bluuebunny/crossref_metadata_2025_split huggingface dataset:
INFLUENCE OF SALINITY ON THE FORM OF ASTEROCYTIS IN PURE CULTURE1
Authors: Lewin Ralph A. , Robertson Jack A. 
Published: August 2007

SUMMARYThe growth form of an isolate of Asterocytis ornata in pure culture changed from filamentous in a full‐strength seawater medium to a unicellular or bicellular form closely resembling the genus Chroothece in a medium of quarter‐strength seawater. The alga did not grow in media of lower salinities, or in media in which seawater was replaced by KCl, NaCl, or CaCl2. The formation of filaments from single cells could not be attributed to osmolarity. The controlling factors seemed to be the concentrations of cations, notably Na+ and Mg++. However, the filaments produced experimentally in a defined medium, were never as extensively developed as those occurring in seawater, an indication that further studies should be done. The occurrence of the Asterocytis form, in freshwater habitats remains to be explained. There may be distinct physiological races, if not true species, within the genus.
ECOLOGY OF THE EPIPELIC ALGAL COMMUNITIES IN MARION LAKE, BRITISH COLUMBIA1,2
Authors: Gruendling Gerhard K. 
Published: August 2007

SUMMARYStudies of the seasonal and spatial distribution of the epipelic algal standing crop and primary productivity were conducted in Marion Lake, British Columbia. Possible biological, chemical, and physical factors controlling the epipelic algal community dynamics were also investigated. The epipelic algal flora of the lake was very diverse, however, it can be generally considered as acidophilic associations of algae. The vertical distribution of the epipelic algae is partially influenced by the amount of light reaching the sediment, but also strongly influenced by the grazing of animals and erosion by wave action. Temperature, light, and grazing by animals all appear to influence the seasonal fluctuations in the algal standing crop. Concentrations of nutrients immediately above the sediment surface appear to be less important as controlling factors. The most important variables influenceing the primary productivity of the epipelic community are temperature, total algal standing crop, and light. Nutrients, again, appear to be less important as controlling factors. The study supports the idea that epipelic algal growth is high in shallow, low nutrient lakes and that the epipelic algal productivity is extremely important to the total energy budget of the lake.
ENERGY EXPENDITURE FOR GLIDING MOTILITY IN A BLUE‐GREEN ALGA1
Authors: Halfen Lawrence N. , Caslenholz Richard W. 
Published: August 2007

SUMMARYThe energy required to overcome viscous drag in a gliding trichome of a blue‐green alga advancing and rotating through a medium of known viscosity (67 poise at 25 C) has been calculated to be about 0.05% of the energy available from oxidative phosphorylation (based on respiration measurements), whereas 0.2–5% are possible figures for the amount actually expended. These values represent a low energy demand for a function of probable high survival value, but are comparable to estimates for motility in flagellated cells.
AN EXOCELLULAR POLYSACCHARIDE FROM THE DIATOM GOMPHONEMA OLIVACEUM1,2
Authors: Huntsman Susan A. , Sloneker J. H. 
Published: August 2007

SUMMARYAn acidic polysaccharide produced by Gomphonema olivaceum was extracted with hot water after conversion to its potassium form. Recovered in 2–3% yield, the β‐linked polysaccharide was composed primarily of d‐galactose, d‐xylose, and an alkalistable sulfate ester in the ratio of 1:1:1.2. Several other minor components including a uronic acid were observed but not further identified. Periodate oxidation was complete in 40 hr at 4 C with the consumption of 0.88 mole of oxidant and production of 0.26 mole of acid per sugar residue. Half of the d‐galactose in the polysaccharide was not oxidized by periodate: the remainder was cleaved between C2 and C3. Of the d‐oxylose residues, 35% were not oxidized; 15% were cleaved beetween C2 and C3; and 50%, presumbably a nonreducing side‐chain moiety, afforded formic acid. From these data two possible structures have been proposed.
NEW ALGAL SPECIES RECORD FOR COLORADO1
Authors: Todd Darryl J. 
Published: August 2007

SUMMARYColonies of the alga Nostoc parmeloides Kützing 1843, containing midge larvae, were collected from Bellows Creek in the southwestern mountains of Colorado near Creede, Mineral County, on February 27, 1970. G. W. Prescott verified the algal identification and confirmed it as a new species record for Colorado. The Nostoc‐midge combination has been definitely identified in 8 other Colorado mountain streams. The streams are located in various sections of Colorado above 2333 m; distribution may be statewide.
CYTOKINESIS AND PLASMODESMATA IN ULOTHRIX1
Authors: Floyd Gary L. , Stewart Kenneth D. , Mattox Karl R. 
Published: August 2007

