Bryopsis Plumosa Research Articles

Characterization of the Peroxidase Activity of Single Algae Protoplasts by Scanning Electrochemical Microscopy

Abstract The peroxidase activity in a single protoplast of alga Bryopsis plumosa is quantitatively characterized by scanning electrochemical microscopy. The generation of ferriceniummethanol (FMA+) at the protoplast surface is directly detected by the microelectrode tip scanned close to the sample surface in seawater containing ferrocenemethanol (FMA) and hydrogen peroxide, an electron mediator and an enzyme-substrate, respectively. The oxidation reaction requires hydrogen peroxide, which clearly shows FMA+ generation due to the peroxidase (POD) catalytic reaction occurring in the protoplast. The FMA+ generation and the FMA accumulation rates at a single alga protoplast were equivalent. A plot of the FMA+ generation rates according to the hydrogen peroxide concentrations was well allowed with a Michaelis–Menten-type reaction. An estimation of the mass-transfer rate and a determination of the Km are quite important advantages of the SECM technique that cannot be realized using other techniques. The POD activity has been further investigated from the viewpoint of the size of the protoplast. The POD activity of the alga in the adult stage is also visualized by SECM. The noninvasive nature of the SECM technique has been confirmed by observing the developmental process after measurements.

Transient existence of life without a cell membrane: a novel strategy of siphonous seaweed for survival and propagation.

Siphonous seaweeds, which constitute a vital component of coral reefs, are structurally simple, single-celled coenocytic macroscopic green algae. Kim et al.1 have recently shown the extraordinary wound-repair and propagation mechanism of one such siphonous green alga--Bryopsis plumosa. Nucleocytoplasmic aggregates, which are released after injury to this plant, are membraneless structures that can survive in seawater for 10-20 minutes, before they are surrounded by a gelatinous envelope. Subsequently, a cell membrane and cell wall are synthesized around each of these aggregates and the resulting individual cells, so formed, develop into new plants. This report represents a significant advance in our understanding of wound response and, more significantly, is probably the first example of transient survival of life without a cell membrane!

Life without a cell membrane: regeneration of protoplasts from disintegrated cells of the marine green alga Bryopsis plumosa.

When the multi-nucleate giant cells of the green alga Bryopsis plumosa (Huds.) Ag. are injured, the protoplasm is extruded from the cells and can generate spontaneously numerous new cells. The cell organelles aggregate rapidly in seawater and become covered with a gelatinous envelope within 15 minutes. A lipid cell membrane is formed inside the envelope within 9 to 12 hours and about 15% of the original cell membrane is recycled to make the membrane of new protoplasts. Cytochemical studies using Nile Red and various enzymes revealed that the primary envelope is initially composed of polysaccharides, and then transformed into a polysaccharide-lipid complex. Fluorescein diacetate staining showed that the primary envelope has some characteristics of a cell membrane including semi-permeability and selective transport of materials. The aggregation of cell organelles appears to be mediated by two kinds of materials, one present in vacuolar sap and the other on the surface of the cell organelles. About a thousand new cells were generated from a single disintegrated branch and 40% of them eventually developed into mature plants.

REGENERATION OF PROTOPLASTS FROM DISINTEGRATED CELLS OF BRYOPSIS PLUMOSA (DERBESIALES, CHLOROPHYTA)

When injured, the protoplasms come out from the multi‐nucleate giant cell of a green alga Bryopsis plumosa and can generate numerous new cells spontaneously. The cell organelles aggregated rapidly in sea water and became covered with a gelatinous envelope within fifteen minutes. A lipid cell membrane was formed inside the envelope within nine to twelve hours. Cytochemical studies using Nile Red and various enzymes revealed that the primary envelope is initially composed of polysaccharides then becoming a polysaccharide‐lipid complex. Fluorescein diacetate (FDA) staining showed that the primary envelope has some characteristics of cell membranes including semipermeability and selective transport of materials. The aggregation of cell organelles appears to be mediated by two kinds of material; one in vacuolar sap and the other on the surface of cell organelles. About a thousand new cells were generated from a single disintegrated branch and forty percent of them eventually developed into mature plants.

GAMETE RELEASE IS INCREASED BY CALM CONDITIONS IN THE COENOCYTIC GREEN ALGA BRYOPSIS (CHLOROPHYTA).

