bluuebunny/crossref_metadata_2025_split huggingface dataset:
OBSERVATIONS ON THE STRUCTURE OF SOME FORMS OF GOMPHONEMA PARVULUM KÜTZ. III. FRUSTULE FORMATION1
Authors: Dawson Penelope A. 
Published: August 2007

SUMMARY Gomphonema parvulum Kütz. was investigated by electron microscopy for details of frustule formation.An expansion of the cell along the pervalvar plane occurs prior to cell division. After nuclear division the organelles are, separated into 2 entities, either by division or by dispersion. The cell divides into 2 halves by the invagination of the plasmalemma which is derived from Golgi vesicular activity. When cytoplasmic cleavage, is complete, the Golgi actively produces electronlucent vesicles which collect and coalesce beneath the. plasmalemma to form the silicalemma around the silicon deposition vesicle. The endoplasmic reticulum is also closely associated with this vesicular activity. The vesicle gradually expands and becomes extremely electron dense as silica is deposited within it—first in the region, followed by the mantle edge.When the valve is mature, Golgi vesicles collect and fuse to form the silicalemma of the first girdle band. The first girdle band becomes aligned against the mantle edge on completion, by the “sloughing off” of the external silicalemma and plasmalemma. The second and third bands are formed, individually in a similar manner. Separation of the 2 daughter cells commences at the apical pole and progresses to the basal pole. The plasmalemma and external silicalemma are “sloughed off” so that the 2 cells can separate. The inner segment of the silicalemma becomes the new plasmalemma of the daughter cell.
THE HETEROTROPHIC CAPABILITIES OF CYCLOTELLA MENEGHINIANA1
Authors: Lylis J. C. , Trainor F. R. 
Published: August 2007

SUMMARY Cyclotella meneghiniana grew heterotrophically in darkness when glucose in concentrations from 5 mg/liter to 10 g/liter was provided. The other compounds tested did not support growth. However, in continuous light (300 ft‐c) growth wax not enhanced if glucose wax provided. Under diurnal conditions of light (300 ft‐c) approximately 12–14 hr of darkness were required to observe the enhancement effects of glucose. Uptake studies with labeled glucose indicated that uptake is not dependent on glucose, but that it occurs only at low light intensities. Cells required 12–14 hr of darkness to develop the uptake system.
OBSERVATIONS ON THE EUGLENOID COLACIUM WITH SPECIAL REFERENCE TO THE FORMATION AND MORPHOLOGY OF ATTACHMENT MATERIAL1
Authors: Rosowski James R. , Kugrens Paul 
Published: August 2007

SUMMARYCertain taxonomic features of Colacium Ehrb. are evaluated from field, clone, and literature studies. A main character, morphology of the attachment material, is shown to be partially nutritionally controlled: stalks and cushion holdfasts are produced in soil‐water but rarely in plain Euglena medium; ferric and manganouns compounds influence the, formation of stalks in C. vesiculosum; single clones of C. vesiculosum produce holdfast characteristics of C. arbuscula, C. steinii, C. sideropus, and C. simplex when grown in soil‐water medium. Stalk formation is rare in C. vesiculosum but common in C. mucronatum and Colacium sp. (from the rectum of damselflies). Some questionable negative observations, incompleteness of certain species descriptions, and overlapping of species characteristics lead us to believe that C. sequabile, C. stentorinum, C. calvum, C. multoculata, C. elongatum, C. ovale, C. arcuatum, C. cyclopicola, and C. pyrenophorum = C. vesiculosum. Our C. vesiculosum attached to Mougeotia and Volvox tertius, suggesting that the epiphytic species of Colacium, C. epiphyticum, and C. parasiticum need to be studied in clonal culture to determine if they have substrate specificity, and if they represent valid species. Recommendations are made for identifying and naming species.
CHLOROPHYLL, NITROGEN, AND PHOTOSYNTHETIC PATTERNS DURING GROWTH AND SENESCENCE OF TWO BLUE‐GREEN ALGAE1,2
Authors: Daley Ralph J. , Brown S. R. 
Published: August 2007

