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1.
Waldina P. Reyes-Velázquez Rosa M. Figueroa-Gómez Mauricio Barberis María Marta Reynoso Federico G. A. Rojo Sofía N. Chulze Adriana M. Torres 《Mycotoxin Research》2011,27(3):187-194
Fusarium species can produce fumonisins (FBs), fusaric acid, beauvericin (BEA), fusaproliferin (FUS) and moniliformin. Data on the
natural occurrence of FBs have been widely reported, but information on BEA and FUS in maize is limited. The aims of this
study were to establish the occurrence of Fusarium species in different maize hybrids in Mexico, to determine the ability of Fusarium spp. isolates to produce BEA, FUS and FBs and their natural occurrence in maize. Twenty-eight samples corresponding to seven
different maize hybrids were analyzed for mycobiota and natural mycotoxin contamination by LC. Fusarium verticillioides was the dominant species (44–80%) followed by F. subglutinans (13–37%) and F. proliferatum (2–16%). Beauvericin was detected in three different hybrids with levels ranging from 300 to 400 ng g−1, while only one hybrid was contaminated with FUS (200 ng g−1). All samples were positive for FB1 and FB2 contamination showing levels up to 606 and 277 ng g−1, respectively. All F. verticillioides isolates were able to produce FB1 (13.8–4,860 μg g−1) and some also produced FB2 and FUS. Beauvericin, FUS, FB1 and FB2 were produced by several isolates including F. proliferatum and F. subglutinans and co-production was observed. This is the first report on the co-occurrence of these toxins in maize samples from Mexico.
The analysis of the presence of multiple mycotoxins in this substrate is necessary to understand the significance of these
compounds in the human and animal food chains. 相似文献
2.
The Fusarium metabolite enniatin B is now recognized as a frequent contaminant of grains used for human foods and animal feeds. Yet, so
far very limited data are available on its toxicity and that of other emerging Fusarium mycotoxins (Jestoi M, 2008, Crit Rev Food Sci Nutr 48:21-49). Thus, the mutagenic/genotoxic potential of enniatin B was investigated
in a battery of short-term tests, and its cytotoxicity compared with that of several other mycotoxins. No mutagenicity was
detected in the Ames assay with four Salmonella typhimurium strains, and in the HPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 cells, in either the presence or
absence of an external metabolizing enzyme system (rat liver S9). For other types of genotoxicity, i.e., clastogenicity and
chromosomal damage, studied in V79 cells by means of alkaline single-cell gel electrophoresis (Comet) assay and micronucleus
assay, no significant genotoxic potential of enniatin B was revealed. However, the Fusarium metabolite exerts pronounced time- and concentration-dependent cytotoxic effects in V79 cells as determined by Alamar Blue
reduction and by neutral red uptake assays. For instance, IC20 and IC50 values determined for enniatin B by neutral red assay for 48-h exposure are 1.5 μM and 4 μM. These values are higher than
those of the more potent Fusarium toxin deoxynivalenol (IC20 0.7 μM, IC50 of 0.8 μM), but clearly lower than the IC values of several other mycotoxins tested in parallel. Their ranking of cytotoxicity
in V79 cells was as follows: deoxynivalenol > enniatin B > patulin > ochratoxin A > zearalenone > citrinin. Moreover, enniatin
B was found to induce nuclear fragmentation, a sign of apoptosis, already at low submicromolar concentrations. In summary,
despite an apparent lack of mutagenic and genotoxic activity, enniatin B can cause pronounced cytotoxicity in mammalian cells,
detectable at low micromolar concentrations. 相似文献
3.
