bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Matrigel on adenoid cystic carcinoma cell line differentiation
Authors: Marques Márcia M. , Martins Manoela D. , França Cristiane M. 
Published: August 2006

SummaryAdenoid cystic carcinoma (ACC) is a frequent malignant salivary gland neoplasm presenting different growth patterns described as tubular, cribriform and solid, which represent distinct differentiation stages. Cell lines originated from ACCs grown inside three‐dimensional environments have not been capable to reproduce all in vivo ACC growth patterns. As ACC cells in vivo present replicated basement membrane, to mimic this situation in vitro ACC cells (CAC2 cells) were grown on the top of a reconstituted basement membrane (Matrigel). Phenotype differences were assessed by light, fluorescence and transmission electron microscopy. The cultures grown on the top of Matrigel presented three‐dimensional arrangement of cells intercepted by cellular cords. At these, cell nests pseudocyst formations were observed. This morphological structure entirely reproduced the cribriform growth pattern of ACC. We suggest that the cribriform differentiation of ACC in culture is dependent of proteins and growth factors associated in a bi‐dimensional structure.
Cognitive‐behavioural stress management does not improve biological cardiovascular risk indicators in women with ischaemic heart disease: a randomized‐controlled trial
Authors: CLAESSON M. , BIRGANDER L. S. , JANSSON J.‐H. , LINDAHL B. , BURELL G. , ASPLUND K. , MATTSSON C. 
Published: August 2006

Abstract.Objectives.  Psychosocial factors, such as stress and vital exhaustion, are associated with an increased risk of cardiovascular events, and women report more psychosocial ill‐being after an acute myocardial infarction than men. We have earlier shown that a cognitive‐behavioural intervention in women with ischaemic heart disease (IHD) improved psychosocial well‐being. In the present study, we tested the hypothesis that the improvement in psychosocial well‐being is associated with an improvement in biochemical indicators of cardiovascular risk.Design.  Randomized‐controlled trial in northern Sweden.Setting.  Outpatient care.Subjects.  Women with IHD were randomized to either a 1‐year cognitive‐behavioural stress management programme or usual care. Of the 159 women who completed the study, 77 were in the intervention group, and 82 in the control group.Interventions.  A 1‐year cognitive‐behavioural stress management programme versus conventional care.Results.  Group assignment was not found to be a determinant of waist circumference, high sensitive C‐reactive protein (hs‐CRP), fibrinogen, von Willebrand factor (vWF), plasminogen activator inhibitor type 1 (PAI‐1) activity, tissue plasminogen activator (tPA) activity, tPA antigen, tPA–PAI‐1 complex, leptin, or HOMA2 insulin resistance index (HOMA2‐IR) at follow up. Changes in psychosocial variables were not associated with changes in any of the biological risk indicators.Conclusions.  Even if our cognitive‐behavioural stress management programme had effects on proximal targets, such as stress behaviour and vital exhaustion, we found no improvement in intermediate biochemical targets related to the metabolic syndrome and IHD. Our results challenge the proposition that the relationship between psychological well‐being and biological cardiovascular risk indicators is a direct cause–effect phenomenon.
Phylogeography and Pleistocene refugia of the adder (Vipera berus) as inferred from mitochondrial DNA sequence data
Authors: URSENBACHER S. , CARLSSON M. , HELFER V. , TEGELSTRÖM H. , FUMAGALLI L. 
Published: August 2006