SUMMARYCytokinesis essentially similar to that of vascular plants occurs in Ulothrix, an unbranched filamentous green alga. Plasmodesmata, similar to those of vascular plants, but different from those of many other algae, are also present. Cell plate formation and plasmodesmata also occur in Stigeoclonium, a branched green alga.
BIPHASIC TIME COURSE OF SOLUBILIZATION OF NITROGENASE DURING CAVITATION OF AEROBICALLY GROWN ANABAENA CYLINDRICA1
Authors: Wolk C. Peter , Wojciuch Elizabeth 
Published: August 2007

SUMMARYThe nitrogenase activity of extracts from aerobically grown. Anabaena cylindrica is proportional to the cube of the concentration of extract over a wide range of activities. This relationship is changed to one of direct proportionality, approximately, when reaction mixtures are supplemented with a constant amount of extract from algae starved for molybdenum in the presence of tungstate. The time course of solubilization of nitrogenase during cavitation is reevaluated in the light of these results. The finding that solubilization occurs at first rapidly and subsequently much more slowly is discussed with reference to the hypothesis that nitrogenase is localized in heterocysts.
GLUCOSE UPTAKE BY CYCLOTELLA CRYPTICA: DARK INDUCTION AND LIGHT INACTIVATION OF TRANSPORT SYSTEM1,2
Authors: Hellebust Johan A. 
Published: August 2007

SUMMARYGlucose transport capacity of C. cryptica increases in an exponential manner over 24 hr after transfer of the cells from light to complete darkness with little simultaneous increase in cell number. The transport system is rapidly inactivated when cells are transferred back to continuous light. Most of the inactivation takes place while there is still little changes in cell number. When grown on a continuous light regime, the capacity for glucose transport per cell depends on the light intensity. At intensities sufficient to saturate photosynthesis the glucose transport system is only about 5% that of dark‐grown cells, while cells grown at intensities close to the light compensation point have about 30% of the capacity of dark‐grown cells. The action spectrum for inactivation of glucose transport is identical to that for photosynthesis.Cells, whether grown under continuous light, in the dark in the presence of glucose, or kept in the dark without glucose, contain high levels of glucokinase and phosphofructokinase. The glucose transport system is highly specific for glucose; only galactose inhibits the uptake of glucose by about 50% when present at 10 times the concentration of glucose. The glucokinase is even more specific for glucose and is not inhibited by galactose. The phosphofructokinase is inhibited by high concentrations of ATP in cells grown under all conditions. cycloheximide inhibits the induction of glucose transport in the dark, but not the inactivation of the system in the light.
A LIGHT AND ELECTRON MICROSCOPIC STUDY OF RHIZOID DEVELOPMENT IN POLYSIPHONIA LANOSA (L.) TANDY1,2
Authors: Rawlence David J. , Taylor A. R. A. 
Published: August 2007

SUMMARYThe ontogeny of P. lanosa rhizoids was investigated by light and electron microscopy. A series of distinct, changes was recognized. Prior to penetration of the host, Ascophyllum nodosum, starch reserves were depleted and a large number of dictyosome vesicles accumulated in the cell. These appeared to have been discharged immediately prior to or during host, penetration with a concomitant increase in rhizoid wall thickness. Following initial penetration, the tip became highly convolute and dominated by ER, ribosomes, and mitochondria. Senescence was marked by almost complete, vacuolation of the cytoplasm, degeneration of most organelles, and the loss of color. These ultrastructural changes are correlated wth the habit of P. lanosa.
DISTRIBUTION OF PHYTOPLANKTON IN A POLLUTED SALINE LAKE, ONONDAGA LAKE, NEW YORK1,2,3
Authors: Sze Philip , Kingsbury John M. 
Published: August 2007

