bluuebunny/crossref_metadata_2025_split huggingface dataset:
The preparation of nano-gold catalyst supported on iron doped titanium oxide
Authors: Dung Dang Thi My , Hanh Nguyen Thi Minh , Phuoc Nguyen Hong 
Published: August 2010

Abstract
We have prepared iron doped TiO
2 samples by the impregnation of TiO
2 (Degussa—P25) with Fe(III) nitrate as an iron precursor. Obtained materials were then characterized by structural x-ray diffraction (XRD) and optical (Uv-vis, Raman) techniques. Later, we deposited very small gold nanoparticles (AuNPs; <5 nm) onto as-prepared supports by a colloidal deposition method, in which lysine was used as a capping agent and a short sonication time was applied to facilitate the dispersion and deposition of AuNPs. The presence of Fe
+3 in the TiO
2 structure was confirmed by an increase in the number of oxygen defect sites that react with O
2 to form reactive oxygen species. Transmission electron microscopy (TEM) was used to determine the size of the gold particles before and after deposition. The AuNPs deposited on the FeTiO2 exhibited good thermal stability against sintering, even at 500 °C for 4 h.
Formation of nanoparticles in aqueous solution from poly(ε-caprolactone)–poly(ethylene glycol)–poly(ε-caprolactone)
Authors: Anh Nguyen Thi Hong , Nguyen Van Cuong 
Published: August 2010

Abstract
The amphiphilic triblock copolymer of poly(ε-caprolactone)-b-poly(ethylene glycol)-b- poly(ε-caprolactone) (PCL–PEG–PCL) was prepared by ring opening polymerization of PEG and ε-caprolactone in the presence of stannous 2-ethyl hexanoate (Sn(Oct)2) as catalyst. The structure of triblock copolymer was characterized by proton nuclear magnetic resonance (1
H NMR), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The polymeric nanoparticles were prepared in aqueous solution by a co-solvent precipitation technique at room temperature. Nanoparticles were formed from the amphiphilic triblock copolymer, and the effect of organic solvent water-miscibility on the size of nanoparticles was also investigated. Polymeric nanoparticles were measured by dynamic light scattering (DLS), with sizes in the range of 70–90 nm and narrow polydispersity. Additionally, the toxicities of polymeric micelles were evaluated by MTT assay. These results confirmed low toxic polymeric micelles and suggest that the polymeric micelles hold a potential for anticancer drug delivery.
Recruitment failure of coastal predatory fish in the Baltic Sea coincident with an offshore ecosystem regime shift
Authors: Ljunggren Lars , Sandström Alfred , Bergström Ulf , Mattila Johanna , Lappalainen Antti , Johansson Gustav , Sundblad Göran , Casini Michele , Kaljuste Olavi , Eriksson Britas Klemens 
Published: July 2010

AbstractLjunggren, L., Sandström, A., Bergström, U., Mattila, J., Lappalainen, A., Johansson, G., Sundblad, G., Casini, M., Kaljuste, O., and Eriksson, B. K. 2010. Recruitment failure of coastal predatory fish in the Baltic Sea coincident with an offshore ecosystem regime shift. – ICES Journal of Marine Science, 67: 1587–1595. The dominant coastal predatory fish in the southwestern Baltic Sea, perch and pike, have decreased markedly in abundance during the past decade. An investigation into their recruitment at 135 coastal sites showed that both species suffered from recruitment failures, mainly in open coastal areas. A detailed study of 15 sites showed that areas with recruitment problems were also notable for mortality of early-stage larvae at the onset of exogenous food-intake. At those sites, zooplankton abundance predicted 83 and 34% of the variation in young of the year perch and pike, respectively, suggesting that the declines were caused by recruitment failure attributable to zooplankton food limitation. Incidences of recruitment failure match in time an offshore trophic cascade that generated massive increases in planktivorous sprat and decreases in zooplankton biomass in the early 1990s. Therefore, sprat biomass explained 53% of the variation in perch recruitment from 1994 to 2007 at an open coastal site, where three-spined stickleback also increased exponentially after 2002. The results indicate that the dramatic change in the offshore ecosystem may have propagated to the coast causing declines of the dominating coastal predators perch and pike followed by an increase in the abundance of small-bodied fish.
NENA, a Lotus japonicus Homolog of Sec13, Is Required for Rhizodermal Infection by Arbuscular Mycorrhiza Fungi and Rhizobia but Dispensable for Cortical Endosymbiotic Development
Authors: Groth Martin , Takeda Naoya , Perry Jillian , Uchida Hisaki , Dräxl Stephan , Brachmann Andreas , Sato Shusei , Tabata Satoshi , Kawaguchi Masayoshi , Wang Trevor L. , Parniske Martin 
Published: July 2010

