bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency-dependent selection maintains clonal diversity in an asexual organism
Authors: Weeks Andrew R. , Hoffmann Ary A.
Published: November 2008

Asexual organisms can be genetically variable and evolve through time, yet it is not known how genetic diversity is maintained in populations. In sexual organisms, negative frequency-dependent selection plays a role in maintaining diversity at some loci, but in asexual organisms, this mechanism could provide a general explanation for persistent genetic diversity because it acts on the whole genome and not just on some polymorphisms within a genome. Using field manipulations, we show that negative frequency-dependent selection maintains clonal diversity in an asexual mite species, and we link predicted equilibrium clonal frequencies to average frequencies in space and time. Intense frequency-dependent selection is likely to be a general mechanism for persistent genetic diversity in asexual organisms.
Orbitofrontal cortex neurons as a common target for classic and glutamatergic antipsychotic drugs
Authors: Homayoun Houman , Moghaddam Bita
Published: November 2008

Until recently, all known antipsychotic drugs were thought to block the dopamine D2 receptor. New evidence that agonists of the metabotropic glutamate 2/3 (mGlu2/3) receptors ameliorate psychotic and affective symptoms of schizophrenia suggests that compounds with different molecular targets may act on a common cellular target to treat schizophrenia. We hypothesized that normalizing the activity of neurons in the orbitofrontal cortex (OFC), a region that is increasingly implicated in the pathophysiology of schizophrenia, presents such a target. We disrupted OFC activity in behaving rats with a use-dependent NMDA antagonist to model the NMDA hypofunction state that may occur in schizophrenia. This systemic treatment increased the activity of most pyramidal cells while inhibiting the activity of putative inhibitory GABA interneurons and increasing behavioral stereotypy. A similar pattern of OFC firing disruption was observed after amphetamine, which models a dopamine hyperactivity state in schizophrenia and which produces a pattern of firing disruption different from those of NMDA antagonists in other prefrontal cortex regions. Antipsychotic drugs haloperidol and clozapine, which target monoamine receptors, as well as an mGlu2/3 agonist and an mGlu5 receptor modulator proposed to have antipsychotic efficacy, reversed the impact of NMDA hypofunction on OFC cells and on behavior. A similar pattern of normalization of OFC activity was observed when treatments were given after amphetamine. Thus, proven or putative antipsychotic drugs with different mechanisms of action similarly reduced the impact of NMDA hypofunction and dopamine hyperfunction on OFC neurons, suggesting that these neurons are a candidate target for the therapeutic effects of antipsychotic medications.
Structure of influenza hemagglutinin in complex with an inhibitor of membrane fusion
Authors: Russell Rupert J. , Kerry Philip S. , Stevens David J. , Steinhauer David A. , Martin Stephen R. , Gamblin Steven J. , Skehel John J.
Published: November 2008

The influenza surface glycoprotein hemagglutinin (HA) is a potential target for antiviral drugs because of its key roles in the initial stages of infection: receptor binding and the fusion of virus and cell membranes. The structure of HA in complex with a known inhibitor of membrane fusion and virus infectivity,
tert
-butyl hydroquinone (TBHQ), shows that the inhibitor binds in a hydrophobic pocket formed at an interface between HA monomers. Occupation of this site by TBHQ stabilizes the neutral pH structure through intersubunit and intrasubunit interactions that presumably inhibit the conformational rearrangements required for membrane fusion. The nature of the binding site suggests routes for the chemical modification of TBHQ that could lead to the development of more potent inhibitors of membrane fusion and potential anti-influenza drugs.
Mediator-assisted water oxidation by the ruthenium “blue dimer”cis,cis-[(bpy)2(H2O)RuORu(OH2)(bpy)2]4+
Authors: Concepcion Javier J. , Jurss Jonah W. , Templeton Joseph L. , Meyer Thomas J.
Published: November 2008

Light-driven water oxidation occurs in oxygenic photosynthesis in photosystem II and provides redox equivalents directed to photosystem I, in which carbon dioxide is reduced. Water oxidation is also essential in artificial photosynthesis and solar fuel-forming reactions, such as water splitting into hydrogen and oxygen (2 H2O + 4 hν → O2+ 2 H2) or water reduction of CO2to methanol (2 H2O + CO2+ 6 hν → CH3OH + 3/2 O2), or hydrocarbons, which could provide clean, renewable energy. The “blue ruthenium dimer,”cis,cis-[(bpy)2(H2O)RuIIIORuIII(OH2)(bpy)2]4+, was the first well characterized molecule to catalyze water oxidation. On the basis of recent insight into the mechanism, we have devised a strategy for enhancing catalytic rates by using kinetically facile electron-transfer mediators. Rate enhancements by factors of up to ≈30 have been obtained, and preliminary electrochemical experiments have demonstrated that mediator-assisted electrocatalytic water oxidation is also attainable.
Reproductive constraint is a developmental mechanism that maintains social harmony in advanced ant societies
Authors: Khila Abderrahman , Abouheif Ehab
Published: November 2008

