bluuebunny/crossref_metadata_2025_split huggingface dataset:
PHYSIOLOGICAL AND PHOTOSYNTHETIC CHANGES DURING THE FORMATION OF RED APLANOSPORES IN THE CHILOROPHYTE HAEMATOCOCCUS PLUVIALIS1
Authors: Zlotnik (Shmerler) Ita , Sukenik Assaf , Dubinsky Zvy 
Published: August 2006

ABSTRACTChanges in physiological and photosynthetic parameters were followed in the freshwater chorophyte Haematococcus pluvialis Flotow (Volvocales) during the transformation of green vegetative cells to red aplanospores.Formation of aplanospores was induced by exposure to a nitrogen‐deficient medium. In spite of an increase in cellular volume (from 6.6 to 41 pL) and amassive accumulation of astaxanthin, chlorophyll content of the mature aplanospore decreased only slightly (from 16 to 14.8 pg'cell−1)as compared to the vegetative cell. Aplanospore formation was characterized by a gradual reduction in the maximal photosynthetic rate and increases in the photosynthetic quantum requirement and minimal turnover time for photosynthetic O2 evolution.Respiration rate increased (4.2 times)and excretion rate decreased (up to 8.8 times) during aplanospore formation. Measurements of photosynthetic unit “size” and estimation of the cellular content of photosystem II reaction centers suggest that the photosynthetic complex remains relatively centers stable during the formation process and in the mature aplanospore.A functional relationship between the describe changes in the physiology of the cells and their photosynthetic parameters is proposed.
LIGHT AND ELECTRON MICROSCOPICAL OBSERVATIONS OF THE DINOFLAGELLATE ACTIMSCUS PESTASTERIAS (DINOPHYCEAE)1
Authors: Hansen Gert 
Published: August 2006

ABSTRACTI examined the heterotrophic non‐armored dinoflaget‐late Actiniscus pentasterias (Ehrenberg) Ehrenberg by light and electron microscopy. Actiniscus pentasterias contains an internal skeleton consisting of two star‐like siliceous elements. Special emphasis is given to the flagellar apparatus, the nucleus, and a new type of extrusome, named a docidosome. A three dimensional model of the flagerllar apparatus includes a fibrous nuclear connnective, a posterior striated root, and a dorsal striated component of the longitudinal microtabular root. The nucleus is surrounded by a conspicuous fibrous lamina, also visible in the light microscope. The nuclear pores are situated in annulated invaginations of the nuclear envelope, increasing the nuclear surface area by 15–25%. The docidosomes are rod‐shaped membrane‐bound structures that terminate in a distinct proximal head. They show very complex substructure, consisting of an inner medulla with highly ordered paired ribbons and an outer cortex.
SCRIPPSIELLA VELELLAE SP. NOV. (PERIDINIALES) AND GLOEOKINIUM VISCUM SP. NOV. (PHYTODINIALES), DINOFLAGELLATE SYMBIONTS OF TWO HYDROZOANS (CNIDIARIA)1,2
Authors: Banaszak Anastazia T. , Iglestas‐Prieto Roberto , Trench Robert K. 
Published: August 2006

ABSTRACTThe alga symbiotic with the “By the Wind Sailor”Vellela vellela L. (Hydrozoa, Chondrophora) collected off the coast of California, and the alga symbiotic with the hydrocoral Millepora dichotoma Forskal (Hydrozoa, Milleporina) from the Gulf of Aqaba, were isolated and brought into unialgal, axenic culture. Based on light microscopy and ultrastructure analyses by transmission and scanning electron microscopy, the algal population from V. velella is described as Scrippsiella velellae sp. nov. (Peridiniales). The algal population from the dark morph of M. dichotoma is decribed as Gloedinium viscum sp. nov. (Phytodiniales). These are the first descriptions of symbiotic dinoflagellate belonging to the orders Peridiniales and Phytodiniates. When viewed with descriptions of symbiotic dinoglagellates belonging to the Prorocentrales and Gymnodiniales, the evidence currently points to seven genera in four orders of dinoflagellates having representatives that have entered a symbiotic mode of existence.
MACROALGAL RECRUITMENT IN A HIGH MARSH CREEK OF NORTH INLET ESTUARY, SOUTH CAROLINA1
Authors: Flavier Albert B. , Zingmark Richard G. 
Published: August 2006

