bluuebunny/crossref_metadata_2025 huggingface dataset:
Thuricin CD, a posttranslationally modified bacteriocin with a narrow spectrum of activity against
Clostridium difficile
Authors: Rea Mary C. , Sit Clarissa S. , Clayton Evelyn , O'Connor Paula M. , Whittal Randy M. , Zheng Jing , Vederas John C. , Ross R. Paul , Hill Colin
Published: May 2010

The last decade has seen numerous outbreaks of
Clostridium difficile
-associated disease (CDAD), which presented significant challenges for healthcare facilities worldwide. We have identified and purified thuricin CD, a two-component antimicrobial that shows activity against
C. difficile
in the nanomolar range. Thuricin CD is produced by
Bacillus thuringiensis
DPC 6431, a bacterial strain isolated from a human fecal sample, and it consists of two distinct peptides, Trn-α and Trn-β, that act synergistically to kill a wide range of clinical
C. difficile
isolates, including ribotypes commonly associated with CDAD (e.g., ribotype 027). However, this bacteriocin thuricin CD has little impact on most other genera, including many gastrointestinal commensals. Complete amino acid sequencing using infusion tandem mass spectrometry indicated that each peptide is posttranslationally modified at its respective 21st, 25th, and 28th residues. Solution NMR studies on [
13
C,
15
N] Trn-α and [
13
C,
15
N]Trn-β were used to characterize these modifications. Analysis of multidimensional NOESY data shows that specific cysteines are linked to the α-carbons of the modified residues, forming three sulfur to α-carbon bridges. Complete sequencing of the thuricin CD gene cluster revealed genes capable of encoding two S′-adenosylmethionine proteins that are characteristically associated with unusual posttranslational modifications. Thuricin CD is a two-component antimicrobial peptide system with sulfur to α-carbon linkages, and it may have potential as a targeted therapy in the treatment of CDAD while also reducing collateral impact on the commensal flora.
Endogenous cannabinoid signaling is essential for stress adaptation
Authors: Hill Matthew N. , McLaughlin Ryan J. , Bingham Brenda , Shrestha Lalita , Lee Tiffany T. Y. , Gray J. Megan , Hillard Cecilia J. , Gorzalka Boris B. , Viau Victor
Published: May 2010

Secretion of glucocorticoid hormones during stress produces an array of physiological changes that are adaptive and beneficial in the short term. In the face of repeated stress exposure, however, habituation of the glucocorticoid response is essential as prolonged glucocorticoid secretion can produce deleterious effects on metabolic, immune, cardiovascular, and neurobiological function. Endocannabinoid signaling responds to and regulates the activity of the hypothalamic–pituitary–adrenal (HPA) axis that governs the secretion of glucocorticoids; however, the role this system plays in adaptation of the neuroendocrine response to repeated stress is not well characterized. Herein, we demonstrate a divergent regulation of the two endocannabinoid ligands,
N
-arachidonylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG), following repeated stress such that AEA content is persistently decreased throughout the corticolimbic stress circuit, whereas 2-AG is exclusively elevated within the amygdala in a stress-dependent manner. Pharmacological studies demonstrate that this divergent regulation of AEA and 2-AG contribute to distinct forms of HPA axis habituation. Inhibition of AEA hydrolysis prevented the development of basal hypersecretion of corticosterone following repeated stress. In contrast, systemic or intra-amygdalar administration of a CB
1
receptor antagonist before the final stress exposure prevented the repeated stress-induced decline in corticosterone responses. The present findings demonstrate an important role for endocannabinoid signaling in the process of stress HPA habituation, and suggest that AEA and 2-AG modulate different components of the adrenocortical response to repeated stressor exposure.
Directionality of nucleocytoplasmic transport of the retroviral gag protein depends on sequential binding of karyopherins and viral RNA
Authors: Gudleski Nicole , Flanagan John M. , Ryan Eileen P. , Bewley Maria C. , Parent Leslie J.
Published: May 2010

Retroviral Gag polyproteins coopt host factors to traffic from cytosolic ribosomes to the plasma membrane, where virions are released. Before membrane transport, the multidomain Gag protein of Rous sarcoma virus (RSV) undergoes importin-mediated nuclear import and CRM1-dependent nuclear export, an intrinsic step in the assembly pathway. Transient nuclear trafficking of Gag is required for efficient viral RNA (vRNA) encapsidation, suggesting that Gag:vRNA binding might occur in the nucleus. Here, we show that Gag is imported into the nucleus through direct interactions of the Gag NC domain with importin-α (imp-α) and the MA domain with importin-11 (imp-11). The vRNA packaging signal, known as ψ, inhibited imp-α binding to Gag, indicating that the NC domain does not bind to imp-α and vRNA simultaneously. Unexpectedly, vRNA binding also prevented the association of imp-11 with both the MA domain alone and with Gag, suggesting that the MA domain may bind to the vRNA genome. In contrast, direct binding of Gag to the nuclear export factor CRM1, via the CRM1-RanGTP heterodimer, was stimulated by ψRNA. These findings suggest a model whereby the genomic vRNA serves as a switch to regulate the ordered association of host import/export factors that mediate Gag nucleocytoplasmic trafficking for virion assembly. The Gag:vRNA interaction appears to serve multiple critical roles in assembly: specific selection of the vRNA genome for packaging, stimulating the formation of Gag dimers, and triggering export of viral ribonucleoprotein complexes from the nucleus.
Small body size and extreme cortical bone remodeling indicate phyletic dwarfism inMagyarosaurus dacus(Sauropoda: Titanosauria)
Authors: Stein Koen , Csiki Zoltan , Rogers Kristina Curry , Weishampel David B. , Redelstorff Ragna , Carballido Jose L. , Sander P. Martin
Published: May 2010

