bluuebunny/crossref_metadata_2025_split huggingface dataset:
ULTRASTRUCTURE OF THE CONCHOCELIS STAGE OF THE MARINE RED ALGA PORPHYRA LEUCOSTICTA1
Authors: Lee Robert Edward , Fultz Sara A. 
Published: August 2007

SUMMARYThe ultrastructure of the Conchocelis or filamentous stage of Porphyra leucosticta was investigated. Each cell contains 1 or 2 parietal, stellate chloroplasts with a single pyrenoid in each chloroplast. The centrally located nucleus is irregularly shaped and contains 1–2 nucleoli. The cytoplasm has typical floridean starch grains and nonmernbrane‐bound lipid bodies. The cell wall is divided into an outer and an inner wall. Many lomasomes are associated with the cell membrane. Pit connections are found between cells, and their taxonomic significance is discussed.
OBSERVATIONS ON THE FINE STRUCTURE OF THE CRYPTOPHYCEAE. I. THE GENUS CRYPTOMONAS1,2
Authors: Lucas I. A. N. 
Published: August 2007

SUMMARYThe fine structure of 3 members of the genus Cryptomonas, C. rostrella, C. reticulata, and C. calceiformis, has been examined. These species exhibit the features typical of the class Cryptophyceae. The presence of subpellicular trichocysts causes a regular folding of the periplast, and larger trichocysts are present within the gullet. The plastid contains thylacoids arranged in pairs and a prominent pyrenoid; both structures are enclosed in 4 membranes, the outermost of which is a rough endoplasmic reticulum. The nucleus, Golgi apparatus and the Corps de Maupas occupy characteristic positions within the cell, and are the most characteristic features. All these structures indicate that this algal class occupies a unique phylogenetic position.
GROWTH PATTERNS AND MOTILITY OF SPIROGYRA SP. AND CLOSTERIUM ACEROSUM1,2
Authors: Yeh Pao‐Zun , Gibor A. 
Published: August 2007

SUMMARY Spirogyra and Closterium exhibit active motility. This motility is associated with the secretion of pectic mucilage from the cells. The gliding of these cells is not directed toward light but photosynthesis is the energy source for it. The secretion of mucilage causes older Closterium cultures to become thick gelatinous clusters. Spirogyra filaments when undisturbed grow to form thick multistranded rings. This growth pattern might result from the tendency of the filaments to rotate on their long axis.
ON THE MECHANISM OF THE INHIBITION OF GROWTH BY XYLULOSE IN CHLOROCOCCUM ECHINOZYGOTUM1,2
Authors: Wu M. , Alston R. E. , Mabry T. J. 
Published: August 2007

SUMMARYWe previously established that xylulose inhibits the growth of the green alga Chlorococcum echinozygotum. Utilizing experiments involving exposure of the alga to NaHC14O3, it was possible to show by counting the C14 activity of methanolic extracts of the algal cells that xylulose inhibited CO2 uptake. Subsequently it was shown that xylulose does not inhibit or otherwise influence the Hill reaction in this alga.Several enzymes related to xylulose metabolism were investigated. It was found that xylulokinase was active in C. echinozygotum while phosphoketolase activity was absent. Transketolase was present but its activity was not notably affected by xylulose. Crude carboxydismutase preparations were found to be inhibited by xylulose and xylulose 5‐phosphate. However, as carboxydismutase was purified further, this inhibition was relatively less. When xylulose 1,5‐diphosphate was prepared synthetically, this compound was found to be the most effective inhibitor of purified algal carboxydismutase. We conclude that d‐xylulose enters the cells of C. echinozygotum where it is converted to d‐xylulose 1,5‐diphosphate which acts as a competitive inhibitor of carboxydismutase.
COMPARATIVE STUDIES IN THE GENUS PORPHYRIDIUM NAEG.1,2
Authors: Sommerfeld Milton R. , Nichols H. Wayne 
Published: August 2007

