bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEXUAL REPRODUCTION OFPERIDINIUM WILLEI(DINOPHYCEAE)1
Authors: Lois Pfiester A., O.P. 
Published: August 2007

SUMMARYSexual reproduction was induced in the dinoflagellatePeridinium willeiHuitfeld‐Kass when exponentially growing cells were inoculated into nitrogen deficient medium. Small, naked vegetative cells produced by division of thecate cells acted as gametes. The zygote remained motile 13–14 days, during which time it enlarged and the theca formed became warty. Fourteen to 15 days following plasmogamy the zygote was nonmotile with the protoplast contracted. A large red oil droplet appeared and the wall thickened, becoming chitinized. Hypnozygotes with 4 nuclei were observed 7–8 wk following formation. Meiosis was inferred. The hypnozygote germinated, within 8 wk producing one post‐zygotic cell retaining the red oil droplet. This cell divided within 24 h into 2 daughter cells each with a prominent red oil droplet. These daughter cells divided after 2 to 3 days into ordinary vegetative cells. Attempts to induce sexual reproduction by inoculation of cells into media deficient in a number of basic elements were unsuccessful.
EFFECTS OF LIGHT INTENSITY ON DIVISION RATE, STIMULABLE BIOLUMINESCENCE AND CELL SIZE OF THE OCEANIC DINOFLAGELLATESDISSODINIUM LUNULA, PYROCYSTIS FUSIFORMISANDP. NOCTILUCA12
Authors: Swift Elijah , Meunier Valerie 
Published: August 2007

SUMMARYPreadapted cultures were grown in a 12:12 LD cycle at a series of light intensities under cool‐white, fluorescent lamps.Pyrocystis fusiformisMurray maintained high division rates at low light intensities at the expense of cell size. In contrast,Dissodinium lunula(Schuett) Taylor had relatively lower division rates at low light intensities with little concomitant decrease in size. The response ofP. noctilucaMurray was intermediate between these two species. For all three, cell numbers did not increase above an intensity of 5–10 μEin·m−2·sec−1and division rate was saturated atca.30, 60, and 60μEin·m−2·sec−1forP. fusiformis, P. noctiluca, andD. lunula, respectively. The capacity for stimulable bioluminescence was saturated at light intensities of 0.15 μEin·m−2·day in short‐term (2‐day) experiments. In cultures ofP. fusiformisandP. noctiluca, maintained for at least one month at lower intensities than needed to saturate division rate, a decrease in the capacity for stimulable bioluminescence was accompanied by a reduction in cell size. Our results suggest that cell size and bioluminescent capacity may prove to be a potentially useful indication of the history of exposure of natural populations ofPyrocystisspp. to ambient intensities.
THECAL ULTRASTRUCTURE OF THE TOXIC MARINE DINOFLAGELLATE GONYAULAX CATENELLA1
Authors: Postek Michael T. , Cox Elenor R. 
Published: August 2007

SUMMARYThe toxic marine dinoflagellate Gonyaulax catenella Whedon & Kofoid was studied with scanning and transmission electron microscopy to describe the thecal morphology and to accurately define the taxonomic characters of the species. The closing platelet which lies in a U‐shaped apical pore was revealed to be disassociable from a partly obscured apical platelet. Two previously unreported sulcal plates were charaterized and described. The entire complement of thecal plates numbered 33.
CHARACTERIZATION OF PIGMENT MUTANTS IN A BLUEGREEN ALGA, ANACYSTIS NIDULANS1
Authors: Stevens C. L. R. , Myers Jack 
Published: August 2007

SUMMARYCharacteristics of 2 types of pigment mutants of the bluegreen alga, Anacystis nidulans, are described. “Yellow‐green” mutants (YG) which have normal chlorophyll but only half the phycocyanin of the parent are similar to the parent in number of reaction centers/cell, number of chlorophylls/reaction center, maximum turnover rate of the reaction centers, quantum yields at 620 and 686 nm and specific growth rate; they have a reduced action at 620 nm. “Blue” mutants (BL) with somewhat higher phycocyanin but only one‐third the chlorophyll of the parent are dissimilar to the parent. BL's have fewer reaction centers/cell, a smaller number of chlorophylls/reaction center, a higher maximum turnover rate of reaction centers, and a lower specific growth rate. BL's show ca. half the quantum yield of the parent at 620 nm and at 686 nm show a “red rise” rather than a “red drop.” The consequences attending low chlorphyll in the BL's are more drastic than those attending the low phycocyanin of the YG's.
INHIBITION OF CHLORELLA (CHLOROPHYCEAE) GROWTH BY FATTY ACIDS, USING THE PAPER DISC METHOD1,2
Authors: McGrattan Carol J. , Sullivan James D. , Ikawa Miyoshi 
Published: August 2007

SUMMARYUsing the paper disc‐agar plate method, a number of fatty and related acids have been tested for tested activity for inhibiting the growth of Chlorella pyrenoidosa Chick. Of the saturated acids, a peak in growth inhibiting activity wax observed in the C7–C12 range, where inhibition wax observed when solutions down to 0.02 M were applied to the discs. Most of the unsaturated acids tested showed greater inhibition than did the corresponding saturated acids. Acrylic acid showed detectable inhibition at 0.001 M concentration.
CONTINUOUS CULTURE OF MARINE DIATOMS UNDER SILICATE LIMITATION. II. EFFECT OF LIGHT INTENSITY ON GROWTH AND NUTRIENT UPTAKE OFSKELETONEMA COSTATUM1,2
Authors: Davis Curtiss O. 
Published: August 2007

