bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF VARIATION IN TEMPERATURE. II. ON THE FATTY ACID COMPOSITION OF EIGHT SPECIES OF MARINE PHYTOPLANKTON1
Authors: Thompson Peter A. , Guo Ming‐xin , Harrison Paul J. , Whyte John N. C. 
Published: October 2004

ABSTRACTEight species of marine phytoplankton showed significant variation in the relative amount of some fatty acids (FAs) in response to variation in temperature. Large changes in relative amounts of certain FAs occurred as a result of a 15° C change in growth temperature. For example, 14:0 increased from ≃4% of total FAs at 10° C to > 20% at 25° C for Chaetoceros simplex and Isochrysis aff. galbana but decreased for Phaeodactylum tricornutum. The percentage of the polyunsaturated fatty acid (PUFA) 16:ω1 was consistently greater at 10° C than at 25° C, and the converse was usually true for 16: 4ω3. Calculated over all eight species, there was a modest but significant inverse relationship between the percentage of PUFAs and temperature. Only for Thalassiosira pseudonana was the percentage of either of the PUFAs and nutritionally essential fatty acids (EFAs) also an inverse function of temperature. For T. pseudonana, the percentage of the EFA 22:6ω3 decreased linearly with increasing temperature over the range from 10 to 25° C.For three species, the ratio of unsaturated/saturated FAs was correlated with growth rate when growth rate was controlled by variation in irradiance and temperature. Only for Thalassiosira pseudonana was the ratio of unsaturated/saturated FAs also an inverse function of temperature alone.
PIGMENT TURNOVER IN THE MARINE DIATOM THALASSIOSIRA WEISSFLOGII. I. THE 14CO2‐LABELING KINETICS OF CHLOROPHYLL a1
Authors: Goericke Ralf , Welschmeyer Nicholas A. 
Published: October 2004

ABSTRACTThe turnover of chlorophyll a (chl a) was investigated in the diatom Thalassiosira weissflogii (Grunow) Fryxell and Hasle using a new method based on the incorporation of 14C into chl a. The alga was maintained in its exponential growth phase under continuous light; 14C was supplied as bicarbonate. The time course of label accumulation into the tetrapyrrole ring and the phytol side chain was determined for time periods equivalent to 1–2 cell doublings. The labeling kinetics of the tetrapyrrole ring and the phytol side chain were described satisfactorily by a simple precursor‐pigment model with two free parameters, the precursor turnover rate and the pigment turnover rate, both having dimensions of time−1. The model was fit to the experimental data to determine the values of these two free parameters. The turnover rates of the tetrapyrrole ring and the phytol side chain were not significantly different, ranging from 0.01 to 0.1 per day. These rates are equivalent to turnover times ranging from days to weeks. Growth rate‐normalized turnover rates did not vary with irradiance (7.5–825 μE · m−2· s−1). The precursor turnover rates of the tetrapyrrole ring and the phytol side chain differed by an order of magnitude. These results indicate that chl a is not degraded significantly in cultures of T. weissflogii grown under continuous light. Neither irradiance nor growth rate affected growth rate‐normalized chlorophyll turnover rates. Our results are inconsistent with the hypothesis that steady‐state cellular concentrations of chl a are maintained by a dynamic equilibrium between rates of synthesis and degradation.
NUCLEOTIDE SEQUENCES OF THE SMALL‐SUBUNIT RIBOSOMAL RNA GENES FROM SELECTED LAMINARIALES (PHAEOPHYTA): IMPLICATIONS FOR KELP EVOLUTION1
Authors: Saunders Gary W. , Druehl Louis D. 
Published: October 2004

ABSTRACTThe entire small‐subunit (SSU) ribosomal ribonucleic acid sequence was inferred for kelp representing seven genera: Alaria marginata Postels and Ruprecht (1824 bp), Egregia menziesii (Turner) Areschoug (1825 bp), Lessoniopsis littoralis (Tilden) Reinke (1825 bp), Macrocystis integrifolia Bory (1825 bp), Nereocystis leutkeana (Mertens) Postels and Ruprecht (1824 bp), Postelsia palmaeformis Ruprecht (1826 bp), and Pterygophora californica Ruprecht (1825 bp). We obtained a partial sequence for Eisenia arborea Areschoug (1669 bp) from a single clone of polymerase chain reaction‐amplified product. The SSU sequence was too conserved among these morphologically distinct taxa to permit phylogenetic analysis. The divergence between the most distant taxa was only 0.66%. This value was used in a SSU molecular clock to suggest that the most distantly related kelp investigated in this study diverged between 16 and 30 (more probably 16 and 20) million years ago.
CONFIRMATION OF DOMOIC ACID PRODUCTION BY PSEUDONITZSCHIA AUSTRALIS (BACILLARIOPHYCEAE) CULTURES1
Authors: Garrison David L. , Conrad Steve M. , Eilers Paul P. , Waldron Ellen M. 
Published: October 2004

