Electron microscopy of two trichomycetous fungi attached to the hindgut lining of pill bugs

1997 ◽  
Vol 75 (9) ◽  
pp. 1479-1484 ◽  
Author(s):  
Masatoshi Saikawa ◽  
Kaori Sugiura ◽  
Hiroki Sato
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Basal Cell ◽  
Distal Portion ◽  
Cross Wall ◽  
Septal Wall ◽  
The Third ◽  
Basal Portion ◽  
Ultrathin Sections ◽  
Lateral Branches

Two species of trichomycetous fungi, Asellaria armadillidii (Asellariales) and Parataeniella armadillidii (Eccrinales), were found attached to the hindgut lining of the pill bug, Armadillidium vulgare. In the former fungus, the thallus was composed of a basal cell bearing an apical whorl of many lateral branches. Electron micrographs in ultrathin sections showed that an electron-opaque holdfast substance surrounded the rhizoidal projections of the basal cell. The cross wall of the thallus was the typical bifurcate type of septum, i.e., the wall flared at the central perforation which was occluded by an electron-opaque plug. This is the third report of this type of septum in the order Asellariales. The bifurcated structure of the septal wall was found to remain at the distal portion of the mature arthrospore cell wall. In P. armadillidii, both primary and secondary infestation sporangiospores were examined in ultrathin sections. A number of electron-transparent pits, 40–50 nm in diameter, were found in the basal portion of the cell wall of secondary infestation sporangiospores which were still contained inside the sporangium. Key words: Asellaria, bifurcate septum, Parataeniella, Trichomycetes.

Electron microscopy of two nematode-destroying fungi, Meristacrum asterospermum and Zygnemomyces echinulatus (Meristacraceae, Entomophthorales)

1997 ◽  
Vol 75 (5) ◽  
pp. 762-768 ◽  
Author(s):  
Masatoshi Saikawa ◽  
Masami Oguchi ◽  
Rafael F. Castañeda Ruiz
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Key Words ◽  
Septal Wall ◽  
Apical Portion ◽  
Key Words Infection ◽  
Ultrathin Sections

Infection of nematodes by Meristacrum asterospermum and Zygnemomyces echinulatus was initiated by conidia adhering to the nematode's cuticle. Each conidium developed an infection peg to penetrate the nematode after adhesion. In M. asterospermum, an infection peg just under the penetration was found in ultrathin sections, in which the peg's cell wall was broken into several lobes that were covered entirely with an amorphous mass of electron-opaque substance. Septa formed in the apical portion of aerial conidiophore under conidiation. The septal wall was nonperforate and often contained electron-opaque inclusions. Vegetative hyphae of Z. echinulatus had typical bifurcate septa, but septa at both ends of the pedicel of conidia were often slightly deformed. Key words: infection of nematodes, Meristacrum asterospermum, septum, Zygnemomyces echinulatus.

Ultrastructure of a marine psychrophilic Vibrio

1970 ◽  
Vol 16 (11) ◽  
pp. 1027-1031 ◽  
Author(s):  
S. F. Kennedy ◽  
R. R. Colwell ◽  
G. B. Chapman
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Division ◽  
Wall Material ◽  
Cross Wall ◽  
Growth Stages ◽  
Culture Age ◽  
Primary Mechanism ◽  
Age Studies

The structure of Vibrio marinus strain PS-207 was studied by both phase and electron microscopy. It was found to possess a trilaminar plasma membrane and cell wall. Membrane-bounded subunits containing DNA-like material were found dispersed throughout the cytoplasm. Giant round forms or "macrospheres" were observed in all growth stages. The size, shape, and construction of the "macrospheres" showed some variation, but could not be related to culture age. Studies of cell division in V. marinus strain PS-207 indicate the primary mechanism to be a synthesis and centripetal deposition of plasma membrane with a concomitant or subsequent synthesis and centripetal deposition of cross wall material.

scholarly journals Electron Microscopy Studies of Cell-Wall-Anchored Cellulose (Avicel)-Binding Protein (AbpS) from Streptomyces reticuli

1999 ◽  
Vol 65 (3) ◽  
pp. 886-892 ◽  
Author(s):  
Stefan Walter ◽  
Manfred Rohde ◽  
Matthias Machner ◽  
Hildgund Schrempf
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Binding Protein ◽  
Crystalline Cellulose ◽  
Terminal Part ◽  
Transmission Electron ◽  
Hydrophobic Amino Acids ◽  
Ultrathin Sections ◽  
Covalently Linked ◽  
Scanning Electron

