bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE CELL WALL OFCOSMARIUM BOTRYTIS12
Authors: Lott John N. A. , Harris Graham P. , Turner Christine D. 
Published: August 2007

SUMMARYThe cell wall ofCosmarium botrytiswas studied through the use of the freeze‐etch technique. The cell wall consists of many thin layers. Fracturing along one layer reveals the positioning of the wall sculpturing, wall pores, and wall microfibrils. The individual microfibrils are grouped together in bands of parallel oriented fibrils. The different bands of parallel microfibrils were apparently arranged at random angles with regard to each other. Small particles may also be present in the cell walls.The cell wall pore unit ofCosmarium botrytiswas studied through the use of scanning, freeze‐etching, and thin sectioning techniques. The pore sheaths, on the outside of the cell wall, form a collar around the mouth of each pore. The pore sheath is composed of needle‐like fibrils radiating outward from the pore. A pore channel traverses the cell wall and leads to a complex pore bulb region between the cell wall and the plasmalemma. The pore bulb contains many small fibrils which radiate toward the plasmalemma from a number of net‐like fibril layers which in turn merge into a very electron dense region near the base of the pore.
ENDOGENOUS LEVELS OF INDOLE‐3‐ACETIC ACID IN SYNCHRONOUS CULTURES OF CHLORELLA PYRENOIDOSA12
Authors: Grotbeck Larry , Vance B. Dwain 
Published: August 2007

SUMMARYEndogenous levels of indole‐3‐acetic acid were mesaured in synchronous cultures of Chlorella pyrenoidosa (TX‐7‐11‐05). The cultures were synchronized by alternating light:dark periods of 15:9 hr at a temperature of 40 ± 1 C. After 2 synchronous cycles the cultures were exposed to a low light treatment of 350 ± 100 ft‐c. The time to incipient cell division under these conditions was 6 hr and 15 min. Samples were taken at 3 sampling periods during the low light treatment period:low light 0 hr (LL0); low light 3 hr (LL3); and low light 6:15 hr (LL6:15). The algal extracts were analyzed by a fluorometric procedure which measured the indole‐α‐pyrone product formed by the action of the trifluoracetic acid‐acetic anhydride reagent with IAA.The IAA levels increased gradually from the autospore stage (5.19 μg × 10−4/mg dry wt) to the adolescent stage (7.13 μg × 10−4/mg dry wt) and more rapidly when approaching the ripened adult stage (14.55 μg × 10−4/mg dry wt). The mean percentage increase from autospore to adolescent was 36.9%, and from adolescent to ripened adult 104.6%. The total percentage increase from autospore to adult was 180.3%. Levels of IAA were 2 times higher just prior to division than in the autospore stage.
SCHIZOMERIS—A GROWTH FORM OF STIGEOCLONIUM TENUE (CHLOROPHYTA:CHAETOPHORACEAE)1
Authors: Campbell Ella O. , Sarafis V. 
Published: August 2007

SUMMARY Schizomeris leibleinii Kütz. was found as an ecophene of Stigeoclonium tenue (Ag.) Kütz. in Centennial Lake, Palmerston North, New Zealand. The Schizomeris form occurred in autumn when the water was polluted by a large number of ducks. Sampling of the plant population of the lake and culture work showed that S. tenue has a high degree of polymorphism. Other forms of it which developed both in the lake and in culture were indistinguishable from Protoderma Kütz. emend. Borzi, from Uronema Lagerheim, or from Pearsoniella Fritsch and Rich, respectively.
l‐THREONINE DEAMINASE IN MARINE PLANKTONIC ALGAE. II. DISULFIDE AND SULFHYDRYL GROUP REQUIREMENTS OF ENZYME ACTIVITY IN TWO CRYPTOPHYTES1
Authors: Antia Naval J. , Kripps Robert S. , Desai Indrajit D. 
Published: August 2007

