Within-host competition selects for plasmid-encoded toxin–antitoxin systems

Host age modulates within-host parasite competition.

In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at expo...

The Role of Within-Host Competition for Coexistence in Multiparasitoid-Host Systems.

Multiparasitism (females of multiple species parasitizing the same host) is a ubiquitous phenomenon in parasitoids, yet the role of within-host competition has been mostly ignored in multiparasitoid-host models. Here we study the effect of varying the degree of competition at different life stages: competition over oviposition sites (between-adult competition) and larval competition over resour...

Replication of the broad host range plasmid RSF1010: requirement for three plasmid-encoded proteins.

Cloning of specific regions of plasmid RSF1010, in conjunction with in vitro replication studies, has revealed three novel genes: repA, repB, and repC. They are clustered in one region of the plasmid, separated from the origin of replication by regions that are not essential for plasmid viability in an Escherichia coli host. In vivo, a 2.1-kilobase segment of the plasmid, bearing the replicatio...

The Stability System of the Yeast 2 Micron Plasmid: Analysis of Plasmid and Host Encoded Components

Competition between plasmid-bearing and plasmid-free organisms in the host: population dynamics and antibiotic resistance.

OBJECTIVE To clarify the effects of antibiotic exposure on bacterial antibiotic resistance. MATERIALS AND METHODS A competitive population dynamics model for plasmid-bearing organisms and plasmid-free organisms in the host was established. The Poincaré-Bendixson theorem was used for analysis. RESULTS All possible results of the competition dependent on biologically meaningful parameters wer...