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41.
Evolution of eye morphology and rhodopsin expression in the Drosophila melanogaster species subgroup
Posnien N Hopfen C Hilbrant M Ramos-Womack M Murat S Schönauer A Herbert SL Nunes MD Arif S Breuker CJ Schlötterer C Mitteroecker P McGregor AP 《PloS one》2012,7(5):e37346
A striking diversity of compound eye size and shape has evolved among insects. The number of ommatidia and their size are major determinants of the visual sensitivity and acuity of the compound eye. Each ommatidium is composed of eight photoreceptor cells that facilitate the discrimination of different colours via the expression of various light sensitive Rhodopsin proteins. It follows that variation in eye size, shape, and opsin composition is likely to directly influence vision. We analyzed variation in these three traits in D. melanogaster, D. simulans and D. mauritiana. We show that D. mauritiana generally has larger eyes than its sibling species, which is due to a combination of larger ommatidia and more ommatidia. In addition, intra- and inter-specific differences in eye size among D. simulans and D. melanogaster strains are mainly caused by variation in ommatidia number. By applying a geometric morphometrics approach to assess whether the formation of larger eyes influences other parts of the head capsule, we found that an increase in eye size is associated with a reduction in the adjacent face cuticle. Our shape analysis also demonstrates that D. mauritiana eyes are specifically enlarged in the dorsal region. Intriguingly, this dorsal enlargement is associated with enhanced expression of rhodopsin 3 in D. mauritiana. In summary, our data suggests that the morphology and functional properties of the compound eyes vary considerably within and among these closely related Drosophila species and may be part of coordinated morphological changes affecting the head capsule. 相似文献
42.
Maarten van den Berge Wim CJ Hop Thys van der Molen Jan A van Noord Jacques PHM Creemers Ad JM Schreurs Emiel FM Wouters Dirkje S Postma 《Respiratory research》2012,13(1):44
Background
Frequent exacerbations induce a high burden to Chronic Obstructive Pulmonary Disease (COPD). We investigated the course of exacerbations in the published COSMIC study that investigated the effects of 1-year withdrawal of fluticasone after a 3-month run-in treatment period with salmeterol/fluticasone in patients with COPD.Methods
In 373 patients, we evaluated diary cards for symptoms, Peak Expiratory Flow (PEF), and salbutamol use and assessed their course during exacerbations.Results
There were 492 exacerbations in 224 patients. The level of symptoms of cough, sputum, dyspnea and nocturnal awakening steadily increased from 2 weeks prior to exacerbation, with a sharp rise during the last week. Symptoms of cough, sputum, and dyspnea reverted to baseline values at different rates (after 4, 4, and 7 weeks respectively), whereas symptoms of nocturnal awakening were still increased after eight weeks. The course of symptoms was similar around a first and second exacerbation. Increases in symptoms and salbutamol use and decreases in PEF were associated with a higher risk to develop an exacerbation, but with moderate predictive values, the areas under the receiver operating curves ranging from 0.63 to 0.70.Conclusions
Exacerbations of COPD are associated with increased symptoms that persist for weeks and the course is very similar between a first and second exacerbation. COPD exacerbations are preceded by increased symptoms and salbutamol use and lower PEF, yet predictive values are too low to warrant daily use in clinical practice. 相似文献43.
