bluuebunny/crossref_metadata_2025_split huggingface dataset:
CHAIN‐FORMING DIATOMS: THREE SPECIES OF CHAETOCERACEAE1,2
Authors: Fryxell Greta A. 
Published: April 2006

ABSTRACT Bacteriastrum furcatum Shadbolt, Chaetoceros bacteriastroides Karsten and C. pseudocurvisetum Mangin are each connected in chains by fusion of silica between setae. The first two have specialized heterovalvate end cells indicating physiological control of the length of chains, but chains of C. pseudocurvisetum have usually been seen broken. There are specialized deeply lobed connecting bands in B. furcatum and C. pseudocurvisetum, allowing the setae of sibling valves to protrude outside the diameter of the chain during their formation. C. bacteriastroides and C. pseudocurvisetum are not identical; differences include presence of small setae, fusion of large setae some distance from the valves, symmetry of apertures between cells, and straight chains of C. bacteriastroides, compared with valve mantle connections with no small setae, large setae joined by crossing over, asymmetry of windows between cells, and curved chains of C. pseudocurvisetum. The evolutionary direction is hypothesized to be from Bacteriastrum to Chaetoceros through C. bacteriastroides.
ULTRASTRUCTURE OF THE RED TIDE DINOFLAGELLATE GYMNODINIUM BREVE. I. GENERAL DESCRIPTION1,2,3
Authors: Steidinger Karen A. , Truby Earnest W. , Dawes Clinton J. 
Published: April 2006

ABSTRACT Gymnodimium breve Davis, an unarmored marine dinoflagellate has a cell covering (theca) composed of four membranes. The inner two membranes represent a vesicular layer and in tangential section, the theca appears composed of polygonal areas. Unusual threat ridges are located in the cingular region between the epi‐ and hypocone. This osmotically sensitive species is extremely vesiculate with dispersed areas of cytoplasm containing typical eukaryotic organelles as well as other organelles found only in dinoflagellates. The non‐vesiculated cytoplasm is continuous in serial sections. The chloroplasts can contain either quasi‐radial or parallel lamellae typically consisting of three thylakoids each. The pyrenoid is multiple‐stalked and lacks a starch cap. The dinophycean pusule is simple and similar to those found in several unarmored marine species. The nucleus is typically dinophycean but the chromosomes appear to lack nonfibrillar material.
UPTAKE OF ORGANIC SUBSTRATES BY CYCLOTELLA CRYPTICA (BACILLARIOPHYCEAE): EFFECTS OF IONS, IONOPHORES AND METABOLIC AND TRANSPORT INHIBITORS1,2
Authors: Hellebust Johan A. 
Published: April 2006

ABSTRACTThe uptake of glucose and amino acids by the euryhaline diatom Cyclotella cryptica Reimann, Lewin & Guillard does not appear to be related to proton gradients. Instead, the transport systems for these organic solutes show a strong requirement for the presence of NaCl. The relationship between uptake and NaCl concentration is hyperbolic, with optimal uptake rates being approached at 100 mM NaCl. High concentrations of KCl cause strong reductions in uptake rates. The (Na+, K+)‐stimulated ATPase inhibitor ouabain has no effect on glucose uptake, whereas the diphenolic glucoside phlorizin and its aglucone phloretin are strongly inhibitory. The proton translocating uncoupler CCCP (carbonylcyanide m‐chlorophenyl hydrazone) and the ATPase inhibitor DCCD (dicyclohexylcarbodiimide) both almost completely abolish glucose transport, and low concentrations of the ionophares monensin and valenomycin strongly inhibit glucose uptake by the diatom. The requirement of high external NaCl concentrations for glucose transport, and the inhibitory effect an transport of the Na+‐specific ionophore monensin are consistent with a coupling of Na+ and organic substrate transport, but could also be explained by a Na+ requirement for glucose binding to a transport carrier, and/or a possible interference with energy producing reactions associated with a monensin‐induced collapse of the normal Na+ gradient.
GROWTH OFULVA FENESTRATA(CHLOROPHYTA) IN MICROCOSMS RICH INZOSTERA MARINA(ANTHOPHYTA) DETRITUS1,2
Authors: Harrison Paul Garth 
Published: April 2006