A hallmark of eusociality in ants is the reproductive division of labor between queens and workers. Yet, nothing is known about the molecular mechanisms underlying reproduction in this group. We therefore compared the developmental genetic capacity of queens and workers to reproduce in several eusocially advanced species from the two largest subfamilies of ants, the Myrmicinae and Formicinae. In flies, the asymmetric localization of maternally encoded determinants (mRNAs and proteins) during oogenesis establishes oocyte polarity and subsequently ensures proper embryonic development. Vasa and
nanos
, two key maternal determinants, are properly localized in the posterior of queen oocytes, but their localization is impaired in those of the workers. This mislocalization leads to severe embryonic defects in worker progeny, and therefore, represents a constraint on worker reproduction that we call ‘reproductive constraint.’ We show that reproductive constraint is phylogenetically widespread, and is at high levels in most species tested. Reproductive constraint can simultaneously reduce or eliminate the workers' ability to produce viable eggs for reproduction, while preserving their ability to produce trophic eggs for nutrition, and thus, may have been the basis for the evolutionary retention of worker ovaries in the majority of ants. We propose that high levels of reproductive constraint has most likely evolved as a consequence of selection at the colony level to reduce or eliminate any potential conflict over worker reproduction, therefore maintaining harmony and colony efficiency in advanced ant societies.
Lipoarabinomannan of
Mycobacterium
: Mannose capping by a multifunctional terminal mannosyltransferase
Authors: Kaur Devinder , Obregón-Henao Andrés , Pham Ha , Chatterjee Delphi , Brennan Patrick J. , Jackson Mary
Published: November 2008

Biosynthesis of phosphatidylinositol (PI)-containing lipoarabinomannan (LAM) and lipomannan (LM) of
Mycobacterium
spp. follows a conserved pathway involving multiple membrane-associated, substrate-specific mannosyltransferases (ManTs) responsible for the sequential addition of α-mannopyranosyl (Man
p
) units donated by decaprenyl-P-Man
p
on the periplasmic side of the plasma membrane. Because of their receptor-binding and immunomodulatory properties, the α(1→2)-linked di- and tri-Man
p
motifs that functionalize the nonreducing arabinan termini of LAM (ManLAM) in
Mycobacterium tuberculosis
are of crucial importance. We now show that the
M. tuberculosis
ManT, Rv2181, is required for the addition of these α(1→2)-linked Man
p
residues but also at other locations of the LAM molecule. Structural analyses of the LM and LAM variants produced by a
M. tuberculosis Rv2181
knockout mutant revealed the presence of but a single Man
p
residue on the nonreducing arabinan termini of LAM and also a complete absence of α(1→2)-linked Man branching on the mannan backbones of LM and LAM. A recombinant strain was constructed in ManLAM-deficient
Mycobacterium smegmatis
that coexpressed
Rv2181
and
Rv1635c
—the ManT responsible for the addition of the first Man
p
capping residue of ManLAM. Analysis revealed LAM termini fully capped with di- and tri-Man
p
motifs in addition to α(1→2)Man branching on the mannan backbones of LM and LAM, confirming the involvement of the α(1→2)ManT Rv2181 in the dual role of Man capping and mannan-core branching, and in the process generated a rapidly growing, ManLAM-containing strain, a tool for the study of the role of ManLAM in the pathogenesis of tuberculosis.
The influence of sex, handedness, and washing on the diversity of hand surface bacteria
Authors: Fierer Noah , Hamady Micah , Lauber Christian L. , Knight Rob
Published: November 2008

Bacteria thrive on and within the human body. One of the largest human-associated microbial habitats is the skin surface, which harbors large numbers of bacteria that can have important effects on health. We examined the palmar surfaces of the dominant and nondominant hands of 51 healthy young adult volunteers to characterize bacterial diversity on hands and to assess its variability within and between individuals. We used a novel pyrosequencing-based method that allowed us to survey hand surface bacterial communities at an unprecedented level of detail. The diversity of skin-associated bacterial communities was surprisingly high; a typical hand surface harbored >150 unique species-level bacterial phylotypes, and we identified a total of 4,742 unique phylotypes across all of the hands examined. Although there was a core set of bacterial taxa commonly found on the palm surface, we observed pronounced intra- and interpersonal variation in bacterial community composition: hands from the same individual shared only 17% of their phylotypes, with different individuals sharing only 13%. Women had significantly higher diversity than men, and community composition was significantly affected by handedness, time since last hand washing, and an individual's sex. The variation within and between individuals in microbial ecology illustrated by this study emphasizes the challenges inherent in defining what constitutes a “healthy” bacterial community; addressing these challenges will be critical for the International Human Microbiome Project.
Differential degradation of PIN2 auxin efflux carrier by retromer-dependent vacuolar targeting
Authors: Kleine-Vehn Jürgen , Leitner Johannes , Zwiewka Marta , Sauer Michael , Abas Lindy , Luschnig Christian , Friml Jiří
Published: November 2008

All eukaryotic cells present at the cell surface a specific set of plasma membrane proteins that modulate responses to internal and external cues and whose activity is also regulated by protein degradation. We characterized the lytic vacuole-dependent degradation of membrane proteins in
Arabidopsis thaliana
by means of in vivo visualization of vacuolar targeting combined with quantitative protein analysis. We show that the vacuolar targeting pathway is used by multiple cargos including PIN-FORMED (PIN) efflux carriers for the phytohormone auxin. In vivo visualization of PIN2 vacuolar targeting revealed its differential degradation in response to environmental signals, such as gravity. In contrast to polar PIN delivery to the basal plasma membrane, which depends on the vesicle trafficking regulator ARF-GEF GNOM, PIN sorting to the lytic vacuolar pathway requires additional brefeldin A-sensitive ARF-GEF activity. Furthermore, we identified putative retromer components SORTING NEXIN1 (SNX1) and VACUOLAR PROTEIN SORTING29 (VPS29) as important factors in this pathway and propose that the retromer complex acts to retrieve PIN proteins from a late/pre-vacuolar compartment back to the recycling pathways. Our data suggest that ARF GEF- and retromer-dependent processes regulate PIN sorting to the vacuole in an antagonistic manner and illustrate instrumentalization of this mechanism for fine-tuning the auxin fluxes during gravitropic response.
Environmental and anthropogenic controls over bacterial communities in wetland soils
Authors: Hartman Wyatt H. , Richardson Curtis J. , Vilgalys Rytas , Bruland Gregory L.
Published: November 2008

