Electron microscopy of urediospore formation in Puccinia coronata avenae and P. graminis avenae

1976 ◽  
Vol 54 (9) ◽  
pp. 1010-1019 ◽  
Author(s):  
D. E. Harder
Keyword(s):  
Electron Microscopy ◽  
Lipid Droplets ◽  
Nuclear Division ◽  
Spore Wall ◽  
Puccinia Coronata ◽  
Sporogenous Cell ◽  
Cytoplasmic Inclusions ◽  
Puccinia Coronata Avenae ◽  
Variable Morphology ◽  
Spore Cell

Electron microscopy revealed that the sporogenous cells in urediosori of Puccinia coronata avenae and P. graminis avenae were enlarged at one end, and the cytoplasm was dense, vacuolated, and showed an early accumulation of lipid droplets. Urediospore formation was initiated by the outgrowth of a spore bud from the enlarged end of a sporogenous cell. A nuclear division occurred in the spore bud, the spore bud then grew to form the urediospore initial, and a septum formed to delineate the urediospore initial from the sporogenous cell. A further nuclear division occurred in the urediospore initial followed by septation to form the pedicel and spore cell. The urediospores rapidly grew to full size and further differentiation was marked by increased density of the cytoplasm, disappearance of vacuoles, increased lipid droplet accumulation, thickening of the spore wall, and spine formation. Nucleoli were not found in nuclei of mature urediospores. Possible paraphysis cells were intermixed with urediospores near the margins of urediosori of P. coronata. These cells were characterized by small nuclei which contained densely staining patches, a fine membranous network throughout the cytoplasm, and numerous cytoplasmic inclusions of variable morphology.

Ascus and ascospore development in Eleutherascus peruvianus. 2. Nuclear cytology and early ascus ontogeny

1983 ◽  
Vol 61 (6) ◽  
pp. 1599-1617 ◽  
Author(s):  
W. L. Steffens ◽  
J. P. Jones
Keyword(s):  
Electron Microscopy ◽  
Nuclear Division ◽  
Spore Wall ◽  
Giemsa Staining ◽  
Double Membrane ◽  
Vesicle Membranes ◽  
Ascospore Development ◽  
High Degree ◽  
Nuclear Cytology ◽  
Internal Order

A study was undertaken of the cytological events leading to ascus initiation through delimitation of the ascospores prior to spore wall deposition in Eleutherascus peruvianus Huang. As revealed by Giemsa staining, nuclei in asci which are derived from croziers in the classical manner undergo the three divisions, with each division occurring in a different plane. The result is a globose ascus with eight nuclei displaying a high degree of internal order with respect to the arrangement of the ascospores. Electron microscopy reveals that subsequent to the final nuclear division, the ascus becomes filled with several elongate segments of double membrane underlying the ascus plasmalemma. These membrane segments appear to result from marked focal invaginations of the ascus plasmalemma and ultimately fuse together to form the ascus vesicle. Occasional observations of nuclei outside of the ascus vesicle membranes are believed to account for the often observed phenomenon of asci with odd numbers of ascospores. The significance of these findings relative to those for some close allies is discussed.

Electron Microscopy of Fibroblasts from Myotonic Muscular Dystrophy Patients

1981 ◽  
Vol 39 ◽  
pp. 498-499
Author(s):  
S. E. Miller ◽  
G. B. Hartwig ◽  
R. A. Nielsen ◽  
A. P. Frost ◽  
A. D. Roses
Keyword(s):  
Electron Microscopy ◽  
Muscular Dystrophy ◽  
Genetic Diseases ◽  
Skin Fibroblasts ◽  
Inborn Errors ◽  
Cytoplasmic Inclusions ◽  
Cultured Skin ◽  
Myotonic Muscular Dystrophy ◽  
Glycosaminoglycan Metabolism

Many genetic diseases can be demonstrated in skin cells cultured in vitro from patients with inborn errors of metabolism. Since myotonic muscular dystrophy (MMD) affects many organs other than muscle, it seems likely that this defect also might be expressed in fibroblasts. Detection of an alteration in cultured skin fibroblasts from patients would provide a valuable tool in the study of the disease as it would present a readily accessible and controllable system for examination. Furthermore, fibroblast expression would allow diagnosis of fetal and presumptomatic cases. An unusual staining pattern of MMD cultured skin fibroblasts as seen by light microscopy, namely, an increase in alcianophilia and metachromasia, has been reported; both these techniques suggest an altered glycosaminoglycan metabolism An altered growth pattern has also been described. One reference on cultured skin fibroblasts from a different dystrophy (Duchenne Muscular Dystrophy) reports increased cytoplasmic inclusions seen by electron microscopy. Also, ultrastructural alterations have been reported in muscle and thalamus biopsies from MMD patients, but no electron microscopical data is available on MMD cultured skin fibroblasts.