ABSTRACTIn laboratory experiments discs cut from thalli ofUlva fenestrataPostels & Ruprecht grew in diameter and biomass (dry weight and ash‐free dry weight) more when dead leaves ofZostera marina L.were present than when absent. A maximum increase in dry weight of 500% in 14 days occurred withZosterapresent compared with only a 200% increase with no detritus. When NO−3and PO3‐4were added the weight of anUlvadisc increased by over 800% whenZosterawas present but by only 400% in controls. In general penicillin G (475 units/ml) caused a reduction in algal growth in cultures containing detritus. It is concluded that bacteria on the detritus may compete with algae for nutrients but by releasing unknown substances the bacteria promote the growth ofUlva.
ULTRASTRUCTURE OF NOCTILUCA MILIARIS (PYRROPHYTA) WITH GREEN FLAGELLATE SYMBIONTS1,2
Authors: Sweeney Beatrice M. 
Published: April 2006

ABSTRACTThe ultrastructure of the Noctiluca miliaris Suriray from Southest Asian waters which contains the green flagellate, Pedinomonas noctilucae (Subrahmanyan) Sweeney, is in all major respects similar to that of the European strain. New details of the thecal vesicles, pellicle and underlying microtubules are presented. The possibility that the lipid vesicles are identical with the strongly phase‐retarding bodies in the surface cytoplasm, some of which are “microsources” of bioluminescence, is suggested.
MITOSIS AND CYTOKINESIS IN SESSILE SPORANGIUM OFTRENTEPOHLIA AUREA(CHLOROPHYCEAE)1
Authors: Graham Linda E. , McBride Gordon E. 
Published: April 2006

ABSTRACTAn ultrastructure study of mitosis and cytokinesis in the sessile sporangium ofTrentepohlia aurea(L.) Mart, was made to clarify the phylogenetic position of the alga. Mitosis was closed and centric at late anphase with cytokinesis involving the production of cleavage membranes by dictyasames between the numerous, well‐separated daughter nuclei. Neither phycoplast nor phragmoplast microtubules were observed during cytokinesis. The lack of phycoplast microtubules and the presence of multilayered structures in flagellated cells suggestTrentepohliais phylogenetically related to those green algae thought to have given rise to the land plants. The primitive type of mitosis and the lack of microbodies suggest that the ancestors ofTrentepohliamay have branched off from this line relatively early.
DIVERSITY IN THE MECHANISM OF CARBON DIOXIDE FIXATION INDUNALIELLA TERTIOLECTA(CHLOROPHYCEAE)1
Authors: Mukerji D. , Glover H. E. , Morris I. 
Published: April 2006

ABSTRACTThe mechanism of photosynthetic carbon dioxide fixation in the green flagellateDunaliella tertiolectaButcher varies during growth in batch culture. Evidence for this change comes from three sources: i) algae from the stationary phase incorporated a greater proportion of the fixed carbon into amino arids and protein than did cells from the mid‐exponential phase; ii) the activity of phosphoenolpyruvate carboxylase relative to that of ribulose‐1, 5‐di‐phosphate carboxylase increased with age in batch culture; and, iii) cells from the stationary phase appeared to utilize the bicarbonate ion as the substrate for photosynthesis, whereas those from mid‐exponential phase appeared to utilize fire carbon dioxide. These data suggest that a change of photosynthetic mechanism can occur within a single species of alga, depending on its physiological state.
PHYSIOLOGICAL INVESTIGATIONS ON ALARM ESCULENTA (LAMINARIALES. PHAEOPHYCEAE). IV. INORGANIC AND ORGANIC NITROGEN IN THE BLADE1,2
Authors: Buggeln Richard G. 
Published: April 2006

