bluuebunny/crossref_metadata_2025 huggingface dataset:
A homologous genetic basis of the murine
cpfl1
mutant and human achromatopsia linked to mutations in the
PDE6C
gene
Authors: Chang Bo , Grau Tanja , Dangel Susann , Hurd Ron , Jurklies Bernhard , Sener E. Cumhur , Andreasson Sten , Dollfus Helene , Baumann Britta , Bolz Sylvia , Artemyev Nikolai , Kohl Susanne , Heckenlively John , Wissinger Bernd
Published: November 2009

Retinal cone photoreceptors mediate fine visual acuity, daylight vision, and color vision. Congenital hereditary conditions in which there is a lack of cone function in humans cause achromatopsia, an autosomal recessive trait, characterized by low vision, photophobia, and lack of color discrimination. Herein we report the identification of mutations in the
PDE6C
gene encoding the catalytic subunit of the cone photoreceptor phosphodiesterase as a cause of autosomal recessive achromatopsia. Moreover, we show that the spontaneous mouse mutant
cpfl1
that features a lack of cone function and rapid degeneration of the cone photoreceptors represents a homologous mouse model for
PDE6C
associated achromatopsia.
Kinetic enhancement of NF-κB·DNA dissociation by IκBα
Authors: Bergqvist Simon , Alverdi Vera , Mengel Benedicte , Hoffmann Alexander , Ghosh Gourisankar , Komives Elizabeth A.
Published: November 2009

A hallmark of the NF-κB transcription response to inflammatory cytokines is the remarkably rapid rate of robust activation and subsequent signal repression. Although the rapidity of postinduction repression is explained partly by the fact that the gene for IκBα is strongly induced by NF-κB, the newly synthesized IκBα still must enter the nucleus and compete for binding to NF-κB with the very large number of κB sites in the DNA. We present results from real-time binding kinetic experiments, demonstrating that IκBα increases the dissociation rate of NF-κB from the DNA in a highly efficient kinetic process. Analysis of various IκB mutant proteins shows that this process requires the C-terminal PEST sequence and the weakly folded fifth and sixth ankyrin repeats of IκBα. Mutational stabilization of these repeats reduces the efficiency with which IκBα enhances the dissociation rate.
Hypoxia-induced pathological angiogenesis mediates tumor cell dissemination, invasion, and metastasis in a zebrafish tumor model
Authors: Lee Samantha Lin Chiou , Rouhi Pegah , Jensen Lasse Dahl , Zhang Danfang , Ji Hong , Hauptmann Giselbert , Ingham Philip , Cao Yihai
Published: November 2009

Mechanisms underlying pathological angiogenesis in relation to hypoxia in tumor invasion and metastasis remain elusive. Here, we have developed a zebrafish tumor model that allows us to study the role of pathological angiogenesis under normoxia and hypoxia in arbitrating early events of the metastatic cascade at the single cell level. Under normoxia, implantation of a murine T241 fibrosarcoma into the perivitelline cavity of developing embryos of transgenic
fli1:EGFP
zebrafish did not result in significant dissemination, invasion, and metastasis. In marked contrast, under hypoxia substantial tumor cells disseminated from primary sites, invaded into neighboring tissues, and metastasized to distal parts of the fish body. Similarly, expression of the hypoxia-regulated angiogenic factor, vascular endothelial growth factor (VEGF) to a high level resulted in tumor cell dissemination and metastasis, which correlated with increased tumor neovascularization. Inhibition of VEGF receptor signaling pathways by sunitinib or VEGFR2 morpholinos virtually completely ablated VEGF-induced tumor cell dissemination and metastasis. To the best of our knowledge, hypoxia- and VEGF-induced pathological angiogenesis in promoting tumor dissemination, invasion, and metastasis has not been described perviously at the single cell level. Our findings also shed light on molecular mechanisms of beneficial effects of clinically available anti-VEGF drugs for cancer therapy.
‘We hardly knew what we should pay attention to first’: Mozart the Performer-Composer at Work on the Viennese Piano Concertos
Authors: Keefe Simon P.
Published: November 2009

Late eighteenth-century writings bear witness to Mozart's extraordinary skills as a performer-composer. But this dual status has yet to exert a serious influence on our understanding of Mozart's piano concertos. An examination of changes to the autograph scores of his Viennese works catches him in the act of negotiating performance needs as soloist and compositional needs as author. His acute attention to detail and his intense personal involvement and commitment – evident in written testimony and in alterations to the autographs – reveal a performer-composer intent on harnessing very specific musical events (sounds, timbres, instrumental and solo effects) to more general ends that ultimately invite listeners to perceive performance and composition as mutually reinforcing features of a complete musical experience. Modern performers trying to recreate the performer-composer experience – soloists and orchestral instrumentalists alike – are thus encouraged to put sounds, textures and effects centre stage in their own interpretations of Mozart's concertos.
The Regime's ‘Musical Weapon’ Transformed: The Reception of Johann Strauss Sr's Radetzky March Before and After the First World War
Authors: Lang Zoë
Published: November 2009

