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1.
A spin probe method was used to study microviscosity of aqueous medium in embryos and endosperm of maize (Zea mays L.) seeds after their irradiation with a Lvov-1 Elektronika laser device. Based on parameters of electron spin resonance (ESR) spectra of nitroxyl radicals (probes) absorbed by imbibing seeds during water uptake, correlation times τC were determined for the rotational diffusion of probes in embryos and endosperm of seeds. The τC values were found smaller in embryos of irradiated seeds than in untreated seeds; the dependence of τC on the duration of seed imbibition was determined. It is concluded that laser irradiation of seeds decreases the microviscosity of aqueous medium in embryo cells and elevates the mobility of the probes. Effect of laser irradiation on τC in seed endosperm was less pronounced but also led to the increase in probe mobility. 相似文献
2.
Summary Ethylene stimulated growth of rice coleoptiles in the dark and after an irradiation with red light. The red-light inhibition of rice-coleoptile growth was more pronounced when only endogenously evolved C2H4 was involved than it was under C2H4-free (C2H4 removed) or C2H4-saturated (20 ppm C2H4 added) conditions. 相似文献
3.
Light or ethylene treatments induce transverse cell enlargement in etiolated maize mesocotyls 总被引:3,自引:2,他引:1
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Dark-grown maize seedlings (hybrid WF-9 × 38-11) exposed for 1 or more hours to white light and then returned to darkness developed mesocotyls with enlarged apical diameters. This swelling response was an all-or-none response, and the fraction of the seedling population that showed the response depended on seedling age at irradiation. Irradiation of the coleoptile alone was nearly as effective in causing this response as was irradiation of the nodal region of the epicotyl, but irradiation of the mesocotyl base was ineffective. Removal of the coleoptile prior to irradiation did not prevent the formation of the light-induced swelling. Exogenously applied C2H4 (10 microliters per liter) for 24 hours in dark also induced swelling of the mesocotyl. The swelling induced in the intact seedlings was localized in the apical mesocotyl tissues with either light or C2H4 treatment, and maximal response to both treatments occurred with 3- to 4-day-old seedlings. Swelling of the mesocotyl was the result of transverse cell enlargement, not increase of cell numbers. The evidence suggests that light and C2H4 induce mesocotyl swelling in intact maize shoots by a common mechanism. 相似文献
4.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1991,98(1-2):99-101
- 1.1. In eels captured in Roskilde Fjord in 1972 and 1975, a specifically enhanced synthesis was found from 14C-acetate of 14C-labelled mono-unsaturated fatty acids (C16:1 and C18:1) relative to saturated fatty acids (C16:0 and C18:0) in sea water 4 days after irradiation (10 Gy, 60Co).
- 2.2. Corresponding experiments in 1976 and 1982 showed rather the opposite: irradiation resulted in more 14C-labelled saturated fatty acids relative to unsaturated fatty acids, both in fresh and sea water.
- 3.3. The latter effect was less marked than that in 1972 and 1975, but still statistically clearly significant.
5.
The Suzuki-Miyaura reaction of various aryl halides using [Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4} (μ-Br)]2 have been investigated. This orthopalladated complex is an efficient, stable and non-sensitive to air and moisture catalyst for the hetrocoupling reaction in DMF as the reaction solvent at 130 °C. The combination of dimeric complex as homogenous catalyst and microwave irradiation can be very useful and efficient methods in organic synthesis, so the application of microwave irradiation have been investigated using homogenous dimeric complex [Pd{C6H2(CH2CH2NH2)-(OMe)2,3,4} (μ-Br)]2. Application of dimeric complex as catalyst caused to produce the desired coupling products and the using of microwave irradiation improving the yields of the reactions and shortening the reaction times. 相似文献
6.
《生物化学与生物物理学报:生物膜》2018,1860(8):1528-1536
Fullerenols (polyhydroxylated fullerene C60) are nanomaterial with potentially broad applicability in biomedical sciences with high antioxidant ability, thus, we investigated the radioprotecting potential of fullerenol C60(OH)36 on human erythrocytes irradiated by high-energy electrons of 6 MeV. The results demonstrate that C60(OH)36 at concentration of 150 μg/mL protects the erythrocytes against the radiation-induced hemolysis (comparing to non-protected cells, we observed 30% and 39% protection for 0.65 and 1.3 kGy irradiation doses, respectively). The protecting effect was confirmed by 32% decreased release of potassium cations comparing to the cells irradiated without C60(OH)36. Measurements of the amount of lactate dehydrogenase (LDH) released from the irradiated erythrocytes showed that the size of the pores formed by irradiation was not sufficient to release LDH across the erythrocyte membranes. We also report a significant decrease of the affinity of acetylcholinesterase (AChE) for the substrate in the presence of fullerenol, indicating the relatively strong adsorption of C60(OH)36 to components of plasma membrane. Changes in membrane fluidity detected by fluorescence spectroscopy and conformational changes in membrane proteins detected by spin labeling suggest the dose-dependent formation of disulfide groups as an effect of oxidation and this process was inhibited by C60(OH)36. We suppose that scavenging the ROS as well as adsorption of fullerenol to membrane proteins and steric protection of -SH groups against oxidation are responsible for the observed effects. 相似文献
7.
