Comparison of early nerve cord development in insects and vertebrates

Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2309-2325 ◽  
Author(s):  
D. Arendt ◽  
K. Nubler-Jung
Keyword(s):  
Neural Progenitor Cells ◽  
Regional Distribution ◽  
Cell Types ◽  
Molecular Data ◽  
Body Cavity ◽  
The Body ◽  
Lateral Nerve ◽  
Nerve Roots ◽  
Commissural Axons ◽  
Lateral Column

It is widely held that the insect and vertebrate CNS evolved independently. This view is now challenged by the concept of dorsoventral axis inversion, which holds that ventral in insects corresponds to dorsal in vertebrates. Here, insect and vertebrate CNS development is compared involving embryological and molecular data. In insects and vertebrates, neurons differentiate towards the body cavity. At early stages of neurogenesis, neural progenitor cells are arranged in three longitudinal columns on either side of the midline, and NK-2/NK-2.2, ind/Gsh and msh/Msx homologs specify the medial, intermediate and lateral columns, respectively. Other pairs of regional specification genes are, however, expressed in transverse stripes in insects, and in longitudinal stripes in the vertebrates. There are differences in the regional distribution of cell types in the developing neuroectoderm. However, within a given neurogenic column in insects and vertebrates some of the emerging cell types are remarkably similar and may thus be phylogenetically old: NK-2/NK-2.2-expressing medial column neuroblasts give rise to interneurons that pioneer the medial longitudinal fascicles, and to motoneurons that exit via lateral nerve roots to then project peripherally. Lateral column neuroblasts produce, among other cell types, nerve root glia and peripheral glia. Midline precursors give rise to glial cells that enwrap outgrowing commissural axons. The midline glia also express netrin homologs to attract commissural axons from a distance.

A new Gymnotus (Teleostei: Gymnotiformes: Gymnotidae) from the Pantanal Matogrossense of Brazil and adjacent drainages: continued documentation of a cryptic fauna

Zootaxa ◽  
2005 ◽  
Vol 933 (1) ◽  
pp. 1 ◽  
Author(s):  
FLORA M.C. FERNANDES ◽  
JAMES S. ALBERT ◽  
MARIA D.F.Z. DANIEL-SILVA ◽  
CARLOS E. LOPES ◽  
WILLIAM G.R. CRAMPTON ◽  
...  
Keyword(s):  
New Species ◽  
Lateral Line ◽  
Dna Amplification ◽  
Molecular Data ◽  
Body Cavity ◽  
The Body ◽  
New Taxon ◽  
Neotropical Fishes ◽  
Posterior Lateral Line ◽  
Floating Macrophytes

Here we describe a new species of Gymnotus, G. pantanal n. sp., from the Pantanal Matogrossense of Brazil, using morphological, cytogenetic, and molecular data. Specimens ascribed to the new species are also known from areas downstream in Paraguay, and from the adjacent Guaporé basin of Bolivia. The new species most closely resembles G. anguillaris in possessing an elongate body, slender profile, long body cavity, and shorter head than other congeners. The new species also resembles G. anguillaris in the presence of pale narrow bands restricted to the area below the lateral line on the anterior half of the body. The new taxon differs from G. anguillaris in possessing more narrowly set eyes, a wider and deeper head, a larger branchial opening, longer pectoral fins with more fin rays, and fewer pored posterior lateral-line scales. The new species inhabits rooted grasses and floating macrophytes in small creeks and along the banks of larger blackwater rivers. Populations are found syntoptically with G. inaequilabiatus and G. sylvius. Compared with these species, the new species exhibits a distinct combination of microsatellite DNA amplification patterns, and chromosomal and external features. These results confirm earlier studies showing the power of a multidisciplinary approach to characterizing the enormous and often cryptic diversity of Neotropical fishes.

Determination and transdetermination in imaginal disks of Drosophila (Summary only)

1970 ◽  
Vol 176 (1044) ◽  
pp. 291-293
Keyword(s):  
Single Cells ◽  
Body Part ◽  
Cell Types ◽  
Structural Features ◽  
Theoretical Concept ◽  
Body Cavity ◽  
The Body ◽  
Body Region ◽  
Body Parts ◽  
Imaginal Disks

