20‐hydroxyecdysone stimulates proliferation of glial cells in the developing brain of the moth <i>Manduca sexta</i>

Kirschenbaum, Sheila R.; Higgins, Mark R.; Tveten, Michael; Tolbert, Leslie P.

doi:10.1002/neu.480280209

Cited by 24 publications

(16 citation statements)

References 43 publications

(46 reference statements)

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“…In non-diapausing pupae, ecdysteroid levels begin to rise during the initial 4 days of adult development and continue to rise to around 40% of adult development when they begin to decline until adult emergence [53], [54]. In the M. sexta olfactory system, rising ecdysteroids influence proliferation of glial cells associating with olfactory lobe neuropile, but not neurite outgrowth of olfactory lobe neurons [55], [56]; falling ecdysteroids stimulate expression of odorant binding proteins in the antenna [38]. To test whether the previously described mitotic activity is ecdysteroid sensitive, tissue from normally developing animals (i.e.…”

Section: Resultsmentioning

confidence: 99%

Sensory Cell Proliferation within the Olfactory Epithelium of Developing Adult Manduca sexta (Lepidoptera)

et al. 2007

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BackgroundInsects detect a multitude of odors using a broad array of phenotypically distinct olfactory organs referred to as olfactory sensilla. Each sensillum contains one to several sensory neurons and at least three support cells; these cells arise from mitotic activities from one or a small group of defined precursor cells. Sensilla phenotypes are defined by distinct morphologies, and specificities to specific odors; these are the consequence of developmental programs expressed by associated neurons and support cells, and by selection and expression of subpopulations of olfactory genes encoding such proteins as odor receptors, odorant binding proteins, and odor degrading enzymes.Methodology/Principal FindingsWe are investigating development of the olfactory epithelium of adult M. sexta, identifying events which might establish sensilla phenotypes. In the present study, antennal tissue was examined during the first three days of an 18 day development, a period when sensory mitotic activity was previously reported to occur. Each antenna develops as a cylinder with an outward facing sensory epithelium divided into approximately 80 repeat units or annuli. Mitotic proliferation of sensory cells initiated about 20–24 hrs after pupation (a.p.), in pre-existing zones of high density cells lining the proximal and distal borders of each annulus. These high density zones were observed as early as two hr. a.p., and expanded with mitotic activity to fill the mid-annular regions by about 72 hrs a.p. Mitotic activity initiated at a low rate, increasing dramatically after 40–48 hrs a.p.; this activity was enhanced by ecdysteroids, but did not occur in animals entering pupal diapause (which is also ecdysteroid sensitive).Conclusions/SignificanceSensory proliferation initiates in narrow zones along the proximal and distal borders of each annulus; these zones rapidly expand to fill the mid-annular regions. These zones exist prior to any mitotic activity as regions of high density cells which form either at or prior to pupation. Mitotic sensitivity to ecdysteroids may be a regulatory mechanism coordinating olfactory development with the developmental choice of diapause entry.

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Section: Resultsmentioning

confidence: 99%

Sensory Cell Proliferation within the Olfactory Epithelium of Developing Adult Manduca sexta (Lepidoptera)

et al. 2007

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“…The main cell division site in this pupal stage occurs in the concentric regions in the corpora pedunculata calyx (Soares and Serrão, 2001a;2001b), observed anatomically as small folds in the brain apex (Fig 9). In several insects, neural accommodation occurs by death of nervous cells and glial cells (Cantera, 1993;Kirschenbaum et al, 1995;Sonnenfield and Jacobs, 1995) being suggested the role of juvenile hormone and ecdysteroid in the regulation of this process (Cayre et al, 1994;Restifo et al, 1995). In holometabolous, in the absence of juvenile hormone, ecdysteroid level in haemolymph increase, starting the pupal program.…”

Section: C) Concluding Remarksmentioning

confidence: 99%

Neuropile organization in the brain of Acromyrmex (Hymenoptera, Formicidae) during the post-embryonic development

Soares

Delabie

Serrão

2004

Braz. arch. biol. technol.

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Neuropile is the region of the central nervous system where the synapses an d neurons branching occur. During the development of an holometabolous insect can occurs break of the neurons fibers forming new axon and dendrites and their distribution in brain neuropile is organized so as to reflect specific nervous functions of adult insects. The components of this organization were observed and discussed in this study in the ant

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“…At the ultrastructural level, glial cell features were similar to those seen in normal lobes (not shown), including in-folded nuclei and cytoplasm with large amounts of glycogen or free ribosomes as well as rough endoplasmic reticulum (Tolbert and Hildebrand, 1981). The pattern of BrdU labeling among glial cells associated with the neuropil was consistent with that seen in normal stage-5 lobes (Oland and Tolbert, 1989;Kirschenbaum et al, 1995) [ Fig. 2(F)].…”

Section: Responses Of Orn Axons To Target and Nontarget Regions Of Thmentioning

confidence: 50%

A diffusible signal attracts olfactory sensory axons toward their target in the developing brain of the moth

Oland¹,

Pott²,

Howard³

et al. 2003

J. Neurobiol.

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The signals that olfactory receptor axons use to navigate to their target in the CNS are still not well understood. In the moth Manduca sexta, the primary olfactory pathway develops postembryonically, and the receptor axons navigate from an experimentally accessible sensory epithelium to the brain along a pathway long enough for detailed study of regions in which axon behavior changes. The current experiments ask whether diffusible factors contribute to receptor axon guidance. Explants were made from the antennal receptor epithelium and co-cultured in a collagen gel matrix with slices of various regions of the brain. Receptor axons were attracted toward the central regions of the brain, including the protocerebrum and antennal lobe. Receptor axons growing into a slice of the most proximal region of the antennal nerve, where axon sorting normally occurs, showed no directional preference. When the antennal lobe was included in the slice, the receptor axons entering the sorting region grew directly toward the antennal lobe. Taken together with the previous in vivo experiments, the current results suggest that an attractive diffusible factor can serve as one cue to direct misrouted olfactory receptor axons toward the medial regions of the brain, where local cues guide them to the antennal lobe. They also suggest that under normal circumstances, in which the receptor axons follow a pre-existing pupal nerve to the antennal lobe, the diffusible factor emanating from the lobe acts in parallel and at short range to maintain the fidelity of the path into the antennal lobe.

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20‐hydroxyecdysone stimulates proliferation of glial cells in the developing brain of the moth Manduca sexta

Cited by 24 publications

References 43 publications

Sensory Cell Proliferation within the Olfactory Epithelium of Developing Adult Manduca sexta (Lepidoptera)

Sensory Cell Proliferation within the Olfactory Epithelium of Developing Adult Manduca sexta (Lepidoptera)

Neuropile organization in the brain of Acromyrmex (Hymenoptera, Formicidae) during the post-embryonic development

A diffusible signal attracts olfactory sensory axons toward their target in the developing brain of the moth

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