Asci of the Pezizales. I. The apical apparatus of iodine-positive species

1978 ◽  
Vol 56 (16) ◽  
pp. 1860-1875 ◽  
Author(s):  
Don A. Samuelson
Keyword(s):  
Electron Microscopy ◽  
Positive Reaction ◽  
Light And Electron Microscopy ◽  
The Other ◽  
Reaction Site ◽  
Lower Region

Morphological, developmental, and cytochemical studies on the apical apparatuses of five species, i.e., Peziza succosa, Ascobolus crenulatus, Saccobolus depauperatus, Thecotheus pelletieri, and Iodophanus granulipolaris, were performed with light and electron microscopy. Asci of all species, except A. crenulatus, stain blue in Melzer's reagent. The site of the iodine-positive reaction is believed to be an exogenous mucilaginous coat in P. succosa, S. depauperatus, and T. pelletieri. In I. granulipolaris, the reaction site appears to be the ascal wall. The presence of an annular indentation was found in the ascal tips of all species except I. granulipolaris. A line of dehiscence was found in the lower region of the annular indentation in T. pelletieri and S. depauperatus. The development of the apical apparatuses of all species occurs during and after late ascosporogenesis. The apical apparatus of I. granulipolaris diverged significantly in morphology and cytochemistry from the other species.

Fine Structure of the Eye of a Nudibranch Mollusc, Hermissenda Crassicornis

1967 ◽  
Vol 2 (3) ◽  
pp. 349-358
Author(s):  
R. M. EAKIN ◽  
JANE A. WESTFALL ◽  
M. J. DENNIS
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Optic Nerve ◽  
Light And Electron Microscopy ◽  
The Other ◽  
Sensory Cells ◽  
Nerve Fibres ◽  
Supporting Cells ◽  
Small Bodies ◽  
Receptor Cells

The eye of a nudibranch, Hermissenda crassicornis, was studied by light and electron microscopy. Three kinds of cells were observed: large sensory cells, each bearing at one end an array of microvilli (rhabdomere) and at the other end an axon which leaves the eye by the optic nerve; large pigmented supporting cells; and small epithelial cells, mostly corneal. There are five sensory cells, and the same number of nerve fibres in the optic nerve. The receptor cells contain an abundance of small vesicles, 600-800 Å in diameter. The lens is a spheroidal mass of osmiophilic, finely granular material. A basal lamina and a capsule of connective tissue enclose the eye. In some animals the eye is ‘infected’ with very small bodies, 4-5 µ in diameter, thought to be symbionts.

Ultrastructure of eastern cottonwood clones susceptible or resistant to leaf rust

1987 ◽  
Vol 65 (8) ◽  
pp. 1586-1598 ◽  
Author(s):  
L. Shain ◽  
U. Järlfors
Keyword(s):  
Electron Microscopy ◽  
Leaf Rust ◽  
Light And Electron Microscopy ◽  
Infection Process ◽  
The Other ◽  
Host Cells ◽  
Eastern Cottonwood ◽  
Melampsora Medusae ◽  
Wall Appositions ◽  
Infected Cells

The infection process in four clones of eastern cottonwood susceptible or resistant to leaf rust caused by Melampsora medusae was studied by light and electron microscopy. Infection was initiated by stomatal rather than direct entry. Typical dikaryotic haustoria were observed in all clones within 1 day of inoculation. Some healthy-appearing haustoria were observed in susceptible clones throughout the duration of the study, which was terminated during the initiation of uredial production. Incompatibility was expressed differently in the two resistant clones. In clone St 75, most haustoria and invaded host cells that were observed appeared necrotic within 2 days of inoculation. Cell wall appositions appeared during this time in cells adjoining necrotic host cells. Some infected cells disintegrated within 4 days of inoculation. Affected host cells of clone St 92, on the other hand, plasmolyzed during the first 2 to 3 days after inoculation. Necrotic host cells were not observed in this clone until the 4th day after inoculation. Hyphal ramification and host plasmolysis were extensive at 6 days after inoculation.