Stimulation of menthol production in <Emphasis Type="Italic">Mentha piperita</Emphasis> cell culture 总被引:1,自引:0,他引:1
Amrita Chakraborty Sharmila Chattopadhyay 《In vitro cellular & developmental biology. Plant》2008,44(6):518-524
Plant cell culture provides an alternative means for producing secondary metabolites. In this study, experiments were carried
out to study the impact of several parameters, independently and in combination, on the stimulation of menthol production
in the cell suspension culture of Mentha piperita. Callus was obtained from leaf segments of in vitro grown plantlets on Murashige and Skoog (MS) medium supplemented with 0.2 mg l−1of 2,4-dichlorophenoxy acetic acid to initiate cell suspension culture. This culture was maintained in half-strength MS medium
supplemented with 0.2 mg l−1of 2,4-dichlorophenoxy acetic acid at 15 d interval and used for further studies. Precursor feeding alone, i.e., menthone,
at 35 μM concentration showed slightly improved productivity. γ-Cyclodextrin alone at 60 μM concentration and in combination
with menthone feeding at 35 μM increased menthol yield up to 92 and 110 mg l−1 in comparison to 77 mg l−1 of control culture. Synergistic potentiation effect of menthone feeding at 35 μM and γ-cyclodextrin at 60 μM treatment followed
by in situ adsorption with RP-8 also showed potential stimulation of menthol production in M. piperita cell culture. Fungal elicitor treatment showed enhanced production level up to 140.8 mg l−1 in comparison to that of control. Further studies were carried out with the establishment of Agrobacterium tumefaciens (Ach5) gall-mediated calli, and consequently, cell suspension culture and results showed the significant enhancement of menthol
yield up to 278 mg l−1.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
Waraporn Putalun Orapin Udomsin Gorawit Yusakul Thaweesak Juengwatanatrakul Seiichi Sakamoto Hiroyuki Tanaka 《Biotechnology letters》2010,32(5):721-724
Methyl jasmonate, 50 μM, 0.5 mg yeast extract/l and 100 mg chitosan/l stimulated plumbagin production in Drosera burmanii whole plant cultures after 6 days of elicitation. Yeast extract (0.5 mg/l) was the most efficient enhancing plumbagin production
in roots of D. burmanii to 8.8 ± 0.5 mg/g dry wt that was 3.5-fold higher than control plants. 相似文献
5.
The entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin is known to produce a broad range of secondary metabolites. Beauvericin, a cyclic hexadepsipeptide, is the best known mycotoxin produced by B. bassiana; however, reports discussing the insecticidal activity of beauvericin per se are limited. In this study, we assessed the lethal activity of beauvericin against Tetranychus urticae Koch (Acarina: Tetranychidae). In addition, screening for suitable application of the mycotoxin against T. urticae on greenhouse strawberries is discussed. Beauvericin was able to control successfully T. urticae where concentrations of 10, 100 and 1,000 µg/g recorded mortalities of 84%, 100% and 100%, respectively, against motile stages. Furthermore, beauvericin inhibited egg hatching up to 83.3%, 69.3% and 53.3%, respectively, using the same concentrations under laboratory conditions. Under greenhouse conditions, the efficacy recorded was 52.6%, 85.7%, 72.4% and 72.4% at 1, 3, 7 and 10 days post‐inoculation, respectively. Beauvericin was efficacious under greenhouse conditions since the application increased strawberry yields while showing no phytotoxicity and ecotoxicological risk. Resistance to beauvericin was not detected initially at the unselected strain of T. urticae. Yet, the laboratory selection of populations of T. urticae exposed to beauvericin resulted in relatively resistant T. urticae strain that displayed no cross‐resistance to cyflumetofen and bifenazate. The acaricidal activity of beauvericin documented in this study would increase the efficacy of integrated pest management strategies. 相似文献
6.
Simultaneous analysis of beauvericin and moniliformin in fungal cultures and in cereal grain samples
Species ofFusarium subglutinans andFusarium proliferation have been found to produce two mycotoxins, beauvericin and moniliformin, under labolatory conditions as well as in infected
ears. A method for simultaneous extraction, analysis and quantitation of both metabolites was elaborated. Recoveries were
85–97 % and 78–94 % for the first and the latter mycotoxin, respectively. Detection limit of beauvericin on high- performance
thin- layer chromatography plates (Merck 5633) after exposure to iodine vapours was 3 μg/g and by high- performance liquid
chromatography method 0.07 μg/g while moniliformin was analyzed at concentration level 1 μg/g by thin- layer chromatography
and 0.05 μg/g by high- performance liquid chromatography method. 相似文献
7.
