Ultrastructural investigation of the secondary excretory system in different stages of the procercoid of Triaenophorus nodulosus (Cestoda, Pseudophyllidea, Triaenophoridae)

Parasitology ◽  
1998 ◽  
Vol 116 (4) ◽  
pp. 373-381 ◽  
Author(s):  
J. V. KORNEVA ◽  
B. I. KUPERMAN ◽  
V. G. DAVYDOV
Keyword(s):  
Excretory System ◽  
Ultrastructural Investigation ◽  
Second Stage ◽  
Undifferentiated Cells ◽  
Excretory Canals ◽  
Triaenophorus Nodulosus

The formation of the definitive procercoid excretory system of the pseudophyllidean cestode Triaenophorus nodulosus has been investigated. This process can be divided into 3 main stages. In the first stage, active autophagic processes lead to the formation of intracellular excretory canals. In the second stage, the process of the autolysis is enhanced and the system of intercellular lacunae functioning as an excretory system is formed. A definitive excretory system of the procercoid forms at the next stage, by means of the migration and proliferation of undifferentiated cells replacing the lacunar system.

Memoirs: The Enteronephric Type of Nephridial System in the Genus Tonoscolex (Gates)

1941 ◽  
Vol s2-82 (327) ◽  
pp. 443-466
Author(s):  
KARM NARAYAN BAHL
Keyword(s):  
Body Wall ◽  
Intermediate Stage ◽  
The Body ◽  
Excretory System ◽  
Excretory Canals

1. The ‘enteronephric’ type of nephridial system, previously described by the author in Pheretima, Lampito, and Woodwardiella (Nellogaster), has now been shown to characterize the genus Tonoscolex as well. It seems that this type of excretory system is widely distributed in the subfamily Megascolecinae. 2. The nephridia are of three kinds: the enteronephric septal nephridia, the exonephric integumentary nephridia, and the enteroriephric pharyngeal nephridia. There are twenty-four to thirty septal nephridia in each of those segments where they are best developed, these nephridia being much larger in size than the septal ruicronephridia of Pheretima. The pharyngeal nephridia form a cylindrical bunch around the oesophagus in the sixth segment and open into the pharynx in front by a large number of ducts. The integumentary nephridia are extremely minute and open singly on the body-wall. 3. The elaborate system of septal excretory canals and supraintestinal ducts characteristic of the septal nephridial systems of Pheretima, Lampito, and Woodwardiella, does not exist in Tonoscolex. The system in Tonoscolex is therefore much simpler and probably more primitive, and may represent an intermediate stage between the purely exonephric rneganephridia of Lumbricus and the elaborate enteronephric system of Pheretima, Lampito, and Woodwardiella.

The excretory system of nematodes: structure and ultrastructure of the excretory system of Panagrellus redivivus, Ditylenchus myceliophagus with some observations on D. dipsaci and Heterodera rostochiensis

Parasitology ◽  
1972 ◽  
Vol 64 (2) ◽  
pp. 253-268 ◽  
Author(s):  
H. K. Narang
Keyword(s):  
Secretory Granules ◽  
Anterior Part ◽  
Excretory Duct ◽  
Excretory System ◽  
Second Stage ◽  
Panagrellus Redivivus ◽  
Heterodera Rostochiensis ◽  
The One ◽  
The Right ◽  
Structure And Ultrastructure

