bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative trait loci associated with isolate specific and isolate nonspecific partial resistance to Phoma macdonaldii in sunflower
Authors: Darvishzadeh R. , Kiani S. Poormohammad , Dechamp‐Guillaume G. , Gentzbittel L. , Sarrafi A. 
Published: June 2007

Black stem, caused by Phoma macdonaldii, is one of the most important diseases of sunflower in the world. Quantitative trait loci (QTLs) implicated in partial resistance to two single pycnidiospore isolates of P. macdonaldii (MP8 and MP10) were investigated using 99 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. The experimental design was a randomized complete block with three replications. High genetic variability and transgressive segregation were observed among RILs for partial resistance to P. macdonaldii isolates. QTL‐mapping was performed using a recently developed high‐density SSR/AFLP sunflower linkage map. A total of 10 QTLs were detected for black stem resistance. The phenotypic variance explained by each QTL (R2) was moderate, ranging from 6 to 20%. Four QTLs were common between two isolates on linkage group 5 and 15 whereas the others were specific for each isolate. Regarding isolate‐specific and isolate‐nonspecific QTLs detected for partial resistance, it is evident that both genetic effects control partial resistance to the disease isolates. This confirms the need to consider different isolates in the black stem resistance breeding programmes. The four SSR markers HA3700, SSU25, ORS1097 and ORS523_1 encompassing the QTLs for partial resistance to black stem isolates could be good candidates for marker assisted selection.
Efficient, long‐lasting resistance against the soft rot bacterium Pectobacterium carotovorum in calla lily provided by the plant activator methyl jasmonate
Authors: Luzzatto T. , Yishay M. , Lipsky A. , Ion A. , Belausov E. , Yedidia I. 
Published: June 2007

The potential of three externally applied chemical plant activators, Bion, BABA and methyl jasmonate, known to act only through the plant defence system and not on the pathogen directly, to induce resistance against wild‐type Pectobacterium carotovorum was examined in white‐flowered calla lily (Zantedeschia aethiopica). Following a 24‐h induction period, plants were challenge‐inoculated with P. carotovorum, originally isolated from calla lily or potato plants, previously transformed using a gfp broad‐host‐range promoter‐probe vector. After another 24 h, Bion treatment (10 µg mL−1, as a drench) reduced disease symptoms more than sixfold and bacterial proliferation by four orders of magnitude. BABA treatment (5–10 µg mL−1, also as a drench) reduced the rate of infection by 75–85%. However, the protection afforded by both inducers did not persist. Also, at higher concentrations both displayed a phytotoxic effect. By contrast, methyl jasmonate (10 mm, applied as a leaf spray) completely inhibited P. carotovorum development in calla lily leaves and afforded a long‐lasting effect. It is suggested that the defence response of calla lily against P. carotovorum involves the SA‐signalling pathway in the short term, but the jasmonate/ethylene‐signalling pathway is required for durable protection.
Growth mechanism of snowball garnets from the Lukmanier Pass area (Central Alps, Switzerland): a combined μCT/EPMA/EBSD study
Authors: Robyr Martin , Vonlanthen Pierre , Baumgartner Lukas P. , Grobety Bernard 
Published: June 2007

AbstractFor two decades, considerable efforts have been made to explain the formation of snowball garnets by either the rotational or non‐rotational models. On the basis of morphological, chemical and crystallographic evidence, this paper presents new data on snowball garnets showing that the formation of these microstructures can be explained by the combination of the two previously proposed mechanisms operating consecutively during garnet growth. The crystallization sequence of garnet revealed by Mn contouring and the distribution of crystallographic orientations within the spiral indicate that the final stages of garnet growth are controlled by post‐kinematic crystallization. However, some microstructural arguments plead for a rotational contribution during the first stages of growth. In this view, the overall spiral geometry is thought to overestimate the true amount of rotation experienced by the garnets. Results also reveal the existence of complex snowball garnets consisting of several grains formed from distinct nucleation sites.
A possible impact crater for the 1908 Tunguska Event
Authors: Gasperini L. , Alvisi F. , Biasini G. , Bonatti E. , Longo G. , Pipan M. , Ravaioli M. , Serra R. 
Published: June 2007

