Porphyra Umbilicalis Research Articles

Changes in photosynthetic pigment concentration in seaweeds as a function of water depth

We conducted a study of the relationship between changes in photosynthetic pigment content and water depth in Great Harbor near Woods Hole, Massachusetts, USA, on the green algae Ulva lactuca and Codium fragile and the red algae Porphyra umbilicalis and Chondrus crispus. A calibrated underwater photometer equipped with spectral band filters measured light attenuation by the water column. The depth required for a 10-fold diminution of photon flux was 3.6, 5.3, 6.0 and 6.0 m for red, blue, yellow and green light, respectively. Seaweeds were attached to vertically buoyed lines and left to adapt for 7 days; then, with their positions reversed, they were allowed to readapt for 7 days. All species showed greater photosynthetic pigment content with increased depth. Further, the ratio of phycobiliproteins and chlorophyll b to chlorophyll a increased with depth. Changes in pigment content were reversible and occurred in the absence of cell division. There was a net loss of pigments near the surface (high irradiance), and subsequent synthesis when seaweeds were transferred to a position deep in the water column (low irradiance). In contrast, seaweeds which were found in intertidal habitats changed only their pigment concentration, and not pigment ratio, a phenomena analogous to higher plant sun and shade adaptation. Therefore, seaweeds modify their photon-gathering photosynthetic antennae to ambient light fields in the water column by both intensity adaptation and complementary chromatic adaptation.

Cytochrome cs from Rhodymenia palmata and Porphyra umbilicalis and the amino acid sequences of their N-terminal regions

Basic c-type cytochromes homologous with plant and animal mitochondrial cytochrome c have been isolated and purified from Rhodymenia palmata and Porphyra umbilicalis. The N-terminal regions have been analysed using a Beckman 890C automatic sequencer. When compared to animal cytochrome c, the Rhodymenia cytochrome c has an unblocked N-terminal tail of 10 amino acids, whereas Porphyra has an unblocked N-terminal tail of only a single amino acid.

STUDIES ON THE ALGAL CUTICLE(1).

A chemically resistant cuticle fraction was isolated from 5 phaeophycean, 1 rhodophycean, and 11 chlorophycean marine algae using acid treatment alone, or acid treatment followed by leaching in cupra-ammonium. In Cladophora rupestris and Chaetomorpha melagonium this fraction consists of several alternate microfibrillar and amorphous layers similar in appearance to those seen in innermost carbohydrate-rich regions and amount to about 1/10 or more of the cell wall thickness. In Porphyra umbilicalis and Padina vickersiae it is a single layer less than I μ thick, accounting for 1/50-1/100 of the cell wall in Porphyra, and 1/5-1/10 of the cell wall in Padina. The cuticle fractions of all 4 algae contain surprisingly large amounts of protein (about 70% in Cladophora and 80% in Porphyra). Similarities in the behavior of cuticles obtained from the other 12 species studied suggest that they may have a similar protein-rich composition.

Some neutral constituents of the Rhodophyceae with special reference to the occurrence of the floridosides

Isofloridoside, in addition to floridoside, was demonstrated as a constituent of 16 species of the Bangiophycidae and Florideophycidae (Rhodophyceae). Photosynthetic experiments with Porphyra umbilicalis resulted in a very slow labelling of isofloridoside both in light and in darkness after photosynthesis in 14CO2. This observation supports the concept that the floridosides are not equivalent as metabolites.Trehalose was identified as a constituent of species of the Corallinaceae. A dideoxyinositol, D-(+)-14/25-cyclohexanetetrol, was isolated from Porphyridium sp., taurine from Polyides rotundus, and di-N-methyl taurine was obtained from Corallina officinalis.

Uptake of plutonium by the lobster Homaris vulgaris.

BECAUSE of its long effective half-life and its decay characteristics, and since it is deposited in bone, man-made plutonium is one of the more hazardous of the radio-elements. It is released in exceedingly small amounts from nuclear fuel reprocessing plants and in nuclear weapons tests, and, like the long-lived fission products evolved in this way, it may be detected at low concentrations in the marine environment. The concentration of plutonium by marine organisms is, therefore, of some interest. The total a-content of the edible seaweed Porphyra umbilicalis and of fillets of the plaice Pleuronectes platessa, collected near Windscale Works, are given by Dunster et al.1. Some data on the contemporary plutonium content of Pacific Ocean sea water and the concentration factors in certain marine plants and animals collected near the southern California coast are given by Pillai et al.2. The concentration factor is the ratio of the amount of plutonium per g of tissue (wet weight) to the plutonium in the same weight of sea water.

Autecological studies of the genusPorphyra

The type of Porphyra umbilicalis (L.) J. Ag. is recognised and the species may be regarded as widespread and adaptable. In Britain, three distinct forms can be marked out but these appear to be res...

THE CONCENTRATION OF NUCLEIC ACIDS IN SOME COMMON MARINE ALGAE

The method of Smillie and Krotkov has been applied to the estimation of soluble ribonucleic acid and deoxyribonucleic acid in nine species of marine algae, representative of the Chlorophyceae, Rhodophyceae, and Phaeophyceae. Treatment of the extract with an anion exchange resin was essential for the determination of RNA. Values for RNA and DNA, expressed as percentages of total solids, were respectively as follows: Ulva lactuca 0.63 and 0.10, Chondrus crispus 0.91 and 0.65, Rhodymenia palmata 0.73 and 0.41, Porphyra umbilicalis 1.62 and 0.19, Furcellaria fastigiata 0.37 and 0.36, Laminaria longicruris 0.68 and 0.06, L. digitata 0.67 and 0.30, L. agardhii 0.90 and 0.07, Fucus vesiculosus 0.29 and 0.05, based on commercial nucleic acids assayed by ultraviolet absorption, as standards. Use of ribose and deoxyribose as standards gave lower results. Attempts to prepare pure polynucleotides from several marine algae were unsuccessful.

ZN65 UPTAKE BY BENTHIC MARINE ALGAE1

The effects of various environmental factors on Zn65 uptake and loss were investigated in benthic algae. Increasing the pH promoted Zn65 uptake and retarded Zn65 loss in Ulva lactuca, Porphyra umbilicalis, and Laminaria agardi. A similar pH dependency was displayed by killed algae of the same species which in all cases absorbed more Zn65 than the live seaweed. The addition of carrier zinc to natural sea‐water wash solutions had little effect on the rate of Zn65 loss from radioactive algae. Increasing the temperature of the wash resulted in a slight increase in the rate of Zn65 loss. Polarographic determinations of the natural zinc content of algae were made. Fucus had the highest zinc concentration, 829 mg/kg dry wt, while Porphyra showed the lowest, 123 mg/kg.Exposure to light stimulated both the uptake and loss of Zn65. Uptake was retarded by two inhibitors, uranyl nitrate and phenylurethane. The biological half‐life of Zn65 in algae in the light and in the dark was estimated. Fucus showed a much higher retention of Zn65 than either Porphyra or Ulva. The effects of photosynthesis‐related pH changes on both metabolic and non‐metabolic uptake mechanisms are considered.

Carbohydrase and sulphatase activities of Porphyra umbilicalis.

Carbohydrase and sulphatase activities of Porphyra umbilicalis.

Isolation of L-Galactose-6-sulphate from a Seaweed Polysaccharide

SULPHATED polysaccharides occur widely as major components of many seaweeds1. Until now, however, locating the sulphate hemi-ester groups in the polysaccharide structure has rested upon evidence from methylation data2,3, supported in some cases by infra-red spectroscopy4,5. Here we report the application of the method of partial acidic hydrolysis to determine the position of sulphate residues in porphyran, the mucilage of the red seaweed Porphyra umbilicalis

Studies in the Bangioideae. 2. The Conchocelis-phase of Porphyra sp. in Pollicipes cornucopia Leach at Roscoff.

