bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods of experimental induction of periapical inflammation. Microbiological and radiographic evaluation
Authors: Tanomaru‐Filho M. , Poliseli‐Neto A. , Leonardo M. R. , Silva L. A. B. , Tanomaru J. M. G. , Ito I. Y. 
Published: March 2007

AbstractAim  To evaluate the influence of coronal filling and apical perforation on the induction of periapical inflammation.Methodology  Fifty‐eight root canals in the teeth of dogs were divided into four groups. Groups I and II: root canals were exposed for 180 days; groups III and IV: root canals were exposed for 7 days and then the access cavity filled for 53 days. The root apices of groups I and III were perforated after the coronal opening, whilst those of groups II and IV remained intact. Standard radiographs were taken before and after the experimental periods. Digital images of the radiographs were created and then analysed by three examiners. After induction of periapical inflammation, the root canal contents were collected using paper points. Microbiologic evaluation of the type of microorganism was carried out by culture in different growth media. The radiographic and microbiologic data were statistically analysed using anova at a 5% significance level.Results  There were a greater total number of microorganisms in groups I and II (P < 0.05). The number of anaerobes was greater than the number of aerobes (P < 0.05). The size of the periapical radiolucencies were not significantly different between the experimental groups.Conclusions  The different methods analysed induced similar areas of periapical radiolucency in dogs with predominantly anaerobic bacteria. However, the time required for induction was less when the method with coronal filling was used.
Short‐term antibacterial activity of root canal sealers towards Enterococcus faecalis
Authors: Kayaoglu G. , Erten H. , Alaçam T. , Ørstavik D. 
Published: March 2007

AbstractAim  To investigate the antimicrobial activity of root canal sealers on Enterococcus faecalis, either allowing or avoiding direct contact between sealers and bacteria.Methodology  Filter paper discs were immersed in standardized E. faecalis suspensions and exposed to freshly mixed sealers (MCS, AH Plus, Grossman's sealer, Sealapex, Apexit) in teflon wells for 30 min, with or without a filter membrane placed between filter paper discs and sealers (membrane‐restricted contact test and direct contact test, respectively). After exposure, the filter paper discs were transferred to vials containing phosphate‐buffered saline (PBS) and glass beads, and vigorously vortexed. PBS with resuspended bacterial cells was serially diluted and 25 μL droplets were seeded on TSA plates. The plates were incubated in air at 37 °C for 24 h and colony‐forming units were counted. Using α = 0.05 as level for statistical significance, the data obtained were analysed using Student's t‐test.Results  In the direct contact test, MCS and AH Plus killed the bacteria to a level below the detection limit. They were followed in decreasing order of efficacy by Grossman's sealer, Sealapex and Apexit. In the membrane‐restricted contact test, the sealers ranked: MCS, AH Plus, Grossman's sealer, Apexit and Sealapex, in descending order of antibacterial potency. MCS, AH Plus and Grossman's sealer significantly reduced the number of viable bacteria in both tests. Sealapex and Apexit were not statistically different from control.Conclusions  MCS, AH Plus and Grossman's sealer were effective in reducing the number of cultivable cells of E. faecalis. Calcium hydroxide‐based sealers, Sealapex and Apexit were ineffective in this short‐term experiment.
Mental health triage in the ER: a qualitative study
Authors: Coristine Ron W. , Hartford Kathleen , Vingilis Evelyn , White Dawn 
Published: March 2007

