bluuebunny/crossref_metadata_2025_split huggingface dataset:
GROWTH OF BLADES OF NEREOCYSTIS LUETKEANA (PHAEOPHYTA) IN DARKNESS 1
Authors: Kain (Jones) Joanna M. , Norton Trevor A. , Montegut Ann E. 
Published: April 2007

ABSTRACT Short term measurements were made of the relative growth rate of the fast growing portions of blades of Ncreocystis luetkeana (Merl.) Post. et Rupr. during exposure to natural daylight and during prolonged darkness. Growth was only slightly, but significantly, faster during the 12 h of daylight than during the 12 h that included 8 h of darkness. Clearly considerable growth occurred at night. In blades amputated 1 cm beyond the zone measured, growth was slower during both night and day. In continuous darkness growth continued for up to 12 days. It was not influenced by amputation of distal blade tissue but it was increased by severance from the bulb and stipe. A mean volume increase of 50% of the blade tissue was recorded. While the organic content decreased, the drop was half that required to support the increase in volume. There was some evidence against translocation. It is possible that cellular biochemical rearrangements allow a light‐independent increase in organic material.
MORPHOLOGY AND TAXONOMY OFMERISTIELLAGEN. NOV. (SOLIERIACEAE, RHODOPHYTA)1
Authors: Gabrielson Paul W. , Cheney Donald P. 
Published: April 2007

ABSTRACTEucheuma acanthocladum (Harvey) J. Agardh, E. gelidium (J Agardh) J. Agardh, E. echinocarpumAreschoug andE. schrammii(P. et H. Crouan) J. Agardh from the tropical and warm temperate waters of the western Atlantic Ocean and Caribbean Sea are transferred to a new genus, Meristiella. Meristiellaexhibits the following Unique combination of characters among genera in the Solieriaceae: (1) rotated periaxial cells, (2) a loosely filamentous medulla. (3) an auxiliary cell complex, (4) Single and twin connecting filaments and (5) spinose cystocarps composed of a central, small‐celled placentum, based on its reproductive features, Meristiella.is assigned to the tribe Agardhielleae. Culture experiments and herbarium studies provide evidence thatE, gelidiumandE. acantghocladumare conspecific. Lectotypes are designated for the included species.
UDPGLUCOSE PYROPHOSPHORYLASE ACTIVITY IN THE DIATOM CYCLOTELLA CRYPTICA. PATHWAY OF CHRYSOLAMINARIN BIOSYNTHESIS 1
Authors: Roessler Paul G. 
Published: April 2007

ABSTRACT UDPglucose pyrophosphorylase activity was detected in cell‐free extracts of the diatom Cyclotella cryptica TI3L Reimann, Lewin and Guillard. When assayed in the direction of UDPglucose formation, the enzyme had maximal activity at pH 7.8 and was stimulated by Mg2+and Mn2+ions. 3‐Phosphoglycerate and inorganic phosphate had little effect on enzymatic activity, and the enzyme was relatively insensitive to feedback inhibition from UDPglucose (K, > I millimolar). A glucan was formed from UDP‐[14C]glucose in cell‐free extracts of C. cryptica. This glucan had a median molecular weight of 4600 (as determined by gel filtration chromatograbhy) and could be hydrolyzed by laminarinase. Partial acid hydrolysis of the glucan resulted in the formation of glucose and laminaribiose. but not cellobiose. These results suggest that the synthesis of chrysolaminarin (the major storage carbohydrate of diatoms) occurs via the activity of UDPglucose pyrophosphorylase. followed by glucosyl transfer from UDPglucose to the growing β‐(1–3)‐linked glucan.
PARMALES, A NEW ORDER OF MARINE CHRYSOPHYTES, WITH DESCRIPTIONS OF THREE NEW GENERA AND SEVEN NEW SPECIES1,2
Authors: Booth Beatrice C. , Marchant Harvey J. 
Published: April 2007

ABSTRACTA new order, Parmales, in the Chrysophyceae has cells with siliceous walls made up of round, triradiate and sometimes oblong plates all fitting edge to edge. In the new family, Octolaminaceae, cell walls have eight plates. Cell walls in the new genus Tetraparma have four round plates and four triradiate plates. Cell walls in the new genus Triparma have three round plates of equal size, one larger round plate, one triradiate plate and three oblong plates. In the new family, Pentalaminaceae, cell walls have three round and two triradiate plates. A total of seven new species and four subspecies are described from subarctic Pacific and Antarctic waters.
A POLYPLOID SPECIES COMPLEX IN SPIROGYRA MAXIMA (CHLOROPHYTA, ZYGNEMATACEAE), A SPECIES WITH LARGE CHROMOSOMES1
Authors: Hoshaw Robert W. , Wells Charles V. , McCourt Richard M. 
Published: April 2007