AbstractThe so‐called ‘Tunguska Event’ refers to a major explosion that occurred on 30 June 1908 in the Tunguska region of Siberia, causing the destruction of over 2000 km2 of taiga, globally detected pressure and seismic waves, and bright luminescence in the night skies of Europe and Central Asia, combined with other unusual phenomena. The ‘Tunguska Event’ may be related to the impact with the Earth of a cosmic body that exploded about 5–10 km above ground, releasing in the atmosphere 10–15 Mton of energy. Fragments of the impacting body have never been found, and its nature (comet or asteroid) is still a matter of debate. We report results from the investigation of Lake Cheko, located ∼8 km NNW of the inferred explosion epicenter. Its funnel‐like bottom morphology and the structure of its sedimentary deposits, revealed by acoustic imagery and direct sampling, all suggest that the lake fills an impact crater. Lake Cheko may have formed due to a secondary impact onto alluvial swampy ground; the size and shape of the crater may have been affected by the nature of the ground and by impact‐related melting and degassing of a permafrost layer.
Layered basal defenses underlie non‐host resistance of Arabidopsis to Pseudomonas syringae pv. phaseolicola
Authors: Ham Jong Hyun , Kim Min Gab , Lee Sang Yeol , Mackey David 
Published: June 2007

SummaryArabidopsis is a non‐host for Pseudomonas syringae pv. phaseolicola NPS3121 (Pph), a bacterial pathogen of bean. Pph does not induce a hypersensitive response in Arabidopsis. Here we show that Arabidopsis instead resists Pph with multi‐layered basal defense. Our approach was: (i) to identify defense readouts induced by Pph; (ii) to determine whether mutations in known Arabidopsis defense genes disrupt Pph‐induced defense signaling; (iii) to determine whether heterologous type III effectors from pathogens of Arabidopsis suppress Pph‐induced defense signaling, and (iv) to ascertain how basal defenses contribute to resistance against Pph by individually or multiply disrupting defense signaling pathways with mutations and heterologous type III effectors. We demonstrate that Pph elicits a minimum of three basal defense‐signaling pathways in Arabidopsis. These pathways have unique readouts, including PR‐1 protein accumulation and morphologically distinct types of callose deposition. Further, they require distinct defense genes, including PMR4, RAR1, SID2, NPR1, and PAD4. Finally, they are suppressed differentially by heterologous type III effectors, including AvrRpm1 and HopM1. Pph growth is enhanced only when multiple defense pathways are disrupted. For example, mutation of NPR1 or SID2 combined with the action of AvrRpm1 and HopM1 renders Arabidopsis highly susceptible to Pph. Thus, non‐host resistance of Arabidopsis to Pph is based on multiple, individually effective layers of basal defense.
Semagenesis and the parasitic angiosperm Striga asiatica
Authors: Keyes William John , Palmer Andrew G. , Erbil William Kaya , Taylor Jeannette V. , Apkarian Robert P. , Weeks Eric R. , Lynn David G. 
Published: June 2007

SummaryOver the last several years, intermediates in the reduction of dioxygen have been attributed diverse functional roles ranging from protection against pathogen attack to the regulation of cellular development. Evidence now suggests that parasitic angiosperms, which naturally commit to virulence through the growth of new organs, depend on reduced oxygen intermediates, or reactive oxygen species (ROS), for signal generation. Clearly, the role of ROS in both plant defense and other physiological responses complicates any models that employ these intermediates in host plant recognition. Here we exploit the transparent youngStriga asiaticaseedling to (i) localize the site of H2O2accumulation to the surface cells of the primary root meristem, (ii) demonstrate the accumulation of H2O2within cytoplasmic and apoplastic compartments, and (iii) document precise regulation of H2O2accumulation during development of the host attachment organ, the haustorium. These studies reveal a new active process for signal generation, host detection and commitment that is capable of ensuring the correct spatial and temporal positioning for attachment.
A petunia mutant affected in intracellular accommodation and morphogenesis of arbuscular mycorrhizal fungi
Authors: Reddy D. M. R. Sekhara , Schorderet Martine , Feller Urs , Reinhardt Didier 
Published: June 2007

