bluuebunny/crossref_metadata_2025_split huggingface dataset:
REGULATION OF ALTERNATIVE PATHWAY RESPIRATION IN CHLAMYDOMONAS REINHARDTH (CHLOROPHYCEAE)1
Authors: Weger Harold G. , Dasgupta Roshni 
Published: October 2004

ABSTRACTThe inhibitor propyl gallate was used to estimate partitioning of respiratory electron flow between the cytochrome amd alternative pathways in Chlamydomonas reinhardtii Dangeard. Nutrient limitation (nitrogen or phosphorus resulted in a large increase in alternative pathway capacity relative to cytochrome pathway activity, without regulating in engagement of the alternative pathway. High rates of respiration, which could be induced in phosphate‐starved cells by a combination of phosphate addition and uncoupler, resulted in alternative pathway activity. Osmotic stress resulted in decreased electron flow through the cytochrome pathway and increased flow through the alternative pathway, while high temperature also resulted in alternative pathway engagement. Incubation with exogenous carbon sources could increase the rate of respiratory O2 consumption; the increase was mediated entirely by the alternative pathway. We suggest that the alternative pathway functions in these cells both to maintain respiration during environmentally induced stress and as on energy overflow.
CARBONIC ANHYDRASE IN THE CHLOROPLAST OF A COCCOLITHOPHORID (PRYMNESIOPHYCEAE)1
Authors: Quiroga Olivia , González Elma L. 
Published: October 2004

ABSTRACTThe activity and subcellular distribution of carbonic anhydrase in a coccolithophorid alga, CCMP 299, was examined. The enzyme could not be detected in crude cell homogenates but was present at high specific activity (27.5 unit·mg−1 protein) in chloroplasts (density, 1.14 g·cm−3) isolated in a sucrose gradient. The carbonic anhydrase activity was sensitive to known inhibitors. Inhibition at 50% (I50) was obtained with concentrations of 4.60 mM and 2.65 mM for acetazolamide and NaN3, respectively. These levels are more consistent with patterns of inhibition previously observed for chloroplastic (as compared to periplasmic) carbonic anhydrase. In this organism, carbonic anhydrase was localized in the chloroplast stroma. These findings are discussed in terms of the relationship among dissolved inorganic carbon interconversions, photosynthesis, and calcification.
NUCLEAR BASIC PROTEINS FROM THE BINUCLEATE DINOFLAGELLATE PERIDINIUM FOLIACEUM (PYRROPHYTA)1
Authors: Morris Rodney L. , Fuller Christopher B. , Rizzo Peter J. 
Published: October 2004

ABSTRACTHistories of the endosymbiont nucleus of the binucleate dinoflagellate Peridinium foliaceum Stein were prepared from isolated nuclei and analyzed by peptide mapping, ammo acid composition, and two‐dimensional gel electrophoresis. Using these criteria, we identified the presence of two HI‐like histories and the core histones H3, H2A, H2B, and H4. These histones are similar but not identical to those of the endosymbiont nucleus of the bi‐nucleate dinoflagellate Peridinium balticum Levander.
STRUCTURE AND COTRANSCRIPTION OF THE PLASTID‐ENCODED rbcL. AND rbcS GENES OF PLEUROCHRYSIS CARTERAE (PRYMNESIOPHYTA)1
Authors: Fujiwara Shoko , Iwahashi Hitoshi , Someya Junichiro , Nishikawa Satoshi , Minaka Nobuhiro 
Published: October 2004

ABSTRACTGenes for the large (rbcL) and small (rbcS) subunits of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) from the prymnesiophyte Pleurochrysis carterae (Braarud and Fagerl.) Christensen were isolated and characterized. The genes are located close to each other, separated by an intergenic region of 87 nucleotide base pairs. Southern and Northern blot analyses indicate that these genes are encoded by plastid DNA and cotranscribed, as in the Cryptophyta, Chromophyta, and Rhodophyta studied so far. The genes of Pleurochrysis show higher identities with those of the Cryptophyta, Chromophyta, Rhodophyta, and the α (Type I)‐ and β‐purple bacteria than with those of the Chlorophyta or Cyanophyta. The molecular Phylogenetic tree of rbcL genes suggests that the plastids of the Prymnesiophyta, Cryptophyta, and Chromophyta originated from those of the Rhodophyta, which agrees with the secondary endosymbiotic theory. Northern analysis of Pleurochrysis demonstrated that a certain amount of the transcript is possibly processed around the 3′ end rbcL. When cells were transferred from light to dark for 6 h, the amount of Rubisco messenger RNA (mRNA) was almost the same as in continuous light. This suggests that Rubisco mRNA is synthesized and/or stable even in the dark.
SURFACE MORPHOLOGY OF THE MARINE DINOFLAGELLATE SINOPHYSIS MICROCEPHALUS (DINOPHYCEAE) FROM A MANGROVE ISLAND. TWIN CAYS. BELIZE1
Authors: Faust Maria A. 
Published: October 2004

