Crystalloid formation in protochlorophyll-accumulating plastids from the inner seed coat of Cyclanthera explodens

The development of fruit, seed and plastids in the inner seed coat of Cyclanthera explodens Naud. was studied. Large amounts of protochlorophyll, in at least three different in vivo-forms, accumulated during maturation and was 14 mg/g fresh weight of the inner seed coat in mature seeds. In earlier stages plastid-membrane-lipids increased simultaneously with the pigment. This could also be seen in electron micrographs as an increased amount of membranes. During later stages the amount of pigment continued to increase without an increase in the lipids. At this stage large crystalloids were found in the plastids. The data presented led to the conclusion that the protochlorophyll form fluorescing at 691 nm is crystalline.     

A long-wavelength absorbing form of protochlorophyll and crystalloids in the inner seed coat of Luffa cylindrica

The inner seed coat of seeds of Luffa cylindrica (L.) Roem. (cv. Luffa sponge vine) was used to study the development of the protochlorophyll-containing plastids during different stages of maturity of the fruits. The inner seed coats had an absorption spectrum with a main peak in the red region at 675 nm and a shoulder at 630 nm. The fourth derivative spectrum gave a clear peak at 630 nm and also a small additional peak at 650 nm. An acetone extract showed a peak at 626 nm and a Soret band at 440 nm indicating that the main pigment in the seed coat was protochlorophyll. The ultrastructure of the protochlorophyll-containing plastids changed during maturation of the seed. In the young stage an elaborate membrane system was present. In a more mature stage the membrane system degenerated and crystalloids were formed. Some of these crystalloids seemed to develop into plastoglobuli in the most mature stage.     

Events Surrounding the Early Development of Euglena Chloroplasts: VI. Action Spectra for the Formation of Chlorophyll, Lag Elimination in Chlorophyll Synthesis, and Appearance of TPN-dependent Triose Phosphate Dehydrogenase and Alkaline DNase Activities

Action spectra derived from dose-response curves measured for various processes associated with chloroplast development in Euglena gracilis var. bacillaris are presented. The action spectrum for chlorophyll synthesis during the first 36 hours of continuous illumination of dark-grown resting cells resembles the absorption spectrum of protochlorophyll(ide). The action spectrum for the preillumination phase of potentiation, during which preillumination followed by a dark period brings about lag elimination in chlorophyll synthesis when the cells are subsequently exposed to postilluminating light, shows a high peak in the blue region (at about 433 nm) with a small peak in the yellow-orange region (at about 597 nm); the postillumination phase yields an action spectrum very similar to that obtained for chlorophyll synthesis in continuous light in normal, unpotentiated cells, with peaks at 433 and 631 nm. Alkaline DNase and TPN-linked triose phosphate dehydrogenase, two plastid enzymes which are synthesized outside the chloroplast, yield action spectra which are consistent with protochlorophyll(ide) being the major light receptor. The action spectra which implicate pigments resembling protochlorophyll(ide) holochrome have blue to red peak ratios in the vicinity of 5:1 as does the absorption spectrum of the protochlorophyllide holochrome from beans; the action spectrum is not identical with the holochrome spectrum indicating that the Euglena holochrome may differ from the bean pigment in details of its absorption spectrum. The action spectrum for preillumination, shows a ratio of the blue peak to the red effectiveness of about 24:1. This suggests that preillumination is controlled by a photoreceptor different from the protochlorophyll(ide) holochrome.     

