bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical transition process in AgOx super‐resolution near‐field structure
Authors: Ho F. H. , Lin W. Y. , Chang H. H. , Wang P. , Tsai D. P. 
Published: October 2010

SummaryA sandwiched 15 nm AgOx thin film of the super‐resolution, near‐field optical disk was studied using a confocal Z‐scan system. Nonlinear optical properties of quartz glass/ZnS–SiO2 (170 nm)/AgOx (15 nm)/ZnS–SiO2 (40 nm) were measured using a Q‐switch Nd : YAG pulse laser of wavelength 532 nm, pulse width 0.7 ns, and 15.79 kHz repetition rate. Transmittance and reflectance of the sandwiched AgOx thin film show important optical responses at the focused position of Z‐scan. The dissociation processes of AgOx, recombination of the silver and oxygen, and the resonance of the localized surface plasmon of the nano‐composites of the AgOx thin film are correlated to transmittance and reflectance at the focused position of the Z‐scan for different input laser powers. An irreversible upper threshold intensity of 4.40 × 106 mW cm−2 at the focused position was found. A reversible working window of the focusing intensity between 1.86 × 106 and 4.40 × 106 mW cm−2 was measured with sandwiched AgOx thin film alone. The near‐field interactions of the AgOx thin film and the recording layers of super‐resolution near‐field optical disk are also discussed.
Near‐field optics and quantum optics: an assignation arranged by four kinds of photons
Authors: Keller O. 
Published: October 2010

SummaryIn the process of emergence a photon emitted from an atom (or a molecule) is usually no better localized in space than to the near‐field zone of the source. Near‐field optics therefore is of central importance for understanding fundamental statistical aspects related to single‐photon tunnelling, the space–time description of photon dynamics, and the photon position‐operator problem. In the present work an attempt is made to study the microscopic near‐field optical interaction from a quantum statistical point of view. In near‐field quantum electrodynamics (QED) scalar and longitudinal photons always are involved and this makes the covariant formulation of QED attractive also in the low‐energy regime. We show that the Lorenz gauge condition on the global state vector relates to the near‐field electrodynamics of the d‐photons. The gauge photon is shown to be of no importance in near‐field interactions. To understand the role of the lack of photon localizability we finally study near‐field quantum optical correlations in a new so‐called propagator gauge.
Development and application of quantum dots for immunocytochemistry of human erythrocytes
Authors: Tokumasu F. , Dvorak J. 
Published: October 2010

SummaryRecent developments in quantum dot technology have resulted in the introduction of new fluorescence immunocytochemical probes. In contrast to organic fluorophores, which are not photostable, the high quantum yield and remarkable photostability of quantum dots solve major problems associated with immunocytochemical studies of erythrocytes. We report here the first application of quantum dots to immunocytochemical studies of human erythrocytes capable of being used in high‐magnification, three‐dimensional erythrocyte reconstruction techniques. The procedure consists of stabilizing human erythrocytes with a homofunctional imidoester cross‐linker to minimize fixative‐induced autofluorescence followed by reacting with a quantum dot – monoclonal antibody complex to label band 3 protein. Our new procedure clearly showed a non‐homogeneous, raft‐like distribution of band 3 protein in the erythrocyte membrane. We also demonstrate the applicability of our technique to studies of erythrocyte membrane modifications occurring during the invasion of a malaria parasite.
Interrater reliability between scorers from eight European sleep laboratories in subjects with different sleep disorders
Authors: Danker‐Hopfe Heidi , Kunz D. , Gruber G. , Klösch G. , Lorenzo J. L. , Himanen S. L. , Kemp B. , Penzel T. , Röschke J. , Dorn H. , Schlögl A. , Trenker E. , Dorffner G. 
Published: October 2010

