bluuebunny/crossref_metadata_2025 huggingface dataset:
CHARACTERIZATION OF A NUCLEAR‐ENCODED PHOTOGENE FOR A CHLOROPLAST RNA POLYMERASE SIGMA FACTOR IN THE UNICELLULAR ALGA CYANIDIUM CALDARIUM (RHODOPHYTA)
Authors: Liu Bin , Tan Shi , Troxler Robert F.
Published: March 2003

Previously we identified the gene (rpoD1) for a σ factor of chloroplast RNA polymerase from the unicellular rhodophyte Cyanidium caldarium Geitler and presented evidence for a multigene family of σ factors in this organism. In the present investigation, a new member of this gene family, rpoD2, was isolated and characterized. This gene was identified in a subgenomic library screened with the “rpoD box” probe, a highly conserved 28‐base sequence found in the −10 promoter recognition motif of σ factors from eubacteria and cyanobacteria. Alignment of the deduced amino acid sequence of RpoD2 (the gene product of rpoD2) with other σ factors from C. caldarium showed that this protein contained all four conserved regions found in eubacterial and cyanobacterial σ factors in addition to a newly identified conserved domain. Northern analyses showed that rpoD2 transcripts were not detectable in dark‐grown cells but were enriched in polyA+ RNA from illuminated cells, which suggests that rpoD2 is a positively regulated, nuclear‐encoded photogene. The patterns of rpoD2 and rpoD1 transcript accumulation after transfer of cells from dark to light were distinct, which suggests that σ‐factor genes are differentially expressed. Collectively, the results obtained support the hypothesis that differentially expressed, nuclear‐encoded σ factors may transcribe subsets of plastid genes for photosynthesis during chloroplast development.
SYSTEMATIC STATUS AND PHYLOGENETIC RELATIONSHIPS OF THE FRESHWATER GENUS BALBIANIA (RHODOPHYTA)
Authors: Sheath Robert G. , Müller Kirsten M.
Published: March 2003

The freshwater rhodophyte Balbiania investiens (Lenormand) Sirodot was collected as an epiphyte of Batrachospermum in small streams in England, Ireland, and Germany. Unialgal cultures and field collections of Balbiania were analyzed in terms of their morphology, ultrastructure, and the DNA sequences of the genes coding for the large subunit of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (rbcL) and 18S ribosomal RNA (rRNA), as well as the first internal transcribed spacer region (ITS1) of the rRNA genes. One of the major distinguishing features of this genus is the production of spermatangia on the tips of specialized, elongate cells. The spermatangia are cut off in a cluster together with similar nonspermatangial cells that are packed with starch granules. The only other rhodophyte genus with this feature is Rhododraparnaldia; the two genera are differentiated from each other by the pattern of branching, substratum of attachment, and type of diploid phase. In the parsimony and distance trees inferred from the two gene sequences as well as in a combined parsimony tree, Balbiania and Rhododraparnaldia grouped together on a well‐supported branch separate from other taxa of the Batrachospermales, Acrochaetiales, Nemaliales, and Palmariales. However, the two genera are positioned within a clade containing the last three orders. Based on these findings, it is clear that the genus Balbiania is a valid taxon and that it is phylogenetically associated with Rhododraparnaldia. A new order is proposed, the Balbianiales. The two specimens of Balbiania analyzed from England and Germany have identical sequences for all regions of DNA analyzed.
DETECTION OF THE TOXIC DINOFLAGELLATE ALEXANDRIUM FUNDYENSE (DINOPHYCEAE) WITH OLIGONUCLEOTIDE AND ANTIBODY PROBES: VARIABILITY IN LABELING INTENSITY WITH PHYSIOLOGICAL CONDITION
Authors: Anderson Donald M. , Kulis David M. , Keafer Bruce A. , Berdalet Elisa
Published: March 2003

The toxic dinoflagellate Alexandrium fundyense Balech was grown under temperature‐ and nutrient‐limited conditions, and changes in labeling intensity on intact cells were determined for two probe types: an oligonucleotide probe targeting rRNA and a monoclonal antibody (MAb) targeting a cell surface protein. In nutrient‐replete batch culture, labeling with the rRNA probe was up to 400% brighter during exponential phase than during stationary phase, whereas MAb labeling did not change significantly with growth stage at the optimal growth temperature. In cultures grown at suboptimal, low temperatures, there was a significant difference between labeling intensity in stationary versus exponential phase for both probe types, with exponential cells labeling brighter with the rRNA probe and slightly weaker with the MAb. The decrease in rRNA probe labeling with increasing culture age was likely due to lower abundance of the target nucleic acid, as extracted RNA varied in a similar manner. With the MAb and the rRNA probes, slower growing cultures at low, nonoptimal temperature labeled 35% and 50% brighter than cells growing faster at warmer temperatures. Some differences in labeling intensity per cell disappeared when the data were normalized to surface area or volume, which indicated that the number of target antigens or rRNA molecules was relatively constant per unit area or volume, respectively. Slow growth accompanying phosphorus and nitrogen limitation resulted in up to a 400% decrease in labeling intensity with the rRNA probe compared to nutrient‐replete levels, whereas the MAb labeling intensity increased by a maximum of 60%. With both probes, labeling was more intense under phosphorus limitation than under nitrogen limitation, and for all conditions tested, labeling intensity was from 600% to 3600% brighter with the MAb than with the rRNA probe. Thus, it is clear that significant levels of variability in labeling intensity can be expected with both probe types because of the influence of environmental conditions and growth stage on cellular biochemistry, cell size,rRNA levels, and the number or accessibility of cell surface proteins. Of the two probes tested, the rRNA probe was the most variable, suggesting that in automated, whole‐cell assays, it can be used only in a semiquantitative manner. For manual counts, the human eye will likely accommodate the labeling differences. The MAb probe was less variable, and thus should be amenable to both manual and automated counts.
RIBOSOMAL RNA HETEROGENEITY AND IDENTIFICATION OF TOXIC DINOFLAGELLATE CULTURES BY HETERODUPLEX MOBILITY ASSAY
Authors: C. Paulina Uribe , Suárez‐Isla Benjamín A. , Espejo Romilio T.
Published: March 2003

