Cytochrome Content Research Articles

Physiological potential of extracellular polysaccharide in promoting Geobacter biofilm formation and extracellular electron transfer

Geobacter sulfurreducens biofilms have promising applications in renewable energy, pollutant bioremediation, and bioelectronic applications. Genetically manipulating G. sulfurreducens biofilms is an effective strategy to improve the capacity of extracellular electron transfer (EET). Extracellular polysaccharide, a sticky component surrounding microbes, plays an important role in EET. Herein, we constructed a mutant of G. sulfurreducens strain PCA overexpressing the gene GSU1501 (part of the ATP-dependent exporter of the polysaccharide biosynthesis gene operon), designated strain PCA-1501, to increase EET capacity. Experimental results showed that the overexpression of GSU1501 increased extracellular polysaccharide secretion by 25.5%, which promoted the formation of biofilm with higher thickness and viability, as well as the content of extracellular c-type cytochromes. Compared with the control strain, the mutant showed a higher capacity of Fe(III) oxide reduction and current generation (increased by 20.4% and 22.2%, respectively). Interestingly, the overexpression of GSU1501 hindered the pili formation by reducing the transcription level of pilA; a compensatory relationship between extracellular polysaccharide and pili in promoting biofilm formation deserves further investigation. This study provides a feasible method to promote the EET capacity of G. sulfurreducens biofilms, which benefit their bioelectrochemical applications.

Dynamic Collapse Mechanism of Alveolar Type 1 Caveolae Buds Modeled as Cubic Mesophase Lyotropic Liquid Crystal Formation and Growth

The alveolar type 1 (AT1) cells cover 95% of the cell surface area while the alveolar type 2 cells cover the remaining 5% of 100–150 m2 surface area of the lung. AT1 maintain membrane integrity by surface tension via caveolin proteins that stretch and collapse the membrane bilayer in physiological pressure cycling, however, collapse mechanics of the AT1 membrane have not been elucidated. Golani et al. modeled globular caveolin collapse structure base on mean curvature and lateral tension, and other sources have constructed similar models. The parameters are transformations of the critical packing parameter CPP equals monomer dimensions predicts that the monolayer shape of surfactants, described as v/al. Deng et al. model for gemini surfactants at the air‐water interface and Turner et al. model for the formation of caveolae bulbs via energy displacement of a membrane bound proteins have proposed similar geometric theories that show resemblance to lyotropic liquid crystal swell equation. The models feature common mathematical properties which are 1) spherical geometry, 2) lattice parameter‐based expansion, and 3) monomer population as mechanical descriptors of bilayer transformation. Each model correlated positively with cubic formation and decrease in surface tension. Krianeva et al. showed that monolayer of monoolein formed a new phase of bicontinuous phase, P4332, as the concentration of protein Horse cytochrome c increased. The spherical formation models predicted mesophases are cubic meaning that they are CPP >> 1, micellar cubic shape. The overall result, the caveolin bud shape is cubic bicontinuous mesophase, which is stabilized under physiological pressure cycling in the AT1 cell. We propose, the caveolin bud shape is a cubic bicontinuous mesophase stabilized under physiological pressure cycling in AT1 cell membrane and mechanics can be modeled by using the lamellar to cubic transition or the swelling law using change in surface tension vs lattice parameter as the formation rate. Furthermore, caveolin and cavin proteins present during the time of formation induce invagination, and, second, stabilization and fragility. Agarwal et al. show the transition phase between isotropic and cubic mesophase is a volume fraction difference of 0.05, a metastable polyhedral lattice produced by caveolin proteins, characterizing bud formation as plastic liquid crystal phase transition. This model could explain mechanoprotection by caveolae bud, and gives us a platform to think about self‐assembling monomer‐based medicines when approaching physical stretch dysfunction repair in the lung.Equations are models that describe cubic expansion from the lamellar setting across several membrane simulations. Equation 1 (left) describes the radius, r1, of Gemini surfactant. Equation 2 (middle) describes the formation of caveolae bulbs via the energy displacement of membrane‐bound proteins. Equation 3 (left) describes the swelling law of lyotropic mesophases.Figure 1

Calcium-calmodulin-dependent protein kinase type 2 induces apoptosis of hepatocytes after liver transplantation.