SUMMARYSeven isolates of Porphyridium from 2 species were compared. P. cruentum Naeg. isolates were similar in size and pigmentation; differences were observed among the P. aerugineum Geit. isolates. Differences were detected among isolates in reproduction, rate of movement, growth rate, and sensitivity to CuSO4 and crystal violet. No isolate grew heterotropically; however, growth differences were apparent on various carbon sources.
REQUIREMENTS FOR THE MAINTENANCE AND GROWTH OF APHANIZOMENON FLOS‐AQUAE IN CULTURE1,2
Authors: O'Flaherty Larrance M. , Phinney Harry K. 
Published: August 2007

SUMMARY Aphanizomenon flos‐aquae has been introduced into unialgal culture in a completely defined medium and maintained for more than 3 years in the colonial flake form found in nature. The color and size of the flake and general appearance of the cells are substantially improved over those found in the original material at the time of collection from Upper Klamath Lake, Klamath County, Oregon. The alga readily forms both akinetes and heterocysts in culture Bacteria‐free cultures have not been obtained.A precipitate‐free medium designated ASM No. 8a has been developed from the ASM of McLachlan and Gorham. Their medium was altered by modifying the concentration of certain elements and by the addition of sodium bicarbonate, a 1/25 dilution of Arnon's trace element solutions B7 and C13, hydrogen ferric ethylenediamine di‐o‐hydroxyphenylacetate (EDDHA), and disodium ethylene dinitrilotetra‐acetate (Na2EDTA).
DISTRIBUTION AND TAXONOMIC REAPPRAISAL OF CTENOCLADUS (CHLOROPHYCEAE: CHAETOPHORALES)1,2
Authors: Blinn Dean W. , Stein Janet R. 
Published: August 2007

SUMMARYThe distribution of the rare filamentous green alga Ctenocladus Borzi was examined on a world‐wide basis. All the collection sites are restricted to specific inland habitats. Most of these locations are in arid regions of North America with a few scattered sites in Peru, Sicily, and Siberia. This alga has been referred to 2 genera, either Ctenocladus or Lochmiopsis Woronochin & Popova, for the past 45 years. Based on field observations, laboratory cultures, and herbarium material, Lochmiopsis is considered synonymous with Ctenocladus.The response of vegetative cell dimensions to seasonal changes (i.e., osmotic potential and temperature) in 3 saline habitats in British Columbia was also investigated. Results from the study, along with laboratory dilutions of natural saline waters, showed that cell dimensions arc not valid criteria for separating species of Ctenocladus as proposed by some authors. Consequently Ctenocladus is considered a monotypic genus with physiological variants responding to seasonal environmental conditions.
SUCCESSION AND CURRENT DEMAND RELATIONSHIPS OF DIATOMS ON ARTIFICIAL SUBSTRATES IN PRATER'S CREEK, SOUTH CAROLINA1,2
Authors: Reisen William K. , Spencer Deirdre J. 
Published: August 2007

SUMMARYA study concerning the colonization of glass slides by diatoms was conducted in Prater's Creek, Pickens County. S. C., to observe qualitatively and quantitatively the responses of the periphytic community to current velocities for varied lengths of time. Over short time periods (1, 2 and 4 weeks) diatoms seemed to adhere best at slow current velocities. Over longer periods (6 weeks) growth, of the initial colonizers seemed to be the density governing factor; consequently, the highest diatom densities developed at the higher current, velocities. The interaction of time and current resulted in a reversal of the diatom deposition phenomenon.
MORPHOLOGY AND TAXONOMY OF THE EURYHALINE CHRYSOPHYTE, SPHAERIDIOTHRIX COMPRESSA1
Authors: Andrews Hollings T. 
Published: August 2007

SUMMARY Sphaeridiothrix compressa was found in a. saline pond in central Kansas in 1966. Studies in culture have shown that it reproduces readily by zoosporogenesis when grown in media of 12–21 ppt (%0) total salt. Its taxonomic position in the Chrysophyceae and synonymy with S. globulosa, S. brunea, and Chrysodictyon indicum are discussed. This is the first report of Sphaeridiothrix in the Western Hemisphere, and the first account of zoosporogenesis in the genus.
CHANGES IN ABSORBANCE SPECTRUM OF THE DIATOM PHAEODACTYLUM TRICORNUTUM UPON MODIFICATION OF PROTEIN STRUCTURE1,2
Authors: Margulies Maurice M. 
Published: August 2007