The occurrence of the Conchocelis-phase of a species of Porphyra in the peduncular scales of the barnacle, Pollicipes cornucopia at Roscoff, France, is recorded. This Conchocelis-growtb. closely resembles that described by Batters as G. rosea, the only species in the genus created by him. It is also identical with growths of Gonchocelis originating from spores of Porphyra umbilicalis (L.) Kiitz. in culture. A study of the fertile cell rows occurring in the peduncular scales of P. cornucopia suggests that, by the breakdown of the transverse walls, tubes are formed and that the spores pass along these to the surface of the scales and are there liberated into the sea. The ecological importance of the Gonchocelis-phase in the life history of Porphyra is stressed.

641. The structure of the mannan present in Porphyra umbilicalis

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核型の系統, 特に生物の起原に關連して

The phylogeny of karyotypes was investigated in lower plants i. e., flagellata, algae and fungi. The most primitive plants, bacteria and Cyanophyceae have no nuclei in strict sense and no chromosomes. The nuclei of Protozoa such as Vorticella and Stentor suggest the origin of chromosomes (Fig. 2). The most primitive nucleus seems to have two chromosomes in haploid number. A large number of fungi has lower chromosome number and especially Ascomycetes and Basidiomycetes have two chromosomes in haploid number, while on the other hand, most algae have high chromosome number, especially Charophyta has many chromosomes, namely, from twelve to ca. 50 chromosomes in haploid number (of. Tab. 1). The most primitive type of Rhodophyceae, Bangia fusco-purpurea and Porphyra umbilicalis have also two chromosomes in haploid number and the other algae have higher chromosome number.There are three modes of metabolism, namely heterotrophic one assimilating organic substance and autotrophic metabolism of which one assimilates inorganic substance by means of photosynthesis and the other assimilates by chemosynthesis. Osborn and Komarov supported that the chemo-autotrophic metabolism was most primitive, while Oparin suggests the most primitive organism assimilates organic substance which is abundantly produced in such environment, and inorganic substance such as oxygen and carbon dioxide seems to occur more rarely than in present. If this opinion is true, the heterotrophic organism such as fungi may be more primitive than autotrophic one such as algae in the mode of metabolism. Such primitive condition is also observed in karyotype phylogeny (Tab. 1). In short, the parallelism between the mode of metabolism and karyotype phylogeny was clearly demonstrated in fungi and algae.

STUDIES ON THE PHOTOSYNTHESIS OF MARINE ALGAE NO.1: PHOTOSYNTHETIC RATES OF ENTEROMORPHA LINZA, PORPHYRA UMBILICALIS AND DELESSERIA SINUOSA IN RED, GREEN AND BLUE LIGHT

Pieces of the fronds of Enteromorpha linza, a green alga, growing just beneath the surface of the sea, of Porphyra umbilicalis, a red alga, of which the fronds of brownish-red colour which were growing on the side of a dock at half-tide level were selected, and of Delesseria sinuosa, a bright magenta-red alga from a depth of 18 metres in Passamaquoddy bay, were placed in vials of sea water (previously brought to pH 7 by the addition of KH2PO4), behind Corning red, green and blue filters, which had been brought to equal intensity in the photosynthetically active part of the spectrum, and exposed to sunshine. The gain in pH, due to the using up of CO2, was read at the end of 10 minute periods with a B.D.H. capillator set, and the photosynthetic rates for each species were determined by dividing the gain in pH (in hundredths of a unit) by the time. The photosynthetic rates of these three species in the different regions of the spectrum were very different, those of E. linza being red = 1.80; green = 0.16 and blue = 1.16, of P. umbilicalis red = 2.46; green and blue = 1.65, and of D. sinuosa red = 1.35; green = 1.25 and blue = 1.05. These data fit in very well with the transmission coefficients for red, green and blue light in the bay of Fundy at the place where the experiments were carried on, as green light penetrates best, blue next and red least.