Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Morphologican and functional studies on the Drosophila neuromuscular system during postembryonic stages
Stockholm University, Faculty of Science, Department of Zoology.
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The nervous system of the fruit fly Drosophila melanogaster has emerged as an excellent model for fundamental neuroscience as well as for biomedical research of human neurological diseases. In this thesis, two aspects of the neuromuscular system have been investigated: the role of the IkB-protein Cactus in the larval neuromuscular junction and the morphology of motor terminals throughout adult life.

We found that cactus mutant larvae have poor locomotion, morphological abnormalities at the presynaptic site of motor terminals and impaired mechanical and electrophysiological properties, demonstrating that Cactus is clearly involved in the normal functioning of Drosophila neuromuscular system. In the adult, we show that cactus, dorsal and dif are expressed in the brain but are not redistributed between cytoplasm and nucleus in a circadian manner as expected from a previous finding in larval brain. Both Cactus and Dif immunoreactivity was strong in mushroom bodies and antennal lobes, suggesting a putative role in olfactory memory. In the rat, proteins of the same family are involved in the regulation of sleep but we found no indication of such regulation in flies subjected to 6 hrs of sleep deprivation.

We found that neuromuscular junctions continue to change throughout adult life. Two types of long-term changes in the morphology of neuromuscular junctions are demonstrated here: a daily change in the size of synaptic boutons and long-term changes in bouton size developing over several weeks. By careful morphological studies of flight neuromuscular terminals in clock-gene mutants and wild type flies of different ages we demonstrate that the daily changes depend on the biological clock and disappear in the old fly. Moreover, we show that light is necessary for the motor neurons studied to reach maximum size of synaptic boutons. Lastly, we found that the two clock genes period and timeless are also necessary to control axonal branching.

Transmission electron microscopy revealed several ultrastructural features distinct of the aging fly and indicative of reduced plasticity. We used a temperature-sensitive allele of shibire that rapidly and reversibly blocks vesicle recycling to investigate whether the morphological phenotype found in neuromuscular junctions of aging flies could be explained by impairment of endocytotic mechanisms. Our results show a clear reduction of the time required for complete paralysis and an increased recovery time in old flies, indicating that aging correlates with impaired endocytosis and membrane dynamics.

Place, publisher, year, edition, pages
Stockholm: Zoologiska institutionen , 2005. , 37 p.
Keyword [en]
Drosophila, neuromuscular system, Rel-proteins, fly brain, rhythmic morphology, aging,
National Category
Physiology
Identifiers
URN: urn:nbn:se:su:diva-609ISBN: 91-7155-108-5 (print)OAI: oai:DiVA.org:su-609DiVA: diva2:196019
Public defence
2005-09-23, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 8 C, Stockholm, 10:00
Opponent
Supervisors
Available from: 2005-08-23 Created: 2005-08-23Bibliographically approved
List of papers
1. The IkB-ortholog Cactus is necessary for normal neuromuscular function in Drosophila melanogaster
Open this publication in new window or tab >>The IkB-ortholog Cactus is necessary for normal neuromuscular function in Drosophila melanogaster
Show others...
2005 In: Neuroscience, ISSN 0306-4522, Vol. 134, no 2, 397-406 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:su:diva-23940 (URN)
Note
Part of urn:nbn:se:su:diva-609Available from: 2005-08-23 Created: 2005-08-23Bibliographically approved
2. Rel-protein expression in the adult brain of Drosophila
Open this publication in new window or tab >>Rel-protein expression in the adult brain of Drosophila
Manuscript (Other academic)
Identifiers
urn:nbn:se:su:diva-23941 (URN)
Note
Part of urn:nbn:se:su:diva-609Available from: 2005-08-23 Created: 2005-08-23 Last updated: 2010-01-13Bibliographically approved
3. Daily morphological changes of Drosophila motorneuron terminals
Open this publication in new window or tab >>Daily morphological changes of Drosophila motorneuron terminals
Show others...
Article in journal (Refereed) Submitted
Identifiers
urn:nbn:se:su:diva-23942 (URN)
Note
Part of urn:nbn:se:su:diva-609Available from: 2005-08-23 Created: 2005-08-23Bibliographically approved
4. Neuromuscular junction in abdominal muscles of Drosophila melanogaster during adulthood and aging
Open this publication in new window or tab >>Neuromuscular junction in abdominal muscles of Drosophila melanogaster during adulthood and aging
Show others...
2007 (English)In: Journal of Comparative Neurology, ISSN 0021-9967, E-ISSN 1096-9861, Vol. 501, no 4, 498-508 p.Article in journal (Refereed) Published
Abstract [en]

The neuromuscular junction (NMJ) of Drosophila melanogaster has been established as a productive model for the study of synaptogenesis, synaptic plasticity, vesicle recycling, and other synaptic functions in embryos and larvae. It also has potential for the study of long-term plasticity during adult life and degenerative processes associated with aging. Here we provide a detailed description of the morphology and ultrastructure of the NMJ on abdominal dorsal longitudinal muscles throughout adult life from eclosion to senescence. In contrast to the case in the larva, the predominant type of terminals in these muscles in the adult fly consists of only two or three branches with tightly packed synaptic boutons. We observed qualitative and quantitative changes as mean bouton size increased gradually during adulthood, and the largest boutons were present in the old fly. The length of nerve branches first increased and thereafter decreased gradually during most of adult life. Branch diameter also decreased progressively, but branch number did not change. The subsynaptic reticulum became progressively thinner, and “naked” boutons were found in old flies. Ultrastructural traits gave indications of an age-associated increment in autophagy, larger synaptic vesicles, and impaired endocytosis. We propose that NMJ aging in the fly correlates with impaired endocytosis and membrane dynamics. This view finds a functional correlate in flies carrying a temperature-sensitive mutation in shibire that reversible blocks endocytosis; age significantly reduces the time required for complete paralysis and increases the time of recovery, thus confirming the age-dependent alteration in vesicle dynamics.

Keyword
Drosophila melanogaster, neuromuscular junction, synaptic boutons, neurodegeneration, endocytosis, shibire
National Category
Zoology
Identifiers
urn:nbn:se:su:diva-23943 (URN)10.1002/cne.21253 (DOI)000244550400003 ()
Available from: 2005-08-23 Created: 2005-08-23 Last updated: 2017-12-13Bibliographically approved

Open Access in DiVA

No full text

By organisation
Department of Zoology
Physiology

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 154 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf