共查询到20条相似文献,搜索用时 31 毫秒
1.
M. J. Ruwart N. M. Nichols K. Hedeen B. D. Rush J. Stachura 《In vitro cellular & developmental biology. Plant》1985,21(8):450-452
Summary 16,16-Dimethyl PGE2 (dmPGE2) has previously been shown to protect the in vivo rat liver against CCl4-induced damage. These studies were undertaken to determine if this protection could be demonstrated in vitro where factors
of absorption, secretion, and blood flow are not present. Primary hepatocyte cultures were established by perfusing rat liver
with collagenase. Hepatocytes were plated at a density of 2×104 cells/cm, allowed 90 min to attach, then stabilized in L15 medium for 18 h. Hepatocytes were then challenged with CCl4 with concomitant exposure to 10−9 to 10−5
M dmPGE2, stearic acid, oleic acid, or ethanol vehicle (0.00001 to 0.1%). After 1 h, challenge was aspirated and cells were stained
with 0.04% trypan blue to determine viability. Hepatocytes in the vehicle groups took up more trypan when exposed to CCl4 than those treated with dmPGE2, stearic acid, or oleic acid at concentrations of 10−9 to 10−7
M. At 0.1% ethanol vehicle protected as well as all other treatments. Protection against CCl4 by dmPGE2, stearic, and oleic acids as well as high concentrations of ethanol may occur by altering the metabolism of CCl4. 相似文献
2.
Mervi T. Hyvönen Riitta Sinervirta Nikolay Grigorenko Alex R. Khomutov Jouko Vepsäläinen Tuomo A. Keinänen Leena Alhonen 《Amino acids》2010,38(2):575-581
The role of polyamines in carbon tetrachloride (CCl4)-induced organ injury was studied in syngenic rats and transgenic rats with activated polyamine catabolism. In syngenic rats,
administration of CCl4 resulted in the induction of hepatic spermidine/spermine N
1-acetyltransferase (SSAT), accumulation of putrescine, reduction in spermine level and appearance of moderate hepatic injury
within 24 h. Upon treatment with CCl4, transgenic rats overexpressing SSAT displayed induction of both hepatic and pancreatic SSAT, with subsequent accumulation
of putrescine and decrease of both spermidine and spermine pools. Administration of CCl4 in SSAT transgenic rats induced not only massive hepatic injury, but also severe acute necrotizing pancreatitis. Pretreatment
of the animals with catabolically stable functional polyamine mimetic, α-methylspermidine (MeSpd) prevented pancreatic and
hepatic injury in SSAT rats and markedly reduced liver damage in syngenic animals. As assessed by immunostaining of proliferating
cell nuclear antigen, MeSpd increased the amount of regenerating hepatocytes in both genotypes. These results show that CCl4 induces hepatic and pancreatic polyamine catabolism, and the extent of organ damage correlates with the degree of polyamine
depletion. Furthermore, MeSpd protects against CCl4-induced hepatic and pancreatic damage and promotes tissue regeneration. 相似文献
3.
Exposure of isolated rat hepatocytes to hepatotoxic halomethanes results in a 40–60% decrease in intracellular Ca2+ content. The order of halomethane potency (CBrCl3 CCl4 CHCl3) suggests that this effect requires halomethane metabolism by the hepatic mixed function oxidase system. Although the Ca2+ sequestering ability of the endoplasmic reticulum is destroyed by CBrCl3 and CCl4, it appears that much of the Ca2+ lost from the cell is mitochondrial in origin. Paradoxically, saturating concentrations of CCl4 cause a marked increase in cell Ca2+. CCl4 also causes an acute increase in cytoplasmic free Ca2+ (from about 60 nM to about 90 nM), but this effect does not appear to require CCl4 metabolism and is probably a result of direct action of CCl4 on the plasma membrane. 相似文献
4.