Somatic mitosis in Erysiphe graminis hordei

1972 ◽  
Vol 18 (12) ◽  
pp. 1915-1922 ◽  
Author(s):  
W. E. McKeen
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Nuclear Membrane ◽  
Osmium Tetroxide ◽  
Central Body ◽  
Nuclear Division ◽  
Light And Electron Microscopy ◽  
Erysiphe Graminis ◽  
The Other ◽  
Erysiphe Graminis Hordei

Somatic nuclear division in Erysiphe graminis hordei was studied by light and electron microscopy after various fixation and staining procedures. Electron microscopy studies of alcohol – acetic acid fixed material aided in providing an understanding of nuclear division and showing the gross alterations which occurred. Light microscopy indicated that a central body was always present at a specific site on the nuclear membrane in the interphase nucleus and was connected to chromatic spherical bodies. Microtubules were preserved when a short glutaraldehyde – osmium tetroxide fixation was used. Some microtubules extend from plaque to plaque while others terminate in kinetochores. A microtubular spindle, oblique to the nuclear and mildew-cells axes formed within the nuclear membrane. Typical prophases, metaphases, anaphases, and telophases were observed. Then one set of daughter chromatids bypassed the nucleolus which persisted intranuclearly until the daughter nuclei reached their destination, and the other set of daughter chromatids moved to midpoint in the other daughter cell. A narrow corridor, which connected daughter nuclei for some time, was filled mainly with microtubules and probably was the filament which was observed in the nucleus by light microscopy during nuclear division. At least six chromosomes were present in each nucleus.

Unusual macromorphology of the ductuli efferentes and epididymis of the koala (Phascolarctos cinereus)

2000 ◽  
Vol 48 (6) ◽  
pp. 681
Author(s):  
Rachel J. Gibson ◽  
Chris M. Leigh ◽  
William G. Breed
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Secretory Activity ◽  
The Other ◽  
Ciliated Cells ◽  
Phascolarctos Cinereus ◽  
Ductuli Efferentes ◽  
Sds Page ◽  
Marsupial Species ◽  
Electron Lucent

The macromorphology of the ductuli efferentes and epididymis of the koala (Phascolarctos cinereus) was investigated and found to differ from that of other marsupial species that have been described as it comprised four macroscopically distinct lobes. Light and electron microscopy of epithelium of the duct within these lobes showed that there were principal and ciliated cells lining the duct of the first lobe, indicating it to be composed of ductuli efferentes. In the other three lobes, the epithelium contained principal, basal, electron-lucent, and mitochondria-rich cells, showing that these three lobes included the epithelium of the epididymis. The height of this epithelium gradually increased along the duct (contrary to the situation in most other species that have been studied, in which a decrease occurs). Preliminary 1D-SDS PAGE observations of flushes from the caput and cauda epididymides suggested that epididymal proteins were secreted along much of the length of the duct; the greater height of the cauda epithelium may relate to the greater protein synthetic and secretory activity in this region.

The differentiation of mouse gonads in vitro: a light and electron microscopical study

Development ◽  
1986 ◽  
Vol 97 (1) ◽  
pp. 189-199
Author(s):  
Sarah Mackay ◽  
Robert A. Smith
Keyword(s):  
Electron Microscopy ◽  
Culture Medium ◽  
Light And Electron Microscopy ◽  
Calf Serum ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
The Other ◽  
Foetal Calf Serum ◽  
Electron Microscopical

Indifferent urogenital complexes were excised from mouse foetuses assessed by developmental criteria as day 10·5 or 11. After 4 or 6–7 days in culture, complexes were fixed and examined by light and electron microscopy. The effect of culturing sexed complexes in mixed sex groups was investigated. The effect of the presence or absence of foetal calf serum in the culture medium was considered. No evidence of inhibition of one sex by the other was found. Ovaries developed further in cultures than testes.

