Cephalic sense organs and body pores of Xiphinema americanum (Nematoda: Dorylaimoidea)

1980 ◽  
Vol 58 (8) ◽  
pp. 1439-1451 ◽  
Author(s):  
K. A. Wright ◽  
R. Carter
Keyword(s):  
Body Wall ◽  
The Body ◽  
Sheath Cell ◽  
Sense Organs ◽  
Microtubule Organizing Center ◽  
Transmission Electron ◽  
Organizing Center ◽  
Cell Processes ◽  
The Central Nervous System ◽  
Internal Sense

The fine structure of the cephalic sense organs and body pores of the plant parasitic nematode Xiphinema americanum is described by transmission electron microscopy. All of the six inner labial, six outer labial, and four cephalic sense organs as well as the amphids have characteristics indicating chemosensitivity, but there are no clearly identifiable mechanosensitive units. Two pairs of simple internal sense organs, not associated with cuticle, also occur. Sensory dendrites all bear cilium-derived dendritic processes that contain axonemal doublets of microtubules. These doublets show radial and circumferential linkages characteristic of the ciliary necklace region of a cilium, although only an amorphous microtubule organizing center occurs in the usual place of a basal body.Both socket cell and sheath cell processes are associated with the cuticular sense organs. The cell body of the amphidial sheath cell is located well anterior to the central nervous system, before the level of the buccal dilator muscles.Body pores are associated with sensory units characteristic of chemosensitive organs. Hypodermal cells serve as their socket cells, whereas a separate sheath cell occurs in the body wall close to each pore.

Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones

1991 ◽  
Vol 158 (1) ◽  
pp. 37-62 ◽  
Author(s):  
N. I. Syed ◽  
W. Winlow
Keyword(s):  
Body Wall ◽  
Lymnaea Stagnalis ◽  
The Body ◽  
Whole Body ◽  
Pond Snail ◽  
Selective Ablation ◽  
The Central Nervous System ◽  
Body Wall Muscles ◽  
Bilateral Pair ◽  
Left And Right

1. The morphology and electrophysiology of a newly identified bilateral pair of interneurones in the central nervous system of the pulmonate pond snail Lymnaea stagnalis is described. 2. These interneurones, identified as left and right pedal dorsal 11 (L/RPeD11), are electrically coupled to each other as well as to a large number of foot and body wall motoneurones, forming a fast-acting neural network which coordinates the activities of foot and body wall muscles. 3. The left and right sides of the body wall of Lymnaea are innervated by left and right cerebral A cluster neurones. Although these motoneurones have only ipsilateral projections, they are indirectly electrically coupled to their contralateral homologues via their connections with L/RPeD11. Similarly, the activities of left and right pedal G cluster neurones, which are known to be involved in locomotion, are also coordinated by L/RPeD11. 4. Selective ablation of both neurones PeD11 results in the loss of coordination between the bilateral cerebral A clusters. 5. Interneurones L/RPeD11 are multifunctional. In addition to coordinating motoneuronal activity, they make chemical excitatory connections with heart motoneurones. They also synapse upon respiratory motoneurones, hyperpolarizing those involved in pneumostome opening (expiration) and depolarizing those involved in pneumostome closure (inspiration). 6. An identified respiratory interneurone involved in pneumostome closure (visceral dorsal 4) inhibits L/RPeD11 together with all their electrically coupled follower cells. 7. Both L/RPeD11 have strong excitatory effects on another pair of electrically coupled neurones, visceral dorsal 1 and right parietal dorsal 2, which have previously been shown to be sensitive to changes in the partial pressure of environmental oxygen (PO2). 8. Although L/RPeD11 participate in whole-body withdrawal responses, electrical stimulation applied directly to these neurones was not sufficient to induce this behaviour.

scholarly journals The Movements of the Proboscis in Glycera Dibranchiata Ehlers

1937 ◽  
Vol 14 (3) ◽  
pp. 290-301
Author(s):  
G. P. WELLS
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Body Wall ◽  
The Body ◽  
Inhibitory Influence ◽  
Spontaneous Movement ◽  
Arenicola Marina ◽  
Glycera Dibranchiata ◽  
The Central Nervous System ◽  
Nervous Conduction

