bluuebunny/crossref_metadata_2025_split huggingface dataset:
CHLOROPHYLL A:B RATIOS IN SOME SIPHONOUS GREEN ALGAE IN RELATION TO SPECIES AND ENVIRONMENT1
Authors: Keast J. F. , Grant B. R. 
Published: August 2007

SUMMARYThe chlorophyll a:b ratios measured in several species of Caulerpa and in Bryopsia plumosa (Hudson) C. Ag. gave values close to 2.00 or below. Values obtained for Ulva lactuca L. taken from the same site gave a higher value of 2.44, and the sea‐grass Heterozostera tasmanica (Martens ex Aschers) den Hartog a value of 2.98.Although there were changes in a:b ratios observed when Caulerpa plants were, stored for up to 10 days in dim light, the values did not suggest that chlorophyll a:b ratios were directly controlled by light intensity. It is conducted that the a:b ratios described in this paper, are a characteristic of the species themselves and are not a result of their growth in extremely shaded situations.
CELLULAR DIFFERENTIATION OF TERMINAL REGIONS OF TRICHOMES OFOSCILLATORIA PRINCEPS(CYANOPHYCEAE)1
Authors: Shukovsky Edward S. , Halfen Lawrence N. 
Published: August 2007

SUMMARYThe terminal regions ofOscillatoria princepsVaucher display cells which differ from intercalary cells of the same trichome. These end cells have an extensively thickened calyptra replacing normal crosswalls. The thylakoids are extensively disrupted in terminal cells and the cytoplasm displays general disorganization characteristic of necrotic cells. The development of terminal regions occurs within a 5 day period following breakage of the trichome and appears characteristic ofO. princeps.The ecological implications of terminal region differentiation are also considered including reaction to variations in current, temperature and light intensities.
DIATOM MINERALIZATION OK SILICIC ACID. I Si(OH)4 TRANSPORT CHARACTERISTICS IN NAVICULA PELLICULOSA
Authors: Sullivan C. W. 
Published: August 2007

SUMMARYSilicic acid transport was studied in the photosynthetic diatom Navicula pelliculosa (Bréb.) Hilse using [68Ge] germanic acid (68Ge(OH)4) as a tracer of silicic acid (Si(OH)4). The initial uptake rate of Si(OH)4 was dependent on cell number, pH, temperature, light and was promoted by certain monovalent cations in the medium. Na+ was more effective than K+, whereas Li+ and NH+4 were ineffective at promoting uptake.Uncouplers and inhibitors of oxidative phosphorylation and of photophosphorylation reduced uptake by 40–99% of control values. Uptake was also especially sensitive to the sulfhydryl blocking agents at 10−5 M and to the ionophorous compound valinomycin (10−7 M) which inhibited uptake by 82%.The Si(OH)4 transport system displayed Michaelis‐Menten‐type saturation kinetics with kinetic parameters of KS= 4.4 p. mol Si(OH)4· 1−1, Vmax= 334 pmol Si(OH)4· 106 cells−1· min−1. Calculations of the acid soluble silicic acid pool size based on 60 s uptake at 20 μM Si(OH)4 suggested that intracellular levels of Si could reach 20 mM and as much as 5 mM could exist as free silicic acid, representing maintenance of a 250‐fold concentration gradient compared with the medium.Efflux from preloaded cells was dependent on temperature and the Si(OH)4 concentration of the external medium. In the presence of 100 μMM “cold” Si(OH)4, approximately 30% of the Si(OH)4 in preloaded cells was exchanged in 20 min.The initial uptake rate of Si(OH)4 in logarithmic phase cells was constant, but the uptake rate increased in a linear fashion for 6 h in stationary phase cells.These results suggest that the first step in silica mineralization by diatoms is the active transmembrane transport of Si(OH)4 by an energy dependent, saturable, membrane‐carrier mechanism which requires the monovalent cations Na+ and K+ and is sensitive to sulfhydryl blocking agents. Silicic acid transport activity also appears to be regulated during different growth stages of the diatom.
ANIN SITUSTUDY OF RECRUITMENT, GROWTH AND SURVIVAL OF SUBTIDAL MARINE ALGAE: TECHNIQUES AND PRELIMINARY RESULTS12
Authors: Neushul M. , Foster M. S. , Coon D. A. , Woessner J. W. , Harger B. W. W. 
Published: August 2007