The Mouse Testis as a Model for the Study of Age Related Fine Structural Changes

1975 ◽  
Vol 33 ◽  
pp. 586-587
Author(s):  
J.E. Johnson ◽  
J. Miquel
Keyword(s):  
Electron Microscopy ◽  
Sertoli Cells ◽  
Structural Changes ◽  
Light And Electron Microscopy ◽  
Interstitial Cells ◽  
Comparative Investigation ◽  
The Other ◽  
Vascular Perfusion ◽  
Dense Bodies ◽  
Age Related

In studying the morphology of aging cells, it is generally concluded that different changes occur in fixed postmitotic cells as compared to those cells which divide actively throughout life. The testis appears to be an excellent model for a comparative investigation of such changes, since it contains some cells which are essentially non-dividing in adulthood (Sertoli cells and interstitial cells) as well as other cells which divide continuously in mature animals (spermatogonia and spermatocytes).We have examined, by light and electron microscopy, the testes of numerous C57BL/6J mice at ages ranging from 3 to 30 months. All tissues were fixed by vascular perfusion with paraformaldehyde and glutaraldehyde mixtures in phosphate buffer.Sertoli cells (Fig. 1) and interstitial cells (Fig. 2) in aging animals contain a large number of dense bodies (presumably lipofuscin). On the other hand, dense bodies are not seen in spermatogonia, spermatocytes or spermatids (Fig. 1).

scholarly journals Micromorphology and Systematic Distribution of Pit Membrane Thickenings in Oleaceae: Tori and Pseudo-Tori

IAWA Journal ◽  
2008 ◽  
Vol 29 (4) ◽  
pp. 409-424 ◽  
Author(s):  
David Rabaey ◽  
Suzy Huysmans ◽  
Frederic Lens ◽  
Erik Smets ◽  
Steven Jansen
Keyword(s):  
Electron Microscopy ◽  
Functional Significance ◽  
New Records ◽  
Light And Electron Microscopy ◽  
Functional Adaptation ◽  
The Other ◽  
General Interest ◽  
Pit Membrane ◽  
The Family ◽  
Structural Differences

Recent studies on the functional significance of pit membranes in water conducting cells have renewed general interest in their micromorphology. At least two types of pit membrane thickenings have been described in angiosperm families, i.e. genuine tori and pseudo-tori. This study explores the distribution and morphology of pit membrane thickenings in 69 species and 23 genera within Oleaceae using light and electron microscopy. Torus-bearing pit membranes are confirmed for Osmanthus, and new records are reported for Chionanthus retusa, Picconia azorica, and P. excelsa, but not for the other species studied of Chionanthus. This infrageneric variation suggests that tori represent a plastic feature that has evolved more than once within the family as the result of functional adaptation to efficient and safe water transport. Pseudo-tori are observed in species of Abeliophyllum, Fontanesia, Forsythia, Jasminum, Ligustrum, Menodora, and Syringa. Based on structural differences, we state that tori and pseudo-tori can be distinguished as non-homologous features.

Morphogenetic analysis of changing cell associations following release of 2-cell and 4-cell mouse embryos from cleavage arrest

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 331-345
Author(s):  
S. J. Kimber ◽  
M. A. H. Surani
Keyword(s):  
Electron Microscopy ◽  
Cell Division ◽  
Light And Electron Microscopy ◽  
Cytochalasin D ◽  
Mouse Embryos ◽  
Fresh Medium ◽  
The Other ◽  
Similar Process ◽  
Serial Sections ◽  
Morphogenetic Analysis

Two-cell and four-cell mouse embryos were cultured in Cytochalasin D (CD) for 40–48 h. They were fixed for light and electron microscopy at various times after washing off the CD. Cleavage-arrested embiyos in CD had well separated blastomeres but by 1 h from washing the embryos had compacted, in most cases without undergoing cell division. By 2 h after release from arrest one blastomere of the 2-cell arrested embryos had become crescent shaped and at 4–5 h the crescent-shaped blastomere had started to spread over the surface of the other rounded blastomere. This process continued until by 16–24 h from explantation to fresh medium one blastomere had almost completely engulfed the other. A similar process occurred in 4-cell arrested and released embryos. At this stage the embryos had accumulated fluid and become blastocyst-like vesicles. In 20% of 2-cell and 4-cell embryos one or two blastomeres underwent one cell division after release from arrest. Serial sections of these embryos lead to the conclusion that one or both progeny of the first cell to divide tended to be engulfed by the later dividing or non-dividing cell(s). These results are discussed in relation to the differentiation of ICM and trophectoderm in blastocysts.