THE EFFECTIVENESS OF THE SPECTRUM IN CHLOROPHYLL FORMATION

1. Although the carotenoid pigments are present in large concentration in the plastids of etiolated Avena seedlings as compared with protochlorophyll, the pigment precursor of chlorophyll, it is possible to show that the carotenoids do not act as filters of the light incident on the plant in the blue region of the spectrum where they absorb heavily. This suggests that the carotenoids are located behind the protochlorophyll molecules in the plastids. 2. Since the carotenoids do not screen and light is necessary for chlorophyll formation, an effectiveness spectrum of protochlorophyll can be obtained which is the reciprocal of the light energy necessary to produce a constant amount of chlorophyll with different wavelengths. The relative effectiveness of sixteen spectral regions in forming chlorophyll was determined. 3. From the effectiveness spectrum, one can conclude that protochlorophyll is a blue-green pigment with major peaks of absorption at 445 mµ, and 645 mµ, and with smaller peaks at 575 and 545 mµ. The blue peak is sharp, narrow, and high, the red peak being broader and shorter. This differs from previous findings where the use of rougher methods indicated that red light was more effective than blue and did not give the position of the peaks of absorption or their relative heights. 4. The protochlorophyll curve is similar to but not identical with chlorophyll. The ratio of the peaks of absorption in the blue as compared to the red is very similar to chlorophyll a, but the position of the peaks resembles chlorophyll b. 5. There is an excellent correspondence between the absorption properties of this "active" protochlorophyll and what is known of the absorption of a chemically known pigment studied in impure extracts of seed coats of the Cucurbitaceae. Conclusive proof of the identity of the two substances awaits chemical purification, but the evidence here favors the view that the pumpkin seed substance, which is chemically chlorophyll a minus two hydrogens, is identical with the precursor of chlorophyll formation found in etiolated plants.     

Action Spectra for Transformation and Fluorescence of Protochlorophyll Holochrome from Bean Leaves

The action spectrum from 232 to 687 nm was determined for the transformation of protochlorophyllide into chlorophyllide a in solutions of protochlorophyll holochrome Fran bean leaves. The whole ultraviolet region is effective. The peaks at 445 and 639 nm have a height ratio of 4.0. Only radiation absorbed in the protochlorophyllide itself is effective in transformation (absorption in aromatic amino acids of the protein and in carotenoids is ineffective). The activation spectra for fluorescence at 643 and 683 nm are measured for the holochrome before and after transformation, as well as the change in absorption spectrum that takes place upon transformation. By combining the various measurements the spectrum of inactive (non-transformable) protochlorophyllide (peak at 440 nm) and the holochromatic chlorophyllide a are derived. In the latter spectrum the peaks at 419 and 435 nm are of about the same height.     

Physiological and Biochemical Changes in Microcystis aeruginosa Qutz. in Phosphorus Limitation

Effects of phosphorus limitation on the physiological and biochemical changes of the freshwater bloom alga Microcystis aeruginosa Qutz. are reported in the present study. As a result of phosphorus limitation, biomass was controlled to some extent and the protein content per cell in vivo decreased. However,the carbohydrate content per cell was higher in phosphorus limitation over the 8d of cultivation. Soluble proteins were distinct in the media, whereas phosphorus deficiency induced the presence of a unique protein (16.2 kDa). Under conditions of phosphorus limitation, the activities of both superoxide dismutase and peroxidase per cell in vivo were lower than under normal conditions in the last cultivation. The in vivo absorption spectra of cells showed chlorophyll absorption peaks at 676 and 436nm, over 10nm red-shifted from the normal position; cells showed an absence of a chlorophyll c with an in viva absorption peak at 623nm and an extraction absorption peak at 617nm. The chlorophyll a/carotene and chlorophyll a/xanthophylls ratios decreased under conditions of phosphorus limitation, photosynthetic efficiency (Fv/Fm) was clearly lower, and the low-temperature fluorescence emission spectra indicated a higher peak at 683nm and a lower peak at 721nm relatively, with the 721nm peak drifting slightly to the red and the 683 nm peak strengthened with a weakened 692nm shoulder peak.     

Action spectra for C-glucosylflavone accumulation in Hordeum vulgare plumules

Five-day-old etiolated barley plumules contain the C-glucosylflavones saponarin, lutonarin, and lutonarin 3′-methyl ether. When harvested 24 hr after illumination, increased flavonoid levels were essentially linear with increased energies of monochromatic light at seven wavelengths between 450 and 750 nm. Action spectra for saponarin and for a mixture of lutonarin and its 3′-methyl ether were determined between 380 and 760 nm at 6.6 kerg·cm^?2. The saponarin action spectrum showed distinct peaks at 620 and at 660 nm. These two peaks were similar in their photoreversibility when followed by either 6·6 or 34 kerg·cm^?2 of far-red light. Phytochrome is apparently the photoreceptor for the saponarin action spectrum. Lutonarin and its 3′-methyl ether showed peaks at 520 580, 620 and near 660 nm. The 660 nm peak was not photoreversible by 6·6 kerg·cm^?1, but was by 34 kerg·cm_?2, of far-red light. Phytochrome and protochlorophyll are the likely photoreceptors for these 3′-substituted flavonoids.     

