Jing Dai,Zhuqian Xiao,Jiajie Li,Qing Ge,Hongpeng Wang,Ruyi Sha,Jianwei Mao
Summary In this study, crude polysaccharide (BSSP) was extracted from bamboo ( Phyllostachys edulis ) shoot shell using the ultrasonic-assisted phosphotungstic acid hydrolysis method. Then, BSSP was further fractionated by DEAE Sepharose fast flow column and serial NaCl solution elutions to obtain two fractions, BSSP-A and BSSP-B. The results showed that the maximum yield of BSSP was 195.2 mg g −1 (19.52%) under optimised conditions. Structural analysis indicated that both BSSP-A and BSSP-B were heteropolysaccharides with α-pyranoside bond structure and mainly consisted of xylose by scanning electronic microscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, thermal characterisation and nuclear magnetic resonance spectroscopy. BSSP-B showed a better protective effect than BSSP-A against H 2 O 2 -induced oxidative injury in WRL-68 cells by protecting the cell membrane structure, maintaining mitochondrial membrane potential and increasing intracellular antioxidant enzymes activities. Immunoblotting indicated that polysaccharides might up-regulate the expression of antioxidant enzymes through the Keap1/Nrf2 signalling pathway and thus alleviate H 2 O 2 -induced cell injury. The findings of this study suggested that polysaccharides from bamboo shoot shell may act as potent antioxidants in functional food industries.
Metabolic dysregulation is a key driver of cellular senescence, contributing to the progression of systemic aging. The heterogeneity of senescent cells and their metabolic shifts are complex and unexplored. A microfluidic SlipChip integrated with surface-enhanced Raman spectroscopy (SERS), termed SlipChip-SERS, is developed for single-cell metabolism analysis. This SlipChip-SERS enables compartmentalization of single cells, parallel delivery of saponin and nanoparticles to release intracellular metabolites and to realize SERS detection with simple slipping operations. Analysis of different cancer cell lines using SlipChip-SERS demonstrated its capability for sensitive and multiplexed metabolic profiling of individual cells. When applied to human primary fibroblasts of different ages, it identified 12 differential metabolites, with spermine validated as a potent inducer of cellular senescence. Prolonged exposure to spermine can induce a classic senescence phenotype, such as increased senescence-associated β-glactosidase activity, elevated expression of senescence-related genes and reduced LMNB1 levels. Additionally, the senescence-inducing capacity of spermine in HUVECs and WRL-68 cells is confirmed, and exogenous spermine treatment increased the accumulation and release of H 2 O 2 . Overall, a novel SlipChip-SERS system is developed for single-cell metabolic analysis, revealing spermine as a potential inducer of senescence across multiple cell types, which may offer new strategies for addressing ageing and ageing-related diseases.
危险品化学品经营许可证（带存储）