scholarly journals Anatomy of the Nervous System in Chelifer cancroides (Arachnida: Pseudoscorpiones) with a Distinct Sensory Pathway Associated with the Pedipalps

Insects ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 25
Author(s):  
Torben Stemme ◽  
Sarah E. Pfeffer
Keyword(s):  
Nervous System ◽  
Mushroom Body ◽  
Sensory Systems ◽  
Evolutionary Origin ◽  
Innervation Pattern ◽  
Sensory Organs ◽  
Functional Aspects ◽  
Sensory Pathway ◽  
Sensory Structures ◽  
Projection Pattern

Many arachnid taxa have evolved unique, highly specialized sensory structures such as antenniform legs in Amblypygi (whip spiders), for instance, or mesosomal pectines in scorpions. Knowledge of the neuroanatomy as well as functional aspects of these sensory organs is rather scarce, especially in comparison to other arthropod clades. In pseudoscorpions, no special sensory structures have been discovered so far. Nevertheless, these animals possess dominant, multifunctional pedipalps, which are good candidates for being the primary sensory appendages. However, only little is known about the anatomy of the nervous system and the projection pattern of pedipalpal afferents in this taxon. By using immunofluorescent labeling of neuronal structures as well as lipophilic dye labeling of pedipalpal pathways, we identified the arcuate body, as well as a comparatively small mushroom body, the latter showing some similarities to that of Solifugae (sun spiders and camel spiders). Furthermore, afferents from the pedipalps terminate in a glomerular and a layered neuropil. Due to the innervation pattern and structural appearance, we conclude that these neuropils are the first integration centers of the chemosensory and mechanosensory afferents. Within Arthropoda, but also other invertebrates or even vertebrates, sensory structures show rather similar neuronal arrangement. Thus, these similarities in the sensory systems of different evolutionary origin have to be interpreted as functional prerequisites of the respective modality.

Jellyfish Locomotion

2018 ◽  
Author(s):  
Richard Satterlie
Keyword(s):  
Nervous System ◽  
System Organization ◽  
The Other ◽  
Sensory Organs ◽  
Jet Propulsion ◽  
Propulsion Mechanism ◽  
Parallel Networks ◽  
Oblate Body ◽  
Sensory Structures ◽  
Marginal Integration

Two dichotomies exist within the swim systems of jellyfish—one centered on the mechanics of locomotion and the other on phylogenetic differences in nervous system organization. For example, medusae with prolate body forms use a jet propulsion mechanism, whereas medusae with oblate body forms use a drag-based marginal rowing mechanism. Independent of this dichotomy, the nervous systems of hydromedusae are very different from those of scyphomedusae and cubomedusae. In hydromedusae, marginal nerve rings contain parallel networks of neurons that include the pacemaker network for the control of swim contractions. Sensory structures are similarly distributed around the margin. In scyphomedusae and cubomedusae, the swim pacemakers are restricted to marginal integration centers called rhopalia. These ganglionlike structures house specialized sensory organs. The swim system adaptations of these three classes (Hydrozoa, Scyphozoa, and Cubozoa), which are constrained by phylogenetics, still adhere to the biomechanical efficiencies of the prolate/oblate dichotomy. This speaks to the adaptational abilities of the cnidarian nervous system as specialized in the medusoid forms.

Comparative Study of the Fine Morphology of Sensory Receptors in Aspidogaster conchicola and Cotylaspis insignis

1972 ◽  
Vol 30 ◽  
pp. 150-151
Author(s):  
Venita F. Allison ◽  
J. E. Ubelaker ◽  
J. H. Martin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nervous System ◽  
Osmic Acid ◽  
Sensory Receptors ◽  
Transmission Electron ◽  
Sensory Structures ◽  
Fine Morphology ◽  
Scanning Electron

It has been suggested that parasitism results in a reduction of sensory structures which concomitantly reflects a reduction in the complexity of the nervous system. The present study tests this hypothesis by examining the fine morphology and the distribution of sensory receptors for two species of aspidogastrid trematodes by transmission and scanning electron microscopy. The species chosen are an ectoparasite, Cotylaspis insignis and an endoparasite, Aspidogaster conchicola.Aspidogaster conchicola and Cotylaspis insignis were obtained from natural infections of clams, Anodonta corpulenta and Proptera purpurata. The specimens were fixed for transmission electron microscopy in phosphate buffered paraformaldehyde followed by osmic acid in the same buffer, dehydrated in an ascending series of ethanol solutions and embedded in Epon 812.

