bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Myrothecium roridum Causing Leaf Spot on Garden Hydrangea in the United States
Authors: Mmbaga M. T. , Li Y. , Kim M.-S. 
Published: August 2010

Garden hydrangea (Hydrangea macrophylla) is a popular flowering shrub that grows well in Tennessee but foliar diseases impact their appearance, health, and market value. Leaves of garden hydrangea showed necrotic lesions with concentric rings of brown and dark brown at the Tennessee State University Research Center in McMinnville. A fungus was recovered from June and July leaf samples with 20% frequency of isolation from approximately 40 leaf pieces that were surface sterilized and plated in potato dextrose agar (PDA). Isolates developed white colonies and dark gray-to-black, spore-bearing mycelial cushions (sporodochia) that formed on older colonies (30 to 45 days old) at 25 ± 2°C. Conidia were hyaline to slightly dark, one-celled, ovoid to elongate with rounded ends, and 2.0 to 2.5 × 5.5 to 6.5 μm. These morphological characteristics were consistent with those described for Myrothecium roridum Tode ex Fr. (1). DNA sequence for three isolates of this fungus showed identical internal transcribed spacer (ITS) region sequences (GenBank Accession No. HM215150) with 99% maximum sequence identity to M. roridum isolates (GenBank Accession Nos. AJ301994.1 and AJ608978). Another close match (97%) was with M. gramineum (GenBank Accession No. FJ235084) and M. tongaense (GenBank Accession No. AY254157). Pathogenicity of M. roridum was evaluated on detached leaves from three hydrangea cultivars, Nikko Blue, All Summer Beauty, and Blue bird. Four, medium-size, detached leaves were placed in moist chambers and inoculated with 5-mm mycelial plugs from 14-day-old cultures; sterile PDA was used as the control treatment. A randomized, complete-block experimental design was used with a replication of four leaves per cultivar. Incubation temperature was 26 ± 2°C. Necrotic lesions started 4 to 5 days after inoculation in all inoculated leaves; lesions expanded to cover 10 to 25% of the leaf surface and formed concentric rings; sterile PDA plugs did not produce leaf lesions. This experiment was repeated twice and similar symptoms were produced; M. roridum was reisolated from all inoculated leaves. Spray inoculation of detached leaves of hydrangea cv. Pretty Maiden with 5 × 104 spores/ml produced similar symptoms; leaves sprayed with water remained symptom free. M. roridum has a wide host range and similar symptoms have been reported on other ornamentals including salvia (2), begonia ( http://mrec.ifas.ufl.edu/foliage/folnotes/begonias.htm ), gardenia ( http://cfextension.ifas.ufl.edu/agriculture/ nursery_production/ documents/Gardenia.pdf ), and cotton (3). To our knowledge, this is the first report of M. roridum causing leaf spot on H. macrophylla in the United States. References: (1) M. B. Ellis. Page 465 in: More Damatacous Hyphomycetes. CABI, Wallingford, UK. 1993. (2) J. A. Mangandi et al. Plant Dis. 91:772, 2007. (3) R. L. Munjal. Indian Phytopathol. New Delhi, 13:150, 1960.
Acid‐base regulation during ammonium assimilation in Hydrodictyon africanum
Authors: RAVEN J. A. , DE MICHELIS M. I. 
Published: August 2010