Soil bacteria regulate wetland biogeochemical processes, yet little is known about controls over their distribution and abundance. Bacteria in North Carolina swamps and bogs differ greatly from Florida Everglades fens, where communities studied were unexpectedly similar along a nutrient enrichment gradient. Bacterial composition and diversity corresponded strongly with soil pH, land use, and restoration status, but less to nutrient concentrations, and not with wetland type or soil carbon. Surprisingly, wetland restoration decreased bacterial diversity, a response opposite to that in terrestrial ecosystems. Community level patterns were underlain by responses of a few taxa, especially the
Acidobacteria
and
Proteobacteria
, suggesting promise for bacterial indicators of restoration and trophic status.
Real-time luminescence monitoring of cell-cycle and respiratory oscillations in yeast
Authors: Robertson J. Brian , Stowers Chris C. , Boczko Erik , Hirschie Johnson Carl
Published: November 2008

The use of luciferase reporters has become a precise, noninvasive, high-throughput method for real-time monitoring of promoter activity in living cells, especially for rhythmic biological processes such as circadian rhythms. We developed a destabilized firefly luciferase as a reporter for rhythmic promoter activity in both the cell division and respiratory cycles of the budding yeast
Saccharomyces cerevisiae
in which real-time luminescence reporters have not been previously applied. The continuous output of light from luciferase reporters allowed us to explore the relationship between the cell division cycle and the yeast respiratory oscillation, including the observation of responses to chemicals that cause phase shifting of the respiratory oscillations. Destabilized firefly luciferase is a good reporter of cell cycle position in synchronized or partially synchronized yeast cultures, in both batch and continuous cultures. In addition, the oxygen dependence of luciferase can be used under certain conditions as a genetically encodable oxygen monitor. Finally, we use this reporter to show that there is a direct correlation between premature induction of cell division and phase resetting of the respiratory oscillation under the continuous culture conditions tested.
Annotating proteins with generalized functional linkages
Authors: Llewellyn Richard , Eisenberg David S.
Published: November 2008

As genome sequencing outstrips the rate of high-quality, low-throughput biochemical and genetic experimentation, accurate annotation of protein function becomes a bottleneck in the progress of the biomolecular sciences. Most gene products are now annotated by homology, in which an experimentally determined function is applied to a similar sequence. This procedure becomes error-prone between more divergent sequences and can contaminate biomolecular databases. Here, we propose a computational method of assignment of function, termed Generalized Functional Linkages (GFL), that combines nonhomology-based methods with other types of data. Functional linkages describe pairwise relationships between proteins that work together to perform a biological task. GFL provides a Bayesian framework that improves annotation by arbitrating a competition among biological process annotations to best describe the target protein. GFL addresses the unequal strengths of functional linkages among proteins, the quality of existing annotations, and the similarity among them while incorporating available knowledge about the cellular location or individual molecular function of the target protein. We demonstrate GFL with functional linkages defined by an algorithm known as zorch that quantifies connectivity in protein–protein interaction networks. Even when using proteins linked only by indirect or high-throughput interactions, GFL predicts the biological processes of many proteins in
Saccharomyces cerevisiae
, improving the accuracy of annotation by 20% over majority voting.
Probing synaptic vesicle fusion by altering mechanical properties of the neuronal surface membrane
Authors: Zhu Yongling , Stevens Charles F.
Published: November 2008

Because synaptic vesicle exocytosis is a nano-mechanical process, it should be influenced by the mechanical properties of the cell membrane to which the vesicle fuses. By dissolving surfactants at various concentrations in the neuronal membrane, we have perturbed mechanical properties of the membrane and have found that dissolved surfactants lower the probability that a synaptic vesicle will open its fusion pore when the fusion machinery of the vesicle is activated by binding calcium. By using standard theories from the physics and chemistry of surfaces, we can account for this decrease in fusion probability and can infer that a vesicle, when activated, opens its fusion pore ≈3 times out of 4 and that the area of the fusion pore is ≈4 nm
2
.
Subtracting difference: Troubling transitions from GCSE to AS‐level mathematics
Authors: Mendick Heather
Published: November 2008

This article provides an approach to understanding the widely acknowledged difficulties experienced by young people in the transition from pre‐16 to post‐16 mathematics. Most approaches to understanding the disenchantment with and drop‐out from AS‐level mathematics focus on curriculum and assessment. In contrast, this article looks at the role of relationships, taking a psychosocial approach. It draws on data from a three‐year qualitative study into why young people choose mathematics. It argues that educational practitioners and policy makers are responding to stories of failure and drop‐out by excluding more people from access to mathematics. There is less and less room for difference within our mathematics classrooms. This happens because of the ways that discourses around mathematics fix how we think of the subject, who can learn it and what kind of relationships are possible between learners and mathematics. Instead the article argues for unfixing these through policies and pedagogies of difference.
Phosphorylation of a Novel Site on the β4 Integrin at the Trailing Edge of Migrating Cells Promotes Hemidesmosome Disassembly
Authors: Germain Emily C. , Santos Tanya M. , Rabinovitz Isaac
Published: November 2008