The heteroduplex mobility assay (HMA) reveals sequence dissimilarity between DNA by measuring the retarded migration of the hybrid or heteroduplex using polyacrylamide gel electrophoresis. Heterogeneity in some cultures of toxic dinoflagellates of the genus Alexandrium (Halim) Balech was observed during comparison of the amplified D1–D2 region of the large subunit rRNA gene (rDNA) using this method. HMA also allowed grouping of clones obtained from toxic bloom events in the Chilean, southernmost Pacific within the Asian Southern Pacific lineage of A. catenella (Whedon et Kofoid) Balech. The applied methodology provides a rapid and simple tool for use in assessing heterogeneity as well as for molecular grouping of strains among the genus Alexandrium.
NO DELETERIOUS ALTERATIONS IN POSIDONIA BEDS IN THE BAY OF MENTON (FRANCE) EIGHT YEARS AFTER CAULERPA TAXIFOLIA COLONIZATION
Authors: Jaubert Jean M. , Chisholm John R. M. , Ducrot Danielle , Ripley Herb T. , Roy Laura , Passeron‐Seitre Gilles
Published: March 2003

High‐resolution multispectral imagery, aerial photography, and SCUBA diving surveys were used to determine if there had been any significant alteration in the dimensions of Posidonia oceanica beds in the Bay of Menton, French Riviera, since colonization of the green alga Caulerpa taxifolia began in the late 1980s. After 8 years of direct contact, there was no evidence of a decrease in the abundance of P. oceanica. On the contrary, the integrity of a seagrass bed had increased in the first area colonized by Caulerpa taxifolia on the eastern side of Cape Martin and, in a more recently colonized central part of the bay, established tufts of Posidonia were isolated from the alga by well‐defined exclusion zones.
NOTE MOLECULAR ANALYSIS OF THE AHAS GENE OF PORPHYRIDIUM SP. (RHODOPHYTA) AND OF A MUTANT RESISTANT TO SULFOMETURON METHYL
Authors: Lapidot Miri , Raveh Dina , Sivan Alex , Arad Shoshana Malis , Shapira Michal
Published: March 2003

Acetohydroxyacid synthase (AHAS) is the target enzyme of the sulfonylurea herbicides, and here we report the sequence of the gene from wild‐type and herbicide‐resistant Porphyridium sp. (Rhodophyta). The resistant mutant has a single residue substitution at a position known to confer herbicide resistance in E. coli and in plants. The rhodophyte gene is of cyanobacterial origin and distinct from the nuclear‐encoded chlorophyte gene, which may be of mitochondrial origin.
CRYOANALYTICAL STUDIES OF FREEZING DAMAGE AND RECOVERY IN FUCUS VESICULOSUS (PHAEOPHYCEAE)
Authors: Speransky Vladislav V. , Speransky Svetlana R. , Brawley Susan H.
Published: March 2003

Receptacles of Fucus vesiculosus L. were examined using cryoscanning electron microscopy of rapidly frozen, hydrated tissue to avoid extraction and collapse of the extracellular matrix (ECM) and provide new structural information. The pore of the conceptacle was occluded by the tightly appressed tips of the paraphyses. These were embedded in copious ECM within the conceptacle. The ECM inside the conceptacle and in the medulla differed markedly in texture and with respect to the distribution of S and Cl, as revealed by energy‐dispersive X‐ray microanalysis. High levels of S were restricted to the conceptacle’s ECM, whereas the ECM in the medulla was always S poor and Cl rich. Receptacles frozen naturally at low tide during the winter of 1998 showed extensive damage in the medulla, and this likely accounts for the cessation of reproduction during the winter on the Maine shore. The damaged receptacles recovered and resumed growth during the spring, and they released gametes by May. Abscission of the overwintered receptacles was observed in June to July, coincident with the formation of new receptacles at the tips of newly grown portions of the fronds.
A PHAGOTROPHICALLY DERIVABLE GROWTH FACTOR IN THE PLASTIDIC DINOFLAGELLATE GYRODINIUM RESPLENDENS (DINOPHYCEAE)
Authors: Skovgaard Alf
Published: March 2003

The marine dinoflagellate Gyrodinium resplendens Hulburt is a mixotroph. It possesses chloroplasts and is photosynthetic, and it also feeds phagotrophically on another dinoflagellate, Prorocentrum minimum (Pavillard) Schiller. The species could be cultivated only in food‐replete cultures. When kept in cultures without food, cellular chl a content and photosynthetic activity of G. resplendens decreased and growth ceased after a few days. In food‐replete cultures, G. resplendens could grow strictly heterotrophically in darkness, but growth rate was then three times lower than in food‐replete cultures kept in light. It is suggested that the main importance of phagotrophy is to acquire a growth factor essential to photosynthetic growth. The addition of soil extract or amino acids to the growth medium induced enhanced photosynthetic growth of the species even without the presence of particulate food, but only for approximately 2 weeks. Long‐term starvation of G. resplendens led to loss of the ability to feed, and therefore starved cells eventually reached a point of no return where neither photosynthesis nor phagotrophy could sustain further growth. Light microscopical observations on G. resplendens revealed new morphological and behavioral details of the species.
TAXONOMY AND PHYLOGENY OF OSMUNDEA (RHODOMELACEAE, RHODOPHYTA) IN ATLANTIC EUROPE
Authors: Nam Ki Wan , Maggs Christine A. , McIvor Lynne , Stanhope Michael J.
Published: March 2003

