High Energy Status Research Articles

Seasonal and genetic effects on lipid profiles of juvenile Atlantic salmon

Seasonality can influence many physiological traits requiring optimal energetic capacity for life-history stage transitions. In Atlantic salmon, high-energy status is essential for the initiation of maturation. Earlier studies have linked a genomic region encoding vgll3 to maturation age, potentially mediated via body condition. Vgll3 has also been shown to act as an inhibitor of adipogenesis in mice. Here we investigate the influence of season and vgll3 genotypes associating with early (EE) and late (LL) maturation on lipid profiles in the muscle and liver of juvenile Atlantic salmon. We reared Atlantic salmon for two years from fertilization and sampled muscle and liver during the spring and autumn of the second year (at which time some males were sexually mature). We found no seasonal or genotype effect in the muscle lipid profiles of immature males or females. However, in the liver we detected a triacylglycerol enrichment and a genotype specific direction of change in membrane lipids, phosphatidylcholine and phosphatidylethanolamine, from spring to autumn. Specifically, from spring to autumn membrane lipid concentrations increased in vgll3*EE individuals but decreased in vgll3*LL individuals. This could be explained by 1) a seasonally more stable capacity of endoplasmic reticulum (ER) functions in vgll3*EE individuals compared to vgll3*LL individuals or 2) vgll3*LL individuals storing larger lipid droplets from spring to autumn in the liver compared to vgll3*EE individuals at the expense of ER capacity. This genotype specific seasonal direction of change in membrane lipid concentrations provides more indirect evidence of a potential mechanism linking vgll3 with lipid metabolism and storage.

Gene co-expression patterns in Atlantic salmon adipose tissue provide a molecular link among seasonal changes, energy balance and age at maturity.

Sexual maturation in many fishes requires a major physiological change that involves a rapid transition between energy storage and usage. In Atlantic salmon, this transition for the initiation of maturation is tightly controlled by seasonality and requires a high-energy status. Lipid metabolism is at the heart of this transition since lipids are the main energy storing molecules. The balance between lipogenesis (lipid accumulation) and lipolysis (lipid use) determines energy status transitions. A genomic region containing a transcription co-factor of the Hippo pathway, vgll3, is the main determinant of maturation timing in Atlantic salmon. Interestingly, vgll3 acts as an inhibitor of adipogenesis in mice and its genotypes are potentially associated with seasonal heterochrony in lipid storage and usage in juvenile Atlantic salmon. Here, we explored changes in expression of more than 300 genes directly involved in the processes of adipogenesis, lipogenesis and lipolysis, as well as the Hippo pathway in the adipose tissue of immature and mature Atlantic salmon with distinct vgll3 genotypes. We found molecular evidence consistent with a scenario in which immature males with different vgll3 genotypes exhibit contrasting seasonal dynamics in their lipid profiles. We also identified components of the Hippo signalling pathway as potential major drivers of vgll3 genotype-specific differences in adipose tissue gene expression. This study demonstrates the importance of adipose gene expression patterns for directly linking environmental changes with energy balance and age at maturity through genetic factors bridging lipid metabolism, seasonality and sexual maturation.

1-methylcyclopropylene or methyl jasmonate-induced chilling tolerance in a stony hard peach cultivar

Chilling injury (CI) is a severe problem for peach fruit during cold storage. Application of 1-methylcyclopropylene (1-MCP) or methyl jasmonate (MeJA),can alleviate CI in melting flesh peach fruit. However, no information was available about 1-MCP or MeJA on chilling tolerance in stony hard peach fruit and their regulatory mechanisms. In this study, the effects of 10 μmol L−1 1-MCP or 10 μmol L−1 MeJA treatment on CI development, sucrose metabolism, and energy metabolism in stony hard peach fruit cv. ‘Yingshuanghong’ (YSH) were investigated during cold storage. The results showed that 10 μmol L−1 1-MCP or MeJA significantly inhibited the CI index, while MeJA was more effective. Also, both 1-MCP and MeJA treatments had a noticeable impact on energy and sucrose metabolisms. However, 1-MCP treatment was more effective in maintaining a stable and high energy status during cold storage, which might be contributed to alleviating CI. In contrast, MeJA treatment was more effective in regulating sucrose metabolism via activating sucrose synthesis and suppressing sucrose degradation at both the enzymatic and the transcript levels, which might play a crucial role in MeJA-induced cold tolerance. In general, ‘the 1-MCP or MeJA-induced chilling tolerance in stony hard peach fruit cv. ‘YSH’ was attributed to the activation of sucrose and mitochondrial energy metabolisms.

