bluuebunny/crossref_metadata_2025_split huggingface dataset:
PARASITISM OF ASTERIONELLA FORMOSA HASS. BY A CHYTRID IN TWO LAKES OF THE RAWAH WILD AREA OF COLORADO1
Authors: Koob Derry D. 
Published: March 2008

SUMMARY The populations of Asterionella formosa Hass. in two subalpine lakes in the Rawah Wild Area, Colorado, were composed of colonies of five distinct size classes Based on frustule length. The spring bloom in these two lakes was dominated by cells of the Beta or Gamma population, whereas the fall pulse was dominated by cells of the Alpha and Beta, or Alpha populations. The Beta population was physiologically unique in that it was parasitized by the chytrid Rhizophidium planktonicum Canter. The development of the parasite population could not be correlated with the concentration or the growth phase of the host population. The occurrence of parasitism did not noticeably affect the population growth patterns of the Asterionella populations.
LOLA ZRREGULARIS (CHLOROPHYTA‐CLADOPHORACEAE): A NEW SPECIES FROM THE ROSS SEA, ANTARCTICA1
Authors: Zaneveld Jacques S. 
Published: March 2008

SUMMARY A small, loose lying, unbranched, filamentous alga from the Ross Sea, Antarctica, is described as a new species, Lola irregularis. The genus Lola is closely related to the genera Hormiscia, Rhizoclonium, and Chaetomorpha in the family Cladophoraceae. A key to all known species of Lola is included. This is the first record of a species of Lola south of the Antarctic convergence.
GLUTAMINE SYNTHETASE ASE ACTYVITY IN IN CHAETOCEROS AFFINIS (BACILLARIOPHYCEAE): COMPARISON WITH OTHER ESTIMATES OF NITROGEN UTILIZATION DURING NUTRIENT PERTURBATION1
Authors: Slawyk Gerd , Rodier Martine 
Published: March 2008

ABSTRACT Glutamine synthftase (GS) activity was investigated in a nitratt limited continuous culture of the marine diatom Chaeloccros afTinis (Lauder) Hustedt before and after the perturbation of the culture medium with 10 μM of 15 N labelled nitrate. Parallel studies were carried out on nitrate reductase(NR). nitrate uptake and assimilation, and Ievels of cellular nitrogen containing compounds with the objective to determine the validity of the GS assay as a measure of nitrate utilization. Activities in N‐deficient cells, grown at steady state, correlated well with uptake and assimilation rates. In N‐sufftcient celts, however, during the nitrate pertirbation period, they accounted only for about 10% of the two latter rates, when ambient nitrate concentrations were high (0. 7‐10 μ). It is proposed that under these growth conditions an alternative pathway via glutamate dehydrogenase (GDH) was operative. At low ambient nitrate concentrations (0.1‐0.7 μM), GS activities, uptake and assimilation rates again balanced rather well. Thus, the data support the view that GDH activity is associated with high levels and GS with low levels of external or internal nitrogen.
PARAMYLONSYNTHESISAND CHLOROPLAST STRUCTURE ASSOCIATEED WITH NUTRIENTLEVELSINEuUGLENA(EUGLENOPHYCEAE)1
Authors: Kiss John Z. , Vasoconcelos Aurea C. , Triemer Richard E. 
Published: March 2008

ABSTRACTA System has been developed to study the photoheterotrophic synthesis of paramylon, a β‐1,3 glucan storage product found in the euglenoid flagellates. The amount of paramylon in the cells is controlled by manipulating the levels of nutrients in the culture medium. During experimental conditions, when cells are transferred from an incomplete to a complete medium, the transferred from an incomplete to a complete medium, the paramylon concentration increases at least seven‐fold relative to the controls. Electron microscopic studies demonstrate that the pyrenoid disperses concomitantly with the period of paramylon increase. The pyrenoid of Euglena is labeled by a ribulose‐1,5 bisphosphate carboxylase‐oxygenase(Ru‐BisCO)antibody. The distribution of ruBisCO in the clocrplast is directly related to pyrenoid dispersal.
EFFECTS OF TEMPERATURE, SALINITY, IRRADIANCE AND DIURNAL PERIODICITY ON GROWTH AND PHOTOSYNTHESIS IN THE DIATOM NITZSCHIA AMERICANA; LIGHT‐SATURATED GROWTH1
Authors: Miller Richard L. , Kamykowski Daniel L. 
Published: March 2008