The structure and ultrastructure of the excretory system of Panagrellus redivivus, Ditylenchus myceliophagus, D. dipsaci and the second-stage larvae of the Heterodera rostochiensis are described. Panagrellus has two lateral ducts, a median duct and a gland. The two lateral ducts are joined over the anterior part of the oesophageal bulb to form a loop. Anteriorly this loop continues as a median duct, which opens to the exterior in an excretory pit, part of the system lies free in the pseudocoelom. The lumen of the lateral excretory duct and the greater part of the median duct is surrounded by capitate tubules, which open into the lumen of the excretory duct. Capitate tubules develop by the invagination of the hypodermal membranes and lie embedded in thick cytoplasm surrounded by mitochondria. Ensheathed in cell membranes the excretory duct forms an anastomosis in the loop and at three other places along the length of each lateral excretory duct. At these regions there are nerve endings. The excretory gland opens posteriorly into the loop and is full of Golgi complexes, endoplasmic reticulum and secretory granules.In the system of Ditylenchus and the second-stage larva of Heterodera the right lateral duct is absent while the left lateral excretory duct continues anteriorly past the median excretory duct; a true loop is not formed. The median excretory duct lies embedded almost throughout its length in the excretory gland. Capitate tubules are present along the length of the lateral excretory duct, but, unlike Panagrellus, are not present around the median excretory duct. Anastomosis is not formed in the excretory ducts. In other respects the system of the species studied is similar to that of Panagrellus.The capitate tubules form a system of fine microtubules. Their ultrastructure and, particularly, their association with large numbers of mitochondria, is very reminiscent of structures thought to be concerned with an active transport role, related to ionic and osmoregulation in other phyla.The excretory system is almost certainly hypodermal in origin. Differences between the morphology and relations of the median duct of Enoplus (Narang, 1970), on the one hand, and that of the other forms studied suggest that these ducts may have different origins: the presence of separate nuclei in the lateral duct and gland portions of the system would be consistent with this view. It is considered that the two parts may have originated separately and have become joined during evolution. It is also shown that the excretory system of Ditylenchus cannot be derived either from an H-shaped system or from a primitive gland system.I wish to thank Professor C. Ellenby and Mr L. Smith for their helpful criticism.

On Ilisha parthenogenetica, Southwell and Baini Prashad, 1918, from the Pyloric Caeca of a Fish, Hilsa ilisha (Ham. Buch.), and a Comparison with other Plerocercoid Larvae of Cestodes

Parasitology ◽  
1923 ◽  
Vol 15 (2) ◽  
pp. 128-136 ◽  
Author(s):  
W. N. F. Woodland
Keyword(s):  
Life History ◽  
The Body ◽  
Excretory System ◽  
Pyloric Caeca ◽  
Cestode Parasite ◽  
Individual Fish ◽  
The Common ◽  
Excretory Canals ◽  
Sexually Mature ◽  
Systematic Importance

In 1918 Southwell and Baini Prashad1 published a description of an unsegmented Cestode parasite—Ilisha parthenogenetica—which they discovered in the “mesentery” of the common edible Indian Shad, Hilsa ilisha. This minute parasite, according to these authors, “appears to be of very great systematic importance, and…further reproduces itself in a manner not before known amongst the Cestoda.” In justification of these general remarks, they make, among others, the following statements: (1) the parasite, though of the well-known Piestocystis larva type, becomes sexually mature and resides in a cyst formed from the tissues of the mesentery; (2) these cysts are so numerous in every individual fish examined that the mesentery becomes transformed into “a massive liver-like organ in which the various coils of the intestine appeared merely as tubes embedded therein”; (3) though two lateral main excretory canals are described, yet there is no terminal excretory aperture: the excretory system “is closed in all stages of [the parasite's] life-history”; (4) the whole of the parenchyma is “filled up with enormous numbers of minute egg-cells. Besides the eggs, morulae and other higher stages in the development of the young were also present in the intima.” In other words, the egg-cells “develop in the body of the parent to form young worms identical in structure and appearance with the parent”; (5) the young worms “escape through a temporary aperture which is formed in the middle of the rostellum, anteriorly,” and, when the old cyst has been ruptured, they become “scattered in the mesentery, the [new] cyst not having been secreted at this stage.”

Ultrastructural Investigation of Spontaneous Pituitary Adenomas in Aging Sprague-Dawley Rats

1982 ◽  
Vol 40 ◽  
pp. 216-217
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Microscopic Study ◽  
Pituitary Adenomas ◽  
Wistar Rats ◽  
Microscopic Level ◽  
Sprague Dawley ◽  
Prolactin Cells ◽  
Light Microscopic Level ◽  
Ultrastructural Investigation ◽  
Sprague Dawley Rats ◽  
Long Evans

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

Silica Incorporation in the Cell Wall of the Singing Cell of Urtica dioica

1975 ◽  
Vol 33 ◽  
pp. 584-585
Author(s):  
A. E. Sowers ◽  
E. L. Thurston
Keyword(s):  
Cell Wall ◽  
Unique Feature ◽  
Urtica Dioica ◽  
Wall Material ◽  
Pain Response ◽  
Apical Portion ◽  
Ultrastructural Investigation ◽  
Plant Families ◽  
Bulbous Tip