On the ultrastructure of the polycercus larva of Paricterotaenia paradoxa (Cestoda: Cyclophyllidea)

1974 ◽  
Vol 52 (11) ◽  
pp. 1397-1405 ◽  
Author(s):  
D. G. Crowe ◽  
M. D. B. Burt ◽  
J. S. Scott
Keyword(s):  
Electron Microscopy ◽  
Echinococcus Granulosus ◽  
Basal Lamina ◽  
Light And Electron Microscopy ◽  
The Other ◽  
Great Similarity ◽  
Asexual Multiplication ◽  
Secretory Products ◽  
Unusual Type

Mature polycercus larvae of Paricterotaenia paradoxa were examined by light and electron microscopy. Although the larvae are of the cysticercoid type, they showed great similarity to the hydatid larvae of Echinococcus granulosus with respect to asexual multiplication and the presence of a PAS-positive layer of tissue that surrounds the larva. The microtriches were found to be of three different forms depending on their location. Two types of secretory products are described, one apparently associated with hook formation and the other apparently neurosecretory, associated with the extensive musculature. The suckers were found to be discrete organs covered by the scolex tegument and enclosed by a membrane contiguous with the basal lamina. The present findings of this unusual type of cestode larva are compared to the more normal cysticercoid and cysticercus larvae described by other workers.

Asci of the Pezizales. VI. The apical apparatus of Morchella esculenta, Helvella crispa, and Rhizina undulata. General discussion

1978 ◽  
Vol 56 (24) ◽  
pp. 3069-3082 ◽  
Author(s):  
Don A. Samuelson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light And Electron Microscopy ◽  
The Other ◽  
Present Series ◽  
Lipid Bodies ◽  
Taxonomic Significance ◽  
Taxonomic Relatedness ◽  
Morchella Esculenta ◽  
Bitunicate Ascus

Morphological, developmental, and cytochemical examinations were made with light and electron microscopy on the apical apparatuses of Morchella esculenta, Helvella crispa, and Rhizina undulata, all species with large, stipitate apothecia. Ascus tips in R. undulata were markedly thinner walled than the rest of the ascus, while those in M. esculenta and H. crispa were slightly thinner than the rest of the ascus wall. Lipid bodies were detected in developing asci of H. crispa and M. esculenta. Their unique occurrence in asci of members of the Morchellaceae and Helvellaceae may have taxonomic significance. With the electron microscope, opercula were distinguished cytochemically in all three species. In H. crispa and M. esculenta dehiscent zones were found to be restricted in the inner layer of the ascal wall. Characters of the apical apparatuses of H. crispa and M. esculenta suggest greater taxonomic relatedness between these species than with any other operculate group. The apical apparatus of R. undulata differed notably from the other species.The present series of studies has demonstrated distinct variability of the operculate ascus and its apical apparatus in morphology, cytochemistry, and development. Several major forms of the apical structures were observed. These examinations support the chemotaxonomic and cytological investigations on representatives of the Pezizales made previously by Arpin and Berthet. Outside of the Thelebolaceae, members of the Pezizales are chiefly characterized by the operculate dehiscence of their asci. Members of the Thelebolaceae eject their spores through a variety of dehiscent mechanisms. Present examinations of those representatives of the Thelebolaceae with functionally operculate apparatuses, i.e., Lasiobolus and Coprotus, support their transferrance to the Pyronemaceae. Taxa which form nonoperative opercula, i.e.,Ascozonus and Trichobolus, also show closer affinities with the Pyronemaceae than with the nonoperculate representatives of the Thelebolaceae. The nonoperculate members of the Thelebolaceae apparently do not belong in the operculate Discomycetes. The operculate ascus wall is structurally compared with the pored and bitunicate ascus walls. The terms 'bitunicate' and 'unitunicate' are redefined.

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