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 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.

Ultrastructural aspects of spore germination and outgrowth in Clostridium sporogenes

1969 ◽  
Vol 15 (9) ◽  
pp. 1061-1065 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
C. L. Headley
Keyword(s):  
Cell Wall ◽  
Early Stage ◽  
Nuclear Material ◽  
Spore Coat ◽  
Clostridium Sporogenes ◽  
Thin Sections ◽  
Young Cell ◽  
The Core ◽  
Resting Spore ◽  
Peripheral Areas

The process by which dormant spores of Clostridium sporogenes are transformed into vegetative cells has been studied in thin sections with the electron microscope. The resting spore appears very similar to that of other Bacillaceae for it possesses a rather featureless core which is surrounded by a core membrane, cortex, and spore coat(s); beyond lies a sac-like exosporium. At an early stage in germination the core becomes differentiated into peripheral areas of nuclear material and a ribosome-packed cytoplasm; a germ cell wall develops beyond the core membrane. The later stages of germination coincide with the beginning of outgrowth: the cortex disintegrates into a sponge-like mass of fibrils, and the young cell grows while still retained within the unbroken spore coats. The young cell now has a fibrillar nucleoplasm, a ribosome-rich cytoplasm, an occasional mesosome, a plasma membrane, and a relatively thick cell wall. Subsequently, the cortex vanishes completely, and the new vegetative cell elongates and finally emerges terminally through the spore coats and the exosporium. The exosporium of C. sporogenes consists of two layers: a thick inner one which is laminated, and a thin outer one possessing a fringe of hair-like projections.

scholarly journals Caracteres estructurales y ultraestructurales de la gametogénesis de Chara hydropitys (Charophyceae)

2017 ◽  
Vol 65 (4) ◽  
pp. 1507
Author(s):  
Edgar Javier Rincón Barón ◽  
Yenny Magaly Castrillón Bolaños ◽  
Gerardo Andrés Torres ◽  
Fernando Alzate Guarin ◽  
Silvia Espinosa Matías
Keyword(s):  
Electron Microscopy ◽  
Chromatin Condensation ◽  
Side Wall ◽  
Flagellar Apparatus ◽  
Cytoplasmic Inclusions ◽  
Thin Sections ◽  
Transmission Electron ◽  
Structural Details ◽  
Entire Cell ◽  
Ultrathin Sections

In Charophyceae, the oosporangia and antheridia are the respective female and male structures of sexual reproduction. These organs are characterized by their morphological complexity and usefulness in taxonomy and systematics. Here we described the structural and ultraestructural details of Chara hydropitys gametogenesis. The fertile material from the algae was collected in a tributary stream of the Río Meléndez in Cali, Colombia (3º21´23´´N - 76º32´5.2´´W) in March 2011. The specimens were fixed and processed following the standard protocols for inclusion in resin. Thin sections (0.3-0.5 μm) were stained with toluidine O, and were observed by photonic microscopy, and additional ultrathin sections (60-90 nm) were observed by transmission electron microscopy (TEM); other samples were processed and observed by scanning electron microscopy (SEM). We found that the oosporangia are covered with spiral cells, forming 10-12 convolutions and ends in five coronula cells. The immature oosporangia wall is formed by two layers that correspond to the wall of the spiral cells and to the oosphere. In mature stages, the oosporangia wall is composed by six additional layers, three of them are provided by the oosphere and the other three are provided by the spiral cells. Oosphere size increases progressively while the spiral cells grow and divide. The cytoplasm of the immature oosphere does not exhibit conspicuous cytoplasmic inclusions, nevertheless, with the maturation, the number of starch granules increases, occupying most of the cell volume. In the spiral cells of the mature oosporangia we observed large number of chloroplast with starch accumulations, between thylakoid lamellae and a vacuole that occupies almost the entire cell. By using SEM it was possible to appreciate, that the external wall of the oospore, more accurately, on the fossa area, shows verrucose micro-ornamentations with verrucae elevations. In mature antheridia, shield cells are strongly pigmented orange due to the presence of a large number of plastoglobules between thylakoid lamellae. The spermatogenous filaments are developed from cells of the secondary capitulum; those, by unidirectional and sincronic mitotic divisions develop the spermatocytes. The biflagellate antherozoids are developed from the haploid cells by spermiogenesis. The subcellular events related with these division and differentiation processes, include first, chromatin condensation, loss of nucleoli and more activity in dictyosomes. Subsequently, retracts the cytoplasm and the organelles are aligned along the condensed nucleus and flagellar apparatus. Mature antherozoids emerge through a side wall pore of the spermatocytes. All the described events showed that the gametogenesis processes and the gametes structural details in general, are widely conserved in this algae group.

