bluuebunny/crossref_metadata_2025 huggingface dataset:
TWO MOTILE STAGES OF CHRYSOCHROMULINA POLYLEPIS (PRYMNESIOPHYCEAE): MORPHOLOGY, GROWTH, AND TOXICITY1
Authors: Edvardsen Bente , Paasche Eystein
Published: October 2004

Eight months after the 1988 bloom of Chrysochromulina polylepis Manton et Parke in Skagerrak and Kattegat, off the coasts of Norway, Sweden, and Denmark, an alternate cell type carrying a scale complement different from that of authentic C. polylepis appeared in some clones isolated from the bloom. The cultures were recloned, and the development of the new clones was monitored. In clones with 100% cells of the alternate type, authentic cells reappeared, suggesting that the alternate cell type is a stage in the life cycle of C. polylepis and that transition between cell types occurs in both directions. Growth rates of clone cultures (termed a cultures) producing exclusively authentic cells, and of clone cultures (termed β cultures), capable of producing the alternate cell type, were compared at various combinations of temperature and photon fluence rate. The β cultures were less tolerant of high temperatures and photon fluence rates (≤20° C, 570 μmol photons·m−2·s−1) than were the α cultures. At lower temperatures and photon fluence rates (≤16° C, ≤90 μmol photons·m−2·s−1ss), β cultures grew better than α cultures. Relative abundance of the two cell types in β cultures changed in an apparently random manner during these experiments. Preliminary results from flow cytometric analyses indicated that cells of the alternate type were about twice the size and contained an equal or smaller amount of DNA per cell compared to the authentic cells. The β cultures were less toxic to Artemia nauplii than were the a cultures. Three other Chrysochromulina species tested were apparently nontoxic.
SEASONAL AND BETWEEN‐PLANT VARIABILITY IN THE MORPHOLOGY OF SARGASSUM MATHIESONII SP. NOV. (PHAEOPHYTA) FROM THE GULF OF MEXICO1
Authors: Kilar John A.
Published: October 2004

Sargassum mathiesonii sp. nov. is described from a population at the mouth of the Homosassa River, Homosassa, Florida. Patterns of morphological variation were quantified as well as the plant's phenology and ontogeny. Sargassum mathiesonii is dioecious (50/50 sex ratio), produces receptacles basipetally along laterals, and has vesicle pedicels that average 1–1.7 mm in length. As judged from coefficients of variation and measurements of between‐plant variation, vesicle diameter was the most stable continuous trait, followed by vesicle length, blade length: width ratio, blade width, and blade length. Anatomical variation was attributed primarily to ontogeny. Plants were smallest in March and April and grew to their maximum size in June (ca. 2 m). Biomass was augmented by additional main axes and primary laterals in October and receptacles in December. At maturity, male receptacles were longer and more loosely branched than female receptacles. A few vesicles developed viable oogonia in their cryptostomata and gave rise to fertile branches, situations previously unknown for Sargassum. Sargassum mathiesonii is determined to be morphologically and developmentally distinct from the lectotype and other North American populations of S. filipendula C. Ag. A more utilitarian approach to Sargassum taxonomy is achievable if species descriptions incorporate an understanding of morphological variability, reproductive periodicity, and ontogenetic patterns.
DISCOVERY OF A FERTILE PELAGOPHYCUS×MACROCYSTIS(PHAEOPHYTA) PUTATIVE HYBRID AND SUBSEQUENT PRODUCTION OF F2 SPOROPHYTES IN THE LABORATORY1
Authors: Coyer James A. , Engle John M. , Zimmerman Richard C.
Published: October 2004

A fertile putative hybrid of Pelagophycus porra (Lem.)Setch. × Macrocystis pyrifera (L.) was discovered in Big Fisherman Cove, Santa Catalina Island, California, in March 1986. The plant possessed a single, solid primary stipe that bifurcated into two secondary stipes, each with a hooked‐shaped pneumatocyst. A total of 15 blades, 14 with sori, were produced on two to three dichotomies above and below each pneumatocyst. Gametophyte development of spores released from sori and the resulting early sporophtes (2–3 mm) were typical of Laminariales. Gametophytes appeared within a day of spore germination, 500‐cell stage sporophytts within 3–4 weeks, and 2–3 mm sporophytes within 5–6 weeks. The cultures expired before branching patterns could be determined.
PATTERNS OF CELL SIZE CHANGE IN A MARINE CENTRIC DIATOM: VARIABILITY EVOLVING FROM CLONAL ISOLATES1
Authors: Armbrust E. Virginia , Chisholm Sallie W.
Published: October 2004

Isolates of the centric diatom, Thalassiosira weissflogii Grun., were maintained in exponential growth under constant, favorable conditions for nearly 2 years. During this interval, each culture underwent periodic increases and decreases in mean cell size, a behavior predicted for diatom populations alternating between sexual and asexual reproduction, respectively. The overall patterns of cell size change displayed by each culture, however, were unique. The maximum size of newly enlarged cells varied among isolates and within a given isolate over time. Consequently, both the timing and rate of increase in mean cell size also varied despite the fact that the minimum average cell size obtained by the various cultures was relatively constant. The most consistent feature among the isolates was the rate of decrease in mean cell size, a value determined by the physical constraints of the diatom frustule during mitotic divisions. We hypothesize that the extent of the variability exhibited by these cultures results from the fact that an inherent feature of diatom populations is a constantly changing genetic composition.
WATER MOTION AND MORPHOLOGY IN CHONDRUS CRISPUS (RHODOPHYTA)1
Authors: Gutierrez Luis M. , Fernández Consolación
Published: October 2004