Water motion did not inhibit gamete release in cultures of the coenocytic green alga Bryopsis plumosa (Hudson) C. Agardh; however, the number of gametangia that released gametes increased significantly under transiently calm conditions. This stimulatory effect of calm conditions in the laboratory was found in isolates from two different areas of the Maine coast. The isolates were all monoecious, but strong differences in levels of fertilization, numbers of male and female gametes remaining following fertilization, and levels of polygamy (=zygotes formed by fusions of more than two gametes) were observed among isolates. These data support the hypothesis that organisms with external fertilization are able to sense and respond to water motion in ways that favor reproductive success.

Microstructured TiO2 Templates for the Preparation of Size-ControlledBryopsis Protoplasts as Cell Models

Microstructured TiO2 films with hemispheric pores have been used here to control the size of protoplasts of the marine alga Bryopsis plumosa. The Figure shows protoplasts prepared on a 20 μm pitch TiO2 template, illustrating the small range of diameters that are obtained. This technique serves as a convenient way to provide cell models for in vitro physiological studies.

Heavy metal assessment in algae, sediments and water from the Bulgarian Black Sea coast

The aim of our investigation is a survey of heavy metal pollution in algae, sediments and water from the Bulgarian Black Sea coast and determination of algae species appropriate as bioindicators. The levels of iron, copper, manganese, zinc, lead and cadmium are determined in water, sediments and eight species of macroalgae: (four green: Cladofora laetevirens, Ulva rigida, Enteromorpha intestinalis and Bryopsis plumosa; two brown: Cystoseira crinita and Cystoseira barbata; and two red: Ceramium rubrum and Corallina mediterranium), widely distributed in the Bulgarian coastal zone, and dominant in the Black Sea. The studied area is the littoral coastal zone from four locations - Tuzlata, Ravda, Ahtopol and Sinemoretz. No significant variations between metal concentrations in algae samples are obtained, while for sediments and water there are significant differences between location and season. The Cladofora laetevirens and Ceramium rubrum species show the highest metal content while Cystoseira crinita and Cystoseira barbata show the lowest level. The correlation coefficients and concentration factors of the elements are calculated.

Heavy metal assessment in algae, sediments and water from the bulgarian black sea coast

The aim of our investigation is a survey of heavy metal pollution in algae, sediments and water from the Bulgarian Black Sea coast and determination of algae species appropriate as bioindicators. The levels of iron, copper, manganese, zinc, lead and cadmium are determined in water, sediments and eight species of macroalgae: (four green: Cladofora laetevirens, Ulva rigida, Enteromorpha intestinalis and Bryopsis plumosa; two brown: Cystoseira crinita and Cystoseira barbala; and two red: Ceramium rubrum and Corallina mediterranium), widely distributed in the Bulgarian coastal zone, and dominant in the Black Sea. The studied area is the littoral coastal zone from four locations - Tuzlata, Ravda, Ahtopol and Sinemoretz. No significant variations between metal concentrations in algae samples are obtained, while for sediments and water there are significant differences between location and season. The Cladofora laetevirens and Ceromium rubrum species show the highest metal content while Cystoseira crinita and Cystoseira barbta show the lowest level. The correlation coefficients and concentration factors of the elements are calculated.

Clorofíceas marinhas bentônicas da Praia de Serrambi, Pernambuco, Brasil

É apresentado o levantamento florístico sobre as clorofíceas marinhas bentônicas encontradas na Praia de Serrambi, litoral Sul do Estado de Pernambuco. O material estudado foi coletado em três estações, as quais foram visitadas mensalmente durante o período de abril de 1986 a setembro de 1987. As clorofíceas foram representadas na flora local por 39 espécies, três variedades e uma forma, pertencentes às ordens Ulotrichales, Ulvales, Siphonocladales, Cladophorales, Caulerpales e Dasycladales. Acetabularia calyculus Quoy & Gaimard. In Freycinet, Bryopsis pennata Lamouroux, Bryopsis plumosa (Hudson) C. Agardh, Caulerpa ambigua Okamura, Caulerpa serrulata (Forsskål) J. Agardh emend Børgesen, Chaetomorpha brachygona Harvey, Cladophora coelothrix Kützing, Cladophoropsis membranacea (C. Agardh) Børgesen, Codium intertextum Collins & Hervey, Ernodesmis verticillata (Kützing) Børgesen são novas referências para a flora do litoral de Pernambuco. Pringsheimiella scutata (Reinke) von Höhnel ex Marchewianka o é também para o litoral continental do Brasil. Halimeda opuntia (L.) Lamouroux foi hospedeira de maior número de epífitas, enquanto Bryopsis plumosa, quando epífita, foi a que cresceu sobre maior número de hospedeiros.

