bluuebunny/crossref_metadata_2025 huggingface dataset:
PHOSPHATE AND SILICATE GROWTH AND UPTAKE KINETICS OF THE DIATOMS ASTERIONELLA FORMOSA AND CYCLOTELLA MENEGHINIANA IN BATCH AND SEMICONTINUOUS CULTURE1
Authors: Tilman David , Kilham Susan Soltau
Published: August 2007

Information on the nutrient kinetics of Asterionella formosa Hass. and Cyclotella meneghiniana Kutz. under either phosphate or silicate limitation was obtained for use in a Monod model and in a variable internal stores model of growth. Short‐term batch culture growth experiments were fit to the Monod model and long‐term semicontinuous culture experiments and short‐term uptake experiments were fit to the variable internal stores model. Mathematical analysis indicates that the parameters of the 2 models may be expressed in terms of each other at steady state.

The qualitative results of both batch and steady state culture methods agree. For limiting phosphate experiments. A. formosa is better able to grow at low PO4‐P concentrations than C. meneghiniana, as shown by its lower K for PO4‐P limited growth. The kQ of A. formosa compared to C. meneghiniana found in long‐term semicontinuous culture indicates that A. formosa is almost an order of magnitude more efficient at using internal phosphate for growth. The qualitative results under silicate‐limited growth of C. meneghiniana is less than that of A. formosa. The kQ from semicontinuous culture experiments indicates that C. meneghiniana is the more efficient at using internal silicate for growth. Nutrient uptake experiments showed more variability from a Michaelis‐Menten relationship than short‐term growth experiments. There were no significant differences between the 2 species in half saturation constants for either phosphate or silicate uptake. We observed a marked dependence of the coefficient of luxury consumption (R) of phosphate on the steady state growth rate. A. formosa has a higher R than C. meneghiniana.
REGULATION OF GAMETOGENESIS IN SCENEDESMUS OBLIQUUS (CHLOROPHYCEAE)1
Authors: Cain Jerome R. , Trainor Francis B.
Published: August 2007

The effects of nutrients, temperature and light on gametogenesis in Scenedesmus obliquus (Turp.) Kütz, were studied in culture. Concentrations of nitrogen in the medium employed showed a marked influence on gamete production. Gametogenesis is inhibited by N excess but is not a response to N starvation or depletion. A drop in N level from that of the growth medium is not required, nor does it per se trigger gametogenesis. The N concentration satisfying growth requirements insufficiently low to permit sexual differentiation. Nitrogen level in the growth medium has no effect on subsequent N to maintain a typical culture. Number of gametes present at maximum production time is inversely related to N concentration, but neither time of onset of gametogenesis, nor time of maximum gamete production is affected by N concentration. Cultures incubated at 15 C in medium lacking N take a minimum of 20—24 h to develop cells irreversibly committed to gamete formation. At the concentrations tested, no medium component other than the N‐containing salt affected gametogenesis. Temperature influences both time of maximum production and numbers present at maximum production time. Time of maximum production is inversely related to incubation temperature; a 15 C incubation temperature yielded highest gamete production. Light enhances gametogenesis but gamete formation can occur in absence of light. Achievement of a light‐saturated response is dependent upon illumination given at two critical periods: one occurs shortly after N withdrawal; the other occurs later, when cells are becoming irreversibly committed to gamete formation. Ability to produce gametes diminished with prolonged laboratory culture.
THE PATH OF CARBON IN PHOTOSYNTHESIS BY MARINE PHYTOPLANKTON12
Authors: Beardall J. , Mukerji D. , Glover H. E. , Morris I.
Published: August 2007

Using cultures of a number of different marine algae (diatoms Skeletonema costatum (Grev.) Cleve and Phaeodactylum tricornutum Bohlin, chrysophyte Isochrysis galbana Parke, green flagellate Dunaliella tertiolecta Butcher, dinoflagellate Gonyaulax tamarensis Lebour) the short‐term, pattern of 14CO2 assimilation has been investigated. In all except D. tertiolecta the labelling of amino acids and intermediates of the tricarboxylic acid (Krebs) cycle was significantly heavier than that of sugar phosphates. Over periods of 30–120 s labelling in amino acids and Krebs cycle intermediates accounted for 41–95% of the 14C fixed (depending on the alga). Over shorter times (< 10 s) the pattern in the 2 diatoms showed significant labelling of C4 acids (and related com‐pounds) and little labelling of sugar phosphates. The reverse wits seen with D. tertiolecta. Also, in the 2 diatoms and in G. tamarensis significant inhibition of photosynthesis by oxygen could only be achieved with 100% oxygen; atmospheric levels having little effect. Parallel measurements of 2 carboxylating enzymes showed that ribulose‐1,5‐diphosphate carboxylase (RuDPCase) was significantly greater than phospho (enol)pyruvate carboxylase (PEPCase) activity only in the green flagellate. It is suggested that photosynthesis in marine diatoms depends on an active PEPCase utilizing bicarbonate as a substrate and that a less active RuDPCase utilizes CO2. In D. tertiolecta the pattern more closely resembles that of a “Calvin (C3)” plant. The dinoflagellate and the chrysophyte appeared to show a mixed C3 and C4 photosynthesis.
SPECIFIC ASSOCIATIONS OF THE BLUEGREEN ALGAE ANABAENA AND APHANIZOMENON WITH BACTERIA IN FRESHWATER BLOOMS1
Authors: Paerl Hans W.
Published: August 2007

Scanning electron micrographs and autoradiographs of Anabaena circinalis Rabenh. and Aphanizomenon flos‐aquae (L.) Ralfs in samples from fresh‐water communities show that bacteria are attached specifically at the polar region of heterocysts of these known N2 fixers. This algal‐bacterial association occurs most frequently during bloom conditions. The possible roles of this association in maintaining nuisance bloom conditions are discussed.
THE RATE OF TRANSLOCATION IN ALARIA ESCULENTA (LAMINARIALES, PHAEOPHYCEAE)12
Authors: Buggeln Richard G.
Published: August 2007