SUMMARYFouling plates (Plexiglas squares and concrete blocks) were bolted in a horizontal position to racks on the ocean floor at a depth of 12 m. Some of these were periodically taken from the sea, subjected to nondestructive microscopic survey in the laboratory, and then replaced. Others were: a) left undisturbed as controls; b) variously caged to exclude larger predatory animals; or, c) had sediment removed from them at intervals. Populations developing on the periodically surveyed plates were similar to those on undisturbed plates. Populations on undisturbed plates were significantly different from those on partially caged plates. The exclusion of large predators by complete caging resulted in highly significantly different communities from those on partially caged plates. Completely caged Communities were composed mainly of worms, barnacles and bryozoans. Summer‐installed plates supported significantly different populations at the end of the experimental period (12 mo) from winter‐installed plates. Plant growth rates were slow, not exceeding 2 cm/mo, and the mortality rates were often high. A few species had high rates of recruitment and survival each month. Most had high recruitment only in the most favorable growth periods and high loss rates. Physical conditions on the sea floor were measured. The methods developed during this study make it possible to quantitatively describe the growth and reproduction of populations of benthic marine algae in the sea.
INTERACTION OF PLECTONEMA BORYANUM (CYANOPHYCEAE) AND THE LPP‐CYANOPHAGES IN CONTINUOUS CULTURE1
Authors: Cannon Robert E. , Shane Miriam S. , Whitaker Janice M. 
Published: August 2007

SUMMARYContinuous culture techniques are used to study long‐term population interactions between Plectonema boryanum Gomont, a filamentous bluegreen alga, and the LPP‐viruses which infect it. After LPP‐I (virulent cyanophage) infection of sensitive algae, 3 oscillations occur in cell density with concomitant oscillations in virus titer before final stabilization of both algal and viral concentrations. After LPP‐ID and LPP‐2 (temperate viruses) infection, oscillation in cell density occurred with burst of virus particles. Resistant algae always repopulated the chemostat; lysogeny was not established. The interaction between Plectonema that was resistant to virus infection and the 3 LPP‐cyanophages resulted in rapid elimination of the viruses from the chemostat in the effluent. When lysogenic P. boryanum was tested, a law population of virus was present in the chemostat throughout the incubation period indicative of spontancous induction. Clones of lysogenic algae were isolated.
ISOLATION AND CHARACTERIZATION OF GOLGI APPARATUS FROM EGGS OF FUCUS (PHAEOPHYCEAE)1
Authors: Matthews R. A. , Evans L. V. , Callow Maureen E. 
Published: August 2007

SUMMARYA golgi‐rich cell‐free fraction has been obtained from eggs of Fucus serratus L. and characterized by enzyme markers (IDP‐ase and TPP‐ase) and electron microscopy. The results are correlated with cytochemical localization of IDP‐ase and TPP‐ase in situ.
AUTOTROPHIC AND HETEROTROPHIC NUTRITIONAL BUDGET OF SALT MARSH EPIPHYTIC ALGAE1
Authors: Saks Norman M. , Stone Robert J. , Lee John J. 
Published: August 2007