Johann Strauss Sr's most famous composition, his 1848 Radetzky March, was premièred during revolutionary times. The March soon became a standard piece for Habsburg bands in the nineteenth century and was considered ideal for fostering patriotic sentiments at the start of the First World War. After the Great War, however, commentators portrayed the work very differently. No longer a part of contemporary culture, the Radetzky March now belonged to a bygone era. Biographers of the Strauss family found this work to be proof of Strauss Sr's support for the conservatives during the Revolution, a claim not supported by evidence. More generally, treating the piece as a relic from another age transformed it into a marker of nostalgia in the 1930s, as is best demonstrated in Joseph Roth's novel, Radetzkymarsch (1932).
Material and History in the Aesthetics of ‘Serielle Musik’
Authors: Zagorski Marcus
Published: November 2009

Attempts to promote the aesthetic prestige of serial and post-serial music were grounded in theories of material and philosophies of history. As composers explored new aspects of sound and subjected these to rational organization, they saw themselves pushing history forward, with new musical materials providing physical evidence for each new stage of progress. The continual search for new material fashioned a thread that bound together vastly different personalities, and similar ideas about material and history linked a diversity of approaches to, and reactions against, serialism. Believing themselves to be renouncing a subjectivity made untrustworthy by the recent past, many post-war composers turned to something larger to guide their compositional decisions: to the objective dictate of historical progress. Such deference to a fictitious construction of history veiled subjective aesthetic preferences and provided a way to legitimate new techniques with the authority of ‘higher laws’. This article reconsiders post-war serialism in central Europe from the perspective of theories of material and examines how these theories coupled aesthetic and social concerns with philosophy of history to justify compositional techniques.
Optimizing Energy-Efficient Reconstruction of Mobile Point Source in Sensor Networks
Authors: Chen Zhi-Gang , Zhao Ming , Guo Ying , Deng Xiao-Heng
Published: November 2009

To obtain accurate information about the interested physical phenomenon, many nodes should be deployed and collaborated to extract data about the event source. This article proposes a Low Power Self Scheduling protocol for mobile point source reconstruction. The motivation is clear, to provide high level QoS (reconstruction distortion) and reduce energy consumption. This article first obtains a distance to the event source, in which all sensing reports are collected to minimize the reconstruction distortion. This distance is relatively constant under different network densities. Then the mobility of the event source is considered. Sensor nodes are self-scheduled to join or leave the representative nodes group, which guarantee that those appropriate nodes will always be the group member. Simulation validates the effectiveness of the presented scheme.
Energy Efficient Residual Energy Monitoring in Wireless Sensor Networks
Authors: Chan Edward , Han Song
Published: November 2009

A crucial issue in the management of sensor networks is the continuous monitoring of residual energy level of the sensors in the network. With the large number of sensors in a typical network, the energy monitoring process can itself be very energy intensive. In this article, we propose a hierarchical approach to construct a continuous energy map of a sensor network. Our method consists of a topology discovery and clustering phase, followed by an aggregation phase when energy information collected is abstracted and merged into energy contours in which nodes with similar energy level are grouped into the same region. The topology of the monitoring tree is restructured periodically to distribute energy cost among all nodes fairly, which helps to reduce the impact of the monitoring scheme on the lifetime of the sensor network. Simulation results indicate that our method is able to generate accurate energy maps with much lower energy cost compared with traditional monitoring approaches.
Adaptive Energy-Aware Gathering Strategy for Wireless Sensor Networks
Authors: Saad E. M. , Awadalla M. H. , Darwish R. R.
Published: November 2009

Energy hole problem is considered one of the most severe threats in wireless sensor networks. In this paper the idea of exploiting sink mobility for the purpose of culling the energy hole problem in hierarchical large-scale wireless sensor networks based on bees algorithm is presented. In the proposed scheme, a mobile sink equipped with a powerful transceiver and battery, traverses the entire field, and periodically gathers data from network cluster heads. The mobile sink follows an adaptive gathering strategy resilient to both connected and disconnected networks. The proposed gathering strategy geared to eliminate multihop relays required by all cluster heads to reach the mobile sink, balancing the traffic load across all network heads, meanwhile, reducing the loss that data may incur due to buffer overflow. Furthermore, enabling the mobile sink to navigate safely within cluttered and uncluttered fields augments the proposed gathering strategy. Extensive simulations are conducted in order to validate the effectiveness of the proposed strategy. The achieved results show an improvement in overall system performance compared to other mobility strategies.
Improved Key Predistribution Scheme in Wireless Sensor Networks Using Cell Splitting in Hexagonal Grid Based Deployment Model
Authors: Kishore R. , Radha S. , Rose S. G. Hymlin
Published: November 2009

Security in wireless sensor networks is an upcoming field which is quite different from traditional network security mechanisms. Many applications are dependent on the secure operation of a wireless sensor network, and have serious effects if the network is disrupted. Therefore, it is necessary to protect communication between sensor nodes. Key management plays an essential role in achieving security in wireless sensor networks. To achieve security, various key predistribution schemes have been proposed without deployment knowledge. Deployment knowledge can benefit the key predistribution scheme, as the nodes that are likely to be neighbors of each sensor node are assumed, and hence each node does not need to waste its memory to store unnecessary secret information. However, the existing key predistribution schemes require more memory and larger transmission range to achieve the desired connectivity. In order to enhance secure communication among sensor nodes, grid and hexagon deployment models are used. In both the deployment models, the sensor field is divided into equal grids. The keys are distributed from a large key pool randomly and pairwise keys are generated for each pair of sensor nodes. Once the pairwise keys are generated among neighboring nodes, they establish a secure connection and transmit data. We propose a new scheme based on cell splitting concept to improve the security level, in which a hexagon is subdivided in to smaller groups. The performance is evaluated in terms of connectivity and resilience against node capture. The analysis show that the performance is better using cell splitting concept compared to normal hexagon based scheme.
Discerning Elementary Particles
Authors: Muller F. A. , Seevinck M. P.
Published: November 2009