SUMMARYChanges in the absorbance spectrum, of the diatom Phaeodactylum tricornutum which are brought about by heat, urea, stilt, and formaldehyde have been studied. The changes brought about by all agents are similar. Each converts cell suspensions from orange‐brown to yellow‐green. This color change results from an increase in absorbance in the blue and a decrease in absorbance in the green. All agents, except salt, also bring about an increase in absorbance in the red at wavelengths below that of the red peak of chlorophyll, and a decrease in absorbance at longer wavelengths. On heating cells, the absorbance change in the green occurs more rapidly than the changes in the blue and red. The converse is true when cells are treated with 4 M NaCl. Heat or formaldehyde treatments chemically modify chlorophyll pigments which are present in untreated cells. The change in absorbance in the green is probably due to changes in the molecular environment of fucoxanthin which, results from protein modification. The changes in the blue and red are at least partly due to chemical changes in chlorophylls, but may also be due, in part, to protein modification.
STUDIES ON THE PHOTOBIOLOGY OF BANGIA FUSCOPURPUREA1
Authors: Richardson Norman 
Published: August 2007

SUMMARYIn the Rhodophyta there are few reports of light‐mediated responses. In Bangia fuscopurpurea the formation of the fertile cell rows by the Conchocelis phase meets criteria established for the definition of photoperiodism in higher plants. Throughout the life history of the alga maintained in culture, cell fate and cell function fire under photoperiodic regulation. Maintenance and conversion photoperiods are established. Sequential induction studies suggest the absence of metabolic effects operative in the induction, response of fertile cell row formation. Preliminary studies of non‐24‐hr photoperiods suggest the absence of short‐term endogenous rhythms involved in spore formation. A phytochrome response involved in the formation of the fertile cell rows is demonstrated.
CULTIVATION OF A FILAMENTOUS ALGA IN QUANTITY ON AGAR PLATES1,2
Authors: Rosowski James R. , Hoshaw Robert W. 
Published: August 2007

SUMMARYA method for the cultivation of Zygnema in quantity on agar plates is described. Axenic filaments were chopped with razor blades, and 4 ml of the suspension of short filaments in nutrient medium were transferred with a syringe to 1% agarized nutrient medium plates. Filamentous growth uniformly covered agar plates in 10 days or less.
KINETICS OF GLUCOSE TRANSPORT AND GROWTH OF CYCLOTELLA CRYPTICA REIMANN, LEWIN AND GUILLARD1,2
Authors: Hellebust Johan A. 
Published: August 2007

SUMMARYGrowth rate as well as rate of glucose uptake of C. cryptica depends on glucose concentration in the medium according to saturation kinetics. The Kg for growth is 1.9 × 10−5 M, and the Kt, for glucose transport is 5.8 × 10−5 M. The maximum growth rate in the dark on glucose is considerably slower than the light‐saturated growth rate at the same temperature, and does not appear to be determined by the capacity of the cell for glucose uptake.The glucose transport process is highly specific, and depends on energy metabolism. The Q10 for the process is 2.2 (15–2.5 C). Glucose taken up by the cells is almost, quantitatively phosphorylated within 10 min, either through the transport process itself or by a high affinity kinase system in the cells.
SPHEROPLAST FORMATION AND ASSOCIATED ULTRASTRUCTURAL CHANGES IN A SYNCHRONOUS CULTURE OFANACYSTIS NIDULANSTREATED WITH LYSOZYME1,2
Authors: Lindsey Jerri K. , Vance B. Dwain , Keeter Joe S. , Scholes Vernon E. 
Published: August 2007