SummaryInterrater variability of sleep stage scorings is a well‐known phenomenon. The SIESTA project offered the opportunity to analyse interrater reliability (IRR) between experienced scorers from eight European sleep laboratories within a large sample of patients with different (sleep) disorders: depression, general anxiety disorder with and without non‐organic insomnia, Parkinson's disease, period limb movements in sleep and sleep apnoea. The results were based on 196 recordings from 98 patients (73 males: 52.3 ± 12.1 years and 25 females: 49.5 ± 11.9 years) for which two independent expert scorings from two different laboratories were available. Cohen's κ was used to evaluate the IRR on the basis of epochs and intraclass correlation was used to analyse the agreement on quantitative sleep parameters. The overall level of agreement when five different stages were distinguished was κ = 0.6816 (76.8%), which in terms of κ reflects a ‘substantial’ agreement (Landis and Koch, 1977). For different groups of patients κ values varied from 0.6138 (Parkinson's disease) to 0.8176 (generalized anxiety disorder). With regard to (sleep) stages, the IRR was highest for rapid eye movement (REM), followed by Wake, slow‐wave sleep (SWS), non‐rapid eye movement 2 (NREM2) and NREM1. The results of regression analysis showed that age and sex only had a statistically significant effect on κ when the (sleep) stages are considered separately. For NREM2 and SWS a statistically significant decrease of IRR with age has been observed and the IRR for SWS was lower for males than for females. These variations of IRR most probably reflect changes of the sleep electroencephalography (EEG) with age and gender.
Rapid eye movement activity before spontaneous awakening in elderly subjects
Authors: Ficca G. , Scavelli S. , Fagioli I. , Gori S. , Murri L. , Salzarulo P. 
Published: October 2010

SummaryPrevious research in young subjects found that rapid eye movement (REM) density is higher in those REM phases which are followed by an awakening (REM‐W) than in those preceding NREM (REM‐N), suggesting a ‘gating role’ of REM sleep toward the awakening. It is not yet known whether this evidence is maintained in elderly subjects, who display, relative to young subjects, more awakenings, different sleep states from which the awakenings come (NREM in a high proportion of cases) and a general impairment of rapid eye movement activity (REMA). To investigate this issue, we have compared in three different age groups (young, old and ‘old old’ subjects) the features of REMA, including REM density and the amount and duration of REM bursts, between REM‐W and REM‐N. Whereas in the young REM density is higher in REM‐W than in REM‐N, this difference is already reduced in the old group and fully cancelled in the old old subjects. The evidence that old individuals spontaneously wake up despite the absence of an increase of REMA could imply that in the aged awakening is not preceded by an increase of the arousal level (expressed in REM sleep by the REMA). The similar duration of REM bursts for REM‐W and REM‐N in both groups of old subjects suggests that with age a marked impairment occurs in the organizational aspects of REMs, independently from the following state.
Corticospinal excitability and sleep: a motor threshold assessment by transcranial magnetic stimulation after awakenings from REM and NREM sleep
Authors: Bertini Mario , Ferrara Michele , De Gennaro Luigi , Curcio Giuseppe , Fratello Fabiana , Romei Vincenzo , Pauri Flavia , Maria Rossini Paolo 
Published: October 2010

SummaryTranscranial magnetic stimulation (TMS) is a recently established technique in the neurosciences that allows the non‐invasive assessment, among other parameters, of the excitability of motor cortex. Up to now, its application to sleep research has been very scarce and because of technical problems it provided contrasting results. In fact delivering one single suprathreshold magnetic stimulus easily awakes subjects, or lightens their sleep. For this reason, in the present study we assessed motor thresholds (MTs) upon rapid eye movement (REM) and non‐rapid eye movement (NREM) sleep awakenings, both in the first and in the last part of the night. Taking into account that a full re‐establishment of wake regional brain activity patterns upon awakening from sleep needs up to 20–30 min, it is possible to make inferences about the neurophysiological characteristics of the different sleep stages by analyzing the variables of interest immediately after provoked awakenings. Ten female volunteers slept in the lab for four consecutive nights. During the first night the MTs were collected, following a standardized procedure: 5 min before lights off, upon stage 2 awakening (second NREM period), upon REM sleep awakening (second REM period), upon the final morning awakening (always from stage 2). Results showed that MTs increased linearly from presleep wakefulness to REM sleep awakenings, and from the latter to stage 2 awakenings. There was also a time‐of‐night effect on MTs upon awakening from stage 2, indicating that MTs decreased from the first to the second part of the night. The increase in corticospinal excitability across the night, which parallels the fulfillment of sleep need, is consistent with the linear decrease of auditory arousal thresholds during the night. The maximal reduction of corticospinal excitability during early NREM sleep can be related to the hyperpolarization of thalamocortical neurons, and is in line with the decreased metabolic activity of motor cortices during this sleep stage. On the contrary, the increase of MTs upon REM sleep awakenings should reflect peripheral factors. We conclude that our findings legitimate the introduction of the TMS technique as a new proper tool in sleep research.
Oleoyl‐CoA is not an immediate substrate for fatty acid elongation in developing seeds of Brassica napus
Authors: Hlousek‐Radojcic Alenka , Imai Hiroyuki , Jaworski Jan G. 
Published: October 2010