We maximally extend the quantum-mechanical results of Muller and Saunders (2008) establishing the ‘weak discernibility’ of an arbitrary number of similar fermions in finite-dimensional Hilbert spaces. This confutes the currently dominant view that (A) the quantum-mechanical description of similar particles conflicts with Leibniz's Principle of the Identity of Indiscernibles (PII); and that (B) the only way to save PII is by adopting some heavy metaphysical notion such as Scotusian haecceitas or Adamsian primitive thisness. We take sides with Muller and Saunders (2008) against this currently dominant view, which has been expounded and defended by many.
Kuhn's Evolutionary Epistemology and Its Being Undermined by Inadequate Biological Concepts
Authors: Renzi Barbara Gabriella
Published: November 2009

Kuhn made two attempts at providing an evolutionary analogy for scientific change. The first attempt, in The Structure of Scientific Revolutions, is very brief and unstructured; in this article I discuss some of its weaknesses. Alexander Bird takes this attempt more seriously and provides a criticism based on oversimplified evolutionary assumptions. These assumptions prove to be inadequate for the second, more articulate, evolutionary analogy suggested by Kuhn in “The Road since Structure.” I argue, however, that this second Kuhnian attempt is undermined by his inadequate view of biological progress and by his misunderstanding of the concept of ecological niche.
Nilpotent orbits in the dual of classical Lie algebras in characteristic 2 and the Springer correspondence
Authors: Xue Ting
Published: November 2009

Let

G
G

be a simply connected algebraic group of type

B
B

,

C
C

or

D
D

over an algebraically closed field of characteristic

2
2

. We construct a Springer correspondence for the dual vector space of the Lie algebra of

G
G

. In particular, we classify the nilpotent orbits in the duals of symplectic and orthogonal Lie algebras over algebraically closed or finite fields of characteristic

2
2

.
SimBoolNet—a Cytoscape plugin for dynamic simulation of signaling networks
Authors: Zheng Jie , Zhang David , Przytycki Pawel F. , Zielinski Rafal , Capala Jacek , Przytycka Teresa M.
Published: November 2009

Summary: SimBoolNet is an open source Cytoscape plugin that simulates the dynamics of signaling transduction using Boolean networks. Given a user-specified level of stimulation to signal receptors, SimBoolNet simulates the response of downstream molecules and visualizes with animation and records the dynamic changes of the network. It can be used to generate hypotheses and facilitate experimental studies about causal relations and crosstalk among cellular signaling pathways.

Availability: SimBoolNet package (with manual) is freely available at http://www.ncbi.nlm.nih.gov/CBBresearch/Przytycka/SimBoolNet

Contact:  przytyck@ncbi.nlm.nih.gov; zhengj@ncbi.nlm.nih.gov
The obesity paradox in stable chronic heart failure does not persist after matching for indicators of disease severity and confounders
Authors: Frankenstein Lutz , Zugck Christian , Nelles Manfred , Schellberg Dieter , Katus Hugo A. , Remppis B. Andrew
Published: November 2009

Aims

To verify whether controlling for indicators of disease severity and confounders represents a solution to the obesity paradox in chronic heart failure (CHF).

Methods and results

From a cohort of 1790 patients, we formed 230 nested matched triplets by individually matching patients with body mass index (BMI) > 30 kg/m2 (Group 3), BMI 20–24.9 k/m2 (Group 1) and BMI 25–29.9 kg/m2 (Group 2), according to NT‐proBNP, age, sex, and NYHA class (triplet = one matched patient from each group). Although in the pre‐matching cohort, BMI group was a significant univariable prognostic indicator, it did not retain significance [heart rate (HR): 0.91, 95% CI: 0.78–1.05, χ2: 1.67] when controlled for group propensities as covariates. Furthermore, in the matched cohort, 1‐year mortality and 3‐year mortality did not differ significantly. Here, BMI again failed to reach statistical significance for prognosis, either as a continuous or categorical variable, whether crude or adjusted. This result was confirmed in the patients not selected for matching. NT‐proBNP, however, remained statistically significant (log(NT‐proBNP): HR: 1.49, 95% CI: 1.13–1.97, χ2: 7.82) after multivariable adjustment.