E. M. Eropkina E. V. Ilyinskaya E. V. Litasova M. Yu. Eropkin L. B. Piotrovsky M. A. Dumpis O. I. Kiselev 《Biophysics》2012,57(3):343-349
In view of contradictory data on the toxicity of fullerenes for living organisms we studied the effect of water-soluble complexes of C60 with N-polyvinylpyrrolidone (C60/PVP) and γ-cyclodextrin (C60/γ-CD) on MA-104 cells in culture. Both complexes proved to be nontoxic for cultured cells in the dark in a wide range of concentrations. Both complexes provoke changes of cell ultrastructure that reflect enhancement of metabolic activity. At the same time only the exposition with C60/PVP leads to substantial growth of the number and size of mitochondria. However, the effect of two studied water-soluble forms of C60 under intense UV irradiation of cells proved to be opposite: C60/PVP had a cytoprotective action while C60/γ-CD caused a significant growth of phototoxicity. Possible reasons of the differences in the action of different forms of C60 on living organisms are discussed. 相似文献
8.
Franco Cataldo 《Chemistry and physics of lipids》2010,163(6):524-529
Unsaturated lipids when exposed to air at room temperature undergo a slow autoxidation. When fullerene C60 was dissolved in selected lipids (ethyl oleate, ethyl linoleate, linseed oil and castor oil) the spectrophotometric analysis shows that the oxidation is concentrated to C60 which is converted to an epoxide C60O. Thus, fullerene C60 displays antioxidant activity not only when dissolved in unsaturated lipids but also, more generally, when dissolved in unsaturated solvents subjected to autoxidation like, for example, in cyclohexene. The behaviour of C60 in ethyl oleate has been compared with that of the known antioxidant TMPPD (N,N′,N,N,′-tetramethyl-p-phenylenediamine) in ethyl oleate. The mechanism of the antioxidant action of C60 in lipids has been proposed. The kinetics of C60 oxidation in lipids was determined spectrophotometrically both at room temperature in the dark and under UV irradiation. The oxidized products derived from C60 photo-oxidation in lipids have been identified. 相似文献
9.
Ryoko Asada Feng Liao Yasukazu Saitoh Nobuhiko Miwa 《Molecular and cellular biochemistry》2014,390(1-2):175-184
A water-soluble complex of fullerene [C60]:polyethylene glycol (PEG) (1:350 wt/wt) (C60–PEG), but not PEG alone, was found in the present study by ESR/DMPO spin-trap method to generate hydroxyl radicals 6.5-fold as abundant as the non-irradiation level, when irradiated with visible light (400–600 nm, 140 J/cm2: 450-fold as intense as in average outdoor), but not to generate without irradiation. At 3 h after irradiation with C60–PEG, human fibrosarcoma cells HT1080 were obviously degenerated together with diminished microvilli, cell shrinkage and cell fragmentation as observed by SEM and were shown either for increased cytotoxicity by dual stains with calcein-AM and propidium iodide or for nuclear condensation and fragmentation by Hoechst 33342 stain, any of which were, in contrast, scarcely changed in normal human fibroblastic cells DUMS16 derived from the same connective tissue type as HT1080 cells. Under the conditions, the maximum intracellular uptake amount was more abundant for HT1080 cells than for DUMS16 cells, either by immunostain/fluorography using polyclonal antibody against fullerene [C60], or by HPLC method indicating the 2.4-fold preferential uptake of C60–PEG into HT1080 cells, suggested to greater phagocytotic ability characteristic of cancer cells, over DUMS16 cells being non-macrophage-like normal cells. Thus, C60–PEG is expected as a photosensitizer for photodynamic therapy with scarce side effects to normal cells and preferential reactive oxygen species generation in cancer cells. 相似文献
10.