1. The gut of Glycera consists of (a) the buccal tube, (b) the pharynx, containing the jaws with their associated muscles and glands and the principal stomatogastric ganglia, (c) the oesophagus, leading from the pharynx to (d) the intestine, in which digestion occurs. 2. An "isolated extrovert" preparation is described, consisting of the buccal tube, pharynx and oesophagus. The movements of the buccal tube and oesophagus are recorded separately. The preparation has the following properties: (a) The buccal tube shows vigorous, rapid contractions with a somewhat irregular rhythm. These contractions are due to impulses coming forwards from the pharynx, the buccal tube itself having little power of spontaneous movement. (b) The oesophagus shows tone-waves, on which more rapid contractions of small amplitude may be superposed. These contractions and tone-waves are due to impulses originating in the wall of the oesophagus itself. (c) In a few preparations only, synchronous movements of buccal tube and oesophagus were seen. The site of origin of this synchronous activity was not determined. 3. An "extrovert-body wall" preparation is described, in which the movements of the body wall and buccal tube are separately recorded while the normal nervous conduction paths between them remain intact. The preparation has the following properties: (a) In most cases the body wall shows slight movements only, and the buccal tube moves little or not at all. If, however, the buccal tube be cut across close to the mouth, it begins an irregular rhythm of vigorous contractions, due to impulses originating in the pharynx, which usually continues without diminution for hours. The quiescence of the buccal tube before this cut is made indicates that the central nervous system normally exerts an inhibitory influence on the pharynx. (b) In a few preparations, correlated outbursts of contraction in the body wall and buccal tube were seen. These outbursts, which possibly correspond to extrusion movements of the intact worm, are due to impulses originating in the central nervous system. 4. The results are compared with those previously obtained on Arenicola marina, and reported in an earlier paper.

Pharmacological Induction of Plasticization in the Abdominal Cuticle of Rhodnius

1974 ◽  
Vol 61 (3) ◽  
pp. 705-718
Author(s):  
STUART E. REYNOLDS
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Hormone Receptor ◽  
Body Wall ◽  
Direct Action ◽  
The Body ◽  
Malpighian Tubules ◽  
Diuretic Hormone ◽  
The Central Nervous System ◽  
The Relationship

Injections of 5-hydroxytryptamine (5-HT, serotonin) are found to cause plasticization of the abdominal cuticle of Rhodnius larvae. This plasticization is a direct action of 5-HT on some element in the body wall; the central nervous system is not required. It is probable that 5-HT acts directly at a receptor on the epidermal cells. The relationship between structure and plasticizing activity for a number of 5-HT analogues has been investigated. The receptor resembles other ‘classical’ 5-HT receptors in its requirements, but is unlike the 5-HT/diuretic hormone receptor of Rhodnius Malpighian tubules.

DISTRIBUTION OF CHOLINESTERASE IN THE LARVAE OF HYPODERMA BOVIS AND HYPODERMA LINEATUM (DIPTERA: OESTRIDAE) AND ITS INHIBITION BY SYSTEMIC INSECTICIDES

1967 ◽  
Vol 99 (4) ◽  
pp. 340-350 ◽  
Author(s):  
C. C. Steward
Keyword(s):  
Body Wall ◽  
Fat Body ◽  
Histochemical Demonstration ◽  
The Body ◽  
Lumbar Region ◽  
Salivary Duct ◽  
Ring Gland ◽  
Hypoderma Bovis ◽  
Acetylthiocholine Iodide ◽  
The Central Nervous System

AbstractLarvae of Hypoderma bovis (L.) and H. lineatum (De Vill.) when incubated with the substrate acetylthiocholine iodide showed the presence of cholinesterase throughout the central nervous system and sense organs, in gonads, oenocytes, Malpighian tubes, anlagen of adult structures, part of the posterior midintestine, and at the junctions of the muscles of the body wall. Incubation with the substrate 5-bromoindoxyl acetate showed all the aforementioned and in addition demonstrated the presence of aliesterase (organophosphorus-sensitive esterase) in the cell cytoplasm of all the midintestinal epithelium, the ring gland, tracheal epithelium, salivary duct epithelium, and in the perineurium of the nerve sheath. Aromesterase (organophosphorus-resistant esterase) was particularly abundant in the epithelium of the midintestine. Lipase was prominent in the lipid droplets of the fat body cells and in similar droplets in the haemocytes.When the larvae or their tissues, prior to incubation with the substrates, were treated with any one of the three organophosphorus insecticides coumaphos (Co-Ral), trichlorfon (Neguvon, Dipterex), or Ruelene, the cholinesterase was inhibited and so was much of the aliesterase, but not the aromesterase or lipase. Fixation of the larval tissues in formalin did not result in loss of enzyme activity, but on the other hand was not necessary for good histochemical demonstration of the enzymes.It is concluded that these insecticides by their anticholinesterase action kill the first-instar cattle grubs before the latter can migrate to the lumbar region of the bovine host.