The warm ischemia-reperfusion injury confines the prevalence of allografts. To improve the success rate of allotransplantation, we designed experiments to study the mechanism of calcium-calmodulin-dependent protein kinase type 2 (CaMK II) in ischemia-reperfusion (I/R) injury. We established the I/R model in SD rats and performed the liver transplantation (LT). As a result, the expression of CaMK II in tissues was detected. CaMK II was interfered with and overexpressed by the transference of the lentivirus vector, and the hepatocyte apoptosis and viability were inspected. At the same time, the content of cytochrome c and apoptosis-inducing factor (AIF) were determined. The measurement of mitochondrial membrane potential and detection of intercellular calcium levels were performed. The expression of CaMK II significantly increased and is highly corresponded with the duration of warm ischemia. In BRL-3A cells and liver tissues, increased cellular apoptosis and less viability had been observed in the CaMK II overexpression group. Cytochrome c and AIF were also largely increased compared to the interfered group. Moreover, apparent mitochondrial membrane potential loss has also been detected in the CaMK II overexpression group. It suggested that CaMK II induces cell apoptosis. Our findings may give a novel indication that inhibition of CaMK II could be a new way for the therapy of warm ischemia-reperfusion injury after LT in future clinical practice.

Varying the pH and Liposome Content of Cytochrome C - Liposome Mixtures

Varying the pH and Liposome Content of Cytochrome C - Liposome Mixtures

Artemisinin and its derivatives target mitochondrial c-type cytochromes in yeast and human cells

Artemisinin and its derivatives kill malaria parasites and inhibit the proliferation of cancer cells. In both processes, heme was shown to play a key role in artemisinin bioactivation. We found that artemisinin and clinical artemisinin derivatives are able to compensate for a mutation in the yeast Bcs1 protein, a key chaperon involved in biogenesis of the mitochondrial respiratory complex III. The equivalent Bcs1 variant causes an encephalopathy in human by affecting complex III assembly. We show that artemisinin derivatives decrease the content of mitochondrial cytochromes and disturb the maturation of the complex III cytochrome c1. This last effect is likely responsible for the compensation by decreasing the detrimental over-accumulation of the inactive pre-complex III observed in the bcs1 mutant. We further show that a fluorescent dihydroartemisinin probe rapidly accumulates in the mitochondrial network and targets cytochromes c and c1 in yeast, human cells and isolated mitochondria. In vitro this probe interacts with purified cytochrome c only under reducing conditions and we detect cytochrome c-dihydroartemisinin covalent adducts by mass spectrometry analyses. We propose that reduced mitochondrial c-type cytochromes act as both targets and mediators of artemisinin bioactivation in yeast and human cells.

Effect of anolytic nitrite concentration on electricity generation and electron transfer in a dual-chamber microbial fuel cell.

This study reports the effect of anolytic nitrite concentration on electricity generation and electron transfer in microbial fuel cells (MFCs). Anolytic nitrite enhanced the electricity generation capability of the MFCs at relatively low concentrations (< 60mg·L-1) but inhibited the activity of anodic electrogenic bacteria at high concentrations. In the anode chamber of the MFC, nitrite was converted to nitrate-releasing electrons before being quickly removed through denitrification. Nitrite alone (in the absence of organic matters) could not perform as an electricity production matrix but promoted electricity production as a co-matrix in the MFC. At an influent nitrite concentration of 60mg·L-1, the coulombic efficiency of the MFC was minimized at approximately 5.4%, and the charge transfer resistance was also lowest, while the concentrations of extracellular polymeric substances (EPS) and cytochrome c were both maximized. Higher anolytic nitrite concentrations (> 60mg·L-1) inhibited the production of cytochrome c and EPS and increased the charge transfer resistance, thereby reducing the efficiency of electron transfer in the anodic biofilm. The results provide valuable guidelines for MFC applications in wastewater treatment processes with nitrite-containing influents.

Phytochemical, Antioxidant and Mitochondrial Permeability Transition Studies on Fruit-Skin Ethanol Extract ofAnnona muricata

