234
D. Lloyd
Continuous monitoring of dissolved gases (O 2 , CO 2 and H 2 S, [96] by a submerged
probe, using membrane inlet mass spectrometry proved revelatory, especially when
employed in conjunction with intracellular redox state readout (NADPH, and flavins,
[17]. Transcriptional analyses using microarrays have revealed a global dynamic
architecture [18, 70, 71, 73], and that with respect to gene expression, the dominant
period is not the cell budding cycle (90–120 min), but more commonly the ~40 min
sub-multiple of that cycle period. Furthermore, wavelet analysis revealed genomewide oscillations in expression mirroring the 40 min respiratory oscillations in the self
synchronized continuous culture [72]. Two temporal clusters (4,679 of 5,329) were
maximally expressed in the reductive phase of the ~40-min cycle, and the third cluster
(650) in the respiratory stage [74]. Thus maximal expression of the gene super-cluster
important in respiration is functionally expressed oppositely in the cycle from those
genes known to be involved in reductive functions. The transcriptional cycle gates
synchronous bursts of DNA replication in a constant fraction of the population at
40 min intervals. It was also suggested [74], that the separation of DNA replication
into the reductive part of the ~40 min cycle represents an evolutionary important
mechanism for the obviation of oxidative damage (e.g. by reactive species derived
from partial reductive reactions of O 2 .
More than 1600 oscillating metabolites [2, 126, 129, 146] reveal coordination
with metabolic functions, organelle elaboration and function, and the cell division
cycle. Redox control is central in the cellular network and implicit to its rhythmicity
[129], and also to transcriptional processes and chromosome dynamics [2, 111, 112].
The detailed chronology of these coordinated research topics by collaborating
groups has been reviewed [1, 86, 104].
14.1.11 Non-linear Dynamics of the Self-synchronous
Culture: Chaos and Fractals
May [119] has written: ‘First-order difference equations arise in many contexts in
the biological, economic and social sciences. Such equations, even though simple
and deterministic, can exhibit a surprising array of dynamical behaviour, from stable
points, to a bifurcating hierarchy of stable cycles, to apparently random fluctuations.
There are consequently many fascinating problems, some concerned with delicate
mathematical aspects of the fine structure of the trajectories, and some concerned
with the practical implications and applications of the bizarre behaviour exhibited
by the simplest of discrete time, nonlinear systems, such as Eq. (14.1).
x t+1 = a x t (1− x t )
(14.1)
Yet such nonlinear systems are surely the rule, not the exception, outside the
physical sciences.’
D. Lloyd
Continuous monitoring of dissolved gases (O 2 , CO 2 and H 2 S, [96] by a submerged
probe, using membrane inlet mass spectrometry proved revelatory, especially when
employed in conjunction with intracellular redox state readout (NADPH, and flavins,
[17]. Transcriptional analyses using microarrays have revealed a global dynamic
architecture [18, 70, 71, 73], and that with respect to gene expression, the dominant
period is not the cell budding cycle (90–120 min), but more commonly the ~40 min
sub-multiple of that cycle period. Furthermore, wavelet analysis revealed genomewide oscillations in expression mirroring the 40 min respiratory oscillations in the self
synchronized continuous culture [72]. Two temporal clusters (4,679 of 5,329) were
maximally expressed in the reductive phase of the ~40-min cycle, and the third cluster
(650) in the respiratory stage [74]. Thus maximal expression of the gene super-cluster
important in respiration is functionally expressed oppositely in the cycle from those
genes known to be involved in reductive functions. The transcriptional cycle gates
synchronous bursts of DNA replication in a constant fraction of the population at
40 min intervals. It was also suggested [74], that the separation of DNA replication
into the reductive part of the ~40 min cycle represents an evolutionary important
mechanism for the obviation of oxidative damage (e.g. by reactive species derived
from partial reductive reactions of O 2 .
More than 1600 oscillating metabolites [2, 126, 129, 146] reveal coordination
with metabolic functions, organelle elaboration and function, and the cell division
cycle. Redox control is central in the cellular network and implicit to its rhythmicity
[129], and also to transcriptional processes and chromosome dynamics [2, 111, 112].
The detailed chronology of these coordinated research topics by collaborating
groups has been reviewed [1, 86, 104].
14.1.11 Non-linear Dynamics of the Self-synchronous
Culture: Chaos and Fractals
May [119] has written: ‘First-order difference equations arise in many contexts in
the biological, economic and social sciences. Such equations, even though simple
and deterministic, can exhibit a surprising array of dynamical behaviour, from stable
points, to a bifurcating hierarchy of stable cycles, to apparently random fluctuations.
There are consequently many fascinating problems, some concerned with delicate
mathematical aspects of the fine structure of the trajectories, and some concerned
with the practical implications and applications of the bizarre behaviour exhibited
by the simplest of discrete time, nonlinear systems, such as Eq. (14.1).
x t+1 = a x t (1− x t )
(14.1)
Yet such nonlinear systems are surely the rule, not the exception, outside the
physical sciences.’