The rate of translocation of organic carbon in blades of Alaria esculenta (L.) Grev. (Laminariales) was calculated from blade growth data. The cross sectional area of sieve filaments in the midrib medulla was estimated from light microscopic examination of fresh material. Files of these filaments form a perimedullar ring occupying ca. 2/3 of the medulla. Values computed for specific mass transfer of carbon into the blade meristem ranged from 36.2 to 60.8 mg C.wk−1.0.1 mm−2 sieve filaments.
ISOLATION AND PHYSIOLOGICAL STUDIES ON THREE ISOLATES OF AMPHORA (BACILLARIOPHYCEAE)1
Authors: Cooksey K. E. , Chansang H.
Published: August 2007

Three clones of the diatom Amphora were euryhaline, able to grow autotrophically at 160 lx (0.001 ly/min) and heterotrophically on glucose and fructose. Furthermore 2 clones grew on glutamate and feast extract. Light‐limited growth of individual clones was stimulated by glycerol, galactose, lactate, acetate, aspartate and asparagine, although mannose torn inhibitory at low and high light levels. The half‐saturation constant for growth of A. coffeaefomis var. perpusilla Grunow (Cleve) with glucose was 25 μM. Heterotrophic growth rate of this organism became saturated with respect to glucose at 0.5 mM.
THE KINETICS OF ORGANIC ACID UPTAKE BY THREE CHLOROPHYTA IN AXENIC CULTURE1
Authors: Bollman R. C. , Robinson G. G. C.
Published: August 2007

The uptake of 814C‐labelled dissolved carboxylic acids byAnkistrodesmus falcatus(Corda) Ralfs,Chlamydomonas segnisEttl andChlorellasp. was measured. The acids were acetic, citric, fumaric, glycollic, lactic, malic, pyruvic and succinic acids. For some substrates uptake was active, but for others it was apparently passive. The respiratory loss of substrates ranged from 5.0 to 95.0% of the total amount of C assimilated. The potential ability of these organisms to compete with bacterial populations for such substrates in natural waters was examined. In terms of the kinetics of assimilation it appeared thatA. falcatusmight compete successfully for glycollate, lactate, pyruvate and succinate; C. segnisfor glycollate and lactate andChlorellasp. for lactate, malate and possibly glycollate. Calculated replacement times of the algae on the 8 substrates did, however, indicate that although they might compete successfully for some substrates they were generally unable to grow upon them at the concentrations provided.
ULTRASTRUCTURE, DEVELOPMENT AND CYTOPLASMIC ROTATION OF SETA‐BEARING CELLS OFCOLEOCHAETE SCUTATA(CHLOROPHYCEAE)1
Authors: Marchant Harvey J.
Published: August 2007

Part of the cytoplasm, which always contains the plastid, of seta‐bearing cells ofColeochaete scutataBréb. rotates clockwise about the base of the seta. Many golgi bodies, vesicles and much endoplasmic reticulum occupy the bridges between the rotating central core of cytoplasm and the stationary peripheral layer of these cells. The setae, which grow from their base, are devoid of organelles other than vesicles and elongate mitochondria. At irregular intervals along the thin seta wall are annular thickenings containing callose. Microtubules which encircle the base of the seta disappear on treatment with colchicine. This drug had no effect on the speed of rotational streaming or the growth rate of existing hairs but did inhibit the development of new setae. Cytochalasin B slowed, but did not stop, streaming after 3 h exposure. However caffeine, but not EDTA, EGTA or the Ca ionophore A23187, reversibly inhibited cyclosis. The mechanism of cytoplasmic rotation is discussed in the light of these drug treatments and the presence of actin in the alga.
ANTIVIRAL SUBSTANCES FROM CALIFORNIA MARINE ALGAE1
Authors: Ehresmann D. W. , Deig E. F. , Hatch M. T. , DiSalvo L. H. , Vedros N. A.
Published: August 2007

Extracts of 28 species of marine macroscopic algae collected from various coastal habitats of northern California were examined for antiviral activity against a broad spectrum of mammalian viruses. Ten members of Rhodophyta contained substance(s) which caused greater than a 2 log reduction in the infectivity of herpes simplex virus types 1 and 2. In addition, anti‐Coxsackie Bs virus activity was detected in extracts of Constantinea simplex Setchell. The physical and chemical properties of the substance in extracts of Farlowia mollis (Harvey and Bailey) Farlow and Setchell and C. simplex indicated the active agent was a structural polysaccharide.
ACCUMULATION OF WATER SOLUBLE PHOSPHORUS AND HYDROLYSIS OF POLYPHOSPHATES BY CLADOPHORA GLOMERATA (CHLOROPHYCEAE)1,2
Authors: Lin C. Kwei
Published: August 2007

Concentrations of hot‐water extractable phosphorus from most samples of Cladophora glomerata (L.) Kütz. were relatively high (0.06–0.68%) and correlated closely with total dissolved P in ambient Lake Michigan water. Cladophora was able to hydrolyze polyphosphates by enzymes found in intracellular, extracellular and cell wall fractions. The intracellular phosphatase activity is pH dependent with the optimal hydrolysis rate at pH 7.8. Secretion of phosphatases is affected by pH, with maximum rate at 7, but affected little by light intensity. Magnesium is the most effective metallic cofactor required for maximal rates of intracellular phosphatase activities.
THE GLUCOSE TRANSPORT SYSTEM OFAMPHORA COFFEAEFORMIS(BACILLARIOPHYCEAE)1
Authors: Chansang H. , Cooksey K. E.
Published: August 2007

