Background
—The precise molecular mechanism of Adriamycin-induced cardiomyopathy (ADR-CM) is still unknown. We address the demonstration of apoptotic myocardial cell death and the apoptosis-inducing molecules in ADR-CM induced in rats.
Methods and Results
—Until 8 weeks after the first administration of ADR, there was no increase in the number of labeled cells by terminal deoxynucleotidyl transferase assay (TUNEL method). Apoptotic indices increased significantly at weeks 9 and 10 in hearts of the ADR-treated group but not in those of the control group (0.42±0.12% versus 0.10±0.02% and 0.86±0.11% versus 0.09±0.04% at weeks 9 and 10, respectively). DNA ladder formation was also observed in the myocardial tissues during the late stages of the ADR-CM of rats. There was no significant difference in expression of
p53
gene between the ADR group and the control group at either the message or the protein level. An overexpression of Fas antigen was shown in myocardial cells of ADR-treated hearts at weeks 9 and 10 by both Western blotting and immunofluorescent staining. Furthermore, we confirmed that neutralization of anti–Fas ligand antibody inhibited ADR-induced apoptosis.
Conclusions
—Apoptotic cell death was observed in the hearts of ADR-CM rats, and the number of apoptotic myocardial cells increased with the deterioration of morphological findings and cardiac function, indicating that apoptosis may be an important mechanism of loss of myocardial cells and cardiac dysfunction in ADR-CM. Apoptosis in ADR-CM rats is not p53-dependent but rather is executed through a Fas-mediated pathway.
A novel polysaccharide, here named DP1, was isolated from the fruiting body of Dictyophora indusiata using a water extraction method. Structure characterization revealed that DP1 had an average molecular weight of 1132 kDa and consisted of glucose (56.2%), galactose (14.1%), and mannose (29.7%). The main linkage type of DP1 were proven to be (1 → 3)-linked α-l-Man, (1 → 2,6)-linked α-d-Glc, (1 → 6)-linked β-d-Glc, (1 → 6)-linked β-d-Gal, and (1 → 6)-linked β-d-Man by periodate oxidation-Smith degradation and nuclear magnetic resonance analysis. The immunostimulating assay indicated that DP1 could significantly promote macrophage NO, TNF-α, and IL-6 secretion in murine RAW 264.7 cells involving complement receptor 3 (CR3). The immune activities of DP1 were quite stable under thermal processing (100, 121, and 145 °C). Besides, DP1 retained stability after acidic/alkline treatment (pH 4.0-10.0), which enabled it to be an ideal complementary medicine or functional food for therapeutics of hypoimmunity and immunodeficiency diseases.
The transpeptidase activity of glutaminase from Bacillus amyloliquefaciens (GBA) and Aspergillus oryzae (GAO) to yield γ-[Glu]-Phe peptides were verified for the first time. In the presence of Gln and Phe, γ-Glu-Phe and γ-Glu-γ-Glu-Phe were synthesized by GAO, and γ-Glu-Phe, γ-Glu-γ-Glu-Phe, γ-Glu-γ-Glu-γ-Glu-Phe, γ-Glu-γ-Glu-γ-Glu-γ-Glu-Phe, and γ-Glu-γ-Glu-γ-Glu-γ-Glu-γ-Glu-Phe were synthesized by GBA. The K values for the transpeptidation catalyzed by GBA and GAO were 47.88 and 153.92 mM (Phe as the acceptor), 84.89 and 236.47 mM (γ-Glu-Phe as the acceptor), indicating that GBA had a greater affinity than GAO for Phe and γ-Glu-Phe in the transpeptidation reaction. The K values for the transpeptidation catalyzed by GBA against acceptors, Phe and γ-[Glu]-Phe (47.88-206.47 mM), increased with an elevated number of γ-glutamyl residue within the acceptor. The optimal conditions for γ-[Glu]-Phe synthesis were pH 10 and 37 °C for 3 h, 300 mM Gln, 100 mM Phe, 0.05 U/mL GBA. All the γ-[Glu]-Phe exhibited astringency in water and imparted a kokumi taste to commercial soy sauce and model chicken broth. The astringent threshold values (2.5-3.92 mM) were approximately 3-fold of the kokumi threshold concentrations (0.78-1.53 mM). γ-[Glu]-Phe or the post-enzymatic reaction mixture enhanced the umami intensity of commercial soy sauce and model chicken broth.
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