The effects of cadmium (Cd) on germination, and antioxidative enzyme activity (AEA) involving superoxide dismutase, catalase,
peroxidase, and ascorbate peroxidase, and on amounts of malondialdehyde and proline present within Achnatherum inebrians, were determined for specimens infected (E+) vs. non-infected (E−) by Neotyphodium gansuense, and cultivated in the presence of various concentrations of CdCl2 (0, 50, 100, 200 and 300 μmol/l). Under high Cd concentrations (100, 200 and 300 μM), E+ (vs. E−) specimens exhibited a higher
germination rate and index, and higher values for shoot length, root length and dry biomass, but there was no significant
difference (P > 0.05) under low Cd concentrations (0 and 50 μM). AEA and the proline content increased, but malondialdehyde content declined
in the E+ (vs. E−) specimens under high Cd concentrations (100, 200 and 300 μM). There was no significant difference (P > 0.05) under low Cd concentrations (0 and 50 μM). Endophyte infection was concluded to be of benefit to the germination
and anti-oxidative mechanisms within A. inebrians under plant exposures to high CdCl2 concentrations. 相似文献
8.
9.
In vitro propagation of northern red oak (Quercus rubra) shoots was successful from cotyledonary node explants excised from 8-wk-old in vitro grown seedlings. Initially, four shoots per explant were obtained on Murashige and Skoog (MS) medium supplemented with 4.4 μM
6-benzylaminopurine (BA), 0.45 μM thidiazuron (TDZ), and 500 mg l−1 casein hydrolysate (CH) with a regeneration frequency of 64.7% after 3 wk. Subculturing explants (after harvesting shoots)
to fresh treatment medium significantly increased shoot bud regeneration (16.6 buds per explant), but the buds failed to develop
into shoots. A higher percentage (73.3%) of the explants regenerated four shoots per explant on woody plant medium (WPM) supplemented
with 4.4 μM BA, 0.29 μM gibberellic acid (GA3), and 500 mg l−1 CH after 3 wk. Explants subcultured to fresh treatment medium after harvesting shoots significantly increased shoot regeneration
(16 shoots per explant). Shoot elongation was achieved (4 cm) when shoots were excised and cultured on WPM supplemented with
0.44 μM BA and 0.29 μM GA3. In vitro regenerated shoots were rooted on WPM supplemented with 4.9 μM indole-3-butyric acid. A higher percentage regeneration response
and shoot numbers per explant were recorded on WPM supplemented with BA and GA3, than on MS medium containing BA and TDZ. Lower concentrations of BA and GA3 were required for shoot elongation and prevention of shoot tip necrosis. Each cotyledonary node yielded approximately 20
shoots within 12 wk. Rooted plantlets were successfully acclimatized. 相似文献
10.
Berbert-Molina MA Prata AM Pessanha LG Silveira MM 《Journal of industrial microbiology & biotechnology》2008,35(11):1397-1404
The kinetic and general growth features of Bacillus thuringiensis var. israelensis were evaluated. Initial glucose concentration (S
0) in fermentation media varied from 10 to 152 g/l. The results afforded to characterize four morphologically and physiologically
well-defined culture phases, independent of S
0 values: Phase I, vegetative growth; Phase II, transition to sporulation; Phase III, sporulation; and Phase IV, spores maturation
and cell lysis. Important process parameters were also determined. The maximum specific growth rates (μ
X,m) were not affected with S
0 up to 75 g/l (1.0–1.1 per hour), but higher glucose concentrations resulted in growth inhibition by substrate, revealed by
a reduction in μ
X,m values. These higher S
0 values led to longer Phases III and IV and delayed sporulation. Similar biomass concentrations (X
m = 15.2–15.9 g/l) were achieved with S
0 over 30.8 g/l, with increasing residual substrate, suggesting a limitation in some other nutrients and the use of glucose
to form other metabolites. In this case, with S
0 from 30.8 to 152 g/l, cell yield (Y
X/S
) decreased from 0.58 to 0.41 g/g. On the other hand, with S
0 = 10 g/l growth was limited by substrate, and Y
X/S
has shown its maximum value (0.83 g/g). 相似文献
11.
The metabolites produced by Stigmatella WXNXJ-B inhibited the growth of tumor cells. The aims of this research were to evaluate the inhibition potency to different
tumor cell lines and to study the effects of ammonium, phosphate and iron salts on bacterial growth and production of bioactive
metabolites in Stigmatella WXNXJ-B fermentation. The results showed that the chloroform extract (CE-ME) showed the strongest growth inhibition bioactivity
on mouse melanoma cell line (B16), murine colon carcinoma cell line (CT-26), human liver carcinoma cell line (HepG2) and human
breast cancer cell line (MDA-MB231) in vitro and the IC50 values were 9.94, 7.33, 11.34 and 11.66 μg ml−1 respectively. The IC50 value was above 700 μg ml−1 on normal mouse spleen cells. Morphology happened changes in B16 cells treated with CE-ME. The anti-tumor metabolites were
mainly produced during the stationary phase of the bacterial growth. Cell growth was stimulated at the phosphate concentration
below 5 mM, but it was inhibited partly with 10 mM phosphate. The production of bioactive substances was inhibited by the
phosphate. Ammonium increased the cell growth by 250% at 5 mM addition. The inhibition rate to B16 cells was increased to
89% at the concentration of 40 mM ammonium. The bacteria showed the best growth with 4 mM iron. Iron had little effect on
the production at 2 mM, but bigger inhibition effect at higher iron concentration. 相似文献
12.
