bluuebunny/crossref_metadata_2025 huggingface dataset:
ALGAL EXCRETION AND BACTERIAL ASSIMILATION IN HOT SPRING ALGAL MATS1
Authors: Bauld John , Brock Thomas D.
Published: August 2007

Benthic algal‐bacterial mats are present in the effluents of alkaline hot springs at temperatures between 50 and 73 C. The thin surface layer is composed of the unicellular blue‐green algaSynechococcus lividus. Also present in the surface layer and forming thick, orange mats beneath it, are filamentous, phototrophic, gliding bacteria of the genusChloroflexis, also capable of heterotrophic growth. The very low species diversity and the constancy of the hot spring environment, make these mats a good ecosystem for studying the transfer of nutrients from the algae to the bacteria. To determine whether the alga might supply organic materials to the bacterium, excretion by natural populations ofS. lividuswas studied in the field by means of short‐term radioisotope experiments. Under optimal conditions for photosynthesis, between 3 and 12% of the total14C fixed was excreted as14C‐labeled organic compounds. Variations in cell density at concentrations ofS. lividusapproximating those found in the mat had no effect on the percentage excretion. However, at cell densities below a threshold, level, the percentage excretion increased with diminishing cell density. Except at very low light intensities the percentage of fixed carbon excreted, was very similar for all light intensities tested. Excretion at temperatures approaching the upper limit for growth was not significantly different from the percentage excretion values observed at lower temperatures.14C‐labeled organic compounds excreted during algal photosynthesis could be subsequently assimilated by natural populations of the bacteria present in the mat.
FINE STRUCTURE OF CAPITULAR FILAMENTS IN THE COENOCYTIC GREEN ALGAPENICILLUS1,2,3
Authors: Turner James B. , Friedmann E. Imre
Published: August 2007

Capitular filaments ofPenicillus capitatuscontain a large central vacuole. The parietal cytoplasm is densely packed, devoid of chloroplasts in the growing tip, and becomes convoluted and sponge‐like as extensions of the vacuole penetrate the cytoplasm in mature portions of the filament. Structure of organelles and their distribution in the filament are described. The vacuole contains a variety of inclusions, such as membranous configurations, spherical bodies, electron dense bodies, and calcium oxalate monohydrate crystals, each of the latter surrounded by a chamber associated with microtubules. Endophytic bacteria are present throughout the vacuole and occasionally in the tip cytoplasm. Some vacuolar components ofP. pyriformisare described for comparison.
CONDITIONS OF ILLUMINATION AND ZOOSPOROGENESIS IN KLEBSORMIDIUM FLACCIDUM1
Authors: Cain Jerome R. , Mattox Karl R. , Stewart Kenneth D.
Published: August 2007

The filamentous green alga Klebsormidium flaccidum will produce zoospores when cultured on a diurnal regime of 8‐hr light and 16‐hr dark. Zoosporogenesis is inhibited by interruption of the dark period with light of sufficient intensity and duration. The relationship between intensity and maximum time of interruption before total inhibition of zoosporogenesis is nonlinear.
ENRICHMENT OF SURFACE FRESHWATER MICROLAYERS WITH ALGAE1
Authors: Parker Bruce C. , Hatcher Roger F.
Published: August 2007

Using a variety of techniques for sampling micro‐layers in freshwater environments, the frequent occurrence of significant and striking differences in algal community structure and densities relative to subsurface water is demonstrated.
SOME CHARACTERISTICS OF THE SPERM ATTRACTANT FROMOEDOGONIUM CARDIACUM1
Authors: Machlis Leonard , Hill Gerry G. C. , Steinback Katherine E. , Reed Walfred
Published: August 2007

A bioassay for the sperm attractant fromOedogonium cardiacumwas developed. The attractant was confirmed to be highly water soluble, destroyed by heating to 100 C and by dilute acid or alkali. It was fractionated by gel filtration with the attractant accompanied by yellow pigments. It has it molecular weight between 500 and about 1500, based on gel filtration, ultrafiltration, and dialysis. Freezing changes this to both larger and smaller molecules. It appears to have cationic groups. A paper chromatographic separation was found that divided the pigment into at least 3 major bands, one of which was closely associated with the attractant. An absorption spectrum of this pigment showed 1 peak in the visible spectrum at 417 mμ and 3 well‐defined peaks in the ultraviolet region. The lack of a peak at 280 mμ indicates the attractant is not a polypeptide.
STUDIES ON THE AUTECOLOGY OF THE MARINE DIATOM THALASSIOSIRA NORDENSKIÖLDII CLEVE. 1. THE INFLUENCE OF DAYLENGTH, LIGHT INTENSITY, AND TEMPERATURE ON GROWTH1
Authors: Durbin Edward G.
Published: August 2007

The marine diatom Thalassiosira nordenskiöldii Clave was grown at 48 different combinations of daylength (9:15, 12:12, 15:9 LD), light intensity (0.011, 0.027, 0.066, 0.100 ly/min [g cal/cm2/min]), and temperature (0, 5, 10, 15 C). Growth occurred at all combinations of light and temperature except at 15 C at the highest light level. Maximum growth (K = 1.8 doublings/day) occurred at 10 C under the 15:9 LD cycle. At 15 C the maximum rate was 1.7 doublings/day but occurred at the shortest day‐length (9:15 LD). The maxima at 5 and 0 C were 1.32 and 0.67 doubling/day, respectively.

At 0 C growth was similar over a wide range of light intensities (K = 0.6–0.65), with, maximum growth being attained at a much lower light intensity than at 5 C. Above 5 C there was a decrease in the light intensity at which maximum growth occurred and excessive light became inhibitory to growth. At 15 C the light intensity at which maximum growth occurred was greater with shorter day‐lengths. The temperature optimum was 10 C at 15:9 and 15 C at 9:15 LD.

