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Sweet potato (Ipomoea batatas (L.) Lam.) is one of the most widely cultivated crops in the world, with outstanding stress tolerance, but drought stress can lead to a significant decrease in its yield. To reveal the response mechanism of sweet potato to drought stress, an integrated physiological, transcriptome and metabolome investigations were conducted in the leaves of two sweet potato varieties, drought-tolerant zhenghong23 (Z23) and a more sensitive variety, jinong432 (J432). The results for the physiological indexes of drought showed that the peroxidase (POD) and superoxide dismutase (SOD) activities of Z23 were 3.68 and 1.21 times higher than those of J432 under severe drought, while Z23 had a higher antioxidant capacity. Transcriptome and metabolome analysis showed the importance of the amino acid metabolism, respiratory metabolism, and antioxidant systems in drought tolerance. In Z23, amino acids such as asparagine participated in energy production during drought by providing substrates for the citrate cycle (TCA cycle) and glycolysis (EMP). A stronger respiratory metabolism ability could better maintain the energy supply level under drought stress. Drought stress also activated the expression of the genes encoding to antioxidant enzymes and the biosynthesis of flavonoids such as rutin, resulting in improved tolerance to drought. This study provides new insights into the molecular mechanisms of drought tolerance in sweet potato. [ABSTRACT FROM AUTHOR]

Sea cucumber (Apostichopus japonicus) is an excellent model for investigating effects of bottom-dwellers on carbon migration and transformation. However, the molecular mechanism of respiratory metabolism process variation caused by feeding rations is poorly understood. In this study, treatment groups set as 1% (about 0.63 g), 3%, and 7% of total body weight (named F1, F3 and F7 groups respectively). The potential molecular mechanisms behind the functions of respiratory tree and body wall were investigated by RNA-Seq. A total of 52411 expressed genes were identified from 89342 expressed transcripts. The results showed 759, 254 and 334 genes were up-regulated, and 334, 445 and 992 genes were down-regulated in respiratory tree of F1 vs. F3, F1 vs. F7 and F3 vs. F7, respectively. Meanwhile, 2070, 1601 and 896 genes were up-regulated, and 1303, 1337 and 1144 genes were down-regulated in body wall between F1 vs. F3, F1 vs. F7 and F3 vs. F7, respectively. Differentially expressed genes were enriched in salivary secretion and ECM-receptor interaction pathways in respiratory tree, and in various types of N-glycan biosynthesis, ribosome and sphingolipid metabolism pathways in body wall. These results suggested respiratory tree and body wall were involved in activation of respiratory metabolisms in response to different feeding rations. Our research provided valuable knowledge for physiological differences in respiratory metabolism. [ABSTRACT FROM AUTHOR]

Sweet potato (Ipomoea batatas (L.) Lam.) is one of the most widely cultivated crops in the world, with outstanding stress tolerance, but drought stress can lead to a significant decrease in its yield. To reveal the response mechanism of sweet potato to drought stress, an integrated physiological, transcriptome and metabolome investigations were conducted in the leaves of two sweet potato varieties, drought-tolerant zhenghong23 (Z23) and a more sensitive variety, jinong432 (J432). The results for the physiological indexes of drought showed that the peroxidase (POD) and superoxide dismutase (SOD) activities of Z23 were 3.68 and 1.21 times higher than those of J432 under severe drought, while Z23 had a higher antioxidant capacity. Transcriptome and metabolome analysis showed the importance of the amino acid metabolism, respiratory metabolism, and antioxidant systems in drought tolerance. In Z23, amino acids such as asparagine participated in energy production during drought by providing substrates for the citrate cycle (TCA cycle) and glycolysis (EMP). A stronger respiratory metabolism ability could better maintain the energy supply level under drought stress. Drought stress also activated the expression of the genes encoding to antioxidant enzymes and the biosynthesis of flavonoids such as rutin, resulting in improved tolerance to drought. This study provides new insights into the molecular mechanisms of drought tolerance in sweet potato.