Abstract
Legumes form symbioses with arbuscular mycorrhiza (AM) fungi and nitrogen fixing root nodule bacteria. Intracellular root infection by either endosymbiont is controlled by the activation of the calcium and calmodulin-dependent kinase (CCaMK), a central regulatory component of the plant's common symbiosis signaling network. We performed a microscopy screen for Lotus japonicus mutants defective in AM development and isolated a mutant, nena, that aborted fungal infection in the rhizodermis. NENA encodes a WD40 repeat protein related to the nucleoporins Sec13 and Seh1. Localization of NENA to the nuclear rim and yeast two-hybrid experiments indicated a role for NENA in a conserved subcomplex of the nuclear pore scaffold. Although nena mutants were able to form pink nodules in symbiosis with Mesorhizobium loti, root hair infection was not observed. Moreover, Nod factor induction of the symbiotic genes NIN, SbtM4, and SbtS, as well as perinuclear calcium spiking, were impaired. Detailed phenotypic analyses of nena mutants revealed a rhizobial infection mode that overcame the lack of rhizodermal responsiveness and carried the hallmarks of crack entry, including a requirement for ethylene. CCaMK-dependent processes were only abolished in the rhizodermis but not in the cortex of nena mutants. These data support the concept of tissue-specific components for the activation of CCaMK.
The Tig1 Histone Deacetylase Complex Regulates Infectious Growth in the Rice Blast Fungus Magnaporthe oryzae
Authors: Ding Sheng-Li , Liu Wende , Iliuk Anton , Ribot Cecile , Vallet Julie , Tao Andy , Wang Yang , Lebrun Marc-Henri , Xu Jin-Rong 
Published: July 2010

Abstract
Magnaporthe oryzae is the most damaging fungal pathogen of rice (Oryza sativa). In this study, we characterized the TIG1 transducin β-like gene required for infectious growth and its interacting genes that are required for plant infection in this model phytopathogenic fungus. Tig1 homologs in yeast and mammalian cells are part of a conserved histone deacetylase (HDAC) transcriptional corepressor complex. The tig1 deletion mutant was nonpathogenic and defective in conidiogenesis. It had an increased sensitivity to oxidative stress and failed to develop invasive hyphae in plant cells. Using affinity purification and coimmunoprecipitation assays, we identified several Tig1-associated proteins, including two HDACs that are homologous to components of the yeast Set3 complex. Functional analyses revealed that TIG1, SET3, SNT1, and HOS2 were core components of the Tig1 complex in M. oryzae. The set3, snt1, and hos2 deletion mutants displayed similar defects as those observed in the tig1 mutant, but deletion of HST1 or HOS4 had no detectable phenotypes. Deletion of any of these core components of the Tig1 complex resulted in a significant reduction in HDAC activities. Our results showed that TIG1, like its putative yeast and mammalian orthologs, is one component of a conserved HDAC complex that is required for infectious growth and conidiogenesis in M. oryzae and highlighted that chromatin modification is an essential regulatory mechanism during plant infection.
Regulation of Cell Proliferation in the Stomatal Lineage by theArabidopsisMYB FOUR LIPS via Direct Targeting of Core Cell Cycle Genes
Authors: Xie Zidian , Lee EunKyoung , Lucas Jessica R. , Morohashi Kengo , Li Dongmei , Murray James A.H. , Sack Fred D. , Grotewold Erich 
Published: July 2010