Amphora coffeaeformis(Ag.) Kütz. var.perpusilla(Grun.) Cleve took up glucose by an inducible transport system. The system was induced byd‐fructose,d‐mannose, as well as glucose. Somed‐pentoses also induced a glucose uptake system but it may not be the same one as that induced by hexose.d‐fructose,d‐mannose and 2‐deoxy‐d‐glucose inhibited 2 mM glucose uptake at equimolar concentration, butd‐pentoses did not. The uptake system decayed inca.5 h in the absence of glucose. The half‐saturation constant for uptake,K8wasca.0.1 mM glucose with a maximum uptake rate,Vmax=0.4 nmol/106cells‐min−1.
MERCURY INHIBITION ON PRIMARY PRODUCTIVITY USING LARGE VOLUME PLASTIC CHAMBERS IN SITU1
Authors: Blinn Dean W. , Tompkins Terrill , Zaleski Larry
Published: August 2007

Approximately 6000 l of lake water was suspended in large, clear plastic chambers in Lake Powell, Arizona. The chambers were monitored during 24 h incubation periods in the spring and summer 1974 and 1975. Physico‐chemical differences between the natural lake system and within the experimental chambers were negligible. Experimental mercury concentrations ranging from < 0.02 to 1.25 ppm were added to the chambers to determine the effect of elevated Hg concentrations on in situ primary production. Mercury concentrations were monitored in the water column of each chamber during each 24 h incubation period to determine absolute concentrations following reduction through adsorption, absorption and vaporization. At least a 40% reduction in photosynthetic activity occurred at Hg concentrations as low as 0.06 ppm. A toxic Hg threshold concentration of 0.06 ppm was demonstrated for the summer phytoplankton assemblage, but a distinct threshold concentration was absent for the spring diatom assemblage. Differences in spring and summer phytoplankton populations may suggest subtle differences in Hg sensitivity between phytoplankton assemblages in combination with temperature acting on total community metabolism.
CHLOROPLAST STRUCTURE IN THE CHLOROMONADOPHYCEAN ALGAVACUOLARIA VIRESCENS1
Authors: Heywood Peter
Published: August 2007

The chloroplasts ofVacuolaria virescensCienkowsky are present in large numbers between the cell membrane and the layer of cytoplasm surrounding the nucleus; they are disc‐shaped structuresca.3–4 μM long by 2–3 μM wide. Chloroplast bands consist of 3 opposed thylakoids with adjacent bands frequently interconnected. External to the girdle band is a chloroplast envelope separated from the cytoplasm by endoplasmic reticulum; there is no immediately apparent continuity between this endoplasmic reticulum and the nuclear envelope. Small electron‐dense spheres in the chloroplast stroma are thought to be lipid food reserve. Eyespots and pyrenoids are absent.
POST‐PLEISTOCENE DIATOM SUCCESSION IN DOUGLAS LAKE, MICHIGAN1,2
Authors: Stoermer E. F.
Published: August 2007

Analysis of fossil diatom assemblages recovered from a 12.2 m core reveals a series of distinct floristic associations. The associations present are correlated with sediment type and reflect successive stages in the development of the lake. A basal red clay sediment contains a planktonic association characteristic of large, proglacial lakes. At 10.0 m core depth, sediment type changes to fine sand containing a higher abundance of benthic species indicating reduction of water depth at the deposition site. Marl sediments begin at 9.7 m and contain an association characteristic of a small, shallow, oligotrophic lake. At 8.8 m the marl sequence is interrupted by highly organic sediment containing a eutrophic plankton association. From 8.5 to 7.6 m the sediment type grades from marl to organic, apparently reduced sediments and diatom associations present contain successively higher percentages of planktonic species associated with eutrophic habitats. By the 7.6 m level a eutrophic plankton association, similar to the modern flora, is established and remains remarkably constant to the surface of the section.
STUDIES ON THE AUTECOLOGY OF THE MARINE DIATOM THALASSIOSIRA NORDENSKIOELDII. II. THE INFLUENCE OF CELL SIZE ON GROWTH RATE, AND CARBON, NITROGEN, CHLOROPHYLL a AND SILICA CONTENT1
Authors: Durbin Edward G.
Published: August 2007

The effect of cell size on growth rates and some cellular contents of Thalassiosira nordenskioeldii Cleve has been measured at 0 and 10 C. At 0 C the growth rate did not vary with cell size. The 2 smallest clones at this temperature had reduced growth rates because of the induction of sexuality in that size range. The clones grown at 10 C showed a significant negative relationship between growth rate and valve diameter with the cell surface area/volume ratio positively related to growth rate. At both temperatures the smaller cells had proportionately more carbon and nitrogen/unit cell volume. The amount of chlorophyll a and silica/unit cell surface area increased with increasing cell surface area at both 0 and 10 C. Both the C/N and C/chl a ratios showed no significant change with cell size at either temperature but there was a significant increase in the C/chl a ratio at 0 C. The C/Si ratio decreased with increasing cell size at both 0 and 10 C.
PHYSIOLOGICAL INVESTIGATIONS ONALARIA ESCULENTA(LAMINARIALES, PHAEOPHYCEAE). II. ROLE OF TRANSLOCATION IN BLADE GROWTH1,2
Authors: Buggeln Richard G.
Published: August 2007