Abstract The acid‐base balance during ammonium (used to mean NH 4+ and/or NH3) assimilation in Hydrodictyon africanum has been measured on cells growing with about 1 mol m−3 ammonium at an external pH of about 6.5. Measurements made included (1) ash alkalinity (corrected for intracellular ammonium) which yields net organic negative charge, (2) the accumulation of organic N in the cells and (3) the change in extracellular H+ (from the pH change and the buffer capacity). These measurements showed that some 0.25 excess organic negative charge (half in the cell wall, half inside the plasmalemma) accumulates per organic N synthesized, while some 1.25H+ accumulate in the medium per organic N synthesized. Granted a permeability (PNH3) of some 10−3 cm s−1, and a finite [NH3] in the cytoplasm of these N‐assimilating cells it is likely that most of the ammonium entering these growing cells is as NH 4+. This means that most of the H + appearing in the medium must have originated from inside the cell and have been subjected to active efflux at the plasmalemma: H+ accumulates in the medium equivalent to any NH3 entry by requilibration from exogenous NH 4+. The cell composition (net organic negative charge, organic N content) is very similar in these ammonium‐grown cells to that of NO3+grown cells, suggesting that there is no action of a ‘biochemical pH stat’ during longterm assimilation of NO3+in H. africanum.Short‐term experiments were carried out at an external pH of 7.2 in which ammonium at various concentrations were supplied to NO3+‐grown cells. There was in all cases a rapid influx followed by a slower uptake; at least at the lower concentrations (less than 100 μmol dm−3) the net influx was all attributable to NH4+influx via a uniporter, probably partly short‐circuited by a passive NH3 efflux due to intrinsic membrane permeability to NH3. The net ammonium influx was in all cases associated with H+ accumulation in the medium. (1.3‐1.7 H + per ammonium taken up); as in the growth experiments, most of the ammonium taken up was assimilated.Determinations of cytoplasmic pH showed either no effect on, or a slight decrease in, pH during ammonium assimilation; the changes that occurred were in the direction expected for actuating a ‘pH‐regulating’ change in H+ fluxes.
Incorporating Gene Functional Annotations in Detecting Differential Gene Expression
Authors: Pan Wei 
Published: August 2010

SummaryThe importance of incorporating existing biological knowledge, such as gene functional annotations in gene ontology, in analysing high throughput genomic and proteomic data is being increasingly recognized. In the context of detecting differential gene expression, however, the current practice of using gene annotations is limited primarily to validations. Here we take a direct approach to incorporating gene annotations into mixture models for analysis. First, in contrast with a standard mixture model assuming that each gene of the genome has the same distribution, we study stratified mixture models allowing genes with different annotations to have different distributions, such as prior probabilities. Second, rather than treating parameters in stratified mixture models independently, we propose a hierarchical model to take advantage of the hierarchical structure of most gene annotation systems, such as gene ontology. We consider a simplified implementation for the proof of concept. An application to a mouse microarray data set and a simulation study demonstrate the improvement of the two new approaches over the standard mixture model.
DIVERSITY OF PLASTID DNA CONFIGURATION AMONG CLASSES OF EUKARYOTE ALGAE1
Authors: Coleman Annette W. 
Published: August 2010

ABSTRACTInformation is presented concerning the overall arrangement of plastid DNA (ptDNA) in plastids of approximately 100 spp. of eukaryote algae, representing all classes. The three‐dimensional arrangement of the ptDNA was assessed by study of both living and fixed material, stained with the DNA fluorochrome 4′,6‐diamidino‐2‐phenylindole (DAPI), using both phase and fluorescence microscopy. The widespread occurrence of two major types of ptDNA configuration known from prior electron microscopy studies was confirmed. These are (1) DNA densities (nucleoids) of variable size and morphology, scattered throughout the plastid, and (2) a ring nucleoid, beaded or unbeaded, lying just within the girdle lamella. Type 1 is characteristic of Rhodophyta, Dinophyta, Chlorophyta, Cryptophyta, Prymnesiophyceae and Eustigmatophyceae (with one exception). Type 2 is characteristic of Phaeophyceae, Bacillariophyceae, Raphidophyceae, Chrysophyceae (except silicoflagellates and organisms such asSynuraandDinobryon),and Xanthophyceae (with the exception ofVaucheriaand three genera known to lack girdle lamellae,Bumilleria, Bumilleriopsis,andPseudobumilleriopsis).Some of these exceptional forms, as well as Euglenophyta, have configurations of ptDNA not previously recognized. In all the configurations observed, the DNA of a single plastid could be interpreted as being in continuity.This character of plastids appears to be stable under varied conditions of growth and at differing stages of the life cycle, where examined, and has confirmed the reclassification made on other grounds of several taxonomic entities. It has also revealed new questionable classifications. Since DAPI staining is far simpler than serial sectioning for electron microscopy in revealing ptDNA architecture, use of the technique may be valuable for future studies of numerous organisms, both to help in their identification and as an aid to unravelling major taxonomic affinities. In light of the endosymbiont hypothesis, plastid characters may require as great attention as those of the remainder of the cell.
OSMOTIC ADJUSTMENT INLAMINARIA DIGITATA(PHAEOPHYTA) WITH PARTICULAR REFERENCE TO SEASONAL CHANGES IN INTERNAL SOLUTE CONCENTRATIONS1
Authors: Davison Ian R. , Reed Robert H. 
Published: August 2010

