bluuebunny/crossref_metadata_2025_split huggingface dataset:
FREEZE‐FRACTURE STUDY OF THE SINGLE MEMBRANE BETWEEN HOST CELL AND ENDOCYTOBIONT IN THE DINOFLAGELLATESGLENODINIUM FOLIACEUMANDPERIDINIUM BALTICUM1
Authors: Eschbach Stefan , Speth Volker , Hansmann Paul , Sitte Peter 
Published: October 2004

ABSTRACTThe dinoflagellatesGlenodinium foliaceumStein andPeridinium balticum(Levander) Lemmermann harbor a chrysophytic endocytobiont which is bounded by only a single membrane. This unique membrane is of particular interest because it could correspond to an intermediate stage in the evolution of “complex” plastids found in many Plastids of this type are surrounded by three or membranes instead of the usual two. With freeze‐fracture techniques, we show that the single membrane inP. balticumhas a pronounced polarity with respect to the distribution of intramembrane particles (IMPs) on the two corresponding fracture faces. The inner face exhibited more IMPs than the outer. We suggest that this stdedness identifies the separating membrane as the plasma membrane of the endocytobiont. A symbiontophoric vacuole with a separate membrane apparently is lacking. In the endocytobiosis ofG. foliaccum,the single membrane separating host and endocylobiont exhibits a symmetrical particle partition. Nevertheless, from the size distribution of the IMPs it appears likely that this membrane, too, corresponds to the plasma membrane of the symbiont.
RESTRICTION ENZYME ANALYSIS AND CLONING OF HIGH MOLECULAR WEIGHT GENOMIC DNA ISOLATED FROM CHLORELLA SOROKINIANA (CHLOROPHYTA)1
Authors: Cock J. Mark , Roof Lori L. , Boscomb Newell F. , Gehrke Charles W. , Kuo Kenneth C. , Schmidt Robert R. 
Published: October 2004

ABSTRACTHigh molecular weight (50–70 kb) genomic DNA was isolated from the eukaryotic green alga, Chlorella sorokiniana spec. nov, (formerly Chlorella pyrenoidosa Chick, strain 7‐11‐05), for restriction endonuclease digestion studies and for preparation of a genomic DNA library. Twenty restriction endonucleases were examined for their abilities to digest this DNA. Nine of the endonucleases gave nearly complete digestion of the DNA, whereas 11 gave only partial digestion. Additional purification steps to remove possible contamination by proteins, RNAs, or polysaccharides did not improve digestion. Digestion studies with pairs of endonuclease isoschizomers, of which one member was sensitive to base methylation, suggested that 5‐methylcytosine might be responsible Jor inhibition of certain endonucleases. Analysis of the DNA showed it to contain 63% GC and to have a high content (5.1 mol %) of 5‐methylcytostne but no other methylated or unusual bases. Evidence indicates that this high 5‐methylcytosine content, which is a characteristic of higher plant genomic DNA rather than of eukaryotic microorganisms, interfered with the cloning of restriction fragments (or fragments produced by mechanical shearing) of C. sorokiniana genomic DNA in standard bacterial host‐strains. Escherichia coli strain K803, which is a permissive host for cloning highly methylated DNA from higher plants, also permitted the cloning of a complete genomic library of 15–20 kb Mbol restriction fragments inserted into the BamHI site of the γ vector, EMBL 3. This C. sorokiniana genomic library appears to be the first genomic‐library constructed for any species of Chlorella.
OCCURRENCE OF GLYCOLATE OXIDASE AND HYDROXYPYRUVATE REDUCTASE IN EGREGIA MENZIESII (PHAEOPHYTA)1
Authors: Gross Wolfgang 
Published: October 2004