It is generally assumed that in multicellular organisms the diversity of the different cell types is the result of different gene activity which becomes manifest in the course of development. This theoretical concept of cell differentiation was developed on the basis of results obtained from a relatively small number of suitable experimental systems. One of them comprises the imaginal disks of the fruitfly Drosophila melanogaster . Imaginal disks are larval primordia in holometabolic insects such as flies and mosquitoes, and consist of densely packed populations of morphologically uniform cells. They give rise to defined structures of the adult body (mainly integument), thus replacing parts of the larva which are almost completely histolysed during metamorphosis. The prospective fate of the various imaginal disks can be tested, for example, by transplantation experiments. Individual disks are removed from larvae of a genetically marked strain and transplanted into the body cavity of another larva with which the transplants undergo metamorphosis. The metamorphosed derivatives of the disks are then found in the abdomen of the fly and can be microscopically identified on the basis of the morphology of bristles, hairs and other structural features of the integument. The same method is applied for examination of the developmental performance of disk fragments. From the results of such experiments the following conclusions are drawn: (1) Individual disks of fully grown larvae, that is larvae which are ready to pupate, are determined (programmed) for exactly defined body parts of the adult organism. (2) The individual subregions of such a body part can be localized precisely within a disk. Based on these facts fate maps (anlage plans) can be worked out. (3) From experiments in which different genetically marked disks are intermingled and then transplanted into larvae it is concluded that even single cells are determined for structures of a specific body region.

scholarly journals First description of male Philometra thaiensis Moravec, Fiala et Dyková, 2004 (Nematoda: Philometridae) from the body cavity of the eyespot pufferfish Tetraodon biocellatus Tirant, and evolutionary relationships of this species with other dracunculoids as inferred from SSU rRNA gene sequences

2014 ◽  
Vol 51 (3) ◽  
pp. 236-245 ◽  
Author(s):  
K. Quiazon ◽  
T. Yoshinaga ◽  
H. Doi ◽  
J. Araki ◽  
K. Ogawa
Keyword(s):  
18S Rrna ◽  
Molecular Data ◽  
Small Subunit ◽  
Body Cavity ◽  
The Body ◽  
Evolutionary Relationships ◽  
Rrna Gene ◽  
Taxonomic Identification ◽  
Ssu Rrna ◽  
First Time

Abstract Finding male philometrid nematodes is essential for taxonomic identification among congeneric species. In this study, male Philometra thaiensis Moravec, Fiala et Dyková, 2004 were collected and described for the first time, from the body cavity of the freshwater fish (eyespot pufferfish) Tetraodon biocellatus Tirant (Tetraodontiformes, Tetraodontidae), and conspecific females were redescribed based on the additional morphological biometrics examined. Molecular examination was carried out on the small subunit 18S rRNA, revealing the evolutionary relationships of P. thaiensis and reported philometrid species (Philometra and Philometroides) from Japan with other dracunculoids deposited in the GenBank. Based on the molecular data, there are some genera (Philometra, Philometroides, Clavinema, and Margolisianum [genus inquirendum]) requiring further morphological re-evaluation that should be supported with molecular data.

scholarly journals The pericardium of Oikopleura dioica (Tunicata, Appendicularia) contains two distinct cell types and is rotated by 90 degrees to the left

Zoomorphology ◽  
2021 ◽  
Author(s):  
Mai-Lee Van Le ◽  
Maria Novosolov ◽  
Dorothee Huchon ◽  
Thomas Stach
Keyword(s):  
Basal Lamina ◽  
Cell Types ◽  
Body Cavity ◽  
The Body ◽  
Last Common Ancestor ◽  
Myocardial Cells ◽  
Oikopleura Dioica ◽  
Peritoneal Cells ◽  
Distinct Cell ◽  
Primary Body

AbstractThe planktonic Oikopleura dioica belongs to Tunicata, the probable sister taxon to Craniota, and might show plesiomorphic characters, conserved from the common lineage of Tunicata and Craniota. In O. dioica a pericardium in a position similar to other chordates but also to the heart and pericardium of craniates is found. Surprisingly, little is known about the ultrastructure of the pericardium in O. dioica. Here, we show based on electron microscopy that the pericardium is completely lined by a single layer of 16 epithelial cells: 6 epithelial myocardial cells on the left side of the pericardium and 10 peritoneal cells constituting the right side. One of the peritoneal cells, situated at the ventral border between peritoneal cells and myocardial cells has an extension that anchors the pericardium to the basal lamina beneath the latero-ventral epidermis. The primary body cavity of O. dioica appears quite uniformly clear in electron microscopic aspect but several sheets, resembling the basal lamina of the pericardium cross the larger spaces of the body cavity and connect to the pericardial basal lamina. This is the first detailed description of two distinct cell types in the epithelial lining of the pericardium of O. dioica. In comparison with other chordates, we conclude that two cell types can be reconstructed for the last common ancestor of Chordata at least. The position of the pericardium at the intersection of trunk and tail in combination with the basal-lamina like sheets spanning the hemocoel is probably of importance for the function of the circulation of the hemocoelic fluid. Similar to the tail, the axis of the pericardium is shifted through 90 degrees to the left as compared to the main body axis of the trunk and we infer that this shift is an apomorphic character of Appendicularia.