Hemidesmosomes (HDs) are multiprotein structures that anchor epithelial cells to the basement membrane. HD components include the α6β4 integrin, plectin, and BPAGs (bullous pemphigoid antigens). HD disassembly in keratinocytes is necessary for cells to migrate and can be induced by EGF through β4 integrin phosphorylation. We have identified a novel phosphorylation site on the β4 integrin: S1424. Preventing phosphorylation by mutating S→A1424results in increased incorporation of β4 into HDs and resistance to EGF-induced disassembly. In contrast, mutating S→D1424(mimicking phosphorylation) partially mobilizes β4 from HDs and potentiates the disassembly effects of other phosphorylation sites. In contrast to previously described sites that are phosphorylated upon growth factor stimulation, S1424already exhibits high constitutive phosphorylation, suggesting additional functions. Constitutive phosphorylation of S1424is distinctively enriched at the trailing edge of migrating keratinocytes where HDs are disassembled. Although most of this S1424-phosphorylated β4 is found dissociated from HDs, a substantial amount can be associated with HDs near the cell margins, colocalizing with plectin but always excluding BPAGs, suggesting that phospho-S1424might be a mechanism to dissociate β4 from BPAGs. S1424phosphorylation is PKC dependent. These data suggest an important role for S1424in the gradual disassembly of HDs induced by cell retraction.
Cells Lacking the Fragile X Mental Retardation Protein (FMRP) have Normal RISC Activity but Exhibit Altered Stress Granule Assembly
Authors: Didiot Marie-Cécile , Subramanian Murugan , Flatter Eric , Mandel Jean-Louis , Moine Hervé
Published: November 2008

The fragile X mental retardation protein (FMRP) is an RNA-binding protein involved in the mRNA metabolism. The absence of FMRP in neurons leads to alterations of the synaptic plasticity, probably as a result of translation regulation defects. The exact molecular mechanisms by which FMRP plays a role in translation regulation have remained elusive. The finding of an interaction between FMRP and the RNA interference silencing complex (RISC), a master of translation regulation, has suggested that both regulators could be functionally linked. We investigated here this link, and we show that FMRP exhibits little overlap both physically and functionally with the RISC machinery, excluding a direct impact of FMRP on RISC function. Our data indicate that FMRP and RISC are associated to distinct pools of mRNAs. FMRP, unlike RISC machinery, associates with the pool of mRNAs that eventually goes into stress granules upon cellular stress. Furthermore, we show that FMRP plays a positive role in this process as the lack of FMRP or a point mutant causing a severe fragile X alter stress granule formation. Our data support the proposal that FMRP plays a role in controlling the fate of mRNAs after translation arrest.
A Myopathy-linked Desmin Mutation Perturbs Striated Muscle Actin Filament Architecture
Authors: Conover Gloria M. , Henderson Syerra N. , Gregorio Carol C.
Published: November 2008

Desmin interacts with nebulin establishing a direct link between the intermediate filament network and sarcomeres at the Z-discs. Here, we examined a desmin mutation, E245D, that is located within the coil IB (nebulin-binding) region of desmin and that has been reported to cause human cardiomyopathy and skeletal muscle atrophy. We show that the coil IB region of desmin binds to C-terminal nebulin (modules 160-164) with high affinity, whereas binding of this desmin region containing the E245D mutation appears to enhance its interaction with nebulin in solid-phase binding assays. Expression of the desmin-E245D mutant in myocytes displaces endogenous desmin and C-terminal nebulin from the Z-discs with a concomitant increase in the formation of intracellular aggregates, reminiscent of a major histological hallmark of desmin-related myopathies. Actin filament architecture was strikingly perturbed in myocytes expressing the desmin-E245D mutant because most sarcomeres contained elongated or shorter actin filaments. Our findings reveal a novel role for desmin intermediate filaments in modulating actin filament lengths and organization. Collectively, these data suggest that the desmin E245D mutation interferes with the ability of nebulin to precisely regulate thin filament lengths, providing new insights into the potential molecular consequences of expression of certain disease-associated desmin mutations.
Coiled-Coil–Mediated Dimerization Is Not Required for Myosin VI to Stabilize Actin during Spermatid Individualization inDrosophila melanogaster
Authors: Noguchi Tatsuhiko , Frank Deborah J. , Isaji Mamiko , Miller Kathryn G.
Published: November 2008

Myosin VI is a pointed-end–directed actin motor that is thought to function as both a transporter of cargoes and an anchor, capable of binding cellular components to actin for long periods. Dimerization via a predicted coiled coil was hypothesized to regulate activity and motor properties. However, the importance of the coiled-coil sequence has not been tested in vivo. We used myosin VI's well-defined role in actin stabilization during Drosophila spermatid individualization to test the importance in vivo of the predicted coiled coil. If myosin VI functions as a dimer, a forced dimer should fully rescue myosin VI loss of function defects, including actin stabilization, actin cone movement, and cytoplasmic exclusion by the cones. Conversely, a molecule lacking the coiled coil should not rescue at all. Surprisingly, neither prediction was correct, because each rescued partially and the molecule lacking the coiled coil functioned better than the forced dimer. In extracts, no cross-linking into higher molecular weight forms indicative of dimerization was observed. In addition, a sequence required for altering nucleotide kinetics to make myosin VI dimers processive is not required for myosin VI's actin stabilization function. We conclude that myosin VI does not need to dimerize via the predicted coiled coil to stabilize actin in vivo.
Understanding Consumer Preference for Functional Barley Tortillas Through Sensory, Demographic, and Behavioral Data
Authors: Toma Ayako , Omary María Botero , Rosentrater Kurt A. , Arndt Elizabeth A. , Prasopsunwattana Naruemon , Chongcham Sutida , Flores Rolando A. , Lee Sylvia P.
Published: November 2008

