bluuebunny/crossref_metadata_2025 huggingface dataset:
THE EFFECT OF SULFIDE ON THE BLUEGREEN ALGAE OF HOT SPRINGS. I. NEW ZEALAND AND ICELAND1
Authors: Castenholz Richard W.
Published: August 2007

The concentration of soluble sulfide (H2S, HS−, S=)2 in hot springs of New Zealand and Iceland has a “species‐determining” effect which appears to override the effect of all other chemical factors excepting hydrogen ion concentration. The cosmopolitan high‐temperature form (HTF) of Mastigocladus laminosus (Ag.) Cohn appears to be sensitive to concentrations of S= over 0.15 mg·l−1 in New Zealand and 0.25 mg·l−1 in Iceland. It was absent in thermal streams where S= level was high enough to exceed this concentration at a point below its optimal temperature range (i.e., below ca. 50 C). In low or non‐S= springs in these regions this alga formed mats to an upper temperature limit of 63–64 C.

In contrast, one bluegreen alga (Oscillatoria amphigranulata van Goor) occurred abundantly only in moderate to high S= springs of New Zealand; this was a species with an upper temperature limit of about 57 C. Field 14C‐HCO3− incorporation experiments with various levels of added S= confirmed the sensitivity of HTF Mastigocladus and the great tolerance of O. amphigranulata. In the latter, the photosynthetic incorporation of 14C‐HCO3− was sustained or enhanced by the additions of S= in the presence of 5 × 10−5m DCMU, an inhibitor of photoelectron transport on the reducing side of photosystem II. It is possible, but not proven, that S= may act as a photoreductant in this species.
SYNCHRONIZATION OF THE MARINE DINOFLAGELLATEAMPHIDINIUM CARTERIIN DENSE CULTURES1
Authors: Galleron Colette
Published: August 2007

Under improved conditions,Amphidinium carteriHulburt can be obtained as dense cultures (5–9 × 105cells · ml−1) 5 days after inoculation. The possible association of a marine bacterium with the alga is discussed. A method to synchronize this photosynthetic organism is described which is based on the endogenous rhythm of division and the effect of light‐dark alternating periods.
BRACKISH WATER AND FRESHWATER SPECIES OF THE DIATOM GENUS SKELETONEMA. II. SKELETONEMA POTAMOS COMB. NOV.1
Authors: Hasle Grethe R. , Evensen Dale L.
Published: August 2007

Electron microscope investigations of the siliceous frustule show that the diatom described by Hustedt as Stephanodiscus subsalsus (A. Cleve) Hust. is not Skeletonema subsalsum (A. Cleve) Bethge (Melosira subsalsa A. Cleve) but is Microsiphona potamos Weber. This species is so similar to Skeletonema costatum (Grev.) Cleve and Skeletonema subsalsum that the combination Skeletonema potamos (Weber) Hasle is suggested. Present records classify Skeletonema potamos as a freshwater species of lakes and rivers. In Sandusky Bay, Lake Erie (U.S.A.) and in River Wümme, a tributary of the River Weser (Germany) it grows with Skeletonema subsalsum. In nature, and when grown in cultures at a salinity of 0%, the processes are extremely short; when grown at salinities of 2% or more, the processes are much longer.
CHEMICAL ESTIMATIONS OF DNA CHANGES DURING SYNCHRONOUS GROWTH OFEUDORINA ELEGANS(CHLOROPHYCEAE)12
Authors: Lee K. A. , Kemp C. L.
Published: August 2007

Analysis of synchronous populations of Eudorina elegansEhrenberg revealsthat DNA replication occurs coincidentally with the very rapid sequence of cell divisions. The average doubling time for DNA in such synchronous populations is 40 min. The basal amount of DNA/E.eleganscell is estimated to be 0.5 × 10−12g.
SYNCHRONOUS GROWTH IN THE COLONIAL EUDORINA ELEGANS (CHLOROPHYCEAE)1,2
Authors: Kemp C. L. , Lee K. A.
Published: August 2007

Eudorina elegans Ehrenberg has been synchronized by growing the organisms at 32 C in an enriched medium on a 16:8 LD cycle. Nuclear division occurred during the light period and 2–4 h was required, for the population to complete the sequence of 4 or 5 divisions each cell normally undergoes. Each cell division required 2–3 min with ca. 15 min as the intermitotic time. The sequence was repealed, every 24 h as long as synchrony was maintained.
STUDIES ON MARINE PLANKTON DIATOMS. II. RESTING SPORE MORPHOLOGY1
Authors: Hargraves Paul E.
Published: August 2007

A morphological study of resting spores in five marine planktonic diatom species using electron microscopy indicates that Bacteriastrum delicatulum Cleve and Leptocylindrus danicus Cleve spores bear little resemblance, to their vegetative cells. Detonula confervacea (Cleve) Gran and Stephanopyxis turris (Grev. & Arn.) Ralfs spores have several features in common with their vegetative cells, and Rhizosolenia setigera Brightwell lies between the two extremes. The function of resting spores in relation to diatom life cycles is briefly discussed. Spore formation may be a primitive characteristic in the life cycle and may no longer have significant survival value for the species.
VAUCHERIA SYNANDRA (XANTHOPHYCEAE, VAUCHERIALES): FIRST RECORD FOR NORTH AMERICA1
Authors: Pecora Richard A.
Published: August 2007

The brackish water species, Vaucheria synandra Woronin, common to Europe, is reported for the first time in North America from a coastal swamp area in Louisiana. The material from Louisiana is described and pictured, and is compared to other Vaucheria species with androphores.
OOCARDIUM STRATUM A RARE (?) DESMID (CHLOROPHYCEAE)1
Authors: Lois A. Pfiester O.P.
Published: August 2007

