bluuebunny/crossref_metadata_2025_split huggingface dataset:
PHOSPHATE UPTAKE KINETICS INEUGLENA GRACILIS(Z) (EUGLENOPHYCEAE) GROWN ON LIGHT/DARK CYCLES.' I. SYNCHRONIZED BATCH CULTURES1
Authors: Chisholm S. W. , Stross R. G. 
Published: August 2007

SUMMARYThe characteristics of phosphate uptake in synchronized populations ofEuglena gracilisKlebs (Z) were studied. The cells were grown autotrophically in batch culture and synchronized with a cycle of 14:10 LD.Incorporation of P was nonlinear with time for the first 2 h of incubation over a wide range of P concentrations and completely inhibited by darkness. The kinetics of P uptake as a function of P concentration were triphasic between 0 and 100 μM PO4, obeying Michaelis‐Menten kinetics over the 0–3 μM PO4range‐only. Uptake velocity increased linearly with, concentration above 3 μM PO4.The kinetics of P uptake varied with stage in the cell cycle. The half‐saturation constant for uptake at the lower concentrations oscillated between 0.7 and 2.8 μM PO4, reaching a peak immediately before the onset of cell division (beginning of the dark period).Vmaxwas largest in the middle of the light period, as was the slope of the linear portion of the kinetic pattern. Further analysis of the kinetics suggests that changes in this slope are responsible for the oscillation inKsvalues calculated for the lower concentrations. This analysis assumes 2 uptake mechanisms, one which saturates at low concentrations of phosphate, and one which is nonsaturable over the entire concentration range examined.
PHOSPHATE UPTAKE KINETICS IN EUGLENA GRACILIS (Z) (EUGLENOPHYCEAE) GROWN IN LIGHT/DARK CYCLES. II. PHASED PO4‐LIMITED CULTURES1
Authors: Chisholm S. W. , Stross R. G. 
Published: August 2007

SUMMARYThe characteristics of phosphate uptake and photosynthetic capacity were studied in P‐limited populations of Euglena gracilis Klebs (Z), using both P‐limited batch cultures in stationary phase and cyclostat cultures grown on 14:10 LD.P uptake obeyed Michaelis‐Menten kinetics between 0 and 150 μM PO4 under both growth conditions. The value of Vmax was 35% lower in the dark than in the light in the stationary phase cells. The value of K8 was not affected by light conditions, and uptake was completely inhibited in the presence of 1 mm KCN.P uptake (at 2.0 μM PO4) and photosynthetic capacity showed diel periodicity with peak rates occurring just before the beginning of the dark period for P uptake, and 8 h into the light period for photosynthetic capacity. Vmax for P uptake increased by a factor of 1.5 over the light period, whereas K8 remained constant at 1.4 μM PO4. These patterns were displayed by both nondividing stationary phase cells and populations in which less than a third of the cells divided each day, indicating that the rhythmicity is not coupled to cell division.
THE RELEASE, SETTLEMENT AND GERMINATION OF ZOOSPORES INCHORDA TOMENTOSA(PHAEOPHYCEAE, LAMINARIALES)1,2
Authors: Tolh Ronald 
Published: August 2007

SUMMARYDetails of zoospore germination inChorda tomentosaLyngb. are outlined. Uninucleate zoospores, when released are embedded in a mucilaginous mass of carbohydrate which dissolves and the biflagellate zoospores become motile. The long anterior flagellum is composed of a highly coiled terminal region and a rigid lower section bearing mastigonemes. The rigid, short posterior flagellum lacks mastigonemes. After initial contact by the tightly coiled region of the anterior flagellum, the zoospore draws itself to the substrate by flagellar resorbtion. After deposition of 3 wall layers the germling produces a germ tube. During this time the disc‐shaped chloroplast enlarges undergoing changes in shape. As the germ tubes reach ca. 15 μm they cease forward growth and swell at their tips. The majority of cytoplasm of the original zoospore moves into the tube. Just before the nucleus enters the tube, centriole replication occurs. Mitosis is presumed to take place somewhere in the germ tube so that at 24 h, 2‐celled gametophytes are produced.
SIMULTANEOUS ASSIMILATION OF AMMONIUM AND NITRATE BY GELIDIUM NUDIFRONS (GELIDIALES: RHODOPHYTA)1
Authors: Bird Kimon T. 
Published: August 2007