Electron microscopic analysis of objects in light microscopic sections

1978 ◽  
Vol 36 (2) ◽  
pp. 80-81
Author(s):  
Arvid B. Maunsbach
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Microscopic Analysis ◽  
Electron Microscopic Level ◽  
Semithin Section ◽  
Cover Glass ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Glass Slides ◽  
Ultrathin Sections

Structural studies in experimental biology or in pathology are frequently extended from the light to the electron microscopic level. This is often done by cutting both semithin (about 1 μm) and thin sections from the same tissue block after embedding for electron microscopy. However, in many studies it would be of great value to analyse the same structure both by light and electron microscopy, i.e. to be able to study by electron microscopy an object which is first detected by light microscopy in a semithin section. To achieve this, a method has been developed by which ultrathin sections are cut directly from the semithin section containing the object of interest.Semithin sections, about 1 μ in thickness, are cut from Epon or Vestopal embedded tissue. The sections are placed on ordinary glass slides and stained with toluidine blue. The sections are studied in the light microscope without a cover glass or mounted in water.

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.

Preparation of Ultrathin Sections of Polymeric Materials

1963 ◽  
Vol 36 (3) ◽  
pp. 799-802
Author(s):  
K. Kh. Razikov ◽  
G. S. Markova
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Electron Diffraction ◽  
Present Article ◽  
Ultrathin Section ◽  
Polymeric Materials ◽  
Thermal Regulation ◽  
Polymeric Fibers ◽  
Thin Sections ◽  
Ultrathin Sections

Abstract Much importance attaches at the present time to the use of ultrathin sections for the investigation of the structure of polymeric materials by electron microscopy, electron diffraction and other methods. Extremely thin sections (down to hundredths of a micron) can be prepared by means of ultramicrotomes in which thermal regulation of the feed of the specimen is provided. The use of ultramicrotomes in various branches of sciences has given valuable information on the fine structure of many substances. In the present article we describe the use of the ultrathin section method for the investigation of the structure of polymers by means of an ultramicrotome of the “Sjostrand Ultra-microtome LKB-Producter” type. As a result of the elasticity of polymeric materials the preparation of thin sections is rendered difficult. Therefore the development of a method of producing ultrathin sections of polymeric materials is of considerable interest. We have developed such a method for the study of the structure of thin polymeric fibers (of diameter 15 to 20 µ) of thick monofilament (of diameter 0.5 mm and above) and also of films. The technique of preparation of ultrathin sections consists of the following stages: 1) embedding the specimens for investigation; 2) preparation of the specimen for cutting; 3) preparation of the knives; and 4) preparation of the apparatus and cutting.

scholarly journals DEVELOPMENT AND GERMINATION OF THE AZOTOBACTER CYST

1961 ◽  
Vol 10 (4) ◽  
pp. 555-565 ◽  
Author(s):  
Orville Wyss ◽  
Marilyn G. Neumann ◽  
M. D. Socolofsky
Keyword(s):  
Cell Wall ◽  
Vegetative Cell ◽  
Central Body ◽  
Azotobacter Vinelandii ◽  
Nuclear Material ◽  
Spherical Form ◽  
Cyst Volume ◽  
Ultrathin Sections ◽  
Mature Cyst ◽  
Cyst Germination