Analyses of absorption and fluorescence spectra of water-soluble chlorophyll proteins,pigment System II particles and chlorophyll a in diethylether solution by the curve-fitting method

Absorption and fluorescence spectra in the red region of water-soluble chlorophyll proteins, Lepidium CP661, CP663 and Brassica CP673, pigment System II particles of spinach chloroplasts and chlorophyll a in diethylether solution at 25°C were analyzed by the curve-fitting method (French, C.S., Brown, J.S. and Lawrence, M.C. (1972) Plant Physiol. 49, 421–429). It was found that each of the chlorophyll forms of the chlorophyll proteins and the pigment System II particles had a corresponding fluorescence band with the Stokes shift ranging from 0.6 to 4.0 nm.The absorption spectrum of chlorophyll a in diethylether solution was analyzed to one major band with a peak at 660.5 nm and some minor bands, while the fluorescence spectrum was analyzed to one major band with a peak at 664.9 nm and some minor bands. A mirror image was clearly demonstrated between the resolved spectra of absorption and fluorescence. The absorption spectrum of Lepidium CP661 was composed of a chlorophyll b form with a peak at 652.8 nm and two chlorophyll a forms with peaks at 662.6 and 671.9 nm. The fluorescence spectrum was analyzed to five component bands. Three of them with peaks at 654.8, 664.6 and 674.6 nm were attributed to emissions of the three chlorophyll forms with the Stokes shift of 2.0–2.7 nm. The absorption spectrum of Brassica CP673 had a chlorophyll b form with a peak at 653.7 nm and four chlorophyll a forms with peaks at 662.7, 671.3, 676.9 and 684.2 nm. The fluorescence spectrum was resolved into seven component bands. Four of them with peaks at 666.7, 673.1, 677.5 and 686.2 nm corresponded to the four chlorophyll a forms with the Stokes shift of 0.6–4.0 nm. The absorption spectrum of the pigment System II particles had a chlorophyll b form with a peak at 652.4 nm and three chlorophyll a forms with peaks at 662.9, 672.1 and 681.6 nm. The fluorescence spectrum was analyzed to four major component bands with peaks at 674.1, 682.8, 692.0 and 706.7 nm and some minor bands. The former two bands corresponded to the chlorophyll a forms with peaks at 672.1 and 681.6 nm with the Stokes shift of 2.0 and 1.2 nm, respectively.Absorption spectra at 25°C and at ?196°C of the water-soluble chlorophyll proteins were compared by the curve-fitting method. The component bands at ?196°C were blue-shifted by 0.8–4.1 nm and narrower in half widths as compared to those at 25°C.     

Chlorophyll-Protein Complexes of Blue-Green Algae Isolated by a New Gel Electrophoresis System with High Resolving Power

At least 13 chlorophyll bands from the thylakoid membranes of blue-green algae could be clearly resolved by SDS-PAGE employing a new improved procedure. They were designated as CPIa, CPIb, CPIc, CPId, CPIe, CPIf, CPIg, CHIh, CPal, CPa2, CPa3, CPa4 and FC. 8 chlorophyll-protein complexes, CPIa-CPIh, had the same absorption spectrum at 676 nm in the red and 436 nm in the blue region. They belonged to the chlorophyll-protein complexes of PS Ⅰ. 4 chlorophyll-protein complexes, CPal-CPa4, had a red absorption peak at 670­672 nm and a blue one at 436 nm. Their fluorescence emission peak at 77K was at 685 nm. They were chlorophyll-protein complexes of PS Ⅱ.     

