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1.
Luminescent fungi spontaneously emit light during certain stagesof their life cycles. Most of them are luminous during a partof their mycelial stage, but not many of them are luminous whenthey form fruiting bodies. In the case of Panellus stipticus,both the mycelium and the fruiting body can be luminous, andthe emission of light takes place when its luciferin is aerobicallyoxidized in the presence of the superoxide anion (O2) and acationic surfactant. It is highly likely that the luminescencereactions of all kinds of luminous fungi are basically the sameas that of P. stipticus. In order to determine the factor thatmakes a fungus luminous or non-luminous, we studied the relationsbetween the light emission of fungi at various growth stagesand the contents of luciferin, its precursor, superoxide dismutase(SOD), and catalase, on six species of luminescent fungi: Armillariellamellea, Mycena citricolor, Mycena lux-coeli, Omphlotus olearious,Panellus stipticus, and Pleurotus japonicus. The analysis ofthe data suggested that the fungi generally contain the componentsnecessary for light emission, but also contain very large amountsof SOD which destroy O2. If an appreciable amount ofSOD is distributed at the site of light emission, the luminescencereaction is prevented. For the reaction to take place, it isessential that the SOD activity at the site is sufficientlylow or inhibited, despite the high content of SOD in the wholetissue. Thus, the level of SOD activity at the site of lightemission appears to be a limiting factor in regulating the luminescenceof fungi. Key words: Bioluminescence, chemiluminescence, luminous fungi, superoxide ion, superoxide dismutase 相似文献
2.
The chemical structure of two luciferin precursors PS-A and PS-B, isolated from the luminous mushroom Panellus stipticus, were determined as 1-O-decanoylpanal (2) and 1-O-dodecanoylpanal (3), respectively. Both PS-A and PS-B were converted into chemiluminescent luciferins by treatment with 50 mmol/l methylamine in a pH 3.5 buffer solution containing an anionic surfactant Tergitol 4 at 25–35ºC. The luciferins emitted chemiluminescence in a pH 7–8 buffer solution containing a cationic surfactant in the presence of O2 and O. 相似文献
3.
《Luminescence》2003,18(1):31-36
Enhanced chemiluminescence (ECL) describes the phenomenon of increased light output in the luminol oxidation reaction catalysed by horseradish peroxidase (HRP) in the presence of certain compounds, such as para‐iodophenol. In this work, the effects of phenol on the para‐iodophenol‐enhanced HRP‐catalysed chemiluninescent reaction intensity in an aqueous buffer (Tris–HCl buffer, pH 8.5) and in a surfactant–water–octane mixture were compared. Preincubation of HRP at low phenol concentrations stimulated the chemiluminescent intensity in the assay performed in an aqueous buffer, but did not have significant effect in the sodium bis(2‐ethylhexyl)sulphosuccinate) (Aerosol OT, AOT) applied system. It was also observed that HRP preincubation with phenol concentration higher than 0.003 mg/mL produced an inhibitory effect on the enzyme activity for both assay systems. Only an inhibitory effect of phenol on the chemiluminescent intensity in the surfactant system in octane (as organic solvent) was observed. Three assays were developed to determine phenol concentration in water and in an organic solvent mixture. The detection limits were 0.006, 0.003 and 0.0005 mg/mL, respectively, for the buffer‐containing system, the AOT‐applied system with phenol standard solutions in water and for the AOT‐applied system with phenol standard solutions in octane. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
4.
Occurrence of mycosporine-like amino acids in the red-tide dinoflagellate Alexandrium excavatum: UV-photoprotective compounds? 总被引:1,自引:0,他引:1
Carreto J.I.; Carignan M.O.; Daleo G.; Marco S.G.De 《Journal of plankton research》1990,12(5):909-921
Water extracts of the red-tide dinoflagellate Alexandrium excavatumgrown at high light intensity (200 µE m2s1) show a broad absorbance maximum in the UV regionof the spectrum (310360 nm). Using TLC and reverse-phaseHPLC a series of mycosporine-like amino acids have been characterized:mycosporine-glycine (max = 310 nm), palythine (max = 320 nm),asterina-330 (max = 330 nm), shinorine (max = 334 nm), porphyra-334(max= 334 nm), palythenic acid (max = 337 nm) and the isomericmixture of usujirene and palythene (max = 359 nm). From theobserved spectral changes during transference from low(20 µE m2 s1) to high (200µE m2 s1) light intensities and vice versa,the series of compounds are supposed to be biogenically relatedto one another. The presence of these compounds in A.excavatumis discussed in relation to their possible role in the photoprotectionto deleterious UV radiation. 相似文献
5.
