Utilizing a divalent metal ion transporter to control biogenic nanoparticle synthesis.

Unlabelled: Biogenic synthesis of inorganic nanomaterials has been demonstrated for both wild and engineered bacterial strains. In many systems the nucleation and growth of nanomaterials is poorly controlled and requires concentrations of heavy metals toxic to living cells. Here, we utilized the tools of synthetic biology to engineer a strain of Escherichia coli capable of synthesizing cadmium sulfide nanoparticles from low concentrations of reactants with control over the location of synthesis.

Membrane-Binding Biomolecules Influence the Rate of Vesicle Exchange between Bacteria.

The exchange of bacterial extracellular vesicles facilitates molecular exchange between cells, including the horizontal transfer of genetic material. Given the implications of such transfer events on cell physiology and adaptation, some bacterial cells have likely evolved mechanisms to regulate vesicle exchange. Past work has identified mechanisms that influence the formation of extracellular vesicles, including the production of small molecules that modulate membrane structure; however, whether these mechanisms also modulate vesicle uptake and have an overall impact on the rate of vesicle exchange is unknown.

Intertemporal trade-off between population growth rate and carrying capacity during public good production.

Public goods are biomolecules that benefit cellular populations, such as by providing access to previously unutilized resources. Public good production is energetically costly. To reduce this cost, populations control public good biosynthesis, for example using density-dependent regulation accomplished by quorum sensing.

Formation, collective motion, and merging of macroscopic bacterial aggregates.

Chemotactic bacteria form emergent spatial patterns of variable cell density within cultures that are initially spatially uniform. These patterns are the result of chemical gradients that are created from the directed movement and metabolic activity of billions of cells. A recent study on pattern formation in wild bacterial isolates has revealed unique collective behaviors of the bacteria Enterobacter cloacae.

Threshold effect of growth rate on population variability of cell lengths.

A long-standing question in biology is the effect of growth on cell size. Here, we estimate the effect of growth rate () on population cell size distributions by estimating the coefficient of variation of cell lengths (CV) from image analysis of fixed cells in DIC microscopy. We find that the CV is constant at growth rates less than one division per hour, whereas above this threshold, CV increases with an increase in the growth rate.

Automated Multi-Peak Tracking Kymography (AMTraK): A Tool to Quantify Sub-Cellular Dynamics with Sub-Pixel Accuracy.

Kymographs or space-time plots are widely used in cell biology to reduce the dimensions of a time-series in microscopy for both qualitative and quantitative insight into spatio-temporal dynamics. While multiple tools for image kymography have been described before, quantification remains largely manual. Here, we describe a novel software tool for automated multi-peak tracking kymography (AMTraK), which uses peak information and distance minimization to track and automatically quantify kymographs, integrated in a GUI.