ABSTRACTLaboratory studies have indicated that Na+, K+(together with Cl−the presumed counter‐ion to these cations), NO3−and mannitol represent the major cellular osmotica inLaminaria digitata(Huds.) Lamour. The cellular content of NO3−(together with a fraction of the K+pool which acts as the counter‐ion to NO3−) was found to be inversely proportional to that of mannitol, suggesting thatL. digitatamaintains a constant turgor by means of an isotonic substitution between these compounds. An analysis of the seasonal changes in solute content in an Arbroath (Scotland) population ofL. digitataconfirmed this hypothesis and indicated that the total pool of stored photosynthate was partitioned between the interconvertible carbohydrates mannitol and laminaran (which has a much lower osmotic potential than mannitol) depending on the size of the cellular pool of NO3−.
CHEMICAL PROFILE OF SELECTED SPECIES OF MICROALGAE WITH EMPHASIS ON LIPIDS1
Authors: Ben‐Amotz Ami , Tornabene Thomas G. , Thomas William H. 
Published: August 2010

ABSTRACTThe lipid profile of seven species of unicellular eukaryotic microalgae grown under controlled conditions was studied with emphasis on the hydrocarbons and the fatty acids as part of a search for oil‐producing algae. Green, slow‐growing colonies of Botryococcus braunii Kutz contained the highest lipid content of 45% based on the organic weight, with an increase to 55% under nitrogen deficiency and with no effect of sodium chloride stress. Ankistrodesmus sp. Thomas, Dunaliella spp., Isochrysis sp., Nannochloris sp. Thomas, and Nitzschia sp. Chapman contained an average of 25% lipids under nitrogen sufficient conditions. Nitrogen deficiency resulted in significant increase in the lipid content in all species but Dunaliella spp., which produced a higher content of carbohydrates. Significant low amounts of acyclic hydrocarbons were detected only in Botryococcus braunii Kutz and not in the other algae. The major hydrocarbon fractions in nitrogen deficient Botryococcus braunii Kutz, Dunaliella salina Thomas, Isochrysis spp. and Nannochloris sp. Thomas were cyclic and branched polyunsaturated components which were identified as various isoprenoid derivatives. The polar lipid composition of glycolipids and phospholipids of all species investigated was fairly typical of photosynthetic eukaryotic algae. Fatty acid composition was species specific, with changes occurring in the relative amounts of individual acids of cells cultivated under different conditions and growth phases. All species synthesized C14:0, C16.0, C18:1, C18:2 and C18:3 fatty acids; C 16:4 in Ankistrodesmus sp. Thomas; C18:4 and C 22.6 in Isochrysis sp.; C16:2, C16:3 and C20:5 in Nannochloris sp. Thomas; C16:2, C16:3 and C20:5 in Nitzschia sp. Chapman. Nitrogen deficiency and salt stress induced accumulation of C18:1 in all treated species and to a lesser extent in Botryococcus braunii Kutz. The low production of hydrocarbons under optimal growth conditions and the high production of hydrocarbons under limited growth conditions cannot support the notion that microalgae can be utilized as biosolar energy converters for the production of liquid fuel, but point to the availability of a variety of neutral and polar lipid products.
TWO NEW SPECIES OF TAYLORIELLA (RHODOMELACEAE, RHODOPHYTA) FROM THE NORTHEASTERN NORTH PACIFIC1
Authors: Wynne Michael J. 
Published: August 2010