ABSTRACTSinophysis microcephalus Nie and Wang 1944 is a nonphotosynthetic, tropical, benthic. dinophysoid dinoflagellate. I isolated it from floating detritus on a subtropical mangrove island. Twin Cays. Beleze, Central America, and describe its micromorphology from light and scanning electron micrographs. Cells of S. microcephalus are circular to subcircular and compressed laterally with a cell size of 42‐44 μm long and 33–35 μm wide and with a length /width ratio of 1.25–1.28. Areolae are numerous, 368–550 per valve, ranging in size from 0.75 to 2.0 μm. Pores are oblong and deeper at the valve's center and pentagonal‐shaped at the plate margin. The well‐defined cingulum is narrow and deeply incised with a smooth surface. The epitheca is small, moderately convex, and divided into two large, highly ornate, asymmetrical plate: the left and right epitheca I plates. The left epithecal plate bears two slightly curved, upright anterior projections located dorsally adjacent to the epithecal list, a relatively large opening, and three smaller openings compressed against the sagittal suture. The right plate contains a wide megacytic zone with two parallel ridges, a fairly large oblong opical pore in ventral position adjacent to the cingulum, and eight areolae each with a round, uniform‐sized pore opening. There are two long and narrow sulcal lists, gently convex with a smooth edge without structure or ribs. The left sulcal list has an ear‐shaped labe, a form of a primitive dinophysoid list. The megacytic zone is smooth and expands unevenly during cell division. The epitheca and sulcus distinguishes S. microcephalus from all examined Dinophysis.
GENOTYPIC VARIATION AND ALTERNATING DNA LEVELS AT CONSTANT CHROMOSOME NUMBERS IN THE LIFE HISTORY OF THE BROWN ALGA HAPLOSPORA GLOBOSA (TILOPTERIDALES)1
Authors: Kuhlenkamp Ralph , Müller Dieter G. , Whittick Alan 
Published: October 2004

ABSTRACTThe brown algal order Tilopteridales contains three monospecific genera with reduced life histories, Which are assumed to have been derived form ancestors with oogamous reproduction and alternation of generations. The Newfoundland population of Haplospora globosa Kjellman still shows an alternation of gametophytes and sporophytes, but the chromosome Numbers remain equal because of parthenogenesis and apomeiosis, However, DNA fluorometry showed that the DNA level is twice as high in the Sporophytes as in the gametophytes, The DNA variation at constant chromosome numbers is presumably due to endomitosis combined with a law degree of polyteny. A genotypic variant of Haplospora is represented by the population at Helgoland (F.R.G.) where only sporophytes exist, Spores develop into sporophytes instead of gametophytes, and the plants have reduced chromosome number but the same DNA level as the Newfoundland sporophytes
PCR AMPLIFICATION OF NUCLEAR AND PLASTID GENES FROM ALGAL HERBARIUM SPECIMENS AND ALGAL SPORES1
Authors: Goff Lynda J. , Moon Debra A. 
Published: October 2004

ABSTRACTPlastid and nuclear ribosomal genes were amplified from an 11‐year‐old herbarium specimen using simple, rapid, nontoxic, and inexpensive methods. Gonimoblast tissue, isolated from either dried or fresh red algal cystocarps, was ground using the polyvalent, metal chelating resin Chelax 100. After boiling and centrifuging, the supernatant yielding enough DNA for 20 or more polymerase chain reactions. Using these methods, we also amplified plastid and nuclear genes from as few as two red algal spores. These methods should facilitate future studies of algal systematics, evolutionary biogeography, and phylogeny as well as studies of algal dispersal patterns and population biology.
COCCOLITH PRODUCTION AND DETACHMENT BY EMILIANIA HUXLEYI (PRYMNESIOPHYCEAE)1
Authors: Balch William M. , Kilpatrick Katherine , Holligan Patrick M. , Cucci Terry 
Published: October 2004