ABSTRACTGlycolate oxidase and hydroxypyruvate reductase, two key enzymes of glycolate metabolism, are present in the brown alga Egregia menziesii (Turn.) Aresch. The pH optimum and Km for the partially purified glycolate oxidase are similar to the enzyme from higher plants, Charophyta and Xanthophyta, whereas the substrate specificity is different from the higher plant enzyme.
EFFECTS OF WOUNDING BY THE HERBIVOROUS SNAILS LITTORINA SITKANA AND L. SCUTULATA (MOLLUSCA) ON GROWTH AND REPRODUCTION OF THE INTERTIDAL ALGA FUCUS DISTICHUS (PHAEOPHYTA)1
Authors: Van Alstyne Kathryn L. 
Published: October 2004

ABSTRACTSmall (3–7 cm long) Fucus distichus ssp. edentatus (de la Pyl.) Pow. Plants were tagged at three sites in which densities of the herbivorous snails Littorina sitkana and L. scutulata ranged from 367–4690 animals · M‐2. From April–August 1986, the growth rate, degree of wounding, and reproductive status of individual thalli were monitored at 2–4 week intervals. Grazer‐inflicted damage to the thalli varied within and among sites. Mean growth rates at the site with low densities of littorines were about twice those at the site with intermediate densities and about four times those at the high density site. At the site with high densities of littorines, F. distichus growth rates were negatively correlated with the degree to which the plants were wounded. There appeared to be no correlation of grazer density with F. distichus survivorship. Thalli at the site with few herbivores tended to reproduce earlier and at a larger size than did those at the other two sites. In all three areas, only thalli that had received little damage from herbivores became reproductive. By lowering growth rates and delaying reproduction in F. distichus, grazing by littorine snails can potentially cause variation in reproductive output among individual thalli.
INTERTIDAL AMPHIPODS AS POTENTIAL DISPERSAL AGENTS OF CARPOSPORES OF IRIDAEA LAMINARIOIDES (GIGARTINALES, RHODOPHYTA)1
Authors: Buschmann Alejandro H. , Bravo Andrés 
Published: October 2004

ABSTRACTMid and late successional benthic algae have poor dispersal capacities. Mobile herbivores may increase dispersal of some algae because spores can survive digestion by grazers and stick to external body appendages. We show that carpospores are the only type of reproductive unit of the rhodophyte Iridaea laminarioides Bory that survive passage through the digestive tract of the amphipod Hyale sp. The spores also stick to the amphipods' legs and are thus carried by the amphipods in the field. Amphipods significantly increased (P < 0.01) the number of spores settling on artificial substrata in places where barriers prevented the normal ingress of algal propagules. The presence of artificial substrata that act as a refuge for the grazers also caused an increase (P < 0.01) in the number of settled spores. Amphipods also significantly increased (P < 0.01) the number of spores under an Ulva sp. canopy in laboratory experiments.
EXOGENOUS SOURCES OF INORGANIC CARBON FOR PHOTOSYNTHESIS BY MARINE MACROALGAE1
Authors: Maberly Stephen C. 
Published: October 2004