ABSTRACTThe physiological response of an estuarine clone of Nitzschia americana Fryx3ell was measured under experimental conditions of temperature and salinity which represent the average range of these variables in the Cape Fear River Estuary, North Carolina. The influence of temperature (10, 15, 20, 25, 30°C) and salinity (8, 15, 20, 26, 32‰) on specific growth rates, μ, and parameters of photosynthesis‐irradiance curves, α, and Pmax were measured during maximum and minimum rates of diurnal photosynthesis using axenic semi‐continuous batch cultures maintained at an irradiance saturating for photosynthesis (140 μE m‐2·s‐1). There was an increase in μ with increasing temperature up to a broad uptimum (25 ± 2.5°C), above which μ gradually declined. At the predicted optimum temperature of 25°C, μ increased as a linear function of salinity. oth light‐limited (α) amd light‐saturated (Pmax) rates of photosynthesis increased as salinity decreased. The effect of temperature on a and Pmax was complex and dependent on salinity. Pmax exhibited a diurnal periodicity, whereas estimates of a were not significantly different between sampling periods. Growth efficiencey opf N. americana, calculated as the ratio between specific growth rates and rates of gross photosynthesis, increased with an increase in salinity with a maximum at the predicted optimum temperature and salinity of 25°C and 32‰, suggesting and uncoupling between photosynthesis and growth at nonoptimum growth conditions.
FLAGELLAR DEVELOPMENT AND REGENERATION IN VOLVOX CARTERI (CHLOROPHYTA)1
Authors: Coggin Steven J. , Kochert Gary 
Published: March 2008

ABSTRACT The biflagellate somatic cells of Volvox carteri f. nagariensis lyengar exhibit an asymmetric pattern of flagellar development. Initiallt each somatic cell has two short (4 μm) flagella but after several hours one flagellum on each cell elongates unitl it reaches a length of 12 μm. Due to the regular arrangement of somatic cells in the Volvox spheroid it is apparent that the same flagellum on each somatic is the first to elongale. The asymmetric flagellar length is maintained for about 8 h after which the second flagellum on each somatic cell elongates. When the second flagellum attains the same length (12 μm) as the first flagellum, both flagella elongale at the same rate until reaching a final length of 22 μm. Experimental removal of somatic cell flagella results in their regeneration. Somatis cells regenerate both flagella simultaneously and full length flagella are produced in about 2 h. The intial rate of flagellar regeneration is about ten times faster than the intial rate of flagllar growth in development. Cycloheximide, an inhibitor of protein synthesis, has no effect on the initial rate of flagellar regeneration but the flagella produced in the presence of the drug are half the length of flagella produced in its absence. Somatic cells are able to regenerate flagella up to the time of α and β tubulin, the major structural proteins of the flagellar axoneme, and other cellular proteins.
DIATOM MINERALIZATION OF SILICIC ACID. VIII. METABOLIC REQUIREMENTS AND THE TIMING OF PROTEIN SYNTHESIS1
Authors: Blank Gregory S. , Robinson Dale H. , Sullivan Cornelius W. 
Published: March 2008

ABSTRACT We have examined the influence of temperature, protein synthesis, and energy metabolism on the process of silicon biomineralization in synchronized cultures of the diatom Navicula saprophilia Lange‐Bertalot & Bonik (1976). Temperature effects on silicon polymerization were compared in vitro and in vivo. In vivo incorporation was very temperature dependent with a Q10 of 7.53. In contrast, the Q10 for in vitro polymerization was 1.42, indicating much lower temperature dependence. This difference in Q10 values suggests that in vivo polymerization involves more than autopolycondensation. Cycloheximide addition to synchronized cultures up to, but not later than one hour after the addition of silicic acid depressed total uptake, incorporation, but not pool size. Developing valves demonstrated morphological abnormalities with cycloheximide additions from 0 to 2 h following silicic acid addition. These data suggest that de nova proteins are required in biomineralization and that they are synthesized during or just after cytokinesis. Biomineralization is not coupled to energy derived directly from photosystem II or photosynthesis, since neither darkness nor DCMU had an effect on any aspect of silicification.
DUDRESNAYA PUERTORICENSIS SP. NOV. (DUMONTIACEAE, GIGARTINALES, RHODOPHYTA)1
Authors: Searles Richard B. , Ballantine David L. 
Published: March 2008