ABSTRACTA species complex in Spirogyra consists of the series of filament morphotypes of various ploidal levels arising from an original morphotype within a clonal culture or in nature. A clonal culture of filaments identified as Spirogyra maxima (Hassall) Kützing produced several morphotypes, i.e. filament types of distinctly different widths and ploidal levels. Banding patterns and satellites were visible on chromosomes stained at mitotic prophase and metaphase. The original culture of S. maxima contained filaments averaging 127 μ wide. Vegetative cells of the original culture contained six large chromosomes (>4 μ long), identifiable as three distinct pairs based on banding patterns and presence of satellites: (1) one pair of short chromosomes (ca. 5.0 μ); (2) one pair of long chromosomes (ca. 8.0 μm); and (3) a second pair of long chromosomes (ca. 9.0 μm) including a nucleolar organizing region and satellite. A larger morphotype averaging 175 μm in width contained 12 chromosomes, with two pairs of short chromosomes and four pairs of long chromosomes (satellites were usually indistinct). Aneuploid chromosome numbers ranging from 5 to 13 were observed in a few cells. Binucleate and trinucleate cells were also observed. A twobanded chromosome fragment was observed in a few cells with 6 chromosomes and a few cells with 12 chromosomes. The variety of morphotypes derived in this study could be identified as four different species of Spirogyra by conventional taxonomic criteria. The banding patterns and satellites on chromosomes suggest that three pairs of homologous chromosomes are present in filaments of the original clonal culture and that these filaments are themselves autopolyploid (diploid) descendants of ancestral form with a base chromosome number of x = 3.
FLAGELLAR ROOTS AND THE RESERVOIR CYTOSKELETON OF COLACIUM LIBELLAE (EUGLENOPHYCEAE)1
Authors: Willey Ruth L. , Wibel Ronald G. 
Published: April 2007

ABSTRACTThe three flagellar roots of Colacium Ehrenberg give rise to the three microtublar bands of the reservoir cytoskeleton. The dorsal root (DR) originates at the basal body (bb1) of the emergent flagellum. It is initiated on the left side of the cell, runs toward the right side under the posterior end of the reservoir and thence anteriorly in a spiral path over the dorsal surface of the reservoir until it terminates on the left side of the eyespot. Along its length, it appears to initiate a dorsal band (DB) which forms the major dorsal portion of the reservoir cytoskeleton—the dorsal microtubules (DMT). Two roots originate at the basal body (bb2) of the non‐emergent flagellum. The ventral root (VR) runs up the left side of the cell and initiates the band of microtubules which forms part of the presumptive vestigial cytopharynx. Therefore, it forms the reinforcing microtubules (MTR) of Colacium. The intermediate root (IR) forms the para‐reservoir microtubules (PMT). Flagellar root correlation with the reservoir cytoskeletal bands strengthens their homologies with the bodonid bands and further supports the hypothesis that the euglenoids are derived from the kinetoplastid flagellates.
THE APICAL MERISTEM OF SPLACHNIDIUM RUGOSUM (PHAEOPHYTA)1
Authors: Clayton Margaret N. , Shankly Christine M. 
Published: April 2007

ABSTRACTThe meristem of Splachnidium rugosum consists of a central apical cell surrounded by a region of actively dividing cells, many of which bear hairs. Conceptacle initials are scattered throughout the surface layer of the meristematic region. Conceptacle initials and apical hairs differentiate adjacent to the apical cell. The apical cell and the conceptacle initials are distinctive, pear‐shaped cells possessing similar cytological features that are consistent with significant metabolic activity. They have a nucleus surrounded by dictyosomes, a stellate chloroplast, mitochondria, and numerous vesicles and physodes. When the apical cell is damaged as a result of experimental manipulation, growth ceases. It is inferred that the apical cell controls cell division in the meristematic region and also the differentiation of conceptacle initials and apical hairs. The apical meristems of Splachnidium and species of the Fucales have several important features in common, including the growth‐regulatory role of the apical cell and the process of conceptacle initiation. The taxa may possibly have a common evolutionary origin. The problematic and unresolved taxonomic status of Splachnidium is discussed.
SYMBIOSIS IN THE PLANKTONIC FORAMINIFER, ORBULINA UNIVERSA, AND THE ISOLATION OF ITS SYMBIOTIC DINOFLAGELLATE, GYMNODINIUM BÉII SP. NOV.1
Authors: Spero Howard J. 
Published: April 2007