Sorption of volatile C1 to C6 alkanols in plant cuticles 总被引:1,自引:1,他引:0
6.
Jason Y. Park Joshua Gunpat Li Liu Brooks Edwards Alana Christie Xian‐Jin Xie Larry J. Kricka Ralph P. Mason 《Luminescence》2014,29(6):553-558
Commercial chemiluminescent reagents emit across a broad portion of the electromagnetic spectrum (400–500 nm). A challenge to the use of chemiluminescence to monitor biological processes is the presence of interfering substances in the biological optical window. In the present study, longer wavelength emitting fluorophores (the organic dyes Alexa 568 and Alexa 647), and a semiconductor nanoparticle (QDOT800) were used to red‐shift the emission from commercially available 1,2‐dioxetane‐based chemiluminescent substrate reactions. By adding non‐conjugated fluorescent emitters into chemiluminescent reaction mixtures, an emission peak occurred at the predicted wavelength of the fluorescent emitter. The excitation and emission from QDOT800 was preserved in the presence of a 100 µm‐thick glass barrier separating it from the chemiluminescent reaction components. The maximum tissue phantom penetration by QDOT800 emission was 8.5 mm; in comparison, the native chemiluminescent emission at 500 nm was unable to penetrate the thinnest tissue phantom of 2.5 mm. The described method for red‐shifted emissions from chemiluminescent reactions does not require direct interaction between the chemiluminescent reaction and the fluorescent emitters. This suggests that the mechanism of chemiluminescent excitation of fluorophores and QDOT800 is not exclusive to chemiluminescence resonance energy transfer or sensitized chemiluminescence, but rather by broad energization from the native chemiluminescent emission. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
Guard cell protoplasts were isolated enzymatically from theepidermis of Vicia faba L. and their photosynthetic activitieswere investigated. Time courses of light-induced changes inthe chlorophyll a fluorescence intensity of these protoplastsshowed essentially the same induction kinetics as found formesophyll protoplasts of Vicia. The transient change in thefluorescence intensity was affected by DCMU, an inhibitor ofphotosystem II; by phenylmercuric acetate, an inhibitor of ferredoxinand ferredoxin NADP reductase; and by methyl viologen, an acceptorof photosystem I. Low temperature (77 K) emission spectra ofthe protoplasts had peaks at 684 and 735 nm and a shoulder near695 nm. A high O2 uptake (175 µmol mg1 Chl hr1)was observed in guard cell protoplasts kept in darkness, whichwas inhibited by 2 mM KCN or NaN3 by about 60%. On illumination,this O2 uptake was partially or completely suppressed, but itssuppression was removed by DCMU, which indicates that oxygenwas evolved (150 µmol mg1 Chl hr1) photosynthetically.We concluded that both photosystems I and II function in guardcell chloroplasts and that these protoplasts have high respiratoryactivity. (Received January 30, 1982; Accepted May 15, 1982) 相似文献
8.
Phytochrome in the Fern, Adiantum capillus-veneris L.: Spectrophotometric Detection in Vivo and Partial Purification 总被引:1,自引:0,他引:1
Spectrophotometric studies of fern phytochrome were performedusing dark-grown leaves of Adiantum. The absorbance differencespectrum between the red- and far-red-light irradiated sampleshowed a photoreversible absorbance change in the far-red region,with a maximum located at 728730 nm. The concentrationof phytochrome was highest at the leaf tips and decreased graduallyalong the leaf axis. As in the case of angiosperm phytochrome,the level of fern phytochrome decreased under continuous whitelight, and the level increased again when deetiolated tissuewas transferred back to the dark. When the fern tissue was exposedto a pulse of red light, the dark reversion of PFR to PR tookplace with almost no destruction of PFR. Phytochrome could beextracted from light-grown young leaves of the fern with a slightlyalkaline, aqueous buffer that contained 1 M NaCl. The differencespectrum of the partially purified phytochrome from fern wassimilar to that of partially degraded phytochrome from angio-sperms.A polyclonal antibody raised against phytochrome from etiolatedrye seedlings immuno-stained (albeit weakly) a 110-kDa polypeptideafter fractionation by SDS-polyacrylamide gel electrophoresisof the preparation of fern phytochrome. The band was very probablyfern phytochrome since it emitted zinc-induced fluorescence. (Received July 12, 1990; Accepted October 5, 1990) 相似文献
9.