ABSTRACTSingle done isolates of Pseudonitzschia australis Frenguelli (= Nitzschia pseudoseriata Hasle) isolated from a toxic bloom in Monterey Bay, California produced domoic acid in culture. Although long‐term historical records do not indicate previous blooms of this species on the Pacific coast, this is probably because it has been often misidentified as Nitzschia seriata Hasle; previous evidence for toxicity is lacking. Hydrographic data suggest that areas such as Monterey Bay might be “hot spots” for domoic acid‐producing blooms.
AUXOSPORULATION IN CYCLOTELLA OCELLATA (BACILLARIOPHYCEAE) UNDER NATURAL AND EXPERIMENTAL CONDITIONS1
Authors: Pérez‐Martínez Carmen , Cruz‐Pizarro Luis , Sánchez‐Castillo Pedro 
Published: October 2004

ABSTRACTGrowth and sexual reproduction in a population of Cyclotella ocellata Pantocseck were studied during one annual cycle in a reservoir and in short‐term enclosure experiments performed in situ involving different nutrient conditions and concentrations of zooplankton species. Three phases of auxosporulation in this diatom were distinguishable morphologically: 1) preauxospore, from the beginning of zygote formation until the valves were longitudinally separated, 2) primary auxospore, when the zygote grew too large to fit inside the valves and before it reached its full size, and 3) mature auxospore, characterized by a well‐developed, markedly scalloped edge. Under experimental and natural conditions, sexual reproduction was associated with changes in cell size. In the natural system, the auxospore appeared to act as a resting structure during conditions adverse for population growth. A threshold population of small cells appeared to be necessary for sexual reproduction in the natural system, whereas auxosporulation was associated with phosphorus fertilization in the enclosures. In both environments only cells smaller than 9.5 μm in diameter were capable of auxospore formation. Our results suggest that, once having reached the critical cell size, the factors that trigger sexual reproduction may depend on ambient environmental conditions.
GROWTH AND PHOTOSYNTHESIS OF ULVA ROTUNDATA (CHLOROPHYTA) AS A FUNCTION OF TEMPERATURE AND SQUARE WAVE IRRADIANCE IN INDOOR CULTURE1
Authors: Henley William J. 
Published: October 2004

ABSTRACTTemperature and photon flux density (PFD) vary independently in estuaries, e.g. high PFD may occur at any temperature, so it is necessary to consider synergistic effects of these factors on algal growth. Because natural PFD is highly variable and daylength changes confound seasonal temperature cycles, it is easier to interpret factorial experiments in controlled laboratory conditions. Clonal Ulva rotundata Blid. (Chlorophyta) has been studied extensively in outdoor culture. In this study it was maintained indoors under square wave photoperiods at five PFDs and three temperatures. Growth rate, photqsynthetic light response (P‐I) curves, and photosystem II chlorophyll fluorescence properties were measured at the growth temperature following acclimation. Interactions between PFD and growth temperature were strongly indicated in all physiological parameters measured. Greatest PFD response occurred at the highest temperature, and the largest temperature response occurred at the highest PFD. Light‐saturated photosynthesis (Pm) dark respiration (Rd), and light‐limited quantum yield (Φm) were sufficient to describe acclimation status. The light‐saturation parameter (Ik) was redundant and potentially misleading. Although U. rotundata exhibits a great amplitude of photoacclimation, it apparently has little capacity for temperature acclimation compared to the kelp, Laminaria saccharina, for which published data indicate similar photosynthetic rates over a broad range of growth temperatures. Diurnal variation of Pm and Rd at a growth PFD of ∼ 1700 ± 200 μmol photons · m−2· s−1 was similar to the pattern observed previously in outdoor culture, suggesting endogenous control of these parameters. Quantum yield and the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm), which were depressed in midday sunlight exceeding ∼ 1500 μmol photons · m−2· s−1, were relatively invariant through the day in indoor culture, indicating that these parameters are controlled primarily by instantaneous PFD. Growth and fluorescence data are also presented for some other macroalgae for comparative purposes.
ULTRASTRUCTURE OF VEGETATIVE ORGANIZATION AND CELL DIVISION IN THE UNICELLULAR RED ALGADIXONIELLA GRISEAGEN. NOV. (RHODOPHYTA) AND A CONSIDERATION OF THE GENUSRHODELLA1
Authors: Scott Joseph L. , Broadwater Sharon T. , Saunders Bill D. , Thomas Jewel P. , Gabrielson Paul W. 
Published: October 2004

