bluuebunny/crossref_metadata_2025 huggingface dataset:
MORPHOLOGY AND CHEMICAL COMPOSITION OF A NATURAL POPULATION OF AN ICE‐ASSOCIATED ANTARCTIC DIATOM NAVICULA GLACIEI1
Authors: Whitaker Terence M. , Richardson Michael G.
Published: August 2007

During winter (1973), a very pure natural population of the diatom Navicula glaciei Van Heurck occurred in dense concentrations (up to 244 mg·m−2 chlorophyll a) in the sea ice at Signy Island, South Orkneys, Antarctica. Samples of algal material were collected for subsequent chemical analysis. The diatom had a composition of 33.77% ash, 21.81% lipid, 25.38% crude, protein, 19.04% crude carbohydrate and an intact calorific value of 15.384 KJ·g−1. Carbon, hydrogen, nitrogen and phosphorus formed 34, 5.3, 4.1 and 0.52% dry wt respectively. The material was analysed for the trace elements Na, K, Fe, Ca, Mg, Al, Zn, Cu, Pb, Mn, 137Cs. Fatty acid composition was dominated by 16:0 palmitic acid (20.46%), 16:1 palmitoleic acid (32.86%), and 20:5 docosahexaenoic acid (19.33%). To supplement a very scanty original description, a full taxonomic description is given in the text.
ECOLOGY AND DEVELOPMENTAL MORPHOLOGY OF MALE PLANTS OF CHONDRUS CRISPUS (GIGARTINALES, RHODOPHYTA)1
Authors: Tveter‐Gallagher Eleanor , Mathieson Arthur C. , Cheney Donald P.
Published: August 2007

The ecology and developmental morphology of the male plants of Chondrus crispus Stackhouse from New England and the Canadian Maritime Provinces are described. The period of maturation and release of spermatia varies spatially; however, the peak discharge generally occurs over a broad period during the summer or fall. Male plants may exhibit comparable abundances to female plants, particularly during periods of maximum spermatial discharge. At maturity, the spermatangial sorus appears as a pink band on dark red terminal branchlets; following spermatial discharge, the sorus becomes white in color. The developmental morphology of spermatia is described from electron microscopic observations.
THE CONTRIBUTION OF ORGANIC SOLUTES TO OSMOTIC BALANCE IN SOME GREEN AND EUSTIGMATOPHYTE ALGAE1
Authors: Brown Lewis M. , Hellebust Johan A.
Published: August 2007

Sorbitol and proline accumulate to osmotically significant concentrations inStichococcus bacillarisNägeli,Stichococcus chloranthusKrüger andKlebsormidium marinum(Deason) Silva, Mattox & Blackwell. The extent of osmotic balance by these and other organic solutes depends on the isolate for these three species of essentially non‐vacuolate algae. Sucrose, proline and sorbitol accumulate in the lichen algaHyalococcus dermatocarponisWarén, but concentrations on an osmotic basis are low. Sucrose and glutamic acid are significant solutes in the likely non‐vacuolateK. flaccidum(Braun) Silva, Mattox & Blackwell. A similar set of solutes accumulates to an osmotically significant level inUlothrix fimbriataBold, a highly vacuolate alga. Two small eustigmatophycean algae (strains WHOI GSB‐Sticho and WHOI Car‐A) and one small chlorophyte (strain UWASH 20‐2‐2) accumulate organic solutes to a moderate degree during salinity stress; mannitol and proline in the eustigmatophytes and proline in the chlorophyte. The highly vacuolate seaweedEnteromorpha intestinalis(L.) Link accumulates sucrose, but at low levels. Osmotic balance in these algae may also include other solutes, compartmentation (especially in vacuolated forms), or other factors. The role of organic solutes in osmotic balance is variable, and depends on details of physiology and ultrastructure.
PHOTOSYNTHESIS AND TRANSLOCATION STUDIES OF LAURENCIA SPECTABILIS AND ITS SYMBIONT JANCZEWSKIA GARDNERI (RHODOPHYCEAE)1,2
Authors: Court Gary J.
Published: August 2007

The symbiotic association between the supposed parasite Janczewskia gardneri Setchell & Guernsey and its host Laurencia spectabilis Postels & Ruprecht was investigated. Mature plants of J. gardneri were pigmented, contained “typical” red algal chloroplasts when viewed by electron microscopy, and were capable of photosynthesis. Both J. gardneri and L. spectabilis incorporated 14C‐label from NaH14CO3 into similar compounds, including sugars (floridoside, isofloridoside, galactose, glucose) and amino acids (alanine, aspartic acid, glutamic acid, glycine, serine). Translocation of 14C‐labeled photosynthetic products between mature J. gardneri and its host did not occur. This research suggests that mature individuals of J. gardneri are obligate epiphytes.
MICROARCHITECTURE AND ENVELOPE DEVELOPMENT INDYSMORPHOCOCCUS GLOBOSUS(PHACOTACEAE, CHLOROPHYCEAE)1
Authors: Porcella Russell A. , Walne Patricia L.
Published: August 2007

The ultrastructure and development of the envelope (lorica) ofDysmorphococcus globosusBold & Starr are described. This is the first detailed characterization of the envelope of a member of the Phacotaceae. The general ultrastructure and cellular organization of the protoplast are similar to that reported for other volvocalean algae. Transmission electron microscopy (TEM) showed the granular and fibrous components of the immature envelope, the sequential deposition of a mineralized layer, and the presence of perforations in the mineralized layer. Iron is incorporated in the mineralized envelope with55Fe labeling. Experiments with59Fe showed an 86% uptake of available iron by cells in culture, with the label localized to the envelope and envelope‐associated mucilage. Envelope formation is the result of the following phenomena: i) secretion of an immature envelope consisting of an outer fibrous layer and an inner granular layer; ii) sequential precipitation of a mineralized component in the inner layer, during which time pores are formed as part of the developmental process; iii) exudation of mucilaginous materials through those pores; iv) localized secretion and subsequent retention of the secretory product giving rise to the pebbled nature of the envelope surface. In living cells, the envelope surface is coated with mucilaginous secretory products that obscure the pores, which were previously reported to be lacking in this species. Results of acetolysis on aplanospores suggest the presence of a sporopollenin inD. globosus.
ß CARBOXYLATION ENZYMES IN MARINE PHYTOPLANKTON AND ISOLATION AND PURIFICATION OF PYRUVATE CARBOXYLASE FROMAMPHIDINIUM CARTERAE(DINOPHYCEAE)1
Authors: Appleby Geoffrey , Colbeck Jill , Holdsworth Eric S. , Wadman Hugh
Published: August 2007