Uncontrolled cell proliferation hallmarks cancer and most cancer cells have developed multiple resistance to the drugs employed for their treatment. The study examined the phytochemical and antioxidant properties of the fruit-skin ethanol extract of Annona muricata Linn. (ESA) and its effect on rat liver mitochondrial membrane permeability transition (MMPT). Qualitative phytochemical study and antioxidant assays were carried out following established protocols while the opening of the MMPT pore in the presence of varying concentrations of the extract was assayed spectrophotometrically under succinate-energized conditions. Calcium chloride (CaCl2) and spermine were used to trigger and inhibit pore opening respectively. Cytochrome c release was assayed for using ELISA kit. Terpenoids, steroids, phenols among other phytochemicals were found present in ESA and the extract showed very low antioxidant properties at the tested concentrations based on the diphenyl-1-picryhydrazyl (DPPH) radical scavenging activity assay. Lipid peroxidation was induced in a concentration-dependent manner on both the cytosolic and mitochondrial hepatocyte fractions in vitro. In the absence of CaCl2 0.84 mg/mL concentration of ESA induced MMPT pore opening by 129% while the extracts showed no inhibitory activity in its presence. The induction fold corresponded with the concentrations of cytochrome c released. The fruit-skin ethanol extract of Annona muricata at certain concentrations may possibly contain bioactive compounds that induce apoptosis.

Insights into mechanisms of pranoprofen-induced apoptosis and necroptosis in human corneal stromal cells

Pranoprofen (PPF) is a wildly used anti-inflammatory ophthalmic drug. It was reported that PPF could decrease early epithelialization of scrape wounds in rabbit cornea and could reduce cell activities of cultured human corneal endothelial cells. However, effects of PPF on corneal stromal cells playing important roles in corneal wound healing remain unknown. In this study,in vitro model of cultured human corneal stomal (HCS) cells and in vivo model of rabbit corneas were used to investigate the effects and underlying mechanisms of PPF. Our findings showed that high concentrations of PPF treatment (0.1 % to 0.0125 %) caused limited chromatin condensation and quickly decreased cell viability that was proved to initiate necroptosis in HCS cells through activating receptor interacting protein kinase (RIPK) and mixed lineage kinase domain-like (MLKL). While low concentrations of PPF treatment (0.00625 %) induced DNA fragmentation, apoptotic body formation, ROS generation, activation of caspases and increase in cytoplasmic content of Bad, Bax and cytoplasmic cytochrome c that suggested apoptosis happened through ROS-mediated caspase-dependent and caspase-independent pathways. Studies of rabbit corneas treated with 0.1 % PPF (the clinical concentration) showed that PPF could induce apoptosis of rabbit corneal stromal cells. This work would be helpful for better understanding cytotoxic effects PPF on human corneal cells.

Spermidine improves antioxidant activity and energy metabolism in mung bean sprouts

The effects of exogenous spermidine and dicyclohexylamine (DCHA, spermidine synthesis inhibitor) on the antioxidative system and energy status of germinating mung bean were investigated. Results showed that exogenous spermidine increased the content of total phenolic and ascorbic acid and the antioxidative activity, but reduced activities and gene expressions of peroxidase (POD) and catalase (CAT). These changes might be explained by increased H2O2 content and activities of succinic dehydrogenase (SDH), adenosine triphosphatases (ATPases), and cytochrome c oxidase (CCO), resulting in higher adenosine triphosphate (ATP) and energy charge (EC). Interestingly, spermidine down-regulated expressions of SDH, H+-ATPase, Ca2+-ATPase and CCO whilst DCHA reduced energy metabolism and induced the opposite effects to spermidine, except for ascorbic acid content. Inhibition was reversed by exogenous spermidine. In conclusion, spermidine induced the accumulation of H2O2, enhanced the antioxidative system and improved the energy metabolism to enhance the functional quality of mung bean sprouts.

Deregulating mitochondrial metabolite and ion transport has beneficial effects in yeast and human cellular models for NARP syndrome.

The m.8993T>G mutation of the mitochondrial MT-ATP6 gene has been associated with numerous cases of neuropathy, ataxia and retinitis pigmentosa and maternally inherited Leigh syndrome, which are diseases known to result from abnormalities affecting mitochondrial energy transduction. We previously reported that an equivalent point mutation severely compromised proton transport through the ATP synthase membrane domain (FO) in Saccharomyces cerevisiae and reduced the content of cytochrome c oxidase (Complex IV or COX) by 80%. Herein, we report that overexpression of the mitochondrial oxodicarboxylate carrier (Odc1p) considerably increases Complex IV abundance and tricarboxylic acid-mediated substrate-level phosphorylation of ADP coupled to conversion of α-ketoglutarate into succinate in m.8993T>G yeast. Consistently in m.8993T>G yeast cells, the retrograde signaling pathway was found to be strongly induced in order to preserve α-ketoglutarate production; when Odc1p was overexpressed, this stress pathway returned to an almost basal activity. Similar beneficial effects were induced by a partial uncoupling of the mitochondrial membrane with the proton ionophore, cyanide m-chlorophenyl hydrazone. This chemical considerably improved the glutamine-based, respiration-dependent growth of human cytoplasmic hybrid cells that are homoplasmic for the m.8993T>G mutation. These findings shed light on the interdependence between ATP synthase and Complex IV biogenesis, which could lay the groundwork for the creation of nutritional or metabolic interventions for attenuating the effects of mtDNA mutations.

