Bromine, Bromophenols and Floridorubin in the Red Alga Lenormandia prolifera

The pigment floridorunin was localized to the cuticle of the red alga Lenormandia prolifera (C. Ag.) J. Agardh by x-ray micro-analysis in Ihe transmission electron microscope and by its colour reactions in the light microscope. The pigment was set free from the cell wall by a pectinase. Bromine was also identified in the chloro-plasts. the middle lamellae, the intercellulars and the pore plugs of the alga. The content of bromophenols in the alga increases with increasing age. The cell walls of old plants are stratified and their outer parts are apparently shed. The bromophenols could have a function as regulators of the epiphytes or the shedding of parts of the outer cell wall.     

Subtle effects of biological invasions: cellular and physiological responses of fish eating the exotic pest Caulerpa racemosa

The green alga Caulerpa racemosa var. cylindracea has invaded Mediterranean seabed including marine reserves, modifying the structure of habitats and altering the distributional patterns of associated organisms. However, the understanding of how such invasion can potentially affect functional properties of Mediterranean subtidal systems is yet to be determined. In this study, we show that C. racemosa changes foraging habit of the native white seabream, Diplodus sargus. In invaded areas, we found a high frequency of occurrence of C. racemosa in the stomach contents of this omnivorous fish (72.7 and 85.7%), while the alga was not detected in fish from a control area. We also found a significant accumulation of caulerpin, one of the main secondary metabolites of C. racemosa, in fish tissues. The level of caulerpin in fish tissues was used here as an indicator of the trophic exposure to the invasive pest and related with observed cellular and physiological alterations. Such effects included activation of some enzymatic pathways (catalase, glutathione peroxidases, glutathione S-transferases, total glutathione and the total oxyradical scavenging capacity, 7-ethoxy resorufin O-deethylase), the inhibition of others (acetylcholinesterase and acylCoA oxidase), an increase of hepatosomatic index and decrease of gonadosomatic index. The observed alterations might lead to a detrimental health status and altered behaviours, potentially preventing the reproductive success of fish populations. Results of this study revealed that the entering of alien species in subtidal systems can alter trophic webs and can represent an important, indirect mechanism which might contribute to influence fluctuations of fish stocks and, also, the effectiveness of protection regimes.     

Two novel aromatic valerenane-type sesquiterpenes from the Chinese green alga Caulerpa taxifolia

Caulerpal A (2) and B (3), two novel sesquiterpenes possessing an uncommon aromatic valerenane-type carbon skeleton, along with one known metabolite, caulerpin (4), have been isolated from the Chinese green alga Caulerpa taxifolia (Vahl) C. Agardh. Their structures and relative stereochemistry were elucidated on the basis of extensive spectroscopic analysis. Compounds 2-4 were evaluated for their inhibitory activity against hPTP1B and the result showed that only compound 4 had a strong PTP1B inhibitory activity with an IC50 value of 3.77 microM.     

Synchroma grande spec. nov. (Synchromophyceae class. nov., Heterokontophyta): an amoeboid marine alga with unique plastid complexes

Chromist algae including the Heterokontophyta are supposed to have evolved monophyletically by secondary endosymbiosis from a eukaryotic host cell that engulfed a eukaryotic red alga. The red algal endosymbiont was then reduced to a secondary plastid surrounded by four enveloping membranes. On the basis of the amoeboid marine alga Synchroma grande gen. et spec. nov., the Synchromophyceae are described here as a new class of Heterokontophyta. Their taxonomic position is characterized by 18S rRNA and rbcL gene phylogenies, morphology, and pigment composition. The so far unique feature of the Synchromophyceae is the occurrence of conspicuous chloroplast complexes representing multiplastidic red secondary endosymbionts. In these remarkable secondary endosymbionts, several primary chloroplasts are aggregated in a common periplastidial compartment and are collectively enveloped by an additional outer membrane pair. The discovery of this novel plastid morphology is highly relevant for research on algal evolution and is discussed in terms of the postulated monophyletic origin of Chromista.     

