Full Text Available An LC-MS screening method was developed to detect the presence of atractyloside (ATR), the toxic principle of a commonly used medicinal plant in South Africa, Callilepis laureola, in biological matrices such as body fluids and human viscera...
Vignais, P.V.; Vignais, P.M.; Defaye, G.; Lauquin, G.; Doussiere, J.; Chabert, J.; Brandolin, G.
From international conference on mechanism in bioenergetica; Bari, Italy (1 May 1972). Two specific inhibitors of the adenine nucleotide translocation, gummiferin (GUM), identified to 4-carboxyatractyloside and atractyloside (ATR), were labeled with /sup 35/S and their binding properties to whole mitochondria and inner mitochondrial membrane vesicles used to monitor changes of membrane conformation induced by ADP. (auth)
Wickes, W.A.; Wiskich, J.T.
The uncoupling by arsenate of beetroot and cauliflower bud mitochondria showed the following characteristics: arsenate stimulation of respiration above the rate found with phosphate; inhibition of arsenate-stimulated respiration by phosphate; enhancement of arsenate-stimulated respiration by ADP; only partial prevention of this ADP-enhanced respiration by atractyloside; inhibition by oligomycin of the arsenate-stimulated respiration back to the phosphate rate; and the absence of any stimulatory effect of ADP in the presence of oligomycin. These results are qualitatively analogous to those reported for arsenate uncoupling in rat liver mitochondria. Arsenate stimulated malate oxidation, presumably by stimulating malate entry, in both beetroot and cauliflower bud mitochondria; however, high rates of oxidation, and presumably entry, were only sustained with arsenate in beetroot mitochondria. NADH was oxidized rapidly in cauliflower bud mitochondria in the presence of arsenate, showing that arsenate did not inhibit electron transfer processes.
Brand, M D; Lehninger, A L
The nature of the energy store causing rapid superstoichiometric leads to H+/2e minus ejection and leads to Ca2+/2e minus uptake ratios in rat liver mitochondria pulsed with Ca2+ has been investigated. The extent and the rate of the initial fast superstoichiometric phase of H plus ejection were greatly reduced by oligomycin and other ATPase inhibitors; the subsequent shoichiometric phase was unaffected. No such inhibition was seen with atractyloside. Similarly, the initial fast phase of Ca2+ uptake was reduced in extent by oligomycin, whereas the slower stoichiometric phase was unaffected. Moreover, the ATP content of mitochondria previously incubated with succinate decreased by about 80% within 5 s after pulsing with Ca2+. The energy store for superstoichiometric Ca2+ uptake and H plus injection is thus identified as endogenous ATP.
Pagel, Paul S; Krolikowski, John G; Shim, Yon Hee; Venkatapuram, Suneetha; Kersten, Judy R; Weihrauch, Dorothee; Warltier, David C; Pratt, Phillip F
The anesthetic noble gas, xenon, produces cardioprotection. We hypothesized that other noble gases without anesthetic properties [helium (He), neon (Ne), argon (Ar)] also produce cardioprotection, and further hypothesized that this beneficial effect is mediated by activation of prosurvival signaling kinases [including phosphatidylinositol-3-kinase, extracellular signal-regulated kinase, and 70-kDa ribosomal protein s6 kinase] and inhibition of mitochondrial permeability transition pore (mPTP) opening in vivo. Rabbits (n = 98) instrumented for hemodynamic measurement and subjected to a 30-min left anterior descending coronary artery (LAD) occlusion and 3 h reperfusion received 0.9% saline (control), three cycles of 70% He-, Ne-, or Ar-30% O2 administered for 5 min interspersed with 5 min of 70% N2-30% O2 before LAD occlusion, or three cycles of brief (5 min) ischemia interspersed with 5 min reperfusion before prolonged LAD occlusion and reperfusion (ischemic preconditioning). Additional groups of rabbits received selective inhibitors of phosphatidylinositol-3-kinase (wortmannin; 0.6 mg/kg), extracellular signal-regulated kinase (PD 098059; 2 mg/kg), or 70-kDa ribosomal protein s6 kinase (rapamycin; 0.25 mg/kg) or mPTP opener atractyloside (5 mg/kg) in the absence or presence of He pretreatment. He, Ne, Ar, and ischemic preconditioning significantly (P noble gases without anesthetic properties produce cardioprotection by activating prosurvival signaling kinases and inhibiting mPTP opening in rabbits.