SUMMARYThe “biosynthetic”l threonine (deaminating) dehydratase of 2 cryptophytes (Chroomonas salina and Hemiselmis virescens) showed sensitive inhibition from all thiols tested (dithiothreitol, cysteine, etc.) but no effect from ascorbic acid or reduced NAD. By contrast, the enzyme activities from 5 noncryptophyceaen unicellular algae (2 cyanophytes, 1 rhodophyte, 1 diatom, 1 chlorophyte) were generally not affected by any of these reagents. The thiol reagent inhibition of the cryptophyte enzymes (1) achieved saturation with 60–70% reduction in activity, (2) was considerably reduced by pretreatment of the enzymes with l‐threonine and l‐isoleucine, and (3) was partially reversed by subsequent treatment with arsenite and exposure to air. It was deduced that such inhibitions were caused by thiol‐specific reduction of enzyme‐protein disulfide groups essential for the full expression of activity and that these groups were susceptible to ready reductive cleavage and oxidative restoration. This disulfide requirement, unique to the cryptophytes, may be the first recorded case of such a property of threonine dehydratase from all forms of life hitherto studied. The additional activity requirement of the cryptophyte enzymes for sulfhydryl groups (which requirement was common to all the algal enzymes) was confirmed (1) by the study of their sensitivity to inhibition from mercurials and disulfide‐sulfhydryl exchanging reagents, and (2) by the partial reversal of these inhibitions from subsequent treatment with dithio‐threitol. Both cryptophyte enzymes were densitized to feedback inhibition from l‐isoleucine by prior exposure to subinhibitory concentrations of HgCl2 or dithiodipyridine.
ASEXUAL DEVELOPMENTAL PATTERNS OF THE DIATOM STAURONEIS ANCEPS IN CULTURE123
Authors: Hostetter H. P. , Hoshaw Robert W. 
Published: August 2007

SUMMARYDuring several months under controlled growth conditions, cell division in the diatom Stauroneis anceps resulted in a gradual decrease in length as predicted by the Macdonald‐Pfitzer hypothesis. Cells of a clone decreased in average length from 35 to 17 μ. The smallest cell observed measured 12 μ. Cells longer than 26 μ typically had capitate ends. As the cells became shorter, there was a gradual decrease in this capitate configuration with the smallest cells being oval in outline. The estimated increment of size reduction due to cell division in the clone was 0.1 μ per division. This value is dependent on the assumption of random division. Populations with cells less than 28 μ in length showed an increase in valve aberrations, but these cells continued to reproduce. A cell 13 μ long and similar to the smallest specimen of the clone was observed from a core sample with fossil specimens of S. anceps.
TOXICITY OF COPPER TO THALASSIOSIRA PSEUDONANA IN UNENRICHED INSHORE SEAWATER1
Authors: Erickson Stanton J. 
Published: August 2007

SUMMARYToxicity of copper to T. pseudonana (formerly Cyclotella nana, clone 13‐1) wax examined in inshore seawater using a 96‐hr bioassay method. Raw unenriched seawater wax filtered through a 0.22‐μ membrane filter and then pasteurized, for 30 min at 60 C. Following this treatment, samples contained 0.68–1.14 μg Cu/liter. Copper was added as the chloride in 5‐μg increments over the range of 5 to 30 μg/liter (about 0.1–0.5 μM). Population densities, mean cell, volume, and 14C bicarbonate uptake were measured.Population growth, and 14C uptake by T. pseudonana displayed inhibition over the entire range of added copper. Growth rate constant (k) of T. pseudonana decreased with increasing copper concentration and during the course of growth at each concentration. Correspondingly, mean cell volumes increased with copper concentration and time. Copper toxicity varied in different water samples. The presence of decomposed natural plankton and detritus decreased toxicity. In the absence of enrichment, bacteria had little effect on copper toxicity. H exults were influenced by glassware treatment, collection and storage of seawater, and absence of enrichments.
CELL DIVISION IN COSMARIUM BOTRYTIS1
Authors: Pickett‐Heaps Jeremy 
Published: August 2007

