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During storage, winter jujube often experiences physiological disorders that can result in postharvest quality deterioration. To address this concern, a combination of 1% chitosan (CTS) and varying concentrations (0.02, 0.2, and 2 mg mL-1) of ε-polylysine (ε-PL) was applied. The findings indicated that the treatment involving the combination of 1% CTS with 0.2 mg mL-1ε-PL exhibited superior efficacy in preserving the hardness and titratable acid content of winter jujube. Additionally, the jujube fruits of this treatment exhibited a deceleration in the rise of decay incidence, red index, and weight loss rate. Simultaneously, the application of CTS combined with ε-PL treatment improved the levels of antioxidant enzyme activities (SOD, CAT, POD, and APX) and enhanced contents of antioxidant compounds (AsA and GSH). Moreover, the generation of reactive oxygen species (H2O2 and O2-.) was suppressed. Consequently, CTS combined with ε-PL treatment effectively enhanced postharvest quality and regulated antioxidant status of winter jujube. [ABSTRACT FROM AUTHOR]

The utilization of natural preservatives presents a promising avenue for mitigating the spoilage of fresh-cut fruits and vegetables induced by microorganisms, enzymatic browning, and water loss. We have developed an innovative method for preserving fresh-cut green peppers using the combined effects of ε-polylysine (ε-PL) and p-Coumaric acid (p-CA). Through concentration screening experiments, we determined that the optimal concentrations of ε-PL and p-CA were 25 mg/L and 10 mg/L, respectively (ε-p-CA). Treatment with ε-p-CA significantly improved the quality of fresh-cut green peppers. It effectively reduced hardness and weight loss, preserving the texture and appearance of the peppers. Furthermore, ε-p-CA treatment delayed the increase in respiratory rate, electrolyte leakage, and ethylene production, thereby maintaining the structural integrity. Meanwhile, ε-p-CA treatment effectively inhibited the malondialdehyde (MDA) content increase and maintained DPPH radical scavenging activity. The microbial analysis demonstrated the ε-p-CA-treated peppers also showed lower total bacterial, mold, and yeast counts, which prolonged the freshness of fresh-cut peppers. In addition, ε-p-CA treatment improved the retention of phenolics and vitamin C without significantly affecting the color and soluble sugar content of green peppers. Overall, the ε-p-CA treatment showed promise as a natural preservative for extending the shelf life of fresh-cut green peppers. [ABSTRACT FROM AUTHOR]

Melatonin (MT), as a putative pleiotropic signal molecule, could participate in inducing postharvest disease resistance and inhibiting postharvest pathogen infection in fruit. In this study, we investigate the mechanism of induced resistance by MT treatment against Alternaria rot of jujube. The results showed that 2 and 20 μmol/L MT did not have direct antimicrobial activity, 200 μmol/L MT had little influence on antifungal activity against Alternaria alternata in vitro. MT significantly reduced the lesion area of fruit inoculated with A. alternata. MT decreased the relative electrolytic leakage, malondialdehyde content, hydrogen peroxide, and the rate of superoxide anion production, while enhanced the ascorbic acid and reduced glutathione contents. Furthermore, MT observably increased the defensive enzyme activities of superoxide dismutase, the catalase, ascorbate peroxidase, peroxidase. Accordingly, these results indicated that MT treatment increased the disease resistance of jujube fruit by regulating reactive oxygen species metabolism. Novelty impact statement: The results showed that MT treatment could inhibit the expansion of lesion diameter, reduce the decay rate of winter jujube, and reduce the accumulation of reactive oxygen species by activating the oxidase system, thus enhancing the resistance of winter Jujube fruit to Alternaria alternata infection by adjusting the ROS mechanism. [ABSTRACT FROM AUTHOR]

