Construction of the lactate-sensing fibremats by confining sensor fluorescent protein of lactate inside nanofibers of the poly(HPMA/DAMA)/ADH-nylon 6 core-shell fibremat.

The development of a new materials platform capable of sustaining the functionality of proteinous sensor molecules over an extended period without being affected by biological contaminants in living systems, such as proteases, is highly demanded. In this study, our primary focus was on fabricating new core-shell fibremats using unique polymer materials, capable of functionalizing encapsulated sensor proteins while resisting the effects of proteases. The core-fibre parts of core-shell fibremats were made using a newly developed post-crosslinkable water-soluble copolymer, poly(2-hydroxypropyl methacrylamide)-co-poly(diacetone methacrylamide), and the bifunctional crosslinking agent, adipic dihydrazide, while the shell layer of the nanofibers was made of nylon 6. Upon encapsulating the lactate-sensor protein eLACCO1.1 at the core-fibre part, the fibremat exhibited a distinct concentration-dependent fluorescence response, with a dynamic range of fluorescence alteration exceeding 1000% over the lactate concentration range of 0 to 100 mM. The estimated dissociation constant from the titration data was comparable to that estimated in a buffer solution. The response remained stable even after 5 cycles and in the presence of proteases. These results indicates that our core-shell fibremat platform could serve as effective immobilizing substrates for various sensor proteins, facilitating continuous and quantitative monitoring of various low-molecular-weight metabolites and catabolites in a variety of biological samples.

Computational fluid dynamics-based modeling and optimization of flow rate and radiant exitance for 1,4-dioxane degradation in a vacuum ultraviolet photoreactor.

1,4-Dioxane is one of the most persistent organic micropollutants in conventional drinking-water-treatment processes. Vacuum ultraviolet (VUV) treatment is a promising means of removing micropollutants such as 1,4-dioxane from source water, but this approach has not yet been implemented in a full-scale water treatment plant, partly because the operating parameters for pilot and full-scale VUV photoreactors have not been optimized. Here, we developed a computational fluid dynamics-based method for optimizing VUV photoreactor performance through energy-based analyses that take into account the effects of two important operating parameters-flow rate and radiant exitance. First, we constructed a computational fluid dynamics model and determined the sole parameter required for the model, the pseudo-first-order rate constant for the reaction of 1,4-dioxane, by simple batch experiment. Then, we validated the model by using a pilot-scale flow-through annular photoreactor. Finally, we used the validated model to examine the effects of flow rate and radiant exitance on the efficiency of 1,4-dioxane degradation in a virtual annular photoreactor. Radiation efficiency, which was defined as the ratio of the logarithmic residual ratio of 1,4-dioxane to the theoretical minimum logarithmic residual ratio (best possible performance) under the given operating conditions, was calculated as an energy-based index of cost-effectiveness. Radiation efficiency was found to increase with increasing flow rate but decreasing radiant exitance. An electrical energy per order (EEO) analysis suggested that VUV treatment under laminar flow was most economical when low-power lamps and a high flow rate were used. In contrast, VUV treatment under turbulent flow was suggested to be most economical when high-power lamps were used at a high flow rate.

CAPS1 is involved in hippocampal synaptic plasticity and hippocampus-associated learning.

Calcium-dependent activator protein for secretion 1 (CAPS1) is a key molecule in vesicular exocytosis, probably in the priming step. However, CAPS1's role in synaptic plasticity and brain function is elusive. Herein, we showed that synaptic plasticity and learning behavior were impaired in forebrain and/or hippocampus-specific Caps1 conditional knockout (cKO) mice by means of molecular, physiological, and behavioral analyses. Neonatal Caps1 cKO mice showed a decrease in the number of docked vesicles in the hippocampal CA3 region, with no detectable changes in the distribution of other major exocytosis-related molecules. Additionally, long-term potentiation (LTP) was partially and severely impaired in the CA1 and CA3 regions, respectively. CA1 LTP was reinforced by repeated high-frequency stimuli, whereas CA3 LTP was completely abolished. Accordingly, hippocampus-associated learning was severely impaired in adeno-associated virus (AAV) infection-mediated postnatal Caps1 cKO mice. Collectively, our findings suggest that CAPS1 is a key protein involved in the cellular mechanisms underlying hippocampal synaptic release and plasticity, which is crucial for hippocampus-associated learning.

Stereoselective synthesis of Gly-Gly-type (E)-methylalkene and (Z)-chloroalkene dipeptide isosteres and their application to 14-mer RGG peptidomimetics.

Stereoselective and efficient synthesis of Gly-Gly-type (E)-methylalkene and (Z)-chloroalkene dipeptide isosteres is realized by organocuprate-mediated single electron transfer reduction. The synthetic isosteres can be used in Fmoc-based solid phase peptide synthesis, resulting in the preparation of the 14-mer RGG peptidomimetics containing an (E)-methylalkene or a (Z)-chloroalkene unit.

A novel analytical procedure for assaying lysozyme activity using an end-blocked chitotetraose derivative as substrate.

An end-modified ß-d-galactosyl chitotetraose derivative [44-O-ß-d-galactosyl-ß-tri-N-acetylchitotriosyl 2-acetamide-2,3-dideoxy-glucopyranose; Gal(GlcN)3D] was designed and synthesized from chitin tetrasaccharide. The derivative was chemically modified by dehydration of the reducing end GlcN and enzymatic addition of a Gal group to the non-reducing end GlcN. Hydrolysis of Gal(GlcN)3D and related compounds using hen egg-white lysozyme was then examined. Gal(GlcN)3D was specifically cleaved to Gal(GlcN)2 and GlcND. Kinetic studies and docking simulations were further conducted to elucidate its mode of binding to lysozyme. These analyses revealed the binding of Gal(GlcN)3D to lysozyme is more favorable than that of (GlcN)4D. We conclude the 4-O-substituted Gal group at the non-reducing end of Gal(GlcN)3D does not prohibit the action of lysozyme, but gives some affinity to the subsite (i.e. equivalent to GlcN). From these results, a new assay method for quantifying lysozyme was established by utilizing the Morgan-Elson reaction based on the generation of product D (2-acetamide-2,3-dideoxy-glucopyranose), which serves as a chromophore, formed from Gal(GlcN)3D by lysozyme through a conjugated reaction involving ß-N-acetylhexosaminidase. The assay system gave a linear dose-response curve in the range of 2-31 µg of lysozyme during a 15 min incubation. This novel assay method for the quantification of lysozyme is highly specific, sensitive, accurate and reproducible.