ABSTRACTThirty‐five species of marine macroalgae were tested for their ability to remove inorganic carbon from seawater using the pH‐drift technique. Six of these species, all Rhodophyta, were unable to use HCO3–. The remaining species exhibited a range in ability to use HCO3– and deplete inorganic carbon (Cτ); the three most effective species, all Chlorophyta, raised the pH to over 10.50, depleted the concentration of CO2 effectively to zero, and depleted the concentration of Cτ to less than 50% of that at air‐equilibrium. In contrast, the six species restricted to CO2 did not raise the pH above 9.0 at a CO2 concentration of about 1.5 μmol · L‐1 and depleted the concentration of Cτ to about 80% of that at air‐equilibrium.Ability to raise pH and deplete Cτ was linked to the habitat in which the species grew. Five of the six species which lack the ability to use HCO3– grow subtidally in relatively low light beneath a canopy of larger Phaeophyta. None of these species grow in rockpools where carbon‐depletion may occur. Species from rockpools were all effective at removing inorganic carbon. Competition for Cτ may be one of the factors that determines species composition in rockpools.There was a species‐specific difference between the calculated concentration of Cτ at the end of a pH‐drift experiment and that measured directly. Most, but not all, species with the ability to generate high pH‐values showed a lower than calculated final concentration of Cτ consistent with precipitation of CaCO3. A number of Rhodophyta with no, or a limited, ability to use HCO3– showed the opposite response, with final concentrations of Cτ exceeding that calculated from the pH.Calculations based on the maximum gross rate of production of CO2 from HCO3– in the absence of external carbonic anhydrase confirmed the results of the pH‐drift experiments by demonstrating HCO3– ‐use in Monostroma fuscum (Post et Rupr.) Wittr. And Ulva lactuca L. and the lack of this ability in Lomentaria articulate (Huds.) Lyngb. Rates of net photosynthesis at air‐equilibrium were greater than 95% of those at 2.3 mmol Cτ· L‐1 for many of the species which were able to use HCO3–, but on average only 72% for the six species restricted to CO2.
EFFECTS OF LIGHT AND WAVE DISTURBANCE ON VERTICAL ZONATION OF ATTACHED MICROALGAGE IN A LARGE RESERVOIR1
Authors: Hoagland Kyle D. , Peterson Christopher G. 
Published: October 2004

ABSTRACTExperimental field manipulations of artificial substrata were used to examine the mechanisms controlling attached algal zonation down the face of the dam in Lake McConaughy, a large reservoir in western Nabraska. Sets of clay tiles were incubated in the upper (2.5 m depth) and lower (8 m depth) growth zones for two weeks. Five sets tiles were then switched from the upper to the lower growth zone and vice versa. Five additional sets of tiles were switched to the lower zone and artificially disturbed. Diatom cell densities increased rapidly in both the zones; however, wind‐induced turbulence caused dramatic declines (up to 61%) in densities in the upper zone. Consequently, cell densities in the upper and lower growth zones were not significantly different after four weeks, despite the 17–30% higher light levels in the upper zone. Based on cell densities and relative abundances on clay tiles and naturally occurring rocks, 26 of the 32 most common diatom taxa had a significant upper (10) or lower (16) zone preference. Of these, 15 taxa exhibited a consistent response to one or both switching manipulations, confirming a growth zone preference, and two showed a clear preference for disturbed substrata. Diatom growth form appeared to play a major role in determining the vertical zonation of attached communities, since actively motile taxa exhibited a lower zone preference and stalked forms occurred primarily in the upper zone. The present study indicates that light attenuation and wave disturbance are primary mechanisms that control the vertical zonation of freshwater epilithic algae.
DISTRIBUTION AND ALGAL‐LYSING ACTIVITY OF FRUITING MYXOBACTERIA IN LAKE SUWA1
Authors: Yamamoto Yoko , Suzuki Kenji 
Published: October 2004

ABSTRACTThe seasonal distribution of fruiting myxobacteria, which are able to lyse cyanobacteria in the water and sediments of eutrophic lakes, was determined periodically in 1985 and 1986. Fruiting myxobacteria isolated from sediments of these sites were found to have a lytic effect on a wide variety of cyanobacteria. The myxobacterium isolate designated as S‐1‐8 was identified as Myxococcus fulvus Cohn. Lytic activity for cyanobacteria was produced during growth of the organism in a number of complex media. The maximal amount of activity was produced in casitone‐yeast media and at the end of the log phase of growth.
EFFECTS OF LONG TERM EXPOSURE TO LOW TEMPERATURE ON THE PHOTOSYNTHETIC APPARATUS OFDUNALIELLA TERTIOLECTA(CHLOROPHYCEAE)1
Authors: Levasseur Maurice E. , Morissette Jean‐Claude , Popovic Radovan , Harrison Paul J. 
Published: October 2004