The chlorophyll a content of the cells was greatest under low light intensities and short daylengths, while temperature had a variable effect.

The response of Thalassiosira in the laboratory contrasts with, its apparent preference for low temperatures in nature (0–5 C). The experiments suggest that the termination of the bloom of Thalassiosira in Narragansett Bay and elsewhere is not solely temperature dependent.
INTERSPECIFIC HYBRIDITY IN THE DESMID GENUS PLEUROTAENIUM1
Authors: Ling H. U. , Tyler P. A.
Published: August 2007

Three desmid taxa, isolated from different parts of Australia, conform to the morphological taxa Pleurotaenium ehrenbergii, P. mamillatum, and P. coronatum. Use of successful zygospore formation between cells of mixed populations as an indication of ability to share a common gene pool shows that all 3 taxa are at least closely related and probably are members of the same biological species. Tentatively, we suggest synonymy of these taxa and urge the adoption of sexual criterion in delimiting desmid species.
NEW RECORDS OF ASCOPHYLLUM NODOSUM (L.) LE JOL. FROM THE WARMER PARTS OF THE ATLANTIC OCEAN1
Authors: John David M.
Published: August 2007

Floating plants of Ascophyllum nodosum (L.) Le Jol. have been found for the first time at 00°47'S, 14°10'W to 01°21'S, 13°32'W. Populations of attached individuals do not occur below 40°N, although previous records of drift plants are known from further south. The plants found near the equator have probably arisen from attached populations in western Europe.
ACETATE METABOLISM BY WHOLE CELLS OF PHAEODACTYLUM TRICORNUTUM BOHLIN12
Authors: Cooksey Keith E.
Published: August 2007

Both morphological forms of Phaeodactylum tricornutum incorporated acetate in the light and in darkness. In the dark, the majority of the acetate was oxidized, probably by the tricarboxylic acid cycle. Although some CO2 was formed from acetate in the light, most acetate carbon was found in the cellular lipids. Acetate incorporation in the light was probably a result of both direct and indirect assimilation. The organism grew poorly on acetate in the light at a very low CO2 tension.
SEXUAL REPRODUCTION IN PANDORINA UNICOCCA1
Authors: Rayburn William R.
Published: August 2007

The effects of nutrients and light on sexual reproduction were investigated in 2 mating pairs of Pandorina unicoca. Strains 101–104 required nitrogen deficiency for sexual differentiation. Sulfur deficiency also appeared to be effective in evoking sexual differentiation. The time required for sexual differentiation of strains 103–104 after removal of KNO3 and MgSO from the medium was 24 hr. Addition of KNO3 and MgSO4 after 24hr did not reverse sexual differentiation. Light was required during the first 10–12 hr. Strains 105–106 did not require a period of sexual differentiation and, exhibited mating activity in the presence of nitrogen and sulfur in the medium. Both mating pairs required light for the mating response and calcium was necessary for zygote formation. The pH range for mating activity was determined.
THE SIGNIFICANCE OF REPRODUCTIVE AND SPORE GERMINATION CHARACTERISTICS TO THE SYSTEMATIC OF THE CORALLINACEAE: NONARTICULATED CORALLINE ALGAE12
Authors: Chihara Mitsuo
Published: August 2007

This paper deals with reproductive and spore germination characteristics to the systematics of the nonarticulated coralline algae. As can the articulated coralline algae, the nonarticulated coralline algae may also he divided into 2 groups on the basis of their yearly reproductive cycles, spore dimensions, and spore germination characteristics: the Lithophyllum group and the Lithothamnium group. These 2 groups are basically identical with the Amphiroa and Corallina groups of the articulated coralline algae, respectively, so far as these 3 characters are concerned. The grouping of these representatives of the Corallinaceae into 2 groups—Amphiroa—Lithophyllum and Corallina–Lithothamnium—coincides with a grouping based on the manner of connection between cells of adjacent filaments.
PHYSIOLOGICAL INVESTIGATIONS ON ALARIA ESCULENTA (L.) GREV. (LAMINARIALES). I. ELONGATION OF THE BLADE1,2,3
Authors: Buggeln Richard G.
Published: August 2007

A seasonal rhythm in blade elongation rate was observed in Alaria esculenta. Maximum (3.0–3.6 cm/week) and minimum (0.5–1.0 cm/week) rates were recorded in June and September, respectively. Translocation of growth‐promoting metabolites occurs within the main blade and between the sporophylls and blade. Bidirectional flow of growth‐promoting metabolities within the stipe was demonstrated. Seasonal effects of nutrients (NO3‐ and PO43‐) and photoperiod on blade elongation were shown in long‐term laboratory experiments. Control of seasonal blade growth by exogenous and endogenous factors is discussed.
TWO SPECIES OF THE CHLOROPHYTE GENUS OSTREOBIUM FROM SKELETONS OF ATLANTIC AND CARIBBEAN REEF CORALS1,2
Authors: Lukas Karen J.
Published: August 2007

Two species of the siphonaceous chlorophyte Ostreobium inhabiting the aragonite skeletons of Atlantic and Caribbean reef corals were studied. Ostreobium quekettii Bornet & Flahault has been previously reported from these locations, but the species is here amended to include filament forms previously described under the name O. reineckei Bornet. Ostreobium constrictum sp. n. is described here for the first time. The 2 sympatric species are distinguished on the basis of filament morphology and chloroplast form.
THE ULTRASTRUCTURE OFDERBESIA TENUISSIMA(DE NOTARIS) CROUAN. I. ORGANIZATION OF THE GAMETOPHYTE PROTOPLAST, GAMETANGIUM, AND GAMETANGIAL PORE1,2,3
Authors: Wheeler Andrew E. , Page Joanna Z.
Published: August 2007