SUMMARYCells ofAnacystis nidnlanswere grown in synchronous culture using a light‐dark alternation to obtain synchronization. Two synchronous cycles were obtained with, decay of synchrony beginning with the third cycle. Cells of various ages in the growth cycle were treated with lysozyme to form spheroplasts. The percentage of spheroplast formation varied with age of the cells. After extended periods of lysozyme treatment, up to 90% of the cells of all ages showed spheroplast formation. Some cells were resistant to the action of lysozyme regardless of age or length of treatment. An ultrastructure study of the spheroplast was made. The electron‐dense inner layer of the cell wall was removed by the action of lysozyme on the glucosamine residues of the cell wall, indicating true spheroplast formation. The photosynthetic apparatus became more pronounced with extended treatment with lysozyme.
COMPARATIVE ULTRASTRUCTURE OF THE PRIMARY NUCLEUS IN BRYOPSIS AND ACETABULARIA1,2
Authors: Burr Frances A. , West John A. 
Published: August 2007

SUMMARYThe fine structure of the primary nucleus in Bryopsis hypnoides was compared with that of the primary nucleus in Acetabularia calyculus and Batophora oerstedii. In Bryopsis the mature primary nucleus contains a peripheral reticulum composed of 4–6 layers of 200 A diameter fibrils. The nuclear membrane has numerous nuclear pores that are located adjacent to the openings in the layers of the reticulum. Each nuclear pore is constituted of peripheral globular elements and a central granule. Although pores of similar structure are present in the nuclear envelope of Acetabularia and Batophora, a fibrillar reticulum is absent.
OBSERVATIONS ON THE FINE STRUCTURE OF DICTYOCHA FIBULA EHRENBERG. II. THE PROTOPLAST1
Authors: Van Valkenburg Shirley D. 
Published: August 2007

SUMMARY Dictyocha fibula in exponential phase cultures displays a range of morphological variants of which the “sunburst” is most common. In this form, the perinuclear cytoplasm (perikaryon) contains an average of 72 dictyosomes, assorted vesicles, mitochondria, endoplasmic reticulum, and ribosomes. Cytoplasmic processes, globose to irregular, extend on fine cytoplasmic strands from the perikaryon into an extensive, viscous wall, structureless in electron micrographs except for scattered electron‐opaque leaflets near the perikaryon. Mitochondria with tubular cristae occur within the globose process and occasionally within the connecting strands. Chloroplasts, with 3‐disk lamellar bands and with pyrenoids not crossed by lamellae, are confined to the cytoplasmic processes in the sunburst from. A structure which may be the “flagellum” occasionally occurs attached to the perikaryon. However, no flagellar structures containing microtubules, nor flagellar root structures, have been found.
GLIDING MOTILITY IN THE BLUE‐GREEN ALGA OSCILLATORIA PRINCEPS1
Authors: Halfen Lawrence N. , Castenholz Richard W. 
Published: August 2007

SUMMARYGliding is an active movement displayed by a microorganism in contact with a solid substrate where there is no evidence of a motility organelle or of a conformational change in the organism. Gliding may be accompanied by rotations, reversals, flectional activity, and mucilage sheath production, as well as linear translation. Previous explanations of the mechanism responsible did not consider all these aspects of behavior.The gliding behavior and ultrastructure of the blue‐green alga Oscillatoria princeps Vaucher were examined. O. princeps has a maximum observed gliding rate of 11.1 μm/sec. The trichomes can glide in either longitudinal direction following rapid and occasionally frequent reversals. Right‐handed trichome rotation was always observed, which means that any surface point on these trichomes traces a 60‐deg right‐handed helix. A mucilage sheath envelopes the moving trichomes. The rate of gliding was reduced by viscous substrates, extreme pH, lysozyme, DNP, and cyanide, while sustained darkness had no inhibitory effect.Ultrastructurally, the cell wall is composed of an L‐1 layer which is 10 nm thick and often ill‐defined. The L‐2 layer which is outside this is 200 nm thick and participates in septum formation. The L‐3 layer is outside the L‐2 and is continuous over the trichome surface. The L‐4 “membrane” lies outside the L‐3 layer. Grazing surface sections and freeze‐etch replicas show a parallel and tight array of 6–9 nm wide continuous fibrils in the cell wall on the surface of the distinctive L‐2 layer. Isolated wall fragments were tightly coiled inside out with the fibrils on the inside. The angle of orientation for the fibrils was to the right in a helix with a pitch of 60 deg. O. animalis, a blue‐green alga with a movement tracing a left‐handed helix, showed a similar array of fibrils oriented in a left‐handed helix with a pitch of 60 deg.It is proposed that gliding is produced by unidirectional waves of bending in the fibrils which, act against the sheath or substrate, tints displacing the trichome.
OBSERVATIONS ON THE GENUS BLIDINGIA (CHLOROPHYTA) IN CALIFORNIA1
Authors: Norris James N. 
Published: August 2007