Action Spectrum between 250 and 800 Nanometers for the Photoinduced Inhibition of Spore Germination in Pteris vittata

An action spectrum between 250 and 800 nm for the inhibitionof red-light-induced germination of spores in the fern Pterisvittata was determined on the Okazaki Large Spectrograph. Theresultant spectrum showed prominent peaks of effectiveness atabout 370, 440 and 730 nm and a minor peak in the neighborhoodof 260 nm. Next, a brief red light irradiation was given immediatelyafter the monochromatic irradiation to cancel the inhibitoryeffect caused by simultaneously formed P_R. This resulted ina complete disappearance of the peak at 730 nm and considerabledecrease of other peaks in the shorter wavelength region exceptat 260 nm. Further correction of the latter spectrum by consideringthe transmission spectrum of a spore coat revealed that 260nm light acted more effectively than lights of 370 and 440 nm.The inhibitory effect of UV light on spore germination was nullifiedby subsequent irradiation with red light for 24 h or darknessfor 48 h followed by a brief red irradiation, indicating thatthe inhibitory action of UV light was ascribable to a blue-ultraviolet light-absorbing pigment. ⁴Present address (KT) and permanent address (MF): Botany Department,Faculty of Science, University of Tokyo, Hongo, Tokyo 113, Japan. (Received July 30, 1983; Accepted November 21, 1983)     

Characterization of chlorophyll–protein complexes isolated from a Siphonous green alga, Bryopsis corticulans

Six chlorophyll–protein complexes are isolated from thylakoid membranes of Bryopsis corticulans by dodecyl-β-d-maltoside polyacrylamide gel electrophoresis. Unlike that of higher plants, the 77 K fluorescence emission spectrum of the CP1 band, the PSI core complexes of B. corticulans, presents two peaks, one at 675 nm and the other at 715–717 nm. The emission peak at 715–717 nm is slightly higher than that at 675 nm in the CP1 band when excited at 438 or 540 nm. However, the peak at 715 nm is obviously lower than that at 675 nm when excited at 480 nm. The excitation spectra of CP1 demonstrate that the peak at 675 nm is mainly attributed to energy from Chl b while it is the energy from Chl a that plays an important role in exciting the peak at 715–717 nm. Siphonaxanthin is found to contribute to both the 675 nm and 715–717 nm peaks. We propose from the above results that chlorophyll a and siphonaxanthin are mainly responsible for the transfer of energy to the far-red region of PSI while it is Chl b that contributes most of the transfer of energy to the red region of PSI. The analysis of chlorophyll composition and spectral characteristics of LHCP¹ and LHCP³ also indicate that higher content of Chl b and siphonaxanthin, mainly presented in LHCP¹, the trimeric form of LHCII, are evolved by B. corticulans to absorb an appropriate amount of light energy so as to adapt to their natural habitats.     

Red region excitation spectra of protochlorophyllide in dark-grown leaves from plant species with different proportions of its spectral forms

Etiolated leaves of three different species, maize, wheat, and pea, as well as a pea mutant (lip1) were used to compare the excitation spectra of protochlorophyllide (Pchlide) in the red region. The species used have different composition of short-wavelength and long-wavelength Pchlide forms. The relation between different forms was furthermore changed through incubating the leaves in 5-aminolevulinic acid (ALA), which caused an accumulation of short-wavelength Pchlide forms, as shown by changes in absorption and fluorescence spectra. This is the first time a comprehensive comparison is made between excitation spectra from different species covering an emission wavelength range of 675–750 nm using fluorescence equipment with electronic compensation for the variations in excitation irradiance. The different forms of Pchlide having excitations peaks at 628, 632, 637, 650, and 672 nm could be best measured at 675, 700, 710, 725, and 750 nm, respectively. Measuring emission at wavelengths between 675– 710 nm gave an exaggeration of the short-wavelength forms and measuring at longer wavelengths gave for the pea leaves an exaggeration of the 672 nm peak. In general, an energy transfer from short-wavelength Pchlide forms to long-wavelength Pchlide forms occurred, but such an energy transfer sometimes seemed to be limited as a result of a discrete location of the Pchlide spectral forms. The excitation spectra resembling the absorption spectrum most were measured at an emission wavelength of 740 nm. Measuring the excitation at 710 nm gave higher intensity of the spectra but the short-wavelength forms were accentuated.     

