Ultrastructural changes during germination of Geotrichum candidum arthrospores

1973 ◽  
Vol 19 (8) ◽  
pp. 1031-1034 ◽  
Author(s):  
S. D. Steele ◽  
T. W. Fraser
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Germ Tube ◽  
Tube Wall ◽  
Geotrichum Candidum ◽  
Spore Wall ◽  
Ultrastructural Changes ◽  
Wall Material ◽  
Apparent Increase ◽  
Tube Emergence

The dormant arthrospore in Geotrichum candidum has three, possibly four, layers making up the spore wall. Nuclei, mitochondria, free ribosomes, fragments of endoplasmic reticulum, various small vacuoles, and particles of glycogen were observed within the protoplasm. During germination a new layer of wall material forms between the original spore wall and the cytoplasm. This new layer is confined to the region where germ-tube emergence occurs and is continuous with the germ-tube wall. After germ-tube emergence vesicles were seen at the apices of germlings. Another feature of germination was an apparent increase in the amount of endoplasmic reticulum, some of which appears to assume the function of the Golgi apparatus.

Ultrastructure and development of urediospore ornamentation in Melampsora lini

1971 ◽  
Vol 49 (12) ◽  
pp. 2067-2073 ◽  
Author(s):  
L. J. Littlefield ◽  
C. E. Bracker
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Outer Surface ◽  
Spore Wall ◽  
Wall Material ◽  
Wild Type ◽  
Melampsora Lini ◽  
Inner Surface ◽  
External Position ◽  
Basal Portion

The urediospores of Melampsora lini (Ehrenb.) Lev. are echinulate, with spines ca. 1 μ long over their surface. The spines are electron-transparent, conical projections, with their basal portion embedded in the electron-dense spore wall. The entire spore, including the spines, is covered by a wrinkled pellicle ca. 150–200 Å thick. The spore wall consists of three recognizable layers in addition to the pellicle. Spines form initially as small deposits at the inner surface of the spore wall adjacent to the plasma membrane. Endoplasmic reticulum occurs close to the plasma membrane in localized areas near the base of spines. During development, the spore wall thickens, and the spines increase in size. Centripetal growth of the wall encases the spines in the wall material. The spines progressively assume a more external position in the spore wall and finally reside at the outer surface of the wall. A mutant strain with finely verrucose spores was compared to the wild type. The warts on the surface of the mutant spores are rounded, electron-dense structures ca. 0.2–0.4 μ high, in contrast to spines of the wild type. Their initiation near the inner surface of the spore wall and their eventual placement on the outer surface of the spore are similar to that of spines. The wall is thinner in mutant spores than in wild-type spores.

Fine structure of sporangiole development in Choanephora cucurbitarum (Mucorales)

1982 ◽  
Vol 60 (11) ◽  
pp. 2313-2324 ◽  
Author(s):  
Michael T. Higham ◽  
Kathleen M. Cole
Keyword(s):  
Electron Microscopy ◽  
Germ Tube ◽  
Tube Wall ◽  
Outer Wall ◽  
Spore Wall ◽  
Wall Layer ◽  
Choanephora Cucurbitarum ◽  
Dark Staining ◽  
Granular Vesicles ◽  
Scanning Electron

Spore development was studied in Choanephora cucurbitarum by using transmission and scanning electron microscopy. Sporangioles are produced by expansion of the ampulla wall. A two-layered spore wall is then constructed within the spine-covered sporangiole wall. The outer spore wall layer is longitudinally grooved and is devoid of spines or appendages. The inner wall layer is thinner and electron transparent. During wall production, dark-staining granular vesicles were observed in the spore cytoplasm. Their contents stained similarly to the material of the outer wall layer. Mature spores possessed a third, innermost wall layer. This was identified as a new wall layer, which was continuous with the germ-tube wall of germinated spores. Released spores were observed to be contained within the sporangiole during dispersal and germination.

scholarly journals The amounts and rates of export of polysaccharides found within the membrane system of maize root cells