SUMMARYTwo replicate experiments were conducted to investigate the effect of light intensity on the growth and nutrient uptake ofSkeletonema costatum(Grev.) Cleve in silicate‐limited continuous culture. Each experiment began with 4 identical chemostat cultures ofS. costatumgrowing at the normal laboratory light (0.14 ly · min−1, continuous illumination) under strong silicate limitation. Screens were placed over 3 cultures reducing them to light intensities of 0.042, 0.021 and 0.0018 ly · min−1.Based on growth rules, nutrient uptake rates, cell morphology and chemical composition, the cultures receiving 0.021, and 0.0018 ly · min−1appeared to he light‐limited, whereas the culture receiving 0.14 ly.
A COMPARISON OF THE ATTACHED ALGAL COMMUNITIES OF A NATURAL AND AN ARTIFICIAL SUBSTRATE1
Authors: Brown Helen Davis 
Published: August 2007

SUMMARYA study of communities of attached algae in Lake Mize Florida, wax made during July 1969, July‐August 1970 and April 1971. The substrates exposed during the study included glass slides mid the terrestrial form of the amphibious sedge, Eleocharis baldwinii (Torr.) Chapman. Counts were used to determine the relative abundance and densities of the species present on the 2 substrates under different environmental conditions. Such analyses indicated that at any given lime and place, a number of factors influenced the composition of the periphyton. Generally, lightly adhering, resupinate species attained higher densities on glass slides than filamentous and loosely associated metaphytonic species. The epiphytic flora of E. baldwinii contained a large number of both strong attachers and the metaphyton. The vertical range of many attached species was also greater on E. baldwinii than on glass slides.
EXTRACELLULAR LYSIS OF THE BLUEGREEN ALGA PHORMIDIUM LURIDUM BY BDELLOVIBRIO BACTERIOVORUS1
Authors: Burnham Jeffrey C. , Stetak Thomas , Locher Gregory 
Published: August 2007

SUMMARYWhen either cells of the bacterium, Bdellovibrio bacteriovorus (Stolp & Starr), strain 15143, or a heat‐resistant lytic factor derived from these cells is added to viable cultures of Phormidium luridum var. olivacea Boresch all the algal cells underwent gradual lysis. This effect was obtained with a mean initial bdellovibrio:algal cell ratio of 7.5:1. When P. luridum was mixed with the bdellovibrio cultures the algal chlorophyll content showed an 8‐fold decrease. Concomitantly, this interspecies interaction caused, a 75% inhibition of algal photosynthesis after‐4 h. Heat, treatment of the B. bacteriovorus culture supernatant fluid increased its ability to inhibit photosynthesis approximately 14%. Light, microscopy showed pale granules and intracellular spaces to form in the P. luridum within 16 h after adding the bdellovibrio lytic factor. Subsequent morphological changes included the development of large intracellular spaces, intercellular spaces, spheroplast formation and finally Complete lysis of the algal cells.
AN UNUSUAL METHOD FOR CULTURE OF UNICELLULAR MARINE ALGAE1
Authors: Ukeles Ravenna , Bishop Jean 
Published: August 2007

SUMMARYA method for the axenic culture of marine microscopic algae that utilizes various types of paper as solid substrates for growth is described. Investigations into the growth of 39 algal, strains on various paper substrates were conducted. Applications of the method to bioassay are discussed.
SEASONAL, SUCCESSION OF ALGAE IN RIVERS. I. EXAMPLES FROM THE AVON, A LARGE SLOW‐FLOWING RIVER1
Authors: Moore James W. 
Published: August 2007

SUMMARYThe epipelic, epilithic and epiphytic algae in a large slow‐flowing river (the Avon) situated in southern England usually exhibited a pronounced bloom during early spring probably in response, to increasing daylength. Although floods caused a reduction in the standing crop of most communities both through scouring action and possibly long‐term alteration of microhabitat, they also seemed essential for the renovation of sediment and, rock substrates after periods of rapid algal growth. Because of the attachment characteristics of the predominant epiphytic species, the community attached to Cladophora remained relatively unaffected by flooding. Water velocity may have been important in determining the species composition of some communities, particularly the epiphytic associations. Nutrients probably seldom limited development, but during part of the summer competition with planktonic diatoms for silicon appeared to limit attached algae. During the summer, large scale detachment (which greatly reduced algal density) apparently correlates with a high photosynthetic rate. Algal, numbers in the plankton occasionally decreased in response to a loss of buoyancy of the predominant species.
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

SUMMARYInformation 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

SUMMARYThe 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

SUMMARYUsing 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

SUMMARYScanning 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

SUMMARYThe 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

SUMMARYThree 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

ABSTRACTThe 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

ABSTRACTPart 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

ABSTRACTExtracts 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

ABSTRACTConcentrations 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

ABSTRACTAmphora 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

ABSTRACTApproximately 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.