Vol. 3: Nervous System and Sensory Organs

2002 ◽  
Author(s):  
Werner Kahle ◽  
Michael Frotscher
Keyword(s):  
Nervous System ◽  
Sensory Organs

scholarly journals A Gain-of-Function Screen for Genes That Affect the Development of the Drosophila Adult External Sensory Organ

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 733-752 ◽  
Author(s):  
Salim Abdelilah-Seyfried ◽  
Yee-Ming Chan ◽  
Chaoyang Zeng ◽  
Nicholas J Justice ◽  
Susan Younger-Shepherd ◽  
...  
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Cell Fate ◽  
P Element ◽  
External Support ◽  
Sensory Organ ◽  
Sensory Organs ◽  
Gain Of Function ◽  
Asymmetric Cell Divisions ◽  
Single Precursor

Abstract The Drosophila adult external sensory organ, comprising a neuron and its support cells, is derived from a single precursor cell via several asymmetric cell divisions. To identify molecules involved in sensory organ development, we conducted a tissue-specific gain-of-function screen. We screened 2293 independent P-element lines established by P. Rørth and identified 105 lines, carrying insertions at 78 distinct loci, that produced misexpression phenotypes with changes in number, fate, or morphology of cells of the adult external sensory organ. On the basis of the gain-of-function phenotypes of both internal and external support cells, we subdivided the candidate lines into three classes. The first class (52 lines, 40 loci) exhibits partial or complete loss of adult external sensory organs. The second class (38 lines, 28 loci) is associated with increased numbers of entire adult external sensory organs or subsets of sensory organ cells. The third class (15 lines, 10 loci) results in potential cell fate transformations. Genetic and molecular characterization of these candidate lines reveals that some loci identified in this screen correspond to genes known to function in the formation of the peripheral nervous system, such as big brain, extra macrochaetae, and numb. Also emerging from the screen are a large group of previously uncharacterized genes and several known genes that have not yet been implicated in the development of the peripheral nervous system.

Axial specification for sensory organs versus non-sensory structures of the chicken inner ear

Development ◽  
1998 ◽  
Vol 125 (1) ◽  
pp. 11-20 ◽  
Author(s):  
D.K. Wu ◽  
F.D. Nunes ◽  
D. Choo
Keyword(s):  
Gene Expression ◽  
Inner Ear ◽  
Expression Patterns ◽  
Growth Factor Receptor ◽  
Gross Anatomy ◽  
Sensory Organ ◽  
Sensory Organs ◽  
Organ Formation ◽  
Sensory Structures ◽  
Axial Specification

A mature inner ear is a complex labyrinth containing multiple sensory organs and nonsensory structures in a fixed configuration. Any perturbation in the structure of the labyrinth will undoubtedly lead to functional deficits. Therefore, it is important to understand molecularly how and when the position of each inner ear component is determined during development. To address this issue, each axis of the otocyst (embryonic day 2.5, E2.5, stage 16–17) was changed systematically at an age when axial information of the inner ear is predicted to be fixed based on gene expression patterns. Transplanted inner ears were analyzed at E4.5 for gene expression of BMP4 (bone morphogenetic protein), SOHo-1 (sensory organ homeobox-1), Otx1 (cognate of Drosophila orthodenticle gene), p75NGFR (nerve growth factor receptor) and Msx1 (muscle segment homeobox), or at E9 for their gross anatomy and sensory organ formation. Our results showed that axial specification in the chick inner ear occurs later than expected and patterning of sensory organs in the inner ear was first specified along the anterior/posterior (A/P) axis, followed by the dorsal/ventral (D/V) axis. Whereas the A/P axis of the sensory organs was fixed at the time of transplantation, the A/P axis for most non-sensory structures was not and was able to be re-specified according to the new axial information from the host. The D/V axis for the inner ear was not fixed at the time of transplantation. The asynchronous specification of the A/P and D/V axes of the chick inner ear suggests that sensory organ formation is a multi-step phenomenon, rather than a single inductive event.