ABSTRACTThe effects of long term exposure to suboptimal growth temperature on the photosynthetic apparatus ofDunaliella tertiolectaButcher were investigated using carbon fixation rate versus irradiance curves and the variable fluorescence induction method. Carbon fixation rates per unite chlorophyll a at saturating (pBm) and subsaturating (αB) irradiances were 55% and 39% lower, respectively, at 12° C than at 20° C. Chlorophyll a quotas and the spectrally averaged in vivo absorption cross section normalized to chlorophyll a (a*) were not significantly different at these two temperatures. Analysis of the fluorescence kinetics revealed 1) no significant variations of the amount of PSII photoactive reaction centers per unit chlorophyll a, 2) a 14% decrease of the PSII quantum yield(+) and 3) a 29% decrease of the energy transfer efficiency between the light harvesting chlorophyll a pigment bed and the PSII reaction centers. The decrease in energy transfer efficiency between the antennae and the PSII reaction centers at 12° C was interpreted as a mechanism to avoid photoinhibition.
STEROLS OF DICTYOCHA FIBULA (CHRYSOPHYCEAE) AND OLISTHODISCUS LUTEUS (RAPHIDOPHYCEAE)1
Authors: Patterson Glenn W. , Van Valkenburg Shirley D. 
Published: October 2004

ABSTRACTSterols from cultured Dictyocha fibula Ehrenberg and Olisthodiscus luteus Carter were extracted and identified for comparison with sterols from other Chromophycota species. Although orientation at C‐24 was not absolutely determined, the sterols of Dictyocha, a silicoflagellale, appeared to consist of only 24‐methyl‐22‐dehydrocholesterol and 24‐methylenecholesterol, a sterol composition not known in any other alga. This is in keeping with the taxonomic isolation Dictyocha has among algae. On the other hand, Olisthodiscus luteus contained 24‐ethylcholesterol, 24‐ethylcholestanol, 24‐methylcholesterol, and cholesterol. This composition is in accord with sterols of members of the Xanthophyceae and Raphidophyceae.
UNIQUE CHLOROPLAST GENOME IN SPIROGYRA MAXIMA (CHLOROPHYTA) REVEALED BY PHYSICAL AND GENE MAPPING1
Authors: Manhart James R. , Hoshaw Robert W. , Palmer Jeffrey D. 
Published: October 2004

ABSTRACTThe choroplast genome in Spirogyra maxima (Hassall) Kützing is 130 kb in size and locks large repeat units. The 16S and 23S rRNA genes are separated by approximately 44 kb, which makes co‐transcription of these genes unlikely. Spirogyra maxima is unusual among green algae in that its chloroplast genome apparently does not contain the tufA gene, the absence of which is characteristic of land plant chloroplast DNAs. Apart from three groups of genes, pasA‐psaB, psbC‐psbD, and atpA‐atpF/H, which are co‐transcribed in land plants and also map together in S. maxima chloroplast DNA, the S. maxima gene order overall is unlike that of any other chloroplast genome.
PLASTID DNA RESTRICTION ANALYSIS LINKS THE HETEROMORPHIC PHASES OF AN APOMICTIC RED ALGAL LIFE HISTORY1
Authors: Parsons Thomas J. , Maggs Christine A. , Douglas Susan E. 
Published: October 2004