The fine structure of vegetative and reproductive gametophytes ofDerbesiatenuissima is described. Development of the gametangium and release of the gametes progress as follows: (1) In initial stages of gametangium formation, prior to 24 hr before gamete release, there is an accumulation and proliferation of nuclei, chloroplasts, and other organelles. (2) This is followed by separation of the gametangium from the rest of the plant by a gametangial membrane; segregation of organelles into gametes has begun by 12 hr before release and the process is completed by 2.5 hr before release. (3) Enzymatic wall dissolution of the pore area occurs between 2.5 and, 12 hr before normal lights‐on time. (4) The release mechanism appears to be an instantaneous light‐induced increase in lurgor pressure rupturing the weakened pore area, of the wall and causing a forcible expulsion of the gametes. (5) Following release, the pore is sealed by organellar debris and the gametangial membrane. Additional wall layers are presumed to be laid down internal to the plugged pore by the vegetative protoplasm which migrates into the area.
APPLICATION OF GAS‐LIQUID CHROMATOGRAPHY TO STUDY OF THE ENVELOPE LIPIDS OF HETEROCYSTS12
Authors: Lorch Steven K. , Wolk C. Peter
Published: August 2007

Gas‐liquid chromatography of algal extracts provides a sensitive assay for their content of 1‐(O‐α‐d‐glycopyranosyl)‐3, 25‐hexacosanediol, the principal glycolipid from the envelope of heterocysts of Anabaena cylindrica. Different patterns of lipids were found in the heterocysts of 5 species of Anabaena and Nostoc. Lipids with comparable chromatographic properties were detected in Gloeocapsa.
UPTAKE OF ORGANIC, COMPOUNDS BY TWO FACULTATIVELY HETEROTROPHIC MARINE CENTRIC DIATOMS1,2
Authors: White Alan W.
Published: August 2007

Glucose and galactose uptake ability inCyclotella cryptica(clone WT‐1‐8) and glucose uptake ability inCoscinodiscussp. develop rapidly in the dark. Induction of sugar uptake ability in the dark does not require the presence of sugar in the medium. The sugars are taken up by carrier‐mediated systems. InC. crypticaglucose and galactose are probably taken up by the same system. The capacity of glucose uptake in this recently isolated clone ofC. crypticais nearly 5 times that of a previously studied clone (0‐3A). Other organic compounds, which by themselves do not support heterotrophic growth, can be taken up and respired by both diatoms at considerable rates compared, to glucose and galactose. Therefore, in nature, these diatoms may be able to utilize a variety of dissolved organic compounds as sources of intermediary metabolites and as respiratory substrates.
ISOLATION, GROWTH, AND PHYSIOLOGY OF ACIDOPHILIC CHLAMYDOMONADS1,2
Authors: Cassin Patricia Erlbaum
Published: August 2007

A buffered, chelated, defined medium was developed for isolation and growth of acid‐bog flagellates and for physiological studies of bog chlamydomonads.

Hydrogen ion tolerances of Chlamydomonas acidophila, C. sphagnophila 121 A, C. sphagnophila IU293, and, C. reinhardi were determined. Only C. acidophila grew at pH 2.0. It did not grow at pH 7.0 or 8.0 as did the other chlamydomonads tested. Liver fraction “L” and Fe permitted growth of C. acidophila at pH 2.0 equal to control growth at pH 5.0. Neither C. sphagnopliila 121A nor C. reinhardi grew at pH 2.0 with these additions. Hydrogen ion seems to be excluded from the cell interior of acid‐tolerant species. They remained green (ie, pheophytinization did not occur) when cultured below pH 5.0.

C. acidophila grew in the dark with glucose as sole source of carbon and energy. Acetate, glycolate, and glyoxylate were assimilated in the dark if glucose was also present. C. sphagnophila 121A did not grow in the dark on any of the 51 organic carbon compounds tested.

C. acidophila and C. sphagnophila 121A seem promising tools for determining biochemical mechanisms responsible for differences in H+ tolerances. Presumably specialized cell walls or membranes are involved.
A COMPARATIVE STUDY OF CELL DIVISION INTRICHOSARCINA POLYMORPHAANDPSEUDENDOCLONIUM BASILIENSE(CHLOROPHYCEAE)1
Authors: Mattox Karl R. , Stewart Kenneth D.
Published: August 2007

Pseudendoclonium basilienseandTrichosarcina polymorphaare essentially identical with regard to the fine structural details of cell division even though one was previously classified in the Chaetophorales and the other in the Ulvales. Cell division in the 2 genera is also shown to be like that inUlva,as previously suggested might be the case. The combination of mitotic and cytokinetic characteristics common to the 3 genera is distinctive: (1) precocious development of a thick cleavage furrow, (2) centrioles distinctly lateral to polar fenestrae, (3) collapse of the interzonal spindle at telophase, and. (4) a cleavage furrow not associated with microtubules. It is suggested that features of vegetative cell division presently provide the best, characteristics for defining the Ulvaceae and that the use of growth habit should be abandoned. Despite the fact that a phycoplast is not present, in these algae, it is concluded that their affinities lie with genera that do possess a phycoplast.
BENTHIC ALGAE OF SOUTHERN BAFFIN ISLAND. III. EPILITHIC AND EPIPHYTIC COMMUNITIES1
Authors: Moore J. W.
Published: August 2007

Blue‐green algae–mainly Aphanocapsa pulchra (Kz.) Rabh., Oscillatoria tenuis Ag., Schizothrix muelleri Naeg., and Lyngbyn spp.—were predominant, in the epilithic communities of Baffin Island rivers and lakes during 1972, usually accounting for more than 90% by numbers and volume of the total flora. Diatoms were only important early in the growing season (June) with Achnanthes marginulata Grun., A. kriegeri Krasske, and Tabellaria flocculosa (Roth) Kz. being most common. Standing crop in one river increased from near 0 in June to 6.0 × 104 cells/cm2 (2.2 × 108μ3/cm2) in July and back to near 0 again by October. Low levels of nitrate nitrogen probably limited algal numbers, while flooding, light, and grazing by herbivores appeared to have little effect. Changes in algal standing crop in the lakes followed much the same pattern as outlined above. However, the maximum amount of algae was considerably greater than that recorded from the rivers, reflecting the greater availability of nutrients.