A nanocarrier based on poly(d,l-lactic-co-glycolic acid) for transporting Na+ and Cl− to induce apoptosis

Transmembrane anion transporters have attracted significant attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis, in which, most of the synthetic anionic transporters are organic small molecules whose synthesis routes are usually complex and tedious, and the related biological research is also only in infancy. Hence, we synthesized a kind of chloride anion (Cl−) and sodium cation (Na+) nanocarrier based on poly(d,l-lactic-co-glycolic acid) (PLGA) which was coated with polydopamine (PDA) to provide target release factor. When the nanocarrier arrives in acidic environment such as lysosomes through endocytosis, Cl− and Na+ will be released fast from the nanocarrier resulting in imbalance of cell homeostasis for inducing apoptosis. Cell experiments show that the nanocarrier promotes apoptosis and leads to an increased concentration of reactive oxygen species. By exploring the concentration of cytochrome c in mitochondria and cytoplasm and the activities of key enzymes caspase-9 and caspase-3 in apoptosis process, it is proved that the apoptotic pathway is caspase-dependent. This novel strategy allows the research of anion transporter no longer limited to artificial synthesis of small molecular and provides a novel and effective direction to investigate ion homeostasis, ion transport and cancer treatment.

Oxygen-containing functional groups on bioelectrode surface enhance expression of c-type cytochromes in biofilm and boost extracellular electron transfer

Introducing oxygen-containing functional groups is a common and convenient method to increase the hydrophilicity of bioelectrodes. In this study, the effect of oxygen-containing functional groups on biofilm was systematically studied to understand how the electron transfer between electrochemically active bacteria (EAB) and bioelectrode was boosted. After electrolysis pretreatment in sulfuric and nitric acid mixture, the oxygen content of the carbon fiber brushes increased from 4.6% to 30.9%. Comparing with the control, the maximum power density increased by 27.7%, while the anode resistance decreased by 21.8%, because charge transfer resistance significantly reduced. The analysis results showed that the content of c-type cytochromes (c-Cyts) in the EAB biofilm was four times higher than that in the control, while the biomass just slightly increased and the bacteria community was similar with that of the control. These findings suggested that the fundamental reason for the enhanced extracellular electron transfer between EAB and electrode was the increased c-Cyts.

Matrine protects oligodendrocytes by inhibiting their apoptosis and enhancing mitochondrial autophagy

Stressed oligodendrocytes (OLGs) activate microglia to produce an inflammatory response, and the impairment of mitochondria further aggravates OLG damage, which is the earliest pathological change in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system. Matrine (MAT), a tetracyclic quinolizine alkaloid derived from the herb radix sophorae flavescentis, has been shown to effectively ameliorate clinical signs of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. However, the mechanisms underlying the effect of MAT treatment need to be further studied. In the present study, we show that MAT effectively suppressed ongoing EAE, and significantly reduced the expression of caspase-3 and alpha B-crystallin in OLGs, therefore lessen OLG apoptosis, microglial activation and inflammatory factors secretion. MAT treatment also reduced the content of cytochrome c and malondialdehyde, an oxidative stress marker, in the central nervous system. In contrast, the levels of autophagy-related proteins Beclin1, microtubule-associated protein l light chain 3 and glutathione peroxidase was upregulated, hence enhancing mitochondrial autophagy and alleviating the imbalance of the oxidation/antioxidation system caused by mitochondrial damage. Our research indicates that MAT is effective in treating EAE, at least in part, by protecting OLGs through inhibiting their apoptosis and enhancing mitochondrial autophagy.