SUMMARYSimultaneous assimilation of NH4 and NO3 by Gelidium nudifrons Gardner was observed in culture experiments of 4 possible combinations of NH4 and NO3. The combinations tested were those in which the concentration of both N sources were in the range of 3.0–4.0 μg‐atN · l−1; both in the range of 0.5–1.0 μg‐atN · l−1; one in the 3.0–4.0 μg‐atN · l−1 range and the other in the 0.5–1.0 μg‐atN · l−1 range; and, visa versa. The data suggest that the pools of both NH4 and NO3 are simultaneously available for algal assimilation.
CHLOROPHYLL A VERSUS ADENOSINE TRIPHOSPHATE AS ALGAL BIOMASS INDICATORS IN LAKES1
Authors: Paerl Hans W. , Tilzer Max M. , Goldman Charles R. 
Published: August 2007

SUMMARYThe relation between phyloplankton chlorophyll a and adenosine triphosphate (ATP) was investigated during a yearly cycle in Lake Tahoe, California–Nevada, and a variety of North American and New Zealand lakes of ranging trophic state. Since cellular concentrations of ATP have been shown as acceptable indicators of live biomass among natural microbial populations, the ratio of chlorophyll a to cellular ATP reveals the extent of pigment production per unit biomass under diverse environmental conditions.In general, mixed systems, i.e., epilimnion of most lakes sampled, showed good consistency of cellular chlorophyll a:ATP ratios. Under thermally stratified conditions at Lake Tahoe extensive modifications of the ratio occurred, leading to a 10‐fold increase in the ratio at the bottom of the euphotic zone by late summer. Thus, the applicability of chlorophyll a as a quantitative algal biomass indicator is greatly restricted in lakes having thermally stratified euphotic zones.
THE DESMID GENERASPHAEROZOSMA, ONYCHONEMAANDTEILINGIA: AN HISTORICAL APPRAISAL1
Authors: Kirk William L. , Postek Michael T. , Cox Elenor R. 
Published: August 2007

SUMMARYThe taxonomic history of the desmid generaOnychonemaWallich,SphaerozosmaCorda andTeilingiaBourrelly is reviewed. In addition, Teiling's studies on asymmetry applied toOnychonemaandSphaerozosmaare considered. Observations based on SEM examination of one species each ofOnychonemaand ofSphaerozosmaare presented to show morphological differences. Finally, an appraisal of the taxonomic proposals by Telling and Bourrelly is given.
BIOCHEMICAL TAXONOMY OF MARINE PHYTOPLANKTON BY ELECTROPHORESIS OF ENZYMES. I. THE CENTRIC DIATOMS THALASSIOSIRA PSEUDONANA AND T. FLUVIATILIS1,2
Authors: Murphy Lynda S. , Guillard Robert R. L. 
Published: August 2007

SUMMARYDiatom systematics depends almost entirely upon structure of the silica shell. It is not known to what extent the taxonomic species, as defined by shell structure, corresponds to the genetic species—i.e., to the reproductively isolated population. As an approach to this problem, we report here a comparison of enzymes by electrophoresis. We have examined the genetic constitution of a number of clones of (presumably) the same species for each of 2 closely related, centric diatom species: Thalassiosira pseudonana Hasle and Heimdal and T. fluviatilis Hustedt. The 4 clones of T. fluviatilis form a distinct group, clearly separated from all the T. pseudonana clones. Within T. pseudonana, 4 estuarine clones and one reef clone form a group that is distinctly different from 4 oceanic clones. A single clone of T. pseudonana from the Continental Slope waters is intermediate between these 2 groups and probably shares genes with both groups, indicating that the 2 T. pseudonana groups are not genetically isolated. We conclude that i) within groups, isolates are closely related even though they originated from different continents; and, ii) T. pseudonana is subdivided into ecological races.
PRESCOTTIELLA, A NEW GENUS OF ASYMMETRICAL DESMIDS (CHLOROPHYCEAE)1
Authors: Bicudo Carlos E. M. 
Published: August 2007