ABSTRACT Streptomyces reticuli produces a 35-kDa cellulose (Avicel)-binding protein (AbpS) which interacts strongly with crystalline cellulose but not with soluble types of cellulose. Antibodies that were highly specific for the NH2-terminal part of AbpS were isolated by using truncated AbpS proteins that differed in the length of the NH2 terminus. Using these antibodies for immunolabelling and investigations in which fluorescence, transmission electron, or immunofield scanning electron microscopy was used showed that the NH2 terminus of AbpS protrudes from the murein layer of S. reticuli. Additionally, inspection of ultrathin sections of the cell wall, as well as biochemical experiments performed with isolated murein, revealed that AbpS is tightly and very likely covalently linked to the polyglucane layer. As AbpS has also been found to be associated with protoplasts, we predicted that a COOH-terminal stretch consisting of 17 hydrophobic amino acids anchors the protein to the membrane. Different amounts of AbpS homologues of several Streptomyces strains were synthesized.

ELECTRON MICROSCOPY OF ULTRATHIN SECTIONS OF MICROCOCCUS CRYOPHILUS

1966 ◽  
Vol 12 (3) ◽  
pp. 465-469 ◽  
Author(s):  
K. Mazanec ◽  
M. Kocur ◽  
T. Martinec
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Micrococcus Luteus ◽  
Nuclear Material ◽  
Granular Structure ◽  
Condensed Chromatin ◽  
Thin Sections ◽  
Ultrathin Sections

Ultra thin sections of Micrococcus cryophilus cells were investigated. The cell wall, consisting of several layers, measures 410–500 Å and is covered with a distinct capsule. The cytoplasm, which is of granular structure, includes ribosomes, condensed chromatin, and occasionally mesosomes. The nuclear material has various shapes and is formed by filaments proceeding in various directions. We could find no evidence to bear out the supposition of Kocur and Martinec (1962) that M. cryophilus is related to Micrococcus luteus. M. cryophilus is, in its structure as well as its groupings of cells, different from micrococci, which leads us to believe that it does not belong to the genus Micrococcus.

Electron microscopy on a nematode-trapping fungus, Acaulopage pectospora

1985 ◽  
Vol 63 (8) ◽  
pp. 1386-1390 ◽  
Author(s):  
Masatoshi Saikawa ◽  
Chiharu Morikawa
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Electron Density ◽  
Outer Wall ◽  
High Electron ◽  
High Electron Density ◽  
Ultrastructural Evidence ◽  
Lateral Branches ◽  
Dense Vesicles

Trapping organs of Acaulopage pectospora Drechsler, a nematode-destroying fungus, were examined by electron microscopy at various stages of infection. The trapping organs arise from sparsely developed nonseptate hyphae as short, lateral branches, each with a slightly inflated terminal knob. Nematodes arc captured by adhesive secreted from the knob. Electron microscopy revealed the following ultrastructural aspects: (i) the trap's cytoplasm is occupied by large electron-dense vesicles (0.5–0.9 μm) before secretion of the adhesive; (ii) the secreted adhesive derived from the large vesicles has a high electron density and contains a number of bubbles; (iii) the cell wall of the traps becomes doubled after the secretion of adhesive and an aliquot of the adhesive remains in the intervening space between the outer and inner cell wall; (iv) the outer wall of the terminal knob exhibits a rimose appearance. Ultrastructural evidence indicates that Acaulopage pectospora is very similar to Zoophagus insidians Sommerstorff.

Ultrastructure of oospore development in Albugo candida on rapeseed

1977 ◽  
Vol 55 (17) ◽  
pp. 2348-2357 ◽  
Author(s):  
J. P. Tewari ◽  
W. P. Skoropad
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Brassica Campestris ◽  
Active Role ◽  
Albugo Candida ◽  
Transmission Electron ◽  
Ultrathin Sections ◽  
Scanning Electron

The structure and development of oospores of Albugo candida in the stagheads in rapeseed (Brassica campestris) were investigated by light microscopy, transmission electron microscopy of ultrathin sections, and scanning electron microscopy. Development of an oospore, in general, is similar to that in Pythium. A reaction zone is formed in the oogonial wall at the point of contact by the fertilization tube of the antheridium. The oospore has a highly differentiated five-layered cell wall. The periplasm appears to play an active role in deposition of the cell wall of the oospore. Contents of the periplasm do not disappear after maturation of the oospore; instead, they forma persistent material between it and the oogonial wall. Hence, functionally, the oospore wall complex has two additional layers. Longevity of the oospore may be due to the heavily fortified cell wall.

