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Slit sense organ distribution on the legs of two species of orb-weaving spider (Araneae: Araneidae).Arthropod Structure & Development Mar 2022Biotic and abiotic mechanical stimuli are ubiquitous in the environment, and are a widely used source of sensory information in arthropods. Spiders sense mechanical...
Biotic and abiotic mechanical stimuli are ubiquitous in the environment, and are a widely used source of sensory information in arthropods. Spiders sense mechanical stimuli using hundreds of slit sense organs (small isolated slits, large isolated slits, groups of slits and lyriform organs) distributed across their bodies and appendages. These slit sense organs are embedded in the exoskeleton and detect cuticular strain. Therefore, the spatial pattern of these sensors can give clues into how mechanical stimuli from different sources might be processed and filtered as they are transmitted through the body. Here, we map the distribution of slit sense organs on the legs in two species of orb-weaving spider, A. diadematus and T. edulis, in which slit sense organ distribution has not previously been investigated. We image the spiders' legs using scanning electron microscopy, and trace the position and orientation of slits on these images to describe the distribution and external morphology of the slit sense organs. We show that both species have a similar distribution of slit sense organs, with small isolated slits occurring in consistent lines parallel to the long axis of the legs, whilst large isolated slits, groups of slits and lyriform organs appear in fixed positions near the leg joints. Our findings support what has been described in the literature for several other species of spider, which indicates that slit organ arrangement is conserved across spiders in different evolutionary lineages and with disparate hunting strategies. The dispersed distribution of small isolated slits along the whole length of the leg may be used to detect large-scale strain of the leg segment as a result of muscle activity or internal changes in haemolymph pressure.
Topics: Animals; Extremities; Microscopy, Electron, Scanning; Sense Organs; Spiders
PubMed: 35137691
DOI: 10.1016/j.asd.2022.101140 -
BMC Biology Feb 2021Insects and other arthropods utilise external sensory structures for mechanosensory, olfactory, and gustatory reception. These sense organs have characteristic shapes...
Insects and other arthropods utilise external sensory structures for mechanosensory, olfactory, and gustatory reception. These sense organs have characteristic shapes related to their function, and in many cases are distributed in a fixed pattern so that they are identifiable individually. In Drosophila melanogaster, the identity of sense organs is regulated by specific combinations of transcription factors. In other arthropods, however, sense organ subtypes cannot be linked to the same code of gene expression. This raises the questions of how sense organ diversity has evolved and whether the principles underlying subtype identity in D. melanogaster are representative of other insects. Here, we provide evidence that such principles cannot be generalised, and suggest that sensory organ diversification followed the recruitment of sensory genes to distinct sensory organ specification mechanism. RESULTS: We analysed sense organ development in a nondipteran insect, the flour beetle Tribolium castaneum, by gene expression and RNA interference studies. We show that in contrast to D. melanogaster, T. castaneum sense organs cannot be categorised based on the expression or their requirement for individual or combinations of conserved sense organ transcription factors such as cut and pox neuro, or members of the Achaete-Scute (Tc ASH, Tc asense), Atonal (Tc atonal, Tc cato, Tc amos), and neurogenin families (Tc tap). Rather, our observations support an evolutionary scenario whereby these sensory genes are required for the specification of sense organ precursors and the development and differentiation of sensory cell types in diverse external sensilla which do not fall into specific morphological and functional classes. CONCLUSIONS: Based on our findings and past research, we present an evolutionary scenario suggesting that sense organ subtype identity has evolved by recruitment of a flexible sensory gene network to the different sense organ specification processes. A dominant role of these genes in subtype identity has evolved as a secondary effect of the function of these genes in individual or subsets of sense organs, probably modulated by positional cues.
Topics: Animals; Gene Expression; Larva; RNA Interference; Sense Organs; Tribolium
PubMed: 33546687
DOI: 10.1186/s12915-021-00948-y -
Progress in Neurobiology Feb 1994Genetic analysis of development in Drosophila melanogaster has advanced our understanding of "position reading", where the expression of particular genes informs a cell... (Review)
Review
Genetic analysis of development in Drosophila melanogaster has advanced our understanding of "position reading", where the expression of particular genes informs a cell of its position in the developing animal. The first step in localization of fly sense organs is the local expression of a gene conferring neural competence on epidermal cells. The four genes of the achaete-scute (AS-C) complex play crucial roles in the localization of sense organs. The resolution of local expression of AS-C genes along one dimension is about 10%; accuracy is improved by the balancing local expression of AS-C antagonist genes such as extramacrochaete. Position reading seems to depend primarily on such patterns of gene expression, and not upon the compartmental identity of the cells. No evidence has been found for differing roles of the four AS-C genes in the generation of sense organ progenitor cells or in the specification of neuronal properties of innervating neurons. The formation of each sense organ may be a unique case where the different proneural and neurogenic gene products have varying importance, and fortuitous local effects acting on this complex combination of factors have come to be important. The fly may be evolving from a flexible regular pattern to an inflexible irregular pattern strongly dependent on local factors, turning the fly into a crystallized system. (Written by R. Wayne Davies.).