Laboratory studies on blade growth inAlaria esculenta(L.) Grev. showed 3 periods of rapid blade elongation during the year: October–November, February–April and late June. The first two periods are characteristic of many Laminariales; the unique June peak may reflect local nutrient conditions. While the distal blade functions as a source, supplying organic matter to the blade meristem, the stipe can be a source during periods of rapid growth or a sink during late summer when blade growth is slow. Maximum enhancement of elongation rate of blade meristems was observed in 40–50 cm blades; longer blades showed no further increase in growth rate. This blade length‐growth promotion relationship may be independent of seasonal variations in meristematic activity.14C tracer experiments suggested that separate growth promotion effects by distal blade, sporophylls and stipe were not additive in the intact thallus. The preferential source of assimilate for blade meristem growth was the distal blade. Secondary sources: sporophylls, which were activated following excision of the primary source; and stipe, which began to translocate assimilate when both sources were removed. The role of secondary sources in nature is discussed. Profiles of radioactivity in alcohol‐soluble organic matter in blades are evaluated in relation to tracer profiles in higher plants and mechanisms of translocation.
MATURATION OF ALGAL ZYGOTES: ALTERNATIVE EXPERIMENTAL APPROACHES FOR CHLAMYDOMONAS REINHARDTII (CHLOROPHYCEAE)1
Authors: Van Winkle‐Swift Karen P.
Published: August 2007

Young zygotes from crosses of Chlamydomonas reinhardtii Dang. mutant and wild‐type strains were incubated, in the presence or absence of light and/or nitrogen to determine whether continuation of conditions inducing gamete formation permits zygospore formation without loss of viability. Different culture media, continuous illumination vs. dark incubation and various durations of the maturation period were tested, for effect on zygospore germination efficiency, zygospore “burst size” and zoospore viability. Following either the routine maturation procedure of dark incubation on standard minimal medium, or following a new procedure of incubation under continuous illumination on N‐free medium, zygospore formation can be ensured and high germination efficiencies obtained within 3 days after mating. Tetrad analysis indicates meiosis occurs normally whether zygotes have been matured in the presence or absence of light or nitrogen. Preliminary data suggest an effect of increased maturation time on the transmission of cytoplasmic genes, if a N‐free continuous illumination maturation protocol is followed. Two experimental approaches for the maturation of C. reinhardtii zygotes are suggested and advantages of each are discussed.
STARRIA ZIMBABWEËNSIS (CYANOPHYCEAE) GEN. NOV. ET SP. NOV.: A FILAMENT TRIRADIATE IN TRANVERSE SECTION1
Authors: Lang Norma J.
Published: August 2007

A new filamentous bluegreen alga Starria zimbabweënsis gen. nov. et sp. nov. isolated from a soil sample collected near Zimbabwe, Southern Rhodesia, has a unique triradiate morphology. In transverse section each narrow cell possesses three arm‐like projections, separated by 120° and in which pigment is concentrated. Filaments may be straight or twisted and various clonable biradiate forms have originated in cultures initiated from the triradiate type. Cell ultra‐structure is typical of the Oscillatoriaceae except that 70 nm pit‐like pores occur throughout the L‐II layer of the longitudinal walls. Wall structure of deviant forms is identical to that of the triradiate “wild type.” The organism is assigned to the Oscillatoriaceae rather than to the Gomontiellaceae or to a new family.
ULTRASTRUCTURE OF CYST FORMATION IN OCHROMONAS TUBERCULATA (CHRYSOPHYCEAE)1
Authors: Hibberd David J.
Published: August 2007

The cysts (statospores) of Ochromonas tuberculata Hibberd are produced within a cytoplasmic silica deposition vesicle (SDV) whose membrane (silicalemma) appears to be formed by the coalescence of golgi vesicles. Silica is first deposited as small nodules and the collar and spines develop by centrifugal growth only after a complete but still thin wall has been laid down. Small vesicles appear to be attached to the SDV only in the region overlying the developing collar; a cap of radially arranged, moderately electron‐dense material occurs at the tip of the growing spines. The cyst pore is formed at the anterior end of the flagellate cell, by lack of silica deposition over a small region of the SDV and rupture of the SDV and other membranes crossing this region. When the cyst wall is complete, an extracystic plug is formed in the pore, resulting in the loss of some extracystic cytoplasm and the plasmalemma, and the inner SDV membrane becomes the functional plasmalemma. The plug develops first by coalescence with the cell membrane of golgi‐derived vesicles containing dense but apparently nonsiliceous spicules surrounded by amorphous material. During later stages of plug formation only fibrous material is deposited, some of which may be extruded through the pore forcing out some of the spiculate component. Scanning electron micrographs of the mature wall show it is smooth except for the concentrically wrinkled inner face of the flared collar and that the real pore diameter is only ca. half that of the collar. At germination the plug completely disappears in an unknown way and a single cell, similar to a normal vegetative cell emerges through the pore. Chrysophycean cyst formation generally resembles cell wall formation in diatoms, but differs in some details.
DEVELOPMENT OF MUCILAGINOUS SURFACES IN EUGLENOIDS. II. FLAGELLATED, CREEPING AND PALMELLOID CELLS OFEUGLENA1
Authors: Rosowski James R.
Published: August 2007

Critical‐point dried (CPD) cells from clonal cultures ofEuglena gracilisKlebs (Z strain),E. desesEhrb.,E. tripteris(Duj.) Klebs andE. myxocylindraceaBold & MacEntee were examined by scanning electron microscopy. Flagellated motile cells ofE. gracilisare naked except for a few strands of mucilage on the posterior tip. Flagellated cells ofE. tripterishave a permanent mucilage coating often of uneven distribution and usually not as well developed as that of nonflagellated creeping cells which have a distinctive mucilage. InE. desesthe coating appears rough due to the aggregation of isolated groups of strands above the cell surface. InE. tripteristhe coating appears smooth except for breaks near the articulation of the pellicular strips where the mucilage may rise above the surface to form waves. At high magnification this mucilage consists of a network of strands generally lying parallel to the cell surface; the strands become obscure in some specimens. InE. myxocylindraceaelongated, mucilage‐coated cells contract to form spheres which undergo further mucilage deposition producing the mucilage covering of palmellae. As palmellae mature, the mucilage surface becomes less porous and the individuality of most mucilage strands is lost.
COMPARISONS OF SALT‐MARSH FUCOID PRODUCTION ESTIMATED FROM THREE DIFFERENT INDICES1
Authors: Brinkhuis B. H.
Published: August 2007