Morphological variability of intertidalChondrus crispusStackh. fronds along a small open rocky coast was related to wave exposure and emersion. Cluster analysis revealed two well‐defined morphologies: filiform and planiform, named the N morphotype and B morphotype, respectively. We propose a rapid method of classifying fronds based on the morphology of the cross section at half the height on the thallus. The N morphotype is characterized by fewer dichotomies per unit length, a circular cross section with a large inner cortex, and narrow fronds. It is abundant at low intertidal and exposed sites. The B morphotype is characterized by more dichotomies, smaller sizes, a subelliptical or flattened cross section, and broad fronds. It is abundant at high intertidal sites in sheltered areas. Regression analysis revealed a major effect of water movements on frond morphology with respect to tidal level, which was more evident at high intertidal levels. No relationships were observed between morphology and life history phases.
FINE STRUCTURE OF A TERRESTRIAL CYANOBACTERIAL MAT FROM ANTARCTICA1
Authors: Davey Martin C. , Clarke Ken J.
Published: October 2004

The fine structure of a cyanobacterial mat collected from the fellfield ecosystems of Signy Island, Antarctica, was examined using some novel light and scanning electron microscope techniques. The mat was up to 5 mm thick and was distinctly layered. The surface of the mat consisted of nonliving material above a zone of Phormidium autumnale (Ag.) Gom. filaments. We suggest that the surface layer protects the cyanobacterium from the effects of desiccation or high irradiance. Lower layers were less structured than the upper layer and included other taxa of cynobacteria and eukaryotic algae, although still dominated by Phormidium. The lowest layers consisted of dead organic material. The mat bound large amounts of inorganic material within and between the subsurface layers.
EVIDENCE OF AN ORGANIC MATRIX FROM DIATOM BIOSILICA1
Authors: Swift Debbie M. , Wheeler A. P.
Published: October 2004

Most biominerals appear to be composites of organic material and mineral. Whether biosilica is such a composite is unresolved because of a lack of evidence for such organic components. We present evidence that organic material exists within diatom biosilica and can be extracted using HF/NH4F solutions from frustules isolated from Cyclotella meneghiniana Kütz and diatomaceous earth. To eliminate organic casing on the silicified frustules as a source of organic materials, the casing was removed by oxidation of frustules with NaOCl before extraction. The removal of the casing was confirmed in that oxidized frustules no longer displayed the ability to be stained with ruthenium red and fluorescamine. Frustules examined with EDXA showed an emission peak from sulfur before treatment but no peak following treatment, indicating that oxidation removed organic sulfur. The organic material obtained from extracts of fresh frustules contained both soluble and insoluble components. Only soluble material was evident in extracts from diatomaceous earth. The soluble material appears to contain glycoproteins with relatively high levels of serine and glycine. The soluble proteins from fresh frustules also appear to be phosphorylated. Indirect evidence is presented that suggests the soluble proteins may contain regions of primary structure enriched in anionic amino acids. The soluble extracts differ from general cell contents when the two fractions are compared, suggesting that frustules contain specialized organic material. The identification of silica‐specific organic material suggests that mineralization in diatoms may be in part matrix‐mediated.
SEQUENCE AND PHYLOGENY OF THE PSAB GENE OF PYLAIELLA LITTORALIS(PHAEOPHYTA)1
Authors: Assali Nour‐Eddine , Goër Susan Loiseaux‐de
Published: October 2004

The psaB gene codes for one of two highly conserved P700 chlorophyll a apoproteins of photosystem I. This gene was cloned from the brown alga, Pylaiella littoralis (L.) Kjellm., and its primary sequence was determined. The inferred amino acid sequence of the P. littoralis protein was compared to homologous sequences from land plants, green algae, and a cyanobacterium. The psaB protein sequence is very conserved in all the examined taxa, and an unrooted phylogenetic tree, generated from a distance matrix, shows that the P. littoralis gene is closer to that of the cyanobacterium Synechocossus sp. PCC 7002 than are those of green algae, land plants, and Euglena gracilis.
PRINTZINA GEN. NOV. (TRENTEPOHLIACEAE), INCLUDING A DESCRIPTION OF A NEW SPECIES1
Authors: Thompson Rufus H. , Wujek Daniel E.
Published: October 2004

Examination of Trentepohlia Martius species indicated significant morphological diversity within the genus. This diversity forms the basis for the description of a new genus, Printzina Thompson and Wujek. The generic taxonomy is based on the nature of its superficial growth on leaves or twigs and a papilla pore basal on the sporangium, adjacent to the area of attachment. Certain nomen‐clatural treatments were required: the transfer of nine species from Trentepohlia and the description of one new species, Printzina ampla.
DISTRIBUTION AND RECRUITMENT OF SUBTIDAL GENICULATE CORALLINE ALAGE1
Authors: Konar Brenda , Foster Michael S.
Published: October 2004

Geniculate coralline algae are common members of kelp forest communities. The structure provided by their stiff branches greatly influences the abundance and species composition of benthic animals and can affect associated algae by inhibiting recruitment, but the branches are themselves substrate for a large number of other taxa. However, other than qualitative observations, little is known about the within‐site distribution, recruitment, and growth of these algae. We examined the distribution of the dominant corallines at a subtidal site in central California. Abundances of Calliarthron tuberculosum (Post. & Rupr.) Dawson, Bossiella californica ssp. schmittii (Manza) Johans., Calliarthron cheilosporioides Manza, Corallina vancouveriensis Yendo, and unidentifiable juveniles were determined at depths of 10, 15, and 20 m and on horizontal rock, vertical rock, and cobble. Calliarthron tuberculosum was most abundant (≤39% cover) at all depths, growing primarily on horizontal surfaces. Vertical surfaces and cobbles were dominated by B. californica ssp. schmittii (40 and 15% cover, respectively). These two most abundant species had the highest cover at 15 m. Calliarthron cheilosporioides and C. vancouveriensis were relatively rare (<1% cover) and generally grew on horizontal rocks and at shallower depths. Unidentified juveniles were also rare and occurred mainly on horizontal rocks and cobbles at 20 m.