SUMMARYOnondaga Lake, possibly the most polluted lake in New York State, supports an algal flora characteristic of a eutrophic lake with an admixture of saline species. Floral diversity is noteworthy under the circumstances. Seasons in the lake may be identified by the succession of flora. High salinity of lake water results in layering at the outfall (as in an estuary, in reverse) such that river water may enter the lake at the outlet despite continuous net outflow. Certain species of algae appeared first at the outflow station and then spread through the lake. Phosphorus and nitrogen are never limiting, although seasonal diminution in the latter may influence the composition of the flora. Silica diminution was related to blooms of diatoms and may then be limiting for further growth of diatom populations. No obvious controlling relationship exists between herbivores and phytoplankton populations. The euphotic layer is typically much shallower than the thermocline. Therefore turbulence and mixing may play an important role in controlling certain populations. A brief midsummer clearing in 1969, characteristic for the lake, resulted in serious oxygen depletion and cannot be accounted for with the available data. Among metals, chromium and copper are high in the lake as the result of industrial discharges. The former may be inhibiting, the latter probably is inhibiting to algal growth. Consequently, measures underway to “clean up” the lake may result in increased blooms. Biomass calculations have been made for the major phytoplankters, and a list of 82 species is presented.
OBSERVATIONS ON THE ULTRASTRUCTURE OF THE MALI GAMETES OF BIDDULPHIA LEVIS EHR.1
Authors: Heath I. Brent , Darley W. Marshall 
Published: August 2007

SUMMARYThe marine centric diatom Biddulphia levis produced uniflagellate fusiform male gametes completely within the parent cell frustule. These gametes lacked both a central pair of microtubules in the flagellar axoneme and chloroplasts but did contain a cone of microtubules which passed posteriorly from the base of the kinetosome along the nuclear envelope. The gametes were released through a specialized pore in the girdle band leaving behind a cytoplasmic mass which contained chloroplasts and other cytoplasmic components. Tubules which resembled the flimmer hairs on the gamete flagellum occurred in cisternae of the cytoplasmic reticulum in the residual cytoplasm and in the nuclear envelope of the gametes. Gametogenesis in B. levis is compared with similar processes in other centric diatoms.
ACID PHOSPHATASE ACTIVITY AND ULTRASTRUCTURE OF AGED CELLS OF EUGLENA GRANULATA1,2
Authors: Palisano John R. , Walne Patricia L. 
Published: August 2007

SUMMARYUltrastructure and acid phosphatase activity of aged calls of Euglena granulata are reported. Cells are spherical, quiescent, and nonflagellated. The most conspicuous attribute of aged cells is the accumulation of cyloplasmic vacuoles and lysosome‐like structures containing heavily stained, pigmented bodies and membrane fragments. In chloroplasts, portions of whorled lamellae arc abscised and subsequently incorporated into lysosome‐like structures; osmiophilic granules increase in number. Membranes surrounding eyespot granules disappear and the granules themselves become diffuse; the usual association with microtubules is not seen in aged cells. Acid phosphatase precipitation accumulates largely at the maturing face of dictyosomes and associated vesicles; there is also activity in multivesicular and lysosome‐like vacuoles.
THE FINE STRUCTURE OF MITOSIS AND CELL DIVISION IN THE CHRYSOPHYCEAN ALGA OCHROMONAS DANICA1
Authors: Slankis T. , Gibbs Sarah P. 
Published: August 2007

SUMMARYAt the ultrastructural level, cell division in Ochromonas danica exhibits several unusual features. During interphase, the basal bodies of the 2 flagella replicate and the chloroplast divides by constriction between its 2 lobes. The rhizoplast, which is a fibrous striated root attached to the basal body of the long flagellum, extends under the Golgi body to the surface of the nucleus in interphase cells. During proprophase, the Golgi body replicates, apparently by division, and a daughter rhizoplast, appears. During prophase, the 2 pairs of flagellar basal bodies, each with their accompanying rhizoplast and Golgi body, begin to separate. Three or 4 flagella are already present at this stage. At the same time, there is a proliferation of microtubules outside the nuclear envelope. Gaps then appear in the nuclear envelope, admitting the microtubules into the nucleus, where they form a spindle. A unique feature of mitosis in O. danica is that the 2 rhizoplasts form the poles of the spindle, spindle microtubules inserting directly onto the rhizoplasts. Some of the spindle microtubules extend from pole to pole; others appear to attach to the chromosomes. Kinetochores, however, are not present. The nuclear envelope breaks down, except, in the regions adjacent, to the chloroplasts; chloroplast ER remains intact throughout mitosis. At late anaphase the chromosomes come to lie against part of the chloroplast ER. This segment of the chloroplast ER appears to be incorporated as part of the reforming nuclear envelope, thus reestablishing the characteristic nuclear envelope—chloroplast ER association of the interphase cell.
GROWTH AND EXCRETION IN PLANKTONIC ALGAE AND BACTERIA1
Authors: Nalewajko C. , Lean D. R. S. 
Published: August 2007