Yoshida, Akemi; Asanuma, Hiroshi; Sasaki, Hideyuki; Sanada, Shoji; Yamazaki, Satoru; Asano, Yoshihiro; Shinozaki, Yoshiro; Mori, Hidezo; Shimouchi, Akito; Sano, Motoaki; Asakura, Masanori; Minamino, Tetsuo; Takashima, Seiji; Sugimachi, Masaru; Mochizuki, Naoki; Kitakaze, Masafumi
Inhalation of hydrogen (H(2)) gas has been shown to limit infarct size following ischemia-reperfusion injury in rat hearts. However, H(2) gas-induced cardioprotection has not been tested in large animals and the precise cellular mechanism of protection has not been elucidated. We investigated whether opening of mitochondrial ATP-sensitive K+ channels (mK(ATP)) and subsequent inhibition of mitochondrial permeability transition pores (mPTP) mediates the infarct size-limiting effect of H(2) gas in canine hearts. The left anterior descending coronary artery of beagle dogs was occluded for 90 min followed by reperfusion for 6 h. Either 1.3% H(2) or control gas was inhaled from 10 min prior to start of reperfusion until 1 h of reperfusion, in the presence or absence of either 5-hydroxydecanoate (5-HD; a selective mK(ATP) blocker), or atractyloside (Atr; a mPTP opener). Systemic hemodynamic parameters did not differ among the groups. Nevertheless, H(2) gas inhalation reduced infarct size normalized by risk area (20.6±2.8% vs. control gas 44.0±2.0%; pchannels followed by inhibition of mPTP. H(2) gas may provide an effective adjunct strategy in patients with acute myocardial infarction receiving reperfusion therapy.
Lang, Roman; Fromme, Tobias; Beusch, Anja; Wahl, Anika; Klingenspor, Martin; Hofmann, Thomas
Atractyloside (1) and carboxyatractyloside (2) are well-known inhibitors of the adenine nucleotide translocase (ANT) in mitochondria, thus effectively blocking oxidative phosphorylation. Structurally related derivatives atractyligenin (3), 2-O-β-D-glucopyranosyl-atractyligenin (4), 3'-O-β-D-glucopyranosyl-2'-O-isovaleryl-2β-(2-desoxy-atractyligenin)-β-D-glucopyranoside (5), and 2-O-β-D-glucopyranosyl-carboxyatractyligenin (6) were isolated from raw beans of Coffea L. and the impact of 1-6 on ANT activity was evaluated in isolated mitochondria. Among the coffee components, 6 significantly inhibited ANT activity leading to reduced respiration. Quantitative analysis in commercial coffees, experimental roastings of coffee, and model experiments using purified compound 6 consistently revealed a complete degradation during thermal treatment. In comparison, raw coffee extracts were found to contain high levels of 6, which are therefore expected to be present in food products enriched with raw coffee extracts. This implies the necessity of analytically controlling the levels of 6 in raw coffee extracts when used as additives for food products. Copyright © 2013 Elsevier Ltd. All rights reserved.
Kučera, Lukáš; Papoušek, Roman; Kurka, Ondřej; Barták, Petr; Bednář, Petr
Espresso coffee samples prepared at various roasting degrees defined according to its basic conventional classification (light, medium, medium-dark and dark roasted) were analyzed by ultra-performance liquid chromatography/tandem mass spectrometry. Obtained raw data were processed using multivariate statistical analysis (Principal Component Analysis, PCA) to evaluate chemical differences between each roasting degrees (untargeted part of study). All four roasting degrees were resolved in appropriate Score plot. Orthogonal Projections to Latent Structures provided signals of significant markers describing the differences among particular roasting degrees. Detailed interpretation of those signals by targeted LC/MS(2) analysis revealed four groups of compounds. The first two groups involve chlorogenic acids and related lactones. The signals of other two sets of markers were ascribed to some specific atractylosides and particular melanoidins. Ratios of contents of selected representatives of each group to the sum of all identified markers were proposed as definite parameters for determination of roasting degree of Brazilian coffee Arabica. Copyright © 2015 Elsevier Ltd. All rights reserved.