AbstractIn order to contribute to the debate about southern glacial refugia used by temperate species and more northern refugia used by boreal or cold‐temperate species, we examined the phylogeography of a widespread snake species (Vipera berus) inhabiting Europe up to the Arctic Circle. The analysis of the mitochondrial DNA (mtDNA) sequence variation in 1043 bp of the cytochrome b gene and in 918 bp of the noncoding control region was performed with phylogenetic approaches. Our results suggest that both the duplicated control region and cytochrome b evolve at a similar rate in this species. Phylogenetic analysis showed that V. berus is divided into three major mitochondrial lineages, probably resulting from an Italian, a Balkan and a Northern (from France to Russia) refugial area in Eastern Europe, near the Carpathian Mountains. In addition, the Northern clade presents an important substructure, suggesting two sequential colonization events in Europe. First, the continent was colonized from the three main refugial areas mentioned above during the Lower‐Mid Pleistocene. Second, recolonization of most of Europe most likely originated from several refugia located outside of the Mediterranean peninsulas (Carpathian region, east of the Carpathians, France and possibly Hungary) during the Mid‐Late Pleistocene, while populations within the Italian and Balkan Peninsulas fluctuated only slightly in distribution range, with larger lowland populations during glacial times and with refugial mountain populations during interglacials, as in the present time. The phylogeographical structure revealed in our study suggests complex recolonization dynamics of the European continent by V. berus, characterized by latitudinal as well as altitudinal range shifts, driven by both climatic changes and competition with related species.
Phytochrome‐mediated development in land plants: red light sensing evolves to meet the challenges of changing light environments
Authors: MATHEWS SARAH 
Published: August 2006

AbstractPhytochromes are photoreceptors that provide plants with circadian, seasonal, and positional information critical for the control of germination, seedling development, shade avoidance, reproduction, dormancy, and sleep movements. Phytochromes are unique among photoreceptors in their capacity to interconvert between a red‐absorbing form (absorption maximum of ∼660 nm) and a far‐red absorbing form (absorption maximum of ∼730 nm), which occur in a dynamic equilibrium within plant cells, corresponding to the proportions of red and far‐red energy in ambient light. Because pigments in stems and leaves absorb wavelengths below about 700 nm, this provides plants with an elegant system for detecting their position relative to other plants, with which the plants compete for light. Certain aspects of phytochrome‐mediated development outside of flowering plants are strikingly similar to those that have been characterized inArabidopsis thalianaand other angiosperms. However, early diverging land plants have fewer distinct phytochrome gene lineages, suggesting that both diversification and subfunctionalization have been important in the evolution of the phytochrome gene family. There is evidence that subfunctionalization proceeded by the partitioning among paralogues of photosensory specificity, physiological response modes, and light‐regulated gene expression and protein stability. Parallel events of duplication and functional divergence may have coincided with the evolution of canopy shade and the increasing complexity of the light environment. Within angiosperms, patterns of functional divergence are clade‐specific and the roles of phytochromes inA. thalianachange across environments, attesting to the evolutionary flexibility and contemporaneous plasticity of phytochrome signalling in the control of development.
The genetic structure of Australasian green turtles (Chelonia mydas): exploring the geographical scale of genetic exchange
Authors: DETHMERS KIKI E. M. , BRODERICK DAMIEN , MORITZ CRAIG , FITZSIMMONS NANCY N. , LIMPUS COLIN J. , LAVERY SHANE , WHITING SCOTT , GUINEA MICK , PRINCE ROBERT I. T. , KENNETT ROD 
Published: August 2006

AbstractEcological and genetic studies of marine turtles generally support the hypothesis of natal homing, but leave open the question of the geographical scale of genetic exchange and the capacity of turtles to shift breeding sites. Here we combine analyses of mitochondrial DNA (mtDNA) variation and recapture data to assess the geographical scale of individual breeding populations and the distribution of such populations through Australasia. We conducted multiscale assessments of mtDNA variation among 714 samples from 27 green turtle rookeries and of adult female dispersal among nesting sites in eastern Australia. Many of these rookeries are on shelves that were flooded by rising sea levels less than 10 000 years (c. 450 generations) ago. Analyses of sequence variation among the mtDNA control region revealed 25 haplotypes, and their frequency distributions indicated 17 genetically distinct breeding stocks (Management Units) consisting either of individual rookeries or groups of rookeries in general that are separated by more than 500 km. The population structure inferred from mtDNA was consistent with the scale of movements observed in long‐term mark–recapture studies of east Australian rookeries. Phylogenetic analysis of the haplotypes revealed five clades with significant partitioning of sequence diversity (Φ = 68.4) between Pacific Ocean and Southeast Asian/Indian Ocean rookeries. Isolation by distance was indicated for rookeries separated by up to 2000 km but explained only 12% of the genetic structure. The emerging general picture is one of dynamic population structure influenced by the capacity of females to relocate among proximal breeding sites, although this may be conditional on large population sizes as existed historically across this region.
The Arabidopsis thaliana/Myzus persicae model system demonstrates that a single gene can influence the interaction between a plant and a sap‐feeding insect
Authors: HUNT E. J. , PRITCHARD J. , BENNETT M. J. , ZHU X. , BARRETT D. A. , ALLEN T. , BALE JS , NEWBURY H. J. 
Published: August 2006

