Evaluation of cell binding activities of Leptospira ECM adhesins.

Pathogenic spirochetes of the genus Leptospira are the causative agents of leptospirosis, a zoonotic infection that occurs globally. The bacteria colonize the renal proximal tubules of many animals and are shed in the urine. Contact with the urine, or with water contaminated with the urine of infected animals can cause infection of new host animals, including humans. Mechanisms of colonization of the proximal tubule and other tissues are not known, but specific interactions between bacterial adhesins and host substrates are likely to be critical in this process. Several extracellular matrix (ECM) adhesins have been previously identified, but more recently, it has been shown that Leptospira bind more efficiently to cells than ECM. In this work, recombinant forms of five putative Leptospira ECM adhesins, namely LipL32, Loa22, OmpL1, p31/LipL45, and LenA were evaluated for binding to cells as well as an expanded variety of ECM components. Reproducible and significant adhesin activity was demonstrated only for OmpL1, which bound to both mammalian cell lines tested and to glycosaminoglycans (GAGs). While determination of biologically significant bacterial adhesion activity will require generation of site-directed mutant strains, our results suggest that OmpL1 is a strong candidate for future evaluation regarding the roles of the adhesin activity of the protein during L. interrogans infection.

Bleach gel: a simple agarose gel for analyzing RNA quality.

RNA-based applications requiring high-quality, non-degraded RNA are a foundational element of many research studies. As such, it is paramount that the integrity of experimental RNA is validated prior to cDNA synthesis or other downstream applications. In the absence of expensive equipment such as microfluidic electrophoretic devices, and as an alternative to the costly and time-consuming standard formaldehyde gel, RNA quality can be quickly analyzed by adding small amounts of commercial bleach to TAE buffer-based agarose gels prior to electrophoresis. In the presence of low concentrations of bleach, the secondary structure of RNA is denatured and potential contaminating RNases are destroyed. Because of this, the 'bleach gel' is a functional approach that addresses the need for an inexpensive and safe way to evaluate RNA integrity and will improve the ability of researchers to rapidly analyze RNA quality.