Sauropods were the largest terrestrial tetrapods (>105kg) in Earth's history and grew at rates that rival those of extant mammals.Magyarosaurus dacus, a titanosaurian sauropod from the Upper Cretaceous (Maastrichtian) of Romania, is known exclusively from small individuals (<103kg) and conflicts with the idea that all sauropods were massive. The diminutiveM. dacuswas a classical example of island dwarfism (phyletic nanism) in dinosaurs, but a recent study suggested that the small Romanian titanosaurs actually represent juveniles of a larger-bodied taxon. Here we present strong histological evidence thatM. dacuswas indeed a dwarf (phyletic nanoid). Bone histological analysis of an ontogenetic series ofMagyarosauruslimb bones indicates that even the smallestMagyarosaurusspecimens exhibit a bone microstructure identical to fully mature or old individuals of other sauropod taxa. Comparison of histologies with large-bodied sauropods suggests thatMagyarosaurushad an extremely reduced growth rate, but had retained high basal metabolic rates typical for sauropods. The uniquely decreased growth rate and diminutive body size inMagyarosauruswere adaptations to life on a Cretaceous island and show that sauropod dinosaurs were not exempt from general ecological principles limiting body size.
Type III restriction enzymes cleave DNA by long-range interaction between sites in both head-to-head and tail-to-tail inverted repeat
Authors: van Aelst Kara , Tóth Júlia , Ramanathan Subramanian P. , Schwarz Friedrich W. , Seidel Ralf , Szczelkun Mark D.
Published: May 2010

Cleavage of viral DNA by the bacterial Type III Restriction-Modification enzymes requires the ATP-dependent long-range communication between a distant pair of DNA recognition sequences. The classical view is that Type III endonuclease activity is only activated by a pair of asymmetric sites in a specific head-to-head inverted repeat. Based on this assumption and due to the presence of helicase domains in Type III enzymes, various motor-driven DNA translocation models for communication have been suggested. Using both single-molecule and ensemble assays we demonstrate that Type III enzymes can also cleave DNA with sites in tail-to-tail repeat with high efficiency. The ability to distinguish both inverted repeat substrates from direct repeat substrates in a manner independent of DNA topology or accessory proteins can only be reconciled with an alternative sliding mode of communication.
Infants consider both the sample and the sampling process in inductive generalization
Authors: Gweon Hyowon , Tenenbaum Joshua B. , Schulz Laura E.
Published: May 2010

The ability to make inductive inferences from sparse data is a critical aspect of human learning. However, the properties observed in a sample of evidence depend not only on the true extension of those properties but also on the process by which evidence is sampled. Because neither the property extension nor the sampling process is directly observable, the learner's ability to make accurate generalizations depends on what is known or can be inferred about both variables. In particular, different inferences are licensed if samples are drawn randomly from the whole population (weak sampling) than if they are drawn only from the property's extension (strong sampling). Given a few positive examples of a concept, only strong sampling supports flexible inferences about how far to generalize as a function of the size and composition of the sample. Here we present a Bayesian model of the joint dependence between observed evidence, the sampling process, and the property extension and test the model behaviorally with human infants (mean age: 15 months). Across five experiments, we show that in the absence of behavioral cues to the sampling process, infants make inferences consistent with the use of strong sampling; given explicit cues to weak or strong sampling, they constrain their inferences accordingly. Finally, consistent with quantitative predictions of the model, we provide suggestive evidence that infants’ inferences are graded with respect to the strength of the evidence they observe.
Tone-Affect Compatibility with Affective Stimuli and Affective Responses
Authors: Horstmann Gernot
Published: May 2010

Three experiments examine multimodal integration of tone pitch (high/low), facial expression stimuli (happy/angry), and responses (happy/angry) in a compatibility paradigm. When the participants’ task is to imitate facial expressions (Experiment 1), smiles are facilitated by high tones whereas frowns are facilitated by low tones. Experiments 2 and 3 further analyse this effect and show that there is both integration between the tone stimulus and the facial stimulus and between the tone stimulus and the facial response. Results suggest that pitch height is associated with emotion. An interpretation in terms of an embodied cognition approach that emphasizes an interweavement of perception and action is discussed.
Holistic Representation of Negative Numbers is Formed When Needed for the Task
Authors: Ganor-Stern Dana , Pinhas Michal , Kallai Arava , Tzelgov Joseph
Published: May 2010

Past research suggested that negative numbers are represented in terms of their components—the polarity marker and the number (e.g., Fischer & Rottmann, 2005; Ganor-Stern & Tzelgov, 2008). The present study shows that a holistic representation is formed when needed for the task requirement. Specifically, performing the numerical comparison task on positive and negative numbers presented sequentially required participants to hold both the polarity and the number magnitude in memory. Such a condition resulted in a holistic representation of negative numbers, as indicated by the distance and semantic congruity effects. This holistic representation was added to the initial components representation, thus producing a hybrid holistic-components representation.
Low Income and Poor Health Choices: The Example of Smoking
Authors: Binkley James
Published: May 2010

