bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE BENTHIC ALGAE OF SOUTHERN BAFFIN ISLAND. I. EPIPELIC COMMUNITIES IN RIVERS1
Authors: Moore J. W. 
Published: August 2007

SUMMARYThe epipelic algae found in 9 rivers of southern Baffin Island were investigated during the 1972 growing season. The overall assemblage consisted of 240 taxa, of which 200 belonged to the Bacillariophyta and, only 17 to the Chlorophyta. Members of the Bacillariophyta accounted for S7–100% by numbers and 44–100% by volume of the algae at most localities. The dominant taxa were Achnanthes kriegeri Krasske, A. marginulata Grun., and Tabellaria flocculosa (Roth.) Kütz. The Chlorophyta comprised. 0–7% by numbers and 0–30% by volume of the algae, with Cosmarium tinctum Ralfs, Cylindrocystis spp., and Mougeotia sp. being most common.The standing crop in the different rivers commonly exceeded 8 × 106 cells/cm2 (8 × 109μ3/cm2), and a maximum growth rate of 3.2 × 105 cells/cm2/day (3.2 × 108μ/cm2/day) was observed. Temperature and light are considered important, factors in the regulation of algal numbers, while nutrient supply in the overlying water, grazing by herbivores, wave action, and flooding appeared to have little effect.
RHAMNOCHRYSIS AESTUARINAE, A NEW MONOTYPIC GENUS OF BENTHIC MARINE CHRYSOPHYTES1
Authors: Wilce Robert T. , Markey Donald R. 
Published: August 2007

SUMMARYRhamnochrysis aestuarinae from Ipswich, Massachusetts, is a new species of benthic marine chrysophyta. Details are given describing its gross and fine structure morphology, its reproductive life history as understood from, both field and culture studies, and its ecology and probable systematic position in the Chrysomeridaceae (Sarcinochrysidales).
DNA SYNTHESIS IN CRYPTOTHECODINIUM COHNII1
Authors: Franker Colin K. , Sakhrani Lahki M. , Prichard Candyce D. , Lawden Carol A. 
Published: August 2007

SUMMARYThermal denaturation profiles of 32P‐labeled DNA obtained from synchronous cultures of Cryptothecodinium cohnii were examined by elution from hydroxyapatite over a temperature range of 65 to 99 C. The profile of uniformly labeled DNA from this organism shows at least 4 discrete components which elute after a temperature of 83 C is reached. These components from the “high melt” region of the profile appear to be synthesized during the latter one‐third of the S phase in synchronous culture.
THE FEEDING OF AMEBAE ON ALGAE IN CULTURE1
Authors: Ho Theresa S.‐S. , Alexander Martin 
Published: August 2007

SUMMARYAmebae differed greatly in their ability to prey on algae. Species of Chlamydomonas, Pandorina, Anabaena, Ourococcus, Ankistrodesmus, and Gloeocystis were utilized by 3 or all 4 of the test protozoa, while strains of Staurastrum and Chlorella would not support growth of the predators. Heating the cells of Chlorella sp. rendered them available to the 4 amebae and made Pandorina morum a better nutrient for some of the protozoa. Heating Chlamydomonas oblonga had no effect on its availability to Tetramituis rostratus and reduced its suitability as a food source for Amoeba discoides. The rate of protozoan feeding was also influenced by temperature, pH, and age of the algal prey.
MITOSIS, CYTOKINESIS, AND COLONY FORMATION IN THE GREEN ALGASORASTRUM1
Authors: Marchant Harvey J. 
Published: August 2007

SUMMARYSynchronous mitotic divisions produce multi‐nucleate cells ofSorastrum. Perinuclear envelopes of endoplasmic reticulum and a virtually intact nuclear envelope enclose mitotic nuclei. Cytoplasmic cleavage, which shirts before the last round of Synchronous mitoses, gives rise to uninucleate fragments which differentiate to form zoospores. These zoospores are released into a spherical vesicle, presumably derived from the inner layer of the parental cell wall, in which they swarm actively before aggregating as a spherical colony. The roughly conical shaped zoospores apparently adhere laterally before withdrawing their flagella and extending horns and a stipe, which, following wall deposition, interconnects the cells at the center of the colony. The probable role of the microtubules, which underlie the plasmalemma of aggregating cells, in determining the shape of both the cells and the colony itself is discussed.
TOXICITY OF THE PESTICIDE ZECTRAN ON PHOTOSYNTHESIS, RESPIRATION, AND GROWTH IN FOUR ALGAE1,2
Authors: Snyder C. E. , Sheridan R. P. 
Published: August 2007