SummaryThe regulation of the arbuscular mycorrhizal (AM) symbiosis is largely under the control of a genetic programme of the plant host. This programme includes a common symbiosis signalling pathway that is shared with the root nodule symbiosis. Whereas this common pathway has been investigated in detail, little is known about the mycorrhiza‐specific regulatory steps upstream and downstream of the common pathway. To get further insight in the regulation of the AM symbiosis, a transposon‐mutagenized population of Petunia hybrida was screened for mutants with defects in AM development. Here, we describe a petunia mutant, penetration and arbuscule morphogenesis1 (pam1), which is characterized by a strong decrease in colonization by three different AM fungi. Penetrating hyphae are frequently aborted in epidermal cells. Occasionally the fungus can progress to the cortex, but fails to develop arbuscules. The resulting hyphal colonization of the cortex in mutant plants does not support symbiotic acquisition of phosphate and copper by the plant. Expression analysis of three petunia orthologues of the common SYM genes LjPOLLUX, LjSYMRK and MtDMI3 indicates that pam1 is not mutated in these genes. We conclude that the PAM1 gene may play a specific role in intracellular accommodation and morphogenesis of the fungal endosymbiont.
CLINICAL STUDY: Endogenous morphine signaling via nitric oxide regulates the expression of CYP2D6 and COMT: autocrine/paracrine feedback inhibition
Authors: Mantione Kirk J. , Cadet Patrick , Zhu Wei , Kream Richard M. , Sheehan Melinda , Fricchione Gregory L. , Goumon Yannick , Esch Tobias , Stefano George B. 
Published: June 2007

ABSTRACTWe determined changes in mRNA expression in specific enzymes involved in the biosynthesis of morphine in human white blood cells via microarray. Leukocyte exposure to morphine down‐regulated catechol‐O‐methyl transferase (COMT) and CYP2D6 by approximately 50% compared with control values. The treatment did not alter DOPA decarboxylase and dopamine beta‐hydroxylase expression, demonstrating the specificity of morphine actions. The verification of the microarray data was accomplished via real‐time Taqman reverse transcriptase polymerase chain reaction (RT‐PCR) focused on CYP2D6 and COMT expression in different blood samples treated with morphine. The analysis showed similar changes in the expression of CYP2D6 and COMT mRNA. The expression was reduced by 47 ± 7% for CYP2D6, substantiating the microarray finding of a 54% reduction. Furthermore, exposure of white blood cells to 10−6 M S‐nitroso‐N‐acetyl‐dl‐penicillamine (SNAP), a nitric oxide (NO) donor, reduced the expression of CYP2D6 and COMT. Prior naloxone (10−6 M) or N‐nitro‐l‐arginine methyl ester (l‐NAME) (10−4 M) addition abrogated morphine’s down‐regulating activity, demonstrating morphine was initiating its actions via stimulating constitutive NO synthase derived NO release via the µ3 opiate receptor splice variant. In the past we demonstrated that UDP‐glucurosyltransferase is involved in metabolizing morphine to morphine 6‐glucuronide in adrenal chromaffin cells. In the present study its expression was not found in controls and morphine‐treated cells, suggesting that morphine 6‐glucuronide may not be synthesized in white blood cells. Taken together, it appears that morphine has the ability to modulate its own synthesis via autocrine and paracrine signaling.
CLINICAL STUDY: Cloninger’s typology and treatment outcome in alcohol‐dependent subjects during pharmacotherapy with naltrexone
Authors: Kiefer Falk , Jiménez‐Arriero Miguel Angel , Klein Oliver , Diehl Alexander , Rubio Gabriel 
Published: June 2007

ABSTRACTNaltrexone is an opiate receptor antagonist mainly at the µ‐receptor that is thought to reduce the positively reinforcing, pleasurable effects of alcohol and to reduce craving. An increase in time to first relapse to heavy drinking has been the most consistent finding obtained with naltrexone, although not all trials including two of the largest have been positive. Inconsistent outcome data suggest that effectiveness varies among different subgroups of patients. This paper re‐evaluates recent data on the effectiveness of naltrexone in subjects differentiated according to Cloninger Type I and II. Moreover, it combines and cross‐validates results of two recent European studies that found naltrexone treatment more beneficial in alcohol‐dependent patients with early age at onset of drinking problems (Cloninger Type II). It is discussed whether especially these subjects should be targeted for pharmacological relapse prevention treatment with naltrexone.
IMAGING STUDY: Selectively reduced responses to smoking cues in amygdala following extinction‐based smoking cessation: results of a preliminary functional magnetic resonance imaging study
Authors: McClernon F. Joseph , Hiott F. Berry , Liu Jim , Salley Alfred N. , Behm Frederique M. , Rose Jed E. 
Published: June 2007