Low‐income individuals often make relatively unhealthy consumption choices. In the case of food, this is often attributed to limited budgets. We investigate another possibility, motivated by the fact that smoking is more prevalent among those with low incomes, despite the cost. We develop a model in which income serves both as a budget constraint and as a source of future utility. We test the model by estimating logistic models of beginning and quitting smoking. We find support for the idea that low‐income consumers make less healthy choices because they face lower costs in terms of forgone future utility.
Lactobacillus koreensis sp. nov., isolated from the traditional Korean food kimchi
Authors: Bui Thi Phuong Nam , Kim Yeon-Ju , In Jun-Gyo , Yang Deok-Chun
Published: May 2010

A lactic acid bacterium, strain DCY50T, isolated from the traditional Korean food kimchi, was studied to determine its taxonomic position. The strain was Gram-stain-positive, catalase-negative, facultatively anaerobic, rod-shaped and motile. The genomic DNA G+C content was 49 mol% and the peptidoglycan structure was of the A4α (l–Lys–d-Asp) type. Chemotaxonomic markers of the strain were consistent with its classification in the genus Lactobacillus. Comparisons of 16S rRNA and rpoA gene sequences showed that strain DCY50T was most closely related to the type strains of Lactobacillus parabrevis (98.4 and 91.6 % similarity, respectively, for the 16S rRNA and rpoA genes), L. hammesii (98.0 and 91.2 %), L. brevis (97.6 and 93.3 %) and L. senmaizukei (97.4 and 90.5 %). DNA–DNA relatedness of strain DCY50T to these type strains was below 36 %. According to the genotypic and phenotypic data, strain DCY50T could be differentiated from all known Lactobacillus species and should be classified in a novel species, for which the name Lactobacillus koreensis sp. nov. is proposed; the type strain is DCY50T ( = KCTC 13530T  = JCM 16448T).
Paenibacillus sophorae sp. nov., a nitrogen-fixing species isolated from the rhizosphere of Sophora japonica
Authors: Jin Hao-Jie , Lv Jing , Chen San-Feng
Published: May 2010

A nitrogen-fixing bacterium, designated strain S27T, was isolated from rhizosphere soil of Sophora japonica. Phylogenetic analysis based on a fragment of the nifH gene and the full-length 16S rRNA gene sequence revealed that strain S27T is a member of the genus Paenibacillus. High levels of 16S rRNA gene sequence similarity were found between strain S27T and Paenibacillus durus DSM 1735T (97.3 %), Paenibacillus sabinae DSM 17841T (96.9 %), Paenibacillus forsythiae DSM 17842T (96.7 %) and Paenibacillus zanthoxyli DSM 18202T (96.6 %). However, DNA–DNA hybridization values between strain S27T and the four type strains were 37.64 %, 23.12 %, 25.6 % and 34.99 %, respectively. Levels of 16S rRNA gene sequence similarity between strain S27T and the type strains of other recognized members of the genus Paenibacillus were below 96.5 %. The DNA G+C content of strain S27T was 46.0 mol%. The major fatty acids were anteiso-C15 : 0, C16 : 0 and iso-C16 : 0. The major isoprenoid quinone was MK-7. On the basis of its phenotypic characteristics and DNA–DNA hybridization results, strain S27T is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus sophorae sp. nov. is proposed. The type strain is S27T ( = CGMCC 1.10238T  = DSM 23020T).
Spencermartinsiella europaea gen. nov., sp. nov., a new member of the family Trichomonascaceae
Authors: Péter Gábor , Dlauchy Dénes , Tornai-Lehoczki Judit , Suzuki Motofumi , Kurtzman Cletus P.
Published: May 2010

Ten strains of a novel heterothallic yeast species were isolated from rotten wood collected at different locations in Hungary. Analysis of gene sequences for the D1/D2 domain of the large subunit rRNA, as well as analysis of concatenated gene sequences for the nearly complete nuclear large subunit rRNA, nuclear small subunit rRNA and translation elongation factor 1-α, placed the novel species in the family Trichomonascaceae, but showed that it was distinct from all currently recognized genera. The name Spencermartinsiella europaea gen. nov., sp. nov. is proposed to accommodate the new genus and novel species. The novel species could be distinguished from recognized species of neighbouring genera on the basis of standard phenotypic characteristics. The type and isotype strains of Spencermartinsiella europaea are NCAIM Y.01817T ( = NRRL Y-48265T =  CBS 11730T) and NCAIM Y.01819I ( = NRRL Y-48266I = CBS 11731I), respectively.
Herbidospora sakaeratensis sp. nov., isolated from soil, and reclassification of Streptosporangium claviforme as a later synonym of Herbidospora cretacea
Authors: Boondaeng Antika , Suriyachadkun Chanwit , Ishida Yuumi , Tamura Tomohiko , Tokuyama Shinji , Kitpreechavanich Vichien
Published: May 2010