ABSTRACTLaboratory experiments were performed with the prymnesiophyte Emiliania huxleyi (Lohm.) Hay and Mohler, strain 88E, to quantify calcification per cell, coccolith detachment, and effects of coccolith production on optical scattering of individual cells. 14C incorporation into attached and detached coccoliths was measured using a bulk filtration technique. 14C‐labeled cells also were sorted using a flow cytometer and analyzed for carbon incorporation into attached coccoliths. The difference between the bulk and flow cytometer analyses provided a 14C‐based estimate of the rate of production of detached coccoliths. Coccolith production and detachment were separated in time in batch cultures, with most detachment happening well after calcification had stopped. Accumulation of coccoliths was maximum at the end of logarithmic growth with 50–80 coccoliths per cell (three to five complete layers of coccoliths around the cells). Net accretion rates of coccoliths were on the order of 7 coccoliths· cell−1·d−1 while net detachment rates were as high as 15 coccoliths· cell−1·d−1 for stationary phase cells. Equal numbers of coccoliths were attached and detached early in logarithmic growth, and as cells aged, the numbers of detached coccoliths exceeded the attached ones by a factor of 6. Our results demonstrate pronounced charges of forward angle light scatter and 90° light scatter of cells as they grow logarithmically and enter stationary phase. Counts of loose coccoliths in batch cultures are consistent with the detachment of coccoliths in layers rather than individual coccoliths.
DIATOM ASSEMBLAGES AS INDICATORS OF LAKE TROPHIC STATUS IN SOUTHEASTERN ONTARIO LAKES1
Authors: Christie Catherine E. , Smol John P. 
Published: October 2004

ABSTRACTCanonical correspondence analysis (CCA) was used to explore the relationship between measured environmental variables and surficial diatom (Bacillariophyceae) assemblages in alkaline lakes from southeastern Ontario. Total nitrogen (TN), watershed area, alkalinity, and maximum depth each explain significant (P ≤ 0.05) directions of variance in the distribution of diatom taxa.TN was highly correlated to total phosphorus (TP) (r = 0.92), chlorophylla(r = 0.86), and Secchi depth (r =0.77). When a series of CCAs were run with the first axis constrained to each of these variables in turn, the ratio of the eigenvalue of the first axis to that of the second axis (λ1/λ2) was highest for TN, indicating that TN best explained the distribution of the diatom assemblages in this set of lakes. Furthermore, results of Monte Carlo permutation tests indicated that these four variables did not act independently on the diatom assemblages. Therefore, TN was selected to represent these four closely related variables to infer lake trophic status.Weighted‐averaging regression and calibration (with classical deshrinking) were used to develop transfer functions to infer TN from the relative abundances of 83 diatom taxa recovered from the surficial sediments of 51 lakes. There was a good correlation between diatom‐inferred TN concentrations and measured TN concentrations (r2= 0.75, n = 51).The weighted‐averaging regression and calibration model was used to infer lake trophic status (represented by TN) from diatom assemblages presented in the sediments from Little Round Lake, Ontario. These data were used in conjunction with historical land‐use data in order to quantify the sequence and extent of nutrient enrichment related to human activity in the watershed area.
A SEARCH FOR SOME ANG1OSPERM HORMONES AND THEIR METABOLITES IN CAULERPA PASPALOIDES (CHLOROPHYTA)1
Authors: Jacobs William P. 
Published: October 2004

ABSTRACTThe best available methods were used to search for an‐giosperm hormones in the green alga Caulerpa paspa‐loides (Bory) Greville. Solvent partitioning of methanol extracts led to acidic ethyl acetate fractions that it were run through high‐performance liquid chromatography. Each of the resulting 25 fractions was divided in half so that one half was tested in the dwarf rice or lettuce hypocotyl assays for gibberellins and the other half was methylated and silylated for capillary gas chromatography combined with computerized mass spectrometry. By comparing algal mass spectra with spectra in the extensive library of mass spectra and associated Kovats Retention Indices that MacMillan's Bristol group has amassed, indole‐3‐acetic acid's presence in the alga was confirmed and dioxindole‐3‐acetic acid was found. However, despite the presence of several peaks of gibberellin‐like activity in the bioassays, no gibberellin or gibberellin metabolite was found in the thousands of full mass spectra examined. The gibberellin‐like activity in the acidic ethyl acetate fractions was therefore presumably not from any gibberellin known from vascular plants.
AUTO‐, HETERO‐, AND MIXOTROPHIC GROWTH OF CHLAMYDOMONAS HUMICOLA (CMLOROIMIYCKAK) ON ACETATE1
Authors: Lalibertè Gilles , de la Noüie Joël 
Published: October 2004