ABSTRACTThe temporal and spatial variability in recruitment patterns of macroalgae were stuided by evaluating the appearace of propagules on marble tiles set over a depth gradient in a high marsh tidal creek in North Inlet Estuary, South Carolina. Ulvoids and Porphyra occurred over a wide range of depths in the intertidal zone unlike Ectocarpus and members of the Florideophycease, which grew over a more restricted zone. Ulvoid propagules were the most abundant, attaining maximum densities at 0 and ‐15 cm mean low water (MLW) at all seasons except winter. In summer, coincident with high tubbidity, ulvoid densities decreased at ‐15 cm MLW but not in other seasons. Ulvoid densities at 0 MLW were depressed in January, February was preceded with the lowest recoreded temperatures and salinities during the study period, while the decrease in July was preceded by the highest recorded temperature. The number of taxa was highest in April and September, representing winter‐spring and summer‐fall transition periods, respecitively. The biomass of adult forms was higher on the tiles than on naturally occurring substrala, perhaps due to lack of stable suitable substrata in the field. Inhibition of subsequent recruitment by initial recreuitment was evident only on tiles submerged in October. The initial recruitment pattern of Porphyra rosengurtii coll et Cox and Ectocarpus siliculosus (Dillwyn) Lyngbye seem to determine the biomass distribution of adult forms, while that of ulvoids may be altered later by other factors. The considerable decrease in the number of adult forms compared to the initial denisties of propagules indicales high juvenile mortalities.
INFLUENCE OF NATURAL ULTRAVIOLET RADIATION ON LOTIC PERIPHYTIC DIATOM COMMUNITY GROWTH, BIOMASS ACCRUAL, AND SPECIES COMPOSITION: SHORT‐TERM VERSUS LONG‐TERM EFFECTS1, 2
Authors: Bothwell Max L. , Sherbot Darren , Roberge Andre C. , Daley Ralph J. 
Published: August 2006

ABSTRACTGrowth rates, accumulation dynamics, and species succession of periphytic diatom communities were examined in the presence and absence of natural ultraviolet (UV) radiation using a series of outdoor, continuous‐flow experimental flumes located on the South Thompson River, British Columbia. In a short‐term experiment (2–3 wk), log‐phase growth rates of naturally seeded diatom communities comprised of Tabellaria fenestrata (Lyngb.) Kütz., T. flocculosa (Roth) Kütz., Fragilaria crotonesis Kitton, and F. vaucheriae (Ehr.) Peter. exposed to 90% ambient photosynthetically active radiation (PAR) + UV were 30–40% lower than growth rates under 90% PAR alone. UV inhibition of growth rate was independent of the degree of P limitation within the range of relative specific growth rates (μ:μmax‐P) of 0.5–1.0. In a long‐term trial, inhibition of attached diatom accumulation under 90% PAR + UV during the first 2–3 wk was corroborated. Reduction of full sunlight to 50% PAR + UV prevented the initial inhibition phase. The initial inihibitory effect of 90% PAR + UV on algal accumulation was reversed after 3–4 wk, and by 5 wk total diatom abundance (chlorophyll a, cell numbers and cell biovolumes) in communities exposed to PAR + UV were 2–4‐old greater than in communities protected from UV. Under 90% PAR + UV and 50% PAR + UV, a succession to stalked diatom genera (Cymbella and Gomphoneis) occurred. Species succession under UV radiation doubled the mean cell size of the diatom communities. The shift from inhibition to a long‐term increase in the autotrophic community under PAR + UV compared to PAR alone provides further evidence against the use of short‐term incubation experiments to define the long‐term implications of increases in UVB. These results suggest that the ecological effects of present‐day levels of UVB and UVB:UVA ratios on autotrophic communities are not well understood and might be mediated through complex trophic level interactions.
COMPARATIVE EFFECTS OF pH AND ALUMINUM ON SILICA‐LIMITED GROWTH AND NUTRIENT UPTAKE IN ASTERIONELLA RALFSII VAR. AMERICANA (BACILLARIOPHYCEAE)1
Authors: Gensemer Robert W. , Smith Ralph E. H. , Duthie Hamish C. 
Published: August 2006