ABSTRACTPreliminary studies suggest an extinction‐based smoking cessation treatment using reduced nicotine content (RNC) cigarettes decreases self‐report craving for cigarettes prior to quitting and may be an effective smoking cessation treatment. The aims of this study was to evaluate the effect of an extinction‐based smoking cessation treatment on brain responses to smoking cues using blood‐oxygen level‐dependent (BOLD) functional magnetic resonance imaging (fMRI). Sixteen (n = 16) dependent smokers were scanned using BOLD fMRI at baseline, following 2–4 weeks of smoking RNC cigarettes while wearing a 21‐mg nicotine patch, and 2–4 weeks following quitting smoking. During scanning, participants viewed smoking‐related pictures (e.g. lit cigarette) and pictures of people engaged in everyday activities (e.g. using a stapler). Event‐related BOLD responses to smoking and control cues were analyzed in regions of interest (ROIs) known to subserve reward, attention, motivation and emotion. The extinction‐based treatment simultaneously attenuated responses to smoking cues in amygdala while potentiating responses to control cues. Exploratory analysis indicated that this pattern was also observed in the thalamus of future abstinent but not relapsing smokers. The results of this preliminary study suggest that an extinction‐based treatment for smoking cessation alters brain responses to smoking and control cues in amygdala—a region previously associated with drug cue reactivity and extinction.
Bronchial responsiveness to methacholine and adenosine 5′‐monophosphate in young children with asthma: their relationship with blood eosinophils and serum eosinophil cationic protein
Authors: Choi S. H. , Kim D. K. , Yu J. , Yoo Y. , Koh Y. Y. 
Published: June 2007

Background:  Bronchial hyperresponsiveness is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. Blood eosinophil numbers and serum levels of eosinophil cationic protein (ECP) are considered as indirect measures of airway inflammation in asthma. The aim of this study was to investigate whether bronchial responsiveness to adenosine 5′‐monophosphate (AMP) is more closely associated with blood eosinophil markers, compared with that to methacholine, in young children with asthma.Methods:  Methacholine and AMP bronchial challenges were performed in 4‐ to 6‐year‐old children with asthma (n = 77) and in healthy controls (n = 32), using a modified auscultation method. The end‐point was defined as the appearance of wheezing and/or oxygen desaturation. The peripheral blood eosinophil counts and serum ECP concentrations were determined in each subject.Results:  A positive response to methacholine (end‐point concentration ≤8 mg/ml) and to AMP (end‐point concentration ≤200 mg/ml) was observed in 74 (96.1%) and 66 asthmatic children (85.7%), respectively. A majority of controls was unresponsive to both challenges. In the asthma group, there was no significant correlation between methacholine end‐point concentration and the eosinophil counts (r = −0.111, P = 0.337) or serum ECP levels (r = −0.126, P = 0.274). In contrast, AMP end‐point concentration correlated significantly with the eosinophil counts (r = −0.372, P = 0.001) and with serum ECP levels (r = −0.371, P = 0.001).Conclusions:  Our results suggest that bronchial responsiveness to AMP is more closely related to airway inflammation, compared with that to methacholine, and support the potential usefulness of AMP challenges in detecting inflammatory changes in young children with asthma.
Does foraging mode mould morphology in lacertid lizards?
Authors: VERWAIJEN D. , VAN DAMME R. 
Published: June 2007

AbstractEvolutionary changes in foraging style are often believed to require concurrent changes in a complex suite of morphological, physiological, behavioural and life‐history traits. In lizards, species from families with a predominantly sit‐and‐wait foraging style tend to be more stocky and robust, with larger heads and mouths than species belonging to actively foraging families. Here, we test whether morphology and foraging behaviour show similar patterns of association within the family Lacertidae. We also examine the association of bite force abilities with morphology and foraging behaviour. Lacertid lizards exhibit considerable interspecific variation in foraging indices, and we found some evidence for a covariation between foraging style and body shape. However, the observed relationships are not always in line with the predictions. Also, the significance of the relationships varies with the evolutionary model used. Our results challenge the idea that foraging style is evolutionarily conservative and invariably associated with particular morphologies. It appears that the flexibility of foraging mode and its morphological correlates varies among lizard taxa.
The role of marker traits in the assortative mating within red crossbills, Loxia curvirostra complex
Authors: SNOWBERG L. K. , BENKMAN C. W. 
Published: June 2007

