Intracellular location of enzymes in Rhodopseudomonas spheroides

1968 ◽  
Vol 170 (1020) ◽  
pp. 319-329 ◽  
Keyword(s):  
Cell Wall ◽  
Cytoplasmic Membrane ◽  
Succinic Dehydrogenase ◽  
Particulate Material ◽  
Zinc Protoporphyrin ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Intracellular Location ◽  
Microscopic Studies ◽  
Rhodopseudomonas Spheroides

By differential centrifugation of extracts of pigmented Rhodopseudomonas spheroides a number of constituents, phospholipid and lipid ornithine, and enzymes, zinc protoporphyrin chelatase, succinic dehydrogenase and S-adenosylmethionine-magnesium protoporphyrin methyltransferase, have been found to be associated both with chromatophores and with non-pigmented particulate material. These components are present in both types of material at about the same level. In extracts of non-pigmented organisms the particulate material contains some of the above components, but others are only present in low amounts. The subcellular structures present in the particulate material—ribosomes, cell wall and cytoplasmic membrane—have only been partially separated but, by comparing the distribution of the components listed above with those of known components of ribosomes and cell wall, it is probable that they are associated with cytoplasmic membrane. These studies suggest that the cytoplasmic membrane, apart from lacking the photosynthetic pigments, has a composition similar to that of chromatophores. The data are consistent with the conclusion drawn from electron microscopic studies that chromatophores are derived by invagination of the cytoplasmic membrane.

Peroxidase Localization in Hartmanella Trophozoites

1971 ◽  
Vol 29 ◽  
pp. 346-347 ◽  
Author(s):  
George E. Childs ◽  
Joseph H. Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Ultrastructural Localization ◽  
Pathogenic Strain ◽  
Oxidative Enzymes ◽  
Differential Centrifugation ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
The Subject ◽  
Axenic Cultures

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.

A comparison of the effects of several antifungal imidazole derivatives and polyenes on Candida albicans: an ultrastructural study by scanning electron microscopy

1982 ◽  
Vol 28 (10) ◽  
pp. 1119-1126 ◽  
Author(s):  
M. Bastide ◽  
S. Jouvert ◽  
J.-M. Bastide
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Candida Albicans ◽  
Cytoplasmic Membrane ◽  
Electron Microscopic Examination ◽  
Yeast Cells ◽  
Electron Microscopic ◽  
Imidazole Derivatives ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.

Electron microscopic studies on the formation of vesicular bodies during cell wall degradation and regeneration in yeast

1977 ◽  
Vol 17 (4) ◽  
pp. 293-297
Author(s):  
V. V. Dmitriev ◽  
A. B. Tsiomenko ◽  
E. N. Ratner ◽  
V. K. Akimenko ◽  
B. A. Fikhte
Keyword(s):  
Cell Wall ◽  
Cell Wall Degradation ◽  
Electron Microscopic ◽  
Microscopic Studies

Electron microscopic studies on the formation of vesicular bodies during cell wall degradation and regeneration in yeast

1977 ◽  
Vol 17 (4) ◽  
pp. 293-297 ◽  
Author(s):  
V. V. Dmitriev ◽  
A. B. Tsiomenko ◽  
E. N. Ratner ◽  
V. K. Akimenko ◽  
B. A. Fikhte
Keyword(s):  
Cell Wall ◽  
Cell Wall Degradation ◽  
Electron Microscopic ◽  
Microscopic Studies

scholarly journals ELECTRON MICROSCOPIC STUDIES ON STREPTOCOCCI

1969 ◽  
Vol 130 (5) ◽  
pp. 1063-1091 ◽  
Author(s):  
John Swanson ◽  
Konrad C. Hsu ◽  
Emil C. Gotschlich
Keyword(s):  
Cell Wall ◽  
Nitrous Acid ◽  
Intact Cell ◽  
M Protein ◽  
Acid Extraction ◽  
Electron Microscopic ◽  
Streptococcal Cell Wall ◽  
Before And After ◽  
Specific Polysaccharide ◽  
Microscopic Studies

The presence of M antigens on group A streptococci is associated with hairlike fimbriae that cover the surface of the streptococcal cell wall and are demonstrable by electron microscopy. These fimbriae also may be associated with R antigen. Like M protein, the surface fimbriae are destroyed by trypsin treatment and reappear when "trypsinized" streptococci are reincubated in fresh, trypsin-free broth. Ferritin-conjugated, type-specific antibodies localize on homologous M+ cells in a pattern suggestive of several M antigenic sites along the length of individual surface fimbria. The M-associated fimbriae remain on the residual cell wall after removal of the bulk of group-specific polysaccharide through nitrous acid extraction. This suggests attachment of the fimbriae to the mucopeptide and minor polysaccharide components remaining in the nitrous acid-extracted wall. The pattern of localization of ferritin-conjugated antibodies on homologous streptococci before and after trypsin exposure and upon reincubation of the trypsinized cells in fresh medium suggests the following hypothesis: M antigen is secreted by the cell, is partially excreted through the otherwise intact cell wall, and is bound by the wall so that M protein occupies a peripheral, exposed position on the surfaces of the streptococcal cell wall.

scholarly journals ELECTRON MICROSCOPIC STUDIES ON STREPTOCOCCI

1973 ◽  
Vol 138 (1) ◽  
pp. 245-258 ◽  
Author(s):  
John Swanson ◽  
Emil C. Gotschlich
Keyword(s):  
Cell Wall ◽  
Horseradish Peroxidase ◽  
Electron Microscopic ◽  
Streptococcal Cell Wall ◽  
Outermost Surface ◽  
Laminar Distribution ◽  
Specific Polysaccharide ◽  
Microscopic Studies ◽  
Group A ◽  
Protein Cell

The location of Group A carbohydrate in the streptococcal cell wall has been studied by several ultrastructural techniques. The findings, based largely on use of ferritin- and horseradish peroxidase-conjugated antibodies, are interpreted as demonstrating a discrete laminar distribution of the group-specific polysaccharide. This carbohydrate layer is located on the outermost surface of the cell wall in organisms lacking protein cell wall antigens.

