The involvement of phenolic metabolism in superficial scald development in ‘Wujiuxiang’ pear

Superficial scald often occurs after a long term of cold storage in apples and pears. In this study, the superficial scald index, the contents of major phenolic compounds, polyphenol oxidase (PPO) activity and its related genes expression in peel was investigated during cold storage period and at shelf life in ‘Wujiuxiang’ pear (Pyrus communis L. cv. Wujiuxiang) with or without 1-MCP treatment. It showed that arbutin, chlorogenic acid, catechin and epi-catechin were the main phenolic compounds in the peel, and 1-MCP treatment significantly inhibited scald development while altering the composition of phenolic compounds, inhibited PPO activity and the expression of phenylalanine ammonia ligase (PAL1, PAL2), cinnamate 4-hydroxylase (C4H1, C4H2) and PPO (PPO1, PPO5) and up-regulated the expression of hydroxycinnamoyl-CoA shikimate/quinate hydroycinnamoyltransferase (HCT1), p-coumarate-3-hydro-xylase (C3H) and PPO (PPO4 and PPO6) in the peel. These results suggested that the phenolic metabolism is closely related to the scald development, and several genes related to phenolic metabolism were involved in scald development

The influence of 1-MCP on the fruit quality and flesh browning of ‘Red Fuji’ apple after long-term cold storage

This study assessed the influence of 1-MCP treatment on the fruit quality and flesh browning of ‘Red Fuji’ apple at shelf life after long-term cold storage. The ‘Red Fuji’ fruit were stored at 0±0.5 °C for 270 days after treating with 1.0 μL L-1 1-methylcyclopropylene (1-MCP). Fruit quality, browning rate of stem-end flesh, chlorogenic acid content, polyphenol oxidase (PPO) activity were analyzed at shelf-life under 20±0.5 °C, the expression profile of ethylene receptors (MdERS1), phenylalnine ammonia lyase genes (MdPA L1, MdPA L2), quinate hydroxycinnamoyl/hydrxycinnamoyl CoA shi-kimate gene (MdHCT3), polyphenol oxidase genes (MdPPO1, MdPPO5)and lipoxygenase gene (MdLOX) were measured by real-time quantitative PCR. 1-MCP treatment improved the fruit storage quality, decreased stem-end flesh tissue browning, and fruit decay. In addition, the fruit respiration rate and ethylene production rate increased at shelf-life, but this increase could be inhibited by 1-MCP. The same rule was observed in the changes of chlorogenic acid content and PPO activity, the expression of MdERS1, MdPA L1, MdPPO1 and MdLOX were inhibited by 1-MCP as well in the stem-end flesh. Thus, 1-MCP treatment improves the fruit quality of ‘Red Fuji’ apple at shelf-life after long-term cold storage, and inhibits the browning of stem-end flesh by decreasing the chlorogenic acid content and PPO activity. MdPA L1, MdHCT3, MdPPO1 and MdLOX participate in the flesh browning progress

Different response to 1-methylcyclopropene in two cultivars of Chinese pear fruit with contrasting softening characteristics

In this study, the change in softening and its related genes expression under influence of 500 nl L-1 1-methylcyclopropene (1-MCP) was assessed in the two Chinese pear fruit, ‘Jingbaili’ (Pyrus ussuriensis Maxim) and ‘Yali’ (Pyrus bretschneideri Rehd), which exhibit different softening characteristics. ‘Jingbaili’ pear fruit softened rapidly after harvest, and was strongly inhibited by 1-MCP. In contrast, there was no obvious change of firmness compared to the control after 1-MCP treatment in ‘Yali’ pear fruit. The respiration and ethylene production rates were reduced by 1-MCP at early storage in both two cultivars. ‘Jingbaili’ pear fruit exhibited dramatically increased expression levels of the softening-related genes, i.e., polygalacturonase1 (PG1), polygalacturonase2 (PG2), β-Galactosidase4 (GAL4), α-arabinofuranosidase1 (ARF1) and α-arabinofuranosidase2 (ARF2), and these genes’ expression levels were significantly decreased by 1-MCP treatment. In contrast, ‘Yali’ pear fruit showed lower expression levels of the above-mentioned genes, as well as a relatively smaller inhibition effect by 1-MCP treatment before day 27. These results suggest that ‘Jingbaili’ pear fruit are more sensitive to 1-MCP/ethylene than ‘Yali’ pear fruit during ripening