AbstractStomata, which are epidermal pores surrounded by two guard cells, develop from a specialized stem cell lineage and function in shoot gas exchange. The Arabidopsis thaliana FOUR LIPS (FLP) and MYB88 genes encode closely related and atypical two-MYB-repeat proteins, which when mutated result in excess divisions and abnormal groups of stomata in contact. Consistent with a role in transcription, we show here that FLP and MYB88 are nuclear proteins with DNA binding preferences distinct from other known MYBs. To identify possible FLP/MYB88 transcriptional targets, we used chromatin immunoprecitation (ChIP) followed by hybridization to Arabidopsis whole genome tiling arrays. These ChIP-chip data indicate that FLP/MYB88 target the upstream regions especially of cell cycle genes, including cyclins, cyclin-dependent kinases (CDKs), and components of the prereplication complex. In particular, we show that FLP represses the expression of the mitosis-inducing factor CDKB1;1, which, along with CDKB1;2, is specifically required both for the last division in the stomatal pathway and for cell overproliferation in flp mutants. We propose that FLP and MYB88 together integrate patterning with the control of cell cycle progression and terminal differentiation through multiple and direct cell cycle targets. FLP recognizes a distinct cis-regulatory element that overlaps with that of the cell cycle activator E2F-DP in the CDKB1;1 promoter, suggesting that these MYBs may also modulate E2F-DP pathways.
Environmental Regulation of Lateral Root Emergence inMedicago truncatulaRequires the HD-Zip I Transcription Factor HB1
Authors: Ariel Federico , Diet Anouck , Verdenaud Marion , Gruber Véronique , Frugier Florian , Chan Raquel , Crespi Martin 
Published: July 2010

AbstractThe adaptation of root architecture to environmental constraints is a major agricultural trait, notably in legumes, the third main crop worldwide. This root developmental plasticity depends on the formation of lateral roots (LRs) emerging from primary roots. In the model legume Medicago truncatula, the HD-Zip I transcription factor HB1 is expressed in primary and lateral root meristems and induced by salt stress. Constitutive expression of HB1 in M. truncatula roots alters their architecture, whereas hb1 TILLING mutants showed increased lateral root emergence. Electrophoretic mobility shift assay, promoter mutagenesis, and chromatin immunoprecipitation–PCR assays revealed that HB1 directly recognizes a CAATAATTG cis-element present in the promoter of a LOB-like (for Lateral Organ Boundaries) gene, LBD1, transcriptionally regulated by auxin. Expression of these genes in response to abscisic acid and auxin and their behavior in hb1 mutants revealed an HB1-mediated repression of LBD1 acting during LR emergence. M. truncatula HB1 regulates an adaptive developmental response to minimize the root surface exposed to adverse environmental stresses.
Orchestration of the Floral Transition and Floral Development inArabidopsisby the Bifunctional Transcription Factor APETALA2
Authors: Yant Levi , Mathieu Johannes , Dinh Thanh Theresa , Ott Felix , Lanz Christa , Wollmann Heike , Chen Xuemei , Schmid Markus 
Published: July 2010