CYTOLOGY OF PHAGE-INFECTED STREPTOMYCES GRISEUS HYPHAE

1965 ◽  
Vol 11 (1) ◽  
pp. 103-107
Author(s):  
C. M. Gilmour ◽  
E. B. Bradford
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Streptomyces Griseus ◽  
Membrane Disruption ◽  
Hexagonal Shape ◽  
Ultrathin Sections ◽  
Irregular Cell

The fine structure of phage-infected Streptomyces griseus hyphae was examined using ultrathin sections and electron microscopy. The intracellular phage was observed to be uniformly distributed throughout the cytoplasm. The diameter and hexagonal shape of the head compared well with shadowed phage preparations. Alterations in fine structure centered on irregular cell wall disintegration, plasma membrane disruption, and leakage of cytoplasmic components.

An electron microscope study of initiation of infection by conidia of Harposporium oxycoracum, an endozoic nematophagous Hyphomycete

1983 ◽  
Vol 61 (3) ◽  
pp. 893-898 ◽  
Author(s):  
Masatoshi Saikawa ◽  
Junko Totsuka ◽  
Chiharu Morikawa
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Germ Tube ◽  
Ruthenium Red ◽  
Convex Side ◽  
En Bloc ◽  
Dense Mass ◽  
Ultrathin Sections

Infective conidia of an endozoic nematophagous hyphomycete, Harposporium oxycoracum Drechsler, were examined by means of electron microscopy. Each of the conidia is very narrow and has a sharply pointed distal and slightly swollen basal end. The swollen basal end was shown, in ultrathin sections stained with ruthenium red en bloc, to be an electron-dense mass of fibrils (ca. 2–3 μm in diameter). The fibrils, thought to be derived from the conidial cell wall, were densely aggregated and were surrounded by a network of more sparsely aggregated fibrils spreading from the fibrous mass of the conidial base. The spreading fibrils seemed to correspond to the mucous droplet observed under the light microscope. It was also found in the present study that the conidia of the fungus were swallowed by nematodes into their lower gut. On germination in the lower gut, a narrow germ tube 5–6 μm wide developed from the convex side of the conidium and produced a simple pore septum at the site of penetration to delimit the empty conidium.

Platinum Compounds as Stains for Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 230-231
Author(s):  
S. K. Aggarwal ◽  
P. McAllister ◽  
R. W. Wagner ◽  
B. Rosenberg
Keyword(s):  
Electron Microscopy ◽  
Hela Cells ◽  
Uranyl Acetate ◽  
Sarcoma 180 ◽  
Platinum Compounds ◽  
Kb Cells ◽  
En Bloc ◽  
Human Lymphoma ◽  
Ultrathin Sections ◽  
Blue Coloration

Uranyl acetate has been used as an electron stain for en bloc staining as well as for staining ultrathin sections in conjunction with various lead stains (Fig. 1). Present studies reveal that various platinum compounds also show promise as electron stains. Certain platinum compounds have been shown to be effective anti-tumor agents. Of particular interest are the compounds with either uracil or thymine as one of the ligands (cis-Pt(II)-uracil; cis-Pt(II)-thymine). These compounds are amorphous, highly soluble in water and often exhibit an intense blue coloration. These compounds show enough electron density to be used as stains for electron microscopy. Most of the studies are based on various cell lines (human AV, cells, human lymphoma cells, KB cells, Sarcoma-180 ascites cells, chick fibroblasts and HeLa cells) while studies on tissue blocks are in progress.

The Ultrastructure of Lymphocytic Hypophysitis

1981 ◽  
Vol 39 ◽  
pp. 466-467
Author(s):  
S.L. Asa ◽  
K. Kovacs ◽  
J. M. Bilbao ◽  
R. G. Josse ◽  
K. Kreines
Keyword(s):  
Electron Microscopy ◽  
Plasma Cells ◽  
Secretory Granules ◽  
Sella Turcica ◽  
Uranyl Acetate ◽  
Lymphocytic Hypophysitis ◽  
Pituitary Cells ◽  
Transmission Electron ◽  
Ultrathin Sections ◽  
Mass Lesions

Seven cases of lymphocytic hypophysitis in women have been reported previously in association with various degrees of hypopituitarism. We report two pregnant patients who presented with mass lesions of the sella turcica, clinically mimicking pituitary adenoma. However, pathologic examination revealed extensive infiltration of the anterior pituitary by lymphocytes and plasma cells with destruction of the gland. To our knowledge, the ultrastructural features of lymphocytic hypophysitis have not been studied so far.For transmission electron microscopy, tissue from surgical specimens was fixed in glutaraldehyde, postfixed in OsO4, dehydrated and embedded in epoxy-resin. Ultrathin sections were stained with uranyl acetate and lead citrate and examined with a Philips 300 electron microscope.Electron microscopy revealed adenohypophysial cells of all types exhibiting varying degrees of injury. In the areas of most dense inflammatory cell infiltration pituitary cells contained large lysosomal bodies fusing with secretory granules (Fig. 1), as well as increased numbers of swollen mitochondria, indicating oncocytic transformation (Fig. 2).

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