Effect of Preharvest Aminoethoxyvinylglycine Treatment on Fruit Quality and Core Browning in ‘Huangguan’ Pear after Long-Term Cold Storage

In order to prolong the storage period of ‘Huangguan’ pear and reduce the deterioration of fruit quality during long-term storage and subsequent shelf life, this study conducted preharvest treatment with different concentrations of aminoethoxyvinylglycine (AVG) to ‘Huangguan’ pear. Before and after refrigeration for 180 days and after subsequent shelf life for 7 days, quality indicators were tested. The results showed that compared with the control group, preharvest AVG treatment delayed the decline of fruit firmness, maintained higher contents of soluble solids and titratable acids, and effectively inhibited fruit surface browning and core browning, the most pronounced effect being observed at 200 mg/L AVG. During long-term cold storage, the contents of arbutin, chlorogenic acid and total phenols increased with the occurrence of core browning, and the activity of polyphenol oxidase (PPO) increased. The expression levels of PbPAL1, PbPAL2, PbPPO1, PbPPO5, PbLOX1 and PbLOX5 were up-regulated during cold storage, but down-regulated during shelf life. Preharvest treatment with 200 mg/L AVG significantly reduced the consumption of arbutin, chlorogenic acid and total phenols, inhibited the increase of PPO activity along with the expression of PbPAL1, PbPAL2, PbPPO1, PbPPO5 and PbLOX5, and thus effectively reduced core browning in ‘Huangguan’ pear

What is impact of nonsteroidal anti-inflammatory drugs in the prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis: a meta-analysis of randomized controlled trials

Abstract Background Recently, although studies have investigated the role of NSAIDs in the prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP), selection of the ideal drug, the time and route of its administration for the appropriate population remain controversial. Methods A systematic search was done in sources including PubMed, Embase, Web of Science, the Cochrane Library Central, and ClinicalTrials.gov from from August 1, 1990 to August 1, 2017. Randomized controlled trials comparing the prophylactic use of NSAIDs versus a placebo were included. Statistical analysis was performed using the RevMan 5.3 software to assess the outcomes. Results A total of 21 randomized controlled trials were included in the meta-analysis. Our study showed that NSAIDs significantly reduced the incidence of PEP (RR, 0.61, 95%CI,0.52–0.72; p < 0.00001). The analysis showed that indomethacin administration post-ERCP (RR, 0.47; 95% CI, 0.31–0.70; p = 0.0002) appeared to be more effective in preventing PEP than indomethacin administration pre-ERCP (RR, 0.59; 95% CI, 0.45–0.79; P = 0.0003), but there was no significant difference between the high-risk and average-risk population(p = 0.13). In the diclofenac group, it was noted that administration of diclofenac pre-ERCP (RR, 0.32; 95% CI, 0.16–0.63; p = 0.001) was more effective than that in post-ERCP (RR, 0.65; 95% CI, 0.27–1.599; p = 0.35). The relative risk of PEP was 0.63 (95% CI, 0.27–1.50; p = 0.30) in high-risk patients and 0.41 (95% CI, 0.17–0.98; p = 0.02) in average-risk patients. With regard to the route of administration, PEP decreased significantly only in patients receiving the drug rectally (RR, 0.53; 95% CI, 0.44–0.63; p < 0.00001), but not for those who received intramuscularly (RR, 0.74; 95% CI, 0.47–1.17; p = 0.20), intravenously (RR, 0.97; 95% CI, 0.51–1.83; p = 0.93), and orally (RR = 0.88; 95% CI, 0.55–0.1.43; p = 0.62). Conclusions Rectal administration of NSAIDs (both indomethacin and diclofenac) was effective in preventing PEP in unselected patients. A single dose of indomethacin after ERCP might be effective in preventing PEP in both high-risk and average-risk patients. However, diclofenac administered rectally before ERCP might be protective against PEP in high-risk patients compared to a placebo. However, more high quality head-to-head RCTs are required

Effects of Preharvest Aminoethoxyvinylglycine (AVG) Treatment on Fruit Ripening, Core Browning and Related Gene Expression in ‘Huangguan’ Pear (<i>Pyrus bretschneideri</i> Rehd.)