The monotypic desmid, Oocardium stratum Nägeli is reported from calcareous stream. Because, of its unusual habitat, it is easily overlooked and is probably more common in occurrence than is reported.
ADAPTIVE PHOTOSYNTHESIS RESPONSES TO TEMPERATURE EXTREMES BY THE THERMOPHILIC CYANOPHYTESYNECHOCOCCUS LIVIDUS1
Authors: Sheridan Richard P. , Ulik Thomas
Published: August 2007

The physiological and biochemical changes associated with and resulting in adaptation to both sub‐ and supra‐optimal temperatures are presented for the thermophilic cyanophyteSynechococcus lividusCopeland. The optimum temperature for growth was 45 C. An increase in the optimum temperature of photosynthesis from 50 to 55 C was shown for cells grown at the supra‐optimum temperature of 57 C; whereas, cells grown at the sub‐optimal temperature of 35 C exhibited a decrease in the optimal temperature from 50 to 45 C for14CO2uptake. These changes in optimal temperatures are interpreted as adaptive. Associated with the 5 C increase in optimal temperature for photosynthesis was an increase in chlorophyll a, plastoquinone A, and activity of ribulose‐1,5‐diphosphate carboxylase (RuDP carboxylase). However, the increase in the temperature optimum for 57 C grown cells was associated with a reduced O2yield correlated with a reduced ferricyanide photoreduction capacity. RuDP carboxylase activity decreased rapidly above 55 C. Therefore reduced rates above 55 C resulted from damage to ferricyanide reducing systems and reduced RuDP‐carboxylase activity, whereas low photosynthesis rates at sub‐optimal temperatures were probably due to rate limiting effect of low temperatures on RuDP carboxylase activity with no evidence of damage to ferricyanide photoreducing systems.
ULTRASTRUCTURE DURING DEVELOPMENT OF THE NUCLEUS OF BATOPHORA OERSTEDII (CHLOROPHYTA; DASYCLADACEAE)1
Authors: Liddle Larry , Berger Sigrid , Schweiger Hans‐Georg
Published: August 2007

The primary nucleus of Batophora oerstedii J. Agardh like that of the related Acetabularia, undergoes a great increase in size throughout vegetative development. Formation of small secondary nuclei represents an irreversible stage in the development of reproductive structures in the gametangia. Changes observed in the course of the life cycle include: i) an increase from 3 to 200 μm diam, of the nucleus; ii) increase in number of nucleoli; iii) development of the perinuclear region; iv) increased pore density in the nuclear membrane; v) development of chromosomes in the nucleoplasm; vi) formation of secondary nuclei; and, vii) division of secondary nuclei.
SUN‐SHADE ECOTYPES OF A BLUEGREEN ALGA IN A HOT SPRING1,2
Authors: Sheridan Richard P.
Published: August 2007

Clone cultures of the thermophilic alga Plectonema notatum Schmidle were established from cells collected from the high and low light intensity regions of the algal mat which developed in Jerry Johnson Hot Spring, Idaho. Clones isolated from cither high, or low light intensify zones were grown at light intensities of 8000 and 400 ft‐c. The existence of specialized and genetically fixed sun or shade ecotypes was evidenced, by the ability of low light intensity clones to synthesize more light harvesting chlorophyll a when grown under low light conditions than the high light clones. High light clones showed light saturation of photosynthesis at higher light intensities with higher carboxylating enzyme activities and less chlorophyll a than low light clones when both were cultured at 8000 ft‐c. These clones displayed infraspecific variation along the light intensity gradient and therefore exist as a mosaic of light, intensity ecotypes.
STUDIES ON MARINE PLANKTON DIATOMS. III. STRUCTURE AND CLASSIFICATION OF GOSSLERIELLA TROPICA1
Authors: Hargraves Paul E.
Published: August 2007

The structure of the tropical oceanic diatom Gossleriella tropica Schütt was examined in the light and electron microscopes. The species is characterized by a primarily poroid valve, surface, it single central labiate process and a unique ring of spines attached to the cingulum. Placement of the genus in the family Rhizosoleniaceae is suggested. Although G. tropica is widely distributed in the world's oceans, it is usually confined to the lower photic zone, salinities of 34.5–35.5% and temperatures of 15–30 C.
THE BIOLOGY OF HARVEYELLA MIRABILIS (CRYPTONEMIALES; RHODOPHYCEAE). V. HOST RESPONSES FO PARASITE INFECTION1,2
Authors: Goff Lynda J.
Published: August 2007

The thallus of Harveyella mirabilis (Reinsch) Schmitz & Reinke is composed of vegetative rhizoidal cells growing intrusively between adjacent cells of the red algal hosts (Odonthalia and Rhodomela) and a protruding reproductive pustule. Although primarily composed of Harveyella cells, host medullary and cortical cells also occur in the emergent pustule. In both tissue regions, Harveyella cells are connected to host cells by secondary pit connections initiated by the host. Direct penetration of host cells by rhizoidal cells of Harveyella occasionally occurs, resulting in host cell death. Degeneration of host medullary cells beneath the pustule may result in a hollow branch and the cortical cells undergo cell division forming a thick palisade layer of randomly associated, photo‐synthetically active cells. It is within these branches that the parasite overwinters vegetatively. Host medullary and cortical cells dispersed in the emergent pustule show few of the degenerative responses noted in host cells adjacent to parasite rhizoidal cells. Rather, host cell division, chloroplast division and photosynthetic assimilation of H14CO−3 all increase. Spherical virus‐like solitary bodies (S‐bodies) occur in all Harveyella cells and in all host cells attached to Harveyella by secondary pit connections. The possibility that these structures may induce the infective response in the host is discussed.
CHLOROPHYLL A:B RATIOS IN SOME SIPHONOUS GREEN ALGAE IN RELATION TO SPECIES AND ENVIRONMENT1
Authors: Keast J. F. , Grant B. R.
Published: August 2007

The chlorophyll a:b ratios measured in several species of Caulerpa and in Bryopsia plumosa (Hudson) C. Ag. gave values close to 2.00 or below. Values obtained for Ulva lactuca L. taken from the same site gave a higher value of 2.44, and the sea‐grass Heterozostera tasmanica (Martens ex Aschers) den Hartog a value of 2.98.

