The fine structure of the zoospore of Sorochytrium milnesiophthora

1990 ◽  
Vol 68 (9) ◽  
pp. 1968-1977 ◽  
Author(s):  
Ruth Ann Dewel ◽  
William C. Dewel
Keyword(s):  
Fine Structure ◽  
Key Words ◽  
Single Complex ◽  
Peripheral Cytoplasm

As a part of an investigation of Sorochytrium milnesiophthora Dewel, a parasite of the tardigrade Milnesium tardigradum, the ultrastructure of the zoospore was examined. In overall organization, the zoospore is similar to the spores of the Blastocladiales. The nucleus is conical and located in the posterior third of the cell. A large nuclear cap is anterior to the nucleus. In an arrangement unique for members of the Blastocladiales, the nuclear cap contains, in addition to aggregated ribosomes, a single complex mitochondrion, lipid globules, and microbodies. Portions of the nuclear cap extend posteriorly and partially surround the kinetosome. The kinetosome has nine anterior rootletlike projections that link it to the mitochondrion and nine posterior kinetosomal props that attach it to the plasmalemma. It lies at the base of the nucleus as an anchor for a single, posterior whiplash flagellum. A nonkinetosomal centriole is positioned at an approximate 45° angle to the kinetosome. In the peripheral cytoplasm, there are three structurally distinct types of inclusions hypothesized to be adhesion vesicles, phosphate storage bodies, and gamma-like particles. Therefore, the ultrastructure of the zoospore supports the inclusion of this fungus in the Blastocladiales. Key words: Blastocladiales, zoospore, ultrastructure.

scholarly journals THE CYTOPLASMIC FINE STRUCTURE OF THE DIATOM, NITZSCHIA PALEA

1963 ◽  
Vol 18 (2) ◽  
pp. 429-440 ◽  
Author(s):  
Ryan W. Drum
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Electron Microscope ◽  
Hydrofluoric Acid ◽  
Oil Bodies ◽  
Oil Droplets ◽  
Pennate Diatom ◽  
Thin Sections ◽  
Nitzschia Palea ◽  
Peripheral Cytoplasm

The cytoplasmic fine structure of the motile, pennate diatom, Nitzschia palea was studied in thin sections viewed in the electron microscope. The cells were fixed in OsO4, embedded in methacrylate, and immersed in 10 per cent hydrofluoric acid (HF) for 36 to 40 hours to remove the siliceous cell wall prior to sectioning. The HF treatment did not cause any obvious cytoplasmic damage. The dictyosome complex is perinuclear, and located only in the central cytoplasm. Mitochondria are sparse in the central cytoplasm, but abundant in the peripheral cytoplasm, and fill many of the transvacuolar cytoplasmic strands. Characteristic, amorphous oil bodies fill certain cytoplasmic strands and probably are not leucosin. The pyrenoid appears to be membrane limited, and oil droplets are found adjacent to the pyrenoid. The pyrenoid of another diatom, Cymbella affinis, is also membrane-limited. The membrane limiting the pyrenoid may be a composite of the terminal portions of chloroplast discs, facilitating rapid movement of photosynthate into the pyrenoid matrix, where the characteristic oil droplets may be formed. Carinal fibrils are found singly in each carinal pore, and may be involved in the locomotion of Nitzschia palea.

Fine Structure of the Hindgut of Armadillidium Vulgare

1971 ◽  
Vol 29 ◽  
pp. 414-415
Author(s):  
Laura Herold ◽  
G. M. Vernon ◽  
E. R. Witkus
Keyword(s):  
Fine Structure ◽  
Epithelial Cell ◽  
Cell Layer ◽  
The Other ◽  
Apical Region ◽  
Luminal Surface ◽  
Intercellular Spaces ◽  
Armadillidium Vulgare ◽  
Epithelial Cell Layer ◽  
Peripheral Cytoplasm

An ultrastructural study of the hepatopancreatic ducts and the hindgut of the terrestrial isopod, Armadillidium vulgare, reveals the presence of a single epithelial cell layer lined with cuticle. The cells of the duct lack the microvilli characteristic of the hepatopancreas and exhibit fewer apical infoldings than the cells of the hindgut. Basal infoldings, on the other hand, are common and relatively deep. Mitochondria are more abundant in the apical region of the cell than in the basal part. Bands of microtubules are present in the peripheral cytoplasm, and most of the microtubules run vertically in the cell from the luminal surface to the base (see fig. 1). Single membrane bounded vesicles of varying size were observed. These bodies contain moderately electron dense granular material. At the luminal surface the lateral membranes of adjacent cells are linked together by septate desmosomes. From the septate desmosome to the base of the cell there are relatively large intercellular spaces alternating with intermediate junctions or zona adherens.

scholarly journals ON THE FINE STRUCTURE OF THE CAMBIUM OF FRAXINUS AMERICANA L

1966 ◽  
Vol 31 (1) ◽  
pp. 79-93 ◽  
Author(s):  
Lalit M. Srivastava
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Osmium Tetroxide ◽  
Coated Vesicles ◽  
Fraxinus Americana ◽  
Parenchyma Cells ◽  
Rough Er ◽  
Cambial Cells ◽  
Peripheral Cytoplasm

