Biology Reference
In-Depth Information
Chart 2:
AI 3-oxo-C6-HSL outside the cell in blue, inside the cell in red.
lux
operon-bioluminiscence (purple), LuxR1 (blue)
and LuxR2 (green) in the quorum sensing system. The
y
-axis represents the abstract concentration of the elements. The
x
-axis
represents the simulation steps to perform a fire state within the Petri net. (Colours are visible in the online version of the article
at
www.iospress.nl
.)
Chart 3:
The different gene activation mechanisms by LuxR1/LuxR2 and LitR. The secretion, the mobility, the biofilm
formation and other operons in blue. The concentration of the
lux
operon-bioluminiscence in red. (Colours are visible in the
online version of the article at
www.iospress.nl
.)
one of LuxR1/LuxR2 within the system. This behavior senses the biological characteristics. The
lux
operon-bioluminiscence expression can only increase as long as the LuxR1 and LuxR2 are both activated.
Based on the aforementioned Petri net model, we used a reduced Petri net representation due to the
visibility of the networks (Fig. 7). The resulting Petri net contains the fundamental elements of the
quorum sensing system and can be used for modeling a single cell or an entire population of cells. In the
following steps, this Petri net as a combined network serves as a basis for the cell-to-cell communication
processes within bacteria colonies. For simulation processes we made use of the detailed Petri net model
indicated in Fig. 6.
Based on the developed Petri net for the quorum sensing network, we are attempting to find the most
suitable Petri net representations for the modeling of cell-to-cell communication processes. The major
idea behind our work is to combine existing fundamental Petri net concepts. Therefore, we defined an
elementary cell representation, which is presented in Fig. 7. This model is used for the demonstration of
the communication processes, but is replaced by the detailed Petri net indicated in Fig. 6 for simulation
purposes.
The simplest connection of cells and its environment is without respect to space. In the following
model all cells are connected to a global place that represents the autoinducer in the environment and
is affected by diffusion as shown in Fig. 8. In this model, the concentration of produced autoinducer
