•Three new compounds were isolated from cultures of the fungus Xylaria polymorpha.•The structures were elucidated by NMR and X-ray diffraction analysis.•Two new compounds showed weak inhibitory activity against acetylcholinesterase.Three new drimane-type sesquiterpenoids named xylariaines A–C (1–3), together with one known analogue (4), were isolated from the ethyl acetate extract of cultures of the fungus Xylaria polymorpha (Pers.: Fr.) Grer. Their structures were elucidated unambiguously by NMR and single-crystal X-ray diffraction analysis. Compounds 1 and 2 exhibited weak anti-acetylcholinesterase activities at a concentration of 50 μg/mL with inhibition ratios of 12.4% and 18.0%, respectively.Download high-res image (119KB)Download full-size image

•The proteome of peach-purified mitochondria was investigated using the method of 2-DE.•Proteins showed interesting expression patterns under different storage temperature.•Some proteins only expressed in 25 °C or 4 °C during storage.•Some antioxidative enzymes showed relatively important symptoms on ROS scavenging.•Expressions of energy metabolism proteins increased significantly during storage.Ripening and senescence define the last step of fruit development, which directly affects its commercial value, and mitochondria play a crucial role in these processes. To better understand mitochondrial roles in maintaining and regulating metabolism in storage tissues, highly purified mitochondria were isolated from peach tissues (Prunus persica. cv. Xiahui-8) stored at 4 °C and 25 °C, respectively, and their proteome was conducted using the method of 2-DE and MALDI-TOF/TOF. Twenty-four (24) differentially expressed proteins (2-fold, p ≤ 0.01) were identified out of more than 300 spots and were divided into six categories by PIR and Uniprot, including oxidative stress (34%), carbon metabolism (29%), respiratory chain (17%), amino acid metabolism and protein biosynthesis (8%), heat shock protein (4%), ion channels (4%). Proteins involved in antioxidative systems, gluconeogenesis, glycolysis, ethanol fermentation were changed significantly in response to high temperature. Storage at 4 °C dramatically delayed ripening and senescence processes by postponing the climacteric peak, slowing down carbon metabolism and degradation of cell structure. Besides, low temperature induced the expression of formate dehydrogenase and some amino acid metabolism proteins. Proteins classified in respiratory chain, ion channels showed high coherence with climacteric respiratory burst, and the antioxidative enzymes showed relatively important symptoms on ROS scavenging through orderly expressions.SignificanceWith the advent of proteomics and mass spectrometry (MS), it becomes possible to identify the specific functions of differentially abundant proteins in peach mitochondria. In the present study, a procedure to isolate mitochondria from peach fruits was established, and the mitochondrial proteome was systematically analyzed by 2-D gel electrophoresis procedures in combination with protein identification by mass spectrometry. Differentially expressed proteins in peach mitochondria during different stages of peach fruit ripening and senescence were characterized. Our data provide a great deal of information likely to enhance the understanding of the mitochondrial function in peach ripening and senescent process during storage.

Lignification is one of the most crucial factors affecting the edible value of the stem of wild Pteridium aquilinum. To investigate the probable mechanism of lignification, the changes in protein profiles in the stem of wild P. aquilinum during its development were investigated by means of two-dimensional electrophoresis technology. The two-dimensional electrophoresis results revealed that there were twenty-seven differential proteins, twenty-four proteins of which were identified by MALDI-TOF/TOF. We classified these twenty-four proteins into six functional categories: photosynthesis (8, 33.3 %); respiratory metabolism (4, 16.7 %); stress response and defence (6, 25.0 %); cell structure (1, 4.2 %); phenylpropanoid metabolism (4, 16.6 %) and unclassified protein (1, 4.2 %). According to the functional analysis of these differentially expressed proteins, we concluded that photosynthesis was enhanced during P. aquilinum’s development and sugars generated from photosynthesis were partially metabolized through the glycolysis pathway and phosphopentose pathway, respectively, thus producing the precursors for lignin biosynthesis. The up-regulation of caffeoyl-CoA-O-methyl-transferase and SAM synthetase in abundance and the down-regulation of chalcone synthase can be directly responsible for lignification during stem development. This experiment is useful for understanding the biochemical mechanisms of the lignification process of P. aquilinum during its development.