An actinomycete strain, DMKUA 205T, was isolated from a soil sample collected from the Sakaerat Biosphere Reserve in Nakhonratchasima Province, Thailand. The novel strain produced short chains of non-motile spores on the tips of long sporophores branching from the vegetative hyphae. The morphological and chemotaxonomic properties of this new isolate corresponded to those of members of the genus Herbidospora. Furthermore, 16S rRNA gene sequence analysis showed that the strain was closely related to members of the genus Herbidospora. Phenotypic properties and DNA–DNA relatedness values differentiated the new strain from its closest phylogenetic relatives Herbidospora yilanensis 0351M-12T (35–54 % DNA–DNA relatedness) and Herbidospora daliensis 0385M-1T (58–65 % relatedness). On the basis of phenotypic, genotypic and phylogenetic data, strain DMKUA 205T could be clearly distinguished from the type strains of H. yilanensis and H. daliensis. Therefore, strain DMKUA 205T represents a novel species, for which the name Herbidospora sakaeratensis sp. nov. is proposed. The type strain is strain DMKUA 205T ( = BCC 11662T = NBRC 102641T). In addition, the DNA–DNA hybridization results from this study revealed that Streptosporangium claviforme is a later synonym of Herbidospora cretacea.
Proposal of Heliobacteriaceae fam. nov.
Authors: Madigan Michael T. , Euzéby Jean P. , Asao Marie
Published: May 2010

The family name Heliobacteriaceae is not validly published. The purpose of this note is to provide a description of this family in accordance with the Rules of the Bacteriological Code (1990 Revision).
The Genetics, Transcriptional Profiles, and Catalytic Properties of UDP-α-d-Xylose 4-Epimerases from Barley
Authors: Zhang Qisen , Shirley Neil J. , Burton Rachel A. , Lahnstein Jelle , Hrmova Maria , Fincher Geoffrey B.
Published: May 2010

Cell walls in the grasses contain relatively high levels of heteroxylans and, in particular, arabinoxylans. Enzymes and corresponding genes that are involved in the provision of sugar nucleotide substrates represent potential control points for arabinoxylan biosynthesis. Following expressed sequence tag database analyses, three genes encoding barley (Hordeum vulgare) UDP-d-xylose 4-epimerases (UXE; EC 5.1.3.5), designated HvUXE1, HvUXE2, and HvUXE3, were cloned and their positions on genetic maps defined. To confirm the identity of the genes, a cDNA construct encoding HvUXE1 was expressed in Pichia  pastoris. The purified, recombinant HvUXE1 catalyzed the freely reversible interconversion of UDP-α-d-xylopyranose and UDP-β  -l-arabinopyranose, with K  m values of 1.8 and 1.4 mm, respectively. At equilibrium, the ratio of substrate to product was approximately 1:1. Each molecule of heterologously expressed HvUXE1 enzyme contained about one molecule of noncovalently bound NAD+. Molecular modeling provided a structural rationale for the substrate specificity of the UDP-d-xylose 4-epimerase and, in particular, explained its tight specificity for UDP-xylose compared with other sugar nucleotide epimerases. Quantitative transcript analyses performed for each of the three genes in a range of organs showed, inter alia, that in developing barley endosperm HvUXE1 and HvUXE3 mRNA levels peaked at a time when UDP-α-d-xylopyranose synthase (UXS) transcripts also reached a maximum and when arabinoxylan biosynthesis was initiated. Furthermore, the data revealed that the transcription of HvUXE and HvUXS gene family members is coordinated with the incorporation of pentose sugars onto cell walls in barley leaves, roots, and developing endosperm.
Cucumber Mosaic VirusMovement Protein Severs Actin Filaments to Increase the Plasmodesmal Size Exclusion Limit in Tobacco
Authors: Su Shengzhong , Liu Zhaohui , Chen Cheng , Zhang Yan , Wang Xu , Zhu Lei , Miao Long , Wang Xue-Chen , Yuan Ming
Published: May 2010

Plant viral movement proteins (MPs) enable viruses to pass through cell walls by increasing the size exclusion limit (SEL) of plasmodesmata (PD). Here, we report that the ability of Cucumber mosaic virus (CMV) MP to increase the SEL of the PD could be inhibited by treatment with the actin filament (F-actin)–stabilizing agent phalloidin but not by treatment with the F-actin–destabilizing agent latrunculin A. In vitro studies showed that CMV MP bound globular and F-actin, inhibited actin polymerization, severed F-actin, and participated in plus end capping of F-actin. Analyses of two CMV MP mutants, one with and one without F-actin severing activities, demonstrated that the F-actin severing ability was required to increase the PD SEL. Furthermore, the Tobacco mosaic virus MP also exhibited F-actin severing activity, and its ability to increase the PD SEL was inhibited by treatment with phalloidin. Our data provide evidence to support the hypothesis that F-actin severing is required for MP-induced increase in the SEL of PD. This may have broad implications in the study of the mechanisms of actin dynamics that regulate cell-to-cell transport of viral and endogenous proteins.
Jasmonate and Phytochrome A Signaling inArabidopsisWound and Shade Responses Are Integrated through JAZ1 Stability
Authors: Robson Frances , Okamoto Haruko , Patrick Elaine , Harris Sue-Ré , Wasternack Claus , Brearley Charles , Turner John G.
Published: May 2010