AbstractWe have developed an Arabidopsis thaliana/Myzus persicae model system to allow the dissection of plant/insect interactions at a molecular genetic level. This allows the examination of the role of single plant genes in the interaction between the plant and an aphid. Our initial studies have exploited an Arabidopsis genotype in which the function of the amino acid transporter ANT1 has been abolished. This mutation results in a change in the proportions of several amino acids within the phloem sieve elements (SEs) resulting in an increase in the proportion of essential amino acids. This has been measured using aphid stylectomy to collect SE samples, followed by a novel micellar electrokinetic chromatography method for amino acid analysis. The SE content represents the aphid's diet, and use of electrical penetration graph technology and honeydew clocks have demonstrated that this altered diet results in a change in the feeding rate of the aphid. Balance sheets can be produced to show the amount (nmoles/24 h) of each of 18 amino acids taken up and excreted by aphids feeding on wild type and ant1 mutant plants. The data show that aphids feeding on the ant1 mutant take up larger amounts of amino acids. However, we could not detect any effect on the reproductive rate of the aphids. The results show that, under experimental conditions, this model system can be used to identify plant genes that control the behaviour and fecundity of an insect pest.
Inbreeding depression and multiple regions showing heterozygote advantage in Drosophila melanogaster exposed to stress
Authors: FERREIRA ÁLVARO G. A. , AMOS WILLIAM 
Published: August 2006

AbstractRecent studies that reveal a correlation between heterozygosity and fitness in natural populations have rekindled interest in whether balancing selection is widespread or an evolutionary oddity. We therefore quantified heterozygote advantage at 12 microsatellite markers in both inbred and outbred crosses of Drosophila grown under different forms of environmental stress. As expected, inbreeding depression reduces fitness relative to the outbred controls. In addition, many loci exhibit heterozygote advantage over and above any effect due to inbreeding, with ∼30% of markers showing an effect in any given culture condition and ∼75% of markers showing an effect in at least one of the four culture conditions. To explore the extent of linkage disequilibrium surrounding these loci we further typed four new markers close to each of the three strongest hits. We find a pattern where the extent of heterozygote excess tends to decline to nonsignificance within around 1.5 megabases (Mb) either side of the original hit. Crude extrapolation suggests 12 genes or regions experience detectable levels of heterozygote advantage in any one condition and as many as 25 overall. Thus, balancing selection is widespread and is likely to play an important role in maintaining genetic variability.
Understanding the shapes of bacteria just got more complicated
Authors: Beveridge Terry J. 
Published: August 2006

SummaryThe paper by Briegel et al. in this issue of Molecular Microbiology uses advanced cryo‐transmission electron microscopy (cryoTEM) techniques to reveal four separate locations of cytoplasmic filament bundles in Caulobacter crescentus. Intuitively, these filaments should be rather rigid protein structures and composed of previously identified shape‐forming proteins, such as crescentin or MreB. Yet, deletion mutants lacking these proteins still possessed filaments and still possessed wild‐type morphology. These results suggest that a complex combination of protein structures, including those of crescentin, MreB and these newly identified bundles, in combination with the cell envelope help maintain the complicated shape of C. crescentus. Other bacteria might have similar architectural proteins to assist in maintaining the cell contours during growth and division.
Molecular genotyping to distinguish between recrudescents and new infections in treatment trials of Plasmodium falciparum malaria conducted in Sub‐Saharan Africa: adjustment of parasitological outcomes and assessment of genotyping effectiveness
Authors: Mugittu Kefas , Adjuik Martin , Snounou Georges , Ntoumi Francine , Taylor Walter , Mshinda Hassan , Olliaro Piero , Beck Hans‐Peter 
Published: August 2006