ABSTRACT A new species of Dudresnaya is described from Puerto Rico and Georgia. Gametophytes have cylindrical axes, exserted apical cells, rectangular to hexagonal crystals in the axial cells, ellipsoidal outer assimilatory cells, spermatangial mother cells which are terminal or subterminal cells of the subdichotomously branched outer assimilatory branches and auxiliary cells which are indistinguishable in appearance from adjacent, large, deeply staining cells of the auxiliary cell branch. Tetrasporophytes are unknown.
ON THE MALE CONCEPTACLES OF TWO TERETE SPECCIES OF GRACILARIA(RHODOPHYTA, GIGGARTINALES)FROM NORTH CAROLINA1
Authors: Reading Richard P. , Schneider Craig W. 
Published: March 2008

ABSTRACTInspired by the description of the spermatangial conceptacles in Gracilaria blodgettii Harvey from the Asian Paacific as a continuum form the Textorii‐type of the Verruccosa‐type, a reinvestiagation of male plants of that species from North Carolina reveals unifform Textorii‐type con cepptacles. A male specimen of what has been called G. verrucosa (Hudson) Papenffuss i North Carolina does, however, shour a continuum between the two morphological types. Other ccharacteristics are given and questions are raised concerning the use of the specific epithet. G. blodgettii, in areas outside of the western Atlantic.
ANNUAL GERMINATION WINFOW IN OOSPORES OF NITELLA FURCATA (CHAROPHYCEAE)1
Authors: Sokol Roger C. , Stross Raymond G. 
Published: March 2008

ABSTRACT Oospores of Nitella furcata subsp. megacarpa (Allen emend. Wood) were collected from an oospore bank in the sediments of Lake George, New York. Incubated at constant temperatures, all or nearly all of the oospores germinated when exposed to a brief pulse of red light when the annual window of germinability was open. The window seems related to the annual cycle of sediment temperatures. It is open in spring and closes wit the onset of a secondary dormacncy in the summer. Oospores in storage follow a parallel path if held at 18°C, a summer equivalent temperature; the window remains open indefinitely if the oospores are held at 4°C. Attention is drawn to the similarity if the cyclic window of germinability in seeds of summer annuals and oospores of N. furcata.
COMPARATIVE STUDIES ON THE CELL WALLS OF SEXUAL AND ASEXUAL BANGIA ATROPURPUREA (RHODOPHYTA). II ELECTROPHORETIC PATTERNS OF POLYSACCHARIDES1
Authors: Cole Kathleen M. , Park Carol M. , Reid Philip E. , Sheath Robert G. 
Published: March 2008

ABSTRACT Cellulose acetate electrophoresis of the hot water soluble polysaccharide extracts from whole filaments, as well as base, mid and tip segments, of marine asexual and sexual Bangia atropurpurea (Roth) C. Ag. Yielded distinctive patterns which demonstrated that changes occur in the outer cell walls during sexual reproduction. Heterogeneity of the sulfated polysaccharide components isolated from outer cell walls was shown to be specifically related to sexual reproduction. Two components (Band I and II) were detected in extracts from tips of sexual filaments, whole only one (Band I) was present in the vegetative segments of all filaments and in asexual reproductive regions. The faster running component (Band II) was detected during the later stages of sexual development, prior to maturation.
POPULATION DYNAMICS OF THE SPORE‐FORMING DIATOM LEPTOCYLINDRUS DANICUS IN NARRAGANSETT BAY. RHODE ISLAND1
Authors: French Fred W. , Hargraves Paul E. 
Published: March 2008

ABSTRACT A field study to assess resting spore importance in long‐and short‐term population dynamics of Leptocylindrus danicus (Ehr.) Gran was carried out, based on the observation that germinating spores produce only vegelative cells of maximum diameter. From May through November 1978. L. danicus was present in lower Narragansett Bay, but resting spores were not found. May and June bioassays suggest that Bay water could not support sexuality (hence spore formation) in L. danicus during this period. Mean valve diameter decreased abruptly in early June. as did cell number. When mean valve diameter increased abruptly in August, with no resting spores seen, 70 additional clonal isolates showed that one clone had the “normal” sexual and spore‐forming life cycle while 69 clones had an “alternate” life cycle lacking sperm and spore formation. Valvar fine structure of the two types differed with respect to the presence or absence of a subcentral valvar pore, and a new subspecific taxon is here distinguished: variety apora. Examination of the early June data indicates the replacement of one population by another. Populations of L. danicus may be sporadically introduced into Narragansett Bay from Gulf Stream rings.
FLUORESCENCE INDUCTION AND PHOTOSYNTHETIC RESPONSES OF ARCTIC ICE ALGAE TO SAMPLE TREATMENT AND SALINITY1
Authors: Bates Stephen S. , Cota Glenn F. 
Published: March 2008