ABSTRACT Seasonal variations in nitrate and organic nitrogen content along the wing and midrib of Alaria esculenta (L.) Grev. lamina have been compared with the NO3‐ cycle in the sea and yearly growth pattern of the blade. Throughout the year, organic N is highest in blade meristem, while NO3‐ distribution is less consistent. NO3‐in blades reaches a peak in March (ca. 25–28 μM), whereas maximum relative accumulation, 3,300X ambient seawater level, occurs in October. Content of NO3‐ and organic N in the blade decreases in concert with the decline of seawater NO3‐ in April. The three periods of rapid blade growth are not correlated with a specific organic N content in the blade meristem. Laboratory experiments suggest that low NO3‐ and elevated seawater temperature are not the major factors retarding Alaria blade growth during summer and early fall in nature.
STUDIES OF HAWAIIAN FRESHWATER AND SOIL ALGAE II. ALGAL COLONIZATION AND SUCCESSION ON A DATED VOLCANIC SUBSTRATE1,2
Authors: Carson Johnny L. , Brown R. Malcolm 
Published: April 2006

ABSTRACT Spatial studies of colonization and succession of soil algae and chemical analyses of the various soils on the cinde cone of Kilauea Iki in Hawaii Volcanoes National Park, Hawaii are outlined. There is a positive correlation between the diversity and quantity of soil algae with nutrient levels and organic matter accumulation in each locale. Three distinct edaphic‐biotic zones existing in this area are differentially revealed by the soil chemical composition, quantity and diversity of soil algae, and as evident variations in higher plant growth and colonization. Varying colonization and successional phases of higher plant growth around standing and fallen tree snags killed by volcanic activity also reflect variations in the soil algal flora. These variations appear largely as a function of differential water interception, absorption, and retention as well as differential accumulation of organic matter, and the initiation of various biogeochemical cycles.
CELL WALL CHEMISTRY AND ULTRASTRUCTURE OF CHLOROCOCCUM OLEOFACIENS (CHLOROPHYCEAE)1,2
Authors: Miller David H. 
Published: April 2006

ABSTRACT Cell walls of Chlorococcum oleofadens Trainor & Bold were examined ultrastructurally and chemically. The wall of zoospores has a uniform 30 nm width and a regular lamellar pattern. Zoospores and young vegetative cell walk exhibit periodicities, consisting of 20 nm ridges on the outer layer. Vegetative cell walls have a variable thickness of Up to 800 nm and are composed of multiple layers of electron dense material. Further, vegetative walk contain a microfibrillar material composed predominantly of glucose and presumed to be cellulose. Except for this cellulose, vegetative cell wall chemistry is very similar to that of Chlamydomemas being composed of glycoprotein rich in hydroxyproline. The hydroxyproline in Chlorococcum walls is linked glycosidically to a mixture of hetrooligosaccharides composed of arabinose and galactose, and in one instance, an unknown 6‐deoxyhexose. Altogether, the glycoprotein complex accounts for at least 52% of the wall. The amino acid composition of the walls is stikingly similar to those of widely different plant species. Indirect evidence indicates zoospore cell walls are also chemically similar to those of Chlamydomonas, and like them, are cellulose free. Thus a major chemical difference between zoospore and vegetative cell walk of Chlorococcum is the presence of cellulose in the latter. The contribution of this microfibrillar cellulose to the physical properties of the vegetative wall is discussed.
AMINO ACID AND UREA UPTAKE IN TEN SPECIES OF CHLOROPHYTA1
Authors: Kirk David L. , Kirk Marilyn M. 
Published: April 2006