The fine structure of ash cambium was studied after glutaraldehyde-osmium tetroxide fixation. The fusiform and ray initials are essentially alike, and both have the basic complement of organelles and membranes typical of parenchyma cells. The varied behavior of the two types of initials and the role of cambium in oriented production of the xylem and phloem are still unexplained phenomena. Actively growing cambial cells are highly vacuolate. They are rich in endoplasmic reticulum of the rough cisternal form, ribosomes, dictyosomes, and coated vesicles. Microtubules are present in the peripheral cytoplasm. The plasmalemma appears to be continuous with the endoplasmic reticulum and produces coated vesicles as well as micropinocytotic vesicles with smooth surfaces. The plastids have varying amounts of an intralamellar inclusion which may be a lipoprotein. The quiescent cambium is deficient in rough ER and coated vesicles and has certain structures which may be condensed proteins.

The fine structure of Leucocytozoon simondi. V. The oocyst

1972 ◽  
Vol 50 (6) ◽  
pp. 707-711 ◽  
Author(s):  
Sherwin S. Desser
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Basal Lamina ◽  
Central Core ◽  
Granular Endoplasmic Reticulum ◽  
Midgut Epithelium ◽  
Stage Of Development ◽  
Peripheral Cytoplasm

Following penetration through the midgut epithelium of Simulium rugglesi, ookinetes of Leucocytezoon simondi round up beneath the basal lamina and transform into young oocysts. These spherical, walled structures contain a large central core of crystalloid material. Dividing nuclei are seen in the peripheral cytoplasm, which is characterized by several concentric layers of granular endoplasmic reticulum. In a succeeding stage of development the trilaminar plasma membrane appears intermittently doubled, and bud-like outgrowths occur in these thickened areas. At this stage the crystalloid material is dispersed throughout the cytoplasm. A nucleus, an elongate mitochondrion, and some crystalloid material move into each forming sporozoite, which continues to grow at the expense of the residual cytoplasm.

Ultrastructural organization of Rhizophlyctis harderi zoospores and redefinition of the type 1 microbody – lipid globule complex

1992 ◽  
Vol 70 (4) ◽  
pp. 750-761 ◽  
Author(s):  
Martha J. Powell ◽  
Sonali Roychoudhury
Keyword(s):  
Fine Structure ◽  
Three Dimensional ◽  
Ultrastructural Organization ◽  
Serial Sections ◽  
Dense Cores ◽  
Lipid Globule ◽  
Computer Aided ◽  
Glycogen Particles ◽  
Peripheral Cytoplasm

Because ultrastructural features of zoospores are considered primary characters in Chytridiomycete systematics, computer-aided three-dimensional reconstructions of serial sections were used to analyze zoospore fine structure of Rhizophlyctis harderi, a questionable member of the genus Rhizophlyctis. A secondary centriole was parallel to the kinetosome, but the nucleus was not structurally or spatially associated with the kinetosomes. Mitochondria and cisternae associated with vesicles bounded a ribosomal aggregation in which the nucleus was partially embedded. The peripheral cytoplasm between the plasma membrane and ribosomal aggregation contained α-glycogen particles, vacuoles with osmiophilic globules, vesicles with clear matrices, and vesicles with electron-dense cores. A new, compound form of microbody – lipid globule complex (MLC) was identified. This type of MLC incorporated posteriorly located lipid globules associated with rumposomes and anteriorly located lipid globules associated with simple cisternae, microbodies, and highly branched mitochondria. Based on these and other recent observations, the concept of the type 1 MLC was redefined. Sources for variation in ultrastructural features of zoospores are discussed. Zoospore ultrastructure of R. harderi is different from that described for other chytrid zoospores. Key words: Chytridiomycetes, microbody – lipid globule complex, Rhizophlyctis, taxonomy, ultrastructure, zoospore.

High-resolution terahertz spectrum of CH2 — Low J rotational transitions near 2 THz

2004 ◽  
Vol 82 (6) ◽  
pp. 676-683 ◽  
Author(s):  
S Brünken ◽  
E A Michael ◽  
F Lewen ◽  
Th. Giesen ◽  
H Ozeki ◽  
...  
Keyword(s):  
Fine Structure ◽  
High Resolution ◽  
Key Words ◽  
Hyperfine Structure ◽  
Electronic State ◽  
Rotational Transition ◽  
The Other ◽  
Terahertz Spectrum ◽  
Global Fit ◽  
Rotational Transitions

The methylene radical (CH2) was very important to Gerhard Herzberg. We have carried out high-resolution spectroscopic measurements on two energetically low-lying, pure rotational transitions of methylene in its ground vibrational–electronic state at frequencies near 2 THz. One of the transitions — the NKaKc = 211 ← 202 multiplet — belongs to ortho-CH2 and is centered at 1.954 THz. The other rotational transition — the NKaKc = 110 ← 101 multiplet — belongs to para-CH2 and is centered at 1.915 THz. Since the ground electronic state of methylene has 3B1 symmetry, the rotational transitions are split into three fine-structure components, while the ortho transitions are split additionally by hyperfine structure. In total, we have measured 29 new lines, six for the para transition and the remainder for the ortho transition. The newly measured lines can be added to high-resolution spectral data obtained by ourselves and others at lower frequencies. Progress towards a global fit is discussed. Key words: spectroscopy, THz frequencies, radicals, methylene, interstellar medium.