AbstractThe Arabidopsis thaliana transcription factor APETALA2 (AP2) has numerous functions, including roles in seed development, stem cell maintenance, and specification of floral organ identity. To understand the relationship between these different roles, we mapped direct targets of AP2 on a genome-wide scale in two tissue types. We find that AP2 binds to thousands of loci in the developing flower, many of which exhibit AP2-dependent transcription. Opposing, logical effects are evident in AP2 binding to two microRNA genes that influence AP2 expression, with AP2 positively regulating miR156 and negatively regulating miR172, forming a complex direct feedback loop, which also included all but one of the AP2-like miR172 target clade members. We compare the genome-wide direct target repertoire of AP2 with that of SCHLAFMÜTZE, a closely related transcription factor that also represses the transition to flowering. We detect clear similarities and important differences in the direct target repertoires that are also tissue specific. Finally, using an inducible expression system, we demonstrate that AP2 has dual molecular roles. It functions as both a transcriptional activator and repressor, directly inducing the expression of the floral repressor AGAMOUS-LIKE15 and directly repressing the transcription of floral activators like SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1.
TRANSLOCATION OF 11C‐PHOTOASSIMILATE IN THE BLADE OF MACROCYSTIS PYRIFERA (PHAEOPHYCEAE)1
Authors: Buggeln R. G. , Fensom D. S. , Emerson C. J. 
Published: August 2010

ABSTRACTRadioactive bicarbonate was pulse fed to blades of Macrocystis pyrifera (L.) C. A. Ag. and the movement of the 11C‐labelled photoassimilates was monitored in vivo using an externally mounted array of Geiger‐Müller detectors. Results of experiments conducted in August 1982 and February 1983 showed kinetic transport profiles composed of short pulses of 11C (periods of two to three minutes and six to eight minutes) and a mass flow component travelling with a speed of 6–22 cm · h−1. The pulse‐like movement of 11C‐photoassimilates, revealed for the first time in a kelp, may be driven by an energy‐assisted transport mechanism. Light microscopy revealed a putative symplastic transport pathway from the photo synthetic meristoderm to the medullary sieve cells in the M. pyrifera blade. Of particular importance were the connections between the inner cortical cells and thin‐walled medullary sieve cells. Electron microscopy showed sieve plate pore diameters ranging between 35–60 nm in the cortex and ca. 40 nm in the end walls of the thin‐walled sieve cells.
AN ASSESSMENT OF ECOLOGICAL CHANGES DURING THE RECENT HISTORY OF LAKE ONTARIO BASED ON SILICEOUS ALGAL MICROFOSSILS PRESERVED IN THE SEDIMENTS1,2
Authors: Stoermer E. F. , Wolin J. A. , Schelske C. L. , Conley D. J. 
Published: August 2010

ABSTRACTQuantitative analysis of siliceous algal microfossils (diatoms and chrysophytes) in a radiometrically dated core of Lake Ontario sediments shows striking modifications of the flora produced and preserved, apparently as a result of anthropogenic modification of nutrient loadings to the lake, Qualitatively similar microfossil assemblages were deposited during the period ca. 1700–1815. A single major event is recorded in assemblages deposited ca. 1769. Between this event horizon and ca. 1815 there was an apparent increase in algal production, but minimal change in species composition. A major disturbance occurred at the level of the Ambrosia horizon, ca. 1831–1847. Assemblages deposited between ca. 1855 and 1900 indicate increasing eutrophication. We infer that silica limitation became important by about 1860 and that the system reached its greatest effective production ca. 1900. Major modification of the flora occurred in the period ca. 1900–1945, with most local extinctions of major indigenous populations occurring ca. 1920–1945. Assemblages deposited in the period ca. 1945–1975 are composed of some stenothermal populations also present in pre‐disturbance assemblages, a large component of benthic and nearshore planktonic species, and a number of apparently planktonic populations rarely recorded from large temperate lakes, particularly species of the genus Nitzschia. Our results indicate that the major factor driving species succession in Lake Ontario was phosphorus enrichment and consequent depletion of available silica supplies. Our results also show the importance of a species' physical niche in determining its survival under these conditions.
KINETICS OF NITROGEN‐15 LABELLED AMMONIUM UPTAKE BY CAULERPA CUPRESSOIDES (CHLOROPHYTA)1,2,3
Authors: Williams Susan Lynn , Fisher Thomas R. 
Published: August 2010

