Ultrastructural studies of ascospore liberation in Pyronema domesticum

1977 ◽  
Vol 55 (19) ◽  
pp. 2544-2549 ◽  
Author(s):  
Ching-Yuan Hung
Keyword(s):  
Single Unit ◽  
Spore Wall ◽  
Main Body ◽  
Large Vacuole ◽  
Ultrastructural Studies ◽  
Apical Pore ◽  
Total Disappearance

Ascospores of Pyronema domesticum contain three distinct spore wall layers. The liberation of ascospores presumably commences immediately after the three spore wall layers are formed. This is evidenced by the fact that vesiculation of the investing membrane was observed at the time when three wall layers could be distinguished. Vesiculation continues until the total disappearance of the perispore. Concurrently the epiplasm of the ascus degenerates and converts into a large vacuole within the ascus. Spores are violently ejected through the apical pore that is surrounded by a weakened apical ring. Presumably eight ascospores are discharged at the same time but do not adhere as a single unit. The operculum is generally not hinged to the main body of the ascus and an ascus without ascospores degenerates.

Ultrastructural Studies of the Spore Wall of Gigaspora albida (Glomales)

Mycologia ◽  
1993 ◽  
Vol 85 (6) ◽  
pp. 883 ◽  
Author(s):  
Leonor C. Maia ◽  
James W. Kimbrough ◽  
Gerald Benny
Keyword(s):  
Spore Wall ◽  
Ultrastructural Studies ◽  
Gigaspora Albida

Fine structure of aesthetasc chemoreceptors in the crayfish Orconectes propinquus

1986 ◽  
Vol 64 (2) ◽  
pp. 392-399 ◽  
Author(s):  
Ann Jane Tierney ◽  
C. S. Thompson ◽  
D. W. Dunham
Keyword(s):  
Distal Portion ◽  
Main Body ◽  
Decapod Crustaceans ◽  
Orconectes Propinquus ◽  
Outer Sheath ◽  
Apical Pore ◽  
Cell Layers ◽  
Chemical Stimuli ◽  
Sensory Endings ◽  
Sheath Cells

The outer antennular flagella of decapod crustaceans bear chemoreceptive hairs called aesthetascs. In the crayfish Orconectes propinquus these sensilla are located ventrally on the 11–13 most distal segments of the outer flagella. Two clumps of 3–6 aesthetascs occur on each segment, giving a total of approximately 80 aesthetascs per outer flagellum. Aesthetascs are100–150 μm long and about 12 μm in diameter. Each has a single annulation 30 μm from the hair base. The sensilla arise from immovable sockets and are directed distally at a 45° angle to the main body of the antennule. Aesthetascs lack an apical pore. However, the distal portion of each sensillum has thin cuticular walls which are readily penetrated by dye; this is probably the site where chemical stimuli enter. In O. propinquus each aesthetasc is innervated by 40–110 sensory neurons. Each neuron gives rise to a dendrite that branches into two cilia (9 × 2 + 2 structure; 0.15–0.20 μm in diameter). No further branching of outer dendritic segments occurs and thus each aesthetasc contains 80–220 sensory endings. Within the antennule lumen the dendrites are surrounded by two sheath cell layers, an inner layer and an outer layer. The inner sheath cells ascend 50 μm into the aesthetasc lumen; the outer sheath cells terminate at the sensilla bases. The outer dendritic segments gradually taper in diameter and terminate 25 μm from the sensilla tips.

Spore ontogeny of Galiella rufa (Pezizales)

1996 ◽  
Vol 74 (10) ◽  
pp. 1651-1656 ◽  
Author(s):  
Li-Tzu Li ◽  
James W. Kimbrough
Keyword(s):  
Secondary Wall ◽  
Spore Wall ◽  
The Other ◽  
Ultrastructural Studies

Galiella is one of the genera of the dark-colored apothecial Sarcosomataceae, tribe Galielleae, with cyanophilous spore markings. Ultrastructural studies show that spore wall development of Galiella rufa is similar to the subgenus Discina of Gyromitra in Helvellaceae and to the other Sarcosomataceae, especially Plectania nannfeldtii, which both have fine secondary wall spore ornaments. The multinucleate ascospores found in G. rufa may show relationship to the Morchellaceae and the Helvellaceae. Keywords: ascospore ontogeny, Galiella, Sarcosomataceae, ultrastructure.