Jasmonate (JA) activates plant defense, promotes pollen maturation, and suppresses plant growth. An emerging theme in JA biology is its involvement in light responses; here, we examine the interdependence of the JA- and light-signaling pathways in Arabidopsis thaliana. We demonstrate that mutants deficient in JA biosynthesis and signaling are deficient in a subset of high irradiance responses in far-red (FR) light. These mutants display exaggerated shade responses to low, but not high, R/FR ratio light, suggesting a role for JA in phytochrome A (phyA) signaling. Additionally, we demonstrate that the FR light–induced expression of transcription factor genes is dependent on CORONATINE INSENSITIVE1 (COI1), a central component of JA signaling, and is suppressed by JA. phyA mutants had reduced JA-regulated growth inhibition and VSP expression and increased content of cis-(+)-12-oxophytodienoic acid, an intermediate in JA biosynthesis. Significantly, COI1-mediated degradation of JASMONATE ZIM DOMAIN1-β-glucuronidase (JAZ1-GUS) in response to mechanical wounding and JA treatment required phyA, and ectopic expression of JAZ1-GUS resulted in exaggerated shade responses. Together, these results indicate that JA and phyA signaling are integrated through degradation of the JAZ1 protein, and both are required for plant responses to light and stress.
TCP1 Modulates Brassinosteroid Biosynthesis by Regulating the Expression of the Key Biosynthetic GeneDWARF4inArabidopsis thaliana
Authors: Guo Zhongxin , Fujioka Shozo , Blancaflor Elison B. , Miao Sen , Gou Xiaoping , Li Jia
Published: May 2010

Brassinosteroids (BRs) are essential phytohormones regulating normal plant growth and development. TCP1, a gene thought to be involved in floral organ symmetric control, was identified as a genetic suppressor of a weak BR receptor mutant, bri1-5, in an activation-tagging genetic screen. TCP1 encodes a putative transcription factor possessing a basic helix-loop-helix domain. The dominant allele of TCP1, tcp1-1D, suppresses the defective phenotypes of bri1-5. Overexpression of a dominant-negative form of TCP1, TCP1-SRDX, with a 12–amino acid repressor sequence fused to TCP1 at its C terminus, results in dwarfed plants resembling BR-deficient or insensitive mutants. The defective phenotypes can be rescued by exogenously applied brassinolide but cannot be recovered by auxins, gibberellins, or cytokinins. BR profile assay (quantitative analysis of BR biosynthetic intermediates) strongly suggests that TCP1 expression level positively coordinates with the function of DWARF4 (DWF4), a key enzyme in BR biosynthesis. Real-time RT-PCR analysis further demonstrated that TCP1 regulates the transcription levels of DWF4, and chromatin immunoprecipitation experiments showed that TCP1 indeed interacts with the DWF4 promoter. Confocal microscopy indicated that TCP1 is mainly confined to the nucleus. The expression of TCP1 appears to be regulated by BR levels. These studies demonstrate another level of regulation through which BRs mediate plant growth and development.
Translocation ofMagnaporthe oryzaeEffectors into Rice Cells and Their Subsequent Cell-to-Cell Movement
Authors: Khang Chang Hyun , Berruyer Romain , Giraldo Martha C. , Kankanala Prasanna , Park Sook-Young , Czymmek Kirk , Kang Seogchan , Valent Barbara
Published: May 2010

Knowledge remains limited about how fungal pathogens that colonize living plant cells translocate effector proteins inside host cells to regulate cellular processes and neutralize defense responses. To cause the globally important rice blast disease, specialized invasive hyphae (IH) invade successive living rice (Oryza sativa) cells while enclosed in host-derived extrainvasive hyphal membrane. Using live-cell imaging, we identified a highly localized structure, the biotrophic interfacial complex (BIC), which accumulates fluorescently labeled effectors secreted by IH. In each newly entered rice cell, effectors were first secreted into BICs at the tips of the initially filamentous hyphae in the cell. These tip BICs were left behind beside the first-differentiated bulbous IH cells as the fungus continued to colonize the host cell. Fluorescence recovery after photobleaching experiments showed that the effector protein PWL2 (for prevents pathogenicity toward weeping lovegrass [Eragrostis curvula]) continued to accumulate in BICs after IH were growing elsewhere. PWL2 and BAS1 (for biotrophy-associated secreted protein 1), BIC-localized secreted proteins, were translocated into the rice cytoplasm. By contrast, BAS4, which uniformly outlines the IH, was not translocated into the host cytoplasm. Fluorescent PWL2 and BAS1 proteins that reached the rice cytoplasm moved into uninvaded neighbors, presumably preparing host cells before invasion. We report robust assays for elucidating the molecular mechanisms that underpin effector secretion into BICs, translocation to the rice cytoplasm, and cell-to-cell movement in rice.
Endocytic and Secretory Traffic in Arabidopsis Merge in the Trans-Golgi Network/Early Endosome, an Independent and Highly Dynamic Organelle
Authors: Viotti Corrado , Bubeck Julia , Stierhof York-Dieter , Krebs Melanie , Langhans Markus , van den Berg Willy , van Dongen Walter , Richter Sandra , Geldner Niko , Takano Junpei , Jürgens Gerd , de Vries Sacco C. , Robinson David G. , Schumacher Karin
Published: May 2010