The fine structure of the germinal mass, brood cavity and birth canal of the rediae of the monoxenous hemiuroid digenean Bunocotyle progenetica Chabaud & Buttner, 1959

2019 ◽  
Vol 94 ◽  
Author(s):  
I.M. Podvyaznaya ◽  
A.A. Petrov ◽  
K.V. Galaktionov
Keyword(s):  
Fine Structure ◽  
Life Cycle ◽  
Body Wall ◽  
The Body ◽  
Cellular Composition ◽  
Birth Canal ◽  
Offspring Number ◽  
Transmission Electron ◽  
Reproductive Apparatus ◽  
Germinal Mass

Abstract Bunocotyle progenetica is a hemiuroid digenean whose sexual adults become fully developed and lay their eggs inside the rediae in the molluscan host. In this study, the fine structure of the germinal mass, brood cavity and birth canal in the B. progenetica rediae was examined using transmission electron and confocal microscopy. The large germinal mass attached to the body wall has a cellular composition typical for this organ. The characteristic traits of this germinal mass are weakly developed supporting tissue and the presence of deep lacunae opening into the brood cavity. These lacunae presumably participate in feeding the deeply lying embryos and facilitate their release into the brood cavity. The germinal mass is also characterized by intensive degeneration of cellular elements, which may represent a mechanism controlling the offspring number, limited in this species by the size of the redial brood cavity. The brood-cavity lining consists of flattened cells bearing lamellar projections and is connected anteriorly with the epithelium of the birth canal. The brood-cavity musculature, which is well developed in other hemiuroid digeneans, is significantly reduced in B. progenetica, most likely because their cystophorous cercariae remain inside the rediae, removing the need for muscle contractions pushing them through the brood cavity. The birth canal comprises three regions distinguished by the structure of the lining and muscle arrangement. The comparison of rediae of B. progenetica with parthenitae of other digeneans has shown that the organization of the redial reproductive apparatus in this species may have been influenced by life-cycle modification.

scholarly journals The visceral nervous system of the earthworm: I. Nerves controlling the tone of the alimentary canal

1943 ◽  
Vol 131 (864) ◽  
pp. 271-295 ◽  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Alimentary Canal ◽  
Body Wall ◽  
The Body ◽  
Nerve Supply ◽  
Rhythmic Movements ◽  
Indirect Control ◽  
Pharyngeal Plexus ◽  
The Central Nervous System

The alimentary canal of Lumbricus exhibits autonomous rhythmic movements, probably co-ordinated by nerve elements situated in its walls. The gut is subject to indirect control by extrinsic nerves which fall into two groups mutually antagonistic in their effects. Nerves which augment the tone of the gut muscles leave the central nervous system by the middle and posterior nerves of each segment and join nerve elements (apparently arranged as a plexus) situated in the peritoneum of the body wall, from which nerves pass to enter the gut by the ventro-lateral regions of each septum. Nerves which diminish the tone of the gut leave the central nervous system by the anterior, middle and posterior nerves of each segment and join nerve elements (also probably in the form of a plexus) situated in the muscular layer of the body wall, from which nerves arise to enter the gut via the dorso-lateral region of each septum. The alimentary canal receives another nerve supply from the peripharyngeal commissures of the central nervous system by means of a number of fine plexiform nerves partially embedded in the pharyngeal musculature of either side (pharyngeal plexus). The anatomical relationships of these nerves are described. The pharyngeal plexuses are shown to embody nerve elements which exert an indirect control over the gut, stimulation of these resulting in a fall in tone of all regions of the gut behind the pharynx. The nerve supply of the gut is compared with that which is known in other annelids, and the mechanism of indirect control is compared with that existing in vertebrates.

