bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEASONAL PERIODICITY OF CHRYSOPHYCEAE AND SYNUROPHYCEAE IN A SMALL NEW ENGLAND LAKE: IMPLICATIONS FOR PALEOLIMNOLOGICAL RESEARCH1
Authors: Siver Peter A. , Hamer Josephine S. 
Published: October 2004

ABSTRACTThe seasonal periodicity of taxa of Chrysophyceae and Synurophyceae from a small New England lake is described for the period September 1983 through June 1988. We found 51 taxa, including 29 that accounted for over 10% of the total in at least one collection. The taxa were fitted into one of five seasonal patterns. Patterns I and II represented taxa restricted to warm (pattern I) or cold (pattern II) months, respectively. Pattern HI represented organisms that began growth in the summer, persisted through autumn and disappeared with the onset of an ice cover. Pattern IV was an extension of pattern III, in which the taxon remained in the plankton throughout the winter and disappeared soon after ice out. Species without a clear seasonal pattern were grouped as pattern V. The seasonal periodicity of the flora, as examined with ordination analyses, was found to remain remarkedly similar during the 58–month study. Except for episodes of low pH during spring snow melt and unseasonally warm or cold weather, sample scores followed a fairly consistent pattern along the first and second primary axes. Water temperature, specific conductance, and pH were important variables that controlled changes in the species composition during the course of a given year. The flora was used to develop an inference model for water temperature. According to the analyses, the remains of a surface sediment sample represented a flora that grew primarily during the late autumn period at 7.6 ° C. Ways in which seasonal data could be utilized to improve paleolimnological inference work are discussed.
SIZE HIERARCHY AND THE −3/2 “POWER LAW” RELATIONSHIP IN A COALESCENT SEAWEED1
Authors: Martínez Enrique , Santelices Bernabé 
Published: October 2004

ABSTRACTThe size structure of plant populations has been characterized by two descriptors, size‐density relations and size inequality. In even aged natural or experimental populations, the logarithm of mean size is a negative function of population density, with a slope of –3/2 and a maximum intercept of 4.3. Size inequality, measured by the Gini coefficient (G.C.), ranges from maximum size homogeneity (G.C. = 0) to maximum inequality (G.C. = 1). These two descriptors have been applied mainly to land plants, and only once have they been empirically related, suggesting that the onset of self‐thinning (increase in mean size by decreasing density) reduces size inequality. We applied these descriptors and tested their empirical relations within populations of Iridaea laminarioides Bory, a red alga that, as other members of the Gigartinales and Gracilariales, exhibits coalescence of germinating spores, forming a clump of fronds with a single basal disc. Results indicate 1) lack of fit to the self‐thinning rule and transgression of the limit slope, 2) high size inequality values, 3) absence of a significant negative correlation between mean size and Gini values, 4) spatial ordering in the distribution of size inequality, with fronds decreasing in size towards the periphery of the coalescing discs, and 5) reproduction occurring mostly in the large sized fronds. In I. laminarioides transgression of the self‐thinning slope and high size inequality seems to result from spore coalescence and a growth pattern that allows the coalescing discs to grow into physiologically integrated fronds, the larger (and central) of which become reproductive. Therefore, rather than being considered exceptional, we suggest that transgression to the limit slope and high size inequality should be common among seaweeds with coalescing spores and physiological integration of individuals.
EFFECTS OF TURBULENCE ON THE MARINE DINOFLAGELLATE GYMNODINIUM NELSONII1
Authors: Berdalet Elisa 
Published: October 2004