SummaryThe substrate specificity of fatty acid elongase was studied using an oil body fraction from developing seeds of Brassica napus. ATP was essential for high rates of elongase activity, but there was no apparent requirement for oleoyl‐CoA, oleic acid (18:1) or CoA. Furthermore, 14C from 18:1‐CoA was incorporated into eicosenoic (20:1) and erucic (22:1) acids at a much slower rate than 14C from malonyl‐CoA. Incubation of [14C]18:1‐CoA with the oil body fraction resulted in a rapid loss of [14C]18:1‐CoA into several lipid fractions whether in the absence or presence of ATP, but the loss of 18:1‐CoA had a comparatively small effect on the overall rate of elongation. Acyl‐CoAs were derivatized to their respective acylbutylamide and analyzed by gas chromatography‐mass spectrometry. This analysis of acyl‐CoAs demonstrated that there was no detectable 20:1‐CoA or 22:1‐CoA at 0 min incubation, while newly synthesized 20:1‐CoA and 22:1‐CoA were present at 10 min. Analysis of the %14C of the substrates and products of the elongation reaction revealed that the endogenous pool of 18:1‐CoA is quite small in elongase preparations. In addition, [14C]18:1‐CoA added to the incubation, although incorporated into lipids, was not significantly diluted by turnover or new synthesis. In contrast, the %14C of the 20:1‐CoA was two‐ to threefold less than that of the 18:1‐CoA. Taken together, these results indicate that the [14C]18:1 from the [14C]18:1‐CoA was diluted in an intermediate 18:1 pool and that the 18:1‐CoA was not the major donor of the acyl group to the elongase reaction.
A characterization of the MADS‐box gene family in maize
Authors: Mena Montaña , Mandel M. Alejandra , Lerner David R. , Yanofsky Martin F. , Schmidt Robert J. 
Published: October 2010

SummaryStudies on distantly related dicot plant species have identified homeotic genes that specify floral meristem identity and determine the fate of floral organ primordia. Most of these genes belong to a family characterized by the presence of a structural motif, the MADS‐box, which encodes a protein domain with DNA‐binding properties. As part of an effort to understand how such genes may have been recruited during the evolution of flowers with different organ types such as those found in maize, two members of this gene family in maize, ZAG1 and ZAG2, have been characterized previously. Here, the isolation and characterization of four new members of this gene family, designated ZAP1, ZAG3, ZAG4 and ZAG5, are described and the genetic map position of these and 28 additional maize MADS‐box genes is determined. The first new member of this family appears to be the Zea mays ortholog of the floral homeotic gene APETALA1 (AP1) and has been designated ZAP1. One of these genes, ZAG4, is unusual in that its deduced protein sequence includes the MADS domain but lacks the K‐domain characteristically present in this family of genes. In addition, its copy number and expression varies among different inbreds. A large number of maize MADS‐box genes map to duplicated regions of the genome, including one pair characterized here, ZAG3 and ZAG5. These data underscore the complexity of this gene family in maize, and provide the basis for further studies into the regulation of floral organ morphogenesis among the grasses.
A novel lignin in poplar trees with a reduced caffeic acid/5‐hydroxyferulic acid O‐methyltransferase activity
Authors: Van Doorsselaere Jan , Baucher Marie , Chognot Emmanuelle , Chabbert Brigitte , Tollier Marie‐Thérèse , Petit‐Conil Michel , Leplé Jean‐Charles , Pilate Gilles , Cornu Daniel , Monties Bernard , Van Montagu Marc , Inzé Dirk , Boerjan Wout , Jouanin Lise 
Published: October 2010

SummaryLignin is a polymeric constituent of the cell wall that needs to be removed during the paper making process. Bi‐specific caffeic acid/5‐hydroxyferulic acid O‐methyltransferase (COMT) catalyses the O‐methylation of caffeic acid and 5‐hydroxyferulic acid to ferulic acid and sinapic acid, respectively. These compounds are intermediates in the biosynthesis of the lignin precursors. Therefore, COMTs are potential target enzymes for reducing the amount, or modifying the composition, of lignin in plants. Different antisense and sense constructs have been expressed of a gene encoding a COMT from poplar (Populus trichocarpa x P. deltoides) in a P. tremula x P. alba clone under the control of the cauliflower mosaic virus 35S promoter. From all analysed transformants, four lines transformed with an antisense construct had a reduced COMT activity. Two showed a 50% reduction of COMT activity, which altered only slightly the monomeric composition. In the two other transformants, the COMT activity was reduced by 95%. In the latter case, the syringyl/ guaiacyl ratio (S/G) was reduced by sixfold (due to a decrease of S and an increase of G), as analysed by thioacidolysis. A new component of lignin, the 5‐hydroxyguaiacyl residue, was detected among the thioacidolysis products. Moreover, in contrast to the white/yellow colour of wild‐type wood, the xylem of the transgenic lines with a 95% reduction of COMT activity was pale rose. A similar phenotype was observed in brown‐midrib mutants of maize and sorghum, known for their altered lignification. Although the lignin composition was consistently modified, the lignin content of the transgenic poplars was similar to that of the controls.
O‐glycosylation of a precursor to a sweet potato vacuolar protein, sporamin, expressed in tobacco cells
Authors: Matsuoka Ken , Watanabe Natsu , Nakamura Kenzo 
Published: October 2010