Production of Ascophyllum nodosum (L.) LeJolis ecads and Fuscus vesiculosus L. was calculated from measurements of in situ growth, seasonal variations in standing‐crops and seasonal variations in photosynthetic capacity. A computer model for predicting daily, monthly and yearly net production from photosynthesis data was constructed. This model used daily irradiation, actual biomass of algae/m2 contributing to production and photosynthesis vs. light intensity relationships as data inputs. Comparison of production estimated from in situ growth, standing‐crops and photosynthesis indicated that both marsh fucoids turn over biomass twice per year. Total net production of both fucoids, estimated from photosynthesis data, was ca. 315 g C · m−2· yr−1. On the other hand, production of both fucoids calculated from standing‐crop data was only 155 g C · m−2· yr−1.
INFLUENCE OF NITROGEN SOURCE ON MORPHOLOGY OF RIVULARIACEAE (CYANOPHYTA)1
Authors: Sinclair Christine , Whitton Brian A.
Published: August 2007

Thirty‐four heterocyst‐producing strains of Rivulariaceae (29 Calothrix, 1 Dichothrix, 2 Gloeotrichia, 2 Rivularia), which produced tapered trichomes in medium minus combined nitrogen, were grown in the presence of nitrate. One strain was unchanged in morphology under this condition. The remaining 33 strains developed trichomes lacking heterocysts. In 19 strains almost all the trichomes became untapered and in the other 14, similar untapered trichomes were produced, but also many tapered trichomes resembling Homoeothrix or Hammatoidea. Similar results were obtained when representative strains were incubated with ammonia as the source of combined N. Only five strains formed colorless hairs in the control medium (minus combined N). The presence of combined N did not diminish hair development in the two strains which had only a few short hairs, but hair frequency and length were both reduced considerably in the three strains with many long hairs in the control medium. Two strains of the non‐heterocystous genus Homoeothrix were incubated in medium without combined N. Neither strain showed any growth or heterocyst development, indicating that neither is simply a growth form of a heterocystous genus.
STORAGE AND STRUCTURAL PRODUCTS FORMED DURING PHOTOSYNTHESIS IN THE SIPHONOUS ALGA CAULERPA SIMPLICIUSCULA(CHLOROPHYCEAE)1
Authors: Howard Russell John , Grant Bruce Raymond , Fock Heinrich
Published: August 2007

The distribution of radioactivity into storage and intermediary metabolites during photosynthesis over periods of up to three hours was followed in the siphonous green alga Caulerpa simpliciuscula C. Ag. After the first hour, almost all the carbon assimilated was recovered as insoluble 1,4‐α‐glucan. There was rapid movement of carbon into insoluble 1,3‐β‐glucans during the first 20 min of photosynthesis, but little additional carbon moved into these compounds after that time. This contrasted with the movement of carbon into the soluble 1,3‐β‐glucan fraction, which continued for 2 h. Sucrose accumulated very little 14C during the entire period of photosynthesis. There was a very slow transfer of 14C into lipid throughout the period but the rate was linear. Protein labelling showed a lag of 2 h before it reached the same rate of 14C accumulation as shown by the lipid initially. It is suggested that the distribution of radioactivity can be explained in part by proposing that the tissue is in the latter stages of recovery from the wounding which look place at the time of dividing the thallus into sections.
ALCIAN BLUE: A QUANTITATIVE AQUEOUS ASSAY FOR ALGAL ACID AND SULFATED POLYSACCHARIDES1
Authors: Ramus J.
Published: August 2007

Alcian Blue, a cationic copper phthalocyanine dye, complexes with the anionic carboxyl and half‐ester sulfate groups of acidic algal polysaccharide in aqueous solution to form an insoluble precipitate. The quantity of dye removed from solution is proportional to the quantity of polyanion in solution, and this principle forms the basis for the quantitative determination of acid and/or sulfated algal polysaccharides. The assay is linear between 0 and 100 μg/ml agar, alginic acid, carrageenan, pectin and Porphyridium aerugineum Geit. polysaccharide. In addition, the technique is used to determine the anion density of acid polysaccharides on a molar or weight equivalency basis.
PIGMENTS OF THE DINOFLAGELLATE PERIDINIUM BALTICUM AND ITS PHOTOSYNTHETIC ENDOSYMBIONT1
Authors: Withers Nancy W. , Cox Elenor R. , Tomas Ronald , Haxo Francis T.
Published: August 2007

An examination of the pigments of the binucleate dinoflagellate Peridinium balticum (Levander) Lemmerman revealed the presence of chlorophylls a, c1 and c2 and the carotenoids: fucoxanthin (most abundant), diadinoxanthin, diatoxanthin, an unidentified fucoxanthin‐like xanthophyll, β‐carotene, γ‐carotene and astaxanthin. A comparison of the pigments of P. balticum and P. foliaceum (Stein) Biecheler, also a binucleate dinoflagellate, demonstrated similar compositions. However P. balticum lacked the β‐carotene precursors (e.g. phytoene) which accumulated outside the chloroplast in P. foliaceum. This study indicates that P. balticum and P. foliaceum are closely related; each species is a heterotrophic dinoflagellate with a photosynthetic endosymbiont taxonomically affiliated with the Chrysophyta (Chrysophyceae or Bacillariophyceae).
COLONY DEVELOPMENT INEUDORINA ELEGANS(CHLOROPHYTA, VOLVOCALES)1
Authors: Gottlieb Bruce , Goldstein Melvin E.
Published: August 2007