The diatoms,Phaeodactylum tricornutumBohlin,Cylindrotheca closteriumvar.californica(Meres.) Reim. & Lewin,Thalassiosira pseudonanaHasle & Heimdal and the prymnesiophytePavlova lutheri(Droop), Green, have been shown to contain phosphoenolpyruvate carboxykinase E.C.4.1.1.49. Another diatomChaetoceros calcitrans(Paulsen) Takano, the chlorophyteDunaliella tertiolectaButcher, a rhodophytePorphyridium cruentumNaegeli and the cyanophyteAnabaena cylindricaLemmermann, all possessed phosphoenolpyruvate carboxylases E.G.4.1.1.31, which were stimulated by Mn ions and inhibited by malate and aspartate. Two dinoflagellates,Amphidinium carteraeHulbert andGymnodiniumsp., were shown to contain pyruvate carboxylase E.G.6.4.1.1., not previously reported in plants or marine algae. Pyruvate carboxylase was isolated and purified and found to contain biotin and it was inhibited by avidin and could be distinguished from the other two enzymes by complete inhibition by 5 mM Mn ions. The β carboxylating enzymes account for the anaplerotic formation of amino acids and intermediates of the tricarboxylic acid cycle formed during short‐term fixation of CO2.
BEHAVIOR OF CHLOROPLAST ER DURING CHLOROPLAST DIVISION IN OLISTHODISCUS LUTEUS (CHRYSOPHYCEAE)1
Authors: Magnussen Charlotte , Gibbs Sarah P.
Published: August 2007

During chloroplast division in Olisthodiscus luteus Carter, the envelope of chloroplast ER may infold either in synchrony with the chloroplast envelope or lag markedly behind the chloroplast envelope giving two different patterns of division. In the first type of division the chloroplast ER infolds in parallel with the chloroplast envelope as the plastid pinches in two. In the second more common type of division, the chloroplast envelope infolds, meets and fuses before the chloroplast ER begins to infold thus producing two plastids in a single sac of chloroplast ER. Separation of these plastids is accomplished by the subsequent infolding of the chloroplast ER.
INSECTICIDAL ACTIVITY OF GONYAULAX (DINOPHYCEAE) CELL POWDERS AND SAXITOXIN TO THE GERMAN COCKROACH1
Authors: Demons Gary P. , Pham Dien V. , Pinion Jack P.
Published: August 2007

Crude cell powders prepared from unialgal cultures of Gonyaulax monilata Howell, and G. tamarensis Lebour and saxitoxin were found to be insecticidal against the German cockroach Blatella germanica L., yielding respective LD50 values of 194, 12.50 and 0.7 μg/g insect body weight. Although mice appear more sensitive to saxitoxin than German cockroaches, the insect's small mass and simple rearing requirements favor it as a bioassay organism in analytical situations of limited toxin quantities.
ULTRASTRUCTURE OF THE INFECTION CYCLE OF CYANOPHAGE SM‐2 IN SYNECHOCOCCUS ELONGATUS (CYANOPHYCEAE)1
Authors: Leach Jan E. , Lee Kit W. , Benson Randall L. , Martin Eugene L.
Published: August 2007

Transmission electron microscopy was used to examine the ultrastructure aspects of cyanophage SM‐2 replication in its host Synechococcus elongatus Naegeli UTEX 563. Filled virion heads were observed 10 h after infection, correlating well with the 6–8 h eclipse period for the virus. As the infection cycle proceeded from 10–50 h, additional virion heads accumulated at either end of the nucleoplasm. Of the several cyanophage that lyse unicellular bluegreen algae, this is unique to the SM‐2 system. The surrounding photosynthetic lamellae remained intact throughout the infection cycle. The nucleic acid composition of SM‐2 was determined as DNA.
ULTRASTRUCTURAL STUDIES ONSPHAEROPLEA ANNULINA(CHLOROPHYCEAE). VEGETATIVE STRUCTURE AND MITOSIS1
Authors: Cáceres Eduardo J. , Robinson David G.
Published: August 2007

The ultrastructure of the taxonomically disputed filamentous green algaSphaeroplea annulina(Roth) Agardh has been investigated. The filament is a linear coenobium, the individual coenocytes of which are separated by remnants of cytoplasm termed “plugs.” Vegetative growth is coupled with a form of asexual reproduction in which multinucleate autospores are formed but not liberated. Mitosis is of the semi‐open and centric type. A complete disintegration of the nucleolus in metaphase is not seen. A typical phycoplast to which the centriole pairs migrated at the end of telophase was present. Cytokinesis was not coupled with mitosis. These observations rule out possible affinities with the orders Siphonales (sensu lato) and Cladophorales, and, apart from similarities to the filamentous (uninucleate)Microspora,the Ulotrichales as well. Certain similarities with coenocytic chlorococcalean algae occur, but this investigation supports the concept of a separate order: the Sphaeropleales.
EFFECTS OF HYDROXAMATE SIDEROPHORES (STRONG Fe (III) CHELATORS) ON THE GROWTH OF ALGAE1
Authors: Bailey Kevin M. , Taub Frieda B.
Published: August 2007