‘Huangguan’ pear (Pyrus bretschneideri Rehd. cv. Huangguan) is a widely planted cultivar in China. However, it is susceptible to core browning after harvest. In this study, aminoethoxyvinylglycine (AVG) was applied at 200 mg L−1 one and two weeks prior to harvest, and its effects on fruit quality, ripening and core browning were investigated during fruit storage at ambient temperature (25 ± 1 °C). The results showed that there was higher firmness, soluble solids content (SSC) and titratable acid (TA) content, but a lower ethylene production rate and core browning index in AVG-treated fruit than in control (water). Compared with the control fruit, AVG treatment decreased the malondialdehyde (MDA) content and polyphenol oxidase (PPO) activity, delayed the peak of chlorogenic acid (CGA) content in the core tissue, and significantly inhibited the expression of genes such as ACC synthase (PbACS2, PbACS3a, PbACS5a and PbASC5b), ACC oxidase (PbACO1 and PbACO2), ethylene receptors (PbETR2 and PbERS1), ethylene response factor (PbERF1), phenylalanine ammonia lyase (PbPAL1), cinnamate 4-hydroxylase (PbC4H4), 4-hydroxycinnamoyl- CoA ligase (Pb4CL2), hydroxycinnamoyl- CoA shikimate hydroxycinnamoyl transferase (PbHCT1 and PbHCT3), and polyphenol oxidase (PbPPO1 and PbPPO5), as well as phospholipase D (PbPLD) and lipoxygenase (PbLOX1 and PbLOX5). Thus, these results suggested that the reduction in core browning by preharvest application of AVG might be due to an inhibitory effect on the expression of genes associated with ethylene biosynthesis and signaling pathways, CGA biosynthesis, PPO and cell membrane degradation in ‘Huangguan’ pear

Low Temperature Conditioning Reduced the Chilling Injury by Regulating Expression of the Dehydrin Genes in Postharvest Huangguan Pear (<i>Pyrus bretschneideri</i> Rehd. cv. Huangguan)

‘Huangguan’ pear (Pyrus bretschneideri Rehd. cv. Huangguan) fruit is sensitive to chilling injury (CI), which exhibits peel browning spots (PBS) during cold storage. Dehydrin (DHN) is considered to be related to cold tolerance in plants, but its function in postharvest pear fruit during storage remains unclear. In this study, six PbDHNs (PbDHN1–6) genes were identified and characterized, and the PbDHN proteins were sorted into YnKn, SKn and YnSKn according to the major conserved motifs related to the number and location of K-segments, S-segments, and Y-segments. In addition, there were five cold-responsive related cis-acting elements in the promoter region of the PbDHNs. The analysis of fruit quality suggested that compared with a storage temperature at 20 °C, a storage temperature of 0 °C results in CI in ‘Huangguan’ pear fruit, while a storage temperature of 10 °C and low temperature conditioning (LTC) alleviates the CI. Moreover, gene expression results indicated that the six PbDHNs were markedly enhanced at low temperatures, especially at 0 °C. The transcripts of PbDHN1, PbDHN4, PbDHN5 and PbDHN6 were also increased in the fruit stored at 10 °C, but they were lower than that at 0 °C except PbDHN5. Compared with low temperature storage at 0 °C, LTC treatment significantly depressed the expression of PbDHN1, PbDHN2, PbDHN3, PbDHN4, and PbDHN6, while enhanced the mRNA amount of PbDHN5. In conclusion, PbDHN1, PbDHN4, PbDHN5, and PbDHN6 were closely related to the CI, and LTC lowered the CI by down-regulating the expression of PbDHN1, PbDHN4, and PbDHN6 and by up-regulating PbDHN5 in ‘Huangguan’ pear fruit

Optofluidics Refractometers

Refractometry is a classic analytical method in analytical chemistry and biosensing. By integrating advanced micro- and nano-optical systems with well-developed microfluidics technology, optofluidics are shown to be a powerful, smart and universal platform for refractive index sensing applications. This paper reviews recent work on optofluidic refractometers based on different sensing mechanisms and structures (e.g., photonic crystal/photonic crystal fibers, waveguides, whisper gallery modes and surface plasmon resonance), and traces the performance enhancement due to the synergistic integration of optics and microfluidics. A brief discussion of future trends in optofluidic refractometers, namely volume sensing and resolution enhancement, are also offered