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Elemental abundances of prokaryotic and eukaryotic cells as well as organelles were provided as the number of atoms per cell (or organelle). In order to examine the specific uptake of vital elements by cells, E. coli cells were grown in different media and harvested at several time points during the cell growth and proliferation. The major-to-ultratrace elements in the cells were determined by micro-flow injection (μFI)-ICP-MS after microwave-assisted acid digestion of less than 10 mg of dry weight sample. Cyanobacteria and chlorella were also cultivated to compare elemental abundance differences among species. In addition, to further examine the localization and utilization of vital elements in the cells, chloroplasts and mitochondria were isolated from the tissues of spinach leaves, potato tuber, and bovine liver by density-gradient centrifugation using Percoll. The concentration data obtained by ICP-MS measurements were normalized to a per cell (or organelle) basis, taking into account the cell size and water content. Among about 60 elements detectable by ICP-MS, more than 30 elements were quantitatively determined, and it was clearly found that essential elements participating in specific vital functions such as redox reactions were highly accumulated in the microorganisms and organelles.

Flower color in hydrangea is well known to vary greatly. The blue color might develop with aluminum ion (Al 3+ ) from soil; the blue pigment in sepals is an Al-complex with delphinidin 3-glucoside and 5-caffeoyl quinic acid. To clarify the correlation between blue color development and Al-tolerance, flower color and metal content of the sepals were examined with reference to the reflection spectrum and ICP-AES. Blue sepals were found to contain more than 100 ppm Al, and red ones was less than 50 ppm. Change of several element contents along the flower growing stage was also observed. In blue sepals Al ions increased with maturation, but, in red counterpart s the same level was maintained. The content of Fe in blue and red sepals showed a similar behavior to that of Al. However, reconstruction experiments suggested that Al may be responsible for the blue color. Al accumulation and blue color development might reflect a detoxification mechanism for Al in tolerant plants.

Iodoacetamide and its spin-labeled derivative in high concentration ranges (10−2−10−1M) react with unexposed SH-groups of rhodopsin in the dark. The spin-labels bound to these SH-groups are moderately immobilized. While rhodopsin is not spin-labeled with the iodoacetamide at a lower concentration (5 × 10−4 m) in the dark, photobleached rhodopsin is readily spin-labeled with this concentration. The photo-bound spin-labels are highly immobilized and do not change their mobility after the regeneration of rhodopsin. Urea enhances the dark-bleaching of rhodopsin by iodoacetamide and increases the mobility of the bound spin-labels. The dark-reacting unexposed SH-groups appear to be different from the photo-exposed SH-groups which are not directly involved in the 500-nm chromophore.

Carcinogenic hydrocarbons benz[ a ]anthracene (BA), 7,12-dimethyl-BA (DMBA) and 3-methylcholanthrene (MC), bound non-covalently to bovine serum albumin (BSA), are photo-oxidized and become covalently bound to the protein as a result of irradiation at 365 nm. BSA with covalently-bound hydrocarbon photoproducts can be isolated by SDS-gel filtration after repeated ether extraction. In this photo-oxidation, BA and DMBA are converted apparently to phenanthrene-type products together with some other photoproduct in the case of BA, whereas MC produced a naphthalene-like photoproduct and an intact molecule bound to BSA. Our findings suggest that these hydrocarbons can undergo photo-activation and macro-molecular binding as in metabolic activation.

When B- and R-phycoerythrins and their subunits are treated with high concentrations of an organic mercurial, all chromophores including the 500-nm chromophore are converted to a similar form exhibiting two absorption bands as well as two positive CD bands at 525 and 558 nm. This ultimate chromophore state is similar to that obtained from C-phycoerythrin treated in the same way. This adds further support to the contention that the different chromophore types are due to phycoerythrobilin residues located in three different protein environments. Upon removal of mercurial with mercaptoethanol, regeneration of the original types of chromophore is only partially effected.

1. 1. The effect of a mercurial on circular dichroism (CD) of B-phycoerythrin, R-phycoerythrin and C-phycocyanin has been investigated. 2. 2. B-phycoerythrin exhibits a double CD band centered at the longest wavelength absorption. Upon treatment with a mercurial, the double CD band appears to reverse its sign resulting in a different double CD band shifted toward shorter wavelengths. 3. 3. R-phycoerythrin, having three positive CD bands, lacks the double CD band both before and after mercurial treatment. 4. 4. C-phycocyanin from Anacystis nidulans shows two positive CD bands. The longer wavelength CD band at pH 5 is much greater than the shorter wavelength band. At pH 7, where both bands are of about the same intensity and are well separated, the longer wavelength CD band shifts to a shorter wavelength in the presence of a mercurial. 5. 5. Subsequent addition of mercaptoethanol brings about a partial regeneration of the longest wavelength positive CD band in the case of both R-phycoerythrin and C-phycocyanin but not with mercurial-treated B-phycoerythrin which produces a double CD band of opposite sign. 6. 6. These CD changes are discussed in connection with absorption spectral changes as well as with the dissociation and association aspects of these chromoproteins.

A study of the isolated subunits of B-phycoerythrin as well as the native biliprotein itself provides further support to the conclusion that phycoerythrobilin is the only chromophore in B-phycoerythrin.