M. E. Estrada-Zúñiga F. Cruz-Sosa M. Rodríguez-Monroy J. R. Verde-Calvo E. J. Vernon-Carter 《Plant Cell, Tissue and Organ Culture》2009,97(1):39-47
Plant tissue cultures represent a potential source for producing secondary metabolites. In this work, Buddleja cordata tissue cultures were established in order to produce phenylpropanoids (verbascoside, linarin and hydroxycinnamic acids),
as these metabolites are credited with therapeutic properties. Highest callus induction (76.4–84.3%) was obtained in five
treatments containing 2,4-Dichlorophenoxyacetic acid (2,4-d: 0.45–9.05 μM) with Kinetin (KIN: 2.32, 4.65 μM), whereas highest root induction (79.6%) corresponded to the α-Naphthaleneacetic
acid (9.05 μM) with KIN (2.32 μM) treatment. Verbascoside was the major phenylpropanoid produced in in vitro cultures (root,
white and green callus) [66.24–86.26 mg g−1 dry weight (DW)], while linarin and hydroxycinnamic acid production was low (0.95–3.01 mg g−1 DW). Verbascoside and linarin production were improved in cell suspension culture (116 mg g−1 DW and 8.12 mg g−1 DW, respectively). 相似文献
13.
14.
B. Vinterhalter T. Janković K. Šavikin R. Nikolić D. Vinterhalter 《Plant Cell, Tissue and Organ Culture》2008,94(3):329-335
Shoot cultures of Gentianella austriaca (A. & J. Kerner) Dostal established from seedling epicotyls were maintained on MS medium supplemented with 2.22 μM BA and
0.54 μM NAA. A characteristic feature of these cultures was precocious flowering, which appeared in all rapidly elongating
shoots. Flower development arrested shoot elongation and multiplication of shoot cultures. Continuous shoot propagation was
possible only by use of small axillary or adventitious buds as explants for subculturing. Flowering could not be suppressed
by GA3 addition or by cultivation in short-day conditions. The highest rooting percentage (47.3% with 7.83 roots per explant) was
achieved on media with 4.92 μM IBA. Shoot cultures contained the same types of secondary metabolites as plants from nature.
Xanthones were the major constituents, with DMB (demethylbellidifolin), DGL (demethylbellidifolin-8-O-glucoside) and BGL (bellidifolin-8-O-glucoside) present at roughly two times lower concentrations than in samples from nature. Secondary metabolite production
was strongly affected by the presence of BA in the medium. 相似文献
15.
S. F. Baldia A. D. Evangelista E. V. Aralar A. E. Santiago 《Journal of applied phycology》2007,19(6):607-613
Phytoplankton supports fisheries and aquaculture production. Its vital role as food for aquatic animals, like mollusks, shrimp,
and fish cannot be overemphasized. Because of its contribution as a food source for fish, the growth kinetics of Microcystis aeruginosa, a dominant cyanobacterium in the lake, was studied. The regular occurrence of M. aeruginosa is experienced during the months of May to July or from September to November in Laguna de Bay, the largest freshwater lake
in the Philippines. M. aeruginosa was collected from Laguna de Bay, isolated, and established in axenic conditions. Data on the growth kinetic parameters for
nitrate-nitrogen and phosphate-phosphorus utilization by M. aeruginosa gave the following values: half-saturation constant (K
s
), 0.530 mg N. L−1 and 0.024 mg P. L−1 respectively; maximum growth rate (μ
max
), 0.671. d−1 and 0.668. d−1 respectively; maximum cell yield, 6.5 and 6.54 log, cells. ml−1 respectively; nutrient level for saturated growth yield, 8.71 mg N. L−1 and 0.22 mg P. L−1 respectively; and minimum cell quota (Q
0
), 2.82 pg N. cell−1 and 0.064 pg P. cell−1 respectively. The low K
s value and high maximum growth rate (μ
max
) for phosphorus by M. aeruginosa would suggest a high efficiency of phosphorus utilization. On the other hand, the high K
s
value for nitrogen indicated a low rate of uptake for this nutrient. 相似文献
16.