SUMMARYA standardized, multiflask, batch culture system was developed to study the processes of algal senescence in Anacystis nidulans and Phormidium molle Gom, var. tenuior W. et G. West. Growth data over a 3‐year period gave reproducible and comparable time‐course curves.Although A. nidulans is unicellular and P. molle filamentous, the patterns of change with age were similar. Mean logarithmic doubling times and carbon yields were, respectively, 6.9 hr and 390 mg C/liter for A. nidulans and 7.2 hr and 710 mg C/liter for P. molle. Chlorophyll concentration and photo‐synthetic capacity per unit carbon rose rapidly during the logarithmic phase to maximum levels in either late log phase (P. molle) or early linear phase (A. nidulans), then fell throughout the declining growth phase to low levels in the stationary phase. Nitrate was rapidly exhausted from the medium during the period of logarithmic growth and stoichiometrically converted to particulate organic form; very little subsequent fixation of molecular nitrogen occurred. The phycocyanins were rapidly destroyed during the logarithmic phase while the carotenoids remained relatively constant throughout the whole growth period and then slowly declined. Preliminary electron micrographs showed a progressive deterioration in cellular ultrastructure, especially a reduction in the number of photosynthetic thylakoids, commenting in the linear growth phase.Analysis of the results suggests that occurrence of linear growth kinetics and termination of culture growth were caused by exhaustion of nitrate. The observed decreases in chlorophylls, phycocyanins, and photosynthetic capacity during active culture growth show that senescence effects may not be, as assumed, restricted to the stationary phase of growth.
CELL DIVISION IN BULBOCHAETE. I. DIVISIONS UTILIZING THE WALL RING1
Authors: Pickett‐Heaps Jeremy D. 
Published: August 2007

SUMMARYCell division in Bulbochaete closely resembles that of Oedogonium, particularly in the involvement of a ring in cell elongation, the structure of the spindle, the existence of complex kinetochores, and the method of cross‐wall formation using a phycoplast. Some minor differences between the 2 genera are found. In contrast to Oedogonium, the filaments of Bulbochaete are branched. The site and direction of branching are initially determined by a subtle change in the morphology of the wall, which invariably (if the cell divides) leads to the asymmetrc division that forms a hair cell (these events will be described separately). The position of the wall ring is always precisely determined as in Oedogonium, by the position of a very characteristic weakening in the wall; once a hair cell has been formed, this weakening is located underneath the hair, and all subsequent division and elongation in the cell subtending the hair will necessarily be in the direction of that hair (ie, thereby forming and increasing the length of a branch).
SPECIES OF OCEANIC DINOFLAGELLATES IN THE GENERA DISSODINIUM AND PYROCYSTIS: INTERCLONAL AND INTERSPECIFIC COMPARISONS OF THE COLOR AND PHOTON YIELD OF BIOLUMINESCENCE1
Authors: Swift Elijah , Biggley William H. , Seliger Howard H. 
Published: August 2007

SUMMARYWe have examined aspects of the bioluminescence of 5 clones of Dissodinium, 1 clone of Pyrocystis acuta, 4 clones of Pyrocystis fusiformis, and 5 clones of Pyrocystis noctiluca. All clones produced the same color bioluminescence with an intensity peak near 474 nm. The in vivo emission spectra of these clones agreed with those previously determined, for 4 other species of marine dinoflagellates. The amount of light emitted by the dinoflagellates in scotophase when mechanically stimulated to exhaustion was determined for most of the clones. The largest species, P. noctiluca and P. fusiformis, emitted 37–89 × 109 photons cell−1 and 23–62 × 109 photons cell−1, respectively, about a thousand, times as much light as Gonyaulax species. Pyrocystis acuta emitted 3–6 × 109 photons cell−1. Three of the 5 clones of Dissodinium were bioluminescent. The range for 3 clones was 5–13 × 109 photons cell−1. All 5 clones of Dissodinium are morphologically distinct. Both the clones of Dissodinium and Pyrocystis produced much higher numbers of photons per cell nitrogen (ca. 7–50 times) than Gonyaulax polyedra or Pyrodinium bahamense. The data suggested that enzyme turnover occurred in the reactions producing light during mechanical stimulation of Dissodinium and Pyrocystis species.
HYDROGEN SULFIDE PRODUCTION BY SYNECHOCOCCUS LIVIDUS Y52‐s1
Authors: Sheridan Richard P. 
Published: August 2007

SUMMARYUnder anaerobic conditions and in the absence of CO2, the thermophilic blue‐green alga Synechococcus lividus Y52‐s, evolved hydrogen sulfide in both darkness and light. The mechanism of this process was investigated and compared with photo‐ and dark reductions in organisms representing several phyla. The photoproduction of H2S from either sulfate or thiosulfate was inhibited by 3‐(3,4‐dichlorophenyl)‐1, 1‐dimethyl urea (DCMU) and carbonyl m‐chlorophenyl‐hydrazone (m‐Cl‐CCP). The inhibitory effect of DCMU showed the requirement for photosystem II as electron donor. Inhibition by m‐Cl‐CCP also implicated ATP as an energy source. Monofluoroacetate partially inhibited photoproduction of H2S. This indicated that oxidative metabolism may act us a source of electrons to reduce the photooxidant under certain conditions. Thiosulfate acts only as electron acceptor and is reductively cleaved to S= and SO3=. Thiosulfate and sulfate appeared to replace CO2 in the light and O2 in darkness as electron acceptors. The phosphorylation uncouplers dinitrophenol and m‐Cl‐CCP stimulated dark H2S production.
GERMINATION AND ATTACHMENT OF ZYGOTES OF HIMANTHALIA ELONGATA (L.) S. F. GRAY1
Authors: Ramon Edith 
Published: August 2007