SCHNABL HEIDE; WEISSENBOCK GOTTFRIED; SCHARF HELMUT 《Journal of experimental botany》1986,37(1):61-72
Cytological observations by fluorescence and U.V.-absorptionmicroscopy together with in vivo spectrophotometric analysesof stomata, guard cell protoplasts and epidermal cells of Viciafaba have shown that kaempferol 3,7-O-glycosides are localizedin the vacuoles. The alkaline-induced emission spectra recordedwith guard and epidermal cells after NH4OH-treatment were identical,exhibiting an emission maximum at 525 nm; the spectra correlatedwith that of reference flavonols after exposure to NH4OH Theexcitation spectra of both cell types are typical of these flavonolsshowing two maxima at 290 nm and 390 nm. In agreement, two absorptionmaxima were recorded for guard cells at 270 nm and 330 nm, withoutalkali, which shifted bathochromically to 275 nm and 380 nm,respectively, after NH4OH treatment. The fluorescence intensitymeasured at 525 nm demonstrates a photostability in epidermalcells whereas it increases by a factor of about five with theexcitation time up to 30 min in guard cells. For the latter,several possible processes are discussed. Key words: Alkaline-induced fluorescence, emission, excitation, U.V.-absorption spectra, kaempferol glycosides, cell specificity 相似文献
10.
The effect of UV-B radiation and humic substances on growth and motility of the flagellate, Euglena gracilis 总被引:2,自引:0,他引:2
The effects of ultraviolet-B radiation (UV-B, 250315nm) were determined on Euglena gracilis with respect to speed,phototactic orientation, specific growth rate, and in the presenceof humic substances. Humic substances had a protective effectwhen studying the speed and specific growth rate. However, thedegree of phototactic orientation decreased in UV-B radiationboth with and without humic substances. The inhibition of O2evolution and speed was most pronounced when using cutoff filtersWG280 and WG295. The photosynthetic inhibitor DCMU (106M) did not have any effect on the speed, but the 02 evolutiondecreased to zero. The effect of different wavelengths in theUV-B region on the speed of E.gracilis showed the maximum sensitivityat 280 and 290 nm. 相似文献
11.
The relationship between autolytic degradation of ß(13),(14)-D-glucanand acid pH-induced extension of isolated Zea mays cell wallshas been investigated using a constant-load extension technique.Acidic buffer (4.5) was able to induce an additional extension(Ea) on cell walls already extended at pH 6.8 buffer under a20 g-mass load, indicating that the additional extension (Ea)was the parameter that better represented the effect of thedifferent treatments on the mechanical properties of maize coleoptilecell walls. The additional extension in response to acidic pHwas higher when cell walls had been previously autolysed for24 h at pH 5.5. Furthermore, the acid-pH effect was dependenton the presence during the constant load extension of some thermo-labilefactors, suggesting the participation of expansins. Acid pHincreased Ea of native cell walls through an increase in theplastic extension (Ep) in agreement with a one step mechanismleading directly to irreversible (plastic) wall extension assuggested by Cosgrove (1977). The autolytic degradation of ß(13),(14)-D-glucan was also able to modify the mechanicalproperties of maize coleoptile cell walls increasing its elasticextension (Ee) in response to pH 4.5 buffer but that modificationonly leads to an increase in wall extension when expansins areactive, suggesting a cooperation between ß-glucanturnover and expansin action. (Received August 5, 1998; Accepted March 16, 1999) 相似文献
12.