1. The effect of the mercurial, p-chloromercuribenzoate (PCMB), upon phycoerythrin isolated from Ceramium rubrum has been studied. 2. Gel filtration permitted the separation of 4 types of subunit from the mercurial-treated phycoerythrin. The first, an insoluble protein, exhibited a major absorption maximum at about 500 mμ and a subsidiary band at about 550 mμ. The second, a soluble protein, exhibited 2 absorption maxima at 500 and 545 mμ. The third and fourth are also soluble and absorb at 493 and 495 mμ, respectively. The fourth protein is thought to be a soluble form of the insoluble protein since it also exhibits an absorption band around 550 mμ. 3. Removal of the mercurial from the unfractionated subunits with glutathione did not bring about complete reconstitution of the native phycoerythrin. However, the second subunit was found to undergo considerable reassociation. 4. The reassociated form of the second subunit exhibited a high degree of regeneration of the 565 mμ absorption band suggesting a specific relationship between the 565 mμ chromophore and protein conformation.

Phycoerythrin, pigment-protein complex in photosynthetic organisms, plays a role in photosynthesis in transferring an energy abosrbed by itself to chlorophyll. Previous studies in this laboratory showed that the longest absorption band at 565 millimicrons responsible for fluorescence originates from the interaction between the pigment and SH-group of the protein in phycoerythrin. During the course of investigation on the effect of SH-blocking agent on energy transfer, it was found that modified phycoerythrin is released from cells treated with PCMB. This modified phycoerythrin possesses a single absorption band at 545 millimicrons, while native phycoerythrin shows three absorption bands at 500, 545, and 565 millimicrons. In the glutathione-treated modified phycoerythrin, the highly fluorescent 565 millimicrons chromophore was partially regenerated. This investigation indicates that native phycoerythrin is composed of two units and that modified phycoerythrin is one of them separated from the other containing the 500 millimicrons chromophore only. (Author)

— Carotenoid pigments were extracted and purified from wild-type and mutants 7 and 93a of Sarcina lutea, and tested for their ability to quench 1O2. The wild-type pigment (P-438, 9 conjugated double bonds) is as active in quenching 1O2 as is β-carotene. On the other hand, the pigment P-422 (8 conjugated double bonds) from mutant 7 is 2 or 3 times less efficient, whereas phytofluene and phytoene from S. lutea are 100 and 1000 times less efficient, respectively, than is β-carotene at quenching 1O2. It was also found that the broad EPR signal, induced by light in benzene solutions of chlorophyll a and hydroquinone, and related to chlorophyll oxidation, is efficiently quenched by P-438 and to a much smaller extent also by Sarcina phytoene.

1. Spectral changes of Rhodospirillum rubrum chromatophores and subchromatophores at low pH have been investigated both in the absence and presence of the nonionic detergent, Triton X-100. 2. Bchl 800 readily undergoes pheophytinization below pH 3, whereas Bchl 880 is not easily converted to bacteriopheophytin until Triton X-100 is added. 3. In appropriate concentrations of Triton X-100, Bchl 880 is transformed to Bph 755 via some intermediates absorbing at 770–790 nm. The Bph 755 is subsequently converted to Bph 850. 4. These changes are more clearly observed with subchromatophores at different pH values. When subchromatophore particles reaggregate upon removal of Triton X-100, Bchl 880 again becomes resistant to acid treatment. 5. Treatment of chromatophores with Triton X-100 at low pH also causes a considerable decrease of absorbance in the wavelength region where carotenoids absorb. 6. The disintegrating action of Triton X-100 is enhanced by lowering pH, and a carotenoid complex can be separated from a heavier bacteriopheophytin complex.

1. 1.The spectral and sedimentation characteristics of phycoerythrin isolated from both fresh and aged blue-green algae of the genus Hydrocoleum have been investigated as well as the effect of organic mercurials upon their absorption spectra and association states. 2. 2.Phycoerythrin from fresh algae exhibits a single absorption maximum at 560 mμ and consists of three (5.7, 10.5, and 18.0 S) species, whereas phycoerythrin from aged algae exhibits two absorption maxima at 542 and 567 mμ and consists chiefly of a single 2.9 S species. 3. 3.Dissociation of only phycoerythrin obtained from fresh algae is effected by organic mercurials and partial reassociation occurs with mercaptoethanol. 4. 4.Organic mercurials effect a change in the spectral characteristics of both forms of phycoerythrin, however, subsequent addition of mercaptoethanol brings about a partial repair of these changes. 5. 5.These spectral changes as well as dissociation-association aspects are discussed in terms of conformational alteration in pigment-protein and protein protein interactions involved in the phycoerythrin molecule.

Phycoerythrin from Porphyridium cruentum (S20,w0= 11.5S) exhibits three visible absorption bands at 500, 545, and 565 mμ and is split by p-chloromercuribenzoate into two types of subunit which are easily separated by either centrifugation or gel filtration. One of the subunits is insoluble and exhibits a major absorption maximum at 500 mμ. The other soluble subunit (S20,w0 = 2.3S) exhibits a single absorption maximum at 545 mμ. The 565-mμ band disappears as a result of this treatment. Native phycoerythrin is not completely reconstituted from the unseparated subunits upon removal of the p-chloromercuribenzoate through the addition of mercaptoethanol or glutathione. Aggregation among the soluble subunits occurs to some extent producing an associated form exhibiting a better regeneration of the 565-mμ absorption band than does the unassociated form.

The action and emission spectra of the delayed light emission from Chlorella, Nostoc, and spinach chloroplasts have been measured. The action spectra for Chlorella and for spinach chloroplasts are quite similar to the absorption spectra of these materials. The action spectrum for Nostoc, on the other hand, shows a relatively low activity for chlorophyll and carotenoids and a high activity for phycocyanin. The emission spectra of these materials demonstrates that the luminescence is the result of a transition between the first excited singlet state and the ground state of chlorophyll. Low-temperature studies suggest that the triplet state of chlorophyll is not involved at all in the luminescence of spinach chloroplasts. There is some indication that part of the light emitted from Nostoc is due to a phycocyanin transition.