The settlement and growth rates of coralline crusts and the initiation and growth rates of young erect fronds from these crusts were determined in clearings made in the spring and fall at the three depths. Crust densities and diameters were highest at 10 m and in spring clearings. Settlement and growth tended to decrease with increasing depth. Trends were similar in fall clearings, but initial settlement was lower. Initiation and growth of fronds decreased with depth and were also higher in fall clearings. These variations in depth and substrata distribution, as well as settlement and growth, suggest there is considerable variation in the population biology between species in this group of subtidal plants.
FATTY ACID DISTRIBUTION AMONG SOME RED ALGAL MACROPHYTES1
Authors: Levy Israel , Maxim Corina , Friedlander Michael
Published: October 2004

Macrophytic members of the Rhodophyta, which were grown under controlled conditions, were analyzed for their fatty acid distribution. Significant differences were found between some species of the Gelidiales and Gracilariales. Two dominant polyunsaturated fatty acids of the 20 carbon chain group, 20:4ω6 and 20:5ω3, were found in all the Gelidiales species, whereas only 20:4ω6 was found in the Gracilariales species. An inverse relationship between the content of these two polyunsaturated fatty acids in Gelidiales species and among the two groups of species are reported and discussed. All other fatty acid characteristics were more or less similar in these two orders. We cannot draw any solid conclusion about the relationship between Gracilariopsis cf. lemaneiformis (formerly Gracilaria lemaneiformis) and the genus Gracilaria, since our results (the existence of 20:4ω6 and 20:5ω3 in Gracilariopsis) contradict results found by other researchers. The diverse growth conditions of photon flux density and temperature caused some differences in the distribution of the fatty acids in each species. These differences could not explain the different results in similar species reported in the literature.
DEVELOPMENT OF THE ENDOPARASITIC DINOFLAGELLATE AMOEBOPHRYA CERATII WITHIN HOST DINOFLAGELLATE SPECIES1
Authors: Fritz Lawrence , Nass Monica
Published: October 2004

The endoparasitic dinoflagellate Amoebophrya ceratii Koeppen occurs in coastal waters of Nova Scotia within cells of two dinoflagellate hosts, a Scrippsiella species (probably S. trochoidea (Stein) Loeb. III) and Dino‐physis norvegica Claparede & Lachman. We describe the development of the endoparasitic stage (the trophont) of A. ceratii within host cells using light and electron microscopy. After entry into the host, the trophont grows and expands until most of the host cell is occupied by the parasite. Growth is marked by a proliferation of trophont nuclei and flagella and by the formation of numerous lobes, each of which possesses a characteristic dinoflagellate amphiesma. The mature endoparasitic trophont is recognized at the light microscopic level as a beehive‐shaped structure that consists of numerous lobes of the developing motile sporont cells and a mastigocoel cavity containing the sporont flagella.
ORGANIZATION OF THE CHLOROPLAST GENOME OF THE FRESHWATER CENTRIC DIATOM CYCLOTELLA MENEGHINIANA1
Authors: Bourne Carol M. , Palmer Jeffrey D. , Stoermer Eugene F.
Published: October 2004

We constructed a complete physical map and a partial gene map of the chloroplast genome of Cyclotella meneghiniana Kützing clone 1020‐1a (Bacillariophyceae). The 128‐kb circular molecule contains a 17‐kb inverted repeat, which divides the genome into single copy regions of65 kb and 29 kb. This is the largest genome and inverted repeat found in any diatom examined to date. In addition to the 16S and 23S ribosomal RNA genes, the inverted repeat contains both the ndhD gene (as yet unexamined in other diatoms) and the psbA gene (located similarly in one of two other examined diatoms). The Cyclotella chloroplast genome exists as two equimolar populations of inversion isomers that differ in the relative orientation of their single copy sequences. This inversion heterogeneity presumably results from intramolecular recombination within the inverted repeat. For the first time, we map the ndhD, psaC, rpofi, rpoCl, and rpoC2 genes to the chloroplast genome of a chlorophyll c‐containing alga. While the Cyclotella chloroplast genome retains some prokaryotic and land plant gene clusters and operons, it contains a highly rearranged gene order in the large and small single copy regions compared to all other examined diatom, algal, and land plant chloroplast genomes.
SEPARATING TABELLARIA (BACILLARIOPHYCEAE) SHAPE GROUPS BASED ON FOURIER DESCRIPTORS1
Authors: Mou Daiqing , Stoermer Eugene F.
Published: October 2004

A random sample of 490 Tabellaria specimens was analyzed using the harmonic amplitudes of the Fourier transformations of their valve outlines as shape descriptors. Principal component analysis (PCA) was applied to the sample to reduce dimensionality. The problem of non‐normal distribution of these descriptors due to cell division was solved by sub‐sectioning the entire data set based on its distribution on the first three components (PC1, PC2, and PC3) of the overall PCA. Each of the subsets was then analyzed by PCA. Shape groups from subset clusters were compared with one another and then similar groups were congregated into one growth series. Eight distinct shape groups were found. The results agree with some previous classical observations on the genus and at the same time reveal many new morphological characteristics related to valve shape. These new characteristics are impossible to obtain without appropriate specimen sampling, quantitative shape description, and data analysis techniques.
THE ECOLOGY OF CLADOPHORA
Authors: Dodds Walter K. , Gudder Dolly A.
Published: October 2004

