We validate a model for the population dynamics, as they occur in a chemostat environment, of the green algae Raphidocelis subcapitata, a species that is often used as a primary food source in toxicity experiments for the fresh water crustacean Daphnia magna. We collected longitudinal data from 4 replicate population experiments with R. subcapitata. This data was fit to a logistical growth mode...

The size stability of natural populations indicates that natality and mortality rates are on average equal. Fine tuning of the two independent processes suggests the existence of a regulating mechanism. Two types of such mechanisms exist. A decrease in the number of organisms can either speed up the natality rate or slow down the mortality rate. The former mechanism (chemostat-like) acts whenev...

Protein expression is shaped by evolutionary pressures. Due to limitations in biosynthetic capacity, the costs and benefits of enzyme production are important determinants of fitness. While these processes are well understood in batch conditions, in chemostats, which are extensively used to study microbial evolution in a laboratory setting, a feedback of the microbial physiology on the conditio...

We investigate the standard chemostat model when lateral gene transfer is taken into account. We will show that when the different genotypes have growth rate functions that are sufficiently close to a common growth rate function, and when the yields of the genotypes are sufficiently close to a common value, then the population evolves to a globally stable steady state, at which all genotypes co...

Analysis of the Luedeking-Piret model during the oxidative respiration to respirofermentative transition in a consortium grown in a chemostat revealed a significant increase in a parameter (β) of the Luedeking-Piret model in butyrate production. These data implied the possibility of improved capacity for cellular metabolites production under some culture conditions. Additionally, the parameter ...

Segregational instability models of recombinant bacteria conventionally assume that (a) the probability of loss of a unit of a plasmid is constant and (b) upon cell division, the progeny either inherit the mother’s plasmid content entirely or not at all. However, two previous studies have shown that neither assumption is correct. So, in this work, both assumptions have been relaxed to formulat...

A model of competit ion between plasmid-bearing and plasmid-free organisms in a chemostat was proposed in a paper of Stephanopoulis and Lapidus. The model was in the form of a system of nonlinear ordinary differential equations. Such models are relevant to commercial production by genetically altered organisms in continuous culture. The analysis there was local (using index arguments). This pap...