ABSTRACTThis study suggests that the genusRhodellabe restricted to that set of features currently observed only inRhodella maculataEvans andRhodella violacea(Korn‐mann) Wehrmeyer, that a new genusDixoniellabe established to accommodate the unicellular red alga,Rhodella grisea(Geitler) Fresnel, Billard, Hindák et Pekár‐ková, and thatRhodella cyaneaBillard et Fresnel be further studied for probable reclassification. These conclusions are based on ultrastructural comparisons ofDixoniella griseawith published information on the genusRhodella.The presence of thylakoids in the pyrenoid, a peripheral encircling thylakoid in the chloroplast, a dictyosome/nuclear envelope association, and the lack of a specialized pyrenoid/nucleus association inD. griseaseparate this alga from the genusRhodella.Cell division inD. griseais not demonstrably different from that inRhodella, although the unusually well‐defined material of the presumptive microtubule organizing center (MTOC) made it possible to follow the development and behavior of the MTOC to a greater degree than in previously studied red algal cells. The surprising amount of conformity in cell division characters betweenD. griseaand the genusRhodellaprompted a comparison of cell division characteristics in all red algal unicells studied to date.All unicells show a remarkable degree of similarity except for differences in interzonal spindle length, dissimilarities in size of the nucleus‐associated organelle (NAO), and the unusual NAO ofPorphyridium purpureum(Bory) Drew et Ross.
BIOGEOGRAPHY OF CLADOPHOROPSIS MEMBRANACEA (CHLOROPHYTA) BASED ON COMPARISONS OF NUCLEAR rDNA ITS SEQUENCES1
Authors: Kooistra Wiebe H. C. F. , Stam Wytze T. , Olsen Jeanine L. , van den Hoek Chris 
Published: October 2004

ABSTRACTNucleotides were compared at 988 sites, spanning both internal transcribed spacers (ITS1 and ITS2) of the nuclear ribosomal DNA, among 17 isolates of the green alga Cladophoropsis membranacea (Hofman Bang ex C. Agardh) Boergesen and two isolates of Struvea anastomosans (Harvey) Piccone and Grunow. Collections were made from Bonaire, Curaçao, St. Croix, the Canary Islands, the Cape Verde Islands, Mauritania, Syria, the Red Sea, Okinawa, and Hawaii. Two nucleotide substitutions were found between the sequenced coding regions of C. membranacea and S. anastomosans. Of the 720 nucleotides compared in ITS1 and ITS2, an average of 6.7% sequence divergence was found within C. membranacea and 17.4% between C. membranacea and S. anastomosans. Sequences were analyzed using maximum parsimony. Phylogenetic hypotheses were compared with the biogeographic hypothesis of an east‐west Tethyan vicariance. Results of the study allow the identification of widely dispersed biogeographic populations, the identification of an underlying Tethyan imprint, and support for the hypothesis that dispersal has occurred between the Caribbean and the tropical eastern Atlantic. These results demonstrate the usefulness of ITS sequences at the sub‐specific level in C. membranacea.
CULTURE STUDIES ON THE LIFE HISTORY OF CHORDARIA LINEARIS (PHAEOPHYCEAE) FROM TIERRA DEL FUEGO, SOUTH AMERICA1
Authors: Peters Akira F. 
Published: October 2004

ABSTRACTStudies of laboratory cultures of Chordaria linearis (Hooker et Harvey) Cotton from southernmost South America revealed that this species has an obligate sexual life history in which a macroscopic sporophyte alternates with a monoecious microscopic gametophyte. Sexual reproduction is isogamous and under photoperiodic control. Gametes are produced only in short days, whereas in long days, asexual zoospores are formed that recycle the gametophyte generation. Unfused gametes develop into gametophytes, and sporophytes originate only from zygotes. Unlike other sexual members of the Chordariales, gametes of C. linearis have a reduced stigma and do not show phototaxis. They are released at the beginning of the night, not in the morning. In nature, C. linearis seems to be regularly infected by a dictyosiphonalean epiphyte resembling the rare arctic species Trachynema groenlandicum (Lund) Pedersen. The epiphyte is responsible for previous contradictory results obtained in laboratory cultures of C. linearis. This is the first record of Trachynema in the southern hemisphere.
LYNGBYAINFESTATIONS: COMPARATIVE TAXONOMY OFLYNGBYA WOLLEICOMB. NOV. (CYANOBACTERIA)1
Authors: Speziale Barbara J. , Dyck Lawrence A. 
Published: October 2004

