Buccal capsule and intestine ultrastructure of the marine predatory nematode Sphaerolaimus balticus (Monhysterida: Sphaerolaimidae)

Nematology ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 327-342
Author(s):  
Alexei V. Tchesunov ◽  
Maria A. Fedyaeva
Keyword(s):  
Basal Lamina ◽  
Major Part ◽  
Buccal Capsule ◽  
Peritrophic Membrane ◽  
Marine Nematode ◽  
Posterior Portion ◽  
Longitudinal Ribs ◽  
Ultrastructural Morphology ◽  
Lipid Granules ◽  
Somatic Muscles

Summary The ultrastructural morphology of the buccal capsule and intestine (mid-gut) of the predatory marine nematode Sphaerolaimus balticus is investigated. The major part of the voluminous barrel-shaped buccal capsule is made up of strongly modified somatic cuticle and hence presents itself as an intricately differentiated cheilostome. The latter consists of three compartments: i.e., i) labial region; ii) striated region with six rows of fine longitudinal ribs; and iii) shagreen band penetrated by about ten projections of arcade tissue. The gymnostome and telostome are narrow and together constitute a small posterior portion of the buccal capsule. The mouth is evidently opened by contraction of anterior longitudinal somatic muscles. The intestine is characterised by a very thin and homogenous basal lamina. The cytoplasm of the enterocytes contains lipid granules, large electron-light vacuoles and rounded concentric inclusions in membranous vacuoles. Apical microvilli are separated from the lumen by a dense three-layered glycocalyx resembling the peritrophic membrane in the intestine of arthropods. The glycocalyx is only a supportive structure of the mid-gut. The most peculiar features of the intestine are the particularly strong junctions connecting the glycocalyx with the cells. The junctions appear as cytoplasmic bundles attached to the dense glycocalyx layer by dint of hemidesmosomes.

Ultrastructure of the Epidermis and Protonephridium of an Undescribed Species of Luridae (Platyhelminthes, Rhabdocoela)

1993 ◽  
Vol 41 (4) ◽  
pp. 415 ◽  
Author(s):  
K Rohde ◽  
NA Watson ◽  
A Faubel
Keyword(s):  
Extracellular Matrix ◽  
Single Cell ◽  
Basal Lamina ◽  
Dense Material ◽  
Undescribed Species ◽  
Single Row ◽  
Longitudinal Ribs ◽  
Capillary Walls

The epidermis of an undescribed species of Luridae possesses many large cavities filled with a medium-dense material, intraepidermal nuclei, glandular ducts, cilia with vertical and horizontal rootlets, surface microvilli, and a thick basal lamina. Cilia have narrow tips, the peripheral axonemal doublets lose one of the microtubules and, finally, whole doublets are lost near the tip. Flame bulbs have a single row of longitudinal ribs containing microtubules and connected by a 'membrane' apparently of extracellular matrix; cilia of flame bulbs possess cross-striated rootlets, and capillary walls are smooth. The nucleus of the protonephridium was observed near the tip of the flame bulb, along the capillary. It is not clear whether one perikaryon forms more than one flame bulb. The structure of the epidermal ciliary rootlets, the presence of intraepidermal nuclei, and flame bulbs composed of a single row of longitudinal ribs containing microtubules formed by a single cell are typical rhabdocoel characteristics.

The ultrastructure of the cuticle of the nematode Syphacia obvelata (Rudolphi, 1802). II. Modifications of the cuticle in the head end

1973 ◽  
Vol 51 (2) ◽  
pp. 197-202 ◽  
Author(s):  
T. A. Dick ◽  
K. A. Wright
Keyword(s):  
Body Wall ◽  
Buccal Capsule ◽  
The Body ◽  
Head Region ◽  
Limited Region ◽  
Structural Role ◽  
Mouth Cavity ◽  
Median Zone ◽  
Syphacia Obvelata ◽  
Somatic Muscles

