Influences of two transport strategies on AMPK-mediated metabolism and flesh quality of shrimp (Litopenaeus vannamei).

BACKGROUND: Water-free transportation (WFT), as a novel strategy for express delivery of live shrimp (Litopenaeus vannamei), was developed recently. However, air exposure during this transportation arouses a series of abiotic stress to the shrimp. In the present study, the influences of WFT stress on glycolysis and lipolysis metabolism and meat quality (umami flavor and drip loss) were investigated in comparison with conventional water transportation (WT). RESULTS: The results showed that type II muscle fibers with the feature of anaerobic metabolism were dominated in shrimp flesh. In addition, the increments of intracellular Ca2+ was detected in WFT and WT, which then activated the AMP-activated protein kinase pathway and promoted the consumption of glycogen, as well as the accumulation of lactate and lipolysis, under the enzymolysis of hexokinase, pyruvate kinase, lactate dehydrogenase and adipose triglyceride lipase. Glycogen glycolyzed to latate. Meanwhile, ATP degraded along with glycolysis resulting in the generation of ATP-related adenosine phosphates such as inosine monophosphate with umami flavor and phosphoric acid. More remarkable (P < 0.05) physiological changes (except lactate dehydrogenase and lactate) were observed in WFT compared to WT. Additionally, the fatty acid profile also slightly changed. CONCLUSION: The transport stress induced significant energy metabolism changes of shrimp flesh and therefore effected the flesh quality. The intensifications of freshness (K-value) of shrimp flesh were detected as a result of ATP degradation, which were more pronounced after WFT. However, the drip loss of shrimp flesh was more significantly increased (P < 0.05) after WFT compared to WT. © 2023 Society of Chemical Industry.

Impacts of long-time transportation on whiteleg shrimp (Penaeus vannamei) muscle quality and underlying biochemical mechanisms.

BACKGROUND: Shrimp is widely consumed around the world. Since muscle is the primary edible component of shrimp, muscle quality (particularly texture) has a direct impact on the economic value of shrimp products. However, reports on the shrimp muscle quality influenced by transportation are rather limited, and the underlying mechanism remains unknown. RESULTS: During the simulated transportation, the water pH and total ammonia-nitrogen content and un-ionized ammonia contents were elevated. Furthermore, reductions in shrimp muscle water-holding capacity, hardness, and shear value with intensive myofibrillar protein degradation were detected. Simulated transportation decreased the pH and glycogen content of shrimp muscle while increasing lactic dehydrogenase activity and lactate content, resulting in an elevated level of free calcium ions and increased µ-calpain and general proteolytic activities. Water exchange could improve the water quality and reduce the mortality of shrimp during transportation, as well as decrease muscle textural softening by alleviating these stress responses. CONCLUSIONS: Maintaining water quality and, in particular, reducing ammonia are critical to improving shrimp survival and muscle quality during live transportation. This study is of great significance for the better maintenance of the textural properties of shrimp meat. © 2023 Society of Chemical Industry.

Transcriptional regulation of KCS gene by bZIP29 and MYB70 transcription factors during ABA-stimulated wound suberization of kiwifruit (Actinidia deliciosa).

BACKGROUND: Our previous study has demonstrated that the transcription of AchnKCS involved in suberin biosynthesis was up-regulated by exogenous abscisic acid (ABA) during the wound suberization of kiwifruit, but the regulatory mechanism has not been fully elucidated. RESULTS: Through subcellular localization analysis in this work, AchnbZIP29 and AchnMYB70 transcription factors were observed to be localized in the nucleus. Yeast one-hybrid and dual-luciferase assay proved the transcriptional activation of AchnMYB70 and transcriptional suppression of AchnbZIP29 on AchnKCS promoter. Furthermore, the transcription level of AchnMYB70 was enhanced by ABA during wound suberization of kiwifruit, but AchnbZIP29 transcription was reduced by ABA. CONCLUSIONS: Therefore, it was believed that ABA enhanced the transcriptional activation of AchnMYB70 on AchnKCS by increasing AchnMYB70 expression. On the contrary, ABA relieved the inhibitory effect of AchnbZIP29 on transcription of AchnKCS by inhibiting AchnbZIP29 expression. These results gave further insight into the molecular regulatory network of ABA in wound suberization of kiwifruit.