SUMMARYGerminating zygotes of Himanthalia elongata (L.) S. F. Gray have a prolonged stage free from rhizoids. The spherical zygote flattens when settling on a substratum and a rim‐like structure develops at the periphery of the flattened base. Numerous rhizoids appear simultaneously 5–7 days after fertilization. The possible significance of the germling's shape and structure in relation to attachment is discussed.
THE MARINE DIATOM ETHMODISCUS REX: ITS MORPHOLOGY AND OCCURRENCE IN THE PLANKTON OF THE SARGASSO SEA1,2
Authors: Swift Elijah 
Published: August 2007

SUMMARYLiving cells of the diatom Ethmodiscus rex (Rat‐Iray) Wiseman & Hendey 1953 were found in the plankton of the southern Sargasso Sea. Apparently, this is the first report, of E rex from the plankton of the Atlantic Ocean. Scanning electron microscopy of peroxide‐cleaned frustules revealed, some new morphological features for this species. When viewed, from inside the frustule, the puncta appear as rimmed pits. From outside the frustule, they appear to he shallow depressions with a small opening at the bottom. The so‐called mucous tubules in the center of the valve were seen from the out side to be elongate slits and from the inside as obliquely directed flattened cylinders which cap the tubes.
MITOSIS AND CYTOKINESIS IN COLEOCHAETE SCUTATA1
Authors: Marchant Harvey J. , Pickett‐Heaps Jeremy D. 
Published: August 2007

SUMMARYIncrease in the size of thalli of C. scutata was achieved by division and growth of the marginal cells. During mitosis, the nuclear envelope disintegrated and the daughter nuclei remained widely separated after telophase. The plane of cytokinesis in the marginal cells was either along a radius of the discoidal thalli or parallel to their circumference For radial divisions, this alga utilized a phragmoplast typical of higher plants, and a modified phragmoplast when dividing circumferentially. The phylogenetic implications of these findings are discussed.
TWO NEW SPECIES OF TOLYPELLA(CHARACEAE) FROM NORTH AMERICA1,2
Authors: Sawa Takashi 
Published: August 2007

SUMMARYTwo new species of the genus Tolypella (Characeae)–T. boldii Sawa sp. nov. and T. canadensis Sawa sp. nov.–were discovered in Texas, U.S.A., and Ontario, Canada, respectively. The species are recognized as additional members to the section Acutifolia because of the small and conical branchlet end cell and the oospore with a single basal impression. However, they differ from all the members previously described in the genus by the frequent and unique development of a terminal antheridium at the fertile branchlet node. A new and unexpected chromosome number of n = 8 for the genus was determined in both species, which, renders additional support to the conclusion that they represent a new taxonomic group in the section. The plants are described in detail in order to clarify some important morphological features which have been loosely interpreted by previous workers. Relationships between the new species and other members of the section are analyzed.
THE EFFECT OF SELENITE ON THE PHYSIOLOGICAL AND MORPHOLOGICAL PROPERTIES OF THE BLUE‐GREEN ALGA PHORMIDIUM LURIDUM VAR. OLIVACEA1
Authors: Sielicki Margarete , Burnham Jeffrey C. 
Published: August 2007

SUMMARY Phormidium luridum cultures were treated with sodium selenite in concentrations ranging from 10−6 M to 10−2 M. In contrast to the increasing culture turbidity of control and 10−6 M selenite cultures, the turbidity of the other selenite cultures declined in proportion to time and selenite concentration. Chlorophyll extraction revealed similar results. Photosynthetic activity was inhibited within 6 hr in all cultures except control and 10−6 M selenite. Phormidium at concentrations greater than 10−6 M selenite showed a gradual loss of the bright green color and turned semitransparent. Cell‐associated granules of reduced selenium were observed at higher selenite concentrations. Other structural changes observed were the presence of intracellular and intercellular spaces, spheroplast formation, and gradual cell lysis. Protein analyses of total cell samples and supernatant fractions confirmed cellular breakdown of selenite‐treated algal cells.
A PHYSIOLOGICAL INVESTIGATION OF THE HOT SPRING DIATOM, ACHNATHES EXIGUA GRÜN1
Authors: Fairchild Eugene , Sheridan Richard P. 
Published: August 2007

SUMMARYThe diatom Achnanthes exigua, isolated from Alhambra North Hot Spring, showed a maximum growth rate of 2 doublings per day at 40 C; the maximum and minimum temperatures at which growth occurred was 44 and 10 C, respectively. The optimal temperature for respiration was 40 C, whereas the optimum temperature for photosynthesis was 42 C. Respiration exhibited greater thermotolerance than either growth or photosynthesis. Light saturation occurring at comparatively low light intensities suggests that the unialgal diatom culture may represent a selected shade‐adapted organism.
INTERACTIONS OF PHYTOPLANKTERS CULTURED FROM A POLLUTED SALINE LAKE, ONONDAGA LAKE, NEW YORK1,2,3
Authors: Sze Philip , Kingsbury John M. 
Published: August 2007