Consumption of whole grains as part of a health‐promoting diet is encouraged among Americans due to beneficial nutrients and phytochemicals. The main objectives of this study were to investigate the effect of whole barley flour particle size on consumer acceptance of whole grain and soluble fiber‐enriched tortillas; to examine the effect of demographic and behavioral data on consumer acceptance; and to establish relationships between consumer acceptance and survey results to identify market opportunities among particular groups of consumers. Four experimental tortillas and two representative commercial brands were tested by 95 untrained panelists using a 9‐point hedonic scale for appearance, color, flavor, texture, and overall acceptability. Demographic and behavioral data on age, gender, ethnicity, frequency of tortilla consumption, daily effort to include fiber in the diet, consumption of tortillas containing ≥1 g of dietary fiber/serving, consumption of low‐fat tortillas, and tortilla brands and type used were collected. Potential market segments for these tortillas include older consumers (41+), women, Hispanics, and Asians, and frequent tortilla consumers. A response surface relating flavor and texture to overall acceptability produced almost equivalent results to the multivariate PLS results in terms of predicting overall acceptability, which facilitates analysis and interpretation.
Commercial Evaluation of a Continuous Micronutrient Fortification Process for Nixtamal Tortillas
Authors: Dunn Michael L. , Serna‐Saldivar Sergio O. , Sanchez‐Hernandez Diana , Griffin Robert W.
Published: November 2008

The corn tortilla plays an integral role in the Mexican diet and is an ideal vehicle for micronutrient fortification. Approximately 60% of corn tortillas in Mexico are produced from nixtamal, with the remainder prepared from masa flour. A process for continuous fortification of nixtamal tortillas was evaluated in two commercial mills in Mexico. A commercial powder dosifier was used to add micronutrient premix containing iron, zinc, folic acid, niacin, riboflavin, and thiamin to nixtamal (1 g/kg) as it was milled. After training and preliminary sampling, mills produced fortified tortillas unassisted for four weeks. Masa flow rates over a four‐day period were 10–12 kg/min in both plants. Premix flow from the dosifier showed good stability, with an average coefficient of variation of 1.6%. Initial results indicated consistency in the fortification process, with significantly increased variation during the four‐week production period. Fortified tortillas had significantly higher levels of all nutrients tested. Micronutrient losses were <11% in all cases except folic acid, which showed an 80% loss. Despite processing losses, fortification resulted in a nearly fivefold increase in folic acid compared with control tortillas. The new fortification process is technically viable and was well received by millers.
Rheological Properties of Wheat Flour Dough and the Relationship with Bread Volume. I. Creep‐Recovery Measurements
Authors: Van Bockstaele Filip , De Leyn Ingrid , Eeckhout Mia , Dewettinck Koen
Published: November 2008

The rheological properties of 17 pure European wheat cultivars were analyzed and evaluated in relation to the bread volume. Rheological testing included two empirical rheological methods, farinograph and alveograph, and more fundamental creep‐recovery experiments at shear stresses of 100 and 250 Pa. Principal component analysis on the farinograph and alveograph results showed that a wide range of rheological properties was present among the wheat cultivars. Correlation analysis pointed out that creep‐recovery parameters showed significant correlations with protein content, Zeleny sedimentation value, farinograph water absorption, alveograph extensibility, and bread volume. Among the rheological parameters, maximum recovery strain at a shear stress of 250 Pa showed the highest significant correlation with the bread volume (r = 0.790**). Variables were combined to predict the bread volume by multiple linear regression. A combination of protein content, farinograph water absorption, and alveograph P/L showed the best prediction (r2 = 0.80). When taking into account the creep‐recovery parameters, the best prediction of the bread volume (r2 = 0.74) was obtained for a combination of the maximum recovery strain at a shear stress of 250 Pa with one other quality parameter (Zeleny sedimentation value, farinograph water absorption, or alveograph W).
Resistance to Root Galling Caused by the Powdery Scab Pathogen Spongospora subterranea in Potato
Authors: Nitzan Nadav , Cummings Tom F. , Johnson Dennis A. , Miller Jeff S. , Batchelor Dallas L. , Olsen Chris , Quick Richard A. , Brown Charles R.
Published: November 2008