Abbas HK Cartwright RD Xie W Mirocha CJ Richard JL Dvorak TJ Sciumbato GL Shier WT 《Mycopathologia》1999,147(2):97-104
Twenty samples of unpolished (rough) rice collected in Arkansas and Texas during the 1995 harvesting season from fields exhibiting
Fusarium sheath rot disease or panicle blight were previously shown to include 8 samples positive for fumonisin B1(FB1) in the range 2.2–5.2 ppm, and moniliformin (MON), but no beauvericin (BEA), deoxynivalenol, its derivatives or zearalenone
were detected. Fifteen cultures of F. proliferatum were established from the 20 rough rice samples. Single spore isolates of each culture were grown on rice and tested for
the production of fumonisins (FB1, FB2, FB3, etc.), MON and BEA. All 15 isolates produced FB1, FB2, MON and BEA in culture on rice. No deoxynivalenol, its derivatives orzearalenone were detected. Seven cultures produced
FB1 at >50ppm (range 80–230 ppm), with therest producing FB1 in the range 14–43 ppm.FB2 was produced in the range 5–47 ppm, and those cultures which produced the most FB1 also produced the most FB2. Of the 15 cultures producing MON, 11 produced it at >100 ppm in the range 188–6018 ppm, with the rest producing in the range
7–64 ppm. BEA was produced in the range 109–1350 ppm. Other derivatives of fumonisins, including FA1, FA2 and partially hydrolyzed FB1, as well asseveral unknown metabolites including a compound with MW 414, were identified in culture extracts by continuous
flow fast atom bombardment with ion spraymass spectrometry (CF/FAB/MS). Further study is needed to identify the factors that
control production of FB1, MON and BEA by F.proliferatu in culture and in field samples.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Hemant Lata Suman Chandra Ikhlas Khan Mahmoud A. ElSohly 《In vitro cellular & developmental biology. Plant》2009,45(1):12-19
Induction of high-frequency shoot regeneration using nodal segments containing axillary buds from a 1-yr-old mother plants
of Cannabis sativa was achieved on Murashige and Skoog (MS) medium containing 0.05–5.0 μM thidiazuron. The quality and quantity of regenerants
were better with thidiazuron (0.5 μM thidiazuron) than with benzyladenine or kinetin. Adding 7.0 μM of gibberellic acid into
a medium containing 0.5 μM thidiazuron slightly increased shoot growth. Elongated shoots when transferred to half-strength
MS medium supplemented with 500 mg l−1 activated charcoal and 2.5 μM indole-3-butyric acid resulted in 95% rooting. The rooted plants were successfully acclimatized
in soil. Following acclimatization, growth performance of 4-mo-old in vitro propagated plants was compared with ex vitro vegetatively grown plants of the same age. The photosynthesis and transpiration characteristics were studied under different
light levels (0, 500, 1,000, 1,500, or 2,000 μmol m−2 s−1). An increase in photosynthesis was observed with increase in the light intensity up to 1,500 μmol m−2 s−1 and then decreased subsequently at higher light levels in both types of plants. However, the increase was more pronounced
at lower light intensities below 500 μmol m−2 s−1. Stomatal conductance and transpiration increased with light intensity up to highest level (2000 μmol m−2 s−1) tested. Intercellular CO2 concentration (C
i) and the ratio of intercellular CO2 concentration to ambient CO2 (C
i/C
a) decreased with the increase in light intensity in both in vitro as well as ex vitro raised plants. The results show that in vitro propagated and hardened plants were functionally comparable to ex vitro plants of same age in terms of gas and water vapor exchange characteristics, within the limits of this study. 相似文献
18.