ABSTRACTThe acidophilic diatom Asterionella ralfsii cf. var. americana Körn. was grown in continuous culture to examine the influences of both pH and Al on Si‐limited growth and uptake kinetics. In contrast to nutrient‐replete cultures of A. ralfsii, lowering pH from approximately 6 to 5 reduced algal cell density, chlorophyll a concentration, and intensity of in vivo fluorescence (IVF) at steady state. The lower pH treatments were also characterized by lower Si cell quotas and higher residual dissolved Si concentrations in chemostats with similar nutrient supply rates. Physiological responses to Al stress differed from those to pH reduction when cultures were Si‐limited. Nominal Al additions of 20 μmol·L−1 reduced chlorophyll a concentration and IVF values at higher pH, but all other biomass and chemical parameters remained constant at steady state. The combined efects of Al and reduced pH were more severe than either stress alone, inducing culture washout at pH 4.8. Short‐term Si uptake experiments performed at pH 6 showed that Al influenced Michaelis‐Menten parameter estimates. Half‐saturation (Ks and maximum uptake rate (Vm) constants increased approximately 8‐ and 2‐fold in the presence of Al, respectively, but this difference was only significant for Vm. Similar to previously observed effects of Al on cell morphology in A. ralfsii, Si uptake kinetics were more sensitive to Al additions than to Silimited growth per se.
THE BIOCHEMICAL COMPOSITION OF MARINE MICROALGAE FROM THE CLASS EUSTIGMATOPHYCEAE1
Authors: Volkman John K. , Brown Malcolm R. , Dunstan Graeme A. , Jeffrey S. W. 
Published: August 2006

ABSTRACTThe biochemical composition of four strains of microalgae from the class Eustigmatophyceae was determined to assess their usefulness as live feeds for mariculture and to establish characteristic features for use in chemotaxonomic studies. We studied Nannochloropsis salina (strain CS‐190) from Scotland, two strains of Nannochloropsis oculata (CS‐179 and CS‐216) from Japan, and an unnamed eustigmatophyte (CS‐246) isolated from Queensland waters that appears to be closely related to N. oculata. Gross compositional features were similar: total carbohydrate ranged from 5.2% (N. oculata CS‐179) to 8.9% (N. salina) of cell dry weight. Polysaccharide comprised 74% (N. oculata CS‐179) to 88% (CS‐246) of this total. Glucose was the principal polysaccharide sugar (45.2–66.2% of total sugars). Other sugars included fucose, galactose, mannose, rhamnose, ribose, and xylose (2.0–14.0%). Arabinose was a minor constituent in all species (0.6–1.7%). Protein varied from 17.8% (N. salina) to 22.1% (N. oculata CS‐216) of the cell dry weight. The major amino acids were arginine, glutamate, and asparatate (7.2–10.4% of total amino acids), with methionine, cystine, histidine, tryptophan, hydroxy‐proline, ornithine, and γ‐aminobutyric acid much less abundant (0.03–2.6%). Lipid content ranged from 8.2% (N. oculata CS‐216) to 16.9% (N. salina) of cell dry weight, the latter value reflecting enhanced concentrations of triacylglycerols in N. salina. The major fatty acids were palmitic acid (16:0), palmitoleic acid [16:1(n‐7)], and eicosapentaenoic acid [20:5(n‐3)] with lesser amounts of lauric acid (14:0), linoleic acid [18:2(n‐6)], and others. The sterols consisted almost entirely of cholesterol, which is an essential constituent of crustacean diets. Chlorophyll a ranged from 0.6% (N. oculata CS‐216) to 1.7% (N. oculata CS‐179 and N. salina) of cell dry weight. Chlorophylls b and c were not detected. All strains contained a characteristic pattern of carotenoid pigments, which included violaxanthin, β‐carotene, zeaxanthin, and a pigment tentatively identified as vaucheriaxanthin‐ester. The distinctive pigment and lipid compositional data can be used as chemotaxonomic markers for Nannochloropsis and for assigning microalgae to the class Eustigmatophyceae. Nannochloropsis oculata is widely used as an algal feed in mariculture, and based on the similarity of the biochemical data, both N. salina and the unnamed tropical species should also prove to be nutritionally valuable live algal feedstocks. Feeding trials will be needed to confirm this.
VARIATIONS IN FLORIDOSIDE CONTENT AND FLORIDOSIDE PHOSPHATE SYNTHASE ACTIVITY IN PORPHYRA PERFORATA (RHODOPHYTA)1
Authors: Meng Jianxin , Srivastava Lalit M. 
Published: August 2006