Effects of light irradiation on the textural properties and energy metabolism of postharvest shiitake mushrooms ( Lentinula edodes )

Shiitake mushrooms (Lentinula edodes) easily get deteriorated along with softening during the storage. And energy dissipation is associated with senescence and deterioration of many agro-products. In this study, the evident effect of light irradiation on the softening and the energy dissipation mechanism of shiitake mushrooms (L. edodes) during storage was investigated. Postharvest shiitake mushrooms were treated with light irradiation of 2,300–2,800 lux, and stored at 10°C and 90% RH for 18 days. Textural properties, reactive oxygen species (ROS) level, antioxidant activity, antioxidase activity, malondialdehyde (MDA) content, electrolyte leakage, energy status, enzyme activities, total phenolic content, and genes expressions related to energy metabolism were determined. Results indicated that compared with non-irradiation, qualities of shiitake mushrooms treated with light irradiation were better maintained until 18 days of storage. Light irradiation exerted better effects on maintaining the textural properties of shiitake mushrooms, led to the lower ROS level and cell membrane peroxidation. Moreover, a higher energy status was detected with light irradiation, which could be attributed to the enhanced enzyme activities (H+-ATPase, Ca2+-ATPase, SDH, and CCO activities) and relative gene expressions. Novelty impact statement Light irradiation in the range of 2,300–2,800 lux applied on fresh shiitake mushrooms during the storage, exerted effect on texture properties maintenance, led to the low levels of MDA content, electrolyte leakage, and antioxidant activities. Meanwhile, higher energy status and enhanced enzyme activities as well as relative gene expressions were detected in light-irradiated mushrooms. This study provides a potential application of light irradiation in maintaining the shelf life and storage quality of postharvest shiitake mushrooms, as well as a perspective on correlation between textual quality and energy metabolism.

Yarrowia lipolytica reduces the disease incidence of asparagus infected by Fusarium proliferatum by affecting respiratory metabolism and energy status

This study investigated the effects of Yarrowia lipolytica on disease development, respiratory metabolism, energy status, and reduction state in postharvest asparagus. The result of the study showed that postharvest treatment with Y. lipolytica reduced the disease incidence of asparagus inoculated with Fusarium. proliferatum compared to the untreated ones. Treatment with Y. lipolytica also increased the activities of respiratory-related enzymes phosphofructokinase (PFK), pyruvate kinase (PK), citrate synthase (CS), isocitrate dehydrogenase of mitochondrion (ICDHm), α-ketoglutaricdehydrogenase (α-KGDH), succinodehydrogenase (SDH), 6-phosphate-dehydrogenase (G-6-PDH), 6-phosphogluconate dehydrogenase (6-PGDH), NAD kinase (NADK), and cytochrome oxidase (CCO). Besides, the contents of ATP and energy charges were increased. The activities of H+-ATPase, Ca2+-ATPase, and Mg2+-ATPase were increased after the treatment. Besides, the contents of NAD+ and NADP+ were decreased, but the contents of NADH and NADPH were increased. These findings demonstrated that postharvest treatment of asparagus with Y. lipolytica could be used to inhibit the disease development; because Y. lipolytica increased the respiration rate, helped maintain a high energy status, and a high reduction state. Those results indicated that the Y. lipolytica treatment was a facile and effective way to inhibit the disease development of postharvest asparagus.