Iwaki Masayo; Itoh Shigeru; Kamei Shoichiro; Matsubara Hiroshi; Oh-oka Hirozo 《Plant & cell physiology》1999,40(10):1021-1028
The absorption changes of chlorophyll (Chl) a-like pigments(C670) were studied by ns-ms laser spectroscopy at 77 K in theuntreated and urea-treated homodimeric reaction center (RC)complex of the green sulfur bacterium Chlorobium tepidum. Theuntreated RC complex contained 9 molecules of C670 in additionto 41 molecules of Bchl a and 0.9 molecules of menaquinone-7per one primary electron donor Bchl a dimer (P840). Upon photo-oxidationof P840, C670 showed an absorption change of a red-shift withan isosbestic wavelength at 668 nm. The absorption change ofP840 decayed with time constants (t1/e) of 55 and 37 ms at 283and 77 K, respectively, and was assigned to represent the chargerecombination between P840+ and FeS. In the urea-treatedRC complex, a bleach peaking at 670 nm with a shoulder peakat 662 nm, which is ascribable to the reduced primary electronacceptor A0, was detected after the laser excitationin addition to the shift at 668 nm indicating the formationof the P840+A0 state. The P840+A0 state decayedwith a t1/e of 43 ns at 77 K and produced a triplet state p840Tdue to the suppression of the forward electron transfer. Theseresults indicate the two different types of C670 species inthe RC complex; the one peaking at 670 nm functions as A0, whilethe other peaking at 668 nm shows the electrochromic shift,which presumably functions as the accessory pigment locatedin the close vicinity of P840. (Received May 17, 1999; Accepted July 14, 1999) 相似文献
13.
Proton Transport and pH Control in Sinapis alba Root Hairs: A Study carried out with Double-Barrelled pH Micro-electrodes 总被引:3,自引:0,他引:3
Continuous measurements of cytoplasmic pH (pHc) in Sinapis roothairs have been carried out with double-barrelled pH-micro-electrodesin order to gain information on translocation of protons acrossthe plasmalemma and cytoplasmic pH control. (i) The cytoplasmicpH of Sinapis (733 ? 012, standard conditions)changes no more than 0.1 pHc, per pHo-unit, regardless of whethercyanide is present or not. (ii) Weak acids rapidly acidify pHcand hyperpolarize, while weak bases alkalize pHc and depolarizethe cells, (iii) 1.0 mol M,3 NaCN acidifies the cytoplasm by0.4 to 0.7 pH-units, but alkalizes the vacuole. (iv) 20 mmolm3 CCCP has no significant effect on pHc, if added atpH 9.6 or 7.2, but acidifies pHc by 1.3 units at pH 4.3. Inthe presence of CCCP, cyanide acidifies the cytoplasm, (v) Chloridetransiently acidifies pHc, while K+, Na+, and have no significant effects, (vi) Cytoplasmic buffer capacityforms a bell-shaped curve versus pHc with an optimum of about50 mol m3 H+pHc-unit. The modes of proton re-entry and the effects of active and passiveproton transport on cellular pH control are critically discussed.It is suggested that the proton leak, consisting of H+-cotransport(e.g. H+/Cl) rather than H+-uniport, is no threat topHc. The proton export pump, although itself reacting to changesin pHc, influences pHc only to a minor extent. It is concludedthat buffer capacity and membrane transport play moderate rolesin pHc control in Sinapis, while the interlocked H+-producingand -consuming reactions of cellular metabolism are the mainregulating factors. This makes pH control in Sinapis quite differentfrom bacterial and animal cells. Key words: Cytoplasmic pH, double-barrelled pH micro-electrode, pH control, proton transport, Sinapis 相似文献
14.