Mi-Ran KiHye-Rim Lee Jin-Kyu ParkIl-Hwa Hong Seon-Young HanSang-Young You Eun-Mi LeeAh-Young Kim Seung-Sook LeeKyu-Shik Jeong 《The Journal of nutritional biochemistry》2011,22(6):535-542
The genetic deletion of the senescence marker protein 30 (SMP30) gene results in ascorbate deficiency and the premature aging processes in mice. Apparent liver injury of SMP30−/− mice was less severe than those of wild type (WT) mice, upon chronic CCl4 injection. The purpose of this study was to investigate the pathophysiology underlying the mild CCl4 toxicity in SMP30−/− mice. Along with the lower level of serum alanine aminotransferase, the livers of SMP30−/− mice revealed a lesser glycogen depletion, a decrease in c-Jun N-terminal kinase (JNK)-mediated inflammatory signaling in parallel with tumor necrosis factor-alpha and interleukin-1 beta, inducible nitric oxide synthase and glutathione peroxidase, and the lower lipid peroxidation as compared to those of WT mice. CCl4-induced proliferation, measured by the expression of proliferating cell nuclear antigen, was low in SMP30−/− mice as compared with that of WT mice whereas the levels of p21 and Bax were comparable to those of the CCl4-treated WT mice. Moreover, CCl4 toxicity in ascorbate-fed SMP30−/− mice was comparable to that of the CCl4-alone treated WT mice, accompanied by an increase in the above mentioned factors. Conversely, ascorbate partly compensated for the CCl4-induced oxidative stress in WT mice, indicating that sufficient ascorbate may be required for an antioxidant function under severe levels of oxidative stress. Our data suggest that the restoration of ascorbate-deficiency reverses a sluggish immune system into an activated condition by an increase in JNK-mediated inflammation and free radical cascade; thus leading to accelerated hepatic damage in SMP30−/− mice. 相似文献
5.
We examined the effects of isopropanol (ISOP) pretreatment on the metabolism of 14CCl4 to 14CO2 and CHCl3 exhaled in the breath, to 14C metabolite excreted in 24 hr urine and feces from 0 to 24 hr, and to 14C metabolite bound to liver at 24 hr. Fasted male rats were given 0.1 or 2.0 mmoles 14CCl4/kg. ISOP pretreatment, which markedly enhanced the hepatotoxicity of CCl4, selectively enhanced the rate and total extent of 14CO2 and CHCl3 metabolite exhalation. The pathways of CCl4 metabolism leading to CO2 and CHCl3 metabolite formation may be more relevant to the hepatotoxicity of CCl4 than the pathways leading to urinarym fecal or covalently bound metabolites. 相似文献
6.
M. Marinovich L.M. Flaminio M. Papagni C.L. Galli 《Prostaglandins & other lipid mediators》1989,37(1)
Arachidonic acid metabolism was evaluated in isolated rat hepatocytes after CCl4 exposure. CCl4 induced dose-dependently the synthesis and release of prostacyclin (PGI2) and thromboxane (TXB2). Treatment with prostaglandin E2 (PGE2) 30 min after exposure to CCl4, significantly reduced the cell damage as well as the release of TXB2 from the cells. 相似文献
7.
Thomas C.W. Mak 《Inorganica chimica acta》1985,109(2):131-133
The title compound has been synthesized and subjected to crystal structure analysis. Mr = 548.50, m.p. 108.1 °C (decom.), orthorhombic, Im2m,a = 7.006(2), b = 8.938(2), c = 13.619(2) Å V = 852.8(3) Å3, Z = 2, Dx = 2.136, Dm, (flotation in CCl4/CH2I2) = 2.128 g cm?3, λ(Mo-Kα) = 0.71069 Å, μ = 90.79 cm?1, F(000) = 519.89, T = 295 K, final RF = 0.036 and RG = 0.044 for 566 observed reflections. The discrete [UO2F4(H20)]2? anion has site symmetry m2m, its virtually linear uranyl moiety being surrounded by fluoro and aquo ligands occupying the vertices of a pentagon in the equatorial plane. Watet molecules serve to link the complex anions by hydrogen bonds into layers, between which the organic cations are accommodated. 相似文献
8.
《Free radical research》2013,47(6):359-369
Spin trapping techniques have been used to detect free radicals generated from the in vitro metabolism by rat liver microsomes of carbon tetrachloride (CCl4) and bromotrichloromethane (BrCCI) under conditions of varying oxygen tension and pH. Dispersions of rat liver microsomes incubated with 12CCl4, 13CCl4 or Br12CCl3, α-phenyl-tert-butyl nitrone (PBN) and NADPH/NADH in a phosphate buffer varying in pH from 6.6 to 8.0 under varying oxygen tensions produced various amounts of four different PBN adducts: PBN-CCl3, PBN-L, PBN-OL and PBN-CO?2 where L is a carbon-centered lipid type radical and LO is an oxygen-centered lipid type radical. The relative amount of PEN-CO; increases with the absence of oxygen. With the use of 31P-NMR in vivo spectroscopy it was possible to detect a pH change from 7.4 to 6.8 in the livers of rats treated with CCl4, or BrCCl3. These results suggest that halocarbon metabolism in biological systems may depend on both oxygen tension as well as pH. 相似文献
9.