ABSTRACTLaboratory experiments were conducted to study the effects of agitation on growth, cell division, and nucleic acid dynamics of the dinoflagellate Gymnodinium nelsonii Martin. When cultures were placed on an orbital shaker at 100 rpm, cell division was prevented, cellular volume increased up to 1.5 times that of the nonperturbed cells, the form and location of the cell nucleus were modified, and the RNA and DNA concentrations per cell increased up to 10 times those of the controls. When shaking was stopped after 10 days, cells divided immediately at about 2/3 of the division rate of the unshaken populations, and all the altered parameters were restored. If the agitation continued for more than 20 days, total cell death and disintegration occurred. Several cellular types differing in size and shape were observed in the control and shaken cultures. One possible hypothesis for these results is that failure of the cell to divide results from physical disturbance of the microtubule assemblage associated with chromosome separation during mitosis. My study suggests that small‐scale oceanic turbulence of sufficient intensity may inhibit growth of individual dinoflagellate cells, but immediate development of the population may continue when calm weather follows the active mixing period.
CYTOPLASMIC BIOSYNTHESIS OF LIGHT‐HARVESTING POLYPEPTIDES IN THE GREEN FLAGELLATE MANTONIELLA SQUAMATA (MICROMONADOPHYCEAE)1
Authors: Lee Connie M. , Osterbauer Nancy , Jiao Shuping , Fawley Marvin W. 
Published: October 2004

ABSTRACTThe biosynthesis of the light‐harvesting complex (LHC) polypeptides of the green flagellate Mantoniella squamata (Manton et Parke) Desikachary (Micromonadophyceae, Chlorophyta) was examined by in vivo polypeptide labeling and immunoprecipitation of in vitro translation products. Using protein synthesis inhibitors, the LHC polypeptides were shown to be synthesized on 80S cytoplasmic ribosomes and not in the chloroplasts of cells. Poly (A)+ RNA was isolated and proteins were synthesized by a rabbit reticulocyte lysate system, with antisera raised against M. squamata LHC used for immunoprecipitation from the translation products. One polypeptide 3‐5 kDa larger than mature LHC polypeptides was immunoprecipitated. These studies indicate that although the LHC of M. squamata is quite different from the LHC of most green plants, the LHC polypeptides are synthesized as precursors in the cytoplasm of the cell and suggest that the genes encoding these polypeptides are located in the nucleus.
MONOCLONAL ANTIBODIES AS MOLECULAR MARKERS FOR THE INTRACELLULAR AND CELL WALL DISTRIBUTION OF CARRAGEENAN EPITOPES IN KAPPAPHYCUS (RHODOPHYTA) DURING TISSUE DEVELOPMENT1
Authors: Vreeland Valerie , Zablackis Earl , Laetsch Watson M. 
Published: October 2004

ABSTRACTCarrageenan, the major cell wall carbohydrate of certain red algae, is variable in structure and gelling properties. Sequence types include gelling (kappa and iota) and nongelling (lambda) types in addition to precursors, often in hybrid molecules containing more than one precursor and/or sequence type. Molecular markers to subunits were needed to study carrageenan synthesis, cell wall organization, and the relationship between structure and function. Monoclonal antibodies were produced to carrageenan, and their specificities were determined by competitive enzyme immunoassay. Antibodies were identified with specificities related to kappa, iota, and lambda carrageenan. The patterns of immunofluorescence localization on Kappaphycus alvarezii = Eucheuma alvarezii var. tambalang (Doty) sections were distinctive for each antibody. The antibody to a kappa‐related epitope labeled mature tissue strongly; antibodies to an iota‐related epitope and a lambda‐related epitope labeled weakly, consistent with the kappa‐enriched carrageenan produced by this alga. Kappa‐related epitopes were distributed throughout the wall and matrix, whereas iota‐related epitopes were concentrated in the middle lamella. Lambda‐related epitopes were localized primarily at the plant cuticle where kappa and iota antigens were lacking. An antibody appeared to be specific for a precursor of the gelling subunits because it showed maximal wall and intracellular labeling at the youngest developmental stage. All antibodies labeled intracellular inclusions in the transition zone between the epidermis and medulla during the development of medullary cells from the peripheral meristem in young branches. The results demonstrate the intracellular synthesis of epitopes related to all major carrageenan subunits and their differential extracellular distribution.
PHYLOGENY OF CARTERIA (CHLOROPHYCEAE) INFERRED FROM MOLECULAR AND ORGANISMAL DATA1
Authors: Buchheim Mark A. , Chapman Russell L. 
Published: October 2004