1974 ◽  
Vol 142 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Dianna J. Bowles ◽  
D. H. Northcote
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Golgi Apparatus ◽  
Cell Surface ◽  
Rough Endoplasmic Reticulum ◽  
Membrane System ◽  
Maize Root ◽  
Wall Material ◽  
Cell Wall Material ◽  
Root Cells

1. Maize seedling roots were incubated in vivo with d-[U-14C]glucose for 2, 5, 10, 15, 30 and 45min. The total incorporation of radioactivity into polysaccharide components in isolated fractions was investigated, and the pattern of incorporation into different polysaccharide components within the rough endoplasmic reticulum, Golgi apparatus and exported material was analysed. 2. The membrane compartments reached a saturation value of radioactivity in polysaccharide components by 30min incubation. Radioactivity in exported polysaccharide continued to increase after that time. The latter was formed and maintained by a steady-state turnover of polysaccharide synthesis and transport from the membrane system. 3. If the only access of the slime polysaccharide to the cell surface is via dictyosome-derived vesicles, the amount of slime components in the Golgi apparatus would have to be displaced every 0.3min in order to maintain the observed rates of increase in slime. This is in contrast with a displacement time of about 2.5min that is necessary for polysaccharide components in the Golgi apparatus to produce the observed increase in cell-wall material. The activity of the membrane system in the production of maize root slime is 8 times as great as that of the membrane system involved in cell-wall synthesis. 4. If the amount of polysaccharide material in the Golgi apparatus is maintained only by inflow of polymeric material from the rough endoplasmic reticulum the total amount of slime components in the rough endoplasmic reticulum would have to be displaced every 7min to maintain a constant amount in the Golgi apparatus. If the endoplasmic reticulum contributed directly to the cell surface in the synthesis of cell-wall material, displacement times necessary to maintain the observed rate of polymer production would be very slow.

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.

Fine structure of the spores of Minchinia chitonis (Lankester, 1885) Labbé, 1896 (Sporozoa: Haplosporida), a parasite of the chiton, Lepidochitona cinereus

Parasitology ◽  
1980 ◽  
Vol 81 (1) ◽  
pp. 169-176 ◽  
Author(s):  
S. J. Ball
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Morphological Study ◽  
Smooth Endoplasmic Reticulum ◽  
Spore Wall ◽  
Single Nucleus

SUMMARYA morphological study of the fine structure of the spores of Minchinia chitonis, a haplosporidian parasite of the chiton, Lepidochitona cinereus, is described. The spores contained a single nucleus, mitochondria, haplosporosomes, smooth endoplasmic reticulum, ribosomes and a large spherule (presumed Golgi apparatus). The spore wall was discontinuous at the spherule end, forming an opening covered by a lid which rested on a circumscribed flange. The flange of the spore wall and the lid were continuous in only one area which served as a hinge. The entire spore was encapsulated by epispore cytoplasm bounded by a strengthened membrane and extended to form 2 long projections, one at either end.

Ultrastructure and lipid identification during conidium germination of Stemphylium sarcinaeforme

1976 ◽  
Vol 22 (1) ◽  
pp. 92-100 ◽  
Author(s):  
Gordon M. Murray ◽  
Douglas P. Maxwell
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Total Lipid ◽  
Germ Tube ◽  
Tube Wall ◽  
Dry Weight ◽  
Lipid Bodies ◽  
Conidium Germination ◽  
Germ Tubes ◽  
Qualitative Changes

Multicelled conidia of Stemphylium sarcinaeforme germinate in water forming several germ tubes. Individual cells within conidia are connected by pores which are plugged in ungerminated conidia and open in germinated ones. During germination, vacuoles enlarge, endoplasmic reticulum profiles increase in number, and mitochondria change from spherical to elongate. The germ tube wall is laid down at the site of emergence from the conidium. Shortly after germination, a septum with a central pore forms where the germ tube emerged. The germ tube wall is surrounded by a fibrillar sheath. Lipid bodies are closely associated with vacuoles during germination. The ultrastructural location of lipid was found by extraction of conidia with lipid solvents. Total lipid decreases from 14.4% of the dry weight of ungerminated conidia to 13.4% of the dry weight of conidia germinated for 10 h. No qualitative changes occurred in the major lipid classes of conidia during germination. The activities of lipase and acid phosphatase were detected in ungerminated and germinated conidia.