Exogenous ABA promotes aroma biosynthesis of postharvest kiwifruit after low-temperature storage.

MAIN CONCLUSION: Exogenous ABA played a positive role in the accumulation and biosynthesis of aroma components of postharvest kiwifruit after low-temperature storage, especially the esters production during ripening. Low-temperature storage (LTS) generally affects the aroma formation associated with the decrease in aroma quality in kiwifruit. In this work, abscisic acid (ABA) treatment after LTS increased the production of aroma components in postharvest kiwifruit and enhanced the related enzyme activity, especially alcohol acyltransferase (AAT), branched amino acid transaminase (BCAT) and hydroperoxide lyase (HPL). Corresponding to the enzyme activity, the gene expression of AchnAAT, AchnADH, AchnBCAT and AchnHPL was significantly up-regulated by ABA. The principal component analysis further illustrated the differences in aroma components between ABA and the control. The positive correlation of aroma accumulation with the expression levels of AchnPDC and AchnLOX and the enzyme activities of BCAT and pyruvate decarboxylase (PDC) was also revealed by correlation analysis. In addition, the promoter sequences of the key genes involved in aroma biosynthesis contained multiple cis-elements (ABRE and G-box) of ABA-responsive proteins. Combining the transcriptome sequencing data, the promoting role of ABA signaling in the regulation of aroma biosynthesis of postharvest kiwifruit after LTS was discussed. This study would provide a reference for improving aroma quality of postharvest kiwifruit after LTS, as well the molecular mechanism of kiwifruit aroma fading after LTS.

Exogenous 24-epibrassinolide activates detoxification enzymes to promote degradation of boscalid in cherry tomatoes.

BACKGROUND: Boscalid is often used to extend the storage time of postharvest cherry tomato. Pesticide residue has become an issue of food safety. This study sought to investigate the spatial distribution of boscalid residue in cherry tomato fruits and to determine the effect of 24-epibrassinolide (EBR) in promoting boscalid degradation. RESULTS: Boscalid could quickly penetrate into cherry tomatoes, but mainly remained in the peel. The migration of boscalid from the peel into the core was a time-consuming and complex process during storage. After 72 h, boscalid residues in the pulp and the core began to accumulate gradually. The exogenous application of EBR activated peroxidase, glutathione reductase and glutathione S-transferase, and effectively promoted the degradation of boscalid by a maximum decrease of 44.8% in peel, 54.0% in pulp and 71.2% in core. CONCLUSION: As one of the common pesticides, boscalid had a strong ability to enter the cherry tomato and thus become a potential risk for public consumption. Therefore, rational use of pesticides is recommended. The results of this study indicate that the possible risk of boscalid residue could be alleviated by EBR pretreatment through activating detoxification enzymes. © 2020 Society of Chemical Industry.

ABF2 and MYB transcription factors regulate feruloyl transferase FHT involved in ABA-mediated wound suberization of kiwifruit.