Conclusion

The obesity paradox does not appear to persist in a matched setting with respect to indicators of disease severity and other confounders. NT‐proBNP remains an independent prognostic indicator of adverse outcome irrespective of obesity status.
The Transcriptional Activator rfiA Is Quorum-Sensing Regulated by Cotranscription with the luxI Homolog pcoI and Is Essential for Plant Virulence in Pseudomonas corrugata
Authors: Licciardello Grazia , Bertani Iris , Steindler Laura , Bella Patrizia , Venturi Vittorio , Catara Vittoria
Published: November 2009

The gram-negative phytopathogen Pseudomonas corrugata has an acyl-homoserine lactone (AHL) quorum-sensing (QS) system called PcoI/PcoR that is involved in virulence on tomato. This work identifies, downstream of pcoI, a gene designated rfiA, which we demonstrate is directly linked to QS by cotranscription with pcoI. The deduced RfiA protein contains a DNA-binding domain characteristic of the LuxR family but lacks the autoinducer-binding terminus characteristic of the QS LuxR-family proteins. We also identified, downstream of rfiA, an operon designated pcoABC, encoding for the three components of a tripartite resistance nodulation-cell-division (RND) transporter system. The expression of pcoABC is regulated by RfiA. We found that lipodepsipeptide (LDP) production is cell density dependent and mutants of pcoI, pcoR, and rfiA are unable to inhibit the growth of the LDP-sensitive microorganisms Rhodotorula pilimanae and Bacillus megaterium. P. corrugata rfiA mutants were significantly reduced in their ability to cause necrosis development in tomato pith. In addition, it was established that PcoR in the absence of AHL also played a role in virulence on tomato. A model for the role of PcoI, PcoR, and RfiA in tomato pith necrosis is presented.
Nodulation Gene Mutants of Mesorhizobium loti R7A—nodZ and nolL Mutants Have Host-Specific Phenotypes on Lotus spp.
Authors: Rodpothong Patsarin , Sullivan John T. , Songsrirote Kriangsak , Sumpton David , Cheung Kenneth W. J.-T. , Thomas-Oates Jane , Radutoiu Simona , Stougaard Jens , Ronson Clive W.
Published: November 2009

Rhizobial Nod factors induce plant responses and facilitate bacterial infection, leading to the development of nitrogen-fixing root nodules on host legumes. Nodule initiation is highly dependent on Nod-factor structure and, hence, on at least some of the nodulation genes that encode Nod-factor production. Here, we report the effects of mutations in Mesorhizobium loti R7A nodulation genes on nodulation of four Lotus spp. and on Nod-factor structure. Most mutants, including a ΔnodSΔnolO double mutant that produced Nod factors lacking the carbamoyl and possibly N-methyl groups on the nonreducing terminal residue, were unaffected for nodulation. R7AΔnodZ and R7AΔnolL mutants that produced Nod factors without the (acetyl)fucose on the reducing terminal residue had a host-specific phenotype, forming mainly uninfected nodule primordia on Lotus filicaulis and L. corniculatus and effective nodules with a delay on L. japonicus. The mutants also showed significantly reduced infection thread formation and Nin gene induction. In planta complementation experiments further suggested that the acetylfucose was important for balanced signaling in response to Nod factor by the L. japonicus NFR1/NFR5 receptors. Overall the results reveal differences in the sensitivity of plant perception with respect to signaling leading to root hair deformation and nodule primordium development versus infection thread formation and rhizobial entry.
Integration of Ethylene and Jasmonic Acid Signaling Pathways in the Expression of Maize Defense Protein Mir1-CP
Authors: Ankala A. , Luthe D. S. , Williams W. P. , Wilkinson J. R.
Published: November 2009

In plants, ethylene and jasmonate control the defense responses to multiple stressors, including insect predation. Among the defense proteins known to be regulated by ethylene is maize insect resistance 1-cysteine protease (Mir1-CP). This protein is constitutively expressed in the insect-resistant maize (Zea mays) genotype Mp708; however, its abundance significantly increases during fall armyworm (Spodoptera frugiperda) herbivory. Within 1 h of herbivory by fall armyworm, Mir1-CP accumulates at the feeding site and continues to increase in abundance until 24 h without any increase in its transcript (mir1) levels. To resolve this discrepancy and elucidate the role of ethylene and jasmonate in the signaling of Mir1-CP expression, the effects of phytohormone biosynthesis and perception inhibitors on Mir1-CP expression were tested. Immunoblot analysis of Mir1-CP accumulation and quantitative reverse-transcriptase polymerase chain reaction examination of mir1 levels in these treated plants demonstrate that Mir1-CP accumulation is regulated by both transcript abundance and protein expression levels. The results also suggest that jasmonate functions upstream of ethylene in the Mir1-CP expression pathway, allowing for both low-level constitutive expression and a two-stage defensive response, an immediate response involving Mir1-CP accumulation and a delayed response inducing mir1 transcript expression.
Carbon Metabolism and Bacteroid Functioning Are Involved in the Regulation of Nitrogen Fixation inMedicago truncatulaUnder Drought and Recovery
Authors: Larrainzar Estíbaliz , Wienkoop Stefanie , Scherling Christian , Kempa Stefan , Ladrera Rubén , Arrese-Igor Cesar , Weckwerth Wolfram , González Esther M.
Published: November 2009