Lyngbya nana Tild. was the main algal species attached, to filaments of Mougeotia sp., reaching greatest development (5.0 × 104 filaments/cm2) during September. On the other hand, diatoms–mainly Ceratoneis arcus Kz. and varieties, Fragilaria spp., and Synedra spp.–were predominant in the community floating among the filaments with maximum standing crop (64.48 × 106 cells/g dry weight of Mougeotia) occurring in July. The small diameter of the Mougeotia filaments was probably the main factor limiting the size of both the attached and free‐floating communities.
UPTAKE AND RELEASE OF METHYLMERCURY‐203 BYCLADOPHORA GLOMERATA1
Authors: Burkett Robert D.
Published: August 2007

Cladophora glomeratawas exposed to CH3203HgCl at concentrations of 10, 50, and 100 μg/liter of water. Formalin‐killed alga was exposed to a concentration of 50 μg CH3203HgCl/liter. Uptake was monitored at 2 and 12 hr, and days 1, 2, 4, 8, and 16. At the end of this period, theCladophorawas placed in uncontaminated water, and release of methylmercury was monitored at 1, 2, 4, 8, and 16 days. Sorption occurred at all concentrations, and the live algal material accumulated more methylmercury than the dead alga, at equal exposure concentrations. Accumulation of methylmercury by the liveCladophorapeaked on or near the second day for all exposure concentrations, suggesting that the uptake rate was independent of methylmercury concentration in the water. Uptake was greatest at the 50 μg/liter exposure. Desorption was nominal during the 16‐day release period. The mechanisms of methylmercury uptake byCladophoraare discussed.
A SEAWATER MEDIUM FOR DINOFLAGELLATES AND THE NUTRITION OF CACHONINA NIEI1
Authors: R. Loeblich Alfred
Published: August 2007

Two media have been devised: an enriched seawater medium for culture of dinoflagellates and a defined medium for rapid growth of the dinoflagellate Cachonina niei. A wide range in salinity (10.23–42.38 g/liter NaCl) is tolerated by C. niei. Below 0.6 g/liter MgSO4, 0.19 g/liter KCl, and 0.22 g/liter CaCl2, the generation time greatly increases. Increase in MgSO4 to 7.22 g/liter, KCl to 1.12 g/liter or CaCl2 to 2.22 g/liter has little effect on generation time. The temperature optimum is 19–23 C. Saturating light intensity for growth is 1000 ft‐c and for photosynthesis (determined manometrically) is slightly less than 2000 ft‐c. Cachonina niei requires B12 and thiamin. Neither silicate nor its competitive inhibitor germanate affects generation time or cell yield indicating silicon is not required. Of a variety of buffers tested, Tris is the best. Optimal growth occurs at pHs of 7.5–8.3. Glycerol is inhibitory and does not support dark growth.
THE ULTRASTRUCTURE OF MULTILAYERED STRUCTURES ASSOCIATED WITH FLAGELLAR BASES IN MOTILE CELLS OFTRENTEPOHLIA AUREA1
Authors: Graham Linda E. , McBride Gordon E.
Published: August 2007

An ultrastructural study of motile cell development in the green algaTrentepohlia aureahas revealed the presence of multilayered structures (MLS) associated With flagellar bases. These MLS are ultrastructurally similar to MLS described in pteridophyte and bryophyte sperm and in the zoospore of the green algaeColeochaeteandKlebsormidium.However, 2 MLS are found in each biflagellate motile cell ofT. aurea, while other previously described MLS occur singly in biflagellate motile cells. In addition, the MLS ofT. aureaconsist of fewer microtubules and are structurally simpler than most other MLS described. The MLS ofTrentepohliamay represent a stage in the evolutionary development of the MLS of land plants. The presence or absence of the MLS in motile cells of green algae may be a useful character in phylogenetic studies.
CHEMOTAXONOMY IN MARINE ALGAE: CHEMICAL SEPARATION OF SOME LAURENCIA SPECIES (RHODOPHYTA) FROM THE GULF OF CALIFORNIA1
Authors: Fenical William , Norris James N.
Published: August 2007

Species separation in the genus Laurencia (Rhodomelaceae, Rhodophyta) is complicated by the high degree of morphological variation within the species. Chemical investigations on a worldwide basis of over 15 species indicate that 1 or more of the halogenated natural products synthesized by Laurencia are unique to each species. Our chemical investigations of Laurencia pacifica, as presently understood from the Gulf of California, indicate that more than 1 species had been included under this name. Thin layer chromatographic (TLC) comparisons of the halogenated components of 3 recognizable forms of “L. pacifica” were completed. The results revealed 3 distinct forms, with halogenated products unique to each form. In each form the observed chemical characters had been previously isolated and identified and could now be positively assigned to their algal source. Comparisons were also conducted with L. pacifica Kylin (1941) from the type locality of the species, La Jolla, California, and revealed that it contained another halogenated product different from those isolated from the Gulf species.

We conclude that 3 species of Laurencia have been elucidated in the Gulf of California and these are separate from L. pacifica Kylin. Each species can be distinguished by its characteristic array of halogenated compounds. Comparative thin layer chromatography of the lipid components of morphologically similar Laurencia species should prove to be a useful new taxonomic aid.
THE DISTRIBUTION OF PHOTOSYNTHATE IN ASCOPHYLLUM NODOSUM AS IT RELATES TO EPIPHYTIC POLYSIPHONIA LANOSA12
Authors: Harlin Marilyn M. , Craigie J. S.
Published: August 2007

The brown alga Ascophyllum nodosum is not a major source of organic carbon for its epiphytic red alga Polysiphonia lanosa. Plants pulse‐labeled for 24–25 hr with NaH14CO3 were examined for exudation and translocation. The maximum amount of radioactive carbon compounds lost from A. nodosum during this experimental period was less than 0.3% of the total 14C fixed by the alga, and of this amount, only 5% could, have moved through the frond. The remaining fraction of the 14C lost from the thallus was released into the water.