SUMMARYBipolar asymmetry has been considered a morphological characteristic sufficient for differentiation of genera among the Desmidiaceae. Therefore, Micrasterias sudanensis Grönbl., Prowse & Scott, the only species of Micrasterias showing such asymmetry, is made the type of a new genus, Prescottiella, gen. nov.
STICTYOSIPHON SORIFERUS (PHAEOPHYTA, DICTYOSIPHONALES) FROM EASTERN NORTH AMERICA1
Authors: South G. Robin , Hooper Robert 
Published: August 2007

SUMMARYAlthough earlier North American records of Stictyosiphon soriferus (Reinke) Rosenvinge cannot he substantiated, the species is shown to be common in Newfoundland and is also reported from Nova Scotia. Plants are summer annuals and a component of ephemeral subtidal communities characteristic of suitable inlets and harbors. Only plurilocular reproductive organs are produced. In culture the life history of populations from both sides of the North Atlantic consists of a direct replication by asexual zoospores. A microscopic stage might occur in the field, and is presently known only from European cultures. In eastern Canada S. soriferus is readily distinguishable from S. tortilis (Rupr.) Reinke, S. subsimplex Holden and S. griffithsianus (Le Jol.) Holmes & Batters.
THE LIFE HISTORY OF COLEOCHAETE SCUTATA (CHLOROPHYCEAE) STUDIED BY A FEULGEN MICROSPECTROPHOTOMETRIC ANALYSIS OF THE DNA CYCLE1,2
Authors: Hopkins Archibald W. , McBride Gordon E. 
Published: August 2007

SUMMARYThe life history of Coleochaete scutata Bréb. was analyzed by Feulgen microspectrophotometry, a technique measuring DNA content in individual nuclei. By correlating nuclear DNA content with morphological structures or stages in the life history, changes in ploidy level are revealed.The microspectrophotometric study confirmed the earlier reports of a haploid vegetative thallus with mitotic division restricted primarily to the margin of the thallus. In the mitotic cycle the G1 (pre‐synthesis) phase is longer in duration than the synthesis find G2 (post‐synthesis) phases. Oogamous sexual reproduction results in resistant oospores which attain DNA levels of 2C 8C (1C being the DNA level of gamete nuclei).
NITRATE REDUCTASE ACTIVITY OF AMPHIDINIUM CARTERI AND CACHONINA NIEI (DINOPHYCEAE) IN BATCH CULTURE: DIEL PERIODICITY AND EFFECTS OF LIGHT INTENSITY AND AMMONIA1,2
Authors: Hersey Ronald L. , Swift Elijah 
Published: August 2007

SUMMARYThe activity of extracted NADH‐NO3− reductase was measured in the marine dinoflagellates Amphidinium carteri Hulburt and Cachonina niei Loeblich. Its activity showed a diel periodicity and was ca. twice as great at midday as at midnight. The enzyme activity was unstable, with an in vitro half‐life of 2–3 h. Values of enzyme activity were low or undetectable during lag phase but paralleled the instantaneous growth rate value during log phase. Nitrate reductase activity was not found in the stationary phase of growth, but additions of NO3− resulted in enzyme activity after 24h. When A. carteri was exposed to a series of light intensities for several weeks, the division rate and enzyme activity increased with increasing light intensity up to saturating intensities. In 6 h exposures, enzyme activity decreased with decreasing light intensities below light intensities saturating division rate. Additions of NH4+ (0.5–50 μm) to A. carteri cultures decreased the amount of extractable enzyme. The in vitro activity was not inhibited by similar NH+4 concentrations.
SIDEROCHROMES IN CYANOPHYCEAE: ISOLATION AND CHARACTERIZATION OF SCHIZOKINEN FROM ANABAENA SP.1
Authors: Simpson Frank B. , Neilands J. B. 
Published: August 2007

SUMMARYSchizokinen, a high affinity iron transport compound (siderochrome), previously described from Bacillus megaterium, has been isolated and characterized from low‐iron cultures of a bluegreen alga, Anabaena sp. No conclusive evidence for production of an iron‐repressible hydroxamate or catechol type siderochrome was observed in certain other bluegreen algae, such as Anabaena cylindrica Lemm., Coccochloris peniocystis (Kütz.) Drouet & Daily, Anacystis sp., Gloeocapsa alpicola (Lyng.) Born. or Chroococcus sp.
PHOSPHOTUNGSTIC ACID‐CHROMIC ACID: A SELECTIVE STAIN FOR ALGAL PLASMA MEMBRANES1,2
Authors: Sundberg Ingrid , Lembi Carole A. 
Published: August 2007