ABSTRACTRelative growth rate, isocitrate lyase activity, chlorophyll, protein, lipid, and soluble carbohydrate contents were investigated in Chlamydomonas humicola Lucksch during auto‐, mixo‐, and heterotrnphic growth. Mixotrophic cells have a relative growth rate of 1.66 d –1as compared to 0.78 d –1 and 0.21 d –1 for hetero‐ and autotrophic cells, respectively. Addition of acetate to autotrophic cells resulted in an increase in cell dry weight during the first day, followed by a rapid decrease and stabilization at 40 pg·cell –1. Cellular yield of mixotrophu cells, on a dry weight basis, was 6.6 times that of heterotrophic cells and 21.9 limes that of autotrophic ones. After 4 d, mixotrophic cells were characterized by higher chlorophyll (3.6% dry weight [d.w.]) and protein (58.6% d.w.) contents and lower lipid (4.8% d.w.) and soluble carbohydrate (1.3% d.w.) contents than those of autotrophic (2.6% d.w. chlorophyll, 31.0% d.w. protein, 10.2% d.w. lipid, and 6.5% d.w. soluble carbohydrate) and heterotrophic (1.5% d.w. chlorophyll, 36.9% d.w. protein, 5.6% d.w. lipid, and 6.0% d.w. soluble carbohydrate) cells. The ratio of chlorophyll a/b was highest in heterotrophic cells due to lower chlorophyll b content. Isocitrate lyase activity, a key enzyme in ecetate assimitation, could not be detected in autotrophic cells. Addition of 10 mM acetate to the culture medium of hetero‐ and mixotrophic cells resulted in increased isocitrate lyase activity with a maximum after 24 h, followed by a decline in activity over a 7‐d period. After 7 d of growth, only 0.01 mM acetate was found in the culture medium of mixotrophic cells as compared to 3.2 mM in the medium of heterotrophic ones, from an initial concentration of 10 mM.
ALTERATIONS IN LIPID MOLECULAR SPECIES OF THE MARINE EUSTIGMA TOPHYTE NANNOCHLOROSIS SP.1
Authors: Sukenik Assaf , Yamaguchi Yuji , Livne Alexander 
Published: October 2004

ABSTRACTThe molecular species of triacylglycerol and monogalactosyl diacylglycerol from the marine eustigmatophyte Nannochloropsis were analyzed by high‐performance liquid chromatography with a flame ionization detector. Four major molecular species of triacylglycerol composed of C 14:0, C 16:0, and C 16:1 fatty acids at different combinations were identified. Six molecular species of monogalactosyl diacylglycerol were detected. Three of them contained C 20:5 fatty acid in the sn‐1 position, and one component accommodated C 20:5 fatty acid in both the sn‐1 and sn‐2 positions. Variations in the relative distribution of the molecular species were further monitored in Nannochloropsis cultures grown under different irradiance levels and temperatures. The relative distribution of 16: 0/16:1/16:0 triacylglycerol increased in cells grown in high light and in high temperature. Variations in cellular fatty acid composition in Nannochloropsis grown under different environmental conditions of irradiance level and temperature were attributed to alterations in relative cellular content of lipid classes as well as in the relative composition of lipid class molecular species.
THE CORTICAL MICROTUBULAR CYTOSKELETON OF OXYRRHIS MARINA (DINOPHYCEAE) OBSERVED WITH IMMUNOFLUORESCENCE AND ELECTRON MICROSCOPY1
Authors: Roberts Keith R. , Rusche M. Losoff , Taylor F. J. R. 
Published: October 2004

ABSTRACTThe cortical microtubular cytoskeleton of Oxyrrhis marina Dujardin was investigated using indirect immunofluorescence and transmission electron microscopy. The cortical microtubular cytoskeleton is unlike that of other previously examined dinoflagellates because all cortical microtubules are oriented longitudinally and do not attach or abut tranverse microtubular arrays. This difference is considered along with other morphological and cytological variables as indicative of Oxyrrhis's phylogenetic position relative to the Dinophyceae.
MUCILAGE PROCESSING AND SECRETION IN THE GREEN ALGA CLOSTERIUM. II. ULTRASTRUCTURE AND IMMUNOCYTOCHEMISTRY1
Authors: Domozych David S. , Domozych Catherine Rogers 
Published: October 2004

ABSTRACTWe conducted an ultrastructural and immunocytochemical analysis of the subcellular components involved in mucilage secretion in Closterium. In conventionally fixed cells, the mucilage vesicle appears dense‐cored with an electron‐dense center surrounded by radiating fibrils. In freeze‐substituted cells, the vesicles are highly osmiophilic. These mucilage vesicles are produced from peripheral swellings of the trans face cisternae of the Golgi apparatus (GA). The vesicles apparently move from the GA, found in cytoplasmic depressions between lobes of the plastid, to the sub‐plasma membrane peripheral cytoplasm. Here, they become associated with components of the peripheral cytoskeletal network. The mucilage is ultimately released through flask‐shaped pores in the cell wall.
STRUCTURE AND PHYSIOLOGY OF THE HAPTONEMA IN CHRYSOCHROMULINA (PRYMNESIOPHYCEAE). I. FINE STRUCTURE OF THE FLAGELLAR/HAPTONEMATAL ROOT SYSTEM IN C. ACANTHA AND C. SIMPLEX1
Authors: Gregson Andrew J. , Green J. C. , Leadbeater Barry S. C. 
Published: October 2004