AbstractRationale, aims and objectives  The London Health Sciences Centre found that its emergency room (ER) mental health services were affected by people presenting with problems that did not require psychiatric intervention. Consequently, a second triage using a crisis worker (CW) was introduced in the ER to identify those persons with mental illness (PMI) who presented for social stressors related to housing, finances and legal issues. A qualitative, process evaluation study was conducted to capture experiences and perceptions of the new triage and CW.Method  Qualitative input was obtained from a broad range of stakeholders in three waves of data‐gathering over a 25‐month period. This method allowed corroboration of findings from informants with varying interests and backgrounds. The data were collected through interviews, focus groups and surveys. The NUD‐ist Qualitative Data Analysis Software Program was used to conduct content analyses.Results  Many PMI seeking ER mental health services are presenting with problems related to social stressors and being referred by the second triage to the CW. The introduction of the second triage CW has had a positive effect on ER functioning, the workload of ER staff and the experience of persons presenting at ER.Conclusions  A defined triage process coupled with the use of psychiatric nursing staff may be applicable to ERs within general hospital settings to improve ER functioning, focus support for PMI and further integrate ERs within the community mental health model.
Genetic differentiation between Príncipe Island and mainland populations of the grey parrot (Psittacus erithacus), and implications for conservation
Authors: MELO MARTIM , O’RYAN COLLEEN 
Published: March 2007

AbstractThe range of the grey parrot (Psittacus erithacus), one of the most heavily harvested bird species for the international pet trade, spans the forest belt of Central and West Africa and includes the oceanic island of Príncipe (Gulf of Guinea). Morphological variation led to the recognition of two mainland subspecies (P. e. erithacusandP. e. timneh). The population from Príncipe was originally described as a separate species (P. princeps) but is currently included in the nominate race. We used 1932 bp of the mitochondrial genome to clarify the genealogical affinities between the two currently‐recognized mainland subspecies and the Príncipe population. Sampling included 20 individuals from Príncipe, 17 fromP. e. erithacus, and 13 fromP. e. timneh. We found that the two mainland subspecies form two independent lineages, having diverged up to 2.4 million years ago (Ma), and that the Príncipe population is composed of two lineages that diverged in allopatry. The most common lineage is descended from the first colonizers and evolved in isolation for up to 1.4 Ma. Contrary to current understanding, this ‘Príncipe lineage’ is more closely related to thetimnehthan to theerithacussubspecies. The second lineage consists ofP. e. erithacusbirds from the nearby mainland that colonized the island in recent times. The evolutionary dynamics of the grey parrot population of Príncipe are primarily characterized by isolation, with new genetic variation being added through rare immigration events. The heavily harvested Príncipe grey parrot population should therefore be treated as an independent conservation unit.
The influence of altitude and topography on genetic structure in the long‐toed salamander (Ambystoma macrodactulym)
Authors: GIORDANO ANDREW R. , RIDENHOUR BENJAMIN J. , STORFER ANDREW 
Published: March 2007

AbstractA primary goal of molecular ecology is to understand the influence of abiotic factors on the spatial distribution of genetic variation. Features including altitudinal clines, topography and landscape characteristics affect the proportion of suitable habitat, influence dispersal patterns, and ultimately structure genetic differentiation among populations. We studied the effects of altitude and topography on genetic variation of long‐toed salamanders (Ambystoma macrodactylum), a geographically widespread amphibian species throughout northwestern North America. We focused on 10 low altitude sites (< 1200 m) and 11 high‐altitude sites in northwestern Montana and determined multilocus genotypes for 549 individuals using seven microsatellite loci. We tested four hypotheses: (1) gene flow is limited between high‐ and low‐altitude sites; and, (2) gene flow is limited among high‐altitude sites due to harsh habitat and extreme topographical relief between sites; (3) low‐altitude sites exhibit higher among‐site gene flow due to frequent flooding events and low altitudinal relief; and (4) there is a negative correlation between altitude and genetic variation. Overall FST values were moderate (0.08611; P < 0.001). Pairwise FST estimates between high and low populations and a population graphing method supported the hypothesis that low‐altitude and high‐altitude sites, taken together, are genetically differentiated from each other. Also as predicted, gene flow is more prominent among low‐altitude sites than high‐altitude sites; low‐altitude sites had a significantly lower FST (0.03995; P < 0.001) than high altitude sites (FST = 0.10271; P < 0.001). Use of Bayesian analysis of population structure (BAPS) resulted in delineation of 10 genetic groups, two among low‐altitude populations and eight among high‐altitude populations. In addition, within high altitude populations, basin‐level genetic structuring was apparent. A nonequilibrium algorithm for detecting current migration rates supported these population distinctions. Finally, we also found a significant negative correlation between genetic diversity and altitude. These results are consistent with the hypothesis that topography and altitudinal gradients shape the spatial distribution of genetic variation in a species with a broad geographical range and diverse life history. Our study sheds light on which key factors limit dispersal and ultimately species’ distributions.
Phylogenetic evidence for an animal pathogen origin of ergot and the grass endophytes
Authors: SPATAFORA J. W. , SUNG G.‐H. , SUNG J.‐M. , HYWEL‐JONES N. L. , WHITE J. F. 
Published: March 2007