Plants constantly adjust their repertoire of plasma membrane proteins that mediates transduction of environmental and developmental signals as well as transport of ions, nutrients, and hormones. The importance of regulated secretory and endocytic trafficking is becoming increasingly clear; however, our knowledge of the compartments and molecular machinery involved is still fragmentary. We used immunogold electron microscopy and confocal laser scanning microscopy to trace the route of cargo molecules, including the BRASSINOSTEROID INSENSITIVE1 receptor and the REQUIRES HIGH BORON1 boron exporter, throughout the plant endomembrane system. Our results provide evidence that both endocytic and secretory cargo pass through the trans-Golgi network/early endosome (TGN/EE) and demonstrate that cargo in late endosomes/multivesicular bodies is destined for vacuolar degradation. Moreover, using spinning disc microscopy, we show that TGN/EEs move independently and are only transiently associated with an individual Golgi stack.
Experimental study of water hydraulics application in aviation
Authors: Chua Patrick S.K. , Tan F.L.
Published: May 2010

Purpose

The purpose of this paper is to report an experimental study on the effects of various parameters, such as varying flow velocities of water in the pipe, insulating the water pipe, and heating the pipe, to prevent pressurized water in a water hydraulic system from freezing under sub‐zero ambient temperature environment.

Design/methodology/approach

An experimental test rig was designed, fabricated, and set up to conduct several experiments to investigate the time taken for water to freeze under sub‐zero ambient temperature at −20°C and with the water initially at a higher temperature than the ambient.

Findings

The experiments show that it would take about 90 min for water in the pipe to freeze completely when there is no flow, or water is flowing at slow speed, in the pipe. The results also show that the use of insulation on the pipe would delay the freezing of water inside the pipe; and if used together with heating at several locations on the pipe, freezing of water inside the pipe could be prevented completely.

Originality/value

This paper usefully shows that insulation and heating in a water hydraulic system can prevent freezing of water in the pipe. The promising results of the experimental work mean that water might be able to replace oil in hydraulic systems on aircraft and other low‐temperature applications.
Boundary layer effects on a wing in ground‐effect
Authors: Marshall D.W. , Newman S.J. , Williams C.B.
Published: May 2010

Purpose

The purpose of this paper is to investigate the effect a variety of different boundary layers have on a wing in ground‐effect.

Design/methodology/approach

Experiments were carried out in the University of Southampton's 3′×2′ wind tunnel. A variable length splitter plate was designed and manufactured in order to generate four boundary‐layer thicknesses at a selected measurement position. A single element inverted GA(W)‐1 aerofoil was then introduced to the flow at varying heights above the plate. Laser Doppler anemometry (LDA) and surface static pressure measurements (both on the aerofoil surface and on the splitter plate) were recorded.

Findings

The flow beneath the wing is found to be affected considerably by the presence of the boundary layer. As the boundary‐layer thickness is increased, the under‐wing pressure is observed to increase, hence resulting in decreased suction. Further, the LDA results indicate a modification to the wake profile. In particular, at low wing heights, the wake is observed to become entrained in the boundary layer, to differing degrees dependant on the boundary layer present and the wing height.

Research limitations/implications

The acquisition of force values from the tests will have allowed further understanding of the “real world” implications of the presence of the boundary‐layer thicknesses on a wing in ground‐effect but this is not possible in the test facility used.

Practical implications

The aerodynamics of a wing in ground‐effect are of great interest for both lifting surfaces for aircraft and downforce generation in motorsport applications. The implications of this paper enhance the importance of understanding the boundary conditions present when wind tunnel testing for these applications.

Originality/value

Although the influence of the boundary layer on low ground clearance objects has been well documented, the methods used here, in particular the use of the pressure tapped splitter plate and LDA, allow a further insight into the explanations behind this influence.
Fast trajectory planning based on in‐flight waypoints for unmanned aerial vehicles
Authors: Babaei A.R. , Mortazavi M.
Published: May 2010

Purpose

The purpose of this paper is to propose an efficient algorithm for trajectory planning of unmanned aerial vehicles (UAVs) in 2D spaces. This paper has been motivated by the challenge to develop a fast trajectory planning algorithm for autonomous UAVs through mid‐course waypoints (WPs). It is assumed that there is no prior knowledge of these WPs, and their configuration is computed as in‐flight procedure.

Design/methodology/approach

Since the off‐line techniques cannot be applied, it is required to apply an online trajectory planning algorithm. For this reason, based on the optimal control and the geometry, each segment of trajectory is designed with respect to a local frame. The algorithm is implemented as a real‐time manner in terms of the down‐range variable.

Findings

The proposed algorithm tries to find not only a feasible trajectory (the constraint includes the maximum heading angle rate) but also an optimal trajectory (the objective locally is to minimize the length of the path). This online trajectory planning algorithm gradually produces a smooth 2D trajectory aiming at reaching the mid‐course WPs and the final target so that they are smoothly connected with each other. The mid‐course WPs are described through the given down‐range, cross‐range, and heading angle.

Originality/value

Based on geometrical principles, this algorithm is capable of re‐planning the trajectory as in‐flight manner, and the computational burden approaches the online capabilities for UAVs with high velocity.
Dynamics and control of a tri‐axis satellite attitude simulator
Authors: Shan Jinjun
Published: May 2010

Purpose

The purpose of this paper is to develop a tri‐axis spacecraft simulator to simulate the three‐axis attitude motion of a satellite and for ground‐based hardware‐in‐the‐loop simulation.

Design/methodology/approach

The structure of tri‐axis satellite attitude simulator is designed first. Full dynamic model is then derived. Based on the dynamic model, a simple proportional‐integral‐derivative controller is developed and applied to control the motion of simulator.