Blue-light-induced chloroplast orientation in Mougeotia. Evidence for a separate sensor pigment besides phytochrome

Chloroplast orientation in the green alga Mougeotia has been induced by unidirectional red or blue light, given continuously during one hour. In addition, part of the preparations obtained scattered strong far-red light simultaneously with the orienting light. This far-red light completely abolished the response to red light, consistent with phytochrome as the sensor pigment for orientation in Mougeotia. In blue light, however, the response was completely insensitive to far-red light, thus pointing to a different sensor pigment in the shortwavelength region.Abbreviation P_fr far-red-absorbing form of phytochrome     

Biofilm-specific cross-species induction of antimicrobial compounds in bacilli

An air-membrane surface (AMS) bioreactor was designed to allow bacteria to grow attached to a surface as a biofilm in contact with air. When Bacillus licheniformis strain EI-34-6, isolated from the surface of a marine alga, was grown in this reactor, cells produced antimicrobial compounds which they did not produce when they were grown in shake flask cultures. An unidentified red pigment was also produced by surface-grown cells but not by planktonically grown cells. Glycerol and ferric iron were important for the production of antimicrobial compounds and the red pigment. Release of these secondary metabolites was not due to the onset of sporulation. Cell-free spent medium recovered from beneath the reactor membrane could induce production of antimicrobial compounds and red pigment in shake flask cultures. Neither glycerol nor ferric iron was required for production of these inducer compounds. Spent medium from beneath the membrane of an AMS bioreactor culture of Bacillus subtilis strain DSM10(T) and Bacillus pumilus strain EI-25-8 could also induce production of antimicrobial compounds and a red pigment in B. licheniformis isolate EI-34-6 grown in shake flask cultures; however, the corresponding spent medium from shake flask cultures of DSM10(T) and EI-25-8 could not. These results suggest that there is a biofilm-specific cross-species signaling system which can induce planktonically grown cells to behave as if they were in a biofilm by regulating the expression of pigments and antimicrobial compounds.     

Isolation and characterization of biliprotein aggregates from Acaryochloris marina, a Prochloron-like prokaryote containing mainly chlorophyll d

Phycobiliprotein aggregates were isolated from the prokaryote Acaryochloris marina, containing chlorophyll d as major pigment. In the electron microscope the biliprotein aggregates appear as rod-shaped structures of 26.0×11.3 nm, composed of four ring-shaped subunits 5.8 nm thick and 11.7 nm in diameter. Spectral data indicate that the aggregates contain two types of biliproteins: phycocyanin and an allophycocyanin-type pigment, with very efficient energy transfer from the phycocyanin- to allophycocyanin-type constituent. The chromophore-binding polypeptides of the pigments have apparent molecular masses of 16.2 and 17.4 kDa. They crossreact with antibodies against phycocyanin and allophycocyanin from a red alga.     

Isolation of phytochrome from the alga mesotaenium and liverwort sphaerocarpos

Phytochrome has been isolated from the green alga Mesotaenium and the liverwort Sphaerocarpos. The Mesotaenium pigment had absorption peaks at 649 and 710 nm for the P_R and P_FR forms, respectively. Corresponding difference spectrum maxima for the Sphaerocarpos pigment were at 655 and 720 nm. While the absorption maxima differ, the reversibility and efficiency with which red and far-red light transform the Mesotaenium pigment are very similar to that reported for phytochrome isolated from etiolated seedlings of higher plants. Methods are described which allow efficient separation of phytochrome from highly pigmented light-grown material.     

Biofilm-Specific Cross-Species Induction of Antimicrobial Compounds in Bacilli

An air-membrane surface (AMS) bioreactor was designed to allow bacteria to grow attached to a surface as a biofilm in contact with air. When Bacillus licheniformis strain EI-34-6, isolated from the surface of a marine alga, was grown in this reactor, cells produced antimicrobial compounds which they did not produce when they were grown in shake flask cultures. An unidentified red pigment was also produced by surface-grown cells but not by planktonically grown cells. Glycerol and ferric iron were important for the production of antimicrobial compounds and the red pigment. Release of these secondary metabolites was not due to the onset of sporulation. Cell-free spent medium recovered from beneath the reactor membrane could induce production of antimicrobial compounds and red pigment in shake flask cultures. Neither glycerol nor ferric iron was required for production of these inducer compounds. Spent medium from beneath the membrane of an AMS bioreactor culture of Bacillus subtilis strain DSM10^T and Bacillus pumilus strain EI-25-8 could also induce production of antimicrobial compounds and a red pigment in B. licheniformis isolate EI-34-6 grown in shake flask cultures; however, the corresponding spent medium from shake flask cultures of DSM10^T and EI-25-8 could not. These results suggest that there is a biofilm-specific cross-species signaling system which can induce planktonically grown cells to behave as if they were in a biofilm by regulating the expression of pigments and antimicrobial compounds.     

