bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antispasmodic effects of essential oil ofPterodon polygalaeflorusand its main constituent β‐caryophyllene on rat isolated ileum
Authors: Leonhardt Valeria , Leal‐Cardoso José H. , Lahlou Saad , Albuquerque Aline A.C. , Porto Romulo S. , Celedônio Natalia R. , Oliveira Ariclecio C. , Pereira Renalison F. , Silva Leidiane P. , Garcia‐Teófilo Taylena M.N. , Silva Anna P.F.S. , Magalhães Pedro J.C. , Duarte Gloria P. , Coelho‐de‐Souza Andrelina N. 
Published: August 2010

AbstractThis study investigates the effects of essential oil ofPterodon polygalaeflorus(EOPP) and β‐caryophyllene (β‐CAR). EOPP and β‐CAR relaxed the basal tone of ileum smooth muscle in a concentration‐dependent manner (IC50s = 394.35 ± 62.12 and 68.65 ± 9.51 μg/mL respectively), an effect that was unaltered by hexamethonium,L‐nitroarginine methyl ester or indomethacin. Both EOPP and β‐CAR evoked a concentration‐dependent relaxation of ileum pre‐contracted with KCl with an IC50value of 107.78 ± 10.47 and 17.35 ± 0.75 μg/mL, respectively. EOPP and β‐CAR inhibited the contractions induced by acetylcholine (ACh) and by KCl. In ileal preparations, the CaCl2‐induced contractions were reduced by EOPP (300 μg/mL) and β‐CAR (100 μg/mL). Furthermore, CaCl2‐induced contractions were also reduced by EOPP (300 μg/mL) and β‐CAR (100 μg/mL) in ileal preparations pretreated with ACh under Ca2+‐free condition and in the presence of verapamil. EOPP (100 and 300 μg/mL) and β‐CAR (30 and 100 μg/mL) reduced the ACh‐induced contractions of isolated rat ileum under Ca2+‐free conditions. In the presence of high KCl and Ca2+‐free conditions, EOPP (300 μg/mL) and β‐CAR (100 μg/mL) reduced the contractions induced by barium. A similar effect was also observed with verapamil. It is concluded that (i) β‐CAR is an important constituent involved in the myorelaxant and antispasmodic effects induced by EOPP; (ii) the inhibitory effect on intestinal contractility is myogenic and seems mainly mediated through an intracellular mechanism. However, the ability of EOPP and β‐CAR to decrease Ca2+influx through cytoplasmic membrane could not be discounted.
Effects of sphingosine‐1‐phosphate and sphingosylphosphorylcholine on intracellular Ca2+ and cell death in prostate cancer cell lines
Authors: Mulders A. C. M. , Nau S. , Li Y. , Michel M. C. 
Published: August 2010

SummaryThe sphingolipid metabolites sphingosine‐1‐phosphate (S1P) and sphingosylphosphorylcholine (SPC) can be involved in cellular growth and apoptosis, by both receptor‐dependent and ‐independent mechanisms. We investigated the role of S1P and SPC in intracellular Ca2+ elevation, cell proliferation and cell death in DU 145 and PC3 hormone‐refractory prostate cancer cell lines. S1P and SPC increased intracellular Ca2+ levels, most likely in a receptor‐independent manner. Surprisingly, both S1P and SPC did not stimulate but rather reduced cell growth through induction of apoptosis. Therefore, antagonists targeted against S1P, SPC and their receptors do not appear to be promising new approaches in the treatment of hormone‐refractory prostate cancer.
Economic production quantity model with a shifting production rate
Authors: Ben‐Daya Mohamed , Hariga Moncer , Khursheed Syed Naveed 
Published: August 2010

AbstractTypical models for determining the economic production quantity (EPQ) assume perfect product quality and perfect production processes. Deteriorating processes may affect production systems in several ways. They may decrease the quality of the items produced, cause production stoppage and breakdowns and/or reduce the production rate due to production process inefficiency. The purpose of this paper is to present an EPQ model that incorporates the effect of shifts in production rate on lot sizing decisions due to speed losses. The cycle starts with a certain production rate and after a random time, the production rate shifts to a lower value. A mathematical model to determine the optimal production policy under these conditions is developed and analyzed. Numerical examples are presented for illustrative purposes.
Voluntary Disclosure, Earnings Quality, and Cost of Capital
Authors: FRANCIS JENNIFER , NANDA DHANANJAY , OLSSON PER 
Published: August 2010