Feeding ration is one of the most important factors that directly affect growth and physiology progress of sea cucumber Apostichopus japonicus. In present study, a 32-day experiment was carried out to investigate the effects of feeding ration (1%, 3%, and 7% of total body weight, named F1, F3 and F7, respectively) on growth performance, carbon allocation, energy budget and CO2 fluxes at water-air interface. Results showed the maximum specific growth rate was observed at F3, while F7 showed negative growth. And F3 exhibited the highest enzyme activities associated with respiration in respiratory tree and body wall. Carbon intake, nitrogen intake and energy intake were significantly affected by feeding ration, while energy allocation between F1 and F3 on growth and excretion were no significant difference, suggesting that increased feeding ration slightly increased the digestive burden. Compared to F1, food conversion efficiency and fecal energy of F3 were reduced, while respiration metabolizable energy was increased. Mean CO2 flux at water-air interface of F3 was significantly higher than that of F1 at noon and dusk, and mean CO2 flux of F7 was significantly lowest than other groups at all sample times. Our results revealed that feeding rations influence CO2 fluxes at water-air interface by altering physiological status, carbon content, and energy allocation for respiration metabolizable of sea cucumber. Our study provides a theoretical basis for promoting the development of efficient low-carbon aquaculture technology for sea cucumber and sustainable development of the industry.

Straw mushroom (Volvariella volvacea) is one of most extensively cultivated mushrooms in Asia with a delicious taste and high nutritional value. However, its special physiological features lead to the rapid loss of its overall quality and marketability during 2-day storage. The present study proposed an accessible and low-cost strategy with industrial-scale potency for long-time postharvest and long-distance distribution by designing a temperature and humidity-controlled walk-in equipment and optimizing the working conditions. The optimized conditions for postharvest with the designed equipment were obtained as pre-cooling treatment at 20 ℃, small size of plastic basket, one-layer stack mode, storage temperature of 15 °C and relative humidity of 90%. Under these conditions, the straw mushrooms maximally maintained the overall sensory/physical/chemical postharvest quality including highest firmness, soluble protein and soluble sugar contents. Further results proved that the optimized conditions maintained the quality by retaining free water, down-regulating the respiration rate and activities/transcriptional levels of key enzymes associated with respiratory metabolism, and maintaining the energy balance in fruiting bodies. [Display omitted] • A low-cost walk-in equipment was designed for postharvest of straw mushroom. • An economical and industrially applicable postharvest strategy was finally proposed. • The strategy extends straw mushroom's storage period to 4 days. • Moderately regulating respiration and energy balance are the potential mechanism. [ABSTRACT FROM AUTHOR]

Trochophore and veliger are vulnerable pelagic larvae and susceptible to environmental toxicants, which are extremely crucial for the population renewal. Cu, Zn and Cd pollution are common elements in metal pollution in coastal areas. Though Pacific abalone is the main economic mollusc in China, its larval response to metals remains unclear. To understand this, the effect of Cu, Zn and Cd toxicity on malformation classification and respiratory metabolism of trochophore and veliger are analysed and measured in this paper. The 48 hr EC50 for abalone trochophore was (18.9 ± 1.0) μg/L for Cu, (65.1 ± 0.3) μg/L for Zn and (1,377.8 ± 68.9) μg/L for Cd respectively. The LC50 of veliger was (45.8 ± 0.9) μg/L for Cu, (50.0 ± 0.9) μg/L for Zn and (1,049.3 ± 37.6) μg/L for Cd respectively. Trochophore died with no shell at 128 μg/L Cu, yet remained alive with multiple broken‐shell bodies at 128 μg/L Zn and failed to form well‐developed shells at 20,480 μg/L Cd. All veliger died with complete shells at the mentioned concentrations. A self‐made device was used to study the effect on respiratory metabolism. The respiratory metabolism level was significantly fluctuating under Cu and Zn exposure and declined under Cd. The results indicated a decreasing order of the metal toxicity to trochophore and veliger as follows: Cu > Zn ≫ Cd. Cu and Zn were the main causes of shell abnormality, and Cd was less toxic. Moreover, the affected respiratory has a negative impact on further larval development. [ABSTRACT FROM AUTHOR]