The total exudate from A. nodosum was collected for 1 week in a series of flasks of filtered seawater changed at 12‐hr intervals corresponding with the beginning of the light and dark periods, respectively. During 7 days at 15 C only 1.5% of the total 14C originally fixed had been released as radioactive organic carbon, whereas at 5 C, 0.6% of the total 14C fixed was found in the medium. No significant difference in the rate of exudation of organic 14C was observed in light or darkness. After fractionation of the exudate it was found that only 10% of the radioactivity in these exudates was composed of organic acids or amino acids.

P. lanosa, on the other hand, is perfectly capable of fixing its own carbon. The photosynthetic rates measured by H14CO3 uptake confirm the observations of Bidwell: 3.96 mg CO2/g/hr (0.09 m mole/g/hr).
FINE STRUCTURE OF CELL DIVISION INPYRAMIMONAS PARKEAENORRIS AND PEARSON (CHLOROPHYTA, PRASINOPHYCEAE)1
Authors: Pearson Barbara R. , Norris Richard E.
Published: August 2007

Cell division inPyramimonas parkeaeis described and compared with some other green algae. The first indication of mitosis is division of the chloroplast, accompanied by growth of a prominent microbody, followed by replication of the 4 basal bodies. Also closely timed with this is the replication of the Golgi and other components of the basal body complex. Two basal body complexes separate, each taking a position at either pole of the nucleus which has migrated to a characteristic position just beneath the plasmalemma of a broadened and flattened flagellar pit. Cytokinesis is accomplished by the fusion of ducts and vesicles with the simultaneous release of scales to the newly formed exterior. Cells swim throughout division.
THE STATOSPORE OF DINOBRYON DIVERGENS IMHOF: FORMATION AND GERMINATION IN A SUBARCTIC LAKE1
Authors: Sheath Robert G. , Hellebust Johan A. , Sawa Takashi
Published: August 2007

The population dynamics and the sequences of statospore development and germination of Dinobryon divergens from a shallow subarctic lake were examined. D. divergens showed a sharp increase in the vegetative cell population between June 19 and July 3, 1973, followed by a rapid formation of statospores from June 26 to July 3. Shortly after spore production, this species decreased sharply to an insignificant level in the phytoplankton. Statospore formation to as initialed by migration of the monad cell to the lorica mouth and proceeded by rounding up of the cytoplasm. There was then an unequal cleavage, silica wall formation around the larger portion of the cytoplasm including the nucleus and disintegration of the extracystic cytoplasm after development of the plug. The statospore was uninucleate throughout its development, and it was concluded that spore formation occurred asexually. Germination of statospores was observed in periphyton samples at depths of 20 and 80 cm on July 20–21, 1973 and in the sediments earlier the following year. During germination a cellulose chamber was produced from the pore of the statospore, followed, by cleavage of the cytoplasm within the spore and migration of approximately 4 daughter protoplasts into the cellulose chamber from which they eventually escaped. The present study proposes that chrysophycean statospores arising asexually and endogenously should be recognized as separate entities from those formed isogamously and autogamously but not necessarily endogenously. The latter statospores resulting from the sexual process have been given the term zygospore.
HYMENOMONAS CORONATA SP. NOV., A NEW COCCOLITHOPHORID FROM THE TEXAS COAST1,2
Authors: Mills Jimmy T.
Published: August 2007

A new species of Hymenomonas (H. coronata) has been isolated from the Texas coast, grown in axenic culture, and examined by both light and electron microscopy. Certain cultural and ultrastructural observations are presented. This alga has several haptophycean characteristics, although a definite haptonema has not been observed. Similarities to other members of the genus are evident, such us type and shape of coccoliths and pyrenoid‐chloroplast morphology.
PHOSPHORUS, NITROGEN AND THE GROWTH OF ALGAE IN LAKE KINNERET1
Authors: Serruya Colette , Berman Thomas
Published: August 2007

The intracellular concentrations of carbon, nitrogen, phosphorus and chlorophyll a of phytoplankton and zooplankton in Lake Kinneret were determined from 1969 to 1973. The ratios C:P, C:N, chlorophyll a:P, chlorophyll a:N of the algae showed fluctuations which could be related to the nutrient conditions that influence the annual pattern of phytoplankton development, especially in respect to the dinoflagellate bloom of Peridinium cinctum (OFM) Ehr. f. westii (Lemm.) Lef. Relatively high intracellurar P values at the start of the bloom indicated adequate availability of this nutrient and luxury consumption over a short period of time. Later, Peridinium continued to grow despite unusually high C:P ratios (> 300:1). In most years, phosphorus may have eventually limited growth, however, in 1970, the bloom censed despite comparatively high intracellular P concentrations. These observations, together with supplementary evidence from nutrient addition experiments and determinations of specific alkaline phosphatase levels, indicated that, for most of the growth phase of the bloom, Peridinium cells were not directly limited by P. The decline of the bloom usually, but not always (e.g., in 1970), was marked by very high C:P ratios. Thus, a shortage of P may often be a contributory factor to the cessation of the Peridinium bloom and may be limiting phytoplankton growth in the fall. Over the years 1969–73, possibly due to an overall drop in salinity, there appears to be a trend to lower levels of biologically bound phosphorus in Lake Kinneret, without a concomitant decrease in carbon biomass.
A STUDY OF THE SPERMATOZOIDS OF DICHOTOMOSIPHON TUBEROSUS (CHLOROPHYCEAE)1
Authors: Moestrup Øjvind , Hoffman Larry R.
Published: August 2007

