Mitochondrial dynamics, involving mitochondrial fusion, fission and autophagy, plays an important role in maintaining cellular physiological function and homeostasis. Mitochondria are the "energy plant" of human body, so the changes of mitochondrial fusion, division and autophagy are important for cell respiration and energy production. On the other hand, energy metabolism influences mitochondrial dynamics in turn. This paper reviewed the recent advances in studies on the relationship between energy metabolism and the proteins regulating mitochondrial fusion, fission and autophagy. The association of mitochondrial dynamics with electron chain complex expression, oxidative phosphorylation and ATP synthesis upon exercise intervention will provide theoretical references for the further studies in sports training and disease intervention.
Adenosine Triphosphate ; biosynthesis ; Autophagy ; Energy Metabolism ; Exercise ; Humans ; Mitochondria ; physiology ; Mitochondrial Dynamics ; Mitochondrial Proteins ; metabolism

To explore the effects of ATP concentration in the medium and hypoxia exposure on mitochondrial DNA expression at transcriptional and translational level, rats were exposed to hypoxia in a hypobaric chamber simulating 4000 m above sea level for 3 d (acute hypoxia) or 40 d (chronic hypoxia). Cerebral cortex mitochondria were isolated from control and hypoxia-exposed rats by centrifugation program. The activities of intramitochondrial RNA and protein synthesis were measured respectively by the methods of incorporation of (3)H-UTP or (3)H-Leucine in a cell-free system in vitro in isolated organelle. The effect of different ATP concentrations in medium on incorporation activity of mitochondria from control rat brains was observed. The results showed that there was a 40% reduction in RNA synthesis and a 60% inhibition in protein synthesis in isolated mitochondria in vitro in acute hypoxia exposure compared to control. But in chronic hypoxic exposure, the inhibition of both RNA synthesis and protein synthesis was alleviated, being 72% and 76% of the normoxic control, respectively. Furthermore, the effect of ATP concentration in medium on mitochondrial RNA and protein synthesis in vitro showed two phases. The mitochondrial RNA and protein synthesis were inhibited when ATP concentration was either above or below 1 mmol/L in the incubation medium. These results indicate that hypoxia exposure affects the expression of mtDNA at both transcription and translation levels. It also suggests that the improvement of mitochondrial semi-automation during chronic hypoxic exposure may be at least one of the cellular mechanisms of body adaptation to hypoxia. The regulation of ATP in mitochondrial RNA and protein synthesis is therefore an economic and effective mode of regulation.
Adenosine Triphosphate ; metabolism ; Animals ; Brain ; metabolism ; Hypoxia ; metabolism ; Male ; Mitochondria ; metabolism ; Protein Biosynthesis ; RNA ; biosynthesis ; Rats ; Rats, Wistar

Extracellular ATP (exATP) has been known to be a critical ligand regulating skeletal muscle differentiation and contractibility. ExATP synthesis was greatly increased with the high level of adenylate kinase 1 (AK1) and ATP synthase beta during C2C12 myogenesis. The exATP synthesis was abolished by the knock-down of AK1 but not by that of ATP synthase beta in C2C12 myotubes, suggesting that AK1 is required for exATP synthesis in myotubes. However, membrane-bound AK1beta was not involved in exATP synthesis because its expression level was decreased during myogenesis in spite of its localization in the lipid rafts that contain various kinds of receptors and mediate cell signal transduction, cell migration, and differentiation. Interestingly, cytoplasmic AK1 was secreted from C2C12 myotubes but not from C2C12 myoblasts. Taken together all these data, we can conclude that AK1 secretion is required for the exATP generation in myotubes.
Adenosine Triphosphate/*biosynthesis ; Adenylate Kinase/*metabolism ; Animals ; Cell Line ; Extracellular Space/metabolism ; Isoenzymes/*metabolism ; Mice ; Muscles/cytology/*metabolism

Poor stability existed in the anaphase of the high-cell-density fermentation of Saccharomyces crevisiae for S-adenosyl-L-methionine (SAM) production in 5 L fermentor. To improve the fermentation stability, we studied the addition of diammonium hydrogen phosphate, sodium glutamate and adenosine disodium triphosphate into glucose feeding solution. Study of four fed-batch cultures showed that, after 34 h fermentation, when dry cell weight reached 100 g/L, the addition of 50 g pre-L-methionine and glucose feeding with 10 g/L adenosine disodium triphosphate was optimal for SAM production. Under this condition, after 65.7 h fermentation, both the dry cell weight and the yield of SAM reached the maximum, 180 g/L and 17.1 g/L respectively.
Adenosine Triphosphate ; pharmacology ; Fermentation ; Phosphates ; pharmacology ; S-Adenosylmethionine ; biosynthesis ; genetics ; Saccharomyces cerevisiae ; enzymology ; genetics ; Sodium Glutamate ; pharmacology