The head region of the pinworm Syphacia obvelata (Rudolphi, 1802) has been examined to determine the nature of modification of the cuticle responsible for, or associated with, lips and buccal capsule, cephalic papillae and amphids, cephalic inflations, and cervical alae. The median zone of the cuticle was found to be the most modified and variation in the extent and distribution of striated material is compatible with its proposed structural role. The variations found are probably related to compensation for stresses that may develop in the cuticle during the complex movements of the head end. Lips are only inconspicuous expansions of the body wall cuticle, while esophageal cuticle is strikingly different in appearance. It is proposed to refer to all regions of the mouth cavity bounded by both the lips and esophagus as the buccal capsule while only the limited region bounded by body wall cuticle may be referred to as stoma. A mechanism involving three groups of intrahypodermal cytoskeletal filaments attached to the tips of somatic muscles, esophagus, and cuticle is proposed to move the lips.

scholarly journals Histology of the LarvalNeodiprion abietis(Hymenoptera: Diprionidae) Digestive Tract

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Christopher J. Lucarotti ◽  
Beatrixe H. Whittome-Waygood ◽  
David B. Levin
Keyword(s):  
Epithelial Cells ◽  
Basal Lamina ◽  
Alimentary Canal ◽  
Single Layer ◽  
Malpighian Tubules ◽  
The Other ◽  
Peritrophic Membrane ◽  
Straight Tube ◽  
Neodiprion Abietis ◽  
Regenerative Cells

The alimentary canal ofNeodiprion abietislarvae is a straight tube divided into foregut, midgut, and hindgut. Posterior to the mouth, the foregut is further divided into the pharynx, esophagus (crop), and proventriculus, all of which are lined with cuticle. A pair of muscular, chitin-lined pouches branch off the anterior foregut and lie lateral to the alimentary canal. Gastric caeca are located at the anterior end of the midgut, where the peritrophic membrane is formed and was observed throughout the midgut. A single layer of midgut columnar epithelial cells abuts on the basal lamina at one end with microvilli extending into the gut lumen at the other. Nidi of regenerative cells were observed between columnar epithelial cells at the basal lamina. Malpighian tubules are attached to the posterior end of the midgut. The hindgut consists of the pylorus, a muscular ileum connecting to a bulbous rectum, which then opens to the anus.

Ultrastructure of the tegument of the metacercaria ofTimoniella imbutiforme

2000 ◽  
Vol 74 (1) ◽  
pp. 57-66 ◽  
Author(s):  
H.E.M. El-Darsh ◽  
P.J. Whitfield
Keyword(s):  
Basal Lamina ◽  
Larval Stage ◽  
The Body ◽  
Secretory Body ◽  
Gland Cells ◽  
Normal Configuration ◽  
Secretory Gland ◽  
Tegumental Syncytium ◽  
Somatic Muscles ◽  
Sensory Endings

AbstractThe spinous body tegument of the metacercaria ofTimoniella imbutiforme(Molin, 1859) is described in detail and found to comprise an outer tegumental syncytium connected to subjacently situated subtegumentary ‘cells’. There are four types of secretory bodies in the outer syncytial layer as well as serrated overlapping spines and mitochondria. The subtegumentary ‘cells’ are characterized by the presence of four secretory body types as well as giant bodies which may be involved in the elaboration of the secretory bodies or spine material. The normal configuration of the somatic muscles ofT. imbutiformeshow that the muscular machinery necessary for activity once the larval stage becomes excysted is already in place. The sensory endings are found to be of the uniciliate type occurring in groups of up to eight in raised domes distributed over the body. Secretory gland cells are numerous and possess long ducts connected to the basal lamina of the outer syncytial layer via septate desmosomes.