Although there were changes in a:b ratios observed when Caulerpa plants were, stored for up to 10 days in dim light, the values did not suggest that chlorophyll a:b ratios were directly controlled by light intensity. It is conducted that the a:b ratios described in this paper, are a characteristic of the species themselves and are not a result of their growth in extremely shaded situations.
CELLULAR DIFFERENTIATION OF TERMINAL REGIONS OF TRICHOMES OFOSCILLATORIA PRINCEPS(CYANOPHYCEAE)1
Authors: Shukovsky Edward S. , Halfen Lawrence N.
Published: August 2007

The terminal regions ofOscillatoria princepsVaucher display cells which differ from intercalary cells of the same trichome. These end cells have an extensively thickened calyptra replacing normal crosswalls. The thylakoids are extensively disrupted in terminal cells and the cytoplasm displays general disorganization characteristic of necrotic cells. The development of terminal regions occurs within a 5 day period following breakage of the trichome and appears characteristic ofO. princeps.The ecological implications of terminal region differentiation are also considered including reaction to variations in current, temperature and light intensities.
DIATOM MINERALIZATION OK SILICIC ACID. I Si(OH)4 TRANSPORT CHARACTERISTICS IN NAVICULA PELLICULOSA
Authors: Sullivan C. W.
Published: August 2007

Silicic acid transport was studied in the photosynthetic diatom Navicula pelliculosa (Bréb.) Hilse using [68Ge] germanic acid (68Ge(OH)4) as a tracer of silicic acid (Si(OH)4). The initial uptake rate of Si(OH)4 was dependent on cell number, pH, temperature, light and was promoted by certain monovalent cations in the medium. Na+ was more effective than K+, whereas Li+ and NH+4 were ineffective at promoting uptake.

Uncouplers and inhibitors of oxidative phosphorylation and of photophosphorylation reduced uptake by 40–99% of control values. Uptake was also especially sensitive to the sulfhydryl blocking agents at 10−5 M and to the ionophorous compound valinomycin (10−7 M) which inhibited uptake by 82%.

The Si(OH)4 transport system displayed Michaelis‐Menten‐type saturation kinetics with kinetic parameters of KS= 4.4 p. mol Si(OH)4· 1−1, Vmax= 334 pmol Si(OH)4· 106 cells−1· min−1. Calculations of the acid soluble silicic acid pool size based on 60 s uptake at 20 μM Si(OH)4 suggested that intracellular levels of Si could reach 20 mM and as much as 5 mM could exist as free silicic acid, representing maintenance of a 250‐fold concentration gradient compared with the medium.

Efflux from preloaded cells was dependent on temperature and the Si(OH)4 concentration of the external medium. In the presence of 100 μMM “cold” Si(OH)4, approximately 30% of the Si(OH)4 in preloaded cells was exchanged in 20 min.

The initial uptake rate of Si(OH)4 in logarithmic phase cells was constant, but the uptake rate increased in a linear fashion for 6 h in stationary phase cells.

These results suggest that the first step in silica mineralization by diatoms is the active transmembrane transport of Si(OH)4 by an energy dependent, saturable, membrane‐carrier mechanism which requires the monovalent cations Na+ and K+ and is sensitive to sulfhydryl blocking agents. Silicic acid transport activity also appears to be regulated during different growth stages of the diatom.
ANIN SITUSTUDY OF RECRUITMENT, GROWTH AND SURVIVAL OF SUBTIDAL MARINE ALGAE: TECHNIQUES AND PRELIMINARY RESULTS12
Authors: Neushul M. , Foster M. S. , Coon D. A. , Woessner J. W. , Harger B. W. W.
Published: August 2007

Fouling plates (Plexiglas squares and concrete blocks) were bolted in a horizontal position to racks on the ocean floor at a depth of 12 m. Some of these were periodically taken from the sea, subjected to nondestructive microscopic survey in the laboratory, and then replaced. Others were: a) left undisturbed as controls; b) variously caged to exclude larger predatory animals; or, c) had sediment removed from them at intervals. Populations developing on the periodically surveyed plates were similar to those on undisturbed plates. Populations on undisturbed plates were significantly different from those on partially caged plates. The exclusion of large predators by complete caging resulted in highly significantly different communities from those on partially caged plates. Completely caged Communities were composed mainly of worms, barnacles and bryozoans. Summer‐installed plates supported significantly different populations at the end of the experimental period (12 mo) from winter‐installed plates. Plant growth rates were slow, not exceeding 2 cm/mo, and the mortality rates were often high. A few species had high rates of recruitment and survival each month. Most had high recruitment only in the most favorable growth periods and high loss rates. Physical conditions on the sea floor were measured. The methods developed during this study make it possible to quantitatively describe the growth and reproduction of populations of benthic marine algae in the sea.
INTERACTION OF PLECTONEMA BORYANUM (CYANOPHYCEAE) AND THE LPP‐CYANOPHAGES IN CONTINUOUS CULTURE1
Authors: Cannon Robert E. , Shane Miriam S. , Whitaker Janice M.
Published: August 2007

Continuous culture techniques are used to study long‐term population interactions between Plectonema boryanum Gomont, a filamentous bluegreen alga, and the LPP‐viruses which infect it. After LPP‐I (virulent cyanophage) infection of sensitive algae, 3 oscillations occur in cell density with concomitant oscillations in virus titer before final stabilization of both algal and viral concentrations. After LPP‐ID and LPP‐2 (temperate viruses) infection, oscillation in cell density occurred with burst of virus particles. Resistant algae always repopulated the chemostat; lysogeny was not established. The interaction between Plectonema that was resistant to virus infection and the 3 LPP‐cyanophages resulted in rapid elimination of the viruses from the chemostat in the effluent. When lysogenic P. boryanum was tested, a law population of virus was present in the chemostat throughout the incubation period indicative of spontancous induction. Clones of lysogenic algae were isolated.
ISOLATION AND CHARACTERIZATION OF GOLGI APPARATUS FROM EGGS OF FUCUS (PHAEOPHYCEAE)1
Authors: Matthews R. A. , Evans L. V. , Callow Maureen E.
Published: August 2007