Jujube fruit may rapidly undergo maturity and senescence during storage, seriously affecting its commercialization. The study aimed to evaluate the role of acidic electrolyzed water (AEW) on energy and respiratory metabolism, and senescence in jujube fruit during cold storage. The results indicated that AEW improved ATP content and energy charge via increasing succinate dehydrogenase, cytochrome C oxidase, H+-ATPase, and Ca2+-ATPase activities and delayed jujube fruit senescence. The treatment was found to improve the activities of nicotinamide adenine dinucleotide kinase, 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase, and the content of NADPH, and reduce oxidative stress. Transcriptome analysis suggested that AEW regulated the expression of the genes associated with glycolysis, citrate cycle, pentose phosphate pathway, oxidative phosphorylation, ROS metabolism, transcription factors, phenylpropane biosynthesis, cell wall metabolism, and plant hormone signal transduction. Therefore, we concluded that AEW may delay the senescence of postharvest jujube fruit by regulating expression of the relevant genes and metabolic pathways. • AEW treatment promoted energy charge by activating energy metabolism-related enzymes. • AEW reduced cellular peroxidation by regulating pyridine nucleotide homeostasis. • AEW was involved in the regulation of differentially expressed genes associated with senescence. • AEW delayed senescence and maintained good quality of jujube fruit. [ABSTRACT FROM AUTHOR]

Respiration and energy metabolism are intricately linked to the quality and senescence of fruit after harvest. This investigation was carried out to examine alternations in quality parameters, respiration, and energy metabolism of 'Zaosu' pears subsequent to phenyllactic acid immersion. Results demonstrated that phenyllactic acid treatment led to a reduction in L * , a * , b * values, ΔE, and mass loss. Additionally, it maintained ascorbic acid, reducing sugar, soluble sugar, soluble solids, and chlorophyll contents; delayed the decrease in flesh firmness and titratable acidity of pears. The activities and gene expressions of glucose-6-phosphate dehydrogenase, glucose phosphate isomerase, hexokinase, nicotinamide adenine dinucleotide kinase, cytochrome C oxidase, and succinate dehydrogenasepears in pears were enhanced by phenyllactic acid. Moreover, phenyllactic acid promoted PbPK , PbAOX , PbH + -ATPase , and PbCa 2+ -ATPase expressions, while inhibiting malate dehydrogenase activity and the expressions of PbPFK and PbMDH in pears. Phenyllactic acid also led to a decrease in the levels of nicotinamide adenine dinucleotide hydrogen and nicotinamide adenine dinucleotide, while causing an increase in the levels of nicotinamide adenine dinucleotide phosphate hydrogen and nicotinamide adenine dinucleotide phosphate within the fruit. Collectively, postharvest phenyllactic acid treatment can effectively preserve the storage quality of 'Zaosu' pears by regulating the activity and gene expression of the key enzymes involved in respiration and energy metabolism. [Display omitted] • Phenyllactic acid maintained the storage quality of Zaosu pears. • Phenyllactic acid activated EMP, PPP and AP in pear fruit. • Phenyllactic acid enhanced key genes expressions in TCA cycle and energy metabolism. • Phenyllactic acid regulated pyridine nucleotides content and ensured energy supply. [ABSTRACT FROM AUTHOR]

• Dongbi longan had a lower aril breakdown index and respiration rate than Fuyan longan. • Dongbi longan had lower aril PGI, SDH, CCO, AAO, PPO activities and NAD(H) content. • Dongbi longan had higher aril NADK and G-6-PDH+6-PGDH activities and NADP(H) content. • Lower aril breakdown of Dongbi via reducing EMP, TCA, CCP and raising PPP respiratory. • Higher aril breakdown of Fuyan by raising EMP, TCA, CCP, and reducing PPP respiratory. This study aimed to investigate the difference between 'Fuyan' longan (Dimocarpus longan Lour. cv. Fuyan) fruit and 'Dongbi' longan (Dimocarpus longan Lour. cv. Dongbi) fruit in term of their aril breakdown and respiratory metabolism. As compared to 'Fuyan' longans, the 'Dongbi' longans exhibited lower fruit respiration rate, lower aril breakdown index, higher NADK activity, higher total activities of G-6-PDH and 6-PGDH, higher contents of NADP and NADPH, lower activities of AAO, CCO, PPO, PGI, and SDH, and lower contents of NAD and NADH in aril. These findings suggest that better storability and lower aril breakdown index in 'Dongbi' longans than 'Fuyan' longans might be due to lower activities of respiratory terminal oxidases, and lower respiratory metabolic pathways of EMP-TCA cycle related-enzymes in 'Dongbi' longan aril, which decreased respiratory rate and reduced the consumption of substrates, and subsequently maintained the integrity of the aril of 'Dongbi' longans during storage. [ABSTRACT FROM AUTHOR]