B. The Non-Linear Calculations for Pulsating Stars

1967 ◽  
Vol 28 ◽  
pp. 105-176
Author(s):  
Robert F. Christy
Keyword(s):  
Major Part ◽  
Afternoon Session ◽  
Discussion Session ◽  
Pulsating Stars ◽  
Fourth Symposium ◽  
Non Linear ◽  
Considerable Discussion ◽  
Informal Approach ◽  
Preceding Session

(Ed. note: The custom in these Symposia has been to have a summary-introductory presentation which lasts about 1 to 1.5 hours, during which discussion from the floor is minor and usually directed at technical clarification. The remainder of the session is then devoted to discussion of the whole subject, oriented around the summary-introduction. The preceding session, I-A, at Nice, followed this pattern. Christy suggested that we might experiment in his presentation with a much more informal approach, allowing considerable discussion of the points raised in the summary-introduction during its presentation, with perhaps the entire morning spent in this way, reserving the afternoon session for discussion only. At Varenna, in the Fourth Symposium, several of the summaryintroductory papers presented from the astronomical viewpoint had been so full of concepts unfamiliar to a number of the aerodynamicists-physicists present, that a major part of the following discussion session had been devoted to simply clarifying concepts and then repeating a considerable amount of what had been summarized. So, always looking for alternatives which help to increase the understanding between the different disciplines by introducing clarification of concept as expeditiously as possible, we tried Christy's suggestion. Thus you will find the pattern of the following different from that in session I-A. I am much indebted to Christy for extensive collaboration in editing the resulting combined presentation and discussion. As always, however, I have taken upon myself the responsibility for the final editing, and so all shortcomings are on my head.)

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

A Comparison of the Ultrastructural Morphology of Hepatic Necrosis in BDF1 Mice

1981 ◽  
Vol 39 ◽  
pp. 586-587
Author(s):  
Becky Jackson
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Preliminary Investigation ◽  
Hepatic Necrosis ◽  
Hepatic Tissue ◽  
Pronounced Increase ◽  
Glycogen Store ◽  
Ultrastructural Morphology ◽  
Mitochondrial Integrity ◽  
Glycogen Stores

Preliminary investigation has indicated similarity in hepatic ultrastructural morphology in nutritional deprivation, and cyanide induced hepatic necrosis. Analysis of hepatic tissue has indicated disruption of intracellular membranes, specifically, reduction in rough endoplasmic reticulum (RER) mitochondrial integrity, and glycogen stores. An increase in smooth endoplasmic reticulum (SER) portion was observed.To further investigate the apparent equivalence of necrotic morphology, ultrastructura1ly, BDF1 mice were subjected to senescence, nutritional deprevation, potassium cyanide (KCN) induced toxemia, and acetaminophen induced toxemia. Controls were utilized to ellucidate non-necrotic hepatocellular normals. U1trastructura1 investigation of controls (Fig. 1) shows densely granular RER, abundant glycogen stores, and morphologically normal mitochondria. Subjects with acetaminophen induced necrosis exhibit reduced normal RER with increased levels of dialated, vesicular RER in apparent conversion to SER (Fig. 2), loss of mitochondrial integrity, and glycogen store reduction. Senescent subjects exhibit a pronounced increase in SER and loss of glycogen store. (Fig. 3). Investigation of the senescent SER at high magnification (Fig. 5) indicates that the SER is arising from degranulating and vesiculating RER.

Ultrastructural morphology of nontumorous lactotrophs in human pituitaries exposed to high prolactin levels

1987 ◽  
Vol 45 ◽  
pp. 896-897
Author(s):  
S. Jalalah ◽  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Anterior Pituitary ◽  
Secretory Activity ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Endocrine Activity ◽  
Hormone Synthesis ◽  
Anterior Pituitary Hormones ◽  
Negative Feedback Mechanism ◽  
Ultrastructural Morphology ◽  
Transmission Electron