Regulation of symbiotic nitrogen fixation (SNF) during drought stress is complex and not yet fully understood. In the present work, the involvement of nodule C and N metabolism in the regulation of SNF in Medicago truncatula under drought and a subsequent rewatering treatment was analyzed using a combination of metabolomic and proteomic approaches. Drought induced a reduction of SNF rates and major changes in the metabolic profile of nodules, mostly an accumulation of amino acids (Pro, His, and Trp) and carbohydrates (sucrose, galactinol, raffinose, and trehalose). This accumulation was coincidental with a decline in the levels of bacteroid proteins involved in SNF and C metabolism, along with a partial reduction of the levels of plant sucrose synthase 1 (SuSy1). In contrast, the variations in enzymes related to N assimilation were found not to correlate with the reduction in SNF, suggesting that these enzymes do not have a role in the regulation of SNF. Unlike the situation in other legumes such as pea and soybean, the drought-induced inhibition of SNF in M. truncatula appears to be caused by impairment of bacteroid metabolism and N2-fixing capacity rather than a limitation of respiratory substrate.
Novel Genes of Fusarium graminearum That Negatively Regulate Deoxynivalenol Production and Virulence
Authors: Gardiner Donald M. , Kazan Kemal , Manners John M.
Published: November 2009

Fusarium head blight of wheat, caused by Fusarium graminearum, is a serious disease resulting in both reduced yields and contamination of grain with trichothecene toxins, with severe consequences for mammalian health. Recently, we have identified several related amine compounds such as agmatine and putrescine that promote the production of high levels of trichothecene toxins, such as deoxynivalenol (DON), in culture by F. graminearum and F. sporotrichioides. Here, a global analysis of fungal gene expression using the Affymetrix Fusarium GeneChip during culture under DON-inducing conditions compared with noninducing conditions is reported. Agmatine differentially regulated a large number of fungal genes, including both known and previously uncharacterized putative secondary metabolite biosynthetic gene clusters. In silico prediction of binding sites for the transcriptional regulator (TRI6) controlling TRI gene expression and gene expression analysis in a TRI6 mutant of F. graminearum showed that three of the differentially regulated genes were under the control of TRI6. Gene knock-out mutations of two of these genes resulted in mutants with massively increased production of DON and increased aggressiveness toward wheat. Our results not only identify a novel mechanism of negative regulation of DON production and virulence in F. graminearum but also point out the potential of this pathogen to evolve with an ability to produce massively increased amounts of toxins and increased virulence.
Analysis of a Blumeria graminis-Secreted Lipase Reveals the Importance of Host Epicuticular Wax Components for Fungal Adhesion and Development
Authors: Feng Jie , Wang Feng , Liu Guosheng , Greenshields David , Shen Wenyun , Kaminskyj Susan , Hughes Geoff R. , Peng Youliang , Selvaraj Gopalan , Zou Jitao , Wei Yangdou
Published: November 2009

The biotrophic powdery mildew fungus Blumeria graminis releases extracellular materials to the surface of fungal infection structures that facilitate anchoring them to hydrophobic plant surfaces prior to infection; however, the chemistry of fungal adhesives and the mechanism of adhesion remain largely unclear. Expressed sequence tag analysis led to identification of a secreted lipase, Lip1, from B. graminis. Expression of LIP1 is dramatically upregulated during the early stages of fungal development. Lip1, secreted to the surface of fungal cell walls, possesses lipolytic activity against a broad range of glycerides and releases alkanes and primary fatty alcohols from the epicuticular wax of wheat leaves. Of the epicuticular wax components released by Lip1 activity, long-chain alkanes are the most efficient cues for triggering appressorium formation. Pretreatment of wheat leaves with Lip1, thereby removing leaf surface wax, severely compromises components of fungal pathogenicity, including conidial adhesion, appressorium formation, and secondary hypha growth. Our data suggest that Lip1 activity releases cues from the host surface to promote pathogen development and infection.
The RAP1 Gene Confers Effective, Race-Specific Resistance to the Pea Aphid in Medicago truncatula Independent of the Hypersensitive Reaction
Authors: Stewart Sophie Alice , Hodge Simon , Ismail Nurul , Mansfield John W. , Feys Bart J. , Prospéri Jean-Marie , Huguet Thierry , Ben Cécile , Gentzbittel Laurent , Powell Glen
Published: November 2009

Plant resistance to pathogens is commonly associated with a hypersensitive response (HR), but the degree to which the HR is responsible for incompatibility is subject to debate. Resistance to aphids is likely to share features with resistance to pathogens but is less well understood. Here, we report effective resistance to the pea aphid Acyrthosiphon pisum in Medicago truncatula. Aphids lost weight and died rapidly (within two days) on the resistant genotype Jemalong, which developed necrotic lesions following infestation. Lesions were induced by nonvascular intracellular stylet punctures by aphids, remained localized to the site of stylet entry, stained for the presence of reactive oxygen species, and were similar to the HR induced by the bacterial pathogen Pseudomonas syringae pv. phaseolicola. The implication that aphid-induced lesions confer resistance was tested by quantitative trait loci analysis using recombinant inbred lines derived from a cross between Jemalong and the susceptible genotype DZA315.16. One major locus, RAP1, was identified that was sufficient to confer race-specific resistance against the pea aphid and was mapped to the middle of chromosome 3. Surprisingly, a separate locus, mapping to the top of chromosome 3, governed aphid-induced HR, indicating that the HR-like lesions are not required for RAP1-mediated aphid resistance.
Production of Succinoglycan Polymer in Sinorhizobium meliloti Is Affected by SMb21506 and Requires the N-terminal Domain of ExoP
Authors: Jofré Edgardo , Becker Anke
Published: November 2009