ABSTRACTThe symbiotic association of the spinose planktonic foraminifer, Orbulina universa, with the dinoflagellate, Gymnodinium béii sp. nov., was examined with light and electron microscopy, and the symbiont was isolated into unialgal culture. The intact association is characterized by a diurnal movement of the symbionts from the distal regions of the spines during the day, to perialgal vacuoles within the host cytoplasm at night. This diurnal migration involves a daily endo‐ exocytotic cycle.Gymnodinium béii is non‐motile and spindle‐shaped within the host, whereas it is motile and gymnodinoid in shape when in culture. Ultrastructural examination revealed two or more stalked pyrenoids penetrated by lamellae, a typical dinokaryon nucleus and no trichocysts. A distinct ‘flange’projects over the sulcus from the hypocone. The swimming behavior of this dinoflagellate was characterized by intermittent darting events. Swimming speeds during a dart reached velocities of 770 μm. s−1 as compared to a mean, non‐darting swimming velocity of 126 μm. s−1. Gymnodinium béii is eurythermal and division rates ranged between 0.16 and 0.65 divisions day−1 for culture temperatures between 6.5 and 25° C respectively.
THALLUS MORPHOLOGY AND SPORE FORMATION IN CULTURED ERYTHROCLADIA IRREGULARIS ROSENVINGE (RHODOPHYTA, BANGIOPHYCIDAE)1
Authors: Gargiulo Gaetano M. , Masi Flora De , Tripodi Giacomo 
Published: April 2007

ABSTRACTThe discoid thallus of Erythrocladia irregularis is the result of a pattern of cellular divisions expressed by mono‐and endospores; the latter are described for the first time in Erythrocladia. In nutrient enriched growth conditions the discoid thallus becomes a shapeless aggregate of unicells with a wrinkled wall surface, whose plane of division is unpredictable. The cells are able to produce monosporangia with a curved wall or they form eight‐celled endosporangia. Chloroplasts have an internal pyrenoid, as is characteristic of the Erythropeltidaceae.The observation that E. irregularis can form either a colonial cluster of unicells or a discoid thallus would lead to the assignment of the genus to the Porphyridiales; however, since this order is reserved to organisms in which only the unicellular organization can be expressed, it is suggested to maintain Erythrocladia in the Erythropeltidales.
LIGHT AND ELECTRON MICROSCOPY OF PYRENOIDS AND SPECIES DELIMITATION INVOLVULINA(CHLOROPHYTA, VOLVOCACEAE)1
Authors: Nozaki Hisayoshi , Hara Yoshiaki , Kasaki Hideo 
Published: April 2007

ABSTRACTThe appearances of pyrenoids in the vegetative cells of Volvulina steinii Playfair and V. pringsheimii Starr were observed in detail by light and electron microscopy in relation to the culture age to clarify the taxonomic relationship between the two species. In V. pringsheimii, the pyrenoids were always present in the bottom of the cupshaped chloroplasts and their gross morphology did not vary in relation to the culture age, while those of V. steinii appeared de novo and developed as the culture aged. In 24‐h cultures of V. steinii, pyrenoids were not observed in the chloroplasts. In 48‐h cultures, a pyrenoid matrix developed apparently de novo in the brim of the cupshaped chloroplast. Subsequently, starch grains appeared around the pyrenoid matrix in 72‐h cultures. The volume of the matrix and the associated starch grains increased and tubular channels entered into the pyrenoid matrix in 96‐h cultures. In addition, the pyrenoid in the parental chloroplast of V. pringsheimii divided and was distributed to each daughter cell during cell divisions in daughter colony formation, while the parental pyrenoid of V. steinii did not divide and went to one of the daughter cells. Therefore, these two species can be clearly distinguished by the differences in the position of pyrenoids in the cupshaped chloroplasts and stability of pyrenoid appearance in relation to the culture age, as well as in the fate of parental pyrenoids during daughter colony formation.
AN ULTRASTRUCTURAL SURVEY OF CRYPTOMONAD PERIPLASTS USING QUICK‐FREEZING FREEZE FRACTURE TECHNIQUES1
Authors: Kugrens Paul , Lee Robert E. 
Published: April 2007