Acupuncture improved depressive behavior by regulating expression of hippocampal apoptosis-related factors in psychological stress-induced depression rats

To investigate the effect of acupuncture on behavior changes and the expression of reactive oxygen species (ROS), cytochrome C, cysteine-containing aspartate-specific proteases-3 (caspase-3), apoptosis inducing factor (AIF) in the hippocampus of rats exposed to chronic restraint stress (CRS), so as to provide experimental evidence for the prevention and treatment of depression. Thirty two male SD rats were equally randomized into control, model, acupuncture and medication (Fluoxetine) groups according to the random number table. The depression model was established by chronic psychological stress stimulation (fasting, water deprivation, chronic restraint combined with solitary raising for 28 days). Manual acupuncture stimulation (2 circles/s) was applied to "Baihui" (GV20), "Yintang" (GV29) and bilateral "Sanyinjiao" (SP6) for 2 min, followed by retaining the needles for 20 min. Rats in the medication group were treated by gavage of Fluoxetine (0.18 mg/mL, 1 mL/100 g body weight). The treatment was conducted once daily for 28 days. The depression-like behavior was evaluated by using open-field test, sucrose preference test, and body weight. The content of ROS of the right hippocampus tissue was detected by using dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay, and the expression levels of cytochrome C, caspase-3 and AIF proteins of hippocampus were determined by using Western blot. After 28 days' stress procedure, the depression rats in the model group showed a significant decrease in the numbers of crossing and rearing of open-field test, sucrose preference index and the body weight compared to the control group (P<0.01). The content of ROS and expression levels of cytochrome C, caspase-3 and AIF in the hippocampus of the model group were significantly increased relevant to the control group (all P<0.01). After the intervention and compared with the model group, the decreased levels of the numbers of crossing and rearing, body weight and sucrose preference index, and the up-regulated levels of content of ROS and expression of cytochrome C, caspase-3 and AIF proteins were all reversed in both acupuncture and medication groups (P<0.01，P<0.05), displaying an anti-depressant effect. The effect of acupuncture was significantly superior to that of medication in up-regulating the numbers of crossing and rearing (P<0.01, P<0.05), and in down-regulating the expression of caspase-3 (P<0.01). No significant differences were found between the medication and acupuncture groups in increasing the body weight and sucrose preference index, and in down-regulating the expression of cytochrome C and AIF proteins (P>0.05). Acupuncture intervention can significantly reduce ROS content and expression level of cytochrome C, caspase-3 and AIF proteins in the hippocampus possibly by inhibiting the chronic psychological stress-hippocampal oxidative stress-mitochondrial apoptotic pathway in psychological stress-induced depression rats, which may contribute to its effect in relieving depression.

BIOMARKERS OF APOPTOSIS IN GLYCOGEN STORAGE DISEASE IN CHILDREN

Glycogen storage disease (GSD) is a rare form of the pathology in children caused by genetically determined pathological changes of the formation or cleavage of glycogen. Depending on the disorders of functions of enzymes involved in glycogen metabolism, there are known up to 15 GSD types, among them there are isolated liver, muscular and mixed forms. There are presented data of the immunoassay analysis of changes in concentrations of the array of proteins considered as biomarkers of apoptosis: sAPO-1/FAS receptor, sFAS-L, cytochrome C, annexin V, caspase-8, caspase-9 and TNF-α in the serum of GSD with the prevailed liver damage (I, III, VI and IX types). There was established the excess of the concentration of cytochrome C in the serum of GSD children by 2,7 times sAPO-1/FAS receptor - 8,9 times, sFAS-L - 2,5 times, annexin V - 4,8 times and TNF-α - 2,9 times in comparison with reference values. Whereby the excess in the cytochrome C content, sAPO-1/FAS receptor, sFAS-L annexin V and the serum was observed in all patients, that indicating to the higher activity of apoptosis in GSD. In this connection GSD in children can be considered as a form of pathology associated with the pronounced apoptosis that contributes to the progression of structural changes in the liver.

Potential of direct interspecies electron transfer in synergetic enhancement of methanogenesis and sulfate removal in an up-flow anaerobic sludge blanket reactor with magnetite

Anaerobic digestion (AD) has been widely applied in the treatment of industrial wastewater containing oxidized sulfur compounds. However, the production of hydrogen sulfide usually limits the syntrophic metabolism proceeded by interspecies hydrogen transfer (IHT), due to its corrosive and toxic properties. The current study was in an attempt to establish direct interspecies electron transfer (DIET) to resist the toxic inhibition from hydrogen sulfide and keep syntrophic metabolism stable. The results showed that, in the presence of magnetite, the methane production was improved about 3–10 folds at each ratio of COD/SO42−, while the enhancement of methanogenesis had almost no negative effect on sulfate reduction. With magnetite, the sludge conductance increased about 3 folds, but the concentration of c-type cytochromes decreased, suggesting that the potential DIET via both electrically conductive pili and outer surface c-type cytochromes was established. Microbial community revealed that, Veillonella species, the Fe(III)-reducing genus capable of reducing sulfate to hydrogen sulfide, were specially enriched with magnetite. Together with the relatively higher abundance of Methanothrix and Methanosarcina species, the novel DIET between Fe(III)/sulfate-reducing genus and methanogens was inferred to be responsible for the synergetic enhancement of methanogenesis and sulfate removal.