SUMMARYThe insecticide Zectran decreased both respiration and photosynthesis in Oscillatoria terebriformis and Synechococcus lividus at concentrations between 0.5 and 12.5 ppm, whereas Navicula pelliculosa and Scenedesmus quadricauda were, relatively unaffected by these, same concentrations in the short‐term, manometric experiments. In long‐term growth experiments all 4 species exhibited a toxicity threshold between 1 and 10 ppm Zectran.
CELL DIVISION INBULBOCHAETE.II. HAIR CELL FORMATION1
Authors: Pickett‐Heaps Jeremy D. 
Published: August 2007

SUMMARYMost vegetative cells ofBulbochaete, and all those ofOedogonium, possess an apical, circular discontinuity in the structure of their secondary wall. Rupture of the wall at this precise site permits expansion of the ring during cell division and release of the zoospore following zoosporogenesis. Certain cells ofBulbochaete(always the apical daughter cell of a division pair) lack this type of discontinuity. Instead, the apical wall is thinned out on one side, so that the cell bulges asymmetrically. In the middle of the bulge is a wall discontinuity which extends only part way around the cell. The wall will rupture here, too, for zoospore release, but if a cell having such a wall, divides, it invariably does so asymmetrically, with one pole of the spindle located in the bulge. Cytokinesis then cuts off a small, colorless daughter cell. The wall ruptures at the discontinuity, and this daughter cell emerges through the slit and differentiates into a hair.The creation of hairs in such cells commences with the deposition of a pad of primary wall lining the bulge. Golgi bodies are involved in its secretion, but not in that of a secondary wall layer which forms next in the premitotic cell and covers the primary wall. The cell becomes polarized; the nucleus migrates toward this region as the chloroplast moves aside. After the asymmetric mitosis, a curved phycoplast cuts off the hair cell nucleus and prevents the chloroplast from moving back into the future hair, whose cytoplasm soon loses much of its affinity for heavy metal stains. Following rupture of the parental wall, the phycoplast moves some distance past the limits of the newly deposited secondary wall layer and then forms a cross wall under the hair.The secondary wall of the hair isnotcontinuous with the secondary wall structure of the parental cell; the circular discontinuity that arises around the base of the bulging parental wall is then perpetuated and accentuated as the hair's secondary wall thickens. This wall weakening becomes the dislocation that will predetermine the site of the ring and consequently the direction of cell expansion in the next normal division of the cell subtending the hair. Abnormal ring formation and the creation of terminal twin hairs have also been examined. The lip of the growing hair contains a characteristic organization of membranes and other components which may be related to the organization of the hair's numerous longitudinally oriented microtubules.These results are discussed in terms of the morphology of the wall in the Oedogionales generally. The creation of the special wall morphology that leads to hair cell formation is considered to be ontogenetically related to a similar wall morphology that is involved in formation of the fertilization pore of the oogonium.
NUTRIENT UPTAKE KINETICS IN PHYTOPLANKTON: A BASIS FOR NICHE SEPARATION1
Authors: Stross R. G. , Pemrick S. M. 
Published: August 2007

SUMMARYDaily patterns of incorporation of carbon dioxide and inorganic phosphate were measured in phytoplankton from Lake George, New York, in January and February 1972. Rates of photosynthesis oscillated in phase for the entire assemblage and for individual cells of the diatoms Asterionella, Tabellaria, and Fragilaria. The photosynthetic capacity was maximal in the early afternoon.Daily patterns of phosphate uptake were also rhythmic. At ambient concentrations the assemblage takes up phosphate maximally in the morning while individual cells of the large diatom take it up maximally in the evening.A kinetic analysis of phosphate uptake indicated 2 velocities of uptake for cells of Tabellaria and Fragilaria: a hyperbolic function at small and an apparently linear relationship at relatively large concentrations. The large diatoms, in contrast to the total assemblage, functioned maximally at 2 separate times of the day: in the evening at ambient levels and in the morning at 0.4 μM and larger concentrations.Temporal stratification of the nutrient niche may be achieved by several uptake mechanisms in the algal cell that function at different times of the day or with a variable uptake velocity.
THE EFFECT OF LIGHT QUALITY ON THE CARBON METABOLISM AND EXTRACELLULAR RELEASE OF CHLAMYDOMONAS REINHARDTII DANGEARD1
Authors: Brown T. J. , Geen G. H. 
Published: August 2007