Gamete discharge by Bryopsis plumosa (Codiales, Chlorophyta) induced by blue and UV‐A light

SUMMARYGamete discharge by the coenocytic green alga Bryopsis plumosa (Hudson) C. Agardh is induced by light. The mature male gametangia consist of a mass of quiescent male gametes and a large central vacuole. Within a few minutes after the onset of irradiation, breakdown of the tonoplast of the central vacuole and initiation of gamete motility occur simultaneously. This is followed by a forced discharge of moving gametes through a hole ruptured at the subapical region of the gametangium. The action spectrum for the light‐induced gamete discharge was determined from a series of fluence‐response curves. This action spectrum, having two major maxima at 370 and 450 nm, indicates the involvement of a blue light/UV‐A‐absorbing photoreceptor previously described as ‘cryptochrome’.

Agglutinins from marine macroalgae of the southeastern United States

Protein extracts from 22 species of marine macroalgae from Florida and North Carolina were compared for their abilities to agglutinate sheep and rabbit erythrocytes. Protein extracts from 21 algal species agglutinated rabbit erythrocytes compared to 19 for sheep erythrocytes. However, agglutination by brown algal extracts was variable. The agglutination produced by protein extracts from Dictyota dichotoma could be blocked by addition of polyvinylpyrrolidone. Protein extracts from North Carolina macroalgae were also tested against five bacterial species. Three of these agglutinated bacterial cells. Ulva curvata and Bryopsis plumosa agglutinated all five species. Protein extracts from five species of Florida algae were tested for their effects on mitogenesis in mouse splenocytes and human lymphocytes. Gracilaria tikvahiae HBOI Strain G-5, Ulva rigida and Gracilaria verrucosa HBOI Strain G-16S stimulated mitogenesis in mouse splenocytes, while Gracilaria tikvahiae HBOI Strain G-16stimulated mitogenesis in human lymphocytes.

Chemical Constituents of the Caribbean Marine Alga Bryopsis plumosa

β-Sitosterol (24-ethyl-cholest-5-en-3β-ol) and a mixture of five fatty acids have been isolated from the green alga Bryopsis plumosa. The sterol was identified from its proton and carbon-13 NMR spectra and the fatty acids-tetradecanoic acid, hexadecanoic acid. 9- and 11-octadecenoic acids, and octadecanoic acid-were identified from a GC-MS of their methyl esters. The crude extract from B. plumosa demonstrated no activity in either an antimicrobial disk assay or a brine shrimp bioassay for cytotoxicity and was found to be an attractant for the predatory amphipods that were found living on the alga.

Radium and its Daughters in Bryopsis Plumosa

Radium and its Daughters in Bryopsis Plumosa

Radium and its Daughters in Bryopsis Plumosa

Natural, as well as artificial gamma emitters have been monitored systematically since 1984 in marine environmental samples from the Romanian sector of the Black Sea coast under a project run by the Romanian Marine Research Institute and the Institute of Environmental Research and Engineering. The Bryopsis plumosa green alga was identified as having the highest concentrations of radionuclides belonging to the natural radioactive series of uranium-radium and thorium, two orders of magnitude higher as compared with the other species common in the area under study. Evaluation of measurement derived and computed values of certain radionuclide concentration ratios leads to the conclusion that the alga assimilates only radium from its environment.

Ionic Currents During Regeneration of Thallus and Rhizoid From Cell Segments Isolated From the Marine Alga Bryopsis.

Cell segments isolated from the unicellular marine alga, Bryopsis plumosa, regenerated or protruded thallus (T) at one cut end and rhizoid (R) at the other cut end. Using a vibrating probe, we measured endogenous ionic currents associated with these events. Prior to the protrusion of T and R, the currents changed in various ways. When the T and R protruded at the cut ends of the segments, we detected an inwardly directed current at the regions of T and R, and an outwardly directed current in other parts of the cell segment. Both currents were strongly affected by decreases in external concentrations of Cl-, suggesting that a large part of the currents was carried by C1-. In addition, these currents decreased with a decrease in external concentrations of Mg2+, and were also reversibly eliminated by two metabolic inhibitors. This evidence suggests that the C1- -migration system involves an energy-dependent and Mg2+ -dependent process. In parallel with the generation of these currents, turgor pressure reached a maximum prior to the protrusion of T and R. The relationship between the generation of the currents, the generation of the maximum turgor pressure, and the protrusion of T and R is discussed.