Two species of Osmundea Stackhouse (Rhodomelaceae, Rhodophyta) that occur in Atlantic Europe have been confused under the names Osmundea ramosissima (Oeder) Athanasiadis and Osmundea truncata (Kützing) Nam et Maggs, regarded until now as a synonym of O. ramosissima. An epitype from its type locality (Stavanger, Norway) is selected for Osmundea ramosissima Athanasiadis, recognized here as a valid name for Fucus ramosissimus Oeder, nom. illeg. Details of vegetative and reproductive morphology of O. ramosissima are reported, based on material from France, the British Isles, and Helgoland. Osmundea ramosissima resembles other species of Osmundea in its vegetative axial segments with two pericentral cells and one trichoblast, spermatangial development from apical and epidermal cells (filament type), the formation of five pericentral cells in the procarp‐bearing segment of the female trichoblast, and tetrasporangial production from random epidermal cells. Among the species of Osmundea, O. ramosissima is most similar to O. truncata. Both species have discoid holdfasts, secondary pit connections between epidermal cells, and cup‐shaped spermatangial pits. They differ in that: (a) O. ramosissima lacks lenticular wall thickenings and refractive needle‐like inclusions in medullary cells, both of which are present in O. truncata; (b) O. ramosissima has branched spermatangial filaments that terminate in a cluster of several cells, whereas in O. truncata the unbranched spermatangial filaments have a single large terminal sterile cell; and (c) cystocarps of O. ramosissima lack protuberant ostioles but ostioles are remarkably protuberant in O. truncata. Phylogenetic analyses of rbcL sequences of Laurencia obtusa (Hudson) Lamouroux and all five Atlantic European species of Osmundea, including the type species, strongly support the generic status of Osmundea. Osmundea ramosissima and O. truncata are closely related (5.2% sequence divergence) and form a well‐supported clade sister to a clade consisting of O. pinnatifida (Hudson) Stackhouse, O. osmunda Stackhouse and O. hybrida (A. P. de Candolle) Nam. The formation of secondary pit connections between epidermal cells is a synapomorphy for the O. ramosissima+O. truncata clade. The close relationship between species with cup‐shaped spermatangial pits (Osmundea hybrida) and urn‐shaped pits (Osmundea pinnatifida and Osmundea osmunda) shows that spermatangial pit shape is not an important phylogenetic character. Parsimony analysis of a morphological data set also supports the genus Osmundea but conflicts with the molecular trees in infrageneric relationships, placing O. hybrida basal within the Osmundea clade and grouping O. osmunda and O. pinnatifida but not O. truncata and O. ramosissima. A key to Osmundea species is presented.
A CALCIUM‐DEPENDENT PROTEIN KINASE FUNCTIONS IN WOUND HEALING IN VENTRICARIA VENTRICOSA (CHLOROPHYTA)
Authors: Sugiyama Koh‐ichi , Mori Izumi C. , Takahashi Koji , Muto Shoshi , Shihira‐Ishikawa Ikuko
Published: March 2003

The cytoplasm around a wound made in the multinucleate unicellular green alga Ventricaria ventricosa (  J. Agardh) Olsen et West formed an aggregation‐ring surrounding the wound immediately after injury. A contraction of the ring then brought about wound healing in culture medium containing Ca2+. Involvement of a calcium‐dependent protein kinase (CDPK) as a regulator of wound healing was examined using an anti‐Dunaliella tertiolecta CDPK antibody. A 52‐kDa protein cross‐reacting with the antibody was detected by Western blotting. Protein kinases of 60 kDa and 52 kDa, which were markedly activated by Ca2+, and a 40‐kDa Ca2+‐independent protein kinase were detected by an in‐gel protein kinase assay using myelin basic protein as the substrate. A 52‐kDa band with Ca2+‐dependent protein kinase activity was immunoprecipitated from the cytoplasmic extract, indicating that these 52‐kDa proteins are identical and possess CDPK activity. Microscopic observation showed that the contraction of the aggregation ring was suppressed by application of the anti‐CDPK to the culture medium. A protein kinase inhibitor, K‐252a, and the calmodulin inhibitors, calmidazolium and compound 48   /   80, which inhibit CDPK activity, also suppressed the contraction of the aggregation‐ring. Immunofluorescence microscopy showed a similar distribution of 52‐kDa CDPK to the distribution of f‐actin, which was randomly distributed in an intact cell and formed a bundle during wound healing. Further, f‐actin was not recruited after injury in the presence of the antibody to CDPK. These results suggest that the 52‐kDa CDPK functions as a Ca2+ receptor in wound healing and simultaneously participates in the organization and contraction of f‐actin to heal the wound.
CLONING OF A cDNA ENCODING A 66‐kDa Ca2+‐DEPENDENT PROTEIN KINASE (CDPK) FROM DUNALIELLA TERTIOLECTA (CHLOROPHYTA)
Authors: Pinontoan Reinhard , Yuasa Takashi , Anderca Marinela I. , Matsuoka Takashi , Uozumi Nobuyuki , Mori Hitoshi , Muto Shoshi
Published: March 2003