Yu-Ping Hsieh Chih-Lung Lin An-Li Shiue Huiyong Yin Jason D. Morrow Jee-Ching Hsu Tsung-Che Hsieh Hsing-Ju Wei Hsiu-Chuan Yen 《Free radical biology & medicine》2009,47(6):814-824
Aneurysmal subarachnoid hemorrhage (aSAH) is one type of hemorrhagic stroke in humans. F2-isoprostanes (F2-IsoPs) and F4-neuroprostanes (F4-NPs), derived from arachidonic acid and docosahexaenoic acid (DHA), respectively, are specific markers of lipid peroxidation. We previously demonstrated that F2-IsoPs levels in cerebrospinal fluid (CSF) of aSAH patients positively correlated with poor clinical conditions. In this work, we refined F4-NPs analysis and investigated the role of potential oxidative damage to neurons in aSAH patients by detecting F4-NPs in CSF. [2H4]-15-F2t-IsoP, rather than [18O2]-17-F4c-NP or [2H4]-PGF2α, was used as the internal standard for F4-NPs analysis. One problem of the use of [18O2]-17-F4c-NP was the potential interference resulting from F2-dihomo-IsoPs in CSF. CSF specimens of 15 aSAH patients for up to 10 days and those of 12 non-aSAH controls were analyzed. First day, mean, and peak levels of F4-NPs were all significantly higher in aSAH patients than in controls and correlated with the Fisher Scale and 3-month Glasgow Outcome Scale, but only mean levels of F4-NPs correlated with Hunt and Hess Grade. The results first demonstrate oxidative damage to DHA in brain tissue following aSAH and suggest that F4-NPs in CSF could be a better predictor for outcome of aSAH than F2-IsoPs at early time points. 相似文献
10.
A. C. Meneguelli-Souza A. P. Vitória T. O. Vieira M. S. O. Degli-Esposti C. M. M. Souza 《Photosynthetica》2016,54(2):243-250
Arsenic is a critical contaminant that is released into the environment through geochemical processes and anthropic actions. Two independent hydroponic experiments were performed to evaluate the ecophysiological responses of water hyacinth [Eichhornia crassipes (Mart.) Solms] to As under various stress conditions. In experiment 1, water hyacinth was exposed to As5+ at concentrations of 0, 0.2, 2.0, and 20 mg L?1 for 0, 2, and 4 d; in experiment 2, water hyacinth was exposed at concentrations of 0, 0.025, 0.05, and 0.1 mg L?1 for 0, 10, and 20 d. In both experiments, As accumulation in plant tissue was proportional to its increase in the nutrient solution; As concentrations were higher in roots than in shoots. Detrimental effects of As on gas exchange were observed and were more pronounced in experiment 1. In experiment 1, at the beginning on the second day of exposure, significant decreases of maximum photochemical efficiency of PSII (Fv/Fm), variable chlorophyll fluorescence (Fv/F0), and photosynthetic pigment contents were observed in plants exposed to 2.0 and 20 mg(As5+) L?1. It indicated that damage to the photosynthetic apparatus had occurred. No changes in Fv/Fm, Fv/F0, and contents of photosynthetic pigments were observed in the plants grown in the presence of 0.2 mg(As5+) L?1 (in experiment 1) or after any of the treatments in experiment 2, indicating plant tolerance. Elevated nonphotochemical quenching was observed in experiment 2 after 20 d of exposure to As; it was as a part of protection mechanisms of the photosynthetic apparatus in these plants. The results obtained here indicate that the use of water hyacinth for As5+ removal from highly impacted environments is limited but that it is effective in remediating sites with a low contamination. 相似文献
11.
This investigation generated rovibrational energies and spectroscopic constants for systems of CCl4 with Ng (Ng?=?He, Ne, Ar), O2, D2O and ND3 from scattering experimental data, and the results presented are of interest for microwave spectroscopy studies of small halogenated molecules. The rovibrational spectra were obtained through two different approaches (Dunham and DVR) within the improved Lennard Jones (ILJ) model. Spectra were also generated within ordinary Lennard Jones and deviations suggest that the ILJ model should be preferred due to interactions beyond dispersion forces presented in these systems. Data from the literature and additional high level quantum mechanical calculations presented in this work show that these systems should not be considered as van der Waals complexes due to halogen bonding (HB) interactions, and this is especially true for the CCl4–D2O and CCl4–ND3 complexes. The charge displacement from the latter systems are one order of magnitude higher than the values from literature for CCl4 and He, Ne, Ar and O2 systems, and show significant deviations between DFT and Hartree-Fock values not previously reported in the literature. 相似文献
12.