ABSTRACTTwo new species are recognized in the rhodomelacean genus Tayloriella Kylin: T. divaricata sp. nov. and T. abyssalis sp. nov. These two taxa are distributed in the northeastern North Pacific, the former ranging from Amchitka Island in the Aleutians through southcentral Alaska to northern British Columbia, and the latter ranging also from Amchitka Island through southcentral Alaska and British Columbia into northern Washington. A characteristic of these two species shared with the type of Tayloriella is that the abaxial lateral always overtops the monopodially developed axes in every order of branching. The laterals have little congenital fusion with the parent axes. A common feature in these two species is that the laterals are terminated in a relatively long monosiphonous portion (usually 6 or 7 cells). The relationship of Tayloriella to Pterosiphonia and Pterosiphoniella is discussed.
INTERACTIONS BETWEEN LIGHT, NH4+, AND CO2 IN BUOYANCY REGULATION OF ANABAENA FLOS‐AQUAE (CYANOPHYCEAE)1
Authors: Spencer Craig N. , King Darrell L. 
Published: August 2010

ABSTRACTBuoyancy of the gas‐vacuolate alga Anabaena flosaquae Brébisson was measured under various levels of light, NH4+, and CO2. At high irradiance (50 μE · m−2·−1) the alga was non‐buoyant regardless of the availability of CO2 and NH4+. At low irradiance (≤10 μE · m −2· s−1) buoyancy was controlled by the availability of NH4+ and CO2. When NH4+ was abundant, algal buoyancy was high over a wide range of CO2 concentrations. In the absence of NH4+, algal buoyancy was reduced at high CO2 concentrations, however as the CO2 concentration declined below about 5 μmol · L−1, algal buoyancy increased. These results help explain why gas vacuolate, nitrogen‐fixing blue‐green algae often form surface blooms in eutrophic lakes.
STUDIES IN PENNATE DIATOMS: VALVE MORPHOLOGIES OF LICMOPHORA AND CAMPYLOSTYLUS1
Authors: Wahrer Richard J. , Fryxell Greta A. , Cox Elenor R. 
Published: August 2010

ABSTRACTUsing scanning electron and light, microscopy, several hundred specimens of Campylostylus normanianus (Grev.) Gerloff, Licmophora abbreviata Agardh, L. gracilis var. anglica (Kütz) Per. et Per., and L. flabellata (Carm.) Agardh were examined to elucidate their valve morphology. These species were found to be heterovalvar with respect to the presence of the labiate process in the basal apices of the cell, although one was always present at the head pole of each valve. This form of heterovalvar may be one basis for partitioning the large and variable family Diatomaceae. Because of the similar valve morphologies exhibited by C. normanianus and Licmophora species examined, it is recommended that Campylostylus normanianus be placed in the older genus Licmophora, as L. normaniana (Grev.) Wahrer.
LIGHT, TEMPERATURE AND PHOTOPERIOD AS FACTORS CONTROLLING REPRODUCTION INULOTHRIX ZONATA(ULVOPHYCEAE)1
Authors: Graham James M. , Graham Linda E. , Kranzfelder James A. 
Published: August 2010

