Nematode morphogenesis: fine structure of the cuticle of each stage of the nematode, Panagrellus silusiae (de Man 1913) Goodey 1945

1968 ◽  
Vol 46 (5) ◽  
pp. 1019-1022 ◽  
Author(s):  
M. R. Samoiloff ◽  
J. Pasternak
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Outer Region ◽  
Free Living ◽  
Larval Stages ◽  
Transparent Layer ◽  
Layer 2 ◽  
Free Living Nematode ◽  
Inner Region ◽  
De Man

The fine structure of the cuticle of each of the five stages of the free-living nematode Panagrellus silusiae (de Man 1913) Goodey 1945 has been examined. The cuticle plan is made up of a few regions: (1) an outer region (~350 Å) which consists of three layers: a thin outer layer, an electron transparent layer, and a thin but diffuse inner layer; (2) an inner region which has virtually no resolvable substructure other than a striated layer. This layer is not usually seen in the early stages of development but is readily apparent in the L4 and adult stages. The pattern of the cuticle is the same for each stage.The lateral fields—alae—reveal a definite differentiation during the life cycle; in the larval stages they are mere bulges but in the adults they take on a distinct four-lobed shape. The cuticle lining the pharynx consists of two regions, and there is never a striated band present nor does the cuticle increase in width during nematode growth.The interchordal hypodermis is devoid of endoplasmic reticulum, Golgi material, and mitochondria, but in some regions glycogen is found.

Nematode morphogenesis: fine structure of the molting cycles in Panagrellus silusiae (de Man 1913) Goodey 1945

1969 ◽  
Vol 47 (4) ◽  
pp. 639-643 ◽  
Author(s):  
M. R. Samoiloff ◽  
J. Pasternak
Keyword(s):  
Protein Synthesis ◽  
Fine Structure ◽  
Adult Female ◽  
Adult Male ◽  
Early Stage ◽  
Free Living ◽  
Microscopic Evidence ◽  
Molting Process ◽  
Free Living Nematode ◽  
De Man

The mode of formation of a new cuticle in the free-living nematode Panagrellus silusiae is similar at each of the three postpartum molts. Molting begins with the appearance of filaments adjacent to the hypodermis. The new cuticle accumulates material and lacks organization during the early stage of the molt. The edge of the new cuticle adjacent to the old cuticle is composed of an amorphous row of particles and a filamentous region abuts the hypodermis. Eventually, a complete cuticle is produced beneath the preexisting one.The shedding of the old cuticle varies in different molts. In the larval molts (L2 to L3 and L3 to L4) and the molt to the adult female the cuticle is discarded piecemeal. During the molt to the adult male the old cuticle splits and is shed as a single piece.Before completion of ecdysis in the final female molt, the new cuticle folds extensively. This folding does not occur during any other molt.Resorption of the old cuticle is never observed. There is no microscopic evidence of protein synthesis in the interchordal hypodermis during the molting process.

Ultrastructure and cleavage of chlamydospore chains of Thielaviopsis basicola

1970 ◽  
Vol 48 (12) ◽  
pp. 2305-2308 ◽  
Author(s):  
Christos Christias ◽  
Kenneth F. Baker
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Germ Tube ◽  
Outer Region ◽  
Thielaviopsis Basicola ◽  
Thin Electron ◽  
Ultra Thin Section ◽  
Inner Region ◽  
Septal Pores

Electron microscopy revealed that numerous spherical or ellipsoidal globules of reserve nutrient material fill the chlamydospore cells, with cytoplasm as a thin film between these globules. The basal cell of the chain is not a chlamydospore; it is filled with cytoplasm and does not contain these globules. Its plasma membrane, nucleus, mitochondria, lomasomes, and endoplasmic reticulum are evident in ultra-thin section. The walls of chlamydospore cells are thick and without distinct layers, except for an electron-dense outer region and a more electron-transparent inner region. Chlamydospore cells in the chain are separated by a very thin electron-transparent binding layer. A thin two-layered envelope surrounds the entire chain. When chlamydospore chains are treated with chitinase, this envelope remains attached around single separated cells, rather than dissolving away. Cytoplasm of cells in the chain is continuous through septal pores. The end walls of the cells become the opercula after the cells are freed from the chain. The germ tube always emerges at the side where the operculum opens, never through the septal pore.

Studies on Dracunculus medinensis (Linnaeus) III. Structure of the Phasmids in the First-Stage Larva

1973 ◽  
Vol 47 (1) ◽  
pp. 27-33 ◽  
Author(s):  
R. Muller ◽  
D.S. Ellis
Keyword(s):  
Endoplasmic Reticulum ◽  
Single Cell ◽  
Outer Region ◽  
Stage Larva ◽  
Lateral Nerve ◽  
Acid Mucopolysaccharides ◽  
Nerve Bundles ◽  
Inner Region

The phasmids of the first-stage larva of Dracunculus medinensis were paired, each consisting of a single cell with a lumen connected to the exterior by a closable duct. The cell consisted of an outer region filled with mitochondria and an inner region consisting of endoplasmic reticulum bordering the lumen, whose inner surfaces was supported by a fibrillar framework. There were a pair of cilia projecting into the lumen of each cell and two nerve bundles at the base in direct continuity with a branch of the lateral nerve. The lumen of the phasmidial cell contained acid mucopolysaccharides and esterases.

Effects of cyclohexamide and hydroxyurea on mating behavior and its development in the free-living nematode Panagrellus silusiae (de Man 1913) Goodey, 1945

1972 ◽  
Vol 50 (3) ◽  
pp. 333-336 ◽  
Author(s):  
Ronald Cheng ◽  
M. R. Samoiloff
Keyword(s):  
Reproductive System ◽  
Sexual Attraction ◽  
Copulatory Behavior ◽  
Postembryonic Development ◽  
Free Living ◽  
Complete Development ◽  
Adult Females ◽  
Free Living Nematode ◽  
Attraction System ◽  
De Man

Females of the free-living dioecious nematode Panagrellus silusiae that have undergone postembryonic development in hydroxyurea do not attract males, and treated males do not respond to normal females. Nematodes placed in hydroxyurea as adults have normal gonads and retain the sexual attraction system. Hydroxyurea has no effect upon copulatory behavior of adult animals. Treatment of adult females with actidione stops production of attractant, although production resumes within 24 h after removal of the females from actidione. Actidione treatment of males has no effect upon the response to attractant by males or on copulation. It is proposed that sexual attraction depends on complete development of the reproductive system, but that copulation does not.

scholarly journals Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1203-1215 ◽  
Author(s):  
VICTORIA GILLAN ◽  
EILEEN DEVANEY
Keyword(s):  
Life Cycle ◽  
Heat Shock Protein 90 ◽  
Ecological Niches ◽  
Actual Number ◽  
Host Organism ◽  
Free Living ◽  
Parasitic Species ◽  
Free Living Nematode ◽  
Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

An Electron Microscope study of a Small Free-living Amoeba (Hartmanella astronyxis)

1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Layered Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Honeycomb Structure ◽  
Free Living ◽  
Free Living Amoeba

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.

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