AbstractGrass‐associated fungi (grass symbionts) in the family Clavicipitaceae (Ascomycota, Hypocreales) are species whose host range is restricted to the plant family Poaceae and rarely Cyperaceae. The best‐characterized species include Claviceps purpurea (ergot of rye) and Neotyphodium coenophialum (endophyte of tall fescue). They have been the focus of considerable research due to their importance in agricultural and grassland ecosystems and the diversity of their bioactive secondary metabolites. Here we show through multigene phylogenetic analyses and ancestral character state reconstruction that the grass symbionts in Clavicipitaceae are a derived group that originated from an animal pathogen through a dynamic process of interkingdom host jumping. The closest relatives of the grass symbionts include the genera Hypocrella, a pathogen of scale insects and white flies, and Metarhizium, a generalist arthropod pathogen. These data do not support the monophyly of Clavicipitaceae, but place it as part of a larger clade that includes Hypocreaceae, a family that contains mainly parasites of other fungi. A minimum of 5–8 independent and unidirectional interkingdom host jumps has occurred among clavicipitaceous fungi, including 3–5 to fungi, 1–2 to animals, and 1 to plants. These findings provide a new evolutionary context for studying the biology of the grass symbionts, their role in plant ecology, and the evolution of host affiliation in fungal symbioses.
Panmictic population structure in the hooded seal (Cystophora cristata)
Authors: COLTMAN D. W. , STENSON G. , HAMMILL M. O. , HAUG T. , DAVIS C. S. , FULTON T. L. 
Published: March 2007

AbstractTwo putative populations of hooded seals (Cystophora cristata) occur in the North Atlantic. The Greenland Sea population pup and breed on the pack ice near Jan Mayen (‘West Ice’) while the Northwest Atlantic population is thought to pup in the Davis Strait, in the Gulf of St. Lawrence (the ‘Gulf’), and off southern Labrador or northeast Newfoundland (the ‘Front’). We used microsatellite profiling of 300 individuals at 13 loci and mitochondrial DNA sequencing of the control region of 123 individuals to test for genetic differentiation between these four breeding herds. We found no significant genetic differences between breeding areas, nor evidence for cryptic nor higher level genetic structure in this species. The Greenland Sea breeding herd was genetically most distant from the Northwest Atlantic breeding areas; however, the differences were statistically nonsignificant. Our data therefore suggest that the world's hooded seals comprise a single panmictic genetic population.
Detecting genetic structure in migrating bowhead whales off the coast of Barrow, Alaska
Authors: JORDE P. E. , SCHWEDER T. , BICKHAM J. W. , GIVENS G. H. , SUYDAM R. , HUNTER D. , STENSETH N. C. 
Published: March 2007

AbstractWe develop a general framework for analysing and testing genetic structure within a migratory assemblage that is based on measures of genetic differences between individuals. We demonstrate this method using microsatellite DNA data from the Bering‐Chukchi‐Beaufort stock of bowhead whales (Balaena mysticetus), sampled via Inuit hunting during the spring and autumn migration off Barrow, Alaska. This study includes a number of covariates such as whale ages and the time separation between captures. Applying the method to a sample of 117 bowhead whales, we use permutation methods to test for temporal trends in genetic differences that can be ascribed to age‐related effects or to timing of catches during the seasons. The results reveal a pattern with elevated genetic differences among whales caught about a week apart, and are statistically significant for the autumn migration. In contrast, we find no effects of time of birth or age‐difference on genetic differences. We discuss possible explanations for the results, including population substructuring, demographic consequences of historical overexploitation, and social structuring during migration.
The auxin‐binding protein 1 is essential for the control of cell cycle
Authors: David Karine M. , Couch Daniel , Braun Nils , Brown Spencer , Grosclaude Jeanne , Perrot‐Rechenmann Catherine 
Published: March 2007

