In Vitro and Sensory Evaluation of Capsaicin-Loaded Nanoformulations

Capsaicin has known health beneficial and therapeutic properties. It is also able to enhance the permeability of drugs across epithelial tissues. Unfortunately, due to its pungency the oral administration of capsaicin is limited. To this end, we assessed the effect of nanoencapsulation of capsaicin, under the hypothesis that this would reduce its pungency. Core-shell nanocapsules with an oily core and stabilized with phospholipids were used. This system was used with or without chitosan coating. In this work, we investigated the in vitro release behavior of capsaicin-loaded formulations in different physiological media (including simulated saliva fluid). We also evaluated the influence of encapsulation of capsaicin on the cell viability of buccal cells (TR146). To study the changes in pungency after encapsulation we carried out a sensory analysis with a trained panel of 24 students. The in vitro release study showed that the systems discharged capsaicin slowly in a monotonic manner and that the chitosan coating had an effect on the release profile. The cytotoxic response of TR146 cells to capsaicin at a concentration of 500 μM, which was evident for the free compound, was reduced following its encapsulation. The sensory study revealed that a chitosan coating results in a lower threshold of perception of the formulation. The nanoencapsulation of capsaicin resulted in attenuation of the sensation of pungency significantly. However, the presence of a chitosan shell around the nanoformulations did not mask the pungency, when compared with uncoated systems.     

Cell Elasticity Is Regulated by the Tropomyosin Isoform Composition of the Actin Cytoskeleton

The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments.     

Purification and partial characterization of a bovine epidermal growth factor-like polypeptide

A heterologous radioreceptor assay was developed to follow the purification of an EGF-like polypeptide from bovine kidney. Purification of the growth factor was facilitated by the use of a novel affinity column using fixed A431 cells attached to sephadex beads. The mol. wt. of the purified EGF-LP was estimated to be 5480 from the amino acid composition. The purified EGF-like polypeptide stimulated the proliferation of bovine mammary epithelial cells and appeared to be equipotent to mouse EGF. Available evidence suggests that the purified molecule is distinct from bovine TGF-alpha.     

Experimental and Theoretical Assessment of Ni‐Based Binary Compounds for the Hydrogen Evolution Reaction

Metallic binary compounds have emerged in recent years as highly active and stable electrocatalysts toward the hydrogen evolution reaction. In this work, the origin of their high activity from a theoretical and experimental point of view is elucidated. Here, different metallic ceramics as Ni₃S₂, Ni₃N, or Ni₅P₄ are grown directly on Ni support in order to avoid any contaminations. The correlation of theoretical calculations with detailed material characterization and electrochemical testing paves the way to a deeper understanding of possible active adsorption sites for each material and the observed catalytic activity. It is shown that heteroatoms as P, S, and N actively take part in the reaction and do not act as simple spectator. Due to the anisotropic nature of the materials, a variety of adsorption sites with highly coverage‐dependent properties exists, leading to a general shift in hydrogen adsorption free energies ΔG _H close to zero. Extending the knowledge gained about the here described materials, a new catalyst is prepared by modifying a high surface Ni foam, for which current densities up to 100 mA cm^?2 at around 0.15 V (for Ni₃N) are obtained.     

Mutual interplay between phytopathogenic powdery mildew fungi and other microorganisms

Powdery mildew is a common and widespread plant disease of considerable agronomic relevance. It is caused by obligate biotrophic fungal pathogens which, in most cases, epiphytically colonize aboveground plant tissues. The disease has been typically studied as a binary interaction of the fungal pathogen with its plant hosts, neglecting, for the most part, the mutual interplay with the wealth of other microorganisms residing in the phyllo- and/or rhizosphere and roots. However, the establishment of powdery mildew disease can be impacted by the presence/absence of host-associated microbiota (epi- and endophytes) and, conversely, plant colonization by powdery mildew fungi might disturb indigenous microbial community structures. In addition, other (foliar) phytopathogens could interact with powdery mildews, and mycoparasites may affect the outcome of plant–powdery mildew interactions. In this review, we discuss the current knowledge regarding the intricate and multifaceted interplay of powdery mildew fungi, host plants and other microorganisms, and outline current gaps in our knowledge, thereby setting the basis for potential future research directions.     

Profiling SARS-CoV-2 HLA-I peptidome reveals T cell epitopes from out-of-frame ORFs

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Isolation of a heat-stable maize endosperm ADP-glucose pyrophosphorylase variant

Heat stress reduces maize yield and several lines of evidence suggest that the heat lability of maize endosperm ADP-glucose pyrophosphorylase (AGPase) contributes to this yield loss. AGPase catalyzes a rate-limiting step in starch synthesis. Herein, we present a novel maize endosperm AGPase small subunit variant, termed BT2-TI that harbors a single amino acid change of residue 462 from threonine to isoleucine. The mutant was isolated by random mutagenesis and heterologous expression in a bacterial system. BT2-TI exhibits enhanced heat stability compared to wildtype maize endosperm AGPase.The TI mutation was placed into another heat-stable small subunit variant, MP. MP is composed of sequences from the maize endosperm and the potato tuber small subunit. The MP-TI small subunit variant exhibited greater heat stability than did MP. Characterization of heat stability as well as kinetic and allosteric properties suggests that MP-TI may lead to increased starch yield when expressed in monocot endosperms.     

DEVELOPMENTAL FEATURES OF THE SPERMATOGENOUS CELL IN GINKGO BILOBA

A “double-blepharoplast” originates de novo in the spermatogenous cell of Ginkgo biloba L. Initially, the double-blepharoplast consists of two opposing hemispherical bodies comprised of densely staining material. The two blepharoplasts seemingly are pushed apart by the formation of densely packed fibrils which are oriented perpendicular to the distal, rounded edges of the two future blepharoplasts. As the latter move apart, each one develops lightly staining channels which are often organized in a hub and spoke configuration (procentrioles). Microtubules extend from the blepharoplasts as the latter move to their final position in the cell, and centrioles (probasal bodies) become organized at the periphery of each blepharoplast. Two large “osmiophilic globules,” conspicuous entities close to the nucleus of the mature spermatogenous cell, arise de novo. A fibrillogranular body in the cytoplasm, always closely associated with the nucleus, also arises de novo.