ABSTRACTThe incorporation of 15NH4+ as a function of time and concentration was used to estimate ammonium uptake by Caulerpa cupressoides (West) C. Agardh, taken from its habitat on the sediments of Tague Bay lagoon, St. Croix, U.S. Virgin Islands. 15N‐based uptake rates followed Michaelis‐Menten type saturation kinetics; the maximum uptake rate was 8.7 ± 3.0 μmol N/g dry wt·h at 26° C and the half‐saturation constant was 48 ± 10 μM (X̄± SE). The high half‐saturatiaon constant reflects the dependence of Caulerpa on sediment pore waters as a nitrogen source. Calculations of uptake from isotope time course data were compared to estimates made from ammonium depletion. More ammonium disappeared than could be accounted for by the incorporation of 15N in Caulerpa, and isotope dilution of the ammonium pool is shown not to be responsible for underestimates of uptake, primarily because large 15N additions (40–300 μM) were used. It is suggested that either (1) a secondary ammonium sink such as wall sorption or bacterial uptake significantly influenced ammonium concentrations, or (2) 15N was lost as labelled dissolved organic nitrogen or volatilized during 15N sample preparation.
THE MECHANISM OF DAYLENGTH PERCEPTION IN THE RED ALGA ACROSYMPHYTON PURPURIFERUM1
Authors: Breeman Anneke M. , Hoopen Aart ten 
Published: August 2010

ABSTRACTThe red alga Acrosymphyton purpuriferum (J. Ag.) Sjöst. (Dumontiaceae) is a short day plant in the formation of its tetrasporangia. Tetrasporogenesis was not inhibited by 1 h night‐breaks when given at any time during the long (16 h) dark period (tested at 2 h intervals). However, tetrasporogenesis was inhibited when short (8 h) main photoperiods were extended beyond the critical daylength with supplementary light periods (8 h) at an irradiance below photosynthetic compensation. The threshold irradiance for inhibition of tetrasporogenesis was far lower when supplementary light periods preceded the main photoperiod than when they followed it (<0.05 μmol·m−2·s−1 vs. 3 μmol·m−2·s−1). The threshold level also depended on the irradiance given during the main photoperiod and was higher after a main photoperiod in bright light than after one in dim light (threshold at 3 μmol·m−2·s−1 after a main photoperiod at ca. 65 μmol·m−2·s−1 vs. threshold at <0.5 μmol·m−2·s−1 after a main photoperiod at ca. 35 μmol·m−2·s−1). The spectral dependence of the response was investigated in day‐extensions (supplementary light period (8 h) after main photoperiod (8 h) at 48 μmol·m−2·s−1) with narrow band coloured light. Blue light (λ= 420 nm) was most effective, with 50% inhibition at a quantum‐dose of 2.3 mmol·m−2. However, yellow (λ= 563 nm) and red light (λ= 600 nm; λ= 670 nm) also caused some inhibition, with ca. 30% of the effectiveness of blue light. Only far‐red light (λ= 710 nm; λ= 730 nm) was relatively ineffective with no significant inhibition of tetrasporogenesis at quantum‐doses of up to 20 mmol·m−2.
QUANTITATIVE GENETIC ANALYSIS OF MORPHOLOGICAL VARIATION IN AN ANTARCTIC DIATOM GROWN AT TWO LIGHT INTENSITIES1
Authors: Michelle Wood A. , Lande Russell , Fryxell Greta A. 
Published: August 2010