A protein–protochlorophyll complex obtained from inner seed coats of Cucurbita pepo: The resolution of its two pigment groups into true protochlorophyll and a pigment related to bacterial protochlorophyll

1. The inner seed coats of Cucurbita pepo were extracted with aqueous acetone and found to contain pigments with spectra similar to that of protochlorophyll. 2. When the fruits of C. pepo were stored the amount of protochlorophyll-like material in the inner seed coats increased and a form of protochlorophyll absorbing at longer wavelength was apparently formed. 3. The pigment was resolved into two forms of protochlorophyll by chromatography on sugar columns. One form with absorption maxima in ether at 432, 535, 571 and 623mmu was spectroscopically identical with plant protochlorophyll; the other, with absorption maxima at 438, 537, 574 and 624mmu, was spectroscopically identical with bacterial protochlorophyll isolated from the tan mutant of Rhodopseudomonas spheroides. The two phaeoporphyrins obtained from the seed-coat pigments closely resemble the corresponding phaeoporphyrin derivatives of plant protochlorophyll and bacterial protochlorophyll in spectroscopic and partition properties. 4. The pigment in the cells of inner seed coat of C. pepo is concentrated in discrete particles of about 1.7mu diameter. Extracts of the seed coats in a glycerol-glycine buffer were similar in spectroscopic properties to the crude protochlorophyll holochrome, but were not light-transformable. 5. After partial purification of the glycerol-glycine buffer extracts a pigment-protein complex was obtained with absorption maxima at considerably longer wavelengths than in organic solvents. 6. Preparations of the seed-coat protochlorophyll, in the presence of bovine serum albumin, adsorbed on filter paper or in colloidal solution, did not have absorption bands shifted so far to the red region as the natural protein complex isolated from the seed coat. 7. It is suggested that bacterial protochlorophyll (magnesium 2,4-divinylphaeoporphyrin a(5) methyl ester) is involved in the biosynthesis of chlorophyll in both plants and photosynthetic bacteria.     

Protochlorophyll forms in roots of dark-grown plants

Protochlorophyll was found in roots of dark-grown plants of seven species investigated. It was identified by absorbance and fluorescence spectra of acetone and ether extracts. Chlorophyll was also found in roots of one pea species. The concentration of protochlorophyll was usually highest in young root tips and decreased upwards along the roots. The maxima of the in vivo absorbance spectra of the species studied varied between 634 and 638 nm. Low temperature in vivo fluorescence emission spectra had two maxima, one at ca 633 and the other at ca 642 nm, when the wavelengths of the excitation light were 440 and 460 nm, respectively. In vivo fluorescence excitation spectra displayed a shift of the excitation maximum from 438 to 445 nm, when emission varied from 620 to 647.5 nm. Deconvolution of these three types of spectra into Gaussian components made it possible to identify two spectral forms of protochlorophyll: protochlorophyll_629–633 and protochlorophyll_638–642.     

Comparison of the spectral emission of lux recombinant and bioluminescent marine bacteria

The purpose of the present paper was to study the influence of bacteria harbouring the luciferase‐encoding Vibrio harveyi luxAB genes upon the spectral emission during growth in batch‐culture conditions. In vivo bioluminescence spectra were compared from several bioluminescent strains, either naturally luminescent (Vibrio fischeri and Vibrio harveyi) or in recombinant strains (two Gram‐negative Escherichia coli::luxAB strains and a Gram‐positive Bacillus subtilis::luxAB strain). Spectral emission was recorded from 400 nm to 750 nm using a highly sensitive spectrometer initially devoted to Raman scattering. Two peaks were clearly identified, one at 491–500 nm (± 5 nm) and a second peak at 585–595 (± 5 nm) with the Raman CCD. The former peak was the only one detected with traditional spectrometers with a photomultiplier detector commonly used for spectral emission measurement, due to their lack of sensitivity and low resolution in the 550–650 nm window. When spectra were compared between all the studied bacteria, no difference was observed between natural or recombinant cells, between Gram‐positive and Gram‐negative strains, and growth conditions and growth medium were not found to modify the spectrum of light emission. Copyright © 2003 John Wiley & Sons, Ltd.     