Potato (Solanum tuberosum) selections (clones and commercial cultivars) were examined for resistance to root galling, caused by the powdery scab pathogen Spongospora subterranea f. sp. subterranea in seven field trials conducted between 2003 and 2007 in the states of Washington and Idaho. Four industry reference cultivars—Shepody, Russet Burbank, Russet Ranger, and Umatilla Russet—were used as susceptible standards. Every year, selections less susceptible than the standards were considered resistant and progressed to the next season. Selections that did not demonstrate resistance in at least two consecutive trials were discarded. Eight potato selections were more resistant to root galling than the susceptible standards in two or more trials: PA98NM38-1 was more resistant than the susceptible standards in 5 of 5 trials, PO94A009-10 in 4 of 5 trials, PA95B2-4 and PA98N5-2 in 3 of 5 trials, POR00HG5-1 in 2 of 5 trials, PO94A009-7 in 3 of 4 trials, PO94A012-2 in 2 of 3 trials, and Summit Russet in 2 of 2 trials. POR00HG5-1 has Solanum hougasii in its ancestry, while the other selections have the Mexican wild species Solanum bulbocastanum and the commercial cultivar Summit Russet appearing in their ancestry. Summit Russet is the most plausible source of resistance.
First Report of Rosa multiflora cryptic virus in Rosa multiflora in the Eastern United States
Authors: Martin R. R. , Tzanetakis I. E.
Published: November 2008

In the process of attempting to identify the rose rosette agent, double-stranded RNA was isolated from several symptomatic Rosa multiflora plants from northwestern Arkansas. The pattern of the dsRNA bands differed among the five samples used in this study, suggesting the presence of several viruses. Four of the five plants tested had two predominant bands of approximately 1.8 and 1.5 kbp, a pattern similar to that observed in plants infected with Fragaria chiloensis cryptic virus (FCCV; 3), and further steps were taken for the identification of the putative virus. One plant that only had the two predominant bands was chosen for further characterization using degenerate oligonucleotide primed (DOP)-PCR (4). Twenty clones were sequenced and all were found to be part of two contigs of 937 and 1,087 nucleotides that have been deposited in GenBank (Accession nos. EU350962 and EU350963). The two contigs had 82 and 72% nucleotide and 85 and 69% amino acid sequence identities with RNA 1 and 2 of FCCV, respectively; 98 and 99% amino acid sequence identities with Rose multiflora cryptic virus (RMCV; 2) RNA 1 and 3, respectively. Oligonucleotide primers F (5′ gaatgggaactacgctttgc 3′) and R (5′ cgatgcttccaatgatgttg 3′) designed to amplify a 196-bp region of RNA 1 of the virus were tested using ss and dsRNA templates and were shown to be virus specific after sequencing of multiple PCR amplicons. Just before submission of this manuscript, the complete sequence of RMCV, a virus isolated from R. multiflora showing rose spring dwarf symptoms was published (2). RMCV and the dsRNAs isolated from R. multiflora in Arkansas are the same species because they share 99% nucleotide sequence identity. Cryptic viruses are expected to be symptomless though mild symptoms have been associated with several cryptic viruses (1). The presence of RMCV has been verified in both symptomless and plants infected with two severe diseases of rose, thus, the virus could play a role in the phenotype of these diseases as part of a virus complex. To our knowledge, this is the first report of RMCV in the eastern United States, which is closley related to RMCV from California (2). In the review process of this note, it was brought to our attention that a similar virus named Rose cryptic virus 1 was being investigated in Mississippi (Genbank Accession Nos. EU413666–68), supporting the statement that this virus is probably widespread in Rosa germplasm.

References: (1) L. Chen et al. Arch. Virol. 151:849, 2006. (2) N. M. Salem et al. Arch. Virol. 153:455, 2008. (3) I. E. Tzanetakis et al. Virus Genes 36:267, 2008. (4) I. E. Tzanetakis and R. R. Martin. J. Virol. Methods 149:167, 2008.
First Report of Stem Blight Caused by Botrytis cinerea on Jasminum officinalis in Italy
Authors: Aiello D. , Parlavecchio G. , Vitale A. , Polizzi G.
Published: November 2008

Common jasmine (Jasminum officinalis L.) is an evergreen shrub that is native to the Middle and Far East. It is widely grown in Europe as an ornamental plant and in southeastern France for fragrance for the perfume industry. In March of 2008, a previously undescribed disease was observed on potted (6-month- to 3-year-old) common jasmine plants growing in open fields in a nursery of eastern Sicily, Italy. More than 20% of the plants showed disease symptoms. Diseased plants had small to large, brown or black lesions on stem. The lesions expanded rapidly, girdled the stem and caused blight of entire branches, and occasionally killed the plant. Abundant conidia and mycelia were detected on the surface of dead and dying stems under cool and humid conditions, which resulted in a moldy gray appearance. Botrytis cinerea Pers.:Fr. (1) was consistently isolated from affected tissues disinfected for 1 min in 1% NaOCl, rinsed in sterile water, and plated on potato dextrose agar (PDA). Colonies were at first white then became gray after 6 to 7 days when spores differentiated. White sclerotia developed after 8 to 9 days and turned black with age. Size of the conidia produced on 1-month-old culture ranged from 5.0 to 9.5 × 6.5 to 12.5 μm on the basis of 50 spore measurements. Sclerotia were spherical or irregular and ranged from 1.0 to 2.5 × 0.9 to 2.9 mm (average 1.7 × 1.8 mm). Stems of eight 6-month-old common jasmine plants were lightly wounded with a sterile razor and inoculated with 3-mm-diameter plugs of PDA from 10-day-old mycelial cultures, eight similar plants were inoculated with mycelium without wounding, and an equal number of noninoculated plants inoculated with only PDA plugs served as control. After inoculation, plants were enclosed in transparent plastic bags at 20 ± 2°C for 5 days. Stem lesions identical to the ones observed in the nursery were detected on all wounded and on two nonwounded fungus-inoculated plants within 5 to 7 days. Control plants remained healthy. B. cinerea was reisolated from typical lesions. The unusually cool and humid weather conditions recorded in Sicily are supposed to be highly conducive of disease outbreak. Although B. cinerea does not usually kill the plants, under these environmental conditions this disease can cause significant economic loss to ornamental nurseries. To our knowledge, this is the first report of B. cinerea causing stem blight on J. officinalis.