Cladophora is found in a variety of marine and fresh‐waters and provides habitat and food for numerous organisms. It may be the most ubiquitous macroalga in fresh‐waters worldwide. This filamentous green alga can reach nuisance levels as a result of cultural eutrophication. Taxonomic identification of Cladophora species is difficult. Taxonomy may be clarified by the simultaneous culture of known taxa and material derived from field collections under the same sets of culture conditions. This should eliminate ecotypic variations in morphology. Cladophora is predominantly benthic and is often found in regions of unidirectional flow or periodic wave action. Its metabolism, and morphology are related to hydrodynamic conditions. Nitrogen and phosphorus are the most commonly reported limiting nutrients. Cladophora is a mid‐ to late successional species in freshwaters where it is grazer resistant. In marine communities, however, it is considered an early opportunist and relatively palatable to invertebrates. Cladophora is colonized by a wide variety of epiphytes and motile animals because it can offer protection from predation, food (in the form of epiphytes or Cladophora itself), or a substrate that is anchored against flow disturbance. Species interactions that occur within Cladophora communities include 1) competition with other primary producers, 2) top‐down control of biomass, 3) association with nitrogen‐fixing epiphytes, 4) grazing on epiphytes by invertebrates, and 5) complicated foodwebs in marine intertidal and freshwater communities. Because Cladophora is found in many different habitats, its ecology varies significantly with locale.
BIOGEOGRAPHY OF STREAM MACROALGAE IN NORTH AMERICA1
Authors: Sheath Robert G. , Cole Kathleen M.
Published: October 2004

In a survey of 1000 20‐m long stream segments in North America from 73°N to 10° N, 259 infrageneric taxa were identified, composed of 35% Chlorophyta, 24% Cyanophyta, 21% Chrysophyta, 20% Rhodophyta, and one species of Phaeophyta. The most common morphological forms were mats (42%), gelatinous colonies (23%), and gelatinous filaments (13%); the majority of taxa were vegetative (78%). The frequency of reproductive states varied among the biomes examined, with the highest values observed as follows: vegetative (85%) in the tundra, sexual (35%) in the deciduous forest, and asexual (21%) in the tropical rainforest. In terms of total species, the tundra had the lowest number (54), the boreal forest had the greatest number (100), and other well‐sampled biomes had 84 to 87. The Chlorophyta had the greatest species numbers in all biomes, and the relative contribution of this division did not vary significantly throughout the continent. With regard to similarity of species composition, the two closest associations were the boreal forest with the western coniferous forest and the eastern hemlock–hardwood forest with the deciduous forest. Species numbers per stream segment ranged from 0 to 11 (X̄= 3.1), cover ranged from 0 to 100% (X̄= 15%), and there was no significant difference in these values among the biomes. The cyanophyte Phormidium retzii (C. Ag.) Gom. was the most widespread species (in 172 segments and all biomes). The majority of species were found in moderate current velocities (X̄= 40 cm X̄ s−1), neutral to slightly alkaline pH (X̄= 7.5), and moderately low ion waters (X̄= 261 μS · cm−1). On both tropical and Arctic islands, there was no significant increase in total species or species numbers per stream segment with increasing surface area.
PURIFICATION AND CHARACTERIZATION OF PYRUVATE KINASE FROM THE GREEN ALGA CHLAMYDOMONAS REINHARDTII1
Authors: Wu Huacheng Bill , Turpin David H.
Published: October 2004

A single form of pyruvate kinase was isolated from the green alga Chlamydomonas reinhardtii Dang. (Chlorophyta) and partially purified over twentyfold, yielding a final specific activity of 2.68 μmol pyruvate produced‐min‐1.mg‐1 protein. Studies of its physical characteristics reveal that the pyruvate kinase is heat stable, is partially inactivated by sulfhydryl reagent N‐ethylmaleimide, and has a pH optimum at 6.8 and a native molecular mass of 224 kDa. Immunological precipitation and western blotting, using antibodies raised against Selenastrum minutum Naeg. (Chlorophyta) cytosolic pyruvate kinase, reveal that C. reinhardtii pyruvate kinase possesses a subunit molecular mass of 57 kDa, indicating a homo‐tetrameric structure. This enzyme exhibits an absolute requirement for a divalent cation that can be fulfilled, by Mg2+. The monovalent cation K+ acts as a strong activator. The Km values for phosphoenolpyruvate and adenosine diphosphate (ADP) are 0.16 mM and 0.18 mM, respectively. The enzyme is capable of using other nucleotides with Vmax for UDP, GDP, IDP, and CDP of 70%, 55%, 53%, and 25% of that with ADP, respectively. Dihydroxyacetone phosphate, ribulose 1,5‐bisphosphate, adenosine monophosphate (AMP), ribose‐5‐phosphate, and glyceraldehyde‐3‐phosphate are activators, whereas glutamate, orthophosphate, adenosine triphosphate (ATP), citrate, isocitrate, malate, oxalate, phosphoglycolate, and 2,3‐diphosphoglycerate are potent inhibitors of this enzyme. Dihydroxyacetone phosphate can reverse the inhibition by glutamate and phosphate. These properties are discussed in light of pyruvate kinase regulation during anabolic and catabolic respiration. Substrate interaction and product inhibition studies indicate that ADP is the first substrate bound to the enzyme and pyruvate is the last product released (Ordered Bi Bi mechanism).
EFFECTS OF VARIATION IN TEMPERATURE. I. ON THE BIOCHEMICAL COMPOSITION OF EIGHT SPECIES OF MARINE PHYTOPLANKTON1
Authors: Thompson Peter A. , Guo Ming‐xin , Harrison Paul J.
Published: October 2004

The influence of temperature on the biochemical composition of eight species of marine phytoplankton was investigated. Thalassiosira pseudonana Hasle and Heim‐dal, Phaeodactylum tricornutum Bohlin and, Pavlova lutheri Droop (three of eight species studied) had minimum values of carbon and nitrogen quotas at intermediate temperatures resulting in a broad U‐shaped response in quotas over the temperature range of 10 to 25°C. Protein per cell also had minimum values at intermediate temperatures for six species. For T. pseudonana, P. tricornutum, and P. lutheri, patterns of variation in carbon, nitrogen, and protein quotas as a function of temperature were similar. Over all species, lipid and carbohydrate per cell showed no consistent trends with temperature.