Exogenous melatonin maintains leaf quality of postharvest Chinese flowering cabbage by modulating respiratory metabolism and energy status

The efficacy of melatonin on postharvest quality of Chinese flowering cabbage was investigated in this study. Treatment of Chinese cabbage with melatonin significantly delayed leaf yellowing and maintained higher contents of nutrients such as soluble sugars, protein, vitamin C, total flavonoids and phenols during a 7-day storage. Also, melatonin enhanced the activities and expression level of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6-PGDH). Melatonin treatment decreased tissue weight loss, respiration rate, activities of phosphohexose isomerase (PHI), succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), and ascorbic acid oxidase (AAO) and the expression of their corresponding genes. Additionally, melatonin-treated leaves maintained high energy status, as evidenced by higher total ATPase and nicotinamide adenine dinucleotide kinase (NADK) activities, higher energy charge level, adenosine triphosphate (ATP) and adenosine diphosphate (ADP) contents, lower level of adenosine monophosphate (AMP) and transcript abundance of respiratory enzymes. These findings collectively suggest that melatonin maintains leaf quality of postharvest Chinese flowering cabbage might be, at least in part, due to the reduced ratio of Embden-Meyerhof-Parnas pathway (EMP), tricarboxylic acid (TCA) cycle, and cytochrome pathway (CCP), a relatively higher level of pentose phosphate pathway (PPP) and energy status.

Inhibition of downy blight and enhancement of resistance in litchi fruit by postharvest application of melatonin

Litchis are tasty fruit with economic importance. However, the extreme susceptibility of harvested litchis to litchi downy blight caused by Peronophythora litchii leads to compromised quality. This study aimed to study the effects of melatonin on postharvest resistance to P. litchii in ‘Feizixiao’ litchis. Results showed that melatonin restricted lesion expansion in litchis after P. litchi inoculation. Melatonin enhanced the activities of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase and 4-hydroxycinnamate CoA ligase while promoting the accumulations of phenolics and flavonoids. Nicotinamide adenine dinucleotide phosphate content and glucose-6-phosphate dehydrogenase and 6-phosphogluconic acid dehydrogenase activities were higher in treated fruit than control fruit. Higher energy status along with elevated H+-ATPase, Ca2+-ATPase, succinate dehydrogenase and cytochrome C oxidase activities were observed in treated fruit. Ultrastructural observation showed reduced damage in mitochondria in treated fruit. The results suggest that melatonin induced resistance in litchis by modulating the phenylpropanoid and pentose phosphate pathways as well as energy metabolism..

(Invited) Directions of High Energy Batteries and Status of Battery500 Consortium

The success in the development and commercialization of Li-ion batteries has transformation the modern society. Currently there have been intense efforts to further improve battery performances and reduce the cost with many different materials and battery concepts. Based on careful analysis of commercially available advanced electrode materials and state-of-art cell manufacturing processes, we have identified the most feasible pathways for developing high energy batteries with a specific energy much higher than 300 Wh kg−1 using Li metal anode and high capacity metal oxides or sulfur cathode materials. This talk will highlight our analysis, the strategy, and current understanding of the scientific and technological challenges, and discuss recent progresses and directions based on a high-energy cell level design, fabrication, characterization and testing. This talk will also discuss the fundamental mechanisms for premature cell failure, and present recent results for achieving long cycle life.

Inhibition of glycogenolysis prolongs action potential repriming period and impairs muscle function in rat skeletal muscle.

