The metabolic sensor PASK is a histone 3 kinase that also regulates H3K4 methylation by associating with H3K4 MLL2 methyltransferase complex.

The metabolic sensor Per-Arnt-Sim (Pas) domain-containing serine/threonine kinase (PASK) is expressed predominantly in the cytoplasm of different cell types, although a small percentage is also expressed in the nucleus. Herein, we show that the nuclear PASK associates with the mammalian H3K4 MLL2 methyltransferase complex and enhances H3K4 di- and tri-methylation. We also show that PASK is a histone kinase that phosphorylates H3 at T3, T6, S10 and T11. Taken together, these results suggest that PASK regulates two different H3 tail modifications involving H3K4 methylation and H3 phosphorylation. Using muscle satellite cell differentiation and functional analysis after loss or gain of Pask expression using the CRISPR/Cas9 system, we provide evidence that some of the regulatory functions of PASK during development and differentiation may occur through the regulation of these histone modifications.

Label-free capacitance-based identification of viruses.

This study was undertaken to quantitate a single virus suspension in culture medium without any pre-processing. The electrical capacitance per virus particle was used to identify the kind of virus present by measuring the suspension (virus plus medium) capacitance, de-embedding the medium contribution, and dividing by the virus count. The proposed technique is based on finding the single virus effective dielectric constant which is directly related to the virus composition. This value was used to identify the virus type accordingly. Two types of viruses thus tested were further quantified by a biochemical technique to validate the results. Furthermore, non-organic nanoparticles with known concentration and capacitance per particle were identified using the proposed method. The selectivity of the method was demonstrated by performing electrical measurements on a third virus, revealing that the proposed technique is specific and sensitive enough to permit detection of a few hundred virus particles per milliliter within a few minutes.

Interaction of curcumin with ß-lactoglobulin-stability, spectroscopic analysis, and molecular modeling of the complex.

Curcumin (diferuloyl methane) is the physiologically and pharmacologically active component of turmeric (Curcuma longa L.). Solubility and stability of curcumin are the limiting factors for realizing its therapeutic potential. ß-Lactoglobulin (ßLG), the major whey protein, can solubilize and bind many small hydrophobic molecules. The stability of curcumin bound to ßLG in solution is enhanced 6.7 times, in comparison to curcumin alone (in aqueous solution). The complex formation of curcumin with ßLG has been investigated employing spectroscopic techniques. ßLG interacts with curcumin at pH 7.0 with an association constant of 1.04 ± 0.1 × 10(5) M(-1) to form a 1:1 complex at 25 °C. Entropy and free energy changes for the interaction derived from the van't Hoff plot are 18.7 cal mol(-1) K(-1) and -6.8 kcal mol(-1) at 25 °C, respectively; the interaction is hydrophobic in nature. The interaction of ßLG with curcumin does not affect either the conformation or the state of association of ßLG. Competitive ligand binding measurements, binding studies with denatured ßLG, effect of pH on the curcumin-ßLG interaction, Förster energy transfer measurements, and molecular docking studies suggest that curcumin binds to the central calyx of ßLG. These binding studies have prompted the preparation and encapsulation of curcumin in ßLG nanoparticles. Nanoparticles of ßLG prepared by desolvation are found to encapsulate curcumin with >96% efficiency. The solubility of curcumin in ßLG nanoparticle is significantly enhanced to ∼625 µM in comparison with its aqueous solubility (30 nM). Nanoparticles of ßLG, by virtue of their ability to enhance solubility and stability of curcumin, may fit the choice as a carrier molecule.