Fan, Yan-Ying; Shen, Zhe; He, Ping; Jiang, Lei; Hou, Wei-wei; Shen, Yao; Zhang, Xiang-Nan; Hu, Wei-Wei; Chen, Zhong
Acidosis is one of the key components in cerebral ischemic postconditioning that has emerged recently as an endogenous strategy for neuroprotection. We set out to test whether acidosis treatment at reperfusion can protect against cerebral ischemia/reperfusion injury. Adult male C57BL/6 J mice were subjected to 60-minute middle cerebral arterial occlusion followed by 24-hour reperfusion. Acidosis treatment by inhaling 10%, 20%, or 30% CO2 for 5 or 10 minutes at 5, 50, or 100 minutes after reperfusion was applied. Our results showed that inhaling 20% CO2 for 5 minutes at 5 minutes after reperfusion-induced optimal neuroprotection, as revealed by reduced infarct volume. Attenuating brain acidosis with NaHCO3 significantly compromised the acidosis or ischemic postconditioning-induced neuroprotection. Consistently, both acidosis-treated primary cultured cortical neurons and acute corticostriatal slices were more resistant to oxygen–glucose deprivation/reperfusion insult. In addition, acidosis inhibited ischemia/reperfusion-induced apoptosis, caspase-3 expression, cytochrome c release to cytoplasm, and mitochondrial permeability transition pore (mPTP) opening. The neuroprotection of acidosis was inhibited by the mPTP opener atractyloside both in vivo and in vitro. Taken together, these findings indicate that transient mild acidosis treatment at reperfusion protects against cerebral ischemia/reperfusion injury. This neuroprotection is likely achieved, at least partly, by inhibiting mPTP opening and mitochondria-dependent apoptosis. PMID:24192637
Full Text Available The mitochondrial phosphate transporter (MPT plays crucial roles in ATP production in plant cells. Three MPT genes have been identified in Arabidopsis thaliana. Here we report that the mRNA accumulations of AtMPTs were up-regulated by high salinity stress in A. thaliana seedlings. And the transgenic lines overexpressing AtMPTs displayed increased sensitivity to salt stress compared with the wild-type plants during seed germination and seedling establishment stages. ATP content and energy charge was higher in overexpressing plants than those in wild-type A. thaliana under salt stress. Accordingly, the salt-sensitive phenotype of overexpressing plants was recovered after the exogenous application of atractyloside due to the change of ATP content. Interestingly, Genevestigator survey and qRT-PCR analysis indicated a large number of genes, including those related to gibberellin synthesis could be regulated by the energy availability change under stress conditions in A. thaliana. Moreover, the exogenous application of uniconazole to overexpressing lines showed that gibberellin homeostasis was disturbed in the overexpressors. Our studies reveal a possible link between the ATP content mediated by AtMPTs and gibberellin metabolism in responses to high salinity stress in A. thaliana.
