical
communities literally worldwide, TGen makes a substantial
contribution to help our patients through efficiency and
effectiveness of the translational process. For more information,
visit:www.tgen.org.
Press Contact:
Steve Yozwiak
TGen Senior Science Writer
602-343-8704
[email protected]