The protein tyrosine kinase ExoP, consisting of an N-terminal periplasmic and a C-terminal cytoplasmic domain, is important for polymerization of the exopolysaccharide succinoglycan (EPS I) in Sinorhizobium meliloti. We analyzed the contribution of the ExoP paralogs ExoP2 and SMb21506 to the production of the high molecular weight (HMW) form of EPS I. ExoP2, though not contributing to EPS I or lipopolysaccharide biosynthesis, showed increased expression at high osmolarity and was expressed in Medicago sativa nodules, suggesting an involvement in the synthesis of an as-yet-unidentified polysaccharide. Furthermore, a mutation in SMb21506 affected the production of HMW EPS I, particularly in the absence of the C-terminal ExoP domain. High salinity induced the production of HMW EPS I by the wild type and mutants whereas high osmolarity had the opposite effect. It was shown that ExoP localizes at the inner membrane of S. meliloti cells. Tyrosine phosphorylation of the C-terminal domain was strongly increased by amino acid substitutions in the polysaccharide co-polymerase motif (formerly proline-rich motif) located in the N-terminal domain, suggesting that this phosphorylation could be modulated by conformational changes of the N-terminal domain. Moreover, deletion of a coiled-coil motif present in the N-terminal domain abolished phosphorylation and EPS I production and, consequently, the ability to nodulate M. sativa.
Ecological speciation in marinev.freshwater fishes
Authors: Puebla O.
Published: November 2009

Absolute barriers to dispersal are not common in marine systems, and the prevalence of planktonic larvae in marine taxa provides potential for gene flow across large geographic distances. These observations raise the fundamental question in marine evolutionary biology as to whether geographic and oceanographic barriers alone can account for the high levels of species diversity observed in marine environments such as coral reefs, or whether marine speciation also operates in the presence of gene flow between diverging populations. In this respect, the ecological hypothesis of speciation, in which reproductive isolation results from divergent or disruptive natural selection, is of particular interest because it may operate in the presence of gene flow. Although important insights into the process of ecological speciation in aquatic environments have been provided by the study of freshwater fishes, comparatively little is known about the possibility of ecological speciation in marine teleosts. In this study, the evidence consistent with different aspects of the ecological hypothesis of speciation is evaluated in marine fishes. Molecular approaches have played a critical role in the development of speciation hypotheses in marine fishes, with a role of ecology suggested by the occurrence of sister clades separated by ecological factors, rapid cladogenesis or the persistence of genetically and ecologically differentiated species in the presence of gene flow. Yet, ecological speciation research in marine fishes is still largely at an exploratory stage. Cases where the major ingredients of ecological speciation, namely a source of natural divergent or disruptive selection, a mechanism of reproductive isolation and a link between the two have been explicitly documented are few. Even in these cases, specific predictions of the ecological hypothesis of speciation remain largely untested. Recent developments in the study of freshwater fishes illustrate the potential for molecular approaches to address specific questions related to the ecological hypothesis of speciation such as the nature of the genes underlying key ecological traits, the magnitude of their effect on phenotype and the mechanisms underlying their differential expression in different ecological contexts. The potential provided by molecular studies is fully realized when they are complemented with alternative (e.g. ecological, theoretical) approaches.
Characterization and expression of a myosin heavy–chain isoform in juvenile walleye Sander vitreus
Authors: Dhillon R. S. , Esbaugh A. J. , Wang Y. S. , Tufts B. L.
Published: November 2009

In this study, myosin, the major component of myofibrillar protein in the skeletal muscle, was characterized and its expression was monitored during growth in juvenile walleye Sander vitreus. First, the coding region of myosin heavy chain (MyHC) from the fast skeletal muscle of walleye was amplified by long‐distance PCR using a full‐length cDNA. Phylogenetic analysis was used to determine the evolutionary relationship of this S. vitreus myosin sequence to other vertebrate myosin sequences. Next, it was established that the myosin isoform was most prevalent in the white muscle, compared with the red and cardiac muscle. Myosin expression was monitored over a series of experiments designed to influence growth. Specifically, change in MyHC mRNA was monitored after acute changes in feeding. Fish exposed to a one‐week fasting period showed significant decreases in MyHC mRNA levels by the end of the fast. The effect of feeding was also examined more closely over a 24 h period after feeding, but results showed no significant change in myosin expression levels through this time period. Finally, fish with higher growth rates had higher MyHC mRNA and protein expression levels. This study indicates that MyHC mRNA expression is sensitive to the factors that may influence growth in juvenile S. vitreus.
A cryptic lineage within the pupfish Cyprinodon dearborni suggests multiple colonizations of South America
Authors: Haney R. A. , Turner B. J. , Rand D. M.
Published: November 2009

The coastal South American species Cyprinodon dearborni contains two lineages distinct at both mitochondrial and nuclear loci. One appears to be a long‐term South American endemic, whereas the other is a more recent colonizer related to the widespread Cyprinodon variegatus.
Karyotypic diversity and evolution of seven mahseer species (Cyprinidae) from India
Authors: Mani I. , Kumar R. , Singh M. , Kushwaha B. , Nagpure N. S. , Srivastava P. K. , Murmu K. , Rao D. S. K. , Lakra W. S.
Published: November 2009