Topics: Animals; Drosophila melanogaster; Embryo, Nonmammalian; Gene Expression; Sense Organs
PubMed: 8008828
DOI: 10.1016/0301-0082(94)90068-x -
Die Naturwissenschaften Jan 1997Sense organs filter relevant information from a broad background of physical interactions and discard possible perceptual input that has not proven useful during the... (Review)
Review
Sense organs filter relevant information from a broad background of physical interactions and discard possible perceptual input that has not proven useful during the course of biological evolution. Sense organs not only limit the access to physical reality, under certain conditions they have a life of their own and produce responses even in the absence of physical stimulation. As a perfect example, the inner ear, the cochlea, in addition to detecting incoming sound waves, it also is capable of producing sound energy. Such "active" processes, however, seem to be necessary to push detection thresholds close to physical limits. The price that has to be paid are "cochlear artifacts" like otoacoustic emissions. In the following, measurement of sound that is emitted by the ear will be introduced as a noninvasive means to assess cochlear function and to help to unravel the mechanical interaction between sensory cells and supporting structures that ultimately leads to sensitive and sharply tuned auditory perception. One focus will be on the cochlea of echo-locating bats that use audition as the main window of perception to their environment and therefore have highest demands on cochlear performance.
Topics: Animals; Auditory Perception; Basilar Membrane; Cochlea; Hair Cells, Auditory; Hearing; Mammals; Models, Biological; Sound
PubMed: 9050002
DOI: 10.1007/s001140050339 -
Journal of Comparative Physiology. A,... May 2006Birds are bipedal animals with a center of gravity rostral to the insertion of the hindlimbs. This imposes special demands on keeping balance when moving on the ground.... (Review)
Review
Birds are bipedal animals with a center of gravity rostral to the insertion of the hindlimbs. This imposes special demands on keeping balance when moving on the ground. Recently, specializations in the lumbosacral region have been suggested to function as a sense organ of equilibrium which is involved in the control of walking. Morphological, electrophysiological, behavioral and embryological evidence for such a function is reviewed. Birds have two nearly independent kinds of locomotion and it is suggested that two different sense organs play an important role in their respective control: the vestibular organ during flight and the lumbosacral system during walking.
Topics: Animals; Birds; Gait; Lumbosacral Region; Sense Organs; Spinal Canal; Walking
PubMed: 16450117
DOI: 10.1007/s00359-006-0105-x -
Journal of Experimental Zoology. Part... Sep 2011A century has passed since the discovery of the paratympanic organ (PTO), a mechanoreceptive sense organ in the middle ear of birds and other tetrapods. This luminal... (Review)
Review
A century has passed since the discovery of the paratympanic organ (PTO), a mechanoreceptive sense organ in the middle ear of birds and other tetrapods. This luminal organ contains a sensory epithelium with typical mechanosensory hair cells and may function as a barometer and altimeter. The organ is arguably the most neglected sense organ in living tetrapods. The PTO is believed to be homologous to a lateral line sense organ, the spiracular sense organ of nonteleostean fishes. Our review summarizes the current state of knowledge of the PTO and draws attention to the astounding lack of information about the unique and largely unexplored sensory modality of barometric perception.
Topics: Altitude; Animals; Atmospheric Pressure; Birds; Chickens; Ear, Middle; Epithelium; Fishes; Hair Cells, Auditory; Lateral Line System; Sense Organs; Tympanic Membrane
PubMed: 21721119
DOI: 10.1002/jez.b.21422 -
Developmental Dynamics : An Official... Aug 2000The Drosophila Distal-less (Dll) gene was identified in the early 1980s by means of dominant and recessive mutations that caused both striking antenna-to-leg... (Review)
Review
The Drosophila Distal-less (Dll) gene was identified in the early 1980s by means of dominant and recessive mutations that caused both striking antenna-to-leg transformations and leg truncations. The gene initially was named "Bristle on arista" or "Brista" because one aspect of the phenotype is the formation of leg bristles on the antenna (Sato [1984] Drosophila Information Service 60:180-182; Sunkel and Whittle [1987] Wilhelm Roux's. Arch. Dev. Biol. 196:124-132). Subsequent studies have revealed that Dll encodes a homeodomain transcription factor (Cohen et al. [1989] Nature 338:432-434) that is expressed throughout limb development from embryogenesis on (Cohen [1990] Nature 343:173-177; Weigmann and Cohen [1999] Development 126:3823-3830). Dll is required for the elaboration of distal pattern elements in the antenna, the legs, the limb-derived gnathal structures (Cohen and Jurgens [1989] Nature 482-485), and the anal plate (Gorfinkiel et al. [1999] Mech. Dev. 868:113-123) and can initiate proximodistal axis formation when expressed ectopically (Gorfinkiel et al. [1997] Genes Dev. 11:2259-2271). Dll homologs are expressed in developing appendages in at least six coelomate phyla, including chordates (Akimenko et al. [1994] J. Neurosci. 14:3475-3486; Beauchemin and Savard [1992] Dev. Biol. 154:55-65; Bulfone et al. [1993] Mech. Dev. 40:129-140; Dolle et al. [1992] Differentiation 49:93-99; Ferrari et al. [1995] Mech. Dev. 52:257-264; Panganiban et al. [1997] Proc. Natl. Acad. Sci. USA 94:5162-5166; Simeone et al. [1994] Proc. Natl. Acad. Sci. USA 91:2250-2254), consistent with requirements for Dlx function in normal limb development across the animal kingdom. Distal-less also has been implicated in various aspects of vertebrate neurogenesis (see reviews by Kraus and Lufkin [1999] J. Cell. Biochem. 32-33:133-140 and the accompanying review by Beanan and Sargent [2000] Dev. Dyn. 218:000-000). Here, I outline what is known about Dll function and regulation in Drosophila.
