241 research outputs found
Communication and Stochastic Processes in Some Bacterial Populations: Significance for Membrane Computing
Intercellular communication between bacterial cells belonging to the same
population is well documented in Microbiology, sporulation and cannibalism in B. Subtilis
and genetic competence and fratricide in S. pneumoniae being deeply studied in the
last years. The investigation of individual cell behavior has revealed that populations of
these bacteria sometimes bifurcate into phenotypically distinct, but genetically identical,
subpopulations by random switching mechanisms. The probabilistic nature of the random
switching mechanisms, the occurrence of some biochemical processes related to it at
plasma membrane and the need to study the processes at the level of each individual cell
make intercellular communication and stochastic processes very suitable to be modeled
by P systems
On Modelling Ion Fluxes Across Biological Membranes with P Systems
In this report we address the challenge of using P systems to integrate at
the whole cell level both active and passive transport of different ions, done by different
types of membrane transport proteins which work simultaneously and concurrently
New Proposals for the Formalization of Membrane Proteins
This paper presents three new proposals to take advantage, in the
framework of P systems, from proteins acting in bacteria. One attempt aims
to focus on the transport protein that act as a logic AND gate at the cell
membrane. The multiplicity of type of transporters involved in maintaining
osmotic pressure within physiological values, both at short and long term level
are also presented, as an example of parallelism occurring in living cell. Finally,
the change of enzyme activity by reversible aggregation could be important for
P systems as a new rule to follow, and process to model
Some Notes on the Interplay Between P Systems and Chemotaxis in Bacteria
We describe some chemotactic behaviors of bacteria, that is, their movement
response to changes in the environment, and the underlying molecular mechanisms. We
outline how such processes could be linked to membrane computing, by taking inspiration
from them for new type of rules or new features to be introduced in P systems, as well as
by considering how the application of recent P system-based models can produce relevant
results for the description and the analysis of chemotaxis processes
Computing Using Signals: From Cells to P Systems
In cell biology one of the fundamental topic is the study of how
biological signals are managed by cells. Signals can arise from inside the cell
or from the external environment and the correct answer to certain signals is
essential for bacteria to survive in a certain environment. Starting from these
biological motivations we consider a model of P systems where the computa-
tion is controlled by signals which move across the regions. In particular, we
consider Signals-Based P systems where the symbol-objects cannot be moved
and the rules can be activated/inactivated using a ¯nite number of signals
(signal-promoters) moved across the membranes; di®erently from standard P
systems using promoters, in our case promoters cannot be created during the
computation. After discussing the biological motivations we show how this
model becomes universal when it uses one catalyst, and a bounded number of
signal-promoters
A Biological Perspective on Sorting with P Systems
The aim of this contribution is to argue that the processes occurring in biological
membranes in bacteria are also important as natural examples of communication
between membranes, which, in the formal framework of P systems, leads (among other
things) to simulations of sorting operations
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