ABSTRACTComparative ultrastructural data have shown that at least two distinct groups exist within Carteria. Similarly, interpretations of variation in gross morphological features have led to the discovery of morphologically distinct groups within the genus. Partial sequences from the nuclear‐encoded small‐ and large‐subunit ribosomal RNA molecules of selected Carteria taxa were studied as a means of 1) testing hypotheses that distinct groups of species exist within the genus and 2) assessing monophyly of the genus. Parsimony analysis of the sequence data suggests that three Carteria species, C. lunzensis, C. crucifera, and C. olivieri, form a monophyletic group that is the basal sister group to all other ingroup flagellate taxa (including species of Chlamydomonas, Haematococcus, Stephanosphaera, Volvox, and Eudorina). Two other Carteria taxa, C. radiosa and Carteria sp. (UTEX isolate LB 762), form a clade that is the sister group to a clade that includes Haematococcus spp., Chlamydomonas spp., and Stephanosphaera. Thus, the sequence data support the interpretations of ultrastructural evidence that described two distinct Carteria lineages. Moreover, the sequence data suggest that these two Carteria groups do not form a monophyletic assemblage. Parsimony analysis of a suite of organismal (morphological, ultra‐structural, life history, and biochemical) character data also suggest two distinct lineages among the five Carteria taxa; however, the organismal data are ambiguous regarding monophyly of these Carteria taxa. When the two independent data sets are pooled, monophyly of Carteria is not supported; therefore, the weight of available evidence, both molecular and organismal, fails to support the concept of Carteria as a natural genus.
ALEXANDRIUM SATOANUM SP. NOV. (DINOPHYCEAE) FROM MATOYA BAY, CENTRAL JAPAN1
Authors: Yuki Katsuhisa , Fukuyo Yasuwo 
Published: October 2004

ABSTRACTThe gonyaulacoid dinofiagellate Alexandrium satoanum Yuki et Fukuyo sp. nov. is described from Matoya Bay, Pacific coast of central Japan. The species is distinctive in its conical epitheca with almost straight sides and dorsal concavity of the hypotheca. The plate formula is Po, pc, 4′, 6″, 6c, 10s, 5″″, and 2″″, including two accessory plates inside the sulcus. The apical pore plate is triangular and possesses an anterior attachment pore at the right margin. The first apical plate does not make contact with the apical pore plate and lacks a ventral pore. A posterior attachment pore lies at the center of the posterior sulcal plate. In Matoya Bay, vegetative cells occur as solitary cells or sometimes in pairs during late spring and early summer in low concentrations. In connection with this study, the following new combination is proposed: Alexandrium pseudogonyaulax (Biecheler) Horiguchi ex Yuki et Fukuyo comb. nov.
TEMPERATURE RESPONSES OF DISJUNCT TEMPERATE BROWN ALGAE INDICATE LONG‐DISTANCE DISPERSAL OF MICROTHALLI ACROSS THE TROPICS1
Authors: Peters Akira F. , Breeman Anneke M. 
Published: October 2004