Oak seedlings grown in different light qualities

Oak seedlings (Quercus robur L.) were germinated in darkness for 3 weeks and then given continuous long wavelength far-red light (LFR; wavelengths longer than 700 nm). A control group of seedlings was kept in darkness. After 2 additional weeks the chlorophyll formation ability in red light was examined in the different seedlings. The stability of the protochlorophyll(ide) and chlorophyll(ide) forms to high intensity red irradiation was also measured. Oak seedlings grown in darkness accumulated protochlorophyll(ide) (6 μg per g fresh matter). Absorption spectra and fluorescence spectra indicated the presence of more protochlorophyll(ide)_628–632 than protochlorophyllide_650–657. The level of protochlorophyll(ide) was higher in leaves of plants cultivated in LFR light (13 μg per g fresh matter) than in leaves of dark grown plants. 12% of the protochlorophyll(ide) was esterified in both cases. The level of protochlorophyll(ide)_628–632 in LFR grown oaks varied with the age of the leaves, being higher in the older (basal) leaves, but also in the very youngest (top-most) leaves. The ability of the leaves to form photostable chlorophyll in red light showed a similar age dependence, being low in rather young and in older leaves. A low ability to form photostable chlorophyll thus appears to be correlated with a high content of protochlorophyll(ide)_628–632. Upon irradiation only the protochlorophyllide_650–657 was transformed to chlorophyllide. After this phototransformation the chlorophyllide peak at 684 nm shifted to 671 nm within about 30 min in darkness. This shift took place without any accompanying change in photostability of the chlorophyll(ide). Upon irradiation with strong red light a similar shift took place within one minute. This indicates that the chlorophyllide after phototransformation was rather loosely bound to the photoreducing enzyme. The development towards photostable chlorophyll forms consists of three phases and is discussed.     

The Chlorophyll-Protein Complexes Resolved from Ultrasonically Broken Thylakoid Memb-ranes of Blue-Green Algae

When the thylakoid membranes of blue-green algae were broken by ultrasonic vibrations and subjected to polyacrylamide gel electrophoresis at 4℃, six green zones were resolved. They were designated as CPIa, CPlb, CPI; CPal, CPa2, and FC. The absorption spectrum of CPI had a red maximum at 674 nm and a peak in the blue at 435 nm. It was identified as PS chlorophyll a-protein Complex, but was contaminated with minor PSⅡ which was implied by the appearance of fluorescence emission peak at 680 nm besides the main one at 725 nm at 77 K. The spectral properties of CPIa and CPlb were similar to that of CPl. The absorption spectra of CPa1 and CPa2 were similar, both having red maxima at 667 nm and peaks in the blue at 431.5 nm. Their fluorescence emission had the same peaks at 684 nm at 77 K indicating that they belonged to PSⅡ. It was recognized that CPal of 47 kD is the reaction center complex of photosystem Ⅱ and CPa2 of 40 kD is the internal antenna complex of photosystem Ⅱ. The spectral characteristics of the chlorophyll-protein complexes resolved by ultrasonic method were similar to those of the same complexes resolved by SDS solubilization, except the absorbance positions of CPa1 and CPa2 in the blue peak and the red one which shifted to blue about 3–5 nm. It was calculated that in thylakoid membranes of blue-green algae 40.93% chlorophyll was in PSⅠ, while 38.78% of chlorophyll in PSⅡ. The difference of chlorophyll contents between PSⅠ and PSⅡ was only 2.15%. Concerning the fact that minor PSⅡ compound remained in the part of PSⅠ zones, it might be concluded that the distribution of chlorophyll between PSⅠ and PSⅡ in blue-green algae was equal. This result was in agreement with the hypothesis that PSⅠ and PSⅡ operates in series in photosynthetic electron transport.     

Carbamylation of human HbF on carboxy methyl cellulose column in 8 M urea pH 6.7

Myeloperoxidase-H₂O₂-indole acetate system at pH 7.4 emitted light in visible region. Luminescent spectrum showed a weak peak at or near 480 nm and prominent peaks at or near 550, 580, and 620 nm with deep troughs near 500 and 600 nm. In some cases, no definite peak emissions near 550 and 580 nm, but a prominent broad emission between 550 and 580 nm, is observed. Such spectral patterns in the region of 510 to 620 nm were quite similar to those report for the luminescence of photo-products formed from the indole analogs (tryptophan and indole) in 50% alcohol irradiated by U.V. (365 nm) at 77°K, assuming red shift (20–25 nm) by solvent effect. Possible formation of indole acetate cation radical (a precursor of excited indole acetate) was discussed.     