Stepanenko I. Yu. Strakhovskaya M. G. Belenikina N. S. Nikolaev Yu. A. Mulyukin A. L. Kozlova A. N. Revina A. A. El'-Registan G. I. 《Microbiology》2004,73(2):163-169
The effects of C7-alkylhydroxybenzene (7-AHB) and p-hydroxyethylphenol (tyrosol), chemical analogs of microbial anabiosis autoregulators, on the viability of yeast cells under oxidative stress were investigated. The stress was caused by reactive oxygen species (ROS) produced under irradiation of cell suspensions using doses of 10–150 krad at an intensity of 194 rad/s or by singlet oxygen generated in cells photosensitized with chlorin e
6 (10 g/l). C7-AHB was found to exert a protective effect. The addition of 0.05–0.16 vol % of C7-AHB to cell suspensions 30 min before irradiation protected yeast cells from radiation (50 krad). The protective effect of C7-AHB manifested itself both in the preservation of cell viability during irradiation and in the recovery of their capacity to proliferate after irradiation. In our studies on photodynamic cell inactivation, the fact that the phenolic antioxidant C7-AHB protects cells from intracellular singlet oxygen was revealed for the first time. The analysis of difference absorption spectra of oxidized derivatives of C7-AHB demonstrated that the protective mechanism of 7-AHB involves the scavenging of ROS resulting from oxidative stress. The fact that tyrosol failed to perform a photoprotective function suggests that the antioxidant properties of microbial 7-AHB are not related to its chaperon functions. The results obtained make an important addition to the spectrum of known antioxidant and antistress effects of phenolic compounds. 相似文献
11.
Grigory V. Andrievsky Vadim I. Bruskov Artem A. Tykhomyrov Sergey V. Gudkov 《Free radical biology & medicine》2009,47(6):786-793
Aqueous solutions of highly stable supramolecular donor–acceptor complexes of chemically nonmodified pristine C60 fullerene molecules with H2O molecules (hydrated C60 fullerene–C60HyFn) and their labile nano-sized clusters were examined for their antioxidant effects on removal of hydroxyl radicals (OH) and protecting DNA against oxidative damage induced by ionizing radiation in vitro. The suppressing influence of C60HyFn on the formation of OH-radicals in water exposed to X-rays at doses of 1–7 Gy was assessed by determination of oxidation levels of coumarin-3-carboxylic acid. C60HyFn demonstrates apparent antiradical activity in vitro in the range of concentrations of 10−11–10−6 M. Paradoxically, the OH-removing efficacy of C60HyFn was in reverse correlation with fullerene concentration. It was hypothesized that the antiradical action of C60HyFn in water medium generally is due to a “nonstoichiometric” mechanism, supposedly to a hydrated free radical recombination (self-neutralization), which is catalyzed by specific water structures ordered by C60HyFn. With the use of 8-oxoguanine as a marker of oxidative damage to DNA, it has been demonstrated that C60HyFn in concentrations of 10−7–10−6 M protects nucleic acids against radical-induced damage. The second part of the present study was aimed to evaluate the overall radioprotective efficacy of C60HyFn in doses of 0.1 or 1 mg/kg b.w. injected intraperitoneally to mice either 1 h before or 15 min after lethal dose exposure of the X-ray (7 Gy) irradiation. Survival rate of the mice was observed at 30 day intervals after irradiation, while the weight gains of experimental animals were monitored as well. The most significant protective effect was demonstrated when 1 mg/kg dosage of C60HyFn was administered before irradiation. The outcome of the substance testing is 15% survival rate of irradiated animals at 30 days of observation, and prevention of noticeable weight loss characteristic for radiation impact, versus unprotected control animals. In conclusion, results of the study obviate that the apparent protective action of C60HyFn in vivo is determined by its considerable ability to decrease X-ray-generated reactive oxygen species. Based on the results and that neat C60 is nontoxic, actually in the hydrated form, without side effects and with sufficient radioprotective effects in low doses, C60HyFn may be considered as a novel antioxidant agent, which substantially diminishes the harmful effects of ionizing radiation. 相似文献
12.
γ-Isomer of 1,2,3,4,5,6-hexachlorocyclohexane (BHC) showed greater decomposition on γ or UV irradiation of five isomers of BHC in crystalline state or in 2-propanol solution. The α- and δ-isomer of BHC and known la, 2a, 3e, 4e, 5e-pentachlorocyclohexane were separated from the irradiation product of crystalline γ-BHC. Four compounds were isolated from the irradiation product of γ-BHC in 2-propanol. Two compounds were tetrachloro-cyclohexenes (C6H6C14): γ-isomer (mp 86 ~87°C) and ?-isomer (mp 99 ~ 100°C). The other two were isomers of pentachlorocyclohexane (C6H7C15). One of them (mp 78 ~ 8.5°C) was consistent with known meso-1e,2a,3a,4a,5e isomer. The molecular structure of the other (mp 75°C) established by X-ray crystal structure analysis was 1α, 2α, 3α, 4β, 5α configuration or le 2a 3e 4e 5e conformation of CI atoms. A reaction mechanism was proposed that included a radical chain reaction and chlorine atom migration. 相似文献
13.