A golgi‐rich cell‐free fraction has been obtained from eggs of Fucus serratus L. and characterized by enzyme markers (IDP‐ase and TPP‐ase) and electron microscopy. The results are correlated with cytochemical localization of IDP‐ase and TPP‐ase in situ.
AUTOTROPHIC AND HETEROTROPHIC NUTRITIONAL BUDGET OF SALT MARSH EPIPHYTIC ALGAE1
Authors: Saks Norman M. , Stone Robert J. , Lee John J.
Published: August 2007

This paper addresses the nutrition and relative importance of primary production to heterotrophy of select unicellular green algae and diatoms from the same assemblage. Algal growth responses to nutrient additions varied widely. Such responses included: inhibition and enhancement of growth by amino acid additions: nonstimulation or inhibition by most sugars 10 mM concentration; glucose stimulation of 6 and inhibition of 3 species; fructose inhibition of 6‐ and 3‐ fold stimulation of one species; stimulation of most species by a vitamin mixture, some natural products, metabolite mixtures, etc. Photoassimilation of glucose and aculeate in 8 of 12 species occurred. Nine of 12 species took up only a fraction of the total carbon fixed as organic substrate. Enhancement of photosynthesis by glucose and inhibition by acetate was common. The data suggest that attached littoral and shoal marine algal assemblages may play mixed trophic roles lower levels of the detrital food web.
THE ROLE OF GLUTAMINE SYNTHETASE IN THE INCORPORATION OF AMMONIUM INSKELETONEMA COSTATUM(BACILLARIOPHYCEAE)1
Authors: Falkowski Paul G. , Rivkin Richard B.
Published: August 2007

TheKmfor ammonia for glutamine synthetase and glutamate dehydrogenase was measured in enzyme extracts fromSkeletonema costatum(Grev.) Cleve. At similar physiological pH and temperature the half‐saturation constant for glutamine synthetase was 29 μM, whereas for GDH it was 28mM. On the basis of relative enzymic activity, as well as substrate affinity, it is suggested that glutamine synthetase is the enzyme primarily responsible for the incorporation of ammonium into the amino acid pool, when extracellular nitrogen is at ecological concentrations.
FURTHER EVIDENCE FOR A MEMBRANE‐BOUND ENDOSYMBIONT WITHIN THE DINOFLAGELLATEPERIDINIUM FOLIACEUM1
Authors: Jeffrey S. W. , Vesk Maret
Published: August 2007

The fine structure of the binucleate, fucoxanthin‐containing dinoflagellatePeridinium foliaceum(Stein) Biechler was re‐examined for evidence of an endosymbiout. The eucaryotic nucleus, chloroplasts and associated ribosome‐dense cytoplasm were separated by a single invaginating membrane from the rest of the dinoflagellate cell. The triple membrane‐enclosed eyespot, mesocaryotic nucleus, trichocysts and accumulation bodies resided in the dinoflagellate cytoplasm. These observations suggest thatP. foliaceumcontains a membrane‐bound endosymbiont, similar to that already described for the closely related species.P. balticum(Levander) Lemmermann.
ALGAL SYMBIONT OF A SOFT CORAL1
Authors: Singh A. P. , Mercer E. H.
Published: August 2007

The algal symbiont of the soft coral Sarcothelia edmondsoni (Verrill), is identified as the dinoflagellate Gymnodinium microadriaticum (Freudenthal) Taylor on the basis of its cytology apparent in electron micrographs. The character of the nucleus, peripheral lobed chloroplast with a vase‐shaped pyrenoid body and other inclusions form the basis for identification.
CALCIFICATION IN THE GREEN ALGAHALIMEDA.I. AN ULTRASTRUCTURE STUDY OF THALLUS DEVELOPMENT1
Authors: Borowitzka Michael A. , Larkum Anthony W. D.
Published: August 2007

The ultrastructure of 4 species of the calcareous, siphonaceous algaHalimeda (H. cylindraceaDecaisne,H. discoideaDecaisne,H. macrolobaDecaisne andH. tuna(Ellis & Solander) Lamour) has been studied, and the observed changes during growth and development are related to changes in the degree of calcification. A distinct gradient in the types and quantities of cell organelles exists in a growing apical filament. As these filaments grow, branch, and eventually develop into a mature segment, changes in the organization of organelles such as mitochondria and chloroplasts are observed. Calcification begins when the chloroplasts reach structural maturity and when the peripheral utricles adhere (fuse). This adhesion of the peripheral utricles isolates the intercellular space (ICS) in which calcification occurs from the external seawater. Calcification begins in the outermost (pilose) cell wall layer of the walls facing into the ICS. The cell walls at the thallus exterior undergo extensive changes after utricular fusion; the pilose layer is lost, the cuticles of adjacent utricles fuse forming a ridge at their junction, and multiple cuticles are formed.