Discovery of signaling effect of UV-B/C light in the extended UV-A/blue-type action spectra for step-down and step-up photophobic responses in the unicellular flagellate algaEuglena gracilis

Summary Cultures of unicellular algal flagellateEuglena gracilis grown in different conditions were subjected to action spectroscopy for step-down and step-up photophobic responses, respectively. The spectral region was extended into the UV-B/C as well as in the UV-A and visible regions with the Okazaki Large Spectrograph as the monochromatic light source. The photophobic responses of the cells were measured with an individual-cell assay method with the aid of a computerized video motion analyzer. In the UV-A and visible regions, the shapes of the action spectra were the so-called UV-A/blue type. In the newly studied UV-B/C region, new action peaks were found at 270 nm for the step-down response and at 280 nm for the step-up one. The absorption spectrum of flavin adenine dinucleotide (FAD) appeared to fit the action spectrum for the step-up response, whereas the shape of the step-down action spectrum, which has a UV-A peak (at 370 nm) higher than the blue peak (at 450 nm), appeared to be mimicked by the absorption spectrum of a mixed solution of 6-biopterin and FAD. These observations might also account for the fact that the UV-B/C peak wavelength at 270 nm of the action spectrum for the step-down response is shorter by 10 nm than the action spectrum for the step-up response at 280 nm.Abbreviations FAD flavin adenine dinucleotide - FWHM spectral full width at half maximum - NIBB National Institute for Basic Biology - OLS Okazaki Large Spectrograph - PFB paraflagellar body - UV-A ultraviolet light of spectral region between 320 and 400 nm - UV-B/C ultraviolet light of spectral region between 190 and 320 nm     

Analyses of absorption and fluorescence spectra of water-soluble chlorophyll proteins, pigment system II particles and chlorophyll a in diethylether solution by the curve-fitting method.

Absorption and fluorescence spectra in the red region of water-soluble chlorophyll proteins, Lepidium CP661, CP663 and Brassica CP673, pigment System II particles of spinach chloroplasts and chlorophyll a in diethylether solution at 25 degrees C were analyzed by the curve-fitting method (French, C.S., Brown, J.S. and Lawrence, M.C. (1972) Plant Physiol 49, 421--429). It was found that each of the chlorophyll forms of the chlorophyll proteins and the pigment System II particles had a corresponding fluorescence band with the Stokes shift ranging from 0.6 to 4.0 nm. The absorption spectrum of chlorophyll a in diethylether solution was analyzed to one major band with a peak at 660.5 nm and some minor bands, while the fluorescence spectrum was analyzed to one major band with a peak at 664.9 nm and some minor bands. A mirror image was clearly demonstrated between the resolved spectra of absorption and fluorescence. The absorption spectrum of Lepidium CP661 was composed of a chlorophyll b form with a peak at 652.8 nm and two chlorophyll a forms with peaks at 662.6 and 671.9 nm. The fluorescence spectrum was analyzed to five component bands. Three of them with peaks at 654.8, 664.6 and 674.6 nm were attributed to emissions of the three chlorophyll forms with the Stokes shift of 2.0--2.7 nm. The absorption spectrum of Brassica CP673 had a chlorophyll b form with a peak at 653.7 nm and four chlorophyll a forms with peaks at 662.7, 671.3, 676.9 and 684.2 nm. The fluorescence spectrum was resolved into seven component bands. Four of them with peaks at 666.7, 673.1, 677.5 and 686.2 nm corresponded to the four chlorophyll a forms with the Stokes shift of 0.6--4.0 nm. The absorption spectrum of the pigment System II particles had a chlorophyll b form with a peak at 652.4 nm and three chlorophyll a forms with peaks at 662.9, 672.1 and 681.6 nm. The fluorescence spectrum was analyzed to four major component bands with peaks at 674.1, 682.8, 692.0 and 706.7 nm and some minor bands. The former two bands corresponded to the chlorophyll a forms with peaks at 672.1 and 681.6 nm with the Stokes shift of 2.0 and 1.2 nm, respectively. Absorption spectra at 25 degrees C and at --196 degrees C of the water-soluble chlorophyll proteins were compared by the curve-fitting methods. The component bands at --196 degrees C were blue-shifted by 0.8--4.1 nm and narrower in half widths as compared to those at 25 degrees C.