Ultrastructural studies on the sporozoite of Eimeria tenella

Parasitology ◽  
1969 ◽  
Vol 59 (1) ◽  
pp. 67-72 ◽  
Author(s):  
John F. Ryley
Keyword(s):  
Electron Microscope ◽  
Lipid Droplets ◽  
Eimeria Tenella ◽  
Regular Array ◽  
Whole Cells ◽  
Ultrastructural Studies ◽  
Fixed Material ◽  
Apical Pore ◽  
Technical Collaboration

The structure of the sporozoite of Eimeria tenella has been studied with the aid of the electron microscope, using both sectioned fixed material and negatively stained or shadowed whole cells. An apical ring gives rise to a series of 24 fibrils which extend posteriorly under a double bilamellar membrane. Within the apical ring lies a conoid with spirally arranged tubules and an apical pore; under some conditions at least this conoid can be pushed forward beyond the apical ring. Originating within the conoid are a group of club-shaped organelles which extend backwards into the cell to lie among an extensive regular array of micronemes. The nucleus lies between two apparently structureless paranuclear bodies, and scattered throughout the remaining cytoplasm are mitochondria with tubular cristae, oval structures containing amylopectin, occasional lipid droplets, and vesicles containing nondescript material possibly undergoing digestion and which may have a possible connexion with a lateral micropyle.I am indebted to Mrs Muriel Bentley for much technical collaboration and to Mrs McLaren for making her manuscript available before publication.

Spore ontogeny in species of Phillipsia and Wynnea (Pezizales)

1996 ◽  
Vol 74 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Li-Tzu Li ◽  
James W. Kimbrough
Keyword(s):  
Secondary Wall ◽  
Spore Wall ◽  
Primary Wall ◽  
Ultrastructural Studies ◽  
Wall Components

Some species of the genera Phillipsia and Wynnea have similar longitudinally ridged cyanophobic ascospore markings. Ultrastructural studies show that the cyanophobic spore markings are part of the primary wall. In contrast, the cyanophilous spore ornaments are formed by the secondary wall. The observation of spore wall development indicates that the sources of the spore wall components are the sporoplasm and the epiplasm. Based on the pinkish hymenial color of fresh young apothecia and the cyanophobic spore ridges found only in some members of the Sarcoscyphaceae, Wynnea belongs to the Sarcoscyphaceae. Keywords: Pezizales, Phillipsia, Sarcoscyphaceae, spore wall ontogeny, ultrastructure, Wynnea.

Ultrastructural studies on germinating ascospores of Daldinia concentrica

1976 ◽  
Vol 54 (8) ◽  
pp. 698-705 ◽  
Author(s):  
A. Beckett
Keyword(s):  
Electron Microscope ◽  
Germ Tube ◽  
Tube Wall ◽  
Spore Wall ◽  
Wall Layer ◽  
Ultrastructural Studies ◽  
Early Stages ◽  
Ascospore Germination ◽  
Daldinia Concentrica

Ascospore germination in Daldinia concentrica has been studied using light and electron microscope techniques. Preliminary observations indicated that lipid globules were utilized during early stages of germination. Apical wall vesicles were localized during germ tube initiation and were involved in the differentiation of a filamentous germ tube. Wall synthesis occurred during germination and resulted in a new wall layer, which was different in ultratexture to the spore wall and which formed the germ tube wall. Possible implications of the concept of spore wall and vegetative wall types during germination are discussed.