ABSTRACTA quick‐freezing technique for freeze fracturing was used to determine periplast plate types in 20 cryptomonads. With this technique cells are frozen so rapidly that major artifacts are eliminated. We propose that periplast plates are attached to the cell membrane by intramembrane particles (IMP's), consequently plate shapes are outlined by IMP distribution in fractured membranes. Round to oval, sometimes slightly angular, plates occur in Cryptomonas ovata, Cryptomonas tetrapyrenoidosa, Cryptomonas parapyrenoidifera, Cryptomonas obovata, Cryptomonas erosa and two unidentified species of Cryptomonas; large rectangular plates occur in Chroomonas pochmannii, Chroomonas coerulea and Hemiselmis sp.; small rectangular plates were found in Cryptomonas sp. (Strain SDB); square to slightly rounded plates occur in Cryptomonas chrysoidea and a single continuous plate or sheet, perforated by ejectisome pores, was observed in Cryptomonas caudata, Cryptomonas rostratiformis, Cryptomonas marssonii, Cryptomonas platyuris, Cryptomonas curvata, Cryptomonas ozolini, Chilomonas paramecium and Rhodomonas sp. Oval and square plates are described for the first time in Cryptomonas. Plate IMP's may be morphologically modified in size and shape, depending upon their location in relation to the plate, the plate ridges, and ejectisome chambers. Conformational changes in plate shapes, to form hexagons or polygons, may be induced when cells are subjected to fixation, desiccation, cryoprotectants or centrifugation.
EVIDENCE FOR A COMMON EVOLUTIONARY ORIGIN OF LIGHT‐HARVESTING FUCOXANTHIN CHLOROPHYLL a/c‐PROTEIN COMPLEXES OF PAVLOVA GYRANS (PRYMNESIOPHYCEAE) AND PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1
Authors: Fawley Marvin W. , Morton Sharon J. , Stewart Kenneth D. , Mattox Karl R. 
Published: April 2007

ABSTRACTA fucoxanthin‐chlorophyll a/c‐protein complex has been isolated from the prymnesiophyte Pavlova gyrans. Thylakoid membranes were treated with the mild anionic detergent sodium taurodeoxycholate followed by sucrose density gradient centrifugation. The brown fraction produced by this procedure was treated with Triton X‐100 followed by a second sucrose density gradient centrifugation. A brown fraction isolated from this gradient was shown to be a light‐harvesting complex nearly identical to that which is present in the diatom Phaeodactylum tricornutum. The complexes from the two organisms have nearly identical absorption and flourescence spectra, both complexes contain fucoxanthin and two other carotenoids, both contain four polypeptides of similar molecular weights, and polypeptides from both complexes cross react with antibodies raised to polypeptides of the Phaeodactylum tricornutum complex. Results suggest a common evolutionary origin for these light‐harvesting complexes, in apparent contrast to the great differences in cell structure between prymnesiophytes and diatoms.
Gene profile in periodontal ligament cells and clones with enamel matrix proteins derivative
Authors: Barkana Idit , Alexopoulou Eleni , Ziv Shoshi , Jacob‐Hirsch Jasmin , Amariglio Ninette , Pitaru Sandu , Vardimon Alexander D. , Nemcovsky Carlos E. 
Published: April 2007

AbstractAim: Evaluate enamel matrix proteins derivative effect on gene expression profiles in cultured human periodontal ligament cell population and its clones.Material and Methods: Human periodontal ligament (PDL) cells were explanted. Cell cloning was performed and clones classified into fibroblastic (FB) and mineralized tissue forming (MTF) according to their capacity to express alkaline phosphatase and form mineralized tissue. All cell cultures were grown for 7 days, with and without enamel proteins added to the medium. Following RNA extraction, expression profiling was performed by hybridization with a DNA micro‐array. Selected genes differed from the control at a significant level smaller than p<0.01.Results: Enamel proteins induced major qualitative changes in mRNA expression in all PDL cell populations, differently affecting the entire PDL cell population and its clones. In the entire PDL cell population, enamel proteins significantly enhanced PDL cell function, with a general effect on enhanced cell functional metabolism.Conclusions: Enamel proteins enhanced gene expression responsible for protein and mineralized tissue synthesis in the entire PDL population. In the MTF clones, nucleic acid metabolism, protein metabolism and signal transduction related genes were up‐regulated, while in the FB clones, up‐regulated genes were related to cell adhesion, nucleic acid metabolism and signal transduction.
Osmotic adjustment of chickpea (Cicer arietinum) is not associated with changes in carbohydrate composition or leaf gas exchange under drought
Authors: Basu P.S. , Berger J.D. , Turner N.C. , Chaturvedi S.K. , Ali M. , Siddique K.H.M. 
Published: April 2007