Muscle glycogen content is associated with muscle function, but the physiological link between the two is poorly understood. This study investigated the effects of inhibiting glycogenolysis, while maintaining high overall energy status, on different aspects of muscle function. We demonstrate here that Na+ ,K+ -ATPase activity depends on glycogenolytically derived ATP regardless of high global ATP, with a decrease in activity leading to reduced force production and accelerated fatigue development. The results support the concept of compartmentalized energy transfer with glycogen metabolism playing a crucial role in intramuscular ATP resynthesis and ion regulation. This study gives specific insights into muscular function and may help towards a better understanding of glycogen storage diseases and muscle fatigue. Skeletal muscle glycogen content is associated with muscle function and fatigability. However, little is known about the physiological link between glycogen content and muscle function. Here we aimed to investigate the importance of glycogenolytically derived ATP per se on muscle force and action potential (AP) repriming period, i.e. the time before a second AP can be produced (indicative of Na+ ,K+ -ATPase activity). Single fibres from rat extensor digitorum longus muscles were isolated and mechanically skinned in order to investigate force production and the AP repriming period while global ATP and PCr concentrations were kept high. The importance of glycogenolytically derived ATP was studied by inhibition of glycogen phosphorylase (1,4-dideoxy-1,4-imino-d-arabinitol (DAB; 2mm) or CP-316,819 (CP; 10µm)) or glycogen removal (amyloglucosidase, 20Uml-1 ). Tetanic force decreased by (mean (SD)) 21(15)% (P<0.001) and 76(28)% (DAB) or 94(6)% (CP, P<0.001) in well-polarized and partially depolarized fibres, respectively. In depolarized fibres, twitch force decreased by 16(10)% and 55(26)% with DAB and CP, respectively, with no effect in well-polarized fibres (84(10)%, P=0.14). There was no effect of glycogen phosphorylase inhibition on repriming period in well-polarized fibres (median (25th, 75th percentile): 5(4,5) vs. 4(4,5)ms, P=0.26), while the repriming period was prolonged from 6(5,7) to 8(7,10)ms (P=0.01) in partially depolarized fibres. In line with this, glycogen removal increased repriming period from 5(5,6) to 6(5,7)ms (P=0.003) in depolarized fibres. Together, these data strongly indicate that blocking glycogenolysis attenuates Na+ ,K+ -ATPase activity, which in turn increases the repriming period and reduces force, demonstrating a functional link between glycogenolytically derived ATP and force production.

Effect of ruminal administration of soy sauce oil on rumen fermentation, milk production and blood parameters in dairy cows.

ObjectiveTo evaluate soy sauce oil (a by-product of making whole soybean soy sauce) as a new dietary lipid source, a large amount of soy sauce oil was administered into the rumen of dairy cows.MethodsFour Holstein dairy cows fitted with rumen cannulae were used in a 56-day experiment. Ruminal administration of soy sauce oil (1 kg/d) was carried out for 42 days from day 8 to day 49 to monitor nutritional, physiological and production responses.ResultsDry matter intake and milk yield were not affected by soy sauce oil administration, whereas 4% fat-corrected milk yield and the percentage of milk fat decreased. Although ruminal concentration of total volatile fatty acids (VFA) and the proportion of individual VFA were partially affected by administration of soy sauce oil, values were within normal ranges, showing no apparent inhibition in rumen fermentation. Administration of soy sauce oil decreased the proportions of milk fatty acids with a carbon chain length of less than 18, and increased the proportions of stearic, oleic, vaccenic and conjugated linoleic acids. Conjugated linoleic acid content in milk became 5.9 to 8.8 times higher with soy sauce oil administration. Blood serum concentrations of non-esterified fatty acid, 3-hydroxybutyric acid, total cholesterol, free cholesterol, esterified cholesterol, triglyceride and phospholipid increased with administration of soy sauce oil, suggesting a higher energy status of the experimental cows.ConclusionThe results suggest that soy sauce oil could be a useful supplement to potentially improve milk functionality without adverse effects on ruminal fermentation and animal health. More detailed analysis is necessary to optimize the supplementation level of this new lipid source in feeding trials.