SummaryThe phytohormone auxin has been known for >50 years to be required for entry into the cell cycle. Despite the critical effects exerted by auxin on the control of cell division, the molecular mechanism by which auxin controls this pathway is poorly understood, and how auxin is perceived upstream of any change in the cell cycle is unknown. Auxin Binding Protein 1 (ABP1) is considered to be a candidate auxin receptor, triggering early modification of ion fluxes across the plasma membrane in response to auxin. ABP1 has also been proposed to mediate auxin‐dependent cell expansion, and is essential for early embryonic development. We investigated whether ABP1 has a role in the cell cycle. Functional inactivation of ABP1 in the model plant cell system BY2 was achieved through cellular immunization via the conditional expression of a single‐chain fragment variable (scFv). This scFv was derived from a well characterized anti‐ABP1 monoclonal antibody previously shown to block the activity of the protein. We demonstrate that functional inactivation of ABP1 results in cell‐cycle arrest, and provide evidence that ABP1 plays a critical role in regulation of the cell cycle by acting at both the G1/S and G2/M checkpoints. We conclude that ABP1 is essential for the auxin control of cell division and is likely to constitute the first step of the auxin‐signalling pathway mediating auxin effects on the cell cycle.
Composition of alkyl esters in the cuticular wax on inflorescence stems of Arabidopsis thaliana cer mutants
Authors: Lai Christine , Kunst Ljerka , Jetter Reinhard 
Published: March 2007

AbstractWax biosynthetic pathways proceed via the elongation of 16:0 acyl‐CoA to very long‐chain fatty acids (VLCFA), and by further modifications that include reduction to primary alcohols and formation of alkyl esters. We have analyzed the alkyl esters in the stem wax of ten cer mutants of Arabidopsis thaliana together with the corresponding wild types. Alkyl esters with chain lengths between C38 and C52 were identified, and the levels of esters ranged from 0.15 µg cm−2 in Wassilewskija (WS) to 1.20 µg cm−2 in cer2. Esters with even numbers of carbons prevailed, with C42, C44 and C46 favoured in the wild types, a predominance of C42 in cer2 and cer6 mutants, and a relative shift towards C46 in cer3 and cer23 mutants. The esters of all mutants and wild types were dominated by 16:0 acyl moieties, whereas the chain lengths of esterified alcohols were between C20 and C32. The alkyl chain‐length distributions of the wild‐type esters had a maximum for C28 alcohol, similar to the free alcohols accompanying them in the wax mixtures. The esterified alcohols of cer2, cer6 and cer9 had largely increased levels of C26 alcohol, closely matching the patterns of the corresponding free alcohols and, therefore, differing drastically from the corresponding wild type. In contrast, cer1, cer3, cer10, cer13 and cer22 showed ester alcohol patterns with increased levels of C30, only partially following the shift in chain lengths of the free alcohols in stem wax. These results provide information on the composition of substrate pools and/or the specificity of the ester synthase involved in wax ester formation. We conclude that alcohol levels at the site of biosynthesis are mainly limiting the ester formation in the Arabidopsis wild‐type epidermis.
Further in vivo studies on the role of the molecular chaperone, Hsp93, in plastid protein import
Authors: Kovacheva Sabina , Bédard Jocelyn , Wardle Anthony , Patel Ramesh , Jarvis Paul 
Published: March 2007

