In this study, we investigated cooked hams to understand the relationship between display life and quality changes, as well as the microbiological characteristics of refrigerated storage for up to 90 days. Initially, the L* and a* values exhibited an initial decline with a gradual restitution to levels insignificantly disparate from those Day 15 hams. In contrast, the b* and h° values demonstrated an ascending pattern, indicating an augmentation in yellow intensity during the storage. Furthermore, there was an observable escalation in the C* value following 45 days of storage, implying an amplified luminosity and vividness of color during the latter phase of the storage period. Analyses of TBARS , TVB-N, and other physicochemical indexes indicated that the hams underwent deterioration during storage. Whereas, UV–vis and fluorescence spectroscopy illustrated that the pigment in cooked hams changed from nitrosylheme (NO-heme) to Zn-protoporphyrin IX (ZnPP) during storage. The NO-heme content decreased from 41.08 ± 0.44 to 12.76 ± 0.29 mg/kg, while the ZnPP content increased from 12.19 ± 0.41 to 89.44 ± 1.57 mg/kg. The structure of the bacterial community in the ham samples changed over the storage period. Towards the end of the shelf life, the microbial population was dominated by Lactic acid bacteria (LAB), particularly Latilactobacillus (34.91%) and Leuconostoc (19.73%). Redundancy analysis and Pearson correlation revealed a positive correlation between Latilactobacillus and Leuconostoc with TBARS , TVB-N, ZnPP content, and negative correlations with Aw and NO-heme.
He Qingbin,Zheng Runxiao,Ma Junchi,Zhao Luyang,Shi Yafang,Qiu Jianfeng
Background The activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) signaling pathway has attracted great attention for its ability to up-regulate innate immune response and thus enhance cancer immunotherapy. However, many STING agonists limit the further advancement of immunotherapy due to weak tumor responsiveness or low activation efficiency. The responsive and effective activation of cGAS-STING signaling in tumors is a highly challenging process. Methods In this study, a manganese-based nanoplatform (MPCZ NPs) was constructed that could responsively and efficiently generate more manganese ions (Mn 2+ ) and reactive oxygen species (ROS) to activate cGAS-STING signaling pathway. Briefly, manganese dioxide (MnO 2 ) was loaded with zinc protoporphyrin IX (ZPP) molecule and coated by polydopamine (PDA) embedded with NH 4 HCO 3 to obtain MPCZ NPs. Additionally, MPCZ NPs were evaluated in vitro and in vivo for their antitumor effects by methyl thiazolyl tetrazolium (MTT) assay and TUNEL assays, respectively. Results In this system, tumor responsiveness was achieved by exogenous (laser irradiation) and endogenous (high levels GSH) stimulation, which triggered the collapse or degradation of PDA and MnO 2 . Moreover, the release of Mn 2+ augmented the cGAS-STING signaling pathway and enhanced the conversion of hydrogen peroxide (H 2 O 2 ) to hydroxyl radical (·OH) under NIR laser irradiation. Furthermore, the release of ZPP and the elimination of GSH by MPCZ NPs inhibited HO-1 activity and prevented ROS consumption, respectively. Conclusions This adopted open source and reduce expenditure strategy to effectively generate more ROS and Mn 2+ to responsively activate cGAS-STING signaling pathway, providing a new strategy for improving immunotherapy.
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