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| 2. |
- Janssen, Ralf, 1975-, et al.
(författare)
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Gene expression patterns in an onychophoran reveal that regionalization predates limb segmentation in pan-arthropods
- 2010
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Ingår i: Evolution & Development. - 1520-541X .- 1525-142X. ; 12:4, s. 363-372
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Tidskriftsartikel (refereegranskat)abstract
- In arthropods, such as Drosophila melanogaster, the leg gap genes homothorax (hth), extradenticle (exd), dachshund (dac), and Distal-less (Dll) regionalize the legs in order to facilitate the subsequent segmentation of the legs. We have isolated homologs of all four leg gap genes from the onychophoran Euperipatoides kanangrensis and have studied their expression. We show that leg regionalization takes place in the legs of onychophorans even though they represent simple and nonsegmented appendages. This implies that leg regionalization evolved for a different function and was only later co-opted for a role in leg segmentation. We also show that the leg gap gene patterns in onychophorans (especially of hth and exd) are similar to the patterns in crustaceans and insects, suggesting that this is the plesiomorphic state in arthropods. The reversed hth and exd patterns in chelicerates and myriapods are therefore an apomorphy for this group, the Myriochelata, lending support to the Myriochelata and Tetraconata clades in arthropod phylogeny.
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| 3. |
- Eriksson, Bo Joakim, et al.
(författare)
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Head patterning and Hox gene expression in an onychophoran and its implications for the arthropod head problem
- 2010
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Ingår i: Development, Genes and Evolution. - : Springer Science and Business Media LLC. - 0949-944X .- 1432-041X. ; 220:3-4, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- The arthropod head problem has puzzled zoologists for more than a century. The head of adult arthropods is a complex structure resulting from the modification, fusion and migration of an uncertain number of segments. In contrast, onychophorans, which are the probable sister group to the arthropods, have a rather simple head comprising three segments that are well defined during development, and give rise to the adult head with three pairs of appendages specialised for sensory and food capture/manipulative purposes. Based on the expression pattern of the anterior Hox genes labial, proboscipedia, Hox3 and Deformed, we show that the third of these onychophoran segments, bearing the slime papillae, can be correlated to the tritocerebrum, the most anterior Hox-expressing arthropod segment. This implies that both the onychophoran antennae and jaws are derived from a more anterior, Hox-free region corresponding to the proto and deutocerebrum of arthropods. Our data provide molecular support for the proposal that the onychophoran head possesses a well-developed appendage that corresponds to the anterior, apparently appendage-less region of the arthropod head.
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| 4. |
- Janssen, H., et al.
(författare)
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Translating the use of an enriched environment poststroke from bench to bedside: study design and protocol used to test the feasibility of environmental enrichment on stroke patients in rehabilitation
- 2012
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Ingår i: International Journal of Stroke. - : SAGE Publications. - 1747-4930 .- 1747-4949. ; 7:6, s. 521-526
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Tidskriftsartikel (refereegranskat)abstract
- Rationale Environmental enrichment, a paradigm investigated extensively in animal models, is an intervention, which by design facilitates motor, sensory, social, and cognitive activity. It has been shown to improve poststroke motor and cognitive function in animal models of stroke. This is the first study to attempt to translate this intervention from the laboratory to the clinical setting. Aims The overall aim of this pilot study is to test the feasibility of using environmental enrichment with stroke patients in a rehabilitation setting. The aim is to enrich the environment of stroke survivors in a rehabilitation ward and measure changes in their activity (physical, cognitive, and social activity). Design Prospective nonrandomized block design intervention study. Study In the control phase we will determine the change in activity levels of patients treated in a usual rehabilitation environment over time. In the intervention phase structured observational techniques (behavioural mapping) will be used to quantify the change in activity levels of patients exposed to environmental enrichment. Outcomes The primary outcome is change in activity level. Additional data collected on entry to and exit from the study will include: cognitive function using a battery of cognitive tests, general function using the Functional Independence Measure, mood using the Patient Health Questionnaire 9 and boredom using the Stroke Rehabilitation Boredom Survey. Quality of life will be assessed using the Assessment of Quality of Life 1 month postdischarge from rehabilitation. Australian New Zealand Clinical Trials Registry# ACTRN12611000629932.
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| 5. |
- Janssen, Ralf, et al.