Variations in Morphology and DNA Distribution Among Chloroplasts in Mature Germling Cell of Bryopsis plumosa (Hudson) C. Ag. (Chlorophyceae)

Fluorescence microscopy with the DNA-specific fluorochrome 4',6-diamidino-2-phenylindole (DAPI) revealed the presence of many intensely fluorescing areas around the giant primary nucleus in the mature germling cell of the green alga Bryopsis plumosa. Each of the fluorescent areas was irregular in shape and larger and brighter than the nucleoids scattered uniformly within the chloroplasts which could ordinarily be seen in the germling cell. Near the primary nucleus there were 40 or more small lenticular chloroplasts. They were morphologically different from the usual fusiform chloroplasts and were generally poor in starch and often lacked pyrenoids. The intensely fluorescing areas were always associated with these small perinuclear chloroplasts, implying that they were nucleoids of these chloroplasts. Our results indicate that, among the chloroplasts in the germling cell of B. plumosa, those located near the giant primary nucleus differ from others in morphology and also in DNA distribution.

Disappearance of Chloroplast Nucleoids during Male Gamete Formation in Bryopsis plumosa (Hudson) C. Ag. (Chlorophyceae)

Changes in chloroplast nucleoids accompanying chloroplast degeneration during male gamete formation in the coenocytic green alga, Bryopsis plumosa, was observed by fluorescence microscopy using the DNA-specific fluorochrome 4',6-diamidino-2-phenylindole (DAPI). The fusiform chloroplasts of vegetative cells always included numerous nucleoids, which seemed to be scattered at random throughout the chloroplast except in the pyrenoid. When gamete formation was initiated, all chloroplasts in the male gametangia turned yellowish green. At this stage, each chloroplast assumed a moniliform shape after constriction at several sites and contained many nucleoids. Subsequently, the chloroplast divided into smaller segments, each of which was then apportioned to a young male gamete. The internal structure of the chloroplast degenerated considerably with time. Nucleoids could not be discerned with DAPI staining in chloroplasts of either young or mature male gametes, but occasionally fluorescent areas could be seen within the cytoplasm of the gametes. In contrast, many nucleoids were always observed in the female gamete chloroplast. This study indicates that chloroplast nucleoids disappear during an early stage of male gamete formation. However, chloroplast DNA may be retained at a level beyond the resolution of the detection method.

Cell wall constituents of several siphoneous green algae in relation to morphology and taxonomy

Cell wall hydrolysates of the gametophytic phases of Bryopsis plumosa and Derbesia tenuissima contained large amounts (= percentages of more than 10) of xylose and glucose, whereas walls of the sporophytic phases contained large amounts of mannose and glucose. Xylan was demonstrated by infrared spectrometry in the cell walls of the gametophytic phases of these two species and mannan in the sporophytic phases. However the cell walls of both the gametophytic and sporophytic phases of the taxonomically related species Bryopsidella neglecta contained large amounts of xylose and glucose, and the presence of xylan in the cell wall of the sporophyte could be confirmed by infrared spectrometry. Mannan was also demonstrated in the cell walls of Codium and Pseudobryopsis. The hydrolysates of these walls contained large amounts of mannose. The hydrolysates of utricleless or juvenile stages of Codium also contained large amounts of glucose. Dominant monosaccharides in the cell walls of Caulerpa proved to be glucose, ...

Food preference and food consumption in relation to growth ofLimapontia capitata(Opisthobranchia, Sacoglossa)

Abstract The food spectrum of Limapontia capitata (Opisthobranchia, Sacoglossa) is tentatively determined. A food preference among the algal species eaten by Limapontia capitata i.e. Cladophora spp., Chaetomorpha linum, and Bryopsis plumosa could not be detected. It is suggested that the restricted food spectra of sacoglossans are due to the chemical structure of algal polysaccharides as well as to the diameter and cell size of the algal species. A positive correlation between food consumption and growth at various temperatures is established. The calorific value of mean food intake is estimated to be 0.3 0.4 cal /8 days per adult animal at room temperature.

Ultrastructure and Phototaxis of the Zoospores of Phlyctochytrium sp., an Estuarine Chytrid

Summary: Zoospores of an estuarine fungus isolated from Bryopsis plumosa and tentatively identified as a species of Phlyctochytrium were positively phototactic. Electron microscopy revealed a complex of organelles consisting of a relatively electron opaque, membrane-bounded sac, a lipid droplet and a highly ordered array of membranous tubular units which may have been involved in photoreception. The ribosomes of the zoospores were aggregated into a nuclear cap and separated from the rest of the cytoplasm by mitochondria, the nucleus, membranous sheets and membrane-bounded vesicles. There was a vestigial kinetosome nearly parallel to the functional kinetosome. A Golgi-like body was associated with the nucleus.