ABSTRACT The Uptake of radioartively‐labelled mixed amino acids, arginine, lysine, leucine, glutamic acid and urea was examined in six species of Volvocales and four species of Chlarococcales grown in nitrate‐containing medium. Nonradioactive amino acids in excess were used to estimate specificity of amino and carriers in selected cases. All ten species possess salurable (hence, carrier‐mediated) systems for uptake of both arginine and urea. In all Volvacales and one Chlorococcales, the arginine‐speciftc carrier (which also transported lysine with lower efficiency) was the only amino acid carrier detected. Three species of Chlororoccales appear to possess a separate carrier for lysine and two of these appear to possess at least one additional carrier that is involved in uptake of non‐basic amino acids.
ROLE OF INORGANIC IONS IN CONTROLLING SEDIMENTATION RATE OF A MARINE CENTRIC DIATOMDITYLUM BRIGHTWELLI1,2
Authors: Anderson Lars W. J. , Sweeney Beatrice M. 
Published: April 2006

ABSTRACTThe settling rates and intracellular levels of K+, Na+, Cl‐, Mg2+and Ca2+were measured inDitylum bright‐welli(West) Grunow, grown axenically in an enriched seawater medium at 20 C at 4,000 lx on an 8:16 LD schedule. Cells at the end of the dark period have high Na+(118 mM), low K+(64 mM) and low Cl‐(117 mM) relative to levels at the end of the light period when K+(126 mM) and Cl‐(154 mM) are high and Na+(101 mM) is low. There is no significant change in Mg2+(16–18 mM) or Ca2+(3–4 mM) with time. The net result of the ion changes during the light period is to increase cell density by about 3.4 mg ml‐1. This change can account for the increase in settling rate of ca. 0.3 day‐1during the same interval. The density of the cell contents, calculated from observed ion concentrations, is 15–18 mg.ml‐1less than that of the seawater medium. The ion and settling rate changes are light‐dependent and do not persist in the dark or under constant light (ca. 850 lx), but cells do exhibit a free‐running circadian rhythm in cell division under continuous dim illumination. The cell vacuole expands during the light period and contracts during the dark, apparently in response to the net ion fluxes. D. brightwelliappears to regulate its density by active ion selectivity accompanied by trans‐vacuolar water movement.
POTENTIAL IMPORTANCE OF BENTHIC CYSTS OF GONYAULAX TAMARENSIS AND G. EXCAVATA IN INITIATING TOXIC DINOFLAGELLATE BLOOMS1,2,3
Authors: Anderson Donald Mark , Wall David 
Published: April 2006

ABSTRACT Thick‐walled, nonmotile cysts (termed hypnocysts) of two dinoflagellates were isolated from estuarine sediments in Cape Cod, Massachusetts, and germinated to produce their respective motile, thecate stages. Hypnocysts from Orleans district were identified as Gonyaulax excuvata (Braarud) Balech sensu Loeblich & Loeblich. Visually identical hypnocysts from Falmouth district were provisionally identified as Gonyaulax tamarensis Lebour. Both species were toxic. A geographic survey in September detected hypnocysts in only the sediments of locations where toxic blooms developed the preceding and following Spring. Laboratory incubation (16 C) of hypnocysts from sediment samples stored in the dark (5 C) for 6 mo initiated excystment by the temperature increase, with no appreciable effect from light regime, nutrient, or chelator concentrations. Motility of excysted germlings was optimum in highly chelated medium and in the presence of light. We conclude that hypnocysts of both tasa are important in seeding recurrent annual blooms, synchronizing early bloom development with vernal warning of seawater and increasing the geographic range of the species. We suggest that many red tides in New England and eastern Canadian waters are initiated through the displacement of motile estuarine populations into nearshore area by tidal advection and surface runoff, although the potential existence and importance of offshore cyst reservoirs cannot be discounted. Evidence is presented that hypnocysts are probable sexual zygotes whereas the thin‐walled cysts readily formed in laboratory cultures (pellicle cyst) are asexual. Pellicle cysts are of limited durability, do not overwinter in nature, and therefore do not play a significant role in initiating toxic blooms.
SEXUALITY AND CYST FORMATION IN PACIFIC STRAINS OF THE TOXIC D1NOFLAGELLATEGONYAULAX TAMARENSIS1,2
Authors: Turpin D. H. , Dobell P. E. R. , Taylor F. J. R. 
Published: April 2006