ABSTRACTWe examined the temperature tolerance of microscopic phases from geographically disjunct isolates of eight species or closely related, putatively conspecific taxa of temperate brown algae with disjunct distributions. Maximum within‐taxon differences were small and ranged from 1.6° to 4.3° C. Desmarestia aculeata and Sphaerotrichia divaricata, both with northern hemisphere amphioceanic distributions, showed little or no significant intraspecific variation between the mean upper survival limits (USL) of Atlantic and Pacific strains (δUSL ≤ 1.4°C), which would agree with a relatively recent separation of the respective populations. Among the plants with bipolar distributions, there was likewise very little difference (δUSL 0–1.1°C) between northern and southern hemisphere strains in Striaria attenuata and in the species pair Desmarestia viridis/D. willii. In Desmarestia ligulata, and in the species pairs Desmarestia firma/D. munda, Dictyosiphon foeniculaceus/D. hirsutus, and Scytothamnus australis/Scytothamnus sp., significant differences occurred, which indicate longer divergence times. δUSL in these cases ranged from 1.7° to 2.7°C, without overlap between strains from the northern and southern hemispheres. All species that passed the equator during cooler epochs had a USL of 26–27°C, at least in some geographical isolates. The NE Asian kelp Undaria pinnatifida, which passed the equator in recent times, had a USL of 29.6°C. We hypothesize that the mechanism of spreading in the amphipolar species studied was migration of vegetative microthalli. The more unlikely alternative hypothesis of continuous populations through the tropics during a cooler epoch would imply a drop in seawater temperatures to approximately 20° C in summer and 15° C in winter, which is not supported by paleoclimatic evidence.
AN OUTBREAK OF DOMOIC ACID POISONING ATTRIBUTED TO THE PENNATE DIATOM PSEUDONITZSCHIA AUSTRALIS1
Authors: Fritz Lawrence , Quilliam Michael A. , Wright Jeffrey L. C. , Beale Allison M. , Work Thierry M. 
Published: October 2004

ABSTRACTA bloom of the pennate diatom Pseudonitzschia australis Frenguelli (= Nitzschia pseudoseriata Hasle) occurring in Monterey Bay, California, in early September 1991 coincided with an episode of mortality in brown pelicans (Pelicanus occidentalis) and Brandt's cormorants (Phalacrocorax penicillatus). High levels of domoic acid (DA), the amnesic shellfish poisoning toxin, were recorded in the plankton samples. Furthermore, high levels of DA, as well as numerous remnants of P. australis frustules, were found in the stomach contents of affected birds and in the visceral contents of local anchovies, a principal food source of seabirds. This is the first confirmed report of DA poisoning since the original 1987 episode in Atlantic Canada caused by Nitzschia pungens Grunow forma multiseries Hasle. It suggests another species of planktonic pennate diatom is capable of producing DA and that herbivorous finfish can act as vectors for this toxin.
DEGRADATION OF THE CELL‐WALL POLYSACCHARIDE OF PORPHYRIDIUM SP. (RHODOPHYTA) BY MEANS OF ENZYMATIC ACTIVITY OF ITS PREDATOR, GYMNODINIUM SP. (PYRROPHYTA)1
Authors: Simon Bracha , Geresh Shimona , Arad Shoshana (Malis) 
Published: October 2004

ABSTRACTThe dinoflagellate Gymnodinium sp., which preys specifically on cells of the red microalga Porphyridium sp., possesses enzymes that degrade exocellular polysaccharides of the Porphyridium sp. A crude extract of Gymnodinium sp. was applied to this polysaccharide, and the degradation products were characterized by charge and size separations. Charge separation revealed the presence of a fraction that was not found in the native polysaccharide. This fraction, which was eluted from an anion‐exchange resin with water alone, was composed mostly of glucose and xylose (in a 1:1 weight ratio). Size separation of the degradation products revealed three fractions; the molecular weight of the main one was 5 × 106 daltons, whereas that of the native polysaccharide was 7 × 106 daltons. The carbohydrate composition of these fractions was determined. Although the main product of degradation had a relatively high molecular weight, its viscosity was significantly reduced relative to the native polysaccharide. Additional enzymatic degradation is required for further exploration of the structure of the exocellular polymer of Porphyridium sp.
PIGMENT TURNOVER IN THE MARINE DIATOM THALASSIOSIRA WEISSFLOGII. II. THE 14CO2‐LABELING KINETICS OF CAROTENOIDS1
Authors: Goericke Ralf , Welschmeyer Nicholas A. 
Published: October 2004