Mahseer is a group of fish species that are well known as food and game fishes. The taxonomy of the mahseer species is confusing owing to the morphological variations and habitat adaptation. Detailed karyomorphological investigations have been carried out in seven species of mahseer, using karyotyping, Ag‐NOR and fluorescent staining techniques. The basic diploid chromosome number (2n), in all mahseer species, was observed to be 100; however, the karyotype formula varied among the species, which were recorded as: 20m + 14sm + 22st + 44t (fundamental arm number, FN = 134) in Tor khudree; 22m + 24sm + 24st + 30t (FN = 146) in Tor mussullah; 12m + 22sm + 14st + 52t (FN = 134) in Tor putitora; 20m + 24sm + 24st + 32t (FN = 144) in Tor tor; 20m + 30sm + 24st + 26t (FN = 150) in Tor chelynoides; 20m + 20sm + 20st + 40t (FN = 140) in Tor progeneius; and 20m + 18sm + 14st + 48t (FN = 138) in Neolissochilus hexagonolepis. Silver staining of the chromosomes revealed the presence of multiple nucleolar organizer regions (NOR) in these mahseer species. The highest number of NORs was observed in T. tor (four pairs of chromosomes), whereas the other six species possessed Ag‐NOR signals on only two pairs of chromosomes. Although chromomycin A3 (CMA3) staining induced bright fluorescence signals on same Ag‐NORs sites, with CMA3, one additional signal was observed on the p arm of subtelocentric chromosomes in T. tor, T. chelynoides, T. progeneius and N. hexagonolepis, which may indicate the presence of inactive NOR in these species. The information on cytogenetic profile of these mahseer species is discussed in the light of cytotaxonomic implications and understanding the karyoevolution of these fish species.
Diversity and distribution of gynogenetic hybrids between Fundulus diaphanus and Fundulus heteroclitus in Porter's Lake (Nova Scotia) in relation to salinity
Authors: Mérette D. , Bourret A. , Turgeon J.
Published: November 2009

Unisexual hybrids between Fundulus diaphanus and Fundulus heteroclitus were found in low proportions at intermediate salinity in Porter's Lake, Nova Scotia. One clone accounted for 72% of the hybrids, with most other hybrids being different at a single microsatellite allele. This clone thrives over a wide range of salinities, suggesting a general‐purpose genotype.
Beyond aflatoxin: four distinct expression patterns and functional roles associated with Aspergillus flavus secondary metabolism gene clusters
Authors: GEORGIANNA D. RYAN , FEDOROVA NATALIE D. , BURROUGHS JAMES L. , DOLEZAL ANDREA L. , BOK JIN WOO , HOROWITZ‐BROWN SIGAL , WOLOSHUK CHARLES P. , YU JIUJIANG , KELLER NANCY P. , PAYNE GARY A.
Published: November 2009

Species of Aspergillus produce a diverse array of secondary metabolites, and recent genomic analysis has predicted that these species have the capacity to synthesize many more compounds. It has been possible to infer the presence of 55 gene clusters associated with secondary metabolism in Aspergillus flavus; however, only three metabolic pathways—aflatoxin, cyclopiazonic acid (CPA) and aflatrem—have been assigned to these clusters. To gain an insight into the regulation of and to infer the ecological significance of the 55 secondary metabolite gene clusters predicted in A. flavus, we examined their expression over 28 diverse conditions. Variables included culture medium and temperature, fungal development, colonization of developing maize seeds and misexpression of laeA, a global regulator of secondary metabolism. Hierarchical clustering analysis of expression profiles allowed us to categorize the gene clusters into four distinct clades. Gene clusters for the production of aflatoxins, CPA and seven other unknown compound(s) were identified as belonging to one clade. To further explore the relationships found by gene expression analysis, aflatoxin and CPA production were quantified under five different cell culture environments known to be conducive or nonconducive for aflatoxin biosynthesis and during the colonization of developing maize seeds. Results from these studies showed that secondary metabolism gene clusters have distinctive gene expression profiles. Aflatoxin and CPA were found to have unique regulation, but are sufficiently similar that they would be expected to co‐occur in substrates colonized with A. flavus.
The impact of computerised physician order entry on prescribing practices in a cardiothoracic intensive care unit*
Authors: Ali J. , Barrow L. , Vuylsteke A.
Published: November 2009

This prospective, time series, cross‐sectional study was designed to compare the quality of handwritten vs computerised prescriptions in a tertiary 25‐bedded cardiothoracic intensive care unit. A total of 14 721 prescriptions for 613 patients were analysed over three periods of investigation: 7 months before; and 5 and 12 months after implementation of a clinical information system with computerised physician order entry capability. Errors in prescribing were common. Only (53%) of handwritten charts analysed had all immediate administration drugs prescribed correctly. Errors included omission of route 81 (8.0%), date of prescription 78 (7.7%), and time to be given 255 (25.2%), and 119 (11.7%) had no dose or an incorrect dose prescribed. All errors of completeness were abolished following implementation. The computerised system led to a significant improvement in prescribing safety, in a clinical area previously highlighted as having a high rate of adverse drug errors. Legibility, completeness and traceability are no longer possible sources of medication errors.
Role of the interaction between Lu/BCAM and the spectrin‐based membrane skeleton in the increased adhesion of hereditary spherocytosis red cells to laminin
Authors: Gauthier Emilie , El Nemer Wassim , Wautier Marie P. , Renaud Olivier , Tchernia Gil , Delaunay Jean , Le Van Kim Caroline , Colin Yves
Published: November 2009