ABSTRACTTen clonal isolates of Thalassiosira tumida (Janisch) Hasle were grown in duplicate semi‐continuous batch cultures at 116 and 11.6 μE·m−2·s−1 acclimated cells were harvested during exponential growth and cleaned for examination by light microscopy (LM) and scanning electron microscopy (SEM). Number of strutted processes surrounding the central annulus (SP) and average number of satellite pores per process (AVSAT) were counted using SEM on 20 valves from each culture grown in high light, for a total of 400 valves examined; number of marginal labiate processes (LP) and overall diameter (DIAM) were measured using LM on 20 valves from each culture grown in both high and low light for a total of 800 valves examined. Univariate analysis of variance showed that bottle effects resulting from microenvironmental differences between replicates were a small but significant source of variation in DIAM, LP, and SP but not AVSAT. Significant differences among clones were observed for all characters. Decreased irradiance resulted in a significant decrease in valve diameter but no significant effect on LP; no light × clone interaction was observed. Significant covariance between characters among clones was also observed; since valve diameter is known to decrease during asexual growth, the correlation coefficients for SP, AVSAT, and LP with DIAM were used to correct the data for this source of nongenetic differences between clones. Analysis of the size‐corrected data showed that the proportion of total phenotypic variance in SP, LP, and AVSAT caused by genetic differences among clones was 0.14, 0.14, and 0.30, respectively. This indicates that the majority of total phenotypic variance was due to environmental or developmental causes, but that sufficient genetic variability exists to support rapid phenotypic evolution in SP, LP, and AVSAT under continued directional selection. Finally, the results of the genetic analysis revealed a high (0.82) genetic correlation between SP and LP.
STUDIES OF NITRATE TRANSPORT BY MARINE PHYTOPLANKTON USING36Cl‐ClO3−AS A TRANSPORT ANALOGUE. I. PHYSIOLOGICAL FINDINGS1
Authors: Balch William M. 
Published: August 2010

ABSTRACTTransport of a nitrate analogue,36Cl‐ClO3−, was examined in two diatoms,Skeletonema costatum(Greve.) Cleve andNitzschia closterium(Ehrenb) W. Sm. A dinoflagellate,Gonyaulax polyedradid not transport ClO3−. Transport of36Cl‐ClO3−, by diatoms appeared to be active and showed saturation kinetics. The data were fitted by Michaelis‐Menten equation at all but the lowest chlorate concentrations (where plots of S vs. v showed a slight concave bend). Affinity of cells for nitrate was considerably higher than for chlorate. The Kifor nitrate inhibition of chlorate transport was calculated assuming competitive inhibition. Light had little or no effect on chlorate transport. Pulse‐chase experiments demonstrated that (1) ClO3−(hence NO3−) was stored in two intracellular compartments of equal size, (2) internal ClO3−was exchangeable with external ClO3−(rates of efflux and influx were measured), and (3) efflux of intracellular ClO3−showed transient states following a chase of ClO3−or NO3−which stabilized after 10–20 min. Transport of chlorate was a function of growth phase.
PATTERNS OF DISTRIBUTION OF DIATOM ASSEMBLAGES ALONG ENVIRONMENTAL GRADIENTS IN THE SEVERN RIVER ESTUARY, CHESAPEAKE BAY, MARYLAND1
Authors: Wilderman Candice C. 
Published: August 2010

ABSTRACTDistribution patterns of diatoms from natural substrates and surface waters of the Severn River, Maryland, are related to salinity and seasonal gradients through time and spare by minimum spanning tree cluster analysis and principal components analysis. Assemblages were found to be distributed in a complex but orderly fashion, with primary discontinuities occurring between seasons, and between planktonic and attached forms. Within seasons, benthic groupings are distributed as continua along a horizontal salinity gradient, with one discontinuity at a location with a mean salinity of approximately 7‰, Downstream from this discontinuity, most species do not follow the changing salinity patterns from season to season, and are considered euryhaline for a salinity range of 8–16‰. Upstream from this discontinuity there is a relatively distinct and persistent assemblage of oligohaline indicators. Evidence derived by comparing this study with similar studies from Oregon estuaries indicates that similar distribution patterns, community structures and taxa can be expected to occur in estuaries on the east and west coasts of North America.