The K+ transporter/high-affinity K+/K+ uptake (KT/HAK/KUP) transporters dominate K+ uptake, transport, and allocation that play a pivotal role in mineral homeostasis and plant adaptation to adverse abiotic stresses. However, molecular mechanisms towards K+ nutrition in forest trees are extremely rare, especially in willow. In this study, we identified 22 KT/HAK/KUP transporter genes in purple osier willow (designated as SpuHAK1 to SpuHAK22) and examined their expression under K+ deficiency, drought, and salt stress conditions. Both transcriptomic and quantitative real-time PCR (qRT-PCR) analyses demonstrated that SpuHAKs were predominantly expressed in stems, and the expression levels of SpuHAK1, SpuHAK2, SpuHAK3, SpuHAK7, and SpuHAK8 were higher at the whole plant level, whereas SpuHAK9, SpuHAK11, SpuHAK20, and SpuHAK22 were hardly detected in tested tissues. In addition, both K+ deficiency and salt stress decreased the tissue K+ content, while drought increased the tissue K+ content in purple osier plant. Moreover, SpuHAK genes were differentially responsive to K+ deficiency, drought, and salt stresses in roots. K+ deficiency and salt stress mainly enhanced the expression level of responsive SpuHAK genes. Fifteen putative cis-acting regulatory elements, including the stress response, hormone response, circadian regulation, and nutrition and development, were identified in the promoter region of SpuHAK genes. Our findings provide a foundation for further functional characterization of KT/HAK/KUP transporters in forest trees and may be useful for breeding willow rootstocks that utilize potassium more efficiently. [ABSTRACT FROM AUTHOR]

Due to the existence of viral reservoirs, the rebound of human immunodeficiency virus type 1 (HIV-1) viremia can occur within weeks after discontinuing combined antiretroviral therapy. Immunotherapy could potentially be applied to eradicate reactivated HIV-1 in latently infected CD4+ T lymphocytes. Although the existence of HIV-1-specific CD8+ T memory stem cells (TSCMs) is well established, there are currently no reports regarding methods using CD8+ TSCMs to treat HIV-1 infection. In this study, we quantified peripheral blood antigen-specific CD8+ TSCMs and then expanded HIV-1-specific TSCMs that targeted optimal antigen epitopes (SL9, IL9, and TL9) in the presence of interleukin- (IL-) 21 or IL-15. The suppressive capacity of the expanded CD8+ TSCMs on HIV-1 production was measured by assessing cell-associated viral RNA and performing viral outgrowth assays. We found that the number of unmutated TL9-specific CD8+ TSCMs positively correlated with the abundance of CD4+ T cells and that the expression of IFN-γ was higher in TL9-specific CD8+ TSCMs than that in non-TL9-specific CD8+ TSCMs. Moreover, the antiviral capacities of IL-21-stimulated CD8+ TSCMs exceeded those of conventional CD8+ memory T cells and IL-15-stimulated CD8+ TSCMs. Thus, we demonstrated that IL-21 could efficiently expand HIV-1-specific CD8+ TSCMs to suppress HIV-1 replication. Our study provides new insight into the function of IL-21 in the in vitro suppression of HIV-1 replication. [ABSTRACT FROM AUTHOR]

Theeffect of carboxymethyl cellulose and alginate coating combinedwith brewer yeast on postharvest grape preservation was investigated. Thepostharvest grapeswere coatedwith2%of alginate and3%of carboxymethyl cellulose combined with 1.5 × 109 CFU/mL of brewer yeast.The combined treatment samples showed good sensory character on day 13 compared with control samples or only coated samples. The increase of weight loss and decrease of total soluble solids of combined treatment grapes were restrained. Furthermore, the protective enzymes including superoxide dismutase, peroxidase, and catalase of combined treatment sample showed higher activities.Accordingly, the increase ofmalonaldehyde contentwas also restrained andmore vitamin Cwas preserved in combined treatment samples. At day 13, the weight loss rate and the total soluble solids of grape treated with coating + yeast were 23.6% lower and 20.6% higher than those of control samples, respectively. Coating grapes with 2% of alginate and 3% of carboxymethyl cellulose combined with brewer yeast of 1.5 × 109 CFU/mL was a well-proven method to preserve postharvest grapes. [ABSTRACT FROM AUTHOR]