To investigate the energy utilization efficiency of Synechococcus sp. PCC7942 under mixotrophic conditions, we studied its growth characteristics in mixotrophic cultures with glucose and acetic acid respectively and discussed the carbon metabolism and energy utilization based on metabolic flux analysis. Results showed that both glucose and acetate could better enhance the growth of Synechococcus sp. PCC7942, and the latter was more effective. The metabolic flux through glycolytic pathway in mixotrophic cultures was stimulated by glucose whereas depressed by acetate, while the flux through the tricarboxylic acid cycle increased in both cases. Under mixotrophic conditions, glucose makes more significant impact on the diminishment of photochemical efficiency of Synechococcus sp. PCC7942. Although the contribution of light energy was smaller, the cell yields based on total energy in mixotrophic cultures were higher comparing with photoautotrophic culture. The energy conversion efficiencies based on ATP synthesis in photoautotrophic culture, mixotrophic cultures with glucose and with acetate were evaluated to be 6.81%, 7.43% and 8.77%, respectively.
Acetic Acid ; pharmacology ; Adenosine Triphosphate ; biosynthesis ; Carbon ; metabolism ; Culture Media ; Culture Techniques ; methods ; Energy Metabolism ; Glucose ; pharmacology ; Synechococcus ; classification ; growth & development ; metabolism

OBJECTIVETo explore the mechanism of reactive oxygen species (ROS) in manganese chloride (MnCl(2))-induced apoptosis in PC12 cells.

METHODSThe model that MnCl(2) induced apoptosis in PC12 cells was established. The apoptotic effect of MnCl(2) on PC12 cells was analyzed with the MTT, the flow cytometry and the DNA fragmentation. The production of ROS and ATP in MnCl(2)-induced apoptosis of PC12 cells was examined. The influence of MnCl(2) on the expression of bcl-xl, bax and the activity of Caspase 3 was also analyzed.

RESULTSMnCl(2) triggered PC12 cells apoptosis in a dose-and time-dependent manner (P < 0.01). The rate of apoptosis was significantly increased (P < 0.01) when MnCl(2) of 2 mmol/L induced PC12 cells for 36 hours. The production of ROS was increased (P < 0.001) and the quantity of ATP was decreased (P < 0.01) in PC12 cells with the same inducement of MnCl(2). The expression of bcl-xl was inhibited and the bax was activated in this process (P < 0.01). Caspase 3 was also activated (P < 0.01).

CONCLUSIONMnCl(2) induces apoptosis of PC12 cells, which is related to the increase of ROS, the inhibition of the mitochondria and the activation of Caspase 3.

Adenosine Triphosphate ; biosynthesis ; Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Chlorides ; toxicity ; DNA Fragmentation ; drug effects ; Manganese Compounds ; PC12 Cells ; Rats ; Reactive Oxygen Species ; metabolism ; bcl-2-Associated X Protein ; biosynthesis ; bcl-X Protein ; biosynthesis

OBJECTIVETo detect the nitric oxide (NO) production and energy metabolism of the interleukin (IL)-1beta-treated residual hepatocytes from rats after partial hepatectomy.

METHODSForty rats were equally divided into partial hepatectomies (PH) group and control group. In the control group the rats were otherwise matched and underwent sham surgeries. The residual hepatocytes were separated by the collagenase perfusion method. The hepatocytes were cultured with cytokines such as IL-1beta. The production of NO in the two groups were measured with Griess reagent method, the production of inducible nitric oxide synthase (iNOS) protein detected with Western blot, the content of the nucleotide in the hepatocytes detected with high-performance liquid chromatography, and the content of the ketone body in the hepatocytes of the two groups determined with the enzymatic method. Afterwards the ketone body ratio (acetoacetate/beta-hydroxy butyrate, KBR) was calculated.

RESULTSThe production of NO in the PH group was twice as much as that in the Sham group. IL-1beta decreased the content of ATP and the KBR in the hepatocytes of both groups, and the decrease magni tude in the PH group was significantly larger than that in the Sham group. After the injection of L-arginine, the production of NO in the hepatocytes in the PH group increased, and the level of ATP and KBR decreased. N(G)-methyl-L-arginine (L-NMMA), the inhibitor of NO synthase, inhibited the production of NO and reversed the decrease of ATP and KBR.

CONCLUSIONAfter partial hepatectomy, increased NO production in the hepatocytes after the treatment of interleukin-1beta may disturb the function of mitochondria by inhibiting the synthesis of ATP.

