Activation of the toll-like receptor 2 signaling pathway by GAPDH from bacterial strain RD055328.

We characterized the membrane vesicle fraction (RD-MV fraction) from bacterial strain RD055328, which is related to members of the genus Companilactobacillus and Lactiplantibacillus plantarum. RD-MVs and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were detected in the RD-MV fraction. Immunoglobulin A (IgA) was produced by Peyer's patch cells following the addition of the RD-MV fraction. In the presence of the RD-MV fraction, RAW264 cells produced the pro-inflammatory cytokine IL-6. Recombinant GAPDH probably induced the production of IL-6 by RAW264 cells via superficial toll-like receptor 2 (TLR2) recognition. A confocal laser scanning microscopy image analysis indicated that RD-MVs and GAPDH were taken up by RAW264 cells. GAPDH wrapped around RAW264 cells. We suggest that GAPDH from strain RD055328 enhanced the production of IgA by acquired immune cells via the production of IL-6 by innate immune cells through TLR2 signal transduction.

Anti-osteoporotic effects of syringic acid and vanilic acid in the extracts of waste beds after mushroom cultivation.

In recent years, the number of patients with osteoporosis has increased as population grows older. Therefore, the chemoprevention of osteoporosis by better nutrition is important. White-rot fungi degrades milled wood lignin for growth and development. This degradation results in the formation of phenolic compounds such as syringic acid (SA) and vanillic acid (VA). In the artificial culture of edible mushrooms using a mushroom bed, the disposal of waste beds after mushroom cultivation is an important issue. The present study investigated the presence and amount of both SA and VA in the discarded waste beds after mushroom cultivation. The extracts from waste beds after cultivation of shiitake mushrooms, Lentinula edodes; buna shimeji, Hypsizygus marmoreus; maitake, Grifola frondosa; king trumpet mushrooms, Pleurotus eryngii; and butterscotch mushrooms, Pholiota microspora were analyzed using high performance liquid chromatography. Although the content of SA and VA was considerably different among the mushrooms, SA and VA were present in extracts obtained from all the waste beds. We also demonstrated that SA and VA exert their anti-osteoporotic effect independently of the estrogen receptor-mediated pathway using murine monocytic RAW264.7 cells, ovariectomized mice, and human breast cancer MCF-7 cells. Thus, these results suggest that the extracts are effective sources of SA and VA, which are effective in preventing osteoporosis.

Antiosteoporotic activity of a syringic acid diet in ovariectomized mice.

In recent years, the number of patients with osteoporosis has risen with the increase in average longevity. Therefore, the chemoprevention of osteoporosis using food materials or food components has become an increasingly important target. Syringic acid (SA) is a phenolic compound present in the fruit of the açaí palm Euterpe oleracea and the mycelium of the shiitake mushroom Lentinula edodes. This compound has no affinity for estrogen receptors and is potentially useful for disease prevention. However, little is known about the effects of a SA diet on bone metabolism, particularly bone resorption in vivo. Here, we demonstrated the effects of a SA diet on bone loss and uterine weight loss in ovariectomized (OVX) mice. Ten-week-old OVX mice were fed SA-containing diets (100 mg/kg body weight/day) for 10 weeks. After 10 weeks of dietary SA, the body weight, food intake, and uterine weight of the OVX mice were unaffected; however, femoral bone mineral density (cortical bone density, cancellous bone density, and total bone density) was higher in the SA-fed groups than in the OVX-control group. Furthermore, histomorphometric analysis revealed that the number of osteoclasts and osteoblasts was decreased and increased, respectively, in the SA-fed groups. These results suggest that a SA diet suppresses bone loss by downregulating bone resorption and upregulating bone formation without affecting the uterus in OVX mice. Although further studies are needed, SA may be a compound that can be used to prevent or retard osteoporosis.

Mutational and crystallographic analysis of l-amino acid oxidase/monooxygenase from Pseudomonas sp. AIU 813: Interconversion between oxidase and monooxygenase activities.

In this study, it was shown for the first time that l-amino acid oxidase of Pseudomonas sp. AIU813, renamed as l-amino acid oxidase/monooxygenase (l-AAO/MOG), exhibits l-lysine 2-monooxygenase as well as oxidase activity. l-Lysine oxidase activity of l-AAO/MOG was increased in a p-chloromercuribenzoate (p-CMB) concentration-dependent manner to a final level that was five fold higher than that of the non-treated enzyme. In order to explain the effects of modification by the sulfhydryl reagent, saturation mutagenesis studies were carried out on five cysteine residues, and we succeeded in identifying l-AAO/MOG C254I mutant enzyme, which showed five-times higher specific activity of oxidase activity than that of wild type. The monooxygenase activity shown by the C254I variant was decreased significantly. Moreover, we also determined a high-resolution three-dimensional structure of l-AAO/MOG to provide a structural basis for its biochemical characteristics. The key residue for the activity conversion of l-AAO/MOG, Cys-254, is located near the aromatic cage (Trp-418, Phe-473, and Trp-516). Although the location of Cys-254 indicates that it is not directly involved in the substrate binding, the chemical modification by p-CMB or C254I mutation would have a significant impact on the substrate binding via the side chain of Trp-516. It is suggested that a slight difference of the binding position of a substrate can dictate the activity of this type of enzyme as oxidase or monooxygenase.