ABSTRACTWe investigate the relations among voluntary disclosure, earnings quality, and cost of capital. We find that firms with good earnings quality have more expansive voluntary disclosures (as proxied by a self‐constructed index of coded items found in 677 firms' annual reports and 10‐K filings in fiscal 2001) than firms with poor earnings quality. In unconditional tests, we find that more voluntary disclosure is associated with a lower cost of capital. However, consistent with the complementary association between disclosure and earnings quality, we find that the disclosure effect on cost of capital is substantially reduced or disappears completely (depending on the cost of capital proxy) once we condition on earnings quality. Extensions probing alternative proxies show that our findings are robust to measures of earnings quality and cost of capital, but not to other measures of voluntary disclosure. In particular, we find opposite relations for voluntary disclosure measures based on management forecasts and conference calls, and we find no relations for a press release based measure.
STRUCTURE AND COMPOSITION OF OOCYSTIS POLYMORPHA CELL WALLS ISOLATED FROM THE CULTURE MEDIUM1
Authors: Schwertner H. A. , Butcher W. I. , Richardson B. 
Published: August 2010

SUMMARY Oocystis polymorpha and possibly other algae which shed their parent‐cell walls during reproduction appear to be suitable organisms for cell wall research in that the cell walls can be readily collected from the culture medium. Electron micrographs of sectioned isolated cell walls, of the parent‐cell walls, and of the daughter cells appear to be identical, suggesting that the isolated cell walls are representative of those of the intact cell. Chemically, the cell walls of Oocystis polymorpha resemble the cell walls of Cyanidium and the chemically resistant cuticle fraction of Cladophora and Porphyra in their high nitrogen and low sugar and lipid contents. Pink carotenoids are the major lipid components of the cell walls.
SEASONAL PATTERNS OF REPRODUCTION IN NEW YORK. POPULATIONS OF CODIUM FRAGILE (SUR.) HARIOT SUBSP. TOMENTOSOIDES (VAN GOOR) SILVA1,2
Authors: Churchill A. Coolidge , Moeller Henry W. 
Published: August 2010

SUMMARYThe characteristics of reproduction in 2 New York populations of Codium fragile were investigated over nearly a 2‐yr period. Reproduction occurred by the exclusive formation of reproductive cells that germinated and developed, asexually. There was no evidence at any time that the reproductive cells fused and thus functioned as gametes.The relative abundance of the reproductive organs on plants in both populations exhibited a marked seasonal variation. New fronds first initiated reproductive organs during July and attained maximum values during the autumn. Formation of new reproductive organs did not occur during the winter and early spring, and those present slowly degenerated so that minimum values occurred during April–May. Reinitiation of reproductive organs on second‐year fronds started in May–June. It is proposed that a minimum temperature between 12 and 15 C is required for the initiation of reproductive organs and that temperatures below this range are inhibitory to their formation.
ECOLOGICAL IMPLICATIONS OF CULTURE STUDIES ON NEREOCYSTIS LUETKEANA1
Authors: Vadas Robert L. 
Published: August 2010

SUMMARYMeiospores, gametophytes grown in culture and then fragmented in a blendor, and young sporophytes of N. luetkeana, were grown at varying temperatures, light intensities, photoperiods, and densities. Vegetative growth occurred over a wider range of environmental conditions than did sexuality. Gametophytes matured at 5, 10, and 15 C but not at 20 C. Low light., 15 ft‐c (161 lux), and short day photo‐periods (8–16) inhibited or greatly retarded sexuality. Saturation intensities for sexuality occurred between 100 and 200 ft‐c (1076 and 2152 lux). Maximal rates of sexuality occurred at or above light, intensities of 3200 ft‐c hr/day on an alternating (16–8) light‐dark cycle. Light was determined to be the single most important factor in sexuality and subsequent sporophyte growth. Increased density did not affect sexuality but significantly reduced sporophyte growth. Field light intensities beneath lower canopy kelps were below minimal light requirements for gametophyte maturation. These data support, the view that light sets the lower limits on vertical distribution and that, temperature is involved in the latitudinal range of N. luetkeana. These and other studies suggest that the anomalous shallow water depth distribution of N. luetkeana in the San Juan Islands is partly the result of competition for light and not light attenuation, per se.
UTILIZATION OF DISSOLVED ORGANIC CARBON BY NATURAL POPULATIONS OF EPIBENTHIC SALT MARSH DIATOMS1
Authors: Darley W. Marshall , Ohlman Connie T. , Wimpee Barbara B. 
Published: August 2010