A cDNA clone encoding a Ca2+‐dependent protein kinase (DtCPK1) with a calculated molecular mass of 65,746 Da was isolated by sequential immuno‐ and hybridization‐screening from a cDNA library of the halotolerant green alga, Dunaliella tertiolecta Butcher (Chlorophyceae). Primary structure analysis of DtCPK1 revealed a long variable domain preceding a catalytic domain, an autoinhibitory junction domain, and a C‐terminal calmodulin‐like domain containing 4 EF‐hand motifs. Database searches showed that DtCPK1 has a high similarity to CCK1, a CDPK from the green alga, Chlamydomonas eugamentos Moewus. The N‐terminal long variable domain of DtCPK1 contains neither the N‐myristoylation motif, which is found in many CDPKs, nor the PEST motif, which is associated with rapid protein turnover and found in one CDPK subfamily. However, a putative Ca2+‐dependent lipid binding domain that might be responsible for the association of cytosolic DtCPK1 with the cell membrane was identified in the variable domain. Three CDPKs, with molecular masses of 62, 54, and 47 kDa respectively, were observed in an in‐gel protein kinase assay of D. tertiolecta cells extract. No change in the activities of these CDPKs were observed for up to 30 min after D. tertiolecta cells had been subjected to a hypoosmotic shock. An antibody raised against a CDPK purified from D. tertiolecta and used to isolate the DtCPK1 cDNA clone cross‐reacted strongly with the 62‐kDa CDPK but weakly with the 54‐kDa CDPK in a Western blot, indicating that the 62‐kDa CDPK is identical to DtCPK1. There was no change in the intensity of these bands after hypoosmotic shock, implying that the cellular level of the enzyme protein is not associated with hypoosmotic shock. These results indicate that CDPK is activated only by the increase in cytosolic‐free Ca2+ concentration in vivo.
PRODUCTION OF 7‐DEOXY‐OKADAIC ACID BY A NEW CALEDONIAN STRAIN OF PROROCENTRUM LIMA (DINOPHYCEAE)
Authors: Holmes Michael James , Lee Fu Chin , Khoo Hong Woo , Teo Serena Lay Ming
Published: March 2003

7‐Deoxy‐okadaic acid and okadaic acid were identified as the major diarrhetic shellfish poisoning (DSP) toxins produced by a New Caledonian strain of Prorocentrum lima Ehrenberg. Dinophysistoxin‐1 was not produced by this strain. The cellular concentrations of 7‐deoxy‐okadaic acid were about one tenth that of okadaic acid and were maximal (∼1.4 pg·cell−1) during the stationary growth phase of batch culture. Autolytic hydrolysis of cell extracts did not increase the concentrations of 7‐deoxy‐okadaic acid, whereas okadaic acid production increased more than 4‐fold, indicating that 7‐deoxy‐okadaic acid, unlike okadaic acid, is not directly derived from large sulfated precursors. 7‐Deoxy‐okadaic acid could be detected by liquid chromatography‐selected reaction monitoring mass spectrometry, HPLC‐fluorescence detection after derivatization with 9‐anthryldiazomethane (ADAM), and inhibition of protein phosphatases. The solvent washes currently used for solid‐phase clean‐up of ADAM‐derivatized DSP samples elute derivatized 7‐deoxy‐okadaic acid, indicating that the current sample clean‐up protocol for HPLC‐fluorescence detection would miss any contamination by this toxin.
A SINGLE‐CELL IMMUNOASSAY FOR PHOSPHATE STRESS IN THE DINOFLAGELLATE PROROCENTRUM MINIMUM (DINOPHYCEAE)
Authors: Dyhrman Sonya T. , Palenik Brian
Published: March 2003

Current techniques for studying phytoplankton physiology in the field, such as measurements of biochemical activities, nutrient addition bioassays, and determination of photosynthetic efficiency, are useful for assessing the physiology of the bulk community but suffer from a lack of specificity. This would be improved by the development of single‐cell methods for monitoring in situ physiology. Here we develop and test an antibody‐based assay for identifying phosphate stress in the model dinoflagellate Prorocentrum minimum (Pavillard) Schiller. Antiserum was raised against a cell‐surface alkaline phosphatase purified from P. minimum. Western screening indicated that the antiserum reacted with phosphate‐stressed cells but not nitrate‐stressed or phosphate‐replete cells in culture. Immunodepletion confirmed the identification of this protein as an alkaline phosphatase. Based on Western blots, the antiserum appeared to be specific for phosphate‐regulated proteins in P. minimum because there is no discernible cross‐reaction with closely related P. micans. A whole‐cell immunofluorescence assay was used to identify phosphate stress in field populations of P. minimum from Narragansett Bay, Rhode Island. The percentage of labeled P. minimum cells in this environment during the summer of 1998 decreased through time as the inorganic phosphate concentration increased. The percentage of antibody‐labeled cells significantly correlated with the percentage of ELF‐97‐labeled cells determined as another single‐cell assay of phosphate stress. This is the first antibody‐based method developed for monitoring cell‐specific physiology in a dinoflagellate, and the method described here may serve as a model for developing similar tools in other species of phytoplankton.
CLONAL PROPAGATION OF LAMINARIA DIGITATA (PHAEOPHYCEAE) SPOROPHYTES THROUGH A DIPLOID CELL‐FILAMENT SUSPENSION
Authors: Asensi Aldo , Gall Erwan Ar , Marie Dominique , Billot Claire , Dion Patrick , Kloareg Bernard
Published: March 2003

In vitro cultures of Laminaria digitata (Hudson) Lamouroux stipe medullary explants (Laminariales, Phaeophyceae) gave rise to friable morula‐like masses of pigmented cells. Upon subculture under continuous white light, they grew out as filaments, which tended to dissociate into spherical isolated cells, leading to the establishment of a suspended cell‐filament culture. Depending on culture conditions, this cell‐filament suspension underwent various forms of growth, including regeneration of morphologically normal sporophytes, and this developmental pathway was stimulated by blue light. Genotyping with nine polymorphic microsatellite markers indicated that the regenerated sporophytes and the cell‐filament suspension shared the same genotype. As assessed by flow cytometric analysis of isolated nuclei, the cell‐filament suspension exhibited a 2C nuclear DNA content, whereas the regenerated sporophytes displayed a 4C level. Chromosome counting, however, showed that both the mother suspension and the regenerated sporophytes were diploid, suggesting the involvement of polyteny in the regeneration process.
STRUCTURE‐ACTIVITY RELATIONSHIPS OF OLIGOAGAR ELICITORS TOWARD GRACILARIA CONFERTA (RHODOPHYTA)
Authors: Weinberger Florian , Richard Christophe , Kloareg Bernard , Kashman Yoel , Hoppe Hans‐Georg , Friedlander Michael
Published: March 2003