Suberin is a cell-wall biopolymer with aliphatic and aromatic domains that is synthesized in the wound tissues of plants in order to restrict water loss and pathogen infection. ω-hydroxyacid/fatty alcohol hydroxycinnamoyl transferase (FHT) is required for cross-linking of the aliphatic and aromatic domains. ABA is known to play a positive role in suberin biosynthesis but it is not known how it interacts with FHT. In this study, the kiwifruit (Actinidia chinensis) AchnFHT gene was isolated and was found to be localized in the cytosol. Transient overexpression of AchnFHT in leaves of Nicotiana benthamiana induced massive production of ferulate, ω-hydroxyacids, and primary alcohols, consistent with the in vitro ability of AchnFHT to catalyse acyl-transfer from feruloyl-CoA to ω-hydroxypalmitic acid and 1-tetradecanol. A regulatory function of four TFs (AchnABF2, AchnMYB4, AchnMYB41, and AchnMYB107) on AchnFHT was identified. These TFs localized in the nucleus and directly interacted with the AchnFHT promoter in yeast one-hybrid assays. Dual-luciferase analysis indicated that AchnABF2, AchnMYB41, and AchnMYB107 activated the AchnFHT promoter while AchnMYB4 repressed it. These findings were supported by the results of transient overexpression in N. benthamiana, in which AchnABF2, AchnMYB41, and AchnMYB107 induced expression of suberin biosynthesis genes (including FHT) and accumulation of suberin monomers, whilst AchnMYB4 had the opposite effect. Exogenous ABA induced the expression of AchnABF2, AchnMYB41, AchnMYB107, and AchnFHT and induced suberin monomer formation, but it inhibited AchnMYB4 expression. In addition, fluridone (an inhibitor of ABA biosynthesis) was found to counter the inductive effects of ABA. Activation of suberin monomer biosynthesis by AchnFHT was therefore controlled in a coordinated way by both repression of AchnMYB4 and promotion of AchnABF2, AchnMYB41, and AchnMYB107.

Effects of Exogenous Abscisic Acid on Bioactive Components and Antioxidant Capacity of Postharvest Tomato during Ripening.

Abscisic acid (ABA) is a phytohormone which is involved in the regulation of tomato ripening. In this research, the effects of exogenous ABA on the bioactive components and antioxidant capacity of the tomato during postharvest ripening were evaluated. Mature green cherry tomatoes were infiltrated with either ABA (1.0 mM) or deionized water (control) and stored in the dark for 15 days at 20 °C with 90% relative humidity. Fruit colour, firmness, total phenolic and flavonoid contents, phenolic compounds, lycopene, ascorbic acid, enzymatic activities, and antioxidant capacity, as well as the expression of major genes related to phenolic compounds, were periodically monitored. The results revealed that exogenous ABA accelerated the accumulations of total phenolic and flavonoid contents; mostly increased the contents of detected phenolic compounds; enhanced FRAP and DPPH activity; and promoted the activities of PAL, POD, PPO, CAT, and APX during tomato ripening. Meanwhile, the expressions of the major genes (PAL1, C4H, 4CL2, CHS2, F3H, and FLS) involved in the phenylpropanoid pathway were up-regulated (1.13- to 26.95-fold) in the tomato during the first seven days after treatment. These findings indicated that ABA promoted the accumulation of bioactive components and the antioxidant capacity via the regulation of gene expression during tomato ripening.

The oxidative stress and antioxidant responses of Litopenaeus vannamei to low temperature and air exposure.

Low temperature and air exposure were the key attributes for waterless transportation of fish and shrimp. In order to investigate the oxidative stress and antioxidant responses of the live shrimp Litopenaeus vannamei in the mimic waterless transportation, live shrimp were cooled at 13 °C for 3 min, stored in oxygen at 15 °C for 12 h, and then revived in water at 25 °C. The survival rate of shrimp under this waterless transportation system was over 86.67%. The ultrastructure of hepatopancreas cells were observed while activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione peroxidase (GSH-Px), antisuperoxide anion free radicals (ASAFR), total antioxidant capacity (TAOC), reactive oxygen species (ROS) production, content of malondialdehyde (MDA) and relative mRNA expressions of CAT and GSH-Px in the hemolymph and hepatopancreas were determined. Slight distortions of some organelles in hepatopancreas cells was reversible upon the shrimp revived from the cold shock. The activities of SOD, POD, CAT, GSH-Px, TAOC, ROS production and relative mRNA expressions of CAT and GSH-Px increased following the cold shock and reached peak levels after 3 or 6 h of storage, and then decreased gradually. There was no significant difference between the fresh and the revived shrimp in SOD, POD, GSH-Px, TAOC, ROS, MDA and relative mRNA expressions of CAT and GSH-Px. The oxidative stress and antioxidant responses were tissue-specific because hepatopancreas seemed to have a greater ability to defend against organelle damage and was more sensitive to stress than hemolymph based on the results of SOD activity, MDA content and GSH-Px mRNA expression. These results revealed that low temperature and air exposure caused significant oxidative and antioxidant responses, but did not lead to irreversible damages in this waterless system.