AbstractWe conducted mate choice experiments to determine whether differences in calls or bill morphology might influence assortative mating between call types of red crossbills (Loxia curvirostra complex) that have diverged in bill structure to specialize on different species of conifers. Females preferred males that gave calls that matched their own type, but did not prefer males that more closely approximated the average or optimal bill size of the female's call type. These results were consistent with our breeding simulations, which showed that females gained an indirect fitness benefit by choosing a male of her own call type because this reduced the production of offspring with morphologies that fell between adaptive peaks. However, choice based on bill morphology within a call type provided no further benefit. Calls, which crossbills learn from their parents, likely act as a marker trait indicative of the morphological adaptations of the group, allow for easy assessment of potential mates and facilitate rapid divergence under ecological selection.
Phylogenetic analysis of interspecific variation in nectar of hummingbird‐visited plants
Authors: ORNELAS J. F. , ORDANO M. , DE‐NOVA A. J. , QUINTERO M. E. , GARLAND T. 
Published: June 2007

AbstractWe tested whether phylogeny, flower size and/or altitude were significant predictors of interspecific variation in nectar production of hummingbird‐visited plants in an assembled database (289 species, in 22 orders, 56 families and 131 genera). Although the study is focused on hummingbird‐pollinated plants (241 plant species), plants with different pollinator syndromes (48 species) are also included in the analyses. Nectar volume secreted in a given time period (usually 24 h) by a given flower, its sugar concentration and corolla length were compiled mainly from the literature. Altitude was also obtained from the original references. Sugar production was computed basically as the product of nectar secretion and sugar concentration, and expressed on a per 24‐h basis. All nectar traits and corolla length (all log transformed), as well as altitude, showed statistically significant phylogenetic signal. Both nonphylogenetic and phylogenetically informed (independent contrasts) analyses indicated a highly significant positive correlation between corolla length and both nectar volume and sugar production. In addition, altitude (which is partially a surrogate for temperature) was significantly negatively correlated with both sugar concentration and production. Possible reasons for coadaptation of nectar production and sugar production with corolla length are discussed.
Strong artificial selection in the wild results in predicted small evolutionary change
Authors: POSTMA E. , VISSER J. , VAN NOORDWIJK A. J. 
Published: June 2007

AbstractEstimates of genetic variation and selection allow for quantitative predictions of evolutionary change, at least in controlled laboratory experiments. Natural populations are, however, different in many ways, and natural selection on heritable traits does not always result in phenotypic change. To test whether we were able to predict the evolutionary dynamics of a complex trait measured in a natural, heterogeneous environment, we performed, over an 8‐year period, a two‐way selection experiment on clutch size in a subdivided island population of great tits (Parus major). Despite strong artificial selection, there was no clear evidence for evolutionary change at the phenotypic level. Environmentally induced differences in clutch size among years are, however, large and can mask evolutionary changes. Indeed, genetic changes in clutch size, inferred from a statistical model, did not deviate systematically from those predicted. Although this shows that estimates of genetic variation and selection can indeed provide quantitative predictions of evolutionary change, also in the wild, it also emphasizes that demonstrating evolution in wild populations is difficult, and that the interpretation of phenotypic trends requires great care.
Influence of genetic dissimilarity in the reproductive success and mate choice of brown trout – females fishing for optimal MHC dissimilarity
Authors: FORSBERG L.A. , DANNEWITZ J. , PETERSSON E. , GRAHN M. 
Published: June 2007

AbstractWe examined the reproductive success of 48 adult brown trout (Salmo trutta L.) which were allowed to reproduce in a stream that was controlled for the absence of other trout. Parentage analyses based on 11 microsatellites permitted us to infer reproductive success and mate choice preferences in situ. We found that pairs with intermediate major histocompatibility complex (MHC) dissimilarity mated more often than expected by chance. It appears that female choice was the driving force behind this observation because, compared with other individuals, males with intermediate MHC dissimilarity produced a larger proportion of offspring, whereas female reproductive output did not show this pattern. Hence, rather than seeking mates with maximal MHC dissimilarity, as found in several species, brown trout seemed to prefer mates of intermediate MHC difference, thus supporting an optimality‐based model for MHC‐dependent mate choice.