Abstract:
:In continuous phosphate-limited conditions, under pH control from high pH (pH ≳ 5.2) to low pH (pH ≲ 5.2), the metabolism of the Gram-positive bacterium Clostridium acetobutylicum,switches from acid to solvent production. Three main enzymes are responsible for the shift, acetoacetate decarboxylase (Adc), alcohol dehydrogenase (AdhE1/2) and a CoA-transferase (CtfA/B), which are produced in increased quantities during solventogenesis. A two-population model, Millat et al. (2013) and fitted to such 'forward'-shift data, can explain this, as well as observed changes in optical density immediately following the shift: an acidogenic subpopulation is washed out and a solventogenic subpopulation grows in its place, each with distinct physiologies and proteomes. We fit this model to a 'reverse'-shift experiment, where the pH is increased from solventogenic to acidogenic conditions. We find corresponding changes in reaction rates, with AdhE1 and Adc production falling, as in the 'forward' experiments; however, for CtfA/B, the best fit surprisingly arises from the same level of production in both conditions. We propose experiments that would test whether this is a model artefact or accurately reflects cultures shifted in this reverse direction, and, if true, may suggest that over-expressing CtfA/B in both solventogenic and acidogenic conditions could improve the efficiency of fermentation.
journal_name
Math Bioscijournal_title
Mathematical biosciencesauthors
Thorn GJ,King JRdoi
10.1016/j.mbs.2016.03.003subject
Has Abstractpub_date
2016-06-01 00:00:00pages
101-13eissn
0025-5564issn
1879-3134pii
S0025-5564(16)00059-6journal_volume
276pub_type
杂志文章abstract::This paper considers the geometry of plants with golden spiral phyllotaxis, i.e. growing leaf by leaf on a spiral with golden divergence angle, via the simplest mathematical model, a cylinder with regular arrangement of points on its surface. As is well-known, Fibonacci numbers appear by means of the order of parastic...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2018.05.003
更新日期:2018-07-01 00:00:00
abstract::The existence of cooperation in this world is a mysterious phenomenon. One of the mechanisms that explain the evolution of cooperation is repeated interaction. If interactions between the same individuals repeat and individuals cooperate conditionally, cooperation can evolve. A previous study pointed out that if indiv...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2017.04.002
更新日期:2017-07-01 00:00:00
abstract::Most endocrine cells secrete hormones as a result of Ca2+-regulated exocytosis, i.e., fusion of the membranes of hormone-containing secretory granules with the cell membrane, which allows the hormone molecules to escape to the extracellular space. As in neurons, electrical activity and cell depolarization open voltage...
journal_title:Mathematical biosciences
pub_type: 杂志文章,评审
doi:10.1016/j.mbs.2016.11.010
更新日期:2017-01-01 00:00:00
abstract::A class of models is considered in which the number of unknown parameters exceeds the number of independent equations that are derived from the input/observation configuration. It is shown that, under certain circumstances, if the number of unknown parameters is sufficiently decreased by setting some of the exit param...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/0025-5564(95)00049-6
更新日期:1996-03-01 00:00:00
abstract::An epidemic model with multiple stages of infection is studied. The model allows for infected individuals to move from advanced stages of infection back to less advanced stages of infection. A threshold parameter which determines the local stability of the disease free equilibrium is found and interpreted. Under condi...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(02)00149-9
更新日期:2003-01-01 00:00:00
abstract::A three-dimensional diffusion model with either hexagonal or cylindrical symmetry has been constructed to simulate desorption profiles of hydrophilic chemicals from the topmost layer of human skin (the stratum corneum) as measured in ex vivo studies. The tissue is pierced by skin appendages - sweat glands and hair fol...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2018.03.010
更新日期:2018-06-01 00:00:00
abstract::The problem of biological invasion in a model single-species community is considered, the spatiotemporal dynamics of the system being described by a modified Fisher equation. For a special case, we obtain an exact solution describing self-similar growth of the initially inhabited domain. By comparison with numerical s...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(01)00068-2
更新日期:2001-08-01 00:00:00
abstract::Rooted phylogenetic networks provide an explicit representation of the evolutionary history of a set X of sampled species. In contrast to phylogenetic trees which show only speciation events, networks can also accommodate reticulate processes (for example, hybrid evolution, endosymbiosis, and lateral gene transfer). A...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2019.04.009