Agar oligosaccharides in the neoagarobiose series were prepared by partial enzyme hydrolysis, separated on Biogel P2 and P4, and analyzed by high‐performance anion exchange chromatography with pulsed amperometric detection, yielding neoagarosaccharide fractions with a disaccharide repetition degree ranging from 1 (neoagarobiose) to more than 8 (neoagarohexadecaose). These fractions were analyzed for their biological activity toward the marine red alga Gracilaria conferta (Schousboe ex Montagne) J. et G. Feldmann in terms of increase of oxygen consumption, release of hydrogen peroxide, elimination of epiphytic bacteria, and induction of thallus tip bleaching. The structure–activity and dose–response relationships of neoagarosaccharides were very similar in the respiratory and oxidative burst responses and in their bactericidal properties, with neoagarosaccharides consisting of 6 to 8 disaccharide repeating units being the most active. All these responses were competitively inhibited by the reduced form of neoagarohexaose, neoagarohexaitol. In contrast, the tip‐bleaching response was light dependent, required much higher concentrations of neoagarosaccharides, and was not inhibited by neoagarohexaitol, suggesting that it is an unspecific oxidative stress reaction. Putative structural effects on the recognition of endogenous agar‐oligosaccharide elicitors by G. conferta are discussed.
Recirculating Culture for Chondracanthus Exasperatus
Authors: Waaland J. R.
Published: March 2003

The red alga Chondracanthus exasperatus is a source of the phycocolloid carrageenan as well as an ingredient referred to as ‘intralamellar gel’ in a recently developed cosmetic formula (US Patent 6136 329). The high value of the cosmetic product has sparked renewed interest in cultivation of this species. Previous cultivation methods for this species include open water culture on nets and immersed cultivation in tanks supplied with flow‐through pumped seawater. The installation of a high capacity seawater supply, pumping and drain system is a major cost for flow through systems. Recirculating or re‐use seawater systems that minimize seawater turnover may offer significant cost savings over single‐pass, flow through seawater systems. In this research several options for minimizing seawater use have been tested: recirculating batch culture in which nutrient replenished (carbon dioxide and mineral nutrients) natural or artificial seawater is used with minimal turnover and spray culture in which plants are suspended in air saturated with nutrient replenished natural or artificial seawater medium. Small volume (<2 L), single‐plant bioreactors and larger multiplant, 20, 80 and 320 L (sea water volume) immersion and spray systems have been developed and tested. Results from these systems will be presented. Research supported by Washington Sea Grant, Washington Biotechnology Center and Soliv International Corporation.
Digital Algae: A Boon to Research and Teaching
Authors: Waters D. A. , Ciugulea I. I. , Chapman R. L.
Published: March 2003

As part of a larger coastal ecology project, we have initiated a web‐accessible, digitized phytoplankton image and taxonomy database of algae collected in a coastal wetland south of New Orleans, Louisiana. Examining phytoplankton dynamics is a large component of the project, titled ‘Pulses—The Importance of Pulsed Physical Events for Watershed Sustainability in Coastal Louisiana’ (a joint NSF/EPA/USDA Water and Watershed program). A total of 168 species of algae from 76 genera in 8 phyla have been identified from the phytoplankton samples, and 130 high‐resolution (300 dpi) digital images taken. These taxonomic identification data are included in a database with collection information (i.e. location, date). Ecological data (i.e. turbidity, salinity, and nutrients such as nitrate and nitrite, ammonium, phosphorous, and silica) will be added to the database. Having this information available on the web is an important resource for continued research in coastal Louisiana and perhaps other regions with similar ecosystems and hydrology. The database can also be a useful tool for teaching high school and college students. Microscopic phytoplankton are notoriously difficult to identify, and the images can be used in conjunction with keys to help students confirm their algal determinations. Students would also be able to see the main features of different groups of algae and learn some ecological aspects of the wetland habitat where they were collected. Please visit the web site at chapmanlab.lsu.edu/digitalalgae. This project was supported in part by a grant from the Office of Sea Grant Development at LSU.
Phylogenetic Analyses of Nuclear 18S rRNA Gene Sequences Indicate That the Mastophoroideae (Corallinales, Rhodophyta) is a Polyphyletic Taxon
Authors: Gabel J. , Bailey J. C. , Freshwater D. W.
Published: March 2003

Nuclear small subunit ribosomal RNA (18S rRNA) gene sequences were determined for six species representing three genera classified within the Mastophoroideae and also for two species of Amphiroa (Lithophylloideae). These data were combined with previously published 18S rRNA sequences for 37 other coralline species and analyzed to: (1) determine the phylogenetic position of the Mastophoroideae within the Corallinales; and (2) examine relationships among Hydrolithon, Metamastophora, Neogoniolithon, and Spongites. Trees derived from parsimony and maximum likelihood analyses of these data indicate that the Mastophoroideae is not monophyletic. Instead, our data suggest that group is polyphyletic and includes species belonging to three (or more) distinct evolutionary lineages. The nongeniculate genus Neogoniolithon is resolved as sister to the geniculate subfamily Corallinoideae. Hydrolithon is resolved as sister to the geniculate genus Metagoniolithon, an Australian endemic. In turn, Spongites is positioned at the base of a clade including Hydrolithon/Metagoniolithon as well as species classified in the Lithophylloideae. Finally, Metamastophora is placed in a well supported, but isolated, position as sister to all other taxa bearing uniporate tetrasporangial conceptacles. Our results imply that some reproductive and vegetative characters among the suite of features used to delimit the Mastophoroideae were acquired independently and are not homologous. Significantly, our results suggest that genicula are nonhomologous structures that evolved independently in four separate coralline taxa and from four nongeniculate ancestors belonging to distinct evolutionary lineages. On the basis of our findings Porolithon pachydermum is transferred to Hydrolithon as H. pachydermum (Foslie).
Cell Signaling in the Chemoaccumulation Response of the Colonial Green Alga Astrephomene Gubernaculifera
Authors: Hoops H. J. , Gifford S. M.
Published: March 2003