SUMMARYThe green algal genus Blidingia (Ulvales), reported for the first time in California only 4 years ago, is now found to be fairly widely distributed there as B. minima (Nägeli ex Kützing) Kylin var. minima. B. minima var. subsalsa (Kjellman) Seagal is now recorded for California. Ulva vexata Setchell and Gardner [Enteromorpha vexata (Setch. & Gardn.) Doty] is reduced to varietal status as B. minima var. vexata, and is reported, to be found in 2 ecological forms. Forms with expanded, ulvoid blades are common to exposed localities and is the form described by Setchell & Gardner. Smaller, narrower, enteromorphoid forms are found near river mouths and are the kind referred to by Doty. There are many intermediate forms of this variety.Characters which are used to separate Blidingia from Enteromorpha are critically evaluated.
COMPARATIVE ULTRASTRUCTURE OF CULTURED SPECIES OF TREBOUXIA1,2
Authors: Fisher K. A. , Lang N. J. 
Published: August 2007

SUMMARYFive species of cultured Trebouxia—T. anticipata, T. decolorans, T. erici, T. gelatinosa, and T. impressa—were examined with the electron microscope. A comparative examination of their pyrenoids revealed pyrenoglobuli associated with single pyrenoid thylakoids. The pyrenoids of T. decolorans, T. erici, and T. gelatinosa possess single thylakoids that cross or deeply penetrate the pyrenoid matrix and are often disposed in parallel arrays. T. anticipata possesses both single and double pyrenoid thylakoids within the matrix. T. impressa possesses vesiculate invaginations of thylakoid membranes into the pyrenoid matrix.The phycobiont. T. erici was examined in detail at the light and electron microscopic levels for pyrenoid alterations associated, with varied environmental regimes and with cell division. A greater amount of starch is present in cells grown in organic culture at 215 lux light intensity than in cells of similar size grown at 1075 or 3600 lux. Pyrenoglobuli are present throughout the life cycle and occur both in aplanospores and in zoospores.
DIVISION SYNCHRONY IN PRIMARY CULTURES OF AN ENDOZOIC DINOFLAGELLATE1
Authors: Franker Colin K. 
Published: August 2007

SUMMARYDivision cysts of zooxanthellae harbored by Anthopleura elegantissima were isolated from random host‐associated populations by their preferential attachment to plastic surfaces. By selecting cysts at similar stages in the cell cycle, synchronous division, excystation, and daughter cell reencystment were obtained in a medium enriched with amino acids. The interval of DNA synthesis in a single growth cycle was determined by pulse‐labeling with radioactive thymidine. Analysis of the sequence of morphologic changes within such cycles suggested that the initial selection procedure isolates G2 cells. The transit time from first generation G2 division cysts to subsequent reentry into G2 was about 70 hr.
STIMULATORY PROPERTIES OF FILTRATE FROM THE GREEN ALGAHORMOTILA BLENNISTA.II. FRACTIONATION OF FILTRATE1,2
Authors: Monahan Thomas J. , Trainor Francis R. 
Published: August 2007