Effect of essential lipophilic nutrients on free radical processes in liver mitochondrial fraction of the tumor-bearing rats

Oxidative stress is a universal mechanism of cellular damage of hepatocytes, leading to a decrease in the detoxification function of the liver, which is especially important during oncogenesis. An early correction of these mechanisms by lipophilic essential nutrients could increase the effectiveness of antitumor treatment and prevent the development and progress of cancer. Aim to study the effect of separate and combined use of ω-3 PUFA and vitamin D3 on the intensity of free radical processes, mitochondrial swelling and cytochrome c content in the liver mitochondrial fraction of the tumor-bearing rats during the intensive growth of the tumor has been studied. Material and methods. Studies were carried out on white outbred female rats weighing 130-150 g, which were divided into 5 groups (each n=12). Guerin's carcinoma was used as a model of malignant neoplasm. Carcinoma transplantation was carried out by subcutaneous injection of 0.5 ml of a 30% suspension of cancer cells into saline in the upper thigh region of the right limb. ω-3 PUFAs (120 mg/kg of body weight, per os) and vitamin D3 (600 IU/kg of body weight, per os) were pre-administered for 28 days before the transplantation of Guerin's carcinoma and after transplantation for the entire period of tumor growth in the body (14 days). Liver mitochondrial fraction was isolated by differential centrifugation. The intensity of lipid peroxidation was judged by using spectrophotometry by the content of primary, secondary, and tertiary products in isopropanol extracts. The rate of formation of the superoxide radical was recorded in a test with nitro-blue tetrazolium, the swelling of mitochondria was assessed by a decrease in the optical density of isolated mitochondria, the content of cytochrome c in the mitochondrial and cytosolic fractions was determined by multi-wavelength visible light spectroscopy. Results and discussion. An increase in the content of primary (diene and triene conjugates), secondary (ketodienes; conjugated trienes; TBA-active products) and terminal (Schiff bases) lipid peroxidation products with a simultaneous increase in the generation of superoxide anion-radical was found in the liver mitochondrial fraction of the tumorbearing rats. With the administration of ω-3 PUFA and vitamin D3, both separately and especially when used together, a decrease in the intensity of free radical processes in liver mitochondrial fraction of tumor-bearing rats has been observed. At the same time, mitochondrial swelling decreased, this prevented the release of cytochrome c from mitochondria into cytosol. Conclusion. The administration of the complex ω-3 PUFA and vitamin D3 reduces the processes of lipid peroxidation in the mitochondrial fraction of the liver of tumor-bearing rats while simultaneously restoring the functional ability of mitochondria.

Regulation by nitric oxide on mitochondrial permeability transition of peaches during storage

Mitochondrial membrane permeability transition pores (MPTP) play important roles in mitochondrial function. There are many chemicals in the mitochondria that can act as signal molecules to affect the membrane permeability of mitochondria and mediate to release various enzymes. As a signaling molecule, nitric oxide (NO) is a key player in fruit growth and development. However, the specific mechanism through NO regulates MPTP, and how exogenous NO prolongs fruit storage time are both unclear. In this study, Feicheng peaches were treated with different concentrations of exogenous NO (5, 15 and 30 μmol L−1) and c-PTIO to determine the changes in mitochondrial membrane potential (MMP), hexokinase II activity, the contents of cytochrome C and Ca2+ in mitochondria, as well as the effects of voltage-dependent anion channels (VDAC) and phosphate carrier (PiC) proteins on MPTP during storage. The results showed that NO could form a 1:1 complex either with VDAC or PiC, which proved that NO could react with the protein of PiC or VDAC. Treatment with 15 μmol L−1 NO maintained stable mitochondrial Ca2+ content, and high potential and permeability of the mitochondrial membrane, while decreased cytochrome C content and increased hexokinase activity. When NO was removed, the opposite result appeared. These results indicated that exogenous NO could stabilize MMP and participate in MPTP regulation of peaches during storage.