SUMMARYThe influence of red, blue, green, and white light on growth and photosynthetic rates, carbon metabolism, and rates of release of extracellular compounds in the freshwater alga Chlamydomonas reinhardtii Dangeard was examined. Relative growth constants were 0.28, 0.32, 0.40, and 0.41 in green, white, blue, and red light, respectively. Photosynthetic rates were higher in white, blue, or red than in green light of the same intensity.More than 66% of the 14CO2 assimilated by cells grown under blue or green light was incorporated into the ethanol‐insoluble fraction, compared with about 50% in cells grown under white or red light. The percentage of sugars in this fraction was significantly higher in cells grown under green or red light than in cells cultured in white or blue light, while the percentage of proteins was highest in blue light. Light quality also influenced the composition of the ethanol‐soluble fraction. The percentage of organic acids was highest in cells grown in green and white light, while amino acids were highest in blue and green cultures. The percentage of ethanol‐soluble sugars was greatest in cultures grown in blue and red light.The percentage release of dissolved organic carbon into the medium was highest in white light and lowest in blue or red light. The nature of the extracellular products varied according to the quality of light under which the cells were cultured, but had no consistent relation to the nature or concentration or components in the ethanol‐soluble fraction.
AN IMPROVED METHOD FOR OBTAINING AXENIC CLONES OF PLANKTONIC BLUE‐GREEN ALGAE1,2
Authors: Carmichael Wayne W. , Gorham Paul R. 
Published: August 2007

SUMMARYAxenic clones from 5 isolates of Anabaena flosaquae, 1 isolate of Microcystis acruginosa, and 1 isolate of Aphanizomenon flos‐aquae were obtained by a combination of steps that provided a 1000‐fold reduction in the bacteria‐algae ratio and permitted bacteria‐free filaments or cells to be isolated and grown from agar pour plates. The first step consisted of the addition of phenol to a dark‐treated culture to selectively reduce the numbers of actively growing bacteria while leaving the resting algal cells viable. The next steps involved washing the treated algal suspension on a Millipore filter pad or membrane followed by plating in washed agar containing buffered mineral medium plus vitamins and soil extract. The final steps consisted of incubating the agar pour plates, coring bacteria‐free filaments or cells, culturing the agar cores in a buffered mineral medium, and rigorously testing the resulting cultures for bacteriological contamination. Between 50 and 90% of the cores grew, and of these about 50% were judged axenic. The method, with appropriate adaptations, should be suitable for obtaining axenic clones of other freshwater and marine algae.
GROWTH OF VITAMIN B12‐REQUIRING MARINE DIATOMS IN MIXED LABORATORY CULTURES WITH VITAMIN B12‐PRODUCING MARINE BACTERIA12
Authors: Haines Kenneth C. , Guillard Robert R. L. 
Published: August 2007

SUMMARYThe vitamin B12requirement of several marine diatoms can be satisfied in B12−limited laboratory cultures by heterotrophic marine bacteria isolated from the same waters and from sediments. The bacteria can utilize diatom excretory products, or the remains of dead diatom cells, in the production of the vitamin.The growth of 12 B121− requiring diatoms (7 genera) in mixed cultures with 14 different bacteria (without added B12) was compared to the growth of those same diatoms in axenic cultures with excess added B12. Diatom growth was generally rapid in the first few days, followed by sustained, slower growth. The diatom yields in mixed cultures ranged from 0.8 to 84% of the yields in axenic cultures with added B12.In a detailed study of one mixed culture, increases in diatom densities were paralleled by increases in cell densities of the bacterium during the first few days of exponential diatom growth. During the period of slow diatom growth, when diatom densities oscillated but steadily increased, the decreases in diatom densities were associated with increased bacterial growth. This suggests that death of a fraction of the B12‐limited diatom population releases sufficient organic matter to stimulate growth of the bacteria and their subsequent excretion of B12; this B12in turn stimulates further growth of the diatoms.Diatom‐bacteria interactions leading to the production of B12may be important in maintaining viable populations of B12‐requiring diatoms in nutrient‐poor waters during periods between blooms, when conditions are unfavorable for rapid growth.
OCCURRENCE OF CHOLINE ESTERS IN THE MARINE DINOFLAGELLATE AMPHIDINIUM CARTERI12
Authors: Taylor Richard F. , Ikawa Miyoshi , Sasner John J. , Thurberg Frederick P. , Andersen Kenneth K. 
Published: August 2007