The aragonite (CaCO3) crystals which are initially precipitated within the pilose wall layer, rapidly increase in size and number, eventually filling much of the ICS. Only the initial nucleation of aragonite is associated with the pilose wall layer, the later precipitation of aragonite is totally independent of the pilose layer. In older segments secondary deposition of CaCO3also occurs around existing aragonite needles.
DEVELOPMENT OF MUCILAGINOUS SURFACES IN EUGLENOIDS. I. STALK MORPHOLOGY OF COLACIUM MUCRONATUM1
Authors: Rosowski James R. , Willey Ruth L.
Published: August 2007

The envelope and stalk of Colacium mucronatum Bourr. & Chad, were examined in living cells with light microscopy and in fixed preparations with scanning electron microscopy using critically point dried (CPD) and freeze dried (FD) preparations. The envelope of palmelloid cells is formed over the entire cell surface by many individual strands attached at right angles to areas of articulation of the pellicular strips. Strands were observed to anastomose on the posterior tip of otherwise naked cells. Stalks of living cells in India ink preparations had an optically dark inner core with a lighter outer sheath. In FD stalks a definite inner core was not evident, whereas CPD stalks had an outer surface composed of thick strands which may be the collapsed and aggregated strands of the FD stalks. In both there was also an amorphous matrix. The stalk forms from the aggregation of many strands from the anterior cell tip back to a point encompassing the cell surface anterior to a cross section of the tip 9 μm diam. The outer surface of the stalk comes from the pellicular surface joining that area and the core from the cell tip in the area of the canal opening. Any possible participation of the inner canal surface in stalk formation could not be determined because of the great density of the mucilage at the cell‐tip/stalk junction.
PHOTOSYNTHESIS IN THE SNOW: THE ALGACHLAMYDOMONAS NIVALIS(CHLOROPHYCEAE)1
Authors: Mosser J. L. , Mosser A. G. , Brock T. D.
Published: August 2007

Red blooms of snow algae consisting almost exclusively of large spherical red cells ofChlamydomonas nivalis(Bauer) Wille are widespread during the summer in the Beartooth Mountains in Montana and Wyoming. Field studies designed to examine the effects of temperature, light, and water potential on algal activity were performed with natural populations using photosynthetic14C‐HCO3‐ or14CO2incorporation as a measure of activity. The algae photo‐synthesized optimally at 5.4 × 104lx, but were not inhibited by increased light intensity up to 8.6 × 104lx, the maximum observed in the field. Photosynthesis was sensitive to a reduction in water potential, and since low water potentials develop in snow at temperatures below 0 C, it is unlikely that significant algal activity occurs at the sub‐0 temperatures which occur throughout winter. Photosynthesis was much lower following melting of the snow, but this was probably due to decreased diffusion of CO2. The optimal temperatures varied considerably among the different algal populations. Most samples photo‐synthesized optimally at 10 or 20 C but retained substantial activity at temperatures as low as 0 or ‐3 C. Exceptional samples photosynthesized optimally at 0 or ‐3 C. It is proposed that the varied temperature responses reflect the presence of different temperature strains. Taken together, the data suggest that development of the snow algae can occur only during the summer months.
CYTOCHROME c548 IN NOSTOC SP. (CYANOPHYCEAE): AN ELECTRON ACCEPTOR FROM REDUCED NADP IN THE DARK1
Authors: Pulich Warren
Published: August 2007

A c‐type, carbon monoxide‐binding cytochrome was isolated and studied from an endophytic Nostoc sp. Enzymatic transfer of electrons from NADPH to this cytochrome was demonstrated in cell‐free preparations under dark, anaerobic conditions, probably mediated by NADPH‐cytochrome reductase or ferredoxin‐NADP reductase present in the extracts. This cytochrome, with an α‐peak at 548 nm, had physicochemical properties similar to the low potential c‐type cytochrome, cytochrome c549, previously described by other workers from Anacystis nidulans. The participation of such c‐cytochromes in dark electron transport, possibly respiratory, of bluegreen algae is strongly indicated.
AN INVESTIGATION OF THE VERTICAL DISTRIBUTION OF SELECTED BENTHIC MARINE ALGAE WITH A TIDE–SIMULATING APPARATUS1
Authors: Edwards Peter
Published: August 2007

The growth yields of 8 species of red and 4 species of green algae, collected from various vertical levels on the western Atlantic (New Jersey) shore, were investigated in a range of emersion‐submersion regimes in the laboratory. The sinusoidal tide‐simulating apparatus consisted of a plexiglass frame connected by a nylon thread to a rotating wheel, powered by an electric motor geared to make one revolution every 12 h. Inocula of settled spores on glass cover‐glasses were placed at 6 levels on the frame and alternately raised out of, and lowered into, a seawater tank every 6 h with consequent subjection to 0, 18, 37, 58, 79, and 100% submergence regimes per tidal cycle. There was little correlation between the vertical position of a species on the shore in nature and its ability to grow as the percentage submergence per tidal cycle increased. All species tested grew best when continuously submerged, even those that are usually restricted to elevated positions on the shore in nature. The majority grew well in all regimes in which there was some submergence per tidal cycle, except for one sublittoral species (Callithamnion byssoides) whose growth decreased sharply as the percentage exposure to the air was increased.
DIATOM MINERALIZATION OF SILICIC ACID. II. REGULATION OF Si (OH)4 TRANSPORT RATES DURING THE CELL CYCLE OF NAVICULA PELLICULOSA1
Authors: Sullivan C. W.
Published: August 2007

Synchronized populations of Navicula pelliculosa (Bréb.) Hilse show a 10‐fold increase in Si(OH)4 transport rate during traverse through the cell division cycle. The transport activity pattern is similar to a “peak enzyme.” Kinetic analysis showed there was a significant change in Ks values, indicating increased “affinity” for Si(OH)4 as cells neared maximal uptake rates. However, the dramatic changes in transport rate at various cell cycle stages were also reflected by alterations in the Vmax, values of the transport process, suggesting a change in the number of functional transport “sites” in the plasma membrane. Cells in the wall forming stage, arrested from further development by Si(OH)4 deprivation, maintained high transport rates for as long as 7 h. The rates decreased rapidly if protein synthesis were blocked or if Si(OH)4 was added, the latter allowing the cells to traverse the rest of the cycle. The half‐life of the transport activity ranged from 1.0 to 2.2 h when protein synthesis was inhibited at various cell cycle stages and during the natural decline of activity late in the cycle. The transport system appears to be metabolically unstable as is typical for a “peak protein.” The rise in transport rate through the cell cycle did not depend on the presence of Si(OH)4 in the medium; therefore, the transport system does not appear to be induced by its substrate. The rise in transport is also observed in L:D synchronized cells developing in the presence of Si(OH)4; neither does the transport system appear to be derepressed. The transport rate was strongly cell cycle‐stage dependent; the data appeared to fit the “dependent pathway” model proposed by Hart‐well to explain oscillations in enzyme synthesis during the cell cycle.
FACTORS INFLUENCING THE TOXICITY AND ANIMAL SUSCEPTIBILITY OF ANABAENA FLOS‐AQUAE (CYANOPHYTA) BLOOMS1
Authors: Carmichael Wayne W. , Gorham Paul R.
Published: August 2007

