Storage Quality Variation of Mushrooms (<i>Flammulina velutipes</i>) after Cold Plasma Treatment

Flammulina velutipes is susceptible to mechanical damage, water loss, microbial growth, and other factors that lead to postharvest deterioration, thereby shortening the storage period. The purpose of this study was to analyze the effects of cold plasma treatment on the physicochemical properties and antioxidant capacity of F. velutipes during storage at 4 °C for 21 days. Compared to the control group, cold plasma cold sterilization (CPCS) treatment (150 Hz, 95 kV for 150 s) effectively inhibited the growth and multiplication of microorganisms on the surface of F. velutipes, with no significant effect on the fresh weight change and the superoxide anion generation rate, but with a higher postharvest 1,1-dephenyl-2-picrylhydrzyl (DPPH) clearance rate. Moreover, CPCS increased antioxidant enzyme activities, delayed both malondialdehyde (MDA) accumulation and vitamin C loss, inhibited the browning reaction and polyphenol oxidases (PPO) activity and protected F. velutipes cell membrane from disruption. In general, CPCS not only achieved bacteriostatic effects on F. velutipes during storage, but also reduced cell damage from free radical oxidation, resulting in better postharvest quality and longer shelf life

Efficient In Vitro TRAIL-Gene Delivery in Drug-Resistant A2780/DDP Ovarian Cancer Cell Line via Magnetofection

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) presents great promise as an anticancer agent for human cancer therapy. In this study, a magnetofection agent (polyMAG-l000) was evaluated for in vitro delivery of TRAIL gene towards drug-resistant A2780/DDP ovarian cancer cells. Transfection experiments showed that polyMAG-l000 was able to transfect A2780/DDP cells in vitro, leading to a higher level of TRAIL gene expression in the presence of a static magnetic field as compared to other transfection agent, such as Lipofectamine 2000. TRAIL gene expression in the A2780/DDP cells was also confirmed by Western blot analysis. Moreover, the TRAIL gene expression exhibited remarkable decrease in the cell viability, as determined by MTT assay. Importantly, PolyMAG-l000-mediated TRAIL gene transfection in the presence of anticancer drug cisplatin (CDDP) induced much higher percentages of apoptotic A2780/DDP cells, compared to TRAIL gene transfection or CDDP treatment alone. A further study by Western blot analysis indicated that cytochrome c release and caspase-9 cleavage pathway were associated with the initiation of the apoptosis in A2780/DDP cells. The results of this study indicate that polyMAG-l000 can be used as an efficient agent for TRAIL gene transfection in ovarian cancer cells

Site-Specific Biomimetic Precision Chemistry of Bimodal Contrast Agent with Modular Peptides for Tumor-Targeted Imaging

Various biomimetic nanoparticles have been fabricated for cancer nanotheranostics with a diverse range of proteins. However, the operating mechanisms of these reactions are still unclear, especially on the interaction between metal ions and protein, the precise binding sites, and the existence format of nanoparticles. Assuming the shortening of the amino acids sequence into several, namely short peptides, it would be much easier to investigate the biomimetic reaction mechanism. In this study, a modular peptide, possessing Au³⁺ ion coordination motifs and a Gd³⁺ ion chelation sequence, is designed and synthesized. This peptide is experimentally found effective in site-specific biomimetic synthesis of paramagnetic fluorescent gold nanoclusters (pAuNCs) with a quantum yield of 6.8%, deep red emission at 676 nm, and potent relaxivity. The gel electrophoresis result declares that the two imaging motifs in pAuNCs are quite stable. In vivo fluorescence–magnetic resonance bimodal imaging show significant tumor enhancement by pAuNCs in tumor-bearing mice. In vivo biodistribution and toxicity studies reveal that pAuNCs can be gradually cleared from the body without damage. This study presents a modular peptide that can incubate multifunctional nanoparticles in a biomimetic fashion and hopefully provides a strategy for the investigation of the mechanism of protein-mediated biomimetic synthesis

Proteomic Investigation of Metabolic Changes of Mushroom (<i>Flammulina velutipes</i>) Packaged with Nanocomposite Material during Cold Storage

Metabolic changes of mushroom (<i>Flammulina velutipes</i>) applied with polyethylene (PE) material (Normal-PM) or nanocomposite reinforced PE packaging material (Nano-PM) were monitored using tandem mass tags (TMT) labeling combined with two-dimensional liquid chromatography-tandem mass spectrometry (2D LC-MS/MS) technique. A total of 429 proteins were investigated as differentially expressed proteins (DEPs) among treatments after a cold storage period. A total of 232 DEPs were up-regulated and 65 DEPs were down-regulated in Nano-PM packed <i>F. velutipes</i> compared to that of Normal-PM. The up-regulated DEPs were mainly involved in amino acid synthesis and metabolism, signal transduction, and response to stress while the down-regulated DEPs were largely located in mitochondrion and participated in carbohydrate metabolic, amino acid synthesis and metabolism, and organic acid metabolic. It was also revealed that Nano-PM could inhibit the carbohydrate and energy metabolism bioprocess, promote amino acids biosynthesis, enhance antioxidant system, and improve its resistance to stress, resulting in a further extended shelf life of <i>F. velutipes</i>

Development of Efficient Chemistry to Generate Site-Specific Disulfide-Linked Protein– and Peptide–Payload Conjugates: Application to THIOMAB Antibody–Drug Conjugates

Conjugation of small molecule payloads to cysteine residues on proteins via a disulfide bond represents an attractive strategy to generate redox-sensitive bioconjugates, which have value as potential diagnostic reagents or therapeutics. Advancement of such “direct-disulfide” bioconjugates to the clinic necessitates chemical methods to form disulfide connections efficiently, without byproducts. The disulfide connection must also be resistant to premature cleavage by thiols prior to arrival at the targeted tissue. We show here that commonly employed methods to generate direct disulfide-linked bioconjugates are inadequate for addressing these challenges. We describe our efforts to optimize direct-disulfide conjugation chemistry, focusing on the generation of conjugates between cytotoxic payloads and cysteine-engineered antibodies (i.e., THIOMAB antibody–drug conjugates, or TDCs). This work culminates in the development of novel, high-yielding conjugation chemistry for creating direct payload disulfide connections to any of several Cys mutation sites in THIOMAB antibodies or to Cys sites in other biomolecules (e.g., human serum albumin and cell-penetrating peptides). We conclude by demonstrating that hindered direct disulfide TDCs with two methyl groups adjacent to the disulfide, which have heretofore not been described for any bioconjugate, are more stable and more efficacious in mouse tumor xenograft studies than less hindered analogs