High oxygen facilitates wound induction of suberin polyphenolics in kiwifruit.

BACKGROUND: Rapid wound healing would be critical for successful long-term storage of fruits and vegetables. However, there was no direct evidence for the requirement and efficiency of oxygen in the fruit wound-healing process. This study was conducted to investigate the role of oxygen in wound-induced suberization by analyzing melanin, suberin polyphenolics (SPPs) and related enzymes in half-cut kiwifruits exposed to 100%, 50%, 21% and 0% oxygen. RESULTS: By 3 days after wounding, the wound surface of kiwifruit in high (50 and 100%) oxygen appeared as a continuous layer of melanin and SPPs underneath, which effectively prevent excessive water vapor loss from the fruit halves. In contrast, melanin and SPPs deposition in the wound surface in 0% oxygen was significantly reduced, with high water vapor loss. Rapid decrease of soluble phenolic acids (caffeic, p-coumaric, ferulic acids) was coupled with the increase of bound ferulic acid (coniferyl diacetate) especially in high oxygen by 9 days after wounding. Meanwhile, high oxygen enhanced peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase activities. CONCLUSION: Oxygen is required for wound-induced melanin and SPPs formation, and high oxygen is effective in promoting wound suberization in postharvest kiwifruit. © 2017 Society of Chemical Industry.

Suppression of Cell Wall Degrading Enzymes and their Encoding Genes in Button Mushrooms (Agaricus bisporus) by CaCl2 and Citric Acid.

Fresh button mushrooms (Agaricus bisporus) were harvested and treated with a solution of 1.5% CaCl2 + 0.5% citric acid and stored for 16 days at 12 °C. The effects of this treatment on firmness, weight, color, cell wall compositions (cellulose and chitin) and cell wall degrading enzymes (cel1ulase, beta-1, 3 glucanase, chitinase and phenylalanine ammonialyase) were investigated during post-harvest storage. The expressions of major genes (Cel1, Glu1, Chi1 and PAL1) involved in cell wall degradation during post-harvest storage were also monitored. The results revealed that the post-harvest chemical treatment maintained better firmness, weight, color and inhibited cellulase, beta-1, 3 glucanase, chitinase and phenylalanine ammonialyase activities. These findings showed that the down-regulation of cell wall degrading enzymes is a possible mechanism that delays the softening of button mushrooms by the application of combined chemical treatment.

Transcriptome profiling of postharvest strawberry fruit in response to exogenous auxin and abscisic acid.

MAIN CONCLUSION: Auxin and abscisic acid regulate strawberry fruit ripening and senescence through cross-talk of their signal transduction pathways that further modulate the structural genes related to physico-chemical properties of fruit. The physiological and transcriptomic changes in harvested strawberry fruits in responses to IAA, ABA and their combination were analyzed. Exogenous IAA delayed the ripening process of strawberries after harvest while ABA promoted the postharvest ripening. However, treatment with a combination of IAA and ABA did not slow down nor accelerate the postharvest ripening in the strawberry fruits. At the molecular level, exogenous IAA up regulated the expressions of genes related to IAA signaling, including AUX/IAA, ARF, TOPLESS and genes encoding E3 ubiquitin protein ligase and annexin, and down regulated genes related to pectin depolymerization, cell wall degradation, sucrose and anthocyanin biosyntheses. In contrast, exogenous ABA induced genes related to fruit softening, and genes involved in signaling pathways including SKP1, HSPs, CK2, and SRG1. Comparison of transcriptomes in responses to individual treatments with IAA or ABA or the combination revealed that there were cooperative and antagonistic actions between IAA and ABA in fruit. However, 17% of the differentially expressed unigenes in response to the combination of IAA and ABA were unique and were not found in those unigenes responding to either IAA or ABA alone. The analyses also found that receptor-like kinases and ubiquitin ligases responded to both IAA and ABA, which seemed to play a pivotal role in both hormones' signaling pathways and thus might be the cross-talk points of both hormones.