SUMMARYAcrylylcholine, choline O‐sulfate, and a yet unidentified choline ester have been isolated from cells of Amphidinium carteri. Natural and synthetic acrylyl choline had approximately 1/4,000 the activity of acetylcholine and choline O‐sulfate about 1/20,000 the activity on isolated Mercenaria mercenaria heart.
SOME ASPECTS OF PHOTOSYNTHESIS IN CLADOPHORA GLOMERATA1
Authors: Mantai Kenneth E. 
Published: August 2007

SUMMARYPhotosynthetic rates in field‐collected samples of Cladophora glomerata were measured using the oxygen electrode technique. Rates observed were three‐ to fourfold higher than literature values obtained with the light and dark bottle method. The discrepancy appears to be due to light‐limiting conditions prevailing in the bottles. It was also found that photosynthesis in Cladophora does not saturate at low light intensities as reported by other workers.
LE PLASTIDOME CHEZ EUGLENA GRACILIS Z1
Authors: et R. Calvayrac A.‐M. Orcival‐Lafont 
Published: August 2007

SUMMARYChloroplast morphology changes cyclically during each cell generation of synchronous photoheterotrophic cultures of Euglena gracilis Z; these cycles persist until the transition to stationary phase. Structural modifications, development of pyrenoids, and increase in chloroplast volume accompany the cessation of cell division. Chloroplasts of stationary phase heterotrophic cells resemble those of exponential phase autotrophic cells, suggesting a relationship between chloroplast morphology and available carbon.
CHLOROPLAST INCLUSIONS IN ZOOSPORES OF OEDOCLADIUM1
Authors: Markowitz Melvin M. , Hoffman Larry R. 
Published: August 2007

SUMMARYChloroplast inclusions have been studied in zoospores of Oedocladium carolinianum and their ultrastructure compared with the same inclusions previously described in the related genera Oedogonium and Bulbochaete. Structure of the mature pyrenoids is consistent in all 3 genera; the pyrenoid matrix is penetrated by branched cytoplasmic channels delimited by a double membrane system continuous with the chloroplast envelope. Pyrenoids typically arise de novo in zoospores of O. carolinianum. No evidence for the bipartition of a parent pyrenoid has been observed. The incipient pyrenoids of Oedocladium are similar to those found in zoospores of Oedogonium and Bulbochaete, but they frequently demonstrated a crystalline matrix. However, a crystalline matrix was never observed in any mature pyrenoid, even those immediately adjacent to incipient pyrenoids with crystalline structure. Other chloroplast inclusions typical of Oedogonium and Bulbochaete zoospores are the eyespot and striated microtubules. Although the zoospores of O. carolinianum possess striated microtubules, the presence of an eyespot has not been observed.
MITOSIS AND CYTOKINESIS IN THE CHLOROMONADOPHYCEAN ALGAGONYOSTOMUM SEMEN1
Authors: Heywood Peter 
Published: August 2007

SUMMARYMitosis and cytokinesis inGonyostomum semen(Ehrenberg) Diesing have been investigated with the light microscope. During prophase nucleoli disappear and the chromatid structure of the chromosomes becomes apparent. Separation of chromatids at anaphase is accompanied by progressive fusion of the progeny chromosomes. This process continues into telophase by which stage the progeny nuclei consist of dense masses of chromatin with occasional chromosomes extending from their equatorial surfaces. By the end of telophase, nucleoli are reforming and the interphase nuclear morphology is reestablished. Mitosis is followed by cytokinesis, which is a relatively lengthy phase. In early cytokinesis the 2 interphase nuclei are present, and there is no indication of the forthcoming division of the cytoplasm. Later in cytokinesis a membrane is formed between the 2 nuclei. Final separation of the progeny individuals is accomplished by vigorous movements of swimming cells or, in the case of palmelloid cells, by the deposition of a mucilaginous layer.
VAUCHERIAE OF NORTH CAROLINA. I. MARINE AND BRACKISH WATER SPECIES1
Authors: Ott Donald W. , Hommersand Max H. 
Published: August 2007