Topics: Animals; Drosophila; Extremities; Gene Expression Regulation, Developmental; Homeodomain Proteins; Models, Genetic; Sense Organs; Time Factors; Transcription Factors; Wings, Animal
PubMed: 10906775
DOI: 10.1002/1097-0177(200008)218:4<554::AID-DVDY1023>3.0.CO;2-# -
Mechanisms of Development Dec 2000We have shown that the basic helix-loop-helix transcription factor Atonal is sufficient for specification of one of the three subsets of olfactory sense organs on the...
We have shown that the basic helix-loop-helix transcription factor Atonal is sufficient for specification of one of the three subsets of olfactory sense organs on the Drosophila antenna. Misexpression of Atonal in all sensory precursors in the antennal disc results in their conversion to coeloconic sensilla. The mechanism by which specific sense organ fate is triggered remains unclear. We have shown that the homeodomain transcription factor Cut which acts in the chordotonal-external sense organ choice does not play a role in olfactory sense organ development. The expression of atonal in specific domains of the antennal disc is regulated by an interplay of the patterning genes, Hedgehog and Wingless, and Drosophila epidermal growth factor receptor pathway.
Topics: Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Lineage; DNA-Binding Proteins; Down-Regulation; Drosophila Proteins; Drosophila melanogaster; Epidermal Growth Factor; Hedgehog Proteins; Homeodomain Proteins; Immunohistochemistry; Insect Proteins; Models, Genetic; Nerve Tissue Proteins; Nuclear Proteins; Proto-Oncogene Proteins; Sense Organs; Signal Transduction; Time Factors; Transcription Factors; Wnt1 Protein
PubMed: 11091078
DOI: 10.1016/s0925-4773(00)00487-1 -
Development (Cambridge, England) Jun 2017Perception of the environment in vertebrates relies on a variety of neurosensory mini-organs. These organs develop via a multi-step process that includes placode... (Review)
Review
Perception of the environment in vertebrates relies on a variety of neurosensory mini-organs. These organs develop via a multi-step process that includes placode induction, cell differentiation, patterning and innervation. Ultimately, cells derived from one or more different tissues assemble to form a specific mini-organ that exhibits a particular structure and function. The initial building blocks of these organs are epithelial cells that undergo rearrangements and interact with neighbouring tissues, such as neural crest-derived mesenchymal cells and sensory neurons, to construct a functional sensory organ. In recent years, advances in imaging methods have allowed direct observation of these epithelial cells, showing that they can be displaced within the epithelium itself via several modes. This Review focuses on the diversity of epithelial cell behaviours that are involved in the formation of small neurosensory organs, using the examples of dental placodes, hair follicles, taste buds, lung neuroendocrine cells and zebrafish lateral line neuromasts to highlight both well-established and newly described modes of epithelial cell motility.
Topics: Animals; Cell Differentiation; Cell Movement; Epithelial Cells; Humans; Organogenesis; Sense Organs; Sensory Receptor Cells
PubMed: 28559238
DOI: 10.1242/dev.148122 -
Cytoskeleton (Hoboken, N.J.) Oct 2020The apical organ of ctenophores is the center of sensory information that controls locomotion. Previous studies have described several types of cilia in this organ....
The apical organ of ctenophores is the center of sensory information that controls locomotion. Previous studies have described several types of cilia in this organ. However, detailed ciliary structures, particularly axonemal structures, have not been extensively investigated. Here, we reported that the apical organ of the ctenophore Bolinopsis mikado contains six types of cilia with different axonemal structures. These include the typical "9 + 2" motile axonemes, with both outer and inner dynein arms, only the inner dynein arm, or no dynein arm; axonemes with electron-dense structures in the A-tubules; "9 + 0" axonemes lacking the central pair of microtubules; and axonemes with compartmenting lamellae. Considering that "9 + 2" axonemal structures with both dynein arms are thought to be ancestral forms of cilia, the apical organ of ctenophores would comprise an elaborate assembly of modified ciliary forms that sense and transmit extracellular stimuli and generate various fluid flows.
Topics: Animals; Cilia; Ctenophora; Sense Organs
PubMed: 33103333
DOI: 10.1002/cm.21640