SummaryMolecular genotyping of baseline and post‐treatment recurrent Plasmodium falciparum is recommended to distinguish recrudescent from new infections. However, genotyping performance and adjustment of treatment outcomes have not been evaluated in large field trials. Parasitological outcomes were assessed in nine double‐blinded trials of uncomplicated P. falciparum malaria in African children treated with artesunate/placebo plus standard monotherapies. Day 28 failure rates were adjusted by stepwise genotyping the P. falciparum glutamate rich protein (glurp), merozoite surface protein 1 (msp1) and 2 (msp2). We calculated overall and laboratory genotyping performance and compared unadjusted (crude) and PCR‐adjusted outcomes. 3455 (93.6%) of 3691 enrolled patients were evaluable by Day 28. 767 (22%) had post‐Day 14 recurrent parasitemias of which 686 could be genotyped: 246 were recrudescences, 286 new infections and 154 unresolved. The overall and laboratory genotyping performance were 69 (12–100)% and 78 (50–100)%, respectively. The mean Day 28 crude parasitological failure rate was 44 (range 3–87)%. PCR‐adjusted rates were 36 (range 2–86)% if unresolved infections were counted as failures or 33 (range 2–86)% if excluded from analysis. The overall difference between crude Day 28 and Day 14 failure rates was 22% (95% CI 20.3, 24.6) but decreased to 14% (95% CI 12.1, 16.3) if unresolved infections are counted as failures, or to 11% (95% CI 9.8, 16.3) if unresolved infections are excluded from the analysis. Genotyping refined treatment outcomes but diligence is needed in sample collection and analysis to improve its performance. Our findings support the WHO recommendation of PCR genotyping in malaria clinical trials and suggest that stepwise genotyping of only two loci (msp2 and msp1 or glurp) can reliably discriminate recrudescences from new infections.
Surveillance of the efficacy of artesunate and mefloquine combination for the treatment of uncomplicated falciparum malaria in Cambodia
Authors: Denis Mey Bouth , Tsuyuoka Reiko , Poravuth Yi , Narann Top Sophoan , Seila Suon , Lim Chim , Incardona Sandra , Lim Pharath , Sem Rithy , Socheat Duong , Christophel Eva Maria , Ringwald Pascal 
Published: August 2006

SummaryArtesunate and mefloquine combination treatment has been used since 2000 in Cambodia as the first‐line drug for the treatment of uncomplicated falciparum malaria. In order to assess its efficacy and safety, the national malaria control programme conducted 14 therapeutic efficacy studies with the drug combination between 2001 and 2004 at nine sites. In 2001 and 2002, co‐blister packs of artesunate and mefloquine were used, whereas in 2003 and 2004, drugs were given individually from a bulk pack at a total dose of 12 mg/kg of artesunate and 25 mg/kg of mefloquine over 3 days. A total of 1025 patients were enrolled over the 4 years and 977 were follow‐up during the period of 28 days. The PCR‐corrected cure rates ranged from 85.7% to 100% with an overall cure rate of 95.8% (920/960). The studies in 2002 showed also that co‐blister packs used on the basis of age and not on the basis of weight could lead to underdosed regimens but without any detectable effect on the treatment outcome. The follow‐up period was extended from 28 to 42 days in three sites in 2004. A total of 219 among 255 were follow‐up until day 42. The cure rate decreased but not significantly from 90.1% (73/81) with 28 days follow‐up to 79.3% (46/58) with 42 days follow‐up in Pailin, whereas the cure rate remained at 100% in the two other sites. Side effects were common, especially dizziness, but were mild and transient and patients recovered without any medical intervention.
The evolution of trans‐generational altruism: kin selection meets niche construction
Authors: LEHMANN L. 
Published: August 2006