The fine structure of Azotobacter vinelandii has been studied by means of electron microscopy of ultrathin sections made of the encysting and germinating cells. The organisms were fixed with KMnO4 and embedded in epoxy resin. On an encystment medium the rod-shaped bacteria begin to assume an almost spherical form and then bark-like exine appears in 1½ to 2 days. The exine thickens and an electron permeable intine forms between it and the shrinking cell body. In 5 days the intine makes up more than half of the cyst volume and begins to show a definite two-layered structure. Meanwhile the peripheral bodies, which may be extensions of the cell membrane of the vegetative cell, disappear as the encystment progresses. The cell wall and membrane of the vegetative cell remain demonstrable as the confining structure of the shrinking central body of the mature cyst. In this central body lipoidal globules appear together with aggregations of nuclear material. Cyst germination begins with an increase in the size of the central body at the expense of the intine. The nuclear aggregations become more diffuse and the lipoidal globules disappear. The exine may be pushed outward and the bark-like fragments separate as the emerging vegetative cell develops. Invagination of the cell wall and membrane may occur at this stage leading to cell division. Empty exines remain as horseshoe-shaped structures.

scholarly journals THE COMPOSITION AND STRUCTURE OF BACTERIAL SPORES

1963 ◽  
Vol 16 (3) ◽  
pp. 579-592 ◽  
Author(s):  
A. D. Warth ◽  
D. F. Ohye ◽  
W. G. Murrell
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Diaminopimelic Acid ◽  
Bacterial Spores ◽  
Bacillus Species ◽  
Thin Sections ◽  
Composition And Structure ◽  
Soluble Fractions

The composition of the insoluble "integuments" and soluble "contents" fractions of spores of four Bacillus species of widely differing heat resistance were compared. Electron microscopy of thin sections was also used to determine and compare the morphological structures in the integument preparations. The soluble fractions of the thermophiles, B. coagulans and B. stearothermophilus, had a higher content of hexose and dipicolinic acid. The hexose content of both fractions of the four species was related to heat resistance. Integument fractions consisted chiefly of protein together with variable amounts of the mucopeptide constituents, α, ϵ-diaminopimelic acid (DAP) and hexosamine. In the thermophiles the DAP and hexosamine were found chiefly in the insoluble integuments fractions, while in B. cereus and B. subtilis most of this material was soluble. Integument preparations, containing mainly protein with little mucopeptide, consisted chiefly of outer and inner spore coats, while preparations having more mucopeptide contained also residual cortical material and a cortical membrane (possibly the germ cell wall). The results suggest that spore integuments consist of mainly proteinaceous outer and inner coats together with variable amounts of residual cortex and cortical membrane which contain the mucopeptide material.

Dimorphism of Penicillium marneffei as observed by electron microscopy

1973 ◽  
Vol 19 (10) ◽  
pp. 1305-1309 ◽  
Author(s):  
Robert G. Garrison ◽  
Karen S. Boyd
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Penicillium Marneffei ◽  
Lipid Bodies ◽  
Hyphal Cell ◽  
Dimorphic Fungi ◽  
Thin Sections ◽  
Internal Morphology ◽  
Tissue Phase ◽  
Altered Lipid

Aspects of the culturally induced mycelial- to tissue-phase transformation of Penicillium marneffei were studied by electron microscopy of thin sections. The hyphal cell was observed to contain multiple, large lipid bodies scattered throughout the cytoplasm. Five days after induction of conversion, short elements arose which were characterized by the presence of two polar areas of vacuolation containing electron-opaque material thought to be altered lipid. This material could not be demonstrated with permanganate fixation, but reacted strongly with thiocarbohydrazide. The latter reagent is known to enhance the electron density of osmium-stained lipids. After 10 days incubation, the tissue-phase cells appeared to be slightly elongate with one or more septa present as the result of division by fission. The cell wall appeared to be of uniform electron opacity with a slightly roughened appearance to the outer surface. Except for residuals of polar vacuolation, the internal morphology of the tissue phase of P. marneffei appeared similar in many respects to that of the analogous yeast-like phases of certain other of the pathogenic dimorphic fungi.

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