ABSTRACTIn many lakes in the northern United States and Canada the filamentous green algaUlothrix zonata(Weber and Mohr) Kütz grows abundantly in early spring in shallow waters. Asexual reproduction occurs by formation of quadriflagellate zoospores which disrupt, the integrity of the cells upon release causing the filament to disintegrate. Study of the effects of 100 different combinations of irradiance, temperature and photoperiod revealed that zoospore formation is favored by high temperatures near 20°C, high light levels of 520 μE·m−2·s−1and photoperiods of either short day (8:16 h light‐dark) or long day cycles (16:8 h light‐dark). Zoospore formation is minimal under conditions of low temperature (5°C), low irradiance (32.5 μE·m−2·s−1) and neutral day‐lengths (12:12 h light‐dark). These observations explain the decline inU. zonatabiomass when water temperatures rise above 10° C. The combined effect of rising water temperatures and increasing daylengths causes progressively more filaments to switch from vegetable growth to zoospore production resulting in an increasing loss of biomass.
MORPHOLOGICAL VARIATION WITHIN AND BETWEEN NATURAL POPULATIONS OF NON‐TIDE POOL FUCUS DISTICHUS (PHAEOPHYTA) IN NEW ENGLAND1,2
Authors: Sideman Eric J. , Mathieson A. C. 
Published: August 2010

ABSTRACTThe sources of morphological variation in natural populations of Fucus distichus L. ssp. edentatus (De la Pyiaie) Powell and F. distichus L. ssp, evanescens (C. Agardh) Powell from New England were evaluated. Individuals from different populations were morphologically distinct as judged by population means and analysis of variance. A correlation between the plant's form and its habitat was established by field observation. The broadest material grows in calm estuarine habitats, while the narrowest plants occur in exposed, open coastal areas. Major differences in morphology also appear seasonally. In addition, microhabitat factors such as exposure to wave action and elevation explain some morphological variation. Cultured germlings from distinct populations of “evanescens” and “edentatus” type plants were outplanted to an experimental garden in order to ascertain whether the variation was heritable or environmentally induced. The latter experiments indicate that major differences in morphology are genetically determined.
DISTRIBUTION, SEASONALITY AND REPRODUCTIVE PHENOLOGY OFBANGIA ATROPURPUREA(RHODOPHYTA) IN RHODE ISLAND, U.S.A.1
Authors: Sheath Robert G. , VanAlstyne Kathryn L. , Cole Kathleen M. 
Published: August 2010

ABSTRACTForty‐seven sites along the Rhode Island coastline were sampled on a seasonal basis for the presence of the red algaBangia atropurpurea(Roth) C. Ag. This species was found to be widely distributed, occurring at 94% of the hard, stable substrates sampled.Bangiapopulations were most, widespread in the winter (71% of sites) and least frequent in the summer (29% of sites). At one location, three high intertidal populations (average height 101 cm) and three low intertidal populations (average height 14 cm) were sampled monthly for two years. The upper intertidal populations appeared in September and persisted until at least May, whereas the lower populations were ephemeral, appearing for only a few months in late winter. The high intertidal populations were present on 85% of the sampling dates white the lower ones were observed on 25% of the sampling dates. Upper intertidal filaments reproduced exclusively by asexual monospores unlike those of the lower populations which were largely sexual. The maximum diameter of asexual and carpogonial filaments was 120 and 250 nm, respectively. Monosporagenesis was strongly correlated to temperature whereas gametogenesis was strongly correlated to photopriod.
TRANSLOCATION OF IODINE IN LAMINARIA SACCHARINA(PHAEOPHYTA)1
Authors: Amat Mireille A. , Srivastava Lalit M. 
Published: August 2010

ABSTRACTLong‐distance translocation of 125I in Laminaria saccharina (L.) Lamour. followed a “source to sink” pattern. When the source of 125I was placed on the distal mature part of the blade, the translocation was unidirectional, basipetal and directed towards the meristematic region at the blade‐stipe junction. When the source was placed directly at the meristem there was no movement of label distal to the meristem. The velocity of125I transport ranged from 2 to 3.5 cm · h−1. The anion I− seemed to be the only species of125I transported. An assay of iodine content in different parts of L. saccharina plant showed much higher levels of iodine in the meristem, stipe and holdfast than in the blade. This distribution concurs well with the pattern of I− translocation.
PHOTOSYNTHESIS‐IRRADIANCE RELATIONSHIPS IN SEA ICE MICROALGAE FROM McMURDO SOUND, ANTARCTICA1
Authors: Palmisano Anna C. , SooHoo Janice Beeler , Sullivan Cornelius W. 
Published: August 2010