Lu/BCAM, the unique erythroid receptor for laminin 511/521, interacts with the erythrocyte membrane skeleton through spectrin binding. It has been reported that Hereditary Spherocytosis red blood cells (HS RBC) exhibit increased adhesion to laminin. We investigated the role of Lu/BCAM–spectrin interaction in the RBC adhesion properties of 2 splenectomised HS patients characterized by 40% spectrin deficiency. Under physiological flow conditions, HS RBC exhibited an exaggerated adhesion to laminin that was completely abolished by soluble Lu/BCAM. Triton extraction experiments revealed that a greater fraction of Lu/BCAM was unlinked to the membrane skeleton of HS RBC, as compared to normal RBC. Disruption of the spectrin interaction site in Lu/BCAM expressed in the transfected K562 cell line resulted in a weakened interaction to the skeleton and an enhanced interaction to laminin. These results demonstrated that the adhesion of HS RBC to laminin was mediated by Lu/BCAM and that its interaction with the spectrin‐based skeleton negatively regulated cell adhesion to laminin. Finally, the results of this study strongly suggest that the reinforced adhesiveness of spectrin‐deficient HS RBC to laminin is partly brought about by an impaired interaction between Lu/BCAM and the membrane skeleton.
Effect of adhesive system type and root region on the push‐out bond strength of glass–fibre posts to radicular dentine
Authors: Onay E. O. , Korkmaz Y. , Kiremitci A.
Published: November 2009

Onay EO, Korkmaz Y, Kiremitci A. Effect of adhesive system type and root region on the push‐out bond strength of glass–fibre posts to radicular dentine. International Endodontic Journal, 43, 76–85, 2010.

Aim  To compare interfacial strength in different thirds of the root canal amongst glass–fibre posts luted with four different adhesive luting agents.

Methodology  A total of 44 extracted human single‐rooted teeth were randomly divided in four groups and restored using glass–fibre posts and the following luting agents: All Bond SE/Duo‐Link (ABSE), All Bond 3/Duo‐Link (AB3), BisCem (BC), Clearfil ED primer II/Clearfil Esthetic Cement (CLF). One week after luting, the samples were thermocycled in water, and then embedded in acrylic resin. Three sections (cervical, middle and apical) of 2 mm thickness were prepared from each specimen, and the post in each section was subjected to a push‐out test. One additional specimen for each group was prepared for scanning electron microscopy analysis and the bonding effectiveness to dentine was assessed. The data were analysed using the Kolmogorov–Smirnov test, two‐way anova, one‐way anova, and the Scheffe test (P < 0.05).

Results  The push‐out bond strength values for BC and ABSE were not significantly different (P > 0.05), but both were significantly higher than the means for AB3 and CLF (P < 0.05) in the cervical and middle regions. The same trend was observed in the apical region, except for the AB3 and ABSE which were not significantly different (P > 0.05) from each other. There were significant differences in bond strength amongst root thirds, with a reduction in values from the cervical to apical third (P < 0.05).

Conclusions  The use of BisCem and All Bond SE/Duo‐Link combination with their simplified application procedures may be considered an alternative to the currently used systems for luting glass–fibre posts in root canal.
Growth of N2‐fixing African savanna Acacia species is constrained by below‐ground competition with grass
Authors: Cramer Michael D. , Van Cauter An , Bond William J.
Published: November 2009

1. The coexistence of leguminous trees and C4 grasses in many African savannas forces competition between these two distinct plant life‐forms. The nature of tree–grass coexistence and the consequent competition for resources remains poorly understood.

2. We hypothesized that grass suppression of tree seedling growth was due to competition for N in plants not capable of fixing N2 and due to the costs of N2 fixation in those capable of nodulation.

3. Growth and N2 fixation of nodulating (Acacia karroo, Acacia nilotica, Acacia tortilis and Acacia nigrescens) and non‐nodulating (Acacia ataxacantha Acacia brevispica and Acacia schweinfurthii) Acacia spp. in response to soil characteristics and fertilizer variations in irrigated field experiments were compared. The extent of N2 fixation was determined from δ15N values.

4. Grass suppressed the growth of all species, but particularly of the non‐nodulating species. The N2‐fixing tree seedlings had high tissue N and high water‐use efficiencies (WUE, based on δ13C) relative to non‐nodulating legumes, making the N2‐fixing species strong competitors with C4 grasses, which have low tissue N contents and high WUE. The suppression of seedling growth by grass was smaller for plants grown in a soil with 66 mg kg−1 than in a soil with 9 mg kg−1 of Bray II P. The tissue N : P ratios (15.1) indicated that P‐limitation constrained growth of seedlings in soils with low Bray II P when grass was present, rather than the energetic costs of N2 fixation.

5.
Synthesis. In Acacia savannas and in the absence of water limitation, competition for N is the main constraint imposed by grass on growth of Acacia seedlings and that the ability to fix N2 overcomes this limitation. However, the growth of N2 fixing Acacias may be additionally limited by grass competition for P.