AbstractA cornerstone result of sociobiology states that limited dispersal can induce kin competition to offset the kin selected benefits of altruism. Several mechanisms have been proposed to circumvent this dilemma but all assume that actors and recipients of altruism interact during the same time period. Here, this assumption is relaxed and a model is developed where individuals express an altruistic act, which results in posthumously helping relatives living in the future. The analysis of this model suggests that kin selected benefits can then feedback on the evolution of the trait in a way that promotes altruistic helping at high rates under limited dispersal. The decoupling of kin competition and kin selected benefits results from the fact that by helping relatives living in the future, an actor is helping individuals that are not in direct competition with itself. A direct consequence is that behaviours which actors gain by reducing the common good of present and future generations can be opposed by kin selection. The present model integrates niche‐constructing traits with kin selection theory and delineates demographic and ecological conditions under which altruism can be selected for; and conditions where the ‘tragedy of the commons’ can be reduced.
Effects of B chromosomes and supernumerary segments on morphometric traits and adult fitness components in the grasshopper, Dichroplus elongatus (Acrididae)
Authors: ROSETTI N. , VILARDI J. C. , REMIS M. I. 
Published: August 2006

AbstractThe South American species, Dichroplus elongatus, is polymorphic for B chromosomes and supernumerary segments in chromosome pairs M6 (SS6), S9 (SS9) and S10 (SS10). Both forms of supernumerary heterochromatin shape chiasma frequency and distribution and B chromosomes also affect male fertility. Here, we analysed the effects of these polymorphisms on morphometric traits (total, 3rd femur, 3rd tibia, thorax and tegmen lengths) and several adult fitness components, including male and female mating success, and female reproductive potential. B chromosomes tend to decrease, and SS6 segments to increase the body size of carriers. The analysis of reproductive potential suggested that B chromosome carrying females have higher numbers of embryos per clutch and ovarioles per ovary. The uni‐ and multivariate analysis of mating success revealed that sexual selection favours larger individuals of both sexes and males with standard karyotype. B chromosomes may have accumulation mechanisms, which involve preferential transmission of B chromosomes to germ cells or functional gametes. The maintenance of Bs might be explained by interactions among accumulation mechanisms and trade‐offs between detrimental and favourable effects on different fitness components.
Changed environmental conditions weaken sexual selection in sticklebacks
Authors: CANDOLIN U. , SALESTO T. , EVERS M. 
Published: August 2006

AbstractEnvironmental heterogeneity can cause the intensity and direction of selection to vary in time and space. Yet, the effects of human‐induced environmental changes on sexual selection and the expression of mating traits of native species are poorly known. Currently, the breeding habitats of the three‐spined sticklebackGasterosteus aculeatus are changing in the Baltic Sea because of eutrophication and increased growth of algae. Here we show that enhanced growth of filamentous algae increases the costs of mating by inducing an increase in the time and energy spent on courtship and mate choice. This is not followed by a concomitant increase in mate attraction, but instead the strength of selection on male red nuptial coloration and courtship activity is relaxed. Thus, the high investment into the costly sexually selected traits is maladaptive under the new conditions, and the mating system mediates a negative effect of the environmental change on the population. We attribute these environmentally induced changes in the benefit of the mating traits and in the strength of sexual selection to reduced visibility in dense vegetation. Anthropogenic disturbances hence affect the selection pressures that mould the species, which could have long‐term effects on the viability and evolution of the populations.
A Study of the Transfer of Tetracycline Resistance Genes Between Escherichia coli in the Intestinal Tract of a Mouse and a Chicken Model
Authors: Hart W. S. , Heuzenroeder M. W. , Barton M. D. 
Published: August 2006

SummaryExperiments to demonstrate the transfer of genes within a natural environment are technically difficult because of the unknown numbers and strains of bacteria present, as well as difficulties designing adequate control experiments. The results of such studies should be viewed within the limits of the experimental design. Most experiments to date have been based on artificial models, which only give approximations of the real‐life situation. The current study uses more natural models and provides information about tetracycline resistance as it occurs in wild‐type bacteria within the environment of the normal intestinal tract of an animal. Tetracycline sensitive, nalidixic acid resistant Escherichia coli isolates of human origin were administered to mice and chicken animal models. They were monitored for acquisition of tetracycline resistance from indigenous or administered donor E. coli. Five sets of in vivo experiments demonstrated unequivocal transfer of tetracycline resistance to tetracycline sensitive recipients. The addition of tetracycline in the drinking water of the animals increased the probability of transfer between E. coli strains originating from the same animal species. The co‐transfer of unselected antibiotic resistance in animal models was also demonstrated.