•This is the first proteomic study involving postharvest leaf vegetables.•A proteomic approach was used to study the effect of 1-MCP on G. bicolor.•1-MCP decelerated the metabolism of G. bicolor leaf and enhanced its defense.•1-MCP promoted gene transcription, translation and protein expression.•1-MCP and ethylene exerted opposite effects on maintain the integrity of cells.Proteins were extracted from G. bicolor that had been treated with 1-methylcyclopropene and ethephon and then stored at room temperature for 1, 3 and 7 days. More than 300 protein spots were detected by 2-DE and 38 differentially abundant spots (P < 0.05) were excised and analysed by using MALDI-TOF/TOF. Thirty-three proteins were finally confidently identified. According to the Clusters of Orthologous Groups of proteins, the proteins identified were classified into those responsible for metabolism (75.8%), information storage and processing (9.1%) and cellular processes and signaling (12.1%). Compared with ethephon and control treatments, 1-methylcyclopropene specifically increased the abundances of superoxide dismutase, peroxidase, carbonic anhydrase, nucleoside diphosphate kinases, glyceraldehyde 3-phosphate dehydrogenase, RuBisCO and ribulose bisphosphate carboxylase/oxygenase activase. 1-Methylcyclopropene protected leaf chloroplast and cells by enhancing stress response and defense, and delayed senescence by inhibiting substance and energy metabolisms. Therefore, 1-methylcyclopropene allowed better self-defense and delayed senescence of G. bicolor leaf.

•O2− and H2O2 may play potential signaling roles during peach fruit development.•Accumulated H2O2 induces oxidative stress during peach fruit ripening.•Function of PpaSODs is involved with their metal factor and subcellular localization.•PpaCAT1 and PpaGPX6 are two key members in response to oxidative stress.The roles of reactive oxygen species (ROS) as both toxic by-products and as signaling molecules have been reported in fruit development and ripening. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) play important roles in balancing the induction and removal of ROS in plants, and are respectively encoded by families of closely homologous genes. In the present study, we investigated the roles of ROS and the above-mentioned antioxidant genes during the development and ripening of peach fruit. The experimental results indicated that O2− and H2O2 acted as potential signaling molecules in the middle stage of fruit development, and only H2O2 might function as a main toxic molecule to stimulate lipid peroxidation and oxidative stress in the late stage of fruit ripening. PpaCu/Zn-SODs were the most abundant members in the PpaSOD gene family and they expressed steadily in peach fruit development and ripening. Low temperature (4 °C) postponed and suppressed the climacteric peaks of respiration and ethylene, significantly enhanced the activities of CAT and GPX, and up-regulated the expression of PpaCAT1 and PpaGPX6 in the late stage of fruit ripening. PpaCAT1 and PpaGPX6 were two key genes in alleviating oxidative stress in the late stage of fruit ripening.Download full-size image

Aroma, a complex mixture of volatile compounds, plays an important role in the perception and acceptability of tomato products by consumers. Numerous studies have reported volatile profiles in tomatoes based on measurement of the whole fruit or pericarp tissue, however, little is understood regarding the volatile compositions in the inner tissues. The objective of this study was to investigate the differences in volatile profile between pericarp tissue and locular gel in tomato fruit. Based on HS-SPME-GC-MS analysis, totally 42 volatile compounds were detected in FL 47 and Tasti-Lee tomato fruits. Regardless of cultivars, a substantial higher concentration of total volatile compounds was observed in pericarp than that in locular gel, associated with higher levels of aldehydes, hydrocarbons, and nitrogen compounds. Pericarp tissue possessed higher levels of cis-3-hexenal, hexanal, heptanal, octanal, nonanal, cymene, terpinolene, undecane, dodecane, 2-phenylethanol, 6-methyl-5-hepten-2-one, 2-methylbutyl acetate, 1-nitro-pentane, and 1-nitro-2-phenylethane, while the abundances of 2-methylpropanal, butanal, 2-methylbutanal, 2-methyl-2-butenal, 2-methylpropanol, 3-methylbutanol, 2-methylbutanol, and 2-butanone were higher in locular gel. Principal component analysis (PCA) and cluster analysis using GC-MS and electronic nose (E-nose) data discriminated the two tissues.

•Heat treatment had positive effect on peach fruit quality during cold storage.•Heat water treatment was more effective in alleviating chilling injury than heat air.•Antioxidant system in peach fruit was easier to be affected by heat water treatment.•AsA-GSH cycle might play an important role in maintaining the low H2O2 content.Peach fruit are susceptible to chilling injury (CI) during low temperature storage. In this study, the effect of hot air (HA, 38 °C for 3 h) and hot water (HW, 48 °C for 10 min) treatments on CI, fruit quality, reactive oxygen species (ROS) and antioxidants in peach fruit during storage at 4 °C was investigated. The results indicated that HA or HW treatments maintained fruit quality, decreased Reactive oxygen species (ROS) and enhanced antioxidants activity of fruit. However, HW was more effective than HA in alleviating internal browning (IB) symptoms in fruit. HW treatment may be easier to affect the antioxidant system in peach fruit due to the higher heat transmission in water. HA treatment had no effect on either AsA metabolism or GSH metabolism. However, HW enhanced the AsA metabolism in the early stage of storage and the GSH metabolism in the late stage of storage. Enhanced AsA-GSH metabolism and up-regulated expressions of PpaSOD5, PpaCAT1 and PpaAPX2 in the HW treated fruit might play an important role in maintaining the lower ROS level and IB index during refrigerated storage.