SummarySporamin, a vacuolar protein of the sweet potato, is synthesized as a precursor that contains signal peptide and an N‐terminal propeptide that functions as a vacuolar targeting determinant. Sporamin, when expressed in tobacco cells, migrated as smeared bands on an SDS‐polyacrylamide gel. The smearing was due to O‐glycosylation of the precursor to sporamin. The smeared bands were stained by a glycan‐specific stain but no N‐glycosylation site was found in the amino acid sequence of the precursor to sporamin. The glycan attached to sporamin contained galactose and arabinose as major sugar components. Mutations that altered the Pro36 or Ser39 residue of the precursor to sporamin prevented glycosylation of the protein, and analysis by semiquantitative Edman degradation suggested that a glycan moiety was attached to Pro36 and, possibly, to Ser39. Pulse‐labeling and cell‐fractionation experiments revealed that the O‐glycosylation of the precursor to sporamin occurred in the Golgi apparatus. Thus, this modification serves as a good marker of the transport from the endoplasmic reticulum (ER) to the Golgi apparatus of the precursor to sporamin. Treatment of transformed tobacco cells with brefeldin A (BFA) caused the intracellular accumulation of prosporamin that did not migrate as smeared bands. Thus, it appeared that BFA inhibited the transport of the precursor to sporamin to the Golgi apparatus. This result provides the first biochemical evidence that BFA inhibits transport from the ER to the Golgi apparatus in plant cells.
Transposon tagging of the maize Glossy2 locus with the transposable element En/Spm
Authors: Tacke Eckhard , Korfhage Christian , Michel Detlef , Maddaloni Massimo , Motto Mario , Lanzini Simona , Salamini Francesco , Döring Hans‐Peter 
Published: October 2010

SummaryThe Glossy2 (Gl2) locus of maize is required for the formation of the epicuticular wax layer of young plants. gl2 mutant seedlings can be visually identified because of their glossy leaf surface which is different from the dull surface of wild‐type seedlings. The Gl2 locus was isolated by transposon tagging. Seven unstable mutations, gl2‐m2 to gl2‐m8, were induced in a parental strain carrying an active transposable Activator (Ac) element in the unstable wx‐m7 allele. Genetic tests on the gl2‐m2 allele indicated that it was not caused by the Ac element but by the insertion of the transposable element Enhancer/Suppressor‐Mutator (En/Spm). A SaIl restriction fragment segregating with the mutant phenotype was identified, by Southern analysis, using sequences from the En/Spm element as a probe. Part of the fragment was cloned and was shown to carry part of the unstable gl2‐m2 allele. These gl2 sequences were used to identify a genomic fragment carrying the wild‐type allele and to isolate its corresponding cDNA sequence. The predicted Glossy2 protein consists of 426 amino acids. No similar amino acid sequence was found in protein data banks and the biochemical function of the Gl2 gene product is still unknown. The wild‐type Gl2 transcript is found predominantly in juvenile leaves. The transcript level in the leaves of seedlings homozygous for a stable recessive gl2‐ref allele is hardly detectable.
The coat protein of potato virus X is a strain‐specific elicitor of Rx1‐mediated virus resistance in potato
Authors: Bendahmane Abdelhafid , Köhm Bärbel A. , Dedi Cynthia , Baulcombe David C. 
Published: October 2010