更新日期:2019-07-01 00:00:00
abstract::Cell cycle duration and phase transition times are not fixed, even within homogeneous cell populations growing under optimal environmental conditions. We investigate G(1) phase variability from the molecular point of view and propose a mathematical approach to model the protein interactions regulating the transition f...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(02)00085-8
更新日期:2002-05-01 00:00:00
abstract::Cooperating behaviors abound across all domains of life, but are vulnerable to invasion by cheaters. An important evolutionary question is to determine mechanisms that stabilize and maintain cooperation levels and prevent population collapse. Policing is one strategy populations may employ to achieve this goal, and it...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2019.108257
更新日期:2019-10-01 00:00:00
abstract::We consider the spread of an epidemic through a population divided into n sub-populations, in which individuals move between populations according to a Markov transition matrix Σ and infectives can only make infectious contacts with members of their current population. Expressions for the basic reproduction number, R₀...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2012.01.002
更新日期:2012-03-01 00:00:00
abstract::We discuss an N-dimensional model for diffusion of age dependent populations. Let rho(x, t, a) be the population density at time t, age a and spatial position x, and let u(x, t) = [formula: see text] rho(x, t, a) da be the total population at t and x. The directed dispersal model to be discussed, with diffusion depend...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(97)10014-1
更新日期:1998-04-01 00:00:00
abstract::Employing theoretical models, we show that the sterile insect release method (SIRM) can give rise to traveling waves of fertile insects. The velocity of these waves depends critically upon the density of sterile insects (and thus upon the rate at which sterile individuals are being released into the environment). When...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/0025-5564(93)90067-k
更新日期:1993-08-01 00:00:00
abstract::Many microbial ecosystems can be seen as microbial 'food chains' where the different reaction steps can be seen as such: the waste products of the organisms at a given reaction step are consumed by organisms at the next reaction step. In the present paper we study a model of a two-step biological reaction with feedbac...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2016.02.008
更新日期:2016-05-01 00:00:00
abstract::This paper describes an efficient method for tracing interactions between a radiation track and molecular targets in a cell or nucleus. The method is efficient because it ensures that a minimal subset of interactions in the track needs to be tested for each score. It is most useful for high-energy particles since the ...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(98)10045-7
更新日期:1998-12-15 00:00:00
abstract::An inherent problem in studying the behavior of a metabolic pathway is the impossibility of developing a complete, detailed model that includes all the cellular processes that have an impact on the set of fluxes in such a pathway. Lacking this, one requires some means of modeling the interactions between a metabolic p...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/0025-5564(90)90049-5
更新日期:1990-06-01 00:00:00
abstract::An optimal input of nutrients into the metabolic process of the individual subject so as to effect desired therapeutic results is particularly important for the critically ill. A patient-related, individualized nutrients optimization procedure is proposed here. The procedure is applicable to any time-invariant and det...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/0025-5564(89)90004-7
更新日期:1989-12-01 00:00:00
abstract::Traits such as skill at foraging and investment in anti-predator defense may vary among individuals within a species population. This intraspecific variation has implications for community dynamics. The implications of intraspecific variation of a consumer in the intermediate level of a tritrophic food chain are explo...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2013.04.008
更新日期:2013-08-01 00:00:00
abstract::The contraction of intestinal smooth muscle cells (ISMCs) involves many coordinated biochemical and mechanical processes. In this work, we present a framework for modeling ISMC contractility that begins with chemical models of calcium dynamics, continues with myosin light chain phosphorylation and force generation, an...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2014.12.009
更新日期:2015-04-01 00:00:00
abstract::The resurgence of tuberculosis in the 1990s and the emergence of drug-resistant tuberculosis in the first decade of the 21st century increased the importance of epidemiological models for the disease. Due to slow progression of tuberculosis, the transmission dynamics and its long-term effects can often be better obser...