Inclusion of sprints in moderate intensity continuous training leads to muscle oxidative adaptations in trained individuals.

This study examined adaptations in muscle oxidative capacity and exercise performance induced by two work‐ and duration‐matched exercise protocols eliciting different muscle metabolic perturbations in trained individuals. Thirteen male subjects (V˙O2‐max 53.5 ± 7.0 mL·kg−1·min−1) (means ± SD) performed 8 weeks (three sessions/week) of training consisting of 60 min of moderate intensity continuous cycling (157 ± 20 W) either without (C) or with (C+S) inclusion of 30‐s sprints (473 ± 79 W) every 10 min. Total work performed during training was matched between groups. Muscle biopsies and arm venous blood were collected before as well as immediately and 2 h after exercise during the first and last training session. Plasma epinephrine and lactate concentrations after the first and last training session were 2–3‐fold higher in C+S than in C. After the first and last training session, muscle phosphocreatine and pH were lower (12–25 mmol·kg d.w.−1 and 0.2–0.4 units, respectively) and muscle lactate higher (48‐64 mmol·kg d.w.−1) in C+S than in C, whereas exercise‐induced changes in muscle PGC‐1α mRNA levels were similar within‐ and between‐groups. Muscle content of cytochrome c oxidase IV and citrate synthase (CS) increased more in C+S than in C, and content of CS in type II muscle fibers increased in C+S only (9–17%), with no difference between groups. Performance during a 45‐min time‐trial improved by 4 ± 3 and 9 ± 3% in C+S and C, respectively, whereas peak power output at exhaustion during an incremental test increased by 3 ± 3% in C+S only, with no difference between groups. In conclusion, addition of sprints in moderate intensity continuous exercise causes muscle oxidative adaptations in trained male individuals which appear to be independent of the exercise‐induced PGC‐1α mRNA response. Interestingly, time‐trial performance improved similarly between groups, suggesting that changes in content of mitochondrial proteins are of less importance for endurance performance in trained males.

The Influence of Light Intensity and Leaf Movement on Photosynthesis Characteristics and Carbon Balance of Soybean.

In intercropping systems shading conditions significantly impair the seed yield and quality of soybean, and rarely someone investigated the minimum amount of light requirement for soybean growth and development. Therefore, it is an urgent need to determine the threshold light intensity to ensure sustainable soybean production under these systems. An integrated approach combining morphology, physiology, biochemistry and genetic analysis was undertaken to study the light intensity effects on soybean growth and development. A pot experiment was set up in a growth chamber under increasing light intensity treatments of 100 (L100), 200 (L200), 300 (L300), 400 (L400), and 500 (L500) μmol m−2 s−1. Compared with L100, plant height, hypocotyl length, and abaxial leaf petiole angle were decreased, biomass, root:shoot ratio, and stem diameter were increased, extremum was almost observed in L400 and L500. Leaf petiole movement and leaf hyponasty in each treatment has presented a tendency to decrease the leaf angle from L500 to L100. In addition, the cytochrome content (Chl a, Chl b, Car), net photosynthetic rate, chlorophyll fluorescence values of Fv/Fm, /, ETR, ΦPSII, and qP were increased as the light intensity increased, and higher values were noted under L400. Leaf microstructure and chloroplast ultrastructure positively improved with increasing light intensity, and leaf-thickness, palisade, and spongy tissues-thickness were increased by 105, 90, and 370%, under L500 than L100. Moreover, the cross-sectional area of chloroplast (C) outer membrane and starch grains (S), and sectional area ratio (S:C) was highest under L400 and L500, respectively. Compared to L100, the content of starch granules increased by 35.5, 122.0, 157.6, and 145.5%, respectively in L400. The same trends were observed in the enzyme activity of sucrose-synthase, sucrose phosphate synthase, starch synthase, rubisco, phosphoenol pyruvate carboxykinase, and phosphoenol pyruvate phosphatase. Furthermore, sucrose synthesis-related genes were also up-regulated by increasing light intensity, and the highest seed yield and yield related parameters were recorded in the L400. Overall, these results suggested that 400 and 500 μmol m−2 s−1 is the optimum light intensity which positively changed the leaf orientation and adjusts leaf angle to perpendicular to coming light, consequently, soybean plants grow well under prevailing conditions.