Bromo-compounds of the red alga Lenormandia prolifera

Six bromo-compounds and one bromo-chloro-compound have been detected in Lenormandia prolifera (C.Ag.) J. Agardh (Amansieae; Rhodomelaceae). Hydrolysis of the red pigment floridorubin from the same alga yielded five bromo-, one bromo-chloro and one chloro-phenol. The two main phenols of floridorubin were 2,3-dibromo-4,5-dihydroxy benzyl alcohol (lanosol) and 3,5-dibromo-p-hydroxybenzyl alcohol.     

The P450-type carotene hydroxylase PuCHY1 from Porphyra suggests the evolution of carotenoid metabolism in red algae

Carotene hydroxylases catalyze the hydroxylation of a-and b-carotene hydrocarbons into xanthophylls. In red algae, b-carotene is a ubiquitously distributed carotenoid, and hydroxylated carotenoids such...     

Chromatic adaptation and photoreversal in blue-green algaCalothrix clavata West

Complementary chromatic adaptation, a well-established phenomenon in some blue-green algae, has been observed inCalothrix clavata, a heterocystous blue-green alga of the family Rivulariaceae. The chromatic adaptation has been observed for fluorescent and incandescent light by measuring the absorption spectra. The material grown in fluorescent light forms more of phycoerythrin whereas more of phycocyanin tends to be formed in incandescent light. Besides this, photoreversal was observed by transferring the incandescent light grown alga to fluorescent light conditions and vice-versa. Effect of photoreversal and chromatic adaptation has also been discussed for this alga under different monochromatic light conditions. The influence of different light conditions on morphological changes, heterocysts and hormogonia formation has also been investigated. Both chromatic adaptation and photomorphogentic phenolmena in this alga show the involvement of some photoreversible (red:green) pigment.     

CHLOROPLAST STRUCTURE AND PIGMENT COMPOSITION IN THE RED ALGA GRIFFITHSIA PACIFICA: REGULATION BY LIGHT INTENSITY1

The ratio of accessory phycobiliproteins to chlorophyll a is controlled by light intensity in the marine red alga Griffithsia pacifica. The greatest changes in pigment ratios are observed below 300 ft-c; above 300 ft-c the response approaches saturation. Ultrastructural examination of chloroplasts of plants grown at different intensities reveals that the number of phycobilisomes per unit of photosynthetic thylakoid changes in direct proportion to the pigment ratios and in inverse proportion to the light intensity.     

Purification and Characterization of a New Pigment from the Green Alga, Bryopsis maxima

Several, new, water-soluble pigments have been detected in thematured thalli of the green alga, Bryopsis maxima. Among thepigments, a major red one has been purified and characterized.The red pigment has absorption maxima at 237, 268, 331, 450,485 and 520 nm and a shoulder at 570 nm. Its fluorescence emissionspectrum has maxima at 659 and 730 nm. The pigment has minuscharge at the pH above 3.0 and is soluble in water and polarorganic solvents but not in nonpolar solvents. Its molecularweight was estimated to be 1,490. The infrared, N.m.r. and massspectra suggest that the pigment has an open tetra pyrrole structure. ⁵Present address: Department of Biochemistry, Nippon MedicalSchool, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113, Japan. (Received July 2, 1987; Accepted August 26, 1987)     

Modular antenna of photosystem I in secondary plastids of red algal origin: a <Emphasis Type="Italic">Nannochloropsis oceanica</Emphasis> case study

Photosystem I (PSI) is a multi-subunit integral pigment–protein complex that performs light-driven electron transfer from plastocyanin to ferredoxin in the thylakoid membrane of oxygenic photoautotrophs. In order to achieve the optimal photosynthetic performance under ambient irradiance, the absorption cross section of PSI is extended by means of peripheral antenna complexes. In eukaryotes, this role is played mostly by the pigment–protein complexes of the LHC family. The structure of the PSI-antenna supercomplexes has been relatively well understood in organisms harboring the primary plastid: red algae, green algae and plants. The secondary endosymbiotic algae, despite their major ecological importance, have so far received less attention. Here we report a detailed structural analysis of the antenna-PSI association in the stramenopile alga Nannochloropsis oceanica (Eustigmatophyceae). Several types of PSI-antenna assemblies are identified allowing for identification of antenna docking sites on the PSI core. Instances of departure of the stramenopile system from the red algal model of PSI-Lhcr structure are recorded, and evolutionary implications of these observations are discussed.     