Varying concentrations of Fe were tested with three hydroxamate siderophores to demonstrate the interactions affecting growth of Chlamydomonas reinhardtii and Chlorella vulgaris. Schizokinen was purified from the excretions of the blue‐green alga Anabaena sp. grown in low‐Fe medium. Chlamydomonas reinhardtii was inhibited by schizokinen when in molar excess of the Fe concentration; the inhibition was overcome with excess Fe. The growth of C. vulgaris was not affected by this chelator. Results with desferrioxamine were similar. A weaker chelator, rhodorulic acid, did not inhibit the growth of either alga. Low concentrations of the chelators may stimulate algal growth when Fe precipitates are hydrolyzed. Since different algae respond differently to the presence of the chelators, the observed interactions could be important in determining competitive relationships when Fe is limiting. If an alga can excrete a strong chelating agent, as does Anabaena, algae lacking the ability to compete with the chelator may not grow.
ANATOMY AND ALGAL‐FUNGAL INTERACTIONS IN THE LICHENUSNEA CAVERNOSA1
Authors: Malachowski James A. , Baker Karen K. , Hooper Gary R.
Published: August 2007

Interactions between fungal and algal components ofUsnea cavernosaTuck, were demonstrated with transmission and scanning electron microscopy. Cells were observed in very close associations, and both intrawall and intracellular haustoria were evident. In addition, a previously unreported type of interaction was discovered which consisted of an extracellular hyphal sheath with distinctive protuberances which penetrated into the algal cell wall. Internal environmental factors which may bear on the types of cellular interactions were evaluated by dividing the lichen thalius into three artificial regions using spatial and temporal criteria. Fungal hyphae in the various internal anatomical zones (e.g., cortex, medulla, central cord) demonstrated differences in cell wall structure and extracellular material produced.
PHOSPHATE UPTAKE BY SYNECHOCOCCUS LEOPOLIENSIS (CYANOPHYCEAE): ENHANCEMENT BY CALCIUM ION1
Authors: Rigby Cynthia H. , Craig Susan R. , Budd Kenneth
Published: August 2007

The influence of metallic, cations (added at 10 μM‐1 mM) on the uptake of orthophosphate from 0.2–10 μM solution by Synechococcus leopoliensis (Racib.) Komarek was investigated. All cations tested except Mg2+ and Zn2+ stimulated phosphate uptake. The most pronounced stimulation of phosphate uptake was caused by Ca2+·Ca2+ markedly decreased the half‐saturation concentration for orthophosphate uptake, apparently by acting upon the metabolic processes of phosphate transport into the cell. Phosphate did not influence Ca2+ fluxes across the cell‐surface.
STRUCTURE AND PHYCOBILIPROTEIN COMPOSITION OF PHYCOBILISOMES FROM GRIFFITHSIA PACIFICA (RHODOPHYCEAE)1
Authors: Gantt Elisabeth , Lipschultz Claudia A.
Published: August 2007

Phycobilisomes in Griffithsia pacifica are closely spaced on the thylakoid membrane. By negative staining, attached and isolated phycobilisomes have been shown to have a block shaped appearance. They are 63 nm long, 38 nm high, and 38 nm wide, making them the largest thus far reported. Isolated phycobilisomes, shown to be functionally intact by their 675 nm fluorescence emission (excitation 545 nm) were stable for more than a day. Phycobiliproteins from dissociated phycobilisomes, separated on sucrose gradients and by polyacrylamide electrophoresis, yielded large (R‐) and small (r‐) molecular weight species of phycoerythrin (ca. 4:1 respectively) constituting 89% of the phycobiliprotein content, with R‐phycocyanin 8%, and allophycocyanin 3% accounting for the rest. Phycobilisomes of Griffithsia pacifica and Porphyridium purpureum (Bory) Drew and Ross (P. cruentum) are structurally very similar with phycoerythrin being on the outside and surrounding a core of R‐phycocyanin and allophycocyanin.
GROWTH RATES OF PSEUDOPEDINELLA PYRIFORME (CHRYSOPHYCEAE) IN RESPONSE TO 75 COMBINATIONS OF LIGHT, TEMPERATURE AND SALINITY1
Authors: Ostroff Cynthia R. , Karlander Edward P. , Van Valkenburg Shirley D.
Published: August 2007

Clonal cultures were established of single cells of Pseudopedinella pyriforme Carter isolated from the Chesapeake Bay. Axenic cultures were incubated at 5, 10 and 15 C; in 2 1/2, 5, 7 1/2, 10 and 15‰; and at 143, 285, 428, 571 and 714 μW/cm2 white light. Maintainable growth rates were calculated from absorbance readings taken for 3 to 5 days from acclimated cultures. The maximum number of doublings per day was 0.9 at 2 1/2‰ salinity, 571 μW/ cm2 and 15 C. A salinity of 5 ‰ produced the fastest growth at most light intensities up to 428μW/cm2 and temperatures of 5, 10 and 15 C.
ENVIRONMENTAL CONTROL OF PITHOPHORA OEDOGONIA (CHLOROPHYCEAE) AKINETE GERMINATION1
Authors: Spencer David F. , Volpp Ted R. , Lembi Carole A.
Published: August 2007

Abundance of Pithophora oedogonia akinetes displayed seasonal changes, being greatest in winter and lowest in summer. Akinete abundance showed significant (P < 0.001) negative correlations with photoperiod(r = ‐0.53) and water temperature (r= ‐0.75) during the period February 1978 through June 1979. Experiments in which akinete germination was studied in response to manipulations of nutrients (NO3‐N and PO4‐P), photoperiod and temperature indicated that temperature was the primary factor regulating the timing of the vernal flush of akinete germination observed in Surrey Lake.
COMPARATIVE PHYSIOLOGICAL STUDY OF MARINE DIATOMS AND DINOFLAGELLATES IN RELATION TO IRRADIANCE AND CELL SIZE. II. RELATIONSHIP BETWEEN PHOTOSYNTHESIS, GROWTH, AND CARBON/CHLOROPHYLL a RATIO1,2
Authors: Chan Augustine T.
Published: August 2007