ABSTRACTSexuality has been established for a culture ofGonyaulax tarnarensisLebour (strain NEPCC–71). The addition of a thick inoculum to a nitrogen–deprived medium results in the occurrence of anisogamous sexual fusion within the first three days in the new culture. Planozygotes, large “lumpy” cells recognizable by their four flagella, may persist up to 2 wk before forming a smooth–walled, oval hypnozygote. The latter resembles cysts released asexually by ecdysis but has a slightly thicker wall. Viable cysts resembling hypnozygotes (zygotic cysts), but with reduced photosynthetic pigmentation, have been isolated from natural murine sediments in Hidden Basin, British Columbia, and a culture (strain NEPCC–254) was initiated from excysted individuals. Zygotic cysts of NEPCC–71 remained encysted in the light at 17 C for 8 wk before excysting. The presence of a ventral pen with toxicity in the latter strain indicates that the taxonomy ofG. tamarensis‐like organisms is still in a stale of flux and the criteria for recognition ofG. excavata (Braarud) Balech as a separate species are not satisfactory as presently formulated.
COMPARATIVE PHYSIOLOGICAL STUDY OF MARINE DIATOMS AND DINOFLAGELLATES IN RELATION TO IRRADIANCE AND CELL SIZE. I. GROWTH UNDER CONTINUOUS LIGHT1,2
Authors: Chan Augustine T. 
Published: April 2006

ABSTRACT Cell division rates and chlorophyll a and protein contents for ten diatom and dinoflagellate species were measured. Species were chosen to include a wide range of cell size in terms of both cell volume and cell protein: from 0.004 ng protein/cell for a small Chaetoceros sp. to 2.2 ng protein/cell for Prorocentrum micans Ehrenberg. Experiments were conducted in batch or semi‐continuous cultures at 21 C under continuous illumination from 8–256 μEin .m‐2'.s‐1. Light saturation of cell division occurred at 32–80 μEin m‐1 s‐1 for all species, with no observable difference between the two phylogenetic groups. When the light‐saturated cell division rates were plotted against cell size as protein/cell, the diatoms and dinoflagellates fell on two separate lines with the diatoms having higher rates. Chl a /protein ratios (μg/μg) decreased with increasing irradiance. The diatoms had higher chl a per unit protein. The relationship between cell division rate and the chl a/protein ratio is discussed.
QUALITATIVE ASSAY OF DISSOLVED AMINO ACIDS AND SUGARS EXCRETED BYCHLAMYDOMONAS REINHARDTII(CHLOROPHYCEAE) ANDEUGLENA GRACILIS(EUGLENOPHYCEAE)1
Authors: Vogel Stephanie L. , Frisch Harry L. , Gotham Ivan J. 
Published: April 2006

AbstractDissolved amino acids and sugars produced byChlamydomonas reinhardtii Dangeard and Euglena gracilisKlebs were assayed using a combination of radiochromatography and membrane separated spinner flasks. Both species produced similar complements of sugars. The sugars produced In the algae included galactose, glucose, maltose and xylose. The amino acid complements produced Were different for each species. C. reinhardtiiexcreted aspartate, leucine, methionine, phenlyalanine, tyrosine and Valine. E. gracilisexcreted alanine, glutamate, proline and serine. Separation of cells from growth media via membrane filtration produced an overestimate of net amount of dissolved carbon compounds excreted by the cells. However, the radiochromatographic spectra for both filtrates and cell‐free compartments of the diffusion flask experiments were identical. It is hypothesized that the process of filtration max enhance leakage of labeled cellular pools rather than cellular disruption in the species investigated.
FIELD AND CULTURE STUDIES ONGIGARTINA AGARDHII(RHODOPHYTA)1,2
Authors: West John A. , Polanshek Alan R. , Shevlin Dennis E. 
Published: April 2006