Spermatozoids of the siphonous green alga Dichotomosiphon tuberosus (A. Br.) Ernst are specialized gametes which differ in many respects from other green algal motile cells, but whose microanatomy nevertheless indicates its chlorophycean affinities. Each cell is anteriorly biflagellate and contains an irregularly shaped nucleus attached to the flagellar bases by a complex support apparatus. There is a single reduced chloroplast in each spermatozoid and numerous (50–100) minute spherical mitochondria, only 0.3 μm diam. These move vigorously in the living cell and when viewed with the light microscope they bear a striking resemblance to bacteria. Rather unexpectedly, no contractile vacuoles could be detected, even though the gametes are naked freshwater cells. Daring spermatogenesis the nucleoli of the vegetative cells disperse and are replaced by a large dense body presumably formed from either nucleolar material or condensed chromatin. The flagellar apparatus includes a cruciate flagellar root system, a feature now known to be characteristic of most green algae, exceptions being those putative ancestors of the higher plants and bryophytes. Discharge of spermatozoids from the antheridia is extremely rapid and the whole process may be finished in 30 sec. The antheridium lacks a pore apparatus, but at maturity bursts open explosively at the apex. Phyletic affinities are discussed and it is concluded that the ultrastructure of the motile cells does not, at this time, support the separation of the siphonous green algae from other green algae into a separate class.
COLACIUM LIBELLAE SP. NOV. (EUGLENOPHYCEAE), A PHOTOSYNTHETIC INHABITANT OF THE LARVAL DAMSELFLY RECTUM1
Authors: Rosowski James R. , Willey Ruth L.
Published: August 2007

Colacium libellae sp. nov., in the non‐flagellated palmella stage and lacking stalks, lines the cuticle of the rectum of damselfly larvae, forming a conspicuous green plug. In culture this species forms highly‐branched colonies of stalked cells. The cells tire often elongated to twice the size of most motile cells (40–50 × 6–10 μm), with parallel sides and rounded apices. These features are distinctive when comparisons are made among clones of related species in soil‐water‐pea medium. C. libellae established itself in the rectum of previously Colacium‐free larvae of the damsel fly Anomalagrion hastatum whereas a clone of C. vesiculosum and C. mucronatum did not.
MOLYBDENUM DEPENDENCE, NITRATE UPTAKE AND PHOTOSYNTHESIS OF FRESHWATER PLANKTON ALGAE1,2
Authors: Wallen D. G. , Cartier L. D.
Published: August 2007

The effects of molybdenum on photosynthesis and nitrate uptake by two species of freshwater algae, Navicula pelliculosa (Bréd.) Hilse and Chlamydomonas reinhardtii Dang. Were examined. Photosynthetic rates in cells of N. Pelliculosa deprived of Mo for 48 h were significantly lower than in nondeprived cells; the rates were 2.6 and 4.5 μg C/106 cells/h, respectively. There was no significant reduction in photosynthetic rates of C. reinhardtii under the 2 treatments, the rates were both ca. 6.0 μg C/106 cells/h. These observed rates in the 2 species were not altered by added Mo concentrations as high as 1.0 ppm. The chlorophyll a values in 48 h Mo‐deprived cells were 1.15 μg/106 cells compared to 1.57 μg/106 cells provided with this metal. Molybdenum deficiency did not affect the chlorophyll a concentration in Chlamydomonas; the chlorophyll levels were 2.44μg/106 cells.

Nitrate uptake by Mo‐deprived cells of N. Pelliculosa was significantly lower than in cells cultured in Mo; the rates were 0.087 and 0.238 μM NOa−/106 cells/h, respectively. Uptake rates by C. reinhardtii were similar with or deprived of Mo. The Km values for No3− uptake were 14.9 and 148.0 μM for N. Pelliculosa and C. reinhardtii, respectively.
LIGHT/DARK‐PHASED CELL DIVISION IN EUGLENA GRACILIS (Z) (EUGLENOPHYCEAE) IN PO4‐LIMITED CONTINUOUS CULTURE1
Authors: Chisholm S. W. , Stross Raymond G. , Nobbs Paul A.
Published: August 2007

Eugene gracilis Klebs (Z) was grown in a cyclostat (continuous culture on a light/dark cycle) at growth limiting levels of phosphate. Cell division was restricted to the dark period regardless of the proportion of the cells dividing during each 24 h period. Growth rate, as reflected by the amplitude of the cell density oscillation, was correlated with dilution rate. The width of the division gate was analyzed using a phasing index and found to be narrowest at dilution rates where the mean generation time of the cell population was an even multiple of 24 h. The effect was attributed to enhanced phasing of the cell division process by the biological clock of Euglena.

Residual phosphate levels in the cyclostat were less than 0.3 μM PO4 at all submaximal growth rates. Cellular phosphorus concentration increased with dilution rate as described by a hyperbola saturating at Dmax= 0.74 day−1 with 8 × 10−8μM P/cell as the minimum intracellular phosphorus concentration for growth.