Biological factors have been found which can cause variable toxicity of colony and clonal isolates of Anabaena flos‐aquae (Lyngb.) de Bréb. when cultured in the laboratory. These factors help to explain some of the variable toxicity of and animal susceptibility to A. flos‐aquae blooms in nature. Two bacteria in the Enterobacteriaceae isolated from a toxic waterbloom, depressed toxin production in selected bacteria‐free toxic clones of A. flos‐aquae. These toxin‐depressing bacteria decreased culture toxicity 3‐fold from 80 to 240 mg/kg (intra‐peritoneal in male mice). Many colony isolates from a toxic bloom had minimum lethal dosages (LDmin) greater than 240 mg/kg. This was because they were composed of mixtures of toxic and nontoxic filaments. The oral LDmin of the toxin from A. flos‐aquae clonal isolate NRC‐44‐1 varied significantly for 6 different animal species. Using these oral LDmin it is estimated that a surface‐concentrated bloom of toxic A. flos‐aquae, having a biomass density of 20 mg/ml dry weight, would cause death of ducks or calves when 20 ml/kg was consumed whereas a monogastric animal such as a rat would require 80 ml/kg.
CELL DIVISION AND COLONY FORMATION IN THE GREEN ALGACOELASTRUM(CHLOROCOCCALES)1
Authors: Marchant Harvey J.
Published: August 2007

Multinucleate cells ofCoelastrumundergo precisely directed cytokinesis, guided by phycoplast microtubules, to form a number of uninucleate daughter cells which subsequently adhere to form characteristically patterned aggregates. As there is no movement of the daughter cells relative to one another before their adhesion, the disposition of cells in daughter colonies reflects the pattern of cytokinesis of parent cells. Centrioles lie at the poles of the mitotic nuclei which are partially enclosed by a perinuclear envelope of endoplasmic reticulum. The centrioles disappear at the time of cytokinesis of the parental cell and apparently reformde novoonce the daughter cells have acquired a cell wall following their adhesion. The trilaminar layer of cell wall, often termed the pectic layer, does not stain with ruthenium red and resists acetolysis suggesting that it contains sporopollenin rather than pectin.
A STUDY OF IN VITRO ELECTRON TRANSPORT ACTIVITY IN MARINE PHYTOPLANKTON AS A FUNCTION OF TEMPERATURE1
Authors: Ahmed S. I. , Kenner R. A.
Published: August 2007

The in vitro temperature inactivation of the electron transport system (ETS) activity was measured for 11 phytoplankton species. The average inactivation temperature is between 18–23 C, but exceptions with inactivation temperatures as high as 43 C were noted for a tide pool phytoplankton, Dunaliella tertiolecta Butcher. Despite differences in temperatures at which the ETS activity begins to decrease, experimental values for the energies of activation (E) of electron transport are very similar and average ca. 12 kcal/mol. The results show the necessity of applying temperature corrections to in vitro ETS activity measurements when oceanic in situ oxygen consumption is computed from ETS activity measurements. The progress of thermal inactivation of the ETS activity in phytoplankton species studied yields biphasic curves. The biphasic nature of the curves is expressed when using both relatively high and low temperature of inactivation and in more or less heat sensitive species. These curves are described in terms of microsomal and mitochondrial substrate dependence. Based on the obtained temperature response of the ETS activity, the adaption of phytoplankton species to growth temperature is discussed.
PROTEIN AND AMINO ACID COMPOSITION OF THE OBLIGATE HALOPHILE APHANOTHECE HALOPHYTICA (CYANOPHYTA)1
Authors: Tindall Donald R. , Yopp John H. , Schmid Walter E. , Miller Donald M.
Published: August 2007

Total protein was determined for cells of Aphanothece halophytica Fremy harvested during early log, mid‐log and linear growth phases in media containing 1, 2, and 3 M NaCl. Cells grown in medium containing 1 M NaCl showed a progressive increase in protein content up to a maximum of 76% of dry weight (linear phase). Total protein also increased in cells grown in 2 M NaCl. medium (56.5–72.0%). Cells grown in 3 M NaCl medium showed a progressive decrease in total protein (59.9–43%). Although amounts of protein varied, the percentages of the respective amino acids of hydrolyzed bulk protein were consistent to within 1% for linear phase cells grown in 1, 2, and 3 M NaCl cultures. Percentages of acidic amino acids were 2.3–2.6 times greater than those of the basic amino acids. The amino acid composition of phycocyanin was similar to that of bulk protein. Free amino acids varied with both age of the culture and the concentration of NaCl. The high quantity and quality of the protein observed suggest that A. halophytica might be a useful food organism.
POLYMORPHIC BEHAVIOR OF ULVA LACTUCA (CHLOROPHYTA) IN AXENIC CULTURE. I. OCCURRENCE OF ENTEROMORPHA‐LIKE PLANTS IN HAPLOID CLONES1
Authors: Bonneau Edmund R.
Published: August 2007