Lonneke Smeding Frans B Pl?tz Regis R Lamberts Willem J van der Laarse Martin CJ Kneyber AB Johan Groeneveld 《Respiratory research》2012,13(1):23
Background
Injurious mechanical ventilation (MV) may augment organ injury remote from the lungs. During sepsis, myocardial dysfunction is common and increased endothelial activation and permeability can cause myocardial edema, which may, among other factors, hamper myocardial function. We investigated the effects of MV with injuriously high tidal volumes on the myocardium in an animal model of sepsis.Methods
Normal rats and intraperitoneal (i.p.) lipopolysaccharide (LPS)-treated rats were ventilated with low (6 ml/kg) and high (19 ml/kg) tidal volumes (Vt) under general anesthesia. Non-ventilated animals served as controls. Mean arterial pressure (MAP), central venous pressure (CVP), cardiac output (CO) and pulmonary plateau pressure (Pplat) were measured. Ex vivo myocardial function was measured in isolated Langendorff-perfused hearts. Cardiac expression of endothelial vascular cell adhesion molecule (VCAM)-1 and edema were measured to evaluate endothelial inflammation and leakage.Results
MAP decreased after LPS-treatment and Vt-dependently, both independent of each other and with interaction. MV Vt-dependently increased CVP and Pplat and decreased CO. LPS-induced peritonitis decreased myocardial function ex vivo but MV attenuated systolic dysfunction Vt-dependently. Cardiac endothelial VCAM-1 expression was increased by LPS treatment independent of MV. Cardiac edema was lowered Vt-dependently by MV, particularly after LPS, and correlated inversely with systolic myocardial function parameters ex vivo.Conclusion
MV attenuated LPS-induced systolic myocardial dysfunction in a Vt-dependent manner. This was associated with a reduction in cardiac edema following a lower transmural coronary venous outflow pressure during LPS-induced coronary inflammation. 相似文献44.
Population history and life history influence the migration rate of female Glanville fritillary butterflies 总被引:4,自引:0,他引:4
Ilkka Hanski Casper J. Breuker Katrin Schps Rosemary Setchfield Marko Nieminen 《Oikos》2002,98(1):87-97
This study examines the causes of emigration from small fragments of suitable habitat in a species that has a distinct metapopulation structure, frequent turnover of local populations, and substantial migration among local populations and currently unoccupied habitat fragments. We conducted a field experiment in which 727 individuals of the Glanville fritillary butterfly ( Melitaea cinxia ) originating from four regions were marked and released simultaneously in a natural environment. In three of the four source regions, larvae for the experiment were collected from dozens of small local populations, some of which had been established in the previous summer (new populations), whereas the remaining populations were older. In two of the source regions, female butterflies prefer a host plant ( Veronica spicata ) that is not present in the release area, where there is only Plantago lanceolata , the preferred host plant of females from the other two source regions. We found that migration rate of males was unrelated to any of the factors studied in this experiment. In contrast, two factors influenced the migration rate of females. First, Veronica -preferring females had higher emigration rate than Plantago- preferring females from the Plantago -containing release patches, demonstrating that the individual perception of habitat quality significantly influences the migration rate of females. Second, females from newly-established populations were more dispersive than females from older populations, supporting the notion that metapopulation processes (recurrent colonizations) select for increased migration. The observed migration rate was not correlated with any body size measurements, and thus the observed differences in migration rate were apparently caused by differences in the behaviour of female butterflies rather than in their flight capacity. 相似文献
45.
46.
A covariotide model explains apparent phylogenetic structure of oxygenic photosynthetic lineages 总被引:17,自引:13,他引:4
Lockhart PJ; Steel MA; Barbrook AC; Huson DH; Charleston MA; Howe CJ 《Molecular biology and evolution》1998,15(9):1183-1188
The aims of the work were (1) to develop statistical tests to identify
whether substitution takes place under a covariotide model in sequences
used for phylogenetic inference and (2) to determine the influence of
covariotide substitution on phylogenetic trees inferred for photosynthetic
and other organisms. (Covariotide and covarion models are ones in which
sites that are variable in some parts of the underlying tree are invariable
in others and vice versa.) Two tests were developed. The first was a
contingency test, and the second was an inequality test comparing the
expected number of variable sites in two groups with the observed number.