A. gubernaculifera can grow on acetate even in the dark. Interestingly, it displays a well‐developed chemoaccumulation response to added acetate. We suggest that this chemoaccumulation results from a receptor‐based signaling pathway because the alga responds to the structurally similar molecule propionate even though the latter compound cannot support growth. Based on suggestions about chemotactic signaling pathways in other eukaryotes and postulated phototactic response of some algae, we hypothesized that the signaling pathway involves heterotrimeric G‐proteins. The effectiveness of the chemoresponse was determined by measuring the diameter of the chemoaccumulation cloud after addition of 10 mL aliquots of media containing acetate to colonies swimming in media without acetate. Neomycin, which inhibits the G‐protein dependent activity of phospholipase C, completely inhibited chemoaccumulation at 100 mM, and markedly reduced the density of the accumulation response at 10 mM with no obvious changes in general colonial motility. EGTA, a calcium chelator, abolished the chemoresponse. Mastoporan, a G‐protein activator, caused accumulation even in the absence of acetate. These results support the hypothesis that chemoaccumulation in A. gubernaculifera uses a G‐protein mediated, calcium‐dependent, cell‐signaling pathway.
Desmids and Dinoflagellates of Ecuador
Authors: Carty S. , Hall J. D.
Published: March 2003

The freshwater flora of Ecuador is poorly known. This report provides preliminary information about the freshwater Pyrrhophyta and two families in the Chlorophyta. There has been some work on diatoms but other groups remain unstudied. In June 2001, samples were collected as whole water or by using a 10‐mm plankton net from 52 locations in the interior (Amazonian) and Andean regions and examined within hours using a Swift field microscope. Nine additional samples from Ecuador have been provided by Dr Miriam Kannan. Amazonian sites consisted of oxbow lakes along the Rio Shiripuno, and small ponds and lakes along the road from the river to Coca. Andean sites were principally in the Cajas National Park near Cuenca. Genera in the Closteriaceae include Closterium, Gonatozygon, Spinoclosterium, and Penium. Desmidiaceae include Arthrodesmus, Bambusina, Cosmarium, Desmidium, Euastrum, Hyalotheca, Micrasterias, Pleurotaenium, Spondylosum, Staurastrum, Staurodesmus, Triploceras, and Xanthidium. Pyrrhophyta include Ceratium, Gymnodinium, Peridinium, Sphaerodinium, and Woloszynskia.
Actin Phylogeny in the Charophyta
Authors: Lewandowski J. D. , Delwiche C. F.
Published: March 2003

Photosynthetic green plants, the Viridiplantae, are composed of two distinct lineages, the Chlorophyta and Charophyta. The Chlorophyta include the Chlorophyceae, Trebouxiophyceae, Ulvophyceae and most prasinophytes. The Charophyta include the Mesostigmatales, the traditional charophycean green algal orders Chlorokybales, Klebsormidiales, Zygnematales, Coleochaetales and Charales, and land plants, referred to here as Embryophyceae. The Embryophyceae are embedded within the paraphyletic charophycean green algae, so land plants are, therefore best considered a specialized group of green algae adapted to terrestrial life. Due to the close evolutionary relationship between green algae and Embryophyceae, characterizing the early evolution and diversification of land plants depends on understanding phylogenetic relationships among the less extensively studied green algal members of the Charophyta. Relationships within the Charophyta have previously been based on morphology and inferred through phylogenetic analyses of molecular data that include ribosomal DNA and several genes from the chloroplast and mitochondrial genomes. To this point, however, few phylogenetic analyses of nuclear, protein‐coding genes have been conducted. We are attempting to isolate and sequence actin‐coding regions from representative members of the Charophyta. Actin is a highly conserved protein that is ubiquitous among eukaryotes; these features make actin an ideal subject for comparative sequence analysis. A major component of the cytoskeleton, actin plays a number of important roles in plant cell processes such as cell division and cytoplasmic streaming. Hence, in addition to being potentially useful for resolving organismal relationships, the evolution of the actin protein itself is intrinsic to the study of morphological evolution and development within green plants.
Phormidium Retzii (Oscillatoriales): Genotypic Variation and Phenotypic Plasticity
Authors: Casamatta D. A. , Vis M. L. , Sheath R. G.
Published: March 2003