ABSTRACTConflicting taxonomic identifications of an extremely large‐celled (width: 24.9–64.4 μm, length: 2.0–11.5 μm), filamentous, mat‐forming cyanobacterium prompted a search for an accurate taxonomic identity. This alga was reported by various workers asPlectonema wolleiFar‐low ex Gomont,Lyngbya majusculaHarvey ex Gomont,Lyngbya magnificaGardner,Lyngbya birgeiSmith,Lyngbya latissimaPrescott, andMicrocoleus lyngbyaceus (Kützing)Crouan sensu Drouet. Quantitative analyses of cellular morphology, evaluation of habitat preference, and growth form were used to characterize the organism. Descriptions and taxonomic histories of this organism and the six described taxa were compared.The organism is identified asPlectonema wolleiFar‐low ex Gomont according to most existing botanical taxonomic systems. However, this identification places undue emphasis on the extremely variable characteristic of false branching, which varies seasonally and with growth status. To eliminate the confusion inherent in basing taxonomy upon an environmentally variable characteristic, identification asLyngbya wollei(Farlow ex Gomont) comb. nov. is recommended.
CHRONIC EFFECTS OF ULTRAVIOLET‐B RADIATION ON GROWTH AND CELL VOLUME OF PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1
Authors: Behrenfeld Michael J. , Hardy John T. , Lee Henry 
Published: October 2004

ABSTRACTCultures of the temperate estuarine diatom, Phaeodactylum tricornutum Bohlin (NEPCC Clone 31), were grown under ambient intensities of ultraviolet‐A radiation (UVAR), photosynthetically active radiation (PAR), and various intensities of ultraviolet‐B radiation (UVBR; 290–320 nm). Growth rates and cell volumes were monitored for 36 d. UVBR decreased growth rates and increased cell volumes. Sensitivity of growth to UVBR increased with time. Growth rates of P. tricornutum decreased with increasing ratios of UVBR:UVAR + PAR.
EFFECTS OF DESICCATION AND ILLUMINATION ON PHOTOSYNTHESIS AND PIGMENTATION OF AN EDAPHIC POPULATION OF TRENTEPOHLIA ODORATA (CHLOROPHYTA)1
Authors: Ong Bee‐Lian , Lim Melin , Wee Yeow‐Chin 
Published: October 2004

ABSTRACTThe photosynthetic rates of Trentepohlia odorata (L.) Martius growing on wall surfaces in Singapore changed throughout the day with a maximum in midmorning and decreasing thereafter during the day. Optimum temperature for photosynthesis was 25° C. Different levels of air humidity also affected photosynthetic rates with low relative humidity reducing the rates and efficiency of photosynthesis. Our results suggested that T. odorata was able to maximize its rate of photosynthesis before photoinhibitory light levels were reached and that its growth might be dependent on high levels of atmospheric relative humidity, which may serve as a source of water supply for the alga.
EFFECT OF NITROGEN STARVATION ON THE BIOCHEMISTRY OF PHORMIDIUM LAMINOSUM (CYANOPHYCEAE)1
Authors: Fresnedo Olatz , Serra Juan L. 
Published: October 2004

ABSTRACTCells of the non‐N2‐fixing cyanobacterium Phormidium laminosum (Agardh) Gomont (strain OH‐1‐pCl1) showed doubling times of 24 h in media containing nitrate and 120 h in media without a nitrogen source. Nitrogen starvation resulted in a drastic decrease in the cellular content of chlorophyll, phycobiliproteins (phycocyanin and allophycocyanin), and other soluble proteins, although the total protein of cells was unchanged. N‐starved cells showed an exocellular layer of mucilage that rapidly increased with starvation time. The appearance of N deficiency symptoms was strongly dependent on culture conditions, and it was faster under the optimal conditions used for cell growth. The relative content of C and N of nitrate‐grown cells remained more or less constant during all growth phases (C/N ratio of ca. 5) but diminished at different rates in N‐starved cells. Cells subjected to N starvation for 48 h had a C/N ratio of more than 10. N starvation also resulted in the selective degradation of soluble poly‐peptides of masses lower than 20 kDa (which include those constituting phycobiliproteins), whereas the relative content of soluble polypeptides of greater size increased.
THE CONTRACTILE VACUOLE AS AN ENDOCYTIC ORGANELLE OF THE CHLAMYDOMONAD FLAGELLATE GLOEOMONAS KUPFFERI (VOLVOCALES, CHLOROPHYTA)1
Authors: Domozych David S. , Nimmons Trevor T. 
Published: October 2004