Highlights • A nano packaging with nano-Ag, TiO2, SiO2 and attapulgite was used for F. velutipes. • Nano packaging elevated NADP and NADPH contents and increased NADK and G6PDH activities. • Nano packaging maintained F. velutipes mitochondrial structure and integrity during storage. • Nano packaging inhibited respiration, fermentation and maintained enzyme activities of ETS. • Nano packaging increased ATPase activity and ATP and EC levels. Abstract Energy metabolism is accompanied with postharvest senescence, deterioration and physiological disorder in Flammulina velutipes. In this study, nanocomposite packaging material (Nano-PM) inhibited rapid respiration thus preventing accumulation of reactive oxygen species (ROS). In comparison to the normal packaging material (Normal-PM) and no packaging (No-PM), Nano-PM elevated NADP and NADPH contents by increasing the key enzymes in pentose phosphate pathway (PPP), NADK and G6PDH activities, which was due to ROS removal. Moreover, the package enhanced mitochondrial ATPase activity. Regulation of PPP pathway and elevation of ATPase activity was the main reason for the maintenance of mitochondria membrane and structure integrity. Therefore, Nano-PM maintained sufficient ATP content and energy charge by protecting mitochondria structure and regulating electron transfer of mitochondrial respiratory. Overall, Nano-PM maintained energy metabolism by delaying apoptosis and swelling of mitochondria, thus, it alleviated postharvest senescence of F. velutipes. [ABSTRACT FROM AUTHOR]

Oxygen is considered one of the main factors affecting probiotic bacteria survival due to the induction of oxidative damages caused by the action of reactive oxygen species (ROS). It has been shown that oxidative stress resistance in lactic acid bacteria is strongly dependent on the type of cell metabolism. Shift from fermentative to respiratory metabolism (through the addition of heme and menaquinone and in presence of oxygen) was associated to increase in biomass, long-term survival, and production of antioxidant enzymes. The aim of this work was to investigate the effect of aerobic (presence of oxygen) and respiratory (presence of oxygen, heme, and menaquinone) cultivation on the growth kinetic, catalase production, oxygen uptake, and oxidative stress response of Lactobacillus johnsonii/gasseri strains previously isolated from infant feces. Seven strains showed to consume oxygen under aerobic and respiratory conditions. The strain AL5 showed a catalase activity in both growth conditions, while AL3 showed this activity only in respiratory condition. Respiratory condition improved their tolerance to oxidative compounds (hydrogen peroxide and ROS generators) and further they showed promising probiotic features. The exploration of respiratory competent phenotypes with probiotic features may be extremely useful for the development of competitive starter or probiotic cultures.

Effects of propyl gallate on metabolisms of respiration and energy of harvested ‘Fuyan’ longans and its relationship to pericarp browning were investigated. Compared to control longans, propyl gallate could reduce ascorbic acid oxidase (AAO) activity, lower cytochrome C oxidase (CCO) activity during early-storage and mid-storage, increase NADK activity, elevate contents of NADP and NADPH, decrease contents of NAD and NADH, in addition, lower the decreases of ATP content and energy charge (E.C.), increase activities of mitochondrial H + -ATPase, Ca 2+ -ATPase and Mg 2+ -ATPase during early-storage and mid-storage. Above results suggested that propyl gallate-retarded browning development in pericarp of harvested longans was resulted from decreases in activities of respiratory terminal oxidases like CCO and AAO, increase in proportion of pentose phosphate pathway (PPP) to Embden-Meyerhof pathway (EMP) and tricarboxylic acid (TCA) cycle, and maintenance of mitochondrial integrity via retaining higher levels of ATP content and energy charge, as well as higher activities of mitochondrial ATPase. [ABSTRACT FROM AUTHOR]