Some fly sensory organs are gliogenic and require glide/gcm in a precursor that divides symmetrically and produces glial cells

Development ◽  
2000 ◽  
Vol 127 (17) ◽  
pp. 3735-3743 ◽  
Author(s):  
V. Van De Bor ◽  
R. Walther ◽  
A. Giangrande
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Peripheral Nervous System ◽  
Glial Cell ◽  
Glial Cells ◽  
Sensory Organ ◽  
Asymmetric Distribution ◽  
Sensory Organs ◽  
The Central Nervous System ◽  
Glial Precursor

In flies, the choice between neuronal and glial fates depends on the asymmetric division of multipotent precursors, the neuroglioblast of the central nervous system and the IIb precursor of the sensory organ lineage. In the central nervous system, the choice between the two fates requires asymmetric distribution of the glial cell deficient/glial cell missing (glide/gcm) RNA in the neuroglioblast. Preferential accumulation of the transcript in one of the daughter cells results in the activation of the glial fate in that cell, which becomes a glial precursor. Here we show that glide/gcm is necessary to induce glial differentiation in the peripheral nervous system. We also present evidence that glide/gcm RNA is not necessary to induce the fate choice in the peripheral multipotent precursor. Indeed, glide/gcm RNA and protein are first detected in one daughter of IIb but not in IIb itself. Thus, glide/gcm is required in both central and peripheral glial cells, but its regulation is context dependent. Strikingly, we have found that only subsets of sensory organs are gliogenic and express glide/gcm. The ability to produce glial cells depends on fixed, lineage related, cues and not on stochastic decisions. Finally, we show that after glide/gcm expression has ceased, the IIb daughter migrates and divides symmetrically to produce several mature glial cells. Thus, the glide/gcm-expressing cell, also called the fifth cell of the sensory organ, is indeed a glial precursor. This is the first reported case of symmetric division in the sensory organ lineage. These data indicate that the organization of the fly peripheral nervous system is more complex than previously thought.

Postembryonic patterns of expression of cut, a locus regulating sensory organ identity in Drosophila

Development ◽  
1993 ◽  
Vol 117 (2) ◽  
pp. 441-450 ◽  
Author(s):  
K. Blochlinger ◽  
L.Y. Jan ◽  
Y.N. Jan
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Expression Patterns ◽  
Malpighian Tubules ◽  
Follicle Cells ◽  
Wing Margin ◽  
Sensory Organs ◽  
Tracheal System ◽  
Organ Identity ◽  
The Central Nervous System

The cut locus is both necessary and sufficient to specify the identity of a class of sensory organs in Drosophila embryos. It is also expressed in and required for the development of a number of other embryonic tissues, such as the central nervous system, the Malpighian tubules and the tracheal system. We here describe the expression of cut in the precursors of adult sensory organs. We also show that cut is expressed in cells of the prospective wing margin and correlate the wing margin phenotype caused by two cut mutations with altered cut expression patterns. Finally, we observe cut-expressing cells in other adult tissues, including Malpighian tubules, muscles, the central nervous system and ovarian follicle cells.

Homeotic genes have specific functional roles in the establishment of the Drosophila embryonic peripheral nervous system

Development ◽  
1992 ◽  
Vol 115 (1) ◽  
pp. 35-47 ◽  
Author(s):  
J.G. Heuer ◽  
T.C. Kaufman
Keyword(s):  
Nervous System ◽  
Peripheral Nervous System ◽  
Spatial Patterns ◽  
Ectopic Expression ◽  
Homeotic Genes ◽  
Sensory Organs ◽  
Sex Combs Reduced ◽  
Functional Roles ◽  
Visceral Mesoderm ◽  
Control Segment

The Drosophila embryonic peripheral nervous system (PNS) contains segment-specific spatial patterns of sensory organs which derive from the ectoderm. Many studies have established that the homeotic genes of Drosophila control segment specific characteristics of the epidermis, and more recently these genes have also been shown to control gut morphogenesis through their expression in the visceral mesoderm (Tremml, G. and Bienz, M. (1989), EMBO J. 8, 2677–2685). We report here the roles of homeotic genes in establishing the spatial patterns of sensory organs in the embryonic PNS. The PNS was examined in embryos homozygous for mutations in the homeotic genes Sex combs reduced (Scr), Antennapedia (Antp), Ultrabithorax (Ubx), abdominal-A (abd-A) and Abdominal-B (Abd-B) with antibodies that label specific subsets of sensory organs. Our results suggest that the homeotic genes have specific roles in establishing the correct spatial patterns of sensory organs in their normal domains of expression. In addition, we also report the effects of ectopic expression of the homeotic genes labial (lab), Deformed (Dfd), Scr, Antp or Ubx on the normal development of sensory organs in the embryonic PNS. Interestingly, while previous studies have concluded that ectopic expression of the homeotic genes Dfd, Scr and Antp has no effect on the segmental identity of the abdominal segments, our results demonstrate that this is not true. We show that ectopic expression of these genes does result in the disruption of the developing PNS in the abdomen. Our results are suggestive of a role for the homeotic gene products in regulating genes which are necessary for generating sensory progenitor cells in the developing PNS.

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