journal_title:Mathematical biosciences
pub_type: 杂志文章,评审
doi:10.1016/j.mbs.2012.02.003
更新日期:2012-04-01 00:00:00
abstract::We explore the feasibility of deriving generalised expressions for the probability mass function (PMF) of the final epidemic size of a Susceptible - Infected - Recovered (SIR) model on a finite network of an arbitrary number of nodes. Expressions for the probability that the infection progresses along a given pathway ...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2019.02.003
更新日期:2019-05-01 00:00:00
abstract::Interaction of metal or oxide nanoparticles (NPs) with biological soft matter is one of the central phenomena in basic and applied biology-oriented nanoscience. Often, this interaction includes adsorption of suspended proteins on the NP surface, resulting in the formation of the protein corona around NPs. Structurally...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2016.09.018
更新日期:2016-12-01 00:00:00
abstract::During normal, voluntary movements, skeletal muscles typically contract in a highly dynamic manner; the length of the muscle and the speed of contraction change continuously. In this study, we present an approach to predict the accurate behavior of muscles for such dynamic contractions using Huxley's cross-bridge mode...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(96)00115-0
更新日期:1997-01-01 00:00:00
abstract::This paper considers complex models arising in sociobiology. These combine genetic and strategic aspects to model the effect of gene-linked strategies on the ability of individuals to survive to maturity, mate and produce offspring. Several important models considered in the literature are generalised and extended to ...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/s0025-5564(98)10011-1
更新日期:1998-08-01 00:00:00
abstract::The problem addressed is that of finding the harvesting policy that will maximize the yield and maintain a given population in a steady state. It is assumed that the equations describing the evolution of the population and the yield are linear but that the equation describing reproduction is nonlinear (density depende...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/0025-5564(94)90039-6
更新日期:1994-03-01 00:00:00
abstract::We numerically investigate the influence of intrinsic channel noise on the dynamical response of delay-coupling in neuronal systems. The stochastic dynamics of the spiking is modeled within a stochastic modification of the standard Hodgkin-Huxley model wherein the delay-coupling accounts for the finite propagation tim...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2013.02.007
更新日期:2013-09-01 00:00:00
abstract::A two-state variable model in which saturable binding takes place is studied. Two mathematical representations of the same model are considered, one a standard chemical kinetics type of polynomial system, the other a reduced model formed from the original system via a pseudo-steady-state approximation. For a particula...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/0025-5564(95)00064-x
更新日期:1996-04-01 00:00:00
abstract::The influence of intrinsic channel noise on the spiking activity of excitable membrane patches is studied by use of a stochastic generalization of the Hodgkin-Huxley model. Internal noise stemming from the stochastic dynamics of individual ion channels does affect the electric properties of the cell-membrane patches. ...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2006.08.024
更新日期:2007-06-01 00:00:00
abstract::The coffee berry borer (CBB, Hypothenemus hampei) is the most serious insect pest of coffee worldwide; understanding the dynamics of its reproduction is essential for pest management. The female CBB penetrates the coffee berry, eats the seed, and reproduces inside it. A mathematical model of the infestation progress o...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2020.108530
更新日期:2021-01-21 00:00:00
abstract::Game theoretic tools are utilized to analyze a one-locus continuous selection model of sex-specific meiotic drive by considering nonequivalence of the viabilities of reciprocal heterozygotes that might be noticed at an imprinted locus. The model draws attention to the role of viability selections of different types to...
journal_title:Mathematical biosciences
pub_type: 杂志文章
doi:10.1016/j.mbs.2015.10.013
更新日期:2016-01-01 00:00:00