SUMMARYTwo‐membered cultures of 3 phytoplankters isolated from Onondaga Lake, grown in defined media under laboratory conditions, were analyzed by electronic particle counts and statistical methods to determine antagonistic, neutral, or stimulatory relationships. Over the range studied (exponential phase of growth, nutrients not limiting), growth of Staurastrum paradoxum is markedly reduced in the presence of Chlamydomonas sp. Growth of Chlamydomonas is not affected by presence of Staurastrum. The initial concentration of Staurastrum has an effect on its subsequent growth. The initial concentration of Chlamydomonas does not have an effect on its subsequent growth nor that of Staurastrum. These effects are not mediated by a filterable factor (unless highly labile) or by competition for a nutrient. They resemble, and perhaps describe, fluctuations of these species in the lake.
GLUCOSE TRANSPORT SYSTEMS AND GROWTH CHARACTERISTICS OF BRACTEACOCCUS MINOR1,2
Authors: Sheath Robert G. , Hellebust Johan A. 
Published: August 2007

SUMMARYBracteacoccus minor grows on glucose both in the dark and in the light. However, the growth rates at 50 ft‐c or higher in the presence of glucose are considerably lower than those in inorganic media at the same intensities. The lowered growth rates in the presence of glucose appear to be related to changes in metabolism toward increased production of storage carbohydrates. Glucose shortens the length of the lag phase at high light intensities and increases the length of the exponential phase at all light intensities, resulting in very high cell yields compared to cultures grown in inorganic media.B. minor has 2 transport systems for glucose: (1) a high affinity system, KS=1 × 10−5 M, which is formed in the dark in the absence of external glucose; and (2) a low affinity system, KS=5 × 10−4 M, which appears to be constitutive. At high concentrations of glucose there is also significant free diffusion of glucose into the cells. The glucose analog, 3‐O‐methyl glucose, is also taken up by the inducible system, but at a lower rate than glucose. It is Acumulated, about 2000 times in a 20‐min incubation period, indicating active transport. Cycloheximide inactivates the high affinity system to the same extent as high light intensities, and also prevents induction of this system in the dark. Rates of photosynthesis are inversely correlated to glucose uptake rates over a range of light intensities of pre‐incubation. The possession of a light‐regulated high‐affinity transport system as well as a constitutive low‐affinity system for glucose is probably of competitive advantage to this alga in the soil environment.
MITOSIS AND CYTOKINESIS IN PLATYMONAS SUBCORDIFORMIS, A SCALY GREEN MONAD1
Authors: Stewart Kenneth D. , Mattox Karl R. , Chandler Cynthia D. 
Published: August 2007

SUMMARYScaly green monads are often placed in a separate class, Prasinophyceae, and have been considered to be among the most, primitive of green algae. Platymonas possesses rhizoplasts which resemble sarcomeric structures. At prophase, extranuclear spindle micro‐tubules emanate from a granular region which appears to arise through dissolution or dispersion of the rhizoplasts. It is probable that the rhizoplasts are largely consumed during the formation of the spindle and only small fragments are left at metaphase. The rhizoplasts can be seen again at telophase but are short at this stage. The basal bodies are not at the spindle poles but remain at their interphase position. The interzonal spindle collapses early at telophase, and shortly thereafter cleavage microtubules appear. These microtubules extend from the region of the basal bodies to the posterior of the cell. The events of cell division are compared with these events in other green algae and in Ochromonas. The functional and phylogenetic significance of the observations is discussed.
NEGATIVE PHOTOTROPISM OF THE HAPTERA OF ALARIA ESCULENTA (LAMINARIALES)1,2
Authors: Buggeln Richard G. 
Published: August 2007

SUMMARYThe “root‐like” haptera of the holdfast of Alaria esculenta (L.) Grev. display a negative phototropic curvature only when unilaterally irradiated with blue (432 nm) and green (552 nm) wavelengths.
ALGAL EXCRETION AND BACTERIAL ASSIMILATION IN HOT SPRING ALGAL MATS1
Authors: Bauld John , Brock Thomas D. 
Published: August 2007

SUMMARYBenthic 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

SUMMARYCapitular 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

SUMMARYThe 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.
SOME CHARACTERISTICS OF THE SPERM ATTRACTANT FROMOEDOGONIUM CARDIACUM1
Authors: Machlis Leonard , Hill Gerry G. C. , Steinback Katherine E. , Reed Walfred 
Published: August 2007

SUMMARYA 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.