Surface structure of germinating Uromyces dianthi urediospores as observed by scanning electron microscope

1971 ◽  
Vol 49 (12) ◽  
pp. 2243-2244 ◽  
Author(s):  
D. R. Jones
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Structure ◽  
Germ Tube ◽  
Spore Wall ◽  
Spore Surface ◽  
Germ Pore ◽  
Tube Emergence ◽  
Scanning Electron

Germ pore regions could not be located on the surface of Uromyces dianthi urediospores before germination. Germ tube emergence did not split the spore wall. Double spine features were observed on the spore surface.

The ultrastructure of Geotrichum candidum hyphae

1973 ◽  
Vol 19 (12) ◽  
pp. 1507-1512 ◽  
Author(s):  
S. D. Steele ◽  
T. W. Fraser
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Apical Cell ◽  
Cell Types ◽  
Geotrichum Candidum ◽  
Wall Material ◽  
Surrounding Cell ◽  
Golgi Bodies ◽  
Apical Cells ◽  
Intranuclear Microtubules

Complete septa divide the hyphae of Geotrichum candidum into many compartments or cells. Two cell types are readily recognizable, (i) the apical cell, delimited by one septum and the surrounding cell wall, and (ii) the sub- or non-apical cell, delimited by two septa and the surrounding cell wall. Vacuolation of the apical cells is slight compared with that of subapical cells. Apical cells contain many vesicles, some of which are elongated and branched, possibly forming an interconnecting tubular network; other vesicles were observed distributed about the apical zone or aggregated to form an apical body (the Spitzenkörper). Vesicles are also evident in subapical cells, but only in association with developing septa. Golgi bodies were not observed in any cells, their function in vesicle production possibly being taken by a modification of part of the endoplasmic reticulum. Both cell types contained mitochondria with contrasting electron-staining properties. Some stages of mitosis were observed. The nucleus appears to retain its envelope throughout division and exhibits intranuclear microtubules attached to spindle plaques. Septa were formed by a centripetal deposition of wall material, plasmodesmata developing during this process. Another deposition of wall material occurs after the centripetal deposition thus allowing a secondary thickening of the septum to take place.

Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells

1971 ◽  
Vol 29 ◽  
pp. 572-573
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Liver Biopsy ◽  
Alcoholic Hepatitis ◽  
Ultrastructural Changes ◽  
Main Mass ◽  
Biliary Epithelial Cells ◽  
Biopsy Specimens ◽  
Alcoholic Hyalin

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.

Golgi Apparatus and Melanogenesis: Ultrastructural Study of a Human Cellular Blue Nevus (Melanocytoma)

1973 ◽  
Vol 31 ◽  
pp. 380-381
Author(s):  
S.R. Allegra
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Ultrastructural Study ◽  
The Other ◽  
Blue Nevus ◽  
Normal Complement ◽  
Golgi Vesicles ◽  
Golgi System ◽  
The Subject ◽  
Cellular Blue Nevus

The respective roles of the ribo somes, endoplasmic reticulum, Golgi apparatus and perhaps nucleus in the synthesis and maturation of melanosomes is still the subject of some controversy. While the early melanosomes (premelanosomes) have been frequently demonstrated to originate as Golgi vesicles, it is undeniable that these structures can be formed in cells in which Golgi system is not found. This report was prompted by the findings in an essentially amelanotic human cellular blue nevus (melanocytoma) of two distinct lines of melanocytes one of which was devoid of any trace of Golgi apparatus while the other had normal complement of this organelle.

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