Findings

The effectiveness of the proposed simulator configuration has been verified through numerical simulations. The tri‐axis simulator can follow the satellite attitude motion precisely.

Originality/value

This paper is valuable for researchers working on the development of tri‐axis spacecraft attitude simulator. This work is original. The simulator configuration has been applied to a satellite mission that was launched successfully in 2006.
Preliminary design correlations for twin civil turboprops and comparison with jet aircraft
Authors: Vouvakos Xenakis , Kallinderis Yannis , Menounou Pinelopi
Published: May 2010

Purpose

The purpose of this paper is to compare twin engine civil turboprop aircraft with their jet engine counterparts; to simplify the preliminary design process and the initial evaluation of twin civil turboprop aircraft; to include noise level consideration in the preliminary design; and to form a current database of design parameters for representative civil turboprop aircraft.

Design/methodology/approach

The paper finds linear correlations between key design parameters. It compares the corresponding correlations for turboprop and jet engine aircraft.

Findings

The paper finds direct linear relationships between design parameters including noise levels; simplified preliminary design process; and differences in the sensitivity of design parameters between turboprop and jet aircraft.

Research limitations/implications

The turboprop aircraft database needs to be expanded. Also, investigation of non‐linear relations between design parameters is a next step.

Practical implications

Quick assessment and comparisons of existing designs is an outcome. Also, the preliminary design process is simplified and expedited. Lastly, noise regulations can affect the design right from the beginning and not at a later stage.

Originality/value

New correlations which simplify the current procedures for preliminary design of twin civil turboprop aircraft. In addition, the noise is included right from the beginning of the design. Direct comparison between turboprop and jet aircraft afforded via their correlated preliminary design parameters. Finally, a database of twin turboprops is formed with specially selected aircraft that are current and cover a wide spectrum of sizes.
From inspired teaching to effective knowledge work and back again
Authors: Eschenbach Sebastian
Published: May 2010

Purpose

The emerging knowledge societies will – besides many other dramatic changes – see a teaching revolution. This paper seeks to propose quality standards for this new type of teaching.

Design/methodology/approach

The paper argues that Peter Drucker experienced much of what he later came to call the principles of self management and effective knowledge work as a boy aged nine or ten at the Schwarzwald School – an utterly exceptional, progressive elementary school in Vienna. Given these astonishing similarities, this school's avant‐garde approach to teaching might just provide some insights into what effective teaching for a future knowledge society should be like. The paper is based to a large extent on accounts by and about the almost forgotten school's owner‐manager Eugenie Schwarzwald, some of which were made available only recently in the course of several biographical research projects dealing with this revolutionary pedagogue and social entrepreneur.

Findings

Firstly, the paper identifies similarities between the teaching practice at Eugenie Schwarzwald's schools, her approach to leadership on the one hand, and Drucker's principles of effective management and knowledge work on the other. Secondly, it concludes that in a knowledge society both effective management and teaching need to be extensively individualised services – much more than in an industrial mass society.

Practical implications

Combined, Schwarzwald's practice and Drucker's teachings challenge some seemingly up‐to‐date practices in both higher education and corporate personnel development, and helps in understanding what actually produces effective personal learning for the rapidly changing knowledge economies of the twenty‐first century.

Originality/value

The paper introduces selective aspects of progressive education to the field of management.
The art of managing for the future: leadership of turbulence
Authors: Lane David A. , Down Martin
Published: May 2010

Purpose

The paper aims to explore themes in Drucker's work which provide messages for current turbulent times. Based on a literature review of both Drucker's work and contemporary studies in the field of complexity theory the paper's aim is to explore turbulence as a feature of levels of agreement for objectives and predictability of outcome. Drucker's concept of management as a social enterprise is seen as central together with his warning that the tools and techniques of management should not obscure its purpose.

Design/methodology/approach

The paper provides a literature review and a brief case study. The review identifies that contemporary complexity theory can be used to explore Drucker's work on turbulence. The case study shows how approaches based on dialogue can enable conflicting objectives to be explored and agreed outcomes achieved.

Findings

The paper concludes that in turbulent times Drucker's concept of management as a social enterprise forms a core framework that can be used within complex situations to agree objectives through dialogue.

Originality/value

This paper uniquely links Drucker's work with contemporary complexity theory.
The challenge to rekindle China's innovative spirit
Authors: Kriz Anton
Published: May 2010

Purpose

China has become an economic powerhouse in historic terms but there are a number of challenges to its continued prosperity. The aim of this paper is to more fully understand China's propensity for creative innovation, which is seen as an important next stage in its continued development.

Design/methodology/approach

The paper is conceptual but uses historical and secondary data to support its assumptions. The paper was written in conjunction with the 1st Global Peter F. Drucker Forum (celebrating 100 years since his birth) and attempts to continue his challenge of “the hard work of thinking”.

Findings

China has a long history of successful innovation. However, Confucian belief, a single despot and a closing off to the rest of the world have thwarted its innovative edge. The key to rekindling the entrepreneurial spirit is seen largely as an internal battle based on the state's ability to balance the institution of government with the needs of a burgeoning prospective creative class. This paper identifies that much of this change will rely on quality‐related developments rather than simply investments of financial capital.