ABSTRACT The measurement of Photosynthetic rates of algae growing on the undersurface of 1. 7 m thick ice in the Canadian Arctic (Resolute Passage. N.W.T.) presents several problems. During the preparation of samples for physiological measurements, the ice algae may he exposed to salinity and temperature shocks. Fluorescence induction (the rise in in vivo Chl a fluorescence intensity during a period of millineconds) and photosynthesis‐irradiance (PI) experiments examined the potential effects of salinity and temperature on the physiology of ice algae. Experimental suspensions were routinely prepared by scraping one part ire crystals (11–14%0 salinity) and attached algae from the bottom ice into four parts filtered seawater (32%0 salinity). giving a final salinity of 28–31%0. Post‐dilution of melted ice scrapings with seawater suppressed photosynthetic 14C‐fixation and decreased ADCMU (the area above the fluorescence induction curve measured in the presence of the inhibitor DCMC: an estimate of photosynthetic capacity) by a factor of 3–16. due to the low salinity of the melted ice scrapings. Fluorescence induction and PI experiments showed that the ice algae had a salinity optimum near 30%0, close to the ambient seawater salinity, Experiments in which the Chl a concentration was manipulated showed that ADCMU, Pam (Chl a‐normalized rate of photosynthesis at light saturation), and a (photosynthetic efficiency) declined with increasing Chl a concentration. Ice algae tolerated heating (l.5°C‐min‐1) up to 17° C, above which ADCMU’decreased with sample temperature.
CRYPTOENDOLITHIC ALGAL COMMUNITIES OF THE COLORADO PLATEAU1
Authors: Bell Robert A. , Athey Patrick V. , Sommerfeld Milton R. 
Published: March 2008

ABSTRACT Eighteen taxa, including representatives of both eukaryotic and prokaryotic genera, were isolated from below the surface of eight sandstones in four semi‐desert and cold temperate biomes of northern Arizona, southern Utah and Western New Mexico. The algae occurred as uniform well defined bands in light‐colored sandstones and also as scattered patches in dark sandstones. The algal communities varied in generic composition, chlorophyll a content, and location within the different sandstones. Biomass, estimated by chlorophyll a content, was approximately two to twenty‐fold greater than reported for cryptoendolithic algal bands in a cold desert habitat. The widespread distribution of certain algae in endolithic habitats of the Colorado Plateau and their presence in rocks at quite distant locations suggests that the endolithic habitat may he utilized by algae whenever it provides more favorable conditions than the surrounding surfaces.
THE UPTAKE OF MANNITOL AND SORBITOL BY A SPECIES OF CHLORELLA (CHLOROPHYCEAE)1
Authors: Colman Brian , Brickell Peter C. , Gehl Katharina A. 
Published: March 2008

ABSTRACTChlorella saccharophila (Krüger) Nadson takes up mannitol and sorbitol in the light and the dark. The rate of uptake is concentration dependent. is not affected by pH in the range pH 6.0 to 8.0 and ii not stimulated by light. Uptake is inhibited by the respiration inhibitor sodium azide (10‐2 M) but not by 3‐(3,4‐dichlorophenyl)‐1,1‐di‐methyl urea (10‐6 M), an inhibitor of photosynthesis. Sorbitol. but not mannitol, stimulates the rate of dark respiration but both support the heterotrophic growth of the alga. Both compounds permeate the cells of C. miniata. and two strains of C. pyrenoidosa but do not support the heterotrophic growth of these algae. The cells of C. vulgaris are impermeable to both compounds.
PHYCOBILIPROTEIN COMPOSITION AND CHLOROPLAST STRUCTURE IN THE FRESHWATER RED ALGA COMPSOPOGON COERULEUS (RHODOPHYTA)1
Authors: Gantt Elisabeth , Scott Joe , Lipschultz Claudia 
Published: March 2008

ABSTRACT Serial sections of uncorticated axial cells of Compsopogon coeruleus revealed a single interconnected parietal chloroplast. Phycobilisomes in such chloroplasts were hemidiscoidal in shape with a broad‐face diameter of ca. 25–30 nm. The molar ratio of phycobiliproteins in whole cell extracts was IPE:3PC:1APC, similar to isolated phycobilisomes. Two spectrally distinct C‐phycocyanin forms (A618 nm, F648 nm and A630 nm, F652 nm) were resolved in dissociated phycobilisomes along with B‐phycoerythrin and allophycocyanin.
ULTRASTRUCTURE OF MEIOSIS INDASYA BAILLOUVIANA(RHODOPHYTA). I. PROPHASE I1
Authors: Broadwater Sharon , Scott Joe , Pobiner Bonnie 
Published: March 2008