1 Assessing the energy status of porcine embryos by means of biodynamic imaging

Assisted reproductive technologies are powerful tools for enhancing production in livestock or treating infertility in humans. Unfortunately, the success rate of the technologies is rather low. A major reason for the poor efficiency is the lack of methods to reliably assess the developmental potential of the embryos before transfer into recipients. Therefore, a noninvasive method to ensure the selection of only the best embryos for transfer would be highly desirable. Biodynamic imaging is a compelling new microscopy that uses intracellular Doppler spectroscopy to perform label-free, noninvasive optical measurements of cellular fitness. The aim of this study was to investigate whether biodynamic imaging can be used to assess the energy status of the embryos, which may be indicative of their viability. Porcine oocytes matured invitro were parthenogenetically activated by an electrical pulse and cultured for 2 days. The parthenotes were then divided into two groups, and approximately half of them were incubated for an additional 2 days in the presence of 20mM sodium azide. Sodium azide is an inhibitor of oxidative phosphorylation and is known to block ATP production. The rest of the embryos were cultured without sodium azide and used as a control to indicate normal ATP levels. At the end of the culture period embryos that reached the 8- to 16-cell stage were evaluated by our biodynamic imaging system to assess their energy status, after which they were lysed and their ATP contents were determined by means of a bioluminescence assay. A total of 68 embryos (32 treated with the inhibitor and 36 control) were evaluated. The ATP content analysis showed that the control embryos had significantly more ATP than those treated with sodium azide as determined by Student's t-test (5.04±1.07 vs. 1.31±0.57; P&amp;lt;0.05). A correlative study was then completed where biodynamic biomarkers were used to classify embryos to estimate the ability of biodynamic imaging to identify embryos with high or low energy status. A set of 13 biomarkers representing each embryo as a feature vector was used to train a classifier. We found that the cross-validated classifier had a sensitivity and specificity of ~80%. In addition, a receiver-operator curve constructed by varying the ATP threshold of the independent bioluminescence assay had an area-under-the-curve of 0.81. These results indicate that biodynamic imaging is able to determine the energy status of the embryos noninvasively and has great potential in the assessment of embryo viability.

Effect of benzothiadiazole treatment on improving the mitochondrial energy metabolism involved in induced resistance of apple fruit during postharvest storage

The effects of benzothiadiazole (BTH) on Penicillium expansum development, mitochondria energy metabolism, and changes in the number and structure of mitochondria in apple fruit were investigated after the fruit were immersed in 100 mg L−1 BTH for 10 min and then stored at 22 °C. The results indicated that BTH treatment significantly decreased the lesion diameter of fruit challenged with P. expansum; further, treatment enhanced the activities of mitochondrial respiratory metabolism-related enzymes, such as succinate dehydrogenase, cytochrome oxidase, H+-ATPase and Ca2+-ATPase, along with high ATP level and energy status in apple fruit during storage. Moreover, transmission electron microscopy results indicated that BTH treatment was beneficial for maintaining the number and structure of mitochondria during storage. The results suggested that BTH treatment enhanced ATP levels via mitochondrial energy metabolism, which might contribute to the induced resistance in apple fruit during storage.

Cryopreservation and quality assessment of boar semen collected from bulk samples

The purpose of this study was to examine sperm quality after cryopreservation of ejaculates collected as a bulk sample, which is routinely part of semen collection, and to compare this quality with the sperm-rich fraction in boars. Ejaculates were collected as sperm-rich fractions (SRF) and bulk samples (BE) using a gloved-hand technique. Fresh semen quality in terms of semen volume, sperm concentration, total sperm motility and pH were conventionally evaluated. Then, semen was cryopreserved using the liquid nitrogen vapour method. The post-thaw sperm quality was evaluated by assessing sperm motility, live sperm with normal apical ridge and high mitochondrial energy status, lipid peroxidation was evaluated using CASA and fluorescent multiple staining and MDA levels were determined using a spectrophotometer, respectively. In terms of fresh semen quality, sperm motility in fresh semen did not differ significantly between the two groups. The treatment with the greater mean volume (BE; P &amp;lt; 0.05) had a lower mean sperm concentration (P &amp;lt; 0.05); meanwhile, the mean ejaculate pH collected as BE was more basic compared with SRF (P &amp;lt; 0.05). However, there were no significant post-thaw quality changes between sperm-rich fractions and bulk samples of semen. In conclusion, ejaculates can be collected as bulk samples without the need to classify fractions for boar semen cryopreservation.