ABSTRACTThe diurnal and seasonal variations in floridoside content and floridoside phosphate synthase (FPS) activity were measured in samples of Porphyra perforata J. Ag. growing in the field. Floridoside content generally increased about fourfold from early morning to the middle of the day and then dropped gradually in the afternoon and the evening. On a monthly basis, there was a steady increase in floridoside content from February to May. A similar trend in monthly increase in FPS activity was also observed from February to April. The level of FPS activity varied with the time of day. The highest activity was observed early in the morning shortly after dawn; subsequently, it decreased, reaching about 50% of the peak value late in the afternoon/evening. On a daily as well as seasonal basis, a change in FPS activity correlated with a change in floridoside content. Among environmental factors, floridoside content and FPS activity showed a positive correlation with daylength and temperature on a seasonal basis. However, on a daily basis, salinity and water temperature did not seem to affect the floridoside content or the FPS activity.
A SIGNAL GLYCOPROTEIN WITH α‐d‐MANNOSYL RESIDUES IS INVOLVED IN THE WOUND‐HEALING RESPONSE OF ANTITHAMNION SPARSUM (CERAMIALES, RHODOPHYTA)1
Authors: Kim Gwang Hoon , Fritz Lawrence 
Published: August 2006

ABSTRACTA variety of fluorescein isothiocyanate‐labeled lectins specific for different sugar moieties were examined as probes for the wound‐healing response in the filamentous red alga Antithamnion sparsum Tokida. Among them, only concanavalin A (ConA) and Lens culrinaris agglutinin (LCA), which have specificity to α‐D‐mannosyl residues, bound specifically to repair cells during the wound‐healing process. When ConA or LCA was added at various time intervals after wounding, it first bound (3 h post‐wounding) as a thin layer at the tips of the adjacent cells. Later (4–5 h post‐wounding) labeling also appeared at the tips of the repair cells. Intense labeling at these sites continued throughout the healing process until repair cell fusion, at which time the lectin labeling was reduced to a narrow ring around the area of fusion. When added to plants prior to wounding and continually monitored, these same lectins acted as inhibitors to the wound‐healing response. Other control lectins showed no inhibitory effects. A crude extract solution obtained from decapitated filaments stimulated the wound‐healing response, and a lectin‐binding component bound strongly to a protein‐binding transfer membrane. These results suggest that the labeled compound is a glycoprotein that has α‐D‐mannosyl residues and is similar to the repair hormone rhodomorphin found in Griffithsia pacifica Kylin.
PARTIAL CHARACTERIZATION OF THE CHLOROPLAST GENOME FROM THE CHROMOPHYTIC ALGA SYNURA PETERSENII (SYNUROPHYCEAE)1
Authors: Wee James L. , Chesnick Joby , Cattolico Rose Ann 
Published: August 2006