Lactotrophs, as many other endocrine cells, change their morphology in response to factors influencing their secretory activity. Secretion of prolactin (PRL) from lactotrophs, like that of other anterior pituitary hormones, is under the control of the hypothalamus. Unlike most anterior pituitary hormones, PRL has no apparent target gland which could modulate the endocrine activity of lactotrophs. It is generally agreed that PRL regulates its own release from lactotrophs via the short loop negative feedback mechanism exerted at the level of the hypothalamus or the pituitary. Accordingly, ultrastructural morphology of lactotrophs is not constant; it is changing in response to high PRL levels showing signs of suppressed hormone synthesis and secretion.By transmission electron microscopy and morphometry, we have studied the morphology of lactotrophs in nontumorous (NT) portions of 7 human pituitaries containing PRL-secreting adenoma; these lactotrophs were exposed to abnormally high PRL levels.

Filipino Guest Workers, Gender Segregation, and the Changing Social/Labor-Scape in the Kingdom of Saudi Arabia

2019 ◽  
Vol 16 (4) ◽  
pp. 503-512
Author(s):  
Simeon S. Magliveras
Keyword(s):  
Saudi Arabia ◽  
Migrant Workers ◽  
Major Part ◽  
Gender Segregation ◽  
Guest Workers ◽  
Kingdom Of Saudi Arabia ◽  
Gcc Countries ◽  
Overseas Filipino Workers ◽  
Dress Codes ◽  
Social Labor

Filipinos are a major part of the workforce in the Kingdom of Saudi Arabia with a population of almost one million. This article investigates the effects of gender segregation on Filipino workers and how they navigate their lives through systems imposed on them. In particular, it examines the Kafala system (administrative sponsoring system) used for recruiting migrant workers for GCC countries. This article suggests that contrary beliefs about gender segregation and dress codes, Filipinas found it empowering. However, this article also concludes that gender segregation and dress codes also lead to isolation and loneliness. In addition, it is concluded that the fate and contentment of the overseas Filipino workers are directly dependent on who sponsors them.

Swim bladder mycosis in farmed rainbow trout Oncorhynchus mykiss caused by Phoma herbarum and experimental verification of pathogenicity

2020 ◽  
Vol 138 ◽  
pp. 237-246 ◽  
Author(s):  
J Řehulka ◽  
A Kubátová ◽  
V Hubka
Keyword(s):  
Rainbow Trout ◽  
Histopathological Examination ◽  
Periodic Acid ◽  
Bladder Wall ◽  
Swim Bladder ◽  
Cell Reactivity ◽  
Periodic Acid Schiff ◽  
Posterior Portion ◽  
Hepatic Congestion ◽  
Phoma Herbarum

In this study, spontaneous swim bladder mycosis was documented in a farmed fingerling rainbow trout from a raceway culture system. At necropsy, the gross lesions included a thickened swim bladder wall, and the posterior portion of the swim bladder was enlarged due to massive hyperplasia of muscle. A microscopic wet mount examination of the swim bladder contents revealed abundant septate hyphae, and histopathological examination showed periodic acid-Schiff-positive mycelia in the lumen and wall of the swim bladder. Histopathological examination of the thickened posterior swim bladder revealed muscle hyperplasia with expansion by inflammatory cells. The causative agent was identified as Phoma herbarum through morphological analysis and DNA sequencing. The disease was reproduced in rainbow trout fingerlings using intraperitoneal injection of a spore suspension. Necropsy in dead and moribund fish revealed extensive congestion and haemorrhages in the serosa of visceral organs and in liver and abdominal serosanguinous fluid. Histopathological examination showed severe hepatic congestion, sinusoidal dilatation, Kupffer cell reactivity, leukostasis and degenerative changes. Fungi were disseminated to the liver, pyloric caeca, kidney, spleen and heart. Although infections caused by Phoma spp. have been repeatedly reported in fish, species identification has been hampered by extensive taxonomic changes. The results of this study confirmed the pathogenicity of P. herbarum in salmonids by using a reliably identified strain during experimental fish infection and provides new knowledge regarding the course of infection.

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