SummaryThe Rx1 gene in potato confers extreme resistance to potato virus X (PVX). To investigate the mechanism and elicitation of Rx resistance, protoplasts of potato cv. Cara (Rx1 genotype) and Maris Bard (rx1 genotype) were inoculated with PVX and tobacco mosaic virus (TMV). At 24 h post‐inoculation in Maris Bard protoplasts there was at least 100‐fold more PVX RNA than in protoplasts of Cara. TMV RNA accumulated to the same level in both types of protoplast. However, when the TMV was inoculated together with PVX the accumulation of TMV RNA was suppressed in the Cara (Rx1 genotype) protoplasts to the same extent as PVX. The Rx1 resistance also suppressed accumulation of a recombinant TMV in which the coat protein gene was replaced with the coat protein gene of PVX. It is therefore concluded that Rx1‐mediated resistance is elicited by the PVX coat protein, independently of any other proteins encoded by PVX. The domain of the coat protein with elicitor activity was localized by deletion and mutation analysis to the structural core of a non‐virion form of the coat protein.
Tobacco mitotic cyclins: cloning, characterization, gene expression and functional assay
Authors: Setiady Yulius Yulianto , Sekine Masami , Hariguchi Norimitsu , Yamamoto Takuo , Kouchi Hiroshi , Shinmyo Atsuhiko 
Published: October 2010

SummaryThree cyclin cDNA clones (Ntcyc25, Ntcyc27, Ntcyc29) have been isolated from tobacco (Nicotiana tabacum) using the PCR cloning method. The encoded Ntcyc cyclins were highly homologous to mitotic cyclins. In synchronized tobacco suspension cultured cells, the mRNA levels of Ntcyc25 and Ntcyc27 were detectable through S, G2 and M phases, while the Ntcyc29 mRNA was detected from G2 to M phase. These expression patterns classified the Ntcyc25 and Ntcyc27 into A‐type cyclin and Ntcyc29 into B‐type cyclin. The three genes were expressed in growing tobacco cultured cells but ceased to be expressed when cells entered the stationary phase, indicating that the expression of these cyclin genes was well correlated with cell growth. The N‐terminal truncated Ntcyc25 and Ntcyc29 cDNAs were able to rescue G1 cyclin mutant of Saccharomyces cerevisiae, while the full‐length of Ntcyc27 protein could also partially perform G1 cyclin functions.
Multiple regulatory sites in the C‐terminal autoinhibitory domain of the plasma membrane H+‐ATPase
Authors: Olsson Anne , Johansson Fredrik , Sommarin Marianne , Larsson Christer 
Published: October 2010

SummaryThe H+‐ATPase activities of root and leaf plasma membranes from tobacco (Nicotiana tabacum) have been characterized with respect to Vmax, Km for ATP, pH dependence and activation involving the C‐terminal autoinhibitory domain. With root plasma membranes, addition of lysophosphatidylcholine (lyso‐PC) resulted in the expected increase in Vmax, a decrease in Km(ATP), and a shift in pH optimum to a more alkaline pH, typical for activation via the C‐terminal inhibitory domain. With leaf plasma membranes, however, Km(ATP) was relatively low and the pH optimum was around pH 7.0 before the addition of lyso‐PC and did not change upon addition of the activator, although Vmax increased twofold. Similar results were obtained with the in vivo activator fusicoccin. The results obtained with the leaf plasma membranes show that Vmax may be regulated independently of Km(ATP) and pH optimum, and suggest the presence of at least two regulatory sites within the C‐terminal autoinhibitory domain of the H+‐ATPase.
Isolation of two novel myb‐like genes from Arabidopsis and studies on the DNA‐binding properties of their products
Authors: Li Song Feng , Parish Roger W. 
Published: October 2010

SummaryTwo novel myb‐like genes (atmyb6 and atmyb7) were isolated from an Arabidopsis thaliana cDNA library. The entire proteins or the Myb domains encoded by the genes were expressed as fusion proteins in Escherichia coli. The DNA‐binding domain of the murine c‐Myb was also expressed in the same way for use in comparative studies. The fusion proteins were examined for their DNA‐binding activity using the animal c‐Myb DNA‐binding site (MBS) and the binding site of the maize P gene product (PBS). The Myb domain of Atmyb6 bound to PBS more efficiently than to MBS. Complete Atmyb6 and Atmyb7 proteins preferentially bound to PBS but not MBS. This suggests that the in vitro binding consensus sequences for both Atmyb6 and Atmyb7 are similar to PBS. The binding of the Myb domain of Atmyb6 to both PBS and MBS raises the possibility that the protein recognizes multiple sequences in vivo. The third α‐helix and three adjacent amino acids in the third repeat (R3) of c‐Myb were replaced with the analogous sequence of Atmyb6 to create a chimeric Myb protein. This chimeric protein bound to PBS with a low affinity but failed to bind to MBS. Thus the binding pattern of the chimeric Myb protein is similar to that of the Atmyb6. This result suggests that the last 20 amino acids in the R3 repeat of Atmyb6 play a major role in DNA‐binding.