SUMMARYIn short‐term experiments using cultures ofChlorella pyrenoidosa, Anabaena flos‐aquae, Asterionella formosa, andNavicula pelliculosa, both the proportion of photosynthetic products released from cells and the composition of these products altered, with age. In the first 3 species, percentage extracellular release values increased with increasing growth rates but the reverse trend was shown byNavicula.Fractionation of filtrates using Sephadex indicated that, in general, larger molecular weight compounds became predominant as cultures aged. Also a time‐dependent shift in a similar direction occurred in cultures of all ages.In several lakes a predominance of large molecular weight compounds was apparent in filtrates even from short‐term experiments. Filtrates of mixed cultures of planktonic bacteria growing on14C glycolate were found to contain, large molecular weight organic compounds.It was demonstrated that in nonaxenic cultures of algae and in lake water, bacteria utilize low molecular weight extracellular metabolites of algal origin and larger molecular weight compounds are formed.
ULTRASTRUCTURE OF TETRASPOROGENESIS IN THE PARASITIC RED ALGA LEVRINGIELLA GARDNERI (SETCHELL) KYLIN12
Authors: Kugrens Paul , West John A. 
Published: August 2007

SUMMARYUltrastructural studies on tetraspore formation in Levringiella gardneri revealed that 3 stages may be recognized during their formation. The youngest stage consists of a uninucleate tetraspore mother cell with synaptonemal complexes present during early prophase of meiosis I. Mitochondria are aggregated around the nucleus, dictyosome activity is low, and chloroplasts occur in the peripheral cytoplasm. A 4‐nucleate tetraspore mother cell is formed prior to tetrahedral cell cleavage, and an increase in the number of chloroplasts and mitochondria occurs. Small straight‐profiled dictyosomes secrete vesicles into larger fibrous vesicles or contribute material to the developing tetraspore wall. During the second stage of tetraspore formation, striated vesicles form within endoplasmic reticulum, semicircular profiled dictyosomes secrete vesicles for fibrous vesicles or wall material, and starch formation increases. The final stage is characterized by the disappearance of striated vesicles, presence of straight, large dictyosomes which secrete cored vesicles, and an abundance of starch grains. Cleavage is usually complete at this stage and the tetraspore wall consists of a narrow outer layer of fibrillar material and an inner, electron transparent layer. These spores are surrounded by a tetrasporangial wall which was the original wall surrounding the tetraspore mother cell.
THE UPTAKE OF GLUCOSE BY CHLAMYDOMONAS SP.12
Authors: Bennett M. Elwanda , Hobbie John E. 
Published: August 2007

SUMMARYThe glucose uptake of a species of Chlamydomonas was studied at various concentrations of d‐glucose plus glucose‐1‐14C (0.003–10.0 mg/liter) and at various light levels (0–220 ft‐c). The alga grows at 4 C either in the light or in the dark with added glucose, cellobiose, maltose, or fructose. Uptake of glucose could be described by the Michaelis‐Menten equation, and both the maximum velocity of uptake and the half‐saturation constant increased when the cells were exposed to glucose in the dark. However, the high value of the half‐saturation constant (5 mg glucose/liter) compared with the low levels of glucose in nature (5–10 μg/liter) makes it unlikely that a transport system is effective under natural conditions. Even if a total of 10.0 mg/liter of glucose plus other organic compounds were available as substrate, the rate of photosynthesis would still be more than 10 times higher (at 220 ft‐c) than the rate of organic substrate uptake.Light had no effect on the total uptake of glucose but did reduce the percentage of 14CO2 evolved from 61% of the total 14CO taken up in the dark to 0% at 220 ft‐c. This decrease could be due to either preferential use of the 14CO2 in photosynthesis or of the photosynthate in respiration.
KINETICS OF AMINO ACID INFLUX INTO NITELLA FLEXILIS1
Authors: Wallen D. G. 
Published: August 2007