The kinetic properties of phosphoenolpyruvate (PEP) carboxylasehave been studied among several Flaveria species: the C3 speciesF. cronquistii, the C3C4 species F. pubescens and F.linearis, and the C4 species F. trinervia. At either pH 7 or8, the maximum activities (in µmol.mg Chl1.h1)for F. pubescens and linearis (187513) were intermediateto those of the C3 species (1219) and the C4 species(2,1822,627). The response curves of velocity versusPEP concentration were hyperbolic for the C3 and C3C4species at either pH 7 or 8 while they were sigmoidal for theC4 species at pH 7 and hyperbolic at pH 8. The Km values forPEP determined from reciprocal plots were lowest in the C3 species,and of intermediate value in the C3C4 species comparedto the K' values of the C4 species determined from Hill plotsat either pH 7 or 8. Glucose-6-phosphate (G6P) decreased theKm values for PEP at both pH 7 and 8 in the C3 and C3C4species. In the C4 species, G6P decreased the K' values at pH8 but increased the K' values at pH 7. In all cases, G6P hadits effect by influencing the activity at limiting PEP concentrationswith little or no effect on the maximum activity. At pH 8 andlimiting concentrations of PEP the degree of stimulation ofthe activity by G6P was greatest in the C4 species, intermediatein F. linearis, a C3C4 species, and lowest in the C3species. In several respects, the PEP carboxylases of the C3C4Flaveria species have properties intermediate to those of theC3 and C4 species. (Received April 30, 1983; Accepted August 22, 1983) 相似文献
15.
Limitations to net photosynthesis as affected by nitrogen status in jack pine (Pinus banksiana Lamb.) seedlings 总被引:2,自引:0,他引:2
Relative limitations of nitrogen (N) status on the processescontributing to photosynthetic rate (A) were investigated. Jackpine {Pinus banksiana Lamb.) seedlings from seeds grown in sandculture were supplied with four different N treatments for 6weeks, which resulted in a needle N content ranging from 5085mmol m2 (1432 mg g1 dry weight). Leaf gasexchange at varying CO2 levels was measured and limitationson A350 (A at ambient CO2 level) caused by finite, limitingcarboxylation efficiency (c.e.), maximum A (Amax)and stomatalconductance were estimated from an analysis of the responseof A to internal CO2 concentration. Although c.e. and Amax decreasedlinearly with the decline in needle N, the magnitudes of theirchanges relative to A350 differed. Amax varied with A350 andalways exceeded A350 by 3738% c.e., however, declinedfaster than A350, as needle N level decreased. Consequently,relative limitation on A350 caused by inefficient Amax remainedconstant, but limitations caused by c.e. increased by 1015%at low N levels. In contrast, the limitation by stomatal conductancedeclined initially, but remained stable when N content droppedbelow 75 mmol m2. The results suggest: (1) a decreasein biochemical capacity, but not stomatal conductance, contributedto the reduction of A350 induced by N-deficiency in jack pineseedlings; and (2) the capacity of carboxylation appeared tobe impaired more than that of electron transport and/or photophosphorylationand its reduction may be the major reason for the reductionin A350. Key words: ACi analysis, carboxylation efficiency, electron transport, nitrogen deficiency, stomatal conductance 相似文献
16.
The Osmotic Pressure of Concentrated Solutions of Polyethylene Glycol 6000, and its Variation with Temperature 总被引:1,自引:0,他引:1
The vapour pressures of aqueous solutions of polyethylene glycol6000 have been measured (by equilibration with sucrose solutions)up to the saturation point at 25 °C (1.45 g g1 water).The reduced-osmotic-pressure (/c), when plotted versus concentration(c), rapidly and linearly increased up to a concentration ofabout 0.8 g g1 (crossing the similar plot for sucrose).Above this concentration, the reduced-osmotic-pressure rosemore slowly, but still more rapidly than sucrose. The maximumosmotic pressure achieved at saturation was nearly 18 MPa. Usingthe virial equation: /c= RT/M + RTA2c, the calculated secondvirial coefficient (A2) for the linear part is 4.5 x 103mol g1, a value slightly greater than most literaturevalues at 25 °C. Data are cited showing that A2 varies linearlyfrom 56 x 10x3 at 0 °C, to zero at 8090 °C 相似文献
17.
The distribution of radioactivity in Chlorella during dark 14CO2fixation was investigated either (a) in normal cells with andwithout added ammonium chloride, or (b) in nitrogen-starvedcells supplied with intermediates of the Krebs-Henseleit ureacycle. In the control experiments almost all the activity was presentin compounds of or associated with, the tricarboxylic acid cycle. The amino-acids citrulline and arginine became radioactive onlyin the presence of ammonia or ornithine where initially theycomprised 4060 per cent. of the total activity, reactionsof the KrebsHenseleit urea cycle being implicated intheir formation. No evidence could be found for a complete ureacycle. Unidentified compounds deriving their radioactivity fromthe C4 carbon of citrulline and/or arginine were detected andformed up to 40 per cent. of the total 14CO2 incorporated after25 min. 相似文献
18.
