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Three walnut peptides with different molecular masses were prepared from walnut meal protein by sequential enzymatic hydrolysis and ultrafiltration, and separately glycosylated with five sugars (glucose, sucrose, lactose, maltodextrin and dextran). The reaction conditions were optimized based on emulsifying properties and anti-lipid oxidation capacity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectroscopy were used to characterize the glycosylated peptides, their physicochemical properties were studied, and their emulsion stability was determined by laser confocal microscopy (LCM). The results showed that the optimal conditions for the glycosylation reaction between walnut peptide with molecular mass greater than 30 kDa and maltodextrin were as follows: ratio of walnut peptide to maltodextrin 1:2, reaction time 8 h, reaction temperature 80 ℃, and peptide concentration 15 mg/mL. SDS-PAGE confirmed the formation of a covalent complex between the walnut peptide and maltodextrin through glycosylation reaction. FTIR spectroscopy showed that sugar molecules were connected to walnut peptide molecules by covalent bonds. CD spectroscopy showed that the peptide’s structure changed. The proportion of α-helix increased from 4.85% to 6.43%, the proportion of antiparallelism increased from 30.16% to 35.91%, the proportion of parallelism increased from 3.28% to 4.33%, the proportion of β-turn decreased from 23.21% to 20.77%, and the proportion of random coil decreased from 33.59% to 31.22%. The glycosylation modification did not improve the Fe2+ chelating capacity, but increased the solubility, emulsifying capacity to (83.24 ± 1.64) m2/g, emulsion stability to (218.49 ± 3.55) min, water absorption capacity to (3.92 ± 0.36) g/g, oil absorption capacity to (3.17 ± 0.24) g/g, surface hydrophobicity to 251.05 ± 6.91, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity to (86.74 ± 2.14)%, and anti-lipid oxidation capacity to (62.17 ± 3.51)%. The results of LCM showed that the encapsulation capacity of walnut peptides for walnut oil was enhanced after glycosylation, suggesting a potential application for improving the stability of emulsions. The glycosylation modification of walnut peptides provides a new idea for the processing and utilization of walnut meal by-products and provides a reference for the application of glycosylation modification in food development.

Freezing injury in winter is an important abiotic stress that seriously affects plant growth and development. Deciduous fruit trees resist freezing injury by inducing dormancy. However, different cultivars of the same species have different cold resistance strategies. Little is known about the molecular mechanism of apple trees in response to freezing injury during winter dormancy. Therefore, in this study, 1-year-old branches of the cold-resistant cultivar ‘Hanfu’ (HF) and the cold-sensitive cultivar ‘Changfuji No. 2’ (CF) were used to explore their cold resistance through physiological, biochemical, transcriptomics, and metabolomics analyses. Combining physiological and biochemical data, we found that HF had a stronger osmotic regulation ability and antioxidant enzyme activity than CF, as well as stronger cold resistance. The functional enrichment analysis showed that both cultivars were significantly enriched in pathways related to signal transduction, hormone regulation, and sugar metabolism under freezing stress. In addition, the differentially expressed genes (DEGs) encoding galactinol synthase, raffinose synthase, and stachyose synthetase in raffinose family oligosaccharides (RFOs) metabolic pathways were upregulated in HF, and raffinose and stachyose were accumulated, while their contents in CF were lower. HF accumulated 4-aminobutyric acid, spermidine, and ascorbic acid to scavenge reactive oxygen species (ROS). While the contents of oxidized glutathione, vitamin C, glutathione, and spermidine in CF decreased under freezing stress, consequently, the ability to scavenge ROS was low. Furthermore, the transcription factors apetala 2/ethylene responsive factor (AP2/ERF) and WRKY were strongly induced under freezing stress. In summary, the difference in key metabolic components of HF and CF under freezing stress is the major factor affecting their difference in cold resistance. The obtained results deepen our understanding of the cold resistance mechanism in apple trees in response to freezing injury during dormancy.