A detailed ultrastructure study was made of cell division and colony development inEudorina elegansEhrenberg. At the onset of cell division and prior to nuclear division the nucleus moved from the cell center to the cell surface. During nuclear division the nuclear membrane remained intact, except for openings occurring at the nuclear poles. The spindle microtubules appeared to arise from a MTOC‐like (microtubule organizing centers) structure, while centrioles were absent from the nuclear poles. Following telophase, daughter nuclei formed which were separated by several distinct bands of endoplasmic reticulum. Cytokinesis occurred with formation of a cleavage furrow, associated with a typical phycoplast band of microtubules. However, cytokinesis was incomplete, resulting in formation of cytoplasmic bridges between the plakeal cells. Upon completion of up to five successive cell divisions, the plakea underwent inversion, which appeared to involve the production of colonial envelope material and rearrangement of cytoplasmic bridges. A new hypothesis concerning inversion is postulated based on these observations.
A CULTURE STUDY OF SALINITY RESPONSES IN ECOTYPES OF TWO ESTUARINE RED ALGAE1
Authors: Yarish Charles , Edwards Peter , Casey And Stephen
Published: August 2007

Laboratory culture studies on the euryhalinity of Bostrychia radicans Montagne and Caloglossa leprieurii (Montagne) J. Agardh from the mouth and head of the Mullica River estuary, New Jersey, revealed both species probably have ecotypes whose growth patterns correlate with the salinity regime of their habitat in nature. Significant growth differences of tetrasporelings were determined in response to four salinities (5, 15, 25, 35%c) even after acclimation periods of the tetrasporophytes from 6 mo–2 yr in laboratory culture. However, one isolate of Bostrychia and both isolates of Caloglossa also demonstrated some capability for physiological adaptation to salinity changes although this was less significant statistically than their ecotypic response. It thus appears that certain euryhaline algae may consist of ecotypes, each of which has some capacity for physiological adaptation to salinity variations.
VOLATILE ORGANIC SULFIDES FROM FRESHWATER ALGAE1
Authors: Bechard Marc J. , Rayburn William R.
Published: August 2007

Dimethyl sulfide (DMS) was found to be the principle biogenic sulfur compound in a freshwater environment. Endemic and non‐endemic algae were cultured under axenic and nonaxenic conditions in defined media. Sulfur gas analysis of culture fluids indicated that members of the Cyanophyta were probable sources of DMS whereas representatives of the divisions Chlorophyta, Xanthophyta and Bacillariophyta apparently did not produce this compound. Comparison of gaseous contents of young and old nonaxenic cultures of filamentous algae in the divisions Chlorophyta and Xanthophyta showed DMS occurred only in aged cultures and was probably produced by bacteria utilizing substances from senescent algal cells. Data suggest that the composition of the algal community determines whether DMS is algal and/or bacterial in origin.
DIEL CHANGES IN PHASED‐DIVIDING CULTURES OF CERATIUM FURCA (DINOPHYCEAE): NUCLEOTIDE TRIPHOSPHATES, ADENYLATE ENERGY CHARGE, CELL CARBON, AND PATTERNS OF VERTICAL MIGRATION1
Authors: Weiler Caroline S. , Karl David M.
Published: August 2007

The diel pattern of cell division, cell carbon, adenine nucleotides and vertical migration was determined for laboratory cultures of the photosynthetic marine dinoflagellate, Ceratium furca (Ehr.) Clap. & Lachm., entrained on an alternating 12:12 LD schedule at 20 C. Cell division was initiated during the latter portion of the dark period with ca. 30% of the population undergoing division. Cell C increased during the light period and exhibited a linear decrease with a loss of 33% during the dark period. ATP · cell−1 increased during the light period and decreased by ca. 40–50% during the dark period. The diel patterns of cell C and ATP tended to “buffer” the magnitude of the change in C:ATP ratios around an overall mean value of 89. There was no obvious trend in the concentration of [GTP + UTP] · cell−1 over the cell cycle. The cellular adenylate energy charge was maintained at values between 0.8 to 0.9 throughout the 24 h LD cycle, despite a ca. 40% decrease in total adenylates (AT= ATP + ADP + AMP) during the dark period on 12:12 LD, and over a 68% decrease in ATP during 42 h of continuous darkness. These data lend experimental support to the theory of cellular metabolic control by the adenine nucleotides. With lateral illumination on 12:12 LD cycles, the cells began to concentrate at the surface of the experimental tubes shortly before the lights were turned on, and at the bottom of the tubes shortly before the lights were extinguished. This pattern continued for 6 days in continuous darkness, suggesting that the vertical migration pattern is independent of a phototactic response and may be under the control of an endogenous rhythm.
VITAMIN B12‐BINDER AND OTHER ALGAL INHIBITORS1
Authors: Pintner Irma J. , Altmeyer Vicki L.
Published: August 2007

Euglena gracilisKlebs,Poterioochromonas malhamensis(Pringsheim) Peterfi,Monochrysis lutheriDroop,Isochrysis galbanaParke andPhaeodactylum tricornutumBohlin are known to release into the medium a substance which binds free vitamin B12. The binder, apparently a glycoprotein, makes vitamin B12unavailable and inhibits growth of vitamin B12‐requiring microorganisms. Culture filtrates of selected marine diatoms, chrysophytes, cryptophytes, dinoflagellates and green algae contained the binder, indicating that binder release was not restricted to any algal group. However the three prokaryotic bluegreens tested do not produce B12‐binder. Production is also independent of the nutritional requirements of the donor, being produced by autotrophs and auxotrophs. The binders produced by these marine species have similar properties: they are heat labile; inhibition is not species‐specific; it is competitive, being reversed by adding B12. Production increases with density of the culture and is not restricted to stationary or scenescent cells. The marine species tested produced much less B12than the freshwaterEuglenaandPoterioochromonas;the inhibition is reversed by 20–50 ng · 1−1of B12for marine species which reach moderate densities and by 150–300 ng · 1−1B12for the densely growing species. Consequently the binder may affect the growth of B12‐requiring species only in environments like the open ocean poor in B12. By contrast, the marine algae produce other inhibitors which are often heat stable and very inhibitory. These inhibitors, being species‐specific and less labile, may be more important in affecting the succession of algal species in natural waters.
EFFECTS OF ARSENIC SPECIATION AND PHOSPHATE CONCENTRATION ON ARSENIC INHIBITION OF SKELETONEMA COSTATUM (BACILLARIOPHYCEAE)1
Authors: Sanders James G.
Published: August 2007