SUMMARYCell division in Cosmarium is described. Premitotic cells are very dense; the semicells, previously appressed to one another, separate slightly during entry into prophase. This separation coincides with deposition of a girdle of new wall material around the isthmus, where the 2 semicells are joined. Micro‐tubules, abundant around the isthmus wall during interphase, all disappear during prophase; meanwhile, other microtubules proliferate outside the nuclear envelope. By metaphase, the nucleolus has dispersed, although remnants of it persist. The nuclear envelope breaks up, but some membranes coat metaphase chromosomes. The spindle, while being typical, is somewhat multipolar; microtubules, usually associated with elements of endoplasmic reticulum, are oriented toward numerous regions in the poles. During anaphase and telophase, these spindle tubules become increasingly directed toward a few discrete foci, and they persist after telophase. Meanwhile, the septum grows from the girdle of wall material to bisect the cell.After cytokinesis, some microtubules reappear near the isthmus, but only adjacent to the older, non‐expanding semicell wall. Cell expansion then takes place, during which the nucleus, ensheathed in a complex microtubular system, moves into the forming semicell. Later, the chloroplast follows the nucleus and its 2 pyrenoids elongate and divide. When semicell expansion is complete, the chloroplast cleaves adjacent to the isthmus. The nucleus, now apparently not associated with microtubules, concurrently moves back into the isthmus.Continuous deposition of primary wall material accompanies cell expansion. Wall materials are apparently secreted as aggregates (perhaps derived from the contents of vesicles) adjacent to the plasmalemma, whose fibrous components become increasingly oriented in the outer layers of the wall by stretching. Late in semicell formation, this deposition ceases and during further expansion, the semi‐cell develops a pattern of warts and ridges. Secondary wall deposition under the primary wall then follows, matching this pattern of ornamentation. In addition, numerous plugs of amorphous material capped by specialized regions of the plasmalemma, traverse the entire thickness of the secondary wall which becomes further thickened at these particular sites. The amorphous plugs presumably are eroded away later to form the mucilage pores of the vegetative cells. The wall microtubules gradually become more symmetrically arrayed around the isthmus as this new secondary wall thickens.These observations are discussed in comparison with other work on morphogenesis in desmids.
THE EFFECT OF GROWTH ILLUMINATION ON THE PIGMENTATION OF A MARINE DINOFLAGELLATE12
Authors: Mandelli Enrique F. 
Published: August 2007

SUMMARY Amphidinium klebsii cultures grown under different light intensities exhibited similar chlorophyll a content per cell.Among the accessory pigments, chlorophyll c concentration decreased slightly in cells exposed to increasing light intensities up to 0.129 ly/min. The concentration of the 2 major xanthophylls present in A. klebsii cells–peridinin and diadinoxanthin–however, varied according to the light background of the cells. Some biochemical pathways in the formation of peridinin in dinoflagellates are discussed.
THE ANTIBACTERIAL SUBSTANCES OF THE MARINE ALGA STICHOCHRYSIS IMMOBILIS (CHRYSOPHYTA)12
Authors: Berland Berigitte R. , Bonin Daniel J. , Cornu Alain L. , Maestrini Serge Y. , Marino Jean‐Paul 
Published: August 2007

SUMMARYTwo substances with antibacterial activity have been concentrated from the culture medium of Stichochrysis immobilis before senescence occurred, and purified, by a Sephadex G‐25 filtration followed by 2‐dimensional thin‐layer chromatography on Merck F‐254 silica gel plates. One of the substances is obviously a peptide; 11 different amino acids are linked in a 30 amino acid molecule (MW 3400). It was not possible to assign a chemical group to the second substance (MW ≃ 2600); it may be related to “humic acids” (Kalle's gelbstoff). Growth of the most sensitive bacteria was completely inhibited by 20‐fold, or higher, concentrations of substances from the algal culture filtrate (assuming no loss of substances during the concentration processes). The 54 strains of test bacteria were of various origins, though mostly isolated from algal cultures or obtained directly from the marine environment.
INHIBITION OF PHOTOSYNTHESIS IN ALGAE BY DIMETHYL SULFOXIDE1
Authors: Cheng K. H. , Grodzinski B. , Colman Brian 
Published: August 2007