Only chlorophyll a quotas and the carbon: chlorophyll a ratios (θ) showed consistent trends across all species. Chlorophyll a quotas were always lower at 10°C than at 25°C. Carbon: chlorophyll a ratios (θ) were always higher at 10°C than at 25°C. We suggest that although θ consistently increases at lower temperatures, the relationship between temperature and θ ranges from linear to exponential and is species specific. Accordingly, the interspecific variance in θ that results from species showing a range of possible responses to temperature increases as temperature declines and reaches a maximum at low temperatures. High photon flux densities appear to increase the potential interspecific variance in the carbon: chlorophyll a ratio and therefore exacerbate these trends.
TWO TYPES OF CYTOPLASMIC CLEAVAGE IN THE COENOCYTIC SOIL ALGAPROTOSIPHON BOTRYOIDES(CHLOROPHYCEAE)1
Authors: Kouwets Frans A. C. , van der Schaaf Peter J.
Published: October 2004

Cytokinesis in the coenocytic green algaProtosiphon botryoides(Kütz.) Klebs was studied with transmission electron microscopy. In vegetative cells, nuclei with associated basal bodies and dictyosomes are scattered throughout the cytoplasm. Mature cells may develop either multinucleate resting spores (coenocysts) or uninucleate zoospores. Cytokinesis may be preceded by contraction of the protoplast due to the disintegration of vacuoles that are present in larger, siphonous cells.

The formation of coenocysts in ageing, siphonous cells, is signalled by cleavage of the chloroplast and the development of arrays of phycoplast microtubules in one or more transversely oriented planes through the cell. Nuclei with associated basal apparatuses stay dispersed throughout the cytoplasm; the basal bodies apparently are not involved in organization of the phycoplast. The plasma membrane invaginates, resulting in a centripetal cleavage of the protoplast into two or more multinucleate daughter protoplasts. Simultaneously, wall material is deposited along the outside of the daughter protoplasts by dictyosome‐derived vesicles, and finally two or more thick‐walled coenocysts are formed.

The formation of zoospores, on the other hand, is signalled by clustering of the nuclei in one or more groups depending on the shape of the mother cell. The nuclei become arranged with the associated basal apparatuses facing toward the center of the cluster. Bundles of phycoplast microtubules develop between the nuclei, radiating from the center of a cluster toward the plasma membrane; basal apparatuses or associated structures apparently are involved in organization of the phycoplast. Cleavage furrows grow out centrifugally along these bundles of micro‐tubules, fed by dictyosome‐derived vesicles. No wall material is deposited. An additional mitotic division occurs during cleavage, and finally numerous uninucleate, wall‐less, biflagellate zoospores are formed. The ultrastructural features of the two different types of cytoplasmic cleavage associated with two different types of daughter cells have not previously been reported for chlorophycean algae.
COMPARATIVE PHYSIOLOGY AND BIOCHEMISTRY AND TAXONOMIC ASSIGNMENT OF THE CHLORELLA (CHLOROPHYCEAE) STRAINS OF THE CULTURE COLLECTION OF THE UNIVERSITY OF TEXAS AT AUSTIN1
Authors: Kessler Erich , Huss Volker A. R.
Published: October 2004

The species of the genus Chlorella exhibit considerable biochemical and physiological differences. Therefore, it is important to select for and utilize in research or biotechnology correctly identified strains of the species having the most favorable properties for the respective project. We examined the Chlorella strains of the University of Texas collection at Austin, Texas, according to species‐specific chemotaxonomic characters and assigned 58 strains to 10 well‐established species (only 17 of these strains were correctly named before).
CYCLOMORPHOSIS IN SCENEDESMUS ARMATUS (CHLOROPHYTA): AN ORDERED SEQUENCE OF ECOMORPH DEVELOPMENT1
Authors: Trainor Francis R.
Published: October 2004

Scenedesmus armatus (Chod.) Chod, growth and morphology were monitored in medium 7 (oligotrophic) and Bristol's medium (eutrophic); cultures in both media were incubated at 10 and 22° C. Growth rate at 10° C was reduced, i.e. only one doubling in 7 days in medium 7 and 2.3 doublings in Bristol's, compared to 4.3 and 6 doublings at 22° C over the same period. Unicells as well as cells of colonies were larger at the cold temperature. The lengths of cells were not significantly different regardless of temperature or medium, but cell width was markedly increased at the lower temperature. Additionally, an arcuate, eight‐celled, multispined ecomorph, which resembled several previously described taxa, was produced at 10° C. It becomes a component of a previously published ordered sequence of ecomorph development for this species.