(författare)
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Conservation, loss, and redeployment of Wnt ligands in protostomes : implications for understanding the evolution of segment formation
- 2010
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 10, s. 374-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Wnt genes encode secreted glycoprotein ligands that regulate a wide range of developmental processes, including axis elongation and segmentation. There are thirteen subfamilies of Wnt genes in metazoans and this gene diversity appeared early in animal evolution. The loss of Wnt subfamilies appears to be common in insects, but little is known about the Wnt repertoire in other arthropods, and moreover the expression and function of these genes have only been investigated in a few protostomes outside the relatively Wnt-poor model species Drosophila melanogaster and Caenorhabditis elegans. To investigate the evolution of this important gene family more broadly in protostomes, we surveyed the Wnt gene diversity in the crustacean Daphnia pulex, the chelicerates Ixodes scapularis and Achaearanea tepidariorum, the myriapod Glomeris marginata and the annelid Platynereis dumerilii. We also characterised Wnt gene expression in the latter three species, and further investigated expression of these genes in the beetle Tribolium castaneum. Results: We found that Daphnia and Platynereis both contain twelve Wnt subfamilies demonstrating that the common ancestors of arthropods, ecdysozoans and protostomes possessed all members of all Wnt subfamilies except Wnt3. Furthermore, although there is striking loss of Wnt genes in insects, other arthropods have maintained greater Wnt gene diversity. The expression of many Wnt genes overlap in segmentally reiterated patterns and in the segment addition zone, and while these patterns can be relatively conserved among arthropods and the annelid, there have also been changes in the expression of some Wnt genes in the course of protostome evolution. Nevertheless, our results strongly support the parasegment as the primary segmental unit in arthropods, and suggest further similarities between segmental and parasegmental regulation by Wnt genes in annelids and arthropods respectively. Conclusions: Despite frequent losses of Wnt gene subfamilies in lineages such as insects, nematodes and leeches, most protostomes have probably maintained much of their ancestral repertoire of twelve Wnt genes. The maintenance of a large set of these ligands could be in part due to their combinatorial activity in various tissues.
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| 6. |
- Janssen, Ralf, 1975-, et al.
(författare)
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Expression of myriapod pair rule gene orthologs
- 2011
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Ingår i: EvoDevo. - : Springer Science and Business Media LLC. - 2041-9139. ; 2:5
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundSegmentation is a hallmark of the arthropods; most knowledge about the molecular basis of arthropod segmentation comes from work on the fly Drosophila melanogaster. In this species a hierarchic cascade of segmentation genes subdivides the blastoderm stepwise into single segment wide regions. However, segmentation in the fly is a derived feature since all segments form virtually simultaneously. Conversely, in the vast majority of arthropods the posterior segments form one at a time from a posterior pre-segmental zone. The pair rule genes (PRGs) comprise an important level of the Drosophila segmentation gene cascade and are indeed the first genes that are expressed in typical transverse stripes in the early embryo. Information on expression and function of PRGs outside the insects, however, is scarce.ResultsHere we present the expression of the pair rule gene orthologs in the pill millipede Glomeris marginata (Myriapoda: Diplopoda). We find evidence that these genes are involved in segmentation and that components of the hierarchic interaction of the gene network as found in insects may be conserved. We further provide evidence that segments are formed in a single-segment periodicity rather than in pairs of two like in another myriapod, the centipede Strigamia maritima. Finally we show that decoupling of dorsal and ventral segmentation in Glomeris appears already at the level of the PRGs.ConclusionsAlthough the pair rule gene network is partially conserved among insects and myriapods, some aspects of PRG interaction are, as suggested by expression pattern analysis, convergent, even within the Myriapoda. Conserved expression patterns of PRGs in insects and myriapods, however, may represent ancestral features involved in segmenting the arthropod ancestor.
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| 7. |
- Persson Waye, Kerstin, 1959, et al.
(författare)
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Rail freight vibration impacts sleep and community response: An overview of CargoVibes
- 2014
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Ingår i: ICBEN 2014, the 11th International Congress on Noise as a Public Health Problem. Nara, Japan, 2014 June 1 to June 5.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The European Union funded CargoVibes project involving 10 partners from 8 nations has aimed to examine ground-borne vibration affecting residents close to freight railway lines. This poster presents an overview of the work package investigating human response to vibration, with particular focus on physiological and psychological impact on sleep, community annoyance and the development of guidance in evaluating response. The effects of vibration on sleep were measured in a series of laboratory trials at the University of Gothenburg. Existing field studies of community response were supplemented with further field work in the Netherlands and Poland, and a meta-analysis conducted to determine dose-response relationships for railway vibration. Numerous outcomes of vibration exposure were found, with physiological markers such as greater heart rate response and cortical reactions during sleep, and annoyance and sleep disturbance increasing with higher vibration amplitudes. A guidance document considering current state of the art regarding vibration measurement and assessment was produced pertaining to human perception, evaluation methods, annoyance, sleep impacts, and non-exposure factors. The outcomes of this work represent a significant advance in the understanding of the human response to railway vibration and a step towards a much needed harmonisation of assessment methods. The findings presented in this poster highlight the importance of considering environmental vibration in the planning, construction, and maintenance of railways in residential environments.
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| 8. |
- Richards, Stephen, et al.
(författare)
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Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Tidskriftsartikel (refereegranskat)abstract
- Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
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