Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Induction kinetics of a conditional pH stress response system in
  Escherichia coli   The analysis of stress response systems in microorganisms can reveal
molecular strategies for regulatory control and adaptation. Here, we focus on
the Cad module, a subsystem of E. coli's response to acidic stress, which is
conditionally activated at low pH only when lysine is available. When
expressed, the Cad system counteracts the elevated H+ concentration by
converting lysine to cadaverine under the consumption of H+, and exporting
cadaverine in exchange for external lysine. Surprisingly, the cad operon
displays a transient response, even when the conditions for its induction
persist. To quantitatively characterize the regulation of the Cad module, we
have experimentally recorded and theoretically modeled the dynamics of
important system variables. We establish a quantitative model that adequately
describes and predicts the transient expression behavior for various initial
conditions. Our quantitative analysis of the Cad system supports a negative
feedback by external cadaverine as the origin of the transient response.
Furthermore, the analysis puts causal constraints on the precise mechanism of
signal transduction via the regulatory protein CadC.

2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys