Nanocomposite packaging regulates extracellular ATP and programed cell death in edible mushroom (Flammulina velutipes)

Universal Near-Infrared Fluorescent Nanoprobes for Detection and Real-Time Imaging of ATP in Real Food Samples, Living Cells, and Bacteria

Adenosine triphosphate (ATP), an essential metabolite for active microorganisms to maintain life activities, has been widely regarded as a marker of cell activity and an indicator of microbial contamination. Herein, we designed two near-infrared (NIR) fluorescent nanoprobes named CYA@ZIF-90 and CYQ@ZIF-90 by encapsulating the NIR dye CYA/CYQ in ZIF-90 for the rapid detection of ATP. Between them, nanoprobe CYA@ZIF-90 can achieve higher NIR emission (702 nm) and rapid detection (2 min). Based on the superior spatiotemporal resolution imaging of ATP fluctuations in living cells, the applicability of CYA@ZIF-90 for imaging and detection of ATP in living bacteria was explored for the first time. The nanoprobe indirectly realizes the quantitative detection of bacteria, and the detection limit can be as low as 74 CFU mL-1. Therefore, the prepared nanoprobe is expected to become a universal ATP sensing detection tool, which can be further applied to evaluate cell apoptosis, cell proliferation, and food-harmful microbial control.

Recent advances in quality preservation of postharvest golden needle mushroom (Flammulina velutiper)

The golden needle mushroom (Flammulina velutiper) is one of the most productive mushrooms in the world. However, F. velutiper experiences continuous quality degradation in terms of changes in color and textural characteristics, loss of moisture, nutrition and flavor, and increased microbial populations due to its high respiratory activity during the postharvest phase. Postharvest preservation techniques, including physical, chemical and biological methods, play a vital role in maintaining postharvest quality and extending the shelf life of mushrooms. Therefore, in this study, the decay process of F. velutiper and the factors affecting its quality were comprehensively reviewed. Additionally, the preservation methods (e.g., low-temperature storage, packaging, plasma treatment, antimicrobial cleaning and 1-methylcyclopropene treatment) for F. velutiper used for the last 5 years were compared to provide an outlook on future research directions. Overall, this review aims to provide a reference for developing novel, green and safe preservation techniques for F. velutiper. © 2023 Society of Chemical Industry.

Transcriptome analysis reveals the potential mechanism of polyethylene packing delaying lignification of Pleurotus eryngii

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Transcriptomics analysis of polyethylene (PE) on lignification of P. eryngii.

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Differentially expressed genes are enriched in process of lignin decomposition.

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PE delayed lignification by regulation of gene related to lignin metabolism.

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Visualization of lignin changes in P. eryngii by confocal Raman microspectroscopy.

Transcriptome analysis is important for the quality improvement of edible fungi, however, the effect of polyethylene (PE) packaging on the preservation of Pleurotus eryngii at the transcriptome level still needs to be further investigated. In order to elucidate the effect of PE on delaying lignification of P. eryngii, this study focused on exploring effects of PE on enzymes and genes involved in lignification. The results showed that PE packaging delayed the deterioration of phenotype, color difference and weight loss rate of P. eryngii, inhibited lignin and H₂O₂ content and maintained firmness and cellulose content. The activities of PAL, POD, 4-CL were inhibited, and more laccase expression was activated. Fifty-five differentially expressed genes associated with laccase, multifunctional peroxidase (VP), POD and 4-CL were screened from 10 d, 20 d and 30 d transcriptome data. These results show that PE could inhibit lignification of P. eryngii by up-regulating laccase and VP related genes involved in lignin decomposition and down-regulating the expression of genes involved in lignin synthesis. Meanwhile, we employed Confocal Raman microspectroscopy (CRM) to realize lignin cell level visualization and PE could reduce lignin deposition and weaken the lignin signal bands formed. Therefore, PE can alleviate the lignification of P. eryngii during storage by regulating the expression of specific genes, advancing the understanding of lignification in postharvest P. eryngii at the molecular level, and CRM has the potential to detect the changes of P. eryngii cell wall.