SUMMARYA phosphotungstic acid‐chromic acid mixture selectively stains the plasma membrane of whole cells of selected members of the Chlorophyceae, Charophyceae, Euglenophyceae, Xanthophyceae, Bacillariophyceae, Chrysophyceae, and Rhodophyceae, and the plasma membrane in cell‐free fractions of Mougeotia (Chlorophyceae). The procedure is not effective on the plasma membrane of the cyanophycean Scytonema or the cyanophycean endosymbiont of Glaucocystis. Staining of the cell walls of Chlamydomonas, Bangia, and Scytonema and the pellicle and sliding junction of Euglena and Astasia suggest that PTA‐CrO3 reactivity may be associated with glycoproteins in the cell walls and plasma membranes.
THE EFFECT OF SULFIDE ON THE BLUEGREEN ALGAE OF HOT SPRINGS. I. NEW ZEALAND AND ICELAND1
Authors: Castenholz Richard W. 
Published: August 2007

SUMMARYThe concentration of soluble sulfide (H2S, HS−, S=)2 in hot springs of New Zealand and Iceland has a “species‐determining” effect which appears to override the effect of all other chemical factors excepting hydrogen ion concentration. The cosmopolitan high‐temperature form (HTF) of Mastigocladus laminosus (Ag.) Cohn appears to be sensitive to concentrations of S= over 0.15 mg·l−1 in New Zealand and 0.25 mg·l−1 in Iceland. It was absent in thermal streams where S= level was high enough to exceed this concentration at a point below its optimal temperature range (i.e., below ca. 50 C). In low or non‐S= springs in these regions this alga formed mats to an upper temperature limit of 63–64 C.In contrast, one bluegreen alga (Oscillatoria amphigranulata van Goor) occurred abundantly only in moderate to high S= springs of New Zealand; this was a species with an upper temperature limit of about 57 C. Field 14C‐HCO3− incorporation experiments with various levels of added S= confirmed the sensitivity of HTF Mastigocladus and the great tolerance of O. amphigranulata. In the latter, the photosynthetic incorporation of 14C‐HCO3− was sustained or enhanced by the additions of S= in the presence of 5 × 10−5m DCMU, an inhibitor of photoelectron transport on the reducing side of photosystem II. It is possible, but not proven, that S= may act as a photoreductant in this species.
SYNCHRONIZATION OF THE MARINE DINOFLAGELLATEAMPHIDINIUM CARTERIIN DENSE CULTURES1
Authors: Galleron Colette 
Published: August 2007

SUMMARYUnder improved conditions,Amphidinium carteriHulburt can be obtained as dense cultures (5–9 × 105cells · ml−1) 5 days after inoculation. The possible association of a marine bacterium with the alga is discussed. A method to synchronize this photosynthetic organism is described which is based on the endogenous rhythm of division and the effect of light‐dark alternating periods.
BRACKISH WATER AND FRESHWATER SPECIES OF THE DIATOM GENUS SKELETONEMA. II. SKELETONEMA POTAMOS COMB. NOV.1
Authors: Hasle Grethe R. , Evensen Dale L. 
Published: August 2007

SUMMARYElectron microscope investigations of the siliceous frustule show that the diatom described by Hustedt as Stephanodiscus subsalsus (A. Cleve) Hust. is not Skeletonema subsalsum (A. Cleve) Bethge (Melosira subsalsa A. Cleve) but is Microsiphona potamos Weber. This species is so similar to Skeletonema costatum (Grev.) Cleve and Skeletonema subsalsum that the combination Skeletonema potamos (Weber) Hasle is suggested. Present records classify Skeletonema potamos as a freshwater species of lakes and rivers. In Sandusky Bay, Lake Erie (U.S.A.) and in River Wümme, a tributary of the River Weser (Germany) it grows with Skeletonema subsalsum. In nature, and when grown in cultures at a salinity of 0%, the processes are extremely short; when grown at salinities of 2% or more, the processes are much longer.
CHEMICAL ESTIMATIONS OF DNA CHANGES DURING SYNCHRONOUS GROWTH OFEUDORINA ELEGANS(CHLOROPHYCEAE)12
Authors: Lee K. A. , Kemp C. L. 
Published: August 2007