SUMMARYThis paper addresses the nutrition and relative importance of primary production to heterotrophy of select unicellular green algae and diatoms from the same assemblage. Algal growth responses to nutrient additions varied widely. Such responses included: inhibition and enhancement of growth by amino acid additions: nonstimulation or inhibition by most sugars 10 mM concentration; glucose stimulation of 6 and inhibition of 3 species; fructose inhibition of 6‐ and 3‐ fold stimulation of one species; stimulation of most species by a vitamin mixture, some natural products, metabolite mixtures, etc. Photoassimilation of glucose and aculeate in 8 of 12 species occurred. Nine of 12 species took up only a fraction of the total carbon fixed as organic substrate. Enhancement of photosynthesis by glucose and inhibition by acetate was common. The data suggest that attached littoral and shoal marine algal assemblages may play mixed trophic roles lower levels of the detrital food web.
THE ROLE OF GLUTAMINE SYNTHETASE IN THE INCORPORATION OF AMMONIUM INSKELETONEMA COSTATUM(BACILLARIOPHYCEAE)1
Authors: Falkowski Paul G. , Rivkin Richard B. 
Published: August 2007

SUMMARYTheKmfor ammonia for glutamine synthetase and glutamate dehydrogenase was measured in enzyme extracts fromSkeletonema costatum(Grev.) Cleve. At similar physiological pH and temperature the half‐saturation constant for glutamine synthetase was 29 μM, whereas for GDH it was 28mM. On the basis of relative enzymic activity, as well as substrate affinity, it is suggested that glutamine synthetase is the enzyme primarily responsible for the incorporation of ammonium into the amino acid pool, when extracellular nitrogen is at ecological concentrations.
FURTHER EVIDENCE FOR A MEMBRANE‐BOUND ENDOSYMBIONT WITHIN THE DINOFLAGELLATEPERIDINIUM FOLIACEUM1
Authors: Jeffrey S. W. , Vesk Maret 
Published: August 2007

SUMMARYThe fine structure of the binucleate, fucoxanthin‐containing dinoflagellatePeridinium foliaceum(Stein) Biechler was re‐examined for evidence of an endosymbiout. The eucaryotic nucleus, chloroplasts and associated ribosome‐dense cytoplasm were separated by a single invaginating membrane from the rest of the dinoflagellate cell. The triple membrane‐enclosed eyespot, mesocaryotic nucleus, trichocysts and accumulation bodies resided in the dinoflagellate cytoplasm. These observations suggest thatP. foliaceumcontains a membrane‐bound endosymbiont, similar to that already described for the closely related species.P. balticum(Levander) Lemmermann.
ALGAL SYMBIONT OF A SOFT CORAL1
Authors: Singh A. P. , Mercer E. H. 
Published: August 2007

SUMMARYThe algal symbiont of the soft coral Sarcothelia edmondsoni (Verrill), is identified as the dinoflagellate Gymnodinium microadriaticum (Freudenthal) Taylor on the basis of its cytology apparent in electron micrographs. The character of the nucleus, peripheral lobed chloroplast with a vase‐shaped pyrenoid body and other inclusions form the basis for identification.
CALCIFICATION IN THE GREEN ALGAHALIMEDA.I. AN ULTRASTRUCTURE STUDY OF THALLUS DEVELOPMENT1
Authors: Borowitzka Michael A. , Larkum Anthony W. D. 
Published: August 2007

ABSTRACTThe ultrastructure of 4 species of the calcareous, siphonaceous algaHalimeda (H. cylindraceaDecaisne,H. discoideaDecaisne,H. macrolobaDecaisne andH. tuna(Ellis & Solander) Lamour) has been studied, and the observed changes during growth and development are related to changes in the degree of calcification. A distinct gradient in the types and quantities of cell organelles exists in a growing apical filament. As these filaments grow, branch, and eventually develop into a mature segment, changes in the organization of organelles such as mitochondria and chloroplasts are observed. Calcification begins when the chloroplasts reach structural maturity and when the peripheral utricles adhere (fuse). This adhesion of the peripheral utricles isolates the intercellular space (ICS) in which calcification occurs from the external seawater. Calcification begins in the outermost (pilose) cell wall layer of the walls facing into the ICS. The cell walls at the thallus exterior undergo extensive changes after utricular fusion; the pilose layer is lost, the cuticles of adjacent utricles fuse forming a ridge at their junction, and multiple cuticles are formed.The aragonite (CaCO3) crystals which are initially precipitated within the pilose wall layer, rapidly increase in size and number, eventually filling much of the ICS. Only the initial nucleation of aragonite is associated with the pilose wall layer, the later precipitation of aragonite is totally independent of the pilose layer. In older segments secondary deposition of CaCO3also occurs around existing aragonite needles.
DEVELOPMENT OF MUCILAGINOUS SURFACES IN EUGLENOIDS. I. STALK MORPHOLOGY OF COLACIUM MUCRONATUM1
Authors: Rosowski James R. , Willey Ruth L. 
Published: August 2007