Arsenate is taken up readily by Skeletonema costatum (Greville) Cleve due to its chemical similarity to phosphate, and it inhibits primary productivity at concentrations as low as 67 nM when the phosphate concentration is low. A phosphate enrichment of greater than 0.3 μM alleviates this inhibition; however, the arsenate stress causes an increase in the cell's requirement for phosphorus. Arsenite is also toxic to Skeletonema at similar concentrations. Methylated species, such as dimethylarsinic acid, did not affect cell productivity at the levels examined. Thus, the reduction and methylation of arsenate to dimethylarsinic acid by the cell produces a stable, non‐toxic compound.
GROWTH AND DIFFERENTIATION OF AXIAL AND LATERAL FILAMENTS IN BATRACHOSPERMUM SIRODOTII (RHODOPHYTA)1
Authors: Aghajanian John G. , Hommersand Max H.
Published: August 2007

Development of the vegetative gametophyte of Batrachospermum sirodotii Skuja was examined with light and both transmission and scanning electron microscopy. Patterns of wall growth were followed using the Calcofluor White ST pulse‐chase method. Thallus structure was analysed in terms of the pattern of development of the apical, periaxial and pleuridial initials that generate the axial and whorled lateral filaments characteristic of Batrachospermum. Apical cells of axial filaments elongate initially by tip growth with the nucleus maintaining a distal position. Nuclear division is horizontal. One daughter nucleus migrates basipetally and a thin, convoluted annular septum and perforate‐occluded pit connection are then formed. Elongating axial cells subsequently extend by wall deposition at the base of the cell. Periaxial cells are initiated laterally and elongate primarily by tip growth while the nucleus remains within the axial cell. The nucleus then migrates to the boundary between the initial and the axial cell, divides, and one daughter nucleus moves into the initial and the other back into the axial cell. A slightly irregular annular septum and simple‐occluded pit connection are then formed. Pleuridial cell initials begin as terminal to subterminal protuberances on periaxial or pleuridial cells. They first extend by tip growth and later by bipolar band growth. The nucleus remains within the parent cell as the pleuridial initial expands and a narrow septal ring is formed between the two cells. It then migrates through the septal ring into the initial and divides transversely. One nucleus passes back into the parent cell and a thick, flat septum and perforate‐occluded pit connection are formed. It is concluded that the potentially indeterminate axial filaments and the determinate lateral pleuridia represent distinct developmental types in Batrachospermum.
ROLE OF GOLGI APPARATUS IN MUCILAGE PRODUCTION AND CYST FORMATION INEUGLENA GRACILIS(EUGLENOPHYCEAE)1
Authors: Triemer Richard E.
Published: August 2007

Dark grown cells ofEuglena gracilisKlebs (strain Z Pringsheim) encyst when placed in minus nitrogen media for 48–72 h in the dark. The number of cisternae per dictyosome decreases from 10–20 to 6–12 during encystment. Cisternae dilate and fill with mucilage within 12–18 h after induction. The material is secreted into the reservoir and deposited onto the cell surface. The encysting cells rotate as they develop resulting in the deposition of a thick mucilaginous layer over the cell surface. The secretion product has been identified as polysaccharide with the periodic acid‐silver methenamine reaction. Mucilage has not been observed in the endoplasmic reticulum adjacent to the pellicle. The product present in the dictyosornes and on the cell surface react identically to the silver reagent.
THE DINOFLAGELLATE TRANSVERSE FLAGELLUM: THREE‐DIMENSIONAL RECONSTRUCTIONS FROM SERIAL SECTIONS1
Authors: Rees Anthony J. J. , Leedale Gordon F.
Published: August 2007

Serial sections through in situ transverse flagella of the dinoflagellate Peridinium cinctum f. irregulatum (Lindem.) Lefévre are presented. Three‐dimensional reconstructions based upon tangential and radial series show a helically coiled axoneme lying external to and distinct from an accessory strand. Hitherto undescribed vesicles within the expanded flagellar sheath are suggested to provide a decoupling effect between axoneme and strand. The flagellar axis bears two types of hair but anchoring threads between cingulum and flagellum have not been found. Functional and taxonomic implications of these observations are briefly discussed.
EFFECTS OF TEMPERATURE CONDITIONING ON DEVELOPMENT AND GERMINATION OFGONYAULAX TAMARENSIS(DINOPHYCEAE) HYPNOZYGOTES1
Authors: Anderson Donald Mark
Published: August 2007

Plankton samples from a dense bloom of the toxic red tide dinoflagellateGonyaulax tamarensisLebour were incubated in the laboratory to study the formation and development of thick‐walled, overwintering cysts. Samples, contained very few cysts, and fusing cells were seen only twice. However, thousands of elongate cysts were formed from large posteriorly biflagellated cells (presumed to be planozygotes) that comprised approximately 50% of the initial motile population. Development of these new cysts (hypnozygotes) was studied under different storage conditions. Each hypnozygote lost pigmentation and formed a thick cell wall during the first several days of storage, producing a starch‐filled cell with a yellow accumulation body. Starch reserves decreased rapidly during storage at warm (22 C) temperatures and more slowly at 5 C (with no apparent effect from light, dark, or added nutrients). Excretion of mucilaginous material was also observed. Periodic germination experiments showed that 22 C temperatures led to rapid development of the hypnozygote, with germination possible 1 mo after formation, whereas 5 C storage retarded development, with the first revivals after nearly 4 mo. Excystment was initiated only after an applied stimulus—either a temperature increase or decrease depending on the previous storage temperature. Cysts formed during the late spring in temperate waters are thus capable of excystment several months later as fall temperatures decrease; those formed in the fall take longer to mature, but are viable after six months of overwintering. Alternating spring and fall blooms seeded by germinating populations of dormant cysts are thus possible, a finding consistent with recent field observations.
NITROSOGUANIDINE AND ULTRAVIOLET LIGHT MUTAGENESIS IN EUDORINA ELEGANS (CHLOROPHYCEAE)1
Authors: Toby Anne L. , Kemp C. Lindley
Published: August 2007