Yang, Guodong; Wu, Changai; Huang, Jinguang; Zheng, Chengchao
The mitochondrial phosphate transporter (MPT) plays crucial roles in ATP production in plant cells. Three MPT genes have been identified in Arabidopsis thaliana. Here we report that the mRNA accumulations of AtMPTs were up-regulated by high salinity stress in A. thaliana seedlings. And the transgenic lines overexpressing AtMPTs displayed increased sensitivity to salt stress compared with the wild-type plants during seed germination and seedling establishment stages. ATP content and energy charge was higher in overexpressing plants than those in wild-type A. thaliana under salt stress. Accordingly, the salt-sensitive phenotype of overexpressing plants was recovered after the exogenous application of atractyloside due to the change of ATP content. Interestingly, Genevestigator survey and qRT-PCR analysis indicated a large number of genes, including those related to gibberellin synthesis could be regulated by the energy availability change under stress conditions in A. thaliana. Moreover, the exogenous application of uniconazole to overexpressing lines showed that gibberellin homeostasis was disturbed in the overexpressors. Our studies reveal a possible link between the ATP content mediated by AtMPTs and gibberellin metabolism in responses to high salinity stress in A. thaliana. PMID:22937061
Lin, Guo-Hua; Lin, Lin; Liang, Hua-Wei; Ma, Xin; Wang, Jing-Ye; Wu, Li-Ping; Jiang, Hui-Di; Bruce, Iain C; Xia, Qiang
The present study evaluated the potential neuroprotective effect and underlying mechanism of the total flavones extracted from Chrysanthemum morifolium (TFCM) against ischemia/reperfusion (I/R) injury. An animal model of cerebral ischemia was established by occluding the right middle cerebral artery for 90 minutes followed by reperfusion for 22 hours. The neurobehavioral scores, infarct area, and hemispheric edema were evaluated. The superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and reactive oxygen species (ROS) level in brain were also measured. The results showed that pretreatment with TFCM significantly decreased the neurological deficit scores, percentage of infarction, and brain edema and attenuated the decrease in SOD activity, the elevation of MDA content, and the generation of ROS. In isolated brain mitochondria, Ca(2+)-induced swelling was attenuated by pretreatment with TFCM, and this effect was antagonized by atractyloside. These results showed that pretreatment with TFCM provides significant protection against cerebral I/R injury in rats by, at least in part, its antioxidant action and consequent inhibition of mitochondrial swelling.
Full Text Available The mitochondrial cascade hypothesis of dementia assumes mitochondrial dysfunction leading to reduced energy supply, impaired neuroplasticity, and finally cell death as one major pathomechanism underlying the continuum from brain aging over mild cognitive impairment to initial and advanced late onset Alzheimer’s disease. Accordingly, improving mitochondrial function has become an important strategy to treat the early stages of this continuum. The metabolic enhancer piracetam has been proposed as possible prototype for those compounds by increasing impaired mitochondrial function and related aspects like mechanisms of neuroplasticity. We here report that piracetam at therapeutically relevant concentrations improves neuritogenesis in the human cell line SH-SY5Y over conditions mirroring the whole spectrum of age-associated cognitive decline. These effects go parallel with improvement of impaired mitochondrial dynamics shifting back fission and fusion balance to the energetically more favorable fusion site. Impaired fission and fusion balance can also be induced by a reduction of the mitochondrial permeability transition pore (mPTP function as atractyloside which indicates the mPTP has similar effects on mitochondrial dynamics. These changes are also reduced by piracetam. These findings suggest the mPTP as an important target for the beneficial effects of piracetam on mitochondrial function.
Landry, Y; Lehninger, A L