Based on data now accumulated in both the laboratory and the field, these temporal changes are interpreted to be a cyclomorphosis, driven by a coupling of nutrient availability and temperature. Within the addition of new cold temperature (spring) ecomorphs, the ordered sequence of ecomorphs for S. armatus is a succession from unicells to multispined eight‐celled colonies to quadricaudate colonies, ending with acaudate four‐celled ecomorphs.
CULTURE STUDIES ON THE RELATIONSHIP BETWEENSCHIZYMENIAANDHAEMATOCELIS(GIGARTINALES, RHODOPHYCEAE) FROM THE PACIFIC COAST OF NORTH AMERICA1
Authors: DeCew Thomas C. , Silva Paul C. , West John A.
Published: October 2004

Carpospores fromSchizymenia pacifica(Kylin) Kylin (Gymnophlaeaceae) from California formed crusts anatomically identical toHaematocelis rubensJ. Agardh (Cruoriaceae). Tetraspores ofH. rubensfrom Monterey, California, and Baja California, Mexico, germinated to form basal discs from which arose upright multiaxial blades with a filamentous medulla and cortical gland cells. Pro‐carps and spermatangia were present on the same blades; subsequently, cystocarps characteristic ofSchizymenia pacificadeveloped. Re‐examination of herbarium specimens suggests that the foliose tetrasporangial phases previously reported asS. pacificaare referable toHalymenia, Dilsea, Cryptonemia, orTurnerella. Schizymenia pacifica(type locality: San Juan Islands, Washington) thus is considered to be the gametophyte in the life history ofHaematocelis rubens(type locality: Brest, France), which has also been reported to be the tetrasporophyte ofS. dubyi(Chauvin ex Duby) J. Agardh (type locality: Cherbourg, France). Atlantic and Pacific gametophytes and tetrasporophytes are anatomically very similar, suggesting that only one species is involved, but critical studies must be made before a decision on this taxonomic question can be reached.Haematocelis zonalisDawson et Neushul (type locality: Anacapa Island, California) is considered to be a growth form of the tetrasporangial phase ofS. pacifica.
A METHOD OF OBTAINING AXENIC CULTURES OF TRENTEPOHLIA SPP. (CHLOROPHYTA)1
Authors: Lim Melin , Ong Bee‐Lian , Wee Yeow‐Chin
Published: October 2004

Axenic cultures of Trentepohlia species are necessary for the study of growth and hysiological characters of the algae. We describe the use of a Sherman micromanipulator to isolate filaments from samples of T. aurea and T. odorata collected from their natural habitats. These filaments were then used as inocula for the establishment of axenic cultures. In the case of T. aurea, further treatment with lactic acid was necessary.
THE FLAGELLAR APPARATUS OFHYMENOMONAS CORONATA(PRYMNESIOPHYTA)1
Authors: Roberts Keith R. , Mills Jimmy T.
Published: October 2004

The ultrastructure ofHymenomonas coronataMills was reinvestigated to determine the microarchitecture of the flagellar apparatus. Cell morphology and flagellar apparatus structure are very similar to those ofPleurochrysis.Some important variations occur. First, a crystalline root (= compound root) is absent on microtubular root 1. Second, a two‐stranded microtubular root emanates at a right angle from microtubular root 2. Third, a fibrous root emanates from the dorsal region between the basal bodies and extends to the cell's right, paralleling microtubular root 3. These similarities and variations in flagellar apparatus characters are discussed in reference to known variations in the Prymnesiophyta.
VEGETATIVE GROWTH OF ACETABULARIA ACETABULUM (CHLOROPHYTA): STRUCTURAL EVIDENCE FOR JUVENILE AND ADULT PHASES IN DEVELOPMENT1
Authors: Nishimura Nathan J. , Mandoli Dina F.
Published: October 2004

We characterized vegetative development in two inbred cell lines of Acetabularia acetabulum (L.) Silva. Cell growth occurred at the apex and by elongation of older interwhorls throughout vegetative development. Although cell length and hairs per whorl increased regularly during development, interwhorl length, hair persistence on the stalk, and complexity of each whorl (degree of branching of whorl hairs) showed sharp discontinuities during development in both cell lines. The first (earliest) discontinuity, formation of a short interwhorl, was the sixth interwhorl made in all cells. Even though cell line Aa1055 was twice the height ofAa4010 when mature, cells in both lines were 0.8–1.0 cm tall after formation of the short interwhorl. The second discontinuity, increases in hair persistence on the stalk and complexity of each whorl of hairs, began shortly before cap initiation. We propose the following nomenclature: 1) that slower growth before formation of the short interwhorl be called “juvenile”; 2) that more rapid growth after formation of the short interwhorl be called “adult”; and 3) that adult growth be separated into “early” and “late” phases by the discontinuities in whorl hair characteristics. The proposed developmental phases (juvenile, early adult, and late adult) are temporally sequential and spatially stacked.
MORE MOSSES WITH CHLOROCHYTRIUM1
Authors: Reese William D.
Published: October 2004

The green alga Chlorochytrium is reported intracellular in the mosses Archidium tenerrimum Mitten (Archidiaceae) and Funaria hygrometrica Hedwig (Funariaceae).
DNA EXTRACTION METHODS FOR KELP (LAMINARIALES) TISSUE1
Authors: Mayes Charlene , Saunders Gary W. , Tan Ian H. , Druehl Louis D.
Published: October 2004

