Production of citrinin-free Monascus pigments by submerged culture at low pH

Microbial fermentation of citrinin-free Monascus pigments is of great interest to meet the demand of food safety. In the present work, the effect of various nitrogen sources, such as monosodium glutamate (MSG), cornmeal, (NH4)(2)SO4, and NaNO3, on Monascus fermentation was examined under different initial pH conditions. The composition of Monascus pigments and the final pH of fermentation broth after Monascus fermentation were determined. It was found that nitrogen source was directly related to the final pH and the final pH regulated the composition of Monascus pigments and the biosynthesis of citrinin. Thus, an ideal nitrogen source can be selected to control the final pH and then the citrinin biosynthesis. Citrinin-free orange pigments were produced at extremely low initial pH in the medium with (NH4)(2)SO4 or MSG as nitrogen source. No citrinin biosynthesis at extremely low pH was further confirmed by extractive fermentation of intracellular pigments in the nonionic surfactant Triton X-100 micelle aqueous solution. This is the first report about the production of citrinin-free Monascus pigments at extremely low pH

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200 hlm. : ilus. ; 30 cm

Dynamic Changes of Cytokine Profiles and Their Correlation With Tumor Recurrence Following Thermal Ablation in Hepatocellular Carcinoma

The 5-year recurrence rate of thermal ablation for hepatocellular carcinoma (HCC) is high, and whether this treatment strategy induces systemic immune response remains elusive. This study aimed to investigate the effects of thermal ablation on HCC patients’ cytokine profiles and to explore the correlation of cytokine profiles with tumor recurrence after ablation. A total of 22 HCC patients were included in this prospective study. The levels of 27 cytokines in the peripheral blood of HCC patients were measured before ablation (baseline), week 1, and week 4 after ablation using a Bio-Plex Pro Human Cytokine 27-plex Assay kit. Cytokines showed different dynamic changing trends after ablation treatment. It was found that the level of IL-6 was significantly elevated at week 1 and returned to the baseline level at week 4 after ablation. The level of IL-10 was slightly reduced at week 1 and significantly decreased at week 4. The levels of MCP-1, macrophage inflammatory protein-1β (MIP-1β), and TNF-α were similarly reduced at week 1 and increased at week 4. The levels of IL-17, platelet-derived growth factor-BB (PDGF-BB), and regulated upon activation, normal T cell expressed and secreted (RANTES) showed little to no change at week 1 while an observable increase at week 4. Patients with a high IL-10 level (2.99 pg/ml) at baseline and low levels of TNF-α (20.4 pg/ml), PDGF-BB (107.78 pg/ml), and RANTES (2303.94 pg/ml) at week 4 were at risk of tumor recurrence during 1-year follow-up. The results suggested that thermal ablation activated systemic immune responses by changing the levels of cytokines. The results also demonstrated that measurement of IL-10 at baseline, TNF-α, PDGF-BB, and RANTES at week 4 after ablation might predict the risk of tumor recurrence