ABSTRACTThe endomembrane system of the chlamydomonad flagellate, Gloeomonas kupfferi Skuja, consists of a complex network of endoplasmic reticulum, Golgi bodies, and various vacuoles. One of the more distinct vacuolar components is the contractile vacuole (CV) complex, which consists of two anterior contractile vacuoles that expand/contract approximately every 30 s. In this study, experimental cytochemical labeling was performed to help elucidate possible endocytic/membrane recycling mechanisms in Gloeomonas and the possible role of the contractile vacuole in this process. When incubated with 0.5 mg · mL−1 cationic ferritin for short periods of time (2–60 min), labeling follows this route: inner membrane of CV, globular deposits in the CV and associated vesicles, and ultimately the terminal trans face cisternae of the Golgi apparatus (GA). Similar incubations with Lucifer yellow and concanavalin A—gold conjugates support distinct uptake of exogenous ligands by the CV and associated vesicles. Our results suggest that the contractile vacuole may be a site of endocytosis and that the trans GA loci may be a key site of membrane recycling.
NUCLEAR RIBOSOMAL DNA INTERNAL TRANSCRIBED SPACER REGIONS (ITS1 AND ITS2) DEFINE DISCRETE BIOGEOGRAPHIC GROUPS IN CLADOPHORA ALBIDA (CHLOROPHYTA)1
Authors: Bakker Freek T. , Olsen Jeanine L. , Stam Wytze T. , van den Hoek Chris 
Published: October 2004

ABSTRACTNucleotide sequences of the nuclear ribosomal DNA internal transcribed spacers (ITS1 and ITS2), the 5.8S, and short stretches of the adjacent 18S and 26S coding regions were determined in isolates from four disjunct Cladophora albida (Huds.) Kütz. populations (NE‐America, W‐Europe, Japan, and W‐Australia). The two Pacific isolates share nearly identical ITS sequences as do the two Atlantic isolates. In contrast, interoceanic comparisons exhibit a 21% sequence difference. Variation within ITS regions is useful for identification of population groups on a regional or oceanic scale. However, both spacers are characterized by numerous repeat motifs as well as point mutations, which result in alignment problems at the interspecific level within Cladophora.
Altered glycosylation leads to Tr polyagglutination
Authors: Halverson G.R. , Lee A.H. , Øyen R. , Reiss R.F. , Hurlet‐Jensen A. , Reid M.E. 
Published: October 2004

BACKGROUND:  Polyagglutination refers to red blood cells (RBCs) that are agglutinated by a high proportion of ABO‐matched adult sera but not by cord sera. Polyagglutinable RBCs have been associated with microbial infection, myeloproliferative disorders, and myelodysplasia. Lectins aid in the identification of polyagglutination.CASE STUDY:  A Hispanic male infant with mild hemolytic anemia, a “Bernard‐Soulier‐like” syndrome, intermittent neutropenia, mitral valve regurgitation, ligament hyperlaxity, and mild mental retardation was studied. The patient's Group O RBCs were polyagglutinable; they were agglutinated by normal human sera, several lectins [including Arachis hypogea, Salvia sclarea, Salvia horminum, Glycine max, Ulex europaeus, Griffonia simplicifolia I, and Gr. simplicifolia II], and some monoclonal antibodies. His RBCs were not agglutinated by cord sera, Dolichos biflorus, or Phaseolus lunatus. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis on the RBC membranes followed by staining with periodic acid‐Schiff stain showed markedly reduced staining of glycophorins A and B. Staining with Coomassie brilliant blue revealed that Band 3 has a faster mobility than normal.CONCLUSIONS:  Collectively, the results suggest that the patient's RBCs have a reduction in N‐acetylneuraminic acid on both N‐ and O‐glycans, exposing, respectively, β1,4‐galactosidase and β1,3‐galactosidase. The patient likely has an altered glycosyltransferase that results in defective glycosylation in RBCs and other cell lineages. This type of polyagglutination was named Tr.