ABSTRACTNatural populations of pennate diatoms collected from the mudflats of a Georgia salt marsh were cleansed by differential centrifugation and tested for their ability to assimilate and respire14C‐acetate, lactate and glucose at 1 μM concentrations. A correction was made for contaminating bacterial activity. Utilization rates were measured in the light and dark and in the presence of a second substrate. Mean incorporation rates were (in pmol ·μg chl a−1· h−1± SE): acetate, 117 ± 37; lactate, 53.7 ± 20.4; glucose 13.0 ± 5.8. Using a carbon/chlorophyll ratio of 53.2 and a generation time of 48 h we calculate these algae could obtain up to 1% of their carbon heterotrophically if several usable substrates were each available at 1 μM concentrations.
OLISTHODISCUS LUTEUS(CHRYSOPHYCEAE). III. UPTAKE AND UTILIZATION OF NITROGEN AND PHOSPHORUS1
Authors: Tomas Carmelo R. 
Published: August 2010

ABSTRACTUptake and assimilation of nitrogen and phosphorus were studied inOlisthodiscus luteusCarter. A diel periodicity in nitrate reductase activity was observed in log and stationary phase cultures; there was a 10‐fold difference in magnitude between maximum and minimum rates, but other cellular features such as chlorophylla,carbon, nitrogen, C:N ratio (atoms) · cell−1were less variable.Ksvalues (~2 μM) for uptake of nitrate‐N and ammonium‐N were observed. Phosphorus assimilated · cell−1· day−1varied with declining external phosphorus concentrations; growth rates <0.5 divisions · day−1were common at <0.5 μM PO4‐P. Phosphate uptake rates(Ks=1.0–1.98 μM) varied with culture age and showed multiphasic kinetic features. Alkaline phosphatase activity was not detected. Comparisons of the nutrient dynamics ofO. luteusto other phytoplankton species and the ecological implications as related to the phytoplankton community of Narragansett Bay (Rhode Island) are discussed.
CELL DIVISION PERIODICITY IN 13 SPECIES OF MARINE PHYTOPLANKTON ON A LIGHT: DARK CYCLE1
Authors: Nelson David M. , Brand Larry E. 
Published: August 2010

ABSTRACTThe division rates of 26 clonal cultures representing 13 species of planktonic marine algae (6 diatoms, 2 flagellated chrysophytes, 2 coccolithophores, 1 cryptomonad flagellate, I dinoflagellate, 1 green alga) were determined every 2 h for 48 h during exponential growth on a 14:10 LD cycle in nutrient‐replete batch culture. Cyclic oscillations in the division rate were detectable in 22 of these clones. Of 14 diatom clones examined, four displayed nearly constant division rates throughout the LD cycle and ten showed strong periodicity favoring division during the light periods. In contrast, all other algae (12 clones) exhibited division rate maxima during periods of darkness, and clearly detectable decreases in cell number for time intervals of 4–8 h during periods of illumination. Intraspecific differences in division periodicity were found among eight clones of the diatom Thalassiosira pseudonana (Hustedt) Hasle & Heimdal and six clones of the coccolithophore Emiliania huxleyi (Lohm.) Hay & Mohler.
COLONIZATION AND STANDING CROPS OF EPILITHIC ALGAE IN THE SUSQUEHANNA RIVER, PENNSYLVANIA1
Authors: Gale William F. , Gurzynski Andrew J. , Lowe Rex L. 
Published: August 2010