Newly adapted extraction methods for harvesting total cellular DNA from kelp (Laminariales; Phaeophyta) exploit the life‐history stages of these heteromorphic algae. Earlier techniques, developed primarily for chloroplast DNA extraction, were time consuming and labor intensive and required large quantities of fresh sporophyte tissue. In contrast, the new methods expedite DNA extraction by employing dried sporophyte laminae or fresh gametophyte filaments and meiospores. The current methods require less tissue and procedural manipulation, reducing the time and labor involved in DNA extraction. Additionally, the current methods were successfully employed to extract DNA from herbarium specimens up to 22 years old. Total cellular DNA yields were 12.8 and 26.4 μg:g−1 from dried laminae,: 1.9 and 11 μg from small volumes of concentrated gametophyte filaments (25 μL), and 43 to 54.5 μg from pellets of isolated meiospores (50 μL). Following purification on Sepharose columns, DNA from all three sources was sufficiently pure for molecular applications, including restriction endonuclease digestion, Southern blot‐hybridizations, and amplification via the polymerase chain reaction.
LITHIUM CHLORIDE EXTRACTION OF DNA FROM THE SEAWEED PORPHYRA PERFORATA (RHODOPHYTA)1
Authors: Hong Yong‐Ki , Coury Daniel A. , Polne‐Fuller Miriam , Gibor Aharon
Published: October 2004

Lithium chloride facilitates the softening of cell walls resulting in a simple, quick (2 h) method for DNA extraction from the red seaweed Porphyra perforata J. Agardh. A 5‐min treatment of tissues in Lid at 55°C extracts DNA that is relatively free of the viscous polysaccharides and proteins that are usually coextracted in large amounts from cell walls and cytoplasm. This protocol does not require grinding of tissues, hydroxyapatite binding, cetyl trimethyl ammonium bromide treatments, enzymatic treatments, phenol extraction, or CsCl‐gradient centrifugation. The resulting DNA is of sufficient quality to be used as a template for polymerase chain reaction amplification.
THE INFLUENCE OF SALINITY AND TEMPERATURE COVARIATION ON THE PHOTOPHYSIOLOGICAL CHARACTERISTICS OF ANTARCTIC SEA ICE MICROALGAE1
Authors: Arrigo Kevin R. , Sullivan Cornelius W.
Published: October 2004

The responses of sea ice microalgae to variation in ambient irradiance (0 to 150 μE · m−2· s−1), temperature (–6° to + 6° C), and salinity (0 to 100 ppt) were tested to determine whether these variables act independently or in concert to influence rates of microalgal photosynthesis. The photosynthetic efficiency and maximum photosynthetic rate for sea ice microalgae increased as a function of incubation temperature between ‐6° and + 6° C. Furthermore, photosynthetic efficiency, maximum photosynthetic rate, and quantum yield were greatest at salinities between SO and 50 ppt. In contrast, the mean specific absorption coefficients were lowest near seawater salinities, and the saturating irradiance, Is, appeared to be inversely proportional to salinity. Results also suggest that the effects of salinity on the growth of sea ice microalgae are independent of those elicited by temperature or light, and that the functional relationship between salinity and light or temperature is multiplicative. This information is essential to the proper formulation of algorithms used to describe algal growth in environments where light, temperature, and salinity are changing simultaneously, such as within sea ice or within the water column at the marginal ice edge zone.
DAY AND NIGHT KINETICS OF GROWTH RATE IN GREEN, BROWN, AND RED SEAWEEDS1
Authors: Lüning Klaus
Published: October 2004

Growth rates in terms of area increase per 30 min were measured in flat thalli of several seaweed, species by means of computer‐assisted image analysis, at 12 h light per day and a photon fluence rate of 20 μmol · m‐2· s−1. Light fields included white fluorescent, imitated underwater, blue, green, and red light. In the green alga Ulva pseudocurvata Koeman et Hoek, blue light caused an immediate reduction of thallus area and growth rate after the onset of light, whereas green light and red light resulted in an initial peak in growth rate followed by inhibition 60 min after the onset of light. More growth was observed in darkness than in blue light in U. pseudocurvata. All brown and red algae tested, with Laminaria saccharina (L.) Lamour. and Palmaria palmata Stackh. as the main investigated species, grew faster during the day than during the night, irrespective of light quality during the main light phase. The upper intertidal red alga Porphyra umbilicalis (L.) J. Ag. achieved most of its thallus expansion per 24 h during the first 3 h of the light phase, with maximum growth rates of 2–3% increase in area per hour. Maximal growth rates were 0.7% for juvenile laminarian sporophytes and were lower than this in Palmaria palmata and other perennial red algae. The temporary growth inhibition by light in Ulva pseudocurvata suggests photomorphogenetic events, similar to the kinetics of stem elongation in higher plant seedlings after blue or red light pulses in darkness.
ORIENTATION OF SWIMMING FLAGELLATES BY SIMULTANEOUSLY ACTING EXTERNAL FACTORS1
Authors: Kessler John O. , Hill Nicholas A. , Häder Donat‐P.
Published: October 2004

The directionality of phototaxis combined with gravitaxis was investigated experimentally for populations of the swimming alga Euglena gracilis Klebs. Two irradiances were used: a “weak” irradiance to elicit positive phototaxis and a “strong” irradiance to elicit negative phototaxis. In addition, by changing the density of cells in the suspension, the number of collisions between cells was varied to determine the effects of these collisions on the distribution of swimming directions in both the absence and the presence of illumination. We found that positive phototaxis was associated with a broader distribution of swimming directions than was negative phototaxis. In the latter case, the effect of phototaxis dominated over that of gravitaxis. Experiments on another swimming alga, Chlamydomonas nivalis Wille, showed that collisions between cells degraded the directionality of gravitaxis.
ISOLATION AND PRELIMINARY CHARACTERIZATION OF THREE CHLAMYDOMONAS STRAINS INTERFERTILE WITH CHLAMYDOMONAS REINHARDTII (CHLOROPHYTA)1
Authors: Spanier Jonathan G. , Graham Jennifer E. , Jarvik Jonathan W.
Published: October 2004

