'Simple' bacteria found to organize in elaborate patterns

Date:
January 6, 2022
Source:
University of California - San Diego
Summary:
Researchers have discovered that biofilms, bacterial communities
found throughout the living world, are far more advanced than
previously believed. Scientists found that biofilm cells are
organized in elaborate patterns, a feature that previously only
had been associated with higher- level organisms such as plants
and animals.



FULL STORY ==========================================================================
Over the past several years, research from University of California
San Diego biologist Gu"rol Su"el's laboratory has uncovered a series of remarkable features exhibited by clusters of bacteria that live together
in communities known as biofilms.


========================================================================== Biofilms are prevalent in the living world, inhabiting sewer pipes,
kitchen counters and even the surface of our teeth. A previous research
study demonstrated that these biofilms employ sophisticated systems
to communicate with one another, while another proved biofilms have a
robust capacity for memory.

Su"el's laboratory, along with researchers at Stanford University
and the Universitat Pompeu Fabra in Spain, has now found a feature
of biofilms that reveal these communities as far more advanced than
previously believed.

Biological Sciences graduate student Kwang-Tao Chou, former Biological
Sciences graduate student Daisy Lee, Su"el and their colleagues discovered
that biofilm cells are organized in elaborate patterns, a feature that previously only had been associated with higher-level organisms such
as plants and animals. The findings, which describe the culmination of
eight years of research, are published Jan. 6 in the journal Cell.

"We are seeing that biofilms are much more sophisticated than we thought,"
said Su"el, a UC San Diego professor in the Division of Biological
Sciences' Section of Molecular Biology, with affiliations in the San
Diego Center for Systems Biology, BioCircuits Institute and Center
for Microbiome Innovation. "From a biological perspective our results
suggest that the concept of cell patterning during development is far
more ancient than previously thought. Apparently, the ability of cells to segment themselves in space and time did not just emerge with plants and vertebrates, but may go back over a billion years." Biofilm communities
are made up of cells of different types. Scientists previously had not
thought that these disparate cells could be organized into regulated
complex patterns. For the new study, the scientists developed experiments
and a mathematical model that revealed the genetic basis for a "clock and wavefront" mechanism, previously only seen in highly evolved organisms
ranging from plants to fruit flies to humans. As the biofilm expands and consumes nutrients, a "wave" of nutrient depletion moves across cells
within the bacterial community and freezes a molecular clock inside each
cell at a specific time and position, creating an intricate composite
pattern of repeating segments of distinct cell types.

The breakthrough for the researchers was the ability to identify
the genetic circuit underlying the biofilm's ability to generate the
biofilm community-wide concentric rings of gene expression patterns. The researchers were then able to model predictions showing that biofilms
could inherently generate many segments.

"Our discovery demonstrates that bacterial biofilms employ a developmental patterning mechanism hitherto believed to be exclusive to vertebrates
and plant systems," the authors note in the Cell paper.

The study's findings offer implications for a multitude of research areas.

Because biofilms are pervasive in our lives, they are of interest in applications ranging from medicine to the food industry and even the
military.

Biofilms as systems with the capability to test how simple cell
systems can organize themselves into complex patterns could be useful
in developmental biology to investigate specific aspects of the clock
and waveform mechanism that functions in vertebrates, as one example.

"We can see that bacterial communities are not just globs of cells,"
said Su"el, who envisions research collaborations offering bacteria as
new paradigms for studying developmental patterns. "Having a bacterial
system allows us to provide some answers that are difficult to obtain in vertebrate and plant systems because bacteria offer more experimentally accessible systems that could provide new insights for the field of development." Coauthors of the paper include: Kwang-Tao Chou (UC San
Diego graduate student), Dong-yeon Lee (former UC San Diego graduate
student, now a postdoctoral scholar at Stanford University), Jian-geng
Chiou (UC San Diego postdoctoral scholar), Leticia Galera-Laporta (UC
San Diego postdoctoral scholar), San Ly (former UC San Diego researcher),
Jordi Garcia-Ojalvo (Universitat Pompeu Fabra Professor) and Gu"rol Su"el
(UC San Diego Professor).

========================================================================== Story Source: Materials provided by
University_of_California_-_San_Diego. Original written by Mario
Aguilera. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kwang-Tao Chou, Dong-yeon D. Lee, Jian-geng Chiou, Leticia Galera-
Laporta, San Ly, Jordi Garcia-Ojalvo, Gu"rol M. Su"el. A
segmentation clock patterns cellular differentiation in a bacterial
biofilm. Cell, 2022; 185 (1): 145 DOI: 10.1016/j.cell.2021.12.001 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220106111601.htm

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