Reference: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CAB, Kew, Surrey, England, 1971.
First Report of Tobacco ringspot virus in Blackberry (Rubus sp.) in Alabama
Authors: Coneva E. , Murphy J. F. , Boozer R. , Velásquez N.
Published: November 2008

In 2006, primocane stunted growth and crumbly berry development were observed on 4-year-old Kiowa and Apache blackberry cultivars grown at the Chilton Research and Extension Center, Clanton, AL. Samples from affected plants were tested for virus infection by ELISA kits (Agdia, Inc., Elkhart, IN) specific to each of 14 different viruses. Most samples tested positive for Tobacco ringspot virus (TRSV). TRSV was detected in blackberry samples from North Carolina and South Carolina (2). Bray et al. (1) studied the incidence of viruses in blackberry nursery stock in the United States and reported that 9% of the tested samples contained TRSV. Thus, a survey was conducted for TRSV incidence among commercial blackberry stands in eight counties in Alabama during July 2007. Blackberry plants were observed to express virus-like symptoms including chlorotic spots on leaves, leaf veinal chlorosis, stunting, and combinations thereof. Fruit-bearing plants sometimes had crumbly fruit symptoms characteristic of virus infection. Leaf samples that were collected from symptomatic and nonsymptomatic plants representing 14 cultivars were tested by TRSV ELISA (Agdia, Inc.). Of 180 blackberry samples, 68 tested positive for TRSV. Positive ELISA reactions for TRSV were on average 28 times greater than the reactions of known negative control samples considered negative for TRSV. Blackberry plants shown to be infected with TRSV during the 2007 survey were tested in July 2008 in an effort to confirm the presence of TRSV. Fifty-four percent of the samples tested positive by ELISA with the average positive ELISA value being 21 times higher than the average negative ELISA value for known negative control samples. To further confirm the occurrence of TRSV in Alabama-grown blackberry plants, leaf samples were tested by reverse transcription (RT)-PCR to amplify a 329-bp fragment of the viral coat protein gene (TRSV RNA 2 sequence accession no. NC_005096; primers TRSCP-F (5′-TCTGGCACTATAAGCGGAAG-3′) and TRSCP-R (5′-GAAAACATGGGAGGATGCAC-3′). A single band of the anticipated size was amplified (analyzed by agarose gel electorphoresis and visualized by ethidium bromide staining) from RNA samples extracted with a RNeasy Mini kit (Qiagen, Valencia, CA) from blackberry samples that tested positive for TRSV by ELISA and a known positive control. No amplified product resulted from a blackberry sample that tested negative for TRSV by ELISA. These results illustrate and confirm the presence of TRSV in blackberry leaf tissues grown in Alabama. To our knowledge, this is the first report of TRSV infection of blackberry plants in Alabama.

References: (1) M. M. Bray et al. HortScience 40:874, 2005. (2) T. L. Guzmán-Baeny. Incidence, distribution, and symptom description of viruses in cultivated blackberry (Rubus subgenus Eubatus) in the southeastern United States. M.S. thesis, North Carolina State University, Raleigh, 2003.
Signaling Pathways Involved in Desflurane-induced Postconditioning in Human Atrial Myocardium In Vitro
Authors: Lemoine Sandrine , Beauchef Gallic , Zhu Lan , Renard Emmanuelle , Lepage Olivier , Massetti Massimo , Khayat André , Galera Philippe , Gérard Jean-Louis , Hanouz Jean-Luc
Published: November 2008

Background

Isoflurane and sevoflurane have been shown to elicit myocardial postconditioning, but the effect of desflurane remain unknown. The authors studied the mechanisms involved in desflurane-induced myocardial postconditioning.

Methods

Contracting isolated human right atrial trabeculae (34 degrees C, stimulation frequency 1 Hz) were exposed to 30-min hypoxia followed by 60-min reoxygenation. Desflurane at 3%, 6%, and 9% was administered during the first 5-min of reoxygenation. Postconditioning with 6% desflurane was studied in the presence of 1 microM calphostin C, a protein kinase C inhibitor; 800 mm 5-hydroxydecanoate, a mitochondrial adenosine triphosphate-sensitive potassium channels antagonist; 1 microM Akt inhibitor; 20 microM PD89058, an extracellular-regulated kinase 1/2 inhibitor; and 1 microM SB 202190, a p38 mitogen-activated protein kinase inhibitor. The force of contraction at the end of the 60-min reoxygenation period was compared (mean +/- SD). The p38 mitogen-activated protein kinase phosphorylation was studied using Western blotting.

Results

Desflurane at 3% (77 +/- 10% of baseline), 6% (90 +/- 14% of baseline), and 9% (86 +/- 11% of baseline) enhanced the recovery of force after 60 min of reoxygenation as compared with the control group (51 +/- 9% of baseline; P < 0.001). Calphostin C (55 +/- 3% of baseline), 5-hydroxydecanoate (53 +/- 3% of baseline), Akt inhibitor (57 +/- 8% of baseline), PD89058 (64 +/- 6% of baseline), and SB 202190 (61 +/- 3% of baseline) abolished desflurane-induced postconditioning. Western blot analysis showed that 6% desflurane increased p38 mitogen-activated protein kinase phosphorylation.