ABSTRACT Gymnogongrus sp. (Phyllophoraceae) from Nova Scotia, Canada, identified tentatively as G. devoniensis (Greville) Schotter, grows in association with an Erythrodermis‐like that forms chains of tetrasporangia or bisporangia. The crust resembles tetrasporophytic phases of other Gymnogongrus species, but in culture both it and the G. devoniensis gametophytes cycle independently by apomictic reproduction.A method was developed for extracting organelle DNA from this carrageenophyte genus involving purification of nucleic acids by binding to hydroxylapatite. Plastid DNA from G. devoniensis and bisporangial Erythrodermis‐like crusts was compared with that of G. devoniensis and G. crenulatus (Turner) J. Agardh from France and of G. furcellatus (C. Agardh) J. Agardh from Chile. Plastid genomes of all Gymnogongrus species and the Erythrodermis‐like crust were approximately 175 kb long. A single 3.5‐kb plasmid DNA species was found in G. devoniensis and the Erythrodermis‐like bisporophyte but not in other samples. Digestion of plasted DNA with several restriction endonucleases produced identical patterns in G. devoniensis and the Erythrodermis‐like bisporophyte from the same location, indicating clearly that these entities represent two phases of an uncoupled life history. These results were confirmed with heteologous probes. A restriction fragment length polymorphism was identified between two Nova Scotian G. devoniensis populations. There was no similarity in restriction patterns between G. devoniensis from Nova Scotia, G. devoniensis from France. G. crenulatus or G. furcellatus, suggesting that molecular taxonomic methods could be important in delineating members of this morphologically variable genus. Further study is necessary to determine whether either Nova Scotian G. devoniensis or French G. devoniensis corresponds to type populations of G. devoniensis from Devon, England.
NUCLEOTIDE SEQUENCE OF THE GENE FOR THE LARGE SUBUNIT OF RIBULOSE‐1.5‐DISPHOSPHATE CARBOXYLASE/OXYGENASE FROM CRYPTOMNASΦ EVIDENCE SUPPORTING THE POLYPHYLETIC ORGIN OF PLASTIDS1
Authors: Douglas Susan E. , Durnford Dion G. , Modern Clifford W. 
Published: October 2004

ABSTRACTThe Chloroplast‐encoded gene for the large subunit of ribulose‐1, 5‐bisphosphate carboxylase/oxygenase (Rubisco) from the marine chlorophyll c2‐, phycobiliprotein‐containing alga, Cryptomonas φ was cloned, sequenced and compared to representatives from other groups of photosynthetic organisms. The coding sequence was 1464 base pairs(bp) and encoded a polypeptide of 488 amino acids. The small subunit of Rubisco was located 83 bp 3′ to the large subunit and was co‐transcribed. A 5 bp sequence, 5′ of the initiator methionine codons of both the large and small subunits, may represent ribosomal binging sites. The start of transcription was identified by primer extension studies and putative promotor sequences were found. This study is the first report of the sequence for the large subunit of Rubisco from a chromophyte alga, and its potential as phylogenetic indicator for algal plastids sis discussed.
SPATIAL VARIATION PATTERNS IN THE MARINE MACROALGAXIPHOPHORA GLADIATASSP. GLADIATA (PHAEOPHYTA). I. PARTITIONING OF MORPHOLOGICAL CARIATION INTO SPATIAL SCALES1
Authors: Rice Ellen L. , Kenchington Trevor J. 
Published: October 2004

ABSTRACTThe geographic expression of morphological variation inxiphophora gladiatassp.gladiatawas examined throughout the range of the taxon. The spatial scales on which this variation occurred were identified using nested analyses of variance (ANOVA) on 14 morphometric characters from 1224 plants collected at 12 sites. These characters were remarkably homogeneous in the scales at which their variation was expressed. The greater part of the morphological variation inX. gladiatassp.gladiata(over 90% for most characters was expressed between adjacent primary clumps; that is, over scales of about 100 mm. Since it was previously shown that the clumps of plants are themselves spatially discrete, the spatial expression of morphology in this taxon forms a true mosaic with abrupt between‐cells boundaries. Much of the remaining variation in most characters was expressed at a scale of about 300 km. At intermediate scales, that is, over a few meters and (in most characters) a few kilometers, there appears to be negative additional variance. In effect, the mixture of clumps at these scales tends to be a uniform rather than a random selection of the available morphological variety of clumps within each region. This observed pattern is compared and contrasted with those previously found in the confamilial speciesFucus distichusandF. evanescens.
SPATIAL VARIATION PATTERNS IN THE MARINE MACROALGA XIPHOPHORA GLADIATA SSP. GLADIATA (PHAEOPHYTA). II. MORPHOLOGICAL VARIATION OVER LARGE SPATIAL SCALES1
Authors: Rice Ellen L. , Kenchington Trevor J. 
Published: October 2004

