Reddish coloration of Chinese quince (Pseudocydonia sinensis) procyanidins during heat treatment and effect on antioxidant and antiinfluenza viral activities

To investigate the effects of processing Chinese quince fruit on the denaturation of phenolics and their food functions, fruit phenolic extracts were heated together with organic acid for up to 12 h. Chinese quince phenolic (mostly procyanidins) solution subjected to heat treatment changed from almost colorless, pale yellow, to a reddish color. Before heat treatment, the absorption spectra of polymeric procyanidins were observed only around 280 nm; after heat treatment, absorption occurred between 400 and 600 nm, which is related to the reddish color appearance. Thioacidolysis of denatured reddish phenolics showed that (-)-epicatechin subunits decreased during heat treatment and, in contrast, cyanidin increased. In addition, novel substances that could not be degraded by thioacidolysis were formed. Meanwhile, antioxidant activities, assessed by linoleic acid peroxidation, 1,1-diphenyl-2-picrylhydrazyl (DPPH), Folin-Ciocalteu, and FRAP methods, increased during heat treatment. The antiinfluenza viral activity of denatured reddish phenolics was inferior to that of intact fruit phenolics; however, they retained moderate activity. These results indicate that red coloration of fruit products of Chinese quince was mainly due to the spectral (i.e. structural) changes of procyanidins accompanied with formation of cyanidin. Increasing the length of heat treatment increased the antioxidant capacity of phenolics, and the resultant reddish phenolics retained moderate antiinfluenza viral activity.     

Indirect evaluation of hardness and delamination strength of Akoya cultured pearl nacre based on UV fluorescence intensity

The durability of Akoya pearls is closely related to the mechanical strength of the nacre. Therefore, obtaining information about the mechanical strength of the nacre is very important in the quality control of pearls. The nacre of Akoya pearls is composed of aragonite contained within an organic matrix. The presence of the organic matrix provides mechanical strength and fracture toughness much higher than that of monolithic aragonite. In this study, we investigated the hardness and delamination strength of Akoya cultured pearls classified into four levels by “Gray Value (GV)”, a score given by a non-destructive inspection method based on UV fluorescence intensity that provides an indication of the condition of the nacre’s organic components. Pearl hardness decreased significantly with decreasing GV. Furthermore, delamination strength of the pearl surface layer was very low when the GV was very low. These results suggest that the GV indirectly represents the mechanical strength of the nacre and could be used as a non-destructive quality-control method to maintain the quality of pearls used as jewelry.

     

Changes of lymphocyte subpopulations and natural killer cells in mice sensitized with Toxoplasma lysate antigen before and after Babesia infection

When 8-week-old BALB/c mice were sensitized with two intramuscular injections of Toxoplasma lysate antigen (TLA) at 2 week interval, the numbers of sIg(+), Thy-1,2(+), Lyt-1,2(+) Lyt-2,2(+), and Asialo GM1(ASGM1)(+) cells in the spleen, liver and peripheral blood increased by 2 to 4 times over those found in unsensitized mice of the same age. When TLA-sensitized and unsensitized mice were infected with Babesia, 4 of 10 (40%) of the TLA-sensitized mice survived infection, while none of the unsensitized control mice lived longer than 14 days after Babesia infection. By contrast, sensitization of nude mice with TLA had no effect on survival, and mice did not live more than 12 days. The number of thymic Thy-1,2(+) cells decreased in TLA-sensitized and unsensitized BALB/c mice by almost 80% within 10 days after infection (AI). During the same time, the numbers of B cells, T cells, and NK cells increased in the spleen, liver and peripheral blood of both sensitized and unsensitized mice. Especially notable were increases in numbers of Lyt-2,2(+) cells in the spleen and blood and increases in numbers of NK cells in the spleen, liver and blood in both TLA-sensitized and unsensitized mice. When spleen cells from TLA-sensitized and unsensitized mice were cultured in the presence or absence of TLA for 6 days, assays for cytotoxicity using NK-insensitive P-815 target cells and NK-sensitive YAC-1 target cells demonstrated higher rates of cytotoxicity in cultures of TLA-sensitized spleen cells.     

Biosynthesis of agr-Ecdysone by Prothoracic Glands in vitro

An in vitro study in which isolated prothoracic glands of the Bombyx silkworm were cultured has provided definite evidence that the prothoracic gland is the site where molting hormone is synthesized. The hormone behaved very similarly to free ecdysone on thin-layer chromatography. Analysis by liquid chromatography and mass fragmentography revealed that the hormone is identical with alpha-ecdysone.