Plant stinging emergences exhibit functional similarities in that they all elicit a pain response upon contact. A stinging emergence consists of an elongated stinging cell and a multicellular pedestal (Fig. 1). A recent ultrastructural investigation of these structures has revealed the ontogeny and morphology of the stinging cells differs in representative genera in the four plant families which possess such structures. A unique feature of the stinging cell of Urtica dioica is the presence of a siliceous cell wall in the apical portion of the cell. This rigid region of the cell wall is responsible for producing the needle-like apparatus which penetrates the skin. The stinging cell differentiates the apical bulbous tip early in development and the cell continues growth by intercalary addition of non-silicified wall material until maturity.The uppermost region of the stinging cell wall is entirely composed of silica (Fig. 2, 3) and upon etching with a 3% solution of HF (5 seconds), the silica is partially removed revealing the wall consisting of individualized silica bodies (Fig. 4, 5).

Observations on the growth of barium bismuth oxide thin films

1992 ◽  
Vol 50 (1) ◽  
pp. 76-77
Author(s):  
M G. Norton ◽  
E.S. Hellman ◽  
E.H. Hartford ◽  
C.B. Carter
Keyword(s):  
Substrate Temperature ◽  
Deposition Process ◽  
Nucleation Layer ◽  
Second Stage ◽  
Device Applications ◽  
High Transition ◽  
Substrate Temperatures ◽  
Oriented Material ◽  
Barium Bismuth ◽  
Superconductor Device

The bismuthates (for example, Ba1-xKxBiO3) represent a class of high transition temperature superconductors. The lack of anisotropy and the long coherence length of the bismuthates makes them technologically interesting for superconductor device applications. To obtain (100) oriented Ba1-xKxBiO3 films on (100) oriented MgO, a two-stage deposition process is utilized. In the first stage the films are nucleated at higher substrate temperatures, without the potassium. This process appears to facilitate the formation of the perovskite (100) orientation on (100) MgO. This nucleation layer is typically between 10 and 50 nm thick. In the second stage, the substrate temperature is reduced and the Ba1-xKxBiO3 is grown. Continued growth of (100) oriented material is possible at the lower substrate temperature.

Second stage of labor in the age of epidural anesthesia

1998 ◽  
Vol 5 (1) ◽  
pp. 171A-171A
Author(s):  
E XENAKIS ◽  
J PIPER ◽  
M MCFARLAND ◽  
C SUITER ◽  
O LANGER
Keyword(s):  
Epidural Anesthesia ◽  
Second Stage Of Labor ◽  
Second Stage

The Gender Typicality of Faces and Its Impact on Visual Processing and on Hiring Decisions

2013 ◽  
Vol 60 (6) ◽  
pp. 444-452 ◽  
Author(s):  
Lisa von Stockhausen ◽  
Sara Koeser ◽  
Sabine Sczesny
Keyword(s):  
Visual Processing ◽  
Past Research ◽  
Visual Exploration ◽  
Facial Appearance ◽  
Leadership Roles ◽  
Hiring Decisions ◽  
Leadership Selection ◽  
Gender Typicality ◽  
Second Stage ◽  
The Feminine

Past research has shown that the gender typicality of applicants’ faces affects leadership selection irrespective of a candidate’s gender: A masculine facial appearance is congruent with masculine-typed leadership roles, thus masculine-looking applicants are hired more certainly than feminine-looking ones. In the present study, we extended this line of research by investigating hiring decisions for both masculine- and feminine-typed professional roles. Furthermore, we used eye tracking to examine the visual exploration of applicants’ portraits. Our results indicate that masculine-looking applicants were favored for the masculine-typed role (leader) and feminine-looking applicants for the feminine-typed role (team member). Eye movement patterns showed that information about gender category and facial appearance was integrated during first fixations of the portraits. Hiring decisions, however, were not based on this initial analysis, but occurred at a second stage, when the portrait was viewed in the context of considering the applicant for a specific job.

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