Lasiodiplodia theobromae (Pat.) Griff. & Maubl. is a major pathogen causing decay of harvested longan fruit. The roles of energy status regulated by 2,4-dinitrophenol (DNP) and adenosine triphosphate (ATP) in disease development regarding respiratory metabolism of L. theobromae -inoculated “Fuyan” longan fruit were studied. Compared with L. theobromae -inoculated longans, DNP treatment could promote the index of fruit disease, accelerate the decrease in energy charge, increase respiration rate and the activities of respiratory terminal oxidases like CCO, AAO and PPO, elevate contents of NAD and NADH, but decrease NAD kinase activity, as well as contents of NADP and NADPH; however, exogenous ATP supply acted contrarily. Above results suggested the different energy status caused by DNP and ATP treatments accelerated or delayed the disease development of L. theobromae -inoculated longans via regulating Embden-Meyerhof pathway (EMP) and tricarboxylic acid (TCA) cycle, pentose phosphate pathway (PPP) and activities of respiratory terminal oxidases. [ABSTRACT FROM AUTHOR]

The respiration and energy metabolisms of refrigerated peach fruit and their relationship to chilling injury (CI) treated with hydrogen sulfide (H 2 S) were investigated. Results showed that H 2 S treatment reduced the activities of hexokinase (HK), phosphor-glucose isomerase (PGI), phosphofructokinase (PFK) and pyruvate kinase (PK), and the contents of glucose, pyruvate and nicotinamide adenine dinucleotide (hydrogen) (NAD(H)) in the Embden-Meyerhof-Parnas (EMP) and tricarboxylic acid (TCA)-cycle compared to control and hypotaurine (HT, H 2 S scavenger) treatment, resulting in a lower respiration rate. Meanwhile, H 2 S treatment increased the activities of NADK, glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) and NADP(H) contents in the pentose phosphate pathway (PPP), while HT showed the opposite results. Moreover, H 2 S treatment induced the higher activities of adenosine triphosphatases (ATPases), succinic dehydrogenase (SDH) and cytochrome C oxidase (CCO) along with enhanced levels of ATP and energy charge, whereas HT suppressed energy generation, which increased cell membrane permeability and malondialdehyde content. Therefore, results suggested that H 2 S could maintain the integrity of the membrane structure by inhibiting the respiration and substance consumption in EMP pathway, increasing the proportion of PPP and energy supply to alleviate CI in peaches. • Respiration and energy metabolisms might be involved in CI development in peaches. • H 2 S inhibited the EMP pathway by suppressing related enzymes activities. • H 2 S increased PPP by enhancing related enzyme activities and higher NADP(H) level. • H 2 S improved energy charge by activating energy metabolism-related enzymes. [ABSTRACT FROM AUTHOR]

Black pepper extracts reportedly inhibit food spoilage and food pathogenic bacteria. This study explored the antimicrobial activity of black pepper chloroform extract (BPCE) against Escherichia coli and Staphylococcus aureus. The antibacterial mechanism of BPCE was elucidated by analyzing the cell morphology, respiratory metabolism, pyruvic acid content, and ATP levels of the target bacteria. Scanning electron micrographs showed that the bacterial cells were destroyed and that plasmolysis was induced. BPCE inhibited the tricarboxylic acid pathway of the bacteria. The extract significantly increased pyruvic acid concentration in bacterial solutions and reduced ATP level in bacterial cells. BPCE destroyed the permeability of the cell membrane, which consequently caused metabolic dysfunction, inhibited energy synthesis, and triggered cell death. [ABSTRACT FROM AUTHOR]