Ehrlich ascites-tumour cells accumulate Ca2+ when incubated aerobically with succinate, phosphate and rotenone, as revealed by isotopic and atomic-absorption measurements. Ca2+ does not stimulate oxygen consumption by carefully prepared Ehrlich cells, but des so when the cells are placed in a hypo-osmotic medium. Neither glutamate nor malate support Ca2+ uptake in 'intact' Ehrlich cells, nor does the endogenous NAD-linked respiration. Ca2+ uptake is completely dependent on mitochondrial energy-coupling mechansims. It was an unexpected finding that maximal Ca2+ uptake supported by succinate requires rotenone, which blocks oxidation of enogenous NAD-linked substrates. Phosphate functions as co-anion for entry of Ca2+. Ca2+ uptake is also supported by extra-cellular ATP; no other nucleoside 5'-di- or tri-phosphate was active. The accumulation of Ca2+ apparently takes place in the mitochondria, since oligomycin and atractyloside inhibit ATP-supported Ca2+ uptake. Glycolysis does not support Ca2+ uptake. Neither free mitochondria released from disrupted cells nor permeability-damaged cells capable of absorbing Trypan Blue were responsible for any large fraction of the total observed energy-coupled Ca2+ uptake. The observations reported also indicate that electron flow through energy-conserving site 1 promotes Ca2+ release from Ehrlich cells and that extra-cellular ATP increase permeability of the cell membrane, allowing both ATP and Ca2+ to enter the cells more readily. PMID:988829
Full Text Available Mitochondrial membrane potential is the major regulator of mitochondrial functions, including coupling efficiency and production of reactive oxygen species (ROS. Both functions are crucial for cell bioenergetics. We previously presented evidences for a specific modulation of adenine nucleotide translocase (ANT appearing during aging that results in a decrease in membrane potential - and therefore ROS production – but surprisingly increases coupling efficiency under conditions of low ATP turnover. Careful study of the bioenergetic parameters (oxidation and phosphorylation rates, membrane potential of isolated mitochondria from skeletal muscles (gastrocnemius of aged and young rats revealed a remodeling at the level of the phosphorylation system, in the absence of alteration of the inner mitochondrial membrane (uncoupling or respiratory chain complexes regulation. We further observed a decrease in mitochondrial affinity for ADP in aged isolated mitochondria, and higher sensitivity of ANT to its specific inhibitor atractyloside. This age-induced modification of ANT results in an increase in the ADP concentration required to sustain the same ATP turnover as compared to young muscle, and therefore in a lower membrane potential under phosphorylating - in vivo - conditions. Thus, for equivalent ATP turnover (cellular ATP demand, coupling efficiency is even higher in aged muscle mitochondria, due to the down-regulation of inner membrane proton leak caused by the decrease in membrane potential. In the framework of the radical theory of aging, these modifications in ANT function may be the result of oxidative damage caused by intra mitochondrial ROS and may appear like a virtuous circle where ROS induce a mechanism that reduces their production, without causing uncoupling, and even leading in improved efficiency. Because of the importance of ROS as therapeutic targets, this new mechanism deserves further studies.
Patogênese, sinais clínicos e patologia das doenças causadas por plantas hepatotóxicas em ruminantes e eqüinos no Brasil Pathogenesis, clinical signs and pathology of diseases caused by hepatotoxic plants in ruminants and horses in Brazil
Julio Cesar A. Santos
Full Text Available Plantas que causam lesões hepáticas em ruminantes e eqüinos constituem um grupo importante de plantas tóxicas no Brasil. Em geral essas plantas podem ser divididas em três grandes grupos: plantas que causam necrose hepática aguda; plantas que causam fibrose hepática; e plantas que causam fotossensibilização. Em algumas dessas plantas os princípios tóxicos já foram identificados. Das plantas que causam necrose hepática aguda, os carboxiatractilosídeos estão presentes em Cestrum parqui e Xanthium cavanillesi. Os alcalóides pirrolizidínicos estão presentes nas plantas que causam fibrose hepática (Senecio spp., Echium plantagineum, Heliotropum spp. e Crotalaria spp.. Das plantas que causam fotossensibilização hepatógena são conhecidos os furanossesquiterpenos em Myoporum spp., triterpenos em Lantana spp., e saponinas esteroidais em Brachiaria spp. e Panicum spp. O quadro clínicopatológico dessas intoxicações e o mecanismo geral da insuficiência hepática, incluindo meios de diagnóstico, são descritos neste artigo de revisão.Plants causing hepatic lesions in ruminants and horses constitute one important group of poisonous plants in Brazil. These plants can be placed in three major groups: plants causing acute liver necrosis; plants causing liver fibrosis; and plants causing hepatogenous photosensitization. For some of these plants the toxic principles are known. Cestrum parqui and Xanthium cavanillesi that cause acute liver necrosis contain carboxy-atractylosides. Senecio spp., Crotalaria spp., and Echium plantagineum that cause liver fibrosis contain pyrrolizidine alkaloids. As for the group of plants causing hepatogenous photosensibilization, Myoporum spp. contain furanosesquiterpenes, Lantana spp contain triterpenes, and Brachiaria spp. and Panicum spp. contain steroidal saponins. The clinical and pathologic features of the toxicosis caused by these phytotoxins, general mechanisms of production for the production of