When grown in pots and well-watered, the relative growth ratesof the above ground parts of two species of Moricandia (M. arvensis,an intermediate C3C4 species, and M. moricandioides,a C3 species) were inferior to those of two cultivated Brassicaspecies (B. campestris and B. napus). The Moricandia specieshad thicker leaves (greater d.wt per unit leaf area) with morechlorophyll than the Brassica species and had slightly greaterrates of photosynthesis per unit leaf area at an irradiance(400700 nm) of 2000 µmol quanta m2 s 1.Leaves of M. arvensis, known to have a CO2 compensation pointbetween that of C3 and C4 species, had a lower ratio of theintercellular to atmospheric partial pressure of CO2 (C1/Ca)and a greater instantaneous water use efficiency (WUE) thanthose of M. moricandioides and the Brassica species. Carbon isotope discrimination ( 相似文献
19.
Kerr Carolyn L.; Ito Yushi; Manwell Stuart E.E.; Veldhuizen Ruud A.W.; Yao Li-Juan; McCaig Lynda A.; Lewis James F. 《Journal of applied physiology》1998,85(2):676-684
The effectsof both surfactant distribution patterns and ventilation strategiesutilized after surfactant administration were assessed in lung-injuredadult rabbits. Animals received 50 mg/kg surfactant via intratrachealinstillation in volumes of either 4 or 2 ml/kg. A subset ofanimals from each treatment group was euthanized for evaluation of theexogenous surfactant distribution. The remaining animals wererandomized into one of three ventilatory groups: group1 [tidal volume(VT) of 10 ml/kg with 5 cmH2O positive end-expiratorypressure (PEEP)]; group 2 (VT of 5 ml/kg with 5 cmH2O PEEP); orgroup 3 (VT of 5 ml/kg with 9 cmH2O PEEP). Animals wereventilated and monitored for 3 h. Distribution of the surfactant wasmore uniform when it was delivered in the 4 ml/kg volume. When thedistribution of surfactant was less uniform, arterial PO2 values were greater ingroups 2 and3 compared with group1. Oxygenation differences among the differentventilation strategies were less marked in animals with the moreuniform distribution pattern of surfactant (4 ml/kg). In bothsurfactant treatment groups, a high mortality was observed with theventilation strategy used for group 3.We conclude that the distribution of exogenous surfactant affects theresponse to different ventilatory strategies in this model of acutelung injury. 相似文献
20.
In studies of Trifolium repens nitrogen nutrition, the controlof nutrient solution pH using dipolar buffers, was evaluatedin tube culture under sterile conditions. Five buffers; MES,ADA, ACES, BES and MOPS with pK2s (20 °C) of 6.15, 6.60,6.90, 7.15 and 7.20 respectively, at a concentration of 2.0mol m3, were provided to inoculated Trifolium repensgrowing in nutrient solution containing 7.13 mol m3 nitrogenas (NH4)2SO4. Initial pH of each solution was adjusted to theappropriate buffer pK2 Two buffers, ADA and ACES completelyinhibited plant growth. The remaining buffers had little effectin limiting pH change, although plant dry matter was higherand nodule numbers lower in the presence of these buffers. MESand MOPS were supplied to nutrient solutions with and without7.13 mol m3 (NH4)2SO4, at concentrations ranging from012 mol m3. MES at 9 mol m3 and 12 molm3 reduced growth of plants reliant on the symbiosisfor providing nitrogen. The provision of MES to plants providedwith NH4+ significantly increased plant yield and reduced nodulenumber at all concentrations. MOPS did not affect plant yieldor nodule number. The use of dipolar buffers in legume nitrogennutrition studies is considered in terms of buffering capacity,and the side effects on plant growth and symbiotic development. Key words: Ammonium, Dipolar buffer, Nitrogen nutrition, pH control, Symbiosis, Trifolium repens 相似文献