The results are discussed, in terms of the inherent similarities and differences between a cyclostat and a steady state chemostat, and the advantages of the cyclostat for studies in phytoplankton ecology.
DIATOM COMMUNITIES FROM A DELAWARE SALT MARSH 1,2
Authors: Sullivan Michael J.
Published: August 2007

Edaphic diatoms were collected from 5 representative habitats of Canary Creek salt marsh, Lewes, Delaware, from 24 July 1969 to 21 July 1970. Of the 104 taxa encountered, 32 had a general distribution on the marsh and 41 were endemic to one of the 5 habitats sampled. Three of the habitats supported stands of grasses: tall Spartina alterniflora Loisel., dwarf S. alterniflora, and Distichlis spicata (L.) Greene; and these habitats possessed the highest species diversity (H') and the greatest number of diatom species. The remaining 2 habitats, a bare bank and a panne, were devoid of macroscopic vegetation. The diatoms of these last 2 habitats were exposed to hypersaline conditions during warmer periods of the year and this was considered a contributing factor to the lower values observed for the aforementioned parameters of community structure. A comprehensive examination of the community structure characterizing the 5 habitats, employing statistical analyses and the distribution of species, showed each habitat to support its own unique and easily recognizable edaphic diatom community. A multiple regression analysis indicated that the differences between the 5 communities were closely related to differences in temperature and elevation between the habitats, and also a result of significant interactions between edaphic diatoms and filamentous algae.
MORPHOLOGY OF PLACENTOPHORA (SOLIERIACEAE, GIGARTINALES: RHODOPHYTA), A NEW GENUS BASED ON SARCODIOTHECA COLENSOI FROM NEW ZEALAND1
Authors: Kraft Gerald T.
Published: August 2007

The only member of the red algal family Solieriaceae known from New Zealand is the endemic Sarcodiotheca colensoi (Hook. & Harv.) Kylin. This study shows that it differs in several respects from the type S. furcata (Setch. & Gard.) Kylin; thus a new genus Placentophora is created for the New Zealand alga. Although P. colensoi nov. comb. is retained in the Solieriaceae on the basis of vegetative, spermatangial, tetrasporangial, carpogonial‐branch and early gonimoblast features, it differs from typical members of that family in its pattern of later carposporophyte development. After a single gonimoblast initial is cut off from the auxiliary cell towards the center of the thallus, further gonimoblasts develop from the initial as ramifying, radiating filaments. These filaments enter an extensive “nutritive‐cell” region surrounding the auxiliary cell, form, numerous connections to the “nutritive” cells, and incorporate most of them into a central placenta of interconnected, and variously‐fused vegetative and gonimoblast cells. Carpo‐sporangia then form in short chains around the periphery of the placenta. The cystocarp lacks both a central fusion cell and a sterile‐celled investment, or “Faserhülle.” The distinctive carposporophyte of Placentophora is compared to patterns of gonimoblast development, known in other members of the Solieriaceae.
CULTURE AND HYBRIDIZATION STUDIES ON PETROCELIS (RHODOPHYTA) FROM ALASKA AND CALIFORNIA1,2
Authors: Polanshek Alan R. , West John A.
Published: August 2007

Cultured tetraspores of Petrocelis middendorffii (Ruprecht) Kjellman from Amchitka Island, Alaska, gave rise to foliose, dioecious gametophytes similar to cultured gametophytes of P. franciscana Setchell & Gardner. A 1:1 ratio male:female gametophytes was obtained. Fertilized female plants produced cystocarps and carpospores that gave rise to crustose plants anatomically similar to field‐collected Petro‐celis sporophytes. Cultured male gametophytes of P. middendorffii were interfertile with cultured female blades of field‐collected Gigartina pacifica Kjellman. Cultured P. middendorffii gametophytes from Amchitka were interfertile with cultured gametophytes of P. franciscana from 2 localities in California. Hybrid carpospores gave rise to crustose sporophytes that have not reproduced. Anatomical comparisons of P. middendorffii from Amchitka with P. franciscana from California showed no important differences in the characters originally used to separate these species. The interfertility of cultured Petrocelis gametophytes from california and Amchitka as well as the similarities of the history and anatomy suggests that a single species is involved. P. franciscana is reduced to a synonym of P. middendorfii.
ULTRASONIC REMOVAL OF EPILITHIC ALGAE IN A BAR‐CLAMP SAMPLER1,2
Authors: Gale William F.
Published: August 2007

A bar clamp with a collecting cup attached was used to collect epilithic algae samples on stones 4–50 cm diam.; stones were sampled by wading in shallow water and by SCUBA diving in deep water. The collecting cup delimits the sampling area (a 22 mm diam. circle) for cleaning and protects it from cell loss and desiccation. On some stones, ultrasonic vibration removed large numbers of cells (up to 62% of the total) missed by scraping and brushing.
Sex-linked differences in pulse oxymetry
Authors: Ricart de Mesones Antoni , Pages Costas Teresa , Viscor Carrasco Gines , Leal Tort Conxita , Ventura Farre Josep Lluis
Published: August 2007

Knowledge of gender-differences is of increasing interest in recent years. It is well known that women and men show differences in their respiratory system. It is well known that they have different red blood cells count and haemoglobin plasma concentration. Later, other differences have been found in the ventilatory response to hypoxia and exercise and the evolution of some respiratory illnesses. The present study brings forward that during rest at sea level, the haemoglobin oxygen saturation, measured by pulse oxymetry, is slightly higher in women than in men (98.6±1.1% versus 97.9±0.9%; P=0.001). Other studies had found gender differences in the transcutaneous or tissue PaO2that is consistent with our findings. The difference in the oxygen saturation is not related to differences in ventilation. The difference is modest and does not seem to produce great differences in the oxygen content of arterial blood, but added to the differences in the affinity of haemoglobin for oxygen or the different metabolic rate, may play a role in the course of elite competition sports, high altitude ascents or the evaluation of critically ill patients. Consequently, even if further studies are needed to know the degree, extent and clinical importance, women and men have differences in the saturation of the haemoglobin measured by pulse oxymetry.
Vessel wall stiffness in type 1 diabetes and the central hemodynamic effects of acute hypoglycemia
Authors: Sommerfield Andrew J. , Wilkinson Ian B. , Webb David J. , Frier Brian M.
Published: August 2007