AbstractGenetic differences in osmotic adjustment (OA) have been reported among chickpea (Cicer arietinum) cultivars. In this study eight advanced breeding lines (ABLs) derived from a cross between CTS 60543 (high OA) and Kaniva (low OA) and Tyson (medium OA) and Kaniva, along with the parents, were evaluated for OA, leaf carbohydrate composition and leaf gas exchange under dryland field conditions in India. The water potential (WP) decreased to lower values (less than −2.5 MPa) in Tyson, M 110 and M 86 than in the other genotypes. With decrease in WP, OA increased by 0.5 MPa in Kaniva and CTS 60543 to 1.3 MPa in M 55. As the decrease in WP varied with genotype, when OA was regressed against WP M 39 and M 55 had greater increases in OA with decrease in WP than the remaining nine genotypes, including the parents. As WP decreased, leaf starch content decreased while total soluble sugars, hexoses and sucrose increased: the decrease in starch was much smaller in M 93 and M 129 than in Tyson and M 51, but genotypic differences could not be detected in the increase in total sugars, hexoses or sucrose. The rates of photosynthesis and transpiration decreased as the WP became more negative, but M 129 reached low rates of photosynthesis (2 μmol m−2 s−1) and transpiration at a WP of −1.7 MPa, whereas Tyson reached the same low rate at −2.4 MPa. While OA varied among the chickpea genotypes, the differences were not associated with the changes in carbohydrate composition or the rates of gas exchange at low values of WP. Further, the degree of OA of the 11 genotypes was not the same as when they were selected for differences in OA under rainout shelter conditions in the field in Australia, suggesting that OA may show poor stability depending upon the stress level, location or physiological stage of the plant. This suggests that OA is not a valuable drought‐resistance trait to select for in chickpea breeding programmes.
Photosynthesis and transpiration of tomato and CO2 fluxes in a greenhouse under changing environmental conditions in winter
Authors: Tartachnyk I. I. , Blanke M. M. 
Published: April 2007

AbstractResponses of tomato leaves in a greenhouse to light and CO2 were examined at the transient stage at the end of winter, when both photoperiod and irradiance gradually increase. Additionally, CO2 fluxes were calculated for a greenhouse without supplementary lighting and without CO2 enrichment based on CO2 sinks (plant photosynthesis) and CO2 sources (plant and substrate respiration). In January, tomato leaves in the greenhouse showed low photosynthesis with a maximum assimilation of 6–8 μmol CO2 m−2 s−1, a quantum yield of 0.06 μmol CO2 μmol−1 photosynthetic active radiation (PAR) and a low light compensation point of 26 μmol PAR m−2 s−1, a combination which classifies them as shade leaves. In February, tomato leaves increased their light compensation point to 39 μmol PAR m−2 s−1 and quantum yield to 0.08, the former indicating the adaptation to increased irradiance and photoperiod. These tomato leaves increased their transpiration from 0.4 to 0.9 in January to ∼2 mmol H2O m−2 s−1 in February. Both photosynthesis and transpiration were primarily limited by light but neither by stomatal conductivity nor by CO2. In January, light response of photosynthesis, dark respiration and transpiration were negligibly affected by increasing CO2 concentrations from 600 to 900 ppm CO2 under low light conditions, indicating no benefit of CO2 enrichment unless light intensity increased. In February, tomato leaves were photoinhibited at inherent greenhouse CO2 concentrations on the first sunny day; this photoinhibition was further enhanced by an increased CO2 concentration of 1000 ppm. CO2 fluxes in the greenhouse appeared strongly dependent on solar radiation. After exceeding the light compensation point in the morning, greenhouse CO2 concentrations decreased by 58 or by 110 ppm CO2 h−1 on a sunny day in January or February and by 23 ppm on overcast days in both months. Calculated per overall tomato canopy, plant photosynthesis contributed 42–50% to the morning CO2 depletion in the greenhouse. Dark respiration of tomato leaves was ∼2 μmol CO2 m−2 s−1 in January and ∼3 μmol CO2 m−2 s−1 in February. This dark respiration resulted in rises of 15 and 17 ppm CO2 h−1 at night in the greenhouse compartment and was identified as primary source of CO2. Respiration of the substrate used to grow the plants, which produced 7.3 ppm CO2 h−1, was identified as secondary source of CO2. The combined plant and substrate respiration resulted in peaks of up to 900 ppm CO2 in the greenhouse before dawn.