ABSTRACTSea ice microalgae in McMurdo Sound, Antarctica were examined for photosynthesis‐irradiance relationships and for the extent and time course of their photoadaptation to a reduction in in situ irradiance. Algae were collected from the bottom centimeter of coarse‐grained congelation ice in an area free of natural snow cover. Photosynthetic rate was determined in short term (1 h) incubations at −2° C over a range of irradiance from 0 to 286 μE·m−2·s−1. Assimilation numbers were consistently below 0.1 mg C·mg chl a−1·h−1. The Ik's3 averaged only 7 μE·m−2·s−1, and photosynthesis was inhibited at irradiances above 25 μE·m−2·s−1.Photosynthetic parameters of the ice algal community were examined over a nine day period following the addition of 4 cm of surface snow while a control area remained snow‐free. A reduction of 40% in PmB relative to the control occurred after two days of snow cover; α, β, Ik, and Im were not significantly altered. Low assimilation numbers and constant standing crop size, however, suggested that the algal bloom may have already reached stationary growth phase, possibly minimizing their photoadaptive response.
GROWTH AND BRANCHED HYDROCARBON PRODUCTION IN A STRAIN OF BOTRYOCOCCUS BRAUNII (CHLOROPHYTA)1
Authors: Wolf Fred R. , Nonomura Arthur M. , Bassham James A. 
Published: August 2010

ABSTRACTA strain Botryococcus braunii Kütz. that produces high levels of branched hydrocarbons (botryococcenes) was grown under different environmental conditions to investigate the relationship between growth and hydrocarbon production. Carbon dioxide concentration had the most significant influence on growth; 0.3% CO2‐enriched cultures demonstrated a minimum mass doubling time of ca. 40 h, compared to ca. 6 days for ambient air cultures grown on the same buffered growth medium. The botryococcene fraction, which consisted of 10 identified compounds (CnH2n‐10; n = 30–34), usually constituted ca. 25–40% of the culture dry weight under various growth regimes, including nitrogen‐ and/or phosphate‐deficiencies. CO2 enrichment initially favored the production of the lower botryococcenes (C30–C32), whereas relatively slow‐growing ambient air cultures accumulated C33 and C34 compounds.Colony color changed in response to different light intensities. High light increased the carotenoid/chlorophyll ratio, which resulted in orange colonies. Cultures exposed to low light intensity appeared green. This change in coloration was reversible over a period of a few days, and at no time were the linear hydrocarbons characteristic of the other form of the alga detected. Ostensible colony color is not, therefore, a reliable indicator of qualitative hydrocarbon content.Sequential solvent extraction experiments indicated that up to ca. 7% of the botryococcene fraction was intracellular and that the remainder was located within the colonial matrix. The internal (cellular) pool principally consisted of C30–C32 botryococcenes, whereas the external (colonial matrix) pool contained >99% of the C33 and C34 compounds, in addition to large amounts of the lower botryococcenes. These results, taken in conjunction with other data, are compatible with the hypothesis that the C30 botryococcene is the precursor, presumably via methylation, of the higher botryococcenes.
UTEX 1336: PERIDINIUM CINCTUM OR PERIDINIUM VOLZII (DINOPHYCEAE)?1
Authors: Pfiester Lois A. , Carty Susan 
Published: August 2010

ABSTRACTPlate pattern variation in UTEX clone 1336 and published photographs using this clone indicate the presence of two taxa: Peridinium cinctum and Peridinium volzii. All subclones established from UTEX 1336 contain the same two cell types. The identification of UTEX 1336 and its future use by researchers are discussed.