Involvement of three annexin genes in the ripening of strawberry fruit regulated by phytohormone and calcium signal transduction.

KEY MESSAGE: Three annexin genes may be involved in the ripening progress of strawberry fruit. Phytohormones and calcium regulate the expressions of three annexin genes during strawberry fruit ripening. Plant annexins are multi-functional membrane- and Ca(2+)-binding proteins that are involved in various developmental progresses and stress responses. Three annexins FaAnn5a, FaAnn5b and FaAnn8 cDNA obtained from strawberry fruit encode amino acid sequences of approximately 35 kDa containing four annexin repeats, Ca(2+)-binding site, GTP-binding motif, peroxidase residue, and conserved amino acid residues of tryptophan, arginine and cysteine. During fruit development, the transcript levels of FaAnn5a and FaAnn5b increased while FaAnn5b declined after 3/4R stage. The expression patterns of annexins suggested their potential roles in strawberry fruit development and ripening. Expressions of annexin genes were also highly correlated with hormone levels. In addition, exogenous abscisic acid (ABA) enhanced the expressions of FaAnn5a and FaAnn8 while exogenous auxin (IAA) retarded it. However, both ABA and IAA promoted the transcript levels of FaAnn5b, indicating the independent regulation of annexins in fruit likely due to multi-functions of their large family. The responses of annexin genes to exogenous ABA and IAA inhibitors verified the involvement of annexins in plant hormone signaling. Besides, calcium restrained the expressions of FaAnn5s (FaAnn5a and FaAnn5b) but promoted the expression of FaAnn8. Effects of calcium and ethylene glycol tetraacetic acid (EGTA) on the transcript levels of annexins confirmed that calcium likely mediated hormone signal transduction pathways, which helped to elucidate the mechanism of calcium in fruit ripening. Therefore, FaAnn5s and FaAnn8 might be involved in plant hormones' regulation in the development and ripening of strawberry fruit through calcium signaling in the downstream.

Evidence of programmed cell death induced by reconditioning after cold stress in cucumber fruit and possible involvement of ethylene.

BACKGROUND: Cucumber fruit is susceptible to chilling injury (CI), which could be accelerated significantly with subsequent shelf-life. This type of CI culminates in deterioration of organs and eventually leads to cell death. In this study, evidence of programmed cell death (PCD), involving cell death induced by cold stress, was investigated in cucumber. Harvested cucumber (Cucumis sativus L. cv. Zhexiu-1) fruits were stored at 2 °C for 3, 6 or 9 days and subsequently transferred to 20 °C for 2 days. RESULTS: Significant cell death acceleration was observed upon reconditioning after 9 days' cold stress when the hallmark of PCD - DNA laddering - was clearly observed. Further evidence of nuclear DNA cleavage was confirmed by the in situ TdT-mediated dUTP nick end labeling (TUNEL) assay. Chromatin condensation and nucleus distortion were observed by nuclear staining of DPI. Ethylene burst was observed upon reconditioning after 9 days of consecutive cold stress. CONCLUSION: The features of PCD process induced by reconditioning after cold stress in cucumber fruit may be mainly attributed to ethylene burst.

Maturity-dependent chilling tolerance regulated by the antioxidative capacity in postharvest cucumber (Cucumis sativus L.) fruits.

BACKGROUND: The aim of the present study was to reveal the effect of fruit maturity on the chilling tolerance of cucumber (Cucumis sativus L.) fruit and the oxidative and antioxidative mechanisms involved. Chinese mini-cucumber (cv. Hangcui-1) fruits were harvested at four developmental stages: Immature (3-8 days after anthesis (DAA)), Mature (9-16 DAA), Breaker (17-22 DAA) and Yellow (35-40 DAA). All fruits were stored at 2 °C for 9 days and rewarmed at 20 °C for 2 days. RESULTS: The chilling injury index declined with advancing fruit maturity. High superoxide anion radical production rate and hydrogen peroxide content were observed in Immature fruits after cold storage and rewarming. Under chilling stress, superoxide dismutase showed an early response. Fruits at earlier maturity stages exhibited higher catalase, ascorbate peroxidase and monodehydroascorbate reductase activities and glutathione content as well as its redox state, and lower peroxidase, dehydroascorbate reductase and glutathione reductase activities and ascorbate content as well as its redox state. CONCLUSION: Fruits at the earlier developmental stage are more susceptible to chilling injury, which is related to increased oxidative stress. High peroxidase activity and ascorbate content and maintenance of the latter's redox state appear critical to the chilling tolerance of cucumber fruits at later developmental stages.

