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A series of synthetic riboswitches were developed to function as genetic control elements in a diverse species of Gram-negative and Gram-positive bacteria. The developed riboswitches could be applied for controlling gene expression in a multitude of bacterial species that lack ligand-inducible expression systems.

The study describes a new methodology by which any bacteria with small molecules and RNA can be easily guided toward and precisely localized to a completely new chemical signal and environment. The results show that in spite of being a very difficult task due to the complexities of the bacteria, the shift can be extremely useful for creating several new powerful opportunities in bioremediation and synthetic biology.

A genetic toolbox of natural and engineered protein modules is used to create several materials that form reversible networks in the presence of [Ca.sup.2+]. The modular framework can be extended to create a variety of new sensing materials using modules from the diverse array of signaling pathways that are mediated by reversible protein-protein interactions.

The article focuses on the research of a genetic toolbox system comprising natural and engineered protein modules to create several materials that form reversible networks in the presence of calcium. Researchers rationally controlled the architectures, sensing behavior, and rheological properties of the material by choosing appropriate modules. These modules are on the basis of their dilute solution behavior.

A correction to the article "Synthetic Riboswitches That Induce Gene Expression in Diverse Bacterial Species" that was published in the 2010 issue is presented.

Synthetic riboswitches constructed from RNA aptamers provide a means to control bacterial gene expression using exogenous ligands. A common theme among riboswitches that function at the translational level is that the RNA aptamer interacts with the ribosome-binding site (RBS) of a gene via an intervening sequence known as an expression platform. Structural rearrangements of the expression platform convert ligand binding into a change in gene expression. While methods for selecting RNA aptamers that bind ligands are well established, few general methods have been reported for converting these aptamers into synthetic riboswitches with desirable properties. We have developed two such methods that not only provide the throughput of genetic selections, but also feature the quantitative nature of genetic screens. One method, based on cell motility, is operationally simple and requires only standard consumables; while the other, based on fluorescence-activated cell sorting (FACS), is particularly adept at identifying synthetic riboswitches that are highly dynamic and display very low levels of background expression in the absence of the ligand. Here we present detailed procedures for screening libraries for riboswitches using the two methods.