scholarly journals Responses and coping methods of different testicular cell types to heat stress: overview and perspectives

2021 ◽  
Author(s):  
Hui Cai ◽  
Dezhe Qin ◽  
Sha Peng
Keyword(s):  
Heat Stress ◽  
Leydig Cells ◽  
Cell Types ◽  
Cellular Responses ◽  
Body Cavity ◽  
The Body ◽  
Testicular Cell ◽  
Coping Methods ◽  
And Coping ◽  
Different Cell Types

To facilitate temperature adjustments, the testicles are located outside the body cavity. In most mammals, the temperature of the testes is lower than the body temperature to ensure the normal progression of spermatogenesis. Rising temperatures affect spermatogenesis and eventually lead to a decline in male fertility or even infertility. However, the testes are composed of different cell types, including spermatogonial stem cells, spermatocytes, spermatozoa, Leydig cells, and Sertoli cells, which have different cellular responses to heat stress. Recent studies have shown that using different drugs can relieve heat-stress-induced reproductive damage by regulating different signaling pathways. Here, we review the mechanisms by which heat stress damages different cells in testes and possible treatments.

scholarly journals Molecular Aspects of Regeneration Mechanisms in Holothurians

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 250 ◽  
Author(s):  
Igor Yu. Dolmatov
Keyword(s):  
Spatial Organization ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Molecular Data ◽  
The Body ◽  
Matrix Remodeling ◽  
Oxygen Species ◽  
Morphological And Molecular Data ◽  
Molecular Aspects ◽  
Different Cell Types

Holothurians, or sea cucumbers, belong to the phylum Echinodermata. They show good regenerative abilities. The present review provides an analysis of available data on the molecular aspects of regeneration mechanisms in holothurians. The genes and signaling pathways activated during the asexual reproduction and the formation of the anterior and posterior parts of the body, as well as the molecular mechanisms that provide regeneration of the nervous and digestive systems, are considered here. Damage causes a strong stress response, the signs of which are recorded even at late regeneration stages. In holothurian tissues, the concentrations of reactive oxygen species and antioxidant enzymes increase. Furthermore, the cellular and humoral components of the immune system are activated. Extracellular matrix remodeling and Wnt signaling play a major role in the regeneration in holothurians. All available morphological and molecular data show that the dedifferentiation of specialized cells in the remnant of the organ and the epithelial morphogenesis constitute the basis of regeneration in holothurians. However, depending on the type of damage, the mechanisms of regeneration may differ significantly in the spatial organization of regeneration process, the involvement of different cell types, and the depth of reprogramming of their genome (dedifferentiation or transdifferentiation).

scholarly journals Molecular and cellular architecture of the larval sensory organ in the cnidarian Nematostella vectensis

2021 ◽  
Author(s):  
Callum Teeling ◽  
Eleanor Gilbert ◽  
Siffreya Pedersen ◽  
Nathan Chrismas ◽  
Vengamanaidu Modepalli
Keyword(s):  
In Situ Hybridisation ◽  
Cell Types ◽  
Molecular Data ◽  
The Body ◽  
Molecular Signature ◽  
Sensory Organ ◽  
Nematostella Vectensis ◽  
Secretory Cells ◽  
Apical Region ◽  
Apical Domain

The apical pole of eumetazoan ciliated larvae acts as a neurosensory structure and is principally composed of sensory-secretory cells. Cnidarians like the sea anemone Nematostella vectensis are the only non-bilaterian group to evolve ciliated larvae with a neural integrated sensory organ that is likely homologous to bilaterians. Here, we uncovered the molecular signature of the larval sensory organ in Nematostella by generating a transcriptome of the apical tissue. We characterised the cellular identity of the apical domain by integrating larval single-cell data with the apical transcriptome and further validated this through in-situ hybridisation. We discovered that the apical domain comprises a minimum of 6 distinct cell types, including apical cells, neurons, peripheral flask-shaped gland/secretory cells, and undifferentiated cells. By profiling the spatial expression of neuronal genes, we showed that the apical region has a unique neuronal signature distinct from the rest of the body. By combining the planula cilia proteome with the apical transcriptome data, we revealed the sheer complexity of the non-motile apical tuft. Overall, we present comprehensive spatial/molecular data on the Nematostella larval sensory organ and open new directions for elucidating the functional role of the apical organ and larval nervous system.