The spatial distribution and migration of three typical fungicides in postharvest satsuma mandarin (Citrus unshiu Marc.) fruit.

Fungicides are often used to extend the storage time of postharvest satsuma mandarin fruit. In recent years, fungicide residue has become an issue of food safety. This study aimed to investigate the distribution and migration of three typical fungicides (imazalil, prochloraz, thiophanate-methyl) in postharvest satsuma mandarins using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three fungicides could quickly penetrate satsuma mandarins and their gradient concentrations of residues in the fruit were: carpopodium > mesocarp > epicarp > pulp. However, the residues of three fungicides in the edible pulp were obviously lower than the maximum residue limit (MRL = 5.0 mg/kg in China). Residues of the three fungicides decreased in epicarp and carpopodium but increased in mesocarp and pulp during storage. Fungicides could quickly penetrate the fruit, settling primarily in the carpopodium but little in the pulp. Both epicarp and carpopodium were the breakthrough pathways for the fungicides entering the fruit, while epicarp was the main route for the penetration of fungicides. These findings shed new information on the behavior of fungicides and the safety issue of satsuma mandarins.

Tandem Mass Tag Proteomics Provides Insights into the Underlying Mechanism of Flesh Quality Degradation of Litopenaeus vannamei during Refrigerated Waterless Transport at 12 °C.

Refrigerated waterless transport at 12 °C of live shrimp (Litopenaeus vannamei) causes flesh quality deterioration, and the underlying mechanism remains unknown. Herein, proteomics and bioinformatics analyses were used to elucidate the molecular mechanism of flesh quality changes. The result showed that 33 and 44 of the differentially abundant proteins (DAPs) were, respectively, identified in the acute cold (AC) group and the combined stress of acute cold and waterless duration (AC+WD) group, which were mostly involved in the metabolism processes and cellular structure of animal tissues, and notably enriched in biological pathways such as lysosome, glycolysis/gluconeogenesis, and focal adhesion. Furthermore, the changes in color and texture properties were closely associated with tubulin, gelsolin, laminin, trypsin-1, dipeptidyl peptidase, triosephosphate isomerase, and aldehyde dehydrogenase. Therefore, these DAPs could be used as potential biomarkers to monitor the deterioration of shrimp flesh quality during refrigerated waterless transportation.

Physicochemical and functional properties of the protein-starch interaction in Chinese yam.

Protein-starch interaction has an important impact on the properties of starchy foods rich in protein, but the contribution of the interaction to Chinese yam still remains unclear. This study aimed to characterize the physicochemical and functional properties related to the possible interaction between starch and protein in Chinese yam. Differential scanning calorimetry and rapid viscosity analyzer results revealed that the gelatinization temperature increased in protein and starch cross-linked powder, while the peak viscosity and the setback viscosity decreased. The swelling power and solubility at 80°C and 95°C decreased with increasing protein ratio in the powder. In vitro starch digestibility test indicated that a high protein ratio could rapidly reduce digestible starch, but increase both slowly digestible starch and resistant starch. Protein could act as the physical barrier toward starch against heating and digestion to exert the influence on starch properties. Fourier transform infrared spectroscopy test revealed the interaction between protein and starch. These results revealed the role of protein-starch interaction and provided beneficial information for the utilization of Chinese yam.

Participation of FaTRAB1 Transcription Factor in the Regulation of FaMADS1 Involved in ABA-Dependent Ripening of Strawberry Fruit.