Fine structure of ascosporogenesis in Ceratocystiopsis proteae

1993 ◽  
Vol 71 (9) ◽  
pp. 1212-1218 ◽  
Author(s):  
P. W. J. Van Wyk ◽  
M. J. Wingfield
Keyword(s):  
Fine Structure ◽  
Key Words ◽  
Morphological Characteristics ◽  
Taxonomic Revision ◽  
Wall Layer ◽  
Microscopic Studies

The development and ultrastructure of the ascoma, asci, and ascospores in Ceratocystiopsis proteae were studied and compared with that of other genera in Ceratocystis sensu lato. Ascospore delimitation commenced with the formation of double delimiting membranes in the ascus as is true in other species in Ceratocystis s.l. The ascospore wall developed between these membranes. In contrast with three wall layers observed in other species, only two wall layers were observed in C. proteae. Falcate sheaths previously reported in light-microscopic studies were not observed. The falcate appearance of ascospores may be ascribed to the adherence of a matrix to the outermost wall layer during ascospores release. Differences between this species and others in Ceratocystis s.l. illustrate the problems that can arise from the use of single morphological characteristics in the taxonomy of this group. It is accordingly suggested that the genus Ceratocystiopsis requires taxonomic revision. Key words: Ceratocystiopsis, falcate ascospores, sheaths, centrum.

Fine Structure of Platelet Interaction with a New Microcrystalline Collagen Preparation

1974 ◽  
Vol 32 ◽  
pp. 58-59
Author(s):  
W. H. Zucker ◽  
R. G. Mason
Keyword(s):  
Fine Structure ◽  
Platelet Aggregation ◽  
Hydrochloric Acid ◽  
Whole Blood ◽  
Platelet Adhesion ◽  
Hemostatic Agent ◽  
Native Collagen ◽  
Fibrillar Morphology ◽  
Clinical Interest ◽  
New Form

Platelet adhesion initiates platelet aggregation and is an important component of the hemostatic process. Since the development of a new form of collagen as a topical hemostatic agent is of both basic and clinical interest, an ultrastructural and hematologic study of the interaction of platelets with the microcrystalline collagen preparation was undertaken.In this study, whole blood anticoagulated with EDTA was used in order to inhibit aggregation and permit study of platelet adhesion to collagen as an isolated event. The microcrystalline collagen was prepared from bovine dermal corium; milling was with sharp blades. The preparation consists of partial hydrochloric acid amine collagen salts and retains much of the fibrillar morphology of native collagen.

Pituitary Follicular Cells: Their Origin, Possible Function and Fate

1974 ◽  
Vol 32 ◽  
pp. 34-35
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
G. Penz ◽  
C. Ezrin
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Follicular Cells ◽  
Human Pituitary ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Junctional Complexes

Follicular structures, in the rat pituitary, composed of cells joined by junctional complexes and possessing few organelles and few, if any, secretory granules, were first described by Farquhar in 1957. Cells of the same description have since been observed in several species including man. The importance of these cells, however, remains obscure. While studying human pituitary glands, we have observed wide variations in the fine structure of follicular cells which may lead to a better understanding of their morphogenesis and significance.

Ultrastructure and Staining of Developing Elastic Tissue

1971 ◽  
Vol 29 ◽  
pp. 244-245
Author(s):  
E. N. Albert
Keyword(s):  
Fine Structure ◽  
Phosphotungstic Acid ◽  
Staining Method ◽  
Rat Aorta ◽  
Uranyl Acetate ◽  
The Other ◽  
Elastic Fibers ◽  
Elastic Tissue ◽  
Lead Citrate ◽  
New Born

Silver tetraphenylporphine sulfonate (Ag-TPPS) was synthesized in this laboratory and used as an electron dense stain for elastic tissue (Fig 1). The procedures for the synthesis of tetraphenylporphine sulfonate and the staining method for mature elastic tissue have been described previously.The fine structure of developing elastic tissue was observed in fetal and new born rat aorta using tetraphenylporphine sulfonate, phosphotungstic acid, uranyl acetate and lead citrate. The newly forming elastica consisted of two morphologically distinct components. These were a central amorphous and a peripheral fibrous. The ratio of the central amorphous and the peripheral fibrillar portion changed in favor of the former with increasing age.It was also observed that the staining properties of the two components were entirely different. The peripheral fibrous component stained with uranyl acetate and/or lead citrate while the central amorphous portion demonstrated no affinity for these stains. On the other hand, the central amorphous portion of developing elastic fibers stained vigorously with silver tetraphenylporphine sulfonate, while the fibrillar part did not (compare figs 2, 3, 4). Based upon the above observations it is proposed that developing elastica consists of two components that are morphologically and chemically different.

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