The host-parasite interface of strigeoid trematodes

Parasitology ◽  
1970 ◽  
Vol 61 (1) ◽  
pp. 35-41 ◽  
Author(s):  
David A. Erasmus
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
The Body ◽  
Sense Organs ◽  
Adhesive Organ ◽  
Transmission Electron ◽  
Transmission Studies ◽  
Host Parasite ◽  
Surface Specialization

A detailed study of the structure of the tegument of D. phoxini has been carried out using probe and transmission electron microscope. The distribution of spines and sense organs on the forebody has been described, as well as the nature of the lappets in the everted and retracted state. The adhesive organ exhibits two different surfaces which also differ from the surface of the rest of the body. The use of the ‘Stereoscan’ has confirmed and extended the concept of surface specialization based on transmission studies.

scholarly journals Human Nudel and NudE as Regulators of Cytoplasmic Dynein in Poleward Protein Transport along the Mitotic Spindle

2003 ◽  
Vol 23 (4) ◽  
pp. 1239-1250 ◽  
Author(s):  
Xiumin Yan ◽  
Fang Li ◽  
Yun Liang ◽  
Yidong Shen ◽  
Xiangshan Zhao ◽  
...  
Keyword(s):  
Protein Transport ◽  
Cytoplasmic Dynein ◽  
Dissociation Rate ◽  
Mitotic Spindles ◽  
Cellular Functions ◽  
Microtubule Organizing Center ◽  
M Phase ◽  
Organizing Center ◽  
The Central Nervous System ◽  
Cycle Dependent

ABSTRACT Emerging evidence supports the idea that a signaling pathway containing orthologs of at least mammalian NudE and Nudel, Lis1, and cytoplasmic dynein is conserved for eukaryotic nuclear migration. In mammals, this pathway has profound impact on neuronal migration during development of the central nervous system. Lis1 and dynein are also involved in other cellular functions, such as mitosis. Here we show that Nudel also participates in a subset of dynein function in M phase. Nudel was specifically phosphorylated in M phase in its serine/threonine phosphorylation motifs, probably by Cdc2 and also Erk1 and -2. A fraction of Nudel bound to centrosomes strongly in interphase and localized to mitotic spindles in early M phase. By using mutants incapable of or simulating phosphorylation, we confirmed that phosphorylation of Nudel regulated the cell-cycle-dependent distribution, possibly by increasing its dissociation rate at the microtubule-organizing center. Moreover, phosphorylated Nudel or the phosphorylation-mimicking mutant bound Lis1 more efficiently. We further demonstrated that a Nudel mutant incapable of binding to Lis1 impaired the poleward movement of dynein and hence the dynein-mediated transport of kinetochore proteins to spindle poles along microtubules, a process contributing to inactivation of the spindle checkpoint in mitosis. These results point to the importance of Nudel-Lis1 interaction for the dynein activity in M phase and to a possible role of Nudel phosphorylation as facilitating such interaction. In addition, comparative studies suggest that NudE is also functionally related to its paralog, Nudel.

scholarly journals Ultrastructure of the buccal capsule in the adult female Anguillicoloides crassus (Nematoda: Anguillicolidae)

2010 ◽  
Vol 47 (3) ◽  
pp. 170-178 ◽  
Author(s):  
M. Bruňanská ◽  
H. Fagerholm ◽  
F. Moravec ◽  
Z. Vasilková
Keyword(s):  
Adult Female ◽  
Cross Sections ◽  
Body Wall ◽  
Buccal Capsule ◽  
The Body ◽  
Transmission Electron ◽  
Junctional Complexes ◽  
Marginal Cells ◽  
First Time ◽  
Anguillicoloides Crassus

Abstract The fine structure of the buccal capsule of the adult female nematode Anguillicoloides crassus (Spirurina) was studied for the first time. Results are based on serial section (longitudinal and transverse) light and transmission electron microscopy. The buccal capsule of A. crassus is a cuticular-lined structure. It can be divided into three main parts: cheilostom, gymnostom and stegostom. The cheilostom is the anterior region of the buccal capsule with the cuticular lining continuous with the body wall cuticle and underlain by epidermal syncytia. The gymnostom is a cuticular region with portions of it very electron dense and underlain by arcade syncytia. A dense circumoral cylinder together with the circumpharyngeal ring represent the prominent characters of the gymnostom. The stegostom is formed by anterior pharyngeal cuticle underlain by muscular radial cells and epithelial marginal cells. The cephalic cuticle of A. crassus makes a direct contact with the pharyngeal cuticle at the base of the circumoral cylinder, within a circumpharyngeal ring containing projections of pharyngeal muscular and marginal cells. The circumoral cylinder, circumpharyngeal ring and pharynx are connected to the body epidermis by junctional complexes. The buccal capsule includes occasionally 3 projections of the pharynx evidently observed in serial cross sections. These ultrastructural characters may provide useful data for comparative, functional as well as evolutionary studies within the Chromadorea.

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