ABSTRACTThe geographic expression of inter‐regional morphological variation in Xiphophora gladiata ssp. gladiata was examined using a combination of discriminant function analyses, canonical correlation analysis and linear regression analysis. The pattern of that expression is an irregularly‐stepped cline over scales of hundreds of kilometers, superimposed on a weak complex of microclines driven by exposure and (perhaps) other locally‐varying environmental factors. The large‐scale irregular cline is probably a response to the physico‐chemical characteristics of regional water masses.
LAGERHEIMIA HINDAKII IS THE UNICELLULAR STAGE OF A SCENEDESMUS1
Authors: Trainor Francis R. , Egan Patrick F. 
Published: October 2004

ABSTRACTExtensive variability in spine number and position was emphasized in the protologue for the spiny unicell Lagerheimia hindakii Hegew. et A. Schmidt. Using an axenic clone established from culture Hindk 1975/95, which provided the type material of that organism, we initiated a morphogenetic study. While in the unicellular stage, three short spines were usually formed at each cell pole. A colonial morph was first observed during the initial isolation procedure after unicells were dispersed on firm agar and allowed to grow. We propose that L. hindakii is a Scenedesmus, close to S. subspicatus R. Chod. This organism is unlike most representatives of the genus Scenedesmus because colonies do not readily appear in dilute media; they also fail to form in Bristol's liquid medium unless there is an organic supplement, e.g. glucose. Hindk 1975/95 may be more closely related to truly unicellular taxa than to other Scenedesmus.
MORPHOLOGIC DETAILS OF SIX BENTHIC SPECIES OF PROROCENTRUM (PYRROPHYTA) FROM A MANGROVE ISLAND, TWIN CAYS, BELIZE, INCLUDING TWO NEW SPECIES1
Authors: Faust Maria A. 
Published: October 2004

ABSTRACTTwo new dinoflagellate species, Prorocentrum hoffmannianum and Prorocentrum ruetzlerianum, and four known species, Prorocentrum emarginatum Fukuyo 1981, Prorocentrum mesicanum Tafall 1942, Prorocentrum concavum Fukuyo 1981, and Prorocentrum lima (Ehr.) Dodge 1975, from floating detritus and sediments in a subtropical mangrove island, Twin Cays, Belize, Central America are described from scanning electron micrographs. Differences in the following characters of surface micromorphology separated the species: ornamentation of thecal plates (shape, size, and number of valve pores and areolae) and the architecture of the periflagellar area and intercalary band.
LIFE HISTORY AND TAXONOMY OF RHIZOOCHROMONAS ENDOLORICATA GEN. ET SP. NOV., A NEW FRESHWATER CHRYSOPHYTE INHABITING DINOBRYON LORICAE1
Authors: Nicholls Kenneth H. 
Published: October 2004

ABSTRACTThe life cycle of a previously undescribed chrysophyte, assigned to the new genus Rhizoochromonas, is described. It includes a small motile stage with heterokont flagellation which invades a Dinobryon lorica. Reproduction by cell division of the nearly spherical rhizopodial vegetative stage frequently leads to expulsion of the host protoplast through overcrowding of the lorica. Endogenous cysts (stomatocysts) are also formed within the Dinobryon lorica. The new family, Brehmiellaceae, is established to accommodate pseudopodial/rhizopodial chrysophytes with heterokont flagellation in the motile stage. Rhizoochromonas endoloricata gen. et sp. nov. has been found at two widely separated softwater locations in Ontario, and at one it constituted a major component of the planktonic flora during the autumns of six successive years.