Peripheral structures of plastids and ultrastructural localization of acid phosphatase and succinic dehydrogenase in a variegated Betula pubescens mutant

1975 ◽  
Vol 53 (10) ◽  
pp. 1072-1077 ◽  
Author(s):  
Niina Valanne
Keyword(s):  
Cell Wall ◽  
Acid Phosphatase ◽  
Succinic Dehydrogenase ◽  
Leaf Tissue ◽  
Ultrastructural Localization ◽  
Betula Pubescens ◽  
High Light ◽  
Electron Microscopic ◽  
White Leaf ◽  
Electron Microscopic Localization

In white leaf tissue from a variegated Betula pubescens mutant, acid-phosphatase activity is seen only in the vacuoles and the cell wall and no precipitation is evident inside the mutant plastids. The electron-microscopic localization of succinic dehydrogenase reveals activity in the intracristal spaces of mitochondria and the envelopes of both mitochondria and plastids. Since precipitation is not apparent inside the protrusions of the plastids and only the membrane occasionally shows a typical mitochondrial reaction, evidence seems to be lacking which indicates that mitochondria originate from plastids. The mitochondrion-like particles budding from the mutant plastids are considered to be proplastids. Peripheral vesicular structures are also seen in the chloroplasts of green leaf tissue from plants growing at high light intensities.

The fine structure of some strains of Humicola Traaen

1974 ◽  
Vol 20 (2) ◽  
pp. 237-239 ◽  
Author(s):  
M. de Bertoldi ◽  
F. Mariotti ◽  
C. Filippi
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Cell Surface ◽  
Outer Wall ◽  
Wall Layer ◽  
The Other ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Different Types ◽  
Microscopic Studies

The fine structure of three unclassified strains of Humicola and of H. grisea has been investigated. The hyphae of all the strains show septa with Woronin bodies of the ascomycetous type. The cytoplasm contains many nuclei per cell, mitochondria, ribosomes, and endoplasmic vesicles, all typical of fungal cells. Electron-microscopic studies of thin sections of mature aleuriospores reveal a thick multilayered cell wall and an accumulation, inside the spore, of β-hydroxybutyrate granules. Aleuriospores exhibit different types of cell surface; the outer wall layer of two strains is smooth, while the outer layer of the other strains is rough because of the presence of melanizing bodies on the cell wall matrix. The fine structure of phialospores and microconidia is also described. Differences in the fine structure among the strains studied are reported.

A Study of the Structure of the Cell Wall of Spirillum Serpens Using Frozen, Hydrated Specimens

1976 ◽  
Vol 34 ◽  
pp. 136-137
Author(s):  
Kenneth A. Taylor ◽  
David A. Grano ◽  
Wah Chiu
Keyword(s):  
Cell Wall ◽  
Negative Bacterium ◽  
Electron Microscopic ◽  
Identical Particles ◽  
Gram Negative ◽  
Microscopic Studies ◽  
Hexagonal Arrangement

Based on chemical and electron microscopic studies (Buckmire and Murray, 1970), the cell wall of Spirillum serpens VHA, a Gram-negative bacterium, is composed of several components including protein, lipopolysaccharide, and peptidoglycan. By a gentle heating of the bacteria at 60°C, the outermost components of the cell wall are separated from the rest of the cell, and can be purified by simple procedures. In the negatively stained preparations, it has been shown by Buckmire and Murray that these components appear in both lamellar and tubular forms made up of identical particles in a closely packed hexagonal arrangement. These particles are approximately 90 Å in diameter, with a center-to-center spacing of approximately 150 Å, and are connected by Y-shaped links.

Changes in the cotyledons of Cucurbita maxima during germination. II. Development of mitochondrial function

1970 ◽  
Vol 48 (12) ◽  
pp. 2233-2240 ◽  
Author(s):  
John N. A. Lott ◽  
Paul Castelfranco
Keyword(s):  
Cytochrome Oxidase ◽  
Mitochondrial Function ◽  
Respiratory Activity ◽  
Succinic Dehydrogenase ◽  
Embryo Axis ◽  
Cucurbita Maxima ◽  
Tissue Slices ◽  
Electron Microscopic ◽  
Fresh Tissue ◽  
Microscopic Studies

Mitochondrial respiration in squash cotyledons was followed during germination. Cytochrome oxidase and succinoxidase activities were determined in isolated mitochondrial preparations; tissue localizations of cytochrome oxidase and succinic dehydrogenase were determined histochemically in fresh tissue slices. The respiratory activities differed in light- and dark-germinated plants. In light-grown plants, the respiratory activity reached a peak at 3 days, when the root and the stem were actively growing, and then declined markedly as the tissue became photosynthetic. During the peak, the respiratory activity was present in all the cotyledon tissues; in the foliaceous cotyledons the respiratory activity was localized in the veins. In dark-grown plants the peak of respiratory activity extended over several days and the respiratory rate remained high throughout the cotyledon's life. This broad peak of activity may be related to the mobilization of storage materials for the growth of the embryo axis. In dark-germinated plants, the respiratory activity was widespread throughout the cotyledonary tissues during the peak of activity; the activity became vein localized by 8 days. Electron microscopic studies of cotyledon tissues showed the presence of many mitochondrial profiles in the veinlet regions.

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