The changes in photosynthetic efficiency and photosynthetic pigments during dehydration of the resurrection plantSelaginella lepidophylla (from the Chiuhahuan desert, S.W. Texas, USA) were examined under different light conditions. Changes in the photosynthetic
efficiency were deduced from chlorophyll a fluorescence measurements (Fo, Fm, and Fv) and pigment changes were measured by HPLC analysis. A small decrease in Fv/Fm was seen in hydrated stems in high light (650 μmol photons·m−2·s−1) but not in low light (50 μmol photons·m−2·s−1). However, a pronounced decline in Fv/Fm was observed during dehydration in both light treatments, after one to two hours of dehydration. A rise in Fo was observed only after six to ten hours of dehydration. Concomitant with the decrease in photosynthetic efficiency during
dehydration a rise in the xanthophyll zeaxanthin was observed, even in low-light treatments. The increase in zeaxanthin can
be related to previously observed photoprotective non-photochemical quenching of fluorescence in dehydrating stems ofS. lepidophylla. We hypothesize that under dehydrating conditions even low light levels become excessive and zeaxanthin-related photoprotection
is engaged. We speculate that these processes, as well as stem curling and self shading (Eickmeier et al. 1992), serve to
minimize photoinhibitory damage toS. lepidophylla during the process of dehydration. 相似文献
13.
Priscila R Moreira Marcos A Maioli Hyllana CD Medeiros Marieli Guelfi Flávia TV Pereira Fábio E Mingatto 《Biological research》2014,47(1)
Background
The liver is an important organ for its ability to transform xenobiotics, making the liver tissue a prime target for toxic substances. The carotenoid bixin present in annatto is an antioxidant that can protect cells and tissues against the deleterious effects of free radicals. In this study, we evaluated the protective effect of bixin on liver damage induced by carbon tetrachloride (CCl4) in rats.Results
The animals were divided into four groups with six rats in each group. CCl4 (0.125 mL kg-1 body wt.) was injected intraperitoneally, and bixin (5.0 mg kg-1 body wt.) was given by gavage 7 days before the CCl4 injection. Bixin prevented the liver damage caused by CCl4, as noted by the significant decrease in serum aminotransferases release. Bixin protected the liver against the oxidizing effects of CCl4 by preventing a decrease in glutathione reductase activity and the levels of reduced glutathione and NADPH. The peroxidation of membrane lipids and histopathological damage of the liver was significantly prevented by bixin treatment.Conclusion
Therefore, we can conclude that the protective effect of bixin against hepatotoxicity induced by CCl4 is related to the antioxidant activity of the compound. 相似文献14.
Alexander Bauer Anika Schumann Christian Wilhelm Jürgen Schiller 《Chemistry and physics of lipids》2009,159(1):21-103
Carbon tetrachloride (CCl4) represents an excellent model to study oxidative injury of cells. It is widely accepted that hepatocellular injury is a consequence of the metabolic conversion of CCl4 into highly reactive, free radical intermediates. Among the direct toxic effects of CCl4, stimulation of lipid peroxidation and the binding of the electrophilic radicals to membrane lipids have been suggested to play important roles in the pathogenesis of irreversible cell damage. CCl4-induced liver damage was modeled in cultures of rat hepatocytes with the focus on alterations of phosphatidylcholine (PC). The PC acyl chain composition was analyzed by 31P NMR spectroscopy and MALDI-TOF mass spectrometry. The content of the membrane arachidonoyl PC was decreased by almost 30% after incubation of the cells with CCl4. This relative decrease was found to correlate with increased concentrations of the corresponding saturated lysophosphatidylcholine (LPC). It is concluded that LPC represents a useful biomarker of CCl4-mediated damaging of hepatocytes. It is also speculated that de novo biosynthesis of PC is influenced by CCl4. 相似文献
15.