ABSTRACTA SCUBA diver, using a bar‐clamp sampler, collected quantitative epilithic algae samples from artificial substrates (slate and acrylic plates) and river stones at two stations on the Susquehanna River bottom in 1974. At Falls, Pennsylvania, algal colonization on monthly plates (submerged for ca. 30 day periods) was most rapid between September and October. In winter, when algal density on cumulative plates (submerged 2–13 mo) and on stones present in the river peaked at 18,100 and 21,900 units/ mm2, respectively, colonization of clean monthly plates nearly ceased. Similar colonization patterns were observed in a portion of the river polluted by coal mine drainages (SSES), but expansion of the algae population at SSES was inhibited by iron in the effluents, and densities never exceeded 2,400 units/mm2 on stones or plates. Diatoms composed 95% of the overall standing crop at Falls and 65% at SSES.
ULTRASTRUCTURE OF THE CORALLINACEAE (RHODOPHYTA) II. VEGETATIVE CELLS OF LITHOTHRIX ASPERGILLUM1
Authors: Borowitzka Michael A. , Vesk Maret 
Published: August 2010

ABSTRACTThe ultrastructure of the calcareous red coralline alga Lithothrix aspergillum Gray and the development of the various tissue types has been studied. The sub‐apical meristematic tissue alternately produces genicular or intergenicular cells. The genicular cells rapidly elongate and their cell walls thicken and become denser as more fibrillar wall material is laid down within the cell wall. These cells contain little cytoplasm and few organelles. The inter genicular cells which elongate only slightly during development have a small vacuole and many free starch grains in the cytoplasm. The peripheral cells in each inter genicular layer remain meristematic and form a cortical cell layer over the genicular cells. These cortical cells and the apical meristematic cells are covered by small epidermal cells which have extensive cell wall ingrowths between the chloroplasts. The inter genicular cells are calcified. Although the CaCO3 is laid down within the cell walls, there is always a thin layer of CaCO3‐free organic cell wall material between the plasmalemma and the CaCO3 impregnated wall. Only the distal tips of the genicular cells are calcified. In old genicular tissues of Lithothrix, secondary deposits of CaCO3 of unknown crystallography are also found in the spaces between the cell walls. Thus there appear to be at least two mechanisms of calcification in this alga.
DEVELOPMENT OFJANCZEWSKIA MORIMOTOI(CERAMIALES) ON ITS HOSTLAURENCIA NIPPONICA(CERAMIALES, RHODOPHYCEAE)1
Authors: Nonomura Arthur M. 
Published: August 2010

ABSTRACTJanczewskia morimotoiTokida was successfully cultured from spore to reproductive maturity on its hostLaurencia nipponicaYamada. The spore penetrates the host without requirement for wound or abrasion sites, growing between host cortical cells and developing a superficial and an endophytic system simultaneously. During the juvenile period, when the parasite is nonpigmented, it differentiates a cortex and the proliferating endophytic filaments enlarge causing a displacement of layers of host cells into the parasitic tissue. Host cells contacted by cells of the parasite exhibit increased wall thickness, cytoplasmic density and vesicle formation. Pit connections between host and parasite cells were rarely observed whereas penetration of host cell walls was seen commonly. As the parasite increases in size, its cells become pigmented evenly throughout the cortex and host cells show less obvious reactions to the parasite. At this same time, the parasite develops branches and reproductive structures. Host plant segments less than 3 cm long failed to grow when infected with spores of the parasite whereas longer segments were not significantly affected by the parasite. In the absence of the host, the parasite cannot complete its development. AlthoughJ. morimotoiis well pigmented at maturity, the absence of pigmentation in the juvenile stage, penetration of host cells, and effect on host growth in culture strongly suggest that it is parasitic during at least its early development.
FEULGEN MICROSPECTROPHOTOMETRIC STUDIES OF PANDORINA MORUM AND OTHER VOLVOCALES (CHLOROPHYCEAE)12
Authors: Coleman Annette W. 
Published: August 2010