Application of these tests to 16S rDNA and tufA sequences from a range of
nonphotosynthetic prokaryotes and oxygenic photosynthetic prokaryotes and
eukaryotes suggests the occurrence of a covariotide mechanism. The degree
of support for partitioning of taxa in reconstructed trees involving these
organisms was determined in the presence or absence of sites showing
particular substitution patterns. This analysis showed that the support for
splits between (1) photosynthetic eukaryotes and prokaryotes and (2)
photosynthetic and nonphotosynthetic organisms could be accounted for by
patterns arising from covariotide substitution. We show that the additional
problem of compositional bias in sequence data needs to be considered in
the context of patterns of covariotide/covarion substitution. We argue that
while covariotide or covarion substitution may give rise to
phylogenetically informative patterns in sequence data, this may not always
be so.
相似文献
47.
Using ontologies to describe mouse phenotypes 总被引:1,自引:1,他引:0
The mouse is an important model of human genetic disease. Describing phenotypes of mutant mice in a standard, structured manner that will facilitate data mining is a major challenge for bioinformatics. Here we describe a novel, compositional approach to this problem which combines core ontologies from a variety of sources. This produces a framework with greater flexibility, power and economy than previous approaches. We discuss some of the issues this approach raises. 相似文献
48.
Olfactory sensitivity in tsetse flies: a daily rhythm 总被引:3,自引:0,他引:3
The diurnal tsetse Glossina morsitans morsitans bites especially in early
morning and late afternoon; around midday feeding is at a low. In
laboratory apparatus that measures the amount of locomotion under constant
conditions over the photophase, the flies display a similar patterning of
activity levels. The profile of daily rhythms for G. morsitans reported in
the literature includes a number of motor and sensory motor systems that
fluctuate cophasically. Lacking is a study on the patterning of the senses'
response levels. In this paper we present the first instance of a daily
modulation in the sense of smell. We stimulated the antennae with
concentration series of host-derived odours and measured the spiking rate
of cells at different times during the photophase. The
concentration-response curves suggest that the sensitivity of antennal
olfactory cells flows in parallel with the other daily rhythms. This was
also reflected in electroantennograms (EAGs). The electroantennography was
extended to G. fuscipes fuscipes, whose level of spontaneous locomotor
activity--instead of following a U- shaped pattern--rises gradually over
the photophase. Again, the EAGs appeared to parallel the species' locomotor
activity. What we believe happens is that the organism tones down the
sensitivity of its odour receptors during periods of anticipated inactivity
for reasons of economy.
相似文献
49.
Laura Ferguson Ferdinand Marlétaz Jean-Michel Carter William R. Taylor Melanie Gibbs Casper J. Breuker Peter W. H. Holland 《PLoS genetics》2014,10(10)
Gene duplications within the conserved Hox cluster are rare in animal evolution, but in Lepidoptera an array of divergent Hox-related genes (Shx genes) has been reported between pb and zen. Here, we use genome sequencing of five lepidopteran species (Polygonia c-album, Pararge aegeria, Callimorpha dominula, Cameraria ohridella, Hepialus sylvina) plus a caddisfly outgroup (Glyphotaelius pellucidus) to trace the evolution of the lepidopteran Shx genes. We demonstrate that Shx genes originated by tandem duplication of zen early in the evolution of large clade Ditrysia; Shx are not found in a caddisfly and a member of the basally diverging Hepialidae (swift moths). Four distinct Shx genes were generated early in ditrysian evolution, and were stably retained in all descendent Lepidoptera except the silkmoth which has additional duplications. Despite extensive sequence divergence, molecular modelling indicates that all four Shx genes have the potential to encode stable homeodomains. The four Shx genes have distinct spatiotemporal expression patterns in early development of the Speckled Wood butterfly (Pararge aegeria), with ShxC demarcating the future sites of extraembryonic tissue formation via strikingly localised maternal RNA in the oocyte. All four genes are also expressed in presumptive serosal cells, prior to the onset of zen expression. Lepidopteran Shx genes represent an unusual example of Hox cluster expansion and integration of novel genes into ancient developmental regulatory networks. 相似文献
50.
Since the publication of our article (Roth, Gonnet, and Dessimoz: BMC Bioinformatics 2008 9: 518), we have noticed several errors, which we correct in the following. 相似文献