SUMMARYAnalysis of synchronous populations of Eudorina elegansEhrenberg revealsthat DNA replication occurs coincidentally with the very rapid sequence of cell divisions. The average doubling time for DNA in such synchronous populations is 40 min. The basal amount of DNA/E.eleganscell is estimated to be 0.5 × 10−12g.
SYNCHRONOUS GROWTH IN THE COLONIAL EUDORINA ELEGANS (CHLOROPHYCEAE)1,2
Authors: Kemp C. L. , Lee K. A. 
Published: August 2007

SUMMARY Eudorina elegans Ehrenberg has been synchronized by growing the organisms at 32 C in an enriched medium on a 16:8 LD cycle. Nuclear division occurred during the light period and 2–4 h was required, for the population to complete the sequence of 4 or 5 divisions each cell normally undergoes. Each cell division required 2–3 min with ca. 15 min as the intermitotic time. The sequence was repealed, every 24 h as long as synchrony was maintained.
STUDIES ON MARINE PLANKTON DIATOMS. II. RESTING SPORE MORPHOLOGY1
Authors: Hargraves Paul E. 
Published: August 2007

SUMMARYA morphological study of resting spores in five marine planktonic diatom species using electron microscopy indicates that Bacteriastrum delicatulum Cleve and Leptocylindrus danicus Cleve spores bear little resemblance, to their vegetative cells. Detonula confervacea (Cleve) Gran and Stephanopyxis turris (Grev. & Arn.) Ralfs spores have several features in common with their vegetative cells, and Rhizosolenia setigera Brightwell lies between the two extremes. The function of resting spores in relation to diatom life cycles is briefly discussed. Spore formation may be a primitive characteristic in the life cycle and may no longer have significant survival value for the species.
VAUCHERIA SYNANDRA (XANTHOPHYCEAE, VAUCHERIALES): FIRST RECORD FOR NORTH AMERICA1
Authors: Pecora Richard A. 
Published: August 2007

SUMMARYThe brackish water species, Vaucheria synandra Woronin, common to Europe, is reported for the first time in North America from a coastal swamp area in Louisiana. The material from Louisiana is described and pictured, and is compared to other Vaucheria species with androphores.
OOCARDIUM STRATUM A RARE (?) DESMID (CHLOROPHYCEAE)1
Authors: Lois A. Pfiester O.P. 
Published: August 2007

SUMMARYThe monotypic desmid, Oocardium stratum Nägeli is reported from calcareous stream. Because, of its unusual habitat, it is easily overlooked and is probably more common in occurrence than is reported.
ADAPTIVE PHOTOSYNTHESIS RESPONSES TO TEMPERATURE EXTREMES BY THE THERMOPHILIC CYANOPHYTESYNECHOCOCCUS LIVIDUS1
Authors: Sheridan Richard P. , Ulik Thomas 
Published: August 2007

SUMMARYThe physiological and biochemical changes associated with and resulting in adaptation to both sub‐ and supra‐optimal temperatures are presented for the thermophilic cyanophyteSynechococcus lividusCopeland. The optimum temperature for growth was 45 C. An increase in the optimum temperature of photosynthesis from 50 to 55 C was shown for cells grown at the supra‐optimum temperature of 57 C; whereas, cells grown at the sub‐optimal temperature of 35 C exhibited a decrease in the optimal temperature from 50 to 45 C for14CO2uptake. These changes in optimal temperatures are interpreted as adaptive. Associated with the 5 C increase in optimal temperature for photosynthesis was an increase in chlorophyll a, plastoquinone A, and activity of ribulose‐1,5‐diphosphate carboxylase (RuDP carboxylase). However, the increase in the temperature optimum for 57 C grown cells was associated with a reduced O2yield correlated with a reduced ferricyanide photoreduction capacity. RuDP carboxylase activity decreased rapidly above 55 C. Therefore reduced rates above 55 C resulted from damage to ferricyanide reducing systems and reduced RuDP‐carboxylase activity, whereas low photosynthesis rates at sub‐optimal temperatures were probably due to rate limiting effect of low temperatures on RuDP carboxylase activity with no evidence of damage to ferricyanide photoreducing systems.
ULTRASTRUCTURE DURING DEVELOPMENT OF THE NUCLEUS OF BATOPHORA OERSTEDII (CHLOROPHYTA; DASYCLADACEAE)1
Authors: Liddle Larry , Berger Sigrid , Schweiger Hans‐Georg 
Published: August 2007