An isolate of Ulva lactuca L. was brought into axenic culture in both defined synthetic medium and enriched seawater. Haploid clones were established and followed through several generations in both media. Plants possessing distromatic, partially distromatic or completely tubular blades in cross sections, as well as individuals that were completely distromatic in one area of the blade and tubular in another all developed from the same swarmer population. Variations in basal area morphology also occurred. Progeny from swarmers of any of these morphological types showed a similar mixture of morphological variation, indicating non‐mutational variability in phenotypic expression of the blade and basal areas. A mechanism by which such variation may occur without mutation is discussed.
CULTURE AND HYBRIDIZATION STUDIES ONGIGARTINA PAPILLATA(RHODOPHYTA)1
Authors: Polanshek Alan R. , West John A.
Published: August 2007

The foliose red algaGigartina papillata(C. Ag.) J. Ag. was studied in culture to determine its life history and possible relationship to the life history ofPetrocelis middendorffii(Ruprecht) Kjellman. Carpospores cultured from individual female plants gave rise to either crustosePetrocelis‐like plants that reproduced by tetraspores, or to another generation of foliose female (cystocarpic) plants that reproduced by carpospores. Apices cultured from blades of individual field‐collected female plants produced either papillae with many procarps that developed cystocarps only when crossed with male plants, or papillae with few procarps that produced cystocarps in the absence of male plants. The results are interpreted to demonstrate that two types of life history occur inG. papillata:one, a sexual life history involving a crustose tetrasporophyte; the other, a possibly apomictic life history involving only cystocarpic plants. Hybridization experiments demonstrated, thatG. papillatais interfertile withGigartina‐phase gametophytes cultured from tetraspores ofP. middendorffii.Sexual plants of G.papillataare postulated to represent the naturally‐occurring gametophyte ofP. middendorffiiin California. The possible relationships of the sexual and apomictic plants ofG. papillataare discussed.
THE GENUS PLATOMA (GIGARTINALES, RHODOPHYTA) WITH A DESCRIPTION OF P. ABBOTTIANA SP. NOV.1
Authors: Norris James N. , Bucher Katina E.
Published: August 2007

Platoma abbottiana (Gymnophlaeaceae; Gigartinales), a new species of benthic red algae, is described from Isla Mejía and is the second member of this genus reported from the Gulf of California, Mexico. Vegetative anatomy and reproductive details of the carpogonial and auxiliary cell branches of the new species are described and illustrated. Geographical distributions of the seven previously described Platoma species are given. Their distinguishing morphological characteristics are compared to those of the new species. The correct time and place of valid publication of the generic name, Platoma, and some of its binomials are discussed.
TAXONOMIC SIGNIFICANCE OF SECONDARY CAROTENOID FORMATION IN NEOSPONGIOCOCCUM (CHLOROCOCCALES, CHLOROPHYTA)1
Authors: Deason Temd R. , Czygan Franz‐Christian , Soeder Carl J.
Published: August 2007

The pigmentation of 23 species of Neospongiococcum Deason was studied in the stationary phase of nitrogen‐limited cultures on agar with or without glucose or in liquid medium. Fourteen species gradually developed an orange or brown color, and in all, secondary carotenoids were detected by thin‐layer chromatography. Among these, the keto‐carotenoids echinenone, canthaxanthin and esterified astaxanthin were identified, although the last named was not always present. When aging on glucose agar, the remaining nine species developed only a yellow‐green or yellow color and a pronounced tendency to bleach. In these, the aforementioned keto‐carotenoids were lacking, and β‐carotene and lutein lucre dominant. From this study it is not clear whether secondary carotenoid formation is species‐specific in Neospongiococcum.
LAUDERIA ANNULATA—A MARINE CENTRIC DIATOM WITH AN ELONGATE BILOBED NUCLEUS1
Authors: Robert W. Holmes
Published: August 2007

Lauderia annulata Cleve is probably unique among marine centric diatoms in possessing an elongate dumbbell‐shaped nucleus. A lobe at, each end of the nucleus lies adjacent to each valve during interphase and each lobe resembles a typical eucaryotic nucleus. The central portion of the thin strand, which passes through the vacuole connecting the two lobes is Feulgen positive and is nuclear membrane bounded. A group of micro tubules occurs in this strand clustered excentrically between, the nuclear membrane and the tonoplast. Evidence for the coordinated functioning of both nuclear lobes is suggested, by the aggregation of chloroplasts around, both lobes when shade‐adapted cells are exposed, to intense white or blue (400–500 nm) light.
PROBING PHYCOBILISOME STRUCTURE BY IMMUNO‐ELECTRON MICROSCOPY1
Authors: Gantt Elisabeth , Lipschultz Claudia A.
Published: August 2007

By immuno‐electron microscopy it was shown that phycoerythrin is located on the outer surface of the phycobilisome and allophycocyanin is on the inside near the photosynthetic membrane in the red alga Porphyridium purpureum (Bory) Drew & Ross (P. cruentum). These findings are consistent with the idea that the phycobilisome junctions as a light harvesting antenna and energy sink, which directs the energy to chlorophyll in the photosynthetic membrane. A technique was devised in which unfixed phycobilisomes, attached to thylakoid vesicles, were separately reacted with three monospecific antisera (to B‐phycoerythrin, R‐phycocyanin and allophycocyanin) and the reaction products were secondarily marked by reaction with ferritin‐conjugated goat‐antirabbit gamma globulin fraction. This was subsequently followed by glutaraldehyde fixation and staining with phosphotungstic acid. The entire procedure was carried out on an electron microscope grid. The results confirm the previously proposed phycobilisome structural model.
METABOLIC SEGREGATION OF INTRACELLULAR FREE AMINO ACIDS IN PLATYMONAS (CHLOROPHYTA)1
Authors: Wheeler Patricia A. , Stephens Grover C.
Published: August 2007