Melatonin is an important regulator of fruit growth and development. To explore the physiological mechanism whereby preharvest melatonin application regulates the polyphenol content of ‘Yuluxiang’ pear peel, we sprayed 0.1 mM melatonin during the first fruit expansion and early color change periods, and the control group were sprinkled with fresh water. Then, we measured the contents of anthocyanin, lignin, and major monomeric phenolics and the activities of key enzymes associated with phenolic metabolism. The results showed that melatonin application significantly increased the content of total phenolics, total flavonoids, total anthocyanins, and lignin in the peel from the color change to mature development stages. Near maturity, the activities of all key enzymes, except dihydroflavonol-4-reductase, were higher than those in the control samples, but significant differences in enzyme activity occurred at different time points. Compared with the control group, the fruit peels of the melatonin-treated plants exhibited a higher antioxidant activity and accumulated more flavonols. Thus, preharvest spraying of melatonin can alter the activity of key enzymes associated with phenolic metabolism, increasing the total phenol, flavonoid, anthocyanin, and lignin contents, which in turn, affects the color, strength, and antioxidant capacity of pear peels.

Melatonin (MT), an indoleamine compound, has a pleiotropic effect on plant growth and development and can regulate the quality of tree fruit. Systematic research on the effect of preharvest MT spraying on pear fruit quality and technical solutions for MT application to regulate pear fruit quality are still lacking. Thus, here we aimed to evaluate the effects of different spraying times, concentrations, and exogenous MT application times on ‘Yuluxiang’ pear fruit quality. Our results showed that the single fruit weight and vertical and horizontal diameters of pear fruit sprayed with MT twice at 30 and 90 d after full bloom were the largest, and the red and green values of the treatment were the highest. MT-treated pears had higher contents of total soluble solids, soluble sugar, sucrose, sorbitol, fructose, and glucose and lower contents of titratable acid, malic acid, and citric acid. Moreover, exogenous MT treatment increased the pear peel strength. Based on the principal component analysis of 10 fruit quality indices, the suitable periods for MT spraying on ‘Yuluxiang’ pears were 30 and 90 d after full bloom, the suitable concentration was 100 μmol/L, and the suitable number of times was two. This study provides a theoretical reference for optimizing MT application and improving pear fruit quality.

Low temperature is an abiotic stress factor limiting the distribution of fruit tree cultivation areas. As temperate deciduous fruit trees, apple (Malus domestica) trees go dormant in the winter to adapt to or avoid damage caused by low temperatures. The capacity for cold resistance is closely linked to the physiological, biochemical, and structural characteristics of one-year-old branches. In this study, we investigated such changes in the branches of cold-resistant ‘Hanfu’ (HF) and cold-sensitive ‘Naganofuji 2’ (CF) apple varieties. The relative electrical conductivity, malondialdehyde content, and reactive oxygen species content of HF branches were lower than those of CF branches, while the antioxidant enzyme activity was higher in HF. The proline, soluble protein, and soluble sugar contents in both varieties showed an initial increase, followed by a subsequent decrease. Sucrose and sorbitol were the main sugar components, but sucrose and fructose were higher in HF than in CF. The periderm, phloem, and xylem of HF branches were also found to be thicker than those of CF branches, while the vessel diameter was smaller and the density greater. The results of this study provide a theoretical reference for further research on the low temperature adaptability of apple tree branches during dormancy.

We examined the effects of three different soil conditions (orchard soil, cropland soil, unused soil) on the functional diversity of soil microbial communities. The results first showed that orchard and cropland land use significantly changed the distribution and diversity of soil microbes, particularly at surface soil layers. The richness index (S) and Shannon diversity index (H) of orchard soil microbes were significantly higher than the indices of the cropland and unused soil treatments in the 0-10 cm soil layer, while the S and H indices of cropland soil microbes were the highest in 10-20 cm soil layers. Additionally, the Simpson dominance index of cropland soil microbial communities was the highest across all soil layers. Next, we found that carbon source differences in soil layers under the three land use conditions can mainly be attributed to their carbohydrate and polymer composition, indicating that they are the primary cause of the functional differences in microbial communities under different land uses. In conclusion, orchard and cropland soil probably affected microbial distribution and functional diversity due to differences in vegetation cover, cultivation, and management measures.