ABSTRACTThe nuclear DNA content during normal vegetative growth and division has been examined in three species of Volvocales, Chlamydomonas reinhardtii Dangeard, Pandorina morum Bory, and Volvox carteri f. nagariensis Iyengar. The results are consistent with the nuclear cycle reported in the literature for Eudorina. Nuclear DNA content does not increase during the prolonged cell growth phase. At the time of colony formation, nuclear DNA doubles, the nucleus divides, and this alternation continues until the final 2n complement of progeny nuclei is formed. The 4‐ and 8‐nucleate stages of dividing gonidia of V. carteri have a nuclear DNA content in the same range as the somatic cells; they are not polyploid or polytene. Four normal clones of Pandorina, having 2, 5 or 12 chromosomes, all had similar amounts of DNA per nucleus, suggesting that the species has a nuclear genome of fairly constant size rather than consisting of many strains representing a polyploid series. One unique clone, a hybrid with double the chromosome number of either its parents, had twice as much DNA as the normal clones. The Feulgen spectrophotometric method is sufficiently sensitive to detect 2‐fold differences in DNA content at the level of 2 × 10−13 g of DNA /nucleus, and its use avoids the complications associated with the presence of organelle DNA.
SEASONAL VARIATION IN SUN‐SHADE ECOTYPES OF PLECTONEMA NOTATUM (CYANOPHYTA)1
Authors: Sheridan Richard P. 
Published: August 2010

ABSTRACTClonal cultures of the thermophilic alga Plectonema notatum Schmidle were grown from cells collected in winter from the surface and subsurface zones of the cell mat in Jerry Johnson Hot Spring, Idaho. Both surface and subsurface clones exhibited light saturation curves and concentrations of photosynthetic pigments typical of ecotypes highly adapted to shade environments. These winter clones were compared to surface and subsurface clones collected during summer months. This comparison illustrates the seasonal rotation of ecotypes. The shade adapted winter surface and subsurface types dominated the mat during the low light intensity, short photoperiod winter season. With increasing light intensities and photoperiods the winter ecotypes were replaced by the high light intensity adapted summer ecotypes.
OCCURRENCE OF A EUROPEAN RED ALGA (SCHOTTERA NICAEENSIS) IN SOUTHERN AUSTRALIAN WATERS1
Authors: Lewis John A. , Kraft Gerald T. 
Published: August 2010

ABSTRACTSchottera nicaeensis(Phyllophoraceae, Gigartinales), presently known only from the western Mediterranean Sea and the northeastern Atlantic coasts of Europe, is reported for the first time from the Melbourne region of Port Phillip Bay in southeastern Australia. The species is perennial in the Bay, although tetrasporophytes and cystocarpic plants are commonest in late spring and early summer. This seasonal pattern, and the vegetative habits of plants during the whole of the year, show similarities to populations described by other workers for Northern Hemisphere localities where comparable water temperature and daylength regimes obtain. The small AustralianS. nicaeensiscommunity is found at 5–9 m depths and is concentrated on lighthouse foundations adjacent to the main Port of Melbourne shipping channel. It is hypothesized that the species has recently been introduced into Port Phillip Bay, and a scenario for its possible means of import on ships is suggested.
FACTORS LIMITING EDAPHIC ALGAL BIOMASS AND PRODUCTIVITY IN A GEORGIA SALT MARSH1,2
Authors: Darley W. Marshall , Montague Clay L. , Plumley F. Gerald , Sage William W. , Psalidas Arthur T. 
Published: August 2010

ABSTRACTA “planted core” system was developed to test the effect of short term (1–2 weeks) experimental manipulation of environmental parameters on edaphic microalgae under field conditions. A large number of small cores (surface area = 7 cm2) were collected, randomized and replanted in the marsh in fiddler crab exclosures with appropriate experimental treatments. Daily enrichment of the cores with NH4+ resulted in significant increases in edaphic primary productivity and levels of chlorophyll a in both summer and winter seasons in the short‐Spartina marsh. Enrichment with a complete nutrient solution caused no further increases. Nutrient enrichment of creekbank sediments was much less stimulatory to the resident algal assemblage. In both sites, but especially in the creekbank, the removal of fiddler crab grazers resulted in significant increases in chlorophyll a and productivity. Experimental manipulation of light intensity showed that the average light intensity reaching the sediment surface was saturating for chlorophyll production in the short‐Spartina marsh. A reciprocal transplant experiment involving unfertilized cores from the short‐Spartina marsh and creekbank marsh demonstrated that NH4+ inputs occurring in the creekbank site rapidly alleviated nitrogen limitation of edaphic algae from short‐Spartina marsh. Algae in creekbank cores incubated in the short‐Spartina marsh were unable to sustain high productivity once the original standing stock of NH4+ declined.