Hemophagocytic Lymphohistiocytosis Associated with Salmonella typhi Infection in a Child: A Case Report with Review of Literature

We present the case of an 8-year-old girl with hemophagocytic lymphohistiocytosis secondary to a Salmonella typhi infection. She received antibiotic treatment and intravenous immunoglobulin with complete resolution of the symptoms. We present a review of previously reported pediatric cases and propose a gradual approach to treatment.

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Contact order is a determinant for the dependence of GFP folding on the chaperonin GroEL

The GroE chaperonin system facilitates protein folding in an ATP-dependent manner. It has remained unclear why some proteins are obligate clients of the GroE system whereas other closely related proteins are able to fold efficiently in its absence. Factors that cause folding to be slower affect kinetic partitioning between spontaneous folding and chaperone binding in favor of the latter. One such potential factor is contact order, which is the average separation in sequence between residues that are in contact in the native structure.

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MyDEP: a new computational tool for dielectric modeling of particles and cells

Dielectrophoresis (DEP) and electrorotation (ROT) are two electrokinetic phenomena exploiting non-uniform electric fields to exert a force or torque on biological particles suspended in liquid media. They are widely used in lab-on-chip devices for the manipulation, trapping, separation and characterization of cells, microorganisms and other particles. The DEP force and ROT torque depend on the respective polarizabilities of the particle and medium, which in turn depend on their dielectric properties and on the field frequency.

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Constraints on GPCR heterodimerization revealed by the type-4 induced-association BRET assay

G protein-coupled receptors (GPCRs) comprise the largest and most pharmacologically important family of cell-surface receptors encoded by the human genome. In many instances the distinct signaling behavior of certain GPCRs has been explained in terms of the formation of heteromers with, for example, distinct signaling properties and allosteric cross-regulation. Confirmation of this has, however, been limited by the paucity of reliable methods for probing heteromeric GPCR interactions in situ. The most widely used assays for GPCR stoichiometry, based on resonance energy transfer (RET), are unsuited to reporting heteromeric interactions.

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Conformations of an RNA Helix-Junction-Helix Construct revealed by SAXS Refinement of MD Simulations

Ribonucleic acid (RNA) is involved in a broad range of biological processes that extend far beyond translation. Many of RNAs recently discovered functions rely on folding to a specific conformation or transitioning between conformations. RNA structure contains rigid, short base-paired regions connected by more flexible linkers. Studies of model constructs such as small helix-junction-helix (HJH) motifs are useful in understanding how these elements work together to determine RNA conformation. Here, we reveal the full ensemble of solution structures assumed by a model RNA HJH.

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Convection-induced biased distribution of actin probes in live cells

Fluorescent markers that bind endogenous target proteins are frequently employed for quantitative live-cell imaging. To visualize the actin cytoskeleton in live cells, several actin-binding probes have been widely used. Among them, Lifeact is the most popular probe with ideal properties including fast exchangeable binding kinetics. Because of its fast kinetics, Lifeact is generally believed to distribute evenly throughout cellular actin structures. In this study, however, we demonstrate misdistribution of Lifeact toward the rear of lamellipodia where actin filaments continuously move inward along the retrograde flow.

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New and Notables

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