Fibroin treatment inhibits chilling injury of banana fruit via energy regulation

The effects of fibroin on chilling tolerance of harvested banana fruit via energy regulation were investigated after 4 d of storage at 6 °C. Chilling injury index, respiration rate and electrolyte leakage were also investigated. Application of 1 g L−1 fibroin solution reduced effectively chilling injury symptoms and delayed significantly the decreases in ATP level and energy charge (EC) of banana fruit during storage at 6 °C. Compared with the control group, the transcriptional level of MaATPase1 and MaAAC1 were up-regulated while MaAOX1 and MaUCP1 were down-regulated in fibroin-treated banana fruit after 4 d of storage. Meanwhile, fibroin treatment increased the contents of soluble sugars. The results suggested that fibroin treatment exhibited the potential for alleviating chilling injury symptoms of banana fruit during cold storage by maintaining high energy status.

Mitochondrial Complex I Inhibitor Iacs-010759 Reverses the NOTCH1-Driven Metabolic Reprogramming in T-ALL Via Blockade of Oxidative Phosphorylation: Synergy with Chemotherapy and Glutaminase Inhibition

Adult T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy characterized by limited therapeutic options and a high rate of treatment failure due to chemoresistance. T-ALL is largely driven by activating NOTCH1 mutations, where oncogenic NOTCH1 facilitates glutamine oxidation, induces metabolic stress, and facilitates reliance on oxidative phosphorylation (OXPHOS)1. In other malignancies, the shift toward OXPHOS-dependent high-energy status is associated with acquired chemoresistance.In this study, we found that the novel inhibitor of mitochondrial complex I (OXPHOSi) IACS-0107592 has preclinical activity in NOTCH1-mutated T-ALL; we also characterize the cellular and metabolic responses to OXPHOS inhibition and propose that an OXPHOSi be incorporated into standard-of-care therapy to improve outcomes in patients harboring NOTCH1-mutated T-ALL.Exposure to IACS-010759 (0-370 nM) in vitro drastically reduced T-ALL viability, with EC50 ranging from 0.1-10 nM for cell lines (n=7) and from 13-60 nM for patient-derived xenograft (PDX)-derived and primary T-ALL cells (n=10) (Fig.1). Oral administration of IACS-010759 (7.5 mg/kg/day) significantly reduced leukemia burden and extended overall survival (p<0.0001) in two aggressive NOTCH1-mutated T-ALL PDX models and in a murine NOTCH1-driven T-ALL model (Fig.4). Addition of OXPHOS inhibitor to dexamethasone (X), vincristine (V), asparaginase (L), or a combination (VXL) led to additive/synergistic inhibition of cell proliferation in vitro and to doubling of overall survival in vivo (p<0.0001) (Fig.4). Metabolic characterization confirmed that IACS-010759 caused striking dose-dependent decreases in basal and maximal oxygen consumption rates (OCR) and ATP and NADH production in T-ALL cell lines and primary T-ALL samples (p<0.001; Fig.2). Further, pretreatment with V, X, or L shifted T-ALL cell metabolism toward OXPHOS, increasing significantly the OCR that was effectively inhibited by IACS-010759. Pharmacological inhibition of complex I with IACS-010759, similar to knockout of complex I subunit NDUFS4 using CRISPR-CAS9, induced catastrophic changes in mitochondria, with induction of mitochondrial reactive oxygen species (ROS), DNA damage, and activation of the compensatory mTOR pathway. OXPHOS inhibition altered cellular energy homeostasis through reduction of TCA cycle intermediates; decreased glutathione level (by UPLC-MS/MS; p<0.0001) with ROS induction (Fig.3); and depleted the pool of intracellular nucleotides, affecting DNA and RNA synthesis (Fig.2C). Stable isotope-resolved metabolomics (SIRM) flux analysis showed that IACS-010759 (30 nM at 24 h) significantly decreased the flux of glucose through the TCA cycle and redirected it toward lactate production and increased utilization of glutamine for fueling the TCA cycle, in particular through reductive metabolism, uncovering reliance on glutaminolysis as an additional therapeutic target. Consistent with this was the finding that combined OXPHOSi with glutaminase inhibitor CB-839 caused additive reduction of viability of T-ALL cells lines and primary T-ALL cells in vitro (Fig.2), decreased tumor burden (p<0.02), and increased survival in a T-ALL PDX model (p<0.01). This was supported by IACS-induced reduction of tumor burden in a NOTCH1-mutated GLS fl/fl murine model upon tamoxifen-induced GLS knockout (p<0.01).In summary, our findings indicate that OXPHOSi, alone and particularly in combination with standard chemotherapy and GLS inhibition, constitutes a novel therapeutic modality that targets a unique metabolic vulnerability of NOTCH1-mutated T-ALL cells.