ABSTRACTThe envelope and stalk of Colacium mucronatum Bourr. & Chad, were examined in living cells with light microscopy and in fixed preparations with scanning electron microscopy using critically point dried (CPD) and freeze dried (FD) preparations. The envelope of palmelloid cells is formed over the entire cell surface by many individual strands attached at right angles to areas of articulation of the pellicular strips. Strands were observed to anastomose on the posterior tip of otherwise naked cells. Stalks of living cells in India ink preparations had an optically dark inner core with a lighter outer sheath. In FD stalks a definite inner core was not evident, whereas CPD stalks had an outer surface composed of thick strands which may be the collapsed and aggregated strands of the FD stalks. In both there was also an amorphous matrix. The stalk forms from the aggregation of many strands from the anterior cell tip back to a point encompassing the cell surface anterior to a cross section of the tip 9 μm diam. The outer surface of the stalk comes from the pellicular surface joining that area and the core from the cell tip in the area of the canal opening. Any possible participation of the inner canal surface in stalk formation could not be determined because of the great density of the mucilage at the cell‐tip/stalk junction.
PHOTOSYNTHESIS IN THE SNOW: THE ALGACHLAMYDOMONAS NIVALIS(CHLOROPHYCEAE)1
Authors: Mosser J. L. , Mosser A. G. , Brock T. D. 
Published: August 2007

ABSTRACTRed blooms of snow algae consisting almost exclusively of large spherical red cells ofChlamydomonas nivalis(Bauer) Wille are widespread during the summer in the Beartooth Mountains in Montana and Wyoming. Field studies designed to examine the effects of temperature, light, and water potential on algal activity were performed with natural populations using photosynthetic14C‐HCO3‐ or14CO2incorporation as a measure of activity. The algae photo‐synthesized optimally at 5.4 × 104lx, but were not inhibited by increased light intensity up to 8.6 × 104lx, the maximum observed in the field. Photosynthesis was sensitive to a reduction in water potential, and since low water potentials develop in snow at temperatures below 0 C, it is unlikely that significant algal activity occurs at the sub‐0 temperatures which occur throughout winter. Photosynthesis was much lower following melting of the snow, but this was probably due to decreased diffusion of CO2. The optimal temperatures varied considerably among the different algal populations. Most samples photo‐synthesized optimally at 10 or 20 C but retained substantial activity at temperatures as low as 0 or ‐3 C. Exceptional samples photosynthesized optimally at 0 or ‐3 C. It is proposed that the varied temperature responses reflect the presence of different temperature strains. Taken together, the data suggest that development of the snow algae can occur only during the summer months.
CYTOCHROME c548 IN NOSTOC SP. (CYANOPHYCEAE): AN ELECTRON ACCEPTOR FROM REDUCED NADP IN THE DARK1
Authors: Pulich Warren 
Published: August 2007

ABSTRACTA c‐type, carbon monoxide‐binding cytochrome was isolated and studied from an endophytic Nostoc sp. Enzymatic transfer of electrons from NADPH to this cytochrome was demonstrated in cell‐free preparations under dark, anaerobic conditions, probably mediated by NADPH‐cytochrome reductase or ferredoxin‐NADP reductase present in the extracts. This cytochrome, with an α‐peak at 548 nm, had physicochemical properties similar to the low potential c‐type cytochrome, cytochrome c549, previously described by other workers from Anacystis nidulans. The participation of such c‐cytochromes in dark electron transport, possibly respiratory, of bluegreen algae is strongly indicated.
AN INVESTIGATION OF THE VERTICAL DISTRIBUTION OF SELECTED BENTHIC MARINE ALGAE WITH A TIDE–SIMULATING APPARATUS1
Authors: Edwards Peter 
Published: August 2007