ABSTRACTCultured carpospores from field‐collected plants ofGigartina agardhiiSelfchell & Gardner gave rise to eitherPetrocelis‐like crustose plants, or basal discs with erectGigartina‐like blades. Made tips excised from field‐collected female plants and cultured in the laboratory also showed two patterns of reproduction: procarpic papillae that only produced cystocarps in the presence of male plants with spermatid, or cystocarpic papillae that formed and released carpospores in the absence of male plants. The first pattern in each case above is evidence for a sexual life history and the second for an apomictic life history similar to that forG. papillata (C. Agardh) J. Agardh. The resorcinol lest for k‐carrageenan was negative forPetrocelis‐like plants and positive for foliose plants providing addition evidence that the former are haploid and the latter diploid as is characteristic for the Gigartinaceae. Crossing experiments between sexual male and female isolates ofG. agardhii fromseveral locations indicated that free interbreeding occurs. All crosses betweenG. agardhiiandGigartina‐phase gametophytes cultured from tetraspores ofPetrocelis middendorffii (Ruprecht) Kjellman were negative demonstrating thatG. agardhiiis reproductively isolated fromG. papillata/P. middendorffiiand represents a distinct species. The tetrasporophytic phase of G. agardhiiin nature is still not known. The significance of reproductive isolation inGigartinasubgenusMastocarpusis discussed. On the bosis of nomenclatural priorityG. agardhiiSetchell & Gardner 1933 is placed in synonymy underG.jardiniiJ.Agardh 1876.
DIFFERENCES IN PHOTOSYNTHESIS‐ASSOCIATED PROPERTIES OF THE BLUEGREEN ALGA SYNECHOCOCCUS CEDRORUM CROWN AT 30 AND 40 C1
Authors: Sherman Louis A. 
Published: April 2006

ABSTRACT The growth of Synechococcus cedrorum Saug. (UTEX 1191) at 40 C resulted in structural and functional alteratons relative to cells grown at 30 C. Structural variations included cell morphology and the chemical composition of the membrane. Growth at 40 C. produced cells that were longer and thinner than those at 30 C. The fatty acid composition changed substantially upon growth at 40 C. yielding a distribution with a higher ratio of: i) saturated to unsaturated fatty acids and; ii) longer chain unsaturated fatty acids. Furthermore, the pattern of membrane proteins as determined by sodium dodecyl sulfate electrophoresis was distinctly different. The functional changes were typified by photosynthetic rates which were approximately half those of the 30 C grown cells. A number of spectral parameters were also seen to change in 40 C. grown cells: absorption spectra indicated a higher phycocyanin : chlorophyll ratio. Low temperature fluorescence spectra were consistent with a lowered efficiency of energy transfer from phycocyanin to chlorophyll. It is suggested that the fatty acid changes at 40 C. yield a more fluid membrane which is responsible for the functional alterations. The modification of phycocyanin. chlorophyll ratios, as well as the appearance of P750, is discussed with respect to membrane fluidity.
INFLUENCE OF TRICHOME LENGTH ON LINEAR TRANSLATION INOSCILLATORIA PRINCEPS(CYANOPHYCEAE)1
Authors: Halfen Lawrence N. , Halfen Mary E. 
Published: April 2006

ABSTRACTMotile trichomes ofOscillatoria princepsVoucher were examined to determine the relationship between trichome length and the ability to glide through hardened or viscous media. A minimum length for movement in solid media was found to be 0.1 mm in 0.5% agar (w/v).Viscous media tests revealed that coordinated movements through methyl cellulose media were not seen in trichomes 15–40 μ long at the viscosity employed. The minimum length motility increases with the viscosity of the medium and the gliding rates observed are greater in longer trihomes. These findings are discussed in relation to trichome surface area and the hypothesis that the motility system is restricted to lateral surfaces of the trichome.