Evaluation of electrofishing adopted by Egyptian fish farmers

Upon the demand of a private fish farmer, this study was applied to assess the influence of electro-fishing adopted by some Egyptian fish farmers on the fish welfare and quality. Therefore, a total of 60 Nile tilapia (Oreochromis niloticus) were sampled; from which 30 were stunned by electrofishing and the remainders by conventional fishing. Biochemical analysis (oxidative stress and energy status), meat quality based on total bacterial count (TBC) and pathological alterations were assessed. Biochemical analysis in both liver and muscle tissue showed that electro-stunned fish exhibited low oxidative stress and high energy status. Meat of electro-stunned fish showed an acceptable limit of TBC (Max. limit 107) while the histopathological examination revealed various tissue reactions. These were in the form of congestion in branchial, hepatoportal, brain and splenic blood vessels with edema in brain and pericardium. In addition, there was mild inflammatory reaction together with the presence of eosinophilic granular cells and perivascular melanophores aggregation in both branchial and muscular tissue.As a consequence of this work, we recommend the use of electrofishing method in Egypt after modifying the current tool by reducing applied voltage. Further studies and more optimization are needed to cover both fish farmers and animal welfare issues, and take in consideration the human safety precautions.

Effect of β-Aminobutyric Acid on Disease Resistance Against Rhizopus Rot in Harvested Peaches.

The effect of β-aminobutyric acid (BABA) on Rhizopus rot produced by Rhizopus stolonifer in harvested peaches and the possible action modes were investigated. Treatment with 50 mmol L−1 of BABA resulted in significantly lower lesion diameter and disease incidence compared with the control. The activities of defense-related enzymes chitinase and β-1,3-glucanase were notably enhanced by this treatment. Meanwhile, BABA treatment also increased lignin accumulation and maintained higher energy status in peaches by enhancing activities of enzymes in the phenylpropanoid and energy metabolism pathways. Semiquantitative reverse transcription PCR results indicated that the transcription of four defense-related genes was substantially and rapidly enhanced only in that BABA-treated fruit upon inoculation with the pathogen. Thus, our results demonstrated that BABA was effective on controlling Rhizopus rot by inducing disease resistance, which includes the increase in gene transcription and activity of defense-related enzymes, the enhancement of cell wall strength, and the maintenance of high energy status in Prunus persica fruit. Moreover, the disease resistance induced by BABA was demonstrated through priming model rather than direct induction.

Proteomic profiling of 24-epibrassinolide-induced chilling tolerance in harvested banana fruit

The mechanism of 24-epibrassinolide (EBR)-induced chilling tolerance in harvested banana fruit was investigated. Results showed that EBR pretreatment remarkably suppressed the development of chilling injury (CI) in harvested banana fruit during 12 days of cold storage at 8 °C, as indicated by lower CI index in treated fruit. Physiological measurements exhibited that EBR treatment reduced the relative electrolyte leakage and malondialdehyde (MDA) content while increased the chlorophyll fluorescence (Fv/Fm), total soluble solids (TSS) and ratio of TSS and titratable acidity. Furthermore, the differentially accumulated proteins of banana fruit in response to EBR and cold treatment were investigated by employing gel-based proteomic in combination with MALDI-TOF-TOF MS and LC-ESI-MS/MS analyses. There were fifty five protein spots to be successfully identified. Notably, most of up-regulated proteins by EBR treatment were related to energy biosynthesis, stress response and cell wall modification. In contrast, proteins involved in protein degradation and energy consumption were down-regulated by EBR treatment. These results suggest that EBR treatment could enhance the defense ability, promote the synthesis and utilization of energy, as well as maintain the protein function via enhancing protein biosynthesis and inhibiting protein degradation, consequently contributing to improvement of cold tolerance in harvested banana fruit. SignificanceTo extend our understanding of chilling injury (CI) of harvested banana fruit, we reported the effect of 24-epibrassinolide (EBR) on CI of banana fruit when stored at 8 °C. It was the first report on the comprehensive proteomic analysis of banana fruit in response to EBR treatment at low temperature. EBR pretreatment significantly reduced CI in harvested banana fruit. Fifty five protein spots were successfully identified. Notably, the most of up-regulated proteins by EBR treatment were related to energy biosynthesis, stress response and cell wall modification. In contrast, proteins involved in protein degradation and energy consumption were down-regulated. These results suggest that exogenous EBR treatment could enhance the defense ability and maintain high energy status. Meanwhile, EBR treatment maintained protein function via enhancing protein biosynthesis and inhibiting protein degradation. These results may help us to understand the molecular mechanism of the chilling tolerance induced by EBR treatment and broaden the current knowledge of the mechanism of CI of harvested banana fruit.