ABSTRACTThe intracellular structural relationships between the flagella and haptonema in Chrysochromulina acantha Leadbeater & Manton (Prymnesiophyceae) were studied in detail and a reconstruction is presented. Three micro‐tubular roots are associated with the flagellar apparatus. The largest, consisting of a sheet of approximately 20 microtubules, has its origins at the base of the left basal body. The main body of microtubules passes over the surface of a mitochondrion toward the left chloroplast and apparently terminates at a pair of microtubules oriented perpendicularly to it. Four microtubules diverge from the sheet and pass behind the left basal body. Two other roots–one consisting of a 2 + 2 + 1 arrangement of microtubules, the other of a single microtubule only—are associated with the right basal body. The two basal bodies are connected by distal and proximal fibers, and they are linked also to the base of the haptonema, three fibers extending from the haptonemal base to the right basal body, one only to the left. An additional fiber extending from the right basal body passes between the left basal body and the base of the haptonema, terminating at the largest microtubular root. Lateral extensions link this fiber to both the left basal body and the haptonematal base. Negative staining of isolated root systems of C. simplex Estep et al. shows that the arrangement of microtubules and fibrous connections is similar to that in C. acantha. The root system of C. acantha is compared to those of other members of the Prymnesiophyceae.
STRUCTURE AND PHYSIOLOGY OF THE HAPTONEMA IN CHRYSOCHROMULINA (PRYMNESIOPHYCEAE). II. MECHANISMS OF HAPTONEMATAL COILING AND THE REGENERATION PROCESS1
Authors: Gregson Andrew J. , Green J. C. , Leadbeater Barry S. C. 
Published: October 2004

ABSTRACTThe axoneme in the free part of the haptonema in Chrysochromulina acantha Leadbeater & Manton and C. simplex Estep et al. consists of seven single microtubules, except in the extreme distal swelling where, in C. simplex, there are only three microtubules. In the extended haptonema, the microtubules are arranged in a ring though they are not evenly spaced, the gap between two of the microtubules being larger than that between any other neighboring pairs. In the coiled haptonema, rearrangement of the microtubules occurs so that the ring becomes distorted and the microtubules form two superposed arcs. A sliding microtubule mechanism is considered as a means by which haptonematal movement might be affected, and this is discussed in relation to the fine structure of both embedded material and negatively stained demembranated cells. We show that haptonematal coiling is dependent on the presence of calcium ions and that an external concentration of between 10−6 and 10−7 M Ca2+ is the threshold below which the frequency of coiling on cell death is reduced. The results of experiments using ethylene bis‐(oxyethylenenitrilo)‐tetracetic acid (EGTA) and lanthanum ions to control extracellular and intracellular Ca2+ concentrations are discussed in terms of both external free calcium and intracellular pools. We also show that haptonematal regeneration following excision begins with a short lag phase. This is followed by a period of rapid growth, decreasing after approximately 4 h. Full haptonematal regrowth is not achieved until after 12–15 h. The rate of haptonematal regeneration is strongly affected when the flagella are regenerating simultaneously. These observations are interpreted in terms of competition for intracellular precursors.
THE PHYCOBILISOME β18 SUBUNIT GENE OF ALLOPHYCOCYANIN IS LOCATED ON THE PLASTID GENOME IN AGLAOTHAMNION NEGLECTUM(RHODOPHYTA) AND CO TRANSCRIBED WITH AN UNIDENTIFIED OPEN READING FRAME1
Authors: Apt Kirk E. , Grossman Arthur R. 
Published: October 2004

ABSTRACTThe gene encoding the β18 subunit of allophycocyanin (apcF) is on the plaqstid genome of the red alga Aglaothamnion neglectum Feldman‐Mazoyer. Immediately 31apcF and on the same transcript is a second open reading frame (ORF100) with homology (49% amino acid identity) to a gene tentatively identified as apcC in Cyanidium caldarium Geitler. The predicted amino acid sequence of the apcF gene product is 36% identical to analogous polypeptides from cyanobacteria. The apcF and ORF100 genes are clustered with other genes encoding phycobilisome polypeptides, which include the genes for the rod‐core linker polypeptide and the α and β subunits of phycoerythrin.