Apple trees grafted on different rootstock types, including vigorous rootstock (VR), dwarfing interstock (DIR), and dwarfing self-rootstock (DSR), are widely planted in production, but the molecular determinants of tree branch architecture growth regulation induced by rootstocks are still not well known. In this study, the branch growth phenotypes of three combinations of 'Fuji' apple trees grafted on different rootstocks (VR: Malus baccata; DIR: Malus baccata/T337; DSR: T337) were investigated. The VR trees presented the biggest branch architecture. The results showed that the sugar content, sugar metabolism-related enzyme activities, and hormone content all presented obvious differences in the tender leaves and buds of apple trees grafted on these rootstocks. Transcriptomic profiles of the tender leaves adjacent to the top buds allowed us to identify genes that were potentially involved in signaling pathways that mediate the regulatory mechanisms underlying growth differences. In total, 3610 differentially expressed genes (DEGs) were identified through pairwise comparisons. The screened data suggested that sugar metabolism-related genes and complex hormone regulatory networks involved the auxin (IAA), cytokinin (CK), abscisic acid (ABA) and gibberellic acid (GA) pathways, as well as several transcription factors, participated in the complicated growth induction process. Overall, this study provides a framework for analysis of the molecular mechanisms underlying differential tree branch growth of apple trees grafted on different rootstocks.

Small-cell neuroendocrine carcinoma of the cervix (SCNCC) is a rare and aggressive tumor with a poor prognosis. Surgical resection followed by adjuvant therapy is the standard treatment for early-stage disease but the influence of different neo/adjuvant treatment approaches remains unclear. Retrospectively, we collected patients' characteristics and treatments in two medical centers. Disease status and survival outcomes were renewed through follow-up. Statistics analysis mainly included Kaplan-Meier methods for survival curve estimation, log-rank test for survival curve comparison, and Cox proportional hazards models for independent prognostic factors prediction. Finally, 51 patients treated by radical surgery between January 2010 and April 2020 were enrolled with a median age of 50 years (range: 32-68). 12 (23.5%) patients were at stage IIIC1 according to the International Federation of Gynecology and Obstetrics (FIGO) 2018 staging systems and the rest were at the early stage. The mean tumor size was 3.6±1.3 cm. Pathological examination found 24 cases with pure SCNCC and 27 cases with admixed SCCC. 29 (56.9%) patients had deep stromal infiltration and 19 (37.3%) patients had lymphovascular space invasion. 34 (66.7%) patients received neo/adjuvant chemotherapy and pelvic radiation was conducted in 41 (80.39%) patients with a median dose of 46 Gy (range: 40-50.4 Gy). The median follow-up time was 25.0 months. The median disease-free survival (DFS) time was 23.0 months. 27 (52.9%) patients developed distant metastasis and 14 (27.5%) experienced local failure. The median overall survival (OS) was 32.0 months. Univariate and multivariate analysis showed neoadjuvant chemotherapy as negative (HR=2.081, 95% CI 1.030-4.203, p=0.041) and adjuvant chemotherapy (HR=0.409, 95% CI 0.213-0.784, p=0.020) as positive independent prognostic factor for DFS. For OS, only lymph node metastasis was confirmed as an independent prognostic factor in both univariate analysis (HR=1.528, 95% CI 1.011-2.308, p=0.044) and multivariate analysis (HR=1.697, 95% CI 1.041-2.768, p=0.034). In conclusion, for surgically treated SCNCC, adjuvant chemotherapy showed a positive influence on DFS while neoadjuvant chemotherapy harmed DFS. OS was unaffected by either treatment choice. [ABSTRACT FROM AUTHOR]