Phormidium retzii is one of the most commonly encountered lotic taxa in North America and has been recorded from a wide range of habitats worldwide. The genetic variability of this cosmopolitan, freshwater cyanobacterium was assessed using gene sequences and random amplified polymorphic DNA (RAPD) markers. Strains consistent with the morphological species circumscription were utilized from British Columbia, Canada to Rio Claro, Costa Rica, and from Rhode Island to Washington State, USA. In addition, some strains were from geographically close (<25 miles apart) sites. The 16S rRNA gene was sequenced for eight of the 12 strains. Sequence homology ranged from 90.95 to 98.71. The nine RAPD primers utilized yielded a total of 133 distinct bands from the 12 strains. The strains were variously related and showed great variation in pairwise genetic distances (0.23–0.83). Given the lack of sequence similarity, P. retzii as presently circumscribed most likely represents several cryptic species not clearly distinguishable with light microscopy of morphological characters. This conclusion may explain the lack of correlation between geographic proximity and genetic similarity. To assess the level of environmentally induced phenotypic plasticity of this taxon, one strain was subjected to three different current velocity and nutrient regimes (low, medium, and high) employing six stream mesocosms. ANOVAs and Bonferroni multiple comparison tests were performed with cell volumes, ratios of cell length : width and percent cover data. Low nutrient treatments elicited significantly (P < 0.05) greater cell volumes and percent cover than did high treatments. Furthermore, current velocity did not show any significant effect on cell morphology. As such, it appears that a single strain is capable of wide morphological variability in response to some environmental conditions. The results of these two studies have great implications in the utilization of cyanobacterial morphospecies concepts.
Molecular Systematics of the Subaerial Green Algal Family Trentepohliaceae (Chlorophyta; Trentepohliales) Inferred From 18 SSU rDNA Sequences
Authors: Lopez‐Bautista J. M. , Chapman R. L. , Rindi F. , Guiry M.
Published: March 2003

Representatives of the monophyletic Trentepohliales are widely distributed in the tropics, subtropics, and temperate regions worldwide. They grow in soil, or are epilithic, epiphytic or endophytic. The family comprises approximately 70 species placed in at least four genera (Trentepohlia, Cephaleuros, Phycopeltis and Stomatochroon), with Trentepohlia sensu lato (including Printzina and Physolinum) accounting for half of the species in this family. PCR amplification and sequencing of the 18 SSU rDNA of 18 isolates of the Trentepohliaceae were used to assess the monophyly of the genus Cephaleuros and to determine the phylogenetic relationships among species of Trentepohlia sensu lato. Distance, Parsimony, and Maximum Likelihood analyses indicate that Trentepohlia sensu lato is basal and includes two species recently transferred to Phycopeltis (P. umbrina) and Printzina (P. lagenifera). In contrast, Cephaleuros is a derived monophyletic clade. Analysis of isolates of C. virescens, from the USA, Taiwan, and South Africa indicate that this taxon may consist of different species sharing a convergent morphology. The results of this study have implications for the taxonomy of the genera.
The Effects of Thallus Toughness and Nutritive Quality on Palatability of Antarctic Macroalgae
Authors: Peters K. J. , Amsler C. D. , Amsler M. O. , McClintock J. B. , Iken K. B. , Baker W. J.
Published: March 2003

Palatability of macroalgae can be affected by many different factors including thallus toughness, nutritional quality (carbohydrates, lipids, proteins, ash), and the presence of deterrent secondary metabolites. Palatability bioassays were performed using two different antarctic algal grazers (the antarctic rockfish Notothenia coriiceps and the sea star Odontaster validus). These data were then compared to toughness and chemical composition data. Toughness was determined using a penetrometer and a wide range of thallus toughness was observed in individuals of differing species as well as of the same species. Some of the tougher individuals required more than 30 N of force to cut through the thallus while others required less than 1 N to break through. Each algal species is also being tested for percent composition of carbohydrates, lipids, proteins, as well as ash. It is hypothesized that the algal species with greater nutritional quality and/or less thallus toughness are more likely to be acceptable foods to consumers (NSF OPP9814538, OPP9901076).
Effects of Environmental Parameters on the Growth Characteristics of Symbiodinium SPP. Isolated from Corals
Authors: Rogers J. E. , Davis R. H. , Oliver L. M.
Published: March 2003

Symbiodinium spp. were isolated from Porites porites (JR02F2 and RD03), Montipora capitata (JR12A7), Madracis mirabolis (RD02), Montastrea faveolata (RD04), Pocillopora damicornis (JR13E1), and an unknown coral (RD01). Growth rates and the distribution between motile gymnodinoid cells and sessile coccoid cells were determined in 200 µL cultures in 96‐well dilution plates. Clones of each isolate were maintained in L1 medium (prepared with 34 ppt sterile Gulf of Mexico water), at 26 °C with illumination provided at 100–150 mE/m2/s PAR (400–700 nm) during a 10 : 14 (light : dark) photoperiod. Under these conditions, generation times of nearly once per 24 h were observed for clones, JR02F2, RD01 and RD02, in log growth. Clone RD04 had a generation time of approximately 5 days. The fastest growing clones produced the highest percentage of motile cells (>90) during the daylight portion of the diurnal cycle. Growth characteristics of selected clones were examined over a range of salinities, temperatures and PAR intensities. Salinities ranging from 25 to 45 ppt had little if any affect on growth rate. At salinities less than 25 ppt significant decreases in growth were generally observed; no growth was common at 5 and 10 ppt. In most cases inhibitory effects of temperature were observed at temperatures greater than 29 °C. For example, generation times for JR02F2 were slightly greater at 29 °C than 24 °C, but maximal growth rates were reduced approximately 50–90% at temperatures of 32 and 34 °C, respectively. The most sensitive clone, RD04, stopped dividing after two divisions at 29 °C. The growth rate of JR02F2 and RD01 reached a maximum at PAR levels greater than 100 mE/m2/s and remained within a range of 0.75–0.85 divisions/day up to 390 mE/m2/s.
Phylogeny of Klebsormidium (Kelbsormidiales; Charophyta) Based on rbcL, atpB, coxIII and nad5 Sequence Data
Authors: Snyder S. W. , Karol K. G. , Delwiche C. F.
Published: March 2003