14C‐amino acids were supplied to Platymonas subcordiformis (Wille) Hazen and the incorporation of radioactivity into protein and other compounds was followed. Alanine was rapidly metabolized by both N‐limited and N‐sufficient cells. Arginine and lysine were metabolized rapidly by N‐limited cells, but were sequestered from metabolism in N‐sufficient cells. This suggests the existence of two functionally distinct pools; a “metabolic” pool that is rapidly metabolized and preferentially used for incorporation into protein, and a “storage” pool rich in basic amino acids that is sequestered from metabolism.
COPPER SORPTION AND RELEASE BY CYCLOTELLA MENEGHINIANA (BACILLARIOPHYCEAE) AND CHLAMYDOMONAS REINHARDTII (CHLOROPHYCEAE)1
Authors: Button Kenneth S. , Hostetter H. P.
Published: August 2007

Initial Cu++ sorption by Cyclotella meneghiniana Kütz. (Cu++‐sensitive) and Chlamydomonas reinhardtii Dangeard (Cu++‐resistant) was rapid in the first 5 min of Cu++ incubation with little sorption after 2 h. On a cell to cell basis, Cyclotella sorbed ca. five times more Cu++ from the medium than Chlamydomonas. In MBL medium with EDTA Cyclotella and Chlamydomonas cells sorbed 21.0 and 4.41 nM Cu++/106 cells respectively in 6 h with 0.3 mg Cu++/l in the medium. Proportionally similar quantities of Cu++ were sorbed when the cells were Cu++ incubated in MBL + citrate or filtered lake water. Cleaned cell walls of Cyclotella sorbed little Cu++ (1.7 nM/106 cells) as compared to living cells (17.5 nM Cu++/106 cells) in 3 h. Therefore, in living Cyclotella most of the Cu++ taken up must be absorbed by the protoplasm or perhaps by the organic layer surrounding the silica wall. Cleaned cell walls of Chlamydomonas sorbed 3.5 nM Cu++/106 cells and living Chlamydomonas cells sorbed 2.6 nM Cu++/106 cells. This indicates that most of the Cu++ sorbed by Chlamydomonas cells remained bound to the cell wall and probably did not readily enter into the protoplasm: When placed in Cu++ free medium after Cu++ incubation, Cyclotella and Chlamydomonas cells released 46 and 59% respectively of the Cu++ sorbed.
ELECTRON MICROSCOPE OBSERVATIONS ON THE INTERACTION OFBDELLOVIBRIO BACTERIOVORUSWITHPHORMIDIUM LURIDUMANDSYNECHOCOCCUSSP. (CYANOPHYCEAE)1
Authors: Burnham Jeffrey C. , Sun Donald
Published: August 2007

The effects ofBdellovibrio bacteriovorus(Stolp & Starr) culture supernatants onPhormidium luridumvar.olivaceaBoresch andSynechococcussp. were examined by transmission electron microscopy. Both normal (nonheat‐treated) and heat‐treated bdellovibrio supernatant caused the formation of intrathylakoidal vesicles inP. luridumin 24–48 h. This vesiculation increased until 96–129 h when theP. luridumshowed loss of the mucopeptide layer in the cell envelope and subsequently lysed. Similar treatment ofSynechococcussp. with the bdellovibrio supernatants showed a different ultrastructural pattern with the apparent dissolution of many of the photosynthetic membranes in the bluegreen cells. Myelin‐like membranous configurations were seen in some of these treated cells. The results suggest that an autolytic mechanism inP. luridumandSynechococcussp. is stimulated by the bdellovibrio secretions.
EFFECTS OF IRON DEFICIENCY ON ISOCHRYSIS GALBANA (CHRYSOPHYCEAE) AND PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1
Authors: Glover Hilary
Published: August 2007

Cultures of Isochrysis galbana Parks and Phaeodactylum tricornutum Bohlin were grown in iron‐limited chemostats. With increasing iron deficiency, photosynthetic rate per cell and assimilation number decreased. The pattern of photosynthesis was also altered; in Fe deficient cells the proportion of 14C fixed in glycine and serine decreased with an accompanying increase into alanine after 3 min assimilation. Although there was no significant effect of Fe deficiency on the proportion of 14C incorporated into total amino acids and amides, the percentage of total 14C fixed in protein increased with increasing Fe deficiency. Cellular levels of chlorophyll a, carotenoids, cytochromes and protein also decreased with increasing Fe deficiency. However, the reduction in chlorophyll a/cell was not as great as that of cytochrorne f1 and Fe deficient cells therefore showed a marked increase in chlorophyll a:cytochrorne f1 ratio.
FINE STRUCTURE OF NAUTOCOCCUS MAMMILATUS (CHLOROCOCCALES, CHLOROPHYCEAE), A COCCOID ALGA WITH TOMENTOSE CELL WALLS1
Authors: Deason Temd R. , Schnepf E.
Published: August 2007

The unusual morphology of the coccoid, neustonic alga Nautococcus mammilatus Korschikov prompted its study with the electron microscope. Ultrastructural features including a fibrous cell wall with definite periodicity and an external tomentum were observed. These and other features of the alga are compared with those of related, species, and the use of cell wall characteristics in taxonomy is discussed.
ELECTRON MICROSCOPE OBSERVATIONS ON THE FLAGELLAR APPARATUS OFBRYOPSIS MAXIMA(CHLOROPHYCEAE)1
Authors: Hori Terumitsu
Published: August 2007

The flagellar apparatus in male gametes of the siphonaceous green alga,Bryopsis maximaOkamura, was studied and compared with that of other green biflagellate cells. The proximal portions of two basal bodies are connected by a single striated proximal band, unique among the biflagellate reproductive cells of green algae studied. Anterior to the flagellar bases is a pair of distal bands different from the single structure in other biflagellate cells. These bands which arise from the distal portion of each basal body, extend upward in the papilla and curve down toward the lower edges of the basal bodies. They seem to have no direct association with each other. Two pairs of distinct flagellar roots, one consisting of 3–5 microtubules and the other of a partially striated fiber of undetermined numbers of microtubules, diverge from the basal body region and extend towards the cell posterior. Their component microtubules are disorganized into single or smaller groups midway over the cell length. The uniqueness of the flagellar apparatus is briefly discussed.