Three new strains of the unicellular green alga Chlamydomonas reinhardtii Dangeard were isolated from soil. The isolates differed from one another and from standard laboratory strains of C. reinhardtii in a number of traits, including heavy metal resistance, protein composition, and mitochondrial DNA length. The new isolates also exhibited distinctive restriction fragment length polymorphisms in their nuclear, chloroplast, and mitochondrial genomes. The new isolates were interfertile with the standard laboratory strains and appeared to transfer chloroplast and mitochondrial genomes in a similar manner, that is, predominantly from the material (mt+) and paternal (mt−) parents, respectively.
TAXONOMIC STUDY OF MARINE OSCILLATORIACEAN STRAINS (CYANOBACTERIA) WITH NARROW TRICHOMES. II. NUCLEOTIDE SEQUENCE ANALYSIS OF THE 16S RIBOSOMAL RNA1
Authors: Wilmotte Annick , Turner Seán , Van de Peer Yves , Pace Norman R.
Published: October 2004

Partial 16S ribosomal RNA sequences from five marine oscillatoriacean strains with narrow trichomes were determined by a dideoxynucleotide‐termination method. A phenogram was constructed by a distance matrix method including a bootstrap analysis. In addition, a consensus tree was built using cladistic analysis. The results were largely congruent and indicate that the five strains belong to two different lineages. The first lineage groups four phycoerythrin‐producing strains with the strain PCC7375 (“Phormidium ectocarpi Gomont”). The second cluster groups strain PCC7105 (“Oscillatoria williamsii Drouet”) with the previously studied strain Microcoleus 10mfx. Comparisons to morphological data are made and the taxonomic level of the separations is estimated.
REPLICATION OF CHLORELLA VIRUS PBCV‐1 AND HOST KARYOTYPE DETERMINATION STUDIED WITH PULSED‐FIELD GEL ELECTROPHORESIS1
Authors: McCluskey Kevin , Graves Michael V. , Mills Dallice , Meints Russel H.
Published: October 2004

We demonstrated the time‐course of DNA replication of the 330‐kbp Chlorella virus PBCV‐1 by pulsed‐field gel electrophoresis. Viral DNA replication began between 90 and 120 min postinfeclion in cell samples produced without first removing cell walls. The host nuclear genome was degraded beginning almost immediately after infection, but some host DNA remained even after 360 min postinfection. The karyotype of the host alga consisted of nine resolvable bands that we presume to represent 13 chromosomes based on band intensity. The chromosomes ranged in size from 1.1 to 6.5 megabase pairs (Mbp). A summation of the sizes of the bands predicts a genome size of 39–45 Mbp of DNA.
DISTRIBUTION AND SYSTEMATICS OF THE FRESHWATER GENUS TUOMEYA (RHODOPHYTA, BATRACHOSPERMACEAE)1
Authors: Kaczmarczyk Donald , Sheath Robert G. , Cole Kathleen M.
Published: October 2004

Twenty‐seven populations of Tuomeya, including the types of Tuomeya fluviatilis Harvey and Baileya americana Kützing, were analyzed from the entire known range of the genus: northern Newfoundland to northern Florida and east of the Mississippi River. Key morphological features were examined in detail since it has been recently proposed that Tuomeya should be reduced to a section of the genus Batrachospermum. Our observations confirmed the presence of several characteristics unique to Tuomeya: gametophyte development from a basal mass of undifferentiated cells rather than a chantransia stage, pseudoparenchymatous growth, and carpogonia with obliquely to perpendicularly attached trichogynes. Based on these findings, we conclude that the genus Tuomeya should be retained. Using multivariate morphometrics, two groupings were found that differed significantly in plant length (X = 14.1 and 24.1 mm, respectively). However, since there was no other morphometric, environmental, or geographic basis for separation of the groupings, only one species is recognized, T. americana (Kützing) Papenfuss. Populations tend to occur in large streams (>2.8 m wide) with low ion content (≤ 100 μS · cm−1).
LIFE CYCLE OF A STEPHANODISCUS SP. (BACILLARIOPHYTA)1
Authors: Jewson David H.
Published: October 2004

Studies of the life cycle of a centric diatom, tentatively identified as Stephanodiscus neoastraea Håkansson & Hickel, showed that sexual reproduction occurred every year in a freshwater lake (Lough Neagh, Northern Ireland). Male and female gametes were produced in cells below 55% of the maximum diameter during a 3–4‐week period in late summer, following the return of nitrate concentrations above 10 μM NO3‐N. The frequency of sexual reproduction was linked to the cycle of diameter size reduction and regeneration. The times of largest decreases in cell diameter were during nutrient stress in summer and low light conditions in late autumn, rather than during the main spring growth period. So, environmental conditions (combined with the limited life‐spans of individual cells) affected the rate of diameter reduction and, therefore, the length of the life cycle (3–4 years).
A review of the efficacy and safety of opioid analgesics post‐craniotomy*
Authors: Roberts Gemma
Published: October 2004

• Codeine phosphate is the most commonly used analgesic post‐craniotomy

• It is argued, in this paper, that codeine phosphate is an unpredictable pro‐drug that does not equate to a safe and effective method of providing analgesia post‐craniotomy

• Lack of evidence supporting tramadol's usage and concerns over its interactions and side effects mean its use cannot be advocated

• The traditional justification for withholding morphine in post‐craniotomy pain appears to be largely based on anecdotal evidence

• Raising awareness among critical care nurses of the pharmacological properties of the analgesics used is imperative, if post‐craniotomy pain is to be adequately treated

• There is an explicit challenge to the neurosurgical community to re‐evaluate their pain‐management strategies in the post‐craniotomy patient