Originality/value

The ability to create new things is a challenge to developing economies that rely on low cost and imitation. China's success in innovation will have substantial implications for developed nations both economically and geo‐politically. China wants to be a significant player on a global scale and this paper sheds light on its potential to achieve such an objective. Through traversing China's innovative landscape, this paper also enlightens the field of management on key aspects of China's innovative past, present and future.
HKSAR government civil servants: a non‐Drucker organisation?
Authors: Kai Pong Leung Tony , Adams John
Published: May 2010

Purpose

Peter F. Drucker (1909‐2005) was an influential modern management theorist. This paper, however, aims to challenge his diagnosis and prescriptions on the public sector for over‐simplifying several complex issues and not being sufficiently comprehensive. With the support of the empirical findings of a survey in the government of Hong Kong Special Administrative Region (HKSARG), the authors seek to supplement Drucker's discussion on government and to propose managerial actions for implementing change.

Design/methodology/approach

An e‐mail questionnaire survey of 700 randomly selected government employees in Hong Kong was conducted. Additional information was gathered from senior management to validate the survey results.

Findings

In line with Drucker, HKSARG employees, as a whole, are reluctant to change. But statistical tests show that there are heterogeneous behavioural groups. Specifically, younger and more educated staff are more willing to change. The existence of these groups has both practical and managerial implications for implementing change.

Research limitations/implications

The usable sample is relatively small (n=66).

Practical implications

The government should not be viewed and understood unidirectionally. Management should target the younger and more educated users first to build up sufficient user mass and adopt peer pressure for a more successful level of implementation of IT usage across all staff. Job rotation and flexible entry and exit options are worth considering, too.

Originality/value

This research validates empirically the nature of HKSARG. It demonstrates that researchers' challenges to Drucker's views on government are well founded. More research on the characteristics of the public sector is required for better understanding of the real nature of these large, bureaucratic organisations.
Effect of particle transient motion on lubrication
Authors: Haiyan Han , Youyun Zhang , Zhenyuan Zhong
Published: May 2010

Purpose

The purpose of this paper is to analyze the influence of particle motion on the lubrication characteristics. The dynamics of the particle in the lubricant is also studied.

Design/methodology/approach

The dynamics of the particle is studied using Newton's second law. The particle dynamic equation is solved to determine the particle velocity, angular velocity, and location. The modified Reynolds equation is solved in couple with particle motion to determine the film pressure and velocity.

Findings

The motion of a particle suspended in the lube oil is clarified. The initial relative velocity between the particle and the fluid has a significant effect on the lubrication. For the same particle location and velocity, the larger particle or the closer distance between particle center and lower plate has greater effects on the film pressure.

Research limitations/implications

The influence of the particle geometry on the lubrication is neglected in the study because of the small size of the particle, this neglect is idealized. Further study will take the effects of the particle geometry into consideration.

Originality/value

The paper provides the motion of the particle in the lubricant, and the modified Reynolds equation considering the particle translation as well as rotation is derived.
Oil‐ and water‐based continuous control valve
Authors: Majdic Franc , Pezdirnik Jozef
Published: May 2010

Purpose

Environmental protection regulations are becoming increasingly strict. Using water instead of a hydraulic mineral or biodegradable oil in power‐control hydraulic systems is a very positive step towards complying with these regulations. Since water hydraulics has many specifics, primarily related to lower viscosity and lubricity of water compared to oil, which greatly affects the leakage, and even more the friction and wear in these systems, a dedicated test rig is required for performing research with the real‐scale components. The purpose of this paper is to present some preliminary representative results on dynamic responses of the two hydraulic circuits with and without a mass load.

Design/methodology/approach

The paper presents the newly developed dedicated test rig and its dynamic characteristics when used with water and oil as hydraulic fluid. Hydraulic pressures and motions of spool and piston in the two different fluids were of special interest.

Findings

The results clearly show their dependence on friction properties of selected materials in different hydraulic fluids. While the oil valve worked perfectly, water valve has some irregularity, linked with the small gap, the shape irregularity, the surface roughness and the poorer lubrication conditions in the water hydraulics compared to the oil system.

Originality/value

The observed irregularity of the movement of the spool in the water hydraulic valve has almost no influence on the movement of the piston rod of the water cylinder, which is a very promising result for future research on water hydraulics.
Minimization of power loss in tilting‐pad journal bearings
Authors: Saruhan Hamit
Published: May 2010

Purpose

The purpose of this paper is to implement an optimization approach for the tilting‐pad journal bearing using the genetic algorithm (GA), and compare the results with the method of feasible design (MFD).

Design/methodology/approach

The optimum design of a five‐pad tilting‐pad bearing is studied for the optimal performance, considering system minimum power loss along with design criteria such as: fluid film thickness, film temperature, and film pressure with respect to design variables consisting of pad axial length to journal diameter ratio, pad arc length, bearing radial clearance, pad offset factor, and pad preload factor.

Findings

The algorithms are repeated until no search direction can be found that will improve objective function without violating the constraints. Thus, the algorithms are performed for complete search to get the best possible solution of the design. The comparison mainly focuses on the empirical solutions. The GA obtained reasonably good results for the objective function and comparable to the MFD.

Originality/value

The availability of the GA is certainly of value because it allows the exploration of many different configurations of design variables and therefore also contributes to the better knowledge of the rotor‐bearing system behavior in general.