Photosynthetic rates, growth rates, cell carbon, cell protein, and chlorophyll a content of two diatom and two dinoflagellate species were measured. The microalgae were chosen to have one small and one large species from each phylogenetic group; the two size categories differed from each other by 1.5 orders of magnitude in terms of cell carbon or cell protein. The cultures for the experiments were grown under continuous light at an irradiance high enough for the light‐saturation of growth for all four species. The four species were found to have similar maximum photosynthetic rates per unit chlorophyll a. The diatom species showed lower carbon/chlorophyll a ratios and higher photosynthetic rates per unit carbon than the dinoflagellates. The higher growth rates of the diatoms were shown to be related to their higher photosynthetic rates per unit carbon. The ecological significance of the physiological difference between these two groups of microalgae is discussed.
CALCIFICATION BY COCCOLITHOPHORIDS: EFFECTS OF pH AND Sr1
Authors: Sikes C. Steven , Wilbur Karl M.
Published: August 2007

Cells of Coccolithus huxleyi which fail to deposit CaCO3 and form coccoliths often occur as unwanted components in cultures used for studies of calcification. Non‐calcified cells generally cannot be made to recalcify, but they can be removed from cultures by treatment at elevated pH or by a method based on faster sinking of calcified cells. Lowering the concentrations of nitrate, phosphate, or trace metals in the medium did not restore calcifying ability of non‐calcified cells. However, addition of strontium did promote recalcification of decalcified Cricosphaera carterae grown under calcium limitation. Strontium seemed to promote coccolith attachment to cells rather than to affect calcium uptake or coccolith formation itself.
DISTRIBUTION AND PHYSIOLOGICAL DETERMINANTS OF BLUE‐GREEN ALGAL NITROGEN FIXATION ALONG A THERMOGRADIENT1
Authors: Wickstrom Conrad E.
Published: August 2007

The capacity of thermal algal‐bacterial mats to fix nitrogen (N2) was examined in an alkaline thermal stream, Rabbit Creek, of Yellowstone National Park. Nitrogenase activity and nitrogen‐fixation rates of mat cores placed in serum bottles and incubated in situ were estimated by the acetylene‐reduction technique. Active nitrogenase was not detected at 60 or 65 C in either the blue‐green algal or bacterial undermat components of the mats. Acetylene was reduced by all mats ≤55 C along the thermogradient; mean fixation estimates for the mats ranged from 7 to 5,028 nmoles N2 fixed · mg Chl a−1· hr−1. Maximum fixation occurred at 35 C in the stream; statistical comparison of mean rates ordered the thermogradient mats according to estimated activities: 35 > 40 > 30 > 50 ≥ 55 ≥ 45 C. Mats (≤40 C) dominated by species of Calothrix accounted for ca. 97% of the total nitrogen fixation observed in the stream; the remaining activity was associated with mats containing Mastigocladus laminosus Cohn. Light intensity significantly affected fixation rates of the Calothrix mats which responded in a linear fashion from 9–100% full sunlight (ca. 1,900 μEin · m−2· sec−1). Calothrix mats from 30 and 40 C had maximum nitrogenase activity at their growth temperature suggesting that nitrogen fixation along the thermogradient was optimally adapted to in situ temperatures.
TAXONOMIC SIGNIFICANCE OF NUCLEUS‐MICROBODY ASSOCIATIONS, SEGREGATED NUCLEOLI AND OTHER NUCLEAR FEATURES IN SIPHONOUS GREEN ALGAE1
Authors: Roth William C. , Friedmann E. Imre
Published: August 2007

On the basis of fine‐structural features of nuclei the “true” siphonous green algae (Eusiphoniidae) are divided into three groups. In theCodiumgroup nuclei are generally similar to those in most other algae. ThePenicillusgroup is characterized by the association of microbodies with nuclei. In theAvrainvilleagroup nucleoli are segregated into a granular and a fibrillar component. This condition, known as macrosegregation, persists throughout the vegetative phase of the life history and may indicate a peculiar ribosomal RNA cycle.

ThePenicillusgroup corresponds to the order Caulerpales Feldmann.AvrainvilleaandCladocephalusprobably constitute a new order.

Blastophysa,although having a type of segregated nucleoli, is probably more closely related to Siphonocladales than to any order in Eusiphoniidae.
OBSERVATIONS ON THE PECULIAR DIURNAL MIGRATION OF A RED TIDE DINOPHYCEAE IN TROPICAL SHALLOW WATERS1
Authors: Horstmann Ulrich
Published: August 2007

The dinoflagellate Peridinium cf. quinquecorne Abé forms red tide‐like blooms in eutrophic shallow waters in the Philippines. The organism moves into a distinct near‐surface layer when intensive solar radiation occurs, but only during the incoming tide. Shortly before high tide, regardless of light levels, the dinoflagellates seem to disappear. Simple experiments show that once intensive radiation has been reduced Peridinium quinquecorne moves out of the water column and attaches itself to solid objects away from the light. The morphology of the organism, especially as related to attachment, was studied through SEM. Its high swimming velocity and the reaction to radiation and tidal changes are described. The possibility that, superimposed on its reaction to light, this dinoflagellate may follow intrinsic tide‐dependent oscillations is discussed.
TRACHELOMONAS HISPIDA VAR. CORONATA (EUGLENOPHYCEAE). I. ULTRASTRUCTURE OF CYTOSKELETAL AND FLAGELLAR SYSTEMS1,2
Authors: West Larry K. , Walne Patricia L. , Rosowski James R.
Published: August 2007

Trachelomonas hispida var. coronata Lemm. has a fibrous, mucilaginous, ovoid, mineralized envelope (lorica), the ornamentation and coloration of which are capricious in culture. Cells exhibit a radial distribution of most organelles: (i) A cortical endoplasmic reticulum, (ii) parietal chloroplasts, and (iii) a median vacuolar region surrounded by several Golgi bodies and diverse vesicles. Associated with the emergent flagellum is a “paraflagellar complex” that consists of dense globules, cross‐striated ribbon‐like structures, a paraflagellar body, and an array of parallel striated filaments. The stigma consists of a single layer of pigmented granules that partially surrounds the canal/reservoir transition zone where microtubular bands intersect. A microtubular cytoskeleton consists of pellicular microtubules, peri‐canal microtubules, stigma‐associated microtubules and para‐reservoir microtubules. The thickenings on the posterior, concave margins of the pellicular strips suggest that this pellicle is of intermediate complexity between those of Euglena spirogyra (Ehrenb. and Trachelomonas volvocina (Ehrenb.).
ULTRASTRUCTURE OF CELL DIVISION AND REPRODUCTIVE DIFFERENTIATION OF MALE PLANTS IN THE FLORIDEOPHYCEAE (RHODOPHYTA): CELL DIVISION IN POLYSIPHONIA1
Authors: Scott Joe , Cynthia Bosco , Schornstein Kathleen , Thomas Jewel
Published: August 2007