Light-Harvesting System of the Red Alga Gracilaria tikvahiae: I. Biochemical Analyses of Pigment Mutations

Wild type Gracilaria tikvahiae, a macrophytic red alga, and fourteen genetically characterized pigment mutants were analyzed for their biliprotein and chlorophyll contents. The same three biliproteins, phycoerythrin, phycocyanin, and allophycocyanin, which are found in the wild type are found in all the Mendelian and non-Mendelian mutants examined. Some mutants overproduce R-phycoerythrin while others possess only traces of phycobiliprotein; however, no phycoerythrin minus mutants were found. Two of the mutants are unique; one overproduces phycocyanin relative to allophycocyanin while the nuclear mutant obr synthesizes a phycoerythrin which is spectroscopically distinct from the R-phycoerythrin of the wild type. The phycoerythrin of obr lacks the typical absorption peak at 545 nanometers characteristic of R-phycoerythrin and possesses a phycoerythrobilin to phycourobilin chromophore ratio of 2.6 in contrast to a ratio of 4.2 found in the wild type. Such a lesion provides evidence for the role of nuclear genes in phycoerythrin synthesis. In addition, comparisons are made of the pigment compositions of the Gracilaria strains with those of Neoagardhiella bailyei, a macrophytic red alga which has a high phycoerythrin content, and Anacystis nidulans, a cyanobacterium which lacks phycoerythrin. The mutants described here should prove useful in the study of the genetic control of phycobiliprotein synthesis and phycobilisome structure and assembly.     

Action Spectra for Chromatic Adaptation in Tolypothrix tenuis

The dark synthesis of biliproteins in the blue-green alga Tolypothrix tenuis is controlled by brief light treatments. Green light potentiates synthesis of phycoerythrin and red light potentiates synthesis of phycocyanin. Red reverses the effect of green and vice versa. Action spectra for the red and green effects were obtained for the wavelength region 320 nanometers to 710 nanometers, at 10-nanometer intervals. The principal action band in the red peaks at 660 nanometers, with a half-band width of 58 nanometers and an accompanying shortwave band at 360 nanometers. The green action band peaks at 550 nanometers, with a half-band width of 76 nanometers, and a shortwave band at 350 nanometers. Chromatic adaptation and another photomorphogenic response in the blue-green algae are discussed in terms of possible regulation by a photoreversible pigment recently isolated from Tolypothrix.     

A red alga‐specific phycoerythrin gene for biodiversity surveys of callithamnioid red algae

We introduce a photosynthetic pigment‐encoding phycoerythrin gene, consisting of alpha (cpeA) and beta (cpeB) units that can be used for biodiversity surveys of callithamnioid red algae. A set of polymerase chain reaction (PCR) primers were designed to amplify an approximately 1‐kb fragment of the gene from 14 taxa. These have been proven useful in isolating the gene from samples mixed with diatoms. Pairwise distance and synonymous and nonsynonymous nucleotide substitution rates of the cpeA and cpeB regions are described. This is the first study to examine the phycoerythrin sequences for use in red alga biodiversity surveys.     

Effect of light source for growth on photosynthetic reactions of Anabaena variabilis particles

Photosynthetic particles were prepared from the blue—green alga Anabaena variabilis grown under two different light conditions. Photosynthetic activity of particles from fluorescent-light-grown cells was lower than that of particles from tungsten-grown cells. The photosynthetic activities of particles from fluorescent-light-grown cells could be increased by moving these cultures to tungsten light. The extent of recovery depended on the ratio of fluorescent growth to the tungsten growth period. It was concluded that the difference in photosynthetic activities between tungsten and fluorescent grown cell-free preparations is more likely due to a lack of red light rather than to disturbance of pigment contents.     

Phycochrome d, a New Photochromic Pigment from the Blue-Green Alga, Tolypothrix distorta

A new reversibly photochromic pigment, phycochrome d, has been found in extracts of the blue-green alga Tolypothrix distorta. This phycochrome exhibits an absorbance increase in the red region (maximum at about 650 nm) when irradiated with 650 nm light, and a corresponding absorbance decrease when irradiated with 610 nm light. The absorbance difference spectrum and action spectra for in vitro conversions were determined.