ABSTRACTThe biosynthesis and turnover of the pigments fucoxanthin, diadinoxanthin (DD), and diatoxanthin (DT) were studied in exponentially growing cultures of the diatom Thalassiosira weissflogii (Grunow) Fryxell and Hasle to investigate the dependence of pigment turnover on algal growth rates and light intensity. 14C‐bicarbonate was used as a tracer. The labeling kinetics of fucoxanthin and DT were described satisfactorily by a simple precursor‐pigment model with two free parameters, the precursor and pigment turnover rate. At growth irradiances < 200 μE · m−2· s−1, labeling kinetics of DD indicated the presence of two kinetically distinct DD pools and at least one precursor pool. The average growth rate‐normalized pigment turnover rate of fucoxanthin was 0. The growth rate‐normalized turnover rate of DT, determined only at high light irradiances (> 200 μE·m−2·s−1), was 1.3. At high light irradiances, the growth rate‐normalized turnover rate of DD was 1.8. At low light irradiances, the turnover rates of the two DD pools were 3.7 and 0, respectively. The corresponding pigment turnover times were on the order of days to weeks, depending on the growth rate of the cultures. A comparison of pigment pool sizes, pigment turnover rates, and precursor turnover rates suggests that fucoxanthin is synthesized from a pool of DD and that DD and DT are synthesized from a common precursor, possibly β‐carotene. No evidence was seen for dynamic xanthophyll cycling. This suggests that the commonly known “xanthophyll cycle” is the simple unidirectional conversion of DD into DT, or of DT into DD, in response to rapid irradiance changes.
A PERSISTENT VIRUS INFECTION IN FELDMANNIA (PHAEOPHYCEAE)1
Authors: Henry Eric C. , Meints Russel H. 
Published: October 2004

ABSTRACTA virus infection is described within the unilocular sporangia of Feldmannia sp., a filamentous brown alga (Phaeophyceae). The alga is easily maintained in culture and vegetative growth is vigorous, but formation of icosahedral virions 150 nm in diameter completely displaces production of zoospores. The viruses, estimated at 1–5 × 106 per sporangium, are eventually released by rupture of the sporangial wall. Deoxyribonucleic acid (DNA) isolated from the viruses can be readily digested with restriction endonucleases and consists of ca. 170 kbp of double‐stranded DNA.
MICROTUBULE‐MICROFILAMENT‐CONTROLLED NUCLEAR MIGRATION IN THE DESMIDEUASTRUM OBLONGUM1
Authors: Url Thomas , Höftberger Margit , Meindl Ursula 
Published: October 2004

ABSTRACTPostmitotic nuclear migration inEuastrum oblongnumRalfs ex Ralfs starts about 80 min after septum formation with the nucleus leaving its central position in the isthmus and moving into the growing semicell. Nuclear migration is influenced by the chloroplast, which expands into the growing half‐cell and pushes the nucleus toward one side of the cell. The nucleus occupies its farthest position from the isthmus when located in the middle of the growing semicell directly under the central depression of the cell surface. It remains in this position during the subsequent stages of cell development and moves back toward the isthmus within a chloroplast groove about 12 h after completion of cell shape formation.Bundles of microtubules (MTs) emanating from a microtubule center surround the nucleus during its motion. They reach far into the growing half‐cell as long as the nucleus is moving but vanish when the nucleus stays in the growing semicell. MT‐disrupting agents inhibit the backward movement of the nucleus toward the isthmus indicating that MTs are involved in this motion too. Because both MT inhibitors and cytochalasin B influence nuclear motion inEuastrum, an interaction of MTs and microfilaments is thought to function as the motive force for nuclear migration.
THE MARINE DINOFLAGELLATE ALEXANDRIUM OSTENFELDII: PARALYTIC SHELLFISH TOXIN CONCENTRATION, COMPOSITION, AND TOXICITY TO A TINTINNID CILIATE1
Authors: Hansen Per Juel , Cembella Allan D. , Moestrup Øjvind 
Published: October 2004