SUMMARYThe primary nucleus of Batophora oerstedii J. Agardh like that of the related Acetabularia, undergoes a great increase in size throughout vegetative development. Formation of small secondary nuclei represents an irreversible stage in the development of reproductive structures in the gametangia. Changes observed in the course of the life cycle include: i) an increase from 3 to 200 μm diam, of the nucleus; ii) increase in number of nucleoli; iii) development of the perinuclear region; iv) increased pore density in the nuclear membrane; v) development of chromosomes in the nucleoplasm; vi) formation of secondary nuclei; and, vii) division of secondary nuclei.
SUN‐SHADE ECOTYPES OF A BLUEGREEN ALGA IN A HOT SPRING1,2
Authors: Sheridan Richard P. 
Published: August 2007

SUMMARYClone cultures of the thermophilic alga Plectonema notatum Schmidle were established from cells collected from the high and low light intensity regions of the algal mat which developed in Jerry Johnson Hot Spring, Idaho. Clones isolated from cither high, or low light intensify zones were grown at light intensities of 8000 and 400 ft‐c. The existence of specialized and genetically fixed sun or shade ecotypes was evidenced, by the ability of low light intensity clones to synthesize more light harvesting chlorophyll a when grown under low light conditions than the high light clones. High light clones showed light saturation of photosynthesis at higher light intensities with higher carboxylating enzyme activities and less chlorophyll a than low light clones when both were cultured at 8000 ft‐c. These clones displayed infraspecific variation along the light intensity gradient and therefore exist as a mosaic of light, intensity ecotypes.
STUDIES ON MARINE PLANKTON DIATOMS. III. STRUCTURE AND CLASSIFICATION OF GOSSLERIELLA TROPICA1
Authors: Hargraves Paul E. 
Published: August 2007

SUMMARYThe structure of the tropical oceanic diatom Gossleriella tropica Schütt was examined in the light and electron microscopes. The species is characterized by a primarily poroid valve, surface, it single central labiate process and a unique ring of spines attached to the cingulum. Placement of the genus in the family Rhizosoleniaceae is suggested. Although G. tropica is widely distributed in the world's oceans, it is usually confined to the lower photic zone, salinities of 34.5–35.5% and temperatures of 15–30 C.
THE BIOLOGY OF HARVEYELLA MIRABILIS (CRYPTONEMIALES; RHODOPHYCEAE). V. HOST RESPONSES FO PARASITE INFECTION1,2
Authors: Goff Lynda J. 
Published: August 2007

SUMMARYThe thallus of Harveyella mirabilis (Reinsch) Schmitz & Reinke is composed of vegetative rhizoidal cells growing intrusively between adjacent cells of the red algal hosts (Odonthalia and Rhodomela) and a protruding reproductive pustule. Although primarily composed of Harveyella cells, host medullary and cortical cells also occur in the emergent pustule. In both tissue regions, Harveyella cells are connected to host cells by secondary pit connections initiated by the host. Direct penetration of host cells by rhizoidal cells of Harveyella occasionally occurs, resulting in host cell death. Degeneration of host medullary cells beneath the pustule may result in a hollow branch and the cortical cells undergo cell division forming a thick palisade layer of randomly associated, photo‐synthetically active cells. It is within these branches that the parasite overwinters vegetatively. Host medullary and cortical cells dispersed in the emergent pustule show few of the degenerative responses noted in host cells adjacent to parasite rhizoidal cells. Rather, host cell division, chloroplast division and photosynthetic assimilation of H14CO−3 all increase. Spherical virus‐like solitary bodies (S‐bodies) occur in all Harveyella cells and in all host cells attached to Harveyella by secondary pit connections. The possibility that these structures may induce the infective response in the host is discussed.