ABSTRACTThis first of two papers on ultrastructural observations of meiosis in the red algaDasya baillouviana (Gmelin) Montague describes stages of prophase I of meiosis. Although the five stages of prophase were originally derived from light microscopic studies, the same stages were utilized for this study based on the developmental sequence of the synaptonemal complex, which has the same morphology and mode of development as those reported for other red algae. The cytoplasm in early prophase sporocytes was typically less electron dense than either vegetative cells or sporocytes in later stages of meiosis. The reduction in density suggests clearing of ribosomes and other cytoplasmic components prior to conversion from sporophyte to gametophyte control. Leptotene cells often had an amorphous, chromatin‐free area, function unknown, which was not obviously associated with any specific nuclear region. Diplotene cells were characterized by nuclei containing prominent ring‐shaped nucleoli composed of a dark staining ring of material surrounding an electron‐translucent “vacuole.” Packets of electron‐dense, fibrillar material were often noted in the cytoplasm of late prophase cells. These packets are thought to he “nuage,” a term applied to large cytoplasmic aggregations of RNA in germ cells of several other phyla. It is suggested that nuage may represent a new infusion of ribosomal and messenger RNA for post‐meiotic development. The division pales are established by late prophase and a single polar ring is found within each large “exclusion zone” in close association with a pore‐free area of nuclear envelope. Both annulate lamellae and small, numerous vesicles are located in the exclusion zones. The significance of the various aspects of prophase I is discussed with the overall observation that this phase of meiosis in red algae is very similar to the process in higher plant and animal cells.
CELL FORM AND SURFACE PATTERNS INCHROOMONASandCRYPTOMONASCELLS (CRYPTOPHYTA) AS REVEALED BY SCANNING ELECTRON MICROSCOPY1
Authors: Kugrens Paul , Lee Robert E. , Andersen Robert A. 
Published: March 2008

ABSTRACTFifteen freshwater cryptomonad species were freeze‐dried and examined with the scanning electron microscope. Surveys of cell surfaces revealed four general cell types. Chroomonastype cells lack a furrow but possess a shallow vestibular depression where the flagella are inserted. The presence of a gullet could not be detected. Cryptomonasspp. displayed three morphological types, all lacking gullets. The first type ofCryptomonashas a simple, shallow furrow with ridges that apparently can close to form a raphe but an oval opening or stoma remains at the posterior end and an opening from the vestibulum is formed at the anterior end. The secondCryptomonastype consists of a complex furrow with furrow ridges and folds that extend almost two‐thirds of the cell length. A sloma is present in the central region of the closed furrow. The folds apparently can separate thereby exposing the underlying furrow. The third type ofCryptomonaspossesses a simple, non‐closing furrow. At the anterior end there is a vestibular ligule which extends from the dorsalleft side of the cell and covers the region of the vestibulum where the contractile vacuole discharges.
LIPIDS IN BLUE‐GREEN ALGAL MATS (MODERN STROMATOLITES) FROM ANTARCTIC OASIS LAKES1
Authors: Orcutt David M. , Parker Bruce C. , Lusby William R. 
Published: March 2008

ABSTRACT Lipids comprising the stenols, stanols, polar lipid fatty acids, alkanes and alkenes of blue‐green algal‐(diatomaceous)‐microbial mats and cores (modern cold water stromatolites) collected from three Antarctic lakes were identified and compared with those of other algae. The major stenols were: (cholesta‐5, 22‐dien‐3β‐ol, cholest‐5‐en‐3β‐ol, 24‐methylcholesta‐5, 22‐dien‐3β‐ol, 24‐methyl‐cholest‐5‐en‐3β‐ol, 24‐ethylcholesta‐5, 22‐dien‐3β‐ol, and 24‐ethylcholest‐5‐en‐3β‐ol). The presence of C28 Δ3, 22 stenols, as well as other C28 stenols, was suggestive of diatom input. C29 stenols may have originated from blue‐grern algae. However, the high concentrations of stenols present and the lack of Δ7 stenols was atypical for known stenol components of several blue‐green algal species previously reported. The occurrence of these stenols and other lipid markers strongls implicate diatoms as well as blue‐green algae as important biogenetic sources of lipids and has established the potential for studies of lipid diagenesis in these unique cold, freshwater stromatolites.