SUMMARYThis investigation reports on the fractionation of filtrate from the green algaHormotilablennista known to contain autostimulatory properties. Acid, basic, and volatile acid filtrate extracts reduced the lag time ofH. blennistaat low concentrations. Whole filtrate did not express those lag time reducing capacities which were demonstrated in filtrate extracts. Glycolic acid was identified in both the acid and volatile acid extracts. Growth rate stimulation could not be demonstrated with any filtrate extract. Stimulatory properties of filtrate were shown to be dialyzable and heat labile. It was suggested that heat‐labile low molecular weight organic extracellular products are responsible for the growth rate stimulatory property of filtrate. Although dialysis and heat treatments of filtrate removed growth rate stimulation, filtrate properties capable of extending final population levels were retained. High molecular weight heat‐stable extracellular products appear to be at least partially responsible for these extended growth levels.
MICROMORPHOLOGY OF THE PERIPLAST OF CHROOMONAS SP. (CRYPTOPHYCEAE)1,2
Authors: Gantt E. 
Published: August 2007

SUMMARYAn ultrastructural examination of the periplast of Chroomonas sp. revealed a surface pattern composed of rows of plate areas. The plate areas are delineated by a series of ridges, which emanate from a common line at the posterior cell end, and lateral grooves which intersect the anterior‐posterior ridges. Small ejectosomes (trichocysts) are generally located at the intersection of the lateral grooves and the ridges. Size of the plate areas varies, being smallest at the posterior and anterior ends and largest in the midregion of the cell. The average plate area is 1 μ in length and 0.7 μ in width. In section the periplast is seen to consist of 3 intimately attached layers of which the middle (plasma membrane) layer is continuous with the gullet region, flagella, and ejectosome chambers. Trypsin digestion resulted in the disappearance of the inner and outer layers, and in the loss of periplast stiffness.
PERIDINIUM GREGARIUM, A NEW SPECIES OF DINOFLAGELLATE1,2
Authors: Lombard Eugene H. , Capon Brian 
Published: August 2007

SUMMARYA dinoflagellate has been found in tidepools on the coast of the Palos Verdes Peninsula in southern California. It is described as a new species, Peridinium gregarium. In the tidepool habitat, great numbers of the organism form cloud‐like masses held together by a mucous matrix. The gregarious cloud formation seems to be shared by only one other species of dinoflagellate, Peridinium sociale (Henneguy ex Labbé) Biecheler, 1935.
PREDAEA WELDII, A NEW SPECIES OF RHODOPHYTA FROM HAWAII, WITH AN EVALUATION OF THE GENUS1
Authors: Kraft Gerald , Abbott Isabella A. 
Published: August 2007

SUMMARYA new species of Predaea (Gigartinales, Rhodophyta) is described from Hawaii. It is compared in important morphological details with other species of the genus, all of which are distributed in the subtropics. Predaea is likewise compared to the genera of Nemastomataceae, and should be included in that family. The genus Yadranella Ercegovic (Nemaliales, Rhodophyta) is placed in synonymy with Predaea.
CAPITATE APPENDAGES ON SCENEDESMUS CULTURE 16 WALLS1
Authors: Massalski Andrzej , Trainor Francis R. 
Published: August 2007

SUMMARYA capitate appendage was detected on the cell wall of Scenedesmus strain 16 with the electron microscope, using the negative staining technique. The mushroom‐like structures, from 450 to 650 mμ long, possessed an elongate stipe and a circular cap. These are attached to ridges or the cell wall of both spiny and spineless colonies.
OBSERVATIONS SUR LES BESOINS EN VITAMINES DES DESMIDIÉES (CHLOROPHYCÉES‐ZYGNEMATALES)1
Authors: Tassigny Michel 
Published: August 2007

SUMMARYThe minimal nutrient requirements of 61 strains of desmids belonging to 18 different genera were investigated within 16 axenic cultures and 45 contaminated cultures. Thirty‐nine strains were autotrophic: they included all 30 strains belonging to the genera Cosmarium, Staurastrum, and Micrasterias. Twenty‐two strains were auxotrophic; they included all 14 strains belonging to the genus Closterium. Of the 22 auxotrophic strains, 13 required only vitamin B12; the specific requirements of the other 9 strains were not determined.