Reversion of an acetate requiring strain and the induction of sectored colonies are used to establish optimal conditions for nitrosoguanidine and ultraviolet light mutagenesis in Eudorina elegans Ehrenberg. Nitrosoguanidine is more effective in causing reversion of the acetate requiring strain and inducing auxotrophs. Morphogenetic mutants are more readily induced by ultraviolet light. The effectiveness of ultraviolet light as a mutagen is cell cycle dependent whereas the mutagenic action of nitrosoguanidine is not.
SUBCELLULAR LOCALIZATION OF BROMINATED SECONDARY METABOLITES IN THE RED ALGA LAURENCIA SNYDERAE1
Authors: Young David N. , Howard B. M. , Fenical W.
Published: August 2007

Energy dispersive X‐ray fluorescence spectroscopy of thin sections of Laurencia snyderae Dawson shows bromine is concentrated in a cytoplasmic vesicle, the corps en cerise, a previously described structure characteristic of this genus. The presence of the brominated natural product β‐snyderol is shown to be related to the presence of corps en cerise in cortical cells. The presence of halogenated sesquiterpenoids in the corps en cerise of various Laurencia species is inferred from these data.
ULTRASTRUCTURE STUDIES ON SOME MASTOGLOIA SPECIES OF THE GROUP INAEQUALES (BACILLARIOPHYCEAE)1
Authors: Stephens F. Carol , Gibson Robert A.
Published: August 2007

Five species of the diatom genus Mastogloia (group Inaequales) were studied using transmitted light (TLM) and scanning electron (SEM) microscopy. Specimens for study were collected from the Indian River, Florida (salinity 16–42‰c temperature 9–34°C) as epiphytes on the sea‐grass Halodule wrightii Ashers.

Both intact frustules and individual parts of frustules are described and interpreted from TLM and SEM observations of M. angulata Lewis, M. erythraea Grun., M. manokwariensis Chain., M. pusilla Grun. and M. schmidtii Heiden. Mastogloia angulata was areolate whereas the other species were punctate. Differences in internal basal valve construction are described for the five species examined. A discussion is included of the morphological characters shown by the SEM studies which led to our use of the name M. manokwariensis for a species which might otherwise be considered, as M. pusilla var. subcapitata Hust.
PHOTOMOVEMENT RESPONSES OFPORPHYRIDIUM PURPUREUM1
Authors: Hill Sylvia A. , Towill Leslie R. , Sommerfeld Milton R.
Published: August 2007

The influence of light quality on positive phototopotaxis by the gliding, unicellular red algaPorphyridium purpureumwas obtained using interference filters. Cells exposed to 3×10−7mol · m2· s−1of various wavelengths for 72 h showed maximum topotaxis at 420 and 440 nm. The lower threshold for positive, movement was approximately 5×10−8mol · m−2· s−1. Random movement occurred at nonactinic wavelengths, and no movement occurred in the dark. Cell motility appeared to be unaffected by light polarity, suggesting that the photoreceptor(s) for topotaxis and photokinesis are randomly oriented.
AXENIC TISSUE CULTURES FROM THE SPOROPHYTES OFLAMINARIA DIGITATAANDLAMINARIA HYPERBOREA(PHAEOPHYTA)
Authors: Fries Lisbeth
Published: August 2007

Starting material for the tissue cultures was the meristematic basal zone of the blade. Pieces treated 30–60 sec in hypochlorite solution were rinsed and placed on agar plates made from the artificial seawater ASP6 F2 solidified with 6 g agar l−1. After 6 weeks colorless callus‐like tissue grew out from some pieces. Treatment with activated charcoal removed some inhibiting substances from the agar medium as numbers of callus developing pieces increased on such plates. A combination of 10−5M NAA and 5 · 10−7M kinetin gave a yellow‐brown tissue. A differentiation in the tissue fromL. hyperboreawas observed as well as the formation of meiospores, which grew out into male and female plants. Thalli of sporophytes were observed but they never reached a length of more than one mm before they died or changed to an irregular pattern of growth.
COMPARATIVE CYTOLOGY AND TAXONOMY OF THE ULVAPHYCEAE. I. THE ZOOSPORE OFULOTHRIX ZONATA(CHLOROPHYTA)1
Authors: Sluiman Hans J. , Roberts Keith R. , Stewart Kenneth D. , Mattox Karl R.
Published: August 2007

This fine structural study of the quadriflagellate zoospore ofUlothrix zonata(Weber & Mohr) Kützing, with special attention to the flagellar root system, demonstrates that it is very similar to the zoospore ofUlva lactucaL. in several aspects. Common features include the presence of a cruciate root system (4‐2‐4‐2 type), a non‐striated band that connects basal bodies, a so‐called terminal cap, and system I and system II striated root components. Only slight differences exist, i.e. in the shape of the terminal cap, and in the number and position of the system II root components. It is concluded that the taxonomic affinities ofU. zonatalie with the Ulvaphyceae sensu Stewart and Mattox rather than with the Chlorophyceae. Additional support for this conclusion is the discovery of tiny, flat body scales on the zoospore ofU. zonata.A summary of the distinctive characteristics of the Chlorophyceae, Charophyceae and Ulvaphyceae reflecting the current state of knowledge is given.