Abscisic acid (ABA) plays a crucial role in regulating the ripening of non-climacteric strawberry fruit. In the present study, ABA was confirmed to promote strawberry ripening and induce the down-regulation of FaMADS1. The transient silence of FaMADS1 in strawberries promoted fruit ripening and induced the content of anthocyanin and soluble pectin but reduced firmness and protopectin through a tobacco rattle virus-induced gene silencing technique. In parallel with the accelerated ripening, the genes were significantly induced in the transiently modified fruit, including anthocyanin-related PAL6, C4H, 4CL, DFR, and UFGT, softening-related PL and XTH, and aroma-related QR and AAT2. In addition, the interaction between FaMADS1 and ABA-related transcription factors was researched. Yeast one-hybrid analysis indicated that the FaMADS1 promoter could interact with FaABI5-5, FaTRAB1, and FaABI5. Furthermore, dual-luciferase assay suggested that FaTRAB1 could actively bind with the FaMADS1 promoter, resulting in the decreased expression of FaMADS1. In brief, these results suggest that the ABA-dependent ripening of strawberry fruit was probably inhibited through inhibiting FaMADS1 expression by the active binding of transcript FaTRAB1 with the FaMADS1 promoter.

Wounding induces suberin deposition, relevant gene expressions and changes of endogenous phytohormones in Chinese yam (Dioscorea opposita) tubers.

Wounds on Chinese yam (Dioscorea opposita ) tubers can ocurr during harvest and handling, and rapid suberisation of the wound is required to prevent pathogenic infection and desiccation. However, little is known about the causal relationship among suberin deposition, relevant gene expressions and endogenous phytohormones levels in response to wounding. In this study, the effect of wounding on phytohormones levels and the expression profiles of specific genes involved in wound-induced suberisation were determined. Wounding rapidly increased the expression levels of genes, including PAL , C4H , 4CL , POD , KCSs , FARs , CYP86A1 , CYP86B1 , GPATs , ABCGs and GELPs , which likely involved in the biosynthesis, transport and polymerisation of suberin monomers, ultimately leading to suberin deposition. Wounding induced phenolics biosynthesis and being polymerised into suberin poly(phenolics) (SPP) in advance of suberin poly(aliphatics) (SPA) accumulation. Specifically, rapid expression of genes (e.g. PAL , C4H , 4CL , POD ) associated with the biosynthesis and polymerisation of phenolics, in consistent with SPP accumulation 3days after wounding, followed by the massive accumulation of SPA and relevant gene expressions (e.g. KCSs , FARs , CYP86A1 /B1 , GPATs , ABCGs , GELPs ). Additionally, wound-induced abscisic acid (ABA) and jasmonic acid (JA) consistently correlated with suberin deposition and relevant gene expressions indicating that they might play a central role in regulating wound suberisation in yam tubers.

Quality and biochemical properties of artificially hibernated crucian carp for waterless preservation.

The aim of this study was to explore the artificial hibernation of crucian carp for waterless preservation and to characterize the quality and biochemical properties during and after the hibernation. Anesthetized crucian carp using eugenol were stored at 8 °C with 90 % oxygen and 95-100 % relative humidity for 38 h and then transferred to fresh water to recover. Liquid loss and cooking loss had no significant changes (p > 0.05). The total volatile basic nitrogen content and 2-thiobarbituric acid value in hibernated fish were significantly higher (p < 0.05) than fresh and recovered groups. Serum cortisol, glutamic-oxaloacetic transaminase (GOT), alkaline phosphatase (AKP), and acid phosphatase (ACP) activities significantly increased (p < 0.05) during hibernation, while glutamic-pyruvic transaminase (GPT) had no significant change (p > 0.05). Both ACP and AKP activities decreased upon the fish recovered, but only the ACP activity returned to normal. However, there were increased serum glucose concentration, GOT and GPT activities in recovered fish. On the basis of these findings, it can be concluded that the artificially hibernated life of crucian carp was 38 h by the combination of anaesthetizing and low temperature. The muscle quality would not be influenced, and most of the stress responses would disappear after hibernated fish recovered.