ABSTRACTHoechst dye 33258‐CsCl density gradients were used to isolate two satellite DNA species from Synura petersenii Korsh. sensu lato, a member of the Synurophyceae. One satellite DNA was identified as the chloroplast genome. The chloroplast genome is the smallest (91.5 kb) published for any chromophyte and approximates the size of the smallest functional chlorophyte chloroplast genome (Codium fragile, 89 kb). The second satellite DNA was small (34.5 kb), and its origin is undetermined. The potential of using the S. petersenii chloroplast genome in comparative studies for evaluating organellar evolution and algal systematics is discussed.
PROROCENTRUM BELIZEANUM, PROROCENTRUM ELEGANS, AND PROROCENTRUM CARIBBAEUM, THREE NEW BENTHIC SPECIES (DINOPHYCEAE) FROM A MANGROVE ISLAND, TWIN CAYS, BELIZE1
Authors: Faust Maria A. 
Published: August 2006

ABSTRACTThree new benthic dinoflagellate species, Prorocentrum belizeanum, Prorocentrum elegans, and Prorocentrum caribbaeum, from mangrove floating detritus are described from scanning electron micrographs. Species were identified based on shape, size, surface micromorphology, ornamentation of thecal plates, and architecture of the periflagellar area and intercalary band.Cells of P. belizeanum are round to slightly oval with a cell size of 55–60 μm long and 50–55 μm wide. Areolae are round and numerous (853–1024 per valve) and range from 0.66 to 0.83 μm in size. The periflagellar area of P. belizeanum is a broad V‐shaped depression; it accommodates a flagellar and an auxiliary pore and a flared, curved apical collar. The intercalary band of P. belizeanum is horizontally striated.Prorocentrum elegans is a small species 15–20 μm long and 10–14 μm wide, with an ovate cell shape. The thecal surface is smooth. Two sizes of valve pores were recognized: large, round pores (20–22 per valve) arranged in a distinct pattern and smaller pores situated in an array along the intercalary band. The periflagellar area is V‐shaped; it accommodates an uneven sized flagellar pore, an auxiliary pore, and an angled protuberant flagellar plate. The intercalary band is transversely striated. It is a bloom‐forming species.Prorocentrum caribbaeum cells are heart‐shaped with a rounded anterior end and a pointed posterior end. Cells range from 40 to 45 μm long and 30 to 35 μm wide. Thecal surface has two different‐sized pores: large, round pores (145–203 per valve) arranged perpendicularly from the posterior margins, and small, round pores unevenly distributed on the thecal surface. The periflagellar area is ornate. It is V‐shaped with a curved apical collar located next to the auxiliary pore; a smaller protuberant apical plate is adjacent to the flagellar pore. The intercalary band is transversely striated and sinuous. Cells are active swimmers.
ANTIVIRAL ACTIVITY OF CULTURED BLUE‐GREEN ALGAE (CYANOPHYTA)1
Authors: Patterson Gregory M. L. , Baker Kathleen K. , Baldwin Cynthia L. , Bolis Christine M. , Caplan Faith R. , Larsen Linda K. , Levine Ira A. , Moore Richard E. , Moore E. , Nelson Carrie S. , Tschappat Kathryn D. , Tuang Grace D. , Boyd Michael R. , Cardellina John H. , Collins Ralph P. , Gustafson Kirk R. , Snader Kenneth M. , Weislow Owen S. , Lewin Ralph A. 
Published: August 2006

ABSTRACTLipophilic and hydrophilic extracts from approximately 600 strains of cultured cyanophytes, representing some 300 species, were examined for antiviral activity against three pathogenic viruses. Approximately 10% of the cultures produced substances that caused significant reduction in cytopathic effect normally associated with viral infection. The screening program identified the order Chroococcales as commonly producing antiviral agents.
A COMPARATIVE STUDY OF TEMPERATURE RESPONSES OF CARIBBEAN SEAWEEDS FROM DIFFERENT BIOGEOGRAPHIC GROUPS1
Authors: Pakker Hans , Breeman Anneke M. , Prud'homme van Reine Willem F. , van den Hock Chris 
Published: August 2006