SummaryIn Arabidopsis, Hsp93 is encoded by two genes, atHSP93‐V and atHSP93‐III. We identified two T‐DNA mutants for atHSP93‐III: one being a partial ‘knockdown’ (hsp93‐III‐1) and the other a complete ‘knockout’ (hsp93‐III‐2). Homozygotes for both mutants were indistinguishable from wild type. We crossed each mutant to an atHSP93‐V knockout, and identified double mutants with strongly chlorotic phenotypes. This implied redundancy, which was confirmed by the complementation of mildly chlorotic hsp93‐V plants by atHSP93‐III over‐expression. While the hsp93‐V hsp93‐III‐1 mutant was doubly homozygous, the second double mutant was heterozygous for hsp93‐III‐2 (genotype: hsp93‐V/hsp93‐V; +/hsp93‐III‐2). Attempts to identify an hsp93‐V hsp93‐III‐2 double homozygote were unsuccessful, indicating that the Hsp93 pool is essential for viability. Consistently, siliques of the second double mutant contained aborted seeds (because of a block in the zygote–embryo transition) and failed ovules (because of a moderate defect in female gametophytes). Double‐mutant plants were chlorophyll‐deficient, contained under‐developed chloroplasts, and exhibited stunted growth. In import assays using a chimeric pre‐protein (plastocyanin transit peptide fused to dihydrofolate reductase; PC‐DHFR), a clear defect was observed in hsp93‐V hsp93‐III‐1 chloroplasts. Interestingly, while denaturation or stabilization of the DHFR moiety had a strong effect on import efficiency in the wild type, no such effects were observed with double‐mutant (or tic40) chloroplasts. This indicated that pre‐protein unfolding is not rate‐limiting for import into mutant chloroplasts, and suggested that (unlike the situation in mitochondria) the inner membrane import machinery does not contribute to pre‐protein unfolding at the organellar surface.
ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation
Authors: Oracz Krystyna , Bouteau Hayat El‐Maarouf , Farrant Jill M. , Cooper Keren , Belghazi Maya , Job Claudette , Job Dominique , Corbineau Françoise , Bailly Christophe 
Published: March 2007

SummaryAt harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15°C. Seed storage in the dry state, known as after‐ripening, is associated with an alleviation of embryonic dormancy allowing subsequent germination at suboptimal temperatures. To identify the process by which dormancy is broken during after‐ripening, we focused on the role of reactive oxygen species (ROS) in this phenomenon. After‐ripening entailed a progressive accumulation of ROS, namely superoxide anions and hydrogen peroxide, in cells of embryonic axes. This accumulation, which was investigated at the cellular level by electron microscopy, occurred concomitantly with lipid peroxidation and oxidation (carbonylation) of specific embryo proteins. Incubation of dormant seeds for 3 h in the presence of hydrogen cyanide (a compound that breaks dormancy) or methylviologen (a ROS‐generating compound) also released dormancy and caused the oxidation of a specific set of embryo proteins. From these observations, we propose a novel mechanism for seed dormancy alleviation. This mechanism involves ROS production and targeted changes in protein carbonylation patterns.
A reporter system for the individual detection of hydrogen peroxide and singlet oxygen: its use for the assay of reactive oxygen species produced in vivo
Authors: Shao Ning , Krieger‐Liszkay Anja , Schroda Michael , Beck Christoph F. 
Published: March 2007

SummaryA reporter system for the assay of reactive oxygen species (ROS) was developed in Chlamydomonas reinhardtii, a plant model organism well suited for the application of inhibitors and generators of various types of ROS. This system employs various HSP70A promoter segments fused to a Renilla reniformis luciferase gene as a reporter. Transformants with the complete HSP70A promoter were inducible by both hydrogen peroxide and singlet oxygen. Constructs that lacked upstream heat‐shock elements (HSEs) were inducible by hydrogen peroxide, indicating that this induction does not require such HSEs. Rather, downstream elements located between positions −81 to −149 with respect to the translation start site appear to be involved. In contrast, upstream sequences are essential for the response to singlet oxygen. Thus, activation by singlet oxygen appears to require promoter elements that are different from those used by hydrogen peroxide. ROS generated endogenously by treatment of the alga with metronidazole, protoporphyrin IX, dinoterb or high light intensities were detected by this reporter system, and distinguished as production of hydrogen peroxide (metronidazole) and singlet oxygen (protoporphyrin IX, dinoterb, high light). This system thus makes it possible to test whether, under varying environmental conditions including the application of abiotic stress, hydrogen peroxide or singlet oxygen or both are produced.