• The mechanism of CPPU promoting grape fruiting was elucidated from two aspects, energy metabolism and respiratory metabolism. • Establish the relationship between CPPU and energy. • It provides new insights for the study of 'Kyoho' grape berry setting. The energy status, the level of respiration metabolism are improtant index reflecting plant growth state, participates in many growth processes. However, their relationship to berry setting remain unclear. In this study, the grape of 'kyoho' of CPPU [CPPU, N-(2-coloro-4-pyridinyl)-N-phenylurea] treated were used to measurement physiological indicators. The results showed that CPPU treatment reduced respiratory rate, reduced Cytochrome C oxidase (CCO) and ascorbic acid oxidase (AAO) activity, reduced NAD kinase (NADK) activity, maintained low nicotinamide adenine denucleotie phosphate (NADP) and nicotinamide adenine denucleotie phosphate reduced form (NADPH) levels, reduced nicotinamide adenine denucleotie (NADH) levels, and slowed down the reduction of energy charge. These results provided strong evidence that CPPU treatment promoted grape berry setting due to increased energy status, increased Embden-Meyerhof pathway (EMP) and the tricarboxylic acid (TCA) cycle respiratory metabolic pathways, decreased pentose phosphate pathway (PPP), and decreased CCO and AAO activity of respiratory terminal oxidase. [ABSTRACT FROM AUTHOR]

• SA retarded the disease development of harvested longans caused by P. longanae. • SA raised longan disease resistance via regulating energy and respiratory metabolism. • SA maintained a higher level of energy charge in P. longanae- inoculated longans. • SA reduced respiration rate but raised PPP pathway in P. longanae -inoculated longans. • SA raised EMP, TCA cycle and CCP pathways in P. longanae -inoculated longans. This study investigated the effects of salicylic acid (SA) on the disease development, respiration rate, energy status, and respiratory metabolism in Phomopsis longanae Chi-inoculated longans. SA treatment reduced the fruit disease index and respiration rate of P. longanae -inoculated longans as compared to the fruit with mere inoculation. SA treatment suppressed the decline of energy charge, decreased the activities of PGI, SDH and CCO, but boosted the G-6-PDH+6-PGDH and NADK activities. Meanwhile, the NAD and NADH contents were decreased, but NADP and NADPH contents were increased. These findings demonstrated that SA could be used to the inhibit disease development in harvested longans because SA treatment helped maintain a high energy charge level, decreased respiration rate and respiratory pathways like EMP-TCA cycle and CCP, but increased PPP respiratory pathway. This study indicated that the SA treatment was a facile and effective way to retard the disease development of postharvest longans. [ABSTRACT FROM AUTHOR]

Oxygen is considered one of the main factors affecting probiotic bacteria survival due to the induction of oxidative damages caused by the action of reactive oxygen species (ROS). It has been shown that oxidative stress resistance in lactic acid bacteria is strongly dependent on the type of cell metabolism. Shift from fermentative to respiratory metabolism (through the addition of heme and menaquinone and in presence of oxygen) was associated to increase in biomass, long-term survival, and production of antioxidant enzymes. The aim of this work was to investigate the effect of aerobic (presence of oxygen) and respiratory (presence of oxygen, heme, and menaquinone) cultivation on the growth kinetic, catalase production, oxygen uptake, and oxidative stress response of Lactobacillus johnsonii/gasseri strains previously isolated from infant feces. Seven strains showed to consume oxygen under aerobic and respiratory conditions. The strain AL5 showed a catalase activity in both growth conditions, while AL3 showed this activity only in respiratory condition. Respiratory condition improved their tolerance to oxidative compounds (hydrogen peroxide and ROS generators) and further they showed promising probiotic features. The exploration of respiratory competent phenotypes with probiotic features may be extremely useful for the development of competitive starter or probiotic cultures.

Energy status and respiration metabolism of "Fuyan" longan fruit treated by hydrogen peroxide (H2O2) and their relationship to pericarp browning were studied. The results displayed that H2O2 significantly increased the respiration rate, increased activities of respiratory terminal oxidases like cytochrome C oxidase (CCO) and ascorbic acid oxidase (AAO), decreased NAD kinase activity, maintained lower contents of NADP and NADPH as well as higher amounts of NAD and NADH, and accelerated the decrease of energy charge. These results gave convincing evidence that the treatment of H2O2 for accelerating longan pericarp browning was due to an increase of energy deficiency, an increase of respiratory metabolic pathways of Embden-Meyerhof pathway (EMP) and tricarboxylic acid (TCA) cycle, a decrease of pentose phosphate pathway (PPP) of respiratory pathway, and an increase of activities of respiratory terminal oxidases like CCO and AAO.