The structure and stability of endohedral X@C20F20 complexes (X = H−, F−, Cl−, Br−, H, He) have been computed at the B3LYP level of theory. All complexes in I
h symmetry were found to be energy minimum structures. H−@C20F20 and F−@C20F20 complexes have negative inclusion energies, while other complexes have positive inclusion energies. Similarity between C20F20 and C20H20 has been found for X = H and He. On the basis of the computed nucleus independent chemical shift values at the cage center,
both C20F20 and C20F20 are aromatic.
Figure Endohedral X@C20F20 complexes 相似文献
16.
Crocin Abrogates Carbon Tetrachloride‐Induced Renal Toxicity in Rats via Modulation of Metabolizing Enzymes and Diminution of Oxidative Stress,Apoptosis, and Inflammatory Cytokines
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Memy H. Hassan Saleh A. Bahashawan Tamer M. Abdelghany Gamil M. Abd‐Allah Mohamed M. Ghobara 《Journal of biochemical and molecular toxicology》2015,29(7):330-339
This work aimed at investigating the potential modulatory effects and mechanisms of crocin against CCl4‐induced nephrotoxicity. Forty male rats were allocated for three weeks treatment with corn oil, CCl4, crocin, or crocin plus CCl4. Crocin effectively mitigated CCl4‐induced kidney injury as evidenced by amelioration of alterations in kidney histopathology, renal weight/100 g body weight ratio and kidney functions. Crocin modulated CCl4‐induced disturbance of kidney cytochrom‐P450 subfamily 2E1 and glutathione‐S‐transferase. The attenuation of crocin to kidney injury was also associated with suppression of oxidative stress via reduction of lipid peroxides along with induction of renal glutathione content and enhancement of superoxide dismutase, glutathione peroxidase, and catalase activities. Crocin mitigated CCl4‐induced elevation of the renal levels of tumor necrosis factor‐alpha, interleukin‐6, prostaglandin E2, and active caspases‐3. Collectively, crocin alleviated CCl4‐induced renal damage via modulation of kidney metabolizing enzymes, suppression of oxidative stress, inhibition of inflammatory cytokines, PGE2, and active caspase3 in kidney. 相似文献
17.
Fang Zhang Xingtong Wang Xiaochen Qiu Junjie Wang He Fang Zhihong Wang Yu Sun Zhaofan Xia 《PloS one》2014,9(11)
Inflammatory response and oxidative stress are considered to play an important role in the development of acute liver injury induced by carbon tetrachloride (CCl4) and galactosamine (GalN)/lipopolysaccharides (LPS). Esculentoside A (EsA), isolated from the Chinese herb phytolacca esculenta, has the effect of modulating immune response, cell proliferation and apoptosis as well as anti-inflammatory effects. The present study is to evaluate the protective effect of EsA on CCl4 and GalN/LPS-induced acute liver injury. In vitro, CCK-8 assays showed that EsA had no cytotoxicity, while it significantly reduced levels of TNF-α and cell death rate challenged by CCl4. Moreover, EsA treatment up-regulated PPAR-γ expression of LO2 cells and reduced levels of reactive oxygen species (ROS) challenged by CCl4. In vivo, EsA prevented mice from CCl4-induced liver histopathological damage. In addition, levels of AST and ALT were significantly decreased by EsA treatment. Furthermore, the mice treated with EsA had a lower level of TNF-α, Interleukin (IL)-1β and IL-6 in mRNA expression. EsA prevented MDA release and increased GSH-Px activity in liver tissues. Immunohistochemical staining showed that over-expression of F4/80 and CD11b were markedly inhibited by EsA. The western bolt results showed that EsA significantly inhibited CCl4-induced phosphonated IkBalpha (P-IκB) and ERK. Furthermore, EsA treatment also alleviated GalN/LPS-induced acute liver injury on liver enzyme and histopathological damage. Unfortunately, our results exhibited that EsA had no effects on CCl4-induced hepatocyte apoptosis which were showed by TUNEL staining and Bax, Caspase-3 and cleaved Caspase-3 expression. Our results proved that EsA treatment attenuated CCl4 and GalN/LPS-induced acute liver injury in mice and its protective effects might be involved in inhibiting inflammatory response and oxidative stress, but not apoptosis with its underlying mechanism associated with PPAR-γ, NF-κB and ERK signal pathways. 相似文献
18.