SUMMARYPhotosynthetic oxygen evolution and 14CO2 fixation by 3 blue‐green algae, Anabaena flos‐aquae, Oscillatoria sp., and Anacystis nidulans, and 1 green alga, Chlorella pyrenoidosa, were: inhibited by dimethyl sulfoxide at concentrations above 1%.
VIRUS‐LIKE PARTICLES AND NUCLEAR INCLUSIONS IN THE RED ALGA PORPHYRIDIUM PURPUREUM (BORY) DREW ET ROSS1
Authors: Chapman Russell L. , Lang Norma J. 
Published: August 2007

SUMMARYUltrastructural examination of the unicellular red alga Porphyridium purpureum has revealed cytoplasmic and nuclear inclusions termed concentrosomes. These bodies are morphologically distinct from the irregular membranous inclusions previously reported by others as concentric bodies. In thin section, the morphology of concentrosomes varies from a simple set of 3 or 4 (or rarely 5) concentrically arranged, electron‐opaque, circular profiles to elongate, sinuous forms and particulate aggregations, the majority clearly within the nucleus but separated front the nucleoplasm by what appears to be the nuclear envelope. Although simple concentrosomes may be observed in either the cytoplasm or the nuclei, the more elaborate forms occur only in nuclei. In addition to the concentrosomes, subspherical to polygonal virus‐like particles of approximately 40 nm diameter have been observed in P. purpureum. These particles are characterized by an electron‐opaque perimeter that, in approximately equal numbers, surrounds an “empty” or an opaque core. Dense arrays of the virus‐like particles appear in the cytoplasm but not in the nuclei. Similarities between certain forms of the concentrosomes and the virus‐like particles are suggestive of an ontogenetic relationship. The infrequency with which either the concentrosomes or the virus‐like particles are observed has hampered attempts to verify a developmental sequence or to establish unequivocally the infectious nature of the virus‐like particles.
ALGAL EXCRETION OF 14C‐LABELED COMPOUNDS AND MICROBIAL INTERACTIONS IN CYANIDIUM CALDARIUM MATS1
Authors: Belly R. T. , Tansey M. R. , Brock T. D. 
Published: August 2007

SUMMARYAcid spring effluents are often covered with mats of the eucaryotic phycocyanin‐containing alga. Cyanidium caldarium. The primary bacterial component of such mats is an acidophilic strain of Bacillus coagulans, and the primary fungal component is Dactylaria gallopava. Because of the limited species diversity, C. caldarium mats appeared to be an excellent system for studying algal excretion and various microbial interactions in nature. From 2 to 6% of the NaH14CO3 taken up by natural or laboratory populations of the alga was excreted as 14C‐labeled materials. The maximum excretion occurred at temperature, light, and pH values optimum for NaH14CO3 uptake. However, when excretion was expressed as a percentage of NaH14CO3 uptake, a higher percentage of the radioactivity was excreted at nonoptimal conditions for NaH14CO3 uptake. Fungal biomass was directly proportional to algal density, but bacterial numbers varied widely and did not correlate with algal numbers. The bacterial and fungal components could be grown in mixed culture with either growing C. caldarium cultures or in an extract prepared, by healing algal cells.
MITOSIS, CYTOKINESIS, THE DISTRIBUTION OF PLASMODESMATA, AND OTHER CYTOLOGICAL CHARACTERISTICS IN THE ULOTRICHALES, ULVALES, AND CHAETOPHORALES: PHYLOGENETIC AND TAXONOMIC CONSIDERATIONS1
Authors: Stewart Kenneth D. , Mattox Karl R. , Floyd Gary L. 
Published: August 2007