Zhang, Li-Min; Zhang, Dong-Xue; Zhao, Xiao-Chun; Sun, Wen-Bo; Jiang, Xiao-Jing
As an indispensable clinical inhalation anesthetic, sevoflurane is widely used for peri-operative sedation. The neuroprotective effect of sevoflurane pre-conditioning against cerebral ischemia/reperfusion has been gradually realized, but the underlying mechanism during the early reperfusion period has not been established. Primary cultured cortical neurons were treated with 2% sevoflurane pre-conditioning for 30min, exposed to oxygen-glucose deprivation for 90min, and followed by 60min of reperfusion (OGD/R). Additionally, neuronal cells were treated with an inhibitor of extracellular signal-related kinases 1 and 2 (Erk1/2) phosphorylation (PD98059), a mPTP opener (atractyloside), or a mPTP opening inhibitor (cyclosporine A) before sevoflurane pre-conditioning. Sevoflurane pre-conditioning decreased neuronal apoptosis (assessed by TUNEL), oxidative stress (assessed by malondialdehyde [MDA], superoxide dismutase [SOD], and heme oxygenase [HO]-1), and opening of mitochondrial permeability transition pores [mPTPs] (assessed by calcein-cobalt), but increased neuronal viability (assessed by MTT) and mitochondrial membrane potential (assessed by JC-1) after OGD/R exposure compared with OGD/R treatment alone. Pre-treatment with the mPTP opener and inhibitor of Erk1/2 phosphorylation abolished the protective effect induced by sevoflurane pre-conditioning. Pre-treatment with the mPTP opener attenuated the phosphorylation of Erk1/2 in mitochondria of neuronal cultures exposed to OGD/R induced by sevoflurane pre-conditioning. The mPTP opening inhibitor, like sevoflurane pre-conditioning, increased phosphorylation of Erk1/2 after OGD/R exposure, while PD98059 failed to reverse inhibition of mPTP opening in cultures exposed to OGD/R induced by sevoflurane pre-conditioning. The neuroprotective mechanism of sevoflurane pre-conditioning might be associated with increased Erk1/2 phosphorylation in mitochondria via inhibition of mPTP opening in the early reperfusion period
Lai, Zhongmeng; Zhang, Liangcheng; Su, Jiansheng; Cai, Dongmiao; Xu, Qingxiu
Volatile anesthetic postconditioning has been documented to provide neuroprotection in adult animals. Our aim was to investigate whether sevoflurane postconditioning improves long-term learning and memory of neonatal hypoxia-ischemia brain damage (HIBD) rats, and whether the PI3K/Akt pathway and mitochondrial permeability transition pore (mPTP) opening participate in the effect. Seven-day-old Sprague-Dawley rats were subjected to brain HI and randomly allocated to 10 groups (n=24 each group) and treated as follows: (1) Sham, without hypoxia-ischemia; (2) HI/Control, received cerebral hypoxia-ischemia; (3) HI+Atractyloside (Atr), (4) HI+Cyclosporin A (CsA), (5) HI+sevoflurane (Sev), (6) HI+Sev+ LY294002 (LY), (7) HI+Sev+ L-NAME (L-N), (8) HI+Sev+ SB216763 (SB), (9) HI+Sev+Atr, and (10) HI+Sev+CsA. Twelve rats in each group underwent behavioral testing and their brains were harvested for hippocampus neuron count and morphology study. Brains of the other 12 animals were harvested 24h after intervention to examine the expression of Akt, p-Akt, eNOS, p-eNOS, GSK-3β, p-GSK-3β by Western bolting and mPTP opening. Sevoflurane postconditioning significantly improved the long-term cognitive performance of the rats, increased the number of surviving neurons in CA1 and CA3 hippocampal regions, and protected the histomorphology of the left hippocampus. These effects were abolished by inhibitors of PI3K/eNOS/GSK-3β. Although blocking mPTP opening simulated sevoflurane postconditioning-induced neuroprotection, it failed to enhance it. Sevoflurane postconditioning exerts a neuroprotective effect against HIBD in neonatal rats via PI3K/Akt/eNOS and PI3K/Akt/GSK-3β pathways, and blockage of mPTP opening may be involved in attenuation of histomorphological injury. Copyright © 2015 Elsevier B.V. All rights reserved.