Cell division in the marine red algae Polysiphonia harveyi Bailey and P. denudata (Dillwyn) Kutzing was studied with the electron microscope. Cells comprising the compact spermatangial branches of male plants were used exclusively because of their small size, large numbers and the ease with which the division planes can be predetermined. Some features characterizing mitosis in Polysiphonia confirm earlier electron microscope observations in Membranoptera, the only other florideophycean algae in which mitosis has been studied in detail. Common to both genera are a closed, fenestrated spindle, perinuclear endoplasmic reticulum, a typical metaphase plate arrangement of chromosomes, conspicuous, layered kinetochores, chromosomal and non‐chromosomal microtubules, and nucleus associated organelles (NAOs) known as polar rings (PRs) located singly in large ribosome‐free zones of exclusion at division poles in late prophase. However, other features, unreported in Membranoptera, were observed consistently in Polysiphonia. These include the presence of PR pairs in interphase‐early prophase cells, the attachment of PRs to the nuclear envelope during all mitotic stages, the migration of a single PR to establish the division axis, a prominent, nuclear envelope protrusion (NEP) at both division poles at late prophase, the prometaphase splitting of PRs into proximal and distal portions, and the reformation of post‐mitotic nuclei by the separation of an elongated interzonal nuclear midpiece at telophase. During cytokinesis, cleavage furrows impinge upon a central vacuolar region located between the two nuclei and eventually pit connections are formed in a manner basically similar to that reported for other red algae. Diagrammatic sequences of proposed PR behavior during mitosis are presented which can account for events known to occur during cell division in Polysiphonia. Mitosis is compared with that reported in several other lower plants and it is suggested that features of cell division are useful criteria to aid in the assessment of phylogenetic relationships of red algae.
THE GLYCEROL PERMEABILITY OF THE PLASMALEMMA OF THE HALOTOLERANT GREEN ALGADUNALIELLA PARVA(VOLVOCALES)1
Authors: Enhuber Gerhard , Gimmler Hartmut
Published: August 2007

The glycerol permeability of the plasmalemma of the green algaDunaliella parvaLerche was investigated by efflux studies with labelled glycerol, by enzymatic determination of glycerol leakage, and the determination of the reflection coefficient from osmotically induced volume changes (zero flow method).

All results indicate that the plasmalemma ofD. parvadoes not exhibit a special low permeability towards glycerol as would be expected from a glycerol accumulating alga. Rather, significant amounts of glycerol diffuse continuously into the medium following the glycerol concentration gradient between the cells and the medium. Efflux rates vary between 0.1 and 2 μmoles glycerol·mg−1chlorophyll·h−1depending on the external NaCl concentration. After one day up to 25% of the total glycerol of the algal suspension was found in the medium. Within 10 days this value can increase to 60%, depending on the growth constant of the culture. The reflection coefficient σ was determined to be 0.87, the permeability coefficient 2800×10−11m·sec−1.

To maintain a proper endogenous glycerol level corresponding to the external osmotic pressure, glycerol efflux inD. parvahas to be balanced by a continuous synthesis of glycerol.D. parvafollows the strategy of “glycerol efflux tolerance” instead of “glycerol efflux avoidance”. The alga has to pay the energetic costs of this strategy of tolerance.
PILINIA EARLEAE N. SP. (CHLOROPHYCEAE, CHROOLEPIDACEAE) FROM THE FLORIDA WEST COAST1
Authors: Gallagher Susan B. , Humm Harold J.
Published: August 2007

Pilinia earleae n. sp. family Chroolepidaceae, was found in the Tampa Bay area of the Florida west coast in October, 1976, on the tunic of an ascidian, later on dead mollusc shells, a nylon faking line, plastic strips, and as an epiphyte of Gracilaria foliifera, a red alga. It is described on the basis of abundant material from the natural environment and laboratory cultures. The type locality is the southernmost known for the genus in the western North Atlantic.
CULTURING MICROSCOPIC STAGES OF MACROCYSTIS PYRIFERA (PHAEOPHYTA) IN AQUIL, A CHEMICALLY DEFINED MEDIUM1
Authors: Kuwabara James S. , North Wheeler J.
Published: August 2007

Requirements of Macrocystis pyrifera (L.) C. A. Agardh (giant kelp) for nine nutrient elements (N, P, Mn, Fe, Co, Cu, Zn, Mo, I) were established by batch culturing settled spores, through the gametophytic phase, to production of embryonic sporophytes in Aquil, a chemically defined, artificial seawater medium. The ultimately successful medium resulted from ten sequential culturing series, applying an optimization technique to improve each succeeding formulation.
OBSERVATIONS ON MARINE CHAETOPHORACEAE (CHLOROPHYTA). I. SPORANGIAL ONTOGENY IN THE TYPE SPECIES OF ENTOCLADIA AND PHAEOPHILA1
Authors: O'Kelly Charles J. , Yarish Charles
Published: August 2007