SUMMARYThe results of previous research and a present survey of some of the cytological characteristics of 18 additional genera and 34 additional species are presented and discussed from the viewpoint of phylogenetic and taxonomic significance. A preliminary attempt is made to place these, algae, in 4 orders on the basis of comparative cytology, and in particular on the basis of variation in mitosis and cytokinesis and the distribution of plasmodesmata. Consideration is given to the evolution of the phragmoplast and to the hypothesis that the Chaetophorales are related to the ancestry of land plants.
PHYCOLOGICAL NOTES. H. EUGLENA MYXOCYLINDRACEA SP. NOV.12
Authors: Bold Harold C. , Frank J. MacEntee S. J. 
Published: August 2007

SUMMARYA previously undescribed species of Euglena, E. myxocylindracea, sp. nov., is described from soil in a garden and in a while pine woods in Pike County, Pa. In addition to the, type, an organism (No. 457) in the Culture Collection of Algae. Indiana University, hitherto designated E. viridis var. terricola. is transferred to E. myxocylindracea as var. terricola. Differences such as the usual absence of an emergent flagellum, or the presence of an extremely short one (ca. 3.5–4 μ), and the dominance of a palmelloid state in a variety of liquid and solid culture media in which the cells secrete dichotomously branching slimy cylinders distinguish the new species from E. viridis.
ENVIRONMENTAL CONTROL OF GAMETOGENESIS IN LAMINARIA SACCHARINA. IV. IN SITU DEVELOPMENT OF GAMETOPHYTES AND YOUNG SPOROPHYTES1,2
Authors: Hsiao Stephen I. C. , Druehl Louis D. 
Published: August 2007

SUMMARYMeiospores of Laminaria saccharina labeled with a fluorescent stain were put into the sea and recovered at frequent intervals. They developed into gametophytes which produced gametes throughout the year. Antheridia were produced earlier than oogonia. Gametogenesis was slowest during the late autumn and early winter. On the basis of nutritional studies and the seasonal distribution of nutrients, it was concluded that the rate of gametogenesis was not due to nutrient deficiency but most likely to light.Production of macroscopic sporophytes appeared to be limited by survival of microscopic sporophytes rather than gametogenesis. Macroscopic sporophytes became evident during the late winter and autumn. The greater light and perhaps higher temperatures of summer were suggested as agents limiting macroscopic sporophyte production during this period.
A DESCRIPTION OF HAPLOZOON AXIOTHELLAE N. SP., AN ENDOSYMBIONT OF THE POLYCHAETE AXIOTHELLA RUBROCINCTA12
Authors: Siebert Arthur E. 
Published: August 2007

SUMMARYA new parasitic dinoflagellate, Haplozoon axiothellae sp. nov., is described from the intestine of the marine polychaete Axiothella rubrocincta. The parasites are 40–175 μm long with 2–26 cells arranged in single or double rows. Two cytoplasmic inclusions previously unknown in this genus are described. The first is globular and varies in size, while the second is approximately 2 μm long and peanut‐shaped. The function and composition of the inclusions are unknown. Nuclear structure and karyokinesis are apparently different from those of typical dinoflagellates.
TWO MORPHOLOGICAL TYPES OF PARTICULATE INCLUSIONS IN MARINE DINOFLAGELLATES12
Authors: Pokorny Kathryn Stein , Gold Kenneth 
Published: August 2007

SUMMARYTwo species of laboratory‐reared nonbioluminescent dinoflagellates, Gymnodinium splendens (photo‐synthetic) and Crypthecodinium cohnii (hetero‐trophic), were observed to posses abundant quantities of randomly moving structures, which are contained in vacuoles. When viewed with the electron microscope, 2 shapes of regular, geometric particles, here termed particulate inclusions, were observed. The morphology of the particulate inclusions is described.
KINETICS OF SILICON‐LIMITED GROWTH IN THE MARINE DIATOM THALASSIOSIRA PSEUDONANA HASLE AND HEIMDAL (=CYCLOTELLA NANA HUSTEDT)1,2
Authors: Guillard Robert R. L. , Kilham Peter , Jackson Togwell A. 
Published: August 2007