SUMMARYMarine Vaucheriae of North Carolina were investigated in the field and in culture for 4 years. Of the 11 species collected, 4 are new records for North Carolina and 2 are previously unreported species. A new section is established, Acrandrae, to contain Vaucheria acrandra sp. nov. and Vaucheria adela sp. nov. The diagnostic character of the new section is the production of androphores directly from the terminal portion of the main filament rather than from a special cell produced laterally on the filament as in the section Androphorae.
GROWTH OF VITAMIN B12‐LIMITED CULTURES: THALASSIOSIRA PSEUDONANA, MONOCHRYSIS LUTHERI, AND ISOCHRYSIS GALBANA1,2
Authors: Swift Dorothy G. , Taylor W. Rowland 
Published: August 2007

SUMMARYThe growth rates of 3 species of phytoplankton were found to be dependent on the vitamin B12 concentrations in the media. In batch cultures, the vitamin B12 half‐saturation constants and standard errors were 0.39 ± 0.042 μμg/ml for Thalassiosira pseudonana (clone 3H), 1.69 ± 0.24 μμg/ml for Isochrysis galbana, and 2.77 ± 1.65 μμg/ml for Monochrysis lutheri. A chemostat was used to grow T. pseudonana with vitamin B12 as the controlling factor. In the chemostat the yield and standard deviation, 102 ± 21 × 104 cells/μμg vitamin B12, was the same as in the batch culture, 126 ± 13 ± 104 cells/μμg. The chemostat half‐saturation constant, 0.26 ± 0.068 μμg/ml vitamin B12, and maximum growth rate were in agreement with those obtained in batch cultures. Vitamin concentrations for maximum growth, rates were greater than those calculated necessary from yield data to give observed population densities similar to those in natural waters. In the sea the effect of vitamin B12 concentration on growth rates may be complicated by low concentrations of other nutrients or the presence of inhibitors.
STUDIES ON THE MARINE ALGAL FLORA OF VENEZUELA. V. PSEUDOGLOIOPHLOEA HALLIAE1,2
Authors: Ganesan E. K. 
Published: August 2007

SUMMARYDetails of structure and reproduction, particularly pre‐ and postfertilization development, are given for the first time in Pseudogloiophloea halliae. In general, the author's observations agree with what is known for most species of the genus. Some remarks on the identity of 3 species of Pseudogloiophloea in the tropical and subtropical American Atlantic shores are also included.
DENSITY‐DEPENDENT VERTICAL MIGRATION IN THE FRESHWATER DINOFLAGELLATEPERIDINIUM PENARDII(LEMM.) LEMM. FO.CALIFORNICUMJAVORN.1,2
Authors: Sibley Thomas H. , Herrgesell Perry L. , Knight Allen W. 
Published: August 2007

SUMMARYThe freshwater dinoflagellatePeridininm penardii(Lemm.) Lemm. fo.californicumJavorn. has a positively phototactic diel migration. The extent of migration seems to vary with population density.
THE FINE STRUCTURE OF THE FLAGELLAR APPARATUS OF CARTERIA1,2
Authors: Lembi Carole A. 
Published: August 2007

SUMMARYThe fine structure of the flagellar apparatus of 5 species of the green quadriflagellate alga Carteria is described. The 5 species can be morphologically separated into 2 groups on the bases of cell shape and ultrastructure of the pyrenoid and flagellar apparatus. Group I cells are spherical, possess many pyrenoid thylakoids, and retain a flagellar apparatus similar to that of Chlamydomonas reinhardi. The flagellar bases are oriented at approximately 90° to one another, have distal and proximal fibers, and are associated with 4 cruciately arranged microtubule bands. Cells of group II are ellipsoid, possess few pyrenoid thylakoids, and show a complex system of microtubule bands and sigmoid‐shaped, electron dense rods which extend between opposite pairs of basal bodies. The basal bodies of group II cells are directed inward in a circular pattern rather than outward as in group I cells. Unlike Chlamydomonas, the distal fiber of the Carteria species is nonstriated. The proximal fiber is striated, and both distal and proximal fibers are composed of 60–80 Å diameter microfibrils.