ABSTRACTThe growth yields of 8 species of red and 4 species of green algae, collected from various vertical levels on the western Atlantic (New Jersey) shore, were investigated in a range of emersion‐submersion regimes in the laboratory. The sinusoidal tide‐simulating apparatus consisted of a plexiglass frame connected by a nylon thread to a rotating wheel, powered by an electric motor geared to make one revolution every 12 h. Inocula of settled spores on glass cover‐glasses were placed at 6 levels on the frame and alternately raised out of, and lowered into, a seawater tank every 6 h with consequent subjection to 0, 18, 37, 58, 79, and 100% submergence regimes per tidal cycle. There was little correlation between the vertical position of a species on the shore in nature and its ability to grow as the percentage submergence per tidal cycle increased. All species tested grew best when continuously submerged, even those that are usually restricted to elevated positions on the shore in nature. The majority grew well in all regimes in which there was some submergence per tidal cycle, except for one sublittoral species (Callithamnion byssoides) whose growth decreased sharply as the percentage exposure to the air was increased.
DIATOM MINERALIZATION OF SILICIC ACID. II. REGULATION OF Si (OH)4 TRANSPORT RATES DURING THE CELL CYCLE OF NAVICULA PELLICULOSA1
Authors: Sullivan C. W. 
Published: August 2007

ABSTRACTSynchronized populations of Navicula pelliculosa (Bréb.) Hilse show a 10‐fold increase in Si(OH)4 transport rate during traverse through the cell division cycle. The transport activity pattern is similar to a “peak enzyme.” Kinetic analysis showed there was a significant change in Ks values, indicating increased “affinity” for Si(OH)4 as cells neared maximal uptake rates. However, the dramatic changes in transport rate at various cell cycle stages were also reflected by alterations in the Vmax, values of the transport process, suggesting a change in the number of functional transport “sites” in the plasma membrane. Cells in the wall forming stage, arrested from further development by Si(OH)4 deprivation, maintained high transport rates for as long as 7 h. The rates decreased rapidly if protein synthesis were blocked or if Si(OH)4 was added, the latter allowing the cells to traverse the rest of the cycle. The half‐life of the transport activity ranged from 1.0 to 2.2 h when protein synthesis was inhibited at various cell cycle stages and during the natural decline of activity late in the cycle. The transport system appears to be metabolically unstable as is typical for a “peak protein.” The rise in transport rate through the cell cycle did not depend on the presence of Si(OH)4 in the medium; therefore, the transport system does not appear to be induced by its substrate. The rise in transport is also observed in L:D synchronized cells developing in the presence of Si(OH)4; neither does the transport system appear to be derepressed. The transport rate was strongly cell cycle‐stage dependent; the data appeared to fit the “dependent pathway” model proposed by Hart‐well to explain oscillations in enzyme synthesis during the cell cycle.
FACTORS INFLUENCING THE TOXICITY AND ANIMAL SUSCEPTIBILITY OF ANABAENA FLOS‐AQUAE (CYANOPHYTA) BLOOMS1
Authors: Carmichael Wayne W. , Gorham Paul R. 
Published: August 2007

ABSTRACTBiological factors have been found which can cause variable toxicity of colony and clonal isolates of Anabaena flos‐aquae (Lyngb.) de Bréb. when cultured in the laboratory. These factors help to explain some of the variable toxicity of and animal susceptibility to A. flos‐aquae blooms in nature. Two bacteria in the Enterobacteriaceae isolated from a toxic waterbloom, depressed toxin production in selected bacteria‐free toxic clones of A. flos‐aquae. These toxin‐depressing bacteria decreased culture toxicity 3‐fold from 80 to 240 mg/kg (intra‐peritoneal in male mice). Many colony isolates from a toxic bloom had minimum lethal dosages (LDmin) greater than 240 mg/kg. This was because they were composed of mixtures of toxic and nontoxic filaments. The oral LDmin of the toxin from A. flos‐aquae clonal isolate NRC‐44‐1 varied significantly for 6 different animal species. Using these oral LDmin it is estimated that a surface‐concentrated bloom of toxic A. flos‐aquae, having a biomass density of 20 mg/ml dry weight, would cause death of ducks or calves when 20 ml/kg was consumed whereas a monogastric animal such as a rat would require 80 ml/kg.
CELL DIVISION AND COLONY FORMATION IN THE GREEN ALGACOELASTRUM(CHLOROCOCCALES)1
Authors: Marchant Harvey J. 
Published: August 2007