The concentration of carbon suboxide (C3O2) in the plasmas of sealed-off discharges in mixtures of CO with noble gases is measured for the first time by mass-spectroscopic technique. It is shown that the production of C3O2 (and, possibly, more complex carbon oxides) in a gas-discharge plasma significantly boosts the vibrational relaxation of CO molecules and thus greatly affects their vibrational populations. Adding xenon to a He: CO mixture reduces the concentration of C3O2. The effect of pulsed UV radiation on the vibrational populations of CO molecules is studied experimentally. It is shown that UV irradiation of the gas mixture after long-term discharge operation increases vibrational populations in the plateau region up to the values observed at the beginning of the discharge. This effect is attributed to the decay of C3O2 molecules under the action of UV radiation. 相似文献
14.
Gamma radiation at doses of 300 Krad or more inhibits the ripening of Bartlett pears (Pyrus communis L.). Immediately after irradiation there is a transitory burst of C2H4, which subsequently declines in fruits subjected to inhibitory doses. Ethylene production associated with ripening begins at the same time in unirradiated fruits and those subjected to noninhibitory doses, but the latter produces much more C2H4 at the climacteric peak. Fruits subjected to inhibitory doses produce low levels of C2H4 unless subjected to exogenously applied C2H4, whereupon they produce enough of the gas to induce ripening in unirradiated fruits.
Pears subjected to 300 and 400 Krad of gamma rays did not ripen even when held in a flowing atmosphere containing 1000 ppm of C2H4 for 8 days at 20°. It is concluded that the action of gamma rays on Bartlett pears involves both an inhibition of C2H4 production and a decreased sensitivity of the fruit to the ripening action of the gas. Ripening of Bartlett pears is inhibited by gamma radiation only when applied to preclimacteric fruit.
相似文献15.
Natural occurrence of C4 species, life forms, and their longitudinal distribution patterns along the Northeast China Transect (NECT) were studied. Six vegetation regions experiencing similar irradiation regimes, but differing in longitude, precipitation, and altitude were selected along the NECT from 108 to 131 °E, around altitude of 43.5 °N. Seventy C4 species were identified in 41 genera and 13 families. 84 % of the total C4 species were found in four families: Gramineae (38 species), Chenopodiaceae (11 species), Cyperaceae (5 species), and Amaranthaceae (5 species). C4 grasses make up 54 % of the total identified C4 species along the NECT and form the leading C4 family in meadow, steppe, and desert along the NECT. C4
Chenopodiaceae species make up about 16 % of the C4 species and become less important, particularly in the meadow and the eastern end of the NECT. 57 % of the total C4 species are therophytes and 37 % are hemicryptophytes, which is consistent with floristic composition and land utilization. In general, the number of C4 species decreased significantly from the west to the east or from dry to moist areas along the NECT, and was remarkably correlated with annual precipitation (r
2= 0.677) and aridity (r
2= 0.912), except for salinized meadow region. The proportion of C4 species from all the six vegetation regions was considerably correlated with these two climatic parameters (r
2= 0.626 or 0.706, respectively). These findings suggest that the natural occurrence of C4 species varies significantly along the large-scale longitudinal gradient of the NECT. The notable relationship of C4 species number and proportion in the flora with variations in annual precipitation and aridity suggest that these two climatic parameters are the main factors controlling the longitudinal distribution patterns of C4 species along the NECT. 相似文献
16.