ABSTRACT Temperature tolerances were determined for Caribbean isolates (total 31) of seaureds belonging to three distributional groups: 1) species confined to the tropical western Atlantic (Botryocladia spinulifera, Chamaedoris peniculum, Cladophoropsis sundanensis, Dictyopteris justii, Dictyurus occidentalis, Haloplegma duperreyi, and Heterosiphonia gibbesii); 2) amphi‐Atlantic species with a (sub)tropical distribution that have their northern boundary in the eastern Atlantic at the tropical Cape Verde Islands (Bryothamnion triquetrum and Ceramium nitens) or the subtropical Canary Islands (Ceratodictyon intricatum, Coelothrix irregularis, Dictyopteris delicatula, Ernodesmis verticillata, and Lophocladia trichoclados; and 3) species with an am‐phi‐Atlantic tropical to warm‐temperate distribution also occurring in the Mediterranean (Cladophoropsis membranacea, Digenea simplex, Microdictyon boergesenii, and Wurdemannia miniata). For some isolates, growth response curves and temperature requirements for reproduction were also determined. Growth occurred in the range (18)20–30° C with optimum growth rates at 25°–30°C, irrespective of distribution group. Reproduction generally occurred at (20)25°–30° C although there were some exceptions. Species were extremely stenothermal, with those restricted to the western Atlantic surviving a total range of only 10/13° C (between 18/20° and 30/33° C). Tolerance to high temperatures was correlated with vertical position in the iniertidal/subtidal zone rather than biogeography grouping. Species restricted to the subtidal were the least tolerant, with permanent survival at 30° C but not at 33°C. Tolerance to low temperatures was not different in subtidal and intertidal species but was significantly better in am phi‐Atlantic than in western Atlantic species. In the former group, damage occurred at 15°–18° C but in the latter group at 18°‐20° C. We propose that these differences in low‐temperature tolerances in Caribbean populations of species from different distribution groups reflect adaptations to glacial cold‐stress in the tropical eastern Atlantic and subsequent trans‐Atlantic dispersal.
DIURNAL RECRUITMENT PATTERNS IN ALGAE: EFFECTS OF LIGHT CYCLES AND STRATIFIED CONDITIONS1
Authors: Hansson Lars‐Anders 
Published: August 2006

ABSTRACT The diel pattern in algal habitat shift between sediment and water was recorded above (shallow site) and below (deep site) the thermocline in a stratified, unproductive forest lake. Migrating algae were caught in funnel traps, and the net transport was calculated. Diel recruitment patterns varied temporally within site and spatially between sites. For most species, recruitment and sinking was low at the deep site during stratification. When stratification began to break down in August, the migratory activity increased at the deep site, suggesting that the stratified conditions affected algal migratory behavior. Although light obviously affected algal migration, recruitment often deviated from consistent diel patterns, indicating that simple light‐dark cycles are not sufficient to explain algal migratory patterns. Instead, the study suggests that some algal species have receptors able to detect several environmental variables, including light and variables associated with stratified conditions. Hence, some algal species, but not others, may be able to optimize resource needs by properly adjusting the timing for recruitment from the sediment surface in relation to the risk of being trapped below the euphotic zone by a thermocline not possible to penetrate.
DEGRADATION OF ADENINE BY PROTOTHECA ZOPFII (CHLOROPHYTA)1
Authors: Sarcina Mary , Casselton Peter J. 
Published: August 2006

ABSTRACT The purines 6‐amino‐2‐hydroxypurine and 6‐amino‐8‐hydroxypurine, not normally associated with purine degradation in algae, were isolated by high‐pressure liquid chromatography from cell extracts of Prototheca zopfii Krüger grown with adenine as the sole nitrogen source.