ABSTRACTMultinucleate cells ofCoelastrumundergo precisely directed cytokinesis, guided by phycoplast microtubules, to form a number of uninucleate daughter cells which subsequently adhere to form characteristically patterned aggregates. As there is no movement of the daughter cells relative to one another before their adhesion, the disposition of cells in daughter colonies reflects the pattern of cytokinesis of parent cells. Centrioles lie at the poles of the mitotic nuclei which are partially enclosed by a perinuclear envelope of endoplasmic reticulum. The centrioles disappear at the time of cytokinesis of the parental cell and apparently reformde novoonce the daughter cells have acquired a cell wall following their adhesion. The trilaminar layer of cell wall, often termed the pectic layer, does not stain with ruthenium red and resists acetolysis suggesting that it contains sporopollenin rather than pectin.
A STUDY OF IN VITRO ELECTRON TRANSPORT ACTIVITY IN MARINE PHYTOPLANKTON AS A FUNCTION OF TEMPERATURE1
Authors: Ahmed S. I. , Kenner R. A. 
Published: August 2007

ABSTRACTThe in vitro temperature inactivation of the electron transport system (ETS) activity was measured for 11 phytoplankton species. The average inactivation temperature is between 18–23 C, but exceptions with inactivation temperatures as high as 43 C were noted for a tide pool phytoplankton, Dunaliella tertiolecta Butcher. Despite differences in temperatures at which the ETS activity begins to decrease, experimental values for the energies of activation (E) of electron transport are very similar and average ca. 12 kcal/mol. The results show the necessity of applying temperature corrections to in vitro ETS activity measurements when oceanic in situ oxygen consumption is computed from ETS activity measurements. The progress of thermal inactivation of the ETS activity in phytoplankton species studied yields biphasic curves. The biphasic nature of the curves is expressed when using both relatively high and low temperature of inactivation and in more or less heat sensitive species. These curves are described in terms of microsomal and mitochondrial substrate dependence. Based on the obtained temperature response of the ETS activity, the adaption of phytoplankton species to growth temperature is discussed.
PROTEIN AND AMINO ACID COMPOSITION OF THE OBLIGATE HALOPHILE APHANOTHECE HALOPHYTICA (CYANOPHYTA)1
Authors: Tindall Donald R. , Yopp John H. , Schmid Walter E. , Miller Donald M. 
Published: August 2007

ABSTRACTTotal protein was determined for cells of Aphanothece halophytica Fremy harvested during early log, mid‐log and linear growth phases in media containing 1, 2, and 3 M NaCl. Cells grown in medium containing 1 M NaCl showed a progressive increase in protein content up to a maximum of 76% of dry weight (linear phase). Total protein also increased in cells grown in 2 M NaCl. medium (56.5–72.0%). Cells grown in 3 M NaCl medium showed a progressive decrease in total protein (59.9–43%). Although amounts of protein varied, the percentages of the respective amino acids of hydrolyzed bulk protein were consistent to within 1% for linear phase cells grown in 1, 2, and 3 M NaCl cultures. Percentages of acidic amino acids were 2.3–2.6 times greater than those of the basic amino acids. The amino acid composition of phycocyanin was similar to that of bulk protein. Free amino acids varied with both age of the culture and the concentration of NaCl. The high quantity and quality of the protein observed suggest that A. halophytica might be a useful food organism.