Adenosine Triphosphate ; biosynthesis ; Animals ; Arginine ; pharmacology ; Cells, Cultured ; Hepatectomy ; Hepatocytes ; metabolism ; Interleukin-1beta ; pharmacology ; Ketone Bodies ; biosynthesis ; Nitric Oxide ; antagonists & inhibitors ; biosynthesis ; Nitric Oxide Synthase ; antagonists & inhibitors ; Rats ; omega-N-Methylarginine ; pharmacology

Recent studies have shown that astrocytes play important roles in ATP degradation and adenosine (a well known analgesic molecule) generation, which are closely related to pain signaling pathway. The aim of this study was to investigate whether morphine, a well known analgesic drug, could affect the speeds of ATP enzymolysis and adenosine generation in rat astrocytes. Intracellular calcium concentration ([Ca(2+)](i)) of astrocyte was measured by flow cytometry, and the time points that morphine exerted notable effects were determined for subsequent experiments. Cultured astrocytes were pre-incubated with morphine (1 μmol/L) and then were incubated with substrates, ATP and AMP, for 30 min. The speeds of ATP enzymolysis and adenosine generation were measured by high performance liquid chromatography (HPLC). The results showed that both 1.5 and 48 h of morphine pre-incubation induced maximal ATP enzymolysis speed in astrocytes among all the time points, and there was no statistical difference of ATP enzymolysis speed between morphine treatments for 1.5 and 48 h. As to adenosine, morphine pre-incubation for 1.5 h statistically increased adenosine generation, which was degraded from AMP, in cultured astrocytes compared with control group. However, no difference of adenosine generation was observed after 48 h of morphine pre-incubation. These results indicate that treatment of morphine in vitro dynamically changes the concentrations of ATP and adenosine in extracellular milieu of astrocytic cells. In addition, astrocyte can be regarded as at least one of the target cells of morphine to induce changes of ATP and adenosine levels in central nervous system.
Adenosine ; biosynthesis ; Adenosine Triphosphate ; metabolism ; Analgesics, Opioid ; pharmacology ; Animals ; Animals, Newborn ; Astrocytes ; cytology ; drug effects ; metabolism ; Calcium ; analysis ; metabolism ; Cells, Cultured ; Cerebral Cortex ; cytology ; Morphine ; pharmacology ; Rats ; Rats, Sprague-Dawley

Adenosine Triphosphate ; metabolism ; Animals ; Cordyceps ; Drugs, Chinese Herbal ; therapeutic use ; Fatty Liver ; drug therapy ; metabolism ; Female ; Ion Channels ; biosynthesis ; Liver ; metabolism ; Mitochondrial Proteins ; biosynthesis ; Phytotherapy ; Rats ; Rats, Sprague-Dawley ; Uncoupling Protein 2

OBJECTIVETo investigate the mechanism of K(ATP)-mediated protection of the hippocampal neurons exposed to hypoxia.

METHODSThe neurons were exposed to hypoxia (0% O(2), 5% CO(2) and 95% N(2)) or treated with tolbutamide or diazoxide for 12 or 24 h 1 week after seeding. MTT assay was used to measure the cell viability. RT-PCR was performed to detect Bax mRNA expression.

RESULTSMTT assay showed a much lower survival rate (75.7-/+2.8%) of the neurons exposed to severe hypoxia (PO(2)=0 mmHg) than that of the neurons in normoxia (P<0.01, n=7). Tolbutamide (100 micromol/L) treatment significantly reduced the survival rate of the neurons to (55.7-/+2.5)%, while diazoxide (100 micromol/L) increased the survival rate to 81.1-/+2.4)% (P<0.01, n=6). In normoxia, neither diazoxide nor tolbutamide significantly affected the cell viability (P>0.05, n=6). A significant increase in Bax (P<0.01) and Fas (P<0.01) mRNA expression occurred in the neurons exposed to severe hypoxia (PO(2)=0 mmHg) as compared with the expressions in cells in normoxia (PO(2)=144 mmHg). In the hypoxic neurons, tolbutamide significantly increased Bax mRNA expression(P<0.05), while diazoxide reduced the expression to a level comparable with that observed in normoxic condition. CONCLUSION Bax is involved in KATP-mediated protection of hippocampal neurons exposed to hypoxia.

Adenosine Triphosphate ; metabolism ; Animals ; Animals, Newborn ; Cell Hypoxia ; Cells, Cultured ; Hippocampus ; cytology ; metabolism ; Immunohistochemistry ; Neurons ; cytology ; metabolism ; Potassium Channels ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; bcl-2-Associated X Protein ; biosynthesis ; genetics