ABSTRACTThe composition of paralytic shellfish toxins in the marine dinoflagellate Alexandrium ostenfeldii (Paulsen) Balech et Tangen grown in unialgal culture was determined by high‐performance liquid chromatography. The toxin profile revealed that the low‐potency sulfamate toxin B2 was dominant (90 molar % of total toxins), but small amounts of the weakly toxic 21‐N‐sulfocarbamoyl derivatives C1+2 and trace amounts of the carbamate toxins GTX2 and GTX3 were also present. The mammalian toxicity was confirmed by a modification of the conventional AOAC mouse bioassay (0.6–1.4 pg STXeq· cell‐1). The acute toxicity to a potential predator, the tintinnid ciliate Favella ehrenbergi (Clap, et Lach.) Jörg., was also investigated. The ciliate was able to graze on A. ostenfeldii when the cell concentration of the dinoflagellate was low (<2000 cells · mL‐1). At higher concentrations the ciliate was affected by exudates (presumably PSP toxins) that induced backward swimming followed by swelling and lysis of the cell. Fluorescence microscopy of calcofluor‐stained cells was employed as an easy and rapid method to identify this and other thecate dinoflagellates.
ANALYSIS OF GAMETIC PROTOPLAST RELEASE IN THE CLOSTERIUM PERACEROSUM‐STRIGOSUM‐LITTORALE COMPLEX (CHLOROPHYTA)1
Authors: Sekimoto Hiroyuki , Fujii Tadashi 
Published: October 2004

ABSTRACTA biologically active glycoprotein (protoplast‐release‐inducing protein; PR‐IP), which induces the release of gametic protoplasts from mating type minus (mt‐) cells of the Closterium peracerosum‐strigosum‐littorale complex, was prepared from a medium in which mt‐ and mt+ cells had been previously incubated together. The process of PR‐IP‐inducing protoplast release was analyzed. Induction of protoplast release was dependent upon the duration of both PR‐IP treatment and preincubation in nitrogen‐deficient mating medium before PR‐IP treatment. Low cell density in the preculture stage had a significant stimulative effect upon the induction of protoplast release. Light was necessary for protoplast release, especially just before PR‐IP treatment. Chloramphenicol and 3‐(4‐chlorophenyl)‐1,1‐dimethylurea (CMU) exerted inhibitory effects on protoplast release, especially when they were applied to the preculture stage but not when they were applied to the protoplast‐releasing stage after the PR‐IP treatment. We suggest that preculture at a low cell density under continuous light conditions that may cause metabolic changes in the chloroplast is a very important stage for gametic protoplast release in this Closterium.
THE EFFECT OF SODIUM CHLORIDE ON CARBONIC ANHYDRASE ACTIVITY IN MARINE MICROALGAE1
Authors: Dionisio‐Sese Maribel L. , Miyachi Shigetoh 
Published: October 2004

ABSTRACTThe effects of NaCl on the internal and external carbonic anhydrase (CA) activity of several marine microalgae were studied. Unlike freshwater microalgae in which CA activity is generally inhibited by NaCl, marine microalgae exhibited considerable species‐dependent variation when exposed to NaCl. CA activity in Phaeodactylum tricornutum, a diatom, was inhibited, whereas it was activated in the coccolithophorid Pleurochrysis carterae. CA activity in the chlorophyte Dunaliella primolecta was not significantly affected by NaCl. In Dunaliella salina and Dunaliella parva, NaCl inhibited external CA without affecting the internal activity, whereas in Chlorella vulgaris C‐133 and Dunaliella peircei only the internal CA was inhibited. Internal CA of Dunaliella tertiolecta was not affected by NaCl, but the external enzyme was significantly enhanced. Salt substitution experiments revealed that chloride (Cl‐) is the ion affecting CA activity; the effect of Cl‐ can be replaced by bromide ion. Cl‐ affects external CA activity while also affecting the apparent affinity for inorganic carbon during photosynthesis. Microalgae whose internal CA activity was enhanced by Cl‐ showed higher intracellular Cl‐ concentrations than those species that were inhibited.