Effect of Potassium Levels on Productivity and Fruit Quality of Tomato (Lycopersicon esculentum L.)

Potassium has significant effect on quantity and quality of tomato yield because of its vital roles in photosynthesis, favoring high energy status and appropriate nutrient translocation and water uptake in plants. However, little is understood or it is being overlooked under Eritrean condition. Besides, poor soil fertility is among the major production constraints in Eritrea. The field experiment was therefore conducted to investigate the effect of potassium levels on productivity and fruit quality of tomato at Hamelmalo, Eritrea. The experiment was conducted in Randomized Complete Block Design with nine potassium levels (0, 50, 100, 150, 200, 250, 300, 350 and 400 kg K2O/ha) replicated thrice. Data was collected on yield and fruit quality parameters and they were subjected to one-way analysis of variance (1-way ANOVA). The results of this study revealed that potassium had significant effect in all yield and quality parameters studied. Fruit diameter, fruit weight per plant, total yield, total soluble solids, specific gravity and fruit dry matter content showed significant increase with an increase in potassium level from 0 to 150 kg K2O/ha and thereafter decreased while fruit moisture content was increased in the range of 150 - 400 kg K2O/ha. As a result, highest fruit weight (1.39 kg/plant), fruit yield (15.45 t/ha), total soluble solids (3.84 oBrix), specific gravity, (1.46) and fruit dry matter (5.68%) were recorded from 150 kg K2O/ha. Therefore it is recommended that potassium fertilizers should be used and balanced NPK fertilizers should be applied to improve yield and quality of tomato produced.

Elevated CO2 improved the growth of a double nitrate reductase defective mutant of Arabidopsis thaliana: The importance of maintaining a high energy status

Impairments in leaf nitrogen (N) assimilation in C3 plants have been identified as processes conditioning photosynthesis under elevated [CO2], especially when N is supplied as nitrate. Leaf N status is usually improved under ammonium nutrition and elevated [CO2]. However, ammonium fertilization is usually accompanied by the appearance of oxidative stress symptoms, which constrains plant development. To understand how the limitations of direct fertilization with ammonium (growth reduction attributed to ammonium toxicity) can be overcome, the effects of elevated [CO2] (800ppm) exposure were studied in the Arabidopsis thaliana double nitrate reductase defective mutant, nia1-1/chl3-5 (which preferentially assimilates ammonium as its nitrogen source). Analysis of the physiology, metabolites and gene expression was carried out in roots and shoot organs. Our study clearly showed that elevated [CO2] improved the inhibited phenotype of the nitrate reductase double mutant. Both the photosynthetic rates and the leaf N content of the NR mutant under elevated CO2 were similar to wild type plants. The growth of the nitrate reductase mutant was linked to its ability to overcome ammonium-associated photoinhibition processes at 800ppm [CO2]. More specifically: (i) the capacity of NR mutants to equilibrate energy availability, as reflected by the electron transport equilibrium reached (photosynthesis, photorespiration and respiration), (ii) as well as by the upregulation of genes involved in stress tolerance were identified as the processes involved in the improved performance of NR mutants.