A light‐ and electron‐microscope study of sporangial ontogeny in synchronized, mitospore‐producing cultures of Entocladia viridis Reinke, and Phaeophila dendroides (Crouan frat.) Ratters demonstrates that each species has its own characteristic pattern of sporangial development. E. viridis undergoes a sequential cleavage of sporangial mother cell contents with cytokinesis always promptly following mitosis, thus no multinucleate cells are produced. No vesicle surrounds the mature spores, which are released by abrupt rupture of the exit papilla. In P. dendroides a simultaneous cleavage of the sporangial mother cell occurs after a series of synchronous mitoses that result in the production of a multinucleate cell. No vesicle surrounds the mature spores, but a membranous inclusion derived from the central vacuole of the sporangial mother cell lines the sporangial neck at maturity. The inclusion is extruded as a hyaline “plug” through the apex of the sporangial neck some time before release of the spores. This information argues for the retention of the two genera Entocladia and Phaeophila, and suggests another means of deducing higher taxonomic relationships among the marine Chaetophoraceae.
THE CRYPTOMONAD NUCLEOMORPH: ITS ULTRASTRUCTURE AND EVOLUTIONARY SIGNIFICANCE1
Authors: Gillott Marcelle A. , Gibbs Sarah P.
Published: August 2007

The Cryptophyceae are a class of phytoflagellates with affinities to both the red algae and the Chromophyta, by virtue of their possession of both phycobilns and chlorophyllc.Unlike other chromophytes, the periplastidal compartment (the space between the chloroplast envelope and chloroplast ER) is extensive, containing starch grains, ribosomes and a nucleomorph in addition to the vesicles and tubules observed in other chloroplast ER‐containing algae. We have examined the nucleomorph in six species of cryptomonads. There is one nucleomorph per cell except during division, when two are present. The position of the nucleomorph in the interphase cell is species specific: in some species it is embedded in an invagination of the pyrenoid and in others it lies along the inner surface of the chloroplast. The nucleomorph is enclosed by a double membrane; this envelope is interrupted by pores which, in tangential section, appear as elongated slits and have a central dense element. Two types of inclusions have been observed in nucleomorphs: dense globules which are occasionally joined to form ribbons, and a larger fibrillogranular body which resembles a nucleolus. Using a uranyl acetate‐ EDTA‐lead stain, we have tentatively localized nucleic acid within the nucleomorph. The nucleus‐like characteristics of this organelle support the theory that the chloroplast and associated structures bounded by the chloroplast ER represent a reduced eukaryotic endosymbiont. Based on the location of the α‐1,4‐glucan storage product and the presence of phycobilins, we postulate that the endosymbiont was probably a red alga. Other chloroplast ER‐containing algae may have evolved from a cryptomonad‐like ancestor through further reduction of the endosymbiont.
MECHANISMS OF RAPID PHOTOSYNTHETIC ADAPTATION IN NATURAL PHYTOPLANKTON COMMUNITIES. II. CHANGES IN PHOTOCHEMICAL CAPACITY AS MEASURED BY DCMU‐INDUCED CHLOROPHYLL FLUORESCENCE1
Authors: Vincent Warwick F.
Published: August 2007

Photochemical responses to changing light or nutrient conditions were examined in three phytoplankton communities by in vivo chlorophyll fluorescence before (Fa) and after (Fb) the addition of the electron flow inhibitor 3(3,4‐dichlorophenyl)‐1,1‐dimethyl urea. These values were used to calculate an index called “cellular fluorescence capacity” (CFC), defined as (Fb– Fa)/Fb. CFC varied markedly throughout the day and night in the spring community of diatoms and green algae in Lake Taupo, New Zealand. Morning and afternoon maxima were separated by a pronounced depression during the midday peak irradiance. Under continuous low light Taupo plankton demonstrated a circadian rhythm in CFC, but the amplitude of variation was much lower than that recorded under natural or controlled light/dark regimes. In an oligotrophic water body (Wastwater) in the English Lake District a bimodal relationship between CFC and depth was observed when surface features indicated Langmuir circulation. Photochemical capacity measured as CFC could be raised or lowered in samples from this lake by exposure to bright or dim light for 4–8 h. Phytoplankton from a eutrophic lake with a history of nitrogen limitation (Lake Rotorua, New Zealand) responded to nitrogen enrichment after a lag of 4–6 h by an increase in CFC. This was correlated with enhanced rates of carbon fixation and, at longer time intervals, increased growth rates. These CFC data are consistent with the hypothesis that the capacity for non‐cyclic electron transport in natural phytoplankton communities is highly responsive to short‐term changes in light or the availability of nutrients.
BIDDULPHIOID DIATOMS: RESTING SPORES IN ANTARCTIC EUCAMPIA AND ODONTELLA1
Authors: Hoban Michael A. , Fryxell Greta A. , Buck Kurt R.
Published: August 2007

Some antarctic diatoms form resting spores, differing morphologically and probably physiologically from vegetative cells. Differences in the type of resting stages became apparent while examining three species of endemic Antarctic diatoms (Bacillariophyceae, Centrales): Eucampia balaustium Castracane, Odontella weissflogii (Janisch) Grunow, and O. litigiosa (van Heurck) Hoban, comb. nov. Eucampia balaustium usually forms two resting spores per vegetative cell with apparently one residual body and rudimentary valve per resting spore. Odontella weissflogii produces one endogenous resting spore per vegetative cell with at least one, presumably two, residual bodies per resting spore. Through an indeterminate number of divisions, Odontella litigiosa produces a heavily spined morphotype that may function as a resting spore. Odontella litigiosa is transferred from the genus Biddulphia to Odontella C. A. Agardh. The resting spores of all three species have girdle bands. Since resting spores may evolve at different rates than vegetative cells, morphological similarities between the resting spores and the vegetative cells of species in this study and the vegetative cells of species in related families and genera may indicate taxonomic relationships and be of value in formulating phylogenetic schemes.
OBSERVATIONS ON THE SURVIVAL AND GERMINATION OF RESTING SPORES OF THREE CHAETOCEROS (BACILLARIOPHYCEAE) SPECIES1,2
Authors: Hollibaugh J. T. , Seibert D. L. R. , Thomas W. H.
Published: August 2007