Freezing and high temperature thresholds of photosystem 2 (PS2), ice formation and frost and heat damage were measured in leaves of evergreen subalpine plants under conditions of naturally low (winter) to high (summer) PS2 efficiencies (FV/FM). The temperature‐dependent change in basic Chl fluorescence (F0) (T‐F0) technique that is usually used to assess the high temperature threshold of PS2 in a new approach was applied to test freezing temperature thresholds of PS2. T‐F0 curves (+5 °C to ?10 °C at 2 K h?1) revealed a significant, sudden increase in F0 on extracellular ice formation (?4.0 or ?5.5 °C). The rise in F0 was recorded 0.3–0.6 K below ice nucleation (10–20 min later) and was produced by freeze dehydration of cells. The rise in F0 was not caused by frost damage, as during winter LT50 was lower than ?27 °C and not by formation of ice on the leaf surface. Hence, F0 measurements during freezing are a useful tool to distinguish between surface ice and extracellular ice inside the leaf tissue which cannot be differentiated by other ice‐detecting methods. PS2 efficiency significantly affected the shape of the high temperature T‐F0 curves (20–65 °C at 1 K min?1). Under FV/FM >0.6, two F0 maxima were recorded. The fast rise phase to the first F0 maximum corresponded with tissue heat damage (LT50: 46.9–54.3 °C). The second F0 maximum occurred at leaf temperatures between 55 and 60 °C. Under FV/FM <0.2 only, the second F0 maximum was detectable. Lack of awareness of the missing F0 maximum would lead to an overestimation of the PS2 high temperature threshold by >10 K; hence, under low FV/FM, it cannot be determined by the T‐F0 technique. 相似文献
19.
Susanna A. Stromeyer Karin Stumpf Alasdair M. Cook Thomas Leisinger 《Biodegradation》1992,3(1):113-123
The transformations of 14CCl4 by whole cells of Acetobacterium woodii suspended in phosphate buffer containing reducing agents, and by the cobalt corrinoid aquocobalamin in the same solution, were compared. Each catalyst transformed 14CCl4 not only to reduced products (CHCl3 and CH2Cl2) but also to CO and CO2 as well as non-volatile products. The mass balance for radioactive carbon was complete in each case. Thus, the reactions of the pure cobalt corrinoid resemble the reactions in vivo. The proton in CHCl3, formed from CCl4 by A. woodii, was derived from water. Extracts of A. woodii were fractionated into large and small molecules, and each of the two fractions was separated chromatographically. Fractions of proteins demonstrated poor correlation between content of the corrinoid vitamin B12 and rates of transformation of CCl4. The correlation was somewhat improved if the fractions were autoclaved, but dechlorination in the absence of vitamin B12 was observed. Separation of the small molecules yielded only one fraction containing vitamin B12, and this fraction catalyzed dechlorination, whereas several other fractions were able to dechlorinate CCl4 in the absence of vitamin B12. We presume there to be unrecognized dechlorinative factors in anaerobic bacteria.Abbreviations GC
gas chromatograph(y)
- GC-MS (or-TCD or-FID)
GC coupled to a mass spectrometer (or a thermal conductivity detector or a flame ionization detector)
- HPLC
high pressure liquid chromatograph(y)
- FPLC
high pressure protein chromatograph(y) 相似文献
20.
Voronova E. N. Volkova E. V. Kazimirko Yu. V. Chivkunova O. B. Merzlyak M. N. Pogosyan S. I. Rubin A. B. 《Russian Journal of Plant Physiology》2002,49(3):311-319
The response of the photosynthetic apparatus to high irradiance illumination (440–2200 W/m2) was studied in the diatom Thallassiosira weisflogii by fluorescence methods. Changes in the photosynthetic apparatus were monitored by measuring characteristics of chlorophyll fluorescence F
0, F
m, F
v/F
m, and qN for several hours after illumination of the alga with high-intensity light. Incubation of the alga with 2 mM DTT, an inhibitor of de-epoxidase of carotenoids in the diadinoxanthin cycle, led to a decrease in the nonphotochemical quenching of chlorophyll fluorescence and a drop in the F
v/F
m ratio, a characteristic that reflects the quantum efficiency of the functioning of the photosynthetic apparatus. Light-induced absorption changes associated with transformations of carotenoids of diadinoxanthin cycle were recorded in vivo in algal suspensions in the absence and in the presence of DTT. Using the microfluorometric method, we measured cell distribution over the efficiency of the primary processes of photosynthesis (F
v/F
m) after illumination. We found cells with a high tolerance of their photosynthetic apparatus to photooxidative damage. The relatively high tolerance of a portion of the cell population to high-light illumination can be related to light-induced transformation of carotenoids and to the functioning of other protective systems of the photosynthetic apparatus in diatoms. 相似文献