Morphological and molecular characterization of an enigmatic clinostomid trematode (Digenea: Clinostomidae) parasitic as metacercariae in the body cavity of freshwater fishes (Cichlidae) across Middle America

2018 ◽  
Vol 93 (04) ◽  
pp. 461-474 ◽  
Author(s):  
R. Briosio-Aguilar ◽  
M. García-Varela ◽  
D.I Hernández-Mena ◽  
M. Rubio-Godoy ◽  
G. Pérez-Ponce de León
Keyword(s):  
Phylogenetic Relationships ◽  
Freshwater Fishes ◽  
Molecular Data ◽  
Body Cavity ◽  
The Body ◽  
Valid Species ◽  
The Family ◽  
Middle America ◽  
Molecular Phylogenetic ◽  
Morphological And Molecular Data

AbstractThe family Clinostomidae Lühe, 1901 contains 29 species allocated to seven genera, of whichClinostomumLeidy, 1856 is the most diverse, withc.14 valid species. The diversity ofClinostomumhas been assessed, combining morphological and molecular data. The genetic library for species in this genus has increased steadily, although there is little or no information for the other genera included in the family. Molecular phylogenetic relationships among the genera of clinostomids have not been assessed, and their classification is still based on morphological traits. The monotypicIthyoclinostomumwas described from a fish-eating bird in Brazil, and its metacercariae have been found in several locations in South America, parasitizing erythrinid freshwater fishes. We collected unusually large metacercariae from the body cavity of cichlids in several locations across Middle America. These metacercariae exhibited some resemblance toIthyoclinostomum, although several differences prevent their inclusion inIthyoclinostomum dimorphum, casting doubt on their taxonomic identification. The main objective of this paper was to characterize the metacercariae collected in cichlids using both morphology and molecular data from three molecular markers, and to assess the molecular phylogenetic relationships among the genera of Clinostomidae to establish the position of the newly generated sequences. We took a conservative position and tentatively placed the metacercariae as belonging toIthyoclinostomum.

The muscle, nervous and excretory systems of the plerocercoid of Callitetrarhynchus gracilis (Rud., 1819) (Pintner 1931) (Cestoda: Trypanorhyncha) from Bermuda fishes

Parasitology ◽  
1988 ◽  
Vol 96 (2) ◽  
pp. 337-351 ◽  
Author(s):  
F. Gwendolen Rees
Keyword(s):  
Body Wall ◽  
Body Cavity ◽  
The Body ◽  
Lateral Nerve ◽  
Central Ring ◽  
Rigid Ring ◽  
Glandular Cells ◽  
Nerve Cords ◽  
Extrinsic Muscles

SummaryThe plerocercoid of Callitetrarhynchus gracilis was found in the body cavity of 14 species of fishes from Bermuda. The scolex, having completed its development, continues to grow within the blastocyst. The two mobile bothridia possess lateral grooves containing backwardly directed spines. Rapid evagination of the proboscides is effected by two layers of contra-rotating spiral muscles in the walls of the proboscis bulbs. The proboscis retractor is protected from constriction, during contraction of the bulbs, by a rigid ring at the junction of bulb and sheath. Nine series of extrinsic muscles anchor the proboscis sheaths to the body wall and a ladder-like series of dorsal, ventral and lateral muscles anchors the bulbs to one another. The bulbar nerves arise from the lateral nerve cords and are joined by a series of central ring commissures along the length of the bulbs. Uniciliate sensilla occur on the scolex and glandular cells in the peduncle.

The musculature and nervous system of the plerocercoid larva of Dibothriorhynchus grossum (Rud.)

Parasitology ◽  
1941 ◽  
Vol 33 (4) ◽  
pp. 373-389 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Nervous System ◽  
Muscle Mass ◽  
Nerve Cells ◽  
The Body ◽  
Lateral Nerve ◽  
Posterior Median ◽  
The Brain ◽  
Ventral Muscle ◽  
Nerve Cords ◽  
Extrinsic Muscles

1. The structure of the proboscides of the larva of Dibothriorhynchus grossum (Rud.) is described. Each proboscis is provided with four sets of extrinsic muscles, and there is an anterior dorso-ventral muscle mass connected to all four proboscides.2. The musculature of the body and scolex is described.3. The nervous system consists of a brain, two lateral nerve cords, two outer and inner anterior nerves on each side, twenty-five pairs of bothridial nerves to each bothridium, four longitudinal bothridial nerves connecting these latter before their entry into the bothridia, four proboscis nerves arising from the brain, and a series of lateral nerves supplying the lateral regions of the body.4. The so-called ganglia contain no nerve cells, these are present only in the posterior median commissure which is therefore the nerve centre.

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