Resting spores (hypnospores) of Chaetoceros diadema (Ehrenberg) Gran, Chaetoceros vanheurckii Gran, and Chaetoceros didymus Ehrenberg were collected from a large plastic enclosure moored in Saanich Inlet, B.C., Canada. The effects of combinations of temperature and irradiance on the germination of these resting spores were investigated. Nutrient uptake, carbon fixation, and changes in the photosynthetic capacity of the germinating spores were also examined. Resting spores germinated optimally at combinations of temperature and irradiance similar to those in the environment during sporulation. They did not germinate at irradiances 1.3 μEin m−2 s−1 or temperatures >25.3° C. Nitrate, phosphate and silicate were taken up after the resting spores had germinated and resumed vegetative growth. Chlorophyll a fluorescence in vivo, and the DCMU‐induced increase in in vivo fluorescence also increased after the resting spores had germinated. Resting spores began to fix carbon as soon as they were placed in light. Spores remained viable for at least 645 d. The length of time between first exposure to light and germination did not change during this period; however, the percentage of viable resting spores decreased markedly. None of the Chaetoceros spores germinated after 737 d of storage at 2–4° C in darkness.
PALMELLOPSIS MURALIS SP. NOV. (CHLOROPHYCEAE, TETRASPORALES, PALMELLACEAE)1
Authors: Bold Harold C. , Slocum Robert D. , King Joe M. , MacEntee Frank J.
Published: August 2007

A new member of the chlorophycean, tetrasporalean genus Palmellopsis Korschikov (1953), Palmellopsis muralis Bold and King, is described from limestone in Austin, Texas, U.S.A. Certain details of ultrastructural organization are included.
MORPHOLOGY AND TAXONOMY OF HIMANTOTHALLUS (INCLUDING PHAEOGLOSSUM AND PHYLLOGIGAS), AN ANTARCTIC MEMBER OF THE DESMARESTIALES (PHAEOPHYCEAE)1
Authors: Moe Richard L. , Silva Paul C.
Published: August 2007

The sporophyte of Himantothallus develops according to a closed pattern in which the number and position of the blades is determined by the location of trichothallic meristems in a filamentous germling. Expansion of the miniature juvenile to the massive adult thallus is accomplished by diffuse secondary growth and involves a change from filamentous rhizoids to a hapteroid holdfast, flattening of the stipe, and enormous increases in length, breadth, and thickness of both stipe and blade. The axis usually bears 1–8 lateral blades, often paired, and terminates in a flattened stub. Phaeoglossum is interpreted as a growth form of Himantothallus in which a terminal blade develops to the exclusion of lateral blades, the latter being represented by a single spine. Phyllogigas clearly falls within the morphological spectrum of Himantothallus, the lack of twisting being related to physical factors in the environment.

Sporangia, interspersed with an equal or somewhat larger number of two‐celled paraphyses, are borne in slightly elevated sori scattered over both surfaces of the blade. Zoospore germination was not observed, nor were gametophytes, either in culture or in the field.

Haptera apparently originate from the meristoderm in the lower part of the maturing stipe and lack a filamentous medulla. The mature stipe and the mature blade are anatomically similar, being composed of a superficial meristoderm, a cortex of parenchyma‐like cells, and a filamentous medulla. The meristoderm is usually a single layer of plastid‐containing cells that divide anticlinally to accommodate (or effect) expansion and periclinally to produce cortical tissue inward. Cortical cells are in radial files and increase in diameter towards the interior. They usually are densely packed with physodes. The medulla is uniquely distinguished by the presence of sheathed trumpet hyphae. Cells of the trumpet hyphae have perforate end walls with callose deposits and probably function in conduction as do the sieve filaments in Laminariales. Sheathing cells are filled with plastids. Sheathing filaments form connections among themselves and with nearby unsheathed filaments. The sheathed trumpet hyphae and their matrix of unsheathed filaments form a plexus, which in the mature blade is flattened and may be stripped intact from the other tissues.

Development of the embryonic sporophyte is very similar to that in Desmarestia, as is the anatomy of the adult thallus and the sporangia. From these considerations, Himantothallus is assigned to the Desmarestiaceae (Desmarestiales).
QUANTITATIVE DIFFERENCES BETWEEN BENTHIC ALGAL COMMUNITIES ALONG A DEPTH GRADIENT IN LAKE MICHIGAN1,2
Authors: Stevenson R. Jan , Stoermer Eugene F.
Published: August 2007

This study analyzes the impact of conditions associated with depth upon benthic algal communities in Lake Michigan. Diatom abundance was greater at 9.1 and 14.6 m depths than 6.5, 22.6 and 27.4 m. Shallow (6.5 m), mid‐depth (9.1 and 14.6 m) and deep (22.6 and 27.4 m) zones were distinguishable on the basis of community composition, structure and abundance. Dominance of benthic species, high diversity and low abundance in shallow communities probably resulted from substantial substrate disturbance by wave action in this productive zone. Dominance of benthic species, high diversity and high abundance characterized mid‐depth communities where less wave disturbance enabled algal accumulation. Preponderance of living planktonic taxa, low diversity and low abundance delineated deep communities where planktonic algae accumulated and low light levels reduced growth of benthic species.
MORPHOLOGICAL CHANGES IN TOXIC AND NON‐TOXIC MICROCYSTIS ISOLATES AT DIFFERENT IRRADIANCE LEVELS1
Authors: Krüger G. H. J. , Eloff J. N. , Pretorius J. A.
Published: August 2007

Light intensity (4.5–40.0 μEin m−2 s−1) and culture age had a pronounced effect on cell size and size range of a non‐toxic axenic Microcystis isolate. The rate of cell volume increase (μm3 d−1) was 1.03 × light intensity (μEin m−2 s−1) – 6.49. Average cell volume varied from 33 to 119 μm3, cells at higher light intensities being larger and having a larger size range. The effects on a toxic axenic Microcystis isolate were similar but less pronounced. Average cell volume ranged from 21–74 μm3. In general, cell size and especially size variability appear to be sensitive indicators of physiological state, with cells under stress conditions being larger and associated with a larger size range. The wide range of cell diameters observed at different irradiance levels (3.4–7.2 μm for the non‐toxic and 1.8–6.4 μm for the toxic isolate), makes questionable the use of cell size as a taxonomic character without careful consideration of environmental conditions.
SEASONALITY OF MICROBIAL FOULING ON ASCOPHYLLUM NODOSUM (L.) LEJOL., FUCUS VESICULOSUS L., POLYSIPHONIA LANOSA (L.) TANDY AND CHONDRUS CRISPUS STACKH1
Authors: Sieburth John McN. , Tootle J. Lawton
Published: August 2007