Effects of the Addition of Dendrobium officinale on Beer Yeast Fermentation

Dendrobium officinale is a precious Chinese medicinal plant that is rich in polysaccharides, flavonoids, polyphenols, and other bioactive ingredients, and has a variety of biological activities. To explore the effects of D. officinale on the growth and metabolism of Saccharomyces cerevisiae, different concentrations (0, 10, 30, 50, and 100 g/L) of fresh D. officinale were added to the wort during the fermentation. The amount of yeast, alcohol content, reducing sugars, total acidity, pH, CO2 loss, and foam height were analyzed. Meanwhile, the glucose uptake, cell viability, key enzyme activity of yeast, total phenolics, antioxidant activity, volatile compounds, and consumer acceptance of brewed samples were also analyzed. The results showed that the growth and metabolism of yeast could be promoted by a suitable dosage of D. officinale but were inhibited at high dosage (100 g/L). The addition of D. officinale increased the activities of glucose-6-phosphate dehydrogenase and alcohol dehydrogenase, while the highest concentration of D. officinale (100 g/L) decreased the glucose uptake and cell activity of the yeast. The contents of total phenolics and esters, along with the scavenging activity against ABTS radicals, were increased, indicating that the antioxidant activity and aromatic characteristics of beer would be improved by the addition of D. officinale.

Gene Expression Analyses of Mutant Flammulina velutipes (Enokitake Mushroom) with Clogging Phenomenon

Regulation of proper gene expression is important for cellular and organismal survival, maintenance, and growth. Abnormal gene expression, even for a single critical gene, can thwart cellular integrity and normal physiology to cause diseases, aging, and death. Therefore, gene expression profiling serves as a powerful tool to understand the pathology of diseases and to cure them. In this study, the difference in gene expression in Flammulina velutipes was compared between the wild type (WT) mushroom and the mutant one with clogging phenomenon. Differentially expressed transcripts were screened to identify the candidate genes responsible for the mutant phenotype using the DNA microarray analysis. A total of 88 genes including 60 upregulated and 28 downregulated genes were validated using the real-time quantitative PCR analysis. In addition, proteomic differences between the WT and mutant mushroom were analyzed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF). Interestingly, the genes identified by these genomic and proteomic analyses were involved in stress response, translation, and energy/sugar metabolism, including HSP70, elongation factor 2, and pyruvate kinase. Together, our data suggest that the aberrant expression of these genes attributes to the mutant clogging phenotype. We propose that these genes can be targeted to foster normal growth in F. velutipes.

Advances in chilling injury of postharvest fruit and vegetable: Extracellular ATP aspects

Due to the global use of cold chain, the development of postharvest technology to reduce chilling injury (CI) in postharvest fruits and vegetables during storage and transport is needed urgently. Considerable evidence shows that maintaining intracellular adenosine triphosphate (iATP) in harvested fruits and vegetables is beneficial to inhibiting CI occurrence. Extracellular ATP (eATP) is a damage-associated signal molecule and plays an important role in CI of postharvest fruits and vegetables through its receptor and subsequent signal transduction under low-temperature stress. The development of new aptasensors for the simultaneous determination of eATP level allows for better understanding of the roles of eATP in a myriad of responses mediated by low-temperature stress in relation to the chilling tolerance of postharvest fruits and vegetables. The multiple biological functions of eATP and its receptors in postharvest fruits and vegetables were attributed to interactions with reactive oxygen species (ROS) and nitric oxide (NO) in coordination with phytohormones and other signaling molecules via downstream physiological activities. The complicated interconnection among eATP in relation to its receptors, eATP/iATP homeostasis, ROS, NO, and heat shock proteins triggered by eATP recognition has been emphasized. This paper reviews recent advances in the beneficial effects of energy handling, outlines the production and homeostasis of eATP, discusses the possible mechanism of eATP and its receptors in chilling tolerance, and provides future research directions for CI in postharvest fruits and vegetables during low-temperature storage.