Objective: To examine the effects of intravenous insulin and acute hypoglycemia on arterial wall stiffness and central hemodynamic responses in adults with and without type 1 diabetes. Research Design and Methods: In 30 young male volunteers [10 nondiabetic ( Group 1); 10 with type 1 diabetes, <5 yr duration ( Group 2); 10 with type 1 diabetes, >15 yr duration ( Group 3)], intravenous insulin was administered to provoke an acute autonomic reaction (R) to hypoglycemia. Heart rate, peripheral blood pressure, and pulse wave analysis (radial artery) were monitored. Augmentation index (AIx), a measure of arterial wall stiffness and wave reflection, and central arterial pressure were recorded. Results: At baseline, no significant differences were observed between Groups 1 and 2 in either AIx or in central arterial pressure, but in Group 3, both measures were significantly higher. All three groups exhibited similar responses to intravenous infusion of insulin and to hypoglycemia: AIx fell progressively from baseline to R, peripheral systolic blood pressure increased, and central systolic pressure decreased. Conclusion: Compared with age- and sex-matched nondiabetic controls, people who had type 1 diabetes for a long duration had increased stiffness of vessel walls. The opposing responses in peripheral and central systolic pressures during hypoglycemia may be related to the reduction in AIx, which causes diminished amplification of the systolic pressure wave. Changes in AIx are probably mediated by a direct action of insulin on arterial endothelium, or changes in heart rate. These functional changes may contribute to the increased cardiovascular morbidity that is associated with type 1 diabetes of long duration.
Obesity-associated mouse adipose stem cell secretion of monocyte chemotactic protein-1
Authors: Zhou Hui Ren , Kim Eun-Kyoung , Kim Hyojung , Claycombe Kate J.
Published: August 2007

Studies showed that monocyte chemotactic protein-1 (MCP-1) concentrations are increased in obesity. In our current study, we demonstrate that plasma MCP-1 level in leptin-deficient ob/ob mice is significantly higher than in lean mice. Furthermore, we determined that basal adipose tissue MCP-1 mRNA levels are significantly higher in ob/ob mice compared with lean mice. To determine the mechanisms underlying obesity-associated increases in plasma and adipose tissue MCP-1 levels, we determined adipose tissue cell type sources of MCP-1 production. Our data show that adipose tissue stem cells (CD34+), macrophages (F4/80+), and stromal vascular fraction (SVF) cells express significantly higher levels of MCP-1 compared with adipocytes under both basal and lipopolysaccharide (LPS)-stimulated conditions. Furthermore, basal and LPS-induced MCP-1 secretion levels were the same for both adipose F4/80+and CD34+cells, whereas adipose CD34+cells have twofold higher cell numbers (30% of total SVF cells) compared with F4/80+macrophages (15%). Our data also show that CD34+cells from visceral adipose tissue depots secrete significantly higher levels of MCP-1 ex vivo when compared with CD34+cells from subcutaneous adipose tissue depots. Taken together, our data suggest that adipose CD34+stem cells may play an important role in obesity-associated increases in plasma MCP-1 levels.
Norepinephrine and rosiglitazone synergistically induceElovl3expression in brown adipocytes
Authors: Jörgensen Johanna A. , Zadravec Damir , Jacobsson Anders
Published: August 2007

The Elovl3 gene, which putatively encodes for a protein involved in the elongation of saturated and monounsaturated fatty acids in the C20–C24 range, is expressed in murine liver, skin, and brown adipose tissue (BAT). In BAT, Elovl3 is dramatically upregulated during tissue activation in response to cold exposure, and functional data imply that ELOVL3 is a critical enzyme for lipid accumulation in brown adipocytes during the early phase of tissue recruitment. The activation of BAT is controlled by sympathetic nerve activity and norepinephrine release. By using primary cultures of brown adipocytes, we show here that the induced Elovl3 gene expression is synergistically regulated by norepinephrine and the peroxisome proliferator-activated receptor (PPAR) γ ligand rosiglitazone. In addition, the potency of rosiglitazone to induce Elovl3 expression was several orders of magnitude higher than for the PPARα and PPARδ ligands WY-14643 and L-165041, respectively. The maximal increase in mRNA level by norepinephrine and rosiglitazone is achieved by induced transcription as well as increased mRNA stability, and the whole process requires novel protein synthesis. We conclude that norepinehrine and PPARγ, despite having different roles in brown adipocyte activation and differentiation, cooperate in expanding the intracellular lipid pool by synergistically stimulating Elovl3 expression.
NMDA Receptor Trafficking at Recurrent Synapses Stabilizes the State of the CA3 Network
Authors: Hellier Jennifer L. , Grosshans David R. , Coultrap Steven J. , Jones Jethro P. , Dobelis Peter , Browning Michael D. , Staley Kevin J.
Published: August 2007

Metaplasticity describes the stabilization of synaptic strength such that strong synapses are likely to remain strong while weak synapses are likely to remain weak. A potential mechanism for metaplasticity is a correlated change in both N-methyl-d-aspartate (NMDA) receptor-mediated postsynaptic conductance and synaptic strength. Synchronous activation of CA3–CA3 synapses during spontaneous bursts of population activity caused long-term potentiation (LTP) of recurrent CA3–CA3 glutamatergic synapses under control conditions and depotentiation when NMDA receptors were partially blocked by competitive antagonists. LTP was associated with a significant increase in membrane-bound NMDA receptors, whereas depotentiation was associated with a significant decrease in membrane-bound NMDA receptors. During burst activity, further depotentiation could be induced by sequential reductions in antagonist concentration, consistent with a depotentiation-associated reduction in membrane-bound NMDA receptors. The decrease in number of membrane-bound NMDA receptors associated with depotentiation reduced the probability of subsequent potentiation of weakened synapses in the face of ongoing synchronous network activity. This molecular mechanism stabilizes synaptic strength, which in turn stabilizes the state of the CA3 neuronal network, reflected in the frequency of spontaneous population bursts.