Crp Induces Switching of the CsrB and CsrC RNAs in Yersinia pseudotuberculosis and Links Nutritional Status to Virulence.

Colonization of the intestinal tract and dissemination into deeper tissues by the enteric pathogen Yersinia pseudotuberculosis demands expression of a special set of virulence factors important for the initiation and the persistence of the infection. In this study we demonstrate that many virulence-associated functions are coregulated with the carbohydrate metabolism. This link is mediated by the carbon storage regulator (Csr) system, including the regulatory RNAs CsrB and CsrC, and the cAMP receptor protein (Crp), which both control virulence gene expression in response to the nutrient composition of the medium. Here, we show that Crp regulates the synthesis of both Csr RNAs in an opposite manner. A loss of the crp gene resulted in a strong upregulation of CsrB synthesis, whereas CsrC levels were strongly reduced leading to downregulation of the virulence regulator RovA. Switching of the Csr RNA involves Crp-mediated repression of the response regulator UvrY which activates csrB transcription. To elucidate the regulatory links between virulence and carbon metabolism, we performed comparative metabolome, transcriptome, and phenotypic microarray analyses and found that Crp promotes oxidative catabolism of many different carbon sources, whereas fermentative patterns of metabolism are favored when crp is deleted. Mouse infection experiments further demonstrated that Crp is pivotal for a successful Y. pseudotuberculosis infection. In summary, placement of the Csr system and important virulence factors under control of Crp enables this pathogen to link its nutritional status to virulence in order to optimize biological fitness and infection efficiency through the infectious life cycle

Investigation of drug product and container-closure interactions: A case study of diluent containing prefilled syringe.

Prefilled syringes (PFS) constitute a widely used medical device for drug delivery particularly for the drugs of biological origin. Interactions between the product contents and the components of the PFS play a critical role in determining the suitability of selected PFS. A diluent (with benzyl alcohol/BzOH as a preservative) containing PFS used for reconstitution of the lyophilized product revealed a systematic decrease in the BzOH content during accelerated and stress stability program. Investigation was carried out to understand and identify the underlying causes of this phenomenon. BzOH has a varying propensity to bind to the rubber components (stopper and tip-cap) of the PFS. Vapor permeation behavior across the tip-cap of the PFS was studied via headspace-gas chromatography-mass spectroscopy (HS-GC-MS) enabled analysis. Depending on the properties of the rubber components, BzOH can not only bind but also traverse across them, resulting in a systematic loss during the course of the stability. PFS can allow not only water vapor permeation across the tip-cap as shown in previous studies, but also molecules like benzyl alcohol. This phenomenon stresses the need for careful selection of the components of the primary packaging and also provides an opportunity to deploy novel tools like HS-GC-MS in the early selection of the optimal primary packaging configuration