Two fungal cyclooligomer depsipeptide synthetases (CODSs), BbBEAS (352 kDa) and BbBSLS (348 kDa) from Beauveria bassiana ATCC 7159, were reconstituted in Saccharomyces cerevisiae BJ5464-NpgA, leading to the production of the corresponding anticancer natural products, beauvericins and bassianolide, respectively. The titers of beauvericins (33.8±1.4 mg/l) and bassianolide (21.7±0.1 mg/l) in the engineered S. cerevisiae BJ5464-NpgA strains were comparable to those in the native producer B. bassiana. Feeding d-hydroxyisovaleric acid (d-Hiv) and the corresponding l-amino acid precursors improved the production of beauvericins and bassianolide. However, the high price of d-Hiv limits its application in large-scale production of these cyclooligomer depsipeptides. Alternatively, we engineered another enzyme, ketoisovalerate reductase (KIVR) from B. bassiana, into S. cerevisiae BJ5464-NpgA for enhanced in situ synthesis of this expensive substrate. Co-expression of BbBEAS and KIVR in the yeast led to significant improvement of the production of beauvericins. The total titer of beauvericin and its congeners (beauvericins A–C) was increased to 61.7±3.0 mg/l and reached 2.6-fold of that in the native producer B. bassiana ATCC 7159. Supplement of l-Val at 10 mM improved the supply of ketoisovalerate, the substrate of KIVR, which consequently further increased the total titer of beauvericins to 105.8±2.1 mg/l. Using this yeast system, we functionally characterized an unknown CODS from Fusarium venenatum NRRL 26139 as a beauvericin synthetase, which was named as FvBEAS. Our work thus provides a useful approach for functional reconstitution and engineering of fungal CODSs for efficient production of this family of anticancer molecules. 相似文献
19.
Guanghai Yu Xiaoqiang Jia Jianping Wen Guoying Wang Yunlin Chen 《World journal of microbiology & biotechnology》2011,27(8):1859-1868
The effects of eight cofactors of enzymes on daptomycin production were investigated in this work, which included nicotinic
acid (VPP), riboflavin (VB2), heme, thiamine (VB1), biotin (VH), cyanocobalamin (VB12), tetrahydrofolic acid (THF) and pyridoxal 5-phosphate (VB6). The dry cell weight (DCW), consumption of glucose, and daptomycin production were obviously improved when proper amount
of exogenous cofactors were supplemented in the medium. The effects of heme, THF, VB12 and VB6 on daptomycin production were especially notable. The daptomycin yield enhanced 363, 104, 53 and 46%, respectively, when
optimized amount of these four cofactors were supplemented in the broth. Moreover, the daptomycin yield further increased
to 632 mg/l, which was over 4.5-fold higher than that of the control (without cofactors), at 132 h in a 7.5-l fermenter, by
supplementation all of the eight cofactors at optimized concentrations (VPP 4 mg/l, VB2 0.5 mg/l, heme 9 mg/l, VB1 0.4 mg/l, VH 0.1 mg/l, VB12 0.04 mg/l, THF 6 mg/l and VB6 0.4 mg/l). Further, the effects of cofactors on the corresponding key enzymes and important intracellular metabolites were
studied in order to elucidate the mechanism of enhancement of daptomycin production by manipulation of cofactors concentration
in the fermentation culture. It is suggested that this strategy for increasing the daptomycin production in Streptomyces roseosporus LC-51 by manipulation of cofactors concentration in the fermentation culture may provide an alternative approach to enhance
the production of metabolites in other Streptomyces. 相似文献
20.
Zoccarato F Miotto C Cavallini L Alexandre A 《Journal of bioenergetics and biomembranes》2011,43(4):359-366
In brain mitochondria succinate activates H2O2 release, concentration dependently (starting at 15 μM), and in the presence of NAD dependent substrates (glutamate, pyruvate,
β-hydroxybutyrate). We report that TCA cycle metabolites (citrate, isocitrate, α-ketoglutarate, fumarate, malate) individually
and quickly inhibit H2O2 release. When they are present together at physiological concentration (0.2, 0.01, 0.15, 0.12, 0.2 mM respectively) they
decrease H2O2 production by over 60% at 0.1–0.2 mM succinate. The degree of inhibition depends on the concentration of each metabolite.
Acetoacetate is a strong inhibitor of H2O2 release, starting at 10 μM and acting quickly. It potentiates the inhibition induced by TCA cycle metabolites. The action
of acetoacetate is partially removed by β-hydroxybutyrate. Removal is minimal at 0.1 mM acetoacetate, and is higher at 0.5 mM
acetoacetate. We conclude that several inhibitors of H2O2 release act jointly and concentration dependently to rapidly set the required level of H2O2 generation at each succinate concentration. 相似文献