The charophycean order Klebsormidiales consists of two unbranched filamentous lineages, the fresh water Entransia and the semiterrestrial Klebsormidium. Molecular data have supported the close relationship Klebsormidiales have with land plants. A monograph exists for the European species of Klebsormidium; this monograph provides a cladistic analysis of morphological characteristics for eight Klebsormidium species, but a species level molecular phylogenetic analysis has not yet been performed for the group. We have obtained 50 strains of Klebsormidium, representing 11 morphological species, both from nature and from culture collections. Phylogenetic analyses using rbcL, atpB, coxIII and nad5 gene sequence data from these strains and 40 outgroup sequences suggest that several traditional Klebsormidium species may not be monophyletic.
The Effects of Biogenically Active Compounds on Cyclotella Meneghiniana (Bacillariophyta)
Authors: Tedrow O. , Julius M. L. , Schoenfuss H. L.
Published: March 2003

Biogenically active compounds have been discovered in many surface water samples in Europe and North America. Wastewater effluent is identified as a major source of contamination and found to revert much of the metabolic products of these biologically active compounds back to their original form. This presentation explains methodology for determining the effects of these contaminants through a newly developed bioassay, examining the physiological response of a diatom to these compounds. Diatoms represent an important aspect of the primary production community. They are a desirable food source over other members of the primary production community through storage of photosynthetically produced sugars in the form of lipids rather than starch. Therefore, members of higher trophic levels selectively feed on diatoms when present with other members of the primary production community. This study examines the effects of select biogenically active compounds on the gross morphology and physiological development of the diatom species Cyclotella meneghiniana. Clearly, unicellular protists such as diatoms are not susceptible to these contaminants in a manner directly analogous to that expressed in vertebrates. However, many of these compounds are lipophilic making them particularly effective in entering the diatom cell membrane. Comparing cell density, lipid composition, fatty acid concentrations, and the electron microscope ultra‐structure in control and exposed cultures achieve this study's experimental objectives. This diatom was selected because it commonly occurs in most freshwater environments and has been the subject of other toxicological studies. An adequate literature base also exists for evaluating results of this experiment. The species grows rapidly and is easy to maintain in culture. The use of a phytoplankton species as a test organism complements other investigations involving vertebrate models at the apex of the trophic hierarchy by considering effects at the base of the food web.
Systemic Lupus Erythematosus Presenting as Subacute Delirium in an 82‐Year‐Old Woman
Authors: Heckman George A. , Papaioannou Alexandra , Adachi Jonathan D. , Denburg Judah A.
Published: March 2003

OBJECTIVES: To describe an older patient with delirium attributed to systemic lupus erythematosus (SLE) and to review the literature on neuropsychiatric manifestations of SLE in older people.

DESIGN: Case report and literature review. MEDLINE search using terms systemic lupus erythematosus, neurologic, psychiatric, neuropsychiatric, autoantibodies (antinuclear antibody (ANA), antiphospholipid, anticardiolipin, anti‐double stranded deoxyribonucleic acid (anti‐dsDNA), anti‐Smith), and elderly. Additional articles obtained from hand‐searched references and through experts.

SETTING: Hospital (case report).

PARTICIPANTS: Case report and literature cases.

MEASUREMENTS: None.

RESULTS: SLE is increasingly diagnosed in older adults. Onset is insidious and diagnosis is delayed because of a different clinical spectrum and immunological profile than in younger adults. Autoantibodies have an important role in the pathogenesis of neuropsychiatric manifestations, while vasculitis is less common. Aggressive immunosuppressive therapy is typically indicated, although recent case reports suggest that lower doses may suffice. The American College of Rheumatology 1982 revised criteria may be inadequate to diagnose neuropsychiatric lupus in older persons.

CONCLUSION: Neuropsychiatric symptoms can be prominent in older people, presenting features of SLE. This case illustrates the lowest dose of corticosteroids shown to be effective in an older patient with delirium due to SLE.
Lipoprotein Metabolism in Japanese Centenarians: Effects of Apolipoprotein E Polymorphism and Nutritional Status
Authors: Arai Yasumichi , Hirose Nobuyoshi , Nakazawa Susumu , Yamamura Ken , Shimizu Ken‐ichirou , Takayama Michiyo , Ebihara Yoshinori , Osono Yasunori , Homma Satoki
Published: March 2003

OBJECTIVES: To assess the complex interaction of apolipoprotein (apo) E polymorphisms and environmental factors on lipoprotein profile in centenarians.

DESIGN: Cross‐sectional analysis.

SETTING: Tokyo metropolitan area.

PARTICIPANTS: Seventy‐five centenarians and 73 healthy older volunteers (mean age 63.1 ± 10.0) living in the Tokyo metropolitan area.

MEASUREMENTS: Plasma lipids and lipoproteins, cholesteryl ester transfer protein mass, apo E phenotype, body mass index, nutritional indices (serum albumin, prealbumin, transferrin), dietary intake, inflammation markers (C‐reactive protein (CRP), interleukin‐6 (IL‐6)), activities of daily living, and cognitive function.

RESULTS: In comparison with older people, the centenarians had low concentrations of total and low‐density lipoprotein cholesterol (LDL‐C) and a relative predominance of high‐density lipoprotein 2 cholesterol. No environmental factor, except the number of apo E ε2 alleles, was a significant determinant of LDL‐C and apo B, suggesting that the low apo B–containing lipoprotein in centenarians may be attributable to a genetic cause. Centenarians had elevated levels of lipoprotein (a) and decreased high‐density lipoprotein cholesterol (HDL‐C), which seem to be an unfavorable lipoprotein profile. Lower levels of HDL‐C in the centenarians were associated with decreased serum albumin, elevated CRP and IL‐6 levels, and cognitive impairment, suggesting that HDL‐C could be a sensitive marker for frailty and comorbidity in the oldest old.

CONCLUSIONS: Low levels of apo B–containing lipoproteins attributable to a genetic cause may be advantageous for longevity. Lipoprotein profiles in centenarians were consistently related to the subjects' nutritional status, inflammation markers, and apo E polymorphisms. The results provide evidence for the importance of maintaining nutritional status in the very old.