SUMMARYThe half‐saturation constant (K8) for growth and the maximum growth rate (μmax) were determined for 2 clones of Thalassiosira pseudonana (=Cyclotella nana) under conditions in which external silicon concentrations controlled growth. The estuarine clone (3H) had a higher half‐saturation constant and maximum growth rate (K8= 0.98 μM Si; μmax= 3.6 divisions/day) than the clone from the Sargasso Sea (K8= 0.19 μM Si; μmax= 2.1 divisions/day). The K8 values for each clone are such that the silicate levels found at certain times in both the Sargasso Sea and the coastal regions are rate limiting to growth, hence can be of significance to plant production and to species succession. The yield data are consistent with the concept that growth rate and cellular silicon content vary together in silicon‐limited cultures.
DIATOM ASSOCIATIONS IN YAQUINA ESTUARY, OREGON: A MULTIVARIATE ANALYSIS1
Authors: McIntire C. David 
Published: August 2007

SUMMARYA cluster analysis and a principal components analysis were performed to examine the degree to which the diatom flora of Yaquina estuary can be partitioned into discrete associations and to relate the composition of the flora to selected physical properties of the estuary. The species composition of the diatom flora during the winter was more closely associated with salinity and intertidal exposure them in the summer. A cluster of freshwater taxa obtained for the winter data was the most conspicuous diatom association defined by the cluster analysis. Although taxa within a cluster had more similar distributions than taxa from different clusters, there was considerable variation in the distributions of marine and brackish water taxa within a multispecies cluster.
SOME THOUGHTS ON NUTRIENT LIMITATION IN ALGAE1
Authors: Droop M. R. 
Published: August 2007

SUMMARYAn empirical relation relating specific growth, rate in steady state systems to nutrient status with respect to more than one nutrient simultaneously is proposed, based on 3 experimentally verifiable postulates: (1) that uptake depends on the external substrate concentration; (2) that growth depends on the interval substrate concentration; and (3) in a steady state system specific rate of uptake (in the absence of significant, excretion) is necessarily the product of the specific growth rate and internal substrate concentration. The implications of this model are discussed in particular in respect to the concept of luxury consumption and Liebig's law of minimum. Some aspects of uptake in transient situations are also discussed.
ULTRASTRUCTURE OF ZOIDOGENESIS IN UNILOCULAR ZOIDOCYSTS OF SEVERAL BROWN ALGAE1
Authors: Loiseaux S. 
Published: August 2007

SUMMARYSeveral different stages of the development of unilocular zoidocysts of small brown algae—Elachista fucicola, Hecatonema streblonematoides, Pylaiella littoralis—are observed by electron microscopy.1. A slow growing phase is seen, during which nuclei and pheoplasts become associated by pairs and divide together, vacuoles and physodes are excreted through the plasmalemma, and Golgi bodies liberate vesicles with fibrillar material identical to the growing cell wall fibers. Mitochondria and Golgi bodies are concentrated under the very sinuous plasmalemma.2. A very short spatial reorganization phase follows, during which organelles disperse between the nuclei‐pheoplast pairs, cleavage vesicles appear, and flagella start developing. New pyrenoids formde novo.3. The latter phase is followed by a longer maturation phase. Cleavage vesicles fuse and separate zoids grow as flagella. Mastigonemes formed in the endoplasmic reticulum are finally found in vesicles of a special Golgi body at the base of the anterior flagellum. They are liberated in parallel rows at the base of the already developed flagella by these Golgi's vesicles, and attach, on the flagella by an unknown process. Excretion of a mucilaginous substance takes place as the stigmas formde novo.4. The ripe, swollen zoidocysts burst open, liberating the whole gelatinous mass. Naked zoids swim and settle on a substrate, retracting their flagella before excreting a new cell wall.