Chemotaxonomic and ultrastructural studies on three species of Tilletia occurring on wheat

1968 ◽  
Vol 14 (10) ◽  
pp. 1149-1154 ◽  
Author(s):  
J. L. Laseter ◽  
W. M. Hess ◽  
J. D. Weete ◽  
D. L. Stocks ◽  
D. J. Weber
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
External Surface ◽  
Saturated Fatty Acids ◽  
Spore Wall ◽  
Electron Microscopic ◽  
Ultrastructural Studies ◽  
Hydrocarbon Content ◽  
Spore Walls ◽  
Reverse Situation

Electron microscopic investigations and chemical analyses were made on the spores of three species of Tilletia. Frozen-etched preparations examined in the electron microscope revealed that the spore walls of both T. foetida (smooth external surface) and T. caries (reticulate surface with some hair-like projections) contain two layers. The spore wall of T. controversa (complex reticulate surface with many hair-like projections) contains three layers. The outer layer in T. controversa has granular regions which form a reticulated pattern on the surface. The hydrocarbon content of the three Tilletia species was essentially the same. The compounds in benzene and the methanol (free fatty acids) fractions gave distinct gas chromatographic patterns for each of the three species. T. foetida was the highest in saturated fatty acids with T. controversa second followed by T. caries. The reverse situation existed with respect to the unsaturated fatty acids.

Ultrastructural studies of primary spores of Conidiobolus, Erynia, and related Entomophthorales

1989 ◽  
Vol 67 (9) ◽  
pp. 2576-2589 ◽  
Author(s):  
J. P. Latgé ◽  
D. F. Perry ◽  
M. C. Prévost ◽  
R. A. Samson
Keyword(s):  
Outer Layer ◽  
Germ Tube ◽  
Spore Wall ◽  
Wall Layer ◽  
Spore Formation ◽  
Dense Layer ◽  
Nuclear Ultrastructure ◽  
Ultrastructural Studies ◽  
Thin Electron ◽  
Definition Of

Wall development during primary spore formation, discharge, and germination of Entomophthorales is emphasized in ultrastructural studies of Conidiobolus, Entomophaga, Neozygites, and Erynia. In the fungi examined, spore and sporophore walls consist of a thick, electron-translucent inner layer and a thin, electron-dense outer layer. During spore formation, cytoplasm of the supporting sporophore cell migrates into the spore initial. As the former cell empties, a septum develops. Discharge is caused by inversion of the papillum, which lacks the electron-dense layer. Only in Erynia did the two spore wall layers separate upon impact. Intracytoplasmic organization of the primary spore is typical of the Zygomycotina; the morphology of organelles was characteristic of species, whereas nuclear ultrastructure was consistent within genera. Conidiobolus nuclei have a prominent nucleolus that lacks heterochromatin, in contrast with the other genera where large patches of heterochromatin were observed. Upon germination, no rupture of the spore outer layer was observed other than at points of germ tube emergence. The germ tube wall was continuous with the inner spore wall layer. The results are discussed in reference to Entomophthorales taxonomy and definition of the terms conidium and monosporous sporangiolum.

Ultrastructural Studies of the Spore Wall of Gigaspora Albida (Glomales)

Mycologia ◽  
1993 ◽  
Vol 85 (6) ◽  
pp. 883-889 ◽  
Author(s):  
Leonor C. Maia ◽  
James W. Kimbrough ◽  
Gerald Benny
Keyword(s):  
Spore Wall ◽  
Ultrastructural Studies ◽  
Gigaspora Albida

A taxonomic reappraisal of the genus Ceriosporopsis based on ultrastructure

1994 ◽  
Vol 72 (10) ◽  
pp. 1550-1559 ◽  
Author(s):  
M. Yusoff ◽  
E. B. G. Jones ◽  
S. T. Moss
Keyword(s):  
Key Words ◽  
New Genus ◽  
Marine Fungi ◽  
Spore Wall ◽  
Ultrastructural Studies ◽  
The Difference

This paper reports results of ultrastructural studies of ascospores and their appendages in Ceriosporopsis caduca, Ceriosporopsis circumvestita, and Ceriosporopsis capillacea. Ceriosporopsis caduca and C. capillacea have polar appendages that arise as outgrowths of the spore wall. The exosporium, which initially extends over the polar appendages, later forms a collar at their base. In C. circumvestita, the sheath is mesosporial in origin and is chambered; an exosporium is absent, and there is no collar at the base of the appendage. Because of the difference in ascospore appendage structure, C. circumvestita is transferred to a new genus Lautisporopsis. The taxonomy of the remaining species of Ceriosporopsis is reviewed, and comparisons are made with Bovicornua intricata. Key words: Ascomycotina, marine fungi, taxonomy, ultrastructure, Lautisporopsis.

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