SUMMARYThe uptake of amino acids by Nitella flexilis has been investigated. Influx of glycine, alanine, and valine appears to be a diffusive process. Influx ranged from 0.14 to 0.06 and 0.04 pmoles/(cm)(sec), respectively. Aspartic acid uptake is an active transport mechanism. The Vmax is 2.8 pmoles/(cm)(sec); the transport constant (Michaelis constant) Km, 7.8 × 10−3 M. The uptake of arginine is apparently due to 2 transport systems, one with a Vmax and Km of 3.1 pmoles/(cm)(sec) and 3.2 × 10−3M, respectively. The second system has a Vmax of 1.4 pmoles/(cm)(sec) and a Km of 2.1 × 10−4 M. The possibility that the second system is diffusive has been considered.
CONTINUOUS CULTURE OF MARINE DIATOMS UNDER SILICATE LIMITATION. I. SYNCHRONIZED LIFE CYCLE OF SKELETONEMA COSTATUM12
Authors: Davis Curtiss O. , Harrison Paul J. , Dugdale Richard C. 
Published: August 2007

SUMMARY Skeletonema costatum was grown in silicate‐limited continuous culture, Culture conditions resulted in synchronization of sexual reproduction. A detailed description of the life cycle is presented. During the life cycle growth rules varied from 0 to 0.12 hr−1. Sexual reproduction in diatoms has often been observed in batch cultures and some stages have been reported in nature. However, this is apparently the first report of its occurrence in continuous culture. Other experiments that demonstrate the importance of sexual reproduction in continuous culture work tare discussed.
SEXUAL INDUCTION IN EUDORINA: EFFECTS OF LIGHT, NUTRIENTS, AND CONDITIONED MEDIUM1
Authors: Szostak J. W. , Sparkuhl J. , Goldstein M. E. 
Published: August 2007

SUMMARYThe generation time of Eudorina and the time required for a male clone to produce sperm packets decreased with increased light intensity. Nutrient levels were not limiting for either process at the concentrations used in Volvox medium. Effects of various transfer schedules are discussed. A dialyzable substance which induces sperm packet formation was detected in medium in which Eudorina was grown. Methods for the preparation and assay of this substance are described.
EFFECTS OF CARBON, NITROGEN, AND ALLOPURINOL ON THE ABUNDANCE OF PARTICIPATE INCLUSIONS IN A MARINE DINOFLAGELLATE12
Authors: Gold Kenneth , Pokorny Kathryn Stein 
Published: August 2007

SUMMARYNutritional factors have been identified that affect the abundance of particulate inclusions in the heterotrophic dinoflagellateCrypthecodinium cohnii.The amount of ammonium sulfate. glucose, and glutamic acid in the medium markedly affected the number of particle‐containing cysts. Particle production was directly proportional to the concentration of ammonium sulfate and glutamic acid, and inversely proportional to the amount of glucose in the medium. Allopurinol reduced particle production Strikingly. The chemical composition of the particulate inclusions, and their possible ecological significance, are discussed.
THE DETERMINATION OF THE FAR‐RED EFFECT IN MARINE PHYTOPLANKTON1,2
Authors: Lipps Mary Jo 
Published: August 2007

SUMMARYA far‐red effect exists in 4 marine phytoplankton species: the diatom Ditylum brightwelli, the coccolithophorid Coccolithus huxleyi, the green flagellate Dunaliella tertiolecta, and the dinoflagellate Pyrocystis lunula. The effect is reversible and is manifested through a change in cell division rate. Cultures of algae which received 30‐min far‐red (FR) light (750 nm) prior to the dark period were compared to controls which received, no FR. Reversal of the FR effect was studied by exposing experimental cultures to 30 min FR followed by 5‐min red (R) light (650 nm) prior to the dark period. Controls received only FR. Cultures were exposed to light at 6 different enumerated wavelengths between 460 and 750 nm. A decrease in division rate runs evident only with light at 750 nm. These results give evidence for the presence of the phytochrome system in these phytoplankton species.
THE EFFECT OF TEMPERATURE ON PARASITISM OF PANDORINA SP. BY DANGEARDIA MAMMILLATA B. SCHRÖDER IN AN ARIZONA MOUNTAIN LAKE1,2
Authors: Blinn Dean W. , Button Kenneth S. 
Published: August 2007

SUMMARYA chytridiaccous fungus, Dangeardia mammillata, was found to be selectively parasitizing the volvocalean Pandorina sp. in a shallow eutrophic mountain lake in northern Arizona. Population estimates of infected algal colonies reached. 68% during epidemic periods (Feb.‐Mar.). Selected physicochemical parameters were measured during the infection period, with temperature found to be the most important factor in regulating chytrid parasitism. Infection only occurred at temperatures below 17 C in the field, and infection only at low temperatures was confirmed by laboratory investigations. Other parameters showed no apparent relationship with the chytrid‐algal association. The roles of photosynthetic exudates are also discussed in regulation of chytrid parasitism.