Conclusions

In vitro, desflurane postconditioned human atrial myocardium through protein kinase C activation, opening of mitochondrial adenosine triphosphate-sensitive potassium channels, Akt and extracellular-regulated kinase 1/2 activation, and p38 mitogen-activated protein kinase phosphorylation.
How Much Does Pharmacologic Prophylaxis Reduce Postoperative Vomiting in Children?
Authors: Engelman Edgard , Salengros Jean-Corentin , Barvais Luc
Published: November 2008

Background

The authors calculated the effect size for treatments recommended for the pediatric population in the new Guidelines for the Management of Postoperative Nausea and Vomiting that should be implemented with the help of a new risk scale developed for children.

Methods

Six single-drug therapies and five combination treatments were subjected to a Bayesian analysis, with respect to the outcome reported, in a sequence that parallels their dates of publication. Based on the Bayes theorem, a posterior probability was calculated after inclusion of the data from the successive studies, to update a prior probability existing before inclusion of that study. The posterior for the preceding group of trials served as the prior for the subsequent trial. The final odds ratio with its 95% credibility interval compared with placebo is considered as the results for that treatment, and was transformed into a relative risk whose 95% credibility interval allows the calculation of a most pessimistic and a most optimistic incidence of postoperative vomiting.

Results

The most pessimistic expectations with the 5-hydroxytryptamine receptor antagonists and dexamethasone result in a 50-60% relative risk reduction. The results with droperidol offer a decrease of only approximately 40%. With the combinations of a 5-hydroxytryptamine receptor antagonist and dexamethasone, a relative risk reduction of approximately 80% is expected.

Conclusions

The authors' tables list the expected incidence of postoperative vomiting with each treatment for each risk category, and the expected relative risks that can be used with baseline risk values from any source.
Intraoperative Pacemaker Rate Changes Associated with the Rest Mode
Authors: Streckenbach Scott C.
Published: November 2008

Anesthesiologists frequently are required to provide perioperative management for patients with cardiac rhythm management devices. Here, I describe a case in which, despite efforts to ensure that the anesthesia care team understood the pacemaker and its settings, unanticipated pacing events occurred that created confusion about the status of the pacemaker in a pacemaker-dependent patient. The confusion was created by a relatively new function found in many current pacemakers, a rest mode.
Propofol
Authors: White Paul F. , Warner David S.
Published: November 2008

Pharmacokinetics and pharmacodynamics of propofol infusions during general anesthesia. By Audrey Shafer, Van A. Doze, Steven L. Shafer, and Paul F. White. Anesthesiology 1988; 69:348-56. Reprinted with permission.The pharmacokinetic and pharmacodynamic properties of propofol (Diprivan) were studied in 50 elective surgical patients. Propofol was administered as a bolus dose, 2 mg/kg iv, followed by a variable-rate infusion, 0-20 mg/min, and intermittent supplemental boluses, 10-20 mg iv, as part of a general anesthetic technique that included nitrous oxide, meperidine, and muscle relaxants. For a majority of the patients (n = 30), the pharmacokinetics of propofol were best described by a two-compartment model. The propofol mean total body clearance rate was 2.09 +/- 0.65 l/min (mean +/- SD), the volume of distribution at steady state was 159 +/- 57 l, and the elimination half-life was 116 +/- 34 min. Elderly patients (patients older than 60 yr vs. those younger than 60 yr) had significantly decreased clearance rates (1.58 +/- 0.42 vs. 2.19 +/- 0.64 l/min), whereas women (vs. men) had greater clearance rates (33 +/- 8 vs. 26 +/- 7 ml x kg x min ) and volumes of distribution (2.50 +/- 0.81 vs. 2.05 +/- 0.65 l/kg). Patients undergoing major (intraabdominal) surgery had longer elimination half-life values (136 +/- 40 vs. 108 +/- 29 min). Patients required an average blood propofol concentration of 4.05 +/- 1.01 micrograms/ml for major surgery and 2.97 +/- 1.07 micrograms/ml for nonmajor surgery. Blood propofol concentrations at which 50% of patients (EC50) were awake and oriented after surgery were 1.07 and 0.95 microgram/ml, respectively. Psychomotor performance returned to baseline at blood propofol concentrations of 0.38-0.43 microgram/ml (EC50). This clinical study demonstrates the feasibility of performing pharmacokinetic and pharmacodynamic analyses when complex infusion and bolus regimens are used for administering iv anesthetics.
On the complete integrability and linearization of nonlinear ordinary differential equations. III. Coupled first-order equations
Authors: Chandrasekar V.K , Senthilvelan M , Lakshmanan M
Published: November 2008

Continuing our study on the complete integrability of nonlinear ordinary differential equations (ODEs), in this paper we consider the integrability of a system of coupled first-order nonlinear ODEs of both autonomous and non-autonomous types. For this purpose, we modify the original Prelle–Singer (PS) procedure so as to apply it to both autonomous and non-autonomous systems of coupled first-order ODEs. We briefly explain the method of finding integrals of motion (time-independent as well as time-dependent integrals) for two and three coupled first-order ODEs by extending the PS method. From this we try to answer some of the open questions in the original PS method. We also identify integrable cases for the two-dimensional Lotka–Volterra system and three-dimensional Rössler system as well as other examples including non-autonomous systems in a straightforward way using this procedure. Finally, we develop a linearization procedure for coupled first-order ODEs.