The nature and seasonal extent of microbial fouling on Ascophyllum nodosum (L.) LeJol., Fucus vesiculosus L., Polysiphonia lanosa (L.) Tandy and Chondrus crispus Stackh. were observed by scanning electron microscopy. Bacterial filaments and smaller rod and coccoid forms dominated the fouling communities on all species, with pennate diatoms constituting a minor component in contrast to results with plastic substrates on which pennate diatoms dominated and preceded bacterial colonization. The total percent microbial coverage on the surfaces of all four seaweed species was determined by monthly stereological analyses of representative composite micrographs. These showed a simultaneous decline between April and May which could represent the die‐off of the cold water bacterial flora when water temperature increased past the threshold for obligate psychrophiles. Microbial colonization patterns were directly correlated (P = 0.005) with maximum coverage in April and November–December and reduced levels from May to October. Significant inverse (P < 0.041) correlations between total percent coverage and water temperature indicate distinct seasonal cycles, however, the patterns of dominance by filamentous bacteria and rod and coccoid forms were markedly different. Total coverage patterns of both rhodophytes showed no apparent seasonal cycle and were not related to water temperature. Rod and coccoid bacteria were apparently suppressed year round on P. lanosa relative to the other species. These interspecific differences in seasonal fouling patterns are discussed in light of possible modes of regulation, especially algal antibiosis.
FREEZE‐FRACTURED CHLOROPLAST MEMBRANES OF GONYAULAX POLYEDRA (PYRROPHYTA)1
Authors: Sweeney Beatrice M.
Published: August 2007

The chloroplast membranes of Gonyaulax polyedra Stein were studied in replicas of rapidly frozen and fractured cells. The thylakoid EFs face lacked the large 15–16 nm particles characteristic of plants with the light‐harvesting chlorophyll a/b protein, presumably because the principal light‐harvesting protein of Gonyaulax is the small water‐soluble peridinin‐chlorophyll‐protein and the chlorophyll a/b protein is absent. As in other plants, the EFs thylakoid fracture face carried more particles (4 ×) than EFuface. The PF faces of the thylakoid showed twice as many particles as did the EFs faces. No circadian differences in the number or size of thylakoid membrane particles could be detected. Three membranes comprise the chloroplast envelope in Gonyaulax. They could be clearly differentiated in freeze‐fractured cells. The middle envelope membrane carried many fewer particles on both the EF and PF faces than did the other two envelope membranes. The PF faces of both the outer and inner envelope membranes showed more particles than the EF faces, as do many other membranes which have been examined.
SOURCE‐SINK RELATIONSHIPS IN THE BLADE OF ALARIA ESCULENTA (LAMINARIALES, PHAEOPHYCEAE)1
Authors: Buggeln Richard G.
Published: August 2007

The translocation of 14C‐labelled photoassimilate was studied in blades of the kelp, Alaria esculenta (L.) Grev., which had been surgically modified to produce source and sink regions of various sizes. Thirty cm above the blade base a 2.5 cm dia. section of the blade received a 1 h pulse of H14CO3−. Efflux of 14C‐labelled photoassimilate from this “source disc” was monitored over the next 8 days using a Geiger‐Müller detector probe. Accumulation of 14C‐labelled solutes by a “sink disc” of similar diameter, 20 cm below the source disc, was also monitored. Rate of l4C efflux from the source disc was governed by two factors: (1) total sink size and (2) feed‐back from competing sources. In the latter case, source export was depressed if the portion of the blade, just distal to the source disc, was present. While the initial 14C influx rate into the sink disc was greater when competing sinks were present, the total accumulation of 14C‐photoassimilates was 2–3 times higher in the sink disc when competing sources were not present. Basipetal translocation velocity (1.3–1.7 cm h−1) was unaffected by competing sources and sinks.
BROMINE IN THE CUTICLE OF POLYSIPHONIA NIGRESCENS: LOCALIZATION AND CONTENT1
Authors: Pedersén Marianne E. E. , Roomans Godfried M. , Hofsten Angelica v.
Published: August 2007

The cuticles and chloroplasts of young and old fronds of Polysiphonia nigrescens (Huds.) Grev. were analysed by quantitative X‐ray microanalysis for their content of bromine. Cuticles of old fronds contained 1.7 ± 0.14% bromine while those of young ones contained only 0.94 ± 0.22% bromine. The bromine content of the chloroplasts showed considerable variations between individual chloroplasts, but was found not to increase with age. Young fronds contained four separate layers in the cuticle when observed under the electron microscope. In the old fronds three of these layers disappeared while the remaining one became thick and very electron dense.
HEAVY METALS AND MARINE PHYTOPLANKTON: CORRELATION OF TOXICITY AND SULFHYDRYL‐BINDING1,2
Authors: Fisher Nicholas S. , Jones Gary J.
Published: August 2007

In a study of sublethal effects of metals on growth of the marine diatom Asterionella japonica Cleve, the relative toxicities of Hg, Cu, Zn, Pb, Cd, and Mn are shown to be correlated (r = 0.961) with the solubility products of the corresponding metal sulfides. The results, together with findings elsewhere, suggest a common action for these heavy metals, with toxicity deriving from metal binding to sulfhydryl‐containing compounds in the cell.
The Analytic/Synthetic Distinction
Authors: Russell Gillian
Published: August 2007

The distinction between analytic and synthetic truths has played a major role in the history of philosophy, but it was challenged by Quine and others in the 20th century, and the distinction's coherence and importance is now controversial. This article traces the distinction's historical development and summarises the major arguments against it. Some post‐Quinian accounts are discussed, and the article closes with a list of five challenges which any contemporary account of the distinction ought to meet.