Ferit Kocacinar 《Physiologia plantarum》2015,153(3):454-466
In plants, most water is absorbed by roots and transported through vascular conduits of xylem which evaporate from leaves during photosynthesis. As photosynthesis and transport processes are interconnected, it was hypothesized that any variation in water transport demand influencing water use efficiency (WUE), such as the evolution of C4 photosynthesis, should affect xylem structure and function. Several studies have provided evidence for this hypothesis, but none has comprehensively compared photosynthetic, hydraulic and biomass allocation properties between C3 and C4 species. In this study, photosynthetic, hydraulic and biomass properties in a closely related C3 Tarenaya hassleriana and a C4 Cleome gynandra are compared. Light response curves, measured at 30°C, showed that the C4 C. gynandra had almost twice greater net assimilation rates than the C3 T. hassleriana under each increasing irradiation level. On the contrary, transpiration rates and stomatal conductance were around twice as high in the C3, leading to approximately 3.5 times higher WUE in the C4 compared with the C3 species. The C3 showed about 3.3 times higher hydraulic conductivity, 4.3 times greater specific conductivity and 2.6 times higher leaf‐specific conductivity than the C4 species. The C3 produced more vessels per xylem area and larger vessels. All of these differences resulted in different biomass properties, where the C4 produced more biomass in general and had less root to shoot ratio than the C3 species. These results are in support of our previous findings that WUE, and any changes that affect WUE, contribute to xylem evolution in plants. 相似文献
17.
Nitrous Acid Reactivation of Ultraviolet-Irradiated Transforming DNA from Hemophilus influenzae
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Emiliano Cabrera-Jurez 《The Journal of general physiology》1963,47(2):279-296
Partial recovery of ultraviolet-damaged denatured or native transforming DNA from Hemophilus influenzae, has been obtained by exposing the irradiated DNA in the denatured form to nitrous acid. Some factors that affect this recovery are described. An erythromycin marker (E20) was not reactivated. The UV damage reactivable by nitrous acid is different from that repaired by the photoreactivating enzyme from bakers' yeast. The pretreatment with nitrous acid affords a slight protection for denatured C25 DNA and Sm250 DNA against ultraviolet irradiation, but this pretreatment sensitized the E20 DNA to this irradiation. 相似文献
18.
The fraction of murine epididymal sperm with shape abnormalities ranged from 1.0–15.0% in 14 inbred strains and hybrids studied. The effect of x-rays on this fraction was examined in mice with markedly different natural levels of abnormalities, C57BL (9.4%) and (C57BL×C3H)F1 (1.0%). Dosages of 30, 100, and 300 rad produced a significant increase in the number of abnormal forms, especially from 3–8 weeks following irradiation. The fraction of abnormal sperm at 5 weeks following graded doses of radiation from 0–300 rad increased from control values to 30%. The data for the hybrid fitted curve which increased as the power of the dose and which gave a doubling in abnormalities compared with control at rad. Sperm abnormalities may permit a simple quantitative assay for damage to the genetic material of the male germ line. 相似文献
19.
One species of hydrocarbon utilizing bacteria was isolated from soil. This strain was named as Achromobacter petrophilum No. 4017. This bacterial species utilizes normal hydrocarbons with carbon chains of nC10 to nC18, but does not utilize glucose or other carbohydrates. Achromobacter petrophilum forms small amounts of green-yellow, green-blue and violet fluorescent compounds in the medium containing n-hexadecane (nC16) as a carbon source. The mutant strain, No. 4510, which requires hypoxanthine and thiamine for growth, was obtained from Achromobacter petrophilum No. 4017 by ultraviolet irradiation and formed considerable amounts of green-yellow fluorescent compound by the addition of guanine to the n-hexadecane medium. This fluorescent compound was crystallized from culture broth. 相似文献
20.
6-Azido-5-decyl-2,3-dimethoxy-p-benzoquinone (6-azido-Q0C10) was found to replace the native plastoquinone at B (the second stable electron acceptor to Photosystem II (PS II)). The 6-azido-Q10C10 would accept electrons from the primary electron-accepting quinone, Q, thus allowing electron transport through PS II to the plastoquinone pool in thylakoids. The synthetic azidoquinone also competes with the PS II herbicides ioxynil and atrazine for binding. This observation strongly favors the hypothesis that PS II herbicides block electron transport by replacing the native quinone which acts as the second electron carrier on the reducing side of PS II (termed B). Covalent linkage of 6-azido-Q0C10 to its binding environment by ultraviolet irradiation greatly reduces herbicide-binding affinity but does not lead to a loss in herbicide-binding sites. We take this as evidence that covalent attachment of 6-azido-Q0C10 allows some freedom of quinone head-group movement such that the herbicides can enter the binding site. This indicates that the protein determinants which regulate quinone and herbicide binding are very closely related, but not identical. A compound somewhat related to 6-azido-Q0C10 is 2-azido-3-methoxy-5-geranyl-6-methyl-p-benzoquinone (2-azido-Q2). This compound was found to be an ineffective competitor with respect to herbicide binding. Thus, interactions with protein-binding determinants are highly dependent on the molecular structure of quinones. The 2-azido-Q2 was an inhibitor of electron flow in the intersystem portion of the chain. 相似文献