scholarly journals Parasitism of spores of the vesicular-arbuscular mycorrhizal fungus, Glomus dimorphicum

2005 ◽  
Vol 72 (1) ◽  
pp. 27-32 ◽  
Author(s):  
S.M. Boyetchko ◽  
J.P. Tewari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Host Response ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Spore Wall ◽  
Vesicular Arbuscular ◽  
Scanning Electron

Spores of Glomus dimorphicum were examined for parasitism. Light and scanning electron microscopy revealed perforations, approximately 0.25 to 1.0 µm in diameter, in the spore wall. The presence of papillae, a dynamic host response, suggested that the parasitism occurred while the vesicular-arbuscular mycorrhizal fungus was still alive. No filamentous structures were detected in the spores; however, cysts of amoeba-like organisms were found in the spores and were also observed on agar plates on which surface-sterilized spores of G. dimorphicum containing such organisms were placed. It is postulated that an amoeba-like organism was the parasite, since the perforations on the spore wall were minute and no bacteria or fungi were seen inside the spores.

scholarly journals The materno-fetal interface in llama (Lama guanicoe glama)

2007 ◽  
Vol 27 (6) ◽  
pp. 221-228 ◽  
Author(s):  
David M. Iturrizaga ◽  
Flavia T. Verechia ◽  
Tatiana C. Santos ◽  
Pedro P. Bombonato ◽  
Dulcinéa G. Teixeira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acid Phosphatase ◽  
Natural Habitat ◽  
Lama Guanicoe ◽  
Trophoblastic Cells ◽  
Variable Morphology ◽  
Epidermal Membrane ◽  
High Level ◽  
Uterine Glands ◽  
Scanning Electron

Samples from 9 llamas (28 through 36 weeks of gestation) were collected and fixed in 4% buffered paraformaldehyde (light microscopy) and in 2.5% buffered glutaraldehyde (transmission and scanning electron microscopy). The material was processed in paraplast and slides (5mm) were stained with HE, PAS, Masson-Trichrome, acid phosphatase and Perl's. The uteroferrin was immunolocalized. The results show that llama placenta is chorioallantoic, diffuse, folded and epitheliochorial, and the fetus is covered with an epidermal membrane. The trophoblast cells have variable morphology: cubic, rounded and triangular cells, with cytoplasm containing PAS-positive granules. Binucleated cells with large cytoplasm and rounded nuclei, as well as giant trophoblastic cells with multiple nuclei were also observed. Numerous blood vessels were observed beneath the cells of the uterine epithelium and around the chorionic subdivided branches. Glandular activity was shown by PAS, Perl's, and acid phosphatase positive reactions in the cytoplasm and glandular lumen, and by immunolocalization of the uteroferrin in the glandular epithelium. The uterine glands open in spaces formed by the areoles, which are filled by PAS-positive material. The llama fetus was covered by the epidermal membrane, composed of stratified epithelium, with up to seven layers of mono-, bi- or trinucleated cells. The high level of maternal and fetal vascularization surfaces indicates an intense exchange of substances across both surfaces. The metabolic activity shown in the uterine glands suggests an adaptation of the gestation to the high altitudes of the natural habitat of this species.

scholarly journals A conserved family of proteins facilitates nascent lipid droplet budding from the ER

2015 ◽  
Vol 211 (2) ◽  
pp. 261-271 ◽  
Author(s):  
Vineet Choudhary ◽  
Namrata Ojha ◽  
Andy Golden ◽  
William A. Prinz
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Lipid Metabolism ◽  
Caenorhabditis Elegans ◽  
Lipid Droplet ◽  
Lipid Droplets ◽  
De Novo ◽  
Fat Storage ◽  
Higher Eukaryotes ◽  
Er Membrane

Lipid droplets (LDs) are found in all cells and play critical roles in lipid metabolism. De novo LD biogenesis occurs in the endoplasmic reticulum (ER) but is not well understood. We imaged early stages of LD biogenesis using electron microscopy and found that nascent LDs form lens-like structures that are in the ER membrane, raising the question of how these nascent LDs bud from the ER as they grow. We found that a conserved family of proteins, fat storage-inducing transmembrane (FIT) proteins, is required for proper budding of LDs from the ER. Elimination or reduction of FIT proteins in yeast and higher eukaryotes causes LDs to remain in the ER membrane. Deletion of the single FIT protein in Caenorhabditis elegans is lethal, suggesting that LD budding is an essential process in this organism. Our findings indicated that FIT proteins are necessary to promote budding of nascent LDs from the ER.

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